A New Class of Precision UTC and Frequency Reference Using IS-95 CDMA Base Station Transmissions

This paper introduces a new class of precision timing and frequency reference that indirectly receives GPS timing and frequency information via the transmissions from Code Division Multiple Access CDMA mobile telecommunications base stations operating in compliance with Telecommunications Industry Association TINEIA StandQrd IS-95. Like cell phones, these products operate indoors without external antennas and provide unprecedented value to a large class of users in terms of accuracy, cost, and ease of installation. The technology fits particularly well in IP network synchronization and quality-of-service monitoring applications where rooftop antenna installation is often impossible. EndRun Technologies has developed and is manufacturing a proprietary time and frequency engine specifically optimized to faithfully reproduce the inherent precision time and frequency characteristics of the IS-95 CDMA sprea- spectrum signals. The Pracis family of time and frequency products uses this engine, and hundreds of these units have been deployed throughout North America since October of 2000. The salient characteristics of the IS-95 CDMA signals which make it so well suited to this use and a general receiver architecture are described. Performance data versus similar references that use conventional GPS reception are also presented.