4 ways to make indoor positioning work

VLC, Bluetooth, WiFi, or LiFi: which technology wins?

Indoor GPS is changing the way we move through our built environment. It's already inspiring a new generation of architects, designers, retail strategists, and ergonomic experts, among others, to rethink the spaces where we live and work. But ensuring that new indoor location-based services function optimally means making some important technology choices. What's the best way to implement them?

Here's what you need to know about the leading candidates in this exciting, fast-changing realm.

Visible light communication (VLC)

Instead of relying on invisible radio waves, like a wireless network does, VLC uses fluctuations in light imperceptible to the human eye to exchange arbitrary data with nearby sensors, allowing it to pinpoint a user's or an object's location on a map of an indoor space. Typical VLC receivers include smartphone cameras, mobile computers, and IoT devices equipped with light sensors. A common use case would be to use a smartphone for indoor navigation. A user directs a device’s front-facing camera at the ceiling, from which the lighting system is beaming out its signals.

Strengths:

VLC is the most accurate indoor positioning solution, achieving location resolution down to 30 cm or even less.
VLC is already possible using many connected lighting solutions available today; your building's luminaires may already be VLC-ready.
Most commodity-grade smartphone cameras can read VLC data, meaning visitors don't need new hardware.
VLC offers fast location fixes and position updates. It can define a location within 0.1 seconds and update it every 0.2 seconds.

Weaknesses:

VLC requires clear line-of-sight between luminaires and sensors.
VLC does not function when lights are off or very dim.

Bluetooth

Bluetooth emerged as a personal area network technology to make it easier to wirelessly connect related devices, such as a keyboard and computer or a smartphone and headset. It's extremely common in wearables and personal smart technology, and it's frequently found in IoT devices as well.

Strengths:

Bluetooth hardware is relatively inexpensive, so it can be added to network infrastructure at acceptable costs.
Most portable smart devices are Bluetooth compatible.
Bluetooth does not require line-of-sight.
Although signal strength will be diminished, Bluetooth can penetrate clothing and some personal items.

Weaknesses:

Bluetooth must pair with WiFi to achieve data transfer rates that can handle large amounts of data
Common Bluetooth positioning systems are accurate only to about 2 to 3 meters.
Using Bluetooth for indoor positioning requires the deployments of many beacons--up to hundreds depending on venue size. These are often battery powered, which represents installation and maintenance burden

WiFi

WiFi is the brand name for the related family of wireless networking standards that hit the market in the year 2000.

Strengths:

WiFi is so successful and pervasive that it's virtually universal. That means that almost every building already has a WiFi networking infrastructure in place, and that almost every visitor to it carries at least one WiFi enabled device.
WiFi does not require line-of-sight, and can penetrate clothing and small personal items like briefcases, backpacks, and purses.
Modern WiFi networks are extremely high bandwidth, rivaling wired networks in some cases.
Simply measuring the signal strength between a device and available WiFi access points provides rough position data, meaning you can start developing indoor location services with no additional hardware and minimal software effort.

Weaknesses:

Although WiFi systems specifically designed for indoor location using antenna arrays can be accurate down to a couple dozen centimeters, common WiFi implementations offer the lowest accuracy of major indoor positioning solutions: to five meters at the most.
WiFi is designed for reliability but is subject to interference and latency that can slow performance.
WiFi radios are more power-hungry than some other wireless solutions, particularly Bluetooth Low Energy.

Combined solutions, and the LiFi future

A hybrid model that incorporates the best elements of multiple technologies will likely emerge as the surest way to deliver robust location services. The best combination will depend on the particulars of your space and the demands of your location-based services.

Pairing VLC and Bluetooth is a strong play for many applications. VLC's superior accuracy lets you tailor your services and messages to a very specific point, with little risk of mistakes. Bluetooth provides the return channel via which the user's smart device can communicate back to your location services for more information. Bluetooth also provides backup location that, while less accurate than VLC, can be used in adverse lighting or when the visitor has all of his or her devices securely tucked away.

On the other hand, WiFi's longer reach and greater capacity may be more appropriate for high-traffic settings like airports, sports arenas, and convention centers, where greater bandwidth and more reliable connections are important. Precise VLC data can then correct the coarser location data when the user engages with an app.

None of that, of course, is to mention the potential next kid on the block in terms of indoor location innovation: LiFi (light fidelity). LiFi is essentially VLC on steroids: a technology for enabling high-bandwidth communications through LED light without using any radio waves at all. LiFi is in its early days yet, and devices don't yet incorporate LiFi receivers. But they soon will, and LiFi promises to support the 5G roll-out that's coming in a couple of years.

Whatever the solution proves to be, your vision, as well as growing interest and demand from users, will guide the evolution and determine the success of your location services. In terms of implementation, though, a combined solution will almost certainly prove to be closest to ideal.