水声OFDM通信系统中的最优子载波功率分配  

Optimum power allocation for underwater acoustic OFDM 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：《西北大学学报（自然科学版）》2012年第6期919-924,共6页Journal of Northwest University（Natural Science Edition）

基　　金：国家自然科学基金资助项目(51249005;60972153);教育部博士点基金资助项目(20106102120013;20096102110038);西北工业大学基础研究基金资助项目(NPU-FFR-JC201004)

摘　　要：目的研究水声OFDM通信系统中的最优子载波功率分配。方法提出了水声OFDM通信系统中的最优子载波功率分配算法。首先将传播损失等效到信道频域响应中,建立了水声OFDM等效传播模型。在此模型基础上,以最大化OFDM系统中的有效子载波数目为目标,根据各子载波上的星座图、误码率门限、传播损失和环境噪声,结合信道信息对各子载波上的功率进行最优分配。对信道已知和信道未知、近距离传输和远距离传输等不同情况分别进行了讨论。结果文中算法在有效子载波数目比、OFDM块平均误码率、所需发射功率等方面均优于传统功率分配算法。结论文中算法可在水声OFDM通信系统中实现最优子载波功率分配。Aim To investigate the power allocation for underwater acoustic （UWA） OFDM system. Methods Focusing on the characteristic of frequency-dependent transmission loss and ambient noise of UWA channel, the UWA OFDM model is derived. Based on the model, an optimum power allocation algorithm for UWA OFDM system aiming at maximizing valid OFDM subcarriers at required transmission rate and bit error rate （BER） of each sub- carrier is proposed. If the channel response is known, the transmission power should be allocated according to transmission loss and ambient noise of each subcarrier which are related to system parameters and marine environ- ment. If the channel is unknown, on the other hand, the allocated power of each subcarrier should be decided by channel response, constellation, BER threshold, transmission loss and ambient noise of each subcarrier. Two situa- tions, i. e. , short range and long range transmissions, are discussed respectively. Results Our algorithm is superi- or in terms of the valid number of OFDM subcarriers, average OFDM block BER and required transmission power to traditional algorithms, as demonstrated by simulations. Conclusion The proposed algorithm could be employed by UWA OFDM system.

关 键 词：水声通信 正交频分复用 功率分配 

分 类 号：TN929.3[电子电信—通信与信息系统]