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An Efficient Adaptive Space Time Coding Scheme for MIMO-OFDM Systems

Within the framework of the Stingray Project, a Hiperman compatible MIMO system, three architectures with different rate-one Space-Time Codes (STC) are presented and their performance assessed. Viewing beam-forming and Alamouti as the two extreme cases of the trade-offs between performance/ complexity/feedback-requirements, an efficient scheme is proposed that reduces complexity and feedback requirements at the mild cost of performance, thus posing as a good compromise candidate between the aforementioned two extremes. All examined schemes are rate-adaptive, based on periodically transmitted channel-state information (CSI) back to the transmitter, and they all employ turbo coding as the outer channel code option.