A new DOA estimation approach for QPSK Alamouti STBC using ICA techniqueâ€based PSO algorithm

摘要

Alamouti space time block code (STBC) has been a revolutionary technology in multiple-input multiple-output (MIMO) wireless communication since it provides full transmission diversity. To reduce a multi-path effect and a consumed power, the dynamic beam-forming technique should be used to enable antennas focusing on a particular area. The aim of this paper is how to reduce the computational complexities of independent component analysis (ICA) and speed up the algorithm used in estimating the direction of arrival (DOA) angles. First, we derive a simple formula to reduce the number of unknown DOA to be one only. Then, real-imaginary (Re-Im) decomposition for MIMO system is used to reduce the computational complexities of ICA algorithm. The novel criteria used in this paper is that the kurtosis measuring for the extracted source will be minimum at one of the unknown values of DOA angles. Finally, particle swarm optimization (PSO) will be used as an effective tool to locate the DOA angle positions that minimize the kurtosis measuring. Performance analysis of the proposed approach with QPSK Alamouti STBC in MIMO channel was implemented using MATLAB. The validated criterions for the new approach were first examined. Then, root-mean-square-error (RMSE) was employed to test the proposed approach at different SNR levels. The main parameters that influence on this approach were evaluated. It was found that superior performance could be obtained at increment DOA 10(0) when antenna spacing set to be lambda/2 using at least 10(3) snapshots. The important point observed during simulations was computational complexity (and latency) of the proposed approach was reduced to the minimum by employing Re-Im decomposition model and PSO algorithm. Consequently, this approach is very efficient for hardware implementations.