Carrier Frequency Offset Mitigation in OFDM Systems Using Efficient Tone Reservation

One of the major drawbacks of orthogonal frequency division multiplexing (OFDM) is sensitivity to carrier frequency offset (CFO) caused by a mismatch between the transmitter and receiver oscillators. CFO destroys the orthogonality of the subcarriers and introduces intercarrier interference (ICI), reducing the system performance. Previously, tone reservation (TR) was considered for reducing the peak interference-to-carrier ratio (PICR) and shown to provide significant PICR reduction. In this paper, we use submatrices of the inverse fast Fourier transform (IFFT) and fast Fourier transform (FFT) to reduce the number of variables in the optimization to efficiently compute the optimal tones. Performance results are presented which demonstrate that the proposed algorithm yields PICR performance similar to that with the previous TR technique.