Scaling laws and techniques in decentralised processing of interfered Gaussian channels
The scaling laws of the achievable communication rates and the corresponding upper bounds of distributed reception in the presence of an interfering signal are investigated. The scheme includes one transmitter communicating to a remote destination via two relays, which forward messages to the remote destination through reliable links with finite capacities. The relays receive the transmission along with some unknown interference. We focus on three common settings for distributed reception, wherein the scaling laws of the capacity (the prelog as the power of the transmitter and the interference are taken to infinity) are completely characterized. It is shown in most cases that to overcome the interference, a definite amount of information about the interference needs to be forwarded along with the desired message, to the destination. The upper bounds results are derived using the cut-set along with a new bounding technique, which relies on multiletter expressions. The latter is demonstrated to be useful in a scenario where the cut-set upper bound happens to be strictly loose. The lower bound results are derived using random-coding arguments, wherein some interesting cases combining lattices are found to be beneficiary, and used to determine the scaling laws of the achievable rate. Copyright © 2011 John Wiley & Sons, Ltd.