Relay Placement in Wireless Networks: A Study of the Underlying Tradeoffs

It is known that the achievable data rate per user can be increased when relays are deployed in wireless networks. However, the drawback of this solution is that some of the network\´s resources should be allocated to the relays. In this paper, we consider a two-tier network in which all users send or receive data in two hops. By applying vector quantization, we compute the relays\´ locations to improve network\´s average transmission rate. These locations are also computed analytically when the number of relays is less than six. Having determined the relays\´ locations, the network\´s average transmission rate is evaluated. Subsequently, we define the "neutrality-surface" such that the performance of any relay network operating below this surface is inferior to that of the same network without relays. Finally, we study the relative relaying gain for different network configurations.