1 Networks Technology and Service Platforms, Department of Photonics Engineering, Technical University of Denmark2 Department of Photonics Engineering, Technical University of Denmark3 Copenhagen Center for Health Technology, Center, Technical University of Denmark
The next generation of broadband access networks is expected to be heterogeneous. Multiple wired and wireless systems can be integrated, in order to simultaneously provide seamless access with an appropriate Quality of Service (QoS). Wireless networks support ubiquitous connectivity yet low data rates, whereas optical networks can offer much higher data rates but only provide fixed connection structures. Their complementary characteristics make the integration of the two networks a promising trend for next generation networks. With combined strengths, the converged network will provide both high data rate services and connectivity at anytime and anywhere. One major challenge in the interworking is how to achieve seamless integration. There are many aspects involved in designing an integrated control platform, such as QoS provisioning, mobility, and resiliency. This dissertation introduces the complementary characteristics of the optical networks and the wireless networks, addresses motivations for their interworking, discusses the current progress in hybrid network architectures as well as the functionalities of a control system, and identifies the achieved research contributions in the integrated control platform design. To achieve an integrated and unified control platform, enhanced signalling protocol plays an important role in gluing the two different technologies. Consequently, an integrated resource management system is developed. Furthermore, and admission control scheme for connections in the wireless domain can be jointly designed with the optical upstream bandwidth allocation scheme in the optical domain. Higher resource utilization is achieved due to an effective manipulation of the overall resources of two networks. In the converged optical and wireless network scenario, multiple wireless networks are adjacent to the backbone optical network. Althought the local resource allocation mechanisms implemented in the wireless networks individually can provide certain levels of QoS provisioning, proper load balancing and resource allocation schemes are needed in order to utilize the integrated resources effectively and efficiently. an integrated load balancing mechanism is proposed to take advantage to the centralized control in the optical network. A modified signalling protocol is developed to improve information exchanged between optical can wireless domains. Traffic load and network resources are distributed based on the network states, channel conditions, and QoS requirements. A new aspect in the design of future network is the energy efficiency. An energy management mechanism is proposed and evaluated for the optical network. With regard to power saving, a sleep mode operation is developed. Therefore, power is conserved by switch off some operating functions. The sleep period and wake up period are computed and assigned using two alternative scheduling schemes, which show trade-off performances on energy efficiency, queuing delay and network bandwidth utilization. To summarize, this dissertation presents new knowledge by developing a novel integrated control platform for the converged optical and wireless network. Several contributions are presented by investigating network architectures, protocols, and energy issues to obtain hybrid networks.