can co-exist on the same infrastructure [@Liang] [@Rost2]. What’s more, due to the fact that the network is expected to be highly heterogeneous and extremely dense, it is natural to consider whether the network infrastructure can be virtualized and provided to whoever wants them and whenever they are acquired, so that the network operator is no longer hardware-limited, nor even software-limited, in the light of both of the hardware and software are owned by different and dedicated network infrastructure operators. By such, every component which used to be essential in the traditional network management can be viewed as a service, and then can be supplied to any (virtual) network operators/service providers (SPs) or even directed to the end-users. Correspondingly, we refer to the resulted system architecture as a service-oriented wireless network with Everything-as-a-service (XaaS) which traditionally is recognized as the service provisioning models in the cloud computing [@Duan]. The new XaaS in WNV will be indeed service-oriented, containing many new elements, such as Data-and-Knowledge-as-a-service (DKaaS), Computing-as-a-service (ComaaS), Radio-Access-Network-as-a-service (RANaaS), Cache-as-a-service (CaaS) and Energy-as-a-service (EaaS), which could be delivered over the advanced 5G infrastructure.

Despite the potential vision of XaaS in WNV, there are several remaining research challenges to be addressed 