采用最大比率发射技术的天线选择系统性能研究

Performance Investigation of Antennas Selection Systems Using Maximum Ratio Transmission

Alamouti方案(ALS)是仅有满速率的正交空时分组码(STBC),通过天线选择技术和优化发射功率提高其性能。若发射端知道全部的系统信道状态信息(CSI),文章提出在发射端混合最大比率发射(MRT)分集技术和发射天线选择(TAS)技术。基于信道增益系数大小的Frobenius范数最大的天线选择准则,系统选择瞬时输出信噪比(SNR)最大的天线子集{NT,2;mr}工作。采用MRT对Alamouti编码的双天线发射功率进行优化分配。仿真结果表明:采用混合MRT和TAS两技术后,基于ALS的多天线系统的比特误码率(BER)性能和信道容量均得到了明显改善。这一结论对有充足CSI的通信系统用于克服信道影响和提高系统传输速率具有借鉴意义。

Alamouti scheme （ALS） with double transmit antennas is of an unique full rate orthogonal space-time block codes. Combining antennas selection and power optimization can enhance the ALS＇s performance. In the case of known entire channel state informations （CSI） , maximum ratio transmission （MRT） diversity and transmit antennas selection （TAS） are introduced at the transmitter. Maximal Frobenius norm depends on the instantaneous channel gain factor is adopted as an antennas selection criteria, in which an antenna subset {NT,2 ;mr} with the maximal instantaneous signal-to-noise ratio （SNR） is always operated on the interest system. The selected double transmit antennas power with Alamouti codes are allocated by the MRT technique. Simulation results show that the bit error rate （BER） and channel capacity on the resulting multiple antennas system with ALS all obtain obvious improvement after mixing together MRT and TAS. These conclusions indicate the communication systems can adopt adequately CSIs to combat channel influence and enhance data rate.