An new OSIC detection scheme for V-BLAST systems with QAM modulation

This paper presents an improved ordered successive interference cancellation (OSIC) detection scheme for V-BLAST systems with square/rectangular QAM modulation. It utilizes an equivalent real-valued vector expression of relationship between transmit signals and received signals, exploits the constellation's product-form structure and can eventually make the order in which components of the transmit signals vector are extracted more “optimal” in some sense, thereby offering an improved error probability as compared to the conventional scheme. In addition, an efficient projection algorithm is proposed to calculate nulling vectors in a simple recursive fashion, in order to avoid the vast increase of complexity due to the fact that the original complex N-dimensional data and M × N channel matrix are transformed into an real 2N-dimensional data and a real 2M×2N channel matrix respectively. Complexity analysis shows that the complexity increases by only 33% which is much lower than other algorithms, as compared to the conventional OSIC detection scheme.