## 1 Introduction
### Review of Related Works
#### 1.1.3 Design Considerations  
Moreover, although, broadband networks such as fiber-to-the-home (FTTH) or digital subscriber line (DSL) variants are widely deployed in the network, fixed wireless access (FWA) systems can be employed in an area or scenario where it is technically or economically unviable to exploit other wireline solutions. Based on this, FWA systems were developed to offer higher transmission rates by exploiting a higher portion of radio spectrum bands [5; 8; 9; 27; 69]. Nonetheless, it has been observed that conventional FWA services are only limited to certain users. This is as a result of the associated high-cost and high-physical footprint of the employed equipment. To address this, a lightweight and compact wireless terminal (WT) with high antenna gain for outdoor and indoor use was presented. Design of WT that mainly focuses on a unique antenna and RF module for a point-to-multipoint (PtMP) FWA system known as Wireless IP Access System (WIPAS) was described in [70; 71]. To improve the performance of WIPAS, an advanced WIPAS was presented with system specifications and concepts in [72; 73]. Furthermore, prototype models were developed and evaluated. A generalized joint-optimization framework for planning wireless access and optical transport concurrently for 5G FWA networks was presented in [23] to reduce the related deployment cost and to meet several network requirements. Furthermore, a market, as well as system overview on FWA, were examined in [74]. Furthermore, the demand for very high throughput and seamless coverage in the 5G wireless networks is one of the strong motivations for the implementation of higher segments of the frequency spectrum. In this regard, radio system designers have been paying considerable attention to the practical application of millimeter-wave (mm-wave) communication. Therefore, to support different broadband services, 5G FWA is expected to leverage mm-wave technology. Based on this, several research efforts have been presented in [75; 76; 77; 78; 79; 80; 81; 82] to exploit the scheme and enhance its performance considerably. In [83], the propagation characteristics and the potential of leveraging the E-band spectrum for mobile broadband communications were discussed. Furthermore, means of addressing the coverage problem to improve the system performance in the network area were presented. Besides the mm-wave technology, ultra-dense small-cell will be deployed in the 5G FWA to improve the network penetration, efficiency, and reliability; however, this results in additional expenses. The related cost can be alleviated with the implementation of advanced multi-antenna technologies in which beamforming (BF) techniques and advanced signal processing are implemented. Therefore, there are several articles in which advanced multi-antenna and BF technologies are considered to attend to the issue and ensure seamless connectivity as well [84; 85; 86; 87; 88; 89; 90; 91; 92]. Furthermore, in [93], an optical BF architecture that was based on dispersive media and optical switches was experimentally demonstrated. The architecture presents a number of salient features such as huge bandwidth, potential fast-switching, and immunity to electromagnetic interference (EMI) which make it attractive for fixed and mobile broadband access networks that operate at the mm-wave band. In addition, note that radio propagation conditions at higher frequency bands are relatively demanding; this is due to the inherent lossy nature and high susceptibility to environmental conditions. As the propagation condition determines a suitable application scenario for the system deployment, there are several studies on the effect of environmental and climatic conditions on the FWA channel quality of service (QoS). In [94], building penetration loss was analyzed, and measurement results on high-frequency band FWA were presented for the related losses for houses with plain-glass windows and low-emissivity windows.