1. doc.: IEEE 802.22-06/0204r0 Submission October 2006 Ramon Khalona, Nextwave Broadband, Inc.Slide 1 Channel Aggregation Summary IEEE P802.22 Wireless RANs Date: 2006-10-10 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 IEEEs name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEEs 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 802.22-06/0204r0 Submission October 2006 Ramon Khalona, Nextwave Broadband, Inc.Slide 2 Abstract This is a summary of the Channel Aggregation (CA) proposal (currently an optional feature in the standard draft) that highlights key concepts of the proposal and some of the advantages over the Channel Boding proposal made by Philips

3. doc.: IEEE 802.22-06/0204r0 Submission October 2006 Ramon Khalona, Nextwave Broadband, Inc.Slide 3 Example of Two Aggregated Channels OFDMA Frame in Two Aggregated Channels

4. doc.: IEEE 802.22-06/0204r0 Submission October 2006 Ramon Khalona, Nextwave Broadband, Inc.Slide 4 Downlink Construction

5. doc.: IEEE 802.22-06/0204r0 Submission October 2006 Ramon Khalona, Nextwave Broadband, Inc.Slide 5 Key Characteristics of Channel Aggregation Each of the aggregated channels retains its identity and can be added or dropped incrementally as spectrum becomes available Aggregated channels need not be contiguous (as for channel bonding) Allows single channel CPEs to coexist with CPEs that can implement CA oblivious to the fact that aggregation is happening Higher rates/throughput can be multiplexed across aggregated channels as a load balancing operation Total flexibility for asymmetric traffic (i.e., DL could use CA while UL could remain in single channel mode)

6. doc.: IEEE 802.22-06/0204r0 Submission October 2006 Ramon Khalona, Nextwave Broadband, Inc.Slide 6 PHY It is envisioned that channels being aggregated will retain their individual PHY layers (i.e., there will be as many PHYs as channels being aggregated) Each PHY instance is equivalent to a single channel implementation (single channel OFDMA parameters, as opposed to using larger FFT size for channel bonding)

7. doc.: IEEE 802.22-06/0204r0 Submission October 2006 Ramon Khalona, Nextwave Broadband, Inc.Slide 7 MAC Two possibilities

8. doc.: IEEE 802.22-06/0204r0 Submission October 2006 Ramon Khalona, Nextwave Broadband, Inc.Slide 8 Advantages of Single MAC approach A single MAC managing the multiple aggregated channels can easily maintain QoS while scheduling traffic from a channel aggregation capable CPE, including from an individual connection, across multiple PHYs A single MAC also allows better use of resources via statistical multiplexing of the multiple PHYs, placing data on whichever PHY has bandwidth for aggregation capable CPEs. Which PHY has bandwidth available will dynamically change based on demand from CPEs that are not capable of aggregation, as well as demand from aggregation capable CPEs A single MAC can reduce latency in channel aggregated mode due to efficient use of statistical multiplexing/load balancing by balacing QoS and bandwidth demands with available resources (i.e., less constrained than multiple MACs) A single MAC can more efficiently use ARQ to guarantee or maximize in- order packet reception. This problem is aggravated with Multiple MAC, unless a connection is constrained to an individual channel, in which case peak throughputs are compromised

9. doc.: IEEE 802.22-06/0204r0 Submission October 2006 Ramon Khalona, Nextwave Broadband, Inc.Slide 9 Conclusions Channel Aggregation is superior to Channel Bonding when spectrum availability is uncertain. Channels are aggregated or dropped incrementally as they become available or need to be vacated. Aggregated channels need not be contiguous Unlike Channel Bonding, Channel Aggregation allows single channel CPEs to coexist with Channel Aggregation-capable CPEs in a transparent fashion (i.e., oblivious to the fact that aggregation is happening) We advocate implementation of a single MAC for Channel Aggregation in view of the benefits stated on the previous slide