Telcos are adapting their business to address the rapid changing technology landscape (Moodley and van Olst 2011). Telcos require a flexible architecture to allow seamless adaptation and to leverage these new technologies to gain a competitive advantage (Moodley and van Olst 2011). This research is focused on the transport stratum as an extension to the OSA/Parlay gateway. The proposed OSA/Parlay Network Architecture and Interface has been designed. The OSA/Parlay Network Interface is characterised by openness, simplicity, API based, QoS support and technology independence. The OSA/Parlay Network Architecture features simplicity, technology independence, QoS mechanisms; call admission control; intelligent routing and supporting both federation of telcos and interoperation of legacy technologies. The OSA/Parlay Network Architecture and Interface has been demonstrated over a Java based Distributed Processing Environment (DPE) using CORBA. These architectural concepts and principles are demonstrated in a simulated environment and illustrate the Next Generation Network architectural characteristics. The research contribution therefore achieves an open architecture allowing for 3rd party application developers while also ensuring that call and service requests are provisioned end-to-end with guaranteed application level QoS in the transport network. The OSA/Parlay Network Architecture and Network Interface is synthesised from existing architectural standards and provides the following benefits. It is an extension of the OSA/Parlay standard by including the OSA/Parlay Network Architecture and Network Interface realises the OSA/Parlay next generation network. Both the OSA/Parlay Network Interface and the Network Architecture is specified in a technology agnostic manner. This ensures that the architecture remains future proof as it is not reliant on any particular technology. The long sought after Application level QoS is integrated into the architecture. The periodic network state updates inform the central Connection Coordinator object of both topological network changes as well as current performance of the constituent parts of the network. Intelligent routing of connections is achieved by adapting the Dijkstra algorithm to compute the best path based on dynamic network performance and is tested against QoS requirements, while the call admission control decision naturally allows for load balancing of connection paths within the network. This QoS mechanism achieves the goal of guaranteed QoS for a call admitted into the network.

Clock synchronization in a wireless sensor network (WSN) is essential as it provides a consistent and a coherent time frame for all the nodes across the network. Typically, clock synchronization is achieved by message passing using carrier sense multiple access (CSMA) for media access. The nodes try to synchronize with each other, by sending synchronization request messages. If many nodes try to send messages simultaneously, contention-based schemes cannot efficiently avoid collisions which results in message losses and affects the synchronization accuracy. Since the nodes in a WSN have limited energy, it is required that the energy consumed by the clock synchronization protocols is as minimum as possible. This can be achieved by reducing the duration for which the clock synchronization protocols execute. Synchronous clock synchronization protocols in WSNs execute the clock synchronization process at each node, roughly during the same real-time interval, called synchronization phase. The duration when there is no synchronization activity is called the synchronization interval. Synchronization phases are divided into synchronization rounds. The energy consumed by these protocols depends on the duration of the synchronization phase and how frequently the synchronization phase is executed. Hence, to minimize the energy consumption by each node, the duration of synchronization phase should be as small as possible. Due to different drift rates of the clocks, the synchronization phases at different nodes drift apart and special techniques are required to keep them in sync. An existing protocol, called improved weighted-average based clock synchronization (IWICS) uses a pullback technique to achieve this. If a message from (i + 1)th synchronization round is received by a node still executing the ith synchronization round, the receiving node reduces its next synchronization interval to ensure greater overlap in the synchronization rounds. The reduction in overlap is a gradual and continuous phenomenon, and so, it can be detected and dealt with continuously. In this thesis, first, we make use of TDMA-based MAC protocols, instead of CSMA, to deal with the problem of message losses. We discuss the challenges of using TDMA-based MAC protocols for clock synchronization and how to overcome these challenges. Second, The IWICS protocol calculates the virtual drift rate which we use to modify the duration of the synchronization interval so that there is more overlap between the synchronization phases of neighbouring nodes. We refer to this technique as drift rate correction. Finally, we propose a different pullback technique where the pullback detection is carried out in each of the synchronization phase as opposed to the old pullback mechanism where it would be detected only when an out-of-round synchronization message is received. The proposed pullback technique when applied to the current synchronization interval ensures that the synchronization phases, that follow the current synchronization interval, are better synchronized with each other. As a result of this, we are able to reduce the duration of synchronization phases further. The IWICS protocol with all these modifications incorporated is termed as the TIWICS (TDMA-based IWICS) protocol. Simulation and experimental results confirm that the TIWICS protocol performs better in comparison to the existing protocols.