Bandwidth and Routing Optimization in Wireless Cellular Networks with Relays

Abstract—This paper aims to quantify the performance improvement due to the use of fixed relays in the uplink of a wireless cellular network. Consider an orthogonal frequency division multiplex (OFDM) based cellular network in which each cell consists of a base station, multiple mobile users, and a number of relays. The questions of which frequency tones each link should use, whether the mobile station should communicate directly to the base station or though a relay, and how much power should be allocated on each frequency tone, form a simultaneous routing, frequency planning, and power allocation problem. This paper presents a dual decomposition approach to this problem and illustrates that while the use of relays does not necessarily increase the total cell throughput, it significantly improves the minimum common rate achievable across all the mobile users. Thus, the main benefit for deploying relays is in the improvement in fairness, rather than the total throughput. I