Achievable rate regions for many-to-one Gaussian interference channel with a fusion centre

This paper considers a many-to-one Gaussian interference channel with a fusion centre (FC) where there is a K-user interference channel in which only one relay (receiver) faces interference while the remaining K-1 receivers are interference free. All the relays communicate information about their observed sequence to the FC through noiseless links at communication rate R₀. First, by analysing traditional relaying schemes, i.e., Decode and Forward, Compress and Forward and Compute and Forward, three rate-regions for this setting are derived. Then, based on nested lattice codes, a new achievable rate-region is provided. Based on the proposed scheme, one can design a transmission scheme that can recover both integer and non-integer linear combination of messages. Numerical examples show that if channel gains are integer, the proposed scheme performs similarly to the compute-and-forward scheme. In the case of non-integer channel gains, the proposed scheme outperforms other relaying schemes at high signal-to-noise ratios. Finally, it is shown that if the channel gains are larger than one and if the rate of each relay-to-FC link equals to the capacity of an AWGN channel, then the proposed scheme can achieve the capacity region in high SNR regime.