UBC Theses and Dissertations

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UBC Theses and Dissertations

Connection architecture and protocols to support user terminal mobiltity over an ATM/B-ISDN personal communications network Yu, Oliver T.W.


Future personal communications networks (PCNs) will support personal and terminal mobility based on the B-ISDN platform, and will likely employ ATM-based backbone networks to interconnect wireless mobile networks. This thesis addresses the problem of providing robust, fast and seamless network-wide handoffs over an ATM-based PCN to support non-restrictive terminal mobility and to maintain connection-oriented performances during calls in order to enable handoff transparency to users. A novel "mobile virtual circuit (MVC) connection architecture" is proposed in the ATM layer to facilitate fast handoffs and to allow mobile and non-mobile traffic to share connection resources. The proposed MVC maintains the current and the potential handoff connections terminated at the neighbouring base stations as a dynamic connection tree, which converges at a root node in the ATM-based backbone to enable connection reuse during handoff. To minimize resource overhead and to enable fast handoff, the proposed MVC predetermines routes for potential handoff connections during call setup and after each successive handoff, and employs the proposed robust and fast scheme of generic bandwidth reservation along the predetermined route to complete the establishment during handoff. A novel "general real-time connection rerouting service" in ATM/B-ISDN is proposed with capabilities that can be configured to support robust, fast and seamless call rerouting over fixed connections in general and to support call handoffs over ATM-based PCN in particular. This service includes: (1) a novel packet ordering synchronization transaction protocol (POSTP) to prevent call disruptions due to transient data loss and sequencing errors during the traffic rerouting phase; (2) a novel robust and fast resource reservation transaction protocol (RFRTP) to enable fast connection establishment over a predetermined route with optional localized rerouting over congested or failed links. To support general real-time connection control services (e.g., the proposed rerouting service), extensions to the SS7-based signaling network are proposed with source-routing associated-CCS and inband signaling to provide fast distributed signaling transport and synchronization data transport respectively. To facilitate robust handoffs or to maintain the probability of forced call termination due to handoff blocking under non-stationary call arrival condition, a novel "dynamic guard channel resource management architecture" is proposed to adapt the number of guard channels in each cell according to the current estimate of the handoff arrival rate derived from the current number of ongoing calls in neighbouring cells and the mobility pattern, so as to keep the handoff blocking probability close to the targeted objective while constraining the new call blocking probability to be below a given level. The proposed scheme is applicable to channel allocation over cellular mobile networks, and is extended to bandwidth allocation over the backbone network. It is demonstrated that fast, robust and seamless network-wide handoffs over an ATM-based PCN can be achieved by integrating the proposed service and architectures. Handoff performance is analyzed in terms of handoff processing delay and forced call termination probability.

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