Transmitter precoder design to improve the performance of the MUSIC algorithm

•A new error bound for the MUSIC algorithm is derived by adopting transmit processing.•An optimal precoder is proposed for transmit processing to achieve the new bound.•A practical precoder design leveraging on feedback channel information is proposed.•Both precoder design schemes perform close and improve the performance of MUSIC.

Using the MUSIC (MUltiple SIgnal Classification) algorithm to estimate the angle-of-arrival (AoA), we derive a new asymptotic error variance bound when the transmitted signal can be pre-processed. We next propose a precoder design to achieve this bound. However, such an optimal precoder requires channel state information at the transmitter (CSIT) exclusive of the receiver array which cannot be separately estimated practically. A more feasible precoder design, which leverages on the feedback CSIT estimated at the receiver, is next proposed. Using the performance of the optimal precoder which achieves the bound asymptotically as a benchmark, the practical precoder design performs close to the optimal precoder even in the high-resolution scenario. Both precoder schemes exhibit performance improvement compared with the case when no precoder is used.