一种高效的OFDM比特功率分配算法

An efficient bit loading algorithm for OFDM system

摘要:

针对802.11a中的数字调制方式:BPSK,QPSK,16QAM,64QAM(星座图采用格雷码编码,每个子载波最多承载6比特),每次对?RT/6」个功率增量较小的子载波分配2bit.仿真结果表明:改进的比特功率分配算法与Hughes-Hartogs算法的比特功率分配结果一致,但是计算复杂度小于Hughes-Hartogs算法的50%,并随着传输速率或子载波数的增加而进一步降低.

Abstract:

We propose an efficient bit-loading algorithm to minimize the total power to transmit a target rate of a single user in OFDM communication systems.Considering the digital modulations exploited by 802.11a,which are BPSK,QPSK,16QAM and 64QAM(constellation using Gray code and each sub-carrier carrying a maximum of 6 bits),?RT /6」subcarriers which have litter power addition are allocated with 2 bits each time.The proposed bit loading algorithm is optimal and has the same performance as Hughes-Hartogs algorithm,but greatly reduces the computational complexity.Simulation results show that the proposed bit loading algorithm has the same bit allocation results as Hughes-Hartogs algorithm,but the computational complexity is less than 50% compared with that of Hughes-Hartogs algorithm.The computational complexity will be further reduced when the transmission rate or subcarriers number increases.