SYNCHRONIZATION IN A BROADCAST OFDM SYSTEM USING TIME DIVISION MULTIPLEXED PILOTS

摘要

In an OFDM system, a transmitter broadcasts a first TDM pilot on a first set of subbands followed by a second TDM pilot on a second set of subbands in ea ch frame. The subbands in each set are selected from among N total subbands suc h that (1) an OFDM symbol for the first TDM pilot contains at least S1 identic al pilot-1 sequences of length L1 and (2) an OFDM symbol for the second TDM pil ot contains at least S2 identical pilot-2 sequences of length L2, where , , and . The transmitter may also broadcast an FDM pilot. A receiver processes the first TDM pilot to obtain frame timing (e.g., by performing correlation between different pilot-1 sequences) and further processes the second TDM pilot to obtain symbol timing (e.g., by detecting for the start of a channel impulse response estimate derived from the second TDM pilot).