Low complexity method to estimate co-channel signals using an antenna array

The estimation of binary, co-channel digital signals in a mobile multipath time-varying environment has been developed. However, it is computationally expensive since it involves the singular value decomposition (SVD) of large matrices. In this paper, a low-complexity variant for the estimation of co-channel binary signals has been developed, which uses iterative least squares with projection (ILSP) and iterative least squares with enumeration (ILSE) directly on the received data. The variant developed here exploits the structure in the signal matrix to reduce the complexity required for estimation of the signals. It has been found that though the algorithm is suboptimal, the bit error rate (BER) performance is quite satisfactory, while the computational complexity is reduced to great extent.