电力线通信系统中跨层的用户调度和资源分配

User scheduling and resource allocation at cross-layer for power-line communications system

针对多用户多业务基于正交频分多址的电力线通信系统,提出一种在数据链路控制层进行用户调度和在物理层进行资源分配的多层多目标最优的跨层资源分配算法,其用户调度根据所有用户的服务质量(QoS)满意程度、QoS要求、业务包模型、信道状态信息和队列状态信息,从所有用户中选出要服务的用户和确定这些用户的最优跨层参数;其资源分配则根据所有调度用户的QoS要求、最优跨层参数和信道状态信息,先把功率按地窖注水原理分给每个子载波,再把每个子载波最优地分给调度用户并采用逐比特加载查表算法调整其上分配的功率和比特。最后在典型的电力线信道环境下对算法进行仿真,结果表明新算法在系统资源大范围变化时也能保障用户的服务质量,同时有效地提高系统资源的利用。

An optimal multi-layer multi-objective cross-layer resource allocation algorithm with user scheduling in data link control layer and resource allocation in physical layer was proposed for multi-user multi-service OFDMA （ Orthogonal Frequency Division Multiple Access） power-line communications systems. Firstly in the user scheduling, the scheduled users and their optimal cross-layer parameters were ascertained based on each user＇s current QoS, the desired QoS, traffic packet model, channel information and queue status. Secondly, in the resources allocation, according to all the scheduled users＇ desired QoS, optimal cross-layer parameters and channel state information, power was assigned to every subcarrier by cellar water-filling theory, then each subearrier to the scheduled users was optimally assigned and the allocated power and bits of each subcarrier were adjusted by bit-loading looking-up table algorithm. Finally in a typical power-line channel environment, the simulation results illustrate that the proposed algorithm can ensure users＇ QoS and effectively improve the resource utilization.