Correlation Canceling-Type Feedback Canceler Based on Decision-Directed Pilot Symbols for T-DMB Repeaters

This paper presents a novel correlation canceling-type feedback canceler based on decision-directed pilot symbols for a terrestrial digital multimedia broadcasting (T-DMB) on-channel repeater (OCR). In order to guarantee an additional isolation of the OCR, two types of the feedback cancelers have been investigated: a correlation canceling (CC)-type feedback canceler and a frequency-domain channel estimation (FDCE)-type feedback canceler. While both of the feedback cancelers suppress the feedback signal effectively, they can operate complementarily each other with their own respective advantages. To achieve these complementary properties of the two types of feedback cancelers, we adopt a CC-type feedback canceling structure based on the frequency-domain estimated pilot symbols. The proposed feedback canceler improves the feedback channel estimation accuracy of the conventional CC-type feedback canceler as well as increases the channel estimation speed of the conventional FDCE-type feedback canceler. Simulation results show that the proposed feedback canceler has better feedback canceling performance and tracking ability for dynamic feedback channels.