Congestion relief in downlink OFDMA cellular system using inter-cell relay

This paper proposes the concept of inter-cell relay for downlink orthogonal frequency division multiple access (OFDMA) cellular systems, which uses multi-hop to relay calls from overloaded cells to light-load neighboring cells. It is shown that when using inter-cell relay, the number of calls in the congestion cell can be significantly increased. The congestion cell is divided into two parts. One is called non-relay area (NRA), in which a call directly communicates with the base station (BS) of a congested cell. The other is called relay area (RA), in which a call communicates with the BS of a neighboring cell through a relay station (RS). The two parts have different user-call densities. By adjusting the densities of two parts, we will maximize the number of supported calls inside a congested cell. The results show the benefits gained from inter-cell relay in congestion relief, which can reduce cell congestion by fully utilizing the available resources in the neighboring cells.