WLAN Coexistence Liaison Report

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1 TR Hewlett-Packard Company Worldwide Technical Regulations ====================================================================== Title: WLAN Coexistence Liaison Report Distribution: All members of the TIA TR Subcommittee. Date: 18 August 2003 Source: Scott Roleson, P.E. Tel: Hewlett-Packard Company FAX: West Bernardo Drive San Diego, CA USA WWW: Keywords: TR , TIA, Telecom, WLAN, RLAN, , Bluetooth Notices: The contributor grants a free, irrevocable license to the Telecommunications Industry Association (TIA) to incorporate text or other material contained in this contribution and any modification thereof in the creation of a TIA publication; to copyright and sell in TIA's name any TIA publication even though it may include all or portions of this contribution; and at TIA's sole discretion to permit others to reproduce in whole or in part such contribution or the resulting TIA publication. The contributor is willing to grant licenses under such copyrights to third parties on reasonable, non-discriminatory terms and conditions for a TIA publication which incorporates this contribution. This contribution was prepared to assist TIA Working Group TR , and is offered as a basis for discussion and is not to be construed as a binding proposal on the Hewlett- Packard Company (HP) or its author. HP specifically reserves the right to amend or modify the material contained herein. Nothing herein shall be construed as conferring or offering licenses or rights to any intellectual property of HP other than that provided in the copyright statement above. Use of the information in this document is strictly at the user's discretion. Neither the compiler nor HP guarantee this information in any way, nor are responsible for its use. The contributor knows of no applicable patents or copyrights relating to this information. ======================================================================= Introduction: This paper was written to facilitate liaison between the TIA TR working group and others on the subject of wireless device coexistence. Activities over the last few months of the IEEE Coexistence TAG are summarized, and brief reports on the WFA Coexistence TG and the DARPA XG project are given. WLAN Coex Liaison Rpt TR Page 1

2 This paper was intended as a helpful reference on the issue of coexistence between cordless telephones, wireless local area networks (WLANs), and other devices that share the same frequency bands. Particular attention is given to those systems operating in the 2.4 and 5.8 GHz ISM bands, and the U-NII frequencies in the 5 GHz region. Interested readers will hopefully find this document to be informative, but they are encouraged to not rely exclusively on this paper as their only source of information on this topic. While every effort has been made to ensure accuracy, no guarantee is given nor implied for any of the content of this document. IEEE 802 Coexistence Activities: Chaired by Jim Landsford of Mobilian Corporation, the IEEE Coexistence Technical Advisory Group (TAG) works to address issues of wireless coexistence with existing standards and standards under development, with the greatest emphasis on those from 802 wireless committees. A Web site and reflector are maintained to facilitate this committee s work at: committee documents and working papers are archived at: Live meeting and frequent teleconferences - IEEE had a face-to-face meeting in Dallas in May. Progress was made on the charter and operating rules. Cooperation and liaison with coexistence efforts in other 802-series committees was discussed. Conference calls were also held in June and July, continuing the work started in Dallas. Spectrum Etiquette According to Steve Whitesell, the setting of some sort of spectrum etiquette between WLANs and cordless phones was discussed during the meeting in May. While some thought it may be a bit too late for the 2.4 GHz band, spectrum etiquette may still be a possible coexistence technique in the 5.8 GHz band. Usage Models - Work continues within several 802 groups including on defining a set of WLAN usage models that will hopefully capture expected and realistic deployments of wireless devices in typical applications, and to provide a basis for setting comparison criteria, functional requirements, and metrics. The deliverable is to be a draft document containing 5 or 6 usage models representing situations that have high probabilities of occurring in practice, focusing in particular on interactions among /15/16/20 devices and systems. The models are deliberately agnostic on frequency to deal with multi-band devices, which are already appearing in the marketplace. Usage models are envisioned to have two parts: A deployment environment (e.g., residential, enterprise, hot spot, etc.) A set of applications typically associated with each particular deployment environment. Examples of possible usage models under consideration include: The individual user with a WiFi-enabled laptop PC and a Bluetooth headset. Office users with clusters of cubicals, each with its own independent WiFi piconet. WLAN Coex Liaison Rpt TR Page 2

3 Conference room scenarios, with multiple users, independent piconets, and a Bluetoothenabled speakerphone. Public hot spots (e.g., airport/train/bus stations, stadiums, malls, hotels, convention centers, libraries, etc.) Wireless Cable (e.g., TV/Internet connection via pole-mounted neighborhood APs) The plan going forward was to hold a series of teleconferences about every two weeks, with completion of the final document by September. This work was done in liaison with the IEEE HT and the WPAN groups. The High Throughput Study Group (HT-SG) met on June 17, July 1, and July 15, and is chaired by Adrian Stephens of Intel. (Teleconferences about every two weeks seems to be the norm.) At least 5 or 6 usage scenarios are being discussed, to include residential and enterprise scenarios. Some consideration has been given to separate usage scenarios for 2.4 and 5 GHz applications, and to the inclusion of coexistence as part of the usage models. A draft usage model document was created specifically to support high data rate standards. Coexistence with non equipment is seen as harder to define than those exclusive to One suggestion is that could try to identify the generic characteristics of other classes of devices, such as cordless telephones. Another comment was that any residential coexistence scenario that did not include a cordless telephone is of limited use given the widespread use of cordless phones in North America, but others think this may also be too restrictive a view. Within IEEE committee, the Wireless Personal Area Network (WPAN) Working Group, Task Group 2 (TG2) focuses on WPAN/WLAN coexistence issues. A draft document Coexistence usage models for 15.3a was circulated as a strawman draft. It describes possible traffic types and usage scenarios where a will need to coexist with other wireless standards. (See reference list below for link to this document.) For more information about TG2, see: New IEEE g Standard Ratified: In a June 12 news release, the IEEE s Standards Association announced ratification of the g standard for higher speed wireless LANs. Operating in the 2.4 GHz band, this new standard amends the popular b standard, increasing its raw data rate from 11 to 54 Mbps. Networks using this new amendment will also support four to five times more users, enables more demanding applications, and adds flexibility b and 11g devices can exist simultaneously on the same network. For more information, see the official news release at: Stories on this in the industry press include those at the following URLs: In a separate announcement, a new standard for high rate wireless personal area networks (WPANs) for consumer and portable multimedia devices was also approved in June as IEEE For ordering details, see: WLAN Coex Liaison Rpt TR Page 3

4 New WiFi Alliance Coexistence Task Group: In a separate activity, the WiFi Alliance established a new task group also focused specifically on wireless device coexistence. The mission of this TG is to Ensure an effective environment for efficient and fair usage of unlicensed (new and U-NII) spectrum amongst all users of such a spectrum, Wi-Fi and others, and elevate the position of the Wi-Fi Alliance among industries that share this spectrum. Its objectives include: Quantify the spectrum problem Create criteria for evaluating coexistence proposals Develop coexistence proposals Propose an implementation process May approach regulators via regulatory sub-committee Their initial teleconference was held on June 23, co-chaired by Yoram Solomon (Texas Instruments) and Amer Hassan (Microsoft). An reflector will be set up Requests to subscribe are processed through Corinne Belvel (cbelvel@wi-fi.org). The WiFi Alliance certifies compatibility of WiFi (802.11x) products and promotes WiFi wireless LAN globally. WFA was formerly known as the Wireless Ethernet Compatibility Alliance or WECA. Their Web site is at: DARPA XG Next Generation Initiative: In June the U.S. Defense Advanced Research Projects Agency (DARPA) unveiled their XG or Next Generation initiative. This program hopes to develop technology allowing multiple users to share spectrum through adaptive mechanisms that deconflict users in terms of time, frequency, code, and other signal characteristics. DARPA s goals are to increase spectrum usage by a factor of ten, and to develop technology applicable to both civilian and military use. Another consideration is the reduction in negotiations that the U.S. Department of Defense must engage in worldwide for spectrum access. The concept would create an architecture where radios are independent from the policies which govern them, rather than insisting that radios be designed for a specific policy. The architecture would prevent interference without specifying frequencies or power levels. DARPA set up a Web site to facilitate XG development. While still a work-in-progress, it has links to papers describing the program vision and architectural framework. See these at: References: Roleson, S., Coexistence in 2.4 & 5.8 GHz ISM Bands Backgrounder, document number TR , Newport Beach, 17 February Landsford, Jim, Coexistence usage models for 15.3a, strawman draft shared with committee on 26 June Available at: WLAN Coex Liaison Rpt TR Page 4

5 Recommended Practices for Coexistence of Wireless Personal Area Networks with Other Wireless Devices Operating in Unlicensed Frequency Bands, from IEEE , reportedly was recently approved as an IEEE standard. This focuses on coexistence between Bluetooth and devices. "Interference Evaluation of Bluetooth and IEEE b Systems," from the U.S. National Institute of Standards and Technology (NIST) explores interference issues of using these systems in close proximity. Ideas for adjusting various parameters to minimise interference are given. See: Acknowledgements: The author would like to acknowledge and thank Jim Lansford and the members of IEEE , and the other committees mentioned above, for their contributions to this paper. # # # WLAN Coex Liaison Rpt TR Page 5

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