A deeper look at 5G infrastructure Integrated
5G New Radio (NR) is a global standard for enhancing the 5G wireless air interface. NR will deliver a faster mobile experience in the low frequency band (below 1 GHz), the medium frequency band (1 GHz to 6 GHz) and the high frequency band (above 24 GHz millimeter wave). In this paper, we will discuss the frequencies above the high band millimeter wave spectrum, showing how integrated access and backhaul (IAB) opens the door for more flexible densification strategies, enabling operators to quickly add new base stations using radio backhaul. Challenges of Scaling 5G NR Millimeter Wave Network Coverage A key challenge to extensively expanding 5G NR millimeter wave network coverage is the cost of deploying additional millimeter wave base stations. Here are some other major mobile 5G millimeter wave issues and how to overcome them. An important aspect of such deployments will require reliable backhaul installations using new wireless backhaul infrastructure to make millimeter wave densification more cost effective. There will be path loss limiting coverage, which will require many small cell deployments; however, analog beamforming will help overcome path loss. Millimeter wave requires line-of-sight (LOS), which can limit signal propagation. Advanced beamforming and beam tracking will help by exploiting path diversity and reflections. Millimeter waves are only suitable for fixed applications. The solution here is to overcome blocked switching by adaptive beam control and switching. Millimeter wave requires large size because it consumes a lot of power and there are thermal challenges in small size. The solution is modem, RF and antenna solutions to meet form factor and thermal constraints through commercialization of smartphones. What is 5G IAB? Recently, 3GPP has proposed a process to standardize multi-hop IAB networks. This paper will provide an overview of the key features of multi-hop IAB proposed by the 3GPP Release 16 standard and the reasons behind these design choices. 3GPP 5G Release 16 introduces IAB to enable base stations to provide radio access and radio backhaul connectivity to devices, eliminating the need to install more costly wired backhaul. IAB refers to the use of a portion of the access spectrum for backhaul. Reasons for deploying wireless IAB versus fiber IAB 5G promises high bandwidth capabilities at high frequencies from the millimeter wave band. However, there is a problem in that HF deployments have limited coverage and require a denser base station layout. This will significantly increase the cost of deployment. A major factor contributing to this cost is the deployment of fiber that needs to be installed underground. IAB, where a portion of the radio spectrum is used for backhaul connections to base stations rather than fiber, is now an attractive solution for economically viable dense deployments. A key benefit of IAB is that it allows flexible and very dense deployment of new radio (NR) cells without the need to proportionally increase the density of the transmission network. A wide range of deployment scenarios can be envisioned, including support for small outdoor base station deployments, coverage extensions, indoor deployments, and fixed wireless access (FWA). As illustrated in Figure 1. Figure 1: IAB use case (Source: Integrated Access Backhauled Networks) First release feature of 3GPP Release 16. Multi-hop backhaul, which will allow range extension flexibility. Quality of Service (QoS) differentiation and implementation to meet 5G QoS, especially in the multi-hop case. Support for network topology adaptation and redundant connections for optimal backhaul performance and rapid adaptation to backhaul radio link overloads and failures. Access (e.g., UE links) and backhaul links (links to other network nodes) of IAB nodes use the same or different carrier frequencies for in-band and out-of-band trunking, respectively. Deployments supporting IAB nodes require legacy terminals that are transparent to the user equipment (UE) and therefore do not require new UE functionality or standardization. Verizon's plan is a good example of deploying wireless IAB with fiber IAB Verizon has embraced the deployment of IAB technology. This is important because until now, the carrier was using a large number of fiber connections to carry back traffic from its 5G transport sites. This is a costly and potentially restrictive requirement considering that it means Verizon can only install 5G antennas in locations where it can access fiber and power connections. By deploying a wireless IAB, Verizon may be able to install a 5G transmitter in a location where only electricity, rather than fiber, is available, as the wireless antenna can send its traffic back to a nearby receiver over a wireless link. This receiver will likely need to be connected to a fiber network. The IAB deployment will allow Verizon to install 5G antennas in locations where laying fiber optic cable may be difficult or expensive. A good example is the difficulty of embedding fiber optic cable in a set of train tracks. IAB is far superior to current wireless backhaul technologies, such as those using the 60-90 GHz E band, because it does not require a separate antenna for the backhaul link. As the term "integration" in the "integrated access backhaul" process suggests, IAB can support both wireless connectivity for regular 5G users and backhaul links using the same antenna. Deploying wireless IAB infrastructure in smart cities Urbanization is growing rapidly as people move from rural to urban areas. This places a burden on the infrastructure in these urban areas. Smart city deployments could be the savior of urban growth as they will alleviate these burdens. 5G technology is expected to be a turning point that will drive smart city technology into the mainstream while accelerating new deployments. 3GPP NR Release 16 sets out the wireless IAB, which is a key part of new deployments. The Smart City is a framework consisting primarily of information and communication technologies (ICT) that enable sustainable development practices to address the challenges of growing urbanization. The ICT framework consists of an intelligent network of connected objects and machines that can transmit data using wireless technologies and the cloud. Smart city residents will participate in the smart city ecosystem through smartphones and mobile devices as well as connected cars and homes. Deploying many Internet of Things (IoT) devices throughout a smart city will enable monitoring and management of environmental conditions and infrastructure. This effort can be costly. The survival of smart cities will depend on reducing costs. Smart cities require IoT devices to be connected to the Internet to access data from those devices. Deploying wireless IAB here allows base stations to provide wireless access and wireless backhaul connections to devices, eliminating the need for expensive wired backhaul. Wireless IAB also allows for faster deployment of base stations of all sizes to provide full coverage to communities in the most timely manner. Multi-hop IAB networks are now standardized thanks to 3GPP rel-16. Smart cities also provide the infrastructure to optimize energy distribution, improve waste collection, reduce vehicular traffic congestion, and improve air quality from the Internet of Things through true wireless communications deployments. Connected traffic lights will receive data from sensors and cars by adjusting the timing of light rhythms to respond quickly to real-time traffic while reducing congestion. Connected cars will wirelessly connect to parking meters and electric vehicle (EV) charging docks, directing drivers to the nearest available charging and parking area. Smart trash cans will wirelessly send data to waste management locations to optimize collection times. Residents' smartphones become mobile driver's licenses and ID cards with digital credentials for faster access to city and local government services. Thus, by using a portion of the large spectrum available on millimeter wave frequencies for wireless backhaul, the IAB will significantly reduce the cost of deploying 5G networks while achieving performance comparable to fiber deployments. Looking forward to 5G Release 17 Figure 2: 5G3PP Release 17 overview (Source: 5G3PP) 5G 3GPP Release 17 (Figure 2) has a new timeline, with progress delayed by the cancellation of face-to-face meetings due to the coronavirus. 3GPP resumes face-to-face meetings in the second half of 2021. The good news is that the content of Release 17 was approved at the December 2019 meeting. For more details, see the agreed Release 17 schedule on the 3GPP website. Wrap-up In this paper, we have explored the many challenges of the difficult task of extending the coverage of 5G NR millimeter wave networks. Prior to the advent of 5G 3GPP Release 16, fiber was an initial but costly option, with integrated access and backhaul as a very viable low-cost option. We have demonstrated that wireless IAB is a better solution in terms of cost and performance than fiber or any other proposal. Verizon's solution provides a good example. A major and relatively new area of 5G communications deployment is smart cities. This paper shows how wireless IAB is the perfect example of a dense deployment with comparable performance at 5G millimeter wave frequencies without the need for more expensive fiber connections to each base station. Translated with www.DeepL.com/Translator (free version)