U.S. patent application number 16/453818 was filed with the patent office on 2020-01-02 for method and apparatus of handling sidelink reception in a wireless communication system.
The applicant listed for this patent is ASUSTek Computer Inc.. Invention is credited to Wei-Yu Chen, Ming-Che Li, Li-Te Pan, Li-Chih Tseng.
Application Number | 20200008266 16/453818 |
Document ID | / |
Family ID | 67139606 |
Filed Date | 2020-01-02 |
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United States Patent
Application |
20200008266 |
Kind Code |
A1 |
Pan; Li-Te ; et al. |
January 2, 2020 |
METHOD AND APPARATUS OF HANDLING SIDELINK RECEPTION IN A WIRELESS
COMMUNICATION SYSTEM
Abstract
A method and apparatus are disclosed from the perspective of a
UE (User Equipment). In one embodiment, the method includes setting
a state variable used for the sidelink transmission to "1" when a
PDCP (Packet Data Convergence Protocol) entity for the sidelink
radio bearer is established. The method also includes performing
the sidelink transmission for a very first data unit of the PDCP
entity on the sidelink radio bearer, wherein a sequence number of
the very first data unit is set to the state variable.
Inventors: |
Pan; Li-Te; (Taipei City,
TW) ; Tseng; Li-Chih; (Taipei City, TW) ;
Chen; Wei-Yu; (Taipei City, TW) ; Li; Ming-Che;
(Taipei City, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ASUSTek Computer Inc. |
Taipei City |
|
TW |
|
|
Family ID: |
67139606 |
Appl. No.: |
16/453818 |
Filed: |
June 26, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62692540 |
Jun 29, 2018 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 4/40 20180201; H04W
80/02 20130101; H04W 80/08 20130101; H04W 92/18 20130101; H04L
1/1642 20130101; H04W 76/14 20180201; H04W 88/02 20130101; H04W
76/30 20180201; H04W 28/06 20130101 |
International
Class: |
H04W 80/08 20060101
H04W080/08; H04L 1/16 20060101 H04L001/16; H04W 76/14 20060101
H04W076/14; H04W 92/18 20060101 H04W092/18; H04W 4/40 20060101
H04W004/40; H04W 80/02 20060101 H04W080/02 |
Claims
1. A method for a UE (User Equipment) to perform sidelink
transmission on a sidelink radio bearer, comprising: setting a
state variable used for the sidelink transmission to "1" when a
PDCP (Packet Data Convergence Protocol) entity for the sidelink
radio bearer is established; and performing the sidelink
transmission for a very first data unit of the PDCP entity on the
sidelink radio bearer, wherein a sequence number of the very first
data unit is set to the state variable.
2. The method of claim 1, further comprising: setting the state
variable to "1" if duplication is enable on the sidelink radio
bearer.
3. The method of claim 1, further comprising: setting the state
variable to "0" if duplication is disable on the sidelink radio
bearer.
4. The method of claim 1, further comprising: establishing a first
logical channel and a second logical channel, wherein the first
logical channel and the second logical channel are associated with
the sidelink radio bearer.
5. The method of claim 4, further comprising: generating a
duplicated data unit, wherein the duplicated data unit is a
duplicate of the very first data unit; and delivering the very
first data unit to the first logical channel and the duplicated
data unit to the second logical channel for the sidelink
transmission.
6. The method of claim 5, wherein the duplicated data unit is a
PDCP PDU (Protocol Data Unit).
7. The method of claim 1, wherein the state variable is
Next_PDCP_TX_SN.
8. The method of claim 1, wherein the sequence number is a PDCP
sequence number.
9. The method of claim 1, wherein the data unit is a PDCP PDU
(Protocol Data Unit).
10. A User Equipment (UE) to perform sidelink transmission on a
sidelink radio bearer, comprising: a control circuit; a processor
installed in the control circuit; and a memory installed in the
control circuit and operatively coupled to the processor; wherein
the processor is configured to execute a program code stored in the
memory to: set a state variable used for the sidelink transmission
to "1" when a PDCP (Packet Data Convergence Protocol) entity for
the sidelink radio bearer is established; and perform the sidelink
transmission for a very first data unit of the PDCP entity on the
sidelink radio bearer, wherein a sequence number of the very first
data unit is set to the state variable.
11. The UE of claim 10, wherein the processor is configured to
execute a program code stored in the memory to: set the state
variable to "1" if duplication is enable on the sidelink radio
bearer.
12. The UE of claim 10, wherein the processor is configured to
execute a program code stored in the memory to: set the state
variable to "0" if duplication is disable on the sidelink radio
bearer.
13. The UE of claim 10, wherein the processor is configured to
execute a program code stored in the memory to: establish a first
logical channel and a second logical channel, wherein the first
logical channel and the second logical channel are associated with
the sidelink radio bearer.
14. The UE of claim 10, wherein the processor is configured to
execute a program code stored in the memory to: generate a
duplicated data unit, wherein the duplicated data unit is a
duplicate of the very first data unit; and deliver the very first
data unit to the first logical channel and the duplicated data unit
to the second logical channel for the sidelink transmission.
15. The UE of claim 14, wherein the duplicated data unit is a PDCP
PDU (Protocol Data Unit).
16. The UE of claim 10, wherein the state variable is
Next_PDCP_TX_SN.
17. The UE of claim 10, wherein the sequence number is a PDCP
sequence number.
18. The UE of claim 10, wherein the data unit is a PDCP PDU
(Protocol Data Unit).
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims the benefit of U.S.
Provisional Patent Application Ser. No. 62/692,540 filed on Jun.
29, 2018, the entire disclosure of which is incorporated herein in
its entirety by reference.
FIELD
[0002] This disclosure generally relates to wireless communication
networks, and more particularly, to a method and apparatus of
handling sidelink reception in a wireless communication system.
BACKGROUND
[0003] With the rapid rise in demand for communication of large
amounts of data to and from mobile communication devices,
traditional mobile voice communication networks are evolving into
networks that communicate with Internet Protocol (IP) data packets.
Such IP data packet communication can provide users of mobile
communication devices with voice over IP, multimedia, multicast and
on-demand communication services.
[0004] An exemplary network structure is an Evolved Universal
Terrestrial Radio Access Network (E-UTRAN). The E-UTRAN system can
provide high data throughput in order to realize the above-noted
voice over IP and multimedia services. A new radio technology for
the next generation (e.g., 5G) is currently being discussed by the
3GPP standards organization. Accordingly, changes to the current
body of 3GPP standard are currently being submitted and considered
to evolve and finalize the 3GPP standard.
SUMMARY
[0005] A method and apparatus are disclosed from the perspective of
a UE (User Equipment). In one embodiment, the method includes
setting a state variable used for the sidelink transmission to "1"
when a PDCP (Packet Data Convergence Protocol) entity for the
sidelink radio bearer is established. The method also includes
performing the sidelink transmission for a very first data unit of
the PDCP entity on the sidelink radio bearer, wherein a sequence
number of the very first data unit is set to the state
variable.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 shows a diagram of a wireless communication system
according to one exemplary embodiment.
[0007] FIG. 2 is a block diagram of a transmitter system (also
known as access network) and a receiver system (also known as user
equipment or UE) according to one exemplary embodiment.
[0008] FIG. 3 is a functional block diagram of a communication
system according to one exemplary embodiment.
[0009] FIG. 4 is a functional block diagram of the program code of
FIG. 3 according to one exemplary embodiment.
[0010] FIG. 5 is a reproduction of Figure 6-3 of 3GPP TS 36.300 v
15.1.0.
[0011] FIG. 6 is a reproduction of Figure 23.10.2.1-1 of 3GPP TS
36.300 v 15.1.0.
[0012] FIG. 7 is a reproduction of Figure 23.10.2.2-1 of 3GPP TS
36.300 v 15.1.0.
[0013] FIG. 8 is a reproduction of Figure 23.10.2.2-2 of 3GPP TS
36.300 v 15.1.0.
[0014] FIG. 9 is a reproduction of Figure 6.4-x of 3GPP
R2-1809265.
[0015] FIG. 10 is a reproduction of Table 6.2.4-1 of 3GPP
R2-1808916.
[0016] FIG. 11 is a reproduction of Table 6.2.4-2 of 3GPP
R2-1808916.
[0017] FIG. 12 is a diagram according to one exemplary
embodiment.
[0018] FIG. 13 is a diagram according to one exemplary
embodiment.
[0019] FIG. 14 is a diagram according to one exemplary
embodiment.
[0020] FIG. 15 is a diagram according to one exemplary
embodiment.
[0021] FIG. 16 is a diagram according to one exemplary
embodiment.
[0022] FIG. 17 is a diagram according to one exemplary
embodiment.
[0023] FIG. 18 is a flow chart according to one exemplary
embodiment.
[0024] FIG. 19 is a flow chart according to one exemplary
embodiment.
[0025] FIG. 20 is a flow chart according to one exemplary
embodiment.
[0026] FIG. 21 is a flow chart according to one exemplary
embodiment.
DETAILED DESCRIPTION
[0027] The exemplary wireless communication systems and devices
described below employ a wireless communication system, supporting
a broadcast service. Wireless communication systems are widely
deployed to provide various types of communication such as voice,
data, and so on. These systems may be based on code division
multiple access (CDMA), time division multiple access (TDMA),
orthogonal frequency division multiple access (OFDMA), 3GPP LTE
(Long Term Evolution) wireless access, 3GPP LTE-A or LTE-Advanced
(Long Term Evolution Advanced), 3GPP2 UMB (Ultra Mobile Broadband),
WiMax, 3GPP NR (New Radio), or some other modulation
techniques.
[0028] In particular, the exemplary wireless communication systems
devices described below may be designed to support one or more
standards such as the standard offered by a consortium named "3rd
Generation Partnership Project" referred to herein as 3GPP,
including: TS 36.300 v15.1.0, "Evolved Universal Terrestrial Radio
Access (E-UTRA); Overall description; Stage 2"; TS 36.323 v14.5.0,
"Evolved Universal Terrestrial Radio Access (E-UTRA); Packet Data
Convergence Protocol (PDCP) specification"; R2-1809265,
"Introduction of eV2X in TS 36.300"; R2-1808916, "Introduction of
eV2X in 36.321"; R2-1808921, "Introduction of V2X duplication to TS
36.323"; and R2-1808917, "Introduction of eV2X in TS 36.331". The
standards and documents listed above are hereby expressly
incorporated by reference in their entirety.
[0029] FIG. 1 shows a multiple access wireless communication system
according to one embodiment of the invention. An access network 100
(AN) includes multiple antenna groups, one including 104 and 106,
another including 108 and 110, and an additional including 112 and
114. In FIG. 1, only two antennas are shown for each antenna group,
however, more or fewer antennas may be utilized for each antenna
group. Access terminal 116 (AT) is in communication with antennas
112 and 114, where antennas 112 and 114 transmit information to
access terminal 116 over forward link 120 and receive information
from access terminal 116 over reverse link 118. Access terminal
(AT) 122 is in communication with antennas 106 and 108, where
antennas 106 and 108 transmit information to access terminal (AT)
122 over forward link 126 and receive information from access
terminal (AT) 122 over reverse link 124. In a FDD system,
communication links 118, 120, 124 and 126 may use different
frequency for communication. For example, forward link 120 may use
a different frequency then that used by reverse link 118.
[0030] Each group of antennas and/or the area in which they are
designed to communicate is often referred to as a sector of the
access network. In the embodiment, antenna groups each are designed
to communicate to access terminals in a sector of the areas covered
by access network 100.
[0031] In communication over forward links 120 and 126, the
transmitting antennas of access network 100 may utilize beamforming
in order to improve the signal-to-noise ratio of forward links for
the different access terminals 116 and 122. Also, an access network
using beamforming to transmit to access terminals scattered
randomly through its coverage causes less interference to access
terminals in neighboring cells than an access network transmitting
through a single antenna to all its access terminals.
[0032] An access network (AN) may be a fixed station or base
station used for communicating with the terminals and may also be
referred to as an access point, a Node B, a base station, an
enhanced base station, an evolved Node B (eNB), or some other
terminology. An access terminal (AT) may also be called user
equipment (UE), a wireless communication device, terminal, access
terminal or some other terminology.
[0033] FIG. 2 is a simplified block diagram of an embodiment of a
transmitter system 210 (also known as the access network) and a
receiver system 250 (also known as access terminal (AT) or user
equipment (UE)) in a MIMO system 200. At the transmitter system
210, traffic data for a number of data streams is provided from a
data source 212 to a transmit (TX) data processor 214.
[0034] In one embodiment, each data stream is transmitted over a
respective transmit antenna. TX data processor 214 formats, codes,
and interleaves the traffic data for each data stream based on a
particular coding scheme selected for that data stream to provide
coded data.
[0035] The coded data for each data stream may be multiplexed with
pilot data using OFDM techniques. The pilot data is typically a
known data pattern that is processed in a known manner and may be
used at the receiver system to estimate the channel response. The
multiplexed pilot and coded data for each data stream is then
modulated (i.e., symbol mapped) based on a particular modulation
scheme (e.g., BPSK, QPSK, M-PSK, or M-QAM) selected for that data
stream to provide modulation symbols. The data rate, coding, and
modulation for each data stream may be determined by instructions
performed by processor 230.
[0036] The modulation symbols for all data streams are then
provided to a TX MIMO processor 220, which may further process the
modulation symbols (e.g., for OFDM). TX MIMO processor 220 then
provides N.sub.T modulation symbol streams to N.sub.T transmitters
(TMTR) 222a through 222t. In certain embodiments, TX MIMO processor
220 applies beamforming weights to the symbols of the data streams
and to the antenna from which the symbol is being transmitted.
[0037] Each transmitter 222 receives and processes a respective
symbol stream to provide one or more analog signals, and further
conditions (e.g., amplifies, filters, and upconverts) the analog
signals to provide a modulated signal suitable for transmission
over the MIMO channel. N.sub.T modulated signals from transmitters
222a through 222t are then transmitted from N.sub.T antennas 224a
through 224t, respectively.
[0038] At receiver system 250, the transmitted modulated signals
are received by N.sub.R antennas 252a through 252r and the received
signal from each antenna 252 is provided to a respective receiver
(RCVR) 254a through 254r. Each receiver 254 conditions (e.g.,
filters, amplifies, and downconverts) a respective received signal,
digitizes the conditioned signal to provide samples, and further
processes the samples to provide a corresponding "received" symbol
stream.
[0039] An RX data processor 260 then receives and processes the
N.sub.R received symbol streams from N.sub.R receivers 254 based on
a particular receiver processing technique to provide N.sub.T
"detected" symbol streams. The RX data processor 260 then
demodulates, deinterleaves, and decodes each detected symbol stream
to recover the traffic data for the data stream. The processing by
RX data processor 260 is complementary to that performed by TX MIMO
processor 220 and TX data processor 214 at transmitter system
210.
[0040] A processor 270 periodically determines which pre-coding
matrix to use (discussed below). Processor 270 formulates a reverse
link message comprising a matrix index portion and a rank value
portion.
[0041] The reverse link message may comprise various types of
information regarding the communication link and/or the received
data stream. The reverse link message is then processed by a TX
data processor 238, which also receives traffic data for a number
of data streams from a data source 236, modulated by a modulator
280, conditioned by transmitters 254a through 254r, and transmitted
back to transmitter system 210.
[0042] At transmitter system 210, the modulated signals from
receiver system 250 are received by antennas 224, conditioned by
receivers 222, demodulated by a demodulator 240, and processed by a
RX data processor 242 to extract the reserve link message
transmitted by the receiver system 250. Processor 230 then
determines which pre-coding matrix to use for determining the
beamforming weights then processes the extracted message.
[0043] Turning to FIG. 3, this figure shows an alternative
simplified functional block diagram of a communication device
according to one embodiment of the invention. As shown in FIG. 3,
the communication device 300 in a wireless communication system can
be utilized for realizing the UEs (or ATs) 116 and 122 in FIG. 1 or
the base station (or AN) 100 in FIG. 1, and the wireless
communications system is preferably the NR system. The
communication device 300 may include an input device 302, an output
device 304, a control circuit 306, a central processing unit (CPU)
308, a memory 310, a program code 312, and a transceiver 314. The
control circuit 306 executes the program code 312 in the memory 310
through the CPU 308, thereby controlling an operation of the
communications device 300. The communications device 300 can
receive signals input by a user through the input device 302, such
as a keyboard or keypad, and can output images and sounds through
the output device 304, such as a monitor or speakers. The
transceiver 314 is used to receive and transmit wireless signals,
delivering received signals to the control circuit 306, and
outputting signals generated by the control circuit 306 wirelessly.
The communication device 300 in a wireless communication system can
also be utilized for realizing the AN 100 in FIG. 1.
[0044] FIG. 4 is a simplified block diagram of the program code 312
shown in FIG. 3 in accordance with one embodiment of the invention.
In this embodiment, the program code 312 includes an application
layer 400, a Layer 3 portion 402, and a Layer 2 portion 404, and is
coupled to a Layer 1 portion 406. The Layer 3 portion 402 generally
performs radio resource control. The Layer 2 portion 404 generally
performs link control. The Layer 1 portion 406 generally performs
physical connections.
[0045] 3GPP TS 36.300 describes related sidelink operation as
follows:
6 Layer 2
[0046] Layer 2 is split into the following sublayers: Medium Access
Control (MAC), Radio Link Control (RLC) and Packet Data Convergence
Protocol (PDCP). This subclause gives a high level description of
the Layer 2 sub-layers in terms of services and functions. The
three figures below depict the PDCP/RLC/MAC architecture for
downlink, uplink and Sidelink, where: [0047] Service Access Points
(SAP) for peer-to-peer communication are marked with circles at the
interface between sublayers. The SAP between the physical layer and
the MAC sublayer provides the transport channels. The SAPs between
the MAC sublayer and the RLC sublayer provide the logical channels.
[0048] The multiplexing of several logical channels (i.e. radio
bearers) on the same transport channel (i.e. transport block) is
performed by the MAC sublayer; [0049] In both uplink and downlink,
when neither CA nor DC are configured, only one transport block is
generated per TTI in the absence of spatial multiplexing; [0050] In
Sidelink, only one transport block is generated per TTI. [0051]
[Figure 6-1, entitled "Layer 2 Structure for DL", is omitted]
[0052] [Figure 6-2: entitled "Layer 2 Structure for UL" is omitted]
[0053] NOTE 1: The eNB may not be able to guarantee that a L2
buffer overflow will never occur. If such overflow occurs, UE may
discard packets in the L2 buffer. [0054] NOTE 2: For a NB-IoT UE
that only supports Control Plane CIoT EPS optimizations, as defined
in TS 24.301 [20], PDCP is bypassed. For a NB-IoT UE that supports
Control Plane CIoT EPS optimization and S1-U data transfer or User
Plane CIoT EPS optimization, as defined in TS 24.301 [20], PDCP is
also bypassed (i.e. not used) until AS security is activated.
[Figure 6-3 of 3GPP TS 36.300 v 15.1.0, entitled "Layer 2 Structure
for Sidelink", is reproduced as FIG. 5] [ . . . ]
23.10 Support for Sidelink Communication
23.10.1 General
[0055] Sidelink communication is a mode of communication whereby
UEs can communicate with each other directly over the PC5 interface
[62]. This communication mode is supported when the UE is served by
E-UTRAN and when the UE is outside of E-UTRA coverage. Only those
UEs authorised to be used for public safety operation can perform
sidelink communication. In order to perform synchronisation for out
of coverage operation UE(s) may act as a synchronisation source by
transmitting SBCCH and a synchronisation signal. SBCCH carries the
most essential system information needed to receive other sidelink
channels and signals. SBCCH along with a synchronisation signal is
transmitted with a fixed periodicity of 40 ms. When the UE is in
network coverage, the contents of SBCCH are derived from the
parameters signalled by the eNB. When the UE is out of coverage, if
the UE selects another UE as a synchronisation reference, then the
content of SBCCH is derived from the received SBCCH; otherwise UE
uses pre-configured parameters. SIB18 provides the resource
information for synchronisation signal and SBCCH transmission.
There are two pre-configured subframes every 40 ms for out of
coverage operation. UE receives synchronisation signal and SBCCH in
one subframe and transmit synchronisation signal and SBCCH on
another subframe if UE becomes synchronisation source based on
defined criterion [16]. UE performs sidelink communication on
subframes defined over the duration of Sidelink Control period. The
Sidelink Control period is the period over which resources
allocated in a cell for sidelink control information and sidelink
data transmissions occur. Within the Sidelink Control period the UE
sends sidelink control information followed by sidelink data.
Sidelink control information indicates a Layer 1 ID and
characteristics of the transmissions (e.g. MCS, location of the
resource(s) over the duration of Sidelink Control period, timing
alignment). The UE performs transmission and reception over Uu and
PC5 with the following decreasing priority order in case Sidelink
Discovery Gap is not configured: [0056] Uu transmission/reception
(highest priority); [0057] PC5 sidelink communication
transmission/reception; [0058] PC5 sidelink discovery
announcement/monitoring (lowest priority). The UE performs
transmission and reception over Uu and PC5 with the following
decreasing priority order in case Sidelink Discovery Gap is
configured: [0059] Uu transmission/reception for RACH; [0060] PC5
sidelink discovery announcement during a Sidelink Discovery Gap for
transmission; [0061] Non-RACH Uu transmission; [0062] PC5 sidelink
discovery monitoring during a Sidelink Discovery Gap for reception;
[0063] Non-RACH Uu reception; [0064] PC5 sidelink communication
transmission/reception.
23.10.2 Radio Protocol Architecture
[0065] In this subclause, the UE radio protocol architecture for
sidelink communication is given for the user plane and the control
plane.
23.10.2.1 User Plane
[0066] Figure 23.10.2.1-1 shows the protocol stack for the user
plane, where PDCP, RLC and MAC sublayers (terminate at the other
UE) perform the functions listed for the user plane in subclause 6.
The Access Stratum protocol stack in the PC5 interface consists of
PDCP, RLC, MAC and PHY as shown below in Figure 23.10.2.1-1.
[Figure 23.10.2.1-1 of 3GPP TS 36.300 v 15.1.0, entitled
"User-Plane protocol stack for sidelink communication", is
reproduced as FIG. 6] User plane details of sidelink communication:
[0067] There is no HARQ feedback for sidelink communication; [0068]
RLC UM is used for sidelink communication; [0069] A receiving UE
needs to maintain at least one RLC UM entity per transmitting peer
UE; [0070] A receiving RLC UM entity used for sidelink
communication does not need to be configured prior to reception of
the first RLC UMD PDU; [0071] ROHC Unidirectional Mode is used for
header compression in PDCP for sidelink communication. A UE may
establish multiple logical channels. LCID included within the MAC
subheader uniquely identifies a logical channel within the scope of
one Source Layer-2 ID and Destination Layer-2 ID combination.
Parameters for logical channel prioritization are not configured.
The Access stratum (AS) is provided with the PPPP of a protocol
data unit transmitted over PC5 interface by higher layer. There is
a PPPP associated with each logical channel.
23.10.2.2 Control Plane
[0072] A UE does not establish and maintain a logical connection to
receiving UEs prior to one-to-many a sidelink communication. Higher
layer establishes and maintains a logical connection for one-to-one
sidelink communication including ProSe UE-to-Network Relay
operation. The Access Stratum protocol stack for SBCCH in the PC5
interface consists of RRC, RLC, MAC and PHY as shown below in
Figure 23.10.2.2-1. [0073] [Figure 23.10.2.2-1 of 3GPP TS 36.300 v
15.1.0, entitled "Control-Plane protocol stack for SBCCH", is
reproduced as FIG. 7] The control plane for establishing,
maintaining and releasing the logical connection for one-to-one
sidelink communication is shown in Figure 23.10.2.2-2. [Figure
23.10.2.2-2 of 3GPP TS 36.300 v 15.1.0, entitled "Control-Plane
protocol stack for one-to-one sidelink communication", is
reproduced as FIG. 8] [ . . . ]
23.14 Support for V2X Services
23.14.1 General
[0074] Vehicular communication services, represented by V2X
services, can consist of the following four different types: V2V,
V2I, V2N and V2P [71]. V2X services can be provided by PC5
interface and/or Uu interface. Support of V2X services via PC5
interface is provided by V2X sidelink communication, which is a
mode of communication whereby UEs can communicate with each other
directly over the PC5 interface [62]. This communication mode is
supported when the UE is served by E-UTRAN and when the UE is
outside of E-UTRA coverage. Only the UEs authorised to be used for
V2X services can perform V2X sidelink communication.
23.14.1.1 Support for V2X Sidelink Communication
[0075] The user plane protocol stack and functions, as specified in
subclause 23.10.2.1 for sidelink communication, are also used for
V2X sidelink communication. In addition, for V2X sidelink
communication: [0076] STCH for sidelink communication is also used
for V2X sidelink communication. [0077] Non-V2X (e.g. Public Safety)
data is not multiplexed with V2X data transmitted in resources
configured for V2X sidelink communication. [0078] The Access
Stratum (AS) is provided with the PPPP of a protocol data unit
transmitted over PC5 interface by upper layers. The packet delay
budget (PDB) of the protocol data unit can be determined from the
PPPP. The low PDB is mapped to the high priority PPPP value [72].
[0079] The existing logical channel prioritization based on PPPP is
used for V2X sidelink communication. Control plane protocol stack
for SBCCH as specified in subclause 23.10.2.2 for sidelink
communication is also used for V2X sidelink communication. The UE
supporting V2X sidelink communication can operate in two modes for
resource allocation: [0080] Scheduled resource allocation,
characterized by: [0081] The UE needs to be RRC_CONNECTED in order
to transmit data; [0082] The UE requests transmission resources
from the eNB. The eNB schedules transmission resources for
transmission of sidelink control information and data. Sidelink SPS
is supported for scheduled resource allocation; [0083] UE
autonomous resource selection, characterized by: [0084] The UE on
its own selects resources from resource pools and performs
transport format selection to transmit sidelink control information
and data; [0085] If mapping between the zones and V2X sidelink
transmission resource pools is configured, the UE selects V2X
sidelink resource pool based on the zone UE is located in. [0086]
The UE performs sensing for (re)selection of sidelink resources.
Based on sensing results, the UE (re)selects some specific sidelink
resources and reserves multiple sidelink resources. Up to 2
parallel independent resource reservation processes are allowed to
be performed by the UE. The UE is also allowed to perform a single
resource selection for its V2X sidelink transmission. In order to
assist the eNB to provide sidelink resources, the UE in
RRC_CONNECTED may report geographical location information to the
eNB. The eNB can configure the UE to report the complete UE
geographical location information based on periodic reporting via
the existing measurement report signaling. Geographical zones can
be configured by the eNB or pre-configured. When zones are
(pre)configured, the world is divided into geographical zones using
a single fixed reference point (i.e. geographical coordinates (0,
0)), length and width. The UE determines the zone identity by means
of modulo operation using length and width of each zone, number of
zones in length, number of zones in width, the single fixed
reference point and the geographical coordinates of the UE's
current location. The length and width of each zone, number of
zones in length and number of zones in width are provided by the
eNB when the UE is in coverage and pre-configured when the UE is
out of coverage. The zone is configurable for both in coverage and
out of coverage.
[0087] For in coverage UE, when the UE uses UE autonomous resource
selection, the eNB can provide the mapping between zone(s) and V2X
sidelink transmission resource pools in RRC signalling. For out of
coverage UEs, the mapping between the zone(s) and V2X sidelink
transmission resource pools can be pre-configured. If a mapping
between zone(s) and V2X sidelink transmission resource pool is
(pre-)configured, the UE selects transmission sidelink resources
from the resource pool corresponding to the zone where it is
currently located. The zone concept is not applied to exceptional
V2X sidelink transmission pools as well as reception pools.
Resource pools for V2X sidelink communication are not configured
based on priority.
For V2X sidelink transmission, during handover, transmission
resource pool configurations including exceptional transmission
resource pool for the target cell can be signaled in the handover
command to reduce the transmission interruption. In this way, the
UE may use the V2X sidelink transmission resource pools of the
target cell before the handover is completed as long as either
synchronization is performed with the target cell in case eNB is
configured as synchronization source or synchronization is
performed with GNSS in case GNSS is configured as synchronization
source. If the exceptional transmission resource pool is included
in the handover command, the UE uses randomly selected resources
from the exceptional transmission resource pool, starting from the
reception of handover command. If the UE is configured with
scheduled resource allocation in the handover command, the UE
continues to use the exceptional transmission resource pool while
the timer associated with handover is running. If the UE is
configured with autonomous resource selection in the target cell
the UE continues to use the exceptional transmission resource pool
until the sensing results on the transmission resource pools for
autonomous resource selection are available. For exceptional cases
(e.g. during RLF, during transition from RRC IDLE to RRC CONNECTED
or during change of dedicated V2X sidelink resource pools within a
cell), the UE may select resources in the exceptional pool provided
in serving cell's SIB21 or in dedicated signalling based on random
selection, and uses them temporarily. During cell reselection, the
RRC_IDLE UE may use the randomly selected resources from the
exceptional transmission resource pool of the reselected cell until
the sensing results on the transmission resource pools for
autonomous resource selection are available. In order to avoid
interruption time in receiving V2X messages due to delay in
acquiring reception pools broadcasted from the target cell,
synchronisation configuration and reception resource pool
configuration for the target cell can be signaled to RRC_CONNECTED
UEs in the handover command. For RRC_IDLE UE, it is up to UE
implementation to minimize V2X sidelink transmission/reception
interruption time associated with acquisition of SIB21 of the
target cell. A UE is considered in-coverage on the carrier used for
V2X sidelink communication whenever it detects a cell on that
carrier as per criteria specified in [16]. If the UE that is
authorized for V2X sidelink communication is in-coverage on the
frequency used for V2X sidelink communication or if the eNB
provides V2X sidelink configuration for that frequency (including
the case where UE is out of coverage on that frequency), the UE
uses the scheduled resource allocation or UE autonomous resource
selection as per eNB configuration. When the UE is out of coverage
on the frequency used for V2X sidelink communication and if the eNB
does not provide V2X sidelink configuration for that frequency, the
UE may use a set of transmission and reception resource pools
pre-configured in the UE. V2X sidelink communication resources are
not shared with other non-V2X data transmitted over sidelink. An
RRC_CONNECTED UE may send a Sidelink UE Information message to the
serving cell if it is interested in V2X sidelink communication
transmission in order to request sidelink resources. If the UE is
configured by upper layers to receive V2X sidelink communication
and V2X sidelink reception resource pools are provided, the UE
receives on those provided resources. Reception of V2X sidelink
communication in different carriers/PLMNs can be supported by
having multiple receiver chains in the UE. For sidelink SPS,
maximum 8 SPS configurations with different parameters can be
configured by eNB and all SPS configurations can be active at the
same time. The activation/deactivation of SPS configuration is
signalled via PDCCH by eNB. The existing logical channel
prioritization based on PPPP is used for sidelink SPS. UE
assistance information can be provided to eNB. Reporting of UE
assistance information is configured by eNB for V2X sidelink
communication. The UE assistance information used for V2X sidelink
communication includes traffic characteristic parameters (e.g. a
set of preferred SPS interval, timing offset with respect to
subframe 0 of the SFN 0, PPPP and maximum TB size based on observed
traffic pattern) related to the SPS configuration. The UE
assistance information can be reported in case either SPS is
already configured or not. Triggering of UE assistance information
transmission is left to UE implementation. For instance, the UE is
allowed to report UE assistance information when change in
estimated periodicity and/or timing offset of packet arrival
occurs. SR mask per traffic type is not supported for V2X sidelink
communication. The serving cell can provide synchronization
configuration for the carrier used for V2X sidelink communication.
In this case, the UE follows the synchronization configuration
received from serving cell. In case there is no cell detected on
the carrier used for V2X sidelink communication and the UE does not
receive synchronization configuration from serving cell, the UE
follows preconfigured synchronization configuration. There are
three types of synchronization reference, namely eNB, UE and GNSS.
In case GNSS is configured as synchronization source, the UE
utilizes the UTC time and (pre)configured DFN offset to calculate
direct frame number and subframe number. In case eNB timing is
configured as synchronization reference to the UE, for
synchronization and DL measurements, the UE follows the cell
associated with the concerned frequency (when in-coverage on this
frequency), or the PCell or the serving cell (when out of coverage
on the concerned frequency). UE can indicate the current
synchronization reference type it is using to the eNB. One
transmission pool for scheduled resource allocation is configured,
taking into account the synchronization reference of the UE. For
controlling channel utilization, the network is able to indicate
how the UE adapts its transmission parameters for each transmission
pool depending on the Channel Busy Ratio (CBR). The UE measures all
the configured transmission pools including exceptional pool. If a
pool is (pre)configured such that a UE shall always transmit PSCCH
and PSSCH in adjacent resource blocks the UE measures PSCCH and
PSSCH resources together. If a pool is (pre)configured such that a
UE may transmit PSCCH and the corresponding PSSCH in non-adjacent
resource blocks in a subframe then PSSCH pool and PSCCH pool are
measured separately. A UE in RRC_CONNECTED can be configured to
report CBR measurement results. For CBR reporting, periodic
reporting and event triggered reporting are supported. Two
reporting events are introduced for event-triggered CBR reporting.
In case PSSCH and PSCCH resources are placed non-adjacently, only
PSSCH pool measurement is used for event-triggered CBR reporting.
In case PSSCH and PSCCH resources are placed adjacently, CBR
measurement of both the PSSCH and PSCCH resources is used for
event-triggered CBR reporting. Event-triggered CBR reporting is
triggered by overloaded threshold and/or less-loaded threshold. The
network can configure which of the transmission pools the UE needs
to report. A UE (regardless of its RRC state) performs transmission
parameter adaptation based on the CBR. In case PSSCH and PSCCH
resources are placed non-adjacently, only PSSCH pool measurement is
used for transmission parameter adaptation. In case PSSCH and PSCCH
resources are placed adjacently, CBR measurement of both the PSSCH
and PSCCH resources is used for transmission parameter adaptation.
When CBR measurements are not available, the default transmission
parameters are used. The exemplary adapted transmission parameters
include maximum transmission power, range of the number of
retransmission per TB, range of PSSCH RB number, range of MCS,
maximum limit on channel occupancy ratio. The transmission
parameter adaption applies to all transmission pools including
exceptional pool. For V2X sidelink communication, sidelink
transmission and/or reception resources including exceptional pool
for different frequencies for scheduled resource allocation and UE
autonomous resource selection may be provided. The sidelink
resources for different frequencies can be provided via dedicated
signalling, SIB21 and/or preconfiguration. The serving cell may
indicate to the UE only the frequency on which the UE may acquire
the resource configuration for V2X sidelink communication. If
multiple frequencies and associated resource information are
provided, it is up to UE implementation to select the frequency
among the provided frequencies. The UE shall not use preconfigured
transmission resource if the UE detects a cell providing resource
configuration or inter-carrier resource configuration for V2X
sidelink communication. Frequencies which may provide V2X sidelink
communication resource configuration or cross-carrier configuration
can be signalled in SIB21 or pre-configured in the UE. The RRC_IDLE
UE may prioritize the frequency that provides cross-carrier
resource configuration for V2X sidelink communication during cell
reselection. If the UE supports multiple transmission chains, it
may simultaneously transmit on multiple carriers via PC5. For the
case where multiple frequencies for V2X are supported, a mapping
between V2X service types and V2X frequencies is configured by
upper layers. The UE should ensure a V2X service to be transmitted
on the corresponding frequency. For scheduled resource allocation,
the eNB can schedule a V2X transmission on a frequency based on the
Sidelink BSR [13], in which the UE includes the Destination Index
uniquely associated with a frequency reported by the UE to the eNB
in Sidelink UE Information message as specified in 3GPP TS 36.331
[16]. The UE may receive the V2X sidelink communication of other
PLMNs. The serving cell can indicate to the UE the resource
configuration for V2X sidelink communication reception for
inter-PLMN operation directly or only the frequency on which the UE
may acquire the inter-PLMN resource configuration for V2X sidelink
communication reception. V2X sidelink communication transmission in
other PLMNs is not allowed. When UL transmission overlaps in time
domain with V2X sidelink transmission in the same frequency, the UE
prioritizes the V2X sidelink transmission over the UL transmission
if the PPPP of sidelink MAC PDU is lower than a (pre)configured
PPPP threshold; otherwise, the UE prioritizes the UL transmission
over the V2X sidelink transmission. When UL transmission overlaps
in time domain with V2X sidelink transmission in different
frequency, the UE may prioritize the V2X sidelink transmission over
the UL transmission or reduce UL transmission power if the PPPP of
sidelink MAC PDU is lower than a (pre)configured PPPP threshold;
otherwise, the UE prioritizes the UL transmission over the V2X
sidelink transmission or reduces V2X sidelink transmission power.
However, if UL transmission is prioritized by upper layer as
specified in 3GPP TS 24.386 [75] or random access procedure is
performed, the UE prioritizes UL transmission over any V2X sidelink
transmission (i.e. irrespectively of the sidelink MAC PDU's PPPP).
Resource pool for transmission of pedestrian UE (P-UE) may be
overlapped with resources for V2X sidelink communication. For each
transmission pool, resource selection mechanism (i.e. random
selection, partial sensing based selection or either random
selection or partial sensing based selection), which is allowed to
be used in this pool, is also configured. If P-UE is configured to
use either random selection or partial sensing based selection for
one transmission pool, it is up to UE implementation to select a
specific resource selection mechanism. If the P-UE is configured to
use partial sensing based selection only, the P-UE shall use
partial sensing based selection in the pool. The P-UE shall not do
random selection in the pool wherein only partial sensing is
allowed. If the eNB does not provide a random selection pool, the
P-UEs that support only random selection cannot perform sidelink
transmission. In exceptional pool, the P-UE uses random selection.
The P-UE can send Sidelink UE Information message to indicate that
it requests resource pools for P2X-related V2X sidelink
communication transmission as specified in 3GPP TS 36.331 [16]. It
is not mandatory for P-UE to support zone based resource selection.
The P-UE reports whether it supports zone based resource selection
as part of UE capability signalling. If the P-UE supports zone
based resource selection, the network can provide zone based
configuration via only dedicated signalling. Power saving of P-UE
can be achieved by UE implementation and upper layer mechanisms.
P-UE does not perform CBR measurement. However, P-UE adjusts the
transmission parameters based on the default transmission parameter
configuration, which can be provided to the P-UE via RRC
signalling. To support the co-existence of CEN DSRC and V2X
sidelink communication, the upper layers of the UE which is
performing V2X sidelink communication send an indication to lower
layers when the UE is within the proximity of CEN DSRC tolling
station(s).
[0088] 3GPP R2-1809265 introduces the following descriptions and
concepts:
6.4 Carrier Aggregation
[0089] In case of CA, the multi-carrier nature of the physical
layer is only exposed to the MAC layer for which one HARQ entity is
required per serving cell; [0090] In both uplink and downlink,
there is one independent hybrid-ARQ entity per serving cell and one
transport block is generated per TTI per serving cell in the
absence of spatial multiplexing. Each transport block and its
potential HARQ retransmissions are mapped to a single serving cell;
[0091] HARQ operation is asynchronous for Licensed-Assisted Access
(LAA) SCells. [0092] [FIGS. 6.4-1 of 3GPP R2-1809265, entitled
"Layer 2 Structure for DL with CA configured", is omitted] [0093]
[FIGS. 6.4-2 of 3GPP R2-1809265, entitled "Layer 2 Structure for UL
with CA configured", is omitted] In case of CA in sidelink, which
applies to V2X sidelink communication, there is one independent
HARQ entity per carrier used for V2X sidelink communication and one
transport block is generated per TTI per carrier. Each transport
block and its potential HARQ retransmissions are mapped to a single
carrier. [Figure 6.4-x of 3GPP R2-1809265, entitled "Layer 2
Structure for Sidelink with CA configured", is reproduced as FIG.
9] [ . . . ]
23.14.1.1 Support for V2X Sidelink Communication
[0094] The user plane protocol stack and functions, as specified in
subclause 23.10.2.1 for sidelink communication, are also used for
V2X sidelink communication. In addition, for V2X sidelink
communication: [0095] STCH for sidelink communication is also used
for V2X sidelink communication. [0096] Non-V2X (e.g. Public Safety)
data is not multiplexed with V2X data transmitted in resources
configured for V2X sidelink communication. [0097] The Access
Stratum (AS) is provided with the PPPP and PPPR of a protocol data
unit transmitted over PC5 interface by upper layers. The packet
delay budget (PDB) of the protocol data unit can be determined from
the PPPP. The low PDB is mapped to the high priority PPPP value
[72]. [0098] The Access Stratum (AS) is provided with a transmit
profile [72] of a protocol data unit transmitted over PC5 interface
by upper layers. [0099] The logical channel prioritization based on
PPPP is used for V2X sidelink communication. [ . . . ] UE
assistance information can be provided to eNB. Reporting of UE
assistance information is configured by eNB for V2X sidelink
communication. The UE assistance information used for V2X sidelink
communication includes traffic characteristic parameters (e.g. a
set of preferred SPS interval, timing offset with respect to
subframe 0 of the SFN 0, PPPP, PPPR, Destination Layer-2 ID, and
maximum TB size based on observed traffic pattern) related to the
SPS configuration. The UE assistance information can be reported in
case either SPS is already configured or not. Triggering of UE
assistance information transmission is left to UE implementation.
For instance, the UE is allowed to report UE assistance information
when change in estimated periodicity and/or timing offset of packet
arrival occurs. SR mask per traffic type is not supported for V2X
sidelink communication. [ . . . ] Carrier aggregation (CA) in
sidelink is supported for V2X sidelink communication. It applies to
both in coverage UEs and out of coverage UEs. For CA in sidelink,
neither primary component carrier nor secondary component carriers
are defined. Each resource pool (pre)configured for V2X sidelink
communication transmission or reception is associated to a single
carrier. When a UE supporting CA in sidelink uses autonomous
resource selection, it performs carrier selection and may select
one or more carriers used for V2X sidelink communication
transmission. The carrier selection is performed at MAC layer,
depending on the CBR of the (pre)configured carriers for V2X
sidelink communication and the PPPP(s) of the V2X messages to be
transmitted. The carrier reselection may be performed when resource
reselection is triggered and is triggered for each sidelink
process. In order to avoid frequent switching across different
carriers, the UE may keep using a carrier already selected for
transmission, if the measured CBR on this carrier is lower than a
(pre)configured threshold. For a UE using autonomous resource
selection, logical channel prioritization is performed for a
sidelink resource on a carrier depending on the CBR measured on the
carrier and the PPPP of the sidelink logical channels as specified
in 3GPP TS 36.321 [13]. Sidelink packet duplication is supported
for V2X sidelink communication and is performed at PDCP layer of
the UE. For sidelink packet duplication for transmission, a PDCP
PDU is duplicated at the PDCP entity. The duplicated PDCP PDUs of
the same PDCP entity are submitted to two different RLC entities
and associated to two different sidelink logical channels
respectively. The duplicated PDCP PDUs of the same PDCP entity are
only allowed to be transmitted on different sidelink carriers. A UE
can activate or deactivate sidelink packet duplication based on
(pre)configuration. The PPPR value(s) for which sidelink packet
duplication is supported can be (pre)configured via a PPPR
threshold. For UE autonomous resource selection and scheduled
resource allocation, the UE shall perform sidelink packet
duplication for the data with the configured PPPR value(s) until
packet duplication is deconfigured for these PPPR value(s). For
scheduled resource allocation, the UE reports the amount of data
associated with one or more PPPR values, and the destination(s) to
which the data belongs via sidelink BSR(s). A mapping of PPPR
values to logical channel groups can be configured by the eNB, and
the PPPR value(s) are reflected by the associated logical channel
group ID included in the sidelink BSR(s). A list of PPPR value(s)
may be reported in Sidelink UE information by an RRC_CONNECTED UE.
For a UE using scheduled resource allocation, two non-overlapped
sets of carriers are configured by the eNB per Destination reported
by the UE to the network, and they apply to all the PPPR(s) that
are configured for sidelink packet duplication. The UE then
associates two duplicated sidelink logical channels corresponding
to the same PDCP entity respectively with the two sets of carriers
configured for the Destination of the two sidelink logical
channels. The association between the duplicated sidelink logical
channel and the carrier set is up to UE implementation. Data of a
duplicated sidelink logical channel can only be transmitted on the
carrier(s) in the associated carrier set. For V2X sidelink
communication reception, packet duplication detection is performed
at PDCP layer of the UE. Reordering function is also supported at
PDCP layer and how to set the reordering timer at the PDCP layer is
up to UE implementation. There are specific logical channel
identities which apply to the sidelink logical channel used for
sidelink packet duplication exclusively as specified in 3GPP TS
36.321 [13].
[0100] 3GPP R2-1808916 introduces the following descriptions and
concepts:
6.2.4 MAC Header for SL-SCH
[0101] The MAC header is of variable size and consists of the
following fields: [0102] V: The MAC PDU format version number field
indicates which version of the SL-SCH subheader is used. In this
version of the specification three format versions are defined, and
this field shall therefore be set to "0001", "0010", and "0011". If
the DST field is 24 bits this field shall be set to "0011". The V
field size is 4 bits; [0103] SRC: The Source Layer-2 ID field
carries the identity of the source. It is set to the ProSe UE ID.
The SRC field size is 24 bits; [0104] DST: The DST field can be 16
bits or 24 bits. If it is 16 bits, it carries the 16 most
significant bits of the Destination Layer-2 ID. If it is 24 bits,
it is set to the Destination Layer-2 ID. For sidelink
communication, the Destination Layer-2 ID is set to the ProSe
Layer-2 Group ID or Prose UE ID. For V2X sidelink communication,
the Destination Layer-2 ID is set to the identifier provided by
upper layers as defined in [14]. If the V field is set to "0001",
this identifier is a groupcast identifier. If the V field is set to
"0010", this identifier is a unicast identifier; [0105] LCID: The
Logical Channel ID field uniquely identifies the logical channel
instance within the scope of one Source Layer-2 ID and Destination
Layer-2 ID pair of the corresponding MAC SDU or padding as
described in table 6.2.4-1. There is one LCID field for each MAC
SDU or padding included in the MAC PDU. In addition to that, one or
two additional LCID fields are included in the MAC PDU, when
single-byte or two-byte padding is required but cannot be achieved
by padding at the end of the MAC PDU. The values of LCID from
`01011` to `10100` identify the logical channels used to send
duplicated RLC SDUs from logical channels of which the values of
LCID from `00001` to `01010` respectively in sequential order. The
LCID field size is 5 bits; [0106] L: The Length field indicates the
length of the corresponding MAC SDU in bytes. There is one L field
per MAC PDU subheader except for the last subheader. The size of
the L field is indicated by the F field; [0107] F: The Format field
indicates the size of the Length field as indicated in table
6.2.4-2. There is one F field per MAC PDU subheader except for the
last subheader. The size of the F field is 1 bit. If the size of
the MAC SDU is less than 128 bytes, the value of the F field is set
to 0, otherwise it is set to 1; [0108] E: The Extension field is a
flag indicating if more fields are present in the MAC header or
not. The E field is set to "1" to indicate another set of at least
R/R/E/LCID fields. The E field is set to "0" to indicate that
either a MAC SDU or padding starts at the next byte; [0109] R:
Reserved bit, set to "0". The MAC header and subheaders are octet
aligned. [Table 6.2.4-1 of 3GPP R2-1808916, entitled "Values of
LCID for SL-SCH", is reproduced as FIG. 10] [0110] [Table 6.2.4-2
of 3GPP R2-1808916, entitled "Values of F field", is reproduced as
FIG. 11]
[0111] 3GPP R2-1808921 introduces the following descriptions and
concepts:
5.1.2.1.4 Procedures for DRBs Mapped on RLC AM, for LWA Bearers and
SLRB when the Reordering Function is Used For DRBs mapped on RLC AM
and for LWA bearers, the PDCP entity shall use the reordering
function as specified in this section when: [0112] the PDCP entity
is associated with two AM RLC entities; or [0113] the PDCP entity
is configured for a LWA bearer; or [0114] the PDCP entity is
associated with one AM RLC entity after it was, according to the
most recent reconfiguration, associated with two AM RLC entities or
configured for a LWA bearer without performing PDCP
re-establishment. For SLRBs mapped on RLC UM, the PDCP entity shall
use the reordering function as specified in this section when:
[0115] the PDCP entity is associated with two sidelink UM RLC
entities; The PDCP entity shall not use the reordering function in
other cases. 5.1.2.1.4.1 Procedures when a PDCP PDU is Received
from the Lower Layers For DRBs mapped on RLC AM, SLRB for
duplicated transmission and for LWA bearers, when the reordering
function is used, at reception of a PDCP Data PDU from lower
layers, the UE shall: [0116] if received PDCP
SN-Last_Submitted_PDCP_RX_SN>Reordering_Window or
0<=Last_Submitted_PDCP_RX_SN-received PDCP
SN<Reordering_Window: [0117] if the PDCP PDU was received on
WLAN: [0118] if received PDCP SN>Next_PDCP_RX_SN: [0119] for the
purpose of setting the HRW field in the LWA status report, use
COUNT based on RX_HFN-1 and the received PDCP SN; [0120] else:
[0121] for the purpose of setting the HRW field in the LWA status
report, use COUNT based on RX_HFN and the received PDCP SN; [0122]
discard the PDCP PDU; [0123] else if Next_PDCP_RX_SN-received PDCP
SN>Reordering_Window: [0124] increment RX_HFN by one; [0125] use
COUNT based on RX_HFN and the received PDCP SN for deciphering the
PDCP PDU; [0126] set Next_PDCP_RX_SN to the received PDCP SN+1;
[0127] else if received PDCP
SN-Next_PDCP_RX_SN>=Reordering_Window: [0128] use COUNT based on
RX_HFN-1 and the received PDCP SN for deciphering the PDCP PDU;
[0129] else if received PDCP SN>=Next_PDCP_RX_SN: [0130] use
COUNT based on RX_HFN and the received PDCP SN for deciphering the
PDCP PDU; [0131] set Next_PDCP_RX_SN to the received PDCP SN+1;
[0132] if Next_PDCP_RX_SN is larger than Maximum_PDCP_SN: [0133]
set Next_PDCP_RX_SN to 0; [0134] increment RX_HFN by one; [0135]
else if received PDCP SN<Next_PDCP_RX_SN: [0136] use COUNT based
on RX_HFN and the received PDCP SN for deciphering the PDCP PDU;
[0137] if the PDCP PDU has not been discarded in the above: [0138]
if a PDCP SDU with the same PDCP SN is stored: [0139] discard the
PDCP PDU; [0140] else: [0141] perform deciphering of the PDCP PDU
and store the resulting PDCP SDU; [0142] if received PDCP
SN=Last_Submitted_PDCP_RX_SN+1 or received PDCP
SN=Last_Submitted_PDCP_RX_SN-Maximum_PDCP_SN: [0143] deliver to
upper layers in ascending order of the associated COUNT value:
[0144] all stored PDCP SDU(s) with consecutively associated COUNT
value(s) starting from the COUNT value associated with the received
PDCP PDU; [0145] set Last_Submitted_PDCP_RX_SN to the PDCP SN of
the last PDCP SDU delivered to upper layers; [0146] if t-Reordering
is running: [0147] if the PDCP SDU with Reordering_PDCP_RX_COUNT-1
has been delivered to upper layers: [0148] stop and reset
t-Reordering; [0149] if t-Reordering is not running (includes the
case when t-Reordering is stopped due to actions above): [0150] if
there is at least one stored PDCP SDU: [0151] start t-Reordering;
[0152] set Reordering_PDCP_RX_COUNT to the COUNT value associated
to RX_HFN and Next_PDCP_RX_SN. [ . . . ]
5.1.3 SL Data Transmission Procedures
[0153] For Sidelink transmission, the UE shall follow the
procedures in subclause 5.1.1 with following modifications: [0154]
the requirements for maintaining Next_PDCP_TX_SN and TX_HFN are not
applicable; [0155] determine a PDCP SN ensuring that a PDCP SN
value is not reused with the same key; [0156] perform ciphering (if
configured) as specified in subclause 5.6.1 and 5.6.2; [0157]
perform the header compression (if configured) if SDU Type is set
to 000, i.e. IP SDUs. For sidelink duplication transmission capable
UE, when PDCP duplication transmission is configured, for the SLRB
with packets which have PPPR no lower than the configured PPPR
threshold, the Sidelink transmission of UE shall follow the
procedures in subclause 5.1.1 with following modifications compared
to above Sidelink transmission procedure: [0158] the requirements
for maintaining Next_PDCP_TX_SN and TX_HFN are applicable; [0159]
the PDCP entity duplicates the PDCP PDUs, and delivers the PDCP
PDUs to both RLC entities for transmission.
5.1.4 SL Data Reception Procedures
[0160] For Sidelink reception, the UE shall follow the procedures
in subclause 5.1.2.1.3 with following modifications: [0161] the
requirements for maintaining Next_PDCP_RX_SN and RX_HFN are not
applicable; [0162] perform the deciphering (if configured) as
specified in subclause 5.6.1 and 5.6.2; [0163] perform the header
decompression (if configured) if SDU Type is set to 000, i.e. IP
SDUs. For sidelink duplication reception capable UE, if it detects
PDCP duplication reception in duplication logical channel, or if it
receives a PDCP SN which is not "0" from the non-duplication
logical channel, the Sidelink reception of the UE shall follow the
procedures in subclause 5.1.2.1.4.1 with following modifications
compared to above Sidelink reception procedure: [0164] the
requirements for maintaining Next_PDCP_RX_SN and RX_HFN are
applicable; [0165] perform the re-ordering procedure as specified
in subclause 5.1.2.1.4.1. [ . . . ]
5.6.1 SL Ciphering and Deciphering for One-To-Many
Communication
[0166] For SLRB used for one-to-many communication, the ciphering
function includes both ciphering and deciphering and is performed
in PDCP as defined in [13]. The data unit that is ciphered is the
data part of the PDCP PDU (see subclause 6.3.3). The ciphering
function as specified in [6] is applied with KEY (PEK), COUNT
(derived from PTK Identity and PDCP SN as specified in [13]),
BEARER and DIRECTION (set to 0) as input. The ciphering function is
configured by ProSe Function. If ciphering is configured, the
ciphering algorithm and related parameters including PGK, PGK
Identity, and Group Member Identity are configured to the UE by
ProSe Key Management Function. The UE shall set PTK Identity based
on PGK, PGK Identity, and PDCP SN as specified in [13]. The UE
shall derive PTK from PGK using PTK Identity and Group Member
Identity, and derive PEK from PTK using the ciphering algorithm.
The PGK Index, PTK Identity, and PDCP SN are included in the PDCP
PDU header. If ciphering is not configured, PGK Index and PTK
Identity shall be set to "0" in the PDCP PDU header. If ciphering
is not configured, and sidelink duplication transmission is
disabled for the SLRB, PDCP SN shall be set to "0" in the PDCP PDU
header.
5.6.2 SL Ciphering and Deciphering for One-To-One Communication
[0167] For SLRB used for one-to-one communication, the ciphering
function includes both ciphering and deciphering and is performed
in PDCP of SLRB that needs ciphering and deciphering as defined in
[13]. The data unit that is ciphered is the data part of the PDCP
PDU (see subclause 6.3.3). The ciphering function as specified in
[6] is applied with KEY (PEK), COUNT (derived from K.sub.D-sess
Identity and PDCP SN as specified in [13]), BEARER and DIRECTION
(which value shall be set is specified in [13]) as input. For the
SLRB that needs ciphering and deciphering, the UE shall derive the
KEY (PEK) based on K.sub.D-sess and the algorithms determined by
the initiating UE and the receiving UE as specified in [13]. The
K.sub.D-sess Identity and PDCP SN are included in the PDCP PDU
header. For the SLRB that does not need ciphering and deciphering,
the UE shall set K.sub.D-sess Identity to "0" in the PDCP PDU
header. For the SLRB that does not need ciphering and deciphering,
and sidelink duplication transmission is disabled, PDCP SN shall be
set "0" in the PDCP PDU header. [ . . . ] b) t-Reordering The
duration of the timer is configured by upper layers [3] except for
the case of SL PDCP duplication reception. For SL PDCP duplication
transmission, the t-Reordering timer is generated by the UE. This
timer is used to detect loss of PDCP PDUs as specified in the
subclause 5.1.2.1.4. If t-Reordering is running, t-Reordering shall
not be started additionally, i.e. only one t-Reordering per PDCP
entity is running at a given time. According to 3GPP R2-1809265,
carrier aggregation (CA) in sidelink is supported for V2X
(Vehicle-to-Everything) sidelink communication. It applies to both
in coverage UEs and out of coverage UEs. In addition, sidelink
packet duplication will be supported for V2X sidelink communication
and may be performed at PDCP (Packet Data Convergence Protocol)
layer of the UE. For sidelink packet duplication for transmission,
a PDCP PDU (Protocol Data Unit) is duplicated at the PDCP entity.
The duplicated PDCP PDUs of the same PDCP entity are submitted or
delivered to two different RLC (Radio Link Control) entities and
associated with two different sidelink logical channels
respectively. The duplicated PDCP PDUs of the same PDCP entity are
only allowed to be transmitted on different sidelink carriers. A UE
can activate or deactivate sidelink packet duplication based on
(pre)configuration. The PPPR (ProSe Per-Packet Reliability)
value(s) for which sidelink packet duplication is supported can be
(pre)configured via a PPPR threshold.
[0168] For UE autonomous resource selection and scheduled resource
allocation, the UE shall perform sidelink packet duplication for
the data with the configured PPPR value(s) until packet duplication
is de-configured for these PPPR value(s). For scheduled resource
allocation, the UE reports the amount of data associated with one
or more PPPR values, and the destination(s) to which the data
belongs via sidelink BSR(s) (Buffer Status Report). A mapping of
PPPR values to logical channel groups can be configured by the eNB,
and the PPPR value(s) are reflected by the associated logical
channel group ID included in the sidelink BSR(s). A list of PPPR
value(s) may be reported in Sidelink UE information by an
RRC_CONNECTED UE.
[0169] For a UE using scheduled resource allocation, two
non-overlapped sets of carriers are configured by the eNB per
Destination reported by the UE to the network, and they apply to
all the PPPR(s) that are configured for sidelink packet
duplication. The UE then associates two duplicated sidelink logical
channels corresponding to the same PDCP entity respectively with
the two sets of carriers configured for the Destination of the two
sidelink logical channels. The Destination could be an identity
corresponding to one or more than one (receiving) UEs to which the
(transmitting) UE perform sidelink communication transmission. The
association between the duplicated sidelink logical channel and the
carrier set is up to UE implementation. Data of a duplicated
sidelink logical channel can only be transmitted on the carrier(s)
in the associated carrier set.
[0170] FIG. 12 illustrates an example of transmission operation for
sidelink packet duplication. A (transmitting) UE may have data
available for transmission (for a destination) on a sidelink radio
bearer (SLRB). The SLRB could be associated with a reliability
(e.g. PPPR). The reliability may be lower than a threshold. The UE
may perform sidelink packet duplication on the SLRB. The UE could
duplicate a PDCP PDU. The UE could deliver the PDCP PDU and the
duplicate of the PDCP PDU into two different RLC entities/layers
associated with the SLRB. The UE could also deliver the PDCP PDU
into a first RLC entity/layer associated with the SLRB. In
addition, the UE could deliver the duplicate of the PDCP PDU into a
second RLC entity/layer associated with the SLRB. The UE may be
configured with sidelink packet duplication on the SLRB. The UE
could maintain parameter(s) used for sidelink transmission on the
SLRB. The parameter could be Next_PDCP_TX_SN. The parameter could
be TX_HFN.
[0171] For the sidelink packet duplication, the UE may select a
non-duplication logical channel from a first range (e.g. LCH1 to
LCH10, `00001` to `01010`, or etc). For the sidelink packet
duplication, the UE may select a duplication logical channel from a
second range (e.g. LCH11 to LCH20, `01011` to `10100`, or etc). The
values of the first range may identify the logical channels used to
send duplicated RLC (Radio Link Control) SDUs (Service Data Units)
from logical channels of which the values of the second range
respectively in sequential order. In this example, the UE may use a
first logical channel (e.g. LCH1) and a second logical channel
(e.g. LCH11) for the sidelink packet duplication. The UE may use a
first carrier (e.g. Carrier 1) to serve the first logical channel.
The UE may also use a second carrier (e.g. Carrier 2) to serve the
second logical channel.
[0172] FIG. 13 illustrates an example of reception operation for
sidelink packet duplication. According to 3GPP R2-1808921, a
(sidelink duplication reception capable) UE could detect PDCP
duplication reception based on receiving traffic on duplication
logical channel or receiving traffic associated with a PDCP SN
which is not "0" from non-duplication logical channel. The traffic
could be a PDCP PDU or a PDCP SDU. The UE may use a first carrier
(e.g. Carrier 1) to serve the non-duplication logical channel. The
UE may also use a second carrier (e.g. Carrier 2) to serve the
duplication logical channel.
[0173] For an example, the UE may (first) receive a first traffic
on a first logical channel (e.g. LCH1). The first traffic may be
associated with a PDCP SN="1". In this situation, the UE could
understand or determine to associate the first logical channel with
a SLRB on which sidelink packet duplication will be performed. The
UE may receive a first traffic on a second logical channel (e.g.
LCH11). In this situation, the UE could understand or determine to
associate the second logical channel with the SLRB and/or with the
first logical channel (based on e.g. LCID pair). The content of the
first traffic on the first logical channel may be the same as the
content of the first traffic on the second logical channel. The
first traffic on the second logical channel could be the duplicate
of the first traffic on the first logical channel.
[0174] For another example, the (receiving) UE may (first) receive
a second traffic on the second logical channel. In this situation,
the UE could understand or determine to associate the second
logical channel with a SLRB on which sidelink packet duplication
will be performed. The UE may receive a second traffic on the first
second logical channel. In this situation, the UE could understand
or determine to associate the first logical channel with the SLRB
and/or to associate the first logical channel with the second
logical channel (based on e.g. LCID pair). The content of the
second traffic on the first logical channel may be the same as the
content of the second traffic on the second logical channel. The
second traffic on the second logical channel could be the duplicate
of the second traffic on the first logical channel.
[0175] The UE could maintain parameter(s) used for sidelink
reception on the SLRB (if PDCP duplication reception is detected).
The parameter could be Next_PDCP_RX_SN. The parameter could be
RX_HFN. The UE could perform re-ordering procedure for the sidelink
reception on the SLRB (if PDCP duplication reception is
detected).
[0176] In one embodiment, the UE may first receive a PDCP PDU with
SN=0 on the first logical channel. Based on 3GPP R2-1808921, the UE
would deliver the resulting PDCP SDU of this PDCP PDU to upper
layer but not maintain the parameter(s) (e.g. Next_PDCP_RX_SN
and/or RX_HFN) used for sidelink reception on the SLRB. This could
be because that (i) the UE could not understand (or determine or
know) the PDCP PDU with SN=0 received on the first logical channel
is a duplicate of the PDCP PDU, or (ii) the PDCP PDU with SN=0
received from the first logical channel is neither a PDCP PDU with
SN not equal to non-zero nor a PDCP PDU received from the
duplication logical channel. The UE could not store resulting PDCP
SDU of the PDCP PDU with SN=0 received on the first logical
channel.
[0177] When UE receives a PDCP PDU with SN=0 on the second logical
channel, the UE could understand (or determine or know) the PDCP
PDU received on the second logical channel is a duplicate of the
PDCP PDU (with SN=0) received on the first logical channel, and
would maintain the parameter(s) used for the sidelink reception on
the SLRB. In this situation, the UE would deliver a resulting PDCP
SDU of the duplicate of the PDCP PDU to the upper layer because
there is no stored resulting PDCP SDU of the duplicate for the SLRB
based on the (current) maintained parameter(s).
[0178] For example, the UE could not maintain Next_PDCP_RX_SN
and/or RX_HFN on the SLRB when the PDCP PDU with SN=0 is received
on the first logical channel. The UE could deliver a PDCP SDU of
the PDCP PDU with SN=0 received on the first logical channel to
upper layer. The UE could not store the PDCP SDU of the PDCP PDU
with SN=0 received on the first logical channel. When the PDCP PDU
with SN=0 is received on the second logical channel, the UE could
(start to) maintain Next_PDCP_RX_SN and/or RX_HFN on the SLRB. The
Next_PDCP_RX_SN could be `0`. The RX_HFN could be `0`. Since the SN
(=`0`) of the PDCP PDU received on the second logical channel
equals to the Next_PDCP_RX_SN (=`0`), the UE could consider there
is no stored PDCP SDU of the PDCP PDU received on the second
logical channel. The UE could store a PDCP SDU of the PDCP PDU
received on the second logical channel. The UE could deliver a PDCP
SDU of the PDCP PDU received on the second logical channel to the
upper layer. Actually, the PDCP SDU of the PDCP PDU with SN=0
received on the first logical channel has been delivered to upper
layers, and delivery of the PDCP SDU of the PDCP PDU with SN=0
received on the second logical channel seems not needed. The issue
could be illustrated in FIGS. 14 and 15.
[0179] Since the sidelink packet duplication could be used for V2X
sidelink communication, this situation would cause unexpected UE
behaviour for receiving duplicates of the same V2X service
information in view of upper layers (e.g. V2X applications). To
avoid the penalties, some alternative may be addressed.
[0180] In one alternative, a SN of a (very first) PDCP SDU for
transmission with sidelink packet duplication may be started from a
specific number. The specific number could be larger than `0` (or
could not be `0`). For example, the specific number could be `1`.
The SN could be a PDCP SN.
[0181] In one embodiment, the (transmitting) UE could transmit the
(very first) PDCP SDU with SN started from `1`. The (transmitting)
UE could increment Next_PDCP_TX_SN by one (or by a number which is
larger than `0`) before associating the SN corresponding to the
Next_PDCP_TX_SN to the (very first) PDCP SDU. The (transmitting) UE
could also set Next_PDCP_TX_SN to non-zero (e.g. a number which is
larger than `0`) when a PDCP entity for the SLRB is
established.
TABLE-US-00001 Text proposal on top of [5] for TS38.323 - Example
1-1 5.1.3 SL Data Transmission Procedures For Sidelink
transmission, the UE shall follow the procedures in subclause 5.1.1
with following modifications: the requirements for maintaining
Next_PDCP_TX_SN and TX_HFN are not applicable; determine a PDCP SN
ensuring that a PDCP SN value is not reused with the same key;
perform ciphering (if configured) as specified in subclause 5.6.1
and 5.6.2; perform the header compression (if configured) if SDU
Type is set to 000, i.e. IP SDUs. For sidelink duplication
transmission capable UE, when PDCP duplication transmission is
configured, for the SLRB with packets which have PPPR no lower than
the configured PPPR threshold, the Sidelink transmission of UE
shall follow the procedures in subclause 5.1.1 with following
modifications compared to above Sidelink transmission procedure:
the requirements for maintaining Next_PDCP_TX_SN and TX_HFN are
applicable; the Next_PDCP_TX_SN is initially set to 1; the PDCP
entity duplicates the PDCP PDUs, and delivers the PDCP PDUs to both
RLC entities for transmission.
TABLE-US-00002 Text proposal on top of [5] for TS38.323 - Example
1-2 5.1.1 UL Data Transfer Procedures At reception of a PDCP SDU
from upper layers, the UE shall: start the discardTimer associated
with this PDCP SDU (if configured); For a PDCP SDU received from
upper layers, the UE shall: if the PDCP SDU is received on the SLRB
configured with PDCP duplication transmission and the SLRB with
packets which have PPPR no lower than the configured PPPR threshold
and the PDCP SDU is the very first PDCP SDU for this SLRB:
increment Next_PDCP_TX_SN by one; associate the PDCP SN
corresponding to Next_PDCP_TX_SN to this PDCP SDU; NOTE:
Associating more than half of the PDCP SN space of contiguous PDCP
SDUs with PDCP SNs, when e.g., the PDCP SDUs are discarded or
transmitted without acknowledgement, may cause HFN
desynchronization problem. How to prevent HFN desynchronization
problem is left up to UE implementation. perform header compression
of the PDCP SDU (if configured) as specified in the subclause
5.5.4; perform integrity protection (if applicable), and ciphering
(if applicable) using COUNT based on TX_HFN and the PDCP SN
associated with this PDCP SDU as specified in the subclause 5.7 and
5.6, respectively; increment Next_PDCP_TX_SN by one; if
Next_PDCP_TX_SN > Maximum_PDCP_SN: set Next_PDCP_TX_SN to 0;
increment TX_HFN by one; submit the resulting PDCP Data PDU to
lower layer.
TABLE-US-00003 Text proposal on top of [5] for TS38.323 - Example
1-3 7.1 State variables This sub clause describes the state
variables used in PDCP entities in order to specify the PDCP
protocol. All state variables are non-negative integers. The
transmitting side of each PDCP entity shall maintain the following
state variables: a) Next_PDCP_TX_SN The variable Next_PDCP_TX_SN
indicates the PDCP SN of the next PDCP SDU for a given PDCP entity.
At establishment of the PDCP entity, the UE shall set
Next_PDCP_TX_SN to 0. For sidelink duplication transmission capable
UE, when PDCP duplication transmission is configured, for the SLRB
with packets which have PPPR no lower than the configured PPPR
threshold, the UE shall initially set Next_PDCP_TX_SN to 1.
[0182] In another alternative, the (receiving) UE could not deliver
a PDCP SDU of a PDCP PDU with SN=0 received on a second logical
channel to upper layer if a PDCP PDU with SN=0 has been received on
a first logical channel. The first logical channel could be a
non-duplication logical channel. The second logical channel could
be a duplication logical channel. The duplication logical channel
could be associated with the non-duplication logical channel. The
PDCP PDU with SN=0 received on the first logical channel could be a
very first PDCP PDU with SN=0 received on the first logical
channel. The PDCP PDU with SN=0 received on the second logical
channel could be a very first PDCP PDU with SN=0 received on the
second logical channel. However, the very first PDCP PDU with SN=0
received on the second logical channel could be a PDCP PDU with
SN=0 for which the SN could wrap around. If the UE follows this
principle, the UE could not deliver the very first PDCP PDU with
SN=0 received on the second logical channel. This situation could
be illustrated in FIG. 16.
[0183] In one embodiment, the UE could not maintain parameter(s)
used for sidelink reception after receiving the PDCP PDU with SN=0
on the first logical channel. For example, the UE could not set the
parameter(s) used for sidelink reception to `0` before receiving
the PDCP PDU with SN=0 on the first logical channel. Furthermore,
the UE could not set the parameter(s) used for sidelink reception
based on the SN of the PDCP PDU after receiving the PDCP PDU with
SN=0 on the first logical channel.
[0184] In one embodiment, the UE could store a PDCP SDU of the PDCP
PDU with SN=0 received on the first logical channel after receiving
this PDCP PDU on the first logical channel. The UE could deliver
the PDCP SDU with SN=0 received on the first logical channel to
upper layer.
[0185] In one embodiment, the UE could not maintain parameter(s)
used for sidelink reception upon reception of the PDCP PDU with
SN=0 on the first logical channel. For example, the UE could not
set the parameter(s) used for sidelink reception based on the SN of
the PDCP PDU upon reception of the PDCP PDU with SN=0 on the first
logical channel.
[0186] In one embodiment, the UE could store a PDCP SDU of the PDCP
PDU with SN=0 received on the first logical channel upon reception
of this PDCP PDU on the first logical channel. The UE could deliver
the PDCP SDU with SN=0 received on the first logical channel to
upper layer.
[0187] In one embodiment, the UE could not maintain parameter(s)
used for sidelink reception when the PDCP PDU with SN=0 is received
on the first logical channel. For example, the UE could not set the
parameter(s) used for sidelink reception based on the SN of the
PDCP PDU when the PDCP PDU with SN=0 is received on the first
logical channel.
[0188] In one embodiment, the UE could store a PDCP SDU of the PDCP
PDU with SN=0 received on the first logical channel when this PDCP
PDU is received on the first logical channel. The UE could deliver
the PDCP SDU with SN=0 received on the first logical channel to
upper layer.
[0189] In one embodiment, the UE could not maintain parameter(s)
used for sidelink reception before receiving the PDCP PDU with SN=0
on the second logical channel. For example, the UE could not set
the parameter(s) used for sidelink reception based on the SN of the
PDCP PDU before receiving the PDCP PDU with SN=0 on the second
logical channel.
[0190] In one embodiment, the UE could maintain parameter(s) used
for sidelink reception after receiving the PDCP PDU with SN=0 on
the second logical channel. For example, the UE could set the
parameter(s) used for sidelink reception based on the SN of the
PDCP PDU after receiving the PDCP PDU with SN=0 on the second
logical channel.
[0191] In one embodiment, the UE could not store a PDCP SDU of the
PDCP PDU with SN=0 received on the second logical channel after
receiving this PDCP PDU on the second logical channel. The UE could
discard the PDCP SDU with SN=0 received on the second logical
channel (before the parameter(s) used for sidelink reception could
wrap around) if no PDCP SDU except for the PDCP SDU with SN=0 has
been received on the first logical channel (and/or the second
logical channel) or delivered to upper layer (before the
parameter(s) used for sidelink reception could wrap around). The UE
could also discard a PDCP PDU containing the PDCP SDU with SN=0
received on the second logical channel (before the parameter(s)
used for sidelink reception could wrap around) if no PDCP PDU
except for a PDCP PDU with SN=0 has been received on the first
logical channel (and/or the second logical channel) (before the
parameter(s) used for sidelink reception could wrap around). In
addition, the UE could discard the PDCP SDU with SN=0 received on
the second logical channel if this PDCP SDU is a very first PDCP
SDU with SN=0 received on the second logical channel (before the
parameter(s) used for sidelink reception could wrap around) and a
PDCP SDU with SN=0 received on the first logical channel has been
delivered to upper layer (before the parameter(s) used for sidelink
reception could wrap around). Furthermore, the UE could discard the
PDCP PDU with SN=0 received on the second logical channel if this
PDCP PDU is a very first PDCP PDU with SN=0 received on the second
logical channel (before the parameter(s) used for sidelink
reception could wrap around) and a PDCP PDU with SN=0 has been
received on the first logical channel (before the parameter(s) used
for sidelink reception could wrap around).
[0192] In one embodiment, the UE could maintain parameter(s) used
for sidelink reception upon reception of the PDCP PDU with SN=0 on
the second logical channel. For example, the UE could set the
parameter(s) used for sidelink reception based on the SN of the
PDCP PDU upon reception of the PDCP PDU with SN=0 on the second
logical channel.
[0193] In one embodiment, the UE could not store a PDCP SDU of the
PDCP PDU with SN=0 received on the second logical channel upon
reception of this PDCP PDU on the second logical channel. The UE
could discard the PDCP SDU with SN=0 received on the second logical
channel (before the parameter(s) used for sidelink reception could
wrap around) if no PDCP SDU except for the PDCP SDU with SN=0 has
been received on the first logical channel (and/or the second
logical channel) or delivered to upper layer (before the
parameter(s) used for sidelink reception could wrap around). The UE
could also discard a PDCP PDU containing the PDCP SDU with SN=0
received on the second logical channel (before the parameter(s)
used for sidelink reception could wrap around) if no PDCP PDU
except for a PDCP PDU with SN=0 has been received on the first
logical channel (and/or the second logical channel) (before the
parameter(s) used for sidelink reception could wrap around).
Furthermore, the UE could discard the PDCP SDU with SN=0 received
on the second logical channel if this PDCP SDU is a very first PDCP
SDU with SN=0 received on the second logical channel (before the
parameter(s) used for sidelink reception could wrap around) and a
PDCP SDU with SN=0 received on the first logical channel has been
delivered to upper layer (before the parameter(s) used for sidelink
reception could wrap around). In addition, the UE could discard the
PDCP PDU with SN=0 received on the second logical channel if this
PDCP PDU is a very first PDCP PDU with SN=0 received on the second
logical channel (before the parameter(s) used for sidelink
reception could wrap around) and a PDCP PDU with SN=0 has been
received on the first logical channel (before the parameter(s) used
for sidelink reception could wrap around).
[0194] In one embodiment, the parameter(s) used for sidelink
reception could be Next_PDCP_RX_SN or RX_HFN.
[0195] In another alternative, the (receiving) UE could not deliver
a PDCP SDU with SN=0 received on a second logical channel to upper
layer if a PDCP SDU with SN=0 has been received on a first logical
channel. The first logical channel could be a non-duplication
logical channel. The second logical channel could be a duplication
logical channel. The duplication logical channel could be
associated with the non-duplication logical channel. The PDCP SDU
with SN=0 received on the first logical channel could be a very
first PDCP SDU with SN=0 received on the first logical channel. The
PDCP SDU with SN=0 received on the second logical channel could be
a very first PDCP SDU with SN=0 received on the second logical
channel. However, the very first PDCP PDU with SN=0 received on the
second logical channel could be a PDCP PDU with SN=0 for which the
SN could wrap around. If the UE follows this principle, the UE
could not deliver the very first PDCP PDU with SN=0 received on the
second logical channel. This situation could be illustrated in FIG.
16.
[0196] In one embodiment, the UE could not maintain parameter(s)
used for sidelink reception after receiving the PDCP SDU with SN=0
on the first logical channel. For example, the UE could not set the
parameter(s) used for sidelink reception based on the SN of the
PDCP SDU after receiving the PDCP SDU with SN=0 on the first
logical channel.
[0197] In one embodiment, the UE could store the PDCP SDU with SN=0
received on the first logical channel after receiving this PDCP SDU
on the first logical channel. The UE could deliver the PDCP SDU
with SN=0 received on the first logical channel to upper layer.
[0198] In one embodiment, the UE could not maintain parameter(s)
used for sidelink reception upon reception of the PDCP SDU with
SN=0 on the first logical channel. For example, the UE could not
set the parameter(s) used for sidelink reception based on the SN of
the PDCP SDU upon reception of the PDCP SDU with SN=0 on the first
logical channel.
[0199] In one embodiment, the UE could store the PDCP SDU with SN=0
received on the first logical channel upon reception of this PDCP
SDU on the first logical channel. The UE could deliver the PDCP SDU
with SN=0 received on the first logical channel to upper layer.
[0200] In one embodiment, the UE could not maintain parameter(s)
used for sidelink reception before receiving the PDCP SDU with SN=0
on the second logical channel. For example, the UE could not set
the parameter(s) used for sidelink reception based on the SN of the
PDCP SDU before receiving the PDCP SDU with SN=0 on the second
logical channel.
[0201] In one embodiment, the UE could maintain parameter(s) used
for sidelink reception after receiving the PDCP SDU with SN=0 on
the second logical channel. For example, the UE could set the
parameter(s) used for sidelink reception based on the SN of the
PDCP SDU after receiving the PDCP SDU with SN=0 on the second
logical channel.
[0202] In one embodiment, the UE could not store the PDCP SDU with
SN=0 received on the second logical channel after receiving this
PDCP SDU on the second logical channel. The UE could discard the
PDCP SDU with SN=0 received on the second logical channel (before
the parameter(s) used for sidelink reception could wrap around) if
no PDCP SDU except for the PDCP SDU with SN=0 has been received on
the first logical channel (and/or the second logical channel) or
delivered to upper layer (before the parameter(s) used for sidelink
reception could wrap around). The UE could also discard a PDCP PDU
containing the PDCP SDU with SN=0 received on the second logical
channel (before the parameter(s) used for sidelink reception could
wrap around) if no PDCP PDU except for a PDCP PDU with SN=0 has
been received on the first logical channel (and/or the second
logical channel) (before the parameter(s) used for sidelink
reception could wrap around). Furthermore, the UE could discard the
PDCP SDU with SN=0 received on the second logical channel if this
PDCP SDU is a very first PDCP SDU with SN=0 received on the second
logical channel (before the parameter(s) used for sidelink
reception could wrap around) and a PDCP SDU with SN=0 received on
the first logical channel has been delivered to upper layer (before
the parameter(s) used for sidelink reception could wrap around). In
addition, the UE could discard the PDCP PDU with SN=0 received on
the second logical channel if this PDCP PDU is a very first PDCP
PDU with SN=0 received on the second logical channel (before the
parameter(s) used for sidelink reception could wrap around) and a
PDCP PDU with SN=0 has been received on the first logical channel
(before the parameter(s) used for sidelink reception could wrap
around).
[0203] In one embodiment, the UE could maintain parameter(s) used
for sidelink reception upon reception of the PDCP SDU with SN=0 on
the second logical channel. For example, the UE could set the
parameter(s) used for sidelink reception based on the SN of the
PDCP SDU upon reception of the PDCP SDU with SN=0 on the second
logical channel.
[0204] In one embodiment, the UE could not store the PDCP SDU with
SN=0 received on the second logical channel upon reception of this
PDCP SDU on the second logical channel. The UE could discard the
PDCP SDU with SN=0 received on the second logical channel (before
the parameter(s) used for sidelink reception could wrap around) if
no PDCP SDU except for the PDCP SDU with SN=0 has been received on
the first logical channel (and/or the second logical channel) or
delivered to upper layer (before the parameter(s) used for sidelink
reception could wrap around). The UE could also discard a PDCP PDU
containing the PDCP SDU with SN=0 received on the second logical
channel (before the parameter(s) used for sidelink reception could
wrap around) if no PDCP PDU except for a PDCP PDU with SN=0 has
been received on the first logical channel (and/or the second
logical channel) (before the parameter(s) used for sidelink
reception could wrap around). Furthermore, the UE could discard the
PDCP SDU with SN=0 received on the second logical channel if this
PDCP SDU is a very first PDCP SDU with SN=0 received on the second
logical channel (before the parameter(s) used for sidelink
reception could wrap around) and a PDCP SDU with SN=0 received on
the first logical channel has been delivered to upper layer (before
the parameter(s) used for sidelink reception could wrap around). In
addition, the UE could discard the PDCP PDU with SN=0 received on
the second logical channel if this PDCP PDU is a very first PDCP
PDU with SN=0 received on the second logical channel (before the
parameter(s) used for sidelink reception could wrap around) and a
PDCP PDU with SN=0 has been received on the first logical channel
(before the parameter(s) used for sidelink reception could wrap
around).
[0205] In one embodiment, the parameter(s) used for sidelink
reception could be Next_PDCP_RX_SN, RX_HFN,
Last_Submitted_PDCP_RX_SN, or COUNT.
[0206] In one embodiment, the parameter(s) used for sidelink
reception could be a window used to determine if it is first time
to receive a PDCP SDU with SN=0 within the window. For example, the
UE could receive a PDCP SDU with SN=0 on the first logical channel
within a first window. The UE could receive a PDCP SDU with SN=0 on
the second logical channel. If the PDCP SDU with SN=0 is received
on the second logical channel within the first window, the UE could
discard this PDCP SDU (and not deliver this PDCP SDU to upper
layer). If the PDCP SDU with SN=0 is received on the second logical
channel within a second window, the UE could not discard this PDCP
SDU (and deliver this PDCP SDU to upper layer). The first window
could be followed by the second window. The size/length of the
first/second window could be based on the size of PDCP SN, e.g. the
half size of PDCP SN. The size/length of the first/second window
could also be based on Reordering_Window. The parameter(s) used for
sidelink reception warping around could mean changing from the
first window to the second window. This solution could be
illustrated in FIG. 17.
[0207] In one embodiment, the parameter(s) used for sidelink
reception warping around could mean that the parameter(s) used for
sidelink reception's value of 2.sup.X-1 (i.e. 2{circumflex over (
)}X-1) could be less than the parameter(s) used for sidelink
reception's value of `0`, where X could be the size/length of the
parameter(s) used for sidelink reception.
TABLE-US-00004 Text proposal on top of [5] for TS38.323 - Example
2-1 5.1.2.1.4.1 Procedures when a PDCP PDU is received from the
lower layers For DRBs mapped on RLC AM, SLRB for duplicated
transmission and for LWA bearers, when the reordering function is
used, at reception of a PDCP Data PDU from lower layers, the UE
shall: . . . else if received PDCP SN >= Next_PDCP_RX_SN: use
COUNT based on RX_HFN and the received PDCP SN for deciphering the
PDCP PDU; set Next_PDCP_RX_SN to the received PDCP SN + 1; if
Next_PDCP_RX_SN is larger than Maximum_PDCP_SN: set Next_PDCP_RX_SN
to 0; increment RX_HFN by one; . . . if the PDCP PDU has not been
discarded in the above: if the PDCP PDU with SN = 0 is received on
the duplication logical channel and no PDCP SDU except for the PDCP
SDU with SN = 0 received on the associated non- duplication logical
channel has been delivered to upper layers: discard the PDCP PDU;
if a PDCP SDU with the same PDCP SN is stored: discard the PDCP
PDU; else: perform deciphering of the PDCP PDU and store the
resulting PDCP SDU; if received PDCP SN = Last_Submitted_PDCP_RX_SN
+ 1 or received PDCP SN = Last_Submitted_PDCP_RX_SN -
Maximum_PDCP_SN: deliver to upper layers in ascending order of the
associated COUNT value: all stored PDCP SDU(s) with consecutively
associated COUNT value(s) starting from the COUNT value associated
with the received PDCP PDU; set Last_Submitted_PDCP_RX_SN to the
PDCP SN of the last PDCP SDU delivered to upper layers;
TABLE-US-00005 Text proposal on top of [5] for TS38.323 - Example
2-2 5.1.2.1.4.1 Procedures when a PDCP PDU is received from the
lower layers For DRBs mapped on RLC AM, SLRB for duplicated
transmission and for LWA bearers, when the reordering function is
used, at reception of a PDCP Data PDU from lower layers, the UE
shall: . . . else if received PDCP SN >= Next_PDCP_RX_SN: use
COUNT based on RX_HFN and the received PDCP SN for deciphering the
PDCP PDU; set Next_PDCP_RX_SN to the received PDCP SN + 1; if
Next_PDCP_RX_SN is larger than Maximum_PDCP_SN: set Next_PDCP_RX_SN
to 0; increment RX_HFN by one; . . . if the PDCP PDU has not been
discarded in the above: if a PDCP SDU with the same PDCP SN is
stored; or if the PDCP PDU with SN = 0 is received on the
duplication logical channel and no PDCP SDU except for the PDCP SDU
with SN = 0 received on the associated non- duplication logical
channel has been delivered to upper layers: discard the PDCP PDU;
else: perform deciphering of the PDCP PDU and store the resulting
PDCP SDU; if received PDCP SN = Last_Submitted_PDCP_RX_SN + 1 or
received PDCP SN = Last_Submitted_PDCP_RX_SN - Maximum_PDCP_SN:
deliver to upper layers in ascending order of the associated COUNT
value: all stored PDCP SDU(s) with consecutively associated COUNT
value(s) starting from the COUNT value associated with the received
PDCP PDU; set Last_Submitted_PDCP_RX_SN to the PDCP SN of the last
PDCP SDU delivered to upper layers;
TABLE-US-00006 Text proposal on top of [5] for TS38.323 - Example
2-3 5.1.2.1.4.1 Procedures when a PDCP PDU is received from the
lower layers For DRBs mapped on RLC AM, SLRB for duplicated
transmission and for LWA bearers, when the reordering function is
used, at reception of a PDCP Data PDU from lower layers, the UE
shall: . . . else if received PDCP SN >= Next_PDCP_RX_SN: use
COUNT based on RX_HFN and the received PDCP SN for deciphering the
PDCP PDU; set Next_PDCP_RX_SN to the received PDCP SN + 1; if
Next_PDCP_RX_SN is larger than Maximum_PDCP_SN: set Next_PDCP_RX_SN
to 0; increment RX_HFN by one; . . . if the PDCP PDU has not been
discarded in the above: if the PDCP PDU with SN = 0 is received on
the duplication logical channel and no PDCP PDU except for the PDCP
PDU with SN = 0 has been received on the associated non-duplication
logical channel: discard the PDCP PDU; if a PDCP SDU with the same
PDCP SN is stored: discard the PDCP PDU; else: perform deciphering
of the PDCP PDU and store the resulting PDCP SDU; if received PDCP
SN = Last_Submitted_PDCP_RX_SN + 1 or received PDCP SN =
Last_Submitted_PDCP_RX_SN - Maximum_PDCP_SN: deliver to upper
layers in ascending order of the associated COUNT value: all stored
PDCP SDU(s) with consecutively associated COUNT value(s) starting
from the COUNT value associated with the received PDCP PDU; set
Last_Submitted_PDCP_RX_SN to the PDCP SN of the last PDCP SDU
delivered to upper layers;
TABLE-US-00007 Text proposal on top of [5] for TS38.323 - Example
2-4 5.1.2.1.4.1 Procedures when a PDCP PDU is received from the
lower layers For DRBs mapped on RLC AM, SLRB for duplicated
transmission and for LWA bearers, when the reordering function is
used, at reception of a PDCP Data PDU from lower layers, the UE
shall: . . . else if received PDCP SN >= Next_PDCP_RX_SN: use
COUNT based on RX_HFN and the received PDCP SN for deciphering the
PDCP PDU; set Next_PDCP_RX_SN to the received PDCP SN + 1; if
Next_PDCP_RX_SN is larger than Maximum_PDCP_SN: set Next_PDCP_RX_SN
to 0; increment RX_HFN by one; . . . if the PDCP PDU has not been
discarded in the above: if a PDCP SDU with the same PDCP SN is
stored; or if the PDCP PDU with SN = 0 is received on the
duplication logical channel and no PDCP PDU except for the PDCP PDU
with SN = 0 has been received on the associated non-duplication
logical channel: discard the PDCP PDU; else: perform deciphering of
the PDCP PDU and store the resulting PDCP SDU; if received PDCP SN
= Last_Submitted_PDCP_RX_SN + 1 or received PDCP SN =
Last_Submitted_PDCP_RX_SN - Maximum_PDCP_SN: deliver to upper
layers in ascending order of the associated COUNT value: all stored
PDCP SDU(s) with consecutively associated COUNT value(s) starting
from the COUNT value associated with the received PDCP PDU; set
Last_Submitted_PDCP_RX_SN to the PDCP SN of the last PDCP SDU
delivered to upper layers;
TABLE-US-00008 Text proposal on top of [5] for TS38.323 - Example
2-5 5.1.2.1.4.1 Procedures when a PDCP PDU is received from the
lower layers For DRBs mapped on RLC AM, SLRB for duplicated
transmission and for LWA bearers, when the reordering function is
used, at reception of a PDCP Data PDU from lower layers, the UE
shall: . . . else if received PDCP SN >= Next_PDCP_RX_SN: use
COUNT based on RX_HFN and the received PDCP SN for deciphering the
PDCP PDU; set Next_PDCP_RX_SN to the received PDCP SN + 1; if
Next_PDCP_RX_SN is larger than Maximum_PDCP_SN: set Next_PDCP_RX_SN
to 0; increment RX_HFN by one; . . . if the PDCP PDU has not been
discarded in the above: if a PDCP SDU with the same PDCP SN is
stored: discard the PDCP PDU; else: perform deciphering of the PDCP
PDU and store the resulting PDCP SDU; if received PDCP SN =
Last_Submitted_PDCP_RX_SN + 1 or received PDCP SN =
Last_Submitted_PDCP_RX_SN - Maximum_PDCP_SN: deliver to upper
layers in ascending order of the associated COUNT value: all stored
PDCP SDU(s) with consecutively associated COUNT value(s) starting
from the COUNT value associated with the received PDCP PDU, except
for the PDCP SDU with SN = 0 if this PDCP SDU is received on the
duplication logical channel and no PDCP SDU except for the PDCP SDU
with SN = 0 received on the associated non-duplication logical
channel has been delivered to upper layers; set
Last_Submitted_PDCP_RX_SN to the PDCP SN of the last PDCP SDU
delivered to upper layers;
TABLE-US-00009 Text proposal on top of [5] for TS38.323 - Example
2-6 5.1.2.1.4.1 Procedures when a PDCP PDU is received from the
lower layers For DRBs mapped on REC AM, SLRB for duplicated
transmission and for LWA bearers, when the reordering function is
used, at reception of a PDCP Data PDU from lower layers, the UE
shall: . . . else if received PDCP SN >= Next_PDCP_RX_SN: use
COUNT based on RX_HFN and the received PDCP SN for deciphering the
PDCP PDU; set Next_PDCP_RX_SN to the received PDCP SN + 1; if
Next_PDCP_RX_SN is larger than Maximum_PDCP_SN: set Next_PDCP_RX_SN
to 0; increment RX_HFN by one; . . . if the PDCP PDU has not been
discarded in the above: if a PDCP SDU with the same PDCP SN is
stored: discard the PDCP PDU; else: perform deciphering of the PDCP
PDU and store the resulting PDCP SDU; if received PDCP SN =
Last_Submitted_PDCP_RX_SN + 1 or received PDCP SN =
Last_Submitted_PDCP_RX_SN - Maximum_PDCP_SN: deliver to upper
layers in ascending order of the associated COUNT value: all stored
PDCP SDU(s) with consecutively associated COUNT value(s) starting
from the COUNT value associated with the received PDCP PDU, except
for the PDCP SDU with SN = 0 if this PDCP SDU is received on the
duplication logical channel and no PDCP SDU except for the PDCP SDU
with SN = 0 has been received on the associated non-duplication
logical channel; set Last_Submitted_PDCP_RX_SN to the PDCP SN of
the last PDCP SDU delivered to upper layers;
TABLE-US-00010 Text proposal on top of [5] for TS38.323 - Example
2-7 5.1.2.1.4.1 Procedures when a PDCP PDU is received from the
lower layers For DRBs mapped on RLC AM, SLRB for duplicated
transmission and for LWA bearers, when the reordering function is
used, at reception of a PDCP Data PDU from lower layers, the UE
shall: . . . else if received PDCP SN >= Next_PDCP_RX_SN: use
COUNT based on RX_HFN and the received PDCP SN for deciphering the
PDCP PDU; set Next_PDCP_RX_SN to the received PDCP SN + 1; if
Next_PDCP_RX_SN is larger than Maximum_PDCP_SN: set Next_PDCP_RX_SN
to 0; increment RX_HFN by one; . . . if the PDCP PDU has not been
discarded in the above: if the PDCP PDU is the very first PDCP PDU
with SN = 0 received on the duplication logical channel before
Next_PDCP_RX_SN wraps around and the PDCP SDU with SN = 0 received
on the associated non-duplication logical channel has been
delivered to upper layers: discard the PDCP PDU; if a PDCP SDU with
the same PDCP SN is stored: discard the PDCP PDU; else: perform
deciphering of the PDCP PDU and store the resulting PDCP SDU; if
received PDCP SN = Last_Submitted_PDCP_RX_SN + 1 or received PDCP
SN = Last_Submitted_PDCP_RX_SN - Maximum_PDCP_SN: deliver to upper
layers in ascending order of the associated COUNT value: all stored
PDCP SDU(s) with consecutively associated COUNT value(s) starting
from the COUNT value associated with the received PDCP PDU; set
Last_Submitted_PDCP_RX_SN to the PDCP SN of the last PDCP SDU
delivered to upper layers;
TABLE-US-00011 Text proposal on top of [5] for TS38.323 - Example
2-8 5.1.2.1.4.1 Procedures when a PDCP PDU is received from the
lower layers For DRBs mapped on RLC AM, SLRB for duplicated
transmission and for LWA bearers, when the reordering function is
used, at reception of a PDCP Data PDU from lower layers, the UE
shall: . . . else if received PDCP SN >= Next_PDCP_RX_SN: use
COUNT based on RX_HFN and the received PDCP SN for deciphering the
PDCP PDU; set Next_PDCP_RX_SN to the received PDCP SN + 1; if
Next_PDCP_RX_SN is larger than Maximum_PDCP_SN: set Next_PDCP_RX_SN
to 0; increment RX_HFN by one; . . . if the PDCP PDU has not been
discarded in the above: if the PDCP PDU is the very first PDCP PDU
with SN = 0 received on the duplication logical channel before
Next_PDCP_RX_SN wraps around and the PDCP PDU with SN = 0 received
on the associated non-duplication logical channel has been received
on the associated non-duplication logical channel: discard the PDCP
PDU; if a PDCP SDU with the same PDCP SN is stored: discard the
PDCP PDU; else: perform deciphering of the PDCP PDU and store the
resulting PDCP SDU; if received PDCP SN = Last_Submitted_PDCP_RX_SN
+ 1 or received PDCP SN = Last_Submitted_PDCP_RX_SN -
Maximum_PDCP_SN: deliver to upper layers in ascending order of the
associated COUNT value: all stored PDCP SDU(s) with consecutively
associated COUNT value(s) starting from the COUNT value associated
with the received PDCP PDU; set Last_Submitted_PDCP_RX_SN to the
PDCP SN of the last PDCP SDU delivered to upper layers;
[0208] In another alternative, the (receiving) UE could
conditionally maintain parameter(s) used for sidelink reception.
The UE could receive a PDCP PDU (with SN=0) on a first logical
channel. The UE could also receive a PDCP PDU (with SN=0) on a
second logical channel. The PDCP PDU (with SN=0) received on the
second logical channel could be a duplicate of the PDCP PDU (with
SN=0) received on the first logical channel. A PDCP SDU of the PDCP
PDU (with SN=0) received on the second logical channel could be the
same as a PDCP SDU of the PDCP PDU (with SN=0) received on the
first logical channel. The first logical channel could be a
non-duplication logical channel. The second logical channel could
be a duplication logical channel. The duplication logical channel
could be associated with the non-duplication logical channel.
[0209] In one embodiment, the UE could (start to) maintain the
parameter(s) used for sidelink reception if a first PDCP PDU is
received on the first logical channel. The SN of the first PDCP PDU
could be `0`. For example, the value of the parameter(s) used for
sidelink reception could be `0` before receiving the first PDCP PDU
on the first logical channel. For example, the UE could set the
parameter(s) used for sidelink reception based on the SN of the
first PDCP PDU when the first PDCP PDU is received on the first
logical channel, or based on the SN of the first PDCP PDU after
receiving the first PDCP PDU on the first logical channel. The UE
could set the parameter(s) used for sidelink reception based on the
SN of the first PDCP PDU upon reception of the first PDCP PDU on
the first logical channel. The parameter(s) used for sidelink
reception could be set to the SN of the first PDCP PDU+1 (=`1`).
The UE could (start to) perform a procedure (as specified in
Section 5.1.2.1.4.1 "Procedures when a PDCP PDU is received from
the lower layers" of 3GPP R2-1808921) used to handling the first
PDCP PDU received from lower layer (with maintaining the
parameter(s) used for sidelink reception).
[0210] In one embodiment, the UE could maintain the parameter(s)
used for sidelink reception if a second PDCP PDU is received on the
first logical channel. The SN of the second PDCP PDU could be
different from the SN of the first PDCP PDU. The SN of the second
PDCP PDU could be `1` or larger than the SN of the first PDCP PDU.
For example, the value of the parameter(s) used for sidelink
reception could be `1` before receiving the second PDCP PDU on the
first logical channel. The UE could set the parameter(s) used for
sidelink reception based on the SN of the second PDCP PDU when the
second PDCP PDU is received on the first logical channel, based on
the SN of the second PDCP PDU after receiving the second PDCP PDU
on the first logical channel, or based on the SN of the second PDCP
PDU upon reception of the second PDCP PDU on the first logical
channel. The parameter(s) used for sidelink reception could be set
to the SN of the second PDCP PDU+1 (=`2`). The UE could perform a
procedure (as specified in Session 5.1.2.1.4.1 "Procedures when a
PDCP PDU is received from the lower layers" of 3GPP R2-1808921)
used to handling the second PDCP PDU received from lower layer
(with maintaining the parameter(s) used for sidelink
reception).
[0211] If the SN of the second PDCP PDU could be the same as the SN
of the first PDCP PDU, the UE could (start to) not maintain the
parameter(s) used for sidelink reception. The SN of the second PDCP
PDU could be `0`. For example, the value of the parameter(s) used
for sidelink reception could `1` before receiving the second PDCP
PDU on the first logical channel. For example, the UE could not set
the parameter(s) used for sidelink reception based on the SN of the
second PDCP PDU when the second PDCP PDU is received on the first
logical channel, based on the SN of the second PDCP PDU after
receiving the second PDCP PDU on the first logical channel, or
based on the SN of the second PDCP PDU upon reception of the second
PDCP PDU on the first logical channel. The parameter(s) used for
sidelink reception could be (maintained as) the SN of the first
PDCP PDU+1 (=`1`). The parameter(s) used for sidelink reception
could be released. The UE could not perform a procedure (as
specified in Section 5.1.2.1.4.1 "Procedures when a PDCP PDU is
received from the lower layers" of 3GPP R2-1808921) used to
handling the second PDCP PDU received from lower layer (with
maintaining the parameter(s) used for sidelink reception).
Alternatively, the UE could perform another procedure (as specified
in Section 5.1.2.1.3 "Procedures for DRBs mapped on RLC UM" of 3GPP
TS 36.323) used to handling the second PDCP PDU received from lower
layer (without maintaining the parameter(s) used for sidelink
reception).
[0212] In one embodiment, the UE could (start to) maintain the
parameter(s) used for sidelink reception if a first PDCP PDU is
received on the second logical channel. The SN of the first PDCP
PDU could be `0`.
[0213] In one embodiment, the UE could maintain the parameter(s)
used for sidelink reception if a second PDCP PDU is received on the
second logical channel. The SN of the second PDCP PDU received on
the second logical channel could be different from the SN of the
first PDCP PDU received on the second logical channel. The SN of
the second PDCP PDU could be `1` or larger than the SN of the first
PDCP PDU.
[0214] In one embodiment, the parameter(s) used for sidelink
reception could be Next_PDCP_RX_SN or RX_HFN.
[0215] In FIGS. 14, 15, 16 and 17, the T could mean the timing of
the corresponding event. The larger number of T could mean the
corresponding event occurs later than or together with the event of
T with smaller number.
[0216] FIG. 18 is a flow chart 1800 according to one exemplary
embodiment from the perspective of a UE. In step 1805, the UE sets
a state variable used for the sidelink transmission to "1" when a
PDCP entity for the sidelink radio bearer is established. In step
1810, the UE performs the sidelink transmission for a very first
data unit of the PDCP entity on the sidelink radio bearer, wherein
a sequence number of the very first data unit is set to the state
variable.
[0217] In one embodiment, the UE could set the state variable to
"1" if duplication is enable on the sidelink radio bearer. The UE
could also set the state variable to "0" if duplication is disable
on the sidelink radio bearer.
[0218] In one embodiment, the UE could establish a first logical
channel and a second logical channel, wherein the first logical
channel and the second logical channel are associated with the
sidelink radio bearer.
[0219] In one embodiment, the UE could generate a duplicated data
unit, wherein the duplicated data unit is a duplicate of the very
first data unit. The UE could also deliver the very first data unit
to the first logical channel and the duplicated data unit to the
second logical channel for the sidelink transmission. In one
embodiment, the duplicated data unit could be a PDCP PDU.
[0220] In one embodiment, the state variable could be
Next_PDCP_TX_SN. The sequence number could be a PDCP sequence
number. The data unit could be a PDCP PDU.
[0221] Referring back to FIGS. 3 and 4, in one exemplary embodiment
of a UE, the device 300 includes a program code 312 stored in the
memory 310. The CPU 308 could execute program code 312 to enable
the UE (i) to set a state variable used for the sidelink
transmission to "1" when a PDCP entity for the sidelink radio
bearer is established, and (ii) to perform the sidelink
transmission for a very first data unit of the PDCP entity on the
sidelink radio bearer, wherein a sequence number of the very first
data unit is set to the state variable. Furthermore, the CPU 308
can execute the program code 312 to perform all of the
above-described actions and steps or others described herein.
[0222] FIG. 19 is a flow chart 1900 according to one exemplary
embodiment from the perspective of a UE. In step 1905, the UE
generates a data unit for transmission on a radio bearer, wherein
the data unit is a very first data unit to be transmitted on the
radio bearer. In step 1910, the UE sets a sequence number of the
data unit to a first value if duplication is enable on the radio
bearer. In step 1915, the UE sets the sequence number of the data
unit to a second value if duplication is disable on the radio
bearer, wherein the second value is different from the first
value.
[0223] In one embodiment, the UE could transmit the data unit with
the sequence number to a second UE. The data unit could be a PDCP
SDU. The radio bearer is a sidelink radio bearer. The first value
could be "1" or a number larger than "0". The second value could be
"0".
[0224] In one embodiment, the sequence number could be a PDCP SN.
The sequence number could be set based on Next_PDCP_TX_SN. The
Next_PDCP_TX_SN could initially be set to "0", and could be
incremented by one before setting the sequence number.
Alternatively, the Next_PDCP_TX_SN could initially be set to
"1".
[0225] In one embodiment, the duplication could be enabled on the
radio bearer if PDCP duplication transmission is configured.
Furthermore, the duplication could be enabled on the radio bearer
if a reliability of the radio bearer is higher than or equal to a
threshold.
[0226] In one embodiment, the duplication could be disabled on the
radio bearer if PDCP duplication transmission is configured.
Furthermore, the duplication could be disabled on the radio bearer
if a reliability of the radio bearer is lower than a threshold. The
reliability of the radio bearer could be a PPPR. The threshold
could be provided in a configuration used to configure the PDCP
duplication transmission.
[0227] In one embodiment, the UE could generate a PDCP PDU for
transmission of the data unit if the duplication is disabled on the
radio bearer. The PDCP PDU could be transmitted on a
non-duplication logical channel.
[0228] In one embodiment, the UE could generate a first PDCP PDU
for transmission of the data unit and a second PDCP PDU for
transmission of the data if the duplication is enable on the radio
bearer. The first PDCP PDU could be transmitted on a
non-duplication logical channel. The second PDCP PDU could be
transmitted on a duplication logical channel.
[0229] Referring back to FIGS. 3 and 4, in one exemplary embodiment
of a UE, the device 300 includes a program code 312 stored in the
memory 310. The CPU 308 could execute program code 312 to enable
the UE (i) to generate a data unit for transmission on a radio
bearer, wherein the data unit is a very first data unit to be
transmitted on the radio bearer, (ii) to set a sequence number of
the data unit to a first value if duplication is enable on the
radio bearer, and (iii) to set the sequence number of the data unit
to a second value if duplication is disable on the radio bearer,
wherein the second value is different from the first value.
Furthermore, the CPU 308 can execute the program code 312 to
perform all of the above-described actions and steps or others
described herein.
[0230] FIG. 20 is a flow chart 2000 according to one exemplary
embodiment from the perspective of a UE. In step 2005, the UE
receives a second data unit with a sequence number on a duplication
logical channel. In step 2010, the UE delivers the second data unit
to upper layer if a first data unit with the sequence number has
not been received on a non-duplication logical channel. In step
2015, the UE does not delivering the second data unit to the upper
layer if the first data unit with the sequence number has been
received on the non-duplication logical channel.
[0231] In one embodiment, the first data unit could be received
from a second UE, and the second data unit could be received from
the second UE. The sequence number could be "0". The sequence
number could also be a PDCP SN. The first data unit could be a
first PDCP SDU, and the second data unit could be a second PDCP
SDU. In one embodiment, the first data unit could be the same as
the second data unit.
[0232] In one embodiment, the upper layer could be a layer on top
of a PDCP layer of the first UE. The upper layer could be an IP
layer or an application layer.
[0233] Referring back to FIGS. 3 and 4, in one exemplary embodiment
of a UE, the device 300 includes a program code 312 stored in the
memory 310. The CPU 308 could execute program code 312 to enable
the UE (i) to receive a second data unit with a sequence number on
a duplication logical channel, (ii) to deliver the second data unit
to upper layer if a first data unit with the sequence number has
not been received on a non-duplication logical channel, and (iii)
to not deliver the second data unit to the upper layer if the first
data unit with the sequence number has been received on the
non-duplication logical channel. Furthermore, the CPU 308 can
execute the program code 312 to perform all of the above-described
actions and steps or others described herein.
[0234] FIG. 21 is a flow chart 2100 according to one exemplary
embodiment from the perspective of a UE. In step 2105, the UE
receives a first data unit with a first sequence number. In step
2110, the UE performs a first procedure to handle the first data
unit. In step 2115, the UE receives a second data unit with a
second sequence number. In step 2120, the UE performs the first
procedure to handle the second data unit if the second sequence
number is different from the first sequence number. In step 2125,
the UE performs a second procedure to handle the second data unit
if the second sequence number is the same as the first sequence
number.
[0235] In one embodiment, the first procedure used to handle the
first data unit could update a parameter used for reception based
on the first sequence number. The first sequence number could be
zero (0). The first procedure used to handle the second data unit
could update the parameter used for reception based on the second
sequence number if the second sequence number is different from the
first sequence number. The second sequence number could be larger
than zero (0).
[0236] In one embodiment, the second procedure used to handle the
second data unit may not update the parameter used for reception
based on the second sequence number if the second sequence number
is the same as the first sequence number. The second sequence
number could be zero (0).
[0237] In one embodiment, the first data unit could be received on
a non-duplication logical channel. The second data unit could be
received on a non-duplication logical channel. In particular, the
first data unit could be received from a second UE, and the second
data unit could be received from the second UE.
[0238] In one embodiment, the first data unit could be a PDCP SDU,
and the second data unit could be a PDCP SDU. The first data unit
could be a very first data unit received on the non-duplication
logical channel, and the second data unit may not be a very first
data unit received on the non-duplication logical channel.
[0239] In one embodiment, the first sequence number could be a PDCP
SN, and the second sequence number could be a PDCP SN. The
parameter used for reception could be Next_PDCP_RX_SN.
[0240] In one embodiment, the UE could set the parameter used for
reception to the first sequence number+1. Alternatively, the UE
could set the parameter used for reception to the second sequence
number+1 if the second sequence number is different from the first
sequence number. In addition, the UE may not set the parameter used
for reception to the second sequence number+1 if the second
sequence number is the same as the first sequence number.
[0241] In one embodiment, the non-duplication logical channel could
be associated with the duplication logical channel.
[0242] Referring back to FIGS. 3 and 4, in one exemplary embodiment
of a UE, the device 300 includes a program code 312 stored in the
memory 310. The CPU 308 could execute program code 312 to enable
the UE (i) to receive a first data unit with a first sequence
number, (ii) to perform a first procedure to handle the first data
unit, (iii) to receive a second data unit with a second sequence
number, (iv) to perform the first procedure to handle the second
data unit if the second sequence number is different from the first
sequence number, and (v) to perform a second procedure to handle
the second data unit if the second sequence number is the same as
the first sequence number. Furthermore, the CPU 308 can execute the
program code 312 to perform all of the above-described actions and
steps or others described herein.
[0243] Various aspects of the disclosure have been described above.
It should be apparent that the teachings herein could be embodied
in a wide variety of forms and that any specific structure,
function, or both being disclosed herein is merely representative.
Based on the teachings herein one skilled in the art should
appreciate that an aspect disclosed herein could be implemented
independently of any other aspects and that two or more of these
aspects could be combined in various ways. For example, an
apparatus could be implemented or a method could be practiced using
any number of the aspects set forth herein. In addition, such an
apparatus could be implemented or such a method could be practiced
using other structure, functionality, or structure and
functionality in addition to or other than one or more of the
aspects set forth herein. As an example of some of the above
concepts, in some aspects concurrent channels could be established
based on pulse repetition frequencies. In some aspects concurrent
channels could be established based on pulse position or offsets.
In some aspects concurrent channels could be established based on
time hopping sequences. In some aspects concurrent channels could
be established based on pulse repetition frequencies, pulse
positions or offsets, and time hopping sequences.
[0244] Those of skill in the art would understand that information
and signals may be represented using any of a variety of different
technologies and techniques. For example, data, instructions,
commands, information, signals, bits, symbols, and chips that may
be referenced throughout the above description may be represented
by voltages, currents, electromagnetic waves, magnetic fields or
particles, optical fields or particles, or any combination
thereof.
[0245] Those of skill would further appreciate that the various
illustrative logical blocks, modules, processors, means, circuits,
and algorithm steps described in connection with the aspects
disclosed herein may be implemented as electronic hardware (e.g., a
digital implementation, an analog implementation, or a combination
of the two, which may be designed using source coding or some other
technique), various forms of program or design code incorporating
instructions (which may be referred to herein, for convenience, as
"software" or a "software module"), or combinations of both. To
clearly illustrate this interchangeability of hardware and
software, various illustrative components, blocks, modules,
circuits, and steps have been described above generally in terms of
their functionality. Whether such functionality is implemented as
hardware or software depends upon the particular application and
design constraints imposed on the overall system. Skilled artisans
may implement the described functionality in varying ways for each
particular application, but such implementation decisions should
not be interpreted as causing a departure from the scope of the
present disclosure.
[0246] In addition, the various illustrative logical blocks,
modules, and circuits described in connection with the aspects
disclosed herein may be implemented within or performed by an
integrated circuit ("IC"), an access terminal, or an access point.
The IC may comprise a general purpose processor, a digital signal
processor (DSP), an application specific integrated circuit (ASIC),
a field programmable gate array (FPGA) or other programmable logic
device, discrete gate or transistor logic, discrete hardware
components, electrical components, optical components, mechanical
components, or any combination thereof designed to perform the
functions described herein, and may execute codes or instructions
that reside within the IC, outside of the IC, or both. A general
purpose processor may be a microprocessor, but in the alternative,
the processor may be any conventional processor, controller,
microcontroller, or state machine. A processor may also be
implemented as a combination of computing devices, e.g., a
combination of a DSP and a microprocessor, a plurality of
microprocessors, one or more microprocessors in conjunction with a
DSP core, or any other such configuration.
[0247] It is understood that any specific order or hierarchy of
steps in any disclosed process is an example of a sample approach.
Based upon design preferences, it is understood that the specific
order or hierarchy of steps in the processes may be rearranged
while remaining within the scope of the present disclosure. 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.
[0248] The steps of a method or algorithm described in connection
with the aspects disclosed herein may be embodied directly in
hardware, in a software module executed by a processor, or in a
combination of the two. A software module (e.g., including
executable instructions and related data) and other data may reside
in a data memory such as RAM memory, flash memory, ROM memory,
EPROM memory, EEPROM memory, registers, a hard disk, a removable
disk, a CD-ROM, or any other form of computer-readable storage
medium known in the art. A sample storage medium may be coupled to
a machine such as, for example, a computer/processor (which may be
referred to herein, for convenience, as a "processor") such the
processor can read information (e.g., code) from and write
information to the storage medium. A sample storage medium may be
integral to the processor. The processor and the storage medium may
reside in an ASIC. The ASIC may reside in user equipment. In the
alternative, the processor and the storage medium may reside as
discrete components in user equipment. Moreover, in some aspects
any suitable computer-program product may comprise a
computer-readable medium comprising codes relating to one or more
of the aspects of the disclosure. In some aspects a computer
program product may comprise packaging materials.
[0249] While the invention has been described in connection with
various aspects, it will be understood that the invention is
capable of further modifications. This application is intended to
cover any variations, uses or adaptation of the invention
following, in general, the principles of the invention, and
including such departures from the present disclosure as come
within the known and customary practice within the art to which the
invention pertains.
* * * * *