M-QAM-OFDM水声通信系统的功率-速率联合分配算法  

A Joint Power Allocation and Bit Loading Algorithm for M-QAM-OFDM Underwater Acoustic Communication System

作　　者：姜喆[1] 王海燕[1] 赵瑞琴[1] 申晓红[1] 

机构地区：[1]西北工业大学航海学院,陕西西安710072

出　　处：《西北工业大学学报》2013年第5期753-757,共5页Journal of Northwestern Polytechnical University

基　　金：国家自然科学基金(60972153;51249005);教育部博士点基金(20106102120013;200961021100381);西北工业大学基础研究基金(NPU-FFR-JC201004)资助

摘　　要：研究了M-QAM-OFDM水声通信系统中的功率-速率联合分配算法。将传播损失等效到信道频域响应中,建立了综合大尺度与小尺度衰落的水声OFDM等效传播模型。水声通信由于信道环境恶劣一般使用低维调制,基于此特点和所建立的等效传播模型,研究了水声信道中的功率分配算法,通过水银注水算法使收发端的互信息达到最大。进一步考虑到实际通信系统中星座图一般为离散,通过功率-速率联合分配算法对通信系统的功率和速率进行联合分配,在发射功率一定及调制维数约束下使OFDM水声通信系统的传输速率达到最优。In this paper, we have proposed a joint power allocation and bit loading algorithm for underwater acoustic （UWA） OFDM system. We first derive the UWA OFDM model, which integrates both the large-scale and small-scale effects of UWA channel. Due to the poor quality of the UWA channel, most practical systems admit input signals from small finite discrete constellations. We then investigate the optimal power allocation to maximize the mutual information based on our model. Furthermore, a two-step joint power allocation and bit loading algorithm was proposed to maximize the transmission rate. Specifically, we resort to mercury/waterfilling algorithm to initially allocate the transmission power and bits among all subcarriers. Then all allocated power is rescaled to meet the pow- er and discrete constellation constraints.

关 键 词：水声通信 正交频分复用 正交振幅调制 功率分配 

分 类 号：TN929.3[电子电信—通信与信息系统]