Imec develop complete low-power WiFi HaLow radio solution

The radio solution’s compliance with the recently amended wireless networking protocol ensures that it is especially optimised for IoT-related applications. The WiFi Alliance recently introduced the HaLow designation for the new low-power, long-range WiFi protocol IEEE802.11ah. Compared to other IoT standards, its sub-GHz carrier frequency and mandatory modes with 1MHz/2MHz channel bandwidths allow devices to operate over a longer range with scalable data rates from 150kb/s to 7.8Mb/s. The standard uses OFDM to improve the link robustness against fading, which is important in urban environments, and to achieve a high spectral efficiency (data rate over a given bandwidth).

The radio integrates imec and Holst Centre’s sub-1GHz IEEE 802.11ah transceiver and Methods2Business’ Medium Access Controller (MAC) hardware and software IP and application layer to enable 802.11ah communication between large numbers of IoT clients and the internet using a central access point. The transceiver comprises a complete low-power physical layer implementation of RF front-end and digital baseband. It features a 1.3nJ/b fully digital polar transmitter optimized for IoT applications as well as for the novel IEEE 802.11ah WiFi protocol. The transmitter surpasses the tight spectral mask and error-vector-magnitude (EVM) requirements of conventional WiFi standards. It does so while demonstrating a power consumption rate as low as 7.1mW in Tx mode for 0dBm output power.

Methods2Business 802.11ah MAC core implements all the WiFi HaLow functionality to address the drawbacks of traditional Wi-Fi in IoT. Besides mandatory features for connecting up to 8.000 IoT clients (Hierarchical AID), improving collision avoidance in channel access mechanisms (CSMA/CA, DCF, EDCA), and increasing throughput by supporting shorter MAC headers, very advanced power saving modes like Target Wake Time (TWT) and Restricted Access Window (RAW) are also supported. To further trade-off power versus performance, time-critical functions are implemented in hardware while higher level MAC protocols are realized in software.

Imec’s connectivity research for the intuitive internet of things focuses on the development of ultra-small, low-cost, intelligent, and ultra–low power sensors, radio chips and heterogeneous sensor networks. Imec’s Intuitive IoT R&D programme focuses on developing the building blocks for future IoT-related applications, with intuitive technology where sensor systems are aware of humans, human perspectives, and human’s environment. This intuitive IoT technology can react exactly as humans need or want them to, providing assistance in an unobtrusive way. Interested companies are invited to join imec’s research efforts as research partners or they can have access to imec’s innovative technology through licensing programs for further development.