基于OFDM协作中继的机会主义频谱共享协议及其最优资源分配

Opportunistic spectrum sharing protocol and optimal resource allocation based on OFDM cooperation relaying

提出了一种基于OFDM协作中继的机会主义频谱共享协议。当主用户信道不好,不能达到其要求速率时,如果认知用户能够协作帮助主用户达到其要求速率,则该认知用户就可以以协作的方式接入主用户的频谱。在该接入方式中,认知用户利用接入频谱中的一部分子载波放大转发主用户的信息,帮助主用户达到其要求速率。然后可以利用剩余的子载波发送自己的信息。对这种接入方式中的资源分配进行了分析,利用对偶算法,提出了一种以最大化认知用户速率,保证主用户速率达到要求速率为原则的最优资源分配算法。如果认知用户不能够协作帮助主用户达到要求速率,为了有效地利用频谱资源,认知用户以非协作的方式接入主用户的频谱,利用接入的全部频谱来发送自己的信息。仿真结果验证了所提频谱共享协议的有效性,同时说明了主用户和认知用户都能够从该协议中获得好处。

An opportunistic spectrum sharing protocol based on OFDM cooperation relaying was proposed. When the primary user experiences weak channel conditions, it could not achieve its target rate. If the cognitive user could help the primary user achieve its target rate, it accessed the spectrum of the primary user in the cooperation way. In this access way, the cognitive user used a fraction of the subcarriers to amplify-and-forward the signal of the primary user, to help the primary user achieve its target rate. And uses the remained subcarriers to transmit its own signal. The resource allocation was analyzed in this cooperation way. An optimal resource allocation algorithm based on dual method was proposed, which maximized the rate of the cognitive user while guaranteeing the primary user achieve its target rate. If the cognitive user could not help the primary user achieve its target rate, to make use the spectrum efficiently, the cognitive user accessed the spectrum of the primary user in the non-cooperation way, and uses the whole accessed spectrum to transmit its own signal. The simulation demonstrates the efficiency of the proposed spectrum sharing protocol as well as its benefit to both primary and cognitive user.