This article is a mash-up of a few of the important issues for 5G network design. In no way is it meant to be comprehensive to cover every theme as this topic is massive in both scope and complexity. But, these first principle topics are the essentials to gaining deeper insights into 5G and how it is different compared to previous cellular generations.
The architecture of a 5G network will be radically different compared to previous generations such as 2G, 3G, and 4G / LTE. In the past generations, they were all principally centrally organized. With 5G, we will continue to use a central orchestration but now blend it with a distributed design to create a federated architecture.
A federated architecture is an IT approach that allows interoperability and information sharing between semi-autonomous de-centralized organized lines of business, technology systems, and applications.
The analogy that I often use to understand this architectural model is to compare it to the Canadian governmental design. We have the three layers of government – Federal, Provincial, and Municipal. Each layer of government has separate and unique functions to perform. For example, the Federal layer delivers services such as the Military and Foreign Affairs, the Provincial level provides services such as Hospitals and Educations, and the Municipal level provides services like Roads, Garbage Collection, and local Policing. Yet, in a crisis situation these layers can support each other and the architecture of government can “make and break’ upon demand.
The next generation 5G networks perform in a similar manner. The data and the control flow at each level. However, when and as necessary, the core level can help the cloudlet level or even the endpoint levels. The network is layered with specific form and function defined for each layer, but can flex to function differently as and when required. This is all done virtually and not physically. So, the 5G networks will be all software defined networks with hardware removed wherever possible. Now, some vendors are still trying to avoid an open architecture, standards based design in order to maintain market share and force their own products into the systems. However, that old way of building networks is failing to be embraced by the carriers who are now demanding a more universal design that allows them to tender for these systems and be able to interchange several vendors in each point of the design. The days of a single vendor solution are now behind us.
The 5G features and its usability are much beyond the expectation of a normal human being. With its ultra-high speed, it is potential enough to change the meaning of a cell phone usability.
With a huge array of innovative features, now your smart phone would be more parallel to the laptop. You can use broadband internet connection; other significant features that fascinate people are more gaming options, wider multimedia options, connectivity everywhere, zero latency, faster response time, and high quality sound and HD video can be transferred on other cell phone without compromising with the quality of audio and video.
The networks are different too. They are largely mesh networks and can still provide services similar to the historical star topological design, but now can move data traffic laterally as well as vertically. This will permit peer-to-peer traffic flows at lightning speeds and these lateral interactions will produce new capabilities and functionality never before imagined.
With the coming of 5G, more operators are interested in moving to flexible Cloud RAN (C-RAN) architectures. C-RAN enables operators to address different application requirements by locating storage and compute resources at the base of the cell site, at centralized hubs hundreds of kilometers away or anywhere in between. For example, operators can support latency-sensitive applications using Multi-access Edge Computing (MEC) data centers that are located closer to the serving cell site.
This flexibility is enabled through 5G functional splits that divide baseband processing among different elements, including the radio unit (RU), distributed unit (DU) and centralized unit (CU). These splits create two transport segments: fronthaul, between the RU and DU, and midhaul, between the DU and CU.
The RAN networks are offered in three different varieties: Fronthaul. Midhaul, and Backhaul.
Fronthaul – In essence, fronthaul is the connection between a new network architecture of centralized baseband controllers and remote standalone radio heads at cell sites.
Midhaul – The midhaul is the link between the fronthaul aggregation point and the backhaul network.
Backhaul – The mobile backhaul network connects radio access network air interfaces at the cell sites to the inner core network which ensures the network connectivity of the end user.
Enhance the network reliability and reduce the cost efficiency always been a major challenge for the cellular network operator and there is no magic solution to that demand. With the evolution of mobile network, the capacity requirement of the transport network from the core raises significantly. The major backhaul challenges that mobile network operator had to deal with up to 4G network includes capacity, availability, deployment cost, and long distance reach. But, 5G network will interconnect billions of new start devices with the numerous use cases and services, which will support machine-to-machine (M2M) services and Internet of Things (IoT) to the mobile network. These new smart devices will not only enhance the backhaul capacity requirement, but it will also add two additional challenges in the backhaul network: (a) ultra-low latency of ∼1 ms (round trip) connectivity requirements, and (b) denser small cell deployment.
RAN requirements drive the design of 5G transport in the access. However, the 5G transport network must also connect compute and storage clouds deployed at edge locations, such as central offices or aggregation points. In many cases, the operator is also thinking strategically about developing a metro edge using integrated packet-optical platforms to create a universal aggregation network that can serve many access types and customer segments. In this sense, the RAN transport decision is strategically important beyond 5G itself. When applied to 5G,Figure 9shows a scenario where the 5G core control plane is deployed (somewhat centrally), with UPF distributed to edge locations. In some cases, these same locations will also host CUs, DUs and services in various combinations. In this chart, RUs are shown in red connected over fronthaul to an integrated UPF/CU/DU located, for example, in a central office.The transport network should provide meshed connectivity to allow the operator the flexibility to deploy multiple models, and critically,to adopt new deployment models over time.
To stand up infrastructure is one thing; more important is to deliver the end-user service.In 5G the intent is to use network slices, configured to customer-specific and/or service-specific requirements, to provide an end-to-end service across domains: RAN, transport, core and cloud. A simple example might be a fixed wireless access slice on 5G routed discretely to, say, a mobile broadband slice. A more granular example might be a connected car, which plausibly needs slices for infotainment, telemetry, assisted driving, etc., each with different prioritization and reliability needs, and different business models. In each case, the operator must map slices in the 5G domain (using QoS and slice identifiers in the 5G RAN and core)into the transport network, and in some cases, the cloud platform,which hosts the application. Multi-domain orchestration is required to create and manage these services.
Important 5G Standards
5G is set to revolutionize the way we communicate, collaborate, and exchange data. The 5G New Radio (NR) system will support enhanced Mobile Broadband (eMBB), Ultra Reliable Low Latency Communications (URLLC), and massive Machine Type Communications (mMTC).
- Enhanced Mobile Broadband (eMBB). Similar to current services being offered for LTE, but faster, higher resolution, and more feature-rich. Examples include high resolution or 3D video and augmented reality applications. 5G is specified to go to 10Gbps for broadband access.
- Ultra-reliable and Low Latency Communications (URLLC). Services that require high reliability and some precision in real-time processing and response on the order of a millisecond. Examples here include autonomous driving, smart city, smart grid, and industrial IoT applications.
- Massive Machine Type Communications (mMTC). Services with a very large number of sensors sending information through IoT gateways to cloud applications and AI. Examples involve retail, smart city, agricultural IoT applications where many thousands of sensors (mMTC encompasses up to 1 million devices per square kilometer) may be providing information to cloud AI and machine learning applications to optimize city and retail planning, power optimization, or application of weed killers or insecticides.
5G NR is far more complex than previous generations of mobile networks and will still need to work together with current 4G LTE and WiFi radio access technologies (RATs), leading to challenges in network planning.
The 5G networks as specified by the 3GPP standards body will include:
- Massive MIMO
- Millimetre wave communications
- Ultra-dense small cell and heterogeneous network (HetNet) deployments
- New 5G services such as VR/AR.
The intelligence, which was traditionally centralized can now be pushed towards the edge so it is closer to the users. Some of the AI functions will remain centralized, but a lot of these resources can now live on edge servers at the network’s edge so performance will be greatly improved.
The data residency will be transformed as well. Data need not be centralized as in the past cellular generations. Since compute, storage, and processing can now reside on the network fabric, there may be no need to transit the data to the cloud. Data is expected to reside upon the network fabric. Data may never see the cloud, but live in cloudlets at the edge of the network. Derived data may journey to the cloud instead of the unprocessed mass volumes of raw data that was pushed upstream but was never processed or seen. The older model saw vast amounts of data stored in the cloud without any logic or application. Some estimates suggest that just 3% of all data shipped upstream to the cloud was used. The rest just took up storage and cost money to host. Now, we can make better use of data with 5G. While the old approach can still happen in 5G networks, the network congestion and cost concerns will soon force a more prudent and practical approach to data flows.
Time to Live
Data lifespan will change too. Now, we will only retain data for shorter time frames since it can be easily reproduced when needed. So the time to live for data will be adjusted to reflect the user and application needs. Derived data that is a summary of the raw data may be all that is needed for longer term storage.
Where we connect to the internet will also change. Since 5G will have intelligence at the edge, we can inject internet connections at the edge as well as at the central core network points. By injecting connections to the internet we lessen the burden on the core networks and the cloud, as well as the administration needs. Since 5G has the ability to scale so much larger compared to 4G, we must have this federated approach to the external internet connections too so flows are not delayed or blocked and processing can be accelerated.
With both large and small cells in the network, the radio access network or RAN is redesigned completely.
Two big shifts come into play for any organization developing a small cell strategy: a network design shift and an organizational shift.
Network design will involve moving from monolithic to multi-technology. To prepare for the future of 5G, an architecture that can seamlessly operate across multiple technology bases and between licensed and unlicensed spectrum is required. A nationwide macro environment contains thousands of cells to engineer, deploy, and maintain. A small cell environment has hundreds of thousands. In addition to shifting from a “macro towers only” mindset to a “connect anything” strategy, networks must operate both transparently and securely across licensed and unlicensed spectrum.
You should not underestimate the organizational shift required, either. Operational practices will need to shift from rigid to flexible and include dynamic toolsets. Light-touch “cookie cutter” processes will have to replace heavier, custom-engineered processes to control the cost and to speed up the delivery of those hundreds of thousands of cells. New ideas, tools, and organizational processes will be required to navigate the complexity of managing capacity and quality, even as the demand pattern remains essentially unknown and chaotic.
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About the Author:
Michael Martin has more than 35 years of experience in systems design for broadband networks, optical fibre, wireless, and digital communications technologies.
He is a business and technology consultant. Over the past 15 years with IBM, he has worked in the GBS Global Center of Competency for Energy and Utilities and the GTS Global Center of Excellence for Energy and Utilities. He is a founding partner and President of MICAN Communications and before that was President of Comlink Systems Limited and Ensat Broadcast Services, Inc., both divisions of Cygnal Technologies Corporation (CYN: TSX).
Martin currently serves on the Board of Directors for TeraGo Inc (TGO: TSX) and previously served on the Board of Directors for Avante Logixx Inc. (XX: TSX.V).
He has served as a Member, SCC ISO-IEC JTC 1/SC-41 – Internet of Things and related technologies, ISO – International Organization for Standardization, and as a member of the NIST SP 500-325 Fog Computing Conceptual Model, National Institute of Standards and Technology.
He served on the Board of Governors of the University of Ontario Institute of Technology (UOIT) [now OntarioTech University] and on the Board of Advisers of five different Colleges in Ontario. For 16 years he served on the Board of the Society of Motion Picture and Television Engineers (SMPTE), Toronto Section.
He holds three master’s degrees, in business (MBA), communication (MA), and education (MEd). As well, he has three undergraduate diplomas and five certifications in business, computer programming, internetworking, project management, media, photography, and communication technology. He has earned 15 badges in next generation MOOC continuous education in IoT, Cloud, AI and Cognitive systems, Blockchain, Agile, Big Data, Design Thinking, Security, and more.