An Efficient Uplink OFDMA Channel Estimation under High-Speed Mobile Environment

OFDMA (Orthogonal Frequency Division Multiple Access) was known extensively for operating in various mobile communication systems. In OFDMA system, there are two parts of communication link, uplink which the uplink OFDMA is considered in this paper, and downlink. In uplink OFDMA communication, all users send their information signals to base station at the same time. Each channel between user and base station requires to be estimated from the combined received signals at base station. From this reason, this paper proposes a channel estimation method for actual uplink OFDMA system which N points IFFT/FFT is larger than M data subcarriers (N>M) which can provide more accuracy for channel estimation. In the computer simulation results, the normalized mean square error (NMSE) performance is evaluated for the channel estimation accuracy under high-speed mobile environment. There is 12dB gain at 10(-1) of NMSE for the proposed method over the conventional method as shown in the result.