Trackside vs. LTE aggregation: insights for the right choice

Maxima is the global leader in monetising Wi-Fi networks and a pioneer in providing. If you choose the right technology and monetisation system there are major opportunities for business growth through higher fares and premium services.

Any transport operator willing to introduce passenger Wi-Fi faces the choice of backhaul technology. Here are options that should be considered:

01.
Cellular (e.g. LTE), public or private
02.
Track-side radio in 5GHz Wi-Fi bands
03.
Track-side radio in high-frequency bands, usually 60-70Ghz, depending on local regulations
04.
Satellite

Each one has its limitations, advantages and dis-advantages. We see a lot of cases when the choice is made without even considering alternatives thoroughly and here it’s rarely made with deep understanding of future monetisation limitations.

Let’s go through these options and highlight key points that might affect the choice.

Cellular backhaul

One public LTE network

It’s usually the cheapest option when decent coverage is in place and it’s possible to buy enough traffic at fare rate. Equipment can be purchased from $50 (SOHO) to $500K (ruggedized and compliant to international transport standards). It’s possible to run the same monetisation schemes using both, so equipment choice might be affected by maintenance considerations and transportation operator’s requirements.

Prerequisites will be:

Almost 100% cell networks coverage
Fair mobile data prices
External funding, at least partial
Moderate or absent service level (especially bandwidth) requirements

Monetisation will be limited to Advertising and Static content, including native articles

Average throughput is from 2 to 20 Mbps. The best performance will be achieved if the MNO will set highest priority for these sim-cards in network configuration.

One more specific point here is that the same bandwidth will be available on personal devices, so the target audience will be limited to lower income passengers and international tourists.

This is why this approach is mostly used at city over ground transportation and tourist buses. For instance,
it’s used in Moscow Transport Wi-Fi.

One private LTE network

This option is different by two parameters: bandwidth and coverage are guaranteed by design,additional CAPEX and OPEX are required and are quite high.

Bandwidth here is basically all bandwidth available in an LTE network with given spectrum (let’s assume 80MHz is available) shared by all «users» in the area. Resulting average speed may be up to 100 Mbps per vehicle.

Service of such quality can be easily monetised with video ads and video content in addition to the above mentioned static advertising, but unlikely all of these will pay back for the complete infrastructure.

This is a good option for citywide services, where Transport Wi-Fi is just one of many.

We haven’t seen this model outside subways at all but would assume it’s possible to deploy in Middle East capitals willing to pioneer Smart Cities.

One of examples in subways — the first on-train Wi-Fi network in Seoul Metro.

LTE aggregation

By aggregating two or many LTE channels onboard it’s possible to increase stability and speed of passenger Wi-Fi. Equipment allowing aggregation is more expensive — it costs from $100 to $15K, depending on industrial protection, functionality, number of sim-cards and support. We’d suggest a ballpark $500 for 2-sim solution for buses and trams and $5K for 4+ sim-cards on trains. If it’s planned to provide onboard media content, add $5-10K more.

Available average throughput may vary from 30 to 100 Mbps, but it’s unlikely possible to agree the highest priority for public Wi-Fi sim-cards with all mobile data providers — such customers are a nightmare comparing to any B2C customer, both from usage pattern and requirements standpoints. So, the service quality usually declines in rush hours.

This approach is probably the most balanced and widely spread, especially on railways. And this is why it’s somewhat default for all over ground transport.

Railways, however, should at least consider another option — own trackside radio network.

Trackside radio networks (TSN)

5Ghz TSN

This technology is usually based on Wi-Fi chipsets with proprietary modulation protocols to support required features: mobility with seamless hand-over and/or aggregation of two active units, lower latency, custom MIMO configuration, network synchronization, etc.

Thus, bandwidth here is limited to 5GHz Wi-Fi bands — up to 160MHz with aggregation or 80MHz without it. As a result, today it’s possible to achieve average throughput of 500 Mbps per train, and in some cases — up to 1Gbps when aggregating bands and 2 active mobile units in both head cars of a train.

More details on TSN

Usually this is the main option for environments with poor cellular connectivity — subways and rural areas.

Prerequisites for choosing

Poor cellular connectivity
Ability to install poles or use existing elevated constructions (2-6m high) to place base stations and antennas
Available sources of power
Ability to install or use existing fiber
Enough space in tunnels, if it’s for subway trains
High requirements for quality of experience (QoE).

Equipment costs will be somewhat the same as with a good LTE aggregation solution, but monetisation options are unlimited here due to robust train-to-track channel speed and low latency.

Using existing elements can help to decrease costs of TSN dramatically: with ballpark $50K per km of track (not tunnel!), up to $15K can be saved by using existing fiber and power infrastructure.

You can easily estimate LTE prices that are displaced with own TSN by multiplying average data package price, amount of sim cards per router, amount of head cars and the intended period of operation.

60Ghz TSN

It is still a theoretical since there are no known productive deployments but using higher millimeter bands allow to utilize hundreds of megahertz of spectrum leading to 1Gbps+ throughput.

Pros:

The highest possible throughput
Relatively cheap equipment
Compact embedded form-factor with no antenna feeders
Usually unregulated spectrum

Cons:

Twice more base stations
Installing equipment outside the train might be required, but is impossible on railways in some countries, including EU.

Summary to TSN

If the potential license is limited to passenger Wi-Fi, it is subsidized and speeds more than 50Mbps per train are not expected, we TSN. If the investor can employ additional monetisation models, including services for MNOs and transport operators, TSN is worth detailed exploration even if its deployment seems hard in given environment.

Satellite

Satellite routers are historically used for environments with no cellular coverage and no possibility of installing a TSN. These include aircrafts, marine liners, railways in the largest countries with low population density. In short, costs, especially OPEX,

are really high, and we’d recommend to consider this technology outside aircrafts only in combination with some others (LTE aggregation, TSN in more populated areas) and at scale (when you can buy out a substantial wholesale bandwidth from the satellite operator).