On the Capacity of Quasi Orthogonal Space-Time Block Codes for MIMO Systems
It is well known that the Alamouti scheme with two transmit antennas and one receive antennas is the only capacityachieving complex orthogonal space-time block code(OSTBC).The rate of complex OSTBC for systems with more than two transmit antennas is always less than 1. Recently, a quasi orthogonal space-time block code(QSTBC) with four transmit antennas and one receive antenna was proposed, which has the ability to approach the capacity, although at the price of sacrificing part of the diversity gain. In this paper, we analyze the capacity of QSTBC with four transmit antennas and arbitrary number of receive antennas. We show that the portion of the capacity that the QSTBC can achieve decreases with the number of receive antennas, and the (4,1) configuration is the only capacity-approaching case. In the high signal-to-noise ratio regime, we calculate the limit portion of capacity of QSTBC, and find that it is fixed to 1/4 when the number of receive antennas is no less than four. Numerical simulations verify our conclusions.
Yipeng LI Zhongfu YE
Institute of Statistical Signal Processing University of Science & Technology of China, Hefei, 230027, P.R.CHINA
国际会议
武汉
英文
65-68
2005-09-23（万方平台首次上网日期，不代表论文的发表时间）