1. doc.: IEEE 802.22-07/0503r0 Submission October 2007 Wendong Hu, STMicroelectroncisSlide 1 Parallel Data Services and Spectrum Sensing with Cognitive Channel Switching IEEE P802.22 Wireless RANs Date: 2007-10-22 Authors: Notice: This document has been prepared to assist IEEE 802.22. 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 802.22. Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures http://standards.ieee.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 Chairhttp://standards.ieee.org/guides/bylaws/sb-bylaws.pdf Carl R. StevensonCarl R. Stevenson 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 802.22 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at patcom@iee.org.patcom@iee.org >

2. doc.: IEEE 802.22-07/0503r0 Submission October 2007 Wendong Hu, STMicroelectroncisSlide 2 Abstract This presentation reviews the serial scheduling method currently considered for spectrum sensing of WRAN and, particularly discusses the WRAN service interruption issues of using this method for TG1 beacon payload capture. An alternative scheduling approach for WRAN, which allows parallel spectrum sensing and data services therefore eliminates the need for scheduling lengthy long quiet time and channel switching time, is proposed.

3. doc.: IEEE 802.22-07/0503r0 Submission October 2007 Wendong Hu, STMicroelectroncisSlide 3 TG1 Beacon Detection in Series with Data Services (1) No channel switching if no protection is needed MSF detection time: 40~100ms

4. doc.: IEEE 802.22-07/0503r0 Submission October 2007 Wendong Hu, STMicroelectroncisSlide 4 TG1 Beacon Detection in Series with Data Services (2) Channel switching is scheduled if protection is needed Channel move time: up to 2000ms; Channel setup time: up to 2000ms;

5. doc.: IEEE 802.22-07/0503r0 Submission October 2007 Wendong Hu, STMicroelectroncisSlide 5 Issues with the Serial TG1-beacon Detection and Data Services Assumptions –TG1 beacons are regularly deployed in the area where WRANs are deployed. Otherwise, the impact of TG1 beacon detection on WRAN operations are negligible. –TG1 deployments are equally likely on a large set of TV channels. Otherwise, database approach would be more desirable. Services are interrupted when TG1 beacon’s payloads are being captured. –For capturing MSF1, 40ms of continuous interruption is needed. –For capturing MSF1+MSF2, 70ms of continuous interruption. –Fore capturing MSF1+MSF2+MSF3, ~100ms of continuous interruption. Services are interrupted when channel switching is performed. –Up to 2000ms of channel move time on the old channel, and –Up to 2000ms of channel setup time on the new channel. –No data service is allowed during these periods. One-time channel switching can’t solve the problem for very long.. –Same issues will likely happen on the channel that a WRAN has just switched to. –Beacon aggregation only happens on co-channel.

6. doc.: IEEE 802.22-07/0503r0 Submission October 2007 Wendong Hu, STMicroelectroncisSlide 6 An Alternative Approach – TG1 Beacon Detection in Parallel with Data Services No in-band long quiet period for beacon payload capture, which are done out-of-band. Time allowed for data services after a TG1 beacon sensing period –If a beacon sync-burst is detected, it is the shorter of the remaining time of the channel maintenance interval and the maximally allowed interference time –Else – it’s the remaining time of the channel maintenance interval. System-wise fast channel switching is the key!!!

7. doc.: IEEE 802.22-07/0503r0 Submission October 2007 Wendong Hu, STMicroelectroncisSlide 7 Zero-delay (System-wise) Channel Switching The WRAN cell performs periodic channel maintenance on a set of actively switching channels that are initially setup, such that switching delays for channel closing, channel opening, and channel availability check are eliminated. Hardware switching time on each device is typically less than 1ms, therefore is negligible.

8. doc.: IEEE 802.22-07/0503r0 Submission October 2007 Wendong Hu, STMicroelectroncisSlide 8 Zero-delay (System-wise) Channel Switching

9. doc.: IEEE 802.22-07/0503r0 Submission October 2007 Wendong Hu, STMicroelectroncisSlide 9 Conclusion Serial spectrum sensing (TG1 beacon detection) with data transmissions poses the issue of continuously interrupting data services for TG1 payload capture. WRAN operations scheduled persistently on a single channel worsen the service interruption issue further, due to the costly system-wise channel switching delay. The concept of parallel data services and out-of-band spectrum sensing is proposed. This new approach enables the WRAN system to satisfy the requirements for both TG1 beacon capture and WRAN QoS. As a critical enabling technique, a system-wise fast channel switching method for WRAN is also shown to be feasible.