Resource allocation for OFDMA-based relay assisted two-tier femtocell networks

Co-channel interference (CCI) is a major issue faced by efficient co-channel deployed orthogonal frequency division multiple access (OFDMA) based two-tier femtocell systems. There are several resource allocation mechanisms proposed, such as, [1]-[4], to address this issue. However, none of these methods have considered employing relays in order to reduce transmit power levels, and hence, reduce CCI with the added advantage of extended coverage. Thus, in this paper, a simple resource allocation mechanism, which maximizes the sum of the weighted rates (SWR), for relay assisted femtocell systems is proposed. Its main advantage is the low complexity achieved by exploiting the characteristics of Lagrangian and utilizing the Newton´s method.