18-11-2015 | | By Pelle Svensson
The Internet of Things (IoT) and the volume of data that it brings is going to impact almost every industry. Current predictions suggest 25 billion IoT devices will be in place by 2020.
Clearly getting the design of an IoT solution right from the beginning is critical but using a single term to describe these 25 billion connected devices can be misleading, as the only thing these devices have in common is that they are all connected and even the wireless standard used for the connection will vary between and within systems.
Each connectivity function will require a trade-off between such factors as range, bandwidth, power consumption and security, and this will naturally lead to multiple wireless standards being deployed in many systems. And while multiple standalone connection devices can be implemented to deliver this functionality, these will increase size, cost and, because additional regulatory testing and reporting will be required, time to market.
To counter this, IC vendors are starting to produce multiradio solutions, which typically include at least Bluetooth, Bluetooth low energy and Wi-Fi. Here are three situations in which multiradio devices could prove essential when creating IoT systems.
Creating wireless gateways for communication with multiple up/downstream devices
Wireless gateways route packets from a wireless device to the network, bringing together the functions of a wireless access point, router and firewall and often acting as protocol converter, taking data from several downstream devices and transferring this converted data in the required format (eg RESTFul, XMPP or MQTT) upstream.
A good example of this is a home automation system where battery powered individual devices connect to the gateway via a low-power, low-bandwidth connection such as Bluetooth low energy. The gateway uses Wi-Fi to transmit the combined information to a control system or tablet. A second example could be a medical infusion pump with handheld scanners to confirm the patient or the correct medication is being administered and a Wi-Fi link to provide a higher bandwidth to communicate with the hospital network.
Multiradio solutions are particularly suited to such systems and where there is a need for different wireless technologies to connect devices in a gateway configuration.
Discovery / proximity detection and transfer between two devices
Wireless devices often need to connect automatically when they come into range of one another. This typically requires a tradeoff with the discovery requiring a low-power standard, such as Bluetooth low energy, and the subsequent data transfer requiring a higher bandwidth.
A good example of this is a hand-held payment terminal for retail systems, with the Bluetooth low energy identifying the nearest receipt printer to the terminal before handing over to classic Bluetooth (or Wi-Fi) to handle the data transfer.
Managing coexistence and its interference
Coexistence is typically seen as a problem between devices. Indeed, the FCC also requires receivers that operate within the ISM (industrial, scientific, medical) band tolerate interference of other transmitters within the same band. But, even where devices run in (semi) isolation it’s not uncommon for individual systems to require wireless technologies to run concurrently. And while the side effects from signal interference (simultaneous data transmission / reception and data loss) can be negated through packet traffic arbitration this still results in latency.
It is important to control this in mission-critical industrial and medical applications, but the problem affects virtually all multi-standard wireless devices, from the phone on down and balancing this problem will be essential when it comes to IoT applications.
Using a standalone multiradio device means coexistence is handled within the multiradio chip, shrinking development times, cost and time to market vs multiple single-technology radios.