Beamforming with opportunistic relaying for wireless security
Beamforming with opportunistic relaying for wireless security
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DOI：
10.1049/iet-com.2013.0349
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发表时间：
2014-05
期刊：
影响因子：
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通讯作者：
Md. Zahurul I. Sarkar;T. Ratnarajah;Z. Ding
中科院分区：
文献类型：
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作者：
Md. Zahurul I. Sarkar;T. Ratnarajah;Z. Ding
作者提出了一种利用机会中继（即机会波束形成）的波束形成方案，以实现放大转发（AF）和解码转发（DF）策略下的无线安全。中继选择采用分布式定时器的方法来执行，其中所有中继使用它们的定时器来估计自己的瞬时信道增益，并根据自己的信道条件竞争接入无线介质。分析了机会波束形成方案在安全中断概率方面的性能，并将波束形成问题制定为半定规划问题及其优化框架。结果表明，在机会主义波束形成方案中，协作中继之间的竞争在目的地方向上提供了多样性优势，从而提高了保密率（即最小化安全中断概率），并遵守“机会主义”合作规则，优先考虑“最佳”可用中继，即使它们没有被选择传输而是选择协作侦听。具有 DF 策略的机会波束形成方案比具有多个 DF 中继的波束形成提高了保密率，而在 AF 策略的情况下，与机会中继、等功率多中继传输和单中继传输方案相比，它在保密率方面提供了显着提高。
The authors present a beamforming scheme with opportunistic relaying (namely opportunistic beamforming) for wireless security under amplify-and-forward (AF) and decode-and-forward (DF) strategies. The relay selection is performed using the method of distributed timers, where all the relays use their timers to estimate own instantaneous channel gains and compete to access the wireless medium according to their own channel conditions. The performance of opportunistic beamforming scheme in terms of secure outage probability is analysed and the beamforming problem as a semidefinite programming problem with its optimisation framework is formulated. The results show that, in an opportunistic beamforming scheme, competition among cooperative relays offers diversity benefits in the direction of destination that enhances secrecy rate (i.e. minimises secure outage probability) and adhere to the ‘opportunistic’ cooperation rule giving priority to the ‘best’ available relay even when they are not chosen to transmit but rather chosen to cooperatively listen. Opportunistic beamforming scheme with DF strategy enhances secrecy rate than the beamforming with multiple DF relays while in the case of AF strategy, it provides significant improvement in the secrecy rate compared to the opportunistic relaying, the equal-power multiple-relay transmission and the single-relay transmission schemes.