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 IEEE 802.11a or HiperLAN/2 wireless modems. Optimum frame position and frequency offset estimation from a sandamble structure is treated and the Cramer-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)