Distributed algorithms for Wireless Physical Layer Network Coding self-organisation in cloud communication networks

Abstract

Communication networks of present-days are growing in complexity to follow a never-ending demand for fast, smooth, energy efficient and cheap connection. This demand is a driving force of new technologies. Two of them – cloud network concept and Wireless Physical Layer Network Coding (WPLNC) – are in the focus of this thesis. Both together represent a paradigm shift that can bring benefits to the networks of the future. With WPLNC the communicating nodes are no more separated in orthogonal resources, such as time, frequency or code space. Instead, they are allowed to overlap directly at the level of electromagnetic waves. Overlapping signals are no more considered as nuisance, rather, they form new super-signals that are processed as one. With slightly more complicated signal processing some big advantages in throughput, reliability and/or efficiency can be achieved by this technique. Cloud network concept introduces an intelligent network, that is able to react on changing conditions. The network is formed by self-aware relay nodes that cooperate to provide communication service to the terminals. The network is assumed distributed and decentralised to be able to react fast and adapt to local variations. WPLNC technique seems to be a favourable scheme for such a network. In this thesis I focus on distributed algorithms for implementation of WPLNC in the context of cloud network. The algorithms equip the relay nodes with ability to self-adapt and self-organise their WPLNC processing, such that it is aligned optimally across the whole network. Particularly, as an example an algorithm that assigns WPLNC mappings to individual relays is provided. This algorithm is transformed into a form of suitable communication protocol. Some other versions of the algorithm are proposed that focus on more complex situations – when the relays do not perform fair and try to harm the network or when some form of behaviour is dependent on relay node state, such as battery level. Whenever it is possible not only a mathematical solution of studied issues is provided but also software simulation is shown and more importantly a verification by hardware testing in real conditions is done and presented.