Progressive equalizer matrix calculation using QR decomposition in MIMO-OFDM systems

Multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) technology has become a promising solution in current wireless communication systems. However, the implementation of MIMO-OFDM systems imposes a heavy complexity burden of equalizer matrix calculation on the training symbols due to the strict processing delay requirement. This paper presents a progressive QRD based equalizer matrix calculation method, which can significantly reduce the computational complexity in the last training symbol by distributing the heavy equalizer matrix calculation over multiple training symbols. Our proposed method was verified in the IEEE 802.11ac systems which have tough latency constraint. For 4 × 4 antenna configurations, the computational complexity on the last training symbol can be reduced by up to 75% without any BER loss.