Lbt parameters for uplink in unlicensed spectrum

Abstract

According to some embodiments, a method for use in a user equipment (UE) of managing a listen-before-talk (LBT) contention window size comprises transmitting a first burst of uplink subframes after a first LBT procedure performed using an LBT contention window size, and determining a reference subframe based on the first burst. The reference subframe is associated with a reference hybrid automatic repeat request (HARQ) process identifier. The method further comprises receiving scheduling for a second burst of uplink subframes. The scheduling comprises an associated HARQ process identifier and an associated new data indicator (NDI) for each subframe. When the UE determines the HARQ process identifier associated with at least one of the subframes of the second burst matches the reference HARQ process identifier, then if the associated NDI indicates new data, the method resets the LBT contention window size, else the method increments the LBT contention window size.

1 . A method for use in a user equipment (UE) of managing a listen-before-talk (LBT) contention window size, the method comprising:
 transmitting a first burst of uplink subframes after a first LBT procedure, the LBT procedure performed using an LBT contention window size;   determining a reference subframe based on the first burst of uplink subframes, the reference subframe associated with a reference hybrid automatic repeat request (HARQ) process identifier;   receiving scheduling for a second burst of uplink subframes, the scheduling comprising, for each subframe of the second burst of uplink subframes, an associated HARQ process identifier and an associated new data indicator (NDI);   when the UE determines the HARQ process identifier associated with at least one of the subframes of the second burst of uplink subframes matches the reference HARQ process identifier and the associated NDI indicates new data, resetting the LBT contention window size to a minimum value;   when the UE determines the HARQ process identifier associated with at least one of the subframes of the second burst of uplink subframes matches the reference HARQ process identifier and the associated NDI indicates a retransmission, incrementing the LBT contention window size; and   performing a second LBT procedure using the contention window size.   
     
     
         2 . The method of  claim 1 , wherein determining the reference subframe comprises determining a most recently transmitted uplink subframe in the first burst of uplink subframes for which the associated HARQ process identifier is also found in the received scheduling for the second burst of uplink subframes. 
     
     
         3 . The method of  claim 1 , wherein determining the reference subframe comprises determining the first transmitted subframe of the first burst of uplink subframes for which the HARQ process identifier associated with the first subframe of the first burst of uplink subframes is also found in the received scheduling for the second burst of uplink subframes. 
     
     
         4 . The method of  claim 1 , wherein transmission of the first burst ended more than a threshold time prior to determining the reference subframe. 
     
     
         5 . The method of  claim 4 , wherein the threshold time is 4 ms. 
     
     
         6 . The method of  claim 1 , wherein resetting the LBT contention window size to a minimum value comprises resetting the LBT contention window size to a minimum value of a set of values associated with a priority class used by the UE to perform the first LBT procedure. 
     
     
         7 . The method of  claim 1 , wherein resetting the LBT contention window size to a minimum value comprises resetting LBT contention window sizes associated with all priority classes used by the UE. 
     
     
         8 . The method of  claim 1 , wherein incrementing the LBT contention window size comprises incrementing the LBT contention window size to a next value in a set of values associated with a priority class used by the UE to perform the first LBT procedure. 
     
     
         9 . The method of  claim 1 , wherein incrementing the LBT contention window size comprises incrementing LBT contention window sizes associated with all priority classes used by the UE. 
     
     
         10 . The method of  claim 1 , wherein the reference subframe is associated with a plurality of HARQ process identifiers and the LBT contention window size is incremented when the NDI associated with each HARQ process identifier of the plurality of HARQ identifiers indicates a retransmission. 
     
     
         11 . The method of  claim 1 , wherein the reference subframe is associated with a plurality of HARQ process identifiers and the LBT contention window size is reset when at least one NDI associated with a HARQ process identifier of the plurality of HARQ identifiers indicates new data. 
     
     
         12 . The method of  claim 1 , wherein performing the second LBT procedure comprises performing a Category 4 LBT for physical uplink shared channel (PUSCH) transmission on a licensed assisted access (LAA) secondary cell. 
     
     
         13 . A user equipment (UE) capable of managing a listen-before-talk (LBT) contention window size, the UE comprising processing circuitry operable to:
 transmit a first burst of uplink subframes after a first LBT procedure, the LBT procedure performed using an LBT contention window size;   determine a reference subframe based on the first burst of uplink subframes, the reference subframe associated with a reference hybrid automatic repeat request (HARQ) process identifier;   receive scheduling for a second burst of uplink subframes, the scheduling comprising, for each subframe of the second burst of uplink subframes, an associated HARQ process identifier and an associated new data indicator (NDI);   when the UE determines the HARQ process identifier associated with at least one of the subframes of the second burst of uplink subframes matches the reference HARQ process identifier and the associated NDI indicates new data, reset the LBT contention window size to a minimum value;   when the UE determines the HARQ process identifier associated with at least one of the subframes of the second burst of uplink subframes matches the reference HARQ process identifier and the associated NDI indicates a retransmission, increment the LBT contention window size; and   perform a second LBT procedure using the contention window size.   
     
     
         14 . The UE of  claim 13 , wherein the processing circuitry is operable to determine the reference subframe by determining a most recently transmitted uplink subframe in the first burst of uplink subframes for which the associated HARQ process identifier is also found in the received scheduling for the second burst of uplink subframes. 
     
     
         15 . The UE of  claim 13 , wherein the processing circuitry is operable to determine the reference subframe by determining the first transmitted subframe of the first burst of uplink subframes for which the HARQ process identifier associated with the first subframe of the first burst of uplink subframes is also found in the received scheduling for the second burst of uplink subframes. 
     
     
         16 . The UE of  claim 14 , wherein transmission of the first burst ended more than a threshold time prior to determining the reference subframe. 
     
     
         17 . The UE of  claim 16 , wherein the threshold time is 4 ms. 
     
     
         18 . The UE of  claim 13 , wherein the processing circuitry is operable to reset the LBT contention window size to a minimum value by resetting the LBT contention window size to a minimum value of a set of values associated with a priority class used by the UE to perform the first LBT procedure. 
     
     
         19 . The UE of  claim 13 , wherein the processing circuitry is operable to reset the LBT contention window size to a minimum value by resetting LBT contention window sizes associated with all priority classes used by the UE. 
     
     
         20 . The UE of  claim 13 , wherein the processing circuitry is operable to increment the LBT contention window size by incrementing the LBT contention window size to a next value in a set of values associated with a priority class used by the UE to perform the first LBT procedure. 
     
     
         21 . The UE of  claim 13 , wherein the processing circuitry is operable to increment the LBT contention window size by incrementing LBT contention window sizes associated with all priority classes used by the UE. 
     
     
         22 . The UE of  claim 13 , wherein the reference subframe is associated with a plurality of HARQ process identifiers and the LBT contention window size is incremented when the NDI associated with each HARQ process identifier of the plurality of HARQ identifiers indicates a retransmission. 
     
     
         23 . The UE of  claim 13 , wherein the reference subframe is associated with a plurality of HARQ process identifiers and the LBT contention window size is reset when at least one NDI associated with a HARQ process identifier of the plurality of HARQ identifiers indicates new data. 
     
     
         24 . The UE of  claim 13 , wherein the processing circuitry is operable to perform the second LBT procedure by performing a Category 4 LBT for physical uplink shared channel (PUSCH) transmission on a licensed assisted access (LAA) secondary cell. 
     
     
         25 . A method for use in a network node of signaling listen-before-talk (LBT) parameters, the method comprising:
 receiving a first burst of uplink subframes from a user equipment (UE) after a first LBT procedure, each subframe of the first burst of uplink subframes associated with one or more transport blocks, and each transport block associated with a hybrid automatic repeat request (HARQ) process identifier;   determining a set of transport blocks in the first burst of uplink subframes that were not received successfully by the network node; and   before scheduling the UE with a second LBT procedure, scheduling the UE with a second burst of uplink frames using all the HARQ process identifiers associated with the transport blocks in the determined set of transport blocks.   
     
     
         26 . The method of  claim 25 , wherein determining the set of transport blocks in the first burst of uplink subframes that were not received successfully by the network node comprises:
 determining a reference subframe based on the last subframe before a received subframe in which at least one transport block was received successfully; and   wherein the set of transport blocks includes the transport blocks in the reference subframe that were not received successfully.   
     
     
         27 . A network node operable to signal listen-before-talk (LBT) parameters, the network node comprising processing circuitry operable to:
 receive a first burst of uplink subframes from a user equipment (UE) after a first LBT procedure, each subframe of the first burst of uplink subframes associated with one or more transport blocks, and each transport block associated with a hybrid automatic repeat request (HARQ) process identifier;   determine a set of transport blocks in the first burst of uplink subframes that were not received successfully by the network node; and   before scheduling the UE with a second LBT procedure, schedule the UE with a second burst of uplink frames using all the HARQ process identifiers associated with the transport blocks in the determined set of transport blocks.   
     
     
         28 . The network node of  claim 27 , wherein the processing circuitry operable to determine the set of transport blocks in the first burst of uplink subframes that were not received successfully by the network node is operable to:
 determine a reference subframe based on the last subframe before a received subframe in which at least one transport block was received successfully; and   wherein the set of transport blocks includes the transport blocks in the reference subframe that were not received successfully.   
     
     
         29 - 30 . (canceled)