Over the past several years, 5G has transformed from a concept spoken about at conferences to a reality with numerous deployments being rolled out across the globe. The technology will completely change the communications landscape, paving the way for new revenues and services that were not previously possible. By the end of 2020, it is predicted there will be more than 258 million 5G connections, and by 2023 more than 1 billion connections worldwide.

For operators, the growth in 5G connectivity has the potential to be extremely lucrative. In 2020, worldwide 5G wireless network infrastructure revenue will reach $4.2 billion, an 89% increase from 2019 revenue of $2.2 billion, according to Gartner, Inc. This is because as 5G becomes more available to consumers and businesses, IoT products that require this level of connectivity will grow in popularity, such as autonomous cars and devices for smart cities. The low latency and high capacity will not only enable new devices to the market but also enhance existing service value and revenues.

However, while the benefits may be innumerable, so are the challenges that come with deploying 5G. Network traffic is already growing, but the introduction of 5G will create a massive surge as new applications and services come to the market. Healthcare, education and many other industries are likely to take advantage of the numerous benefits the latest technology can bring – all putting increasing pressure on existing infrastructure. Considerable changes must be made to networks to keep up with this demand, with the transport network being of utmost importance.

New requirements

To deliver a global mass rollout of 5G operators, a massive enhancement of the transport network is needed. This is a result of the significant increase in capacity 5G will bring – including an estimated doubling of radio sites deployed and a new architecture with new Radio Access Network (RAN) and Core interfaces. These new architectures and new interfaces each have specific criteria that must be met.

At the same time, new radio access technologies such as mmWave and Massive MIMO will impose higher capacity, lower latency, and new traffic flows such as fronthaul and mid-haul, along with stricter timing and synchronization requirements. This will further add to the strain on the transport network, while new services are expected to require the network to deliver tighter delay and loss bounds.

Finally, disaggregation in both the RAN and core network is expected to have a further effect on the transport network architecture.

The road to success

To meet the demands of 5G, these emerging complexities of 5G networks require intelligent, automated coordination between RAN, mobile core networks and the underlying transport network. In addition to the required upgrade of legacy transport systems, backhaul systems must meet a suite of new demands to ensure superior RAN performance and maintain the low total cost of ownership. 5G backhaul systems need to address increased capacity and increased interface density requirements. A typical 4G distributed RAN site, with 5G New Radio, added, will require up to 10 Gbps backhaul capacity. Spectrum sharing solutions will drive demand for many 10GE ports to deliver RAN coordination. 5G New Radio will also use the new enhanced common public radio interface (eCPRI) with up to 25 Gbps connections. Consequently, 5G backhaul baseband interfaces will need 10 Gbps capacity and need to scale efficiently up to 100GE.

All of this means that operators need a Transport Network Architecture for 5G that will enable them to effectively provide the required capabilities in a practical and effective manner. In order to achieve this, operators should look to take advantage of the many technological developments that have occurred in transport networks since the rollout of LTE many years ago. These include IPv6, MPLS and other modern technologies.

The role of standards

As with any new technology or architecture, leveraging these technologies does not come without risk – which is precisely why Broadband Forum members are working on a new 5G Transport Architecture and Requirements specification.

Broadband Forum’s 5G Reference Architecture

Based on the thorough work that has been done at 3GPP and other places to develop standards for 5G, the reference architecture will introduce the use of new transport and routing technologies and apply these to the 5G split RAN architecture. The standard will leverage IPv6, segment routing, MPLS, Ethernet VPN (EVPN) and other technologies to enable effective and scalable transport networks to support operator 5G deployments. This will be in conjunction with LTE and 4G operations, allowing operators to protect their existing investments by using their existing networks and enhancing and migrating them rather than completely replacing them.

How the reference architecture will map onto existing networks

This is in addition to Broadband Forum’s other 5G initiatives which include a joint Fixed Mobile Convergence project with 3GPP and a specification for a 5G Access Gateway Function (AGF) that adapts fixed access onto the 5G core. Specifications for measuring, analyzing and scaling the capacity and Quality of Service of the transport networks noted above are also underway in the Forum’s Access and Transport Architecture (ATA) Work Area. These overcome some of the shortcomings of today’s capacity-centric and node-centric network equipment and analysis.

A 5G future

As 5G services become more available, an enhanced transport network will be essential to effectively handle the rapid growth in network traffic. With the industry collaboration that Broadband Forum is enabling, the transport network will be perfectly placed to meet the challenges 5G will bring and keep the unprecedented amount of traffic flowing.

About the Author

Robin Mersh joined the Broadband Forum as Chief Operating Officer in July 2006, and was promoted to Chief Executive Officer in July 2010. Mersh has authored many articles and has spoken at and chaired many broadband industry conferences and exhibitions. He has worked in the telecommunications industry for over 18 years, starting at Cable & Wireless and then moving on to BT before meeting his wife and moving to the US in 1999.

Mersh has worked in business development and alliance management for various OSS software companies in the United States, mainly in network and service provisioning and activation, where he negotiated and managed several large OEM agreements. He is originally from Cambridge in the United Kingdom. He received a Bachelor of Arts degree with honors from Queen Mary and Westfield College, University of London in 1992.