Design of Synchronization in OFDMA/TDD based Wibro System

The issues of time and frequency synchronization in OFDM system are quite essential to preserve the orthogonality among subcarriers, not to produce ICI. This paper deals with the efficient design of time and frequency synchronization in 802.16e and WiBro system which uses preamble sequence. We present the implementation issues and proper algorithm of the synchronization blocks such as coarse and fine timing synchronization, and fractional and integer frequency offset compensation. A technique to mitigate the false alarms of frame timing acquisition is proposed, which is added to the verification process using the results of cell search. Also, we present the frequency offset compensation process that compensates separate estimation result of fractional and integer frequency offset.