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Top1. Introduction
The Fifth-Generation wireless technology is one of the most anticipated upcoming technologies. A survey which was undertaken by Ericsson in 2017, Ericson (2017), concluded that 92% of executives in charge of at least 100 of the major telecommunication operators worldwide, agree that 5G will clear the way for a substantial number of emerging technologies. The 5G infrastructure will primarily serve as a foundation for heterogeneous wireless networks, providing seamless connectivity that will trigger the proliferation of smart cities across the entire globe. On the other hand, there has been significant advances in hardware manufacturing technology (Bhushan & Sahoo, 2018) that has resulted in the development of minute battery powered sensors which are able to connect directly and communicate with some 5G elements in a D2D fashion. According to Rathee, Ahuja and Nayyar (2019), these sensors have the capability of expanding interconnectedness, courtesy of IoT. Figure 1 presents ProSe-enabled devices that have ProSe applications running on them.
Figure 1. Adding a ProSe-enabled sensor to the architecture. Adapted from 3rd Generation Partnership Project (3GPP) Organisational Partners (2017).
As can be seen in Figure 1, several interfaces have been introduced, the most notable ones being PC3 and PC5 (3GPP 2017:13). The functions of these interfaces are outlined in Table 1.
Table 1. | Interface | Function |
| PC3 | The interface is used by UEs to connect to a ProSe Function |
| PC5 | This interface can be used by UEs or devices like sensors to connect directly to each other in a D2D fashion |
As can be observed in Figure 1, ProSe-enabled devices can communicate with a ProSe Function by making use of PC3 to obtain information for network related actions. The ProSe-enabled devices can obtain authorisation from a BS to participate in a D2D session via PC3. This direct communication, however, comes with a cost to the overall 5G QoS. According to Mach, Becvar and Vanek (2015), when external devices such as ProSe sensors (3GPP, 2014), are to communicate directly within an underlying 5G network, the following types of interference arise:
These types of interference pause a substantial risk to cellular networks, and this has prompted many researchers to look for methods of dealing with the resulting interference. According to Mwashita and Odhiambo (2018), the following interference management schemes have been identified: