Improved QR Aided Detection Under Channel Estimation Error Condition

For future generation wireless techniques, multiple input multiple output (MIMO) systems are gaining an increasing interest due to its higher capacity and diversity gain. MIMO systems provide a linear increase in the channel capacity with respect to the number of antennas. Through multiple transmit antennas, multiple information symbols can be transmitted simultaneously, however, the challenge is to detect these symbols reliably at the receiver end. In this paper, we consider the problem of symbol detection in MIMO systems and present an improved QR aided detector under channel estimation error conditions. The proposed improved QR (IQR) detector is based on the underlying concept of multiple feedback (MF) strategy where multiple constellation points are used in the decision feedback loop of successive interference cancellation (SIC) based MIMO detector. In the proposed work, the detection sequence is ordered based on the signal to noise ratio (SNR) and the threshold radius of MF condition is varied according to the estimation error in the channel. The performance of the proposed algorithm is simulated and compared for different estimation error conditions.