MIMO detect-and-forward relay scheme using symbol LLR threshold

It is proposed here a way to improve the BER in a relay channel using maximum likelihood detection (MLD) over flat Rayleigh fading channels in a wireless Multiple Input-Multiple Output (MIMO) antenna system. The proposed relaying scheme uses the detect-and-forward protocol and consists of a new threshold mechanism based on symbol LLR at the relay. The relay determines whether each symbol can be relayed or not based on the error probability obtained from the received symbol LLR. The proposed relaying scheme over the conventional detect-and-forward presents the great improvement on Bit Error Rate (BER) for BPSK and QPSK modulations.