Joint Estimation of Angle and Delay of Radio Wave Arrival under Multiplicative Noise Environment

We address the problem of joint estimation of angle and delay of radio wave arrival in a multipath mobile communication channel using knowledge of the transmitted pulse shape function [1-3]. Employing an array of sensors to sample the radio received signal, and subsequent array signal processing can provide the characterization of a high-rank channel in terms of the multipath angles of arrival and time delays [4]. An improved characterization of the channel can lead to better equalization process and effective transmit diversity [5]. Although several works have been reported in the literature for estimation of the high-rank channel parameters, we are not aware of any work that deals with the problem of estimation in a fading channel, which essentially leads to a multiplicative noise environment [6]. Indeed, it has been pointed out while developing the cumulant-based techniques for multiplicative noise environment that the technique is useless for the Rayleigh faded radio channels because the fourth-order cumulant of the received signal is identically zero in this case [7]. In the present work, we develop a unique technique for parameter estimation of a Rayleigh faded high-rank channel under the assumption of independent multipath rays [8]. Note that in [8], the problem considered is related to the low-rank channel model arising from local scattering around the mobile unit, and there is no distant scatterer / reflector present [4].