The exponentially growing wireless data traffic has pushed wireless network vendors and researchers to think of a revolutionizing architecture for fifth-generation (5G) wireless networks is that is able to support 100 times the network capacity of the current 3G and 4G systems and yet is capable of reducing the net energy consumption of the systems by up to 90 percent. Numerous concepts and technologies have been proposed to approach this goal from various system-design aspects. A consensus reached so far is that 5G is going to be a collection of technology evolutions that include soft core networks, small cellular networks, pervasive but invisible base stations, and heterogeneous yet self-organizing radio access networks. Given the need for advanced radio access technologies, the success of such an ambitious goal relies on a flexible and scalable network infrastructure to accommodate and harmonize these technologies. In this chapter, we introduce a cloud service model and system architecture that has the potential to serve the numerous system requirements for future 5G networks.

A Cloud Service Model for Radio Access Networks

According to statistics released by [1], global mobile broadband subscriptions will reach 4.4 billion by 2016. The global mobile data traffic has almost doubled every year in the past four years, and is expected to reach 10.8 exabytes per month by 2016. This wireless tsunami has hit the global wireless infrastructure, and is causing wireless service providers to deploy many more base stations (BSs) and their access networks to satisfy the ever increasing service demands. This, however, gives rise to other threats such as increased energy consumption and radio pollution to our environment. According to statistics released by China Mobile, the number of its BSs exceeded one million by 2012 and continued to increase by more than 200 thousand a year. The overall power consumption to support such a huge wireless network reached 14 billion kilowatt hours (kW h) a year by 2012, and increased to 1.5 billion kW h a year on average over the period 2004-2012 [2]. Mobile wireless services have grown to a point such that even the network of one service provider needs to accommodate tens of millions of BSs and yet must be able to regulate the tremendous amount of traffic running through it.