Future networks will comprise a wide variety of wireless networks. Users will expect to be always connected from anywhere and at any time as connections will be switched to available networks using vertical handover techniques. However, different networks have different Qualities-of-Service (QoS) so a QoS framework is needed to help applications and services deal with this new environment. In addition, since these networks must work together, future mobile systems will have an open, instead of the currently closed, architecture. Therefore new mechanisms will be needed to protect users, servers and network infrastructure. This means that future mobile networks will have to integrate communications, mobility, quality-of-service and security. However, in order to achieve this integration without affecting the flexibility of future networks, there is a need for novel methods that address QoS and security in a targeted manner within specific situations. Also, there is a need for a communication framework wherein these methods along with the communication and handover mechanisms could be integrated together. Therefore, this research uses the Y-Comm framework, which is a communication architecture to support vertical handover in Next Generations Networks, as an example of future communication frameworks that integrate QoS, security, communication and mobility mechanisms. Within the context of Y-Comm, research has been conducted to address QoS and security in heterogeneous networks. To preserve the flexibility of future network, the research in this thesis proposes the concept of Targeted Models to address security and QoS in specific scenarios: to address the QoS issue, a new QoS framework is introduced in this thesis, which will define targeted QoS models that will provide QoS in different situations such as connection initiation and in the case of handover. Similarly, to deal with the security side, targeted security models are proposed to address security in situations like connection initiation and handover. To define the targeted models and map them to actual network entities, research has been conducted to define a potential structure for future networks along with the main operational entities. The cooperation among these entities will define the targeted models. Furthermore, in order to specify the security protocols used by the targeted security models, an Authentication and Key Agreement framework is introduced to address security at different levels such as network and service levels. The underlying protocols of the Authentication and Key Agreement protocol are verified using Casper/FDR, which is a well-known, formal methods- based tool. The research also investigates potential methods to implement the proposed security protocols. To enable the implementation of some of the targeted security models, the research also proposes major enhancements to the current addressing, naming and location systems
