14.2.1 UE procedure for transmitting the PSCCH
36.2133GPPEvolved Universal Terrestrial Radio Access (E-UTRA)Physical layer proceduresRelease 17TS
For sidelink transmission mode 1and PSCCH period i,
- the UE shall determine the subframes and resource blocks for transmitting SCI format 0 as follows.
– SCI format 0 is transmitted in two subframes in the subframe pool and one physical resource block per slot in each of the two subframes, wherein the physical resource blocks belong to the resource block pool, where the subframe pool and the resource block pool are indicated by the PSCCH resource configuration (as defined in Clause 14.2.3)
– the two subframes and the resource blocks are determined using "Resource for PSCCH" field (
) in the configured sidelink grant (described in [8]) as described in Clause 14.2.1.1.
- the UE shall set the contents of the SCI format 0 as follows:
– the UE shall set the Modulation and coding scheme field according to the Modulation and coding scheme indicated by the higher layer parameter mcs-r12 if the parameter is configured by higher layers.
– the UE shall set the Frequency hopping flag according to the "Frequency hopping flag" field in the configured sidelink grant.
– the UE shall set the Resource block assignment and hopping resource allocation according to the "Resource block assignment and hopping resource allocation" field in the configured sidelink grant.
– the UE shall set the Time resource pattern according to the "Time resource pattern" field in the configured sidelink grant .
– the UE shall set the eleven-bit Timing advance indication to 
to indicate sidelink reception timing adjustment value using the NTA (defined in [3]) value for the UE in the subframe that is no earlier than subframe 
(
described in Clause 14.2.1.1).
For sidelink transmission mode 2,
– SCI format 0 is transmitted in two subframes in the subframe pool and one physical resource block per slot in each of the two subframes, wherein the physical resource blocks belongs to the resource block pool, where the subframe pool and the resource block pool are indicated by the PSCCH resource configuration (as defined in Clause 14.2.3)
– the two subframes and the resource blocks are determined using the procedure described in Clause 14.2.1.2
– the UE shall set the eleven-bit Timing advance indication 
in the SCI format 0 to zero.
For sidelink transmission mode 3,
– The UE shall determine the subframes and resource blocks for transmitting SCI format 1 as follows:
– SCI format 1 is transmitted in two physical resource blocks per slot in each subframe where the corresponding PSSCH is transmitted.
– If the UE receives in subframe n DCI format 5A with the CRC scrambled by the SL-V-RNTI, one transmission of PSCCH is in the PSCCH resource 
(described in Clause 14.2.4) in the first subframe that is included in 
and that starts not earlier than . 
is the value indicated by "Lowest index of the sub-channel allocation to the initial transmission" associated with the configured sidelink grant (described in [8]) if the field "Lowest index of the sub-channel allocation to the initial transmission" in the corresponding DCI format 5A is present and otherwise, 
is determined by Clause 14.1.5, the value m is indicated by ‘SL index’ field in the corresponding DCI format 5A according to Table 14.2.1-1 if this field is present and m=0 otherwise, is the start of the downlink subframe carrying the DCI, and and are described in [3].
– If "Time gap between initial transmission and retransmission" in the configured sidelink grant (described in [8]) is not equal to zero, another transmission of PSCCH is in the PSCCH resource 
in subframe 
, where is the value indicated by "Time gap between initial transmission and retransmission" field in the configured sidelink grant. 
corresponds to the value 
determined by the procedure in Clause 14.1.1.4C with the RIV set to the value indicated by "Frequency resource location of the initial transmission and retransmission" field in the configured sidelink grant.
– If the UE receives in subframe n DCI format 5A with the CRC scrambled by the SL-SPS-V-RNTI , the UE shall consider the received DCI information as a valid sidelink semi-persistent activation or release only for the SPS configuration indicated by the SL SPS configuration index field. If the received DCI activates an SL SPS configuration, one transmission of PSCCH is in the PSCCH resource 
(described in Clause 14.2.4) in the first subframe that is included in 
and that starts not earlier than . 
is the value indicated by "Lowest index of the sub-channel allocation to the initial transmission" associated with the configured sidelink grant (described in [8]) if the field "Lowest index of the sub-channel allocation to the initial transmission" in the corresponding DCI format 5A is present and otherwise, 
is determined by Clause 14.1.5, the value m is indicated by ‘SL index’ field in the corresponding DCI format 5A according to Table 14.2.1-1 if this field is present and m=0 otherwise, is the start of the downlink subframe carrying the DCI, and and are described in [3]..
– If "Time gap between initial transmission and retransmission" in the configured sidelink grant (described in [8]) is not equal to zero, another transmission of PSCCH is in the PSCCH resource 
in subframe 
, where is the value indicated by "Time gap between initial transmission and retransmission" field in the configured sidelink grant. 
corresponds to the value 
determined by the procedure in Clause 14.1.1.4C with the RIV set to the value indicated by "Frequency resource location of the initial transmission and retransmission" field in the configured sidelink grant.
– The UE shall set the contents of the SCI format 1 as follows:
– the UE shall set the Modulation and coding scheme as indicated by higher layers.
– the UE shall set the "Priority" field according to the highest priority among those priority(s) indicated by higher layers corresponding to the transport block. Priority field ‘000’ corresponds to priority ‘1’, priority field ‘001’ corresponds to priority ‘2’, and so on.
– the UE shall set the Time gap between initial transmission and retransmission field, the Frequency resource location of the initial transmission and retransmission field, and the Retransmission index field such that the set of time and frequency resources determined for PSSCH according to Clause 14.1.1.4C is in accordance with the PSSCH resource allocation indicated by the configured sidelink grant.
– the UE shall set the Resource reservation according to table 14.2.1-2 based on indicated value X, where X is equal to the Resource reservation interval provided by higher layers divided by 100.
– Each transmission of SCI format 1 is transmitted in one subframe and two physical resource blocks per slot of the subframe.
– The UE shall randomly select the cyclic shift 
among {0, 3, 6, 9} in each PSCCH transmission.
For sidelink transmission mode 4,
– The UE shall determine the subframes and resource blocks for transmitting SCI format 1 as follows:
– SCI format 1 is transmitted in two physical resource blocks per slot in each subframe where the corresponding PSSCH is transmitted.
– If the configured sidelink grant from higher layer indicates the PSCCH resource in subframe 
, one transmission of PSCCH is in the indicated PSCCH resource m (described in Clause 14.2.4) in subframe 
.
– If "Time gap between initial transmission and retransmission" in the configured sidelink grant (described in [8]) is not equal to zero, another transmission of PSCCH is in the PSCCH resource 
in subframe 
where is the value indicated by "Time gap between initial transmission and retransmission" field in the configured sidelink grant, 
corresponds to the value 
determined by the procedure in Clause 14.1.1.4C with the RIV set to the value indicated by "Frequency resource location of the initial transmission and retransmission" field in the configured sidelink grant.
– the UE shall set the contents of the SCI format 1 as follows:
– the UE shall set the Modulation and coding scheme as indicated by higher layers.
– the UE shall set the "Priority" field according to the highest priority among those priority(s) indicated by higher layers corresponding to the transport block. Priority field ‘000’ corresponds to priority ‘1’, priority field ‘001’ corresponds to priority ‘2’, and so on.
– the UE shall set the Time gap between initial transmission and retransmission field, the Frequency resource location of the initial transmission and retransmission field, and the Retransmission index field such that the set of time and frequency resources determined for PSSCH according to Clause 14.1.1.4C is in accordance with the PSSCH resource allocation indicated by the configured sidelink grant.
– the UE shall set the Resource reservation field according to table 14.2.1-2 based on indicated value X, where X is equal to the Resource reservation interval provided by higher layers divided by 100.
– Each transmission of SCI format 1 is transmitted in one subframe and two physical resource blocks per slot of the subframe.
– The UE shall randomly select the cyclic shift 
among {0, 3, 6, 9} in each PSCCH transmission.
Table 14.2.1-1: Mapping of DCI format 5A offset field to indicated value m
|
SL index field in DCI format 5A |
Indicated value m |
|
’00’ |
0 |
|
’01’ |
1 |
|
’10’ |
2 |
|
’11’ |
3 |
Table 14.2.1-2: Determination of the Resource reservation field in SCI format 1
|
Resource reservation field in SCI format 1 |
Indicated value X |
Condition |
|
‘0001’, ‘0010’, …, ‘1010’ |
Decimal equivalent of the field |
The higher layer decides to keep the resource for the transmission of the next transport block and the value X meets |
|
‘1011’ |
0.5 |
The higher layer decides to keep the resource for the transmission of the next transport block and the value X is 0.5. |
|
‘1100’ |
0.2 |
The higher layer decides to keep the resource for the transmission of the next transport block and the value X is 0.2. |
|
‘0000’ |
0 |
The higher layer decides not to keep the resource for the transmission of the next transport block. |
|
‘1101’, ‘1110’, ‘1111’ |
Reserved |
.14.2.1.1 UE procedure for determining subframes and resource blocks for transmitting PSCCH for sidelink transmission mode 1
For 
,
– one transmission of the PSCCH is in resource block 
of subframe 
of the PSCCH period, where 
and 
.
– the other transmission of the PSCCH is in resource block 
of subframe 
of the PSCCH period, where 
and 
.
where
,
, 
and 
are described in Clause 14.2.3.
14.2.1.2 UE procedure for determining subframes and resource blocks for transmitting PSCCH for sidelink transmission mode 2
The allowed values for PSCCH resource selection are given by 0,1… 
where 
and 
described in Clause 14.2.3. The two subframes and the resource blocks are determined using selected resource value 
(described in [8]) and the procedure described in Clause 14.2.1.1.
14.2.1.3 UE procedure for PSCCH power control
For sidelink transmission mode 1 and PSCCH period i, the UE transmit power 
for PSCCH transmission is given by the following
– if the TPC command field in the configured sidelink grant (described in [8]) for PSCCH period i is set to 0
– 
– if the TPC command field in the configured sidelink grant (described in [8]) for PSCCH period i is set to 1
– 
[dBm]
where 
is defined in [6], and 
=1 and 
where
is defined in Clause 5.1.1.1. 
and 
are provided by higher layer parameters p0-r12 and alpha-r12, respectively and are associated with the corresponding PSCCH resource configuration.
For sidelink transmission mode 2, the UE transmit power 
for PSCCH transmission is given by
[dBm] ,
where 
is the 
configured by higher layers and 
=1 and 
where
is defined in Clause 5.1.1.1. 
and 
are provided by higher layer parameters p0-r12 and alpha-r12, respectively and are associated with the corresponding PSCCH resource configuration.
For sidelink transmission mode 3, the UE transmit power 
for PSCCH transmission is given by
[dBm],
where 
is defined in [6], 
is the bandwidth of the PSSCH resource assignment expressed in number of resource block, 
, and 
where
is defined in Clause 5.1.1.1. 
and 
are provided by higher layer parameters p0SL-V2V and alphaSL-V2V, respectively and that are associated with the corresponding PSSCH resource configuration.
For sidelink transmission mode 4, the UE transmit power 
for PSCCH transmission in subframe n is given by
[dBm],
where
is defined in [6], 
is the bandwidth of the PSSCH resource assignment expressed in number of resource block, 
, and 
where
is defined in Clause 5.1.1.1. 
and 
are provided by higher layer parameters p0SL-V2V and alphaSL-V2V, respectively and that are associated with the corresponding PSSCH resource configuration. If higher layer parameter maxTxpower is configured then
else
where
is set to a maxTxpower value based on the priority level of the PSSCH and the CBR range which includes the CBR measured in subframe n-4.