the end-users in the XaaS platform, commonly comprise of heterogeneous services offered by different InSPs. For example, the combination of computing and radio resources, heterogeneous infrastructures (different types of BSs or other network elements), each of which has its own characteristics that may result in different technical approaches and solutions. In addition, the on-demand, programmable and flexible features of the XaaS framework also require dynamic and adaptive service composition. By predicting and overseeing the service performance and the user’s satisfaction level along the time, adaptation to QoS requirements will be beneficial for supporting elasticity of XaaS provisioning [@Duan1]. Thus, balance between system scalability, QoS awareness, user satisfaction, and service composition is a significant research issue.

Conclusions
===========

As one of the main concept enables infrastructure sharing and radio resources abstraction, wireless network virtualization emerges as a solution to reduce operation and management expenses of wireless networks. In this article, we introduced a revolutionary vision of the future 5G wireless networks, in which the network is no longer limited by hardware, radio resources or even software. Specifically, based on the idea of virtualizing wireless networks, the Everything-as-a-Service (XaaS) concept was presented and elaborated to light the way towards designing a service-oriented 