Coexistence for Multiple WRAN Cells Nov. 2008 doc.: IEEE 802.22-yy/xxxxr0 Nov. 2008 Coexistence for Multiple WRAN Cells IEEE P802.22 Wireless RANs Date: 2008-11-08 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. > Cheng Shan, Samsung Electronics

Nov. 2008 doc.: IEEE 802.22-yy/xxxxr0 Nov. 2008 Abstract This contribution proposes an air interface for more than two coexisting WRAN cells to negotiate channel/frame sharing Cheng Shan, Samsung Electronics

Inter-Channel Sharing Coexistence Mode Nov. 2008 Inter-Channel Sharing Coexistence Mode Multiple cells may reuse the same channel N When a cell try to obtain channel N for operation, it must be wait until all neighboring cells operating on channel N agree to release channel N Cheng Shan, Samsung Electronics

Inter-Frame Sharing Coexistence Mode Nov. 2008 Inter-Frame Sharing Coexistence Mode If multiple co-located cells have to share one TV channel, they need to share it in a TDD manner and granularity of sharing is one frame; It is preferable that the co-located cells share the frames based on a negotiated pattern on a per super-frame basis Two faraway cells may reuse the same frame to improve spectrum efficiency Cheng Shan, Samsung Electronics

Nov. 2008 Exemplary Scenario Cheng Shan, Samsung Electronics

Channel/Frame Multi-Negotiation - Conditions Nov. 2008 Channel/Frame Multi-Negotiation - Conditions Cells negotiate frame allocation through mechanisms such as frame renting/offering, and frame contention etc. Similar mechanisms as channel renting/offering and channel contention, can be applied. When a cell is trying to request a frame from neighbors, the desired frame might be occupied by multiple neighbor cell In this case, the source cell shall send multiple requests to multiple neighbor cell that are occupying the desired frame, and only occupy the frame when permitted by all its destination cells. Cheng Shan, Samsung Electronics

Channel/Frame Multi-Negotiation - Air Interface Nov. 2008 Channel/Frame Multi-Negotiation - Air Interface The CBP messages could be carrying channel/frame renting/offering, or channel/frame contention. Step 1: source sends C/F-REQ to neighbor cells, this could be broadcasting or multicasting; Step 2: destination receives the C/F-REQ and generates response C/F-RSP to it according to a certain algorithm (renting/offering, or contention, etc) If the C/F-REQ was broadcasted, the source cell can judge if response to it is necessary by checking if the requested channel/frame is an active frame of present cell or not; Step 3: destination cells feed back their response to source cell during their scheduled SCW respectively; Step 4: after collecting all responses, the source cell judge if the request is successful or not, and then sends an ACK/NACK to corresponding destination cell for confirmation The request can only be successful when all destination cells agree to release the frame; Step 5: all related BS apply the operational channel/frame change from the negotiated start time. Cheng Shan, Samsung Electronics

Exemplary Process for Frame Negotiation @ Source Cell Nov. 2008 Exemplary Process for Frame Negotiation @ Source Cell Cheng Shan, Samsung Electronics

Exemplary Process for Frame Negotiation @ Destination Cell Nov. 2008 Exemplary Process for Frame Negotiation @ Destination Cell Cheng Shan, Samsung Electronics

Nov. 2008 Appendix: D-SCH vs. SFN The following slides compare the operational steps for D-SCH and SFN, after negotiating on a certain frame under coexistence mode The comparison gives an overview on how much delay may be incurred after the negotiation protocol and before the new frame scheduling can be actually applied. Cheng Shan, Samsung Electronics

Nov. 2008 Effect for D-SCH (1) Source cell and destination cells negotiate on frame 3 Source cell win frame 3 Cheng Shan, Samsung Electronics

Nov. 2008 Effect for D-SCH (2) Source cell and destination cells apply new frame allocation from the negotiated timing, earliest from next super frame. Cheng Shan, Samsung Electronics

Nov. 2008 Effect for D-SCH (3) Other neighbor cells may occupy frame 3 if it is classified as locally available These neighbor cells use back-off time to contend frame 3 Cheng Shan, Samsung Electronics

Effect for SFN (1) Same first procedures Nov. 2008 Effect for SFN (1) Same first procedures Source cell and destination cells negotiate on frame 3 Source cell win frame 3 Cheng Shan, Samsung Electronics

Nov. 2008 Effect for SFN (2) At least one super-frame’s delay needed for CBP propagation At least two super-frames’ delay needed if acknowledgement is necessary New frame scheduling must be forwarded through CBP to all coexisting cells before it can actually applied Cheng Shan, Samsung Electronics

Nov. 2008 Effect for SFN (3) Complex protocol shall be introduce to resolve the conflicting frame request Though possible, other cells cannot occupy frame 3 before being agreed upon by all coexisting cells Cheng Shan, Samsung Electronics