Patent ID: 7925261
Filing Date: 2011-04-12
Classification: H04L

Abstract:
1. A method for resolving frequency errors in a wireless device transitioning from a first communication network to a second communication network, the method comprising: receiving a first channel from the second communication network, the first channel having at least one known characteristic; decoding the first channel for a prescribed period; determining an initial frequency error value based on the decoding of the first channel for the prescribed period; adjusting a digital frequency rotator used to decode a second channel received from the second communication network by an amount based on the determined initial frequency error value; continuously decoding the second channel using the digital frequency rotator adjusted based on the initial frequency error value; determining when a decoding failure of the second channel decoding occurs, and a received signal strength of the second channel crosses a predetermined signal strength threshold; and repeating decoding of the first channel for the prescribed period, determining a subsequent frequency error value, and adjusting the digital rotator based on the subsequent frequency error value when a decoding failure has occurred and the received signal strength has crossed the predetermined signal strength threshold; wherein the first channel is a frequency correction channel (FCCH) and second channel is a synchronization channel.