Enhanced congestion control mechanism for sidelink
A wireless device may receive one or more configuration messages indicating a plurality of resource pools. The wireless device may further measure a plurality of channel busy ratios (CBRs) for the plurality of resource pools based on a CBR measurement window size. The wireless device may also compare the measured CBRs between resource pools by applying a weighting factor. In an embodiment, the weighting factor may be determined based on a relative size of each resource pool of the plurality of resource pools. The wireless device may further select a resource pool for a sidelink transmission among the plurality of resource pools based on the comparing and transmit one or more transport blocks based on a determined transmission parameter.
1 . A method comprising:
receiving, by a wireless device, one or more configuration messages indicating a plurality of resource pools;
measuring a plurality of channel busy ratios (CBRs) for the plurality of resource pools based on a CBR measurement window size;
comparing the measured CBRs between the plurality of resource pools by applying a weighting factor, wherein the weighting factor is determined based on a relative size of each of the plurality of resource pools;
selecting a resource pool for a sidelink transmission among the plurality of resource pools based on the comparing;
determining a transmission parameter based on a CBR associated with the selected resource pool, wherein the transmission parameter is further determined based on a filtered CBR, and wherein the filtered CBR is based on:
the CBR associated with the selected resource pool; and
an L3 filtering coefficient; and
transmitting, via one or more resources of the resource pool, one or more transport blocks based on the transmission parameter.
2 . The method of claim 1 , wherein the CBR measurement window size is determined based on a subcarrier spacing of a sidelink bandwidth part.
3 . The method of claim 1 , wherein each of the plurality of CBRs is measured as a portion of sub-channels in a resource pool whose sidelink received signal strength indicator (S-RSSI) measured by the wireless device exceeds a threshold sensed over the CBR measurement window.
4 . The method of claim 3 , wherein the S-RSSI is measured as a linear average of a total received power per OFDM symbol observed by the wireless device only in a sub-channel in OFDM symbols.
5 . The method of claim 1 , wherein the CBR is further based on:
a latest measurement of the plurality of CBRs; and
an old filtered measurement of the plurality of CBRs.
6 . The method of claim 1 , further comprising receiving, by the wireless device from a base station, at least one or more ranges of transmission parameters per a CBR measurement range, wherein:
the plurality of CBRs is divided into a plurality of CBR measurement ranges; and
a range of transmission parameters for each CBR measurement range is configured by the base station.
7 . The method of claim 1 , wherein the transmission parameter further comprises at least one of:
a modulation and coding scheme;
a transmission power;
a resource block size; or
a number of layers.
8 . The method of claim 1 , wherein the transmission parameter further comprises a number of retransmissions.
9 . The method of claim 1 , further comprising determining a time-domain layer 3 (L3) filtering coefficient based on the CBR measurement window size.
10 . The method of claim 1 , wherein the one or more configuration messages are received via at least one of:
a radio resource control signal; or
a system information block.
11 . A wireless device comprising:
one or more processors; and
a memory storing instructions that, when executed by the one or more processors, cause the wireless device to:
receive one or more configuration messages indicating a plurality of resource pools;
measure a plurality of channel busy ratios (CBRs) for the plurality of resource pools based on a CBR measurement window size;
compare the measured CBRs between the plurality of resource pools by applying a weighting factor, wherein the weighting factor is determined based on a relative size of each of the plurality of resource pools;
select a resource pool for a sidelink transmission among the plurality of resource pools based on the comparing;
determine a transmission parameter based on a CBR associated with the selected resource pool, wherein the transmission parameter is further determined based on a filtered CBR, and wherein the filtered CBR is based on:
the CBR associated with the selected resource pool; and
an L3 filtering coefficient; and
transmit, via one or more resources of the resource pool, one or more transport blocks based on the transmission parameter.
12 . The wireless device of claim 11 , wherein the CBR measurement window size is determined based on a subcarrier spacing of a sidelink bandwidth part.
13 . The wireless device of claim 11 , wherein each of the plurality of CBRs is measured as a portion of sub-channels in a resource pool whose sidelink received signal strength indicator (S-RSSI) measured by the wireless device exceeds a threshold sensed over the CBR measurement window.
14 . The wireless device of claim 13 , wherein the S-RSSI is measured as a linear average of a total received power per OFDM symbol observed by the wireless device only in a sub-channel in OFDM symbols.
15 . The wireless device of claim 11 , wherein the CBR is further based on:
a latest measurement of the plurality of CBRs; and
an old filtered measurement of the plurality of CBRs.
16 . The wireless device of claim 11 , wherein the instructions further cause the wireless device to receive, from a base station, at least one or more ranges of transmission parameters per a CBR measurement range, wherein:
the plurality of CBRs is divided into a plurality of CBR measurement ranges; and
a range of transmission parameters for each CBR measurement range is configured by the base station.
17 . The wireless device of claim 11 , wherein the transmission parameter further comprises at least one of:
a modulation and coding scheme;
a transmission power;
a resource block size; or
a number of layers.
18 . The wireless device of claim 11 , wherein the transmission parameter further comprises a number of retransmissions.
19 . The wireless device of claim 11 , wherein the instructions further cause the wireless device to determine a time-domain layer 3 (L3) filtering coefficient based on the CBR measurement window size.
20 . A non-transitory computer-readable medium comprising instructions that, when executed by one or more processors of a wireless device, cause the wireless device to:
receive one or more configuration messages indicating a plurality of resource pools;
measure a plurality of channel busy ratios (CBRs) for the plurality of resource pools based on a CBR measurement window size;
compare the measured CBRs between the plurality of resource pools by applying a weighting factor, wherein the weighting factor is determined based on a relative size of each of the plurality of resource pools;
select a resource pool for a sidelink transmission among the plurality of resource pools based on the comparing;
determine a transmission parameter based on a CBR associated with the selected resource pool, wherein the transmission parameter is further determined based on a filtered CBR, and wherein the filtered CBR is based on:
the CBR associated with the selected resource pool; and
an L3 filtering coefficient; and
transmit, via one or more resources of the resource pool, one or more transport blocks based on the transmission parameter.