Systolic like soft-detection architecture for 4×4 64-QAM MIMO system

MIMO systems (with multiple transmit and receive antennas) are becoming increasingly popular, and many next-generation systems such as WiMAX, 3-GPP LTE and IEEE802.11n wireless LANs relay on the increased throughput of MIMO systems with up to four antennas at receiver and transmitter. High throughput implementation of the detection unit for MIMO systems is a significant challenge especially for higher order modulation schemes. To achieve superior Bit Error Rate (BER) or Frame Error Rate (FER) performance, the detector has to provide soft values to advanced Forward Error Correction (FEC) schemes like Turbo Codes. This paper presents a systolic soft detector architecture for high dimensional (eg. 4times4, 64-QAM) MIMO systems. A Single detector core achieves, throughput of 215 Mbps and power consumption of 23.6 mW, whiles using only 33.1 K gate equivalent (for l² norm). Impressive SNR gains of almost 2 dB are observed with respect to the hard detection counterpart over a block fading channel (at an FER of 1%). Additionally, the architecture can be stacked to give linear increase in throughput with linear increase in hardware resources.