Constrained Group Decoder for Interference Channels

We provide a general overview of the recent development on the constrained group decoder (CGD) for interference channels.We first consider the CGD for a simple system of interference channels with no feedback from the receivers to the transmitters,where the transmitters employ fixed-rate channel codes and modulation schemes.We provide simulation results to show that, compared with the interference suppression scheme that maximizes the signal-to-interference-plus-noise ratio(SINR) at the receiver and the one that minimizes the interference leakage to the signal subspace (i.e., interference alignment),the group decoder offers an signal-to-noise ratio (SNR) gain of around $5$dBat the outage probability $3 imes10^{-2}$ and bit error rate (BER) $2 imes10^{-3}$.We then discuss the application of the CGD to more sophisticated systems that allow feedback from receivers to transmitters.More specifically, we review the recently developed practical coding schemes for the constrained partial group decoder (CPGD)and the group decoder for the multi-relay-assisted interference channels.Compared with the interference alignment approach, the group decoding paradigm not only provides substantial performance gains,but also eliminates the need of feeding back the channel state information of all users to the transmitters,thus significantly reducing the system signaling overhead.