OFDM移動受信におけるMMSE型ICIキャンセラに関する一検討

概要

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In OFDM transmission, a loss of sub-carrier orthogonality due to Doppler-spread channels leads to inter-carrier interference (ICI). This problem is especially severe in mobile reception environments. ICI causes significant degradation in bit error rate characteristics and its influence increases as the carrier frequency or velocity of the receiver increases. We propose a method to reduce ICI caused by the Doppler-spread channel. The transmission channel is modelled by a combination of multiple Doppler-shifted propagation paths and their parameters, such as attenuation, relative delay, and Doppler-shift, and are then estimated using scattered pilot symbols. The ICI is cancelled by multiplying the inverse matrix of the estimated channel matrix by the received OFDM symbol vector. However, the ICI canceller emphasizes a noise component, so it does not improve the bit error rate characteristics sufficiently. In this paper, we propose an ICI canceller based on MMSE that does not emphasize a noise component. Using computer simulation, we confirmed that ICI cancellers based on MMSE can reduce the bit error rate more than ICI cancellers based on zero-forcing under the Doppler-spread channel.
社団法人映像情報メディア学会の論文
2004-01-01