1. doc.: IEEE 802.22-06/0086r0 Submission June 2006 Jianwei Zhang, Huawei Slide 1 IEEE P802.22 Wireless RANs Date: 2006-06-08 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 Authors: Overhead Reduction for Downstream Bursts

2. doc.: IEEE 802.22-06/0086r0 Submission June 2006 Jianwei Zhang, Huawei Slide 2 Co-Authors:

3. doc.: IEEE 802.22-06/0086r0 Submission June 2006 Jianwei Zhang, Huawei Slide 3 Motivation 1.Heterogeneous traffic leads to variable-length packets - as large as data packets (~>200 bytes). - as small as VoIP packets (~20 – 40 bytes).  Overhead reduction desired for small packets. 2.Possible optimization of the current architecture 1  Flexibility & Integrity required.  Low complexity desired. 1 referred to the draft, IEEE P802.22/D0.1, published in May 2006.

4. doc.: IEEE 802.22-06/0086r0 Submission June 2006 Jianwei Zhang, Huawei Slide 4 Main Features of Our Proposed Structure Refined DS-MAP messageRefined DS-MAP message -provides extra design degree of freedom, -flexible and fully compatible with the existing protocols, -at apparently no cost: - no additional overheads and negligible implementation complexity increase. MAC Header CompressionMAC Header Compression -flexible and fully compatible with the existing protocols, -pure compression with no extra fields required, -~10% reduction for VoIP applications. *** All the above are free! ***

5. doc.: IEEE 802.22-06/0086r0 Submission June 2006 Jianwei Zhang, Huawei Slide 5 Proposal - Refined DS-MAP message (1) Current DS-MAP message (Table 30) Depends on the DS-MAP_IE().  not required if DS-MAP_IE() meets the byte boundary, SyntaxSize DS-MAP_Message_Format() { Management Message Type = 18 bits Synchronization Field16 bits DCD Count8 bits BS ID48 bits Begin PHY Specific Section { for (i = 1; i  n; i++) { DS-MAP_IE()variable } } If (! byte boundary) Padding Nibble4 bits }

6. doc.: IEEE 802.22-06/0086r0 Submission June 2006 Jianwei Zhang, Huawei Slide 6 Current DS-MAP_IE (Table 32) Byte-processing is desirable.  DS-MAP_IE() will ALWAYS meet the byte boundary.  Padding Nibble is not required for the previous table (Table 30). Always required if (DIUC != 15).  can be exploited more meaningfully. Only 3 bits if (INCLUDE_CID != 1). SyntaxSize DL-MAP_IE () { DIUC4 bits If (DIUC == 15) Extended DIUC Dependent IEvariable else{ If (INCLUDE_CID){ N_CID7 bits for (i=0; i<N_CID;i++) CID16 bits } Channel Offset7 bits Number of Channels7 bits Slot Offset8 bits Number of Slots8 bits Boosting3 bits } If ! (byte boundary) Padding Nibble4 bits } Proposal - Refined DS-MAP message (2)

7. doc.: IEEE 802.22-06/0086r0 Submission June 2006 Jianwei Zhang, Huawei Slide 7 Our proposed DS-MAP message (to replace Table 30) SyntaxSize DS-MAP_Message_Format() { Management Message Type = 18 bits Synchronization Field16 bits DCD Count8 bits BS ID48 bits Begin PHY Specific Section { for (i = 1; i  n; i++) { DS-MAP_IE()variable } } If (! byte boundary) Padding Nibble4 bits } Proposal - Refined DS-MAP message (3)

8. doc.: IEEE 802.22-06/0086r0 Submission June 2006 Jianwei Zhang, Huawei Slide 8 Our proposed DS-MAP_IE (to replace Table 32) SyntaxSize DL-MAP_IE () { DIUC4 bits If (DIUC == 15) Extended DIUC Dependent IEvariable else{ If (INCLUDE_CID){ Reserved1 bit N_CID7 bits for (i=0; i<N_CID;i++) CID16 bits } Channel Offset7 bits Number of Channels7 bits Syntax (cont’d)Size Slot Offset8 bits Number of Slots8 bits Boosting3 bits Reserved3 bits } If ! (byte boundary) Padding Nibble4 bits } Proposal - Refined DS-MAP message (4)

9. doc.: IEEE 802.22-06/0086r0 Submission June 2006 Jianwei Zhang, Huawei Slide 9 Proposal – MAC Header Compression (1) Proposed DS-MAP_IE SyntaxSize DL-MAP_IE () { DIUC4 bits If (DIUC == 15) Extended DIUC Dependent IEvariable else{ If (INCLUDE_CID){ C_HDR1 bit N_CID7 bits for (i=0; i<N_CID;i++) CID16 bits } Channel Offset7 bits Number of Channels7 bits SyntaxSize General_MAC_Header_Format() { EC1 bits Type6 bits Reserved3 bits EKS2 bits UCS1 bit CN8 bits Length11 bits If (C_HDR != 1){ CID16 bits } HCS8 bits } Proposed Generic MAC Header C_HDR initialized as 0, updated only if INCLUDE_CID=1.

10. doc.: IEEE 802.22-06/0086r0 Submission June 2006 Jianwei Zhang, Huawei Slide 10 -possible repeated CIDs present in both DS-MAP_IE & Generic MAC Header. - DS-MAP transmission is robust.  CID can be omitted (set C_HDR=1) in Generic MAC Header provided that: (i) INCLUDE_CID = 1 for that DS-MAP_IE. (ii) There is only one MAC PDU per user 1 present in the same data burst specified by a single DS-MAP_IE. - Fully backward compatible with the original Generic MAC Header (set C_HDR =0). 1 0.8Mbps, 1.6Mbp and, 3.2Mbps are achieved for the presence of a single MAC PDU of size 2k bytes in a single frame of sizes 20ms, 10ms and 5ms, respectively. Proposal – MAC Header Compression (2)

11. doc.: IEEE 802.22-06/0086r0 Submission June 2006 Jianwei Zhang, Huawei Slide 11 Scenarios considered*: Bursty Traffic 1. Bursty Traffic (e.g. Internet telnet service/Email service) - Geometrically Distributed with mean 90 bytes, which are lower-bounded by 25 bytes and upper-bounded by 256 bytes. 2. Sporadic Data Traffic (e.g. Upstream web traffic) - Fixed 90 bytes. 3. Bursty and Bulky Traffic (e.g. Web browsing, FTP) - Fixed 480 bytes. *the packet distribution in a typical corporate network based on 802.11b (of comparable bandwidth) is shown that over 60% of time the packet size is of only 44 bytes or even smaller, according to: “Determining a Wireless LAN Access Point’s Station Capacity”, http://www.bandspeed.com/technology/wp_client_capacity_white_paper_1.11.phtml Performance (1) – MAC Header Compression

12. doc.: IEEE 802.22-06/0086r0 Submission June 2006 Jianwei Zhang, Huawei Slide 12 Performance (2) – MAC Header Compression Smooth Traffic 4. VoIP (Voice Data + 2-byte cRTP) - VoIP1 (4.75kbps AMR): Fixed 21 bytes. - VoIP2 (6.7kbps AMR): Fixed 26 bytes. - VoIP3 (12.2kbps AMR): Fixed 40 bytes. 5. Variable-rate data traffic (e.g. compressed video) - Geometrically Distributed with Mean 180 bytes, which are lower-bounded by 50 bytes and upper-bounded by 512 bytes. 6. MTU of Ethernet LAN - Fixed 1500 bytes. 1

13. doc.: IEEE 802.22-06/0086r0 Submission June 2006 Jianwei Zhang, Huawei Slide 13 Performance (3) – MAC Header Compression Packet length statistics of Internet telnet service/Email service (LB=25 bytes, UB=256 bytes).

14. doc.: IEEE 802.22-06/0086r0 Submission June 2006 Jianwei Zhang, Huawei Slide 14 Performance (4) – MAC Header Compression Packet length distribution of Internet telnet service/Email service (LB=25 bytes, UB=256 bytes).

15. doc.: IEEE 802.22-06/0086r0 Submission June 2006 Jianwei Zhang, Huawei Slide 15 Performance (5) – MAC Header Compression Packet length statistics of compressed video (LB=50 bytes, UB=512 bytes).

16. doc.: IEEE 802.22-06/0086r0 Submission June 2006 Jianwei Zhang, Huawei Slide 16 Performance (6) – MAC Header Compression Percentage of overhead reduction in MAC PDUs with our CID-removal technique.

17. doc.: IEEE 802.22-06/0086r0 Submission June 2006 Jianwei Zhang, Huawei Slide 17 Performance (7) – MAC Header Compression Percentage of overhead reduction in MAC PDUs with our CID-removal technique.

18. doc.: IEEE 802.22-06/0086r0 Submission June 2006 Jianwei Zhang, Huawei Slide 18 Complexity Consideration - Negligible increase of implementation complexity:  The receiver ASIC has to look at the DS-MAP_IE (of variable length originally) before it can handle the burst, with both the original scheme and our proposed one.  The complexity in the process of detecting the extra indicator C_HDR in DS-MAP_IE is immaterial.  With our scheme, after the ASIC has processed the DS-MAP_IE, it will know whether there are CIDs or not in the MAC PDUs.