Wireless access techniques have developed in a so fast speed and varieties of bandwidth-hungry applications and services such as web browsing, video streaming, gaming, and social networking are gradually shifted to mobile networks, which leads to an exponential increase in data traffic in mobile networks. Meanwhile, modern mobile systems are upgrading at a tremendous speed. Devices of this date such as smartphones and tablets deploy powerful multicore CPUs, fast memory, and smart sensors, which means that the performance of the devices is getting better. Therefore, mobile users are able to complete demanding tasks and enjoy convenient mobile services. For better user experience, mobile operators are upgrading the infrastructure to long-term evolution (LTE) and LTE-advance (4G) for better access capacity and services. However, currently cellular networks, even like 4G networks, do not have enough capacity to accommodate an exponential growth of data. According to Cisco forecasts [1] and practical experiences of mobile operators, we are now facing the mobile data apocalypse. The number of mobile-connected devices has already exceeded the number of people on Earth, while by 2017 there will be nearly 1.4 mobile devices per capita. Thus, there is urgency for the research community to look for new solutions [2].