U.S. patent application number 17/086223 was filed with the patent office on 2021-02-18 for mac subheader for d2d broadcast communication for public safety.
The applicant listed for this patent is QUALCOMM Incorporated. Invention is credited to Sudhir Kumar BAGHEL.
Application Number | 20210051626 17/086223 |
Document ID | / |
Family ID | 1000005190802 |
Filed Date | 2021-02-18 |
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United States Patent
Application |
20210051626 |
Kind Code |
A1 |
BAGHEL; Sudhir Kumar |
February 18, 2021 |
MAC SUBHEADER FOR D2D BROADCAST COMMUNICATION FOR PUBLIC SAFETY
Abstract
A method, an apparatus, and a computer program product for
wireless communication are provided. The apparatus configures at
least a non-access stratum (NAS) protocol layer or a radio resource
control (RRC) protocol layer to enable device-to-device (D2D)
communication with at least a second apparatus when the apparatus
is out of network coverage, and communicates with at least the
second apparatus.
Inventors: |
BAGHEL; Sudhir Kumar;
(Hillsborough, NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporated |
San Diego |
CA |
US |
|
|
Family ID: |
1000005190802 |
Appl. No.: |
17/086223 |
Filed: |
October 30, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16144773 |
Sep 27, 2018 |
10849101 |
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17086223 |
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14483962 |
Sep 11, 2014 |
10117224 |
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16144773 |
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61880792 |
Sep 20, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 4/08 20130101; H04W
76/40 20180201; H04W 4/06 20130101; H04W 88/04 20130101; H04W 72/00
20130101; H04W 72/005 20130101; H04W 92/18 20130101; H04W 76/14
20180201; H04W 28/06 20130101 |
International
Class: |
H04W 72/00 20060101
H04W072/00; H04W 76/14 20060101 H04W076/14; H04W 4/06 20060101
H04W004/06 |
Claims
1. A method of wireless communication for a first user equipment
(UE), comprising: determining that an application associated with
public safety is initiated; configuring a radio resource control
(RRC) protocol layer for device-to-device (D2D) broadcast
communication based on initiation of the application associated
with public safety; configuring one or more protocol layers for
broadcast operation based on configuring the RRC protocol layer for
the D2D broadcast communication, the one or more protocol layers
being lower than the RRC protocol layer; and communicating with at
least a second UE based on the one or more protocol layers being
configured for the broadcast operation.
2. The method of claim 1, further comprising: configuring a
non-access stratum (NAS) protocol layer based on the initiation of
the application associated with public safety, wherein the RRC
protocol layer is configured for the D2D broadcast communication
based on the NAS protocol layer being configured.
3. The method of claim 2, wherein the configuring the NAS protocol
layer comprises: setting at least an Internet Protocol (IP) address
for the first UE, a priority for the first UE when the first UE
belongs to a D2D communication group, or an IP multicast address
when the first UE belongs to the D2D communication group.
4. The method of claim 1, further comprising: configuring at least
a bearer for the D2D broadcast communication.
5. The method of claim 1, wherein the one or more protocol layers
lower than the RRC protocol layer comprises at least one of a
packet data convergence protocol (PDCP) layer, an radio link
control (RLC) layer, a medium access control (MAC) layer, or a
physical layer.
6. The method of claim 5, wherein configuring the one or more
protocol layers for the broadcast operation based on configuring
the RRC protocol layer for the D2D broadcast communication
comprises: configuring at least one of the PDCP layer or the RLC
layer to operate in a unidirectional mode (U-Mode).
7. The method of claim 5, wherein configuring the one or more
protocol layers for the broadcast operation based on configuring
the RRC protocol layer for the D2D broadcast communication
comprises: configuring the MAC layer to generate a MAC subheader,
the MAC subheader comprising at least a session identification
(ID), a group ID that indicates a D2D communication group to which
the first UE belongs, or a source ID that indicates an ID
associated with the first UE.
8. The method of claim 7, wherein the MAC subheader further
comprises duplicate packet identification information.
9. The method of claim 7, wherein the MAC subheader further
comprises at least one of a priority of a session or a time
interval for which a lower priority session should not start.
10. The method of claim 1, wherein configuring the one or more
protocol layers for the broadcast operation based on configuring
the RRC protocol layer for the D2D broadcast communication
comprises: configuring a medium access control (MAC) layer to
generate a MAC control element (CE) comprising at least a group
identification (ID) that indicates a D2D communication group to
which the first UE belongs, a source ID that indicates an ID
associated with the first UE, a priority of a session, or a time
interval for which a lower priority session should not start.
11. The method of claim 10, wherein communicating with the at least
the second UE based on the one or more protocol layers being
configured for the broadcast operation comprises: transmitting, to
the at least the second UE, a message including the MAC CE
indicating that the first UE will send a transmission.
12. The method of claim 1, further comprising: monitoring one or
more radio resources for an announcement from the at least the
second UE, the second UE belonging to a D2D communication group of
interest.
13. An apparatus of wireless communication by a first user
equipment (UE), comprising: means for determining that an
application associated with public safety is initiated; means for
configuring a radio resource control (RRC) protocol layer for
device-to-device (D2D) broadcast communication based on initiation
of the application associated with public safety; means for
configuring one or more protocol layers for broadcast operation
based on configuring the RRC protocol layer for the D2D broadcast
communication, the one or more protocol layers being lower than the
RRC protocol layer; and means for communicating with at least a
second UE based on the one or more protocol layers being configured
for the broadcast operation.
14. The apparatus of claim 13, further comprising: means for
configuring a non-access stratum (NAS) protocol layer based on the
initiation of the application associated with public safety,
wherein the RRC protocol layer is configured for the D2D broadcast
communication based on the NAS protocol layer being configured.
15. The apparatus of claim 14, wherein the means for configuring
the NAS protocol layer is configured to set at least an Internet
Protocol (IP) address for the first UE, a priority for the first UE
when the first UE belongs to a D2D communication group, or an IP
multicast address when the first UE belongs to the D2D
communication group.
16. The apparatus of claim 13, further comprising: means for
configuring at least a bearer for the D2D broadcast
communication.
17. The apparatus of claim 13, wherein the one or more protocol
layers lower than the RRC protocol layer comprises at least one of
a packet data convergence protocol (PDCP) layer, an radio link
control (RLC) layer, a medium access control (MAC) layer, or a
physical layer.
18. The apparatus of claim 17, wherein means for configuring the
one or more protocol layers for broadcast operation based on
configuring the RRC protocol layer for the D2D broadcast
communication is configured to configure at least one of the PDCP
layer or the RLC layer to operate in a unidirectional mode
(U-Mode).
19. The apparatus of claim 17, wherein means for configuring the
one or more protocol layers for the broadcast operation based on
configuring the RRC protocol layer for the D2D broadcast
communication is configured to configure the MAC layer to generate
a MAC subheader, the MAC subheader comprising at least a session
identification (ID), a group ID that indicates a D2D communication
group to which the first UE belongs, or a source ID that indicates
an ID associated with the first UE.
20. The apparatus of claim 19, wherein the MAC subheader further
comprises duplicate packet identification information.
21. The apparatus of claim 19, wherein the MAC subheader further
comprises at least one of a priority of a session or a time
interval for which a lower priority session should not start.
22. The apparatus of claim 13, wherein means for configuring the
one or more protocol layers for the broadcast operation based on
configuring the RRC protocol layer for the D2D broadcast
communication is configured to configure a medium access control
(MAC) layer to generate a MAC control element (CE) comprising at
least a group identification (ID) that indicates a D2D
communication group to which the first UE belongs, a source ID that
indicates an ID associated with the first UE, a priority of a
session, or a time interval for which a lower priority session
should not start.
23. The apparatus of claim 22, wherein means for communicating with
the at least the second UE based on the one or more protocol layers
being configured for the broadcast operation is configured to
transmit, to the at least the second UE, a message including the
MAC CE indicating that the first UE will send a transmission.
24. The apparatus of claim 13, further comprising: means for
monitoring one or more radio resources for an announcement from the
at least the second UE, the at least the second UE belonging to a
D2D communication group of interest.
25. A apparatus of wireless communication for a first user
equipment (UE), comprising: a memory; and at least one processor
coupled to the memory and configured to: determine that an
application associated with public safety is initiated; configure a
radio resource control (RRC) protocol layer for device-to-device
(D2D) broadcast communication based on initiation of the
application associated with public safety; configure one or more
protocol layers for broadcast operation based on configuring the
RRC protocol layer for the D2D broadcast communication, the one or
more protocol layers being lower than the RRC protocol layer; and
communicate with at least a second UE based on the one or more
protocol layers being configured for the broadcast operation.
26. The apparatus of claim 25, wherein the at least one processor
is further configured to: configure a non-access stratum (NAS)
protocol layer based on the initiation of the application
associated with public safety, wherein the RRC protocol layer is
configured for the D2D broadcast communication based on the NAS
protocol layer being configured.
27. The apparatus of claim 26, wherein the configuration of the NAS
protocol layer comprises to set at least an Internet Protocol (IP)
address for the first UE, a priority for the first UE when the
first UE belongs to a D2D communication group, or an IP multicast
address when the first UE belongs to the D2D communication
group.
28. The apparatus of claim 25, wherein the at least one processor
is further configured to: configure at least a bearer for the D2D
broadcast communication.
29. The apparatus of claim 25, wherein the one or more protocol
layers lower than the RRC protocol layer comprises at least one of
a packet data convergence protocol (PDCP) layer, an radio link
control (RLC) layer, a medium access control (MAC) layer, or a
physical layer.
30. The apparatus of claim 29, wherein the configuration of the one
or more protocol layers for the broadcast operation based on the
configuration of the RRC protocol layer for the D2D broadcast
communication comprises to configure at least one of the PDCP layer
or the RLC layer to operate in a unidirectional mode (U-Mode).
31. The apparatus of claim 29, wherein the configuration of the one
or more protocol layers for the broadcast operation based on the
configuration of the RRC protocol layer for the D2D broadcast
communication comprises to: configure the MAC layer to generate a
MAC subheader, the MAC subheader comprising at least a session
identification (ID), a group ID that indicates a D2D communication
group to which the first UE belongs, or a source ID that indicates
an ID associated with the first UE.
32. The apparatus of claim 31, wherein the MAC subheader further
comprises duplicate packet identification information.
33. The apparatus of claim 31, wherein the MAC subheader further
comprises at least one of a priority of a session or a time
interval for which a lower priority session should not start.
34. The apparatus of claim 25, wherein the configuration of the one
or more protocol layers for the broadcast operation based on the
configuration of the RRC protocol layer for the D2D broadcast
communication comprises to: configure a medium access control (MAC)
layer to generate a MAC control element (CE) comprising at least a
group identification (ID) that indicates a D2D communication group
to which the first UE belongs, a source ID that indicates an ID
associated with the first UE, a priority of a session, or a time
interval for which a lower priority session should not start.
35. The apparatus of claim 34, wherein the communication with the
at least the second UE based on the one or more protocol layers
being configured for the broadcast operation comprises to:
transmit, to the at least the second UE, a message including the
MAC CE indicating that the first UE will send a transmission.
36. The apparatus of claim 25, wherein the at least one processor
is further configured to: monitor one or more radio resources for
an announcement from the at least the second UE, the at least the
second UE belonging to a D2D communication group of interest.
37. A computer-readable medium storing computer-executable code for
wireless communication by a first user equipment (UE), the code
when executed by a processor cause the processor to: determine that
an application associated with public safety is initiated;
configure a radio resource control (RRC) protocol layer for
device-to-device (D2D) broadcast communication based on initiation
of the application associated with public safety; configure one or
more protocol layers for broadcast operation based on configuring
the RRC protocol layer for the D2D broadcast communication, the one
or more protocol layers being lower than the RRC protocol layer;
and communicate with at least a second UE based on the one or more
protocol layers being configured for the broadcast operation.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 16/144,773, entitled "MAC SUBHEADER FOR D2D BROADCAST
COMMUNICATION FOR PUBLIC SAFETY" and filed on Sep. 27, 2018, which
is a continuation of U.S. application Ser. No. 14/483,962, entitled
"MAC SUBHEADER FOR D2D BROADCAST COMMUNICATION FOR PUBLIC SAFETY"
and filed on Sep. 11, 2014, now U.S. Pat. No. 10,117,224 issued on
Oct. 30, 2018, which claims the benefit of U.S. Provisional
Application Ser. No. 61/880,792, entitled "MAC SUBHEADER FOR D2D
BROADCAST COMMUNICATION FOR PUBLIC SAFETY" and filed on Sep. 20,
2013, the disclosures of which are expressly incorporated by
reference herein in their entireties.
BACKGROUND
Field
[0002] The present disclosure relates generally to communication
systems, and more particularly, to a MAC subheader for D2D
broadcast communication for public safety.
Background
[0003] Wireless communication systems are widely deployed to
provide various telecommunication services such as telephony,
video, data, messaging, and broadcasts. Typical wireless
communication systems may employ multiple-access technologies
capable of supporting communication with multiple users by sharing
available system resources (e.g., bandwidth, transmit power).
Examples of such multiple-access technologies include code division
multiple access (CDMA) systems, time division multiple access
(TDMA) systems, frequency division multiple access (FDMA) systems,
orthogonal frequency division multiple access (OFDMA) systems,
single-carrier frequency division multiple access (SC-FDMA)
systems, and time division synchronous code division multiple
access (TD-SCDMA) systems.
[0004] These multiple access technologies have been adopted in
various telecommunication standards to provide a common protocol
that enables different wireless devices to communicate on a
municipal, national, regional, and even global level. An example of
an emerging telecommunication standard is Long Term Evolution
(LTE). LTE is a set of enhancements to the Universal Mobile
Telecommunications System (UMTS) mobile standard promulgated by
Third Generation Partnership Project (3GPP). It is designed to
better support mobile broadband Internet access by improving
spectral efficiency, lowering costs, improving services, making use
of new spectrum, and better integrating with other open standards
using OFDMA on the downlink (DL), SC-FDMA on the uplink (UL), and
multiple-input multiple-output (MIMO) antenna technology. However,
as the demand for mobile broadband access continues to increase,
there exists a need for further improvements in LTE technology.
Preferably, these improvements should be applicable to other
multi-access technologies and the telecommunication standards that
employ these technologies.
SUMMARY
[0005] In an aspect of the disclosure, a method, a computer program
product, and an apparatus are provided. The apparatus configures at
least a non-access stratum (NAS) protocol layer or a radio resource
control (RRC) protocol layer to enable device-to-device (D2D)
communication with at least a second apparatus when the apparatus
is out of network coverage, and communicates with at least the
second apparatus.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a diagram illustrating an example of a network
architecture.
[0007] FIG. 2 is a diagram illustrating an example of an access
network.
[0008] FIG. 3 is a diagram illustrating an example of a DL frame
structure in LTE.
[0009] FIG. 4 is a diagram illustrating an example of an UL frame
structure in LTE.
[0010] FIG. 5 is a diagram illustrating an example of a radio
protocol architecture for the user and control planes.
[0011] FIG. 6 is a diagram illustrating an example of an evolved
Node B and user equipment in an access network.
[0012] FIG. 7 is a diagram of a device-to-device communications
system.
[0013] FIG. 8 is a diagram illustrating a protocol architecture for
D2D broadcast communication for public safety.
[0014] FIG. 9 is a diagram illustrating a format of a MAC subheader
for D2D broadcast communication.
[0015] FIG. 10 is a diagram illustrating a format of a MAC
subheader for D2D broadcast communication.
[0016] FIG. 11 is a diagram illustrating a format of a MAC
subheader for D2D broadcast communication.
[0017] FIG. 12 is a diagram illustrating a format of a MAC
subheader for D2D broadcast communication.
[0018] FIG. 13 is a diagram illustrating a format of a MAC
subheader for D2D broadcast communication.
[0019] FIG. 14 is a diagram illustrating a high level procedure of
direct one-to-many broadcast communication for public safety.
[0020] FIG. 15 is a diagram illustrating a MAC subheader for a new
MAC control element (CE) used in D2D broadcast communication.
[0021] FIG. 16 is a diagram illustrating a format of a new MAC CE
for group session announcement in D2D broadcast communication.
[0022] FIG. 17 is a diagram illustrating a format of a new MAC CE
for group session announcement in D2D broadcast communication.
[0023] FIG. 18 is a diagram illustrating a format of a new MAC CE
for group session announcement in D2D broadcast communication.
[0024] FIG. 19 is a flow chart of a method of wireless
communication.
[0025] FIG. 20 is a conceptual data flow diagram illustrating the
data flow between different modules/means/components in an
exemplary apparatus.
[0026] FIG. 21 is a diagram illustrating an example of a hardware
implementation for an apparatus employing a processing system.
DETAILED DESCRIPTION
[0027] The detailed description set forth below in connection with
the appended drawings is intended as a description of various
configurations and is not intended to represent the only
configurations in which the concepts described herein may be
practiced. The detailed description includes specific details for
the purpose of providing a thorough understanding of various
concepts. However, it will be apparent to those skilled in the art
that these concepts may be practiced without these specific
details. In some instances, well known structures and components
are shown in block diagram form in order to avoid obscuring such
concepts.
[0028] Several aspects of telecommunication systems will now be
presented with reference to various apparatus and methods. These
apparatus and methods will be described in the following detailed
description and illustrated in the accompanying drawings by various
blocks, modules, components, circuits, steps, processes,
algorithms, etc. (collectively referred to as "elements"). These
elements may be implemented using electronic hardware, computer
software, or any combination thereof. Whether such elements are
implemented as hardware or software depends upon the particular
application and design constraints imposed on the overall
system.
[0029] By way of example, an element, or any portion of an element,
or any combination of elements may be implemented with a
"processing system" that includes one or more processors. Examples
of processors include microprocessors, microcontrollers, digital
signal processors (DSPs), field programmable gate arrays (FPGAs),
programmable logic devices (PLDs), state machines, gated logic,
discrete hardware circuits, and other suitable hardware configured
to perform the various functionality described throughout this
disclosure. One or more processors in the processing system may
execute software. Software shall be construed broadly to mean
instructions, instruction sets, code, code segments, program code,
programs, subprograms, software modules, applications, software
applications, software packages, routines, subroutines, objects,
executables, threads of execution, procedures, functions, etc.,
whether referred to as software, firmware, middleware, microcode,
hardware description language, or otherwise.
[0030] Accordingly, in one or more exemplary embodiments, the
functions described may be implemented in hardware, software,
firmware, or any combination thereof. If implemented in software,
the functions may be stored on or encoded as one or more
instructions or code on a computer-readable medium.
Computer-readable media includes computer storage media. Storage
media may be any available media that can be accessed by a
computer. By way of example, and not limitation, such
computer-readable media can comprise a random-access memory (RAM),
a read-only memory (ROM), an electrically erasable programmable ROM
(EEPROM), compact disk ROM (CD-ROM) or other optical disk storage,
magnetic disk storage or other magnetic storage devices, or any
other medium that can be used to carry or store desired program
code in the form of instructions or data structures and that can be
accessed by a computer. Disk and disc, as used herein, includes CD,
laser disc, optical disc, digital versatile disc (DVD), and floppy
disk where disks usually reproduce data magnetically, while discs
reproduce data optically with lasers. Combinations of the above
should also be included within the scope of computer-readable
media.
[0031] FIG. 1 is a diagram illustrating an LTE network architecture
100. The LTE network architecture 100 may be referred to as an
Evolved Packet System (EPS) 100. The EPS 100 may include one or
more user equipment (UE) 102, an Evolved UMTS Terrestrial Radio
Access Network (E-UTRAN) 104, an Evolved Packet Core (EPC) 110, a
Home Subscriber Server (HSS) 120, and an Operator's Internet
Protocol (IP) Services 122. The EPS can interconnect with other
access networks, but for simplicity those entities/interfaces are
not shown. As shown, the EPS provides packet-switched services,
however, as those skilled in the art will readily appreciate, the
various concepts presented throughout this disclosure may be
extended to networks providing circuit-switched services.
[0032] The E-UTRAN includes the evolved Node B (eNB) 106 and other
eNBs 108. The eNB 106 provides user and control planes protocol
terminations toward the UE 102. The eNB 106 may be connected to the
other eNBs 108 via a backhaul (e.g., an X2 interface). The eNB 106
may also be referred to as a base station, a Node B, an access
point, a base transceiver station, a radio base station, a radio
transceiver, a transceiver function, a basic service set (BSS), an
extended service set (ESS), or some other suitable terminology. The
eNB 106 provides an access point to the EPC 110 for a UE 102.
Examples of UEs 102 include a cellular phone, a smart phone, a
session initiation protocol (SIP) phone, a laptop, a personal
digital assistant (PDA), a satellite radio, a global positioning
system, a multimedia device, a video device, a digital audio player
(e.g., MP3 player), a camera, a game console, a tablet, or any
other similar functioning device. The UE 102 may also be referred
to by those skilled in the art as a mobile station, a subscriber
station, a mobile unit, a subscriber unit, a wireless unit, a
remote unit, a mobile device, a wireless device, a wireless
communications device, a remote device, a mobile subscriber
station, an access terminal, a mobile terminal, a wireless
terminal, a remote terminal, a handset, a user agent, a mobile
client, a client, or some other suitable terminology.
[0033] The eNB 106 is connected to the EPC 110. The EPC 110 may
include a Mobility Management Entity (MME) 112, other MMES 114, a
Serving Gateway 116, a Multimedia Broadcast Multicast Service
(MBMS) Gateway 124, a Broadcast Multicast Service Center (BM-SC)
126, and a Packet Data Network (PDN) Gateway 118. The MME 112 is
the control node that processes the signaling between the UE 102
and the EPC 110. Generally, the MME 112 provides bearer and
connection management. All user IP packets are transferred through
the Serving Gateway 116, which itself is connected to the PDN
Gateway 118. The PDN Gateway 118 provides UE IP address allocation
as well as other functions. The PDN Gateway 118 is connected to the
Operator's IP Services 122. The Operator's IP Services 122 may
include the Internet, an intranet, an IP Multimedia Subsystem
(IMS), and a PS Streaming Service (PSS). The BM-SC 126 may provide
functions for MBMS user service provisioning and delivery. The
BM-SC 126 may serve as an entry point for content provider MBMS
transmission, may be used to authorize and initiate MBMS Bearer
Services within a PLMN, and may be used to schedule and deliver
MBMS transmissions. The MBMS Gateway 124 may be used to distribute
MBMS traffic to the eNBs (e.g., 106, 108) belonging to a Multicast
Broadcast Single Frequency Network (MBSFN) area broadcasting a
particular service, and may be responsible for session management
(start/stop) and for collecting eMBMS related charging
information.
[0034] FIG. 2 is a diagram illustrating an example of an access
network 200 in an LTE network architecture. In this example, the
access network 200 is divided into a number of cellular regions
(cells) 202. One or more lower power class eNBs 208 may have
cellular regions 210 that overlap with one or more of the cells
202. The lower power class eNB 208 may be a femto cell (e.g., home
eNB (HeNB)), pico cell, micro cell, or remote radio head (RRH). The
macro eNBs 204 are each assigned to a respective cell 202 and are
configured to provide an access point to the EPC 110 for all the
UEs 206 in the cells 202. There is no centralized controller in
this example of an access network 200, but a centralized controller
may be used in alternative configurations. The eNBs 204 are
responsible for all radio related functions including radio bearer
control, admission control, mobility control, scheduling, security,
and connectivity to the serving gateway 116. An eNB may support one
or multiple (e.g., three) cells (also referred to as a sector). The
term "cell" can refer to the smallest coverage area of an eNB
and/or an eNB subsystem serving are particular coverage area.
Further, the terms "eNB," "base station," and "cell" may be used
interchangeably herein.
[0035] The modulation and multiple access scheme employed by the
access network 200 may vary depending on the particular
telecommunications standard being deployed. In LTE applications,
OFDM is used on the DL and SC-FDMA is used on the UL to support
both frequency division duplex (FDD) and time division duplex
(TDD). As those skilled in the art will readily appreciate from the
detailed description to follow, the various concepts presented
herein are well suited for LTE applications. However, these
concepts may be readily extended to other telecommunication
standards employing other modulation and multiple access
techniques. By way of example, these concepts may be extended to
Evolution-Data Optimized (EV-DO) or Ultra Mobile Broadband (UMB).
EV-DO and UMB are air interface standards promulgated by the 3rd
Generation Partnership Project 2 (3GPP2) as part of the CDMA2000
family of standards and employs CDMA to provide broadband Internet
access to mobile stations. These concepts may also be extended to
Universal Terrestrial Radio Access (UTRA) employing Wideband-CDMA
(W-CDMA) and other variants of CDMA, such as TD-SCDMA; Global
System for Mobile Communications (GSM) employing TDMA; and Evolved
UTRA (E-UTRA), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE
802.20, and Flash-OFDM employing OFDMA. UTRA, E-UTRA, UMTS, LTE and
GSM are described in documents from the 3GPP organization. CDMA2000
and UMB are described in documents from the 3GPP2 organization. The
actual wireless communication standard and the multiple access
technology employed will depend on the specific application and the
overall design constraints imposed on the system.
[0036] The eNBs 204 may have multiple antennas supporting MIMO
technology. The use of MIMO technology enables the eNBs 204 to
exploit the spatial domain to support spatial multiplexing,
beamforming, and transmit diversity. Spatial multiplexing may be
used to transmit different streams of data simultaneously on the
same frequency. The data streams may be transmitted to a single UE
206 to increase the data rate or to multiple UEs 206 to increase
the overall system capacity. This is achieved by spatially
precoding each data stream (i.e., applying a scaling of an
amplitude and a phase) and then transmitting each spatially
precoded stream through multiple transmit antennas on the DL. The
spatially precoded data streams arrive at the UE(s) 206 with
different spatial signatures, which enables each of the UE(s) 206
to recover the one or more data streams destined for that UE 206.
On the UL, each UE 206 transmits a spatially precoded data stream,
which enables the eNB 204 to identify the source of each spatially
precoded data stream.
[0037] Spatial multiplexing is generally used when channel
conditions are good. When channel conditions are less favorable,
beamforming may be used to focus the transmission energy in one or
more directions. This may be achieved by spatially precoding the
data for transmission through multiple antennas. To achieve good
coverage at the edges of the cell, a single stream beamforming
transmission may be used in combination with transmit
diversity.
[0038] In the detailed description that follows, various aspects of
an access network will be described with reference to a MIMO system
supporting OFDM on the DL. OFDM is a spread-spectrum technique that
modulates data over a number of subcarriers within an OFDM symbol.
The subcarriers are spaced apart at precise frequencies. The
spacing provides "orthogonality" that enables a receiver to recover
the data from the subcarriers. In the time domain, a guard interval
(e.g., cyclic prefix) may be added to each OFDM symbol to combat
inter-OFDM-symbol interference. The UL may use SC-FDMA in the form
of a DFT-spread OFDM signal to compensate for high peak-to-average
power ratio (PAPR).
[0039] FIG. 3 is a diagram 300 illustrating an example of a DL
frame structure in LTE. A frame (10 ms) may be divided into 10
equally sized subframes. Each subframe may include two consecutive
time slots. A resource grid may be used to represent two time
slots, each time slot including a resource block. The resource grid
is divided into multiple resource elements. In LTE, a resource
block contains 12 consecutive subcarriers in the frequency domain
and, for a normal cyclic prefix in each OFDM symbol, 7 consecutive
OFDM symbols in the time domain, or 84 resource elements. For an
extended cyclic prefix, a resource block contains 6 consecutive
OFDM symbols in the time domain and has 72 resource elements. Some
of the resource elements, indicated as R 302, 304, include DL
reference signals (DL-RS). The DL-RS include Cell-specific RS (CRS)
(also sometimes called common RS) 302 and UE-specific RS (UE-RS)
304. UE-RS 304 are transmitted only on the resource blocks upon
which the corresponding physical DL shared channel (PDSCH) is
mapped. The number of bits carried by each resource element depends
on the modulation scheme. Thus, the more resource blocks that a UE
receives and the higher the modulation scheme, the higher the data
rate for the UE.
[0040] FIG. 4 is a diagram 400 illustrating an example of an UL
frame structure in LTE. The available resource blocks for the UL
may be partitioned into a data section and a control section. The
control section may be formed at the two edges of the system
bandwidth and may have a configurable size. The resource blocks in
the control section may be assigned to UEs for transmission of
control information. The data section may include all resource
blocks not included in the control section. The UL frame structure
results in the data section including contiguous subcarriers, which
may allow a single UE to be assigned all of the contiguous
subcarriers in the data section.
[0041] A UE may be assigned resource blocks 410a, 410b in the
control section to transmit control information to an eNB. The UE
may also be assigned resource blocks 420a, 420b in the data section
to transmit data to the eNB. The UE may transmit control
information in a physical UL control channel (PUCCH) on the
assigned resource blocks in the control section. The UE may
transmit only data or both data and control information in a
physical UL shared channel (PUSCH) on the assigned resource blocks
in the data section. A UL transmission may span both slots of a
subframe and may hop across frequency.
[0042] A set of resource blocks may be used to perform initial
system access and achieve UL synchronization in a physical random
access channel (PRACH) 430. The PRACH 430 carries a random sequence
and cannot carry any UL data/signaling. Each random access preamble
occupies a bandwidth corresponding to six consecutive resource
blocks. The starting frequency is specified by the network. That
is, the transmission of the random access preamble is restricted to
certain time and frequency resources. There is no frequency hopping
for the PRACH. The PRACH attempt is carried in a single subframe (1
ms) or in a sequence of few contiguous subframes and a UE can make
only a single PRACH attempt per frame (10 ms).
[0043] FIG. 5 is a diagram 500 illustrating an example of a radio
protocol architecture for the user and control planes in LTE. The
radio protocol architecture for the UE and the eNB is shown with
three layers: Layer 1, Layer 2, and Layer 3. Layer 1 (L1 layer) is
the lowest layer and implements various physical layer signal
processing functions. The L1 layer will be referred to herein as
the physical layer 506. Layer 2 (L2 layer) 508 is above the
physical layer 506 and is responsible for the link between the UE
and eNB over the physical layer 506.
[0044] In the user plane, the L2 layer 508 includes a media access
control (MAC) sublayer 510, a radio link control (RLC) sublayer
512, and a packet data convergence protocol (PDCP) 514 sublayer,
which are terminated at the eNB on the network side. Although not
shown, the UE may have several upper layers above the L2 layer 508
including a network layer (e.g., IP layer) that is terminated at
the PDN gateway 118 on the network side, and an application layer
that is terminated at the other end of the connection (e.g., far
end UE, server, etc.).
[0045] The PDCP sublayer 514 provides multiplexing between
different radio bearers and logical channels. The PDCP sublayer 514
also provides header compression for upper layer data packets to
reduce radio transmission overhead, security by ciphering the data
packets, and handover support for UEs between eNBs. The RLC
sublayer 512 provides segmentation and reassembly of upper layer
data packets, retransmission of lost data packets, and reordering
of data packets to compensate for out-of-order reception due to
hybrid automatic repeat request (HARQ). The MAC sublayer 510
provides multiplexing between logical and transport channels. The
MAC sublayer 510 is also responsible for allocating the various
radio resources (e.g., resource blocks) in one cell among the UEs.
The MAC sublayer 510 is also responsible for HARQ operations.
[0046] In the control plane, the radio protocol architecture for
the UE and eNB is substantially the same for the physical layer 506
and the L2 layer 508 with the exception that there is no header
compression function for the control plane. The control plane also
includes a radio resource control (RRC) sublayer 516 in Layer 3 (L3
layer). The RRC sublayer 516 is responsible for obtaining radio
resources (e.g., radio bearers) and for configuring the lower
layers using RRC signaling between the eNB and the UE.
[0047] FIG. 6 is a block diagram of an eNB 610 in communication
with a UE 650 in an access network. In the DL, upper layer packets
from the core network are provided to a controller/processor 675.
The controller/processor 675 implements the functionality of the L2
layer. In the DL, the controller/processor 675 provides header
compression, ciphering, packet segmentation and reordering,
multiplexing between logical and transport channels, and radio
resource allocations to the UE 650 based on various priority
metrics. The controller/processor 675 is also responsible for HARQ
operations, retransmission of lost packets, and signaling to the UE
650.
[0048] The transmit (TX) processor 616 implements various signal
processing functions for the L1 layer (i.e., physical layer). The
signal processing functions include coding and interleaving to
facilitate forward error correction (FEC) at the UE 650 and mapping
to signal constellations based on various modulation schemes (e.g.,
binary phase-shift keying (BPSK), quadrature phase-shift keying
(QPSK), M-phase-shift keying (M-PSK), M-quadrature amplitude
modulation (M-QAM)). The coded and modulated symbols are then split
into parallel streams. Each stream is then mapped to an OFDM
subcarrier, multiplexed with a reference signal (e.g., pilot) in
the time and/or frequency domain, and then combined together using
an Inverse Fast Fourier Transform (IFFT) to produce a physical
channel carrying a time domain OFDM symbol stream. The OFDM stream
is spatially precoded to produce multiple spatial streams. Channel
estimates from a channel estimator 674 may be used to determine the
coding and modulation scheme, as well as for spatial processing.
The channel estimate may be derived from a reference signal and/or
channel condition feedback transmitted by the UE 650. Each spatial
stream may then be provided to a different antenna 620 via a
separate transmitter 618TX. Each transmitter 618TX may modulate an
RF carrier with a respective spatial stream for transmission.
[0049] At the UE 650, each receiver 654RX receives a signal through
its respective antenna 652. Each receiver 654RX recovers
information modulated onto an RF carrier and provides the
information to the receive (RX) processor 656. The RX processor 656
implements various signal processing functions of the L1 layer. The
RX processor 656 may perform spatial processing on the information
to recover any spatial streams destined for the UE 650. If multiple
spatial streams are destined for the UE 650, they may be combined
by the RX processor 656 into a single OFDM symbol stream. The RX
processor 656 then converts the OFDM symbol stream from the
time-domain to the frequency domain using a Fast Fourier Transform
(FFT). The frequency domain signal comprises a separate OFDM symbol
stream for each subcarrier of the OFDM signal. The symbols on each
subcarrier, and the reference signal, are recovered and demodulated
by determining the most likely signal constellation points
transmitted by the eNB 610. These soft decisions may be based on
channel estimates computed by the channel estimator 658. The soft
decisions are then decoded and deinterleaved to recover the data
and control signals that were originally transmitted by the eNB 610
on the physical channel. The data and control signals are then
provided to the controller/processor 659.
[0050] The controller/processor 659 implements the L2 layer. The
controller/processor can be associated with a memory 660 that
stores program codes and data. The memory 660 may be referred to as
a computer-readable medium. In the UL, the controller/processor 659
provides demultiplexing between transport and logical channels,
packet reassembly, deciphering, header decompression, control
signal processing to recover upper layer packets from the core
network. The upper layer packets are then provided to a data sink
662, which represents all the protocol layers above the L2 layer.
Various control signals may also be provided to the data sink 662
for L3 processing. The controller/processor 659 is also responsible
for error detection using an acknowledgement (ACK) and/or negative
acknowledgement (NACK) protocol to support HARQ operations.
[0051] In the UL, a data source 667 is used to provide upper layer
packets to the controller/processor 659. The data source 667
represents all protocol layers above the L2 layer. Similar to the
functionality described in connection with the DL transmission by
the eNB 610, the controller/processor 659 implements the L2 layer
for the user plane and the control plane by providing header
compression, ciphering, packet segmentation and reordering, and
multiplexing between logical and transport channels based on radio
resource allocations by the eNB 610. The controller/processor 659
is also responsible for HARQ operations, retransmission of lost
packets, and signaling to the eNB 610.
[0052] Channel estimates derived by a channel estimator 658 from a
reference signal or feedback transmitted by the eNB 610 may be used
by the TX processor 668 to select the appropriate coding and
modulation schemes, and to facilitate spatial processing. The
spatial streams generated by the TX processor 668 may be provided
to different antenna 652 via separate transmitters 654TX. Each
transmitter 654TX may modulate an RF carrier with a respective
spatial stream for transmission.
[0053] The UL transmission is processed at the eNB 610 in a manner
similar to that described in connection with the receiver function
at the UE 650. Each receiver 618RX receives a signal through its
respective antenna 620. Each receiver 618RX recovers information
modulated onto an RF carrier and provides the information to a RX
processor 670. The RX processor 670 may implement the L1 layer.
[0054] The controller/processor 675 implements the L2 layer. The
controller/processor 675 can be associated with a memory 676 that
stores program codes and data. The memory 676 may be referred to as
a computer-readable medium. In the UL, the control/processor 675
provides demultiplexing between transport and logical channels,
packet reassembly, deciphering, header decompression, control
signal processing to recover upper layer packets from the UE 650.
Upper layer packets from the controller/processor 675 may be
provided to the core network. The controller/processor 675 is also
responsible for error detection using an ACK and/or NACK protocol
to support HARQ operations.
[0055] FIG. 7 is a diagram of a device-to-device (D2D)
communications system 700. The D2D communications system 700
includes a plurality of wireless devices (also referred to as UEs)
704, 706, 708, 710. The D2D communications system 700 may overlap
with a cellular communications system, such as for example, a
wireless wide area network (WWAN). Some of the wireless devices
704, 706, 708, 710 may communicate together in D2D communication
using the DL/UL WWAN spectrum, some may communicate with the base
station 702, and some may do both. For example, as shown in FIG. 7,
the wireless devices 708, 710 are in D2D communication and the
wireless devices 704, 706 are in D2D communication. The wireless
devices 704, 706 are also communicating with the base station 702.
In the configuration of FIG. 7, the wireless devices 708 and 710
are out of network coverage and, therefore, may not receive
assistance from base station 702. As described herein, the term
"out of network coverage" may refer to a situation where the
wireless devices 708 and 710 are out of the communication range of
the base station 702 or a situation where the base station 702 is
not functional.
[0056] The exemplary methods and apparatuses discussed infra are
applicable to any of a variety of wireless device-to-device
communications systems, such as for example, a wireless
device-to-device communication system based on FlashLinQ, WiMedia,
Bluetooth, ZigBee, or Wi-Fi based on the IEEE 802.11 standard. To
simplify the discussion, the exemplary methods and apparatus are
discussed within the context of LTE. However, one of ordinary skill
in the art would understand that the exemplary methods and
apparatuses are applicable more generally to a variety of other
wireless D2D communication systems.
[0057] D2D one-to-many broadcast communication is the mechanism for
communication between UEs of a group for public safety. As
discussed infra, D2D broadcast communication can be achieved by
reusing at least a portion of the LTE protocol stack.
[0058] FIG. 8 is a diagram illustrating a protocol architecture 800
of a first UE for D2D broadcast communication for public safety. As
shown in FIG. 8, the protocol architecture 800 includes a public
safety application 802, a non-access stratum (NAS) protocol layer
(also referred to as "NAS") 804, an RRC protocol layer 806, a user
datagram protocol (UDP)/IP layer 808, a PDCP layer 810, an RLC
layer 812, a MAC layer 814, and a physical layer (L1) 816.
[0059] In an aspect, when an application (e.g., public safety
application 802) is activated by a user of a UE (e.g., UE 708), the
public safety application 802 may send an indication to the NAS
804. For example, the application may be a public safety
application used for communicating emergency messages by members of
a police department, fire department, or other public safety
personnel. In response to the indication, NAS 804 may configure
itself and may optionally configure RRC 806. In an aspect, the
configuration performed by NAS 804 may involve setting an
individual IP address for the UE, a priority for the groups
handling, and an IP multicast address for the groups where the UE
has the group membership. The NAS 804 may also configure a bearer
specific to D2D broadcast communication and associated traffic flow
templates (TFTs).
[0060] In an aspect, the RRC 806 can autonomously transition to a
D2D communication state to allow for D2D communication with one or
more UEs (e.g., UE 710) when the UE 708 is out of network coverage.
In an aspect, such autonomous transition can be achieved by an
indication (e.g., a broadcast public safety communication
indication) received by the RRC 806 from either the public safety
application 802 running on the UE 708 or from NAS 804 when NAS 804
receives this indication from the public safety application 802.
For example, whenever the public safety application 802 is
initiated by the user of the UE 708, the previously described
indication may be provided to the RRC 806. In response to the
indication, the RRC 806 may transition to a new state (e.g., a
"D2D-Idle" state or a "D2D-Connected" state, which may also
collectively be referred to as a "D2D communication state") with
respect to the presently available RRC states (e.g., "RRC Idle" or
"RRC Connected"). The new state of the RRC 806 is specific for D2D
broadcast communication operation. When the RRC 806 transitions to
this new state, such transition does not affect WAN RRC state.
[0061] The transition from the D2D-Idle state to the D2D-Connected
state can take place in following manner. In an aspect, when the
public safety application 802 is activated in the UE 708, the RRC
806 enters the D2D-Idle state. If the UE 708 has something to
transmit, the UE 708 enters the D2D-Connected state and transmits
an identity of the group (e.g., a group ID) to which the UE 708
belongs and/or an identity of the transmitter (e.g., a source ID
associated with the UE 708) on one particular channel to which all
other D2D-Idle UEs are listening. Alternatively, the UE 708
transmits the group ID and/or source ID in a specified time slot
which all other D2D-Idle UEs are listening.
[0062] In an aspect, UEs belonging to the same group enter the
D2D-Connected state and start to monitor the complete band. After
transmitting a group activation (or group session announcement) for
some predefined times, the UE 708 may begin transmission.
Accordingly, since UEs of a particular group enter the
D2D-Connected state at times when transmissions will occur, the
previously described aspect may reduce power consumption in the UEs
during D2D communications.
[0063] In an aspect, when a public safety application is activated,
the UE 708 may enter the D2D-Connected state. In such aspect, all
the UEs in the group may enter and remain in the D2D-Connected
state all the time (as soon as the public safety application 802 is
activated). In an aspect, a group session announcement may be
transmitted by the UE 708 to prevent all UEs from entering and
remaining in the D2D-Connected state all the time. For example,
once a session announcement is received by a UE, the UE may start
to monitor each subframe (assigned for D2D communication) for the
duration of a preconfigured in-activity timer. This in-activity
timer is reset every time a packet is sent/received before entering
the D2D-Idle state. A session ID can also be part of group session
announcement and there can be one in-activity timer per session ID.
The session ID can be part of each MAC subheader and session
announcement MAC CE as explained infra.
[0064] When the RRC 806 transitions to the new state specific for
D2D broadcast communication in response to an indication from the
public safety application 802, the RRC 806 may configure other
protocol layers, such as the PDCP layer 810, the RLC layer 812, the
MAC layer 814, and/or the physical layer 816 for D2D broadcast
operation. The RRC 806 can have this information pre-configured so
that the RRC 806 can work in an out of network coverage scenario as
well.
[0065] In an aspect, since there is no peer to peer connection,
public safety broadcast communication can be considered as a
connectionless approach. Therefore, there may be no need for
connection management.
[0066] Header compression can help reduce the header size in D2D
transmissions. However, since feedback from PDCP is not available
when the UE 708 is out of network coverage, header compression
without feedback may be needed. PDCP may perform robust header
compression (ROHC), which supports three modes. One such mode,
known as unidirectional mode (or U-Mode), can be used for header
compression without feedback. In the U-Mode, the transmitter (e.g.,
UE 708) periodically sends a full header to enable the decompressor
to avoid errors. The other two modes supported by ROHC are
bidirectional and require feedback. Therefore, in an aspect, the
other two modes may not be used for public safety broadcast
communication.
[0067] As previously discussed, feedback may not be needed for
public safety broadcast communication so RLC U-Mode can be used for
user data without any change. In an aspect, there may be no need to
transfer any control plane messages and, therefore, TM mode may not
be needed.
[0068] FIG. 9 is a diagram illustrating a format of a MAC subheader
900 for D2D broadcast communication. As shown in FIG. 9, the MAC
subheader 900 includes reserved header fields 902 and 904,
extension header field 906, logical channel ID (LCID) field 908,
group ID field 910, source ID field 912, format field 914, and
length field 916.
[0069] A MAC (e.g., MAC layer 814) may perform a multiplexing
function with respect to broadcast communication. To achieve such
function, a new logical channel may be defined for D2D broadcast
communication (e.g., D-BCCH). D-BCCH maps to the transport channel
defined by RAN1 for broadcast communication for public safety. The
broadcast of one group may need to be distinguished from another
group so that a UE (e.g., UE 708) forwards only relevant packets
(e.g., packets belonging to the groups of interest to a UE) to
upper layers for further processing. This can be achieved by
embedding a group ID into each packet transmitted by any
transmitter of the group. For example, a Direct Group ID (DGI) can
be pre-configured by higher layers and provided to MAC layer 814 at
the time of configuration of MAC layer 814 when RRC 806 is
activated for D2D broadcast communication.
[0070] In an aspect, the group ID field 910 and the source ID field
912 may each be 8 bits in size. The source ID field 912 may include
a source ID (e.g., an 8 bit value) or transmitter ID indicating the
identity of the transmitter in the group. The source ID may be
pre-configured in the UE (e.g., UE 708) in a manner similar to the
group ID. The MAC subheader 900 may be used each time a MAC SDU is
to be broadcasted by the UE 708 for D2D communication.
[0071] FIG. 10 is a diagram illustrating a format of a MAC
subheader 1000 for D2D broadcast communication. As shown in FIG.
10, the MAC subheader 1000 includes reserved header fields 1002 and
1004, extension header field 1006, LCID field 1008, session ID
field 1010, group ID field 1012, source ID field 1014, format field
1016, and length field 1018. In the configuration of FIG. 10, the
session ID field 1010 may identify a particular session to allow
UEs involved in D2D communication to distinguish sessions.
[0072] FIG. 11 is a diagram illustrating a format of a MAC
subheader 1100 for D2D broadcast communication. As shown in FIG.
11, the MAC subheader 1100 includes reserved header fields 1102 and
1104, extension header field 1106, LCID field 1108, session ID
field 1110, num group field 1112, group ID 1 field 1114, group ID n
field 1116, source ID field 1118, format field 1120, and length
field 1122.
[0073] In an aspect, one UE may be part of multiple groups. In such
aspect, the groups to which a UE belongs can be indicated using the
multiple group ID fields (e.g., group ID 1 to group ID n) included
in the MAC subheader 1100. In an aspect, the num group field 1112
indicates the number of group IDs present in the MAC subheader
1100.
[0074] FIG. 12 is a diagram illustrating a format of a MAC
subheader 1200 for D2D broadcast communication. As shown in FIG.
12, the MAC subheader 1200 includes reserved header fields 1202 and
1204, extension header field 1206, LCID field 1208, session ID
field 1210, num group field 1212, group ID 1 field 1214, source ID
1 field 1216, group ID n field 1218, source ID n field 1220, format
field 1222, and length field 1224.
[0075] In an aspect, one UE may be part of multiple groups and may
have a corresponding source ID for each of the groups. For example,
each source ID indicated in the source ID 1 field 1216 and the
source ID n field 1220 may be different. The number of group ID and
source ID pairs included in the MAC subheader 1200 may be indicated
in the num group field 1212.
[0076] FIG. 13 is a diagram illustrating a format of a MAC
subheader 1300 for D2D broadcast communication. As shown in FIG.
13, the MAC subheader 1300 includes reserved header fields 1302 and
1304, extension header field 1306, LCID field 1308, session ID
field 1310, SDU number field 1312, group ID field 1314, source ID
field 1316, format field 1318, and length field 1320.
[0077] D2D broadcast for public safety may not have physical layer
feedback (e.g., HARQ feedback), therefore physical layer packets
may be repeatedly transmitted multiple times in order to achieve
reliable communication. Accordingly, some UEs may receive the same
packets multiple times. Notwithstanding that the PDCP layer
provides duplicate packet detection, it may be efficient to discard
duplicate packets at the MAC layer so that processing at the PDCP
level related to header decompression may be avoided. Accordingly,
in an aspect, the SDU number field 1312 may carry information
including one or more bits and may wrap around so that duplicate
packets can be detected. In an aspect, if the SDU number field 1312
is configured to include only one bit, then the SDU field 1312
toggles between 0 and 1. It should be appreciated that the SDU
number field 1312 may be combined with other aspects discussed
herein to enable duplicate packet detection.
[0078] FIG. 14 is a diagram 1400 illustrating a high level
procedure of direct one-to-many broadcast communication for public
safety. As shown in FIG. 14, multiple UEs (e.g., UE-1 1402, UE-2
1404, UE-3 1406) are each preconfigured with group information
1408, 1410, 1412 and subsequently perform a group discovery
procedure 1414. Once the public safety application is activated in
a UE, the UE starts monitoring all the broadcast channels to see if
there is any packet from the group it is interested in. This always
monitoring mode can increase power consumption. Therefore, to
optimize the power consumption, a group session announcement 1416,
1418 can be used. For example, all the UEs periodically monitor
certain radio resources for the announcement of a member UE from
the group of interest. The announcement is an indication that the
UE is about to broadcast data so that all the UEs of the group
start monitoring all broadcasts continuously. A UE (e.g., UE-1
1402) that sends the group session announcement 1416 may access
radio resources 1420 to send a group communication and the other
UEs (e.g., UE-2 1404 and UE-3 1406) may prepare to listen to the
group communication 1422, 1424. The UE (e.g., UE-1 1402) may then
transmit to the other UEs (e.g., UE-2 1404 and UE-3 1406) 1426,
1428.
[0079] FIG. 15 is a diagram illustrating a MAC subheader 1500 for a
new MAC control element (CE) used in D2D broadcast communication.
As shown in FIG. 15, the MAC subheader 1500 includes reserved
header fields 1502 and 1504, extension header field 1506, and LCID
field 1508. In an aspect, the LCID field 1508 may include a new
LCID in the uplink defined for a new MAC CE as described infra. The
new MAC CE may be used for a group session announcement.
[0080] FIG. 16 is a diagram illustrating a format of a new MAC CE
1600 for group session announcement in D2D broadcast communication.
In an aspect, the MAC CE 1600 may include a group ID field 1602 and
a source ID field 1604.
[0081] FIG. 17 is a diagram illustrating a format of a new MAC CE
1700 for group session announcement in D2D broadcast communication.
In an aspect, the MAC CE 1700 may include a session ID field 1702,
group ID field 1704, and a source ID field 1706.
[0082] FIG. 18 is a diagram illustrating a format of a new MAC CE
1800 for group session announcement in D2D broadcast communication.
In an aspect, the MAC CE 1800 may include a group ID field 1802, a
source ID field 1804, a priority field 1806, and a time interval
(also referred to as "NA Time") field 1808. In an aspect, the
priority field 1806 may indicate a priority of the session and the
NA Time field 1808 may include a time interval for which a lower
priority session of a same or other group should not start.
[0083] In an aspect, the priority of a session may be
pre-configured in the UE. In another aspect, the priority may be
activated by user of the UE via the public safety application. For
example, when a user increases the priority of a session, other UEs
involved in lower priority group communications may yield (e.g.,
wait to transmit) to higher priority communications for a time
(e.g., NA Time) indicated in the MAC CE 1800. Such yielding may
result in power savings for the UEs involved in lower priority
group communications.
[0084] It should be appreciated that in other aspects, the MAC CEs
1600, 1700, and/or 1800 may include multiple group IDs, multiple
group ID and source ID pairs, and/or a field indicating the number
of group IDs or group ID/source ID pairs present in MAC CE.
[0085] FIG. 19 is a flow chart 1900 of a method of wireless
communication. The method may be performed by a UE (also referred
to as a first UE), such as UE 708 in FIG. 7. At step 1902, the UE
initiates an application for D2D communication. For example, the
application may be a public safety application used for
communicating emergency messages by members of a police or fire
department.
[0086] At step 1904, the UE configures a NAS protocol layer and/or
an RRC protocol layer to enable D2D communication with at least a
second UE (e.g., UE 710 in FIG. 7) when the first UE is out of
network coverage. In an aspect, the UE configures the NAS protocol
layer and/or the RRC protocol layer in response to the initiation
of the application. In an aspect, configuration of the NAS protocol
layer includes setting at least an IP address for the first UE, a
priority for the first UE when the first UE belongs to a D2D
communication group, or an IP multicast address when the first UE
belongs to the D2D communication group.
[0087] In an aspect, the NAS protocol layer configures at least a
bearer for the D2D communication or one or more traffic flow
templates (TFTs). In an aspect, configuration of the RRC protocol
layer includes transitioning the RRC protocol layer to a D2D
communication state (e.g., a D2D-Idle state or D2D-Connected
state). In an aspect, the RRC protocol layer in the D2D
communication state configures one or more protocol layers for the
D2D communication. For example, the one or more protocol layers may
include a PDCP layer, an RLC layer, a MAC layer, or a physical
layer (L1). In an aspect, the RRC protocol layer in the D2D
communication state configures at least the PDCP layer or the RLC
layer to operate in a U-Mode.
[0088] In an aspect, the RRC protocol layer in the D2D
communication state configures a MAC layer to generate a MAC
subheader, the MAC subheader comprising at least a session ID, a
group ID that indicates a D2D communication group to which the
first UE belongs, or a source ID that indicates an ID associated
with the first UE. In an aspect, the MAC subheader may include
group number information that indicates a number of group IDs
included in the MAC subheader. In an aspect, the MAC subheader may
include duplicate packet identification information. In an aspect,
the MAC subheader may include a priority, or a time interval for
which a lower priority session should not start.
[0089] In an aspect, the RRC protocol layer in the D2D
communication state configures a MAC layer to generate a MAC CE
including at least a group ID that indicates a D2D communication
group to which the first UE belongs, a source ID that indicates an
ID associated with the first UE, a priority, and/or a time interval
for which a lower priority session should not start.
[0090] At step 1906, the UE monitors one or more radio resources
for an announcement from the at least a second UE that belongs to a
D2D communication group of interest.
[0091] At step 1908. The UE sends an announcement including a MAC
CE to the at least a second UE, the announcement indicating that
the first UE will send a transmission.
[0092] At step 1910, the UE communicates with at least the second
UE.
[0093] It should be understood that the steps indicated by dotted
lines in FIG. 19 (e.g., steps 1902, 1906, and 1908) are optional
steps. For example, steps 1904 and 1910 may be performed without
performing steps 1902, 1906, and 1908. As another example, steps
1902, 1904 and 1910 may be performed without performing steps 1906
and 1908.
[0094] FIG. 20 is a conceptual data flow diagram 2000 illustrating
the data flow between different modules/means/components in an
exemplary apparatus 2002. The apparatus may be a UE (also referred
to as a first UE). The apparatus includes a module 2004 that
receives D2D communications from another UE (e.g., UE 2050), a
module 2006 that initiates an application for D2D communication, a
module 2008 that configures a NAS protocol layer and/or an RRC
protocol layer to enable D2D communication with at least a second
UE when the first UE is out of network coverage, a module 2010 that
communicates with at least the second UE, a module 2102 that
monitors one or more radio resources for an announcement from the
at least a second UE that belongs to a D2D communication group of
interest, a module 2014 that sends an announcement including a MAC
CE to at least the second UE, the announcement indicating that the
first UE will send a transmission, and a module 2016 for sending
D2D transmissions to another UE (e.g., UE 2050).
[0095] The apparatus may include additional modules that perform
each of the steps of the algorithm in the aforementioned flow chart
of FIG. 19. As such, each step in the aforementioned flow chart of
FIG. 19 may be performed by a module and the apparatus may include
one or more of those modules. The modules may be one or more
hardware components specifically configured to carry out the stated
processes/algorithm, implemented by a processor configured to
perform the stated processes/algorithm, stored within a
computer-readable medium for implementation by a processor, or some
combination thereof.
[0096] FIG. 21 is a diagram 2100 illustrating an example of a
hardware implementation for an apparatus 2002' employing a
processing system 2114. The processing system 2114 may be
implemented with a bus architecture, represented generally by the
bus 2124. The bus 2124 may include any number of interconnecting
buses and bridges depending on the specific application of the
processing system 2114 and the overall design constraints. The bus
2124 links together various circuits including one or more
processors and/or hardware modules, represented by the processor
2104, the modules 2004, 2006, 2008, 2010, 2012, 2014, and 2016, and
the computer-readable medium/memory 2106. The bus 2124 may also
link various other circuits such as timing sources, peripherals,
voltage regulators, and power management circuits, which are well
known in the art, and therefore, will not be described any
further.
[0097] The processing system 2114 may be coupled to a transceiver
2110. The transceiver 2110 is coupled to one or more antennas 2120.
The transceiver 2110 provides a means for communicating with
various other apparatus over a transmission medium. The transceiver
2110 receives a signal from the one or more antennas 2120, extracts
information from the received signal, and provides the extracted
information to the processing system 2114, specifically the
receiving module 2004. In addition, the transceiver 2110 receives
information from the processing system 2114, specifically the
transmission module 2016, and based on the received information,
generates a signal to be applied to the one or more antennas 2120.
The processing system 2114 includes a processor 2104 coupled to a
computer-readable medium/memory 2106. The processor 2104 is
responsible for general processing, including the execution of
software stored on the computer-readable medium/memory 2106. The
software, when executed by the processor 2104, causes the
processing system 2114 to perform the various functions described
supra for any particular apparatus. The computer-readable
medium/memory 2106 may also be used for storing data that is
manipulated by the processor 2104 when executing software. The
processing system further includes at least one of the modules
2004, 2006, 2008, 2010, 2012, 2014, and 2016. The modules may be
software modules running in the processor 2104, resident/stored in
the computer readable medium/memory 2106, one or more hardware
modules coupled to the processor 2104, or some combination thereof.
The processing system 2114 may be a component of the UE 650 and may
include the memory 660 and/or at least one of the TX processor 668,
the RX processor 656, and the controller/processor 659.
[0098] In one configuration, the apparatus 2002/2002' for wireless
communication includes means for initiating an application for the
D2D communication, means for configuring a NAS protocol layer
and/or an RRC protocol layer to enable D2D communication with at
least a second UE when the first UE is out of network coverage,
means for monitoring one or more radio resources for an
announcement from the at least a second UE that belongs to a D2D
communication group of interest, means for sending an announcement
including a MAC CE to the at least a second UE, and means for
communicating with the at least a second UE. The aforementioned
means may be one or more of the aforementioned modules of the
apparatus 2002 and/or the processing system 2114 of the apparatus
2002' configured to perform the functions recited by the
aforementioned means. As described supra, the processing system
2114 may include the TX Processor 668, the RX Processor 656, and
the controller/processor 659. As such, in one configuration, the
aforementioned means may be the TX Processor 668, the RX Processor
656, and the controller/processor 659 configured to perform the
functions recited by the aforementioned means.
[0099] It is understood that the specific order or hierarchy of
steps in the processes disclosed is an illustration of exemplary
approaches. Based upon design preferences, it is understood that
the specific order or hierarchy of steps in the processes may be
rearranged. Further, some steps may be combined or omitted. The
accompanying method claims present elements of the various steps in
a sample order, and are not meant to be limited to the specific
order or hierarchy presented.
[0100] The previous description is provided to enable any person
skilled in the art to practice the various aspects described
herein. Various modifications to these aspects will be readily
apparent to those skilled in the art, and the generic principles
defined herein may be applied to other aspects. Thus, the claims
are not intended to be limited to the aspects shown herein, but is
to be accorded the full scope consistent with the language claims,
wherein reference to an element in the singular is not intended to
mean "one and only one" unless specifically so stated, but rather
"one or more." The word "exemplary" is used herein to mean "serving
as an example, instance, or illustration." Any aspect described
herein as "exemplary" is not necessarily to be construed as
preferred or advantageous over other aspects." Unless specifically
stated otherwise, the term "some" refers to one or more.
Combinations such as "at least one of A, B, or C," "at least one of
A, B, and C," and "A, B, C, or any combination thereof" include any
combination of A, B, and/or C, and may include multiples of A,
multiples of B, or multiples of C. Specifically, combinations such
as "at least one of A, B, or C," "at least one of A, B, and C," and
"A, B, C, or any combination thereof" may be A only, B only, C
only, A and B, A and C, B and C, or A and B and C, where any such
combinations may contain one or more member or members of A, B, or
C. All structural and functional equivalents to the elements of the
various aspects described throughout this disclosure that are known
or later come to be known to those of ordinary skill in the art are
expressly incorporated herein by reference and are intended to be
encompassed by the claims. Moreover, nothing disclosed herein is
intended to be dedicated to the public regardless of whether such
disclosure is explicitly recited in the claims. No claim element is
to be construed as a means plus function unless the element is
expressly recited using the phrase "means for."
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