Optimal pilot interval design for the dedicated pilot channel

Abstract

Channel estimation plays a critical role in wireless communication systems where it is necessary to acquire channel state to compensate the received user data. For dedicated pilot channel, the known pilot symbols are usually time multiplexed with the user data symbols. When the carrier frequency is fixed, the channel coherence time is related with the vehicle speed. Thus in order to evaluate the channel state at the user symbol positions correctly, the time duration between two neighboring symbols must be less than the aforementioned channel coherence time. Is it right that the nearer of the two pilot symbols, the better of the system BER performance? Considering linear interpolation channel estimation, optimal pilot interval design is studied in this paper. Combined the noise accumulation property of interpolation method with the channel coherence time, the optimal design rule is presented. Simulations about the channel estimation performance for the different pilot intervals are done in LAS/CDMA system over ITU-VA channel. The results prove that the proposed design rule is reasonable and the experiential value for the optimal pilot interval is also given from lots of the simulation results, which is helpful for the dedicated pilot channel design.