Keywords

Introduction

Enabler Technologies

Mobile technology and communications have undergone a sea change in the recent past. Mobile technology has been evolving at a rapid pace, and mobile devices, since the current millennium, have witnessed many features including gaming, GPS navigation, messaging, and so on. The mobiles are even able to participate in cloud computing in the form of Mobile Cloud Computing (MCC). Largely computer technology also depends on small hand-held smart devices. Tablet computers associated with mobile computing have become popular phenomenon. Mobile technology plays a vital role in digital infrastructure used for computing. The 5G is fifth-generation technology which is the successor of 4G. The 5G technology provides wider frequency bands besides increased spectral bandwidth. It is better than its predecessor in terms of peak bit rate, spectral efficiency, increased device connectivity, concurrency, speed, low battery consumption, assured connectivity in all geographical regions, increased device support, low-cost infrastructure, and reliability.

As presented in Fig. 3.1, the enabler technologies of 5G have their role in making it useful in real-world applications. The technologies are associated with network management, massive MIMO, millimeter wave, heterogeneous networks, convergence of access and backhaul, massive machine-type communication, communication with low latency, ultra-lean design, spectrum sharing, and flexibility. The sections below in this book provide more details on the architecture of 5G technology, its underlying mechanisms, support for Device-to-Device (D2D) communication, Multiple-Input Multiple-Output (MIMO) enhancements, advanced interference management, enhanced utility of ultra-dense networks, spectrum sharing, and cloud technologies associated with 5G networks. It also proposes a methodology with spectrum broker with underlying components with delay aware and energy-efficient approach to leverage 5G base stations leading to reduction of energy consumption. The concept of queueing delays is considered while proposing the scheme for delay-sensitive communications with energy efficiency.

Fig. 3.1
A circle-spoke diagram of 5 G enablers lists ultra-reliable low latency communication, massive M I M O, the convergence of access and backhaul, millimeter wave, massive machine type communication, network management, heterogeneous network, spectrum sharing, and ultra-lean design.

5G enabler technologies

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The 5G network is based on various design considerations as explored in Agyapong et al. (2014), Marsch et al. (2016), and Gupta and Jha (2015). It has inherent support considerations for the use cases of IoT (Khalfi et al. 2017). There is provision to have better utilization of spectrum with 5G in an energy-efficient manner (Mavromoustakis et al. 2015). The notion of Software-defined radios (SDRs) with 5G technology can improve its controlling (Lin et al. 2015). With 5G networks, spectrum harvesting and energy are to be integrated for better results (Liu et al. 2015). There are some techniques discussed in Zhang et al. (2017) and Yang et al. (2016) for advanced spectrum sharing in 5G technology. Content-centric orientation and spectrum sharing are explored for 5G networks (Gur 2019). With 5G network in place, spectrum sharing among secondary users is investigated in Papageorgiou et al. (2020). SDN architecture for such networks is studied in Akyildiz et al. (2015). The contributions of this paper are as follows:

  1. 1.

    Investigation is made into architectures of 5G technology, MIMO usage in 5G, and D2D communication in 5G.

  2. 2.

    Focused on interference management, spectrum sharing, and ultra-dense networks with 5G technology.

  3. 3.

    Other areas explored with 5G include cloud computing technologies, design of energy efficient, and cooperative schemes with an algorithm and empirical study.

The remainder of the paper is structured as follows. Section 3.2 covers the architecture details of 5G. Section 3.3 throws light on the MIMO technology in 5G. Section 3.4 explores the D2D communication in 5G. Section 3.5 deals with the interference management for 5G. Section 3.6 covers the spectrum sharing with cognitive radio in 5G. Section 3.7 discusses the ultra-dense networks in multi-radio access technology association in 5G. Section 3.8 throws light on the cloud technologies for 5G. Section 3.9 covers the proposed methodology for the design of energy-efficient delay-aware cooperative scheme for 5G. Section 3.10 provides challenges and directions for future work. Section 3.11 concludes the paper.

Architecture of 5G

The 5G technology is the new global standard for mobile networks. It has the potential to have connectivity to more devices and machines with unprecedented possibilities. It is aimed at delivering multi-Gbps data speed with reliability, low latency, and massive capabilities. There are many important use cases of 5G. One important use case is the 5G network can be used for broad spectrum due to its reliability and high speed. It enables mission-critical communications and supports IoT technology. The 5G technology offers more flexibility and supports devices that need large-scale connectivity in future. It leverages mobile broadband, augmented reality, and virtual reality. The 5G technology bestows numerous benefits such as unprecedented speed, reliability, supporting future connectivity, and so on.

The 5G technology is equipped with advanced architecture with improved terminals and network elements. It also enables service providers to adopt it with advanced technologies to render value-added services to their customers. The upgradeability depends on cognitive radio technology with its features like location, temperature, and weather. Transceiver is made up of cognitive radio technology to enhance the operating efficiency. The technology can also distinguish the subtle environmental changes in its location and provide response to ensure high-quality and uninterrupted service.

As presented in Fig. 3.2, the 5G architecture is designed based on IP and the model is meant for both mobile and wireless networks. The 5G system consists of user terminal and is associated with many autonomous and independent radio access technologies. Each technology is treated as an IP link in the eyes of the Internet world. The IP-based approach is to have full control and routing IP packets in different application scenarios that involve sessions over the Internet between servers and client applications. It has flexibility provided to user in making decisions pertaining to routing of packets.

Fig. 3.2
A schematic representation of 5 G architecture presents a 5 G terminal connected to G P R S or EDGE, 3 G, W L A N, and L T E. They are connected to a streaming server, data server, server for real-time communication, and control system policy server.

Shows architectural overview of 5G

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As presented in Fig. 3.3, the policy router layer facilitates communication between applications and servers. It has provision for different kinds of communications over IP model. The 5G technology has a master core to have flexible convergence point for other technologies.

Fig. 3.3
A flow diagram represents the communication between the terminal, policy router, and server. The terminal has applications that connect to the I P network layer.

Shows communication between client applications and server

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As presented in Fig. 3.4, the master core technology associated with 5G has provision to have convergence point for different technologies such as photonic routers, beam transceivers, and nanotechnologies. It has support for concurrent approaches considering either 5G network mode or IP network mode. It is capable of controlling technologies and supports 5G-based deployments. It offers more flexibility, efficiency, power, and less complicated phenomena. There are many researchers proposed different architectures based on 5G. For instance, Integrated Access and Backhaul (IAB) architecture is proposed in Ranjan et al. (2022) for exploiting 5G technology. The 5G mobile architecture is discussed in Tudzarov and Janevski (2011), while the key enabling technologies of the 5G are discussed in Idowu-Bismark et al. (2019). Evolution of wireless technologies including 5G is explored in Gupta and Jha 2015 architectural overview of 5G technology.

Fig. 3.4
A flow diagram of the master core technology has the steps, namely. 1. User level with 5 G applications, 2. R A N level with access, 3. network level with I P network, and 4. core level with control network.

Master core technology associated with 5G

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Arora et al. (2020) explored the evolution of 5G network in terms of Internet of Things (IoT) technology. They discussed the importance of 5G networks in order to solve the problems of IoT in the area of speed and convergence. Ghosh et al. (2019) also focused on the evolution of 5G technology. It has covered time-sensitive communication, integrated access, and backhaul. Ahmad et al. (2020b) discussed the evolution of IoT in order to use 5G technology. They found that 5G brings several benefits to IoT use cases. Goyal et al. (2021) explored about architecture and underlying aspects of a green 6G network. Arsh et al. (2021) explored design requirements and further developments needed to have IoT that makes use of IoT. Chetri and Bera (2019) studied the possibilities of using 5G in IoT use cases in order to reap its benefits in terms of speed and fulfillment of the user needs.

Multiple-Input Multiple-Output Technology in 5G

Antenna Array for MIMO in 5G

In communications with wireless technology, MIMO is an improvement over its predecessor models for improving efficiency. MIMO enables a configuration that supports receiving and sending multiple signals concurrently. In fact, it is an improved and smart antenna technology that leverages performance in wireless communications. It is suitable for 5G technologies to reap its benefits. For 5G terminal, Abdullah et al. (2019b) designed multiple antennas in order to realize MIMO technology. It is presented in Fig. 3.5.

Fig. 3.5
An illustration of the system ground plane on the front surface of P C B has arrays of 8 antennas with 1.6 millimeters thick F R 4 substrates.

Antenna array for MIMO in 5G

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It is designed for 5G mobile terminal that can operate at 2.6/3.5 GHz. Single antenna is used in traditional communication systems. It has many issues such as obstructions in the propagation line. It is overcome with MOMO technology and that can be used to exploit 5G benefits. MIMO technology has many applications like home networks, mobile communication networks, wireless local area networks (WLANs), and digital television (DTV). More on the MIMO technology usage, its future possibilities are found in Sharawi (2017). For 5G mobile terminals, the MIMO system is explored in Abdullah et al. 2019a.

Device-to-Device Communication in 5G

D2D communication refers to the communication that is directly between two devices without having conventional infrastructure such as access point. There are technologies like Wi-Fi Direct and Bluetooth that support D2D communication as explored in Shen (2015). Cellular networks have no support for direct communication between devices. Among different possibilities with 5G networks, D2D is one of the kinds of communication expected. With the advanced standard of Long-Term Evolution (LTE), D2D is expected to be realized in 5G cellular networks. With 5G cellular networks, mmWave technology is becoming popular. In such networks also D2D is expected. This technology is known for high propagation loss and short wavelengths and inability to penetrate into solids. These conditions provide suitability to realize D2D communications.

As presented in Fig. 3.6, there is a visual representation showing the approach in which cellular communication and D2D communication takes place. For service providers, D2D communication has been not viable. However, with the emergence of 5G, the subject of D2D became important once again. There are many use cases for D2D such as local data services, coverage extension, and Machine to Machine (M2M) communication. With respect to efficient spectrum usage, secondary users associated with Cognitive Radio Network (CRN) can exploit D2D communication that has a potential to get rid of interference to primary users of the spectrum. D2D is also expected to complement MIMO-enabled networks and HetNets with high data rates and efficiency. There is possibility of noise resilience and enhanced system capability with MIMO and D2D technologies. System capacity is significantly enhanced with D2D with MIMO devices.

Fig. 3.6
An illustration of the cellular communication of two devices from the tower. Those devices communicate with other devices.

Illustrates device-to-device communication

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As presented in Fig. 3.7, there is direct communication between two mobile devices. It is possible with “operator controlled link establishment.” In this kind of D2D communication, both devices can exchange information without the involvement of base station. However, they are to be supported by the operator in order to have link established. As discussed in Adnan and Ahmad Zukarnain (2020), there are many challenges associated with D2D communication. The challenges are in selection, mode, control, power, security, privacy, management, interference, discovery, and device.

Fig. 3.7
An infographic of direct D 2 D communication with operator-controlled link establishment depicts that destination and source are connected by direct D 2 D communication. They are connected to B S by controlled links.

Overview of D2D communication

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Interference Management for 5G

Multi-tier 5G Architecture

Interference is one of the issues in 4G technology. Due to density in cell deployment, it caused interference. Especially co-channel interference is the main problem with traditional cellular networks. As discussed in Nam et al. (2014) interference management can be done with many techniques such as advanced receiver and joint scheduling. They proposed two kinds of interference management techniques with 5G. They are categorized into UE-side and network-side management of interference. In Hossain et al. (2014), it is opined that multi-tier architecture of 5G has mechanisms to have advanced interference management. 5G also promotes D2D communication, Quality of Service (QoS), and energy efficiency in spectrum usage. It is made possible with multi-tier architecture of 5G technology as presented in Fig. 3.8.

Fig. 3.8
An infographic of multi-tier 5 G architecture includes d 2 D communication between devices and other communications between users and femtocell, picocell, macro-cell, user broadband connection, and relay mobile phone network.

Multi-tier 5G architecture

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The 5G technology with its multi-tier architecture enables tier-based and traffic-based priorities. It has provision for energy efficiency, latency, and reliability. It also minimizes interference in the system. There are certain key challenges associated with interference management. The challenges include heterogeneity, balancing traffic load and coverage, restrictions of public and private usage, and management of priorities. Interference management in 5G is explored with system model and analysis can be found in Sanguinetti et al. (2015).

Spectrum Sharing with Cognitive Radio in 5G

Spectrum sharing is an important aspect of wireless communications. With respect to CRNs, there are users like primary users and secondary users. Wireless network usage is rapidly increasing due to its advantages and conveniences. However, design of a wireless communication system is challenging as it needs to consider many factors such as spectrum utilization efficiency, high Quality of Service (QoS), larger channel capacity, and higher data rate in order to meet the requirements of wireless users. Cognitive Radio (CR) is the technology innovation in which wireless communications are more flexible. It enables users to modify transmitting and receiving parameters without causing interference to primary and secondary users in order to achieve more efficient performance in wireless communications. There are two types of users known as Primary Users (PUs) and Secondary Users (SUs) based on the priority in the assigned radio frequency spectrum. Under a specified policy, both the users can coexist in the system. The licensed users of the band are known as PUs. And PUs can least it to SUs in such a way that SUs use the spectrum without causing harmful interference to PUs in either underlay or overlay approach. Spectrum sensing is an important function of CR system in an overlay fashion. It is meant for finding the presence of PUs in the given frequency band. Cooperative spectrum sensing (CSS) is “a solution to enhance the detection performance, in which secondary users collaborate with each other to sense the spectrum to find the spectrum holes.” With 5G technology, spectrum sharing has improved possibilities while serving different enabling networks. The concept of dynamic spectrum sharing is thoroughly discussed in Ahmad et al. (2020a), while how full spectrum sharing takes place with different approaches is found in Feng and Bing (2016). In Briones-Reyes et al. (2020), a Markov process is discussed in detail to have spectrum sharing efficiently for 5G systems with a mathematical model.

Ultra-dense Networks in Multi-radio Access Technology Association in 5G

Ultra-Dense Networks (UDNs) are the networks where there are more cells present than the users. Such networks are found to be useful to handle explosive data traffic in 5G networks in future.

UDN Moving Cells with 5G+ Network

It has heterogeneous cells even that can be moving in 5G environments. Instead of static RANs, it is possible to have dynamic and moving RANs in future with the emergence of 5G technology. This concept is explored with different possibilities in the world beyond 5G capabilities in Andreev et al. (2019).

Figure 3.9 illustrates the possibilities of moving ultra-dense networks with 5G+ design. There are different unprecedented possibilities with moving cells of UDN with 5G networks. The possibilities include predictive handover, multi-connectivity, dynamic blockage, fleet coordination, swarm formation control, on-the-fly association, space–time methodology, proactive cell discovery, dual mobility, computation offloading, and dynamic association. As discussed in Habbal et al. (2015), it is possible to have a selection of context-aware radio access technology when 5G networks are used with UDNs. They opined that extreme densification has improved capabilities with 5G technology.

Fig. 3.9
An infographic of U D N moving cells with a 5 G network has the following labels. Dual mobility, proactive cell discovery, predictive handover, fleet coordination, space-time methodology, multi-connectivity, on-fly association, and swarm formation control.

UDN moving cells with 5G+ network

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Cloud Technologies for 5G

Cloud computing has enabled many services that can be rendered in on-demand fashion. With the emergence of 5G technology, it is possible to have related services. As explored in Sabella et al. (2015), it is possible to have cloud technologies that provide benefits associated with 5G. They proposed an architecture known as Cloud-RAN that provides RAN services in pay per used fashion. In other words, they proposed a novel service known as RAN as a Service (RANaaS) that consists of the required cloud-based infrastructure to render RAN services. The proposed virtualization infrastructure is associated with the RAN service. Similarly, in Rost et al. (2014), cloud technologies are leveraged to support flexibility in 5G RANs. Provision of RAN services is provided through cloud offering based on the runtime needs of systems. RAN services are centralized and appropriate software functionality is provided. As discussed in Al-Falahy and Alani (2017), 5G technology-related services can be rendered with cloud services. Different 5G enabler technologies aforementioned can be used in cloud in order to provide scalable, on-demand, and location-transparent services.

Methodology

The Methodology of the Proposed Scheme

This section provides a methodology for the design of energy-efficient delay-aware cooperative scheme for 5G. The proposed scheme is energy-efficient and delay-aware that is used to ensure that the 5G technology usage is made with energy efficiency. The proposed scheme is built based on the architecture shown in Fig. 3.10. It has an important component known as spectrum broker. Spectrum broker is responsible to exploit TV White Spaces (TVWS) by managing the process associated with energy consumption. TVWS consists of spectrum available to support the design of energy-efficient systems. The proposed methodology works based on queueing delays.

Fig. 3.10
A flow diagram. Radio resource management is interconnected to T V white spaces respiratory and energy controller. The 5 G base station is interconnected to the energy module that links the energy controller.

The methodology of the proposed scheme

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As presented in Fig. 3.10, the proposed methodology has spectrum broker which takes care of energy efficiency by coordinating other components. The concept of queueing delays is considered while proposing the scheme for delay-sensitive communications with energy efficiency. The spectrum broker has mechanisms to achieve this. The broker coordinates with energy module in order to ensure energy-efficient communications. Simulation study with the proposed scheme shows the energy efficiency of the proposed scheme when compared with the state of the art.

Spectrum Band

The 5G technology offers diversified spectrum bands that meet different requirements. For instance, a low-band spectrum with less than 1 GHz is desirable to many customers through it can provide latency incrementally.

5G Base Station

The 5G base station is a very powerful device that can help in supporting latency and also connectivity beyond the existing standards.

Energy Module

Energy module is responsible to help energy controller in order to achieve energy-efficient approaches with 5G technology.

Energy Controller

Energy controller works in tandem with energy module and radio resource management module for achieving energy efficiency.

Algorithm 1

Pseudocode of the proposed scheme

A pseudocode of the proposed scheme has 15 steps. It starts with setting up the 5 G base stations, followed by activating radio resource management.

The proposed scheme is delay-aware and energy efficient. It continuously monitors TVWS in order to have opportunities to help 5G base stations to have energy-efficient functionality.

As presented in Fig. 3.11, the energy efficiency of the proposed system is compared with the scheme of Mekikis et al. (2014). The proposed scheme is found to be energy-efficient.

Fig. 3.11
A double paragraph of delay per request versus energy plots the increasing bars of the scheme in 22 and the proposed scheme. The scheme in 22 has higher values.

Performance comparison in terms of energy efficiency

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Challenges and Future Research Directions

Exploration of spectrum resources in 5G has its advantages in order to have better optimization of resource usage. Though 5G technology is found to be a game changer, it has certain challenges that are to be understood and addressed. The first challenge is to have 5G infrastructure or network development which needs small-cell technology in order to increase network capacity. The second challenge is that of the cost involved in the 5G infrastructure. Microcell costs are more and the cost is going to play its role in making obstructions in its adoption. The third problem is that 5G technology has issues with backhaul and coordination with current cellular technology. The fourth problem is that there is a challenge related to the provision of necessary bandwidth with wave spectrum in the presence of trees, buildings, and other objects acting as obstacles. The fifth challenge is that 5G has certain security challenges in terms of vulnerabilities in the existing infrastructure and new infrastructure. In the presence of these challenges, it is essential to have further research to acquire ways and means to handle these challenges.

Conclusion

This chapter has focused on different aspects of 5G technology and its impact on various communication technologies. It presents the architecture of 5G technology, its underlying mechanisms, support for D2D communication, MIMO enhancements, advanced interference management, enhanced utility of ultra-dense networks, spectrum sharing, and cloud technologies associated with 5G networks. It also proposes a methodology with spectrum broker with underlying components with delay-aware and energy-efficient approach to leverage 5G base stations leading to reduction of energy consumption. The concept of queueing delays is considered while proposing the scheme for delay-sensitive communications with energy efficiency. The spectrum broker has mechanisms to achieve this. Simulation study with the proposed scheme shows the energy efficiency of the proposed scheme when compared with the state of the art.