Imagination is moving away from software defined radio and back to a more traditional approach with its Whisper radio processor unit.
Imagination sees a clear demand for Bluetooth and WiFi, and is already positioning itself for the coming sub-GHz, lower data rate 802.11ah WiFi standard that will be a contender for IoT nodes. It can also handle other 2.4 GHz protocols, although Imagination has put less focus on this. Edgar confirms the architecture will support both popular 802.15.4 implementations, Zigbee and 6loPAN, which itself forms the basis of the recently announced Thread protocol used by Nest.
But Edgar does acknowledge that the majority of the power consumption of such nodes is in the RF front end rather than in the digital processing, so there are a range of techniques in the digital baseband to minimize the need for external elements that increase the power, such as how to control the power amplifier. Some of this does include digital pre-distortion, which modifies the transmission to match the linearity of the PA and so avoid wasted output power. This tends to be used in higher power applications at 10-15dB rather than the lower power of 0-5dB that is more likely for lower cost IoT nodes.
Many devices claiming to address IoT today are in fact repurposed from other markets such as mobile or embedded, says Tony King-Smith, EVP marketing at Imagination. Hence this configurable approach to deliver exactly what is required for the target applications of IoT, wearables and eHealth, but no more.
Imagination will start to roll out a line of Ensigma "Whisper" cores in the fourth quarter of 2014 with particular, as yet unannounced, combinations of Warrior core, modem and PHY interfaces. This marks a significant step away from its championing of SDR architectures in pursuit of the higher volume IoT and wearable markets.
— Nick Flaherty is a technology writer for EE Times Europe and EE Times.