CDMA's dependence on good timing and related issues
C.E. Wheatley · 2002
This paper discusses how the performance of CDMA (Code Division Multiple Access) depends on having time and frequency references. The time references of all Base Stations, or Cells, in this cellular system are synchronized to UTC (GPS time scale), enabling mobile users without prior knowledge of time of day to acquire forward link short-code signals, identify the Cells and compare their relative signal strengths. The Mobiles then base their long-code transmissions on the time they receive these forward link signals, which in turn enables the Cells to rapidly acquire the reverse links, and offers some measure of user location. Time/Frequency references of the Cells are quality sources, while those of the mobile stations are just good enough. This allows for low cost, low power solutions to be used in the portable phones.