Design of energy-efficient next-generation telecommunications networks

© 2016 Dr. Sandu Padmapanie AbeywickramaOver the past 35 years, optical telecommunications networks have revolutionised almost every aspect of human interactions. The recent popularity of bandwidth- intensive applications and deployment of virtual private networks which span across the globe have resulted in the need for large amounts of data to be transported over the telecommunications networks. Currently, fifth-generation optical communication networks are widely deployed in order to cater for this increasing bandwidth requirement. Nonetheless, the sudden growth in information and communications technology has had a profound impact on the environment due to increasing electricity consumption and its non-negotiable contribution to global green house gas emissions. Therefore, energy-efficiency is becoming a critical factor in the design of next-generation telecommunications networks. This thesis presents a series of novel solutions to address the increasing energy consumption of telecommunications networks. The proposed solutions focus on three important segments of the telecommunications network, namely the optical fibre access network, wireless access network, and optical core network. First, an energy-efficient approach to enhance video-on-demand services over optical access networks is proposed. To date, video-on-demand has been identified as one of the top traffic contributors to the telecommunications network. Moreover, it is expected to become more popular in the foreseeable future. Therefore, a more scalable and energy-efficient video-on-demand delivery mechanism should be considered in the design of next-generation telecommunications networks. We propose a novel VoD solution that exploits the use of a local storage caching server which stores a collection of the most popular videos closer to the customer. In this work, we discuss the opportunities for quality-of-service improvements and their respective power consumption and cost trade-offs Second, we focus on the wireless access network segment. The wireless access network connects mobile users to the base stations via the use of radio waves in the ultra high frequency spectrum of the electromagnetic spectrum. In today’s cellular networks, due to the large number of base stations being deployed, the power consumption of these base stations is identified as the main contributor to the network power requirement, contributing to about 60% of the network power usage. We present an energy-efficient transmit power control mechanism considering a heterogeneous wireless access network and present two approaches to solve the transmit power control problem. Our solutions exploit dynamic transmit power control of the base stations considering temporal variations of the daily traffic demand. In this work, we present the simulation results and discuss opportunities to reduce the power consumption of the wireless network. Finally, we bring our focus towards the core network segment. The core network aggregates traffic from the access network segment and facilitates communication across large distances. Thus, the survivability of the network to maintain operation against failures in network equipment and infrastructure becomes an important parameter. We present an energy-efficient approach to enhance survivability of the core networks by exploiting the dual-homing architecture in the access network. In particular, we propose a protection scheme that protects core network data transmission against fibre and equipment failures and discuss some energy saving opportunities in the core network. Overall, the technical contribution presented in this thesis provides a series of energy- efficient solutions towards designing an energy-efficient next-generation telecommunications network. We also discuss some of the future research directions and interesting problems arising from our efforts