一种高效的OFDM比特功率分配算法

黄新林¹, 王钢¹, 马永奎¹, 张成文¹, 姜浩²

1.哈尔滨工业大学通信技术研究所;2.哈尔滨工业大学电子与信息工程学院



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.

关键词:  OFDM  比特功率分配  Hughes-Hartogs算法  计算复杂度

DOI：10.11918/j.issn.0367-6234.2010.09.007

分类号:TN919.3

基金项目:装备预研资助项目(51306020201);国家重点基础研究发展计划资助项目(2007CB310601);中国博士后科学基金资助项目(20080440897)



An efficient bit loading algorithm for OFDM system

HUANG Xin-lin¹, WANG Gang¹, MA Yong-kui¹, ZHANG Cheng-wen¹, JIANG Hao²

1.Communication Research Center,Harbin Institute of Technology,Harbin 150001,China;2.School of Electronics Information Engineering,Harbin Institute of Technology,Harbin 150001,China

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.

Key words:  OFDM  bit loading  Hughes-Hartogs algorithm  computational complexity