Toward real-time, low-power, highly parallel decoding of the golden code in Mobile WiMAX base stations

The Golden Code (GC) is an optimal full-rate full-diversity STBC for 2 × 2 MIMO communication systems. It is incorporated as a STBC communication method in the IEEE 802.16e (WiMAX) standard. However, its high decoding complexity has prevented its implementation in practical systems. Optimal and suboptimal decoders with reduced complexity have been proposed recently and the best ones achieve a worst-case complexity of O(N²) and O(N^1S), where N is the underlying QAM constellation size. In this paper, the fast essentially ML decoder with complexity of O(N²) is implemented on a low-power highly parallel SIMD processor, the ClearSpeed CSX700. The SIMD architecture of the CSX700 achieves significant reduction in decoding latency. The implementation in this paper reveals the potential for realtime decoding of the GC with a power consumption that is less than 100 W. This CSX700 solution can find application in the software-defined radio (SDR) of a Mobile WiMAX base station (BS).