Optimal pilot interval design for channel estimation

In the wireless communication system, interpolated pilot scheme is usually applied for the dedicated pilot channel. It means that the known pilot symbols are time multiplexed with data symbols at the regular intervals within the time duration of one frame. Whether the length of the pilot symbol interval will affect the performance of channel estimation and what is the optimal pilot interval? They are the main problems studied in this paper. Considering linear interpolation channel estimation, the pilot interval design will be investigated in LAS/CDMA system. Based on the channel coherence time and noise accumulation property, the optimal design rule for the pilot symbol interval is given. Simulations are done over the ITU-VA channel at different vehicle speeds, and 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 significative for the improvement of the system performance.