July 2006 doc IEEE 802 22 060121 r

July 2006 doc. : IEEE 802. 22 -06/0121 r 1 Channel Sensing Based on Self-Signal Suppression (SSS) IEEE P 802. 22 Wireless RANs Date: 2006 -07 -19 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. > Submission 1 Baowei Ji, Samsung

July 2006 doc. : IEEE 802. 22 -06/0121 r 1 Abstract A novel channel sensing scheme is proposed based on selfsignal suppression/cancellation, which allows in-band channel sensing without the requirements for quiet periods. The optimized tradeoff could be achieved between spectral utilization and the reliability of in-band channel sensing by combining SSS-based channel sensing with on-demand scheduling of quiet periods or dynamic channel hopping. Submission 2 Baowei Ji, Samsung

July 2006 doc. : IEEE 802. 22 -06/0121 r 1 Motivation • Traditional thinking on inband channel sensing: Requirement for quiet period. – Periodically/opportunistically scheduling quiet periods – Dynamic frequency hopping. • The proposal is based on self-signal suppression (SSS): – Detect the self signal – Cancel the self signal – Sense over the remaining signal • No requirement for quiet period during regular operation (ideally). • Almost any sensing algorithm can be applied after self signal suppression. Submission 3 Baowei Ji, Samsung

July 2006 doc. : IEEE 802. 22 -06/0121 r 1 Illustration of SSS Wireless Channel Received Signals Channel Estimation Submission Self-Signal Detection Self-Signal Reconstruction 4 Channel Sensing over the Remaining Signal Baowei Ji, Samsung

July 2006 doc. : IEEE 802. 22 -06/0121 r 1 No Interference Signal Before SSS Interference Signal Emergence After SSS Before SSS P 1 After SSS Self Signal Remaining Signal P 1 Self Signal P 3 Noise Floor IU Protection Zero Noise Submission P 2 P 3 IU Signal P 2 Suppression Residual Signal 5 Baowei Ji, Samsung

July 2006 doc. : IEEE 802. 22 -06/0121 r 1 Operation Signal Received Normal retransmission protocols Self-Signal Detected No Data Integrity Check Passed? No Maximum Trials Reached? Yes Self-Signal Reconstruction Channel Possibly Occupied Self-Signal Suppression Channel Sensing over the Remaining Signal Submission Channel management 6 Baowei Ji, Samsung

July 2006 doc. : IEEE 802. 22 -06/0121 r 1 Feasibility/Complexity for Implementation • Only two blocks are unique to SSS. – Self-signal reconstruction – Self-signal cancellation • The residual self signal level should be below the Incumbent User signal level (possibly below the noise floor). • Self-signal could be removed completely in the baseband if the channel estimation is ideal. Submission 7 Baowei Ji, Samsung

July 2006 doc. : IEEE 802. 22 -06/0121 r 1 Enhancements: Reliable Channel Estimation Preamble Downlink Burst FCH, DL-MAP, UL-MAP Uplink Burst Received Data Channel Estimation Based on a Single Frame The channel is assumed to be stable over multiple frames Submission 8 Accumulation/Averaging Over Multiple Frames To Improve Channel Estimation Baowei Ji, Samsung

July 2006 doc. : IEEE 802. 22 -06/0121 r 1 Other Enhancements • The BS can do channel sensing over all the UL bursts. • A CPE can do channel sensing over other CPE’s DL bursts, besides its owns, because any CPE has the capacity to use the whole channel. However, the CPE won’t require for retransmission of other CPEs’ data if signal detection fails. • Both the BS and CPEs can do long-time channel sensing over the remaining signals of multiple frames in order to increase the reliability and accuracy of channel sensing. Submission 9 Baowei Ji, Samsung

July 2006 doc. : IEEE 802. 22 -06/0121 r 1 Optimal Channel Sensing Scheme Having moved to a new channel. SSS-based Channel Sensing (regular operation without any IU or other LE signals) Channel is probably occupied. Channel is clear. Quiet Time-based Channel Sensing (quiet time scheduling or DFH) (on-demand feature) Submission 10 Channel moving Channel is occupied. Baowei Ji, Samsung

July 2006 doc. : IEEE 802. 22 -06/0121 r 1 Conclusions • This method is in parallel with other in-band channel sensing methods that are based on quiet period or DFH. • Advantages of uninterrupted channel estimation. • Advantages of uninterrupted self-signal transmission. • The potential optimal method: SSS-based, plus ondemand quiet-time scheduling and / or DFH. Submission 11 Baowei Ji, Samsung