基于效用优化的星地融合网络联合用户关联及资源块调度算法  

Utility Optimization-Based Joint User Association and Resource Allocation Algorithm for Integrated Satellite-Terrestrial Network

作　　者：柴蓉[1] 陈米铃 李锦红 CHAI Rong;CHEN Mi-ling;LI Jin-hong(School of Communications and Information Engineering,Chongqing University of Posts and Telecommunications,Chongqing 400065,China)

机构地区：[1]重庆邮电大学通信与信息工程学院,重庆400065

出　　处：《电子学报》2023年第12期3483-3495,共13页Acta Electronica Sinica

基　　金：国家自然科学基金(No.62271097,No.62001076)。

摘　　要：星地融合网络通过实现卫星网络与地面蜂窝网络的有机融合,可为用户提供灵活的网络接入服务,满足多场景用户应用需求.然而,卫星网络拓扑结构的动态变化、星地链路的复杂特性、多网和多用户资源调度粒度的显著差异性,以及资源共享模式的多样性,均对星地融合网络用户关联及资源调度问题带来困难及挑战.本文针对星地融合网络下行链路增强型移动宽带用户(Enhanced mobile broadband User,EU)及高可靠低延迟通信用户(ultra-Reliable and low latency communications User,RU)数据传输场景,研究用户关联及资源调度问题.在满足用户传输需求、网络可用资源、资源共享模式等约束条件下,将联合用户关联及资源块调度问题建模为系统效用函数最大化问题.由于该优化问题为强耦合问题,不易直接求解,本文将原优化问题分解功率分配子问题、用户关联及资源调度子问题.针对功率分配子问题,利用拉格朗日部分松弛法对离散变量进行连续化,进而将功率分配子问题转换为凸优化问题,采用拉格朗日对偶算法进行求解.基于得到的功率分配策略,本文提出一种启发式算法确定用户关联模式及资源块分配策略,在对蜂窝网络可用时频资源状态进行评估的基础上,分别针对时频资源充足及时频资源不充足的情况设计用户关联及资源块调度策略.针对时频资源充足情况,根据用户资源调度模式,分别定义RU及EU的时空资源调度粒度,进而针对采用正交频分多址接入(Orthogonal Frequency Division Multiple Access,OFDMA)模式的RU及EU,基于KM匹配算法优化确定时频资源块调度策略;进而,针对采用穿孔模式的RU与EU,提出一种基于贪婪算法的EU资源块重调度策略,以满足用户最小传输速率;针对占用相邻子信道的EU优化确定OFDMA模式及非正交多址接入(Non-Orthogonal Multiple Access,NOMA)模式,以实现效用函数的提升.针对蜂窝By organically integrating the satellite network with the terrestrial network,the integrated satellite-terrestrial networks can provide flexible network access services for users and meet the requirements of various application scenarios.However,the dynamic changes of satellite network topology,the complex characteristics of satellite-ground links,the significant difference of resource scheduling granularity between multi-network and multi-user and the diversity of resource sharing modes all pose great challenges to the data transmission in the integrated terrestrial-satellite network.The user association and resource scheduling problem is studied for the downlink data transmission scenario of the integrated terrestrialsatellite network which consists of enhanced mobile broadband user(EU)and ultra-reliable and low latency communications user(RU).The joint user association and resource allocation problem is modeled as the system utility function maximization problem under the constraints of user transmission requirements,network available resources and transmission limitations.The formulated optimization problem is a strong coupling problem,which is not easy to solve directly.Then,the original problem is transformed into two sub-problems,i.e.,power allocation sub-problem,user association and resource scheduling sub-problem.To tackle the power allocation sub-problem,Lagrange partial relaxation method is used to relax discrete variables into continuous ones,then new variables are introduced to decouple the previously defined variables,and simplified power distribution sub-problem is formulated,which is solved by Lagrange dual algorithm.Based on the obtained power allocation strategies,a heuristic algorithm is proposed to determine user association and resource block allocation strategy.Based on evaluating the available state of time-frequency resources in cellular network,user association and resource block scheduling strategies are designed respectively for the situation of sufficient time-frequency resource and in

关 键 词：星地融合网络 用户关联 资源调度 效用优化 业务需求 对偶算法 

分 类 号：TN927.23[电子电信—通信与信息系统]