  Next generation (5G) wireless networks are expected to support the massive
data and accommodate a wide range of services/use cases with distinct
requirements in a cost-effective, flexible, and agile manner. As a promising
solution, wireless network virtualization (WNV), or network slicing, enables
multiple virtual networks to share the common infrastructure on demand, and to
be customized for different services/use cases. This article focuses on
network-wide resource allocation for realizing WNV. Specifically, the
motivations, the enabling platforms, and the benefits of WNV, are first
reviewed. Then, resource allocation for WNV along with the technical challenges
is discussed. Afterwards, a software defined networking (SDN) enabled resource
allocation framework is proposed to facilitate WNV, including the key
procedures and the corresponding modeling approaches. Furthermore, a case study
is provided as an example of resource allocation in WNV. Finally, some open
research topics essential to WNV are discussed.
