A Novel Inter-Carrier Interference Cancellation Scheme in Highly Mobile Environments

In the current multi-carrier communications, Orthogonal Frequency Division Multiplexing (OFDM) is widely considered as a leading technology. For mobile applications, however, the orthogonality between subcarriers is deteriorated by Doppler frequency shift, which will introduce serious subcarrier phase rotation in the received signals and degrade the system performance. Thus, a method of differential grouping weighted symmetry data-conjugate (DWSCC) have been previously presented to obtain a better inter-carrier interference (ICI) suppressing effect and Bit Error Rate (BER) performance with no loss of spectral efficiency. In this paper, a novel scheme applying a completely different method of subcarrier interactive mapping is put forward. By mapping two different symbols which are both conjugated or multiplied by a complex weighting factor onto a pair of symmetric subcarriers, the presented scheme can greatly reduce the influence of subcarriers phase rotation caused by Doppler frequency shift in highly mobile environments. Analysis and simulation results indicate that comparing with the DWSCC method, our formulated scheme can not only maintain the spectrum utilization with no loss, but also have the advantages of an improvement on reduction effect and BER performance as well as a lower computational complexity in highly mobile environments.