Concatenation of space-time block codes and "turbo"-TCM

Abstract

For high data rate transmission over wireless fading channels space-time block codes provide the maximal possible diversity advantage for multiple transmit antenna systems with a very simple decoding algorithm. To achieve also a significant coding gain space-time block codes have to be concatenated with an outer code. We derive a symbol by symbol MAP decoding rule for space-time block codes. We describe two schemes for "turbo"-TCM which have been shown to achieve decoding results close to the Shannon limit in AWGN channels. These turbo-TCM schemes are concatenated to space-time block codes. The MAP decoding algorithm is described. We also discuss a feedback to the space-time block decoder. Significant coding gain in addition to the diversity advantage is shown to be achieved while the decoding complexity is mainly determined by the trellis complexity of the outer code.