Random Coding Bounds on Concatenated Space-Time Transmission over MIMO Multiple Access Systems

Abstract:
Union upper bound and error exponent (cutoff rate) expressions for transmission of block codes over MIMO multiple access (MA) channels are obtained in closed forms. A series of combinatorial codeword enumeration problems are solved under the assumption of transmission of random block codes. Obtained bounds are meaningful as performance prediction and design tools for future MIMO MA systems in which each user employs a turbo-like block code as the outer code to drive the space-time inner code. The assumption of random outer block codes facilitates a closed-form derivation of the bound at the expense of losing some accuracy. To see its usefulness as a bound, bounds are compared with extensive system simulation results of a practical multi-user detection (MUD) receiver. The practical MUD receiver employs a turbo-iterative detection and decoding scheme while the transmitter employs the low-density parity-check code as the outer code and the BLAST type space-time transmission scheme as the inner code. The random block coding bounds are shown to match quite well with the simulation results.