Joint Maximum Likelihood Estimation of Angular and Time-Delay MIMO Propagation Parameters

In this paper we derive an estimator for the parameters of the concentrated (specular) propagation paths and of the distributed (diffuse) scattering component that are frequently observed in channel sounding measurements. We propose an iterative two step procedure alternating between the estimation of the parameters of the specular propagation paths and the parameters of the distributed scattering. For the distributed scattering, the estimator improves at first the estimates of the parameters of the exponential distribution in time-delay domain. Then, using the estimated time-delay parameters, the estimates of the parameters of the angular distributions are improved. The procedure is repeated and the parameters of specular and diffuse scattering components are refined, both in time-delay and angular domains