OTN/WDM Technology Application for Implementing Xhaul Architecture in C-RAN Environment

Very often reading and talking about 5G or the next generation network, we have an idea as huge as confused. We could find in many papers in literacy a lots of several issues and several facets that describe the new access network generation; from these ones, for example, we can mention an expected number of connected devices and forecast traffic that are more than 1000-fold actual values. This increasing number of wireless devices, the increasing required traffic bandwidth and the high power consumption lead to a revolution of mobile access networks, that will be not a simple evolution of traditional ones. Another point of difference with the actual network will be the presence of different classes and qualities of service necessary for providing different service types. As consequences of the intense research studies done in these years, a large number of emerging technologies that could achieve the above requirements are developed. One of these technologies is Cloud Radio Access Network (C-RAN), that is seen as promising solution in order to deal with the heavy requirements of bandwidth capacity and energy efficiency, defined for 5G mobile networks. The introduction of the Common Public Radio Interface (CPRI) technology allows for a centralization in Base Bandwidth Unit (BBU) of some access functions, with advantages in terms of power consumption saving when switching off algorithms are implemented. Unfortunately, the advantages of the CPRI technology is to be paid with an increase in bandwidth to be carried between the BBU and the Radio Remote Unit (RRU), in which only the radio functions are implemented. However, one of the most import factors, that could sign a great boost in the new generation network, will be how these technologies could work together in order to improve the whole network performance and, consequently, the possibility to have a ``network slicing", in which different service types could be managed by a carrier client. Thus, it is simple to think that one of the most important key drivers in 5G networks has to be the flexibility in managing of different radio access technologies. The OTN/WDM technology application could be important to achieve a great level of flexibility and to save resources in the 5G access network, where there will be a dense deployment of network elements like Base Station or WiFi access points. In this scenario, a trade-off solution between power and bandwidth consumption may be needed. In this thesis, it is proposed and evaluated a network solution that consists in handling and carrying the traffic generated by the RRUs and RBSs (CPRI and Ethernet flows) with a reconfigurable network based on Optical Transport Network (OTN) technology. After proposing some energy and cost-efficient OTN/WDM switch architectures and resource dimensioning analytical models, it is shown how the sum of the bandwidth and power consumption may be minimized with the deployment of a given percentage of RRU out of the total number of radio elements. It is important to note that the achievement of this results is only possible if the network has the capacity to efficiently manage a large number of base stations and, thus, it is able to exploit the gain related to the statistical multiplexing effects