Effects on CDMA network performance due to degradation of GPS based synchronization

Abstract

GPS based synchronizers have long been relied upon by various communications networks for achieving synchronization among the network nodes. Cellular networks, particularly CDMA (IS-95/2000) cellular networks, actively employ GPS timing receivers for making their time critical decisions, particularly handoff. Operations and parameters which set the network quality of service (QoS) require that these synchronizers provide timing with high stability. Therefore, a disturbance free solution from such synchronizers is vital. However, as these synchronizers employ GPS timing receivers, communicate with GPS satellites over the air interface; these are inevitably vulnerable to RF interference. This interference disturbs the timing receiver's performance, degrading its solution. This paper appreciates this issue, identifies the problems caused and discusses in detail the performance degradations of CDMA cellular networks due to instability of timing signals from GPS.