增强许可辅助访问(eLAA)/MulteFire能够在免授权频谱上同时支持上行(Uplink,UL)下行(Downlink,DL)传输。在免授权频段上,eLAA/MulteFire采用LBT(Listen Before Talk,LBT)机制接入信道,但该机制并不能避免与隐藏节点之间的传输冲突,从而...增强许可辅助访问(eLAA)/MulteFire能够在免授权频谱上同时支持上行(Uplink,UL)下行(Downlink,DL)传输。在免授权频段上,eLAA/MulteFire采用LBT(Listen Before Talk,LBT)机制接入信道,但该机制并不能避免与隐藏节点之间的传输冲突,从而导致时延加长或WiFi丢包。合理灵活的帧配置将减少这种传输冲突,降低WiFi传输时延,提高信道的接入概率。本文提出一种基于Q学习(Q-learning,QL)的动态上下行帧配置(DFC)机制。在这个机制中,基站被视为一个智能体,并将吞吐时间和公平性的不同组合定义为智能体状态,不同帧配置定义为智能体行为。智能体基于获取到的临近基站的帧配置和WiFi的平均传输时长,学习得到最优的帧配置。仿真结果表明,提出的基于QL的帧配置方法在确定一定公平性的前提下,极大提高了免授权频段的信道接入概率和吞吐量,降低了传输时延。展开更多
Qual comm宣布,其子公司Qual comm Technologies,Inc.（QTI）和SK电讯首次利用授权频谱与非授权频谱进行了增强型授权辅助接入（eLAA）和授权辅助接入（LAA）OTA技术演示。通过聚合授权与非授权频谱,创造更宽的双向数据管道,eLAA技术能...Qual comm宣布,其子公司Qual comm Technologies,Inc.（QTI）和SK电讯首次利用授权频谱与非授权频谱进行了增强型授权辅助接入（eLAA）和授权辅助接入（LAA）OTA技术演示。通过聚合授权与非授权频谱,创造更宽的双向数据管道,eLAA技术能提高上行和下行链路的数据传输速度。eLAA是LAA的演进版本,LAA只能利用非授权频谱提高下行链路的数据传输速度。展开更多
The growth of the wireless and mobile communication data traffic has brought severe challenges to the present telecommu- nication systems. To meet the ever-increasing mobile traffic demand in the next 5th generation ...The growth of the wireless and mobile communication data traffic has brought severe challenges to the present telecommu- nication systems. To meet the ever-increasing mobile traffic demand in the next 5th generation （SG） communication systems, deploying 5G in the unlicensed spectrum （SG-U）, has been regarded as a promising technology. The Third Generation Partnership Project （3GPP） has specified the standardization of the Li- censed Assisted Access （LAA） and its extension enhanced LAA （eLAA）, to opportunistically transmit in the unlicensed spectrum. The LAA/eLAA systems share unlicensed spectrum resource with other networks, e.g., the Wi-Fi systems. In this article, we analyze the coexistence between the eLAA and the Wi-Fi systems in the unlicensed spectrum. We firstly establish the system model where the eLAA coexists with the Wi-Fi systems. Then, we theoretically derive and figure out the unfairness in the multi-channel occupancy rate between the eLAA and the Wi-Fi systems. After that, we propose a weight based channel selection method to improve the fairness of the coexistence. The numerical results demonstrate that by avoiding contentions and declining collisions, our method not only enhances the fairness, but also improves the overall unlicensed spectrum usage rate.展开更多
文摘增强许可辅助访问(eLAA)/MulteFire能够在免授权频谱上同时支持上行(Uplink,UL)下行(Downlink,DL)传输。在免授权频段上,eLAA/MulteFire采用LBT(Listen Before Talk,LBT)机制接入信道,但该机制并不能避免与隐藏节点之间的传输冲突,从而导致时延加长或WiFi丢包。合理灵活的帧配置将减少这种传输冲突,降低WiFi传输时延,提高信道的接入概率。本文提出一种基于Q学习(Q-learning,QL)的动态上下行帧配置(DFC)机制。在这个机制中,基站被视为一个智能体,并将吞吐时间和公平性的不同组合定义为智能体状态,不同帧配置定义为智能体行为。智能体基于获取到的临近基站的帧配置和WiFi的平均传输时长,学习得到最优的帧配置。仿真结果表明,提出的基于QL的帧配置方法在确定一定公平性的前提下,极大提高了免授权频段的信道接入概率和吞吐量,降低了传输时延。
文摘Qual comm宣布,其子公司Qual comm Technologies,Inc.（QTI）和SK电讯首次利用授权频谱与非授权频谱进行了增强型授权辅助接入（eLAA）和授权辅助接入（LAA）OTA技术演示。通过聚合授权与非授权频谱,创造更宽的双向数据管道,eLAA技术能提高上行和下行链路的数据传输速度。eLAA是LAA的演进版本,LAA只能利用非授权频谱提高下行链路的数据传输速度。
基金partly supported by the National Science and Technology Major Project(grant no.16510711600)the National Natural Science Foundation of China(grant no.61631013)partly supported by the National Natural Science Foundation of China(grant no.61401440)
文摘The growth of the wireless and mobile communication data traffic has brought severe challenges to the present telecommu- nication systems. To meet the ever-increasing mobile traffic demand in the next 5th generation （SG） communication systems, deploying 5G in the unlicensed spectrum （SG-U）, has been regarded as a promising technology. The Third Generation Partnership Project （3GPP） has specified the standardization of the Li- censed Assisted Access （LAA） and its extension enhanced LAA （eLAA）, to opportunistically transmit in the unlicensed spectrum. The LAA/eLAA systems share unlicensed spectrum resource with other networks, e.g., the Wi-Fi systems. In this article, we analyze the coexistence between the eLAA and the Wi-Fi systems in the unlicensed spectrum. We firstly establish the system model where the eLAA coexists with the Wi-Fi systems. Then, we theoretically derive and figure out the unfairness in the multi-channel occupancy rate between the eLAA and the Wi-Fi systems. After that, we propose a weight based channel selection method to improve the fairness of the coexistence. The numerical results demonstrate that by avoiding contentions and declining collisions, our method not only enhances the fairness, but also improves the overall unlicensed spectrum usage rate.
