Interference canceling equalizer (ICE) for mobile radio communications

This paper proposes an adaptive interference canceling equalizer (ICE) that not only equalizes intersymbol interference (ISI), but also cancels co-channel interference (CCI) in the received signal in Rayleigh fading environments. ICE employs a novel detection scheme, the recursive least squares maximum likelihood sequence estimation (RLS-MLSE), which simultaneously estimates time varying channel parameters. Diversity reception is used to enhance the signal detection performance of ICE. A computer simulation of 40 kb/s QPSK mobile radio transmission demonstrates the possibility of system capacity improvement by ICE. Simulations of ICE with diversity are carried out under the conditions of a two-path Rayleigh frequency selective fading channel with 50 μsec delay, 40 Hz maximum Doppler frequency, and 15 dB average E_b/N₀. ICE for single CCI cancellation attains an average BER of 10^-2 under a carrier-to-interference ratio (CIR) of -14 dB. ICE with two independent CCI signals attains less than 1.5×10^-2 average BER for average CIR⩾-10 dB