providers in the XaaS framework also call for research efforts. In addition, mobility issues also course challenges in a converged network and cloud environment. Two dimensional mobility in both physical and virtualized wireless networks, should be taken into consideration for service provisioning. The problem can become more serious when the mobile devices are the resources to offer the services, which may make the service discovery and provisioning more complex.

Big Data Analytic
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Both proposed XaaS and WNV heavily rely on effective development of big data processing technologies. At the moment, the traditional cellular networks and recent cloud-RAN are not designed for the incoming big data era and needs sufficient revision to enhance the capabilities for big data analytic. To realized the XaaS, various features of networks should be either improved or total renovated. Exploring advanced big data analytical tools, such as stochastic modelling to capture the dynamic features of big data, development of data mining and machine learning algorithms, distributed optimization and dimension reduction. In addition, some features should be developed and brought into the current cellular networks to future explore their capabilities for handling vast volume of data, such distributed caching, computing, quantization and compression, investigation of the 