On-demand EOBS for hidden incumbent reporting June 2006 doc.: IEEE 802.22-yy/xxxxr0 June 2006 On-demand EOBS for hidden incumbent reporting IEEE P802.22 Wireless RANs Date: 2006-06-15 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 Chair Carl 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. > Ang Chee Wei, Institute for Infocomm Research Ang Chee Wei, Institute for Infocomm Research

June 2006 doc.: IEEE 802.22-yy/xxxxr0 June 2006 Abstract We propose an extension to the EOBS (Explicit Out-Band Signaling) scheme so that the out-band signaling is turned on only upon occurrence of the hidden incumbent situation. Ang Chee Wei, Institute for Infocomm Research Ang Chee Wei, Institute for Infocomm Research

Content Overview of the hidden incumbent situation June 2006 Content Overview of the hidden incumbent situation Overview of the EOBS scheme On-demand EOBS Calculation on signaling overhead saving Ang Chee Wei, Institute for Infocomm Research

Overview of the hidden incumbent situation (1/2) June 2006 Overview of the hidden incumbent situation (1/2) CPE Rx Affected CPEs (interfered by incumbent transmission) No interference to incumbent receivers BS/CPE Rx BS/CPE Sensing BS Tx Incumbent Tx Incumbent Rx (incumbent receivers are located inside this contour) Incumbent Rx Normal detection region Incumbent receivers are not interfered by BS CPEs in the dot-shaded region are interfered by the incumbent transmission BS cannot detect the incumbent transmission directly CPEs in the slash-shaded region are able to detect and report the incumbent transmission Ang Chee Wei, Institute for Infocomm Research

Overview of the hidden incumbent situation (2/2) June 2006 Overview of the hidden incumbent situation (2/2) CPE Rx Incumbent receivers interfered by BS Interference to incumbent receivers Affected CPEs BS/CPE Rx BS Sensing BS Tx Incumbent Tx Incumbent Rx (incumbent receivers are located inside this contour) Incumbent Rx Normal detection region Incumbent receivers in horizontal-line-shaded region are interfered by BS CPEs in the slash-shaded region are able to detect and report the incumbent transmission, but if this region is small as shown there might not be any CPE in this region, and the incumbent receivers continue to be interfered by the BS Ang Chee Wei, Institute for Infocomm Research

Overview of the EOBS scheme June 2006 Overview of the EOBS scheme BS to transmit control messages in several out-of-operating-bands (“out-bands”) periodically: When a CPE finds that it loses synchronization with the BS, and that it sensed an incumbent transmission (“affected CPE”), it looks for the out-band broadcasts to gain synchronization and then send the report The EOBS proposal defines these functionalities: Searching and synchronizing to an out-band channel upon hidden incumbent detection Method of acquiring uplink resource for sending report, e.g. pre-assigned US resource during network entry, or by contention Report format Ang Chee Wei, Institute for Infocomm Research

June 2006 On-Demand EOBS To reduce the signaling overhead of periodic transmission of out-band broadcasts, we propose to turn on EOBS only on-demand The BS is signaled by the affected CPEs to turn on the out-band broadcasts (EOBS) in this way: The affected CPEs send out a special tone in one of the unused channels (list as specified by BS) The special tone comprises of a set of sub-carriers turned on as specified by the BS The BS picks up this signal during its out-of-band sensing. Upon detecting that it is the special tone, the BS turns on EOBS. EOBS takes over from here The affected CPEs will switch off after a timeout if they do not hear the EOBS broadcast EOBS is switched off after BS makes decision in response to the report If there is no unused channel, the tone is sent in-band. The BS picks up the signal during in-band sensing. In this case EOBS is not turned on, the BS has to make decision without detail report Ang Chee Wei, Institute for Infocomm Research

On-demand EOBS (at the CPE) June 2006 On-demand EOBS (at the CPE) Ang Chee Wei, Institute for Infocomm Research

On-demand EOBS (at the BS) June 2006 On-demand EOBS (at the BS) Ang Chee Wei, Institute for Infocomm Research

Calculation on signaling overhead saving June 2006 Calculation on signaling overhead saving Number of candidate channels = x Mean arrival rate of a hidden incumbent = a Broadcast message time length = c Inter-EOBS broadcast time = s Average tone duration before EOBS is turned on = b Average total signaling time from arrival of an hidden incumbent to transmission of report for EOBS and OD-EOBS = tEOBS, tOD-EOBS Ang Chee Wei, Institute for Infocomm Research

Calculation on signaling overhead saving June 2006 Calculation on signaling overhead saving If x = 3, c = 10ms, s = 1s, a = 1/day, b = 1s, overhead_saving = 99.96% Ang Chee Wei, Institute for Infocomm Research

June 2006 Tone design 1 channel Each WRAN uses a different set of sub-carriers within the channel to represent the special tone. The CPEs and BS within the same WRAN can identify this special tone. The BS shall identify his signal and make decision to turn on our-of-band broadcast. Neighboring BSs that detect this signal shall ignore it. Ang Chee Wei, Institute for Infocomm Research