U.S. patent application number 12/943612 was filed with the patent office on 2011-06-23 for keeping packet switched session in lte while circuit switched registered in wcdma.
This patent application is currently assigned to TELEFONAKTIEBOLAGET LM ERICSSON (PUBL). Invention is credited to Magnus OLSSON, Goran RUNE, Per SYNNERGREN, Erik WESTERBERG.
Application Number | 20110149852 12/943612 |
Document ID | / |
Family ID | 44150942 |
Filed Date | 2011-06-23 |
United States Patent
Application |
20110149852 |
Kind Code |
A1 |
OLSSON; Magnus ; et
al. |
June 23, 2011 |
KEEPING PACKET SWITCHED SESSION IN LTE WHILE CIRCUIT SWITCHED
REGISTERED IN WCDMA
Abstract
A wireless terminal, when already having a registration and/or
session for a packet switched (PS) service with a Long Term
Evolution (LTE) core network, makes a registration for a circuit
switched (CS) service over a Wide Band Code Division Multiplexing
(WCDMA) air interface with a circuit switched (CS) core network,
but in conjunction with the registration for the circuit switched
(CS) service maintains the registration and/or session for a packet
switched (PS) service with the Long Term Evolution (LTE) core
network.
Inventors: |
OLSSON; Magnus; (Stockholm,
SE) ; RUNE; Goran; (Linkoping, SE) ;
SYNNERGREN; Per; (LULEA, SE) ; WESTERBERG; Erik;
(ENSKEDE, SE) |
Assignee: |
TELEFONAKTIEBOLAGET LM ERICSSON
(PUBL)
Stockholm
SE
|
Family ID: |
44150942 |
Appl. No.: |
12/943612 |
Filed: |
November 10, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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61287575 |
Dec 17, 2009 |
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61287623 |
Dec 17, 2009 |
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61287438 |
Dec 17, 2009 |
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61287627 |
Dec 17, 2009 |
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61287630 |
Dec 17, 2009 |
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61287954 |
Dec 18, 2009 |
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Current U.S.
Class: |
370/328 |
Current CPC
Class: |
H04W 72/1215 20130101;
H04W 88/08 20130101; H04W 60/005 20130101; H04W 76/25 20180201;
H04L 5/0055 20130101; H04W 72/0446 20130101; H04W 88/02 20130101;
H04W 88/06 20130101; H04W 72/02 20130101; H04W 36/0022
20130101 |
Class at
Publication: |
370/328 |
International
Class: |
H04W 60/00 20090101
H04W060/00 |
Claims
1. A wireless terminal configured, when already having a
registration and/or session for a packet switched (PS) service with
a Long Term Evolution (LTE) core network, to make a registration
for a circuit switched (CS) service over a Wide Band Code Division
Multiplexing (WCDMA) air interface with a circuit switched (CS)
core network and, in conjunction with the registration for the
circuit switched (CS) service, maintaining the registration and/or
session for a packet switched (PS) service with the Long Term
Evolution (LTE) core network.
2. The wireless terminal of claim 1, wherein the wireless terminal
is configured to refrain from making a registration for a packet
switched (PS) service over the Wide Band Code Division Multiplexing
(WCDMA) air interface with a packet switched (PS) core network in
conjunction with making the registration for the circuit switched
(CS) service over the Wide Band Code Division Multiplexing (WCDMA)
air interface with the circuit switched (CS) core network.
3. The wireless terminal of claim 1, wherein the wireless terminal
is configured, in conjunction with the registration for the circuit
switched (CS) service, to refrain from performing a routing area
update towards a Wide Band Code Division Multiplexing (WCDMA)
packet switched (PS) core network.
4. The wireless terminal of claim 1, wherein the wireless terminal
is configured to maintain the registration and/or session for a
packet switched (PS) service with the Long Term Evolution (LTE)
core network until such time as a circuit switched (CS) is
established.
5. The wireless terminal of claim 1, wherein the wireless terminal
is configured to perform a routing area update towards a Wide Band
Code Division Multiplexing (WCDMA) packet switched (PS) core
network when a circuit switched (CS) is established.
6. The wireless terminal of claim 1, wherein the wireless terminal
comprises: a communication interface arranged to communicate over
the air interface a message configured to make the registration for
the circuit switched (CS) service; a mobility management unit
configured to make the registration for the circuit switched (CS)
service over the Wide Band Code Division Multiplexing (WCDMA) air
interface with the circuit switched (CS) core network while
maintaining the registration and/or session for a packet switched
(PS) service with the Long Term Evolution (LTE) core network.
7. A method of operating a wireless terminal comprising: when
already having a registration and/or session for a packet switched
(PS) service with a Long Term Evolution (LTE) core network, making
a registration for a circuit switched (CS) service over a Wide Band
Code Division Multiplexing (WCDMA) air interface with a circuit
switched (CS) core network; and maintaining the registration and/or
session for a packet switched (PS) service with the Long Term
Evolution (LTE) core network in conjunction with the registration
for the circuit switched (CS) service.
8. The method of claim 7, further comprising the wireless terminal
refraining from making a registration for a packet switched (PS)
service over the Wide Band Code Division Multiplexing (WCDMA) air
interface with a packet switched (PS) core network in conjunction
with making the registration for the circuit switched (CS) service
over the Wide Band Code Division Multiplexing (WCDMA) air interface
with the circuit switched (CS) core network.
9. The method of claim 7, further comprising the wireless terminal
refraining from performing a routing area update towards a Wide
Band Code Division Multiplexing (WCDMA) packet switched (PS) core
network in conjunction with the registration for the circuit
switched (CS) service.
10. The method of claim 7, further comprising the wireless terminal
refraining from performing a combined Location Area (LA)/routing
area (RA) update towards a Wide Band Code Division Multiplexing
(WCDMA) packet switched (PS) core network in conjunction with the
registration for the circuit switched (CS) service, and instead
performing a Location Area (LA) update toward the Wide Band Code
Division Multiplexing (WCDMA) packet switched (PS) core
network.
11. The method of claim 7, further comprising the wireless terminal
maintaining the registration and/or session for a packet switched
(PS) service with the Long Term Evolution (LTE) core network until
such time as a circuit switched (CS) is established.
12. The method of claim 7, further comprising the wireless terminal
performing a routing area update a Wide Band Code Division
Multiplexing (WCDMA) packet switched (PS) core network when a
circuit switched (CS) is established.
13. A communications network comprising: a Long Term Evolution
(LTE) core network; a circuit switched (CS) core network; a
wireless terminal configured, when already having a registration
and/or session for a packet switched (PS) service with the Long
Term Evolution (LTE) core network, to make a registration for a
circuit switched (CS) service over a Wide Band Code Division
Multiplexing (WCDMA) air interface with the circuit switched (CS)
core network and, in conjunction with the registration for the
circuit switched (CS) service, maintaining the registration and/or
session for a packet switched (PS) service with the Long Term
Evolution (LTE) core network.
14. The network of claim 13, wherein the wireless terminal is
configured to refrain from making a registration for a packet
switched (PS) service over the Wide Band Code Division Multiplexing
(WCDMA) air interface with a packet switched (PS) core network in
conjunction with making the registration for the circuit switched
(CS) service over the Wide Band Code Division Multiplexing (WCDMA)
air interface with the circuit switched (CS) core network.
15. The network of claim 13, wherein the wireless terminal is
configured, in conjunction with the registration for the circuit
switched (CS) service, to refrain from performing a routing area
update towards a Wide Band Code Division Multiplexing (WCDMA)
packet switched (PS) core network.
16. The network of claim 13, wherein the wireless terminal is
configured, in conjunction with the registration for the circuit
switched (CS) service, to refrain from performing a combined
Location Area (LA)/routing area (RA) update towards a Wide Band
Code Division Multiplexing (WCDMA) packet switched (PS) core
network and instead performing a Location Area (LA) update toward
the Wide Band Code Division Multiplexing (WCDMA) packet switched
(PS) core network.
17. The network of claim 13, wherein the wireless terminal is
configured to maintain the registration and/or session for a packet
switched (PS) service with the Long Term Evolution (LTE) core
network until such time as a circuit switched (CS) is
established.
18. The network of claim 13, wherein the wireless terminal is
configured to perform a routing area update a Wide Band Code
Division Multiplexing (WCDMA) packet switched (PS) core network
when a circuit switched (CS) is established.
19. The network of claim 13, wherein the wireless terminal
comprises: a communication interface arranged to communicate over
the air interface a message configured to make the registration for
the circuit switched (CS) service; a mobility management unit
configured to make the registration for the circuit switched (CS)
service over the Wide Band Code Division Multiplexing (WCDMA) air
interface with the circuit switched (CS) core network while
maintaining the registration and/or session for a packet switched
(PS) service with the Long Term Evolution (LTE) core network.
20. A method of operating a communications network comprising a
Long Term Evolution (LTE) core network; a circuit switched (CS)
core network; and a wireless terminal; the method comprising: when
already having a registration and/or session for a packet switched
(PS) service with a Long Term Evolution (LTE) core network, making
a registration for a circuit switched (CS) service over a Wide Band
Code Division Multiplexing (WCDMA) air interface with a circuit
switched (CS) core network; and maintaining the registration and/or
session for a packet switched (PS) service with the Long Term
Evolution (LTE) core network in conjunction with the registration
for the circuit switched (CS) service.
21. The method of claim 20, further comprising the wireless
terminal refraining from making a registration for a packet
switched (PS) service over the Wide Band Code Division Multiplexing
(WCDMA) air interface with a packet switched (PS) core network in
conjunction with making the registration for the circuit switched
(CS) service over the Wide Band Code Division Multiplexing (WCDMA)
air interface with the circuit switched (CS) core network.
22. The method of claim 20, further comprising the wireless
terminal refraining from performing a routing area update towards a
Wide Band Code Division Multiplexing (WCDMA) packet switched (PS)
core network in conjunction with the registration for the circuit
switched (CS) service.
23. The method of claim 20, further comprising the wireless
terminal maintaining the registration and/or session for a packet
switched (PS) service with the Long Term Evolution (LTE) core
network until such time as a circuit switched (CS) is
established.
24. The method of claim 20, further comprising the wireless
terminal performing a routing area update towards a Wide Band Code
Division Multiplexing (WCDMA) packet switched (PS) core network
when a circuit switched (CS) is established.
Description
RELATED APPLICATIONS
[0001] This application claims the priority of and is related to
the following United States Provisional patent applications, all of
which are incorporated herein by reference in their entireties:
[0002] U.S. Provisional Patent Application 61/287,575 (attorney
docket: 2380-1425) to Magnus Olsson et al., entitled "GSM and LTE
Multiplexing Systems", filed on Dec. 17, 2009.
[0003] U.S. Provisional Patent Application 61/287,623 (attorney
docket: 2380-1426) to Magnus Olsson et al., entitled "Measurement
Report Relay in Access Division Multiplexing Systems", filed on
Dec. 17, 2009.
[0004] U.S. Provisional Patent Application 61/287,438 (attorney
docket: 2380-1427) to Magnus Olsson et al., entitled "WCDMA and LTE
Multiplexing", filed on Dec. 17, 2009.
[0005] U.S. Provisional Patent Application 61/287,627 (attorney
docket: 2380-1428) to Magnus Olsson et al., entitled
"Telecommunications Multiplexing", filed on Dec. 17, 2009.
[0006] U.S. Provisional Patent Application 61/287,630 (attorney
docket: 2380-1429) to Magnus Olsson et al., entitled "Access
Division Multiplexing--Call Setup Performance Improvement", filed
on Dec. 17, 2009.
[0007] U.S. Provisional Patent Application 61/287,954 (attorney
docket: 2380-1433) to Magnus Olsson et al., entitled "Scheduled
Optimized for GSM and LTD Multiplexing", filed on Dec. 17,
2009.
[0008] This application is related to the following United States
patent applications, all of which are filed on same date herewith
and incorporated herein by reference in their entireties:
[0009] U.S. patent application Ser. No. ______ (attorney docket:
2380-1437) to Magnus Olsson et al., entitled "GSM and LTE
Multiplexing".
[0010] U.S. patent application Ser. No. ______ (attorney docket:
2380-1462) to Magnus Olsson et al., entitled "Link Report Relay in
Access Division Multiplexing Systems".
[0011] U.S. patent application Ser. No. ______ (attorney docket:
2380-1457) to Magnus Olsson et al., entitled "Maintaining Packet
Switched Session in LTE When Establishing GSM Circuit Switched
Call".
[0012] U.S. patent application Ser. No. ______ (attorney docket:
2380-1461) to Magnus Olsson et al., entitled "Call Setup For Access
Division Multiplexing".
[0013] U.S. patent application Ser. No. ______ (attorney docket:
2380-1460) to Magnus Olsson et al., entitled "Scheduling For Access
Division Multiplexing".
TECHNICAL FIELD
[0014] This technology pertains to wireless communications
networks, and particularly to access division multiplexing
(ADM).
BACKGROUND
[0015] In a typical cellular radio system, wireless terminals (also
known as mobile stations and/or user equipment units (UEs))
communicate via a radio access network (RAN) to one or more core
networks. The radio access network (RAN) covers a geographical area
which is divided into cell areas, with each cell area being served
by a base station, e.g., a radio base station (RBS), which in some
networks may also be called, for example, a "NodeB" (UMTS) or
"eNodeB" (LTE). A cell is a geographical area where radio coverage
is provided by the radio base station equipment at a base station
site. Each cell is identified by an identity within the local radio
area, which is broadcast in the cell. The base stations communicate
over the air interface operating on radio frequencies with the user
equipment units (UE) within range of the base stations.
[0016] In some versions of the radio access network, several base
stations are typically connected (e.g., by landlines or microwave)
to a controller node (such as a radio network controller (RNC) or a
base station controller (BSC)) which supervises and coordinates
various activities of the plural base stations connected thereto.
The radio network controllers are typically connected to one or
more core networks.
[0017] The Universal Mobile Telecommunications System (UMTS) is a
third generation mobile communication system, which evolved from
the second generation (2G) Global System for Mobile Communications
(GSM). UTRAN is essentially a radio access network using wideband
code division multiple access for user equipment units (UEs). In a
forum known as the Third Generation Partnership Project (3GPP),
telecommunications suppliers propose and agree upon standards for
third generation networks and UTRAN specifically, and investigate
enhanced data rate and radio capacity. Specifications for the
Evolved Universal Terrestrial Radio Access Network (E-UTRAN) are
ongoing within the 3.sup.rd Generation Partnership Project (3GPP).
The Evolved Universal Terrestrial Radio Access Network (E-UTRAN)
comprises the Long Term Evolution (LTE) and System Architecture
Evolution (SAE). Long Term Evolution (LTE) is a variant of a 3GPP
radio access technology wherein the radio base station nodes are
connected to a core network (via Serving Gateways, or SGWs) rather
than to radio network controller (RNC) nodes. In general, in LTE
the functions of a radio network controller (RNC) node are
distributed between the radio base stations nodes (eNodeB's in LTE)
and SGWs. As such, the radio access network (RAN) of an LTE system
has an essentially "flat" architecture comprising radio base
station nodes without reporting to radio network controller (RNC)
nodes.
[0018] Cellular Circuit-Switched (CS) telephony was introduced in
the first generation of mobile networks. Since then CS telephony
has become the largest service in the world with approximately 4
billion subscriptions sold. Even today, the main part of the mobile
operator's revenue comes from the CS telephony service (including
Short Message Services (SMS)), and the 2G GSM networks still
dominate the world in terms of subscriptions. 3G subscriptions are
increasing in volume, but that increase is less in part because of
users with handheld mobile terminals migrating from 2G to 3G and
more as a result of mobile broadband implemented via dongles or
embedded chipsets in laptops.
[0019] The long-term evolution (LTE) project within 3GPP aims to
further improve the 3G standard to, among other things, provide
even better mobile broadband to the end-users (higher throughput,
lower round-trip-times, etc.).
[0020] A common view in the telecommunication industry is that the
future networks will be all-IP networks. Based on this assumption,
the CS domain in was removed in the LTE work. As a result, the
telephony service cannot be used by a 3GPP Release 8 compliant LTE
terminal, unless one of the following four things is done:
(1) Implement circuit switched (CS) fallback (CSFB), so that an LTE
terminal falls back to 2G GSM when telephony service is used. (2)
Implement 3GPP IP Multimedia Subsystem (IMS)/Multimedia Telephony
(MMTel), which is a simulated CS telephony service provided over IP
and IMS that inter-works with the Public Switched Telephone Network
(PSTN)/Public Land Mobile Network (PLMN). (3) Implement a tunneling
solution with Unlicensed Mobile Access (UMA)/Generic Access Network
(GAN) over LTE where the CS service is encapsulated into an IP
tunnel. (4) Implement a proprietary Voice over IP (VoIP) solution
with PSTN/PLMN interworking.
[0021] All of these four possibilities have drawbacks. In deployed
GSM networks that do not have Dual Transfer Mode (DTM)
capabilities; CS and Packet Switched (PS) services cannot be used
in parallel. Hence, all PS services running prior to a call to or
from a terminal using Circuit Switched Fallback (CSFB) are put on
hold or are terminated. If the GSM network has DTM, the PS
performance will be greatly reduced (from 10's of Mbps to 10's to
100's of kbps). One drawback with the CS fallback approach is that
when calling or being called and the terminal is falling back to
GSM and the CS service from LTE. Circuit Switched Fallback (CSFB)
also prolongs call set-up time.
[0022] The IMS/MMTel approach uses a completely new core/service
layer that is IMS based. This provides new possibilities to enhance
the service but also comes with the drawback of a financial hurdle
for the operator to overcome. A new core network drives capital
expenditures (CAPEX), and integration of that core network drives
an initial operating expenditures (OPEX) increase. Further, the
IMS/MMTel approach needs features implemented in the terminals and
the legacy CS network in order to handle voice handover to/from the
2G/3G CS telephony service.
[0023] Using UMA/GAN over LTE is not a standardized solution so a
drawback is that it is a proprietary solution which may make
terminal availability a problem. It also adds additional functions
to the core/service layer in both the network and terminal, e.g., a
GAN controller in the network and GAN protocols in the UE
terminal.
[0024] The proprietary VoIP approach, if operator controlled, comes
with the same drawbacks as for the IMS/MMTel (new core/service
layer) approach along with the difficulties associated with it
being proprietary and handover to 2G/3G CS may not be
supported.
[0025] There is yet a further solution for using a legacy CS
telephony service with a wireless terminal such as a 3GPP release
8-compliant LTE terminal. In that further solution, also known as a
type of Access Division Multiplexing (ADM), transmissions of GSM CS
voice are interleaved in between LTE transmissions. See, e.g.,
PCT/SE2007/000358, which is incorporated herein by reference. In
one example implementation of such an ADM solution a wireless
terminal simultaneously communicates with two TDMA-based radio
systems, e.g., the wireless terminal can maintain communications
paths to both systems by means of alternating in time its
communication between the two systems. The toggling between the two
systems is on a time scale small enough to effectively yield a
simultaneous communication between the two systems.
[0026] The ADM solution attempts to achieve a good PS connection in
parallel with the telephony service when in LTE coverage but still
reusing the legacy CS core and deployed GSM network for the
telephony service to reduce costs but still maintain good coverage
for the telephony service.
[0027] The ADM solution may be implemented in several ways. A first
example implementation, illustrated in FIG. 1A, is a fully UE
centric solution where no coordination is needed between the GSM CS
core and a LTE PS core. A second example implementation,
illustrated by FIG. 1B, is a network assisted solution which can
either be based on circuit switched fallback (CSFB), or a solution
that only reuses paging over LTE.
[0028] From a radio perspective, the ADM solution can be realized
in any of three different ways: As a first example radio realized
embodiment illustrated in FIG. 2A, the LTE transmissions could be
multiplexed with the GSM transmissions on a GSM TDMA frame level.
In FIG. 2A, frames for GSM transmissions and frames of LTE
transmissions have different darkness shading. This first example
solution requires that the GSM circuit switched (CS) telephony
service only use the half rate codec. When GSM is running at half
rate, then every second GSM TDMA frame is not used by the user.
[0029] As a second example radio-realized embodiment illustrated in
FIG. 2B, the LTE transmissions could be multiplexed with the GSM
transmissions on GSM burst level. GSM transmits speech using
bursts, each with a duration of 0.577 ms. In speech operation,
after having sent one burst, the Rx/Tx part sleeps for 7*0.577 ms
until it wakes up again and do a new Rx/Tx process. In this second
example this time gap could be used for LTE transmissions.
[0030] As a third example radio-realized embodiment illustrated in
FIG. 2C, any of above can be used for transmission but by using
dual receiver for simultaneous reception of GSM and LTE in the
downlink for simplified operation.
[0031] The architecture and principles of the circuit switched
fallback (CSFB) are defined in, e.g., 3GPP TS 23.272, Circuit
Switched Fallback in Evolved Packet System, Stage 2 (Release 8),
which is abbreviated herein as "23.272" and which is incorporated
herein by reference in its entirety.
[0032] Long Term Evolution (LTE) access typically provides improved
packet switched (PS) session performance as compared to WCDMA and
GSM/GPRS. However, LTE is mainly available to PS-only devices, as
shown in FIG. 3 in which the dashed line represents the user plane
of the PS session.
[0033] The ADM solution such as that of PCT/SE2007/000358 targets,
e.g., co-existence between Long Term Evolution (LTE) and Global
System for Mobile communication (GSM). FIG. 4 shows what would
occur if a circuit switched (CS) voice-centric device could
register for CS services in GSM while keeping the PS session in
LTE. In FIG. 4 the dashed line represents the user plane of the PS
session and the solid line represents the CS registration (control
plane).
[0034] However, in the case of co-existence with WCDMA, the ADM
approach such as that of PCT/SE2007/000358 assumes that CS voice
centric devices need to camp on WCDMA as shown in FIG. 5. In FIG. 5
the dashed line represents the user plane of the PS session and the
green solid line represents the CS registration (control plane).
This means that CS voice centric devices cannot benefit from the
improved performance of the LTE access. (Typically, LTE provides
increased bandwidth and reduced latency (round-trip delay)).
[0035] Moving to WCDMA includes additional steps as shown in FIG. 6
and FIG. 7. In FIG. 6 (Cell Re-selection to WCDMA where combined
LA/RA Update is not used) the combined Location Area/Registration
Area (LA/RA) Update is not used; in FIG. 7 (Cell Re-selection to
WCDMA where combined LA/RA Update is used) the combined LA/RA
Update is used.
SUMMARY
[0036] In one of its aspects the technology disclosed herein
concerns a wireless terminal configured, when already having a
registration and/or session for a packet switched (PS) service with
a Long Term Evolution (LTE) core network, to make a registration
for a circuit switched (CS) service over a Wide Band Code Division
Multiplexing (WCDMA) air interface with a circuit switched (CS)
core network. The wireless terminal is configured, in conjunction
with the registration for the circuit switched (CS) service, to
maintain the registration and/or session for a packet switched (PS)
service with the Long Term Evolution (LTE) core network. In an
example embodiment, the wireless terminal is configured to refrain
from making a registration for a packet switched (PS) service over
the Wide Band Code Division Multiplexing (WCDMA) air interface with
a packet switched (PS) core network in conjunction with making the
registration for the circuit switched (CS) service over the Wide
Band Code Division Multiplexing (WCDMA) air interface with the
circuit switched (CS) core network. For example, in an example
implementation, the wireless terminal is configured, in conjunction
with the registration for the circuit switched (CS) service, to
refrain from performing a routing area update towards the Wide Band
Code Division Multiplexing (WCDMA) packet switched (PS) core
network.
[0037] In an example implementation, the wireless terminal is
configured to maintain the registration and/or session for a packet
switched (PS) service with the Long Term Evolution (LTE) core
network until such time as a circuit switched (CS) connection is
established, but to perform a routing area update towards the Wide
Band Code Division Multiplexing (WCDMA) packet switched (PS) core
network when a circuit switched (CS) connection is established.
[0038] In an example embodiment the wireless terminal comprises a
communication interface and a registration controller. The
communication interface is arranged to communicate, over the air
interface, a message configured to make the registration for the
circuit switched (CS) service. The registration controller is
configured to make the registration for the circuit switched (CS)
service over the Wide Band Code Division Multiplexing (WCDMA) air
interface with the circuit switched (CS) core network while
maintaining the registration and/or session for a packet switched
(PS) service with the Long Term Evolution (LTE) core network.
[0039] In another of its aspects the technology disclosed herein
concerns a method of operating a wireless terminal. The method
comprises the wireless terminal, when already having a registration
and/or session for a packet switched (PS) service with a Long Term
Evolution (LTE) core network, making a registration for a circuit
switched (CS) service over a Wide Band Code Division Multiplexing
(WCDMA) air interface with a circuit switched (CS) core network.
The method further comprises the wireless terminal maintaining the
registration and/or session for a packet switched (PS) service with
the Long Term Evolution (LTE) core network in conjunction with the
registration for the circuit switched (CS) service. In an example
mode and embodiment the wireless terminal refrains from making a
registration for a packet switched (PS) service over the Wide Band
Code Division Multiplexing (WCDMA) air interface with a packet
switched (PS) core network in conjunction with making the
registration for the circuit switched (CS) service over the Wide
Band Code Division Multiplexing (WCDMA) air interface with the
circuit switched (CS) core network. For example, in an example
implementation the wireless terminal method comprises the wireless
terminal refraining from performing a routing area update towards
the Wide Band Code Division Multiplexing (WCDMA) packet switched
(PS) core network in conjunction with the registration for the
circuit switched (CS) service.
[0040] In an example implementation the wireless terminal method
further comprises the wireless terminal refraining from performing
a routing area update towards the Wide Band Code Division
Multiplexing (WCDMA) packet switched (PS) core network in
conjunction with the registration for the circuit switched (CS)
service. In an example implementation the wireless terminal method
further comprises the wireless terminal performing a routing area
update towards the Wide Band Code Division Multiplexing (WCDMA)
packet switched (PS) core network when a circuit switched (CS)
connection is established.
[0041] In another of its aspects the technology disclosed herein
concerns a communications network comprising a Long Term Evolution
(LTE) core network; a circuit switched (CS) core network such as a
WCDMA network; and a wireless terminal. The wireless terminal is
configured, when already having a registration and/or session for a
packet switched (PS) service with the Long Term Evolution (LTE)
core network, to make a registration for a circuit switched (CS)
service over a Wide Band Code Division Multiplexing (WCDMA) air
interface with the circuit switched (CS) core network. The wireless
terminal is further configured to maintain the registration and/or
session for a packet switched (PS) service with the Long Term
Evolution (LTE) core network in conjunction with the registration
for the circuit switched (CS) service.
[0042] In another of its aspects the technology disclosed herein
concerns a method of operating such a communications network.
BRIEF DESCRIPTION OF THE DRAWINGS
[0043] The foregoing and other objects, features, and advantages of
the invention will be apparent from the following more particular
description of preferred embodiments as illustrated in the
accompanying drawings in which reference characters refer to the
same parts throughout the various views. The drawings are not
necessarily to scale, emphasis instead being placed upon
illustrating the principles of the invention.
[0044] FIG. 1A is a diagrammatic view illustrating a fully UE
centric solution ADM solution where no coordination is needed
between a GSM CS core and a LTE PS core.
[0045] FIG. 1B is a diagrammatic view illustrating a network
assisted ADM solution which can either be based on CS fallback
(CSFB), or a solution that only reuses paging over LTE.
[0046] FIG. 2A, FIG. 2B, and FIG. 2C are differing example
radio-realized embodiments illustrated of ADM solutions, with FIG.
2A showing an embodiment comprising a single receiver/transmitter
with GSM at half rate and multiplexing on a TDMA frame level; FIG.
2B showing an embodiment comprising a single receiver/transmitter
with multiplexing on a burst period level; and FIG. 2C showing an
embodiment comprising a dual receiver/single transmitter.
[0047] FIG. 3 is a diagrammatic view showing a packet switched-only
device in a Long Term Evolution (LTE) packet switched session.
[0048] FIG. 4 is a diagrammatic view showing a voice centric device
being registered in GSM with a Long Term Evolution (LTE) packet
switched session.
[0049] FIG. 5 is a diagrammatic view showing movement of a packet
switched session to WCDMA when being circuit switch registered in
WCDMA.
[0050] FIG. 6 is a diagrammatic view depicting basic acts or steps
involved in cell re-selection to WCDMA without use of a combined
location area and routing area update.
[0051] FIG. 7 is a diagrammatic view depicting basic acts or steps
involved in cell re-selection to WCDMA with use of a combined
location area and routing area update.
[0052] FIG. 8 is a diagrammatic view depicting a wireless terminal
participating in access division multiplexing (ADM) with a LTE
network and a WCDMA network.
[0053] FIG. 9 shows basic, representative acts or steps comprising
a method of operating wireless terminal according to an example
mode and embodiment.
[0054] FIG. 10 shows basic, representative acts or steps comprising
a method of operating wireless terminal according to a specific
implementation of the example mode and embodiment of FIG. 9.
[0055] FIG. 11 is a schematic view of an example embodiment of a
wireless terminal.
[0056] FIG. 12 is a more detailed schematic view of an example
embodiment of a wireless terminal showing a platform
implementation
[0057] FIG. 13 is a diagrammatic view depicting basic acts or steps
involved in cell re-selection to WCDMA without use of a combined
location area and routing area update and while maintaining a
packet switched registration and/or packet switched session in
LTE.
[0058] FIG. 14 is a diagrammatic view depicting basic acts or steps
involved in cell re-selection to WCDMA with use of a combined
location area and routing area update and while maintaining
registration and/or session for a packet switched service with the
Long Term Evolution (LTE) core network.
[0059] FIG. 15 is a diagrammatic view showing maintenance of a
packet switched (PS) registration and/or session in Long Term
Evolution (LTE) while being CS registered in WCDMA.
DETAILED DESCRIPTION
[0060] In the following description, for purposes of explanation
and not limitation, specific details are set forth such as
particular architectures, interfaces, techniques, etc. in order to
provide a thorough understanding of the present invention. However,
it will be apparent to those skilled in the art that the present
invention may be practiced in other embodiments that depart from
these specific details. That is, those skilled in the art will be
able to devise various arrangements which, although not explicitly
described or shown herein, embody the principles of the invention
and are included within its spirit and scope. In some instances,
detailed descriptions of well-known devices, circuits, and methods
are omitted so as not to obscure the description of the present
invention with unnecessary detail. All statements herein reciting
principles, aspects, and embodiments of the invention, as well as
specific examples thereof, are intended to encompass both
structural and functional equivalents thereof. Additionally, it is
intended that such equivalents include both currently known
equivalents as well as equivalents developed in the future, i.e.,
any elements developed that perform the same function, regardless
of structure.
[0061] Thus, for example, it will be appreciated by those skilled
in the art that block diagrams herein can represent conceptual
views of illustrative circuitry or other functional units embodying
the principles of the technology. Similarly, it will be appreciated
that any flow charts, state transition diagrams, pseudocode, and
the like represent various processes which may be substantially
represented in computer readable medium and so executed by a
computer or processor, whether or not such computer or processor is
explicitly shown.
[0062] The functions of the various elements including functional
blocks, including but not limited to those labeled or described as
"computer", "processor" or "controller", may be provided through
the use of hardware such as circuit hardware and/or hardware
capable of executing software in the form of coded instructions
stored on computer readable medium. Thus, such functions and
illustrated functional blocks are to be understood as being either
hardware-implemented and/or computer-implemented, and thus
machine-implemented.
[0063] In terms of hardware implementation, the functional blocks
may include or encompass, without limitation, digital signal
processor (DSP) hardware, reduced instruction set processor,
hardware (e.g., digital or analog) circuitry including but not
limited to application specific integrated circuit(s) [ASIC], and
(where appropriate) state machines capable of performing such
functions.
[0064] In terms of computer implementation, a computer is generally
understood to comprise one or more processors or one or more
controllers, and the terms computer and processor and controller
may be employed interchangeably herein. When provided by a computer
or processor or controller, the functions may be provided by a
single dedicated computer or processor or controller, by a single
shared computer or processor or controller, or by a plurality of
individual computers or processors or controllers, some of which
may be shared or distributed. Moreover, use of the term "processor"
or "controller" shall also be construed to refer to other hardware
capable of performing such functions and/or executing software,
such as the example hardware recited above.
[0065] In accordance with one aspect of the technology disclosed
herein illustrated by way of example in FIG. 8, a user equipment
unit (UE) or wireless terminal 30 can participate in access
division multiplexing (ADM) with two radio access technology
networks in parallel. FIG. 8 shows a cell of Long Term Evolution
(LTE) network 22-1 and a cell of WCDMA network 22-2 (a 3G network).
The LTE network 22-1 comprises a base station or eNodeB 28-1 while
the 3G network 22-2 comprises base station 28-2. As mentioned
above, the LTE network 22-1 does not provide circuit switched (CS)
services, so that a wireless terminal 30 participating in packet
switched (PS) services offered by LTE network 22-1 must turn to
another network, e.g., WCDMA network 22-2 for circuit switched (CS)
services.
[0066] The technology disclosed herein enables circuit switched
(CS) voice centric devices to benefit from the improved performance
of the Long Term Evolution (LTE) access as long as there is no CS
voice call ongoing. The solution is UE-centric which means that the
wireless terminal (e.g., user equipment unit [UE]) is registered
for CS services in WCDMA (in case WCDMA is the preferred access,
based on 3GPP compliant idle mode behavior). However, the wireless
terminal does not register for packet switched (PS) services in
WCDMA while being registered for CS services in WCDMA. This is done
by registering for CS services, while keeping the PS
registration/session in LTE.
[0067] The term "session" is used herein to indicate an active
packet switched (PS) connection, while the term "registration" is
used for a terminal which is known to the network, and thus a
terminal ready to have a "session" but not yet engaged in or
participating in a session. In Long Term Evolution (LTE) a
"registration" is performed initially as an "Attach" and maintained
(in Idle Mode) by "Tracking Area Updates". In Connected Mode, e.g.
while having a "session", the "registration" is maintained by
"being connected to the network". In WCDMA (and GSM) it is possible
to make a clearer distinction between "registration" and "session".
A "session" in WCDMA requires a PDP Context Activation to establish
the means of communication. On the other hand, in WCDMA a
registration can be made and maintained without a PDP Context being
activated.
[0068] FIG. 9 shows basic, representative acts or steps comprising
a method of operating wireless terminal 30 according to an example
mode and embodiment. Act 9-1 comprises the wireless terminal, when
already having a registration and/or session for a packet switched
(PS) service with a Long Term Evolution (LTE) core network, making
a registration for a circuit switched (CS) service over a Wide Band
Code Division Multiplexing (WCDMA) air interface with a circuit
switched (CS) core network. Act 9-2 comprises the wireless terminal
maintaining the registration and/or session for a packet switched
(PS) service with the Long Term Evolution (LTE) core network in
conjunction with the registration for the circuit switched (CS)
service. FIG. 10 shows a more specific mode and embodiment wherein
act 9-2 takes the form of act 9-2(10). Act 9-2(10) comprises the
wireless terminal refraining from making a registration for a
packet switched (PS) service over the Wide Band Code Division
Multiplexing (WCDMA) air interface with a packet switched (PS) core
network in conjunction with making the registration for the circuit
switched (CS) service over the Wide Band Code Division Multiplexing
(WCDMA) air interface with the circuit switched (CS) core network.
For example, in an example implementation below illustrated with
reference to FIG. 13 and FIG. 14, act 9-2(10) comprises the
wireless terminal refraining from performing a routing area update
towards the Wide Band Code Division Multiplexing (WCDMA) packet
switched (PS) core network in conjunction with the registration for
the circuit switched (CS) service.
[0069] FIG. 11 shows an example, generic, and basic embodiment of
wireless terminal 30. As shown in FIG. 11, wireless terminal 30
comprises communication interface 40 and service registration
controller 42. The communication interface 40 is arranged to engage
in communications over an air interface, such communications
including a message configured to make the registration for the
circuit switched (CS) service. The service registration controller
42 is configured to make the registration for the circuit switched
(CS) service over the Wide Band Code Division Multiplexing (WCDMA)
air interface with the circuit switched (CS) core network while
maintaining the registration and/or session for a packet switched
(PS) service with the Long Term Evolution (LTE) core network 22-1.
In the particular example embodiment illustrated in FIG. 11,
service registration controller 42 comprises routing area update
inhibitor 44.
[0070] FIG. 12 shows a more detailed example embodiment of wireless
terminal 30(12) comprising a first controller 58-1 configured to
handle administration and transmissions of LTE network 22-1 and
second controller 58-2 configured to handle administration and
transmissions of the WCDMA network 22-2. First controller 58-1 and
second controller 58-2 can be realized or implemented by a same
processor or controller (or processor system), and in such case may
constitute separate sets of non-transitory executable signals
(e.g., programs or routines stored on tangible media).
[0071] FIG. 12 further shows that certain functionalities of the
example wireless terminal 30(12) can be realized by and/or provided
on a platform 60. The terminology "platform" is a way of describing
how the functional units of a communications unit or node can be
implemented or realized by machine. One example platform is a
computer implementation wherein one or more of the elements framed
by line 60, including but not limited to service registration
controller 42.
[0072] In one example implementation, the functionalities shown as
framed by platform 60 and even other functionalities can be
realized by one or more processors which execute coded instructions
stored in memory (e.g., non-transitory signals) in order to perform
the various acts described herein. In such a computer
implementation the wireless terminal can comprise, in addition to a
processor(s), a memory section 62 (which in turn can comprise
random access memory 64; read only memory 66; application memory 68
(which stores, e.g., coded instructions which can be executed by
the processor to perform acts described herein); and any other
memory such as cache memory, for example).
[0073] Whether or not specifically illustrated, typically the
wireless terminal of each of the embodiments discussed herein can
also comprise certain input/output units or functionalities, the
representative input/output units for wireless terminal being
illustrated in FIG. 12 as keypad 70; audio input device (e.g.
microphone) 72; visual input device (e.g., camera) 74; visual
output device (e.g., display 76); and audio output device (e.g.,
speaker) 78. Other types of input/output devices can also be
connected to or comprise wireless terminal 30.
[0074] In the example of FIG. 12 the platform 60 has been
illustrated as computer-implemented or computer-based platform.
Another example platform 60 for wireless terminal can be that of a
hardware circuit, e.g., an application specific integrated circuit
(ASIC) wherein circuit elements are structured and operated to
perform the various acts described herein.
[0075] Furthermore, it will be appreciated that, as used herein,
"wireless terminal(s)" or "UE" can be mobile stations or user
equipment units (UE) such as but not limited to mobile telephones
("cellular" telephones) and laptops with wireless capability),
e.g., mobile termination), and thus can be, for example, portable,
pocket, hand-held, computer-included, or car-mounted mobile devices
which communicate voice and/or data with radio access network.
[0076] A method of keeping the PS registration/session in LTE while
registering for CS services is shown in FIG. 13 and FIG. 14. FIG.
13 shows Cell Re-selection to WCDMA where combined LA/RA Update is
not used and modifications are required; FIG. 14 shows Cell
Re-selection to WCDMA with combined LA/RA Update used and
modifications are required.
[0077] As shown in FIG. 13 and FIG. 14, the changes to the Cell
Re-selection to WCDMA include that there is no RA Update (or
combined LA/RA Update) towards the packet switched (PS) domain.
Refraining from a RA Update (or combined LA/RA Update) towards the
WCDMA packet switched (PS) domain enable the existing packet
switched (PS) session to be maintained in LTE while being CS
registered in WCDMA as shown in FIG. 15 (PS Session maintained in
LTE while being CS registered in WCDMA).
[0078] Once a circuit switched (CS) call is established, the
wireless terminal can perform a routing area update towards the
WCDMA PS Domain in conjunction with the CS call establishment. The
Registration Area (RA) Update can be sent before, after, or in
parallel with the CS call establishment. In other words, the
technology disclosed herein keeps the PS session in LTE while
CS-registered with WCDMA, but once a CS connection is established
the PS session in LTE is terminated.
[0079] As stated above, the RA Update can be sent before, after, or
in parallel with the CS call establishment. Preferably the RA
Update is sent as soon as possible after the CS call establishment.
The WCDMA packet switched (PS) service starts essentially
immediately after the routing area (RA) update.
[0080] An advantage of the technology disclosed herein is retaining
the better packet switched (PS) session via LTE (rather than
switching to WCMDA PS) during the period from WCDMA CS registration
to establishment of a CS call. This period from WCDMA CS
registration to establishment of a CS call can be a significant
time period, and thus the advantage can be considerable.
[0081] In the above regard, most people having a mobile phone are
engaged in calls only a small portion of the total connected time.
However, when considering smart phones like the iPhone, HTC Hero,
SonyEricsson Xperia X10, and the like, such phones are more or less
constantly connected in a packet switched (PS) session but rarely
in voice calls. A benefit of the technology disclosed herein is
thus that most of the time the better PS access will be retained
while being accessible for voice.
[0082] For wireless terminals camping on WCDMA where LTE coverage
is detected, the wireless terminal performs Tracking Area Update in
LTE, as defined in 3GPP TS 23.401, General Packet Radio Service
(GPRS) enhancements for Evolved Universal Terrestrial Radio Access
Network (E-UTRAN) access (Release 8) (chapter 5.3.3 for "54-SGSN"
to MME and Annex D.3.6 for "Gn/Gp SGSN to MME" Tracking Area
Update) (the contents of which are incorporated herein by
reference) but continues to listen for CS voice Paging in WCDMA
since it is still CS registered in WCDMA. When being connected in
WCDMA and detecting LTE coverage, the mobility management entity
(MME) is the network node that handles the Tracking Area Update, as
described in 3GPP TS 23.401.
[0083] Thus, with the technology disclosed herein, CS voice-enabled
devices can advantageously continue to use the packet switched (PS)
services over the LTE access while being circuit switched (CS)
registered in WCDMA.
[0084] Although the description above contains many specificities,
these should not be construed as limiting the scope of the
invention but as merely providing illustrations of some of the
presently preferred embodiments of this invention. Thus the scope
of this invention should be determined by the appended claims and
their legal equivalents. Therefore, it will be appreciated that the
scope of the present invention fully encompasses other embodiments
which may become obvious to those skilled in the art, and that the
scope of the present invention is accordingly to be limited by
nothing other than the appended claims, in which reference to an
element in the singular is not intended to mean "one and only one"
unless explicitly so stated, but rather "one or more." All
structural, chemical, and functional equivalents to the elements of
the above-described preferred embodiment that are known to those of
ordinary skill in the art are expressly incorporated herein by
reference and are intended to be encompassed by the present claims.
Moreover, it is not necessary for a device or method to address
each and every problem sought to be solved by the present
invention, for it to be encompassed by the present claims.
Furthermore, no element, component, or method step in the present
disclosure is intended to be dedicated to the public regardless of
whether the element, component, or method step is explicitly
recited in the claims. No claim element herein is to be construed
under the provisions of 35 U.S.C. 112, sixth paragraph, unless the
element is expressly recited using the phrase "means for."
* * * * *