Frequency reuse in chunk-based multi-cell OFDMA systems

In OFDMA systems, chunk-based resource allocation is an effective approach to reduce the complexity of resource allocation by grouping a number of adjacent subcarriers into a chunk and allocating resources chunk by chunk. In this paper, chunk-based resource allocation is investigated in a multi-cell environment. To improve the spectral efficiency in the multi-cell system, fractional frequency reuse (FFR) is also adopted in the chunk-based OFDMA system. After theoretically analyzing the spectral efficiency of the chunk-based OFDMA system with FFR, the optimal value of the radius ratio, which is the ratio of the radius of the central area to the radius of the cell, to achieve the optimum system performance is given by numerical simulations. Numerical results show that the average spectral efficiency increases with increasing the number of users in the system. However, the value of the radius ratio to achieve the largest spectral efficiency is not affected by the number of users or the number of subcarriers per chunk.