Location management strategies for personal communications services networks.

摘要

Location management provides key functions for Personal Communications Services (PCS) networks to support global roaming of mobile subscribers. As the number of mobile subscribers increases, as the cell sizes become smaller to increase the reuse of bandwidth, and as new features and services are introduced, the loads on the databases and the signaling network will be increased dramatically. Due to the scarcity of wireless bandwidth as well as the limited capacity of the signaling network and databases, current methods for location management may become inefficient in future PCS networks, and new and improved strategies will be necessary to meet these future demands.; This thesis proposes four location management strategies that can be used for distinct functions in PCS networks. A location-based location update scheme is proposed, which can adapt dynamically to users' individual calling and mobility patterns and is easy to implement. For user location information distribution, an integrated location information management strategy based on the two-level location database architecture is proposed. The proposed strategy is suitable for users with a wide range of call-to-mobility ratio (CMR) values. To support global roaming in a PCS system using the location-independent numbering plan, a multi-tree database structure and two memory-resident database indices are proposed. The proposed database structures can handle high access rates to the location databases, thus supporting high user densities. For deregistration, a lazy deregistration strategy is proposed, resulting in reduced database access loads and signaling traffic.; The present study found that in general women reported relatively low levels of distress at baseline, and while distress levels did fall over the course of the study, there was no unique intervention effect on distress per se. The present intervention was, however, associated with feelings of positive contributions from the experience of having breast cancer. The intervention also resulted in improvements in proliferative response to anti-CD3. It also appears that changes in positive contributions as a result of the intervention may be partially mediating the effects of the intervention on changes in proliferation. Interestingly, women in the intervention were also less likely to miss work due to illness over the 6 month follow-up.