Comparison of carrier frequency offset estimation schemes based on APSSB and preamble in OFDMA in fading channel

Abstract

The paper proposes a novel estimation scheme of carrier frequency offset (CFO) based on Added Preamble Sequence Semi-Blind (APSSB) scheme. The proposed CFO estimator is based on APSSB OFDMA model in which Gold sequence is added to the output of IDFT modulator and exploited for CFO estimation at the receiver. CFO estimators based on APSSB scheme and preamble are compared by both SINR analysis and simulation. We propose that the APSSB scheme should be employed for fine frequency synchronization in OFDMA especially in delay- insensitive service. In this paper, we propose the APSSB OFDMA model in which APSSB sequence is added to the output of IFFT modulator. The APSSB sequence is exploited for CFO estimation by correlation detection with the local APSSB sequence at the receiver. Comparison of SINR is made between CFO estimation schemes based on APSSB and preamble. More accurate CFO estimation by APSSB scheme doesn't cause date rate decrease because data and APSSB sequence are transmitted simultaneously. Furthermore, CFO estimation of APSSB scheme is more accurate than preamble scheme when APSSB symbol number for CFO estimation is large enough to exceed the threshold. Furthermore, the estimation time of APSSB scheme is more flexible than preamble scheme. The APSSB scheme has the property of better accuracy as well as larger delay. We propose the APSSB scheme should be employed for fine frequency synchronization in delay- insensitive service.