有限字符集下采用空间调制的物理层网络编码方案

空间调制(Spatial Modulation)通过利用天线索引承载数据信息,可以提升复用增益,实现更高速传输。利用这一特性,可针对协同多址接入信道模型设计一种基于空间调制的物理层网络编码方案。在协同节点,将其中一个源信息映射成传统调制符号,而将另一个源信息映射到协同节点的天线序号上。在目的节点,通过最大似然检测,判决接收到的传统调制符号和发射天线序号,分别恢复两个源节点发送的信息。研究结果表明,由于两个源信息载体相互独立,基于空间调制的多址接入方案可以获得优于传统方案的容量区域。仿真结果表明,在高信噪比条件下,系统和速率近提高1倍,同时两路信息误码性能均较好。此外,考虑到实际系统中使用的并非理想的高斯信源,文中分析均基于有限字符集展开。

Spatial modulation based physical-layer network coding with finite alphabet

By exploiting the index of antenna as an additional dimension to convey part of the information bits, Spatial Mudulation (SM) improves multiplexing gain and realizes a higher data rate. Motivated by this observation, an SM-based physical-layer network coding scheme is investigated for cooperative multiple access channel. After receiving the two source signals, the cooperation node maps them into traditional modulation symbol and the index of antenna, respectively. At the destination node, both source messages can be recoverred by detecting the symbol and the antenna index. The analysis reveals that the SM-based multiple access scheme achieves a better capacity region than traditional scheme, because the source messages are conveyed on the independent dimension. The simulation results verify the validity of the propsed scheme from the perspective of capacity and symbol error probability. Moreover, finite alphabet inputs are considerred because Gaussian inputs can never be realized in a practical communication system.