Reduction of the Peak Interference to Carrier Ratio of OFDM Signals

In this paper, we provide a geometric interpretation of the Peak Interference to Carrier Ratio (PICR) of OFDM signals. Based on this interpretation, we propose a simple approach to reduce the sensitivity of OFMA system to carrier frequency offset (CFO). The main idea is to choose a well understood code and to rotate each coordinate of the code by a fixed phase shift such that the maximum inter-carrier interference (ICI) taken over all sub-carriers is minimized. This approach enjoys the twin benefits of interference reduction and error correction and is easy to implement in practice. Simulation results show that a reduction of 7 dB can freely be obtained.