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In recent months, IEEE Standards Association has published Wi-Fi
standards IEEE 802.11-2016 and IEEE 802.11ai-2016, and are available for
purchase in the IEEE Standards Store and IEEE Xplore®.
As reported in the September 2016 issue of IEEE VT Magazine [1],
IEEE 802.11-2016 and IEEE 802.11ai-2016 were developed by IEEE 802.11
Task Group mc and IEEE 802.11 Task Group ai, respectively. IEEE
802.11-2016 is an update to the IEEE 802.11-2012 standards, with the
inclusion of the following 5 amendments published in 2012 and 2013:
- IEEE Std 802.11aa™-2012: MAC Enhancements for Robust Audio Video Streaming
- IEEE Std 802.11ac™-2013: Enhancements for Very High Throughput for Operation in Bands below 6 GHz
- IEEE Std 802.11ad™-2012: Enhancements for Very High Throughput in the 60 GHz Band
- IEEE Std 802.11ae™-2012: Prioritization of Management Frames
- IEEE Std 802.11af™-2013: Television White Spaces (TVWS) Operation
In addition, IEEE 802.11-2016 offers an enhanced timing measurement protocol, named the Fine Timing Measurement (FTM) protocol, to support indoor ranging and position. The FTM protocol has been adopted by the recently launched Wi-Fi Alliance CERTIFIED Location program, whose aim is to enhance Wi-Fi indoor positioning capabilities [2].
IEEE 802.11ai-2016 defines mechanisms that provide IEEE 802.11 networks with fast initial link setup (FILS) methods that do not degrade the security currently offered by Robust Security Network Association (RSNA), already defined in IEEE 802.11. Technical highlights of this project include FILS capability indication, and the optimizations of:
- AP and network discovery
- Security setup
- IP address assignment
In [1] and [3], the latest progress in the development of some projects, including IEEE 802.11ax and IEEE 802.11ay.bb, were included. Since September 2016, both projects have seen significant advances.
For IEEE 802.11ax, an IEEE 802.11 Working Group letter ballot on draft 1.0 was conducted from 1 December 2016 to 8 January 2017. However, the letter ballot was  failed because the result did not meet the requirement of more than 75% approval ratio.
Over 7300 technical and editoral comments were received from this letter ballot and the Task Group ax is now making headway in resolving these comments.It is expected that all of the comments will be resolved by September 2017 and an IEEE 802.11 Working Group recirculation ballot on draft 2.0 will be conducted afterwards.
In [3], it was reported that the task group discussed a number of technical proposals including OFDMA, uplink MU-MIMO and 1024 QAM. Since publication, the task group has agreed on the following technology building blocks for IEEE 802.11ax:
- OFDMA for both downlink and uplink with 20 MHz, 40 MHz and 80 MHz tone plans
- Uplink MU-MIMO that is capable of serving up to 8 simultaneous users
- Two additional modulation and coding (MCS) formats (MCS 10 and MCS 11) that utilize 1024 QAM, the use of an 256 FFT, rather than an 64 FFT, in 20 MHz channel for the data portion of IEEE 802.11ax PDDU that helps improve efficiency and data rates
- Introduction of spatial reuse
- Improved resource scheduling mechanisms, in which acknowledgments from different stations to their associated access point are transmitted using trigger-based PPDU format while an access point can initiate uplink transmission by means of a trigger frame and the corresponding stations respond with a triggered-based PPDU SIFS time units after the reception of the trigger frame
For IEEE 802.11ay, an IEEE 802.11 Working Group comment collection on draft 0.3 was conducted from 21 March 2017 to 30 April 2017. It is expected that an IEEE 802.11 Working Group letter ballot on draft 1.0 will be conducted in July this year.
In order to support a maximum throughput of at least 20 Gbps measured at the MAC data service access point, and support indoor and outdoor operations in licensed-exempt bands above 45 GHz, IEEE 802.11ay considers MIMO technologies, channel bonding of two or three 2.16 GHz channels (which results in a contiguous 4.32 GHz and 6.48 GHz channel) and channel aggregation of non-contiguous channels.
In particular, both single-user MIMO and downlink MU-MIMO are proposed for maximizing throughput and allows the distribution of capacity to multiple non-AP/non-PCP stations, respectively. Furthermore, antenna polarization (including vertical and horizontal polarization) and hybrid precoding (defined as a combination of analog beamforming and digital baseband precoding) are being considered.
References
[1] E. Au, "The latest progress on IEEE 802.11mc and IEEE 802.11ai," IEEE Vehicular Technology Magazine, Vol. 11, No. 3, pp. 19–21, September 2016.
[2] http://www.wi-fi.org/news-events/newsroom/wi-fi-certified-location-brings-wi-fi-indoor-positioning-capabilities
[3] E. Au, "Exciting projects for PHY and MAC layers of IEEE 802.11," IEEE Vehicular Technology Magazine, vol. 11, no. 2, pp. 79-81, June 2016.
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