Linear Mimo Receivers vs. Tree Search Detection: A Performance Comparison Overview

Next generation wireless systems use a combination of large system bandwidths and multiple antennas (MIMO) to deliver very high data rate services. The efficient demodulation of MIMO signals at the receiver can be a challenging task. In this paper, we study the gains achievable by using capacity-approaching tree search MIMO detection algorithms, for differently parameterized OFDM system setups and channel scenarios. Our results indicate that the high amount of diversity typically available in broadband MIMO-OFDM systems together with the use of low rate channel coding allows achieving very good performance using even simple linear MMSE detection. In iterative receiver approaches, the combination of initial linear MMSE detection and subsequent soft interference cancellation performs within 1 - 2 dB of the respective performance bound. The complexity involved in tree search detection techniques provides benefits mainly in very low-diversity environments, or if high rate channel coding is used together with higher order modulation