With the devices, sensors and broadcast beacons that comprise the Internet of Things (IoT) set to explode with the rollout of 5th-generation mobile communications, the keepers of a long-time connectivity standard are using trajectory to gain a measure of that growth – right down to the centimeter.
Unveiled last week as part of the latest low-power version of its 21-year-old source code, the Bluetooth Special Interest GroupOpens a new window (SIG) helps developers calculate both the position and direction of instruments embedded within the tech as they move.
Likened to global positioning systems used in satellite communications, the new functionality will boost IoT uptake in warehouse, factory and institutional settings. It will also become commonplace in homes as Bluetooth connectivity facilitates communication among the fast-growing number of smart devices.
Bluetooth Beds Down
Bluetooth Low Energy (BLE) underpins a frequency-hopping spread spectrum that permits devices and sensors to transmit data over 40 channels in the 2.4 GHz band. Also known as the ISM band, the unlicensed frequency is used for radio communication in industrial, scientific and medical applications.
BLE lets devices share information point-to-point for uses such as passing songs from a media player to a wireless speaker system. It also can be used to create large-scale networks in which connected devices form a mesh to relay information and execute commands.
With 5G rollouts already underway in a dozen US cities, the SIG expects the number of devices carrying embedded Bluetooth connectivity to increase to 400 million by 2022. Using multiple receivers in a field array to gather transmission data lets Bluetooth developers utilize the dubbed “location services†to track those instruments with greater precision, according to the SIG.
Last year, a Belgian research institute reduced the accuracy of proximity calculations from three meters to 30 centimeters for a standard Bluetooth signalOpens a new window . The SIG claims the new functionality betters that performance, taking it down to a single centimeter.
The SIG says that delivery of location services relies on proximity sensing, and enabling devices to tell each other where they are in space in order to send alerts based on that information. So-called electronic leash applications calibrate distances based on signal strength, but at fairly arbitrary rates that often limit their effectiveness in device tracking.
Radar That Can Turn Corners
Borrowing from techniques used in aviation, the Bluetooth 5.1 spec can calculate approach and departure vectors to let users know in what direction and how fast objects are moving. The calculations include any transmission in the mesh of multiple relays that the fifth version of the software, introduced at the end of 2016Opens a new window , was designed to facilitate.
In angle-of-approach deployments, tags transmit signals through a single antenna to multiple receivers and calculate direction based on reception times. Angle-of-departure arrays reverse those configurations, using multiple transmitting beacons and a single antenna, most commonly on a mobile device.
Indoor positioning is increasingly common in institutional settings like airports and hospitals, where directional beacons can help visitors get from point to point. Using the range-finding technology, tbe SIG maintains that fewer signaling beacons are required for wayfinding than in current deployments. Those deployments also will get a boost from more precise signaling: In museums, for example, users could obtain information on objects they view.
The self-styled Point-of-Interest information solutions also find applications in retail environments. Bluetooth increased the amount of data contained in a transmission packet by more than eightfold in the 5.0 release.
Tracking IoT items with Bluetooth beacons will get easier, too, as precision tracking lets users follow sensor-equipped tools, parts and products in factory and warehouse settings, sparing time and improving safety.
Medical applications include blood-pressure monitoring and automated blood glucose level checks. Those features are also at work in a variety of body composition sensors used to measure heart rate, speed, power and exercise cadence.
Low-energy applications in the ISM band also include environmental, usage and connectivity sensors, including for wireless devices such as computer keyboards and point-and-click devices. The typical distances between hardware in those applications are less than 330 feet.
A Real-Time Locating System (RTLS) can find people and things equipped with Bluetooth sensors and track them in physical space. They use locator beacons that connect to a centralized location engine, usually housed in a server, which calculates proximity from signal strength.
Using the same principal, the increased spectrum of frequencies permitted by 5G can be harnessed in directional beamsOpens a new window for pinpoint delivery, including around corners in urban settings. Indoor positioning systems use beacons to deliver messages to user devices, among them directions for negotiating labyrinthine buildings.
Utopia for the Forgetful
The SIG, which lists US companies IBM, Intel and Microsoft among its members, has taken aim at IoT applications since releasing BLE almost a decade ago, Since then, developers have built on the advances in distance and signal strength to incorporate the direction-finding capability.
Bluetooth 5.0’s increased range of 800 meters for transmission signals marks a four-fold increase, and has both industrial applications and remote control capabilities for in-home climate and lighting. Bluetooth also doubled the transmission speed of BLE to 2mbps, permitting IoT sensors and devices using the tech to better stream audio, video and images in higher-volume data packets.
Coupled with the forward error correction (FEC) recovery, BLE transceivers can resume transmission at the point of signal breaks instead of starting the process over again when connectivity is restored. With its new direction-finding functionality, FEC lets BLE-equipped instruments overcome the noise and impediments associated with physical barriers to signals in crowded environments.
The SIG says RTLS will help in retrieving misplaced items like car keys and wallets. Fobs and devices equipped with direction-finding capability makes it possible to see whether personal items are on the move, saving steps, time…and headaches.