Question: how ieee 802.15 is different from 802.11?
Answer: The legacy 802.15. 4 standard usually operates in the unlicensed 2.4 GHz band using Direct Sequence Spread Spectrum (DSSS), which can accommodate data rates up to 250 Kbps. On the other hand, the 802.11ah utilizes the sub-1 GHz license-exempt bands to provide an extended range to Wi-Fi networks.