Multi-layer SISO coding for MIMO channels

A coding scheme for a MIMO channel, based on superposition of dithered orthogonal design space-time block codes, is presented, building on and extending recent work of Erez, Wornell and Trott. When used in conjunction with successive decoding, the MIMO channel is converted into a set of AWGN scalar channels, allowing for standard coding and decoding techniques to be employed. By superimposing multiple layers of orthogonal-design codes, the well known drawback of loss of degrees of freedom of the latter is alleviated. When used in a closed-loop mode, the scheme allows to approach the white-input capacity of a MIMO channel with limited feedback, i.e., with feedback of the eigenvalues of the channel matrix. When used in an open-loop mode, the scheme exhibits good performance in terms of the diversity-multiplexing tradeoff. Further, the computational complexity is linear in the transmission rate.