Wifi Halow radio demonstrated at DAC
June 9, 2016
At this week’s Design Automation Conference in Texas, nanoelectronics research centre Imec, Holst Centre and wifi IP provider Methods2Bussiness are presenting a complete wifi Halow radio for IoT applications.
The low-power, long-range radio uses a claimed ten times less power than state-of-the-art orthogonal frequency division multiplexing (OFDM) radios. It can be used for a broad range of applications related to the IoT and complies with the recent wireless networking protocol, IEEE 802.11ah.
The radio’s compliance with the recently amended wireless networking protocol ensures that it is 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 with other IoT standards, its sub-GHz carrier frequency and mandatory modes with 1 or 2MHz channel bandwidths allow devices to operate over a longer range with scalable data rates from 150kbit/s to 7.8Mbit/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 Belgium-based Imec and Holst Centre’s sub-1GHz IEEE 802.11ah transceiver and Dutch company Methods2Business’ medium access controller (MAC) hardware and software IP and application layer to enable 802.11ah communications 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 optimised 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 down to 7.1mW in transmit mode for 0dBm output power.
The 802.11ah MAC core implements all the new wifi Halow functionality to address the drawbacks of traditional wifi in the IoT. Besides mandatory features for connecting up to 8000 IoT clients (hierarchical AID), improving collision avoidance in channel access mechanisms (CSMA/CA, DCF, EDCA), and increasing throughput by supporting shorter MAC headers, advanced power saving modes such as target wake time (TWT) and restricted access window (RAW) are also supported. To trade-off power versus performance, time-critical functions are implemented in hardware while higher level MAC protocols are realised in software.
Imec’s connectivity research for the intuitive IoT focuses on the development of small, low-cost, intelligent and low-power sensors, radio chips and heterogeneous sensor networks. The 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 as humans need or want them to, providing assistance in an unobtrusive way.