混合保护准则下基于NC-OFDM的认知无线电系统功率分配

Power Allocation with Hybrid Protection Criterion for NC-OFDM-based Cognitive Radio System

针对主用户采用OFDM通信体制,认知用户采用NC-OFDM通信体制,认知用户共享主用户授权频谱的工作场景,研究了认知无线电系统功率分配策略。提出依据主用户不同工作状态,采用不同的约束准则:对认知用户工作信道,引入功率泄漏干扰因子约束认知用户的发射功率,以限制对主用户工作信道的泄漏功率强度;对主用户工作信道,设置主用户速率损失上限,以确保主用户正常工作。功率分配算法以混合约束准则为基础,最大化认知无线电系统的传输速率。仿真结果表明,与干扰功率约束机制相比较,本算法能显著提升传输速率。

This paper investigated power allocation algorithms for NC-OFDM based cognitive radio system, which access the spectrum originally licensed to an OFDM primary system. According to transfer status of primary users, there will be different constraint strategies.A new criterion referred to power leakage interference factor is proposed to constraint leakage power to primary users in the cognitive users working channels meanwhile, on the primary users working channels, primary users are protected by keeping the interference introduced to primary users rate loss below a threshold. Power allocation algorithm maximizes the rate of the cognitive radio system based on the hybrid constraint strategies. Then the numerical result show that, compared with the conventional interference power constraint, the cognitive system can achieve a significant rate gain under the proposed constraint.