A simple transmit diversity technique for wireless communications-英文文献.pdf

IEEE JOURNAL ON SELECT AREAS IN COMMUNICATIONS, VOL. 16, NO. 8, OCTOBER 1998 1451 A Simple Transmit Diversity Technique for Wireless Communications Siavash M. Alamouti Abstract— This paper presents a simple two-branch trans- environment, however, may require up to 10 dB improvement mit diversity scheme. Using two transmit antennas and one in SNR. The improvement in SNR may not be achieved by receive antenna the scheme provides the same diversity order higher transmit power or additional bandwidth, as it is contrary as maximal-ratio receiver combining (MRRC) with one transmit antenna, and two receive antennas. It is also shown that the to the requirements of next generation systems. It is therefore scheme may easily be generalized to two transmit antennas and crucial to effectively combat or reduce the effect of fading at MMM receive antennas to provide a diversity order of 2MMM. The both the remote units and the base stations, without additional new scheme does not require any bandwidth expansion any power or any sacrifice in bandwidth. feedback from the receiver to the transmitter and its computation Theoretically, the most effective technique to mitigate mul- complexity is similar to MRRC. tipath fading in a wireless channel is transmitter power control. Index Terms—Antenna array processing, baseband processing, If channel conditions as experienced by the receiver on one diversity, estimation and detection, fade mitigation,