On Preamble Length of OFDM-WLAN

A preamble technique for synchronization and channel estimation introduces transmission delay and wastes capacity unavoidably due to the time loss before data transmission. In this paper, we optimize a complete iterative receiver algorithm for different preamble lengths and study the feasibility to reduce the preamble length in OFDM-WLAN. The results show that - as expected - the preamble technique with reduced length offers worse synchronization and channel estimation versus SNR. However they also show that the preamble can be reduced compared to current standards to a minimum of three short repeated preamble sequences providing higher throughput regardless of modulation schemes. This is of particular interest, if an OFDM-WLAN system has non-negligible amount of bursty traffic and operates at high SNR.