Relay-Interference Networks

Information transmission in a shared medium is one of the fundamental problems in wireless communication. In such situation a wireless channel is shared between several sources and receivers, and several information flow are competing for resources.  Here, a fundamental question is how to manage interference in a wireless network.

In this work, we study the relay-interference wireless network, in which two transmitters are attempting to communicate with two receivers, each interested in distinct transmitter messages. There are relay (helper) nodes to facilitate competing information flows over a wireless network. We examine this in the context of a deterministic wireless interaction model, which eliminates the channel noise and focuses on the signal interactions.  Using this model, we show that almost all the known schemes such as interference suppression, interference alignment and interference separation are necessary for relay-interference networks. In addition, we discover a new interference management technique, which we call interference neutralization, which allows for over-the-air interference removal, without the transmitters having complete access the interfering signals. We show that interference separation, suppression, and neutralization arise in a fundamental manner, since we show complete characterizations for special configurations of the relay-interference network.

Then, we generalize some of our result to Gaussian noisy wireless networks, where we can get grateful insight through the deterministic results to obtain an approximation (within constant gap) for the capacity region of such networks.  

This is the first work in the context of deterministic wireless multiple unicast networks, and the result is quit important in the sense that the new developed transmission technique is shown to be crucial in achieving the capacity region of such networks.

Relay-Interference Networks