认知无线电系统中OFDM多用户资源分配算法

Multiuser OFDM resource allocation algorithm for cognitive radio

基于认知无线电技术特点和OFDM传输特性,提出一种OFDM多用户资源分配算法.认知无线电用户根据感知的资源状况,针对用户的带宽以及QOS等要求,通过对子载波和功率的分配使得整个信道容量达到最大.本算法引入“调度因子”来体现用户子载波分配过程中“比例公平”的原则,保障每个用户都能满足一定的通信要求;引入“衰减因子”和用户设备类型,在不干扰授权用户通信的前提下进行多用户之间分配子载波和功率.算法采用“二步法”,以降低计算复杂度,满足于认知无线电实时性要求.仿真结果表明所提算法相对于FDMA方案信道容量至少提高40%.

Based on the multiuser orthogonal frequency division multiplexing （MU-OFDM） technique and the characteristics of cognitive radio, a novel multiuser resource allocation algorithm is proposed. In this algorithm, the secondary users choose their subcarriers and powers to achieve their QOS requirements based on the knowledge of the channel detections. The maximal channel capability is achieved accordingly. A schedule parameter is introduced to fit the need of fairness between secondary users. Meanwhile a decline parameter and the terminal types are also considered during the subcarrier and power allocation, and the interference to the primary users is avoided. The algorithm is based on the two step method. As a result, calculations are reduced and the real time requirements are achieved. Simulation results indicate that our method can achieve about 40% performance improvement compared with FDMA in channel capability.