Autonomous time synchronization among radio ports in wireless personal communications

In digital wireless access communications systems, a large number of radio ports are deployed to provide wide-area coverage. Achieving time synchronization among ports is beneficial to these systems, especially for systems providing access to the infrastructure networks such as local exchange networks. This leads to better cochannel interference management and easier control for automatic link transfer. This paper describes a practical “over-the-air” algorithm which is autonomously performed by individual ports and hierarchically controlled by the ports having the most reliable timing. This process involves only small overhead for demodulating special timing bits transmitted by other ports and adjusting timing accordingly. Computer simulations based on a time division multiple access (TDMA) system with port spacing of 2000-3000 feet and 500 kb/s transmission rate are used as an example to evaluate possible impacts on wireless access