Methods for implementing uplink channel access in elaa-based communication system

Abstract

The disclosure provides a method for assisting a UE to implement a UL channel access in a base station of an eLAA-based communication system. The method comprises determining a listen-before-talk (LBT) priority for the UE; and transmitting a first signaling indicating the determined LBT priority to the UE. An enhanced UL channel access mechanism is proposed by the disclosure. In this mechanism, the eNB can provide some assistance to facilitate UL access. Chances of multiple user multiplexing and spectrum efficiency in LAA UL can be improved by this solution.

1 . A method for assisting a User Equipment (UE) to implement an Uplink (UL) channel access in a base station of an eLAA-based communication system, comprising:
 determining a listen-before-talk (LBT) priority for the UE; and   transmitting a first signaling indicating the determined LBT priority to the UE.   
     
     
         2 . The method of  claim 1 , wherein determining a LBT priority for the UE further comprises:
 determining a set of UL channel access parameters according to predetermined factors; and   determining the LBT priority based on the set of UL channel access parameters.   
     
     
         3 . The method of  claim 1 , wherein the predetermined factors at least comprise one or more of:
 transmission duration of a UL transmission burst;   number of UEs scheduled in the UL transmission burst;   traffic types and interference situations of the scheduled UEs; and   eLAA TDD configuration information.   
     
     
         4 . The method of  claim 2 , wherein,
 a same set of UL channel access parameters is determined for all UEs; or   different sets of UL channel access parameters are determined for different UEs.   
     
     
         5 .- 7 . (canceled) 
     
     
         8 . A method for assisting a User Equipment (UE) to implement an Uplink (UL) channel access in a base station of an eLAA-based communication system, comprising:
 indicating to the UE an expected transmission duration scheduled for the UE in the UL transmission burst.   
     
     
         9 . The method of  claim 8 , wherein indicating to the UE an expected transmission duration scheduled for the UE in the UL transmission burst further comprises:
 dynamically or semi-statically indicating the expected transmission duration to the UE through a signaling; or   indicating the expected transmission duration to the UE through a UL scheduling grant.   
     
     
         10 . A method for implementing an Uplink (UL) channel access in a User Equipment (UE) of an eLAA-based communication system, comprising:
 receiving from a base station a first signaling, which indicates a listen-before-talk (LBT) priority determined by the base station for the UE or a portion of a set of UL channel access parameters determined by the base station for the UE.   
     
     
         11 . The method of  claim 10 , wherein,
 in case that the first signaling indicates the LBT priority, the UE performs a LBT operation using a set of UL channel access parameters corresponding to the LBT priority; and   in case that the first signaling indicates a portion of a set of UL channel access parameters, the UE determines other parameters in the set of UL channel access parameters and the LBT priority based on traffic type and the pre-stored relations between LBT priorities and UL channel access parameters, and performs a LBT operation using the set of UL channel access parameters.   
     
     
         12 . The method of  claim 11 , wherein the method further comprises:
 adjusting the LBT priority according to the traffic type.   
     
     
         13 . The method of  claim 11 , wherein the method further comprises:
 transmitting a second type of traffics only after all of a first type of traffics have been transmitted, wherein a LBT priority of the first type of traffics is not less than the LBT priority, and a LBT priority of the second type of traffics is lower than the LBT priority.   
     
     
         14 .- 17 . (canceled) 
     
     
         18 . A method for assisting a User Equipment (UE) to maintain a Contention Window Size (CWS) in a base station of an eLAA-based communication system, comprising:
 configuring a set of CWSs, wherein each CWS in the set of CWSs is corresponding to a different listen-before-talk (LBT) priority and the set of CWSs is applicable to all UEs; and   simultaneously updating CWSs of all LBT priorities based on a predetermined trigger mechanism.   
     
     
         19 . The method of  claim 18 , wherein simultaneously updating CWSs of all LBT priorities based on a predetermined trigger mechanism further comprises:
 updating CWSs of all LBT priorities based on a PUSCH decoding result in the first subframe of a last UL transmission burst; or   updating CWSs of all LBT priorities based on a PUSCH decoding result in the last valid subframe of a last UL transmission burst;   wherein the PUSCH decoding result is that by the UEs that implement LBT Category 4 operations in the last UL transmission burst.   
     
     
         20 . The method of  claim 18 , wherein simultaneously updating CWSs of all LBT priorities based on a predetermined trigger mechanism further comprises:
 updating CWSs of all LBT priorities based on the PUSCH decoding result in all subframes of a last UL transmission burst, wherein the PUSCH decoding result is that by all UEs that implement UL transmissions in the last UL transmission burst.   
     
     
         21 . The method of  claim 19 , wherein the PUSCH decoding result is a ratio of a number of incorrectly decoded PUSCHs to a number of correctly decoded PUSCHs; and
 wherein if the ratio is larger than a pre-defined threshold, the CWSs of all LBT priorities will be exponentially or linearly increased; and   wherein if the ratio is not larger than the pre-defined threshold, the CWSs of all LBT priorities are reset to respective minimum CWSs corresponding to respective LBT priorities.   
     
     
         22 . The method of  claim 18 , wherein the method further comprises:
 transmitting the updated CWSs or a backoff counter generated therefrom to the UE.   
     
     
         23 .- 30 . (canceled)