摘要
随着城市轨道交通的快速发展,车地移动通信系统对数据传输时延和传输速率的要求更加苛刻,针对此问题,引入LTE-U技术以加大频谱带宽。考虑到LTE-U系统会与现有WLAN系统产生干扰,因此,通过定量分析系统满意度函数以确保免授权频段LTE和WLAN的整体性能;采用M/G/1排队模型对LTE和WLAN共存异构网络在免授权频段的时域行为进行建模,设计了基于ABS的无线帧结构,并提出由启发函数和资格迹改进的HQL(λ)时域资源分配算法,基站通过与无线通信环境持续交互计算得到ABS(Almost-Blank Subframes)的最佳比例分配,解决免授权频段上LTE-U和WLAN系统的干扰共存问题。仿真结果表明:改进后的算法具有更快的收敛速度,且相比Q-Learning(λ)、Q-Learning,HQL(λ)资源分配算法的系统传输速率分别提高12.8%和26.1%,相比Q-Learning(λ),系统平均传输时延提高27.2%。
With the rapid development of urban rail transit,vehicle-ground mobile communication systems have more stringent requirements for data transmission delay and transmission rate.In response to this problem,LTE-U technology is introduced to increase the spectrum bandwidth.In view of the interference of the LTE-U system with the existing WLAN system,the system satisfaction function is quantitatively analyzed to ensure the overall performance of LTE and WLAN in the unlicensed frequency band.The M/G/1 queuing model is used to model the time-domain behavior of LTE and WLAN coexisting heterogeneous networks in unlicensed frequency bands,a radio frame structure based on ABS is designed,and HQL(λ)improved by heuristic function and qualification trace is proposed.Then,the optimal proportional allocation of ABS(Almost-Blank Subframes)is obtained by the continuously interactive computing between the base station and the wireless communication environment,which solves the problem of interference coexistence between LTE-U and WLAN systems in unlicensed frequency bands.The simulation results show that the improved algorithm has faster convergence speed,and compared with Q-Learning(λ)and Q-Learning,the system transmission rate of HQL(λ)resource allocation algorithm is increased by 12.8%and 26.1%respectively;and compared with Q-Learning(λ),the system average transmission delay is increased by 27.2%.
作者
王朋雨
米根锁
王彦快
WANG Pengyu;MI Gensuo;WANG Yankuai(School of Automation and Electrical Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China;School of Railway Technology,Lanzhou Jiaotong University,Lanzhou 730099,China)
出处
《铁道标准设计》
北大核心
2023年第1期175-181,共7页
Railway Standard Design
基金
国家自然科学基金项目(61763025)
兰州交通大学青年科学研究基金项目(1200061027)。
