Relays in cellular systems are sensitive to interference. A good relay design will transmit in a way that avoids excess out-of-cell interference. This article proposes a two-step algorithm for relay design for the relay interference channel, which models a relay-based cellular system. The transmitters and relays are equipped with multiple antennas while the receivers are equipped with a single antenna. In the first step, we propose to apply existing single-hop strategies to design the transmission parameters of the transmitters. In the second step, we propose to modify the interference pricing approach to design the relays. Interference pricing is used to provide the relays with information on how interference impacts the end-to-end achievable rates. A new method is proposed to compute interference prices via an approximation of the end-to-end achievable rate to integrate information about the relationship of the parameters in the two hops to alleviate mismatch between the rates on two hops experienced by the direct application of prior algorithms, which are designed specifically for the single-hop interference channel. Simulations show that the proposed algorithm outperforms the other designs, including the naive approach of applying the single-hop interference pricing strategies on two hops.
['Kien T. Truong', 'Robert W. Heath']
A distributed algorithm using interference pricing for relay interference channels