Modified Alamouti decoding for highly selective channels for LTE systems

Abstract

In this contribution, we propose an improvement of Alamouti coding for equalization of space-time block code multiple-input multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM) over highly-selective fading channels for Long Term Evolution (LTE) systems. The conventional Alamouti STBC receiver suffers from performance degradation when the channel is not constant during the period of Alamouti codeword transmission. The principle of the new method is a modification of MIMO decoding at the receiver to adapt to the channel variations and improve consequently the link reliability of LTE system. Performance evaluation of the proposed method is confirmed by simulations and through a comparative study with well-known MIMO coding methods; the Vertical Bell-Labs layered Space Time Block code (VBLAST-STBC) and Golden Space-Time Trellis Code (Golden STTC). Also, performance evaluation, using estimated channels by the standard methods; Wiener estimator and Spline interpolator confirm that the modified Alamouti-based method can adapt to the channel variations and give a better channel equalization even over highly-selective fading estimated channels which subsequently improve the service quality and the link reliability.