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IEEE 802.11ah: A Long Range 802.11 WLAN at Sub 1 GHz

80211ah802.11-1997 was the first wireless networking standard in the family, but 802.11b was the first widely accepted one, followed by 802.11a, 802.11g, 802.11n and 802.11ac. Other standards in the family are service amendments and extensions or corrections to the previous specifications.

  • 802.11b and 802.11g use the 2.4 GHz ISM band
  • 802.11a uses the 5 GHz U-NII band, which, for much of the world, offers at least 23 non-overlapping channels.
  • 802.11n is a wireless networking standard that uses multiple antennas to increase data rates. Its purpose is to improve network throughput over the two previous standards—802.11a and 802.11g
  • IEEE 802.11ac is a wireless networking standard in the 802.11 family providing high-throughput wireless local area networks (WLANs) on the 5 GHz band.

What is 802.11ah?

IEEE 802.11ah is a wireless networking protocol that is an amendment of the IEEE 802.11-2007 wireless networking standard. It aims to utilize sub 1 GHz license-exempt bands to provide extended range Wi-Fi networks, compared to conventional Wi-Fi networks operating in the 2.4 GHz and 5 GHz bands. It will also benefit from lower energy consumption, making it ideal for the concept of the “Internet of Things”.

The new standard is aimed at providing a long range Wi-Fi transmission. And, the prime use is intended to be in wireless sensor networking owing to power saving strategies. The devices operating in IEEE 802.11ah mode are believed to have long battery life and long network reach due to the propagation characteristics at below 1 GHz.

Possible Applications and Benefits:

802.11ah can be used for various purposes including large scale sensor networks, extended range hotspot, and outdoor Wi-Fi for cellular traffic offloading, whereas the available bandwidth is relatively narrow.

  • One of the goals of this standard is to ensure that the transmission ranges up to 1 km and that the data rates per user are above 100 kbit/s.
  •  IEEE 802.11ah standard will define operations below 1 GHz, it will not use the TV white space bands (54-698 MHz in the US).
  • Communication medium for the transmission of short-burst data messages from sensors, which include smart metering
  • can be used to create the backhaul of mesh networks created by IEEE 802.15.4 networks
  • Wireless communication in rural areas has led to some effort that is also titled as bridging the digital divide. Large potential is given by sub 1 GHz due to the wider supported range.

The standard is yet on the evolution process and is hoped to be completed by March 2016. 802.11ah is years out before we see any devices making use of this technology. But it would be interesting to keep an eye on it as the standard develops and how it will pan out in the Wi-Fi market. It is possible that in future we might see IEEE 802.11ah as a common network connectivity technology for large-scale networking.

References:

IEEE 802.11-11/1137r13, in: http://www.ieee802.org/11/Reports/tgah_update.htm