一种自适应广义空间调制及其低复杂度算法
An Adaptive Modulation Algorithm with Low Complexity for Generalized Spatial Modulation

针对广义空间调制(GSM)算法不能充分地利用信道状态信息的缺陷,提出了一种适用于GSM系统的自适应调制算法(AGSM),该算法利用已知信道状态信息,通过最大化空间调制星座点的最小欧氏距离,实现天线组合和符号调制星座的联合优化。进一步提出了一种低复杂度AGSM算法(LA-GSM),通过减少可选符号调制星座数量,并在传统天线组合集合与剩余天线组合集合中分别自适应选择相同符号调制星座,实现较低复杂度的天线组合和符号调制星座的联合优化,同时兼顾系统空间分集增益。仿真结果表明:在相同系统频谱效率5 b/(s？Hz)和6根发射天线条件下,所提的AGSM和LA-GSM算法以一定的算法复杂度为代价,均获得了相比于传统GSM算法更低的误码率性能,特别是在较高信噪比时AGSM算法和LA-GSM算法的误码率分别近似为GSM算法误码率的1/10和1/3;同时,LA-GSM算法获得了低误码率性能与低算法复杂度的较好折中。
A new adaptive modulation algorithm for generalized spatial modulation (AGSM) is proposed to make full use of the channel state information. The algorithm realizes the joint optimization of antenna combinations and symbol modulation constellations by using the known channel state information and maximizing the minimum Euclidean distance of space？？modulation constellation points so that the system performance is improved. Furthermore, a low？？complexity AGSM algorithm (LA-GSM) is proposed to reduce the complexity of the joint optimization of antenna combinations and symbol modulation orders. The LA-GSM achieves a lower complexity and makes full use of the antenna combinations of GSM systems by reducing the number of available symbol modulation constellations and searching the identical symbol modulation constellations from the typical antenna combinations and remanent antenna combinations adaptively and respectively. Simulation results show that both the AGSM and the LA？？GSM achieve much lower BER performance than the GSM does at a cost of certain complexity under same system spectral efficiency 5 b/(s？Hz) and 6 transmit antennas. Especially, the AGSM’s BER and LA-GSM’s BER are 1/10 and 1/3 of GSM’s one, respectively, when the SNR is high. Moreover, the LA-GSM achieves a better trade？？off between lower BER performance and lower complexity