Two alternate physical layers (PHYs), TASK and RS-GFSK, are specified in this amendment in addition to the PHYs of IEEE Std 802.15.4-2015. The amendment also defines the medium access control (MAC) modifications needed to support the implementation of the TASK and RS-GFSK PHYs. These alternate PHYs enable low-cost, ultra-low power consumption, as well as extended battery life, in various frequency bands and geographical regions under multiple regulatory domains.

This amendment defines an ultra low power (ULP) physical layer operating in sub 1 GHz and 2.4 GHz license exempt bands supporting typical data rates up to 1 Mbps. This amendment also defines the necessary MAC changes required for supporting the new ULP physical layer. The desired peak power consumption for the PHY should be typically less than 15 mW.