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对动态频谱接入中的多个频谱的选择问题进行了研究,综合考虑物理层频谱感知错误和信道衰落等不利影响,提出了一种基于概率预测的动态频谱接入策略.该策略基于交替更新过程的结论,能够在提高频谱利用率的前提下为认知网络中次用户选择可用度较好的信道.推导了该方法的时延性能理论分析结果,仿真结果表明,提出的算法与现有的随机频谱接入算法相比具有更好的时延性能. 相似文献
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To improve spectrum utilization and mini-mize interference to Primary User (PU), an adaptive spectrum decision method is proposed for Seconda-ry User (SU), while taking traffic load balancing and spectrum heterogeneity into consideration. Long-term statistics and current sensing results are integrated into the proposed decision method of spectrum access. Two decision methods, namely probability based and sensing based, are presented, compared and followed by performance analysis in terms of delay. For probability based spectrum deci-sion, Short-Time-Job-First (STJF) priority queuing discipline is employed to minimize average residual time and theoretical conclusion is derived in a novel way. For sensing based decision we treat the inter-rupted service of SU as newly incoming and re-de-cision process is initialized to find available spec-trum in a First-Available-First-Access (FAFA) fash-ion. Effect of sensing error in PHY layer is also an-alyzed in terms of extended average residual time. Simulation results show that, for relatively low arri-ving rate of SU traffic, the proposed spectrum deci-sion method yields at least a delay reduction of 39. 5% compared with non-adaptive method. The pro-posed spectrum decision can significantly improve delay performance even facing sensing errors, which cause performance degeneration to both PU and SU. 相似文献
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针对异构认知网络中频谱管理框架的频谱决策问题展开研究,综合考虑物理层频谱感知错误和无线信道衰落、主用户的多次打断带来的不利影响,提出了基于概率的和基于感知的具有负载均衡功能的频谱决策方法。对于基于概率的频谱决策方法,基于短时业务优先的调度策略采用动态规划方法给出了其平均等待时延的闭式解;对于基于感知的频谱决策方法,提出了允许其中断后可以重新搜索可用信道的决策方法,减少了等待主用户传输的时延,并在分析比较两者时延的基础上,提出了一种总体时延最优的频谱决策方法。此外,将认知网络的异构信道特性考虑分析框架中,理论分析较具一般性。仿真结果证实了方法的有效性。 相似文献
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