Channel capacity of multi user TR-MIMO-UWB communications system

Ultra wideband (UWB) system using multi antennas and time reversal (TR) possesses capability of multiuser system. Each user with long channel response signature is exploited for multiple access problems. If UWB channels are independent, the multi antenna UWB system shows both capacity and diversity gain. However, due to correlation between antennas, the performance of system degrades. In this paper, the channel capacity of multi user multi antenna TR-UWB system and the difference between the impact of transmit correlation and that of receive correlation on the system are derived. Channel capacity of system is significantly improved when number of using antennas increases in a acceptable range of the correlation coefficient. If the correlation of antennas is considered, at high correlation, the capacity reduces up to 60% in comparison with capacity if without correlation.