همگام سازی توام زمانی و فرکانسی در سیستم های مخابراتی بر پایه استاندارد IEEE 802.11

The growing demand for high-quality services together with the rapid increase in number of users have made the high data rate as one of the basic requirements of the next generation broadband wireless networks. One of the proposed solutions for this purpose is the Orthogonal Frequency Division Multiplexing (OFDM), which is used in various standards, such as IEEE 802.11. On the other hand, OFDM System’s performance is highly affected by carrier frequency offset and time offset. Therefore, one of the essential requirements of each OFDM receiver is its capability in performing accurate time and frequency synchronization. Hence, in this paper, a joint time and frequency synchronization method for communication systems based on IEEE 802.11 is proposed. As the IEEE 802.11 standard uses training sequence or preamble in its frame, synchronization methods employed in this standard should be based on using such training sequences. Then, based on different metrics and using computer simulations, the performance behavior of the proposed method in AWGN and multipath fading channels is evaluated and compared with various training-based synchronization methods. Simulation results verify desirable performance of the proposed method in practical scenarios.

کلیدواژه ها:

Carrier frequency offset ، training sequence ، symbol timing estimation ، pilot-based synchronization