Hybrid Channel Access Mechanism Based on Coexistence Scenario of NR-Unlicensed  

作　　者：Zhening Zhang Jingyi Chen Mingyang Dong Yuehong Gao Jingjing Wang 

机构地区：[1]Beijing University of Posts and Telecommunications,Beijing 100876,China [2]Chongqing University of Posts and Telecommunications,Chongqing 400065,China [3]Tsinghua University,Beijing 100084,China

出　　处：《China Communications》2020年第1期49-62,共14页中国通信（英文版）

基　　金：the Project “Evaluation and verification of candidate solutions for international standardization of 5G” supported by National Science and Technology Major Project of the Ministry of Science and Technology (2018ZX03001024-006)

摘　　要：With the rapid development of 5G NR(New Radio),the explosive increment of traffic amount is calling the utilization of unlicensed band.3GPP has proposed LAA(Licensed Assisted Access)to use LTE in unlicensed band and pointed out that NR-U(NR-Unlicensed)can reuse most designs of it.However,the existing channel access mechanism of LAA is conservative under the coexistence scenario of NR-U,which leads to the waste of time resource.To address the problem this paper proposes a hybrid channel access mechanism to take advantage of the LBT(Listen-Before-Talk)mechanism of LAA when channel is quite busy and transmit directly with reduced power when it is relatively idle.The channel busy degree is judged by a series of periodically updated adaptive thresholds.System-level simulation verifies that under the coexistence scenario of NR-U the proposed mechanism can achieve higher UPT(User Perceived Throughput)and lower delay than other channel access mechanisms.With the rapid development of 5G NR(New Radio), the explosive increment of traffic amount is calling the utilization of unlicensed band. 3 GPP has proposed LAA(Licensed Assisted Access) to use LTE in unlicensed band and pointed out that NR-U(NR-Unlicensed) can reuse most designs of it. However, the existing channel access mechanism of LAA is conservative under the coexistence scenario of NR-U, which leads to the waste of time resource. To address the problem this paper proposes a hybrid channel access mechanism to take advantage of the LBT(Listen-Before-Talk) mechanism of LAA when channel is quite busy and transmit directly with reduced power when it is relatively idle. The channel busy degree is judged by a series of periodically updated adaptive thresholds. System-level simulation verifies that under the coexistence scenario of NR-U the proposed mechanism can achieve higher UPT(User Perceived Throughput) and lower delay than other channel access mechanisms.

关 键 词：NR-U channel access mechanism LBT power reduction 

分 类 号：TN929.5[电子电信—通信与信息系统]