Cellular service providers have been struggling with users’ demand since the emergence of mobile Internet. As a result, each generation of cellular network prevailed over its predecessors mainly in terms of connection speed.

This thesis tackles the optimization of energy efficiency in data centers in terms of network and server utilization.

In this thesis, signal propagation variations that are experience over the frequency resources of IEEE 802.11 Wireless Local Area Networks (WLANs) are studied.

The rapid growth of wireless mobile devices has led to saturation and congestion of wireless channels – a well-known fact. In the recent years, this issue is further exacerbated by the ever- increasing demand for traffic intensed multimedia content applications, which include but are not limited to social media, news and video streaming applications.

While the IEEE 802.11 protocol has fostered ubiquitous connectivity for wireless users, it was not originally designed to efficiently handle voice or video traffic, which nowadays accounts for most of the Internet traffic.

In the last decade, cellular networks are undergoing with a radical change in their basic design foundations. The huge increase in traffic demand requires a novel design of future cellular networks.

The future of network communications is mobile as user's demand for ubiquitous connectivity increases. Wireless has become the primary access technology, leading to an explosion in traffic demand. This challenges network providers to manage and configure new requirements without incrementing costs in the same amount. In addition to the growth in the use of mobile devices, there is a need to operate simultaneously different access technologies.

Radio-frequency based wireless communications have revolutionized our society. Thanks to important wireless communication technologies such as Wi-Fi, LTE, and so on, people can enjoy high data rate and pervasive connections while surfing the Internet. 

The Internet depends on economic relationships between ASes (Autonomous Systems), which come in different shapes and sizes - transit, content, and access networks. CDNs (Content delivery networks) are also a pivotal part of the Internet ecosystem and construct their overlays for faster content delivery. 

In the last years, the commercial deployment of data services in mobile networks has been evolving quickly, providing enhanced radio access technologies and more efficient network architectures.