An adaptive LMS estimation for channel variant condition in real time communication

This paper presents the novel blind adaptive method to estimate the impulse response of a real time wireless communications channel. The channel is assumed to have varying environmental conditions. The system proposed uses knowledge of receiver decision quality to evaluate the LMS estimators to increase their robustness to hard decision errors and channel noise. A soft decision algorithm was proposed for the channel estimation, where the algorithm uses decision factor as a function of receiver soft decisions, and a function of decision error knowledge. The performance of the proposed blind adaptive algorithm is evaluated to their non-blind counterparts through simulations over free-space propagation.