LB97 CID 170 20-40 Coex Date: 2007-05-14 Authors: May 2007 May 2007 doc.: IEEE 802.11-07/0707r0 May 2007 LB97 CID 170 20-40 Coex Date: 2007-05-14 Authors: Notice: This document has been prepared to assist IEEE 802.11. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802.11. Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures <http:// ieee802.org/guides/bylaws/sb-bylaws.pdf>, including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard." Early disclosure to the Working Group of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chair stuart@ok-brit.com as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE 802.11 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at <patcom@ieee.org>. John R. Barr, Motorola John R. Barr, Motorola

May 2007 doc.: IEEE 802.11-07/0707r0 May 2007 Abstract Summary of rational for not allowing use of 40 MHz channels in 2.4 GHz spectrum. John R. Barr, Motorola John R. Barr, Motorola

May 2007 CID 170 Comment: Allowing operation with 40 MHz channels in 2.4 GHz spectrum will not coexist with over 1 billion Bluetooth (IEEE 802.15.1a) devices present around the world. In addition, operation of 40 MHz channels in 2.4 GHz spectrum will be subject to high levels of interference from Bluetooth devices. With only 80 MHz allocated in 2.4 GHz spectrum allocation of half of that spectrum to a single WLAN limits access by other radios sharing that spectrum. Coexistence analysis shows a significant degradation of 802.11n performance in the presense of Bluetooth devices, even with significant separation. Many devices include both Bluetooth and 802.11 making inteference even more significant. AFH defined in IEEE 802.15.2 was designed to allow IEEE 802.15.1 devices to reasonably avoid 20 MHz wide 802.11 devices. None of the billion Bluetooth devices deployed at this time have been designed to avoid 40 MHz 802.11n devices. Proposed Change: Change “When using 40 MHz channels, it can operate in the channels defined in 20.3.14.1 (Channel allocation in the 2.4 GHz Band) and 20.3.14.2 (Channel allocation in the 5 GHz band)." To "When using 40 MHz channels, it can only operate in the channels defined in 20.3.14.2 (Channel allocation in the 5 GHz band)." Also change other places in the draft that imply operation with 40 MHz channels in 2.4 GHz spectrum. John R. Barr, Motorola

May 2007 Coexistence History IEEE 802.11 (IEEE Std 802.11™-1999) was the incumbent wireless standard when IEEE 802.15.1 (Bluetooth) was proposed as the first WPAN standard. (IEEE Std 802.15.1™-2002) IEEE 802.15.2 Coexistence Task Group formed to resolve coexistence issues between 802.11 and 802.15.1 resulting in IEEE Std 802.15.2™-2003 (Coexistence of Wireless Personal Area networks with Other Wireless Devices Operating in Unlicensed Frequency Bands): “Because both IEEE Std 802.11b-1999 and IEEE 802.15.1-2002 specify operations in the same 2.4 GHz unlicensed frequency band, there is mutual interference between the two wireless systems that may result in severe performance degradation.” AFH (Adaptive Frequency Hopping) implemented by the Bluetooth SIG to improve coexistence with 802.11 devices: Detects presence of 20MHz 802.11 transmissions Removes hopping channels overlapping with that 20MHz John R. Barr, Motorola

Bluetooth® Wireless Technology Deployment May 2007 Bluetooth® Wireless Technology Deployment As of November 2006, over 1 Billion Bluetooth-enabled devices have been shipped. Over 13 million new Bluetooth-enabled devices are being produced every week. In 2009, over 1 Billion new Bluetooth-enabled devices are expected to be shipped. All of these Bluetooth-enabled devices shipped since release of the v1.2 Bluetooth specification include AFH. A typical high-tech mobile phone user typically owns four Bluetooth-enabled devices (phone, headset, laptop, automobile) John R. Barr, Motorola

Bluetooth Use Case Example May 2007 Bluetooth Use Case Example Typical airport lounge (SFO Admirals Club): In an 100x100 foot area there are the following: 5-10 people using their laptops on a T-Mobile 802.11 Hot-Spot 1-2 of the laptop users are also talking on their mobile phones using a Bluetooth headset while they are typing 5-10 other people talking on their mobile phones using a Bluetooth headset. None of the Bluetooth-enabled devices are co-located with an 802.11 device Laptop users and Bluetooth headset users do not notice any significant interference due to use of AFH by the Bluetooth devices. John R. Barr, Motorola

Issues with 40 MHz 802.11n Channels May 2007 Issues with 40 MHz 802.11n Channels Bluetooth AFH only designed to detect and avoid 20 MHz 802.11 channels. 1 Billion devices and counting… If Bluetooth devices do not detect 40 MHz 802.11n channels due to lower power levels, then there are twice as many opportunities for a Bluetooth device to interfere with the 802.11n signal Use of 40 MHz 802.11n in an area where Bluetooth-enabled devices are operating will significantly degrade their performance John R. Barr, Motorola

May 2007 Recommendation The Bluetooth SIG implemented AFH in their v1.2 release based on IEEE Std 802.15.2™-2003 in order to peacefully coexist with IEEE 802.11 deployments. If 802.11n does not remove the ability to use 40 MHz channels in the 2.4 GHz spectrum, 802.11n should implement a non-collaborative method of detecting the presence of Bluetooth-enabled devices to prevent the use of 40 MHz channels in order to peacefully coexist with Bluetooth-enabled devices. It is probably easier to just not allow use of 40 MHz channels in the 2.4 GHz spectrum. John R. Barr, Motorola

References IEEE Std 802.11™-1999 IEEE Std 802.15.1™-2002 May 2007 References IEEE Std 802.11™-1999 IEEE Std 802.15.1™-2002 IEEE Std 802.15.2™-2003 John R. Barr, Motorola