Low Complexity Decoders for Combined Space Time Block Coding and V-BLAST

Low complexity decoding schemes are presented for combined space time block coding and V-BLAST options in Enhanced Wireless Consortium draft for IEEE 802.11n. the authors exploit the structure of the transmitted data in developing the schemes. They are introduced for a frequency flat fading scenario and the diversity orders they yield are analyzed. The techniques are extended to orthogonal frequency division multiplexing mode of baseband modulation, and the impact of spatial correlation among the antennas is studied. Simulations are used to validate the predicted performance of the proposed schemes, predicted from the diversity order analysis. Also, their performance is compared with that of zero forcing successive interference cancellation (ZF-SIC). Computational complexities of the proposed as well as that of ZF-SIC are evaluated. The results show that one of the proposed schemes performs like ZF-SIC while its computational complexity is about one-half of that of ZF-SIC. Simulations with TGn channels, which are frequency selective channels and have spatial correlation, show that the performance degrades with increasing correlation.