Joint user association and resource allocation in UE-Relay assisted heterogeneous networks

Abstract

We propose a novel approach that aims at extending femtocell coverage by enabling nearby idle User Equipments (UEs) in the proximity of femtocells to serve as relays, called UE-Relays. The users that would nominally connect to macrocells are offloaded to femtocells via the coverage extension provided by the UE-Relays. The problem of determining the optimal subset of idle UEs to be enabled as UE-Relays and the user association to these relays is a non-trivial problem because it depends on the projected capacity of the relay access and backhaul.We formulate the user association as an optimization problem that maximizes the network-wide log utility of the user rates. Our simulation results corroborate our expectations: overlaying a femtocelltier with UE-Relays will increase the user throughput and the network throughput. In addition, we compare our approach with a MAX-SINR based user association, and evaluate the performance profiles at varying scenario settings. The proposed rate-based scheme outperforms the SINR-based cell selection, thus validating the idea that, in heterogeneous cellular networks, user association should be performed based on the load rather than relying merely on link quality indicators

Selection of relay UE with energy harvesting capabilities in public safety environment

“…Relays divide one high-power transmission in to two low-power transmissions to save energy of the UEs [6]. In [7], the authors have proposed scheme to extend femtocell coverage by using relay UE. In this relay UE assisted heterogeneous cellular network, idle UEs opportunistically offload from macrocell to femtocell.…”

Energy efficient user association and resource allocation in active array aided HetNets

“…The researches on user association in AAS enabled HetNets are limited and still in its infancy. A joint user association and resource allocation algorithm was proposed in [19] for minimising the total time required to satisfy the user traffic demands. The problem of joint link selection and resource allocation for EE maximisation was studied in [1].…”