Novel Forward/Backward Signal Space for Coherent Signals DoA Estimation and its Real-time Experimental Validation

The direction of arrival (DoA) angles estimation of several narrowband RF sources in multipath environments is crucial in real-time applications. In this paper, a new DoA algorithm is presented to reduce the computational complexity of estimating the DoA's of highly correlated signals in pairs while maintaining estimation accuracy. The method proposed employs Cholesky decomposition in conjunction with a novel forward/backward operation (FBO) applied to the signal subspace matrix to de-correlate the incident coherent sources while most of the existing methods employ conventional pre-processing techniques to the covariance matrix. Employing FBO to the signal space matrix along with Cholesky decomposition results in significant reduction in the computation time and the complexity of hardware implementation. These advantages make the method proposed well-suited for applications such as in massive-MIMO systems as well as in enabling next generation wireless communication networks (beyond 5G and 6G). Simulation results using Root Mean Square Error (RMSE) and results from real-time implementation on a Software Defined Radio (SDR) testbed are used to validate the efficacy of the proposed method. Results show that the performance of the method proposed compares favorably with the Root-MUSIC method.