Effect of channel estimation error on packet-based multi-user OFDM systems

Abstract

In this paper, we consider the performance of a packetbased multi-user orthogonal frequency division multiplexing (OFDM) wireless system in the presence of channel estimation error. To investigate the effect of incorrect channel information on the system performance, we consider the use of two channel estimation schemes; one is a simple linear and the other is an optimum Wiener-type channel estimator. We analyze the effect of channel impulse response (CIR) estimation error on coherent reception and the effect of instantaneous signal to interference and noise ratio (SINR) estimation error on channel aware techniques associated with packet scheduling. It is shown that the performance of coherent reception is relatively less susceptible to the CIR error, but the performance of channel aware schemes can be very sensitive to the SINR estimation error, mainly due to incorrect scheduling. To alleviate this scheduling problem, we propose an improved scheduling method which can be employed even with the use of a simple channel estimator. Finally, we verify the performance of the proposed scheduling scheme by computer simulation.