Analytical tools for space-time codes over quasi-static fading channels

This paper investigates several upper bounds and their validity for a particular space-time concatenated coding scheme. The system under study is a serial concatenation of a trellis outer code to provide coding gain followed by a space-time block code to insure diversity. Of interest is the performance of the coding scheme over a quasi-static fading channel (QSFC). It is shown in this paper how the classical union bound is divergent for the QSFC and this makes it unsuitable for studying codes and building design criteria. A different upper bound based on Berlekamp´s tangential bound (TB) is derived and its suitability for the purpose of analyzing this concatenation scheme is explored. Finally a new upper bound is derived which results in a more stable alternative. The result is a remarkably simple yet very reliable upper bound for space-time coded systems. Simulation results from an example scheme are provided and show that the new bound does indeed give a useful upper bound on the true system performance