Evaluation of BSC clock frequency drifts on HOSR: — A practical perspective

Hand over is one of the most important function of a cellular network. Hand success rate (HOSR) improvement is an important optimization activity of a GSM network (NW). Cellular operators adapt different approaches like locations area updates at cell boundaries and optimization of adjacencies, threshold parameters etc. for HOSR improvement. Cellular operators don't consider network synchronization as an important issue for call handover success rate. This article presents an investigation and analysis carried out on a live BSC (Base station controller) of a TDM GSM network in India deployed in Madhya Pradesh state to demonstrate how frequency drift of a BSC, resulting from poor synchronization can degrade HOSR. This article also presents the correlation between DAC word value (frequency drift) of a BSC and HOSR, and how DAC word value analysis can be used to assess HOSR degradation. In addition various methods for the performance evaluation of synchronization network, like clock quality, synchronization failure alarms, and clock frequency drift etc. and different issues and requirements with regard to synchronization of cellular network are presented.