Uplink OFDMA Channel Estimation with Frequency Domain Compensation in Sparse Channel

Abstract

In orthogonal frequency division multiplexing (OFDM) systems, the estimated channel impulse response (CIR) can be recovered by transforming the initial channel frequency response (CFR) to time domain. The CIR is preferred to be filtered before transforming to frequency domain and using as accurate CFR. In orthogonal frequency division multiplexing access (OFDMA) systems, subcarriers are allocated to different users to transmit data. Every user uses part of the whole OFDM subcarriers. If we still use the conventional transform domain scheme, the frequency leakage will be significant. To solve the leakage, we proposes a new scheme named as time domain filter and frequency domain compensation (TFFC) scheme. In this scheme, the filtered CFR vector is compensated in frequency domain. Simulation shows that this scheme improves the channel estimation significantly.