January 2005 doc.:IEEE 802.11-05/1595r1
IEEE P802.11
Wireless LANs
Date: 2005-01-17
Author(s):
Name / Company / Address / Phone / email
Garth Hillman / Advanced Micro Devices / 5204 East Ben White
Austin TX 78741
MS: 625 / (512) 602-7869 /
Executive Summary (also see Chairs’ closing report doc. 11-05-0082r0):
1. Qualcomm declared support for nSync Alliance and withdrawal of their complete proposal citing both proposals had similar features (support BF).
2. Mitsubishi withdrew their support from the MitMot Alliance and declared their support for the nSync Alliance.
3. Motorola declared that they would be the sole sponsor of the MitMot proposal and declared the name now stood for Mac and mImo Techniques for MOre Throughput.
4. Updates to the three remaining proposals – nSync, WWiSE and MITMOT – were made; comparison presentations were made by proposers and non-proposers; significant written and oral Q&A time was provided.
5. A down selection vote was conducted with the following result:
a. nSync – 132 (55.32%)
b. WWiSE – 84 (35.15%)
c. MITMOT – 23 (9.62%)
The MITMOT proposal was thereby eliminated from further consideration at this time. Note that it could be reconsidered if a 75% confirmation vote is not achieved.
6. Sheung Li from Atheros was elected as Vice-Chair.
7. Nominations were opened for the technical editor. Election will take place at the March Plenary meeting.
8. Informal meeting was held with .19 (coexistence); .11n will have to attach a Coexistence Assurance document with the initial LB draft supplement; the rules surrounding the .19 CA process were reviewed.
9. Next meeting – March 14-18 in Atlanta; goals are to have a down selection vote and, if possible a confirmation vote and elect a technical editor.
Note: relative to presentations, these minutes are intended to offer a brief summary (including document number) of each of the presentations to facilitate review and recall without having to read each of the presentations. Most of the ‘presentation related’ minutes are built directly from selected slides of the various presentations and therefore are not subjective. An effort was made to note obscure acronyms.
The Q&A was particularly hard to capture and is subjective. Again this meeting Aryan Saed helped the secretary capture the essence of the Q&A. Please contact the secretary regarding errors and omissions.
1. 20 submissions were received and are listed in doc. 11-03-0891r3
2. Four conference calls will be held before the January meeting
3. Goal of January meeting will be to issue a “call for proposals”
Detailed cumulative minutes follow:
Monday, January 17, 2005; 4:00 PM – 9:30 PM [~ 212 attendees];
1 Meeting was called to order by Task Group chairperson elect Bruce Kraemer at 4:00 PM
2 Chairs’ Meeting Doc 11-04-1531r0
3 Chair read IEEE Patent Policy and recent interpretation by PAT COM
4 Chair reviewed topics not to be discussed during the meeting – licensing, pricing, litigation, market share
5 New participants in .11n ~= 20
6 Status update since SA Nov meeting
7 Motion by Jon Rosdahl to approve Nov minutes was seconded by Adrian Stephens passed without comment
8 Announcements
8.1 John Ketchum officially declared Qualcomm has joined the nSync Alliance
8.2 Jinyun Zhang officially declared Mitsubishi has joined the nSync Alliance
8.3 Marc de Courville officially declared Motorola would continue with the MitMot proposal which has been renamed Mac and mImo Techniques for MOre Throughput
9 Floor requested that freed up time be allocated to comparison presentations; chair agreed
10 Floor asked for clarification on why non-member names (e.g., MitMot) are being used to label presentations etc? Chair responded that those were the names of accepted alliances and special rules were not being used
11 Chair then proceeded to negotiate the Weeks’ Agenda for .11n and addressed the following topics:
11.1 Chair reviewed agenda logic agreed to at the San Antonio meeting
11.2 Chair presented an overview of the written questions
11.3 Chair reviewed options
11.3.1 Use Qualcomm freed up time for comparison presentations? Decision – comparison presentations
11.3.2 Should Wed Q&A be scheduled under special orders? Decision – no
11.3.3 Thursday Panel? Decision by Straw Poll – retain panel (41), sacrifice panel (63)
11.3.4 Should Thursday Down Selection vote be scheduled under special orders? Decision – yes at 1:30 PM
11.3.5 Chair asked if there was anyone who wanted the down selection vote to be a roll call vote (i.e., the votes are made public); someone from the floor said they would ask for a roll call vote.
11.3.6 A Straw Poll was held to determine if there was at least 25% support for a roll call vote with the result that 42 said yes (43%) and 55 said no (57%); The chair indicated the down selection vote would be a roll call vote
11.3.7 Comparison Presentations were grouped into those presented by non-proposer authors (4)
11.3.7.1 Field Measurements of 2x2 MIMO Communications, Babak Daneshrad, UCLA, 05-1627
11.3.7.2 TGn Consensus Proposal, HP & Infineon, 05-1625
11.3.7.3 Service Provider Requirements, Bellsouth & Qwest, 05-1644
11.3.7.4 Beamforming and MAC, Aryan Saed
11.3.7.4.1 Aryan Saed volunteered give his paper on Thursday after the down selection vote
11.3.8 Comparison Presentations were grouped into those presented proposer authors (10) which are:
11.3.8.1 Comparison of Value of proposed MAC features, Adrian Stephens, 05-1634
11.3.8.2 Closed vs Open Loop Comparisons, John Ketchum, 05-1630
11.3.8.3 1579 - ACI
11.3.8.4 1581 – Preamble Power Variations
11.3.8.5 1616 – WWiSE Pilot Performance
11.3.8.6 1645 – Preambles, Beam Forming for WWiSE
11.3.8.7 1590 – Legacy Effects of WWiSE Preambles
11.3.8.8 1636 – Pilot Tones
11.3.8.9 1635 – Preambles and MIMO Beam Forming – Sadowsky
11.3.8.10 05-006 – Backward Compatibility of CDD Preambles
11.3.8.11 Total available time = 4.5 hours so allowed length of time per presentation will be adjusted to the time available
11.4 In preparation for the Vice Chair election scheduled for 1:30 today the chair noted that the only announced candidate was Sheung Li and that the nominations were still open.
11.5 Following Agenda was approved:
12 Presentation: (11-04-1627); by Babak Daneshrad from UCLA; Field Measurements of 2x2 MIMO Communications; outline
12.1 Testbed Overview
12.2 Loss Due to IQ mismatch & phase noise (eye opener for research team)
12.3 Measurement Results (on 8x8 in 25 MHz of BW)
12.4 MIMO Decoder ASIC (6 mm per side)
12.5 Note: ‘common’ phase error (CPE) decreases with increasing FFT sizes and increasing MIMO configuration
12.6 Questions - none
13 Presentation: (11-04-1630r0) by Sanjiv Nanda from Qualcomm; Closed vs Open Loop Comparison
13.1 Quality and Benefits of Closed Loop
13.2 Throughput and Latency Comparison
13.3 Rate vs Range Curves
13.4 Conclusions
13.4.1 We have demonstrated throughput and latency benefits of closed loop feedback.
13.4.1.1 MIMO Mode feedback: Eigen-mode steering versus spatial spreading
13.4.1.2 Stream feedback: number of spatial streams
13.4.1.3 Rate feedback: rates per spatial stream
13.4.2 Significant benefits with very little overhead.
13.4.2.1 16 bits(?) at Data Rate
13.5 Questions from the floor
13.5.1 Did you do experiments to determine the sensitivity of results? A – yes but more work needs to be done
14 Chair recessed the session at 6:03 until 7:30 PM
15 Chair reconvened the meeting at 7:31 PM
16 Chair issued a final call for Vice Chair nominations and Harry Worstell nominated Art Astrin, a professor at San Jose State
17 Chair conducted the election:
17.1 Each candidate gave a brief speech (2 min) outlining their qualifications and reasons for running for election
17.2 It was verified that both candidates met the requirement of being a voting member of .11n
17.3 The candidates left the room for the vote
17.4 The open vote was held and the results were:
17.4.1 Sheung Li (Atheros) = 72
17.4.2 Art Astrin = 32
17.5 Chair introduced Sheung as the new Vice Chair of .11n
18 Comparison Presentation: 11-05-1625r2; 802.11n Consensus Proposal by Tim Wakeley
18.1 Proposed a .11n sub-committee to recommend a process to merge key differences
18.2 Possibly work on mandatory features first and then optional features
18.2.1 Examples include – aggregation, 20/40 MHz, preambles, coding scheme,
18.3 .11n scope is very broad and therefore a process is needed
18.4 Would a ‘line item veto’ be a bad process?
18.5 Chair noted some of these topics should be considered in setting the March agenda
18.6 Open to the floor for comments:
18.6.1 Logical suggestions
18.6.2 Good that members who are NOT affiliated with one or the other group get a voice in the decision
18.6.3 Two proposals are in fact already close together
18.6.4 Can’t get around the .11 process; let it work
18.6.5 75% is difficult to achieve
19 Chair took a moment to draw cards for the order of the 2 hour complete presentation updates starting Tuesday at 10:30 AM. The order turned out to be MitMot, WWiSE and TGnSync.
20 Comparison Presentation: 11-05-1644-00-00n, Service Provider Requirements for 802.11n; Brian Ford, Bell South
20.1 Gateways now include modem, router and AP
20.1.1 GPON = Gigabit Passive Optical Network
20.2 Use .11n to reduce need for truck roll and pulling wires in homes
20.3 Support VoIP; handsets will be dual – GSM and Wi-Fi!!!
20.4 Need customer satisfaction, QoS especially for voice, error free streaming data, PnP, security, 25 Mbps @ 150 Meter drop (as close as fiber must get to the home to be classified as fiber to the home) , Mobility - Doppler Effect, mesh, hand-off,
20.5 Impairments – 3 dB=sheet rock, 6 dB=floor, 9 dB=exterior wall
20.6 Customers prefer a single access point
20.7 Must have QoS – baseline = as good as existing services
20.8 Encryption – need to encrypt content to satisfy Hollywood
20.9 Create device types categorized by packet size capability
20.10 For video conferencing don’t have the luxury of buffering
20.11 VoIP is probably the hardest
21 Comparison Presentation: 11-04-1579r1, Adjacent Channel Interference and Filtering for 56 Carrier Signals; Dave Hedberg, Conexant
21.1 The sharper filter required for 56 carriers results in a 27 tap filter (vs 19 for 52 carriers)
21.2 Conclusion:
21.2.1 ACI performance and filter complexity are not significantly different
21.2.2 The added dispersion due to the required narrower filter transition band for 56-carriers does not significantly impact PER performance with TGn channels
21.3 Questions - none
22 Chair rationalized with members the order of the remaining comparison presentations
22.1 Chris Hansen and John Sadowsky volunteered to make their presentations on Wednesday starting at 1:30
22.2 Cards were drawn to establish the order of the 6 remaining comparison proposals starting Tuesday morning at 8:00 AM
23 No further business so chair recessed the meeting at 9:25 PM until 8:00 AM tomorrow morning
Tuesday 1-18-05; 8:00 AM – 6:00 PM
1 Chair called the meeting to order at 8:01 AM
2 Comparison Presentations by Proposers; 11-05-1634r0, Technical Comparison of the value of proposed MAC features; Adrian Stephens, Intel
2.1 Expectations of a good MAC defined
2.1.1 Balanced perf of phy and MAC
2.1.2 Balanced Complexity
2.1.3 Scaleable and extensible
2.1.4 Meet the needs of Usage models
2.1.5 Exceed proprietary solutions
2.1.6 Interoperable with legacy products
2.2 Benefits of TGnsync
2.2.1 Aggregation
2.2.2 Reverse Direction data
2.2.3 MRMRA – multiple responder multiple receiver aggregation
2.2.4 RX assisted link adaptation
2.3 Comparison with WWiSE
2.3.1 No reverse Direction Data
2.3.2 No MRMRA
2.3.3 With saturated load nSync throughput exceeds WWiSE throughput
2.4 Questions
2.4.1 How does recovery happen if channel fails? A – 3-way handshake
2.4.2 TGe MAC already complex enough? A – TGe never had a timely protocol
3 Comparison Presentations by Proposers; 11-05-0006r1, Backward Compatibility of CDD Preambles; Darren McNamara, Toshiba
3.1 Statement of Problem – both nSync and WWiSE use the CDD technique
3.1.1 CDD – Cyclic Delay Diversity
3.1.2 WWiSE is not fully backward compatible since some legacy devices use auto-correlation and others use cross-correlation; decoding WWISE signal field using WWiSE preamble is problematic for legacy receivers based on cross-correlation
3.1.3 nSync more robust as measured in the lab
3.2 Questions – none
4 Comparison Presentations by Proposers; 11-05-1581r1, Power Variations with WWiSE Cyclic Preamble Structure; Dave Hedberg, Conexant
4.1 Concludes that power variation is well behaved for the WWiSE Preamble and resulted in robust detection
4.1.1 Variation in dynamic range was relatively small with associated minimal degradation in performance
4.1.2 Purpose of mixed mode STS is only for legacy detection
4.1.3 Laboratory testing has been done
4.1.3.1 STS – Short Training Sequence
4.1.3.2 LTS – Long Training Sequence
4.1.3.3 SF – signal field
4.2 Questions – Slide 14, ch E, do you need an extra bit in the ADC? A - no
5 Comparison Presentations by Proposers; 11-05-1616r1,WWiSE Pilot Scheme Performance; Airgo Networks; Allert van Zelst
5.1 Showed that the WWiSE pilot scheme outperformed the legacy .11a pilot scheme while having the same tracking bandwidth (loss at most .5 dB)
5.1.1 One of the best metric – post processing SNR of the pilot processing
5.1.2 From a theoretical point of view it is true that the MIMO 2 pilots out performs SISO 4 pilot case
5.2 Questions – none
6 Comparison Presentations by Proposers; 11-05-1636r1, Impact of Fewer Pilot Tones on .11n PHY Performance; Won-Joon Choi, Atheros
6.1 Simulation conditions=CC67
6.2 Config = 2x2
6.3 Don’t just compare to .11a but also consider:
6.3.1 Timing
6.3.2 Frequency Offset
6.3.3 Channel Estimation
6.3.4 Decoded SNR
6.3.5 Pilot/Phase Tracking accuracy
6.4 Concludes: using only 2 tones to gain <4% throughput has detrimental effects of about 1 dB in PER; also, if one pilot is lost (e.g., narrow band interference from BT) results can be very significant – 6 dB PER