Novel estimation algorithm design for FIR model with time-varying channel

A novel estimation algorithm which assures stability of a discrete FIR system with time-varying dynamics is derived by using loop transformation and the small-gain theorem. The proposed estimation algorithm incorporates an internal model of unknown dynamics for the time-varying channel. The stability condition is given by designing the estimation algorithm based on the small-gain theorem instead of the passivity theorem. The effectiveness of the proposed algorithm in numerical simulation is validated by comparing it with the conventional LMS approach.