Detection of a low power communication signal in the presence of a strong co-channel TV broadcast interference using Kalman filter

Abstract

This research focuses on the detection of a low power communication signal in the presence of a strong co-channel television broadcast interference signal. The presence of strong co-channel interference makes the recovery of the desired weak power signal impossible using conventional filtering techniques that are based on time and frequency characteristics of the signals. The second-generation digital video broadcasting terrestrial (DVB-T2) standard is employed as co-channel interference in an additive white Gaussian noise channel. The weak signal is assumed to have a considerably smaller bandwidth than the TV interference and negligible phase-shift due to multipath. By using two antennas at the receiver, channel diversity can be exploited, and the weak signal can be recovered using Kalman filter (KF), assuming the channels seen by the two antennas are independent and time-invariant. Moreover, the transmitted co-channel interference is modeled as the state of a dynamic system whose input is the signal received at one antenna and the output is the signal received at the second antenna. Within this framework, the state can be estimated by a KF. Channel estimation is performed using DVB-T2 pilots. Performance of the system is evaluated at different signal-to-noise ratio (SNR) and signal-to-interference ratio (SIR). Results show that the weak signal can be reconstructed with bit error ratio (BER) of 10-3 or less under most SNR and SIR conditions considered in the study.