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.