An improved feedback cancelling method for on-channel repeater

A feedback canceller model was built to cancel the feedback interference which caused by the coupling paths between the antennas of the transmitter and receiver in on-channel repeater. The normalized delay least square mean algorithm was presented to improve the capability of feedback canceller. The improved method could not only cancel echo signal in a low processing delay when relaying, but also get a fast convergence rate and better maladjustment performance. With this algorithm, on-channel repeater may be applied in many wireless broadcasting systems with different guard intervals. Simulation results show that, when the antenna isolation is lower than the gain of repeater, the improved feedback canceller could eliminate the multi-path echo signal to an allowable level, and it could increase the antenna isolation above 20dB.