U.S. patent application number 13/537568 was filed with the patent office on 2013-08-01 for centralized control of intra-cell device-to-device communication.
The applicant listed for this patent is Nageen Himayat, Kerstin Johnsson, Shilpa Talwar. Invention is credited to Nageen Himayat, Kerstin Johnsson, Shilpa Talwar.
Application Number | 20130195026 13/537568 |
Document ID | / |
Family ID | 48870112 |
Filed Date | 2013-08-01 |
United States Patent
Application |
20130195026 |
Kind Code |
A1 |
Johnsson; Kerstin ; et
al. |
August 1, 2013 |
CENTRALIZED CONTROL OF INTRA-CELL DEVICE-TO-DEVICE
COMMUNICATION
Abstract
An apparatus and method to centrally establish and control
intra-cell device-to-device connections on licensed bands of a
wireless communications network are disclosed herein. An eNodeB
receives a request from a first device to communicate with a second
device or a request from the first device for content or service.
The eNodeB schedules a device discovery between the first device
and at least a candidate device. The eNodeB determines establishing
the device-to-device connection between the first device and the
candidate device based on a discovery report generated by one of
the first or candidate device. The discovery report comprises
information about signal quality of transmission from the other one
of the first or candidate device that is received by the one of the
first or candidate device during the scheduled device
discovery.
Inventors: |
Johnsson; Kerstin; (Palo
Alto, CA) ; Himayat; Nageen; (Fremont, CA) ;
Talwar; Shilpa; (Los Altos, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Johnsson; Kerstin
Himayat; Nageen
Talwar; Shilpa |
Palo Alto
Fremont
Los Altos |
CA
CA
CA |
US
US
US |
|
|
Family ID: |
48870112 |
Appl. No.: |
13/537568 |
Filed: |
June 29, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61591641 |
Jan 27, 2012 |
|
|
|
Current U.S.
Class: |
370/329 |
Current CPC
Class: |
Y02D 70/162 20180101;
Y02D 70/22 20180101; H04B 7/0639 20130101; H04L 65/4076 20130101;
H04L 1/0027 20130101; Y02D 70/168 20180101; H04L 1/0026 20130101;
H04L 1/1896 20130101; H04L 5/005 20130101; H04W 52/0216 20130101;
H04W 72/04 20130101; Y02D 70/166 20180101; Y02D 70/1264 20180101;
Y02D 70/1242 20180101; Y02D 70/23 20180101; Y02D 70/21 20180101;
H04B 7/0617 20130101; H04B 7/024 20130101; H04L 1/1864 20130101;
H04B 7/0456 20130101; H04W 4/70 20180201; H04W 72/042 20130101;
Y02D 70/1224 20180101; H04L 65/608 20130101; H04W 76/27 20180201;
Y02D 70/1246 20180101; Y02D 70/144 20180101; H04L 5/1469 20130101;
H04L 27/2607 20130101; H04W 36/0094 20130101; H04W 72/085 20130101;
Y02D 70/442 20180101; H04L 1/1887 20130101; Y02D 70/24 20180101;
H04B 7/0413 20130101; H04L 5/0053 20130101; H04W 4/08 20130101;
H04B 1/69 20130101; H04W 72/082 20130101; Y02D 70/1222 20180101;
Y02D 70/142 20180101; H04L 12/189 20130101; H04W 72/0406 20130101;
Y02D 70/444 20180101; H04L 5/0035 20130101; Y02D 70/1262 20180101;
Y02D 70/1244 20180101; Y02D 70/146 20180101; H04B 7/0623 20130101;
H04L 1/0031 20130101; Y02D 30/70 20200801; Y02D 70/164 20180101;
H04W 72/044 20130101; H04W 72/0493 20130101; H04L 5/0048 20130101;
H04B 7/0626 20130101; H04W 48/16 20130101; H04W 76/28 20180201;
H04W 36/04 20130101 |
Class at
Publication: |
370/329 |
International
Class: |
H04W 72/08 20060101
H04W072/08 |
Claims
1. An enhanced node B (eNodeB) for controlling a device-to-device
connection on licensed bands of a wireless communications network,
the eNodeB comprising: a transceiver to receive a request from a
first device to communicate with a second device or a request from
the first device for content or service; a processor in
communication with the transceiver, the processor to schedule a
device discovery between the first device and at least a candidate
device and to determine establishing the device-to-device
connection between the first device and the candidate device based
on a discovery report generated by one of the first or candidate
device, wherein the discovery report comprises information about
signal quality of transmission from the other one of the first or
candidate device that is received by the one of the first or
candidate device during the scheduled device discovery.
2. The eNodeB of claim 1, wherein the processor determines
scheduling information to establish the device-to-device
connection, and wherein the transceiver transmits the scheduling
information to each of the first device and the candidate device to
establish the device-to-device connection.
3. The eNodeB of claim 1, wherein the candidate device is the
second device when the received request from the first device is to
communicate with the second device.
4. The eNodeB of claim 1, wherein the processor determines the at
least one candidate device based on proximity of the at least one
candidate device to the first device
5. The eNodeB of claim 1, wherein the processor determines that at
least one candidate device based on availability of the candidate
device to offer the content or service requested by the first
device.
6. The eNodeB of claim 5, wherein a memory in communication with
the processor includes information about the availability of
devices to offer the content or service requested by the first
device.
7. The eNodeB of claim 1, wherein the device discovery comprises a
first instruction to the other one of the first or candidate device
to transmit a specific message during the scheduled device
discovery and a second instruction to the one of the first or
candidate device to operate in a receive mode during the scheduled
device discovery.
8. The eNodeB of claim 7, wherein the device discovery comprises a
third instruction to the other one of the first or candidate device
to transmit information about the content or service requested and
a fourth instruction to the one of the first or candidate device to
confirm its availability of the content or service, when the
request received from the first device is for the content or
service, and wherein the other one of the first or candidate device
comprising the first device and the one of the first or candidate
device comprising the candidate device.
9. The eNodeB of claim 7, wherein the device discovery comprises a
third instruction to the other one of the first or candidate device
to include in the specific message content or service being offered
by the other one of the first or candidate device, when the request
received from the first device is for the content or service, and
wherein the other one of the first or candidate device comprises
the candidate device and the one of the first or candidate device
comprises the first device.
10. The eNodeB of claim 7, wherein the transceiver receives
availability information about the content or service automatically
from the candidate device without an instruction from the
eNodeB.
11. The eNodeB of claim 1, wherein the wireless communications
network comprises a 3rd Generation Partnership Project (3GPP) long
term evolution (LTE) network.
12. An enhanced node B (eNodeB), comprising: a transceiver to
receive a request from a first device to communicate with a second
device or a request from the first device for content or service; a
processor in communication with the transceiver, the processor to
schedule a device discovery between the first device and at least a
candidate device and to determine establishing the device-to-device
connection between the first device and the candidate device based
on a discovery report generated by one of the first or candidate
device, wherein the discovery report comprises information about
transmission signal quality during the scheduled device discovery,
and wherein both of the first device and the candidate device are
located within a cell served by the eNodeB.
13. The eNodeB of claim 12, wherein discovery report comprises
information about signal quality of transmission from the other one
of the first or candidate device as received by the one of the
first or candidate device during the scheduled device
discovery.
14. The eNodeB of claim 12, wherein the processor determines
whether to establish the device-to-device connection by selecting
among establishing a uni-directional device-to-device connection, a
bi-directional device-to-device connection, and device-to-base
connections.
15. The eNodeB of claim 12, wherein the scheduling information
comprises a connection identifier (CID) that is unique for the
device-to-device connection and at least one signaling parameter
for communicating on the device-to-device connection.
16. The eNodeB of claim 12, wherein the processor selects the at
least one candidate device from among a plurality of devices based
on a certain device-to-device range between the first device and
the candidate device.
17. The eNodeB of claim 12, wherein the processor monitors
performance of a session of the device-to-device connection after
the device-to-device connection has been established to schedule
subsequent communications between the first device and the
candidate device on the device-to-device connection.
18. The eNodeB of claim 12, wherein the candidate device is the
second device when the received request from the first device is to
communicate with the second device.
19. The eNodeB of claim 12, wherein the processor determines the at
least one candidate device based on proximity of the at least one
candidate device to the first device.
20. The eNodeB of claim 12, wherein the processor determines that
at least one candidate device based on availability of the
candidate device to offer the content or service requested by the
first device.
21. The eNodeB of claim 12, wherein each of the first device, the
second device, and the candidate device comprises a user equipment
(UE) operating in a 3rd Generation Partnership Project (3GPP) long
term evolution (LTE) network.
22. A method for controlling a device-to-device connection on
licensed bands of a wireless communications network including an
enhanced node B (eNodeB), the method comprising: receiving a
request from a first device to communicate with a second device;
scheduling, by the eNodeB, a device discovery between the first
device and the second device, the scheduling of the device
discovery including specifying one of the first or second device to
operate in transmit mode and the other one of the first or second
device to operate in receive mode during a device discovery time
period; receiving a discovery report from the other one of the
first or second device, the discovery report comprising information
about signal quality of a transmission from the one of the first or
second device as received by the other one of the first or second
device during the device discovery time period; and determining, by
the eNodeB, the device-to-device connection between the first and
second devices in accordance with the received discovery
report.
23. The method of claim 22, wherein the determining of the
device-to-device connection comprises selecting among establishing
a uni-directional device-to-device connection, a bi-directional
device-to-device connection, and device-to-base connections.
24. The method of claim 22, further comprising transmitting
scheduling information to each of the first and second devices to
establish the device-to-device connection.
25. The method of claim 24, wherein the scheduling information
comprises a connection identifier (CID) for the device-to-device
connection and at least one signaling parameter for communicating
on the device-to-device connection.
26. A computer readable medium including instructions, which when
executed by a processor of an enhanced node B (eNodeB), causes the
eNodeB to perform operations comprising: receiving a request from a
first device for content or service; scheduling a device discovery
between the first device and at least a second device, the
scheduling of the device discovery including specifying one of the
first or second device to operate in transmit mode and the other
one of the first or second device to operate in receive mode during
a device discovery time period; receiving a discovery report from
the other one of the first or second device, the discovery report
comprising information about signal quality of a transmission from
the one of the first or second device as received by the other one
of the first or second device during the device discovery time
period; and determining a device-to-device connection between the
first and second devices in accordance with the received discovery
report.
27. The computer readable medium of claim 26, further comprising
selecting the at least second device from among a plurality of
candidate devices based at least on a device-to-device range
between the first device and the second device, wherein both the
first device and the second device are intra-cell located with each
other.
28. The computer readable medium of claim 27, wherein the selecting
of the at least second device includes receiving information
relating to availability of the content or service requested at the
second device prior to scheduling the device discovery.
29. The computer readable medium of claim 26, wherein the
scheduling of the device discovery includes instructing the second
device to provide information relating to availability of the
content or service at the second device during the device discovery
time period.
30. The computer readable medium of claim 26, wherein the
scheduling of the device discovery includes instructing the first
device to transmit identification information corresponding to the
content or service requested during the device discovery time
period.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent
Application No. 61/591,641, entitled "Advanced Wireless
Communication Systems and Techniques" filed on Jan. 27, 2012, the
content of which is incorporated herein by reference in its
entirety.
TECHNICAL FIELD
[0002] The present disclosure relates generally to wireless
communications. More particularly, the present disclosure relates
to device-to-device communication on licensed bands.
BACKGROUND
[0003] With the influx of multi-media, gaming, and social web
services, increasing amounts of data traffic originates and
terminates at devices. When these devices are wireless devices and
operate within a licensed band radio access network (e.g., long
term evolution (LTE) network), the communication path comprises
wireless data transmission from an originating device to a base
station, possible data transfer along the core network, and another
wireless data transmission from a base station to a terminating
device. When the originating and terminating devices are in
relative close proximity to each other, however, such communication
path may be a waste of channel resources. Instead, a better use of
channel resources may be to enable direct communication between the
devices.
[0004] However because devices transmit omni-directionally, meaning
the transmission radiates circularly out in all directions, the
originating device attempting to directly communicate with the
terminating device may also inadvertently transmit to one or more
of the nearby devices. The resulting interference may be severe
enough that neither the terminating device nor the nearby device(s)
receive the transmissions they were intended to receive. Permitting
direct communication may in effect end up reducing network
efficiency rather than improving use of channel resources.
[0005] Even if interference associated with direct communication
between devices is minimal or otherwise managed, network operators
prefer to maintain control of use of its channel resources; not
just for quality of service (QoS) and interference management, but
also to accurately allocate data service charges for use of its
licensed bands.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 illustrates an example (portion) of a wireless
communications network according to some embodiments.
[0007] FIG. 2 illustrates an example block diagram showing details
of the base station (and devices) included in the wireless
communications network of FIG. 1 according to some embodiments.
[0008] FIGS. 3A-3B illustrate an example flow diagram for enabling
centralized control of intra-cell D2D communication on licensed
bands between devices associated with the same base station
according to some embodiments.
[0009] FIGS. 4A-4B illustrate example timing diagrams relating to
the flow diagram of FIGS. 3A-3B according to some embodiments.
DETAILED DESCRIPTION
[0010] The following description is presented to enable any person
skilled in the art to create and use a computer system
configuration and related method and article of manufacture to
centrally establish and control intra-cell device-to-device
connections on licensed bands of a wireless communications network.
In one embodiment, a first device requests communication with a
particular second device. The base station schedules device
discovery between the first and second devices when such devices
are within potential device-to-device range of each other. The
device discovery is operable for the second device to listen into
the first device's transmission and generate a report regarding the
signal quality of the transmission from the first device and/or
vice versa. The base station uses the report to determine whether
to establish a device-to-device link or conventional device-to-base
station links (between the first device and the base station and
between the second device and the base station). If a
device-to-device link is preferred, then the base station
determines a connection identifier for the particular connection
and other connection parameters, which are communicated to each of
the first and second devices to establish a device-to-device link
between the two devices.
[0011] In another embodiment, a first device requests certain
content or service but does not know which device(s) are offering
such content/service. The network determines one or more candidate
devices that can provide the requested content/service and are
within potential D2D range of the first device. A device discovery
is scheduled for each of the candidate devices to listen into the
first device's transmission and generate a report regarding the
signal quality of that transmission and/or vice versa. The report
from or about each of the candidate devices is used to select one
device from among the candidate devices and also to determine
whether to establish a device-to-device link or device-to-base
station links. If a device-to-device link is desired, a connection
identifier and other connection parameters are determined to
establish a device-to-device link between the first device and the
selected one of the devices from among the candidate devices.
[0012] Various modifications to the embodiments will be readily
apparent to those skilled in the art, and the generic principles
defined herein may be applied to other embodiments and applications
without departing from the scope of the invention. Moreover, in the
following description, numerous details are set forth for the
purpose of explanation. However, one of ordinary skill in the art
will realize that embodiments of the invention may be practiced
without the use of these specific details. In other instances,
well-known structures and processes are not shown in block diagram
form in order not to obscure the description of the embodiments of
the invention with unnecessary detail. Thus, the present disclosure
is not intended to be limited to the embodiments shown, but is to
be accorded the widest scope consistent with the principles and
features disclosed herein.
[0013] FIG. 1 illustrates an example (portion) of a wireless
communications network 100 according to some embodiments. In one
embodiment, the wireless communications network 100 comprises an
evolved universal terrestrial radio access network (EUTRAN) using
the 3rd Generation Partnership Project (3GPP) long term evolution
(LTE) standard operating in time division duplex (TDD) mode or
frequency division duplex (FDD) mode. In another embodiment, the
wireless communications network 100 comprises a WiMax network, a
code division multiple access (CDMA) network, a global system for
mobile communication (GSM) network, or a variety of other licensed
band networks.
[0014] The wireless communications network 100 includes a base
station 102 and a plurality of devices 106, 108, 109. The base
station 102 (also referred to as BS or an enhanced Node B (eNodeB
or eNB)) is configured to serve a certain geographic area, denoted
as a cell 104. The plurality of devices 106, 108, 109 located
within the cell 104 are served by the base station 102. The base
station 102 is configured to communicate with each of the plurality
of devices 106, 108, 109 on a first carrier frequency and
optionally, one or more secondary carrier frequencies. For ease of
illustration, only a single base station is shown in FIG. 1.
However, it is understood that the wireless communications network
100 includes more than one base station, each of the base stations
serving a particular cell which may or may not neighbor the base
station 102.
[0015] The plurality of devices 106, 108, 109 (also referred to as
user equipments (UEs)) may comprise a variety of devices configured
to communicate within the wireless communications network 100
including, but not limited to, cellular telephones, smart phones,
tablets, laptops, desktops, personal computers, servers, personal
digital assistants (PDAs), web appliances, set-top box (STB), a
network router, switch or bridge, and the like. The plurality of
devices 106, 108, 109 comprises a first device 106, a second device
108, and a third device 109. One or more of the devices 106, 108,
109 may move into or out of the cell 104 at any given time. Less or
more than three devices may be served by the base station 102 at
any given time.
[0016] In one embodiment, the devices 106, 108, 109 located within
the cell 104 transmit data to the base station 102 (uplink
transmission) and receive data from the base station 102 (downlink
transmission) using radio frames. Each radio frame comprises a
plurality of uplink and downlink subframes, the uplink and downlink
subframes configured in accordance with the uplink-downlink ratio
configuration selected by the base station 102 from among the
supported uplink-downlink ratio configurations. An example set of
supported uplink-downlink ratio configurations are provided in 3GPP
TS 36.211Version 9.1.0, E-UTRA Physical Channels and Modulation
(Release 9), March 2010 for 3GPP LTE networks.
[0017] When the first device 106 wishes to communicate with the
second device 108, the conventional communication process is as
follows: data is transmitted from the first device 106 to the base
station 102 along a first conventional path 110a ; next the data is
passed to the core network for processing and back to the base
station 102 (unless local switching at the base station 102 is
enabled); and finally, the base station 102 relays the data (with
possible processing) to the second device 108 along a second
conventional path 110b. The transmission rate at each leg of the
communication pathway, for example, may be 4 megabit per second
(Mbps) for the first conventional path 110a and 24 Mbps for the
second conventional 110b. Thus, the 4 Mbps rate on the first
portion of the communication pathway limits the overall data rate
from the first device 106 to the second device 108 via the base
station 102. Conversely, the conventional communication pathway
from the second device 108 to the first device 106 via the base
station 102 comprises a first conventional path 112a between the
second device 108 and base station 102, and a second conventional
path 112b between the base station 102 and the first device 106.
Continuing the example, the transmission rate associated with each
of the first and second conventional paths 112a, 112b can be 24
Mbps.
[0018] If the first and second devices 106, 108 were to directly
communicate with each other (e.g., without the data passing via the
base station 102), then a direct communication path 114 can be
defined between the first and second devices 106, 108. Continuing
the example, the transmission rate associated with the direct
communication path 114 can be 10 Mbps. Thus, data transmission from
the first device 106 to the second device 108 should be sent on the
direct communication path 114 (at 10 Mbps) instead of via the base
station 102 (limited at 4 Mbps for the first conventional path 110a
). However, the rate from the second device 108 to the first device
106 is higher via the base station 102 (at 24 Mbps) rather than the
direct communication path 114 (at 10 Mbps). As such the
communication flowing in this direction should be via the base
station 102. The wireless communications network 100 determines the
best data transmission pathway based on optimization of data rates
along with a number of the factors, as described in detail
below.
[0019] FIG. 2 illustrates an example block diagram showing details
of the base station 102 according to some embodiments. The base
station 102 includes a processor 202, a memory 204, a transceiver
206, instructions 208, and other components (not shown). The
processor 202 comprises one or more central processing units
(CPUs), graphics processing units (GPUs), or both. The processor
202 is configured to provide processing and control functionalities
for the base station 102. The memory 204 comprises one or more
transient and static memory units configured to store instructions,
data, setting information, and the like for the base station 102.
The transceiver 206 comprises one or more transceivers configured
to receive uplink receptions and transmit downlink transmissions
with the devices 106, 108, 109 within range of the base station
102. The transceiver 206 includes a multiple-input and
multiple-output (MIMO) antenna to support MIMO communications.
[0020] The instructions 208 comprises one or more sets of
instructions or software executed on a computing device (or
machine) to cause such computing device (or machine) to perform any
of the methodologies discussed herein. The instructions 208 (also
referred to as computer- or machine-readable instructions) may
reside, completely or at least partially, within the processor 202
and/or memory 204 during execution thereof. The processor 202 and
memory 204 also comprise machine-readable media. In one embodiment,
the processor 202 executes the instructions 208 to enable
centralized control of device-to-device (D2D) communication on
licensed bands between the plurality of devices served by the base
station 102.
[0021] One or more of the components described above for the base
station 102 may also be included in each of the plurality of
devices served by the base station 102. To the extent that any of
the devices performs functionalities or operations similar to that
performed by the base station 102, such functionalities or
operations may be implemented using hardware, firmware, and/or
software similar to that included in the base station 102.
[0022] FIGS. 3A-3B illustrate an example flow diagram 300 for
enabling centralized control of intra-cell D2D communication on
licensed bands between devices associated with a given base station
according to some embodiments. FIGS. 4A-4B illustrate example
timing diagrams relating to the flow diagram 300 according to some
embodiments. FIGS. 3A-3B are described below in conjunction with
FIGS. 4A-4B.
[0023] As discussed in detail below, the base station (e.g., base
station 102) determines whether D2D communication is better use of
network resources over conventional communication via the base
station. If D2D communication is preferable (either uni-directional
or bi-directional), the base station authorizes and establishes a
secure D2D connection and schedules all D2D communications between
the pair of devices. In this manner, the base station manages reuse
of licensed band resources on D2D and device-to-base station (D2B)
links, and maintains control of quality of service (QoS),
interference, traffic loading, and other service parameters within
its cell (e.g., cell 104).
[0024] In one embodiment, FIGS. 3A and 4A show a first protocol
where the originating (e.g., first device 106) and terminating
devices (e.g., second device 108) are already known to the wireless
communications network 100 at the time of a communication request.
At a block 302 of FIG. 3A, the base station 102 receives a request
from the first device 106 (also referred to as D1) to communicate
with a specific device, such as the second device 108 (also
referred to as D2) (communication 402 in FIG. 4A).
[0025] In response to the received request, the base station 102 at
a block 304 determines whether the first and second devices 106,
108 are within the cell 104 and within D2D range of each other. If
the first and second devices 106, 108 currently have an on-going
session with each other, the base station 102 schedules a device
discovery period for these devices upon occurrence of a pre-defined
event. The pre-defined event (also referred to as a network-defined
trigger) can be one or more events. As an example, the pre-defined
event can be when the second device 108 performs handover to the
same base station that the first device 106 is associated with. If
the first and second devices 106, 108 do not currently enjoy an
established session with each other, the wireless communications
network 100 (or the base station 102) automatically or in response
to the presence of a pre-defined event checks whether the first and
second devices 106, 108 are within D2D range of each other before
establishing their session over traditional infrastructure (e.g.,
D2B) links. Example checks for sufficiency of D2D range includes
checking if both the first and second devices 106, 108 are
associated with the same base station (e.g., base station 102),
obtaining geo-location information about each of the first and
second devices 106, 108 (e.g., global positioning satellite (GPS)
locations), and the like.
[0026] Next at a block 306, once condition(s) are satisfied to
initiate a device discovery period, the base station 102 schedules
a device discovery resource allocation during which the second
device 108 listens for a transmission from the first device 106
(communication 404). While the remainder of this discussion is
based on the foregoing division of device discovery roles, it is
understood that the base station 102 can just as easily assign the
first device 106 to listen while the second device 108 transmits,
or assign the two devices different roles during different parts of
the discovery period. The base station 102 can also assign an
ad-hoc discovery period where the devices randomly transmit and
listen (similar to WiFi discovery). The allocation structure
includes instructions for the first device 106 to transmit a
specific message, the specific message comprising data that would
be typically transmitted to the base station 102 to establish a
connection, a specific advertisement message, a specific pilot
message, a data ping, or any other information (collectively
referred to as a discovery message). The allocation structure also
includes instructions to the second device 108 to listen during the
resource allocation time period and possibly what to listen for. In
some respect the first device 106 transmits data during resource
allocation as it normally would to communicate with the base
station 102. The first device 106 may not be aware that it is
necessarily transmitting data to be overheard by the second device
108.
[0027] In the case of the wireless communications network 100
being, for example, a 3GPP LTE network, the base station 102
controls data traffic within its cell 104 via selection of a
particular uplink-downlink ratio configuration. The devices
associated with the base station 102 all switch to a transmit mode
or a receive mode at each respective time period in accordance with
the particular uplink-downlink ratio configuration. During the
scheduled device discovery resource allocation, the first device
106 operates in transmit mode (as it normally would in accordance
with the particular uplink-downlink ratio configuration), but the
second device 108 is instructed to switch to receive mode (in
contradiction of the particular uplink-downlink ratio
configuration) for at least part of that uplink time period.
[0028] Moreover, for a 3GPP LTE network operating in TDD mode, the
downlink and uplink are performed on the same frequency band and
thus a single scheduled device discovery is sufficient to evaluate
D2D channel quality regardless of whether it is scheduled during
the uplink or downlink. For a 3GPP LTE network operating in FDD
mode, the downlink and uplink are performed using different
frequencies. Accordingly, if the D2D link is to be scheduled during
both the uplink and downlink, the base station 102 schedules at
least two device discovery resource allocations, one for the
downlink frequencies and the other for the uplink frequencies.
[0029] At a block 308, the base station 102 receives a discovery
message transmitted by the first device 106 in accordance with the
scheduled device discovery resource allocation (communication 406).
If the second device 108 successfully receives (overhears) this
discovery message from the first device 106 during device discovery
allocation, then the second device 108 is able to discern signal
quality, channel quality, channel information, and other
characteristics relating to receipt of a transmission from the
first device 106 (collectively referred to as a device discovery
report). The second device 108 sends the device discovery report to
the base station 102 (communication 408), and the base station 102
correspondingly receives such device discovery report at a block
310.
[0030] Based on the device discovery report received from the
second device 108, the base station 102 determines whether a
uni-directional D2D link, a bi-directional D2D link, or D2B links
(e.g., no D2D link) would be best at a block 312. The base station
102 considers a number of factors including, but not limited to,
channel qualities, required QoS, traffic loads, potential
interference, and the like.
[0031] A D2D connection can increase network capacity by: (1)
increasing and optimizing channel reuse, (2) boosting transmission
data rates between the first and second devices 106, 108, and (3)
reducing the number of transmissions (segments). Increased channel
reuse is a result of D2D links being significantly shorter in range
and closer to the ground than most D2B links. The shorter range may
enable higher data rates at lower transmit powers, since not only
is the propagation path shorter, but shadowing and/or interference
is often less. The shorter distance from the ground improves signal
isolation from other D2D connections as well as standard D2B
connections (e.g., they can reuse the same spectrum with acceptable
interference levels). Because the base station controls scheduling
on both D2D and D2B links, it can use appropriate protocols (e.g.,
dynamic base station scheduling, MIMO-based interference
management, super-position coding, etc.) to optimize reuse of
heavily-loaded licensed bands. D2D connections also reduce the
number of transmissions by replacing the conventional two-hop path
(originating device to base station, through the core network, and
then base station to terminating device) with a one-hop path
between a given pair of devices.
[0032] If the base station 102 determines that a D2D link between
the first and second devices 106, 108 is not preferable ("no"
branch of block 314), then the base station 102 communicates with
the first device 106 and the second device 108 to establish
standard D2B links (block 316). Otherwise the base station 102 has
determined that a uni-directional or bi-directional D2D link should
be established ("yes" branch of block 314), and the base station
102 determines various connection parameters to establish a D2D
connection between the first and second devices 106, 108 (block
318). If the D2D link is uni-directional but the traffic between
the first and second devices 106, 108 is bi-directional, the base
station 102 also establishes D2B links with both devices for the
non-D2D traffic direction.
[0033] At the block 318, the base station 318 determines or
configures the appropriate connection identifiers (CIDs), security
context (and potentially re-authenticates the devices), optimal
transmission power level, modulation/coding level, and other
connection parameters (collectively referred to as D2D connection
scheduling information or message) to establish the desired D2D
connection. For example, the transmission power level can be lower
for a device to transmit to a nearby device than to transmit to a
base station. Optimizing the power level decreases interference
potential and extends the battery life of the devices. Depending on
the network standard, the base station 102 may create a distinct
CID for each desired D2D traffic direction or just a single CID for
both traffic directions of the D2D link. In the case where a single
CID is used for both traffic directions of the D2D link, when the
scheduling mechanism allocates bandwidth to the D2D CID, the
scheduling mechanism also specifies which device has "transmit
rights" for a given point in time. Such D2D connection scheduling
information is transmitted (multi-cast) to each of the first and
second devices 106, 108 at a block 320 (communication 410).
[0034] Then at a block 322, the base station 102 receives a
confirmation that a D2D connection has been established from each
of the first and second devices 106, 108 (communication 412).
Lastly at a block 324, since the base station 102 controls and
schedules each communication between the first and second devices
106, 108 on the established D2D link, the base station 102 receives
and monitors information about channel quality, QoS, traffic loads,
interference information, link data rate, link performance
characteristics, etc. pertaining to the D2D link to set the
scheduling parameters (e.g., optimal power level, modulation/coding
level, schedule resources) associated with the next bandwidth
request from the first or second devices 106, 108. Depending on the
monitored performance characteristics, the base station 102 can
decide to move the data traffic back to the infrastructure path
when necessary.
[0035] On future bandwidth requests associated with a specific D2D
CID, the base station 102 uses the D2D CID to assign channel
resources in the scheduling map/message. The base station 102 uses
channel quality, QoS, traffic load, and interference information
about the D2D link to set the optimal power, modulation/coding
level, and schedule resources to optimize network performance.
[0036] In another embodiment, FIGS. 3A, 3B, and 4B show a second
protocol in which the originating device (e.g., first device 106)
only knows the content or service it wants but not which device it
wants to connect to. At the block 302, the base station 102
receives a request from the first device 106 for data content or
service (communication 420 of FIG. 4B). FIG. 3B shows sub-blocks of
block 302, in which the base station 102 receives the request for
data content or service from the first device 106 (sub-block 330)
and then determines potential device(s) that can supply the
requested data content or service (sub-block 332).
[0037] At the sub-block 332 and block 304, if the network 100
maintains (or has access to) a database of data content and/or
services offered by its subscribers' devices, then the network 100
(or base station 102) determines which device(s) that are located
within the cell 104 offer the content/service requested by the
first device 106. If the network 100 (or base station 102) has more
specific location information (such as GPS coordinates) about the
devices within the cell 104, then only those device(s) that are
within potential D2D range of the first device 106 and which offer
the content/service requested by the first device 106, in
accordance with the database, may be selected. Alternatively, the
network 100 (or base station 102) may choose to expand the group of
eligible devices beyond those identified by the database. In some
embodiments, the database may be included in the base station 102,
such as the memory 204 (FIG. 2).
[0038] If the network 100 does not maintain (or have access to)
such a database, then the network 100 (or base station 102) can at
least identify the device(s) that are within D2D range of the first
device 106 (e.g., based association with the same base station or
on more specific location information such as GPS data), and then
inquire with those device(s) whether they offer the requested
content/server. If the base station 102 plans to schedule an ad-hoc
discovery period, then it can bypass this inquiry and instead
request that only devices with the requested content/service engage
in discovery with the first device 106. For instance, the devices
identified as candidates for a D2D connection with the first device
106 to provide the requested content/service can be each of the
second device 108 and the third device 109 (also referred to as
D3). One or more devices can be identified as candidate
devices.
[0039] Next at the block 306, the base station 102 schedules device
discovery resource allocation with each of the first device 106 and
all of the devices identified as candidates for a D2D connection
(e.g., second and third devices 108, 109) similar to that discussed
above with respect to the first protocol (communication 422). The
allocation structure instructs the first device 106 to transmit a
specific discovery message, and instructs each of the second and
third devices 108, 109 to listen in during the first device's 106
transmission time period. As previously noted above, while in this
discussion the first device 106 is assigned to transmit the
discovery message and the second and third devices 108, 109 are
assigned to listen for the discovery message and report the results
to the base station 102, the base station 102 can conversely or
also schedule the second and third devices 108, 109 to transmit
discovery messages and the first device 106 to listen for such
discovery messages, or the base station 102 may schedule an ad-hoc
discovery period.
[0040] In some embodiments, the first device 106 can be further
instructed to include in its discovery message information about
the requested data content/service so that devices that
successfully receive the discovery message during the device
discovery allocation time period can confirm that they have
available the requested content/service. The first device 106 can
also include this information autonomously. Inclusion of
information about the requested data content/service in the
discovery message may be useful, for example, when there is no
available database cataloging the devices' content/service
offerings. If the base station 102 schedules the second and/or
third devices 108, 109 to transmit the discovery message, each of
these devices may transmit its content/service offering.
[0041] If the network 100 (or base station 102) chooses to expand
the group of candidate devices for D2D connection beyond those
identified using the database, this may increase the number of
candidate devices significantly. As such, these devices may be
grouped and identified according to different criteria (e.g.,
sector, GPS location, signal strength, etc.) in order to reduce
signaling overhead in the allocation structure when scheduling an
ad-hoc discovery period.
[0042] Once device discovery is scheduled, at the block 308, the
first device 106 transmits a specific discovery message and such
discovery message is received by the base station 102 similar to
that discussed above with respect to the first protocol
(communication 424). Each of the candidate devices scheduled to
participate in the device discovery, and which successfully
received (overhead) the discovery message transmitted by the first
device 106, sends a device discovery report to the base station
102. The respective device discovery reports are received by the
base station 102 at the block 308 similar to that discussed above
with respect to the first protocol. Continuing the example, the
base station receives a device discovery report from each of the
second and third devices 108, 109 (communication 426). The base
station 102 may stop transmission of these reports if or when it
determines that it has already found a viable D2D candidate from
those already received. The device discovery report includes
information about the signal quality, channel quality, and other
characteristics of the transmission from the first device 106. If
the discovery message includes information about the requested
content/service, the device discovery report from each of the
devices also confirms the availability of the requested
content/service on the respective device. If the base station 102
instead schedules the second the third devices 108, 109 to transmit
the discovery message and the first device 106 to listen, the first
device 106 may analyze/process the discovery information and filter
the list of potential candidates before sending a discovery report
to the base station 102.
[0043] Next at the block 312, the base station 102 determines which
device from among the candidate devices should provide the
requested content/service and what kind of communication path
should be established to accomplish the content/service "download"
(uni-directional D2D link, bi-directional D2D link, D2B links)
based on the received device discovery reports. Note that even
though the original request for content/service "download" is from
the selected device to the first device 106, the base station 102
determines the best communication path for both directions of data
traffic, because the first device 106 may subsequently respond to
the content/service source. As discussed above with respect to the
first protocol, the base station 102 considers channel qualities,
traffic load, QoS, and the like reported (or determined from the
report) from or about each of the candidate devices to select the
content/service source device and communication path.
[0044] Continuing the example, the base station 102 may select the
third device 109 (from among the second and third devices 108, 109)
to be the content/service source to fulfill the first device's
request.
[0045] The remaining blocks 314-324 are performed the same as
discussed above except the blocks are performed with respect to the
first device 106 and the selected device (continuing the example,
the third device 109). Among other things, the base station 102
communicates scheduling information to each of the first and third
devices, 106, 109 (communication 428) to setup or establish a D2D
connection there between at the block 320. In response, the base
station 102 receives confirmation of establishment of the D2D
connection from each of the first and third devices 106, 109
(communication 430) at the block 322.
[0046] Once a D2D link has been established between a given pair of
devices--for both cases where the requesting and terminating
devices are known at the onset and for when only the requesting
device is known--the majority of the control signaling passes
between the base station and the given pair of devices. The D2D
link is primarily used for data traffic. In some embodiments,
however, certain of the control signaling may pass between the
given pair of devices without involving the base station. For
example, the network may determine that it is a more efficient use
of network resources for packet acknowledgements, ACK/NACKs, to
pass directly between the given pair of devices.
[0047] Accordingly, centralized control of intra-cell D2D
connections on licensed bands is disclosed herein. The wireless
communications network boosts network capacity by judiciously
moving data traffic off the infrastructure network onto direct
communication links between devices. Such use of D2D links
increases channel reuse, improves data rates, and reduces the
number of transmissions. Moreover, because this mechanism is fully
centralized--controlled and scheduled by the network--the network
operator maintains full oversight of D2D links. The network
operator thus maintains control of network resources and network
performance as well as pricing/charging rights.
[0048] The term "machine-readable medium," "computer readable
medium," and the like should be taken to include a single medium or
multiple media (e.g., a centralized or distributed database, and/or
associated caches and servers) that store the one or more sets of
instructions. The term "machine-readable medium" shall also be
taken to include any medium that is capable of storing, encoding or
carrying a set of instructions for execution by the machine and
that cause the machine to perform any one or more of the
methodologies of the present disclosure. The term "machine-readable
medium" shall accordingly be taken to include, but not be limited
to, solid-state memories, optical and magnetic media,
non-transitory, and carrier wave signals.
[0049] It will be appreciated that, for clarity purposes, the above
description describes some embodiments with reference to different
functional units or processors. However, it will be apparent that
any suitable distribution of functionality between different
functional units, processors or domains may be used without
detracting from embodiments of the invention. For example,
functionality illustrated to be performed by separate processors or
controllers may be performed by the same processor or controller.
Hence, references to specific functional units are only to be seen
as references to suitable means for providing the described
functionality, rather than indicative of a strict logical or
physical structure or organization.
[0050] Although the present invention has been described in
connection with some embodiments, it is not intended to be limited
to the specific form set forth herein. One skilled in the art would
recognize that various features of the described embodiments may be
combined in accordance with the invention. Moreover, it will be
appreciated that various modifications and alterations may be made
by those skilled in the art without departing from the scope of the
invention.
[0051] The Abstract is provided to allow the reader to quickly
ascertain the nature of the technical disclosure. It is submitted
with the understanding that it will not be used to interpret or
limit the scope or meaning of the claims. In addition, in the
foregoing Detailed Description, it can be seen that various
features are grouped together in a single embodiment for the
purpose of streamlining the disclosure. This method of disclosure
is not to be interpreted as reflecting an intention that the
claimed embodiments require more features than are expressly
recited in each claim. Rather, as the following claims reflect,
inventive subject matter lies in less than all features of a single
disclosed embodiment. Thus the following claims are hereby
incorporated into the Detailed Description, with each claim
standing on its own as a separate embodiment.
* * * * *