Showing posts with label [Atheros]. Show all posts
Showing posts with label [Atheros]. Show all posts

Saturday, March 7, 2015

Qualcomm on 802.11ai

Ref: https://www.qualcomm.com/invention/research/projects/wi-fi-evolution/80211ai

Improving the Wi-Fi user experience.

Qualcomm is leading the way in developing IEEE802.11ai based technologies that significantly improve Wi-Fi user experience as well as address many Wi-Fi deployment pain points for operators.


Operators are increasingly relying on Wi-Fi to enable Cellular offload and offer Wi-Fi-as-a-Service. However, users often turn off Wi-Fi when they encounter an unsatisfying experience such as poor connectivity, long connection times, poor roaming experience, reduced bandwidth due to spectral inefficiency (excessive management frames), etc. Qualcomm Research has developed 802.11ai based technology to solve such issues which are pervasive in today’s public Wi-Fi networks.

Benefits of 802.11ai

·         Fast Initial Link Setup (FILS): Legacy Wi-Fi link setup in operator managed networks may require exchange of up to 27 messages between the STA, AP and Authentication Server. 802.11ai based FILS reduces the number of link-setup messages to 4, significantly improving link-setup speed and robustness, while also reducing signaling overhead. By using FILS, the initial link set-up time can be improved ~15x.

·         Fast Wi-Fi Roaming: Good user experience in operator managed Public and Community Wi-Fi networks requires fast and seamless roaming of STAs across APs with different SSIDs and Subnets. Legacy Wi-Fi link setup and roaming procedures either completely stall or cause a 9-10 second outage when roaming across different SSIDs and/or Subnets, thereby inhibiting seamless user experience and making it unsuitable for real-time voice and video applications. 802.11ai enables fast Wi-Fi roaming by assisting STAs to quickly choose and connect to the right AP, bringing the interruption down to less than ½ a second.

·         Increased Capacity: For users already connected to a Wi-Fi AP, the arrival of a large number of new users can cause what is known as “probe storms” and/or “association storms” and consequently lead to a temporary service outage. This is a common problem in busy train or subway stations and airports. Also, operators of dense Wi-Fi networks observe decreased capacity as 20-60% of the medium is occupied by management frames overhead.
802.11ai FILS and probe storm reduction techniques can significantly reduce the medium overhead attributable to probe requests/responses, beacons and link setup signaling, resulting in increased capacity and better user experience even as hundreds of new users try to access the Wi-Fi network.

·         Additional Operator Benefits: 802.11ai enables a flexible Wi-Fi deployment model for operators, with no need for a central AP controller. APs from multiple OEMs can be easily deployed and the network can be configured with different SSIDs and subnets while maintaining good user experience and roaming performance. Additionally, 802.11ai authentication methods are designed to eliminate interaction with and reduce load on operator HLR/HSS.



Related Videos

 https://www.qualcomm.com/videos/wi-fi-advanced-airbrush-overview

Qualcomm on 802.11ah

Ref: https://www.qualcomm.com/invention/research/projects/wi-fi-evolution/80211ah

Improving whole home coverage and power efficiency.

Illustration of 802.11ah
IEEE 802.11ah is a new PHY and MAC design that operates in the sub-one-gigahertz (900MHz) band. 11ah is intended to support extended range Wi-Fi, and the Internet-of-everything (IoE). The 11ah PHY and MAC are optimized from the ground up for extended range, power efficiency, and scalable operation. The new 11ah design enhances link-budget compared to 2.4GHz technologies. 11ah supports mandatory and globally interoperable 1 and 2 MHz bandwidth modes which open up new use cases for Wi-Fi: IoE, home automation, smart grid, wearable consumer electronics, low-power sensors, etc. 11ah also supports 4, 8, and 16 MHz bandwidths for higher-data rate applications (e.g. in the US where 26MHz is available in 900 MHz band). 11ah extends the range of Wi-Fi beyond the limited range of 2.4 and 5 GHz by leveraging the improved propagation and penetration of 900MHz radio waves through walls and obstructions. With 11ah, Wi-Fi coverage improves in previously hard to reach places such as garages, back yards, attics, buildings, factories, malls, etc.
A single 11ah AP can provide whole home coverage. It can also support low cost battery powered sensors operating without a power amplifier and which use interoperable 1&2 MHz bandwidth modes. A 150 Kbps minimum data rate results in short on-time for sensors with short bursty data packets thus lowering their power consumption. Overall power is also reduced by using lower power MAC protocols such as smaller frame formats, sensor traffic priority, and beaconless paging mode. 11ah MAC is also optimized to scale to thousands of nodes by using efficient paging and scheduled transmissions. 11ah leverages the Wi-Fi ecosystem & IP network for easy setup & pairing to AP/mobiles. 11ah devices are interoperable across vendors.
11ah is being standardized in IEEE with a draft 2.0 version expected in mid-2014. Our Wi-Fi Advanced, along with other participants, have been leading these standardization efforts.


Qualcomm on 802.11ac

Ref: https://www.qualcomm.com/invention/research/projects/wi-fi-evolution/80211ac

Pushing capacity and performance improvements.


Illustration of 802.11ac

IEEE 802.11ac is the next evolution of Wi-Fi—to push capacity into Gigabits-per-second in order to meet the 1000x challenge. 11ac mandates operation in the 5 GHz band where there is relatively less interference and more channels are available, compared to the 2.4 GHz band used by previous 11 a/b/g/n standards. 11ac uses wider bandwidth and up to eight spatial streams to achieve a maximum of 6.93 Gigabits-per-second theoretical throughput. 11ac also enables new use cases such as multiple HD video streams throughout the home by improving spectral efficiency.
With an ever-increasing number of Wi-Fi-enabled devices present in enterprise and home (i.e., higher attach rates) 11ac is the ideal evolution in the Wi-Fi standard, using advanced techniques that leverage spectral efficiency and higher bandwidth, ultimately providing needed capacity and performance gains. Qualcomm VIVE includes an entire ecosystem of 11ac solutions that will accelerate the transition to next-generation of Wi-Fi.
11ac is fully backward compatible with 802.11n. It operates in the 5 GHz band and uses up to 160 MHz bandwidth. In addition, it uses spatial division multiple access (SDMA) techniques to enable multi-user MIMO or MU-MIMO. Operating in 5 GHz band reduces interference and antenna size requirement, allowing for smaller antenna sizes for portable devices, leveraging wider bandwidths (20, 40, 80, and optional 160 MHz) and increases in data rates.
We have demonstrated MU-MIMO PHY operation running on a prototype 11n module with a MU-MIMO software overlay. Results showed a 3x improvement in PHY rates compared to 11n. This is shown in this video (link).
All of the above features have been standardized in IEEE under 11ac which are explained in this white paper (link). Qualcomm Research, along with other participants, lead the standardization efforts for these features.
Related Videos

Related Documents
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