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YD/T 3340-2018 (YD/T3340-2018)

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YD/T 3340-2018: PDF in English (YDT 3340-2018)
YD/T 3340-2018
YD
COMMUNICATION INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 33.060.99
M36
Technical requirements of air interface of LTE-based
vehicular communication
ISSUED ON: DECEMBER 21, 2018
IMPLEMENTED ON: APRIL 01, 2019
Issued by: Ministry of Industry and Information Technology of PRC
Table of Contents
Foreword ... 3 
Introduction ... 4 
1 Scope ... 5 
2 Normative references ... 5 
3 Abbreviations ... 6 
4 Overview ... 9 
5 PC5 interface technical requirements ... 11 
5.1 Physical layer ... 11 
5.2 MAC layer... 52 
5.3 RLC layer ... 69 
5.4 PDCP layer ... 70 
5.5 RRC layer ... 72 
5.6 UE process in idle mode ... 178 
6 Uu interface's technical requirements ... 180 
6.1 Physical layer ... 180 
6.2 MAC layer... 184 
6.3 RLC layer ... 185 
6.4 PDCP layer ... 185 
6.5 RRC layer ... 185 
6.6 UE process in idle mode ... 200 
Technical requirements of air interface of LTE-based
vehicular communication
1 Scope
This standard specifies the air interface technical requirements for the LTE-
based vehicular communication technology, including the PC5 interface
technical requirements for the sidelink communication mode between terminals,
as well as the Uu interface technical requirements for the uplink/downlink
communication mode between the terminal and the base station. It specifies
the physical layer, MAC layer, RLC layer, PDCP layer, RRC layer as well as the
UE process in idle mode under these two working modes.
This standard applies to LTE-based vehicular communication systems,
including V2V, V2I, V2P, V2N communication scenarios.
2 Normative references
The following documents are essential to the application of this document. For
the dated documents, only the versions with the dates indicated are applicable
to this document; for the undated documents, only the latest version (including
all the amendments) is applicable to this standard.
YD/T 3340-2018 Technical requirements of air interface of LTE-based
vehicular communication
3GPP TS 23.285 (Release 14) Technical Specification Group Services and
System Aspects; Architecture enhancements for V 2X services
3GPP TS 24.334 (Release 14) Proximity-services (ProSe) User Equipment
(UE) to ProSe function protocol aspects; Stage 3
3GPP TS 24.386 (Release 14) User Equipment (UE) to V2X control function;
protocol aspects; Stage 3
3GPP TS 36.101 (Release 14) Evolved Universal Terrestrial Radio Access
(E-UTRA); User Equipment (UE) radio transmission and reception
3GPP TS 36.133 (Release 14) Evolved Universal Terrestrial Radio Access
(E-UTRA); Requirements for support of radio management
3GPP TS 36.211 (Release 14) Evolved Universal Terrestrial Radio Access
(E-UTRA); Physical channels and modulation
3GPP TS 36.212 (Release 14) Evolved Universal Terrestrial Radio Access
(E-UTRA); Multiplexing and channel coding
3GPP TS 36.213 (Release 14) Evolved Universal Terrestrial Radio Access
(E-UTRA); Physical layer procedures
3GPP TS 36.214 (Release 14) Evolved Universal Terrestrial Radio Access
(E-UTRA); Physical layer - Measurements
3GPP TS 36.304 (Release 14) Evolved Universal Terrestrial Radio Access
(E-UTRA); User Equipment (UE) procedures in idle mode
3GPP TS 36.321 (Release 14) Evolved Universal Terrestrial Radio Access
(E-UTRA); Medium Access Control (MAC) protocol specification
3GPP TS 36.322 (Release 14) Evolved Universal Terrestrial Radio Access
(E-UTRA); Radio Link Control (RLC) protocol specification
3GPP TS 36.323 (Release 14) Evolved Universal Terrestrial Radio Access
(E-UTRA); Packet Data Convergence Protocol (PDCP) Specification
3GPP TS 36.331 (Release 14) Evolved Universal Terrestrial Radio Access
(E-UTRA); Radio Resource Control (RRC) Protocol specification
3 Abbreviations
The following abbreviations apply to this document.
3GPP: The 3rd Generation Partnership Project
AM: Acknowledged Mode
BSR: Buffer Status Report
CBR: Channel Busy Ratio
CR: Channel Occupancy Ratio
CRC: Cyclic Redundancy Check
CSI: Channel Status Indicator
DCI: Downlink Control Information
DL: Downlink
PRACH: Physical Random Access Channel
PRB: Physical Resource Block
PSBCH: Physical Sidelink Broadcast Channel
PSCCH: Physical Sidelink Control Channel
PSSCH: Physical Sidelink Shared Channel
PSSS: Primary Sidelink Synchronization Signal
PUCCH: Physical Uplink Control Channel
PUSCH: Physical Uplink Shared Channel
QAM: Quadrature Amplitude Modulation
QPSK: Quadrature Phase Shift Keying
RB: Resource Block
RIV: Resource Indication Value
RLC: Radio Link Control
RNTI: Radio Network Temporary Identifier
RRC: Radio Resource Control
RSRP: Reference Signal Received Power
SBCCH: Sidelink Broadcast Control Channel
SCell: Secondary Cell
SCI: Sidelink Control Information
SC-FDMA: Single Carrier Frequency Division Multiplex Access
SDU: Service Data Unit
SFN: System Frame Number
SIB: System Information Block
SL: Sidelink
SL-BCH: Sidelink Broadcast Channel
SL-SCH: Sidelink Share Channel
interface; the other is the uplink/downlink communication mode between the
terminal and the base station, where the air interface between the terminal and
the base station is called Uu interface.
Chapter 5 specifies the technical requirements for the PC5 interface of the LTE-
based wireless communication technology for vehicular networking. The
sidelink's communication method includes two transmission modes. Among
them, the sidelink transmission mode 3 is resource scheduling allocation, whilst
the sidelink transmission mode 4 is the UE's independent resource selection.
For specific definitions, see 7.2.2 of YD/T 3340-2018 Technical requirements of
air interface of LTE-based vehicular communication.
The correspondence between the document structure and content of Chapter
5 and the 3GPP technical specifications is as follows.
- 5.1 specifies the technical requirements for the physical layer.
- 5.1.1 specifies the physical channel and modulation, corresponding to
3GPP TS 36.211 (Release 14).
- 5.1.2 specifies multiplexing and channel coding, corresponding to 3GPP TS
36.212 (Release 14).
- 5.1.3 specifies the physical layer process, corresponding to 3GPP TS
36.213 (Release 14).
- 5.1.4 specifies physical layer measurement, corresponding to 3GPP TS
36.214 (Release 14).
- 5.2 specifies the technical requirements for the Medium Access Control
(MAC) layer, corresponding to 3GPP TS 36.321 (Release 14).
- 5.3 specifies the technical requirements for the Radio Link Control (RLC)
layer, corresponding to 3GPP TS 36.322 (Release 14).
- 5.4 specifies the technical requirements of the Packet Data Convergence
Protocol (PDCP) layer, corresponding to 3GPP TS 36.323 (Release 14).
- 5.5 specifies the technical requirements for the Radio Resource Control
(RRC) layer, corresponding to 3GPP TS 36.331 (Release 14).
- 5.6 specifies the UE process technical requirements in idle mode,
corresponding to 3GPP TS 36.304 (Release 14).
Chapter 6 specifies the technical requirements for the Uu interface of the LTE-
based wireless communication technology for the vehicular networking.
The correspondence between the document structure and content of Chapter
5.1.1.2.5 Resource pool
The 5.1.3 defines the subframe pool and resource block pool.
For PSSCH, the current time slot number in the subframe pool is
, where is the current time slot number in the
current sidelink subframe , where k is equal to the footnote of
; is defined by the sidelink transmission mode 3 in 5.1.3.2.1.2, or defined
by the sidelink transmission mode 4 in 5.1.3.2.1.3.
5.1.1.2.6 Guard interval
The last SC-FDMA symbol of the sidelink subframe is used as a guard interval
and cannot be used for sidelink transmission.
5.1.1.3 Physical shared channel of sidelink
5.1.1.3.1 Scrambling
The bit block (where Mbit is the number of bits sent)
transmitted on the PSSCH in a subframe shall be scrambled according to 5.3.1
of 3GPP TS 36.211 (Release 14).
The scrambling sequence shall be initialized at the beginning of each PSSCH
subframe according to , where for the sidelink
transmission mode 3 and the sidelink transmission mode 4, p and L are given
by 5.1.1 of 3GPP TS 36.212 (Release 14), is equal to the decimal
representation of the CRC check code of the PSCCH as sent in the same
subframe as the PSSCH.
5.1.1.3.2 Modulation
The modulation is performed according to 5.3.2 of 3GPP TS 36.211 (Release
14). The modulation mode of PSSCH is as shown in Table 3.
3GPP TS 36.211 (Release 14). For the sidelink transmission mode 3 and the
sidelink transmission mode 4, it is assumed that the sequence is generated
according to subframe 5.
Resource unit mapping: The sequence di(n) is multiplied by the amplitude
scaling factor to adjust the transmit power defined in 5.1.3.4; then
mapped to the resource element in the second time slot of the subframe on the
antenna port 1020. The mapping relationship is as shown in the formula (4).
5.1.1.7 Demodulation reference signal
The demodulation reference signals related to PSSCH, PSCCH, PSBCH
transmission shall be transmitted according to the PUSCH of 5.5.2.1 in 3GPP
TS 36.211 (Release 14); it include the following special cases.
- It shall use the parameters in Table 6, Table 7, Table 8.
- Replace PUSCH with PSSCH, PSCCH or PSBCH according to the physical
channel related to the reference signal.
- The antenna ports are given in Table 1.
- The physical resource block used in the mapping process shall be the same
as the corresponding PSSCH, PSCCH or PSBCH transmission.
- 3GPP TS 36.211 (Release 14) 5.5.2.1.2 stipulates that the index k in the
mapping process shall be the same as the corresponding PSSCH, PSCCH
or PSBCH transmission.
■For PSSCH and PSCCH in sidelink transmission mode 3 and sidelink
transmission mode 4, when mapping in the first time slot of a subframe,
it shall use the parameters l = 2 and l = 5; when mapping in the second
time slot of a subframe, it shall use the parameters l = 1 and l = 4.
■For PSBCH in sidelink transmission mode 3 and sidelink transmission
mode 4, when mapping in the first time slot of a subframe, it shall use the
parameters l = 4 and l = 6; when mapping in the second time slot of a
subframe, it shall use the parameters l = 2.
- For sidelink transmission mode 3 and sidelink transmission mode 4, the
mapped to the highest significant bit of the transport block.
Set L=16bit, calculate and add CRC check bit according to 5.1.1 of 3GPP TS
36.212 (Release 14), to generate bit sequence c0, c1, c2, c3, …, cK-1, where ck
= bk (for k = 0, 1, 2, …, K-1, and K = A + L).
5.1.2.3.1.3 Channel coding
The information bits are sent to the channel coding module, denoted as c0, c1,
c2, c3, …, cK-1, where K is the number of bits, which uses a tail-biting
convolutional code with a code rate of 1/3 (according to the provisions of 5.1.3.1
of 3GPP TS 36.212 (Release 14).
The bit stream after channel coding is denoted as ,
where i = 0, 1 or 2, D is the number of bits of bit stream after the ith code, that
is, D = K.
5.1.2.3.1.4 Rate matching
The code block after tail-biting convolutional coding is sent to the rate matching
module, denoted as , where i = 0, 1, or 2, i is the bit stream
number, D is the number of bits in each coded bit stream. The code block is
subject to rate matching in accordance with the method of 5.1.4.1 of 3GPP TS
36.212 (Release 14).
The bit stream after rate matching is denoted as , where E is
the total number of bits after rate matching.
5.1.2.3.2 Sidelink shared channel (SL-SCH)
The sidelink shared channel (SL-SCH) is processed according to the downlink
shared channel processing procedure as specified in 5.3.2 of 3GPP TS 36.212
(Release 14), using code block concatenation coding with a code rate of 1/3
(according to 5.1.3.2 of 3GPP TS 36.212 (Release 14)), but with the following
differences.
- Data arrives at the coding unit in the form of at most one transmission block
per TTI.
- In the code block concatenation step, the coded bit sequence
corresponding to a transmission block after the code block concatenation
is regarded as a code word described in 5.1.1.3.1.
- According to 5.2.2.7 and 5.2.2.8 of 3GPP TS 36.212 (Release 14), PUSCH
interleaving operation without any control information shall be performed in
order to perform time domain first instead of frequency domain mapping,
- Time interval between initial transmission and retransmission: 4 bits, as
defined in 5.1.3.2.1.4.
- Modulation and coding method: 5 bits, as defined in 5.1.3.3.1.
- Retransmission index: 1 bit, as defined in 5.1.3.3.1.
- Added reserved information bits, until the length of SCI format 1 is 32 bits.
The value of the reserved information bit is 0.
5.1.2.3.4 DCI format 5A
DCI format 5A uses tail-biting convolutional coding with a code rate of 1/3 [as
specified in 5.1.3.1 of 3GPP TS 36.212 (Release 14)], which is used to schedule
PSCCH in sidelink transmission mode 3, meanwhile includes several fields of
SCI format 1 for scheduling PSSCH.
The following information is sent in DCI format 5A.
- Carrier indicator: 3 bits, as defined in 5.1.3.3.1.
- The minimum index of the sub-channel assigned to the initial transmission:
bits, as defined in 5.1.3.2.1.4.
- Field of SCI format 1, as defined in 5.1.2.3.3.3.
■ Frequency domain resource location for initial transmission and
retransmission.
■The time interval between initial transmission and retransmission.
- SL index: 2 bits, as defined in 5.1.3.3.1 (this field only appears in the case
of TDD duplex mode with an uplink and downlink ratio of 0 ~ 6).
When the CRC of DCI format 5A is scrambled by SL-SPS-V-RNTI, the following
fields are also included.
- SLSPS configuration index: 3 bits, as defined in 5.1.3.3.1.
- Activation/release indication: 1 bit, as defined in 5.1.3.3.1.
If the number of information bits in the DCI format 5A mapped to the search
space is smaller than the payload size of the DCI format 0 mapped to the same
search space, 0 shall be filled in the DCI format 5A, until the payload size of the
format 5A is equal to the payload size of the DCI format 0 including padding
bits.
If the CRC of DCI format 5A is scrambled by SL-V-RNTI, meanwhile the number
on a subframe, then the measured PSSCH-RSRP can be used for the
subframes before receiving SCI format 1 indicated by the SCI format 1. If the
SCI format 1 that schedules the same transport block is successfully decoded
in only one subframe, then the PSSCH-RSRP measured by the UE on the
subframe of the successfully decoded SCI format 1 can be used for another
subframe as indicated by the SCI format 1. The UE does not need to decode
the PSSCH before successfully decoding the corresponding SCI format 1.
5.1.3.2 Related processes of physical sidelink shared channel
5.1.3.2.1 UE procedure for transmitting PSSCH
5.1.3.2.1.1 Overview
If the UE sends SCI format 1 on the PSCCH of subframe n according to the
PSCCH resource configuration, then for the corresponding PSSCH
transmission on the same TB:
- For sidelink transmission mode 3.
■The determination of subframe set and resource block set shall be based
on the subframe pool indicated by PSSCH resource configuration
(specified in 5.1.3.2.3) and the "retransmission index and initial
retransmission time interval" field in SCI format 1 and the "initial
transmission and retransmission frequency domain resource location"
field (as specified in 5.1.3.2.1.4).
- For sidelink transmission mode 4:
■The determination of subframe set and resource block set shall be based
on the subframe pool indicated by PSSCH resource configuration
(specified in 5.1.3.2.3) and the "retransmission index and initial
retransmission time interval" field and "initial transmission and
retransmission frequency domain resource location" field (specified in
5.1.3.2.1.4).
- The modulation order is determined according to the "modulation coding
method" field (IMCS) in SCI format 1. For 0 ≤ IMCS ≤ 28, the modulation order
is set as Q' = min(4, Q'm), wherein Q'm shall be determined according to
Table 11.
the measured value Ex,y is defined as the linear average value of the
subchannel measurement the partial
subframe monitored in step b). When Prsvp_TX ≥ 100, the subframe
measured by Ex,y is expressed as and j is a negative integer;
When Prsvp_TX ≥ 100, the subframe measured by Ex,y is expressed as
and j is a negative integer.
i) The UE shall move the single subframe candidate resource with the
smallest measurement value Ex,y from the set SA to the set SB. This step
shall be repeated before the number of single subframe candidate
resources in the set SB is greater than or equal to 0.2•Mtotal.
UE will report the SB to higher layer.
If the upper layer has configured partial perception, the following steps shall
be performed.
a) A single subframe candidate resource Rx,y used for PSSCH transmission
is defined as a set of LsubCH consecutive subchannels x+j on the subframe
, where . The UE shall determine the set of subframes
consisting of at least Y subframes on the time interval
according to the implementation, where the selection of T1 and T2 depends
on the UE implementation and shall satisfy T1 ≤ 4 and 20 ≤ T2 ≤ 100. The
UE's selection of T2 shall meet the delay requirement and Y shall be
greater than or equal to the upper layer parameter minNumCandidateSF.
The UE shall assume any LsubCH consecutive subchannels in the
corresponding PSSCH resource pool in the determined subframe set as
single subframe candidate resources. The total number of candidate
resources in a single subframe is denoted as Mtotal.
b) For a subframe included in the subframe set in step a), if the kth bit of
the high-level parameter gapCandidateSensing is set to 1, the UE shall
monitor each subframe . The UE shall perform operations in
accordance with the following steps based on the PSCCH decoding and
S-RSSI measurement on these subframes.
c) The parameter Thα,b is set to the ith value in the SL-ThresPSSCH-RSRP
field of the SL-ThresPSSCH-RSRP-List, where i = α x 8 + b + 1.
d) Initialize the set SA as a set of all single-subframe candidate resources.
When a set of subframes is selected as a set of
PSSCH transmission opportunities, then the set of subframes
that is used as another set of PSSCH
transmission opportunities shall satisfy the conditions -15 ≤ K ≤ 15 and k≠0.
Among them, P'rsvp_TX = Pstep x Prsvp_TX/100 is the maximum value of PSSCH
transmission opportunities in a selected subframe set, Prsvp_TX is the resource
reservation time interval provided by the higher layer.
5.1.3.2.2 UE process for receiving PSSCH
For the sidelink transmission mode 3, by detecting SCI format 1 on the PSCCH,
the UE shall decode the PSSCH according to the detected SCI format 1,
meanwhile the corresponding PSSCH resource is configured by the higher
layer.
For the sidelink transmission mode 4, by detecting SCI format 1 on the PSCCH,
the UE shall decode the PSSCH according to the detected SCI format 1,
meanwhile the corresponding PSSCH resource is configured by the higher
layer.
5.1.3.2.3 UE process for determining PSSCH resource pool and subframe
pool for sidelink transmission mode 3 or 4
In sidelink transmission mode 3 or 4, the set of subframes that may belong to a
PSSCH resource pool is denoted as , where:
- 0 ≤ < 10240.
- The subframe index is related to the subframe #0 of the wireless structure,
wherein the subframe #0 of the wireless structure is consistent with the
SFN0 or DFN0 of the serving cell.
- The subframe set includes all subframes except the following subframes.
■The subframe which is set as SLSS resource.
■ The downlink subframes and special subframes when the sidelink
transmission occurs in a TDD cell.
■Reserved subframes determined according to the following steps.
Step 1) After the Nslss and Ndssf subframes shall be excluded from the set
of all subframes, the index of the remaining subframes are
arranged in ascending order, which is recorded as
Where:
j - j = 0, 1, …, nsubCHsize - 1;
nsubCHRBstart - Given by the high-level parameter startRBSubchannel;
nsubCHsize - Given by the high-level parameter sizeSubchannel.
5.1.3.3 Related processes of the physical sidelink control channel
5.1.3.3.1 UE process for transmitting PSCCH
5.1.3.3.1.1 UE process for transmitting PSCCH
For sidelink transmission mode 3.
- The UE shall determine the subframe and resource block for transmission
SCI format 1 according to the following steps.
■SCI format 1 is sent on each time slot of the corresponding PSSCH
subframe; it shall use 2 physical resource blocks.
■If the UE receives the SL-V-RNTI scrambled CRC's DCI format 5A on
subframe n, then one transmission of PSCCH shall be performed on the
PSCCH resource LInit (specified in 5.1.3.3.3) of subframe n + kinit, where
LInit the value in the "lowest sub-channel index allocated to the initial
transmission" field in the sidelink permit, kinit is the minimum integer which
is greater than or equal to 4+m and satisfies the conditions that the
subframe n + kinit is included in the determined according
to 5.1.3.2.3. If the corresponding DCI format 5A contains the "SL Index"
field determined according to Table 13, then the value of m is the value
indicated in the "SL Index" field, otherwise m = 0.
■If the “interval between initial transmission and retransmission” in the
configured sidelink permit is not equal to 0, then another PSSCH
transmission shall be performed on the PSCCH resource LReTX of
subframe , where SFgap is the value indicated in the "time
interval between initial transmission and retransmission" field in the
configured sidelink permit. LReTX corresponds to the value of as
determined according to the process of 5.1.3.2.1.4, which is the RIV
value as set in the "initial transmission and retransmission frequency
domain resource location" field in the configured sidelink permit.
■If the UE receives the SL-SPS-V-RNTI scrambled CRC's DCI format 5A
on subframe n, the UE shall consider the received DCI information as a
valid sidelink semi-continuous activation or release, whilst the semi-
continuous activation or release only corresponds to the SPS
configuration as indicated by the SL SPS configuration index field. If the
received DCI activates an SL SPS configuration, then one transmission
of PSCCH shall be performed on the PSCCH resource Lint (specified in
5.1.3.3.3) of subframe n+kinit, where Lint is value indicated by the “lowest
index of the sub-channel assigned to the initial transmission” in the
configured sidelink permit, kinit is the smallest integer that is greater than
or equal to 4+m and meets the condition that subframe n+kinit is included
in , wherein is determined according to
5.1.3.2.3. If the corresponding DCI format 5A contains the "SL Index" field
as determined according to Table 13, then the value of m is the value
indicated by the "SL Index" field, otherwise m = 0.
■If in the configured sidelink permit (3GPP TS 36.321 (Release 14)), the
"time interval between initial transmission and retransmission" value is
not equal to 0, then another PSCCH transmission shall be performed on
the PSCCH resource LReTX of subframe , where SFgap is the
value indicated in the "time interval between initial transmission and
retransmission" field in the configured sidelink permit. LReTX corresponds
to the value as determined according to 5.1.3.2.1.4, which is
the RIV value as set in the "initial transmission and retransmission
frequency domain resource location" field in the configured sidelink
permit.
- UE shall set the content in SCI format 1 according to the following
requirements.
■The UE shall set the modulation and coding method according to the
instructions of the higher layer.
■The UE shall set the "Priority" field according to the highest priority
among the corresponding transport block priorities indicated by the
higher layers.
■The UE shall set the "time interval between initial transmission and
retransmission" field, the "initial transmission and retransmission
frequency domain resource location" field, the "retransmission index"
field. The time domain and frequency domain resources determined for
PSSCH according to 5.1.3.2.1.4 shall be consistent with the PSSCH
allocated resources as indicated by the configured sidelink permit.
■The UE shall set the value of the resource reservation field to 0.
■Each transmission of SCI format 1 shall be performed on two physical
resource blocks in one subframe and each time slot of the subframe.
- The UE shall randomly select the cyclic shift bit ncs,λ from {0, 3, 6, 9} for
each time of PSCCH transmission.
For sidelink transmission mode 4.
- The UE shall determine the subframes and resource blocks for SCI format
transmission according to the following requirements.
■SCI format 1 shall be transmitted using two physical resource blocks in
each time slot of the corresponding PSSCH subframe.
■If the sidelink permit configured by the higher layer indicates the PSCCH
resource on subframe , then one transmission of PSCCH shall be
performed on the PSCCH resource m (specified in 5.1.3.3.3) indicated
on subframe .
■If the "time interval between initial transmission and retransmission" value
in the configured sidelink permit is not equal to 0, then another PSCCH
transmission shall be performed on the PSCCH resource LRcTX of
subframe , where SFgap is the value as indicated in the "time
interval between initial transmission and retransmission" field in the
configured sidelink permit; LRcTX corresponds to the value of as
determined in the process of 5.1.3.2.1.4. This value is the RIV value as
set in the "initial transmission and retransmission frequency field
resource location" in the configured sidelink permit.
- The UE shall set the content in SCI format 1 according to the following
requirements.
■The UE shall set the modulation and coding method according to the
instructions of the higher layer.
■The UE shall set the "Priority" field according to the highest priority
among the corresponding transport block priorities indicated by the
higher layers.
■The UE shall set the " time interval between initial transmission and
retransmission" field, the "initial transmission and retransmission
synchronization signal resource configuration of the corresponding sidelink.
5.1.3.5 Priority processing between SL and Uu
When the V2X sidelink transmission overlaps the Uu uplink transmission, if the
Uu uplink performs a random access procedure or the transmission priority is
high (such as emergency calls specified in 3GPP TS 24.386 (Release 14)), the
Uu uplink transmission is given priority (regardless of the PPPP value of the
MAC PDU of the sidelink).
When the V2X sidelink transmission overlaps with the Uu uplink transmission,
if the SCI "priority" field's setting value of the sidelink transmission is less than
the high-level parameter thresSL-TxPrioritization (the PPPP value of the
sidelink MAC PDU is lower than the (pre) configured PPPP threshold), the
priority of sidelink transmission is higher than the priority of Uu uplink
transmission, the sidelink transmission is given priority, or the UE reduces the
uplink transmission power, to ensure that in any overlapping part, its total
transmission power does not exceed the PCMAX as defined in 3 GPP TS 36.101
(Release 14). In this case, the calculation of the uplink transmit power
adjustment depends on the implementation.
When the V2X sidelink transmission overlaps with the Uu uplink transmission,
if the SCI "priority" field's setting value of the sidelink transmission is greater
than or equal to the higher-level parameters thresSL-TxPrioritization [The
PPPP value of the sidelink MAC PDU is higher than or equal to the (pre)
configured PPPP threshold], the priority of Uu uplink transmission is higher than
the priority of sidelink transmission, then the Uu uplink transmission is given
priority, or the UE reduces the transmission power of the sidelink, to ensure that
in any overlap, the total transmission power does not exceed the PCMAX as
defined in 3GPP TS 36.101 (Release 14). In this case, the calculation of the
sidelink transmission power's adjustment depends on the implementation.
5.1.4 Physical layer measurement
5.1.4.1 Overview
For V2X transmission based on the PC5 interface, the following UE physical
layer measurement is used.
- Sidelink received signal strength indicator (S-RSSI).
- PSSCH-Reference signal reception power (PSSCH-RSRP).
- Channel busy rate (CBR).
- Channel occupancy rate (CR).
5.1.4.2 UE measurement capability
5.1.4.2.4 Channel occupancy rate (CR)
Definition: The channel occupancy rate (CR) evaluated at subframe n is defined
as: the total number of subchannels used for transmission in subframe [n-α, n-
l] and permitted in subframe [n, n+b] divided by the total number of subchannels
configured on subframe [n-α, n+b] in the transmission resource pool.
Channel occupancy (CR) measurement is applicable to: RRC_IDLE same
frequency, RRC_IDLE different frequency, RRC_CONNECTED same
frequency, RRC_CONNECTED different frequency.
5.2 MAC layer
5.2.1 Overview
The services and functions provided by the MAC sublayer of the sidelink include:
radio resource selection, data packet filtering of sidelink communication and
V2X sidelink communication; the logical channel used for sidelink user plane
data transmission is the sidelink traffic channel (STCH). STCH is a point-to-
multipoint channel, which is used to transmit user information from one UE to
one or more other UE. The sidelink's MAC layer mainly includes the sidelink
share channel (SL-SCH)'s data transmission, the protocol data unit of sidelink
shared channel, format and parameters and other related content. SBCCH
uses MAC TM mode.
5...
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(Above excerpt was released on 2020-12-20, modified on 2022-02-20, translated/reviewed by: Wayne Zheng et al.)
Source: https://www.chinesestandard.net/PDF.aspx/YDT3340-2018