This thesis proposes a new multi-homing mobile architecture for future heterogeneous network environment. First, a new multi-homed mobile architecture called Multi Network Switching enabled Mobile IPv6 (MNS-MIP6) is proposed which enables a Mobile Node (MN) having multiple communication paths between itself and its Correspondent Node (CN) to take full advantage of being multi-homed. Multiple communication paths exist because MN, CN, or both are simultaneously attached to multiple access networks. A new sub layer is introduced within IP layer of the host’s protocol stack. A context is established between the MN and the CN. Through this context, additional IP addresses are exchanged between the two. Our MNS-MIP6 architecture allows one communication to smoothly switch from one interface/communication path to another. This switch remains transparent to other layers above IP. Second, to make communication more reliable in multi-homed mobile environments, a new failure detection and recovery mechanism called Mobile Reach ability Protocol (M-REAP) is designed within the proposed MNS-MIP6 architecture. The analysis shows that our new mechanism makes communication more reliable than the existing failure detection and recovery procedures in multi-homed mobile environments. Third, a new network selection mechanism is introduced in the proposed architecture which enables a multi-homed MN to choose the network best suited for particular application traffic. A Policy Engine is defined which takes parameters from iv the available networks, compares them according to application profiles and user preferences, and chooses the best network. The results show that in multi-homed mobile environment, load can be shared among different networks/interfaces through our proposed load sharing mechanism. Fourth, a seamless handover procedure is introduced in the system which enables multi-homed MN to seamlessly roam in a heterogeneous network environment. Layer 2 triggers are defined which assist in handover process. When Signal to Noise Ratio (SNR) on a currently used active interface becomes low, a switch is made to a different active interface. We show through mathematical and simulation analysis that our proposed scheme outperforms the existing popular handover management enhancement scheme in MIPv6 networks namely Fast Handover for MIPv6 (FMIPv6). Finally, a mechanism is introduced to allow legacy hosts to communicate with MNS-MIP6 MNs and gain the benefits of reliability, load sharing and seamless handover. The mechanism involves introducing middle boxes in CN’s network. These boxes are called Proxy-MNS boxes. Context is established between the middle boxes and a multi-homed MN.

Environmental concerns and long term energy security are the key drivers behind most current electric energy policies whose primary aim is to achieve a sustainable, reliable and affordable energy system. In a bid to achieve these aims many changes have been taking place in most power systems such as emergence of new low carbon generation technologies, structural changes of power system and introduction of competition and choice in electricity supply. As a result of these changes, the level of uncertainties is growing especially on generation side where the locations and available capacities of the future generators are not quite clear-cut. The transmission network needs to be flexibly and economically robust against all these uncertainties. The traditional operation of the network under preventive control mode is an inflexible practice which increases the total system cost. Corrective control operation strategy, however, can be alternatively used to boost the flexibility, to expedite the integration of the new generators and to decrease the overall cost. In this thesis, the main focus is on development of new techniques and methodologies that can be used for modelling and solving a transmission planning problem under the assumption that post-contingency corrective actions are plausible. Three different corrective actions, namely substation switching, demand response and generation re-dispatch are investigated in this thesis. An innovative multi-layer procedure deploying a genetic algorithm is proposed to calculate the required transmission capacity while substation switching is deployed correctively to eradicate the post-fault network violations. By using the proposed approach, a numerical study shows that the network investment reduces by 6.36% in the IEEE 24 bus test system. In another original study, generation re-dispatch corrective action is incorporated into the transmission planning problem. The ramp-rate constraints of generators are taken into account so that the network may be overloaded up to its short-term thermal rating while the generation re-dispatch action is undertaken. The results show that the required network investment for the modified IEEE 24 bus test system can be reduced by 23.8% if post-fault generation re-dispatch is deployed. Furthermore, a new recursive algorithm is proposed to study the effect of price responsive demands and peak-shifting on transmission planning. The results of a study case show that 7.8% of total investment can be deferred. In an additional study on demand response, a new probabilistic approach is introduced for transmission planning in a system where direct load curtailment can be used for either balancing mechanism or alleviating the network violations. In addition, the effect of uncertainties such as wind power fluctuation and CO2 emission price volatility are taken into account by using Monte Carlo simulation and Hypercube sampling techniques. Last but not least, a probabilistic model for dynamic thermal ratings of transmission lines is proposed, using past meteorological data. The seasonal correlations between wind power and thermal ratings are also calculated. £26.7 M is the expected annual benefit by using dynamic thermal ratings of part of National Grid's transmission network.

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