Apple's announcement of extended support for its iBeacon platform in the latest version of iOS has made beacons a hot topic. The technology is set to drive a new level of proximity-based services in smartphones and other mobile devices. But what exactly is a beacon? Let's take a closer look at the technology and its applications.
A beacon is essentially a low-cost Bluetooth Smart wireless transmitter, designed for indoor use, which is placed in a particular location or point of interest. The beacon transmits its identity to any Bluetooth Smart Ready devices within range; those hosting a companion app can be located, and the software can trigger various types of notifications. It could be that suitable information about that point of interest is displayed, or devices may allow audible alerts or vibrations.
Because beacons have the potential to locate smartphones indoors to within a few meters, they could potentially provide a kind of indoor GPS, but crucially, they could also allow content specifically targeted to that location to be delivered to users who want it.
The development of Bluetooth v4.0, the technology behind Bluetooth Smart (which uses technology that adheres to the Bluetooth specification's Low Energy Core Configuration and was previously called Bluetooth low energy) and Bluetooth Smart Ready, has made the whole beacon idea feasible; devices with the right hardware can now communicate over reasonable distances using only a very small amount of power, essential for battery life in today's mobile devices.
Beacons themselves, depending on the exact implementation of the hardware, can achieve up to two years of battery life from a single coin cell, despite a range of more than 50 meters. In fact, Bluetooth Smart uses such a small amount of energy, it lends itself to technologies like energy harvesting that do away with the battery altogether. This can only help the adoption of beacons, since never having to replace the battery can reduce maintenance requirements.
Promoted by Apple
While the idea of using Bluetooth Smart beacons for indoor micro-location has been around for a while, a recent move of support from Apple means it looks set to enter the mainstream. Apple's iBeacon platform launched in 2013, but, with the 7.1 version of iOS, Apple gave the technology another boost. With the new operating system, devices were set to automatically listen for beacons, even without a beacon app running on the smartphone. This functionality also makes it harder to switch off notifications once the app is installed.
Although Apple is pushing its iBeacon platform for its Bluetooth Smart Ready iPhones, iPads, and iPods, the technology is actually platform-independent — any Bluetooth Smart beacon can communicate with Apple's devices, since Bluetooth wireless technology is inherently interoperable. This means any manufacturer's beacon can communicate with Android devices and other smartphones that are equipped with Bluetooth Smart Ready capability, too.
Beacon technology has been compared to other location-based technologies such as Near Field Communication (NFC), especially since Apple's version of NFC, AirDrop, uses Bluetooth technology to function. While NFC was designed for mobile payments, Apple uses its iBeacon technology for payments when users in the Apple Store check out with the company's app.
In practice, Bluetooth Smart and NFC are very different. NFC requires the sender and receiver to be very close together, usually within a centimeter, requiring the user to deliberately position the device next to the other terminal. In contrast, Bluetooth Smart does not require such close proximity, operating over a range in the order of tens of meters, so it can be used to communicate with smartphones that are still in the user's pocket. NFC also requires additional dedicated hardware in smartphones, whereas most have Bluetooth Smart Ready capability as standard.
Another factor driving beacon technology is that Bluetooth Smart ICs are widely available from many silicon vendors, and support infrastructure exists that can make beacon hardware and software development as straightforward as possible. For example, Nordic Semiconductor offers a beacon reference design, based on its nRF51822 System-on-Chip (SoC), which can be used to get iBeacon or proprietary beacon designs for iOS or Android smartphones up and running quickly (see Figure 1). The kit features companion smartphone apps for iOS 7 and Android 4.1/4.3 smartphones, plus Nordic firmware.
A sticking point for beacon design is typically the RSSI (received signal strength indication), which is used to estimate the distance between the beacon and the smartphone and is essential to determine the smartphone's location. The RSSI can differ between smartphone models because of the electromagnetic profiles of their enclosures. A beacon kit can have a tuning function included that allows consistent performance, regardless of which smartphone the beacon is communicating with.
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