Hop timing recovery algorithms

Abstract

Communication systems must maintain tight timing synchronization between the transmitter and receiver. Systems typically pull-in timing from a large timing offset and then track timing once it has been sufficiently pulled in. When timing errors are large, additional reference symbols are needed to pull-in time. In some frequency hopping systems, the time pull-in step must be repeated for every hop and could occur many times a second. It then becomes important to develop rapid time pull-in algorithms that can operate on a limited number of data and reference symbols. This paper presents two algorithms for rapid time pull-in. The performance as a function of the number of data and reference symbols is shown.