(e.g., frequency, time, and space) or wireless equipment (e.g., a base station (BS)³, a network device (e.g., a router), a network, or a client hardware (e.g., wireless NIC). 3 A single physical BS can be abstracted to support multiple mobile operators and allow individual control of each RAN by having a separate vBS configured for each operator. 2.4 Wireless Virtualization Thus, similar to wired network virtualization, wireless network virtualization software may reproduce logical channel and logical RAN (L1) in addition to logical switches and logical routers (L2-L3). The motivations for virtualizing wireless networks are very similar, but not limited, to those of wired networks. First, as an extension of wired network virtualization, wireless virtualization can potentially enable separation of traffic to increase flexibility (e.g., in terms of QoS), improve security, and facilitate manageability of networks. Powerful network management mechanisms are particularly important in emerging heterogeneous networks. Second, it has a great potential to increase the utilization of wireless networks. This is important from both infrastructure and spectrum virtualization points of view. The former opens up the doors for the concept of IaaS SO that one operator can use its own or other operator's underutilized equipment (e.g., BSs on the outskirts) in the congested sites, for example, in downtown. Spectrum virtualization can also provide better utilization; it may even bring more gain and is more valuable as spectrum is a scarce resource. Third, by decoupling the logical and physical infrastructures, wireless virtualization promotes mobile virtual network operators (MVNOs4). This allows decoupling operators from the cost of infrastructure ownership (capital and operation expenditures). Fourth, wireless virtualization provides easier migration to newer products and will likely support the emergence of new services. Last but not the least, it is a key enabler for cloud radio access network, which is expected to help operator