| 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 each frame. The subbands in each set are selected from among N total subbands such that an OFDM symbol for the first TDM pilot contains at least Si identical pilot-1 sequences of length Li and an OFDM symbol for the second TDM pilot contains at least Sidentical pilot-2 sequences of length L, where L> L, S· L= N, and S· L= N. 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).
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