Layered Frequency-Domain Turbo Equalization for Single Carrier Broadband MIMO Systems

A new layered frequency-domain turbo equalization (LFDTE) scheme is proposed for single carrier (SC) multiple-input multiple-output (MIMO) systems. The proposed scheme combines the respective advantages of layered detection and turbo equalization to further lower the bit error rate (BER) for high-data-rate communications. Different from the traditional frequency-domain turbo equalization (FDTE) method for MIMO systems, our new detection algorithm employs a layered structure in each turbo iteration, and at each layer a group of best data streams is detected in the form of soft symbols and then canceled from the received signals in frequency domain. The extrinsic information for the detected coded bits gleaned by the current layer is fed back to the previous layers as a-priori information utilized for equalization in the next iteration. Since the frequency-domain equalization (FDE) is performed in each frequency bin, the proposed receiver scheme has similar computational complexity compared to the traditional FDTE, but achieves better performance of BER. Simulation results demonstrate that the new proposed scheme outperforms the traditional FDTE without layered detection at the same number of iterations, and the performance becomes better if multiple layers are used in the detection.