Linear computational complexity decoding for semi orthogonal full rate space time codes

Communication with low complexity decoding is an important attribute for many applications. From low cost, distributed sensors arrays with desirably long operative life to ultra smart handheld battery operated devices, low complexity decoding results in better power consumption and simpler hardware implementation. In this paper a linear decoding complexity is applied and analyzed to the semi-orthogonal space time codes which are rate 1 codes originated from a regular orthogonal space time codes. The proposed transmission and decoding schemes are very appealing in the sense that they improve the code rate of the orthogonal codes family, yet, maintain its simple, symbol by symbol decoding with no filter calculation complexity overhead. In addition, a performance boosting modifications are suggested and investigated for the basic transmission and decoding schemes under different system settings such as the availability of limited feedback and multiple receiving antennas.