In an airport communications environment, LTE is a good choice for meeting the needs of a variety of stakeholders. Primary reasons to deploy an LTE network in such an environment are to:
- Unify disparate legacy radio networks
- Optimize the transit time of aircraft by unloading/loading data faster when on the runway
- Add more capacity to offer new services
- Improve passenger connectivity
Airports are one of the most complex technology environments on the planet. The design, airport layout, and security concerns -- combined with the pace of change from diverse requirements -- makes it an ongoing challenge to satisfy all stakeholders.
Network managers must provide infrastructure that will support new aircraft, new security demands, and passenger and automatic baggage handling services. The airport communications infrastructure needs to integrate building management systems, airlines networks, and data centers. It needs to support high volumes of traffic, including dedicated, priority communication services between aircraft and ground staff and between a range of authorities and enterprises servicing and operating in the airport.
Multiple technologies introduced over the last 10 years addressed these demands as they emerged. The technologies have multiplied and now include different PMR (e.g., Tetra), DECT, and Wi-Fi® standards. Multiple support contracts for these technologies are out of synch and some are approaching end-of-life.
The potential shift in contracts gives airports an opportunity to consider simpler contracts and alternative technology solutions. Some leading airports have already begun to seek an alternative wireless infrastructure.
For many providers, the answer is to move to a 3GPP standards-based LTE infrastructure. Features planned for introduction beginning in 2017 will make LTE a good fit for emergency services and other high-resiliency environments such as airports. LTE technology is more future-proof than other options, brings economies of scale, and will allow airport communications providers to offer more (and enhanced) services to companies that operate within the airport footprint.
In 2015, Bell Labs Consulting mobilized a team to work with 1 of the world’s leading providers of airport communications infrastructure. The team has also worked with a range of key airport stakeholders to determine the next wave of airport technology investments.
We have identified 10 key findings based on these engagements.
KEY FINDINGS FOR AIRPORT COMMUNICATIONS PROVIDERS
- No 1 size fits all. The optimal solution requires a combination of:
- Macro cells to cover outdoor areas (e.g., runways, roads)
- Outdoor small cells to provide extra capacity around the planes when at the terminal gates or at apron areas
- Indoor small cells to provide capacity in airport terminal passenger areas
- In-building DAS to supplement the coverage of small cells
- An FDD solution employing 20MHz of low band spectrum (e.g., 700, 850 MHz) with a shared carrier small cell configuration can:
- Support all the forecasted traffic from current airport professional customers such as airlines and flight catering companies
- Allow the introduction of new services
Permit the addition of new customers – including passengers and any airport businesses holding estate within the airport environment
While some airport authorities have considered allocating less spectrum, we’ve found that, for example, 10MHz may support the current airport personnel traffic, but not future or emerging needs. In such cases, new techniques that combine cellular with unlicensed bands such as LTE-U, Licensed Assisted Access (LAA), or LTE-Wi-Fi Link Aggregation (LWA) can be used to increase the system capacity when these are available.
Where the low-band spectrum is not available, 20 MHz of high-band TDD is a viable alternative.
A typical solution may use 10MHz for the macro cells and 10MHz for the small cells in a dedicated carrier configuration that allows the small cell ranges to be extended. In addition, the typical lower license cost of the high-band spectrum can compensate for the extra expense of having to deploy a larger number of macros to cover the same area.
- Because of redundancy requirements, the network needs to be over-dimensioned. However, this results in extra capacity that can be used to support new services and increase both market share and return on investment with the addition of new services (as noted in point 2 above).
- One key parameter that impacts profitability is the amount of existing DAS infrastructure that can be reused, since DAS capacity can be resold to other operators.
- Indoor airport design is mainly coverage-driven except for passenger areas. Small cells are needed to support expected future exponential growth of passenger capacity demands.
High level of macro interference for indoor environments in a small cell shared-carrier deployment does not greatly impact the overall cost of the solution, even though the small cell coverage is reduced.
This is because indoor airport areas constitute a complex mix of different spatial environments and only a few of these are greatly impacted by the macro interference. Many sections, such as deep indoor luggage sorting areas, are well isolated from the macro network.
Expected traffic in outdoor areas is more uplink-driven relative to traditional RAN deployments.
The downlink to uplink ratio is closer to 3:1 as compared to more traditional 6:1 to 10:1 ratios outside of an airport environment. This is due to real-time video calling from maintenance workers, which constitutes more than 80% of uplink traffic, and potential uploads of large amounts of data from airplanes to the control centers while at the gate or on runways.
- Outdoor areas of the airport such as runways need to be designed for high redundancy and reliability. This necessitates more macro cells compared to a traditional RAN deployment -- sometimes more than doubling the number of macros and outdoor small cells.
- Outdoor small cells are required to provide additional capacity and coverage in the areas outside the gates (apron and/or maintenance areas) where airport professionals work around the planes. The required number of outdoor small cells is more dependent on the physical area around the gate than on the capacity.
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