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Prospective demands of next-generation wireless networks are ambitious and will require cellular networks to support thousand times higher data rates and ten times lower round-trip latency [1]. While this data deluge is a natural outcome of the increasing number of mobile devices with data-hungry applications and the Internet of Things (IoT), the low latency demand is required by the future interactive applications such as “tactile internet,” virtual and enhanced reality, and online internet gaming. Overall mobile data traffic is expected to grow to 49 exabytes per month by 2021, a sevenfold increase over 2016 [2]. Mobile data traffic will grow at a compound annual growth rate of 47% from 2016 to 2021 as shown in Figure 11.1. Furthermore, the cellular infrastructure currently contributes approximately 2% of carbon footprint and 3% of worldwide energy consumption, as a result of more than three million base stations (BSs) worldwide [3]. Also, noting that the carbon emission of information and communication technologies (ICT) is predicted to increase from 170 metric tons in 2014 to 235 metric tons by 2020 [4]; these statistics led telecom industry, governmental institutions, and researchers to initiate green measures. With the increasing number of mobile broadband data users and bandwidthintensive services, the demand for radio resources has increased tremendously. One of the methods used by mobile operators to meet this challenge is to deploy additional low-powered BSs, such as smallcell BSs (SBSs) and microcell BSs (MSBs), in areas of high demand, as shown in Figure 11.2. The resulting