14.1.5 UE procedure for determining resource block pool and subframe pool for sidelink transmission mode 3 and 4
36.2133GPPEvolved Universal Terrestrial Radio Access (E-UTRA)Physical layer proceduresRelease 17TS
The set of subframes that may belong to a PSSCH resource pool for sidelink transmission mode 3 or 4 is denoted by 
where
– 
,
– the subframe index is relative to subframe#0 of the radio frame corresponding to SFN 0 of the serving cell or DFN 0 (described in [11]),
– the set includes all the subframes except the following subframes,
– subframes in which SLSS resource is configured,
– downlink subframes and special subframes if the sidelink transmission occurs in a TDD cell,
– reserved subframes which are determined by the following steps:
1) the remaining subframes excluding 
and 
subframes from the set of all the subframes are denoted by 
arranged in increasing order of subframe index, where 
is the number of subframes in which SLSS resource is configured within 10240 subframes and 
is the number of downlink subframes and special subframes within 10240 subframes if the sidelink transmission occurs in a TDD cell.
2) a subframe 
belongs to the reserved subframes if 
where 
and 
. Here, 
the length of the bitmap is configured by higher layers.
– the subframes are arranged in increasing order of subframe index.
The UE determines the set of subframes assigned to a PSSCH resource pool as follows:
– A bitmap associated with the resource pool is used where 
the length of the bitmap is configured by higher layers.
– A subframe 
belongs to the subframe pool if 
where 
.
The UE determines the set of resource blocks assigned to a PSSCH resource pool as follows:
– The resource block pool consists of sub-channels where is given by higher layer parameter numSubchannel.
– The sub-channel m for 
consists of a set of 
contiguous resource blocks with the physical resource block number 
for 
where 
and 
are given by higher layer parameters startRBSubchannel and sizeSubchannel, respectively