Helpers for Cleaning Dirty Papers

Inhalt:
We consider communication over an additive white Gaussian noise (AWGN) channel with additive interference. In our setup the sender has no knowledge of the interference. However, there exists a helper that is power constrained and has non-causal knowledge of the interference. The helper and the sender do not cooperate. We show that if the helper power exceeds the sum of the signal power and the noise power then the sender can communicate at the rate that equals the capacity of the AWGN channel with no interference. Further, we show that in the limit of arbitrarily large interference power, our scheme achieves within 0.1 bit of the capacity of the channel.