Flexible Design of Frequency Reuse Factor in OFDMA Cellular Networks

The OFDMA systems are emerging for future cellular networks. Creating multiple data channels, they can support the flexible frequency reuse factor (FRF). Although FRF 1 is the best choice in terms of cell throughput, it causes intercell interference at the cell boundary, thereby being unable to serve the whole cell area. Therefore it was proposed to use the FRF of greater than 3. In this paper, we develop a flexible FRF design mechanism that provides an intermediate value between 1 and 3 while the conventional schemes are dedicated to use some integer numbers only such as 3, 4, or 7. In our design, if the number of shared channels between any neighboring cells is given, we implement it simply according to a difference set. Simulation results show that a FRF of 7/4 achieves better throughput than FRF 3 and overcomes the intercell interference problem of FRF 1, so it can replace the conventional FRF such as 3. We expect that our new FRFs have the advantage in supporting smooth handoff because there are always some common channels between two neighboring cells.