Extraction of a weak co-channel interfering communication signal using adaptive filtering

Abstract

Conventional separation techniques such as filters cannot be used in a scenario where a weak signal is embedded within a stronger signal in the same frequency band. An adaptive filter approach to recover a weak narrowband communication signal embedded in a strong wideband broadcast signal and additive noise is investigated by taking advantage of the known characteristics of the broadcast signal standard. The weak signal considered is a four–quadrature amplitude modulation (QAM) communication signal, and the stronger signal is a Digital Terrestrial Multimedia Broadcasting (DTMB) signal, which is the digital television standard for People’s Republic of China. The results show that, while the extraction of the weak signal is possible, the characteristics of the transmission channel must be very accurately estimated for the scheme to achieve a reasonable error rate.