Synchronization for RF carrier frequency hopped OFDM: analysis and simulation

Abstract

In this work, we apply RF carrier frequency hopping to orthogonal frequency division multiplexing (FH-OFDM) and study the hop rate capability using realistic performance of signal acquisition/synchronization of the unknown time and frequency offset parameters. OFDM synchronization is a challenging task without RF carrier hopping due to OFDM's sensitivity to time and frequency offsets. Given sufficient synchronization estimation performance is achieved, our objective is to determine the hop rate capabilities for OFDM using two different data-aided synchronization approaches. The first method is based on sending information in a preamble before the OFDM payload symbol. The second method embeds known synchronization information directly into the OFDM symbol stream. Using differential QPSK-OFDM modulation and spectral efficiency greater than 1 bps/Hz, results indicate that sufficient synchronization performance can be achieved for hop rates greater than 6 and 1 khops/sec for the preamble- and embedded-based synchronizers, respectively.