QoS区分的高速移动OFDMA系统无线资源分配

QoS-aware Radio Resource Allocation in High-speed Mobile OFDMA Systems

针对高速移动环境下多业务多用户正交频分多址(OFDMA)系统下行链路提出一种动态资源分配方案。针对具有不同时延要求的多种类型数据包的数据流,提出了一种考虑多种时延服务质量(QoS)要求的动态资源分配算法。通过应用排队论原理,将用户的时延要求转化为速率约束,结合多普勒频移产生的中断概率的约束,形成一个高速移动环境下考虑用户不同QoS要求的最优化问题。该优化问题为混合整数非线性规划,直接求解的复杂度非常高。为了解决原问题,提出了次优方法。仿真结果表明,在高速移动环境下,提出的方法在保障用户各种QoS时延要求的同时,有效地提高了系统的容量。

A dynamic resource allocation scheme was proposed for downlink transmission in multi-service multi-user OFDMA systems in high-speed mobile environments.Referring to a data stream inclusive of multiple types of data packets with different time delay requirements,the dynamic resource allocation approach consid-ering multiple QoS requirements of time delays was put forward.By applying the queueing theory and combi-ning the constraint of the outage probability incurred by Doppler shifts,the QoS requirement of time delays was transformed into the data rate constraint and thus an optimization problem to consider different QoS re-quirements for different users in high speed mobile environments was formulated.The optimization problem was of the feature of mixed integer nonlinear programming with prohibitive complexity so that a sub-optimiza-tion approach was suggested to solve the optimization problem.Simulation results show that the proposed method improves system throughput significantly and satisfies different QoS requirements of time delays as well in high speed mobile environments.