分布式Alamouti空时码的信道容量分析  

Channel Capacity Analysis of Distributed Alamouti Space-Time Code

作　　者：种稚萌[1] 朱世华[1] 吕刚明[1] 

机构地区：[1]西安交通大学电子与信息工程学院,西安710049

出　　处：《西安交通大学学报》2007年第8期969-973,共5页Journal of Xi'an Jiaotong University

基　　金：国家自然科学基金资助项目(60372055);教育部高等学校博士学科点专项科研基金资助项目(20030698027)

摘　　要：针对分布式Alamouti空时码(DASTC)系统的信道容量求解问题,提出了一种求解DASTC系统的信道容量闭式解及其上界的方法.该方法根据DASTC系统利用多节点联合发送信息的特点,选择距离信源节点最近的空闲节点作为中继节点构建了DASTC系统的无线中继信道模型,采用网络信息论中的最大流最小割定理,将DASTC信道模型分为广播信道模型和多接入信道模型,通过计算得到基于译码转发协议和基于放大转发协议的DASTC系统在固定衰落信道以及随机衰落信道下的信道容量闭式解及其上界.该方法可有效分析采用不同协议时的DASTC系统的信道容量变化.仿真结果表明,与采用香农定理的直接传输系统的信道容量相比,在高信噪比时,利用该方法所得的基于译码转发协议的DASTC系统和基于放大转发协议的DASTC系统的信道容量分别提高了1 b/(s.Hz)和0.4 b/(s.Hz).Focusing on the solution of the channel capacity for distributed Alamouti space-time code （DASTC） system, a novel method to derive the upper bound and the closed-form solution of the channel capacity for DASTC is proposed. Choosing the idle node closest to source node as relay node and utilizing the characteristic of DASTC that multiple nodes transmit information cooperatively, the wireless relay channel model is established for DASTC system. Using the max-flow min-cut theorem in network information theory, this method divides the channel model of DASTC into broadcast channel model and multiple access channel model. Sequentially, the upper bound of channel capacity and the achievable channel capacity of DASTC under fixed fading channels and random fading channels are derived. The channel capacity of DASTC based on different protocols can be effectively analyzed. The simulation results show that the channel capacity of DASTC based on decode-and-forward protocol and the channel capacity of DASTC based on amplify-an＆forward protocol, which are obtained by the proposed method, are superior to Shannon channel capacity of the direct transmission, and are increased by 1 b/（s · Hz） and 0.4 b/（s · Hz） at high SNR, respectively.

关 键 词：信道容量 分布式空时码 中继 

分 类 号：TN929.5[电子电信—通信与信息系统]