Contention window adjustment for new radio unlicensed/sidelink

Abstract

Methods, systems, and devices for wireless communications are described. A transmitting device may perform a first transmission to one or more receiving devices, the first transmission associated with a transmission type. The transmitting device may determine a feedback response for the first transmission based on monitoring for feedback messages from the one or more receiving devices in response to the first transmission. The transmitting device may select a contention window size for performing one or more subsequent transmissions based at least in part on the feedback response and the transmission type. The transmitting device may perform the one or more subsequent transmissions in accordance with a clear channel assessment procedure using the selected contention window size.

What is claimed is: 
     
         1 . An apparatus for wireless communication at a transmitting device, comprising:
 one or more memories storing processor executable code; and   one or more processors coupled with the one or more memories and operable to execute the code to cause the apparatus to:
 perform a first transmission to one or more receiving devices, the first transmission comprising a sidelink transmission associated with a unicast transmission type; 
 determine a feedback response for the first transmission based on monitoring for feedback messages from the one or more receiving devices in response to the first transmission; 
 select a contention window size for performing one or more subsequent transmissions based at least in part on the feedback response and the unicast transmission type; and 
 perform the one or more subsequent transmissions in accordance with a clear channel assessment procedure using the contention window size, the one or more subsequent transmissions comprising subsequent sidelink transmissions. 
   
     
     
         2 . The apparatus of  claim 1 , wherein the one or more processors are further operable to execute the code to cause the apparatus to cause the apparatus to:
 determine that at least one acknowledgement feedback message was received; and   resetting, based at least in part on the at least one acknowledgement feedback message, the contention window size for performing the one or more subsequent transmissions.   
     
     
         3 . The apparatus of  claim 2 , wherein the contention window size is reset to a minimum value of the contention window size. 
     
     
         4 . The apparatus of  claim 2 , wherein the first transmission comprises physical sidelink shared channel (PSSCH) information and physical sidelink control channel (PSCCH) information, and wherein the at least one acknowledgement feedback message indicates successful decoding of the PSSCH information and the PSCCH information. 
     
     
         5 . The apparatus of  claim 1 , wherein the one or more processors are further operable to execute the code to cause the apparatus to cause the apparatus to:
 determine that no feedback messages were received or that a negative-acknowledgement feedback message was received; and   increase, based at least in part on the no feedback messages or the negative-acknowledgement feedback message, the contention window size for performing the one or more subsequent transmissions.   
     
     
         6 . The apparatus of  claim 5 , wherein increasing the contention window size comprises doubling the contention window size. 
     
     
         7 . The apparatus of  claim 1 , wherein, to perform the first transmission, the one or more processors are operable to execute the code to cause the apparatus to:
 perform the first transmission during a reference slot, wherein selecting the contention window size is based at least in part on the first transmission being performed during the reference slot.   
     
     
         8 . The apparatus of  claim 7 , wherein the reference slot is associated with a channel occupancy time of the transmitting device. 
     
     
         9 . The apparatus of  claim 1 , wherein the first transmission comprises physical sidelink shared channel (PSSCH) information and physical sidelink control channel (PSCCH) information, and wherein the feedback response is based at least in part on the PSSCH information. 
     
     
         10 . The apparatus of  claim 1 , wherein the one or more processors are further operable to execute the code to cause the apparatus to cause the apparatus to:
 determine that at least one feedback message was received; and   resetting, base at least in part on the at least one feedback message, the contention window size for performing the one or more subsequent transmissions.   
     
     
         11 . The apparatus of  claim 10 , wherein the at least one feedback message comprises at least one negative-acknowledgement feedback message, at least one acknowledgement feedback message, or both. 
     
     
         12 . The apparatus of  claim 1 , wherein the one or more processors are further operable to execute the code to cause the apparatus to cause the apparatus to:
 determine that no feedback messages were received; and   increasing, base at least in part on the no feedback messages, the contention window size for performing the one or more subsequent transmissions.   
     
     
         13 . A method for wireless communication at a transmitting device, comprising:
 performing a first transmission to one or more receiving devices, the first transmission comprising a sidelink transmission associated with a unicast transmission type;   determining a feedback response for the first transmission based on monitoring for feedback messages from the one or more receiving devices in response to the first transmission;   selecting a contention window size for performing one or more subsequent transmissions based at least in part on the feedback response and the unicast transmission type; and   performing the one or more subsequent transmissions in accordance with a clear channel assessment procedure using the contention window size, the one or more subsequent transmissions comprising subsequent sidelink transmissions.   
     
     
         14 . The method of  claim 13 , further comprising:
 determining that at least one acknowledgement feedback message was received; and   resetting, based at least in part on the at least one acknowledgement feedback message, the contention window size for performing the one or more subsequent transmissions.   
     
     
         15 . The method of  claim 14 , wherein the contention window size is reset to a minimum value of the contention window size. 
     
     
         16 . The method of  claim 14 , wherein the first transmission comprises physical sidelink shared channel (PSSCH) information and physical sidelink control channel (PSCCH) information, and wherein the at least one acknowledgement feedback message indicates successful decoding of the PSSCH information and the PSCCH information. 
     
     
         17 . The method of  claim 13 , further comprising:
 determining that no feedback messages were received or that a negative-acknowledgement feedback message was received; and   increasing, based at least in part on the no feedback messages or the negative-acknowledgement feedback message, the contention window size for performing the one or more subsequent transmissions.   
     
     
         18 . The method of  claim 13 , wherein performing the first transmission comprises:
 performing the first transmission during a reference slot, wherein selecting the contention window size is based at least in part on the first transmission being performed during the reference slot.   
     
     
         19 . The method of  claim 18 , wherein the reference slot is associated with a channel occupancy time of the transmitting device. 
     
     
         20 . The method of  claim 13 , wherein the first transmission comprises physical sidelink shared channel (PSSCH) information and physical sidelink control channel (PSCCH) information, and wherein the feedback response is based at least in part on the PSSCH information.