Low energy, high impact
Francisco Aletta explores the infinite possibilities of BLE Urban Networks and explains the origins and goal of Tetramax: Technology Transfer via Multinational Application Experiments
Tetramax (www.tetramax.eu) is a EU-funded innovation hub for digitizing European industries in the domain of customised and low-energy computing (CLEC). Its mission is to boost innovation for SMEs in search of leading-edge digital technologies and solutions. In the framework of this programme, Etelätär Innovation (together with partners Intelligent Parking and Semab) is undertaking the BLEUN project (Bluetooth Low Energy Urban Networks), which aims to deploy accurate geolocation services for smart mobility applications and several other market segments in the Smart City.
ADVANTAGES OF BLUETOOTH LOW ENERGY NETWORKS RTLS
(Real Time Location Services) can be provided by using different existing systems, such as the GPS (global positioning system), RFID, UWB or Bluetooth.
GPS satellites continuously transmit data about their current time and position. A GPS receiver monitors multiple satellites and solves equations to determine the precise position of the receiver and its deviation from true time. At a minimum, four satellites must be in view of the receiver for it to determine its position.
GPS signals are relatively weak and can be easily blocked by mountains, trees, buildings, etc., thus the receiver device needs to allocate a certain amount of energy to the antenna to scan for these signals. A 2016 study by computer engineering professors in the UK and Saudi Arabia found that with a good signal strength, a battery depletes by 13 percent while a weak signal could cause the battery to drop up to 38 percent1 .
For this reason, GPS devices reach energy consumptions of 200 mAh in many cases, which would be equivalent to 1 watt/hour. In terms of CO2 , if we calculate 8,760W of yearly consumption for a device that is connected 24h/day, the CO2 generated would be 5,694g, following the formula published by the EU. In comparison, a BLE Beacon only needs 5µA, which translates in less than 1W per year, or 0.65g of CO2 .
Also, compared with RFID, due to the widespread adaptation of the Bluetooth standard, BLE solutions are cheaper and easier to integrate into other systems and everyday devices.
In fact, nearly all smartphones are already equipped with the technology. So BLE greatly simplifies every step of the process when smartphones and devices can be used as part of the real time location system.
We can find a similar situation with UWB (Ultra Wide Band). This system is very attractive due to the level of location precision afforded by ultra-wideband positioning systems. This precision is achieved thanks to the ability to accurately measure the time it takes for an encoded signal to travel from a transmitter to a receiver. However, this precision comes at an elevated cost, as much as 10 times more costly than a Bluetooth (BLE) system. Finally, UWB is not available in most smartphones currently in the market, making it unsuitable for any application requiring the use of these devices.
Though BLE can certainly not totally replace GPS, RFID or UWB in the market, as these systems have some very strong use cases, it clearly offers some net advantages for the needs of smart cities.
BUILDING BLE NETWORKS
There are two kinds of BLE devices: beacons and receivers. Both can be fixed or mobile. Mobile beacons are usually called “tags” or “trackers” and fixed receivers are often referred as “readers”, “nodes” when they are part of a network, or “gateways” when they also send the information to the Internet. Of course, there are many different models, sizes and specifications for each of these devices.
Smartphones can function both as beacons or receivers, thus, six different combinations of smartphones with fixed beacons, roaming beacons, receivers and software can be implemented to adapt to the environment and the purpose of the network.
Another remarkable characteristic of BLE devices is that they allow us to build networks using extended MESH topology, where each device (node) transmits its own data as well as serving as a relay for other nodes. This topology is based on non-hierarchical and dynamically self-organise and self-configure network and was originally developed for military communications, providing a robust and easily installed solution.
The redundant nature of mesh networks is an essential characteristic sought out, as in the event of a hardware failure, many routes are available to continue the network communication process. Therefore, high performance and scalable broadband networks can be built at very low cost using a mesh net. Autonomous roaming devices can join the network and exchange data with the nodes, extending this way the network coverage.
"BLE greatly simplifies every step of the process when smartphones and devices can be used as part of the real time location system"
BLE APPLICATIONS: THE BLEUN PROJECT
BLE networks can be used to develop a scalable system able to provide a great variety of functions and services at low cost. These services include outdoor location services, assets tracking, proximity marketing, POIs information and eventually indoor navigation.
- Proximity marketing: the customer (with a smartphone and specific app) gets some info, or an app is triggered when enters in the range of the beacon.
- Positioning/navigation: The beacon is fixed in a known position and sends a signal with a short information packet periodically (i.e. every 30 seconds) to identify itself. When a smartphone with a navigation app enters the beacon’s range, it can calculate the distance to the beacon based on the power of the signal received from it. If the smartphone is in the range of at least three beacons it can determine its position with a high level of accuracy.
- Tracking: The beacon is the roaming device and a series of receiver nodes detect the signal and send this information to gateways connected to the management centre to determine the position of the roaming beacon.
From here, possibilities are endless, for mobility, marketing, routing, navigation, and almost any application that we can imagine. Using this technology, the BLEUN project has allowed Etelätär Innovation to deploy the MOVERE solution (http:// etelatar.com/movere), an advanced system allowing the 360° operation of private e-bike systems. Targeted at business parks, intra-company networks, university campuses, hotel and golf resorts, marinas and eco-Tourism, MOVERE brings together:
- Last-generation e-bikes with 40-70+ km range per charge.
- Easily portable, closed modular stations (e-hubs) allowing e-bike storage and charging.
- Ready-made booking and management platform providing real-time information on available e-bikes and empty e-hubs.
- User-friendly mobile application stimulating usage, interaction and gamification (specially customised for corporations’ CSR strategies).
- Low-energy, IOT-based tracking for accurate pointto-point mobility.
 Tawalbeh, Mohammad & Eardley, Alan & Tawalbeh, Loai. (2016). Studying the Energy Consumption in Mobile Devices. Procedia Computer Science. 94. 183-189. 10.1016/j.procs.2016.08.028.