Priority-Based Resource Allocation for Downlink OFDMA Systems Supporting RT and NRT Traffics

Efficient radio resource management is essential in Quality-of-Service (QoS) provisioning for wireless communication networks. In this paper, we propose a novel priority-based packet scheduling algorithm for downlink OFDMA systems. The proposed algorithm is designed to support heterogeneous applications consisting of both real-time (RT) and non-real-time (NRT) traffics with the objective to increase the spectrum efficiency while satisfying diverse QoS requirements. It tightly couples the subchannel allocation and packet scheduling together through an integrated cross-layer approach in which each packet is assigned a priority value based on both the instantaneous channel conditions as well as the QoS constraints. An efficient suboptimal heuristic algorithm is proposed to reduce the computational complexity with marginal performance degradation compared to the optimal solution. Simulation results show that the proposed algorithm can significantly improve the system performance in terms of high spectral efficiency and low outage probability compared to conventional packet scheduling algorithms, thus is very suitable for the downlink of current OFDMA systems.

宽带网络中业务模型的性能评价

文中介绍了异步传输模式中的四种业务模型:恒定比特率业务模型CBR、实时可变比特率业务模型rt-VBR和非实时可变比特率业务模型nrt-VBR、可用比特率业务模型ABR,其中详细分析并讨论了非实时的可变比特率和可用比特率两种业务模型,通过对这两种模型进行性能评价以阐明其基本特点。

Shapley值的LTE系统下行QoS感知资源调度

针对长期演进(Long Term Evolution,LTE)系统下行链路多用户业务传输过程中实时(Real-Time,RT)业务与非实时(Non-Real-Time,NRT)业务传输性能需求问题,提出一种基于合作博弈论Shapley值的信道资源初始控制方法。该方法在MAC(Media Access Control)层根据业务传输数据量大小来计算联盟边界贡献值,然后利用Shapley值来计算各业务占用的信道资源,再根据所分配的信道资源进行RB(Resource Block)调度。链路仿真表明,该方法在保证各业务时延与丢包率的基础上,提升了非实时业务的传输性能,在用户数量从5变化到50的条件下,对比DPVT-MLWDF(Delay Priority Virtual Token-Modified Largest Weighted Delay First)算法,非实时业务的吞吐量平均增加了38.05%,公平性提升了12.51%。实验结果表明,所提出的区分业务的信道资源控制方法在多用户业务条件下保证了实时业务传输性能,提升了非实时业务的吞吐量及公平性,明显优于对比算法。

非实时业务下认知网络的频谱共享

根据某种特定业务的QoS要求制定相应的频谱共享策略,可以在这种情况下提高系统的频谱利用率,增加用户平均收益。对非实时业务下的认知网络的频谱共享策略进行了研究,考虑各非授权用户业务量和信道质量对系统频谱效率的影响,提出了一种非实时业务专用的NRT-dedicate频谱共享算法。仿真结果表明,在非实时业务情况下,该算法可以获得比通用业务的频谱共享算法的频谱利用率。