1. doc.: IEEE 802.19-05/0026r0 Submission July 2005 Stephen R Whitesell, VTech CommunicationsSlide 1 Cordless Telephone Coexistence Considerations Notice: This document has been prepared to assist IEEE 802.19. 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 IEEEs name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEEs 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 802.19. Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures, 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 TAG 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 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 802.19 TAG. If you have questions, contact the IEEE Patent Committee Administrator at.http:// ieee802.org/guides/bylaws/sb-bylaws.pdfpatcom@ieee.org Date: 2005-07-20 Authors:

2. doc.: IEEE 802.19-05/0026r0 Submission July 2005 Stephen R Whitesell, VTech CommunicationsSlide 2 Abstract Basic characteristics of cordless telephones operating in the unlicensed 2.4 and 5.8 GHz ISM bands are discussed. Coexistence analyses of proposed IEEE 802 standards that include operation in these bands should take these characteristics into account.

3. doc.: IEEE 802.19-05/0026r0 Submission July 2005 Stephen R Whitesell, VTech CommunicationsSlide 3 Cordless Telephone Technologies Analog Digital –Frequency Hopping Spread Spectrum (FHSS) –Direct Sequence Spread Spectrum (DSSS) –Other Digital Modulation Techniques

4. doc.: IEEE 802.19-05/0026r0 Submission July 2005 Stephen R Whitesell, VTech CommunicationsSlide 4 Analog Telephones Operating under Part 15.249 of the FCC Rules Frequency Bands –2.4 GHz (2400 to 2483.5 MHz) –5.8 GHz (5725 to 5875 MHz) Field Strength –50 mV/m measured at 3 m Other Characteristics –Narrow band FM –Paired handset and base transmitting on separate frequencies –Multiple frequencies available, but only one pair in use at a time –Changes frequencies to avoid interference

5. doc.: IEEE 802.19-05/0026r0 Submission July 2005 Stephen R Whitesell, VTech CommunicationsSlide 5 Digital Telephones Operating under Part 15.247 of the FCC Rules Frequency Bands –2.4 GHz (2400 to 2483.5 MHz) –5.8 GHz (5725 to 5850 MHz)* Power –Limit is 1.0 W, except –Limit for 2.4 GHz FHSS using less than 75 channels is 0.125 W –Typical is 0.25 W or less Other Characteristics –Depends on modulation method and (sometimes) on frequency band * 5.8 GHz upper band limit for digital under Part 15.249 is 25 MHz lower than for analog under Part 15.247

6. doc.: IEEE 802.19-05/0026r0 Submission July 2005 Stephen R Whitesell, VTech CommunicationsSlide 6 FHSS Systems using WDCT* Chipsets Characteristics –95 channels, 864 kHz spacing, 800 kHz typical bandwidth –75 channels in hop set, 20 reserve channels can be swapped out –TDD system with eight 1.25 ms time slots per 10 ms frame (four TX slots and four RX slots) –100 Hz hop rate (1 frame per hop) –Supports simultaneous use of up to four handsets Alternative Characteristics for WiFi Aware Phones –Reduced number of channels in hop set, 17 typical –Allowed only in 2.4 GHz band * Worldwide Digital Cordless Telecommunications

7. doc.: IEEE 802.19-05/0026r0 Submission July 2005 Stephen R Whitesell, VTech CommunicationsSlide 7 WDCT Time Slot Assignments

8. doc.: IEEE 802.19-05/0026r0 Submission July 2005 Stephen R Whitesell, VTech CommunicationsSlide 8 WDCT Operation Base unit uses TS0 to transmit a dummy bearer or beacon signal. Slots TS3 & TS7 are used as the traffic bearers for the first handset engaged, TS2 & TS6 for the second handset, TS1 & TS5 for the third handset, and TS0 and TS4 for the fourth handset. TS0 carries both beacon signal and traffic for fourth handset if four handsets are engaged. Traffic moves to higher numbered slots as handsets become disengaged. That is, TS3 & TS7 are always used by handset that has been engaged longest.

9. doc.: IEEE 802.19-05/0026r0 Submission July 2005 Stephen R Whitesell, VTech CommunicationsSlide 9 FHSS WDCT 2-Handset Example

10. doc.: IEEE 802.19-05/0026r0 Submission July 2005 Stephen R Whitesell, VTech CommunicationsSlide 10 WDCT Coexistence Mechanisms Swap out channels on which interference is detected. WiFi Aware 2.4 GHz telephones will try moving to another area of the band if an 802.11b or 802.11g WLAN is detected.

11. doc.: IEEE 802.19-05/0026r0 Submission July 2005 Stephen R Whitesell, VTech CommunicationsSlide 11 References FCC Part 15 Rules