Dynamically Adaptive Bandwidth for Sub Carriers in OFDM Based Wireless Systems

In this article the performance of orthogonal frequency division multiplexing (OFDM) systems with dynamically adaptable sub carrier bandwidth to mitigate inter carrier interference (ICI) is compared against standard OFDM systems with fixed sub carrier bandwidth. In current OFDM system, the sub carrier bandwidth or sub carrier spacing is a fixed design parameter. This is not efficient since the optimum sub carrier bandwidth depends on ICI, which is a function of several parameters such as residual frequency offset, Doppler frequency spread, received signal strength and carrier frequency. Existing algorithms to combat ICI are very complex and sometimes reduce bandwidth efficiency. As an alternative approach, it is worth verifying the benefits of using adaptive bandwidth for sub carrier (ABS). A method for implementing the above scheme is given. Results show that this type of adaptive OFDM scheme has the potential to provide a significant improvement in performance over OFDM systems which use fixed sub carrier bandwidth.