Managing SCW regular pattern July 2007 doc.: IEEE 802.22-yy/xxxxr0 July 2008 Managing SCW regular pattern IEEE P802.22 Wireless RANs Date: 2008-07-16 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. > Sangbum Kim, Samsung Electronics

July 2007 doc.: IEEE 802.22-yy/xxxxr0 July 2008 Abstract This contribution proposed a mechanism for controlling scalability in reservation of SCW This contribution is related to the resolution of comment #436 Comment #436 Sangbum Kim, Samsung Electronics

Reservation of SCW in Draft v1.0 July 2007 doc.: IEEE 802.22-yy/xxxxr0 July 2008 Reservation of SCW in Draft v1.0 BS schedules a SCW in active mode according to a regular pattern. During its initialization stage, a new comer WRAN monitors the channel to discover neighboring WRANs and identifies their SCW regular patterns. The new comer WRAN shall set its own regular pattern so that it does not overlap with the SCWs reserved by the discovered neighboring WRAN. Contention-based & reservation-based Sangbum Kim, Samsung Electronics

Problem on SCW regular pattern July 2008 Problem on SCW regular pattern If there is no vacant SCW slot for new comer, how can the new comer BS transmit its CBP packet? A new value of SCW_Active_Repetition should be set; In current draft, there is no mechanism to manage the value of SCW_Active_Repetition among BSs Sangbum Kim, Samsung Electronics

Distributed management for Reservation of SCW July 2008 Distributed management for Reservation of SCW If all SCW slots are occupied, new comer BS secures its SCW regular pattern by contending a neighboring cell. If new comer loses, it retries to contend in another SCW slot. Otherwise, the target cell shall increase the period of its pattern as double and then share SCW slots with new comer. New comer should try to contend a cell with the small period of SCW_Active_Repetition for fairness of latency performance. If there is vacant SCW slots and the pattern of other cells is not disturbed, cell can reduce its regular pattern. Sangbum Kim, Samsung Electronics

Exemplary process - No vacant SCW slot July 2008 Exemplary process - No vacant SCW slot Sangbum Kim, Samsung Electronics

July 2008 Suggested text changes for SCW regular pattern in ‘6.21.2.1.2 CBP Packet Generation’ The reservation of SCWs facilitates the contention-free CBP transmissions among the neighboring WRAN cells sharing the channel, and it can be achieved by scheduling the regular SCW pattern such that it does not overlap with the SCW pattern of other neighboring WRANs. The procedure for that is as follows:   During the initialization stage, the WRAN monitors the channel to discover neighboring WRANs and identifies their SCW regular patterns. For instance, the regular SCW pattern can be identified by receiving a sequence of CBP packets from a neighboring WRAN. If a WRAN indentifies another WRAN’s regular SCW pattern, it shall regard these SCWs as reserved and shall set its own regular pattern so that it does not overlap with the SCWs reserved by the neighboring WRAN. Once the WRAN starts its own regular SCW pattern, it shall maintain this pattern for a number of super-frames specified by the SCWActive_Reservation_Period parameter. Insert the following texts between line 36 and line 37 If necessary, a BS reserves its SCW regular pattern by contending on an active SCW slot occupied by a existing neighboring cell. If the BS lose the contention, it retries to contend on another active SCW slot; If the existing neighboring cell detects contention from other WRAN cells in a given SCW slot, it shall double the SCW_Active_Repetition value by giving up the contended slot in its reserved pattern. Sangbum Kim, Samsung Electronics

July 2008 Conclusion We proposed a mechanism to manage the period of SCW reservation through contention-based access mechanism which is already adopted in the current draft v1.0. Flexibility and scalability in SCW reservation is allowed. The proposed mechanism needs minimal change to MAC and no change to PHY. Sangbum Kim, Samsung Electronics

July 2008 References IEEE P802.22™/ DRAFTv1.0, Draft Standard for Wireless Regional Area Networks Part 22: Cognitive Wireless RAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: Policies and procedures for operation in the TV Bands Sangbum Kim, Samsung Electronics