1. doc.: IEEE 802.22-08/0265r1 Submission Nov. 2008 Cheng Shan, Samsung Electronics Slide 1 BS-to-BS CBP Communication IEEE P802.22 Wireless RANs Date: 2008-11-14 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 802.22-08/0265r1 Submission Nov. 2008 Cheng Shan, Samsung Electronics Slide 2 Abstract This contribution explains why BS-to-BS CBP communication is necessary and proposes the necessary SCW design and corresponding text change to allow BS-to-BS CBP transmission. This contribution is a proposed resolution for comment #406

3. doc.: IEEE 802.22-08/0265r1 Submission Review on CBP Protocol A special beacon protocol for inter-BS communication CBP packet could be transmitted by either CPE or BS during the SCW, which is scheduled by BS at the end of a US frame CBP takes 2~3 OFDM symbols, SCW takes 4~5 OFDM symbol to add buffers before and after CBP transmission –The buffer before CBP is used for contention resolution –The buffer after CBP is used for propagation delay absorption Nov. 2008 Cheng Shan, Samsung Electronics Slide 3

4. doc.: IEEE 802.22-08/0265r1 Submission Why BS-to-BS Direct CBP Transmission is Necessary? (1) In [1], it has been shown that the probability that CBP packet could be exchanged by a pair of CPE heavily relies on the number of CPEs in a cell; BS-to-BS direct CBP transmission is much more reliable because of the good propagation channel characteristics; –CBP transmitted by a BS can be received by another BS more than two times of the BS radius Nov. 2008 Cheng Shan, Samsung Electronics Slide 4

5. doc.: IEEE 802.22-08/0265r1 Submission Why BS-to-BS Direct CBP Transmission is Necessary? (2) BS must send and detect CBP by itself when: –a BS is powered up and has no associated CPEs, neighbor discovery, necessary coexistence protocol, and self declaration must be done by BS itself; –CBP sent by associated CPEs could not be received by any BSs; or associated CPEs cannot receive any CBPs from neighbors; –BS1 is switched to a channel where another BS2 already in operation, and the coexistence protocol could not be accomplished before the BS1 vacate the previous channel; BS1 must detect and communicate with BS2 directly since no transmission from its CPEs is allowed before the resource negotiation is accomplished. Nov. 2008 Cheng Shan, Samsung Electronics Slide 5

6. doc.: IEEE 802.22-08/0265r1 Submission SCW Requirement – 4W BS To allow two BSs to communicate with each other with up to 49km –N*164μs buffer is needed before the CBP packet N is an integer indicating the number of contention back-off slots; (N ≥1) Each back-off slot should at least be 164 μs long to allow BS-to-BS collision detection –Another 164μs buffer is needed after the CBP packet to absorb the propagation delay In total, minimum 328 μs (1~2 OFDM symbols) buffer needed Nov. 2008 Cheng Shan, Samsung Electronics Slide 6

7. doc.: IEEE 802.22-08/0265r1 Submission SCW Requirement – 100W BS To allow two BSs to communicate with each other with up to 76.6km –N*256μs buffer is needed before the CBP packet –Another 256μs buffer is needed after the CBP packet to absorb the propagation delay In total, minimum 512 μs (2~3 OFDM symbols) buffer needed Nov. 2008 Cheng Shan, Samsung Electronics Slide 7

8. doc.: IEEE 802.22-08/0265r1 Submission Proposed Text Change Nov. 2008 Cheng Shan, Samsung Electronics Slide 8 Table 61 ……… Number of symbols1 2 bitNumber of symbols for the coexistence window at the end of the frame including the one symbol buffer before the CBP packet and one symbol buffer following the CBP packet to absorb the propagation time. 0: 4 symbol SCW 1: 5 symbol SCW 2-3: Reserved (Note: SCW in passive mode, i.e., UIUC=1, shall always be 5 symbols) ………

9. doc.: IEEE 802.22-08/0265r1 Submission References [1] 22-08-0198-00-0000-CBP-Success-Probability Nov. 2008 Cheng Shan, Samsung Electronics Slide 9