Blind ML JADE in Multipath Environments Using Differential Evolution

In this paper, we tackle the problem of joint angles and time delays estimation (JADE) in a non-data aided (NDA) scenario where no pilot symbols are available at the receiver. A differential evolution (DE) technique is proposed in the context of maximum likelihood (ML) estimation is proposed to solve the resulting multi-dimensional optimization problem. DE is a metaheuristic global optimization algorithm-based on population, that finds the optimum iteratively by trying to improve a candidate solution based on an evolutionary process. We introduce the improved DE using a pseudo-pdf for easier generation of individuals. Simulations results show that the proposed solution is significantly more efficient in terms of global convergence than the classic differential evolution algorithm (CDEA) as well in terms of RMSE. Moreover, due to a very useful approximation, we are able to reduce even further the computational complexity of the proposed technique without any significant performance loss. Computer simulations also show the distinct advantage of the new NDA-DE approach over the existing techniques. Most remarkably, it also approaches the Cramér-Rao lower bound (CRLB) at medium and high SNR levels.