Performance—Complexity Comparison of Receivers for a LTE MIMO–OFDM System

Implementation of receivers for spatial multiplexing multiple-input multiple-output (MIMO) orthogonal-frequency- division-multiplexing (OFDM) systems is considered. The linear minimum mean-square error (LMMSE) and the -best list sphere detector (LSD) are compared to the iterative successive interference cancellation (SIC) detector and the iterative -best LSD. The performance of the algorithms is evaluated in 3G long-term evolution (LTE) system. The SIC algorithm is found to perform worse than the -best LSD when the MIMO channels are highly correlated, while the performance difference diminishes when the correlation decreases. The receivers are designed for 22 and 4 4 antenna systems and three different modulation schemes. Complexity results for FPGA and ASIC implementations are found. A modification to the -best LSD which increases its detection rate is introduced. The ASIC receivers are designed to meet the decoding throughput requirements in LTE and the -best LSD is found to be the most complex receiver although it gives the best reliable data transmission throughput. The SIC receiver has the best performance-complexity tradeoff in the system but in the 4 4 case, the -best LSD is the most efficient. A receiver architecture which could be reconfigured to using a simple or a more complex detector as the channel conditions change would achieve the best performance while consuming the least amount of power in the receiver.