Fibre for 5G and edge: Who does it and how to build it?

Opportunities for fibre network operators

4G/5G densification and the growth in edge end points will place fresh demands on telecoms network infrastructure to deliver high bandwidth connections to new locations. Many of these will be sites on the streets of urban centres without existing connections, where installation of new fibre cables is costly. This will require careful planning and optimum selection of existing infrastructure to minimise costs and strengthen the business cases for fibre deployment.

While much of the growth in deployment of small cells and edge end points will be on private sites, their deployment in public areas, in support of public network services, will pose specific challenges to providing the broad bandwidth connectivity required. This includes both backhaul from cell sites and edge end points to the fibre transport network, plus any fronthaul needs for new open RAN deployments, from baseband equipment to radio units and antennas. In almost all cases this will entail installing new fibre in areas where laying a new duct is at its most expensive, although in a few cases fixed point-to-point radio links could be deployed instead.

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Global deployments of small cells and non-telco edge end points
in public areas

Source: Small Cell Forum, STL research and analysis

In addition, operators of 5G small cells and public cloud edge sites will require access to fibre links for backhaul to their core networks to provide the high bandwidths required. In some cases, they may need multiple fibres, especially if diverse paths are needed for security and resilience purposes.

Many newer networks have been built for a specific purpose, such as residential or business FTTP. Others are trunk routes to connect large businesses and data centres, and may serve local, regional, national or international areas. In addition, changing regulations have encouraged the creation of new businesses such as neutral hosts (also called “open access” for wholesale fibre) and, as a result, the supply side of the market is composed of an increasing variety of players. If this pattern were to continue, then it would very likely prove uneconomic to build dedicated networks for some applications, such as small cell densification or some standalone edge applications.

However, provided build qualities meet the required standard and costs can be contained there is no reason why networks deployed to address one market cannot be extended and repurposed to serve others. For new fibre builds being planned, it is also important to consider these new FTTX opportunities upfront and in some detail, rather than as an afterthought or just a throw-away bullet point on investor slide-decks.  

This report looks at the opportunities these developments offer to fibre network operators and considers the business cases that need to be made. It looks at the means and scope for minimising costs necessary to profitably satisfy the widest range of needs.

The fibre market is changing

FTTH/P has been largely satisfied in many countries, and even in slower markets such as the UK and Germany, the bulk of the network is expected to be in place by 2025/6 for most urban premises, at least on the basis of “homes passed”, if not actually connected.

By contrast the requirement of higher bandwidth connectivity for mobile base stations being upgraded from 3G to 4G and 5G is current and ongoing. Demand for links to small cells needed to support 5G densification, standalone edge, and smart city applications is only just beginning to appear and is likely to develop significantly over the next 10 years or more. In future high speed broadband links will be required to support an increasing range of applications for different organisations: for example, autonomous and semi-autonomous vehicle (V2X) applications operated by government or city authorities.

Both densification and edge will need local connections for fronthaul and backhaul as well as longer connections to provide backhaul to the core network. Building from scratch is expensive owing to the high costs associated with digging in the public highway, especially in urban centres. Digging can be complex, depending on the surfaces and buried services encountered, and extensions after the initial main build can be very expensive.

Laying fibre and ducts are a long-term investment and can usually be amortised over 15 to 20 years.  Nevertheless, network operators need to be sure of a good return on their investment and therefore need to find ways to minimise costs while maximising revenues. In markets with multiple players, there will also be a desire by potential acquisition targets to underscore their valuations, by maximising their addressable market, while reducing any post-merger remedial or expansion costs. Good planning, including watching for new opportunities and trends and the smart use of existing assets to minimise costs, can help ensure this.

  • Serving multiple markets through good forecasting and planning can help maximise revenues.
  • Operators and others can make use of various infrastructure assets to reduce costs, including incumbents’ physical duct/pole infrastructure sewers, disused water and hydraulic pipes, neutral hosts’ networks, council ducts, and traffic management ducts. Obviously these will not extend everywhere that fibre is required, but can make a meaningful contribution in many situations.

The remaining sections of this report examine in more detail the specific opportunities offered to fixed network operators, by densification of mobile base stations and growth of edge computing. It covers:

  • Market demand, including drivers of demand, and end users’ and the industry’s needs and options
  • The changing supply side and regulation
  • Technologies, build options and costs
  • How to maximise revenues and returns on investment.

Table of Contents

  • Executive Summary
  • Introduction
    • The fibre market is changing
  • Small cell and edge: Demand
    • Demand for small cells
    • Demand for edge end points
  • Small cell and edge: Supply
    • The changing network supply structure
  • Build options
    • Pros and cons of seven building options
  • How do they compare on costs?
  • Impact of regulation and policy
  • How to mitigate unforeseen costs
  • The business case
  • Conclusions
  • Index

Related Research

 

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Open RAN: What should telcos do?

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Related webinar: Open RAN: What should telcos do?

In this webinar STL Partners addressed the three most important sub-components of Open RAN (open-RAN, vRAN and C-RAN) and how they interact to enable a new, virtualized, less vendor-dominated RAN ecosystem. The webinar covered:

* Why Open RAN matters – and why it will be about 4G (not 5G) in the short term
* Data-led overview of existing Open RAN initiatives and challenges
* Our recommended deployment strategies for operators
* What the vendors are up to – and how we expect that to change

Date: Tuesday 4th August 2020
Time: 4pm GMT

Access the video recording and presentation slides

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What is the open RAN and why does it matter?

The open RAN’ encompasses a group of technological approaches that are designed to make the radio access network (RAN) more cost effective and flexible. It involves a shift away from traditional, proprietary radio hardware and network architectures, driven by single vendors, towards new, virtualised platforms and a more open vendor ecosystem.

Legacy RAN: single-vendor and inflexible

The traditional, legacy radio access network (RAN) uses dedicated hardware to deliver the baseband function (modulation and management of the frequency range used for cellular network transmission), along with proprietary interfaces (typically based on the Common Public Radio Interface (CPRI) standard) for the fronthaul from the baseband unit (BBU) to the remote radio unit (RRU) at the top of the transmitter mast.

Figure 1: Legacy RAN architecture

Source: STL Partners

This means that, typically, telcos have needed to buy the baseband and the radio from a single vendor, with the market presently dominated largely by the ‘big three’ (Ericsson, Huawei and Nokia), together with a smaller market share for Samsung and ZTE.

The architecture of the legacy RAN – with BBUs typically but not always at every cell site – has many limitations:

  • It is resource-intensive and energy-inefficient – employing a mass of redundant equipment operating at well below capacity most of the time, while consuming a lot of power
  • It is expensive, as telcos are obliged to purchase and operate a large inventory of physical kit from a limited number of suppliers, which keeps the prices high
  • It is inflexible, as telcos are unable to deploy to new and varied sites – e.g. macro-cells, small cells and micro-cells with different radios and frequency ranges – in an agile and cost-effective manner
  • It is more costly to manage and maintain, as there is less automation and more physical kit to support, requiring personnel to be sent out to remote sites
  • It is not very programmable to support the varied frequency, latency and bandwidth demands of different services.

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Moving to the open RAN: C-RAN, vRAN and open-RAN

There are now many distinct technologies and standards emerging in the radio access space that involve a shift away from traditional, proprietary radio hardware and network architectures, driven by single vendors, towards new, virtualised platforms and a more open vendor ecosystem.

We have adopted ‘the open RAN’ as an umbrella term which encompasses all of these technologies. Together, they are expected to make the RAN more cost effective and flexible. The three most important sub-components of the open RAN are C-RAN, vRAN and open-RAN.

Centralised RAN (C-RAN), also known as cloud RAN, involves distributing and centralising the baseband functionality across different telco edge, aggregation and core locations, and in the telco cloud, so that baseband processing for multiple sites can be carried out in different locations, nearer or further to the end user.

This enables more effective control and programming of capacity, latency, spectrum usage and service quality, including in support of 5G core-enabled technologies and services such as network slicing, URLLC, etc. In particular, baseband functionality can be split between more centralised sites (central baseband units – CU) and more distributed sites (distributed unit – DU) in much the same way, and for a similar purpose, as the split between centralised control planes and distributed user planes in the mobile core, as illustrated below:

Figure 2: Centralised RAN (C-RAN) architecture

Cloud RAN architecture

Source: STL Partners

Virtual RAN (vRAN) involves virtualising (and now also containerising) the BBU so that it is run as software on generic hardware (General Purpose Processing – GPP) platforms. This enables the baseband software and hardware, and even different components of them, to be supplied by different vendors.

Figure 3: Virtual RAN (vRAN) architecture

vRAN architecture

Source: STL Partners

Open-RANnote the hyphenation – involves replacing the vendor-proprietary interfaces between the BBU and the RRU with open standards. This enables BBUs (and parts thereof) from one or multiple vendors to interoperate with radios from other vendors, resulting in a fully disaggregated RAN:

Figure 4: Open-RAN architecture

Open-RAN architecture

Source: STL Partners

 

RAN terminology: clearing up confusion

You will have noticed that the technologies above have similar-sounding names and overlapping definitions. To add to potential confusion, they are often deployed together.

Figure 5: The open RAN Venn – How C-RAN, vRAN and open-RAN fit together

Open-RAN venn: open-RAN inside vRAN inside C-RAN

Source: STL Partners

As the above diagram illustrates, all forms of the open RAN involve C-RAN, but only a subset of C-RAN involves virtualisation of the baseband function (vRAN); and only a subset of vRAN involves disaggregation of the BBU and RRU (open-RAN).

To help eliminate ambiguity we are adopting the typographical convention ‘open-RAN’ to convey the narrower meaning: disaggregation of the BBU and RRU facilitated by open interfaces. Similarly, where we are dealing with deployments or architectures that involve vRAN and / or cloud RAN but not open-RAN in the narrower sense, we refer to those examples as ‘vRAN’ or ‘C-RAN’ as appropriate.

In the coming pages, we will investigate why open RAN matters, what telcos are doing about it – and what they should do next.

Table of contents

  • Executive summary
  • What is the open RAN and why does it matter?
    • Legacy RAN: single-vendor and inflexible
    • The open RAN: disaggregated and flexible
    • Terminology, initiatives & standards: clearing up confusion
  • What are the opportunities for open RAN?
    • Deployment in macro networks
    • Deployment in greenfield networks
    • Deployment in geographically-dispersed/under-served areas
    • Deployment to support consolidation of radio generations
    • Deployment to support capacity and coverage build-out
    • Deployment to support private and neutral host networks
  • How have operators deployed open RAN?
    • What are the operators doing?
    • How successful have deployments been?
  • How are vendors approaching open RAN?
    • Challenger RAN vendors: pushing for a revolution
    • Incumbent RAN vendors: resisting the open RAN
    • Are incumbent vendors taking the right approach?
  • How should operators do open RAN?
    • Step 1: Define the roadmap
    • Step 2: Implement
    • Step 3: Measure success
  • Conclusions
    • What next?

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