1. Project: 802.11n TG High Throughput WLAN
Month 2002
doc.: IEEE /xxxr0
November 2004
Project: n TG High Throughput WLAN
Submission Title: [ n Comparison of proposals from TGn Sync and WWiSE with suggested evaluation additions ]
Date Submitted: [November, 2004]
Source: [John Egan, Rodger Tseng, Albert Liu] Company [Infineon Technologies]
Address: [ ]
Voice:[ Egan: , Tseng & Liu: ]
[ \, ]
Re : []
Abstract:[This document proposes potential changes to what usage and applications should be considered for proposal analysis (effects document “ n-usage-models” IEEE /802r12) and a brief analysis of differences between the proposals from TGn Sync and WWiSE]
Purpose:[To improve the TG’s ability to determine the best route forward while also keeping market/end user requirements in mind as part of the analysis]
Notice:[This document has been prepared to assist the IEEE P802.11n. It is offered as a basis for discussion and is not binding on the contributing or supporting 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. Based on changes the list of supporters may increase or decrease.]
Release: [The contributors acknowledge and accept that this contribution becomes the property of IEEE and may be made publicly available by P ]
John Egan, Rodger Tseng, Albert Liu, Infineon Technologies
John Doe, His Company

2. November 2004
Overview
There should be more Use and Application cases. Here, we suggest three areas for inclusion. Eventual analysis of proposals must include verification against agreed upon scenarios.
The TGn Sync and WWiSE proposals were analyzed by Infineon. The other proposals were not analyzed due to resource and time constraints, not due to an Infineon view that they do not have merit consideration.
John Egan, Rodger Tseng, Albert Liu, Infineon Technologies

3. Topics Usage Additions based on Applications
November 2004
Topics
Usage Additions based on Applications
(Speaker : John Egan)
TGn Sync & WWiSE Comparisons on PHY (Speaker : Rodger Tseng)
TGn Sync & WWiSE Comparisons on MAC (Speaker : Albert Liu)
Summary
John Egan, Rodger Tseng, Albert Liu, Infineon Technologies

4. Use and Applications Additions
November 2004
Use and Applications Additions
Speaker: John Egan
John Egan, Rodger Tseng, Albert Liu, Infineon Technologies

5. Use and Applications Additions
November 2004
Use and Applications Additions
PDA
Low power receiver and transmitter
Operating at edge of service area
Requires sleep mode for n module
Mobile while in session
Must not lose session
Streaming or random packets
Unidirectional for most streaming
Bidirectional for random
John Egan, Rodger Tseng, Albert Liu, Infineon Technologies

6. Use and Applications Additions
November 2004
Use and Applications Additions
Wireless PAD
Envisioned to be mobile screen pad, next generation of Tablet PCs of today
Battery powered so must have power conservation mode
Mobile while in sessions
Video conference and streaming video required so must be bidirectional and requires error correction based on session type
John Egan, Rodger Tseng, Albert Liu, Infineon Technologies

7. Session Mobility Has this been covered in simulations?
November 2004
Session Mobility
Has this been covered in simulations?
Is this similar to “Measuring the Impact of Slow User Motion on Packet Loss and Delay over IEEE b Wireless Links” submitted to b by Christian Hoene, André Günther, Adam Wolisz of the Technical University of Berlin?
Must include this in comparison simulations
John Egan, Rodger Tseng, Albert Liu, Infineon Technologies

8. TGn Sync & WWiSE Comparisons on
November 2004
TGn Sync & WWiSE Comparisons on
PHY
Speaker: Rodger Tseng
John Egan, Rodger Tseng, Albert Liu, Infineon Technologies

9. Throughput enhancement
November 2004
Features T W
Bandwidth extension
20MHz  40MHz mode
(M) 20MHz mode
(M) 40MHz, whenever regulatory
domain permits this extension
(M) 20 MHz mode
(O) 40 MHz mode
MIMO-OFDM-SDM
(M) 2 spatial streams
@ 20MHz mode
(M) 2 spatial streams
Guard interval (GI) shortening ( 0.8us  0.4us )
(M)
(N)
Higher code rate (R)
(M) R= ½, 2/3, ¾, 7/8
(M) R= ½, 2/3, ¾, 5/6
Higher order modulation scheme
(O) 256 QAM (ABF-MIMO mode)
Adaptive modulation
(O) Bit loading (+ 256 QAM)
+ power weighting (ABF-MIMO)
Reserve more data tones
(M) 48 (4 20MHz
(M) 108 (6 40MHz
(M) 54 (2 20MHz
(O) 108 (4 40MHz
(M) Mandatory (O) Optional (N) Not available
John Egan, Rodger Tseng, Albert Liu, Infineon Technologies

10. Throughput comparison (Maximum achievable uncoded data rate @ 64QAM)
November 2004
Throughput comparison (Maximum achievable uncoded data 64QAM) T W
20 MHz BW + 2 Tx
(M) (R=3/4)
(M) (R=7/8 with ½ GI)
(M) (R=3/4)
(M) ( R=5/6 )
20 MHz BW + 4 Tx
(O) (R=7/8 with ½ GI)
(O) ( R=5/6 )
40 MHz BW + 2 Tx
(M) (R=3/4 )
(M) (R=7/8 with ½ GI)
(O) (R=3/4)
(O) (R=5/6)
40 MHz BW + 4 TX
(O) (R= 7/8 with ½ GI)
(O) (R=5/6 )
(M) Mandatory (O) Optional
Observations:
(1). T > W, between “R=7/8 with ½ GI” for T and “R=5/6” for W.
(2). W >= T, at “ R=3/4 & 2Tx”
John Egan, Rodger Tseng, Albert Liu, Infineon Technologies

11. Performance improvement
November 2004
Performance improvement
Features T W
Bandwidth extension
(M)
(O)
Mandatory coding scheme
(M) Convolutional code
(M) Convolutional code
Advanced Coding scheme
(O) LDPC
(O) RS+Conv (removed)
(O) LDPC
(O) Turbo
Duplicate 40 MHz
(O) 6Mbps BPSK, (R = ½)
(N)
Spatial processing
Eigenvector steering (ES)
Spatial spreading (SS)
(O) SVD_MIMO
(O) Walsh+CS
Space Time Block Code (STBC)
(M) Mandatory (O) Optional (N) Not available
John Egan, Rodger Tseng, Albert Liu, Infineon Technologies

12. Observations & conclusions before further detailed analysis
November 2004
Observations & conclusions before further detailed analysis
Features T W
Preamble format
Neat
More Efficient (shorter)
MIMO Channel estimation
Simple
Needs more adders for interpolations
Spectrum
Fewer null sub-carriers around 40MHz mode
20MHz mode
Throughput (for long packets
under identical MAC efficiency)
Higher, if “R=7/8 & ½ GI” is employed.
Higher, at “R=3/4 & 2 Tx”
claimed Performance for reference 2X2, 64QAM, R=3/4, 20MHz)
0.3dB ch-D (full GI, CC67)
0.3dB AWGN (CC59)
0.8dB ch-B (T: 1/2GI , CC67)
Gate count (Mandatory mode)
Slightly lower due to simpler channel estimation
Slightly higher
Optional features
Many
Few
Proposal stability & Completeness
Sensitivity & EVM proposals are still missing
Better
John Egan, Rodger Tseng, Albert Liu, Infineon Technologies

13. Suggestions & comments
November 2004
Suggestions & comments
Further extensive simulations are needed to identify
performance under identical conditions to enable
fair comparisons.
As both proposals employ mandatory and basic
MIMO-OFDM-SDM architecture in constructing
their modems, there exist possibility for harmonization
and convergence in the future.
John Egan, Rodger Tseng, Albert Liu, Infineon Technologies

14. TGn Sync & WWiSE Comparisons on
November 2004
TGn Sync & WWiSE Comparisons on
MAC
Speaker: Albert Liu
John Egan, Rodger Tseng, Albert Liu, Infineon Technologies

15. Feature comparisons November 2004 TGn Sync WWiSE NOTE
New definition in general frame N Y
TGn Sync has higher design complexity.
New control frames
New data frame
New mgt frame
Aggregation
Several frames can be put together
MP(S)DU
Control frames can be also aggregated in TGn Sync.
A-MSDU aggregation
Several A-MSDUs can be aggregated in WWiSE.
Scheme
Complex
Simple
TGn Sync needs IAC/RAC to initialize aggregation.
WWiSE needs one bit in QC to initialize aggregation.
John Egan, Rodger Tseng, Albert Liu, Infineon Technologies

16. Feature comparisons (Con’t)
November 2004
Feature comparisons (Con’t)
TGn Sync
WWiSE
NOTE
receivers
multiple
direction
unidirection/bi-direction
unidirection
Bi-direction can have little interactive latency
Performance
(no header compression)
normal
better
(w/ header compression)
A-PPDU length
limited Bytes
unlimited
WWiSE uses one bit in PLCP header to identify which PPDU is the last one.
Power saving modes
good
TGn Sync uses MRAD, receivers NOT inside aggregated frame can shut down their RF for power saving.
John Egan, Rodger Tseng, Albert Liu, Infineon Technologies

17. Preamble + PLCP headers + SIFS will be saved
November 2004
What is aggregation ?
Legacy Burst
PSDU1
PSDU2
PSDU3
Preamble
PLCP
header
MPDU
Header
MPDU
Payload
Preamble
PLCP
header
MPDU
Header
MPDU
Payload
Preamble
PLCP
header
MPDU
Header
MPDU
Payload
FCS
FCS
FCS
Perform
aggregation
SIFS
SIFS
Preamble
+ PLCP
Header
A-PSDU
Preamble + PLCP headers + SIFS will be saved
Some overheads will be induced to identify each MP(S)DU
John Egan, Rodger Tseng, Albert Liu, Infineon Technologies

18. MPDU Delimiter + PAD induce 4B ~ 7B per MPDU
November 2004
TGn Sync Aggregation
Pad to 4 bytes
MPDU1
MPDU2
MPDU3
Preamble
+ PLCP
Header
A-PSDU
Max PSDU Length = B
RSV/LEN/CRC/UP
One mechanism can find next correct MPDU
delimiter when the current one is broken 4B
MPDU Delimiter + PAD induce 4B ~ 7B per MPDU
John Egan, Rodger Tseng, Albert Liu, Infineon Technologies

19. TGn Sync Header Compression
November 2004
TGn Sync Header Compression
Suggestion: No need HID
FC/DRU/a1/a2/a3/SC/QC
26B
Uncompressed
header
MPDU1
MPDU2
MPDU3
Perform
header
compression
CHDATA header
FC/SC/HID/RSV
MHDR MPDU
30B
FC/DRU/a1/a2/a3/HID/RSV/QoS/FCS 6B
CHDATA header can save 26B-6B = 20B per MPDU
John Egan, Rodger Tseng, Albert Liu, Infineon Technologies

20. TGn Sync Aggregation + Header Compression
November 2004
TGn Sync Aggregation + Header Compression
MHDR MPDU
CHDATA MPDU1
CHDATA MPDU2
CHDATA MPDU3
CHDATA
Header
CHDATA
Payload
CHDATA
Header
CHDATA
Payload
CHDATA
Header
CHDATA
Payload
MHDR
MPDU
A-PSDU
Induced 4~7B
Saved 20B
Saved - induced = 13B~16B per MPDU are saved
John Egan, Rodger Tseng, Albert Liu, Infineon Technologies

21. SF-Header can save 26B-14B = 12B per MSDU
November 2004
WWiSE Aggregation
SF-Header
A-MSDU
A-PSDU
MSDU1 payload
MSDU2 payload
MSDU3 payload
A-MSDU Header
Preamble + PLCP header
LEN/SA/DA
ZIFS+PLCP header
(8K)
14B
Suggestion1: enlarge A-MSDU
Suggestion2 : SF-header needs CRC
if suggestion 1 is applied
MSDU headers 26B are saved
 NOTE: PLCP header can NOT be efficiently saved
SF-Header can save 26B-14B = 12B per MSDU
John Egan, Rodger Tseng, Albert Liu, Infineon Technologies

22. Aggregation Comparison Table
November 2004
Aggregation Comparison Table
TGn Sync
WWiSE
1) Saved preamble
Yes
2) Saved PLCP headers
3) Saved SIFS
4) Saved MP(S)DU headers
5) Extra
IAC
MPDU Delimiters
PAD
HID
compressed headers
sub -frame headers
6) Saved
MPDU header is replaced by CHDATA header
MSDU header is replaced by Sub-frame header
John Egan, Rodger Tseng, Albert Liu, Infineon Technologies

23. November 2004
Case Study – TGn Sync
case 1 : Assume 24 MPDU (2KB), 1TX, 64QAM, 3/4 , --> 54Mbps ,
No aggregated consumes : 24 preambles + 24 PLCP headers + 24 MPDU headers + 24 MPDUs + 23 SIFSs = 8006 us
Aggregated + header compression are applied:
aggregated consumes : 1 preambles + 1 PLCP headers + 24 MPDU delimiters + 1 MPDU header + 1 HID + 24 compressed headers+ 24 MPDUs + {23 PAD octets} + IAC (40B)
1) 23 preambles are saved = 23 * 16us = 368us are saved.
2) 23 PLCP header are saved, 23*4us = 92us are saved.
3) 23 SIFSs are saved = 23 * 10us = 230 us are saved.
4) 23 MPDU header are saved = 23 * 26 = 598 bytes are saved
5)extra (1 HID) and ( 24 compressed headers) and (24 * MPDU Delimiters) and (23 PAD octets) + IAC are consumed = 1 + ( 6 * 24) + ( 4 * 24) + ( 3 * 23) +40 = 350 byte are wasted
analysis 4) and 5) : (( )*8)/216 = 10 symbols = 40 us are saved
conclusion : = 730 us are saved
Performance improved : 730us / 8006us = 9.12%
John Egan, Rodger Tseng, Albert Liu, Infineon Technologies

24. November 2004
Case Study – WWiSE
case 1 : Assume 24 MSDU (2KB) = 6 * A-MSDU, 1TX, 64QAM, 3/4 , --> 54Mbps ,
No aggregated consumes : 24 preambles + 24 PLCP headers + 24 MSDU headers + 24 MSDUs + 23 SIFSs = 8006us
Aggregated is applied :
aggregated consumes : 1 preambles + 6 PLCP headers + 6 MSDU headers + 24 sub-frame headers + 24 MSDUs
1) 23 preamble are saved if all are ZIFS = 23 * 16us = 368us are saved
2) 18 PLCP headers are saved = 18 * 4us = 72us are saved
3) 23 SIFSs are saved = 23 * 10us = 230us are saved.
4) 18 MSDU headers are saved.
5) extra 24 sub -frame headers.
Analysis (worst case):
One A-MSDU = ((14B*4- 26B*3 ) *8 )/216 = 0 symbols, total 6A-MSDU = 0 symbols = - 0us are saved
conclusions : = 670 us are saved
Performance improved = 670/8006 = 8.37%
John Egan, Rodger Tseng, Albert Liu, Infineon Technologies

25. Comparison table for Case Study
November 2004
Comparison table for Case Study
TGn Sync
WWiSE
1) Saved preamble 23
2) Saved PLCP headers 18
3) Saved SIFS
4) Saved MP(S)DU headers
5) Extra
(1 HID) and ( 24 compressed headers) and (24 * MPDU Delimiters) and (23 PAD octets)+ IAC
extra 24 sub -frame headers
4) – 5)
(( )*8)/216 = 10 symbols = 40 us are saved
One A-MSDU = ((14B*4- 26B*3 ) *8 )/216 = 0 symbols, total 6A-MSDU = 0 symbols = - 0us are saved
Total saved time and %
730us %
670us %
Item 4 and 5
need to
be balanced
John Egan, Rodger Tseng, Albert Liu, Infineon Technologies

26. Performance Comparison
November 2004
Performance Comparison
1) TGn Sync performance is better than WWiSE when aggregation + header compression is performed.
I.e. (case1)125*2KB packets => TGn Sync/WWiSE = 1.100
I.e. (case2) 24* 2KB packets => TGn Sync/WWiSE = 1.090
I.e. (case3) 120*1KB packets => TGn Sync/WWiSE = 1.044
I.e. (case4) 24* 1KB packets => TGn Sync/WWiSE = 1.034
I.e. (case5) 8* 1KB packets => TGn Sync/WWiSE = 1.000
2) TGn Sync performance is worse than WWiSE when only aggregation is performed.
i.e. (case1) 125*2KB packet => TGn Sync/WWiSE = 0.997
I.e. (case2) 24* 2KB packet => TGn Sync/WWiSE = 0.982
I.e. (case3) 120* 1KB packet => TGn Sync/WWiSE = 0.946
I.e. (case4) 24* 1KB packet => TGn Sync/WWiSE = 0.932
I.e. (case5) 8* 1KB packet => TGn Sync/WWiSE = 0.900
John Egan, Rodger Tseng, Albert Liu, Infineon Technologies

27. Conclusion When there are more aggregated packets, regardless of size
November 2004
Conclusion
When there are more aggregated packets, regardless of size
When higher air speed (more bits inside one symbol)
The dominant factor will be the number of PLCP headers.
Improvements to Aggregation need to be in the final n definition to achieve best performance
page15
John Egan, Rodger Tseng, Albert Liu, Infineon Technologies

28. Suggestions to these 2 campaigns
November 2004
Suggestions to these 2 campaigns
(1) To TGn Sync:
Topic : Remove HID in MHDR MPDU and CHDATA MPDU.
Reason: For implementation feasibility, one MHDR MPDU should be often followed by same a1/a2/a3’s CHDATA MPDU.
Benefit: save one byte HID may possibly save 4 bytes of padding in each MPDU.
Drawback: continuous MHDR MPDU with different HID are forbidden.
(2) To WWiSE:
Topic1 :Enlarge A-MSDU size to 256KB.
Reason: save more PLCP headers in A-PSDU
Benefit : save more PLCP headers mean more air time is saved.
Drawback: different address set (a1/a2/a3) should be separated by another A-PSDU.
Topic2: Sub frame header should have CRC and develop one mechanism can find next correct sub frame header when current one is broken if topic 1 is applied.
Reason: make sure this header is right. One sub frame header is fail, all the A-MSDU is fail.
Benefit: One sub-frame header is fail, but the rest of sub-frame can still help.
Drawback: Implementation overload.
John Egan, Rodger Tseng, Albert Liu, Infineon Technologies

29. Month 2002
doc.: IEEE /xxxr0
November 2004
Summary
More Use and Application cases need to be considered for a full analysis of proposals. This analysis needs to be scheduled.
Both TGn Sync and WWiSE proposals have strengths and weaknesses. We recommend an effort to resolve these through some form of merger.
The market should get as strong and technologically advanced a standard as possible to promote the next wave of consumer and in-premise distribution beyond traditional LAN devices
John Egan, Rodger Tseng, Albert Liu, Infineon Technologies
John Doe, His Company