| Popis: |
The exponential growth of mobile data usage has brought about the necessity of scalable and manageable network implementations into the current wireless technologies. With the increase in the number of mobile users and better Grade of Service (GoS) demands, current solutions are not sufficient to maintain the transmission quality in heterogeneous Radio Access Technologies (RATs). Moreover, spectrum efficiency in RATs is becoming crucial due to the fixed channel allocation for small cell base stations. In addition to this, the lack of scalable global control for offloading mobile data traffic between RATs makes it difficult to manage flows and control networks. Therefore, in this chapter these challenges are addressed to maintain scalable, controllable and manageable next generation deployments. Specifically, in order to increase scalability of wireless systems without conceding GoS of each user, the mobile traffic can be offloaded to the best suitable small cell by the aid of a “virtual” central authority using a Software Defined Networking (SDN) approach. Thanks to this virtualization capability of SDN, without making any alteration in physical topology, the solutions can be developed. In this chapter, we first revisit the basics of SDN technologies. Then, in order to solve the static channel assignment, we use a Software Defined Network model. It includes two algorithms: the topology control algorithm, which clusters several OpenFlow (OF) switches using the flows’ GoS, and the flow admission control algorithm, which fairly distributes each virtual switch according to the user demands. We also present a software defined framework to identify the appropriate base stations to switch and offload high service demanding mobile users. |
