Rate 1 quasi orthogonal universal transmission and combining for MIMO systems achieving full diversity

This work addresses general multiple-input multiple-output systems and develops combined diversity transmission and combining schemes that achieve rate one and full diversity with reduced decoding complexity, while being universal in the sense that the operations performed at both transmission ends are channel independent. Such schemes may be useful in a scenario where a multiple-antenna source node communicates with the cloud via a multiple-antenna “dumb relay” that forwards the received vector over a rate-constrained digital front-haul link or serves as relay performing an amplify-forward operation over the air. The proposed schemes are derived by establishing an operational equivalence relation between the true channel and an associated multiple-input single-output channel.