Coordinated Resource Allocation for Downlink Transmissions: The Intra-Site Case

The latest generation of wireless networks use OFDMA (Orthogonal Frequency Division Multiple Access) transmission technology in the downlink (e.g, WiMAX and LTE). The downlink is divided into bandwidth units and UEs (User Equipments) are each allocated a subset of these. Since at most one UE is assigned to each of these units, downlink transmissions within a sector are orthogonal. However, the transmission is affected by intersector interference since UEs in adjacent sectors may also have been assigned to the resource. If the transmissions in neighbouring sectors are strong then the intersector interference may severely limit the SINR achieved by the UE. In this paper we consider a single site consisting of multiple sectors and consider the problem of maximizing the downlink capacity. We show that the sum rate, of a single resource unit, is maximized using a binary power allocation strategy. We then provide numerical results for a simple example to illustrate the gains that can be potentially achieved.