Cognitive Access Policies under a Primary ARQ Process via Forward-Backward Interference Cancellation
Cognitive Access Policies under a Primary ARQ Process via Forward-Backward Interference Cancellation
复制标题
通过前向-后向干扰消除的主 ARQ 过程下的认知访问策略
DOI：
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复制
发表时间：
2013
影响因子：
16.4
通讯作者：
M. Zorzi
中科院分区：
文献类型：
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作者：
Nicolò Michelusi;P. Popovski;O. Simeone;M. Levorato;M. Zorzi
本文介绍了一种使用i型混合ARQ的认知辅助用户（SU）通过最大努力传输到具有现有主用户（PU）的频谱的新技术。该技术利用主ARQ协议在SU接收器（SUrx）上执行干扰消除（IC）。引入了两种协同工作的IC机制：前向IC，其中SUrx在解码PU消息后，在PU重新传输相同消息后（可能）取消其干扰，以提高SU吞吐量；后向集成电路，SUrx对先前由于PU严重干扰而解码失败的SU传输执行IC。设计二次访问策略，确定网络各状态下的二次访问概率，通过机会性地利用IC来最大化平均长期SU吞吐量，同时造成有限的平均长期PU吞吐量下降和SU功耗消耗。证明了最优策略规定了SU在SUrx知道PU消息的状态下优先访问，从而实现了IC。在PU消息未知的状态下，提供了一种算法来优化分配额外的辅助访问机会。数值结果显示，以评估所提出的技术提供的吞吐量增益。
This paper introduces a novel technique for access by a cognitive Secondary User (SU) using best-effort transmission to a spectrum with an incumbent Primary User (PU), which uses Type-I Hybrid ARQ. The technique leverages the primary ARQ protocol to perform Interference Cancellation (IC) at the SU receiver (SUrx). Two IC mechanisms that work in concert are introduced: Forward IC, where SUrx, after decoding the PU message, cancels its interference in the (possible) following PU retransmissions of the same message, to improve the SU throughput; Backward IC, where SUrx performs IC on previous SU transmissions, whose decoding failed due to severe PU interference. Secondary access policies are designed that determine the secondary access probability in each state of the network so as to maximize the average long-term SU throughput by opportunistically leveraging IC, while causing bounded average long-term PU throughput degradation and SU power expenditure. It is proved that the optimal policy prescribes that the SU prioritizes its access in the states where SUrx knows the PU message, thus enabling IC. An algorithm is provided to optimally allocate additional secondary access opportunities in the states where the PU message is unknown. Numerical results are shown to assess the throughput gain provided by the proposed techniques.