Burst frame and frequency synchronization with a sandwich preamble

Preamble schemes with periodic signal repetitions are often used for synchronization purposes in transmission over dispersive media. We describe a sandamble, being a splitted repetition preamble with reduced training overhead, and compare its frame and frequency synchronization performance in burst transmission to the performance of a conventional repetition preamble like standardized for IEEE 802.11a or HiperLAN/2 wireless modems. Optimum frame position and frequency offset estimation from a sandamble structure is treated and the Cramér– Rao lower bound for frequency estimation is derived. Though the fundamental idea is independent from the specific modulation scheme, we show results for Orthogonal Frequency–Division Multiplexing (OFDM). Keywords—Synchronization, Repetition Preamble, OFDM