imec and Holst Centre presented the transmitter at this month’s IEEE International Solid-State Circuits Conference (ISSCC 2016). It is claimed to have a 10-fold power reduction, compared with OFDM transmitters.

At the Consumer Electronics Show (CES 2016) in January 2016, Compared to other IoT standards, its sub-GHz carrier frequency and mandatory modes with 1MHz/2MHz channel bandwidths allow devices to operate in a longer range with scalable data rates from 150kb/s to 2.1Mb/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 polar transmitter meets the tight spectral mask and error-vector-magnitude (EVM) requirements of conventional Wi-Fi standards, while the measured phase noise at 1.5MHz offset is -115dBc/Hz which is 15dB lower than the spectral mask requirement for the IEEE 802.11ah standard.

(The Wi-Fi Alliance introduced the HaLow designation for the new low power, long range Wi-Fi protocol IEEE802.11ah at CES (Consumer Electronics Show) in January. It is a protocol optimised for IoT applications.)

Both the far-out and close-in spectrum of the transmitter pass the mask with at least 4.8dB margin. The EVM is below 4.4%. The power consumption of the transmitter is as low as 7.1mW, when delivering 0dBm output power and operating from a 1V supply. This represents a 10-fold power reduction compared to OFDM transceivers, says the research centre, enabling the prototype transmitter chip to meet IoT application requirements.