Until recently, in any specific application, only one wireless technology was generally used for end-to-end wireless transmission. However, that model has changed with the evolution of the Internet of Things (IoT). Take the example of a medical infusion pump. Bluetooth low energy might be used with a handheld scanner to ensure that the pump is being connected to the right patient and that the correct medication is being administered, but within the same pump a Wi-Fi link might be used to send continuous monitoring data over a hospital network.
The IoT is inherently scalable: a network of embedded devices that collect and exchange data over any distance using a range of communications technologies, wired and wireless. With a plethora of radio protocols now available, each suited to specific applications, it makes sense to integrate multiple types in an embedded design. For instance, there is often a requirement for two wireless-enabled devices to connect automatically when they come within range of each other; one radio technology being used for device service discovery and another for data exchange.
The new paradigm
Demand for multiradio devices has led to the development of multiradio modules that typically include Classic Bluetooth, Bluetooth low energy and Wi-Fi in a single package. Compared to multiple discrete radios, multiradio devices can reduce size, design effort and cost (both implementation cost and cost of final product).
While minimal size and cost are prime concerns for smartphone manufacturers, other sectors experience the same constraints. To fulfil their goals of being multi-tasking units, handsets typically integrate a host of wireless protocols in addition to cellular –Classic Bluetooth, Bluetooth low energy, Wi-Fi (2.4 GHz and 5 GHz), FM radio, satellite navigation and NFC. A single multiradio solution can dramatically reduce the wireless implementation size and cost, whilst using a pre-certified module can reduce the headache of securing type approval from the various radio regulatory authorities to almost zero too.
A distinct advantage of a multiradio is that there are fewer external components as they are likely to integrate low-noise amplifiers, antenna matching components, oscillators, crystals etc. that would otherwise be external to the radio device. In contrast, a ‘DIY’ RF implementation using multiple discrete radios typically means more components, more circuit board real estate and more testing. The reduced design effort and risk is a considerable plus point for any product where speed to market is an issue.
Tried and tested
In this vein, it’s worth mentioning that with any system requiring wireless technologies to operate concurrently, there’s potential for signal interference that results in higher latency because of the need to use packet traffic arbitration to avoid simultaneous data transmission and reception, or even data loss due from receiver input saturation. Optimising coexistence of the various wireless technologies to ensure interference-free operation isn’t for the faint-hearted or time-short! In a stand-alone multiradio device, wireless coexistence is handled within the multiradio chip as a matter of course.
A final point to consider is the flexibility that multiradio modules offer. Multiradio solutions are an ideal choice when different wireless technologies are needed for a gateway configuration i.e. one technology communicates downstream to sensors and actuators, whilst a second radio communicates with networks upstream. Equally, a single physical implementation can be employed across a series of products, even when different products will use only one of the available wireless protocols. So whether your product employs one protocol or several, a multiradio module could be just the thing to avoid your design team going ‘radio gaga’!