Low-complexity successive interference cancelation and one/two-bit feedback transmit antenna shuffling for 4 × 4 quasi-orthogonal space-time block codes

In this paper, we introduce a new way of successive interference cancelation (SIC) and transmit antenna shuffling (TAS) for quasi-orthogonal space-time block codes (QO-STBC) with 4×4 block structure. To be more specific, with the proposed SIC, single-symbol decoding becomes possible. Importantly, we show that only simple scalar operations are required, which keeps the computation load for decoding at a very low level. An efficient one/two-bit feedback TAS scheme is also derived for QO-STBC employing the SIC. The resultant error-rate performance can then be further improved with limited increase in feedback redundancy. All these are attractive features for actual QO-STBC usage. Simulation results show that the bit-error rate (BER) of our proposed SIC can be very close to that of the conventional pair-wise maximum likelihood (ML) decoding. Besides, for the considered QO-STBC system, applying our SIC together with TAS can let the BER performance approach that of ideal four-path diversity with reasonable decoding complexity and feedback amount.