Preamble and Pilot Design with Computationally Efficient Synchronization and Cell Search Algorithms in Cellular OFDM Systems

Abstract

A computationally efficient initial synchronization technique is introduced in cellular orthogonal frequency division multiplexing downlink systems, which includes symbol timing estimation, frequency offset estimation, frame synchronization, and cell search. Novel preamble and pilot structures are proposed and a simple three-step synchronization scheme is developed based on a variety of practical conditions such as low computational complexity, time-varying frequency selective fading, limited preamble length, low peak-to-average-power ratio, and noncoherent synchronization with no channel estimation. The proposed three-step synchronization is sequentially described as (1) joint timing and frequency synchronization, (2) frame synchronization and preamble pattern identification (ID), and (3) pilot group ID. Simulation results show that the proposed technique nicely works even at low signal-to- interference-and-noise ratio regions.