U.S. patent application number 13/223103 was filed with the patent office on 2012-04-19 for uniquely identifying target femtocell to facilitate femto-assisted active hand-in.
This patent application is currently assigned to QUALCOMM Incorporated. Invention is credited to Olufunmilola O. Awoniyi, Jen M. Chen, Jangwon Lee, Andrei D. Radulescu, Damanjit Singh, Samir S. Soliman, Mehmet Yavuz.
Application Number | 20120094666 13/223103 |
Document ID | / |
Family ID | 45934584 |
Filed Date | 2012-04-19 |
United States Patent
Application |
20120094666 |
Kind Code |
A1 |
Awoniyi; Olufunmilola O. ;
et al. |
April 19, 2012 |
UNIQUELY IDENTIFYING TARGET FEMTOCELL TO FACILITATE FEMTO-ASSISTED
ACTIVE HAND-IN
Abstract
Systems, methods, and devices are described for supporting
macrocell-to-femtocell hand-ins of active macro communications for
mobile devices. An out-of-band (OOB) link is used to detect that a
mobile device is in proximity of a femtocell. Having detected the
mobile device in proximity to the femtocell, an OOB proximity
detection is communicated to a femtocell gateway disposed in a core
network in communication with the macro network to effectively
pre-register the mobile device with the femto-convergence system.
When the femtocell gateway receives a handover request from the
macro network implicating the pre-registered mobile device, it is
able to reliably determine the appropriate target femtocell to use
for the hand-in according to the pre-registration, even where
identification of the appropriate target femtocell would otherwise
be unreliable. Some embodiments may also handling registering the
mobile device after a handover request has occurred, including
tiered approaches.
Inventors: |
Awoniyi; Olufunmilola O.;
(San Diego, CA) ; Soliman; Samir S.; (San Diego,
CA) ; Lee; Jangwon; (San Diego, CA) ;
Radulescu; Andrei D.; (San Diego, CA) ; Singh;
Damanjit; (San Diego, CA) ; Chen; Jen M.; (San
Diego, CA) ; Yavuz; Mehmet; (San Diego, CA) |
Assignee: |
QUALCOMM Incorporated
San Diego
CA
|
Family ID: |
45934584 |
Appl. No.: |
13/223103 |
Filed: |
August 31, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61393533 |
Oct 15, 2010 |
|
|
|
Current U.S.
Class: |
455/435.1 |
Current CPC
Class: |
H04W 36/0055 20130101;
H04W 36/0058 20180801; H04W 84/045 20130101; H04W 36/04 20130101;
H04W 48/16 20130101 |
Class at
Publication: |
455/435.1 |
International
Class: |
H04W 36/04 20090101
H04W036/04; H04W 60/00 20090101 H04W060/00 |
Claims
1. A method for macrocell-to-femtocell hand-in comprising:
detecting a user equipment in proximity to a femtocell using an
out-of-band (OOB) communications link; identifying a user equipment
identifier corresponding to the user equipment detected in
proximity to the femtocell using the OOB communications link; and
registering the user equipment for hand-in from a macrocell to the
femtocell by communicating, from the femtocell to a femtocell
gateway, the user equipment identifier and indicating OOB proximity
detection of the user equipment at the femtocell.
2. The method of claim 1, wherein identifying the user equipment
identifier comprises receiving an OOB identifier associated with
the user equipment identifier over the OOB communications link.
3. The method of claim 1, wherein identifying the user equipment
identifier comprises receiving a macro identifier associated with
the user equipment identifier over the OOB communications link.
4. The method of claim 1, wherein registering the user equipment
for hand-in from the macrocell to the femtocell comprises
transmitting a registration message from the femtocell to the
femtocell gateway.
5. The method of claim 1, wherein registering the user equipment
for hand-in from the macrocell to the femtocell comprises
transmitting an OOB indication message from the femtocell to the
femtocell gateway.
6. The method of claim 2, further comprising: utilizing a user
equipment mapping between a macro identifier of the user equipment
with the OOB identifier to determine the user equipment
identifier.
7. The method of claim 2, wherein detecting the user equipment in
proximity to the femtocell comprises: paging the user equipment
over the OOB communications link; and detecting a response to the
paging from the user equipment over the OOB communications link,
wherein the response comprises the OOB identifier of the user
equipment.
8. The method of claim 1, further comprising: receiving a handover
request for the user equipment at the femtocell from the femtocell
gateway, the handover request being configured to direct the user
equipment to hand off active communications with the macro network
from the macrocell to the femtocell.
9. The method of claim 8, wherein the handover request is received
subsequent to registering the user equipment for hand-in from the
macrocell to the femtocell.
10. The method of claim 8, wherein: the handover request is
received prior to registering the user equipment for hand-in from
the macrocell to the femtocell; and detecting the user equipment
comprises detecting the user equipment in response to receiving the
handover request.
11. The method of claim 10, wherein detecting the user equipment in
response to receiving the handover request comprises: detecting the
user equipment over the OOB communications link utilizing an OOB
identifier of the user equipment.
12. The method of claim 1, further comprising: detecting a loss of
the OOB communications link between the user equipment and the
femtocell; and de-registering the user equipment according to
detecting the loss of the OOB communications link.
13. The method of claim 10, wherein registering the user equipment
further comprises transmitting a handover response accepting the
handover request.
14. The method of claim 1, wherein the femtocell is one of a
plurality of femtocells on a macro network, each femtocell having a
first femtocell identifier according to which the femtocell is
non-uniquely addressable by the macro network and a second
femtocell identifier according to which the femtocell is uniquely
addressable by the femtocell gateway.
15. The method of claim 1, wherein the OOB communications link
comprises a Bluetooth link.
16. The method of claim 14, wherein the first femtocell identifier
of each respective femtocell comprises a primary scrambling code
(PSC) of the respective femtocell.
17. The method of claim 1, wherein the user equipment identifier
comprises a macro identifier associated with the user
equipment.
18. The method of claim 17, wherein the macro identifier comprises
a International Mobile Subscriber Identity (IMSI) associated with
the user equipment.
19. A femtocell comprising: an in-band frequency module,
communicatively coupled with a macro network via a femtocell
gateway and configured to provide cellular network access to user
equipments; an out-of-band (OOB) frequency module, communicatively
coupled with the in-band frequency module and configured to
communicate with the user equipments over an OOB communications
link; and a communications management subsystem, communicatively
coupled with the in-band frequency module and the OOB frequency
module, and configured to: detect a user equipment in proximity to
the femtocell using an out-of-band (OOB) communications link;
identify a user equipment identifier corresponding to the user
equipment detected in proximity to the femtocell using the OOB
communications link; and register the user equipment for hand-in
from a macrocell to the femtocell by communicating, from the
femtocell to a femtocell gateway, the user equipment identifier and
indicating OOB proximity detection of the user equipment at the
femtocell.
20. The femtocell of claim 19, wherein the communications
management subsystem configured to identify the user equipment
identifier comprises a configuration to receive a macro identifier
associated with the user equipment identifier over the OOB
communications link.
21. The femtocell of claim 19, wherein the communications
management subsystem configured to identify the user equipment
identifier comprises a configuration to receive an OOB identifier
associated with the user equipment identifier over the OOB
communications link.
22. The femtocell of claim 19, wherein the communications
management subsystem configured to register the user equipment
comprises a configuration to transmit a registration message from
the femtocell to the femtocell gateway.
23. The femtocell of claim 19, wherein the communications
management subsystem configured to register the user equipment
comprises a configuration to transmit an OOB indication message
from the femtocell to the femtocell gateway.
24. The femtocell of claim 21, wherein the communications
management subsystem is further configured to: utilize a user
equipment mapping between a macro identifier of the user equipment
with the OOB identifier to determine the user equipment
identifier.
25. The femtocell of claim 20, wherein the communications
management subsystem configured to detect the user equipment in
proximity to the femtocell is further configured to: page the user
equipment over the OOB communications link; and detect a response
to the paging from the user equipment over the OOB communications
link, wherein the response comprises the macro identifier of the
user equipment.
26. The femtocell of claim 19, wherein the communications
management subsystem is further configured to: receive a handover
request for the user equipment at the femtocell from the femtocell
gateway, the handover request being configured to direct the user
equipment to hand off active communications with the macro network
from the macrocell to the femtocell.
27. The femtocell of claim 26, wherein the handover request is
received subsequent to registering the user equipment for hand-in
from the macrocell to the femtocell.
28. The femtocell of claim 26, wherein: the handover request is
received prior to registering the user equipment for hand-in from
the macrocell to the femtocell; and the communications management
subsystem configured to detect the user equipment comprises
detecting the user equipment in response to receiving the handover
request.
29. The femtocell of claim 28, wherein the communications
management subsystem configured to detect the user equipment in
response to receiving the handover request comprises a
configuration to: detect the user equipment over the OOB
communications link utilizing an OOB identifier of the user
equipment.
30. The femtocell of claim 19, wherein the communications
management subsystem is further configured to: detect a loss of the
OOB communications link between the user equipment and the
femtocell; and de-register the user equipment according to
detecting the loss of the OOB communications link.
31. The femtocell of claim 28, wherein the communications
management subsystem is further configured to: transmit a handover
response accepting the handover request as part of registering the
user equipment.
32. The femtocell of claim 19, wherein the femtocell is one of a
plurality of femtocells on a cellular network, each femtocell
having a first femtocell identifier according to which the
femtocell is non-uniquely addressable by the macro network and a
second femtocell identifier according to which the femtocell is
uniquely addressable by the femto gateway.
33. A processor for macrocell-to-femtocell hand-in, the processor
comprising: a communications management controller configured to:
detect a user equipment in proximity to the femtocell using an
out-of-band (OOB) communications link; identify a user equipment
identifier corresponding to the user equipment detected in
proximity to the femtocell using the OOB communications link; and
register the user equipment for hand-in from a macrocell to the
femtocell by communicating, from the femtocell to a femtocell
gateway, the user equipment identifier and indicating OOB proximity
detection of the user equipment at the femtocell.
34. A computer program product for macrocell-to-femtocell hand-in
residing on a processor-readable medium and comprising
processor-readable instructions, which, when executed, cause a
processor to perform steps comprising: detecting a user equipment
in proximity to a femtocell using an out-of-band (OOB)
communications link; identifying a user equipment identifier
corresponding to the user equipment detected in proximity to the
femtocell using the OOB communications link; and registering the
user equipment for hand-in from a macrocell to the femtocell by
communicating, from the femtocell to a femtocell gateway, the user
equipment identifier and indicating OOB proximity detection of the
user equipment at the femtocell.
35. A system for macrocell-to-femtocell hand-in comprising: means
for detecting a user equipment in proximity to the femtocell using
an out-of-band (OOB) communications link; means for identifying a
user equipment identifier corresponding to the user equipment
detected in proximity to the femtocell using the OOB communications
link; and means for registering the user equipment for hand-in from
a macrocell to the femtocell by communicating, from the femtocell
to a femtocell gateway, the user equipment identifier and
indicating OOB proximity detection of the user equipment at the
femtocell.
36. A method for macrocell-to-femtocell hand-in, the method
comprising: receiving, at a femtocell gateway from a macro network,
a handover request configured to direct a user equipment to hand
off active communications with the macro network from a macrocell
to a designated femtocell with a first femtocell identifier;
determining, at the femtocell gateway, whether any of a plurality
of femtocells registered the user equipment with the femtocell
gateway prior to receiving the handover request; and communicating,
from the femtocell gateway, the handover request to the designated
femtocell.
37. The method of claim 36, wherein determining, at the femtocell
gateway, whether any of the plurality of femtocells registered the
user equipment with the femtocell gateway prior to receiving the
handover request comprises: determining a registering femtocell
from the plurality of femtocells that has registered the user
equipment prior to receiving the handover request; and determining
that the registering femtocell is the designated femtocell with the
first femtocell identifier.
38. The method of claim 37, further comprising: receiving an
acknowledgement message from the registering femtocell.
39. The method of claim 36, wherein determining, at the femtocell
gateway, whether any of the plurality of femtocells registered the
user equipment with the femtocell gateway prior to receiving the
relocation request comprises: determining that none of the
plurality of femtocells registered the user equipment prior to
receiving the handover request.
40. The method of claim 39, further comprising: determining a set
of candidate femtocells from the plurality of femtocells registered
at the femto gateway, wherein the set of candidate femtocells is
identified by at least the first femtocell identifier; directing
each of the set of candidate femtocells to detect whether the user
equipment is in its proximity; receiving an indication from a
successful femtocell of the candidate femtocells that the user
equipment is in its proximity; and determining that the successful
femtocell is the designated femtocell.
41. The method of claim 40, further comprising: monitoring an
elapsed time subsequent to directing the set of candidate
femtocells to detect whether the user equipment is in its
proximity; and determining whether the indication from one of the
candidate femtocells that the user equipment is in its proximity is
received while the elapsed time is within a predefined time
limit.
42. The method of claim 36, wherein determining, at the femtocell
gateway, whether any of the plurality of femtocells registered the
user equipment prior to receiving the handover request comprises:
determining whether an OOB proximity detection is received from any
of the plurality of femtocells prior to receiving the handover
request, wherein the OOB proximity indication comprises a macro
identifier of the user equipment.
43. The method of claim 36, wherein determining, at the femtocell
gateway, whether any of the plurality of femtocells registered the
user equipment prior to receiving the handover request comprises:
determining whether an OOB proximity indication is received from
any of the plurality of femtocells prior to receiving the handover
request, wherein the OOB proximity indication comprises an OOB
identifier of the user equipment; and determining a macro
identifier of the user equipment corresponding to the OOB
identifier of the user equipment.
44. The method of claim 36, further comprising: determining whether
the designated femtocell is uniquely addressable by the femtocell
gateway according to the first femtocell identifier; and wherein
communicating, from the femtocell gateway, the handover request to
designated femtocell utilizes the first femtocell identifier.
45. The method of claim 36, wherein determining, at the femtocell
gateway, whether any of the plurality of femtocells registered the
user equipment prior to receiving the handover request comprises:
determining whether two or more femtocells of the plurality of
femtocells are addressable by the femtocell gateway according to
the first femtocell identifier; and determining whether the
designated femtocell is one of the two or more femtocells
addressable according to the first femtocell identifier utilizing a
second femtocell identifier.
46. The method of claim 39, further comprising: determining a set
of candidate femtocells from the plurality of femtocells; and
directing, using an OOB hand-in cause value in the handover
request, each of the set of candidate femtocells to detect whether
the user equipment is in its proximity.
47. The method of claim 46, further comprising: receiving an OOB
accept message from one of the candidate femtocells, wherein the
OOB accept message indicates that the one of the candidate
femtocells detects the user equipment in its proximity; and
identifying one of the candidate cells associated with the OOB
accept message as the designated femtocell.
48. The method of claim 46, further comprising: receiving at least
an OOB reject message from one or more of the candidate femtocells
or an error indication message from one or more of the candidate
femtocells and no OOB accept messages; and transmitting to each of
the candidate femtocells a handover request with a normal cause
value.
49. The method of claim 48, further comprising: receiving at least
a blind accept or a blind reject from one or more of the candidate
femtocells; and identifying one of the candidate femtocells
associated with a blind accept as the designated femtocell.
50. A femtocell gateway comprising: a macro network interface
subsystem configured to communicate with a core node of a macro
network and configured to receive communications from the macro
network; a femtocell interface subsystem configured to communicate
with a plurality of femtocells; and a communications management
subsystem, communicatively coupled with the macro network interface
subsystem and the femtocell interface subsystem, and configured to:
receive, from the macro network, a handover request configured to
direct a user equipment to hand off active communications with the
macro network from a macrocell to a designated femtocell with a
first femtocell identifier; determine whether any of the plurality
of femtocells registered the user equipment with the femtocell
gateway prior to receiving the handover request; and communicate
the handover request to designated femtocell.
51. The femtocell gateway of claim 50, wherein to determine whether
any of the plurality of femtocells registered the user equipment
with the femtocell gateway prior to receiving the handover request,
the communications management subsystem is configured to: determine
a registering femtocell from the plurality of femtocells that has
registered the user equipment prior to receiving the handover
request; and determine that the registering femtocell is the
designated femtocell with the first femtocell identifier.
52. The femtocell gateway of claim 51, wherein the communications
management subsystem is further configured to: receive an
acknowledgement message from the registering femtocell.
53. The femtocell gateway of claim 50, wherein to determine whether
any of the plurality of femtocells registered the user equipment
with the femtocell gateway prior to receiving the handover request,
the communications management subsystem is configured to: determine
that none of the plurality of femtocells registered the user
equipment prior to receiving the handover request.
54. The femtocell gateway of claim 53, wherein the communications
management subsystem is further configured to: determine a set of
candidate femtocells from the plurality of femtocells, wherein the
candidate femtocells are identified by at least the first femtocell
identifier; direct each of the candidate femtocells to detect
whether the user equipment is in its proximity; receive an
indication from a successful femtocell of the candidate femtocells
that the user equipment is in its proximity; and determine that the
successful femtocell is the designated femtocell.
55. The femtocell gateway of claim 54, wherein the communications
management subsystem is further configured to: monitor an elapsed
time subsequent to directing the set of candidate femtocells to
detect whether the user equipment is in its proximity; and
determine whether the indication from one of the candidate
femtocells that the user equipment is in its proximity is received
while the elapsed time is within a predefined time limit.
56. The femtocell gateway of claim 50, wherein to determine whether
any of the plurality of femtocells registered the user equipment
with the femtocell gateway prior to receiving the handover request,
the communications management subsystem is further configured to:
determine whether an OOB proximity indication is received from any
of the plurality of femtocells prior to receiving the handover
request, wherein the OOB proximity indication comprises a macro
identifier of the user equipment.
57. The femtocell gateway of claim 50, wherein to determine whether
any of the plurality of femtocells registered the user equipment
with the femtocell gateway prior to receiving the handover request,
the communications management subsystem is further configured to:
determine whether an OOB proximity detection is received from any
of the plurality of femtocells prior to receiving the handover
request, wherein the OOB proximity indication comprises an OOB
identifier of the user equipment; and determine a macro identifier
of the user equipment corresponding to the OOB identifier of the
user equipment.
58. The femtocell gateway of claim 50, wherein the communications
management subsystem is further configured to: determine whether
the designated femtocell is uniquely addressable by the femtocell
gateway according to the first femtocell identifier; and wherein
communicating the handover request to designated femtocell utilizes
the first femtocell identifier.
59. The femtocell gateway of claim 50, wherein the communications
management subsystem configured to determine whether any of the
plurality of femtocells registered the user equipment prior to
receiving the handover request comprises a configuration to:
determine whether two or more femtocells of the plurality of
femtocells are addressable by the femtocell gateway according to
the first femtocell identifier; and determine whether the
designated femtocell is one of the two or more femtocells
addressable according to the first femtocell identifier utilizing a
second femtocell identifier.
60. The femtocell gateway of claim 53, wherein the communications
management subsystem is further configured to: determine a set of
candidate femtocells from the plurality of femtocells; and direct,
using an OOB hand-in cause value in the handover request, each of
the candidate femtocells to detect whether the user equipment is in
its proximity.
61. The femtocell gateway of claim 60, wherein the communications
management subsystem is further configured to: receive an OOB
accept message from one of the candidate femtocells, wherein the
OOB accept message indicates that the one of the candidate
femtocells detects the user equipment in its proximity; and
identify the one of the candidate cells as the designated
femtocell.
62. The femtocell gateway of claim 60, wherein the communications
management subsystem is further configured to: receive at least an
OOB reject message from one or more of the candidate femtocells or
an error indication message from one or more of the candidate
femtocells and no OOB accept messages; and transmit to each of the
candidate femtocells a handover request with a normal cause
value.
63. The femtocell gateway of claim 62, wherein the communications
management subsystem is further configured to: receive at least a
blind accept or a blind reject from one or more of the candidate
femtocells; and identify one of the candidate femtocells associated
with a blind accept as the designated femtocell.
64. A processor for macrocell-to-femtocell hand-in in a femtocell
gateway, the processor comprising: a communications management
controller configured to: receive, from the macro network, a
handover request configured to direct a user equipment to hand off
active communications with the macro network from a macrocell to a
designated femtocell with a first femtocell identifier; determine
whether any of a plurality of femtocells registered the user
equipment with the femtocell gateway prior to receiving the
handover request; and communicate the handover request to the
designated femtocell.
65. A computer program product for macrocell-to-femtocell hand-in
residing on a processor-readable medium disposed at a femtocell
gateway and comprising processor-readable instructions, which, when
executed, cause a processor to perform steps comprising: receiving,
from a macro network, a handover request configured to direct a
user equipment to hand off active communications with the macro
network from a macrocell to a designated femtocell with a first
femtocell identifier; determining whether any of a plurality of
femtocells registered the user equipment with the femtocell gateway
prior to receiving the handover request; and communicating the
handover request to the designated femtocell.
66. A system for macrocell-to-femtocell hand-in comprising: means
for receiving, from a macro network, a handover request configured
to direct a user equipment to hand off active communications with
the macro network from a macrocell to a designated femtocell with a
first femtocell identifier; means for determining whether any of a
plurality of femtocells registered the user equipment with the
femtocell gateway prior to receiving the handover request; and
means for communicating the handover request to the designated
femtocell.
Description
CROSS REFERENCES
[0001] The present Application claims priority to Provisional
Application No. 61/393,533 entitled "Uniquely Identifying Target
Femtocell to Facilitate Femto-Assisted Active Hand-in" filed Oct.
15, 2010, and assigned to the assignee hereof and hereby expressly
incorporated by reference herein. This application is also related
to: U.S. patent application Ser. No. ______, entitled "PROXIMITY
DETECTION FOR FEMTOCELLS USING OUT-OF-BAND LINKS," and referenced
as Qualcomm Docket No. 102971, and U.S. patent application Ser. No.
______, entitled "FEMTOCELL INDICATION OF MOBILE DEVICE PROXIMITY
AND TRANSMISSION OF MOBILE IDENTITY TO ASSIST IN RESOLVING
FEMTOCELL DISAMBIGUATION," and referenced as Qualcomm Docket No.
110936, each assigned to the assignee hereof and hereby expressly
incorporated by reference herein.
BACKGROUND
[0002] Communication networks are in wide use today, and often have
multiple devices in communication over wireless links to carry
voice and data. Many of these devices, such as cellular phones,
smartphones, laptops, and tablets, are mobile, and may connect with
a network wirelessly via a base station, access point, wireless
router, or Node B (collectively referred to herein as "access
points"). A mobile device may remain within the service area of
such an access point for a relatively long period of time (thereby
being "camped on" the access point) or may travel relatively
rapidly through access point service areas, with cellular handover
or reselection techniques being used for maintaining a
communication session, or for idle mode operation as association
with access points is changed.
[0003] Issues with respect to available spectrum, bandwidth, or
capacity may result in an access being unavailable or inadequate
between certain mobile devices and an access point. Likewise,
issues with respect to wireless signal propagation (e.g.,
shadowing, multipath fading, interference, etc.) may result in
access being unavailable for particular mobile devices.
[0004] Cellular networks have employed the use of various cell
types, such as macrocells, microcells, picocells, and femtocells,
to provide desired bandwidth, capacity, and wireless communication
coverage within service areas. Femtocells may be used to provide
wireless communication in areas of poor network coverage (e.g.,
inside of buildings), to provide increased network capacity, and to
utilize broadband network capacity for backhaul. There may be a
need in the art for novel functionality to accurately identify
femtocells for a macrocell to femtocell hand-in.
SUMMARY
[0005] The present disclosure is directed to systems and methods
for supporting macrocell-to-femtocell hand-ins of active macro
communications for mobile devices. A femtocell detects a mobile
device in its proximity (e.g., using an out-of-band link
established by an out-of-band radio integrated with the femtocell
as part of a femto-proxy system). Having detected the mobile device
in its proximity, the femtocell communicates an OOB presence
indicator to pre-register the mobile device with a femtocell
gateway (e.g., another type of interface gateway) disposed in a
core network in communication with the macro network. When the
femtocell gateway receives a handover request from the macro
network implicating the pre-registered mobile device, the femtocell
gateway is able to reliably determine the appropriate femtocell to
use for the hand-in according to the OOB presence indication. The
OOB presence indication can be carried in an existing message
between femtocell and femtocell gateway such as a registration
message, handover response message, or an OOB presence message can
be defined to communicate this indication.
[0006] Some embodiments include a method for macrocell-to-femtocell
hand-in. A user equipment may be in proximity to a femtocell using
an out-of-band (OOB) communications link. A user equipment
identifier may be identified corresponding to the user equipment
detected in proximity to the femtocell using the OOB communications
link. The user equipment may be registered for hand-in from a
macrocell to the femtocell by communicating, from the femtocell to
a femtocell gateway, the user equipment identifier and indicating
OOB proximity detection of the user equipment at the femtocell.
[0007] Identifying the user equipment identifier may include
receiving an OOB identifier associated with the user equipment
identifier over the OOB communications link. Identifying the user
equipment identifier may include receiving a macro identifier
associated with the user equipment identifier over the OOB
communications link. Registering the user equipment for hand-in
from the macrocell to the femtocell may include transmitting a
registration message from the femtocell to the femtocell gateway.
Registering the user equipment for hand-in from the macrocell to
the femtocell may include transmitting an OOB indication message
from the femtocell to the femtocell gateway.
[0008] In some embodiments, the method for macrocell-to-femtocell
hand-in may further include utilizing a user equipment mapping
between a macro identifier of the user equipment with the OOB
identifier to determine the user equipment identifier. Detecting
the user equipment in proximity to the femtocell may include paging
the user equipment over the OOB communications link; and detecting
a response to the paging from the user equipment over the OOB
communications link. The response may include the OOB identifier of
the user equipment. In some embodiments, the response may include
the macro identifier for the user equipment.
[0009] In some embodiments, the method for macrocell-to-femtocell
hand-in may further include receiving a handover request for the
user equipment at the femtocell from the femtocell gateway, the
handover request being configured to direct the user equipment to
hand off active communications with the macro network from the
macrocell to the femtocell. The handover request may be received
subsequent to registering the user equipment for hand-in from the
macrocell to the femtocell. The handover request may be received
prior to registering the user equipment for hand-in from the
macrocell to the femtocell; and detecting the user equipment may
include detecting the user equipment in response to receiving the
handover request. Detecting the user equipment in response to
receiving the handover request may include detecting the user
equipment over the OOB communications link utilizing an OOB
identifier of the user equipment. In some embodiments, detecting
the user equipment in response to receiving the handover request
may include detecting the user equipment over the OOB
communications link utilizing a macro identifier of the user
equipment. Registering the user equipment may further include
transmitting a handover response accepting the handover
request.
[0010] In some embodiments, the method for macrocell-to-femtocell
hand-in may further include detecting a loss of the OOB
communications link between the user equipment and the femtocell.
The user equipment may be de-registered according to detecting the
loss of the OOB communications link.
[0011] In some embodiments, the femtocell is one of multiple
femtocells on a macro network, each femtocell having a first
femtocell identifier according to which the femtocell is
non-uniquely addressable by the macro network and a second
femtocell identifier according to which the femtocell is uniquely
addressable by the femtocell gateway. In some embodiments, the OOB
communications link includes a Bluetooth link. The first femtocell
identifier of each respective femtocell may include a primary
scrambling code (PSC) of the respective femtocell. The user
equipment identifier may include a macro identifier associated with
the user equipment. The macro identifier may include a
International Mobile Subscriber Identity (IMSI) associated with the
user equipment.
[0012] Some embodiments include a femtocell that may include an
in-band frequency module, communicatively coupled with a macro
network via a femtocell gateway and configured to provide cellular
network access to user equipments. The femtocell may include an
out-of-band (OOB) frequency module, communicatively coupled with
the in-band frequency module and configured to communicate with the
user equipments over an OOB communications link. The femtocell may
include a communications management subsystem, communicatively
coupled with the in-band frequency module and the OOB frequency
module, and configured to: detect a user equipment in proximity to
the femtocell using an out-of-band (OOB) communications link;
identify a user equipment identifier corresponding to the user
equipment detected in proximity to the femtocell using the OOB
communications link; and register/or the user equipment for hand-in
from a macrocell to the femtocell by communicating, from the
femtocell to a femtocell gateway, the user equipment identifier and
indicating OOB proximity detection of the user equipment at the
femtocell.
[0013] The communications management subsystem may be configured to
identify the user equipment identifier using a configuration to
receive a macro identifier associated with the user equipment
identifier over the OOB communications link. The communications
management subsystem may be configured to identify the user
equipment identifier using a configuration to receive an OOB
identifier associated with the user equipment identifier over the
OOB communications link. The communications management subsystem
may be configured to register the user equipment using a
configuration to transmit a registration message from the femtocell
to the femtocell gateway. The communications management subsystem
may be configured to register the user equipment using a
configuration to transmit an OOB indication message from the
femtocell to the femtocell gateway.
[0014] The communications management subsystem may be further
configured to utilize a user equipment mapping between a macro
identifier of the user equipment with a OOB identifier to determine
the user equipment identifier. The communications management
subsystem configured to detect the user equipment in proximity to
the femtocell may be configured to: page the user equipment over
the OOB communications link; and/or detect a response to the paging
from the user equipment over the OOB communications link. The
response may include a macro identifier and/or an OOB identifier of
the user equipment.
[0015] The communications management subsystem may be further
configured to: receive a handover request for the user equipment at
the femtocell from the femtocell gateway, the handover request
being configured to direct the user equipment to hand off active
communications with the macro network from the macrocell to the
femtocell. The handover request may be received subsequent to
registering the user equipment for hand-in from the macrocell to
the femtocell. The handover request may be received prior to
registering the user equipment for hand-in from the macrocell to
the femtocell. The communications management subsystem may be
configured to detect the user equipment by detecting the user
equipment in response to receiving the handover request. The
communications management subsystem may be configured to detect the
user equipment in response to receiving the handover request using
a configuration to detect the user equipment over the OOB
communications link utilizing an OOB identifier of the user
equipment. In some embodiments, a macro identifier of the user
equipment may be utilized.
[0016] In some embodiments, the communications management subsystem
may be further configured to detect a loss of the OOB
communications link between the user equipment and the femtocell.
The user equipment may be de-registered according to detecting the
loss of the OOB communications link. In some embodiments, the
communications management subsystem may be further configured to
transmit a handover response accepting the handover request as part
of registering the user equipment. In some embodiments, the
femtocell is one of multiple femtocells on a cellular network, each
femtocell having a first femtocell identifier according to which
the femtocell is non-uniquely addressable by the macro network and
a second femtocell identifier according to which the femtocell is
uniquely addressable by the femto gateway.
[0017] Some embodiments include a processor for
macrocell-to-femtocell hand-in. The processor may include a
communications management controller that may be configured to:
detect a user equipment in proximity to the femtocell using an
out-of-band (OOB) communications link; identify a user equipment
identifier corresponding to the user equipment detected in
proximity to the femtocell using the OOB communications link;
and/or register the user equipment for hand-in from a macrocell to
the femtocell by communicating, from the femtocell to a femtocell
gateway, the user equipment identifier and indicating OOB proximity
detection of the user equipment at the femtocell.
[0018] Some embodiments include computer program product for
macrocell-to-femtocell hand-in residing on a processor-readable
medium and including processor-readable instructions, which, when
executed, cause a processor to perform steps that may include:
detecting a user equipment in proximity to a femtocell using an
out-of-band (OOB) communications link; identifying a user equipment
identifier corresponding to the user equipment detected in
proximity to the femtocell using the OOB communications link;
and/or registering the user equipment for hand-in from a macrocell
to the femtocell by communicating, from the femtocell to a
femtocell gateway, the user equipment identifier and indicating OOB
proximity detection of the user equipment at the femtocell.
[0019] Some embodiments include a system for macrocell-to-femtocell
hand-in. The system may include: means for detecting a user
equipment in proximity to the femtocell using an out-of-band (OOB)
communications link; means for identifying a user equipment
identifier corresponding to the user equipment detected in
proximity to the femtocell using the OOB communications link;
and/or means for registering the user equipment for hand-in from a
macrocell to the femtocell by communicating, from the femtocell to
a femtocell gateway, the user equipment identifier and indicating
00B proximity detection of the user equipment at the femtocell.
[0020] Some embodiments include a method for macrocell-to-femtocell
hand-in. The method may include receiving, at a femtocell gateway
from a macro network, a handover request configured to direct a
user equipment to hand off active communications with the macro
network from a macrocell to a designated femtocell with a first
femtocell identifier. It may be determined, at the femtocell
gateway, whether any of multiple femtocells registered the user
equipment with the femtocell gateway prior to receiving the
handover request. The handover request may be communicated, from
the femtocell gateway, to the designated femtocell.
[0021] Determining, at the femtocell gateway, whether any of the
multiple femtocells registered the user equipment with the
femtocell gateway prior to receiving the handover request may
include determining a registering femtocell from the plurality of
femtocells that has registered the user equipment prior to
receiving the handover request; and/or determining that the
registering femtocell is the designated femtocell with the first
femtocell identifier. The method for macrocell-to-femtocell hand-in
may further include receiving an acknowledgement message from the
registering femtocell.
[0022] Determining, at the femtocell gateway, whether any of the
multiple femtocells registered the user equipment with the
femtocell gateway prior to receiving the relocation request may
include determining that none of the multiple femtocells registered
the user equipment prior to receiving the handover request. The
method may further include determining a set of candidate
femtocells from the multiple femtocells registered at the femto
gateway. The set of candidate femtocells may be identified by at
least the first femtocell identifier. Each of the set of candidate
femtocells may be directed to detect whether the user equipment is
in its proximity. An indication may be received from a successful
femtocell of the candidate femtocells that the user equipment is in
its proximity. It may be determined that the successful femtocell
is the designated femtocell. In some embodiments, the method may
further include monitoring an elapsed time subsequent to directing
the set of candidate femtocells to detect whether the user
equipment is in its proximity; and determining whether the
indication from one of the candidate femtocells that the user
equipment is in its proximity is received while the elapsed time is
within a predefined time limit.
[0023] Determining, at the femtocell gateway, whether any of the
multiple femtocells registered the user equipment prior to
receiving the handover request may include determining whether an
OOB proximity detection is received from any of the plurality of
femtocells prior to receiving the handover request. The OOB
proximity indication may include a macro identifier of the user
equipment.
[0024] Determining, at the femtocell gateway, whether any of the
multiple femtocells registered the user equipment prior to
receiving the handover request may include determining whether an
OOB proximity indication is received from any of the multiple
femtocells prior to receiving the handover request. The OOB
proximity indication may include an OOB identifier of the user
equipment. A macro identifier of the user equipment corresponding
to the OOB identifier of the user equipment may be determined.
[0025] The method of macrocell-to-femtocell hand-in may further
include determining whether the designated femtocell is uniquely
addressable by the femtocell gateway according to the first
femtocell identifier. Communicating, from the femtocell gateway,
the handover request to designated femtocell may utilize the first
femtocell identifier.
[0026] Determining, at the femtocell gateway, whether any of the
multiple femtocells registered the user equipment prior to
receiving the handover request may include determining whether two
or more femtocells of the multiple femtocells are addressable by
the femtocell gateway according to the first femtocell identifier.
Determining whether the designated femtocell is one of the two or
more femtocells addressable according to the first femtocell
identifier may utilize a second femtocell identifier.
[0027] In some embodiments, the method of macrocell-to-femtocell
hand-in may further include determining a set of candidate
femtocells from the multiple femtocells; and directing, using an
OOB hand-in cause value in the handover request, each of the set of
candidate femtocells to detect whether the user equipment is in its
proximity. The method may further include receiving an OOB accept
message from one of the candidate femtocells. The OOB accept
message may indicate that the one of the candidate femtocells
detects the user equipment in its proximity. The method may include
identifying one of the candidate cells associated with the OOB
accept message as the designated femtocell. In some embodiments,
the method may further receiving at least an OOB reject message
from one or more of the candidate femtocells or an error indication
message from one or more of the candidate femtocells and no OOB
accept messages; and/or transmitting to each of the candidate
femtocells a handover request with a normal cause value. The method
may further include receiving at least a blind accept or a blind
reject from one or more of the candidate femtocells; and/or
identifying one of the candidate femtocells associated with a blind
accept as the designated femtocell.
[0028] Some embodiments include a femtocell gateway that may
include a macro network interface subsystem configured to
communicate with a core node of a macro network and configured to
receive communications from the macro network. The femtocell
gateway may include a femtocell interface subsystem configured to
communicate with multiple femtocells. The femtocell gateway may
include a communications management subsystem, communicatively
coupled with the macro network interface subsystem and the
femtocell interface subsystem, and may be configured to: receive,
from the macro network, a handover request configured to direct a
user equipment to hand off active communications with the macro
network from a macrocell to a designated femtocell with a first
femtocell identifier; determine whether any of the multiple
femtocells registered the user equipment with the femtocell gateway
prior to receiving the handover request; and/or communicate the
handover request to designated femtocell.
[0029] To determine whether any of the multiple femtocells
registered the user equipment with the femtocell gateway prior to
receiving the handover request, the communications management
subsystem may be configured to: determine a registering femtocell
from the multiple femtocells that has registered the user equipment
prior to receiving the handover request; and/or determine that the
registering femtocell is the designated femtocell with the first
femtocell identifier. The communications management subsystem may
be further configured to: receive an acknowledgement message from
the registering femtocell.
[0030] To determine whether any of the multiple femtocells
registered the user equipment with the femtocell gateway prior to
receiving the handover request, the communications management
subsystem may be configured to: determine that none of the multiple
femtocells registered the user equipment prior to receiving the
handover request. The communications management subsystem may be
further configured to determine a set of candidate femtocells from
the multiple femtocells. The candidate femtocells may be identified
by at least the first femtocell identifier. Each of the candidate
femtocells may be directed to detect whether the user equipment is
in its proximity. An indication may be received from a successful
femtocell of the candidate femtocells that the user equipment is in
its proximity. It may be determined that the successful femtocell
is the designated femtocell. The communications management
subsystem may be further configured to: monitor an elapsed time
subsequent to directing the set of candidate femtocells to detect
whether the user equipment is in its proximity; and/or determine
whether the indication from one of the candidate femtocells that
the user equipment is in its proximity is received while the
elapsed time is within a predefined time limit.
[0031] To determine whether any of the multiple femtocells
registered the user equipment with the femtocell gateway prior to
receiving the handover request, the communications management
subsystem may be further configured to determine whether an OOB
proximity indication is received from any of the multiple
femtocells prior to receiving the handover request, wherein the OOB
proximity indication comprises a macro identifier of the user
equipment. To determine whether any of the multiple femtocells
registered the user equipment with the femtocell gateway prior to
receiving the handover request, the communications management
subsystem may be further configured to: determine whether an OOB
proximity detection is received from any of the multiple femtocells
prior to receiving the handover request, wherein the OOB proximity
indication comprises an OOB identifier of the user equipment;
and/or determine a macro identifier of the user equipment
corresponding to the OOB identifier of the user equipment.
[0032] In some embodiments, the communications management subsystem
may be further configured to: determine whether the designated
femtocell is uniquely addressable by the femtocell gateway
according to the first femtocell identifier. Communicating the
handover request to designated femtocell may utilize the first
femtocell identifier.
[0033] In some embodiments, the communications management subsystem
configured to determine whether any of the multiple femtocells
registered the user equipment prior to receiving the handover
request may include a configuration to: determine whether two or
more femtocells of the multiple femtocells are addressable by the
femtocell gateway according to the first femtocell identifier;
and/or determine whether the designated femtocell is one of the two
or more femtocells addressable according to the first femtocell
identifier utilizing a second femtocell identifier.
[0034] In some embodiments, the communications management subsystem
may be further configured to: determine a set of candidate
femtocells from the multiple femtocells; and direct, using an OOB
hand-in cause value in the handover request, each of the candidate
femtocells to detect whether the user equipment is in its
proximity. The communications management subsystem may be further
configured to: receive an OOB accept message from one of the
candidate femtocells, wherein the OOB accept message indicates that
the one of the candidate femtocells detects the user equipment in
its proximity; and/or identify the one of the candidate cells as
the designated femtocell. The communications management subsystem
may be further configured to: receive at least an OOB reject
message from one or more of the candidate femtocells or an error
indication message from one or more of the candidate femtocells and
no OOB accept messages; and transmit to each of the candidate
femtocells a handover request with a normal cause value. The
communications management subsystem may be further configured to:
receive at least a blind accept or a blind reject from one or more
of the candidate femtocells; and/or identify one of the candidate
femtocells associated with a blind accept as the designated
femtocell.
[0035] Some embodiments include a processor for
macrocell-to-femtocell hand-in in a femtocell gateway. The
processor may include a communications management controller
configured to: receive, from the macro network, a handover request
configured to direct a user equipment to hand off active
communications with the macro network from a macrocell to a
designated femtocell with a first femtocell identifier; determine
whether any of a plurality of femtocells registered the user
equipment with the femtocell gateway prior to receiving the
handover request; and/or communicate the handover request to the
designated femtocell.
[0036] Some embodiments include a computer program product for
macrocell-to-femtocell hand-in residing on a processor-readable
medium disposed at a femtocell gateway and including a
processor-readable instructions, which, when executed, cause a
processor to perform steps that may include receiving, from a macro
network, a handover request configured to direct a user equipment
to hand off active communications with the macro network from a
macrocell to a designated femtocell with a first femtocell
identifier; determining whether any of a plurality of femtocells
registered the user equipment with the femtocell gateway prior to
receiving the handover request; and/or communicating the handover
request to the designated femtocell.
[0037] Some embodiments include system for macrocell-to-femtocell
hand-in that may include: means for receiving, from a macro
network, a handover request configured to direct a user equipment
to hand off active communications with the macro network from a
macrocell to a designated femtocell with a first femtocell
identifier; means for determining whether any of a plurality of
femtocells registered the user equipment with the femtocell gateway
prior to receiving the handover request; and/or means for
communicating the handover request to the designated femtocell.
[0038] The foregoing has outlined rather broadly examples according
to disclosure in order that the detailed description that follows
may be better understood. Additional features will be described
hereinafter. The conception and specific examples disclosed may be
readily utilized as a basis for modifying or designing other
structures for carrying out the same purposes of the present
disclosure. Such equivalent constructions do not depart from the
spirit and scope of the appended claims. Features which are
believed to be characteristic of the concepts disclosed herein,
both as to their organization and method of operation, together
with associated advantages will be better understood from the
following description when considered in connection with the
accompanying figures. Each of the figures is provided for the
purpose of illustration and description only and not as a
definition of the limits of the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] A further understanding of the nature and advantages of
examples provided by the disclosure may be realized by reference to
the remaining portions of the specification and the drawings
wherein like reference numerals are used throughout the several
drawings to refer to similar components. In some instances, a
sub-label is associated with a reference numeral to denote one of
multiple similar components. When reference is made to a reference
numeral without specification to an existing sub-label, the
reference numeral refers to all such similar components.
[0040] FIG. 1 shows a block diagram of a wireless communications
system in accordance with various embodiments;
[0041] FIG. 2A shows a block diagram of a wireless communications
system that includes a femtocell in accordance with various
embodiments;
[0042] FIG. 2B shows a block diagram of a wireless communications
system that another femtocell in accordance with various
embodiments;
[0043] FIG. 3 shows a block diagram of an example of a processor
module for implementing functionality of a communications
management subsystem in accordance with various embodiments;
[0044] FIG. 4 shows a block diagram of an example of a mobile user
equipment in accordance with various embodiments;
[0045] FIG. 5 shows a simplified network diagram of a
communications system for facilitating active hand-in using a
femtocell in accordance with various embodiments;
[0046] FIG. 6A shows a block diagram of a wireless communications
system that includes a femtocell gateway in accordance with various
embodiments;
[0047] FIG. 6B shows a block diagram of another femtocell gateway
in accordance with various embodiments;
[0048] FIG. 7A shows a flow diagram of a method for handling user
equipment registration with a femtocell in accordance with various
embodiments;
[0049] FIG. 7B shows a flow diagram of a method for handling user
equipment registration with a femtocell using a Bluetooth radio for
out-of-band proximity detection in accordance with various
embodiments;
[0050] FIG. 8 shows a flow diagram of a method for handling active
hand-ins with a femtocell in accordance with various
embodiments;
[0051] FIG. 9 shows a call flow diagram illustrating an active
hand-in in accordance with various embodiments such as the methods
of FIGS. 9 and 10;
[0052] FIG. 10 shows a flow diagram of a method for handling
de-registration of user equipment with a femtocell in accordance
with various embodiments;
[0053] FIG. 11 shows a flow diagram of a method for implementing
certain active hand-in functionality without OOB proximity
detection in accordance with various embodiments;
[0054] FIG. 12 shows a flow diagram of a method for handling
femtocell-assisted active hand-in at a femtocell gateway in
accordance with various embodiments;
[0055] FIG. 13A shows a flow diagram of a method for handling
femtocell-assisted active hand-in at a femtocell gateway in
accordance with various embodiments;
[0056] FIG. 13B shows a flow diagram of a method for handling
femtocell-assisted active hand-in at a femtocell gateway with a
tiered approach in accordance with various embodiments;
[0057] FIGS. 14A and 14B show call flow diagrams illustrating an
active hand-in in accordance with various embodiments such the
methods of FIGS. 11, 12, and/or and 13;
[0058] FIG. 15A shows a call flow diagram of a method for handling
the receipt of handover requests when a "tiered" approach is used
and OOB detection is successful in accordance with various
embodiments; and
[0059] FIG. 15B shows a call flow diagram of a method for handling
the receipt of handover requests when the "tiered" approach is used
and OOB detection is unsuccessful in accordance with various
embodiments.
DETAILED DESCRIPTION
[0060] The following description generally relates to supporting
macrocell-to-femtocell hand-ins of active macro communications for
mobile devices. A femtocell may detect a mobile device in its
proximity (e.g., using an out-of-band link established by an
out-of-band radio integrated with the femtocell, which may be part
of a femto-proxy system). Having detected the mobile device in its
proximity, the femtocell may communicate an OOB proximity detection
or presence indication to pre-register the mobile device with a
femtocell gateway (or other type of interface gateway) disposed in
a core network in communication with the macro network. When the
femtocell gateway receives a handover request from the macro
network implicating the pre-registered mobile device, the femtocell
gateway may be able to reliably determine the appropriate femtocell
to use for the hand-in according to the OOB proximity detection.
Some embodiments also provide for registering the mobile device
after a handover request has occurred. In addition, some
embodiments may provide "tiered" approaches for handling the
receipt of handover requests.
[0061] The following description provides examples, and is not
limiting of the scope, applicability, or configuration set forth in
the claims. Changes may be made in the function and arrangement of
elements discussed without departing from the spirit and scope of
the disclosure. Various examples may omit, substitute, or add
various procedures or components as appropriate. For instance, the
methods described may be performed in an order different from that
described, and various operations may be added, omitted, or
combined. Also, features described with respect to certain examples
may be combined in other examples.
[0062] Referring first to FIG. 1, a block diagram illustrates an
example of a wireless communications system 100. The system 100
includes macrocell base stations 105, user equipments (UEs) 115, a
base station controller 120, femtocell 125, and a core network 130
(the controller 120 may be integrated into the core network 130).
The system 100 may support operation on multiple carriers (waveform
signals of different frequencies). Multi-carrier transmitters can
transmit modulated signals simultaneously on the multiple carriers.
Each modulated signal may be a Code Division Multiple Access (CDMA)
signal, Time Division Multiple Access (TDMA) signal, Frequency
Division Multiple Access (FDMA) signal, Orthogonal FDMA (OFDMA)
signal, Single-Carrier FDMA (SC-FDMA) signal, etc. Each modulated
signal may be sent on a different carrier and may carry control
information (e.g., pilot signals), overhead information, data, etc.
The system 100 may be a multi-carrier LTE network capable of
efficiently allocating network resources.
[0063] The UEs 115 may be any type of mobile station, mobile
device, access terminal, subscriber unit, or user equipment. The
UEs 115 may include cellular phones and wireless communications
devices, but may also include personal digital assistants (PDAs),
smartphones, other handheld devices, netbooks, notebook computers,
etc. Thus, the term user equipment (UE) should be interpreted
broadly hereinafter, including the claims, to include any type of
wireless or mobile communications device.
[0064] The macrocell base stations 105 may wirelessly communicate
with the UEs 115 via a base station antenna. The macrocell base
stations 105 may be configured to communicate with the UEs 115
under the control of the controller 120 via multiple carriers. Each
of the base station 105 sites can provide communication coverage
for a respective geographic area. In some embodiments, macrocell
base stations 105 may be referred to as a Node B. The coverage area
for each macrocell base station 105 here is identified as 110-a,
110-b, or 110-c. The coverage area for a base station may be
divided into sectors (not shown, but making up only a portion of
the coverage area). The system 100 may include base stations 105 of
different types (e.g., macro, micro, and/or pico base stations). As
used herein, the term "cell" may refer to 1) a sector, or 2) a site
(e.g., a base station 105). Thus, the term "macrocell" may refer to
1) a macrocell sector, 2) a macrocell base station (e.g., macrocell
base station 105), and/or 3) a macrocell controller. Thus, the term
"femtocell" may refer to 1) a femtocell sector, or 2) a femtocell
base station (e.g., femtocell access point).
[0065] For the discussion below, the UEs 115 operate on (are
"camped on") a macro or similar network facilitated by multiple
macrocell base stations 105. Each macrocell base station 105 may
cover a relatively large geographic area (e.g., hundreds of meters
to several kilometers in radius) and may allow unrestricted access
by terminals with service subscription. A portion of the UEs 115
may also be registered to operate (or otherwise allowed to operate)
in femtocell coverage area 110-d (e.g., communicating with
femtocell 125, which may be referred to as a femtocell access point
(FAP) in some cases), within the coverage area of a macrocell
110-a. As a UE 115 approaches a femtocell, there may be need for
novel mechanisms for the UE 115 to recognize the presence of the
femtocell 125 so that the UE 115 may migrate to the femtocell 125
from the macrocell base station 105.
[0066] Strategic deployment of femtocells may be used to mitigate
mobile device power consumption, as mobile devices typically
operate using an internal power supply, such as a small battery, to
facilitate highly mobile operation. Femtocells may be used to
offload traffic and reduce spectrum usage at a macrocell.
Femtocells may also be utilized to provide service within areas
which might not otherwise experience adequate or even any service
(e.g., due to capacity limitations, bandwidth limitations, signal
fading, signal shadowing, etc.), thereby allowing mobile devices to
reduce searching times, to reduce transmit power, to reduce
transmit times, etc. A femtocell 125 may provide service within a
relatively small service area (e.g., within a house or building).
Accordingly, a UE 115 is typically disposed near a femtocell 110-d
when being served, often allowing the UE 115 to communicate with
reduced transmission power.
[0067] By way of example, the femtocell may be implemented as a
Home Node B ("HNB") or Home eNode B (HeNB), and located in a user
premises, such as a residence, an office building, etc. Femtocell
125 will be used hereinafter generically to describe any femtocell
access point, and should not be interpreted as limiting. The
femtocell 125 location may be chosen for maximum coverage (e.g., in
a centralized location), to allow access to a global positioning
satellite (GPS) signal (e.g., near a window), or in other
locations. A set of UEs 115 may be registered on (e.g., on a
whitelist of) a single femtocell 125 that provides coverage over
substantially an entire user premises. The "home" femtocell 125
provides the UE 115 with access to communication services via a
connection to the macrocell communications network. As used herein,
the macrocell communications network is assumed to be a wireless
wide-area network (WWAN). As such, terms like "macrocell network"
and "WWAN network" are interchangeable. Similar techniques may be
applied to other types of network environments, femtocell coverage
topologies, etc., without departing from the scope of the
disclosure or claims.
[0068] Systems, methods, devices, and computer program products are
described to identify target femtocells to facilitate
femto-assisted active hand-ins. In example configurations, the
femtocell 125 may be integrated with one or more OOB transceivers.
The femtocell 125 may transmit or receive OOB discovery signals
(e.g., Bluetooth page or inquiry signals) to or from a UE 115 to
facilitate the exchange of femtocell and device information. The
femtocell 125 may, of course, also be configured to connect with a
UE 115 via in-band signals. The femtocell 125 may detect the UE 115
in proximity to the femtocell 125 using an OOB communications link.
The femtocell 125 may identify an identifier of the UE 115. The
femtocell 125 may register the UE 115 for hand-in from the
macrocell base station 105 for example, to the femtocell 125. The
registration process may include communicating, from the femtocell
125 to a femtocell gateway (not shown), the UE identifier and
indicating OOB proximity detection of the UE 115 to the femtocell
125.
[0069] As used herein, the term "frequency range" may be used to
refer to the frequency spectrum allocated to a particular macrocell
or femtocell, or for OOB signaling. A macrocell frequency range may
be a first frequency channel within a set of frequencies allocated
to WWAN communications, and a femtocell frequency range may be a
second frequency channel within the set of frequencies allocated to
WWAN communications. The macrocell frequency range and the
femtocell frequency range may the same, or different (therefore,
there may be an intra-frequency or inter-frequency search for a
femtocell). Additional macrocell frequency ranges may occupy other
frequency channels within the set of frequencies allocated to WWAN
communications.
[0070] As used herein, "out-of-band," or "OOB," includes any type
of communications that are out-of-band with respect to the
macrocell or femtocell communications network. For example, a
femtocell 125 and/or the UE 115 may be configured to operate using
Bluetooth (e.g., class 1, class 1.5, and/or class 2), ZigBee (e.g.,
according to the IEEE 802.15.4-2003 wireless standard), near field
communication (NFC), WiFi, an ultra-wideband (UWB) link, and/or any
other useful type of communications out of the macrocell network
band.
[0071] OOB integration with the femtocell 125 may provide a number
of features. For example, the OOB signaling may allow for reduced
interference, lower power femtocell registration, macrocell
offloading, and so on. Further, the integration of OOB
functionality with the femtocell 125 may allow the UEs 115
associated with the femtocell 125 to also be part of an OOB
piconet. The piconet may facilitate enhanced HNB functionality,
other communications services, power management functionality,
and/or other features to the UEs 115. These and other features will
be further appreciated from the description below.
[0072] FIG. 2A shows a block diagram of a wireless communications
system 200-a that includes OOB capabilities. This system 200-a may
be an example of aspects of the system 100 depicted in FIG. 1. The
femtocell 125-a may include an OOB frequency module 240-a, an
in-band frequency module 230-a, and/or a communications management
subsystem 250. The in-band frequency module 230-a may be a femto
Node B and/or radio network controller, as described with reference
to FIG. 1. The femtocell 125-a also may include antennas 205, a
transceiver module 210, memory 215, and a processor module 225,
which each may be in communication, directly or indirectly, with
each other (e.g., over one or more buses). The transceiver module
210 may be configured to communicate bi-directionally, via the
antennas 205, with the UEs 115. The transceiver module 210 (and/or
other components of the femtocell 125-a) may also be configured to
communicate bi-directionally with a macro communications network
100-a (e.g., a WWAN). For example, the transceiver module 210 may
be configured to communicate with the macro communications network
100-a via a backhaul network. The macro communications network
100-a may be the communications system 100 of FIG. 1.
[0073] The memory 215 may include random access memory (RAM) and
read-only memory (ROM). In some embodiments, the memory 215
includes (or is in communication with) a data store 217 configured
to store UE mappings 219. As described more fully below, these UE
mappings 219 may be used to facilitate certain femtocell-assisted
hand-in functionality. Typically the UE mappings 219 map a
identifier of each UE 115 (e.g., the International Mobile
Subscriber Identity (IMSI) associated with the UE's 115 SIM card)
with an OOB identifier corresponding to the UE's 115 OOB radio
(e.g., the UE's 115 Bluetooth address). In certain embodiments,
further mappings are maintained for each UE 115 by the UE mappings
219 including, for example, a public long code mask.
[0074] The memory 215 may also store computer-readable,
computer-executable software code 220 containing instructions that
are configured to, when executed, cause the processor module 225 to
perform various functions described herein (e.g., call processing,
database management, message routing, etc.). Alternatively, the
software 220 may not be directly executable by the processor module
225 but be configured to cause the computer, e.g., when compiled
and executed, to perform functions described herein.
[0075] The processor module 225 may include an intelligent hardware
device, e.g., a central processing unit (CPU) such as those made by
Intel.RTM. Corporation or AMD.RTM., a microcontroller, an
application specific integrated circuit (ASIC), etc. The processor
module 225 may include a speech encoder (not shown) configured to
receive audio via a microphone, convert the audio into packets
(e.g., 30 ms in length) representative of the received audio,
provide the audio packets to the transceiver module 210, and
provide indications of whether a user is speaking Alternatively, an
encoder may only provide packets to the transceiver module 210,
with the provision or withholding/suppression of the packet itself
providing the indication of whether a user is speaking
[0076] The transceiver module 210 may include a modem configured to
modulate the packets and provide the modulated packets to the
antennas 205 for transmission, and to demodulate packets received
from the antennas 205. While some examples of the femtocell 125-a
may include a single antenna 205, the femtocell 125-a preferably
includes multiple antennas 205 for multiple links. For example, one
or more links may be used to support macro communications with the
UEs 115. Also, one or more out-of-band links may be supported by
the same antenna 205 or different antennas 205.
[0077] Notably, the femtocell 125-a may be configured to provide
both in-band frequency module 230-a and OOB frequency module 240-a
functionality. For example, when the UE 115 approaches the
femtocell coverage area, the UE's 115 OOB radio may begin searching
for the OOB frequency module 240-a. In some cases, the OOB
frequency module 240-a may page the UE's OOB radio. Upon discovery,
the UE 115 may have a high level of confidence that it is in
proximity to the femtocell coverage area, and a scan for the
in-band frequency module 230-a may commence. Similarly, the OOB
frequency module 240-a may be utilized by the femtocell 125-a to
determine that a UE 115 is in proximity to the femtocell 125-a.
[0078] The scan for the in-band frequency module 230-a may be
implemented in different ways. For example, due to the OOB
frequency module 240-a discovery by the UE's 115 OOB radio, both
the UE 115 and the femtocell 125-a may be aware of each other's
proximity. The UE 115 may scan for the in-band frequency module
230-a. Alternatively, the in-band frequency module 230-a may poll
for the UE 115 (e.g., individually, or as part of a round-robin
polling of all registered UEs 115), and the UE 115 may listen for
the poll. When the scan for the in-band frequency module 230-a is
successful, the UE 115 may attach to the in-band frequency module
230-a.
[0079] When the UE 115 is in the femtocell coverage area and is
linked to the in-band frequency module 230-a through a
communication link, the UE 115 may be in communication with the
macro communications network 100-a via the in-band frequency module
230-a. As described above, the UE 115 may also be a slave of a
piconet for which the OOB frequency module 240-a acts as the
master. For example, the piconet may operate using Bluetooth and
may include Bluetooth communications links facilitated by a
Bluetooth radio (e.g., implemented as part of the transceiver
module 210) in the in-band frequency module 230-a.
[0080] Examples of the in-band frequency module 230-a have various
configurations of base station or wireless access point equipment.
As used herein, the in-band frequency module 230-a may be a device
that communicates with various terminals (e.g., client devices (UEs
115, etc.), proximity agent devices, etc.) and may also be referred
to as, and include some or all the functionality of, a base
station, a Node B, Home Node B, and/or other similar devices.
Although referred to herein as the in-band frequency module 230-a,
the concepts herein are applicable to access point configurations
other than femtocell configuration (e.g., picocells, microcells,
etc.). Examples of the in-band frequency module 230-a utilize
communication frequencies and protocols native to a corresponding
cellular network (e.g., the macro communications network 100-a, or
a portion thereof) to facilitate communication within a femtocell
coverage area associated with the in-band frequency module 230-a
(e.g., to provide improved coverage of an area, to provide
increased capacity, to provide increased bandwidth, etc.).
[0081] The in-band frequency module 230-a may be in communication
with other interfaces not explicitly shown in FIG. 2A. For example,
the in-band frequency module 230-a may be in communication with a
native cellular interface as part of the transceiver module 210
(e.g., a specialized transceiver utilizing cellular network
communication techniques that may consume relatively large amounts
of power in operation) for communicating with various appropriately
configured devices, such as the UE 115, through a native cellular
wireless link (e.g., an "in-band" communication link) Such a
communication interface may operate according to various
communication standards, including but not limited to wideband code
division multiple access (W-CDMA), CDMA2000, global system for
mobile telecommunication (GSM), worldwide interoperability for
microwave access (WiMax), and wireless LAN (WLAN). Also or
alternatively, the in-band frequency module 230-a may be in
communication with one or more backend network interfaces as part
of the transceiver module 210 (e.g., a backhaul interface providing
communication via the Internet, a packet switched network, a
switched network, a radio network, a control network, a wired link,
and/or the like) for communicating with various devices or other
networks.
[0082] As described above, the in-band frequency module 230-a may
further be in communication with one or more OOB interfaces as part
of the transceiver module 210 and/or the OOB frequency module
240-a. For example, the OOB interfaces may include transceivers
that consume relatively low amounts of power in operation and/or
may cause less interference in the in-band spectrum with respect to
the in-band transceivers. Such an OOB interface may be utilized
according to embodiments to provide low power wireless
communications with respect to various appropriately configured
devices, such as an OOB radio of the UE 115. The OOB interface may,
for example, provide a Bluetooth link, an ultra-wideband (UWB)
link, an IEEE 802.11 (WLAN) link, etc.
[0083] The terms "high power" and "low power" as used herein are
relative terms and do not imply a particular level of power
consumption. Accordingly, OOB devices (e.g OOB frequency module
240-a) may simply consume less power than native cellular interface
(e.g., for macro WWAN communications) for a given time of
operation. In some implementations, OOB interfaces also provide
relatively lower bandwidth communications, relatively shorter range
communication, and/or consume relatively lower power in comparison
to the macro communications interfaces. There is no limitation that
the OOB devices and interfaces be low power, short range, and/or
low bandwidth. Devices may use any suitable out-of-band link,
whether wireless or otherwise, such as IEEE 802.11, Bluetooth,
PEANUT, UWB, ZigBee, an IP tunnel, a wired link, etc. Moreover,
devices may utilize virtual OOB links, such as through use of IP
based mechanisms over a wireless wide area network (WWAN) link
(e.g., IP tunnel over a WWAN link) that acts as a virtual OOB
link.
[0084] OOB frequency module 240-a may provide various types of OOB
functionality and may be implemented in various ways. An OOB
frequency module 240-a may have any of various configurations, such
as a stand-alone processor-based system, a processor-based system
integrated with a host device (e.g., access point, gateway, router,
switch, repeater, hub, concentrator, etc.), etc. For example, the
OOB frequency module 240-a may include various types of interfaces
for facilitating various types of communications. In some
embodiments, the OOB frequency module 240-a may be referred to as a
femto-proxy module.
[0085] Some OOB frequency module 240-a include one or more OOB
interfaces as part of the transceiver module 210 (e.g., a
transceiver that may consume relatively low amounts of power in
operation and/or may cause less interference than in the in-band
spectrum) for communicating with other appropriately configured
devices (e.g., a UE 115) for providing interference mitigation
and/or femtocell selection herein through a wireless link. One
example of a suitable communication interface is a
Bluetooth-compliant transceiver that uses a time-division duplex
(TDD) scheme.
[0086] OOB frequency module 240-a may also include one or more
backend network interfaces as part of the transceiver module 210
(e.g., packet switched network interface, switched network
interface, radio network interface, control network interface, a
wired link, and/or the like) for communicating with various devices
or networks. An OOB frequency module 240-a that is integrated
within a host device, such as with in-band frequency module 230-a,
may utilize an internal bus or other such communication interface
in the alternative to a backend network interface to provide
communications between the OOB frequency module 240-a and other
devices, if desired. Additionally or alternatively, other
interfaces, such as OOB interfaces, native cellular interfaces,
etc., may be utilized to provide communication between the OOB
frequency module 240-a and the in-band frequency module 230-a
and/or other devices or networks.
[0087] Various communications functions (e.g., including those of
the in-band frequency module 230-a and/or the OOB frequency module
240-a) may be managed using the communications management subsystem
250. For example, the communications management subsystem 250 may
at least partially handle communications with the macro (e.g.,
WWAN) network, one or more OOB networks (e.g., piconets, UE 115 OOB
radios, other femto-proxies, OOB beacons, etc.), one or more other
femtocells (e.g., in-band frequency module 230-a), UEs 115, etc.
For example, the communications management subsystem 250 may be a
component of the femtocell 125-a in communication with some or all
of the other components of the femtocell 125-a via a bus.
[0088] Various other architectures are possible other than those
illustrated by FIG. 2A. The in-band frequency module 230-a and/or
the OOB frequency module 240-a may or may not be collocated,
integrated into a single device, configured to share components,
etc. For example, the femtocell 125-a of FIG. 2A has an integrated
in-band frequency module 230-a and OOB frequency module 240-a that
at least partially share components, including the antennas 205,
the transceiver module 210, the memory 215, and the processor
module 225.
[0089] The components of the femtocell 125-a may, individually or
collectively, be implemented, in whole or in part, with
instructions embodied in a memory, formatted to be executed by one
or more general or application-specific processors. They may also
be implemented with one or more application specific integrated
circuits (ASICs) adapted to perform some or all of the applicable
functions in hardware. Alternatively, the functions may be
performed by one or more other processing units (or cores), on one
or more integrated circuits. In other embodiments, other types of
integrated circuits may be used (e.g., Structured/Platform ASICs,
Field Programmable Gate Arrays (FPGAs), and other Semi-Custom ICs),
which may be programmed in any manner known in the art.
[0090] FIG. 2B shows a block diagram of a wireless communications
system 200-b that includes an architecture of a femtocell 125-b
that is different from the architecture shown in FIG. 2A. Similar
to the femtocell 125-a of FIG. 2A, the femtocell 125-b includes an
OOB frequency module 240-b and an in-band frequency module 230-b.
Unlike the system 125-a of FIG. 2A, however, each of the OOB
frequency module 240-b and the in-band frequency module 230-b has
its own antenna 205, transceiver module 210, memory 215, and
processor module 225. Both transceiver modules 210 are configured
to communicate bi-directionally, via their respective antennas 205,
with UEs 115. The transceiver module 210-1 of the in-band frequency
module 230-b is illustrated in bi-directional communication with
the macro communications network 100-b (e.g., typically over a
backhaul network).
[0091] For the sake of illustration, the femtocell 125-b is shown
without a separate communications management subsystem 250. In some
configurations, a communications management subsystem 250 is
provided in both the OOB frequency module 240-b and the in-band
frequency module 230-b. In other configurations, the communications
management subsystem 250 is implemented as part of the OOB
frequency module 240-b. In still other configurations,
functionality of the communications management subsystem 250 is
implemented as a computer program product (e.g., stored as software
220 in memory 215) of one or both of the OOB frequency module 240-b
and the in-band frequency module 230-b.
[0092] The components of the femtocell 125-b may, individually or
collectively, be implemented, in whole or in part, with
instructions embodied in a memory, formatted to be executed by one
or more general or application-specific processors. They may also
be implemented with one or more application specific integrated
circuits (ASICs) adapted to perform some or all of the applicable
functions in hardware. Alternatively, the functions may be
performed by one or more other processing units (or cores), on one
or more integrated circuits. In other embodiments, other types of
integrated circuits may be used (e.g., Structured/Platform ASICs,
Field Programmable Gate Arrays (FPGAs), and other Semi-Custom ICs),
which may be programmed in any manner known in the art.
[0093] In yet other configurations, some or all of the
functionality of the communications management subsystem 250 of
system 200-a may implemented as a component of the processor module
225. FIG. 3 shows a block diagram 300 of a processor module 225-a
for implementing functionality of the communications management
subsystem 250. The processor module 225-a may include a WWAN
communications controller 310 and a user equipment controller 320.
The processor module 225-a may be in communication (e.g., as
illustrated in FIGS. 2A and 2B) with the OOB frequency module 240
and/or the in-band frequency module 230. The WWAN communications
controller 310 may be configured to receive a WWAN communication
(e.g., a page) for a designated UE 115. The user equipment
controller 320 may determine how to handle the communication,
including affecting operation of the OOB frequency module 240
and/or the in-band frequency module 230.
[0094] Both the in-band frequency module 230-a of FIG. 2A and the
in-band frequency module 230-b of FIG. 2B are illustrated as
providing a communications link only to the macro communications
network 100-a. However, the in-band frequency module 230 may
provide communications functionality via many different types of
networks and/or topologies. For example, the in-band frequency
module 230 may provide a wireless interface for a cellular
telephone network, a cellular data network, a local area network
(LAN), a metropolitan area network (MAN), a wide area network
(WAN), the public switched telephone network (PSTN), the Internet,
etc.
[0095] As described above, the femtocell 125 may be configured to
communicate with client devices, including the UEs 115. FIG. 4
shows a block diagram 400 of mobile user equipment (UE) 115-a for
use with the femtocell 125 of FIGS. 2A and/or 2B in the context of
the communications systems and networks of FIGS. 1-3. The UE 115-a
may have any of various configurations, such as personal computers
(e.g., laptop computers, net book computers, tablet computers,
etc.), cellular telephones, PDAs, digital video recorders (DVRs),
internet appliances, gaming consoles, e-readers, etc. For the
purpose of clarity, the UE 115-a is assumed to be provided in a
mobile configuration, having an internal power supply (not shown),
such as a small battery, to facilitate mobile operation.
[0096] The UE 115-a may include antennas 445, an in-band
transceiver module 410, an OOB transceiver module 405, memory 415,
and a processor module 425, which each may be in communication,
directly or indirectly, with each other (e.g., via one or more
buses). The transceiver modules 405, 410 may be configured to
communicate bi-directionally, via the antennas 445 with femtocells
and macrocells. For example, the in-band transceiver module 410 may
be configured to communicate bi-directionally with macrocell base
stations 105 of a macrocell of FIG. 1, and with the femtocell 125
of FIG. 1, 2A, or 2B. The OOB transceiver module 405 may be
configured to communicate bi-directionally with the femtocell 125
of FIG. 1, 2A, or 2B. Each transceiver module 405, 410 may include
a modem configured to modulate the packets and provide the
modulated packets to the antennas 445 for transmission, and to
demodulate packets received from the antennas 445. While the UE
115-a may include a single antenna, the UE 115-a will typically
include multiple antennas 445 for multiple links.
[0097] As generally referenced above, the OOB transceiver module
405 may be configured to communicate with a femtocell over one or
more OOB communication links as described in more detail below. The
OOB transceiver module 405 at the mobile device 115-a may include a
Bluetooth transceiver for example.
[0098] The memory 415 may include random access memory (RAM) and
read-only memory (ROM). The memory 415 may store computer-readable,
computer-executable software code 420 containing instructions that
are configured to, when executed, cause the processor module 425 to
perform various functions described herein (e.g., call processing,
database management, message routing, etc.). Alternatively, the
software 420 may not be directly executable by the processor module
425 but be configured to cause the computer (e.g., when compiled
and executed) to perform functions described herein.
[0099] The processor module 425 may include an intelligent hardware
device, e.g., a central processing unit (CPU) such as those made by
Intel.RTM. Corporation or AMD.RTM., a microcontroller, an
application specific integrated circuit (ASIC), etc. The processor
module 325 may include a speech encoder (not shown) configured to
receive audio via a microphone, convert the audio into packets
(e.g., 30 ms in length) representative of the received audio,
provide the audio packets to the in-band transceiver module 410,
and provide indications of whether a user is speaking
Alternatively, an encoder may only provide packets to the in-band
transceiver module 410, with the provision or
withholding/suppression of the packet itself providing the
indication of whether a user is speaking
[0100] According to the architecture of FIG. 4, the UE 115-a
further includes a communications management module 440. The
communications management module 440 may manage communications with
a macrocell, femtocell, other UEs 115 (e.g., acting as a master of
a secondary piconet), etc. By way of example, the communications
management module 440 may be a component of the UE 115-a in
communication with some or all of the other components of the UE
115-a via a bus. Alternatively, functionality of the communications
management module 440 may be implemented as a component of a
transceiver module 405, 410, as a computer program product, and/or
as one or more controller elements of the processor module 425.
[0101] Some components of the UE 115-a may, individually or
collectively, be implemented, in whole or in part, with
instructions embodied in a memory, formatted to be executed by one
or more general or application-specific processors. They may also
be implemented with one or more application specific integrated
circuits (ASICs) adapted to perform some or all of the applicable
functions in hardware. Alternatively, the functions may be
performed by one or more other processing units (or cores), on one
or more integrated circuits. In other embodiments, other types of
integrated circuits may be used (e.g., Structured/Platform ASICs,
Field Programmable Gate Arrays (FPGAs), and other Semi-Custom ICs),
which may be programmed in any manner known in the art.
[0102] In many cases, it is desirable to support active hand-in
from a macrocell (e.g., macrocell base stations 105 of FIG. 1) to
the femtocell 125 and/or active hand-out from the femtocell 125 to
the macrocell base station 105 using handovers to provide seamless
voice and data service to active users (active UEs 115). Active
handouts can be relatively simple to implement and are supported by
most operators with legacy macro networks 100 and UEs 115. However,
active hand-in may be challenging and may not typically be
supported by operators.
[0103] For example, as a UE 115 moves during the course of active
communications with the macro network 100 (e.g., during a voice
call, an active data transfer, etc.), a determination may be made
that a handover is needed (e.g., the current macrocell base station
105 signal may become weak). The need for a handover may be
determined according to measurement reports sent by the active UE
115. Notably, the phrase "measurement report" may be generally
associated with 3GPP networks, but is intended herein to include
any similar types of measurement reporting in any similar type of
network (e.g., including "PSMMs," or pilot strength measurements,
in 3GPP2 networks).
[0104] The measurement reports may include a measurement of the
strength of the pilot observed by the UE 115 and the forward link
cell identifier of the target cell. The cell identifier may be any
identifier used by the macro network 100 to identify a particular
cell. For example, the cell identifier may be a "PSC" (primary
scrambling code) in a 3GPP network, a "PN offset" in a 3GPP2
network, etc. On a typical macro network 100, enough cell
identifiers (e.g., PSC) may be available to substantially ensure
that, given the geographical distribution of the macrocell base
stations 105, each macrocell base station 105 can effectively be
uniquely identified by its cell identifier (e.g., by a Radio
Network controller (RNC) 120 in the macro network 100, a Serving
GPRS Support Node (SGSN) in the core of the network, etc.).
[0105] While macrocell base stations 105 may effectively be
uniquely identified by the macro network 100, there are typically
not enough remaining cell identifiers to uniquely identify all
femtocells, such as femtocell 125, and in particular, the in-band
frequency modules 230 added to the network. For example, a typical
macro network 100 may have 512 PSC values available for assignment
to all the cells in its network. PN offsets may be reused on
different carriers, in different geographic regions, etc. to extend
the number of cells that can effectively be identified without
confusion. However, only a small portion of the PSC values may be
available for use by the femtocells 125, through their in-band
frequency modules 230 (i.e., other than the values reserved for use
by macrocell base stations 105), and the number and density of
femtocells 125 may be relatively large in some areas. For example,
only a small number of PSC values must be reused among possibly
hundreds of femtocells 125 per macro sector.
[0106] When a handover is required for an active UE 115 to a
macrocell base station 105 (as a handover from another macrocell
base station 105 or as a hand-out from a femtocell 125), the cell
identifier provided in the measurement report may be sufficient to
reliably determine the appropriate macrocell base station 105 for
hand-off. The active communication may be handed off to the correct
target cell without ambiguity. However, when a handover may be
required for an active UE 115 to a femtocell 125 (as a hand-in from
a macrocell base station 105), the same cell identifier provided in
the measurement report may be shared by multiple femtocells 125 in
the same macro sector. As such, the cell identifier alone may be
insufficient to reliably determine the appropriate femtocells 125
for hand-in in all cases. For example, the UE 115 may be near its
femtocell 125, and it may be desirable to hand-in to that femtocell
125, but another femtocell 125 in the macro sector may be
associated with the same cell identifier.
[0107] In some newer networks, additional identifiers are available
that may mitigate or solve this issue. For example, in UMTS
networks, cells may be upgraded to broadcast system information
(SI), location information, and/or other information that may make
identification of a particular femtocell 125 based only on its cell
identifier(s) more unique and reliable. Upgraded UEs 115 can
exploit new cell identifier(s), for example, by decoding the system
information of neighboring cells and reporting the identifiers in
measurement reports during active communications. The controllers
(which may include macro radio network controls (RNC) 120 and/or
Serving GPRS Support Node (SGSN) 550, shown below in FIG. 5) can
then include the SI (e.g. CELL_ID, C) in the handover messages to
uniquely identify the target femtocell 125 (e.g., to the femtocell
gateway). This technique may only be available for communications
between upgraded networks and upgraded UEs 115. For operators who
do not want to upgrade the air interface, this technique may not be
available. Likewise for operators who do want to upgrade their
networks (e.g. RNC 120 and SGSN 650 shown below in FIG. 6A) to
forward the SI to the femtocell gateway, this technique may not be
available.
[0108] Operators of legacy networks (including those desiring to
communicate with legacy UEs 115) may address this difficulty with
active hand-in in different ways. Some typical networks may not
support active hand-in at all. In the event that the hand-in may be
the only way to maintain the active communications with the UE 115,
the active communications may simply be lost (e.g., a call may be
dropped when signals from macrocell base station 105 are lost, even
when the UE 115 is otherwise in the femtocell coverage area).
[0109] According to at least one technique for addressing the
difficulty with active hand-in in legacy networks, some operators
may implement blind handover. For example, when the measurement
report includes a cell identifier that is shared by multiple
femtocells 125 in the same macro sector, the network may blindly
select any of the femtocells 125 having that cell identifier for
the hand-in. If blind selection results in hand-in to an
appropriate femtocell 125, the hand-in may be successful. However,
if blind selection results in hand-in to an inappropriate femtocell
125 (e.g., one that is out of range of the UE 115, one for which
the UE 115 is not authorized to attach, etc.), the active
communications may be lost.
[0110] It will now be appreciated that operators of legacy systems
may be unable to reliably support active hand-ins to femtocells 125
using existing techniques. Embodiments include novel techniques for
supporting active hand-ins for legacy networks and/or for legacy
UEs 115. Turning to FIG. 5, a simplified network diagram is shown
of a communications system 500 for facilitating active hand-in.
[0111] The communications system 500 may include a macro network
100, a user local network 510, and a core network 530. The core
network 530 may include, among other things, a femtocell gateway
540 and/or a SGSN 550. The femtocell gateway 540 may be in
communication with a number of femtocells 125 (only one femtocell
125 is shown for clarity), and the SGSN 550 is in communication
with multiple macrocell base stations 105 via one or more macro
RNCs 120 (only one macrocell base station 105 is show for clarity).
The femtocell 125 is in communication through in-band frequency
module 230 with the macro network 100 via core network 530
elements, such that cellular communications may be facilitated
through the femtocell 125 using functionality of the femtocell
gateway 540 and/or SGSN 550.
[0112] A UE 115 in active communications with the macrocell base
station 105 (over a macro communications link 560-b) may approach a
coverage area of the femtocell 125. As described above, the macro
network 100 (e.g., the macro RNC 120) may determine that a handover
is needed based on a measurement report from the UE 115. The
measurement report may identify the target femtocell 125 by its
cell identifier (e.g., its PSC). A handover request may then be
sent by the SGSN 550 to the target femtocell gateway 540 for
identifying an appropriate femtocell 125 for the hand-in.
[0113] As discussed, particularly where multiple femtocells 125
share a cell identifier, it may be difficult or impossible for the
femtocell gateway 540 to reliably determine the appropriate target
femtocell 125 for hand-in using the cell identifier alone. Some
embodiments may exploit features of femtocell 125. As shown, the
user local network 510 includes the in-band frequency module 230
functionality integrated with OOB functionality of an OOB frequency
module 240 as part of a femtocell 125. This OOB functionality may
be facilitated over an OOB communications link 570 that can be
established between the UE 115 and the OOB frequency module 240.
This in-band functionality may be facilitated over an in-band
communications link 550-a that can be established between the UE
115 and the in-band frequency module 230. The in-band
communications link 550-a may be established, for example, when a
hand-in occurs from macrocell 105 to femtocell 125.
[0114] While many different types of out-of-band communications may
be used to facilitate functionality described here (e.g., as
discussed above), the discussion below focuses on Bluetooth as
facilitating the OOB communications of these embodiments. Other
embodiments may utilize other types of out-of-band communications.
Bluetooth may provide certain features. One feature is that
Bluetooth radios may be integrated into many UEs 115, so that the
Bluetooth functionality can be exploited for many users without
modifying their existing UEs 115. Another feature is that the
tolerable path loss between two "Class 1.5" Bluetooth devices may
be comparable or even higher than between a femtocell 125 and a UE
115. In any given environment, this higher tolerable path loss may
translate to higher effective range (e.g., facilitating femtocell
125 discovery, handover, and/or interference mitigation, as
described herein).
[0115] Yet another feature of Bluetooth is that the Bluetooth
address (BD_ADDR) can provide a unique, 48-bit address used to
identify each Bluetooth enabled device. The Bluetooth address may
be used when a device communicates with another device, and is
divided into a 24-bit LAP (Lower Address Part), a 16-bit NAP
(Non-significant Address Part), and an 8-bit UAP (Upper Address
Part). The LAP may be assigned by a manufacturer and may be unique
for each Bluetooth device, while UAP and NAP may be part of an
Organizationally Unique Identifier (OUI). Using the Bluetooth
address, each Bluetooth adapter in any device may be identified
according to a globally unique value.
[0116] As described more fully below, embodiments may operate in
the context of a system, like the communications system 500 of FIG.
5, to support active hand-ins with minimal or no change to legacy
macro networks 100 and/or to legacy UEs 115. One set of such
embodiments uses modifications to UEs 115 and the femtocell gateway
540 to facilitate active hand-in. In particular, an OOB identifier
of the femtocell 125 may be detected by the UE 115 and communicated
as part of the measurement report to facilitate identification of
the target femtocell 125 by the femtocell gateway 540.
[0117] Each of the UE 115 and the femtocell 125 (through OOB
frequency module 240, for example) may have a unique Bluetooth
device address (BD_ADDR) that may be used for paging the other
device (e.g., UE 115 pages the femtocell 125 or the femtocell 125
pages the UE 115). It is understood that the BD_ADDR of the other
device may be known by the paging device. Notably, the same or
similar techniques may be used for other types of out-of-band
addressing. For example, the devices may know each other's WiFi MAC
address, etc. The UE 115 may then assist the macro network 100 in
effecting the active hand-in.
[0118] In some embodiments, after an OOB communications link 570 is
established with the OOB frequency module 240 of the femtocell 125,
the UE 115 can communicate a cell identifier (e.g., PSC) and the
OOB identifier (e.g., Bluetooth device address) of the target
femtocell 125 to the SGSN 550 as part of its measurement report.
The femtocell gateway 540 may maintain a mapping between the cell
identifier and the OOB identifier, which can then be used to
uniquely identify the target femtocell 125 for active hand-in.
[0119] One technique may involve upgrades at the UE 115
"air-interface" (i.e., new messages or modifications of existing
messages are involved). Also, proper communication of new UE 115
messaging may involve changes to the macro RNCs 120, the SGSN 550,
the femtocell gateway 540, and the femtocell 125 (and in
particular, the in-band frequency module 230 of the femtocell 125).
These changes to the legacy macro network 100 may largely be
software upgrades (rather than hardware upgrades), but operators
may still be reluctant to implement the changes.
[0120] Another set of embodiments supports active hand-ins for both
macro networks 100 and UEs 115, which may be legacy macro networks
100 and/or legacy UEs 115 in some cases. In particular, changes to
the femtocell 125 and/or the femtocell gateway 540 may allow for
femtocell 125 assisted active hand-in. Embodiments of femtocell 125
assisted hand-in may be implemented without changes to the
air-interface, the macro RNC 120, or the SGSN 550. Femtocell 125
assisted hand-in may exploit registration by the femtocell 125 of
UEs 115 at the femtocell gateway 540 (e.g., using OOB proximity
detection to effectively pre-register the UE 115 with the femtocell
gateway 540). When a handover directive is received at the
femtocell gateway 540 implicating a UE 115, registration of the UE
115 can be used by the femtocell gateway 540 to help determine the
appropriate target femtocell 125 for hand-in.
[0121] As described above with reference to FIG. 2A, embodiments of
the femtocell 125 may maintain UE mappings 219. Typically, the UE
mappings 219 map a macro identifier of each UE 115 (e.g., the
International Mobile Subscriber Identity (IMSI), Mobile Equipment
Identifier (MEID), Electronic Serial Number (ESN), etc.) with an
OOB identifier corresponding to the UE's 115 OOB radio (e.g.,
Bluetooth device address, WiFi MAC address, etc.). When the
femtocell 125 is a restricted access femtocell, the UE mappings 219
may be maintained only for authorized users. For example, an access
control list may be maintained at the femtocell 125 that includes
or is associated with the UE mappings 219.
[0122] Notably, there may various ways to establish the UE mappings
219. According to one exemplary technique, the UE 115 calls a
particular number, which may automatically trigger an OOB pairing
(e.g., a Bluetooth pairing) between the UE 115 and the femtocell
125. Thus, the mapping between the UE macro identifier and OOB
identifier may be established. According to another exemplary
technique, a user manually enters the UE's 115 macro identifier
(e.g., IMSI) and OOB identifier (e.g., BD_ADDR) into a user
interface at the femtocell 125. According to yet another exemplary
technique, a user enters the mapping information via a portal
(e.g., a web page), and the femtocell 125 downloads the information
(e.g., or the femtocell 125 includes a web server and the portal
directly addresses femtocell 125). In yet another exemplary
technique, the OOB identifier of the UE can be entered into the
portal by using a sniffer, an OOB-enabled device that wirelessly
obtains the OOB identifier and reports it to the portal.
[0123] Active hand-in functionality described herein may involve
use of a femtocell 125 having an in-band frequency module 230
integrated with an OOB frequency module 240. As illustrated in FIG.
5, and as described in a number of exemplary configurations above,
the OOB frequency module 240 includes an OOB device (e.g., an OOB
radio) that is communicatively coupled with the in-band frequency
module 230. For example, the in-band frequency module 230 and the
OOB frequency module 240 may be physically integrated into a single
housing or assembly (e.g., and in communication over a bus or some
other internal connection), or the OOB frequency module 240 may be
separately housed and may be in communication with the in-band
frequency module 230 using a wired or wireless connection.
Typically, the OOB frequency module 240 is located close enough to
the in-band frequency module 230 so that proximity detection by the
OOB frequency module 240 indicates proximity also to the in-band
frequency module 230.
[0124] In some other configurations, the OOB frequency module 240
is logically, rather than physically, integrated with the in-band
frequency module 230 (e.g., the components can otherwise be
logically associated with each other by the network). For example,
even having the OOB frequency module 240 physically separated from
the in-band frequency module 230, the components may be part of a
common subnet so that proximity detection by the OOB frequency
module 240 can be associated with proximity to the in-band
frequency module.
[0125] The configuration described in FIG. 5 is intended only to be
illustrative, and not limiting. Other configurations are possible
for providing the same or similar types of integrative
functionality between OOB frequency module 240 and in-frequency
module 230. For example, many configurations may allow OOB
proximity detection to be used to facilitate reliable active
hand-in to a particular femtocell 125, according to various
embodiments.
[0126] To facilitate femtocell 125 assisted hand-in, femtocells
125, like the one described in FIG. 2A for example, may interact
with embodiments of femtocell gateway 540, such as those described
in FIG. 6A and FIG. 6B. FIG. 6A shows a block diagram of a wireless
communications system 600-a that includes a femtocell gateway
540-a. The femtocell gateway 540-a may include a communications
management subsystem 610, a femto interface subsystem 630, and/or a
macro interface subsystem 640. The femtocell gateway 540-a also may
include memory 615 and a processor module 625. All the components
of the femtocell gateway 540-a may be in communication with each
other directly or indirectly (e.g., over one or more buses).
[0127] For the sake of context and clarity, the femto interface
subsystem 630 is shown in communication with femtocell 125 (which
includes in-band frequency module 230 and OOB frequency module
240), and the macro interface subsystem 640 is shown in
communication with macrocell base station 105 (via an SGSN 550
and/or one or more macro RNCs 120). Various communications
functions, including those involved in facilitating femtocell 125
assisted hand-in are implemented and/or managed using the
communications management subsystem 610. For example, the
communications management subsystem 610 may at least partially
handle communications with macro network elements using
functionality of the macro interface subsystem 640 and may at least
partially handle communications with femtocell 125 using
functionality of the femto interface subsystem 630. For example,
the communications management subsystem 610 may be a component of
the femtocell gateway 540-a in communication with some or all of
the other components of the femtocell gateway 540 via a bus.
[0128] The memory 615 may include random access memory (RAM) and
read-only memory (ROM). In some embodiments, the memory 615 is
configured to maintain registration-related information. As
described more fully below, the registration-related information
may include identifier mappings for femtocells 125, UEs 115, etc.,
as well as registration messages, flags, etc.
[0129] The memory 615 may also store computer-readable,
computer-executable software code 620 containing instructions that
are configured to, when executed, cause the processor module 625 to
perform various functions described herein (e.g., call processing,
database management, message routing, etc.). Alternatively, the
software 620 may not be directly executable by the processor module
625 but be configured to cause the computer, e.g., when compiled
and executed, to perform functions described herein.
[0130] The processor module 625 may include an intelligent hardware
device, e.g., a central processing unit (CPU) such as those made by
Intel.RTM. Corporation or AMD.RTM., a microcontroller, an
application specific integrated circuit (ASIC), etc. Embodiments of
the processor module 625 may be configured to facilitate
functionality, such as timer functionality. Further, embodiments of
the processor module 625 include or facilitate some or all of the
functionality of the communications management subsystem 610, the
femto interface subsystem 630, or the macro interface subsystem
640.
[0131] For example, FIG. 6B shows a block diagram of a wireless
communications system 600-b that includes a femtocell gateway 540-b
that is an alternate configuration of the femtocell gateway 540-a
of FIG. 6A. As with the femtocell gateway 540-a of FIG. 6A, the
femtocell gateway 540-b of FIG. 6B may include a femto interface
subsystem 630, a macro interface subsystem 640, memory 615, and/or
a processor module 625, which may all be in communication with each
other directly or indirectly (e.g., over one or more buses). Unlike
the femtocell gateway 540-a of FIG. 6A, the femtocell gateway 540-b
of FIG. 6B may include communications management controller 610.
Embodiments of the communications management controller 610 may be
implemented as part of the processor module 625 to provide
substantially the same functionality as that of the communications
management subsystem 610 shown in FIG. 6A.
[0132] As discussed above, embodiments of femtocell gateway 540,
such as those described in FIGS. 6A and 6B, can interact with
femtocells 125, like the one described in FIG. 2A, to facilitate
femtocell 125 assisted hand-in. For example, when a UE 115
approaches a femtocell 125, the femtocell 125 may detect the UE 115
in its proximity using an OOB link (e.g., Bluetooth paging
procedure) or vice versa. In addition to or as part of the OOB
detection procedure, the femtocell 125 may determine whether the UE
115 is an authorized user. For example, the femtocell 125 may check
an access control list to determine whether the UE 115 is
authorized to access macro communications services via the
femtocell 125.
[0133] Having discovered each other (and the femtocell 125 having
validated the UE 115 as an authorized user), the femtocell 125 may
register the UE 115 with the femtocell gateway 540. For example,
the femtocell 125 may maintain a UE mapping 219 between the UE's
115 OOB identifier (e.g., the Bluetooth device address,) detected
during the detection procedure and a macro identifier of the UE
115, like the UE's 115 IMSI. The femtocell 125 may register the UE
115 with the femtocell gateway 540 according to the UE's 115
identifier(s).
[0134] In some embodiments, the OOB radio range (e.g., the edge of
Bluetooth coverage) may be greater than the femtocell 125 coverage
range (for example, the range of the in-band frequency module 230),
such that the detection and registration of the UE 115 may be
performed before the UE 115 detects the femtocell 125. Thus, in
many cases, a, OOB proximity detection or indication may be
communicated by the femtocell 125 to the femtocell gateway 540 for
the UE 115 before any handover has been triggered by a measurement
report of the UE 115 (i.e., the UE 115 may effectively be
"pre-registered" upon receipt of any handover request implicating
the UE 115).
[0135] Notably, various types of registration or pre-registration
may be available in the macro network 100 and/or femtocell 125
context. As used herein, "registration" and "pre-registration" can
intend to refer to the existing UE registration in macro networks
(and the communication of this message between the femtocell 125
and femtocell gateway 540 may be triggered by the OOB proximity
detection). In another embodiment, the registration refers to a
message carrying an OOB proximity detection specifically to
register a UE 115 with an femtocell gateway 540. When a handover is
triggered and a relocation request is received at the femtocell
gateway 540 (e.g., from the SGSN 650), the femtocell gateway 540
may be able to correlate the UE registration with the handover
request (e.g., according to the UE's 115 macro identifier). With
this information, the femtocell gateway 540 can uniquely identify
the appropriate target femtocell 125 and reliably proceed with the
hand-in. If the existing UE 115 registration message in macro
network is used for indicating the OOB proximity to femtocell
gateway 540, the femtocell gateway 540 may create an entry for the
UE 115 and the registering femtocell 125 in a registration database
as it would for regular UE registrations not indicating OOB
proximity. Later on, when a handover is triggered and a relocation
request is received at the femtocell gateway 540 (e.g., from the
SGSN 650), the femtocell gateway 540 may use the entry in the
database to correlate the UE 115 with registration in the database
with the handover request (e.g., according to the UE's 115 macro
identifier). With this information, the femtocell gateway 540 can
uniquely identify the appropriate target femtocell 125 and reliably
proceed with the hand-in.
[0136] In some cases, the femtocell gateway 540 communicates the
handover request to the femtocell 125 with a flag indicating that
femtocell gateway 540 thinks that the UE 115 is in proximity of the
femtocell 125 based on the femtocell's 125 prior registration with
the UE's 115 macro identifier (e.g., IMSI). Having received the
flag, the femtocell 125 may try to detect the UE 115 again (e.g.,
over an OOB channel using the OOB frequency module 240). If the UE
115 is no longer in the femtocell's 125 proximity, the femtocell
125 can reject the handover request from the femtocell gateway 540.
Further certain types of de-registration techniques may be used, as
described below.
[0137] According to one de-registration technique, a UE 115 is
explicitly deregistered by communicating an OOB absence indication
to the femtocell gateway 540. For example, the OOB frequency module
240 and/or the in-band frequency module 230 may detect link loss
with the UE 115 and send a de-registration request to the femtocell
gateway 540 in the form of an OOB absence indication. According to
another de-registration technique, a UE 115 may be de-registered if
a certain amount of time elapses after registration without
receiving a corresponding handover request. According to yet
another de-registration technique, a UE 115 may be explicitly or
implicitly de-registered upon acknowledgement of handover to the
target femtocell 125.
[0138] In some embodiments, registration is only performed for
active UEs 115. In one illustrative scenario, as described above,
registration is based on detection over an OOB communication link
and subsequent communication to the femtocell gateway 540 of an OOB
proximity detection or indication. In this scenario, the femtocell
125 may not know whether the UE 115 is in WWAN idle state or active
state (e.g., in a voice call). For idle handover, the femtocell's
125 pre-registration with the femtocell gateway 540 with the UE's
115 macro identifier (e.g., IMSI) is ignored. For example, implicit
de-registration may occur if a handover request message does not
arrive at femtocell gateway 540 prior to a timeout.
[0139] In another illustrative scenario, a handover request message
arrives at the femtocell gateway 540 (e.g., as a relocation request
message from the core network 130 of FIG. 1) implicating a UE 115.
Even if the UE 115 has been pre-registered, the femtocell gateway
540 may send a handover request to the femtocell 125 with a flag
indicating that the femtocell gateway 540 believes the UE 115 is in
proximity of that specific femtocell 125 based on the
pre-registration. In some embodiments, the femtocell 125 again
tries to detect the UE 115 over the OOB communication link. If it
fails, the femtocell 125 may reject the handover request; if it
succeeds, the femtocell 125 may accept the handover request.
[0140] If the registration request is received at the femtocell
gateway 540 after a corresponding handover request implicating the
UE 115 is received at the femtocell gateway 540, the femtocell
gateway 540 may handle the hand-in in various ways, as described
more fully below (e.g., with reference to the call flow diagram of
FIGS. 13-14). For example, even when the registration request is
received after a corresponding handover request, techniques
described herein may be used to help facilitate active hand-in.
Alternatively, there may be no hand-in, or techniques described
above may be used, like blind hand-in, etc.
[0141] It may be appreciated that the femtocell 125 assisted
hand-in techniques described herein provide certain features. One
feature may be that the techniques may be used to reliably
determine an appropriate target femtocell 125 for active hand-in.
Another feature is that pre-registration through communication of
OOB proximity detection or indication may reduce or eliminate
latencies relating to the blind hand-off technique. Yet another
feature is that core network signaling (e.g., from measurement
request and response) may be reduced. And another feature is that
no changes may be needed in the UE 115, the air interface, or the
legacy infrastructure. The techniques may be implemented with
changes only to the femtocell 125 and/or the femtocell gateway
540.
[0142] Embodiments of femtocell 125 assisted hand-in techniques are
described below with reference to methods of FIGS. 7-14. Turning
first to FIG. 7A, a flow diagram is shown of a method 700-a for
macrocell-to-femtocell hand-in in accordance with various
embodiments. The method 700-a may, for example, be performed by the
femtocell 125 of FIG. 1, 2A, 2B, 5, 6A, or 6B. The method 700-a may
begin at block 705 by detecting a UE 115 in proximity to a
femtocell 125 using an OOB communications link. The femtocell 125
may be communicatively coupled with a macro network 100 via a
macrocell base station 105. For example, the UE 115 may be camped
on the macrocell base station 125 and may or may not be in active
cellular communications. The femtocell 125 may include includes an
OOB frequency module 240 and an in-band frequency module 230. The
in-band frequency module 230 may include an HNB. The femtocell 125,
through the in-band frequency module 230, may be communicatively
coupled with the macro network 100 via a femtocell gateway 540. In
some embodiments, the femtocell gateway 540 may be a HNB
gateway.
[0143] At block 710, an identifier of UE 115 on the macro network
100 may be identified or determined by the femtocell 125 using the
OOB communications link. For example, as part of detecting the UE
115 at block 705, an OOB identifier corresponding to the UE 115
(e.g., the BD_ADDR) may be detected using the OOB frequency module
240 over an OOB communications link. In some embodiments, a macro
identifier (e.g., IMSI) associated with the UE 115 may be
identified. As discussed above, the femtocell 125 may maintain UE
mappings 219 between a corresponding OOB identifier and identifier
for a particular UE 115.
[0144] In some embodiments, a determination is made as to whether
the UE 115 is authorized to access the macro network 100 via the
femtocell 125. For example, the femtocell 125 may maintain an
access control list (e.g., a "white list") with UEs 115 authorized
to attach to the femtocell 125 (e.g., authorized to access macro
communications services via the femtocell 125). If it is determined
that the UE 115 is not authorized to access the macro network 100
via the femtocell 125, the method 700-a may abort. For example, the
method 700-a may ignore the UE 115. In some embodiments, the
femtocell gateway 540 may determine whether the UE 115 is
authorized to access the macro network 100 via the femtocell 125.
If it is determined that the UE 115 is authorized to access the
macro network 100 via the femtocell 125, the femtocell 125 may
proceed with registering the UE 115 as described below.
[0145] At block 715, the UE 115 is registered for hand-in from the
macrocell base station 105 to the femtocell 125. This may be done
by communicating, from the femtocell 125 to the femtocell gateway
540, the user equipment identifier. In addition, the registering of
the UE 115 may indicate OOB proximity detection of the UE 115 with
respect to the femtocell 125. For example, the femtocell 125 may
communicate at least the UE's 115 macro identifier to the femtocell
gateway 540 as part of a registration message. As discussed above,
the OOB range may be greater than (e.g., or at least substantially
the same as) the femtocell range, such that the blocks of the
method 700-a (e.g., from the proximity detection at block 705 to
communication of the registration method at block 715) may, in some
cases, occur before the UE 115 enters the femtocell range. In this
way, the registration may occur before the UE's 115 measurement
report may indicate the femtocell 125 and before any handover to
the femtocell 125 is determined by the macro network 100.
[0146] Registering the UE 115 for hand-in the macrocell 105 to the
femtocell 125 may include transmitting a registration message from
the femtocell 125 to the femtocell gateway 540. Registering the UE
115 for hand-in from the macrocell 105 to the femtocell 125 may
include transmitting an OOB indication message from the femtocell
125 to the femtocell gateway 540. Some embodiments may utilize a UE
mapping between a macro identifier of the UE 115 with the OOB
identifier to determine the user equipment identifier.
[0147] As described above with reference to FIG. 5, various
configurations may use different types of OOB proximity detection
to facilitate registration (e.g., pre- and/or post-registration
using OOB proximity detection). For example, portions of the method
700-a may be different, depending on whether the OOB proximity
detection was being performed using a configuration like the one
shown in FIG. 5 (e.g., using a Bluetooth radio as an OOB frequency
module 240 physically integrated with the femtocell 125). For the
sake of added clarity, an example scenario is described in FIG.
7B.
[0148] Turning first to FIG. 7B, a flow diagram is shown of a
method 700-b for macrocell-to-femtocell hand-in utilizing UE 115
registration at a femtocell gateway 540 using a femtocell 125 in
accordance with various embodiments. The method 700-b may, for
example, be performed by the femtocell 125 of FIG. 1, 2A, 2B, 5,
6A, or 6B. Method 700-b may be performed in the context of a
Bluetooth radio being used as an OOB frequency module 240
physically integrated with a femtocell 125, for example. For the
sake of added clarity, reference numerals from FIG. 7A are used
with the addition of a lower-case "a" to indicate a possible
illustrative implementation of the corresponding block from FIG. 7A
in the context of FIG. 7B. Accordingly, the method 700-b begins
with block 705-a in which a Bluetooth radio, configured as an OOB
frequency module 240 integrated with a femtocell 125 is used to
detect a UE 115 in proximity to the femtocell 125.
[0149] Block 705-a includes blocks 720 and 725. At block 725, a
Bluetooth radio (i.e., OOB frequency module 240) periodically pages
the UE 115 to see whether the UE 115 is in its proximity. As used
herein, "periodically" is intended broadly to convey types of
signaling that are non-continuous. For example, periodically may
include signaling (e.g., paging) at predefined intervals, according
to particular thresholds, etc. At block 725, the Bluetooth radio of
the femtocell detects a response from the UE 115 over a Bluetooth
link. More generally, the femtocell may page the UE 115 over an OOB
communications link and then detect a response to the paging from
the UE 115 over the OOB communications link. The response may
include an OOB identifier of the UE 115. In some embodiments, the
response may include a macro identifier of the UE 115.
[0150] Having received the response from the UE 115, the femtocell
125 may be aware that the UE 115 is in proximity, and the femtocell
125 may know the Bluetooth device address (e.g., BD_ADDR) of the UE
115. As described above, the Bluetooth device address may
effectively provide a unique out-of-band identifier for the UE 115.
In some configurations, the femtocell 125 makes further
determinations. For example, as discussed above, the femtocell 125
may determine whether the UE 115 is authorized to access the macro
network 100 via the femtocell 125, through the in-band frequency
module 230, for example.
[0151] At block 710-a, a macro identifier identifying the UE 115 on
the macro network 100 (e.g., the IMSI) may be determined. For
example, UE mappings 219 between a corresponding OOB identifier and
macro identifier for a particular UE 115 may be maintained by the
femtocell 125, such that the femtocell 125 may determine the macro
identifier of the UE 115 from its corresponding Bluetooth device
address. Alternatively, the mappings may be maintained at the
femtocell gateway 540.
[0152] At block 715-a, the UE 115 may be registered for hand-in
from the macrocell base station 105 to the target femtocell 125. In
particular, the femtocell 125 may communicate an OOB proximity
detection or OOB presence indication to the femtocell gateway 540
with an identifier of the UE 115 to register the UE 115 with the
femtocell gateway 540. In some configurations, in which the UE
mappings are maintained at the femtocell 125, the OOB proximity
detection or indiction may be communicated to the femtocell gateway
540 with the UE's 115 macro identifier (e.g., and OOB identifier,
in some configurations). In other configurations, in which the UE
mappings are maintained at the femtocell gateway 540, the OOB
proximity detection or indication may be communicated to the
femtocell gateway 540 with the UE's 115 OOB identifier, and the
femtocell gateway 540 may then determine the mapping to the
corresponding macro identifier.
[0153] Using Bluetooth for proximity may provide a number of
features. For example, Bluetooth may allow for relatively low-power
paging, range that may be similar to that of the femtocell coverage
area, etc. Further, many UEs 115 may already be equipped with
Bluetooth radios, such that the techniques may be implemented with
little or no changes to the UEs 115. However, certain limitations
may manifest in some configurations. For example, the femtocell 125
may need to be integrated with the Bluetooth radio, and certain
types of provisioning may be difficult. Further, when using an
open-femtocell (e.g., no access control list) or enterprise-type
configuration, it may be difficult or inefficient to page the large
number of Bluetooth addresses corresponding to all UEs 115 that may
be in proximity. Some embodiments may utilize other forms of OOB
communication to address these issues, or utilize other methods
discussed herein.
[0154] FIG. 8 shows a flow diagram of a method 800 for handling
active hand-ins with a femtocell in accordance with various
embodiments. The method 800 may, for example, be performed by the
femtocell 125 of FIG. 1, 2A, 2B, 5, 6A, or 6B. The method 800 is
shown in the context of block 715 of FIG. 7A or FIG. 7B for added
clarity. For the sake of illustration, the method 800 is described
for a UE 115 that was registered by the femtocell 125 with the
femtocell gateway 540, for example, according to the method 700-a
of FIG. 7A.
[0155] Accordingly, the method 800 may begin at block 805 by
receiving a handover request for a pre-registered UE 115 (a UE 115
for which OOB proximity detection has previously been communicated
to the femtocell gateway 540) at the femtocell 125 from the
femtocell gateway 540. In these cases, the handover request may be
received subsequent to registered the UE 115 from hand-in from the
macrocell to the femtocell. In some embodiments, the femtocell 125
maintains an awareness of its registration of the UE 115, such that
it is aware of the proximity of the UE 115 when the handover
request is received. In other embodiments, the handover request
includes a flag or other indication to the femtocell 125 that the
implicated UE 115 is believed to be in the femtocell's 125
proximity (e.g., that the UE 115 has been pre-registered by the
femtocell 125 by communicating an OOB proximity detection to the
femtocell gateway 540).
[0156] At block 810, an acknowledgement message may be communicated
from the femtocell 125 to the femtocell gateway 540 in response to
receiving the handover request. The messaging between the femtocell
125 and the femtocell gateway 540 may be implemented across one or
more networks. For example, the acknowledgement message may be
communicated from the femtocell 125 to a secure gateway at the edge
of a core network over an Internet Protocol Security (IPSec)
tunnel, from the secure gateway to an IP Multimedia Subsystem (IMS)
network in the core network, and from the IMS network to the
femtocell gateway 540 in the core network.
[0157] At block 815, the pre-registered UE 115 is directed to hand
in active communications from its currently connected (source)
macrocell 105 to the target femtocell 125. Notably, the UE 115 may
not typically receive any handover direction from the femtocell
125. Rather, the femtocell 125 may acknowledge the handover request
to indicate that it is an appropriate handover target, and macro
network 100 elements (e.g., the source macrocell 105) ultimately
may communicate the handover directive to the UE 115.
[0158] Merely by way of example, a call flow diagram 900
illustrating an active hand-in according to the methods 700 and 800
of FIGS. 7 and 8 is shown in FIG. 9. The call flow diagram 900
shows communications between a UE 115, a currently connected
(source) macrocell 105, RNC 120, a source SGSN 650, a target
femtocell gateway 540, and two potential target femtocells 125-a
and 125-b. For the sake of avoiding excess detail, the signaling
between source macrocell 105 in communication with a macro RNC 120,
is not shown. It is assumed for the sake of the call flow diagram
900 that the potential target femtocells 125 have a common cell
identifier (e.g., they have the same PSC). As such, it may be
necessary to reliably determine the appropriate one of the
potential target femtocells 125 to ensure a successful active
hand-in.
[0159] The call flow diagram 900 begins at block 904 with the UE
115 currently engaged in an active macro communications, like a
voice call or a data call, that may be facilitated by the source
SGSN 650 via the source macrocell 105 and/or RNC 120. At some time,
the UE 115 moves into proximity of the OOB frequency module 240
associated with a first of the potential target femtocell 125-a
(e.g., the OOB frequency module 240 and an in-band frequency module
230 may integrated into the femtocell 125-a). At block 908, the OOB
frequency module 240 may detect the UE 115 in its proximity (e.g.,
as in block 705 of FIG. 7A). At block 912, the first potential
target femtocell 125-a may send an OOB proximity detection or
indication (e.g., a registration request) to the target femtocell
gateway 540 to pre-register the UE 115 (e.g., according to block
715 of FIG. 7A). At block 914, the target femtocell gateway 540 may
respond with a registration acceptance acknowledging the reception
of the registration request from the target femtocell 125-a, and
then may confirm that an entry for the UE 115 and registering
femtocell 125-a have been created in the registration database.
[0160] At some time thereafter, the UE 115 may move into the
femtocell coverage area of the femtocell 125, detect the femtocell
125, and send a measurement report to the source macrocell 105
and/or RNC 120 at block 916. The measurement report may include the
pilot strength of the femtocell 125 as observed by the UE 115 and
the PSC of the femtocell 125. The source macrocell 105 and/or RNC
120 may determine that a handover is required according to the
measurement report and may communicate a relocation required
message to the source SGSN 650 at block 920. At block 924, the
relocation required message may be communicated (e.g., as a
relocation request message over the core network) from the source
SGSN 650 to the target femtocell gateway 540.
[0161] Having received a relocation request, the target femtocell
gateway 240 may now determine which potential target femtocell 125
is the correct target for the hand-in. For example, the handover
request may include the IMSI of the UE 115 and the PSC of the
target femtocell 125. However, in this exemplary case, two
potential target femtocells 125 may have the same PSC, such that
one cannot be uniquely identified by the PSC alone. Using
traditional techniques, as described above, the handover request
may be addressed, for example, by ignoring the hand-in, by blindly
selecting one of the potential target femtocells 125, etc. However,
having received the OOB proximity indication or UE registration
message at block 912, the target femtocell gateway 540 may reliably
select the first potential target femtocell 125-a as the correct
target femtocell 125 for the hand-in.
[0162] At block 928, the target femtocell gateway 540 may send the
handover request to the first target femtocell 125-a. The first
target femtocell 125-a may respond to the target femtocell gateway
540 with a handover response carrying an "accept" message at block
932. The handover may then be communicated to the UE 115 via the
core network and/or the macro network 100. Notably, while referred
to generically herein in some instances as "handover requests" for
the sake of simplicity, each related message may, in fact, be of a
different form and/or purpose. For example, as illustrated, a
handover response may be communicated from the target femtocell
gateway 540 to the source SGSN 650 as a relocation response message
at block 936; a relocation command may be communicated from the
source SGSN 650 to the source macrocell 105 and/or RNC 120 at block
940; and/or a relocation command may be communicated from the
source macrocell 105 and/or RNC 120 to the UE 115 as a physical
channel configuration message at block 944.
[0163] At block 948, the UE 115 may communicate an acknowledgement
message, the physical channel reconfiguration message to the source
macrocell 105 and/or RNC 120. At block 952, the UE 115 may attempt
to detect and synchronize with the first potential femtocell 125-a;
and, at block 956, the UE 115 may communicate a handover complete
message to the first potential target femtocell 125-a; and the
first potential target femtocell 125-a may communicate the handover
complete message to the target femtocell gateway 540 at block 960.
Although not shown in the figure, the handover complete message may
be relayed to the source macrocell 105 and/or RNC 120 so that the
radio link set-up for the UE 115 can be deleted. Having completed
the hand-in, the UE's 115 active macro communications (e.g., the
voice call) continue at block 964 facilitated by the appropriately
identified target femtocell 125 (i.e., previously the first
potential target femtocell 125-a) instead of by the source
macrocell 125 and/or RNC 120.
[0164] It is worth noting that the call flow diagram 900 is
intended to show one example of a exemplary call flow and is
simplified in many ways to add clarity. For example, while a
"handover request" is discussed in a number of blocks, it will be
appreciated that each element may communicate the message in
similar or different forms with similar or different information
included. As such, the call flow diagram 900 should not be
construed as limiting the scope of the disclosure or claims.
[0165] It is further worth noting that it may be necessary or
desirable to de-register UEs 115 in certain cases. For example,
suppose that a UE 115 is registered by a first femtocell 125-a.
Later, the UE 115 may move into proximity of a second femtocell
125-b that may have the same PSC of the first femtocell 125-a, but
may be located well out of range of the first femtocell 125-a
(e.g., miles away). The UE 115 may send a measurement report with
the shared PSC, triggering a handover request. At this block, the
femtocell gateway 540 may have to use one or more techniques to
determine that handover to the second femtocell 125-b, rather than
to the first femtocell 125-a, is desired. Otherwise, registration
by the first femtocell 125-a may cause the femtocell gateway 540 to
attempt a hand-in of the active communications of the UE 115 from
its current macrocell 105 to the first femtocell 125-a, even though
the UE 115 is well out of range of the first femtocell 125, which
may cause undesirable results (e.g., an active voice call may be
dropped). Registration time stamps, de-registration, and/or other
techniques described herein may be used to address this issue, as
described more fully below.
[0166] FIG. 10 shows a flow diagram of a method 1000 for handling
de-registration of UEs in accordance with various embodiments. The
method 1000 may, for example, be performed by the femtocell 125 of
FIG. 1, 2A, 2B, 5, 6A, or 6B. The method 1000 is shown in the
context of block 715 of FIG. 7A for added clarity. For the sake of
illustration, the method 1000 is described for a UE 115 that was
registered by the femtocell 125 with the femtocell gateway 540, for
example, according to the method 700-a of FIG. 7A.
[0167] The method 1000 may begin at block 1005 by determining
whether an OOB communications link between the OOB frequency module
240 and the registered UE 115 has been lost. As described above
(e.g., with reference to block 705 of FIG. 7A), an OOB
communications link may be established between the UE 115 and an
OOB frequency module 240 associated with the target femtocell 125.
If the OOB communications link is lost (e.g., at all, for a
predetermined minimum duration, etc.), this may indicate that the
UE 115 is no longer in proximity to the femtocell 125.
[0168] If it is determined at block 1005 that the OOB
communications link has been lost (e.g., since registration of the
UE 115), the UE 115 may be de-registered at the femtocell gateway
540 by the femocell 125 at block 1010. If it is determined at block
1005 that the OOB communications link has not been lost, a further
determination may be made at block 1015 as to whether a handover
request has been received for the registered UE 115 at the
femtocell 125. If a handover request has not been received, the
method 1000 may iterate through blocks 1005 and 1015 until either
the OOB communications link is determined to be lost at block 1005
or the handover request is received at block 1015. If a handover
request has been received for the registered UE 115 at the
femtocell 125, the registered UE 115 may be directed to hand-in
(e.g., according to block 815 of FIG. 8).
[0169] Certain embodiments may handle de-registration in other
ways. For example, in one configuration, the method 1000 may
explicitly de-register the UE 115 after completing the hand-in
(e.g., successfully and/or unsuccessfully). Notably, however, it
may be useful to maintain the registration (i.e., not de-register
the UE 115) even after hand-in to provide the network with
knowledge about the proximity of the UE 115 and/or other types of
information that can be gained from the registration.
[0170] According to another configuration, when the UE 115 is
registered at the femtocell gateway 540, the registration is
associated with a timestamp. For example, the registering femtocell
125 may communicate an OOB proximity detection that includes the
UE's 115 macro identifier (e.g., or OOB identifier) and a
timestamp. If another femtocell 125 subsequently sends a
registration request to the femtocell gateway 540 for the same UE
115, the new registration request may include a later timestamp.
The femtocell gateway 540 may then consider any prior registration
request to be invalid, and facilitate handover to the
later-requesting femtocell 125. For example, the UE 115 may
implicitly be de-registered from prior-requesting femtocell 125
upon receiving a subsequent registration request at the femtocell
gateway 540.
[0171] According to still another configuration, timer-based
de-registration is implemented. For example, upon registering the
UE 115, the femtocell 125 may begin a timer (e.g., or otherwise
begin tracking elapsed time). A certain timeframe (e.g., one
minute) may be determined after which de-registration is
appropriate. For example, setting the timeframe too small may cause
the femtocell 125 to have to re-register the UE 115 inefficiently,
while setting the timeframe too large may allow the UE 115 to enter
coverage areas of other femtocells 125 potentially sharing the same
PSC prior to the de-registration. Notably, timer-based
de-registration may be undesirable in certain configurations. For
example, after registration, a handover request may not be received
for a long time due to the UE 115 being idle or due to some other
circumstance. If the UE 115 were implicitly de-registered prior to
receiving the handover request, benefits of the registration may be
lost.
[0172] FIGS. 7-10 are discussed above primarily in context of
pre-registration (i.e., communicating the OOB proximity detection
for a UE 115 prior to receiving a handover request for the UE 115).
It may be appreciated that similar techniques may be used in cases
where the OOB proximity detection is communicated subsequent to
receiving a handover request implicating the UE 115. For example,
as described above, the femtocell gateway 540 may be unable to
determine the appropriate target femtocell 125 for hand-in based
only on the cell identifier provided in the handover request from
the SGSN 650, and may communicate a handover request to all
candidate target femtocells 125 (e.g., simultaneously).
[0173] FIG. 11 shows a flow diagram of a method 1100 for
implementing certain active hand-in functionality without
pre-registration (i.e., without having communicated the OOB
proximity detection for a UE 115 prior to receiving a handover
request for the UE 115) in accordance with various embodiments. The
method 1100 may, for example, be performed by the femtocell 125 of
FIG. 1, 2A, 2B, 5, 6A, or 6B. The method 1100 may begin at block
1105 by receiving a handover request at a femtocell 125 via its
in-band frequency module 230 from a femtocell gateway 540 for a
designated UE 115. The femtocell gateway 540 may send the handover
request to a set of candidate femtocells that share the same PSCs.
Note that the handover request may be sent to each femtocell with a
"dummy ID", instead of the target femtocell macro identifier. The
"dummy ID" may indicate to the femtocell 125 that the handover
request is for a PSC confusion scenario where multiple candidate
femtocells 125 have been identified, hence, an OOB capable
femtocell 125 may use an OOB detection of a designated UE 115 (a UE
with mapping between a UE macro identifier and OOB identifier
stored in the femtocell). Otherwise, the femtocell 125 may use
legacy techniques like blind support or no support to respond to
the handover request.
[0174] At block 1110, the femtocell 125 may confirm that the UE 115
has an entry in the UE mappings 219 between the UE macro identifier
and OOB identifier. For example, if the UE 115 is in the
femtocell's 125 UE mappings 219 (e.g., in the femtocell's 125
access control list), the femtocell 125 may be able to use the UE's
115 IMSI, etc. to determine the UE's 115 OOB identifier (e.g.,
BD_ADDR). Then the OOB frequency module 240 of the femtocell 125
may be used to detect the UE 115 over an OOB communications
channel. Note that if a mapping for the UE was not found in UE
mapping 219, the femtocell 125 may be unable to use OOB detection
and hence, send a handover response based on other techniques such
as blind support or no support as shown in block 1115.
[0175] Having used OOB communication to detect the UE 115 at block
1120, a determination is made at block 1125 as to whether the UE
115 is detected in proximity to the femtocell 125. If it is
determined at block 1125 that the UE 115 is not detected in
proximity to the femtocell 125, the femtocell 125 may communicate a
detection failure response to the femtocell gateway 540 at block
1130 through a handover response with a "reject" flag. If it is
determined at block 1125 that the UE 115 is detected in proximity
to the femtocell 125, femtocell 125 may communicate a detection
successful response to the femtocell gateway 540 at block 1135.
[0176] Having successfully detected the UE 115 in its proximity,
the femtocell 125 may handle the hand-in in various ways. According
to one technique, the femtocell 125 registers the UE 115 for
hand-in to the femtocell gateway 540 (e.g., by communicating the
cell identifier of the UE 115 from the femtocell 125 to the
femtocell gateway 540 in a registration message such as with block
715 of FIG. 7A) followed by a handover response with an "accept"
flag 1145. According to another technique, the femtocell 125
communicates successful proximity detection with a handover
response with an "accept" and "OOB indicator" flags 1140. The
reception of an OOB indicator in a handover response message at
block 1228 or a UE 115 registration preceding the handover response
with an "accept" flag at block 908, alerts the femtocell gateway
540 to the fact that the handover response is based on OOB
detection and the UE has been successfully detected. The femtocell
gateway may give precedence to such responses over handover
responses based on other techniques like blind hand-off or no
support since these techniques are less reliable. Having
communicated a successful detection to the femtocell gateway 540,
the UE's 115 communications may be handed over to the femtocell 125
in a reliable fashion.
[0177] FIGS. 7-11 focus primarily on handling of hand-in
functionality from the perspective of a femtocell 125. As described
above and as illustrated by the call flow diagram 900 of FIG. 9,
active hand-in functionality is further facilitated by actions of
the femtocell gateway 540. Techniques for handling of hand-in
functionality from the perspective of a femtocell gateway 540 are
described in FIGS. 12-14.
[0178] Turning to FIG. 12, a flow diagram is shown of a method 1200
for handling femtocell-assisted hand-in at a femtocell gateway in
accordance with various embodiments. The method 1200 may, for
example, be performed by the femtocell gateway 540 of FIG. 5, 6A,
or 6B. The method 1200 may begin at block 1205 a handover request
may be received, at a femtocell gateway 540 from a macro network
100. The handover request may be configured to direct a UE 115 to
hand off active communications with the macro network 100 from a
macrocell 105 to a designated femtocell 125 with a first femtocell
identifier.
[0179] At block 1210, it may be determined at the femtocell gateway
540 whether any of multiple femtocells 125 registered the UE 115
with the femtocell gateway 540 prior to receiving the handover
request. Block 1210 may include determining whether an OOB
proximity detection is received from any of the multiple femtocells
prior to receiving the handover request. The OOB proximity
detection may include a macro identifier of the UE 115, such as an
IMSI. The OOB proximity detection may include an OOB identifier of
the UE 115. In some cases, the femtocell gateway 540 may determine
whether the macro identifier of the UE 115 corresponds to the OOB
identifier of the UE 115. In some embodiments, the femtocell
gateway 540 may determine whether two or more femtocells of the
multiple femtocells are addessable by the femtocell gateway 540
according to the first femtocell identifier. The femtocell gateway
540 may then determine whether the designated femtocell is one of
the two or more femtocells addressable according to the first
femtocell identifier utilizing a second femtocell identifier.
[0180] At block 1215, the femtocell gateway 540 may communicate the
handover request to the designated femtocell 125. Some embodiments
of method 1200 may further include determining whether the
designated femtocell 125 is uniquely addressable by the femtocell
gateway 540 according to the first femtocell identifier.
Communicating the handover request from the femtocell gateway 540
to designated femtocell may utilize the first femtocell
identifier.
[0181] Turning to FIG. 13A, a flow diagram is shown of a method
1300-a for handling femtocell-assisted active hand-in at a
femtocell gateway in accordance with various embodiments. The
method 1300-a may, for example, be performed by the femtocell
gateway 540 of FIG. 5, 6A, or 6B. The method 1300-a may begin at
block 1205 by receiving a handover request at the femtocell gateway
540 from a macro network 100 (e.g., from the SGSN 650 over the core
network). The handover request may be configured to direct a UE 115
to hand off active macro communications from a current (source)
macrocell 105 to a designated femtocell 125. The designated
femtocell 125 may be one of a number of femtocells 125 in
communication with the femtocell gateway 540, and each femtocell
125 may be identifiable by a first femtocell identifier (e.g., a
PSC). Each femtocell 125 may also be identifiable by a second
femtocell identifier, which may be a femtocell gateway-oriented
identifier (e.g., an identifier used by the femtocell gateway 540
to uniquely address all the femtocells 125 in communication with
the femtocell gateway 540). Note that this femtocell gateway
identifier can be similar to the unique identifier broadcasted in
the system information of the femtocells 125. In addition, the
femtocell gateway 540 can send handover requests to the femtocells
125 with an identifier termed the "dummy ID" which indicates to the
femtocells 125 that the handover request is for a PSC confusion
scenario where multiple candidate femtocells 125 have been
identified, hence, an OOB capable femtocell 125 with an OOB
frequency module 240 may use the OOB detection for a designated UE
115. Otherwise, the femtocell 125 may use legacy techniques like
blind support or no support to respond to the handover request.
Note that the "dummy ID" may have a similar format as the femtocell
gateway oriented identifier but it has not been assigned to any
femtocell 125.
[0182] As described above, the first femtocell identifier may be
substantially non-unique. For example, a number of femtocells 125
in the same macro sector may share the same first femtocell
identifier (e.g., PSC). On the contrary, the second femtocell
identifier may be substantially or completely unique. For example,
the second femtocell identifier may be at least unique enough so as
to be used to reliably identify a particular femtocell 125 from the
perspective of the femtocell gateway 540. It may be assumed that
the designated femtocell 125 is identified in the handover request
by its first femtocell identifier. For example, the first femtocell
identifier may be how the femtocell 125 is identified by the UE 115
as part of its measurement report, which is then used to trigger
the handover request.
[0183] At block 1210, a determination may be made as to whether any
femtocells 125 registered the macro identifier of the UE 115 (e.g.,
the IMSI) with the femtocell gateway 540 prior to receiving the
handover request at the femtocell gateway 540. If it is determined
at block 1210 that a particular ("registering") femtocell 125
registered the macro identifier of the UE 115 with the femtocell
gateway 540 prior to receiving the handover request at the
femtocell gateway 540, the designated femtocell 125 may be
determined to be the "registering" femtocell 125 at block 1305
(i.e., the "registering" femtocell 125 may be determined to be the
target femtocell 125 for hand-in). Accordingly, at block 1215, the
handover request may be communicated from the femtocell gateway 540
to the designated femtocell 125 (i.e., the "registering" femtocell
125) according to its second femtocell identifier. For example, the
femtocell gateway 540 may maintain a mapping for all its connected
femtocells 125 between their respective first and second
identifiers. The femtocell gateway 540 may uniquely address the
handover request to the designated femtocell 125 by mapping the
received first femtocell identifier (which may be substantially
non-unique) to the maintained second femtocell identifier (which
may be substantially unique). After the handover request is sent to
the femtocell 125, at block 1310, an acknowledgement message (e.g.
handover request message with an "accept" may be received by the
femtocell gateway 540 from the designated femtocell 125.
[0184] If it is determined at block 1210 that no femtocells 125
registered the macro identifier of the UE 115 (using an OOB
proximity detection or UE registration message) with the femtocell
gateway 540 prior to receiving the handover request at the
femtocell gateway 540, the femtocell gateway 540 may use one or
more techniques to handle the hand-in without being able to exploit
pre-registration. For example, at block 1315, a set of candidate
target femtocells 125 may be determined from those femtocells 125
registered at the femtocell gateway 540. For example, the femtocell
gateway 540 may include in the set of candidates all femtocell 125
in the relevant macro sector associated with the received first
femtocell identifier. As described above, the femtocell gateway 540
may send handover request for the designated UE 115 to any or a set
of the femtocells 125 in the candidate list.
[0185] In some embodiments, the handover request sent to the
femtocells 125 of the candidate list are directed to detect the UE
115 at block 1320. In some cases, the handover request may include
a "dummy ID" so femtocells 125 with OOB frequency modules 240 may
be directed to detect the UE 115. For example, the femtocells 125
may engage in proximity detection according to techniques described
with reference to FIG. 11. It may be possible that none of the
candidate femtocells 125 will detect the UE 115 in its proximity,
or that multiple candidate femtocells 125 will detect the UE 115 in
their proximity. Various techniques may be used to abort the method
1300 where there is no successful detection, or to select a "best"
result when there are multiple successes. Notably, embodiments may
use only OOB detection. Use of the OOB detection may obviate the
possibility that multiple successes would occur. Accordingly, and
for the sake of clarity, it is assumed that one of the candidate
femtocells 125 is identifiable by the femtocell gateway 540 as
having successfully detected the UE 115 in its proximity.
[0186] At block 1325, an indication is received at the femtocell
gateway 540 from one of the candidate femtocells 125 that the UE
115 is in its proximity. The femtocell 125 that indicates that the
UE 115 is in its proximity may be referred to as a successful
femtocell. This may be a registration message accompanied by a
handover response with an "accept" flag or a handover response with
"accept" and "OOB indicator" flags, etc.
[0187] At block 1330, the femtocell gateway 540 may direct the
designated UE 115 to be handed over to the designated (registering)
femtocell 125 determined from blocks 1210, 1305, 1215, and/or 1310.
Otherwise, if there was no pre-registration for the designated UE
115 in 1210, the femtocell gateway 540 may direct the designated UE
125 to be handed over to the designated femtocell 125 determined
from blocks 1210, 1315, 1320, and/or 1325.
[0188] In some embodiments, the femtocell gateway 540 may monitor
an elapsed time subsequent to directing the set of candidate
femtocells 125 to detect whether UE 115 is in its proximity. The
femtocell gateway 540 may determine whether the indication from one
of the candidate femtocells 125 that the UE 115 is in its proximity
is received while the elapsed time is within a predefined time
limit. The femtocell gateway 540 may communicate the handover
request to the designated femtocell 125 when the indication from
the one of the candidate femtocells 125 that the UE 115 is in its
proximity is received within the predefined time limit.
[0189] Turning to FIG. 13B, a flow diagram is shown of a method
1300-b for handling femtocell-assisted active hand-in at a
femtocell gateway in accordance with various embodiments. The
method 1300-b may, for example, be performed by the femtocell
gateway 540 of FIG. 5, 6A, or 6B. Method 1300-b may utilize aspects
of method 1300-a of FIG. 13A, such as blocks 1205 that are not
shown in this diagram. For the sake of added clarity, reference
numerals from FIG. 13A may used with the addition of a lower-case
"a" to indicate a possible illustrative implementation or variation
of the corresponding block from FIG. 13A in the context of FIG.
13B.
[0190] Method 1300-b may include at block 1210-a determining that
none of the of multiple femtocells 125 registered the UE 115 prior
to receiving the handover request. At block 1315-a, a set of
candidate femtocells 125 from the multiple femtocells may be
determined. The set of candidate femtocells may be identified by at
least the first femtocell identifier in some embodiments. At block
1335, each of the candidate femtocells 125 may be directed with an
OOB hand-in cause value in the handover request to detect whether
the UE 115 is in its proximity. The OOB hand-in cause value may be
unrecognizable by some femtocells 125, while some femtocells 125
with OOB capabilities may recognize the OOB hand-in cause value. A
dummy identifier may also be transmitted in some cases. Block 1335
may be referred to as a "first tier" handover request.
[0191] At block 1340, it may be determined whether an OOB accept
message from one of the candidate femtocells 125 is received. The
OOB accept message may indicate that the one of the candidate
femtocells 125 detects the UE 115 in its proximity. If it is
determined that an OOB accept message has been received, the
candidate femtocell 125 associated with the OOB accept message may
identified as the designated femtocell 125.
[0192] If an OOB accept message is not received, it may be that
only OOB reject message(s) from one or more of the candidate
femtocells and/or error indication message(s) from one or more of
the candidate femtocells may be received at block 1350. A "second
tier" handover request may be made as a result. At block 1355, a
handover request with a normal cause value may be transmitting to
each of the set of candidate femtocells 125. The normal cause value
may be recognizable by the candidate femtocells 125 in general. A
dummy identifier may also be transmitted in some cases. The
femtocell cells 125 may respond using legacy techniques such as a
handover response with blind accept or blind reject flag. At block
1360, at least a blind accept or a blind reject from one or more of
the candidate femtocells 125 may be received. At block 1365, the
candidate femtocell 125 associated with the blind accept may be
identified as the designated femtocell.
[0193] At block 1330-a, the designated UE 115 may be directed to
hand in from its current connected macrocell 105 to the designated
femtocell 125.
[0194] Exemplary call flow diagrams 1400-a and 1400-b, illustrating
an active hand-in according to the methods 1100, 1200, and/or
1300-a of FIGS. 11, 12, and/or 13A, respectively, are shown in FIG.
14A and FIG. 14B. The call flow diagrams 1400 are similar to the
call flow diagram 900 of FIG. 9, and similar messaging is described
according to the same reference numbers as those used in FIG. 9. It
will be appreciated that the messaging, while similar, may not be
identical according to the circumstances of the different call
flows. In particular, FIG. 9 describes a pre-registration scenario,
while FIGS. 14A and 14B describe a post-registration scenario. In
FIG.14A, a post-registration scenario is illustrated where the OOB
proximity detection may be communicated from the femtocell 125 to
the femtocell gateway 540 by a combination of UE registration
message and a handover request with an "accept" flag. In FIG.14B, a
post-registration scenario is illustrated where the OOB proximity
detection may be communicated from the femtocell 125 to the
femtocell gateway 540 by a handover request with "accept" and OOB
indicator flags.
[0195] As in FIG. 9, the call flow diagrams 1400 show
communications between a UE 115, a currently connected (source)
macrocell 105 and/or RNC120, a source SGSN 650, a target femtocell
gateway 540, and two potential target femtocell 125-a and 125-b.
For the sake of avoiding excess detail, the source macrocell base
station may include a source macrocell 105 in communication with a
macro RNC 120, and signaling between those elements is not shown.
It is assumed for the sake of the call flow diagrams 1400 that the
potential target femtocells 125 have a common cell identifier
(e.g., they have the same PSC). As such, it may be necessary to
reliably determine the appropriate one of the potential target
femtocells 125 to ensure a successful active hand-in.
[0196] The call flow diagrams 1400 may begin at block 904 with the
UE 115 currently engaged in an active macro communications, like a
voice call or a data call, facilitated by the source SGSN 650 via
the source macrocell 105 and/or the RNC 120. At some time, the UE
115 may move into the femto coverage area of the femtocell 125,
detect the femtocell 125, and send a measurement report to the
source macrocell 105 and/or RNC 120 at block 916. The measurement
report may include the pilot strength of the femtocell 125 as
observed by the UE 115 and the PSC of the femtocell 125. The source
source macrocell 105 and/or RNC 120 may determine that a handover
is required according to the measurement report and communicates a
relocation required message to the source SGSN 650 at block 920. At
block 924, the relocation required message may be communicated
(e.g., as a relocation request message over the core network) from
the source SGSN 650 to the target femtocell gateway 540.
[0197] It is assumed in FIGS. 14A and 14B that, at the block when
the relocation request 924 is received by the femtocell gateway
540, the UE 115 has still not been registered by any femtocells 125
sharing the identifier, such that multiple femtocells 125 may be
candidate target femtocells 125 for the hand-in. In some cases, the
femtocell gateway 540 may send handover request with "dummy ID" to
the candidate femtocells 125 at block 1402. At block 1404, the OOB
frequency module 240 associated with a first of the potential
target femtocell 125-a (e.g., the OOB frequency module 240 and the
in-band frequency module may be integrated into the first potential
target femtocell 125-a) detects the UE 115 in its proximity.
[0198] In FIG. 14A, when the UE 115 is detected by the first of the
potential target femtocell 125-a, the femtocell 125-a may send an
OOB proximity detection to the target femtocell gateway 540 by
sending a registration message for the designated UE 115 at block
1408 and a handover response with an "accept" flag at block 932.
Having received the OOB proximity detection and the handover
request, the target femtocell gateway 540 can determine the
designated femtocell 125-a. . Note that the femtocell 125-b may
also receive the handover request at block 1402 and may reply back
to the target femtocell gateway 540 with a handover response based
on blind off at block 1410. As described above, the target
femtocell gateway 540 may distinguish the handover response based
on OOB detection from those based on the blind off, and hence can
determine the designated femtocell 125-a.
[0199] In FIG. 14B, after OOB detection at block 1404, the
femtocells 125 may send handover response messages at block 1410.
While multiple potential target femtocells 125 may send handover
response messages, only target femtocell 125-a (i.e., which
detected the UE 115 in its proximity) communicates an OOB proximity
detection to the femtocell gateway 540 along with its handover
response (e.g., by sending "accept" and OOB indicator flags at
block 1406).
[0200] Irrespective of whether the OOB proximity detection or
indicator in FIG. 14A or FIG. 14B is used, the handover may then
communicated to the UE 115 via the core network and the macro
network 100. Notably, while referred to generically herein in some
instances as "handover requests" for the sake of simplicity, each
related message may, in fact, be of a different form and/or
purpose. For example, as illustrated, a handover response may be
communicated from the target femtocell gateway 540 to the source
SGSN 650 as a relocation response message at block 936; a
relocation command may be communicated from the source SGSN 650 to
the source macrocell 105 and/or RNC 120 at block 940; and/or a
relocation command may be communicated from the source macrocell
105 and/or RNC to the UE 115 as a physical channel configuration
message at block 944.
[0201] At block 948, the UE 115 may communicate an acknowledgement
message, the physical channel reconfiguration message to the source
macrocell 105 and/or RNC 120. At block 952, the UE may attempt to
detect and synchronize with the first potential femtocell 125-a. At
block 956, the UE 115 may communicate a handover complete message
to the first potential target femtocell 125-a; and the first
potential target femtocell 125-a may communicate the handover
complete message to the target femtocell gateway 540 at block 960.
Although not shown in the figure, the Handover complete message may
be relayed to the source macrocell 105 and/or RNC 120 so that the
radio link set-up for the UE 115 can be deleted. Having completed
the hand-in, the UE's 115 active macro communications (e.g., the
voice call) continue at block 964 facilitated by the appropriately
identified target femtocell 125 (i.e., previously the first
potential target femtocell 125-a) instead of by the source
macrocell 105 and/or RNC 120.
[0202] Other embodiments for facilitating the active hand-in in a
post-registration scenario may include tiered approaches. With this
method, the femtocell gateway 540 may give priority to handover
responses from OOB-capable femtocells 125 (e.g., those having an
OOB frequency module 240 that uses the OOB link for detection),
over responses from femtocells 125 that are not OOB-capable. This
prioritization may be desirable because the responses based on OOB
detection may be more reliable than the default response
configurations in femtocells that typically involve a "blind"
accept or reject of the handover request.
[0203] In these embodiments, the femtocell gateway 540 may attempt
to first obtain handover responses based on OOB detection by
sending "first tier" handover request targeted towards OOB-capable
femtocells 125 only. If no handover response with an "accept" flag
is received by the femtocell gateway 540, the femtocell gateway 540
may send a "second tier" handover request message to all candidate
femtocells 125. The "tiered approach" can be implemented by
defining a new "cause value" field in the handover request, thereby
obtaining "OOB capability awareness" from the core network 130 of
FIG. 1 about the femtocells 125 supported by the femtocell gateway
540, etc. The "cause value" field may typically be used in handover
request in deployed networks to communicate to the femtocells 125
the reason for handover request.
[0204] In FIG. 15A and FIG. 15B, call flows for the embodiments in
which the "cause value" is used in the "tiered approach" for post
registration detection are discussed. FIG. 15A and/or FIG. 15B may
illustrate an active hand-in according to the method 1300-b of FIG.
13B. FIG. 15A and/or FIG. 15B show aspects that may be implemented
as aspects of method 1300-b of FIG. 13B. FIG. 15A illustrates a
scenario where OOB detection is successful, and FIG. 15B
illustrates a scenario where the OOB detection is unsuccessful. As
in FIGS. 9, 14A, and/or 14B, the call flow diagrams 1500-a and
1500-b show communications between a UE 115, a currently connected
(source) macrocell 105 and/or RNC 105/120, a source SGSN 650, a
target femtocell gateway 540, and two potential target femtocells
125. For the sake of avoiding excess detail, the source macrocell
base station may include the source macrocell 105 (which may be
source macro Node B) in communication with a macro RNC 120, and
signaling between those elements is not shown. It is assumed for
the sake of the call flow diagrams 1500 that the potential target
femtocells 125 have a common cell identifier (e.g., they have the
same PSC). As such, it may be necessary to reliably determine the
appropriate one of the potential target femtocells 125 to ensure a
successful active hand-in.
[0205] The call flow diagrams 1500 begin at block 904 with the UE
115 currently engaged in an active macro communications, like a
voice call or a data call, facilitated by the source SGSN 650 via
the source macrocell 105 and/or RNC 120. At some time, the UE 115
may move into the femto coverage area of a femtocell 125, detect
the femtocell 125, and send a measurement report to the source
macrocell 105 and/or RNC 120 at block 916. The measurement report
may include the pilot strength of the femtocell 125 as observed by
the UE 115 and the PSC of the femtocell 125. The source macrocell
105 and/or RNC 120 may determine that a handover is required
according to the measurement report and communicates a relocation
required message to the source SGSN 650 at block 920. At block 924,
the relocation required message is communicated (e.g., as a
relocation request message over the core network) from the source
SGSN 650 to the target femtocell gateway 540.
[0206] It is assumed in FIG. 15A that at the block when the
relocation request 924 may be received by the femtocell gateways
540, the UE 115 has still not been registered by any femtocells 125
sharing the identifier, such that multiple femtocells 125 are
candidate target femtocells 125 for the hand-in. As a result, the
femtocell gateway 540 may send the "first tier" handover request
with "dummy ID" and an unrecognized "cause value" 1502 (e.g. "OOB
hand-in") to the candidate femtocells 125. At block 1504,
femtocells 125 without the OOB capability (e.g., illustrated as
femtocell 125-b) respond back with an "error indication" in the
handover response. At block 1505, an OOB-capable femtocell 125
(e.g., illustrated as the first potential target femtocell. 125-a,
which is assumed to be integrated with an OOB frequency module 240)
may detect the UE 115 in its proximity and send a handover response
with an "accept" flag to the femtocell gateway 540 at block
1506.
[0207] The handover may then be communicated to the UE 115 via the
core network and the macro network 100. Notably, while referred to
generically herein in some instances as "handover requests" for the
sake of simplicity, each related message may, in fact, be of a
different form and/or purpose. For example, as illustrated, a
handover response may be communicated from the target femtocell
gateway 540 to the source SGSN 650 as a relocation response message
at block 936; a relocation command may be communicated from the
source SGSN 650 to the source macrocell 105 and/or RNC 120 at block
940; and a relocation command may be communicated from the source
macrocell 105 and/or RNC 120 to the UE 115 as a physical channel
configuration message at block 944.
[0208] At block 948, the UE 115 may communicate an acknowledgement
message, the physical channel reconfiguration message to the source
macrocell 105 and/or RNC 120. At block 952, the UE 115 may attempt
to detect and synchronize with the first potential femtocell 125-a;
at block 956, the UE 115 may communicate a handover complete
message to the first potential target femtocell 125-a; and the
first potential target femtocell 125-a may communicate the handover
complete message to the target femtocell gateway 540 at block 960.
Although not shown in the figure, the Handover complete message may
be relayed to the source macrocell 105 and/or RNC 120 so that the
radio link set-up for the UE 115 can be deleted. Having completed
the hand-in, the UE's 115 active macro communications (e.g., the
voice call) may continue at block 964 facilitated by the
appropriately identified target femtocell 125 (i.e., previously the
first potential target femtocell 125-a) instead of by the source
macrocell 105 and/or RNC 120.
[0209] It is assumed in FIG. 15B that, at the block when the
relocation request 924 is received by the femtocell gateway 540,
the UE 115 may still not been registered by any femtocell 125
sharing the identifier, such that multiple femtocells 125 may be
candidate femtocells 125 for the hand-in. As a result, the
femtocell gateway 540 may send the "first tier" handover request
with "dummy ID" and an unrecognized "cause value" 1502 (e.g. "OOB
hand-in") to the candidate femtocells 125-b without the OOB
capability. At block 1504, femtocells 125 without the OOB
capability (e.g., femtocells 125-b) may respond back to the
femtocell gateway 540 with an "error indication" in the handover
response. At block 1508, OOB-capable potential target femtocells
125 (e.g., femtocells 125-a) may recognize the "cause value" and
attempt to detect the UE 115 but the detection was unsuccessful.
Therefore, all such femtocells 125-a may send handover responses
with a "reject" flag 1510 to the femtocell gateway 540.
[0210] After the femtocell gateway 540 collects all the responses
and no handover response with an "accept" flag is received, the
femtocell gateway 540 may then sends the "second tier" handover
requests 1512 with a "dummy ID" and a "cause value" that can be
recognized by all candidate femtocells 125. The femtocells 125-a
with OOB capability may not use the OOB detection, but instead all
femtocells 125 respond to the handover requests 1512 using legacy
techniques such as handover response with blind "accept" or
"reject" flags. After the femtocell gateway 540 receives the
handover responses 1514, it may uses legacy active hand-in support
(which are typically less reliable than using the OOB detection) in
implementing hand-in. This legacy support might require that the
femtocell gateway 540 to blindly select one femtocell 125 as the
designated femtocell 125 or use other criterion (e.g. signal
strength) to select the best "femtocell" 125 if such information is
available at the femtocell gateway 540.
[0211] If the femtocell gateway 540 had prior knowledge of which
femtocells 125 are OOB capable (OOB capability awareness), the
"first tier" handover request 1502 in FIGS. 15A and 15B can be sent
only to femtocells 125-a and not to all candidate femtocells 125.
This may reduce the signaling involved in the active hand-in
process.
[0212] Techniques described herein may be used for various wireless
communication systems such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and
other systems. The terms "system" and "network" are often used
interchangeably. A CDMA system may implement a radio technology
such as CDMA2000, Universal Terrestrial Radio Access (UTRA), etc.
CDMA2000 covers IS-2000, IS-95, and IS-856 standards. IS-2000
Releases 0 and A are commonly referred to as CDMA2000 1X, 1X, etc.
IS-856 (TIA-856) is commonly referred to as CDMA2000 1xEV-DO, High
Rate Packet Data (HRPD), etc. UTRA includes Wideband CDMA (WCDMA)
and other variants of CDMA. A TDMA system may implement a radio
technology such as Global System for Mobile Communications (GSM).
An OFDMA system may implement a radio technology such as Ultra
Mobile Broadband (UMB), Evolved UTRA (E-UTRA), IEEE 802.11 (Wi-Fi),
IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, etc. UTRA and E-UTRA
are part of Universal Mobile Telecommunication System (UMTS). 3GPP
Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are new releases
of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM
are described in documents from an organization named "3rd
Generation Partnership Project" (3GPP). CDMA2000 and UMB are
described in documents from an organization named "3rd Generation
Partnership Project 2" (3GPP2). The techniques described herein may
be used for the systems and radio technologies mentioned above, as
well as for other systems and radio technologies.
[0213] The various operations of methods described above may be
performed by any suitable means capable of performing the
corresponding functions. The means may include various hardware
and/or software component(s) and/or module(s), including, but not
limited to a circuit, an application specific integrate circuit
(ASIC), or processor.
[0214] The various illustrative logical blocks, modules, and
circuits described may be implemented or performed with a general
purpose processor, a digital signal processor (DSP), an ASIC, a
field programmable gate array signal (FPGA), or other programmable
logic device (PLD), discrete gate, or transistor logic, discrete
hardware components, or any combination thereof designed to perform
the functions described herein. A general purpose processor may be
a microprocessor, but in the alternative, the processor may be any
commercially available processor, controller, microcontroller, or
state machine. A processor may also be implemented as a combination
of computing devices, e.g., a combination of a DSP and a
microprocessor, a plurality of microprocessors, one or more
microprocessors in conjunction with a DSP core, or any other such
configuration.
[0215] The steps of a method or algorithm described in connection
with the present disclosure, may be embodied directly in hardware,
in a software module executed by a processor, or in a combination
of the two. A software module may reside in any form of tangible
storage medium. Some examples of storage media that may be used
include random access memory (RAM), read only memory (ROM), flash
memory, EPROM memory, EEPROM memory, registers, a hard disk, a
removable disk, a CD-ROM and so forth. A storage medium may be
coupled to a processor such that the processor can read information
from, and write information to, the storage medium. In the
alternative, the storage medium may be integral to the processor. A
software module may be a single instruction, or many instructions,
and may be distributed over several different code segments, among
different programs, and across multiple storage media.
[0216] The methods disclosed herein comprise one or more actions
for achieving the described method. The method and/or actions may
be interchanged with one another without departing from the scope
of the claims. In other words, unless a specific order of actions
is specified, the order and/or use of specific actions may be
modified without departing from the scope of the claims.
[0217] The functions described may be implemented in hardware,
software, firmware, or any combination thereof If implemented in
software, the functions may be stored as one or more instructions
on a tangible computer-readable medium. A storage medium may be any
available tangible medium that can be accessed by a computer. By
way of example, and not limitation, such computer-readable media
can comprise RAM, ROM, EEPROM, CD-ROM, or other optical disk
storage, magnetic disk storage, or other magnetic storage devices,
or any other tangible medium that can be used to carry or store
desired program code in the form of instructions or data structures
and that can be accessed by a computer. Disk and disc, as used
herein, include compact disc (CD), laser disc, optical disc,
digital versatile disc (DVD), floppy disk, and Blu-ray.RTM. disc
where disks usually reproduce data magnetically, while discs
reproduce data optically with lasers.
[0218] Thus, a computer program product may perform operations
presented herein. For example, such a computer program product may
be a computer readable tangible medium having instructions tangibly
stored (and/or encoded) thereon, the instructions being executable
by one or more processors to perform the operations described
herein. The computer program product may include packaging
material.
[0219] Software or instructions may also be transmitted over a
transmission medium. For example, software may be transmitted from
a website, server, or other remote source using a transmission
medium such as a coaxial cable, fiber optic cable, twisted pair,
digital subscriber line (DSL), or wireless technology such as
infrared, radio, or microwave.
[0220] Further, modules and/or other appropriate means for
performing the methods and techniques described herein can be
downloaded and/or otherwise obtained by a user terminal and/or base
station as applicable. For example, such a device can be coupled to
a server to facilitate the transfer of means for performing the
methods described herein. Alternatively, various methods described
herein can be provided via storage means (e.g., RAM, ROM, a
physical storage medium such as a CD or floppy disk, etc.), such
that a user terminal and/or base station can obtain the various
methods upon coupling or providing the storage means to the device.
Moreover, any other suitable technique for providing the methods
and techniques described herein to a device can be utilized.
[0221] Other examples and implementations are within the scope and
spirit of the disclosure and appended claims. For example, due to
the nature of software, functions described above can be
implemented using software executed by a processor, hardware,
firmware, hardwiring, or combinations of any of these. Features
implementing functions may also be physically located at various
positions, including being distributed such that portions of
functions are implemented at different physical locations. Also, as
used herein, including in the claims, "or" as used in a list of
items prefaced by "at least one of indicates a disjunctive list
such that, for example, a list of "at least one of A, B, or C"
means A or B or C or AB or AC or BC or ABC (i.e., A and B and C).
Further, the term "exemplary" does not mean that the described
example is preferred or better than other examples.
[0222] Various changes, substitutions, and alterations to the
techniques described herein can be made without departing from the
technology of the teachings as defined by the appended claims.
Moreover, the scope of the disclosure and claims is not limited to
the particular aspects of the process, machine, manufacture,
composition of matter, means, methods, and actions described above.
Processes, machines, manufacture, compositions of matter, means,
methods, or actions, presently existing or later to be developed,
that perform substantially the same function or achieve
substantially the same result as the corresponding aspects
described herein may be utilized. Accordingly, the appended claims
include within their scope such processes, machines, manufacture,
compositions of matter, means, methods, or actions.
* * * * *