Delivering ultra-broadband connectivity in rail public ... · 2 Strategic White Paper Delivering...

1 Strategic White PaperDelivering ultra-broadband connectivity in rail public transport

Delivering ultra-broadband connectivity in rail public transportSolutions and business models for improving passenger experience and generating new revenue

Strategic White Paper

Today’s rail passengers increasingly demand seamless connectivity while traveling. They not only expect to be transported comfortably and securely, but also wish to be informed, entertained and remain productive. This paper covers both the business and technical considerations for delivering Wi-Fi® and 3G/4G cellular services to passengers in a railway system – at stations, and on tracks above and below ground. It describes the business models and financial case, as well as the technical architecture for providing services not only to the stations and platforms, but also on moving trains above and below ground. It offers go-forward considerations for railways operators looking to gain competitive advantage in their public transport service offerings.


Contents

Introduction 3

Ultra-broadband demand and challenges 3 Today’s issues 4

The solution 6

LTE as a platform for rail communications 6

High-level architecture for rail ultra-broadband 7

Ultra-broadband business models for metro rail 9

The stakeholders 9

1. “Duplicated” model 9

2. “Shared” model 11

3. “Wholesaling” model 12

4. “Exclusive” model 13

The business case 14

Moving forward with ultra-broadband 17

Acronyms 18

Contacts 19


IntroductionRail passengers are demanding customers. Today they expect not only to be transported comfortably and securely, but also to be informed, entertained and connected to their families, friends and business colleagues while they are in transit. They see their journeys as an extension of their office time, and they do not expect their social lives to be put on hold while they are taking the metro or train. With the International Association of Public Transport (UITP) measuring more than 21 billion passenger trips in the world in 2014 along metro rail lines, these heightened expectations pose big opportunities and challenges for the rail public transport industry.

Many rail infrastructure managers recognize that broadband public communications services can improve the passenger experience, generate new profitable businesses and create loyal customers. But what is the business case? What are the best solutions and business models that will maximize the quality of the service delivered, while still guaranteeing the sustainability of the investments?

Several solutions can deliver an advanced level of on-board connectivity to passengers. They have varying complexity, cost efficiency and performance levels. The optimal solution for any rail network depends on a host of internal and external factors, including its strategic goals, the priorities of stakeholders, its existing communications infrastructure, its physical assets and availability of spectrum.

Ultra-broadband demand and challenges Rail passengers around the world increasingly expect fast, reliable broadband services – similar to those found at home or at the office – while in the train or station. This demand is growing, driven by an increase in public transport ridership, competition among different means of transport, and travelers’ nearly universal use of smartphones and connected devices.

Research has shown that mobile apps are improving the journey experience. Passengers can plan their trips better— reducing wait times for trains, and can entertain themselves during any delays that do occur. This has had a significant impact on mitigating perceived and actual waiting times, a real Achilles’ heel for transport operators.

But with increasing numbers of people using connected devices in public transport, the pressure on existing urban communications networks is immense, and the exceptional density of “user per cell” in a mass transit system (similar to that in a stadium or a shopping mall) brings with it an enormous strain on every radio network’s capacity planning, especially when combined with the element of mobility handover. Travelers say they


currently experience slow download speeds or, even worse, no signal at all, in underground rail facilities. Even when they have a 3G or 4G signal, the performance of the network is poor, only adding to the frustration of the journey.

Today’s issuesMost of the existing cellular networks used in public transport are those of mobile network operators (MNOs). These networks are not designed to provide connectivity optimized for public transport. Neither are they suitable for large numbers of passengers wishing to access mobile data services at the same time, especially in a train moving rapidly underground. Even for lines at grade or at elevated levels, homogeneous coverage for continuous connectivity in moving trains is rarely possible, simply because the radio cells are not deployed along the tracks. This often leads to random loss of signal, or in the best case, to throughput that is highly erratic, especially at the cell edge. (See Figure 1.)

Figure 1. Use of existing MNOs’ networks in public transport

No coverageMNO 1

Bettercell

MNO 2

MNO 3MNO 1

Throughput versus track locationMNO 3

Cell overloaded

MNO 1


Heavy vehicular penetration loss and shading usually mean that the MNO’s signal is weak. A loss of more than 20 dB is quite common in highly insulated cars. This problem is well known throughout existing public cellular networks. In these instances, passenger experience suffers with poor handover and slow bit rates.

To address this issue, some public transport operators have deployed Wi-Fi® connectivity services inside the trains. This relay mode is delivered by an on-board unit (OBU) connected to and aggregating several public mobile networks in order to increase the throughput. (See Figure 2.)

Figure 2. Direct transmission mode versus relay mode via OBU

This solution still has many limitations in terms of coverage, capacity and performance. Although the OBU may detect varying signals from nearby MNO networks, those are not usually optimized for trackside coverage and the sudden surge of capacity demand when a train passes by. Due to architectural limitations, the OBU also may have difficulty in selecting the best MNO network(s) for an optimal connection while the train speeds past. In addition, a Wi-Fi service on board usually requires passengers to opt in, adding complexity and frustration for end users. This is why many initiatives for providing on-board connectivity with or without OBUs have led to low return on investment and, in some cases, to bad customer experience.

Throughput versus track location

No coverageMNO 1

Bettercell

MNO 2

MNO 3MNO 1

MNO 3Cell overloaded

MNO 1

With OBU

OBU


The solutionRail operators seeking to improve their passengers’ experiences require a ground-to-train radio network optimized and dedicated for the public transport infrastructure. It must offer the best coverage along the tracks in tunnels, at grade and along elevated segments. It also must be able to provide the scalability required in crowded urban environments, especially at rush hours, with deterministic behavior at the cell edges for fast and efficient handovers while the train is moving full speed.

Operators can integrate an on-board infrastructure with these attributes to overcome the penetration loss in the carriage. In addition to Wi-Fi, this can employ 3G or 4G Long Term Evolution (LTE) in small cells that connect seamlessly with mobile phones with no opt-in required. (See Figure 3.) The same dedicated public transport radio network can also provide coverage at stations, on platforms, in concourses and in railway offices.

Figure 3. Dedicated ground-to-train radio network with OBU and small cells

LTE as a platform for rail communicationsLTE, also called 4G or 4G LTE, is the fourth generation of mobile communication technology, and is the optimal platform for building a dedicated ground-to-train radio network. Its primary characteristics are high speed, high security and high bandwidth capacity. It offers several key advantages for the railway industry:

• LTE implements state-of-the-art digital communication and modulation techniques (OFDMA, MIMO, turbo coding, adaptive modulation and coding), resulting in high spectral efficiency. This allows transmission speeds of up to 150 Mb/s over the air (downlink). This level of throughput is a key parameter for assuring that passengers have good experience when surfing on the Internet.

OBU

SmallcellsMNO1, 2, 3

Throughput versus track location


• LTE is based on IP. This means that operators can fully rationalize all communication networks into a single mobile LTE and fixed IP/Multiprotocol Label Switching (IP/MPLS) network. This leads to substantial savings on network design, management and maintenance.

• LTE has low latency (down to 10 ms), meaning that it can support critical, time-sensitive applications and provide high levels of quality of service management. Bit rate, latency, maximum packet loss, priority and all other key transmission parameters can be set up for each application and each user. These settings also can easily be changed as required, for example in support of incident management.

• LTE is a flexible technology that can be deployed in many different frequency bands, and can accommodate different channel bandwidths.

• LTE networks are fully secured and resilient. The LTE standard includes multiple features related to encryption and authentication, rendering this technology secure by default. In addition, when properly designed, an LTE network has several mechanisms for auto-reconfiguration in case of network failure — vital for an always-on railway communication network.

These attributes make LTE superior for building a radio network able to support passenger connectivity needs, along with mission-critical operational applications such as train signaling, closed-circuit television (CCTV) on-board and emergency communications — all on a single converged IP network.

High-level architecture for rail ultra-broadbandThe high-level architecture for rail-optimized ultra-broadband is summarized in Figure 4. This solution is composed of different elements and layers that need to be well integrated to give the best possible performance level at the most effective cost.

Figure 4. High-level architecture for rail-optimized ultra-broadband

Macro cell

Management HSS

PGW

Small cell WLAN AP DRSDAS

Indoor/underground stationOutdoor section

LTE +WLANRAN

Core

WLANcore Applications

Tunnel

Small cellsMNO 1, 2, 3

SGW

PCRF MMEIP/MPLS aggregation and access

WLAN controller AAA CDN Application servers

Internet

OBU


The train or carriage hosts the OBU and 3G or 4G small cells described previously. Depending on the business model, one small cell per MNO in the train’s service area is recommended, as passengers may use different providers.

The next level of architecture is the radio access network (RAN), which resides in stations, on platforms, at circulation levels, in offices and along the tracks in tunnels, at grade or on elevated segments. It is composed of a combination of macro cells, small cells, a distributed radio system (DRS) and an active and/or passive distributed antenna system (DAS), which provide the optimum coverage everywhere.

In tunnels, where space and access are limited, the radio signal from a macro cell is usually spread using either a DRS with passive leaky cables or an active DAS. Outside, at up-grade or elevated levels, operators normally use classical macro cell solutions with masts and antennas. On platforms, they employ similar solutions.

For the stations, circulation levels and offices, operators can replace or complement macro cells with DRS and DAS solutions with wireless local area network (WLAN) access points and cellular small cells. In these very crowded environments, small cells are an excellent way to increase the capacity and coverage of the radio network.

This RAN is backhauled by an access and aggregation wired network. This usually employs IP/MPLS technology to connect the radio base stations and WLAN access points to the core of the radio network. (The WLAN access points are also connected to the WLAN controllers so that the rail operator can offer Wi-Fi service to passengers.) The core network is made of several building blocks, including a home subscriber server (HSS) to manage the passenger subscribers, a mobility management entity (MME) for tracking and paging, and a Policy and Charging Rules Function (PCRF) for accessing subscriber databases and other specialized operations. A serving gateway (SGW) supports handover between radio cells and manages interconnections with the other data networks through a packet data network gateway (PGW).

This access and aggregation network connects the entire system to the data center, which hosts all of the applications servers. These include the authentication, authorization and accounting (AAA) servers to optimize the delivery of web and multimedia contents in a content delivery network (CDN), and other application servers.


Ultra-broadband business models for metro railRail operators wishing to deploy an ultra-broadband network can choose from several business models. Finding the best fit depends on the priorities of stakeholders, the availability of spectrum, the services provided by regional MNOs and the longer term strategic goals of each company. This section uses a simplified framework to analyze four of the most common business models, with their respective advantages and challenges.

The stakeholdersTwo or three categories of stakeholders typically will play major roles in ultra-broadband network planning for metropolitan rail lines:

• The local or regional Public Transportation Authority (PTA) may own the railway’s buildings, stations, tracks, technical rooms, HVAC systems, DAS, data centers and control centers. It also may partially or totally own the operational radio network and its management, and perhaps even licensed spectrum for operating its own RAN.

• MNOs usually own licensed spectrum, their core networks and data centers. However, they do not have the technical rooms nor the DAS to deploy a public transport radio network along the railway and in tunnels.

• Regional public safety or governmental agencies also can be stakeholders if the public transport radio network has to carry their operational and emergency voice and data traffic.

1. “Duplicated” modelIn this model, the PTA grants to MNOs (and public safety agencies) the right to deploy their own RAN infrastructure in the premises of the transport operator according to their own design practices. This model is called “duplicated” simply because if there are four MNOs in the service area, in principal the public transport RAN has to be duplicated four times.

This model has advantages for the PTA: it does not require a licensed frequency for the radio network and does not have to manage and maintain the radio networks. The investment for the PTA is limited in this model, and so is the potential revenue (considering site and space rental for MNOs).


However this model requires duplicated radio equipment and infrastructures, significant space in technical rooms and duplicated maintenance – a challenge for multiple PTAs competing for limited time slots during low traffic periods. For underground metro lines, installation of several antennas, equipment and cables from several MNOs along the tracks can be extremely challenging given the limited space in tunnels. RF interferences between the various MNOs networks also may be an issue, especially in confined areas.

The business case for MNOs might not be attractive, and therefore deployment might not take place or might be limited to outdoor rail tracks. Additionally, duplicated MNO radio networks cannot be used by the PTA to support its operational applications and mission-critical services such as train signaling, CCTV and passenger information system (PIS).

Examples of the Duplicated model are Transport for London (TfL) in stations and Paris Metro (RATP) in stations.

Table 1 provides a summary of the advantages and disadvantages of this type of model.

Table 1. Advantages and challenges of the Duplicated model

ADVANTAGES CHALLENGES

No need to license spectrum Requires duplicated radio equipment and infrastructures, with limited space and challenging maintenance availability

No need to manage radio networks Possible RF interference between multiple MNOs

Neutral position toward MNO Cannot be used by PTA to support mission-critical services and operations

Minimal burden in providing third-party communications

Weaker business case for MNO may limit deployment

Site support (e.g., site access and HVAC) Space/power constraints could lead to substantial civil works

Limited investment, except for project management and setup

Third parties without good railway knowledge could cause issues in the partnership

Minimal technical standards/refs for assuring equipment co-location

Some limited fee can be charged to the MNO for site rental and setup cost


2. “Shared” modelIn this model, the PTA deploys (or already owns) one or several active and wideband (typically 380 MHz – 2700 MHz) DAS systems inside the tunnels, along the tracks, in stations and on platforms. The PTA grants one or more MNOs access to this infrastructure in order to spread radio signals throughout the system. The MNO’s radio base stations are hosted in technical rooms at PTA sites. This model can also be called the “Hosting” model.

This model offers lower investments in cabling, leaky cables and antennas, since the DAS is mutualized across all the MNOs. This eases the maintenance of infrastructure deployed in the tunnels and along the tracks. However, even if a part of the RAN is mutualized, the biggest part (the base stations) is still duplicated, making this model not fully optimized in terms of capital expenditures (CAPEX), energy consumption and maintenance. As with the Duplicated model, the PTA cannot leverage these radio networks to support its own operational and mission-critical applications.

Examples of the Shared model are Paris Metro (RATP), Toronto Metro, Eurotunnel, Gotthard tunnel and NYC Subway with Transit Wireless.


Table 2. Advantages and challenges of the Shared model


No need to license spectrum Requires duplicated base stations, with limited space and challenging maintenance availability

Reduces investment since DAS can be used by multiple MNOs

Base stations still must be duplicated

Simpler maintenance because of shared DAS infrastructure

Cannot be used by PTA to support operations and mission-critical services

More cost-efficient for wide deployment through rationalization of DAS systems

Higher CAPEX investment for PTA

More risk control over introducing MNOs/PTA

More management at planning stage: Requires gathering, rationalization and compromises

Prospect of railway communications asset monetization

RF field experience

Less intrusive expansion possible when introducing new service providers

Integration expertise for managing MNOs/PTA connectivity


3. “Wholesaling” model

In this model, the PTA owns licensed spectrum and builds its own LTE RAN, composed of a combination of macro cells, small cells, DRS systems and a passive DAS. This RAN is rented (“wholesaled”) to MNOs, each of which signs a roaming agreement with the PTA. Each MNO connects its respective core network to this single RAN infrastructure. There are many advantages to this solution. There is no need to deploy a complex and costly active DAS infrastructure to cover the tunnels, stations and platforms. The DRS architecture can greatly simplify and reduce the cost of deployment, since it allows decoupling the radio base station with the remote radio head (RRH). The RRH can be placed several hundred meters away from the radio base station, where it is directly connected to a passive leaky cable.

A DRS architecture with passive DAS reduces space requirements. A typical active DAS system introduces a bulky point of interconnection panel (filters and attenuators), and complex multiple-stage analog-to-digital conversion processing that requires a significant amount of space in each hosting facility. With DRS, the active radio elements are distributed in small station telecom rooms, or in protected recess areas in tunnels. Only the baseband units, which provide the modem processing function, and the core networks are centralized in the technical rooms or data centers.

A DRS solution improves the RF performance of the whole system, as it does not suffer from the typical DAS signal degradation problems. The PTA can agree to share the RAN and in-building solution, which will achieve the best cost efficiency when public safety adopts LTE. The PTA can also use this dedicated radio network for operational and mission-critical applications required to operate a train (on-board CCTV, PIS, private mobile radio, signaling, emergency communications, etc.). This will dramatically reduce the cost of operations.

In this model, the PTA essentially acts as an MNO. The drawback is that it requires a licensed spectrum and skills for the PTA to manage such a dedicated network. In the event that the PTA cannot obtain the spectrum license, there is always the possibility to “rent” it from one of the MNOs, limiting the potential revenues.

An example of the Wholesaling model is the Hong Kong Metro (MTR) for its transmission network.



Table 3. Advantages and challenges of the Wholesaling model

4. “Exclusive” model

In this model, the PTA signs an exclusive agreement with one MNO. This MNO gets the exclusivity to deploy its own radio network in stations, on platforms, in tunnels and elsewhere. The MNO signs roaming agreements with other MNOs. Advantages include a neutral host with multi-operator support, optimized coverage and capacity, and the use of well-understood technology.

This model has the advantage of simplicity, the capability to carry operational communications along with public services, and multiple revenue opportunities. However, it can create competitive distortions between participating MNOs. An example of the Exclusive model is Transport for London (TfL); Wi-Fi only, with Virgin Media.


Table 4. Advantages and challenges of the Exclusive model


DRS greatly simplifies and reduces the cost of the network deployment

Requires more CAPEX than Duplicated or Shared models

PTA can also deploy its own core network to fully leverage this dedicated radio network for transporting the operational and mission-critical applications

Requires skilled personnel to manage network

When used for both passengers and operations, CAPEX/OPEX is extremely low

Rented spectrum option will raise costs

DRS solution also improves the RF performance of the whole system

Requires national roaming implementation

Maximize synergy between wide range of railway wireless communications requirements (near-term and long-term) with shared systems

Requires PTA to acquire core wireless expertise (in-house or contracted out)


Most simple approach Limited revenue

Requires minimal investment in equipment, technical expertise and maintenance

Can create competitive distortion between participating MNOs

Can minimize deployment time Partner MNO must sign roaming agreements with other MNOs

14

Table 5 summarizes the scope of responsibilities for each business model, and who owns which key components.

Table 5. Ownership of key components in rail ultra-broadband modelsModels Sites Spectrum DAS/DRS RAN Core

Duplicated PTA MNOs MNOs MNOs MNOs

Shared PTA MNOs PTA MNOs MNOs

Wholesaling PTA PTA PTA PTA MNOs, PTA

Exclusive PTA MNO MNO MNO MNO

Table 6 summarizes the advantages and challenges of the various models.

Table 6. Summary of comparative advantages and challenges for ultra-broadband business models. Models Coverage

performanceCAPEX/OPEX*

Usage Revenue for PTA

Skills required from PTA

Duplicated ++ High Passengers + Very low

Shared + High Passengers ++ Low

Wholesaling +++ Low, very low Passengers + operations

+++ High

Exclusive +++ Low Passengers + Low

*Cumulative CAPEX/OPEX for PTA and MNOs. When the radio network is also used for the operation of the trains, the CAPEX/OPEX becomes extremely low

The business case The following business scenario assumes the Wholesaling model. It uses a configuration comprising 20 underground stations, with 1 kilometer of dual tunnel between each one. The predicted communications usage grows to 20,000 connected passengers per working day over a period of 5 years. It assumes that each user of the system remains connected for 20 minutes, and uses an average of 1 Mb/s of data during that time. The proportion of capital costs for this configuration are shown in Figure 5, with the biggest element being the cellular equipment with its associated DAS and RHH cabling in the stations and tunnels.

Strategic White PaperDelivering ultra-broadband connectivity in rail public transport


Figure 5. Capital costs for sample configuration

Operation of this system comprises two elements: the personnel to manage and maintain it, and the cost of equipment maintenance and repair. Figure 6 shows the proportions of these costs over a 5-year period.

Figure 6. Proportions of costs over a 5-year period

Staff costs Maintenance costs

75%

25%

0%

On-board infrastructureCore equipments RAN equipments

79%

21%


The overall expenditure over 10 years, including interest payments on the financing required to cover the initial capital expenditure, is shown in Figure 7.

Figure 7. Overall expenditure over 10 years

This leads to an overall cash flow as illustrated in Figure 8.

Figure 8. Cash flow for sample configuration

In this example, positive cash flow is achieved rapidly within 12 months. Positive cumulative cash flow is achieved after 52 months (just over 4 years), with a net present value (NPV) over 10 years of 20.2 million United States dollars and an internal rate of return of 26.2 percent.

As with all business cases, it is important to understand the sensitivities – which variables have the most potential to affect the project. Figure 9 illustrates this sensitivity, highlighting the seven most significant costs or revenues for this particular business case. It shows the impact on the NPV when adjusting each of the key variables by ±15 percent. In this example, the largest impact comes from the charges made to the MNOs for leasing capacity.

OPEXInterest payments Capital investment

14%

33%

53%

0 1 2 3 4 5

Year

6 7 8 9

Capital Investment OPEX Cost of goods sold Gross revenue Free cash flow Cumulative free cash flow


Figure 9. Sample project sensitivities

As illustrated by this example, a profitable business case is readily feasible for the type of activities described in this paper. The major revenue source is from leasing capacity to the MNOs in the tunnels and on the underground stations, though the importance of providing public ultra-broadband connectivity must not be underestimated. Although it brings less direct revenue, it is key to attracting and retaining passengers.

Moving forward with ultra-broadbandToday’s metro rail passengers expect to be informed, entertained and connected to their families, friends and business colleagues while they are in transit, posing challenges for public transit rail operators. The technical solutions available today provide a way forward for rail operators. Leveraging LTE and IP/MPLS as the technology platform, they can support a unified network with both system-wide passenger ultra-broadband connectivity and mission-critical operational communications.

Several innovations are foreseen on the horizon that will enhance the passenger experience and that will open the door to new capabilities. These include seamless hand-over between Wi-Fi and LTE networks for data and even voice, Wireless Unified Networks to blend the capacity of both Wi-Fi and LTE for higher throughputs, and the evolution of LTE to 5G. The solutions outlined in this white paper offer viable financial scenarios and a technology base that is ready for the next wave of advanced technology and the additional innovations still to come.

-15 -10 -5

Impact on NPV (’000,000)

0 5 10 15

15% higher 15% lower

MNO cellular revenue

Staff costs

Cellular equipment

Average duration of session

Metro customers per day

Annual growth rate

Loan interest rate


3G The third generation of mobile telecommunications technology, based on a set of standards used for mobile devices and infra structure

3GPP 3rd Generation Partnership Project

4G The fourth generation of mobile telecommunications technology, based on a set of standards used for mobile devices and infrastructure

5G The fifth generation of mobile telecommunications technology

AAA authentication, authorization and accounting

CAPEX capital expenditures

CCTV closed circuit television

CDN content delivery network. A set of distributed servers across a network to ease the broadcast of content

DL downlink

DAS distributed antenna system

DRS distributed radio system

HSS home subscriber server

HVAC heating, ventilation and air conditioning

IPTV IP television

LTE Long Term Evolution, a standard for high-speed mobile data and voice services

MME mobility management entity

MNO mobile network operator

MPLS Multiprotocol Label Switching

MIMO multiple-input multiple-output. A method for multiplying radio capacity using multiple transmit and receive antennas

MVNO mobile virtual network operator

NPV net present value

OFDMA Orthogonal Frequency-Division Multiple Access

Acronyms

OBU on-board unit

OPEX operating expenditures

PCRF Policy and Charging Rules Function

PGW packet data network gateway

PIS passenger information systems

PTA Public Transportation Authority

RAN radio access network

RRH remote radio head. A radio system that connects to a remote radio transceiver

SGW serving gateway. The gateway that terminates the interface toward e-nodeB

UITP International Association of Public Transport (from the French)

WLAN wireless local area network. Also called Wi-Fi

ContactsU.S. and Canada: +1 866-231-0264 (M-F 8:00 a.m. - 5:00 p.m. Eastern). Europe: +44 560 301 5799 (M-F 8:00 a.m. - 4:00 p.m. GMT)

Related web site: http://networks.nokia.com/portfolio/industries/railways

Nokia is a registered trademark of Nokia Corporation. Other product and company names mentioned herein may be trademarks or trade names of their respective owners.

Nokia Oyj Karaportti 3 FI-02610 Espoo Finland Tel. +358 (0) 10 44 88 000

Product code: PR1602018301EN

nokia.com© Nokia 2016

http://networks.nokia.com/portfolio/industries/railways

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