The mobile demands and future business context are anticipated to be resolved by the fifthgeneration (5G) of mobile communication systems. It is expected to provide an utterly mobile device, connected society, and support the demanding services of various use cases (UCs). This is intended to meet the demand requirement by providing services at tens of Gbps in terms of data rates, higher mobility range, lower latencies, and massive connectivity density devices per square kilometer. A comprehensive and up-todate survey of the different developed and proposed use cases is presented in this paper. The first part of the paper presents the overview of the new 5G Architecture by introducing new features such as the new radio interface (New Radio), an overview of the 5G Core Network, minimum requirements, and the Radio Access Network, 5G spectrum requirements and other fundamentals of the network. Secondly, a detailed review of the developed and proposed use cases for 5G communications by the standards development organizations (SDO) and other key players in mobile communication is provided. Thirdly, we went ahead to propose spectrum bands for the deployment of the various use cases based on the low-, mid-, and high-band spectrum and further classified the use cases with respect to their relevance and family, identifying the IMT-2020 test environments and the usage scenarios derived by the 3GPP, fourthly, the channel capacity and the bandwidth of the spectrum was studied, simulated and compared to ascertain the spectrum proposed in this paper for each UC family. Hence, this paper serves as a guideline for understanding the usage scenarios for the future 5G deployment in various environments. This would allow system developers to design and implement 5G channel characterization models specific to the usage scenarios to meet the system requirements.

The rapid development of wireless technology has sparked interest in multi-band reconfigurable antennas as devices and satellites are innovating toward miniaturization. With limited space, reliable and efficient high bandwidth antenna systems are needed for current and next-generation wireless technology as well as for the revolutionary small satellites. The fifth generation of mobile communication technology promises high data rates, low latency and good spectrum efficiency. One of the key enablers of this technology is the integration of satellite technology-particularly CubeSats with terrestrial communication technologies. Next-generation antennas that can meet functional requirements for 5G and CubeSat applications are therefore of fundamental importance. These antenna systems should have large bandwidth, high gain and efficiency and be compact in size. Reconfigurable antennas can provide different configurations in terms of the operating frequency, radiation pattern and polarization. Tuning reconfigurable antennas can be done by changing the physical parameters of the antenna elements through electronic switches, optical switches and the use of meta-materials. The most popular implementation method for

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In spite of the numerous advantages of employing free space optical (FSO) communication systems as viable complementary platforms for next-generation networks, the presence of atmospheric disturbances such as fog and scintillations are major sources of signal impairment which degrade system performance. Consequently, it becomes imperative to investigate and contextualize the unique climatic conditions in those locations where FSO links are to be deployed. Statistical evaluation of meteorological visibility data collected for various cities in South Africa is thus hereby employed in estimating the availability performance of FSO links transmitting at both 850 nm and 1550 nm. It is determined that the cities of Mbombela and Cape Town have the lowest performance due to the high occurrence of fog events as compared to other regions in South Africa. During foggy periods, FSO links in Mbombela and Cape Town would have availabilities of ~99.6% for link distances of 500 and 600 metres, respectively. The bit error rate (BER) estimations of intensity modulation and direct detection (IM/DD) FSO links in the presence of weak atmospheric turbulence were also investigated for the identified locations during foggy weather; with the cities of Mafikeng and Kimberley showing the lowest BER performances because of their high wind velocities, altitudes and refractive index values. In order to obtain a BER of 10 -6 , receive signal-tonoise ratio (SNR) values ranging from ~46 to ~51 dB are required for FSO links deployed for data transmission in the various cities investigated in this work.