Simplified weights update algorithm for semi-adaptive ordered successive detection in MIMO wireless systems

MIMO systems have attracted a lot of attention because of their higher spectral efficiency. However, one of the major limitations in MIMO systems is the complexity of the receiver that needs to separate multiple co-channel signals. In previous work, a semi-adaptive ordered successive detection scheme has been developed. In this paper, a simplification of the weights update algorithm from a MIMO-RLS (recursive least squares) to a modified MIMO-LMS (least mean squares) is introduced to this scheme. The new semi-adaptive receiver with proposed simplifications reduces the total complexity by a factor of almost 2M (M is the number of transmit antennas). This complexity reduction is achieved at the expense of only a slight performance penalty for slowly time-varying MIMO channels.