考虑整数比特率及公平性的认知无线电OFDMA功率分配算法

在基于正交频分多址(OFDMA)的认知无线电系统中，每个认知用户在实际中都是以整数比特进行传输，而以往的速率取整算法只考虑了单认知用户。针对这种情况，提出了一种新的速率取整算法，该算法在原有算法的基础上进行了改进，让每个子载波最多参与一次速率的调整，从而使其在应用于多认知用户时保证了速率取整时的公平性，同时总的传输比特率比原算法有了一定的提高。仿真结果表明，所提算法有效提高了各认知用户在速率取整时的公平性。

An OFDMA power allocation algorithm considering integer bit rate and fairness for cognitive radio networks

For orthogonal frequency division multiple access(OFDMA)-based cognitive radio systems, the transmission rate of every cognitive user must be an integer in practice, and the single cognitive user is only considered in previous rate rounding algorithm. According to this situation, a new rate rounding algorithm is proposed in this paper, and it is modified based on the previous algorithm. Every subcarrier rate is adjusted once at most, which ensures the fairness at the rate rounding between cognitive users, and the total bit rate is also improved. The simulation result shows that the fairness among cognitive users is improved effectively by the proposed algorithm.