1. Hervé Bonneville, Bruno Jechoux, Romain Rollet
Month 2003
doc.: IEEE /xxxr0
MITMOT “Mac and mImo Techniques for MOre Throughput” alliance proposal presentation in response to IEEE802.11n CFP
Hervé Bonneville, Bruno Jechoux, Romain Rollet
Mitsubishi ITE 1, allee de Beaulieu, Rennes, France
Markus Muck, Marc de Courville, Jean-Noël Patillon, Stéphanie Rouquette-Léveil, Alexandre Ribeiro Dias, Karine Gosse, Brian Classon, Keith Blankenship
Motorola Labs
Parc les Algorithmes – Saint Aubin – Gif sur Yvette Cedex - France E. Algonquin Rd, Schaumburg, IL , USA
Jechoux,Patillon Mitsubishi/Motorola
H.Bonneville, B.Jechoux, Mitsubishi ITE

2. Guide to MITMOT Proposal
Month 2003
doc.: IEEE /xxxr0
Guide to MITMOT Proposal
The complete proposal consists of the following four documents:
n-mitmot-tgn-complete-proposal-response
Response to functional requirements, comparison criteria table. Includes also a technical overview
n-mitmot-tgn-complete-proposal-detailed-description
Detailed technical description of the proposal
n-mitmot-tgn-complete-proposal-presentation
This document
n-mitmot-tgn-complete-proposal-sim-results
Detailed system simulation results (Excel spread sheet)
n-mitmot-tgn-complete-proposal-short-presentation
Short overview presentation of the proposal
Jechoux,Patillon Mitsubishi/Motorola
H.Bonneville, B.Jechoux, Mitsubishi ITE

3. Overall goal and positioning
Preserve compatibility with legacy IEEE system
Evolution: expand current WLAN application domain, offer a consistent solution to
Provide required QoS to support consumer electronics (multimedia home environment and VoIP enterprise)
Grant range extension for limited outdoor operation (hotspot) as well as full home coverage
Support heterogeneous traffic: increase overall peak data rate without jeopardizing lower data rates modes
Manage diversity (laptop/PDA/VoIP Phone) and evolution (independent STA/AP antenna configuration upgrade) of devices through asymmetric antenna configurations
Proven and simple solution: combine a highly efficient contention-free based MAC with robust yet low complexity open-loop MIMO PHY techniques
Jechoux,Patillon Mitsubishi/Motorola

4. .11n MAC: an evolutionary approach
Month 2003
doc.: IEEE /xxxr0
.11n MAC: an evolutionary approach
Solutions:
Centralised on demand resource allocation with grouped resource announcements,
embedded in .11e superframe
providing contention free access for all type of .11n traffics
Aggregated PHY bursts made of short fixed size MAC-PDUs
1 or multiple destinations and/or PHY modes
Enhanced ACK: low latency and low overhead selective retransmission
Benefits:
Actual QoS: guaranteed throughput, stringent delay constraints support
even in heavily loaded system
High efficiency and scalable architecture
Scenario SS16 (point to point): 86% - Extended SS6 (Hotspot): 67%
constant overhead when data rate increases
Efficient for heterogeneous traffics (bursty, VBR, CBR, high or low data rates)
without parameter tuning
Easy implementation, low power consumption
summary deck
Jechoux,Patillon Mitsubishi/Motorola
H.Bonneville, B.Jechoux, Mitsubishi ITE

5. .11n PHY: a robust extension to MIMO
Goal: define new OFDM MIMO modes with the constraints to
handle asymmetric TX/RX antenna configurations with 1, 2 or 3 parallel streams
focus on open-loop for stability, avoiding calibration circuit or feedback signalling
Solution: exploit a hybrid combination of
Spatial Division Multiplexing (SDM) to increase spectrum efficiency and peak data rates
classical Space Time Block Coding (STBC) to improve link robustness or range for low to medium data rates (suited to small packet size e.g. VoIP)
Additional key features:
mandatory: 20MHz bandwidth, minimum of 2Tx antennas (up to 4Tx)
new two stage space and frequency interleaver design
Forward Error Correction scheme:
supports all .11a CC rates, adds low redundancy 5/6 (mandatory)
advanced optional scheme: binary turbo code derived from 3GPP
second 20MHz/128 carriers OFDM modulation (8% rate increase), with double duration guard interval (Hotspot: limited outdoor)
optional high rate 40MHz bandwidth/128 carriers modes (117% rate gain)
new nPLCP preambles: code overlay STS/orthogonal LTS
Jechoux,Patillon Mitsubishi/Motorola

6. Typical system performances
All QoS flows satisfied
Scenario XVI: Use the most efficient PHY mode (3x3 256QAM3/4, Ns=3)
(*) bis stands for: “with fully backlogged TCP sources”
Jechoux,Patillon Mitsubishi/Motorola

7. PHY description and link performance
Month 2003
doc.: IEEE /xxxr0
PHY description and link performance
summary deck
Jechoux,Patillon Mitsubishi/Motorola
H.Bonneville, B.Jechoux, Mitsubishi ITE

8. PHY presentation outline
The MitMot PHY layer proposal consists in an extension of IEEE802.11a PHY including several key new features:
20MHz (mandatory), 40MHz (optional) bandwidth
Optional second OFDM modulation using 104 data subcarriers among 128 in 20MHz or 40MHz bandwidth
Multiple TX/RX antenna modes handling asymmetric antenna configuration (2, 3 or 4 transmit antennas, 2 or more receiving antennas)
Frequency and spatial interleaving
Advanced optional forward error correction scheme relying on turbo-codes
Improved preamble design for multi-antenna channel estimation and synchronization purposes
Link quality metric feedback for efficient link adaptation
Simulation Results & Conclusion
Jechoux,Patillon Mitsubishi/Motorola

9. OFDM modulations 2 bandwidths support: 20&40MHz
1st OFDM modulation based on IEEE802.11a for 20MHz
48 data subcarriers, 64-point (I)FFT, 4 pilots
Reference PHY rate: 2TX: 120/144Mbps, 3-4TX: 180/216Mbps
2nd OFDM modulation for 20MHz (optional):
duration of the guard interval and number of carriers doubled (0.8µs 1.6µs) to absorb larger multipath delays with same total overhead (25%)
104 data subcarriers, 128-point (I)FFT, 8 pilots
8% increase on PHY rate: 2TX: 130/156Mbps, 3-4TX: 195/234Mbps
3rd OFDM modulation for 40MHz (optional):
104 data subcarriers, 128-point (I)FFT, 8 pilots
Guard interval duration: 0.8s
117% increase on PHY rate: 2TX: 260/312Mbps, 3-4TX: 390/468Mbps
Jechoux,Patillon Mitsubishi/Motorola

10. 40MHz mode design choice Methodology: Proposition:
Choose to design single RF front-end architecture with on the fly reprogrammable filters able to address 20MHz and 40MHz
Derive compatible OFDM parameters
Proposition:
Preserve same number of poles (same frequency response in normalized frequency) band stop doubled at 40MHz
Reassign the center null carriers on the side ones to allow lower filter selectivity on the edges
20MHz channels
40MHz channel
Jechoux,Patillon Mitsubishi/Motorola

11. Multi-antenna scheme
Proposition: hybrid schemes relying on a combination of robust Space-Time Block Coding (STBC) and Spatial Division Multiplexing (SDM)
very simple transmitter implementation
very simple receiver implementations are possible as classical orthogonal designs are part of the proposed STBCs
e.g. design of low complexity ZF or MMSE equalizers
very good performance complexity tradeoff for robustness in asymmetric MIMO
Importance of configurations in which NTx ≠ NRx
NTx > NRx e.g. between AP and mobile handset (in DL)
NTx < NRx e.g. between MT and AP (UL), or if MT have upgraded multi-antenna capabilities compared to AP (infrastructure upgrade cost)
Exploit all available transmit diversity when NTx > NRx to improve Tx reliability
Construction: transmission of 1, 2 or 3 parallel streams using,
2, 3 or 4 transmit antennas
The number of receive antennas determines the maximum number of spatial streams that can be transmitted.
The capability of decoding 2 parallel data streams is mandatory
all the devices have to be able to decode all the modes where the number of spatial streams is lower or equal than the number of receive antennas in the device.
It is required for a device to exploit all its antennas in transmission even for optional modes.
2 or more receive antennas
With STBC or STBC/SDM, asymmetric antenna configurations can be supported
Jechoux,Patillon Mitsubishi/Motorola

12. 2 transmit antenna schemes proposed
Asymmetric Modes for a robust hybrid solution
2 transmit antenna schemes proposed
3 transmit antenna schemes proposed
4 transmit antenna schemes proposed
Jechoux,Patillon Mitsubishi/Motorola

13. Asymmetric MIMO motivation/illustration
2x23x2: 2.8dB5dB
Simulation parameters
20MHz bandwidth, 48 carriers
64QAM, CC 2/3 and 5/6
Packet size: 1000 bytes
Channel TGn D NLOS
MMSE MIMO detection, perfect CSI
2x24x2: 4.3dB7.5dB
3x34x3: 2dB5.4dB
Jechoux,Patillon Mitsubishi/Motorola

14. Frequency and spatial interleaver
2-step interleaving process
Interleaving prior to mapping
802.11a like frequency interleaving with new parameters suitable to both OFDM modulations (48 and 104 subcarriers)
Interleaving prior to space-time coding
based on the frequency interleaver parameters to ensure adjacent bits are transmitted on different streams
NSD : number of data subcarriers
Jechoux,Patillon Mitsubishi/Motorola

15. Mode: 2-TX 48 carriers 20MHz Mode: 2-TX 104 carriers 20MHz Month 2003
doc.: IEEE /xxxr0
288
384 8
3/4
256QAM 2
144Mbps
240 6
5/6
64QAM
120Mbps
216
108Mbps
192
2/3
96Mbps
144 4
16QAM
72Mbps 1
60Mbps
48Mbps
36Mbps 96
1/2
24Mbps 72
QPSK
18Mbps 48
12Mbps 24
BPSK
6Mbps
Data bits/ symbol (NDBPS)
Coded bits/ symbol (NCBPS)
Coded bits per subcarrier per stream (NBPSC)
Coding rate (R)
Modulation
Number of spatial streams (NS)
Data rate (Mbits/s)
Mode: 2-TX 48 carriers 20MHz
624
832 8
3/4
256QAM 2
156Mbps
520 6
5/6
64QAM
130Mbps
468
117Mbps
416
2/3
104Mbps
312 4
16QAM
78Mbps 1
65Mbps
52Mbps
39Mbps
208
1/2
26Mbps
156
QPSK
19.5Mbps
104
13Mbps 52
BPSK
6.5Mbps
Data bits/ symbol (NDBPS)
Coded bits/ symbol (NCBPS)
Coded bits per subcarrier per stream (NBPSC)
Coding rate (R)
Modulation
Number of spatial streams (NS)
Data rate (Mbits/s)
Mode: 2-TX 104 carriers 20MHz
Jechoux,Patillon Mitsubishi/Motorola
H.Bonneville, B.Jechoux, Mitsubishi ITE

16. Mode: 3/4-TX 48 carriers 20MHz
Month 2003
doc.: IEEE /xxxr0
Mode: 2-TX 104 carriers 40MHz
Mode: 3/4-TX 48 carriers 20MHz
Jechoux,Patillon Mitsubishi/Motorola
H.Bonneville, B.Jechoux, Mitsubishi ITE

17. Mode: 3/4-TX 104 carriers 20MHz
Month 2003
doc.: IEEE /xxxr0
Mode: 3/4-TX 104 carriers 20MHz
Mode: 3/4-TX 104 carriers 40MHz
Jechoux,Patillon Mitsubishi/Motorola
H.Bonneville, B.Jechoux, Mitsubishi ITE

18. Forward Error Correction scheme
Proposed FEC scheme:
Mandatory: all IEEE802.11a CC with additional 5/6 puncturing pattern
Introduction of an optional advanced coding scheme: parallel binary turbo code with mother rate 1/3 with 3G polynomials (rate ½, 2/3, ¾, 5/6 achieved with puncturing).
TCs are stable, well-understood technology yielding good performance with known IPR landscape
Implementation features and advantages:
Adaptable block sizes relying on segmentation: breaks padded sequence into 2048-bit segments plus at most one segment of length 512, 1024, or 1536 bits  yields simple construction of corresponding interleavers
Constituent encoders left unterminated: it helps preserving exact code rate. Negligible performance degradation; scrambling performed before padding insertion
“Parallel window” decoder architecture easily scaled to meet latency requirements:
For a 2048-bit information block implementation, 10ms per iteration possible on 2001 FPGA scales to 1.25ms per iteration on current ASIC (higher clock rate and smaller window size)
Interleavers parallelized to avoid memory contentions without performance penalty
Jechoux,Patillon Mitsubishi/Motorola

19. Gain of Turbo vs. Convolutional Codes
Average PER vs SNR comparison on channel D
Left: STBC 2x2, 64QAM, R=1/2, N=2048 bits, no tail, rand. intlv.
Right: SDM 2x2, 64QAM, R=3/4, N=2048 bits, no tail, rand. intlv.
Conclusions:
The gain remains between 2-3 dB on TGN-D channel even with severe puncturing
Jechoux,Patillon Mitsubishi/Motorola

20. Preamble Design nSTS : time synchronization, frequency offset, AGC
Code overlay time domain sequence design on finite alphabet {0,±1, ±j} leads to simple cross correlator implementation
nLTS : synchronization refinement, channel estimation
Orthogonal design instead of cyclic shift approach: Walsh-Hadamard weighting leads to greater accuracy for CIR estimation
Jechoux,Patillon Mitsubishi/Motorola

21. Short Training Sequence Preamble
Time domain design using alphabet {0,±1, ±j}
nSTS choice criteria: Spectral & auto/cross-correlation properties
Frame definition: nSTS are weighted by ±1, nSTS
Exploitation: time synchronization, Automatic Gain Control, freq offset
Jechoux,Patillon Mitsubishi/Motorola

22. Performances: Time Synchronization
Typical time synchronization performances for 2x2 antennas case
Typical time synchronization performances for 4x4 antennas case
Time synchronization very reliable for 4x4 antennas case even for very low SNR (< 0dB)
Important for hybrid 4x4 antennas modes, since they work for very low SNR
Good reliability even for channel with large delay spread (TGe)
Time synchronization reliable for 2x2 antennas case
Jechoux,Patillon Mitsubishi/Motorola

23. Long Training Sequence preamble
Focus on a orthogonal design allowing
easier tradeoff between quality/complexity for CSI estimation: frequency domain only estimation is possible
Inclusion of time confinement constraint into the estimator possible yielding a more robust estimator avoiding the important noise enhancement using ZF approaches with Cyclic Shift based methods
Definition in frequency domain from alphabet {0, ±1}
LTS over 56 subcarriers to further improve the accuracy of the channel estimator using time confinement constraint
LTS(#-28…#+28) = {-1, 1, -1, 1, 1, 1, 1, -1, -1, 1, 1, 1, -1, 1, 1, -1, -1, -1, -1, 1, 1, -1, 1, 1, -1, 1, -1, -1, 0, -1, -1, -1, 1, -1, 1, -1, -1, -1, 1, 1, 1, 1, -1, -1, 1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, 1, -1}
Jechoux,Patillon Mitsubishi/Motorola

24. Link quality metric feedback for efficient link adaptation
Accurate PER prediction tools are available:
E.g. Shannon capacity at RX output, exp-ESM effective SNR
yields several dBs gain w.r.t. SNR or ACK-based link adaptation
Observation: only the RX can predict PER accurately (knowledge of processing, interference)
Proposal:
Feedback current link quality metric
1 dedicated PDU for initial calibration so that feedback can be mapped on PER in multiple vendor environment
Jechoux,Patillon Mitsubishi/Motorola

25. Performance illustration for TGnD channel (CC67)
Performance improvements for 2x2  2x4 and 4x2  4x4 antennas
35dB
120 / SDM
(fluor. Eff.)
5dB
12 / STBC
18dB
48 / STBC
28dB
96 / SDM
SNR for PER=10-1
Mode (Mbps) / STC
7dB
12 / SDM-STBC
17dB
48 / SDM-STBC
25.5dB
96 / SDM-STBC
30dB
120 / SDM-STBC
SNR for PER=10-1
Mode (Mbps) / STC
2x2
4x2
2x4
4x4
2dB
12 / STBC
14.5dB
48 / STBC
20dB
96 / SDM
24dB
120 / SDM
SNR for PER=10-1
Mode (Mbps) / STC
29dB
180 / SDM-STBC
(Flour. Eff.)
19dB
96 / SDM-STBC
23dB
120/ SDM-STBC
SNR for PER=10-1
Mode (Mbps) / STC
Jechoux,Patillon Mitsubishi/Motorola

26. Simulation results - TGnD
4RX antennas: Full Diversity gain for all streams: 120 Mbps lowers SNR ~ 35dB  25.5dB  23dB
XXX  36dB  29dB
180 (effect)
180
5dB  4.5dB  3.5dB 12
18dB  14dB  11dB 48
27.5dB  21dB  19dB 96
35dB  25.5dB  23dB
120
SNR for PER=10-1
Mode/Mbps
Assymetric modes: #TX antennas < #RX antennas vs #RX antennas < #TX antennas
# TX antennas
<
# RX antennas
 Update MT
# TX antennas
>
# RX antennas
 Update AP
24dB
120
2dB 12
14.5dB 48
20dB 96
SNR for PER=10-1
Mode/Mbps
30dB
120
7dB 12
17dB 48
25.5dB 96
SNR for PER=10-1
Mode/Mbps
Jechoux,Patillon Mitsubishi/Motorola

27. Limited outdoor environment: Hotspot support
Benefit of 20MHz 128 carriers mode using a 32 samples cyclic prefix:
8% overall rate increase
designed to cope with larger channels for more efficient outdoor environment operations
Illustration for channel F: no error floor in performance for higher rates modes
Jechoux,Patillon Mitsubishi/Motorola

28. Simulation results – Offset compensation
No significant impact at 10% PER in channel E (NLOS)
0.0974
0.0617
0.0963
180Mbps
3x3 ~0
12Mbps
4x4
0.0001
48Mbps
0.0019
0.0016
96Mbps
0.0022
0.0021
120Mbps
0.0029
0.0024
0.0023
0.0002
0.0050
0.0045
0.0043
0.0298
0.0183
0.0297
2x2
0.0042
0.0037
0.0039
0.0018
0.0003
PER
carrier offset =+40ppm
carrier offset = 0ppm
carrier offset = -40ppm
Data rate (Mbits/s)
Antenna configuration
Impact of carrier frequency offset and symbol clock offset at SNR=50dB in channel E (LOS):
Small degradation of the PER performance
High data rate modes are more impacted:
PER (+40ppm)=112/100xPER
PER (+40ppm)=163/100xPER
High data rate modes are less impacted if spatial diversity:
3x3: PER (+40ppm)=158/100xPER
4x4: PER (+40ppm)=121/100xPER
Jechoux,Patillon Mitsubishi/Motorola

29. MAC Description Month 2003 doc.: IEEE 802.11-03/xxxr0 summary deck
Jechoux,Patillon Mitsubishi/Motorola
H.Bonneville, B.Jechoux, Mitsubishi ITE

30. ECCF overview ECCF: “Extended Centralised Coordination Function”
Functions are distributed over 4 sub-layers
802.2 LLC
802.2 LLC
ECCF MAC
Legacy MAC
Packet Sequence Number Assignments
MAC Header Compression
LLCCS
Sequence Number Assignments
Fragmentation
Encryption
MDU Header + CRC
Segment Sequence Number Assignments
Segmentation/Re-Assembly
SAR
MIS
Error and Flow Control
MLS
Encryption
MPDU Header
Signalling Insertion
PHY
PHY
Jechoux,Patillon Mitsubishi/Motorola

31. Frame structure and timing
MAC Super Frame & Beacon kept for compatibility.
A part of the Contention Free Period (CFP) or some Controlled Access Periods (CAP) are used to inset ECCF periods.
Resource scheduling performed on a per MTF basis (fixed duration: e.g.2 ms).
Variable duration Time Intervals (TI) dynamically allocated to STAs within an MTF.
ECCF
PCF/HCCA
DCF/EDCA
CFP CP
Beacons
MTF
Beacon
Information CF
Parameter Set
MAC Super Frame
CAP
Jechoux,Patillon Mitsubishi/Motorola

32. Example of .11e and ECCF peaceful coexistence
ECCF scheme is flexible enough to easily handle backward compatibility
Question: how to have clean coexistence of .11e QoS STA and .11n ECCF STA
Practical case: mixed environment, .11n stations + .11e VoIP terminals
Solution:
the RRM reserves time for legacy stations every 10 ms using insertion into CAP method
granularity of ECCF reservation (MTF) is 2ms
several ECCF MTF can be embedded in superframe
VoIP .11e stations are able to operate
CAP ECCF
ECCF
DCF/EDCA CP
Beacons
MTF
Beacon
Information CF
Parameter Set
MAC Super Frame …
Jechoux,Patillon Mitsubishi/Motorola

33. Frame structure and timing (cont.)
MTF composition defined in a specific MPDU = PGPM
Variable duration TI constituted of one MPDU = data unit exchanged with the PHY layer as in legacy (i.e. one PLCP preamble per MPDU)
MPDU contains two parts: signalling and data
contents defined by the emitter (source STA)
data and signalling can be intended for one or more destination STAs
Multiple MCS / Multiple flows / Multiple destinations aggregation
Possible long PHY bursts (up to 1ms)
PGPM
MTF
Data
TI#0
TI#1
TI#2
TI#3
TI#4
MPDU
Jechoux,Patillon Mitsubishi/Motorola

34. MTF structure (detailed)
Each resource is described at the beginning of an MTF in the PGPM
MPDU signalling part (variable length):
Includes resource requests, Error Control signalling,...
Includes description of data blocks (if any)
MTF structure example
MPDU
STA#2
STA#1
PGPM
MPDU
PGPM
Header
HSCS
TID STA#1
->STA#2
TID STA#4
->RRM,STA#3
Signalling
Signalling
MPDU
Header
HSCS
Data
DPD
STA#2
Data Block
to STA#2
MPDU
Header RR
->RRM
Signalling FB
->STA#3
HSCS
Sent by
RRM
STA#4
All
RRM, STA#3
(TI #0)
(TI #1)
(TI #2)
Jechoux,Patillon Mitsubishi/Motorola

35. Aggregation
An MPDU may aggregate several data blocks sent by a station
SDU
MPEGflow
VOIP flow
TCP flow
SAR
MPDU
Header
HSCS
Aggregated MPDU, up to 1ms
Signalling
Data Block #1
Data Block #2
Data Block #3
LLC
Fixed size segments (2 possible lengths)
CRC
MIS-PDU
HDR
...
LLCCS
(*) LLC packet sequence number
(**) Segment sequence numbers
...
MPDU description part has a dedicated protection (HSCS)
Possible Multiple MCS / Multiple flows / Multiple destinations
In particular, description part can use a robust PHY mode
Sequence numbers: 2 levels
(*) at LLC level (LLCCS-PDU), and (**) at segment level (MIS-PDU)
SAR is easy to implement
Jechoux,Patillon Mitsubishi/Motorola

36. Resource allocation scheme
MTF (2ms)
RG-STA A RR
CTI location
PGPM
CTI Location
STA A
STA B
RRM
RG-STA B
ECCF period (within CAP or CFP)
CTI
CTI ACK
Resource request (RR) and resource grant (RG)
Data
RR via in band signalling
RR via contention
Signalling TIs (Resource announcement + Contention) RG
Successful contention ACK
Jechoux,Patillon Mitsubishi/Motorola

37. Enhanced ACK & Flow control
Performed on a per-flow basis (src STA, dst STA, priority)
Operated independently from the aggregation
Feedback sent upon request from source or triggered by receiver
May be sent in-band or out-band
May be cumulative when no errors (compact) or selective with bit map bloc otherwise (accurate)
Flow control
Negotiated minimum window size (throughput guaranty)
or signaled
Jechoux,Patillon Mitsubishi/Motorola

38. Enhanced ACK Aggregated MPDUs (PHY bursts)
SID
Seq Nb -> N
Priority
Flags
Cumulative Ack
Seq Nb -> M
MISPU
Bit Map (32 bits)
Selective Ack
SID1, Pr1
SID2 , Pr3
SIE
Data
In band feedback message
SID: Short station IDentifier
Dst STA (SID 2)
Src STA
Feedback message
Dst STA (SID1)
Preamble + MAC Header
LLC
CRC
MIS-PDU
HDR
SDU N
SDU M
SDU M -1
Jechoux,Patillon Mitsubishi/Motorola

39. High range dedicated .11n Beacon
Goal: Enable materialisation of new PHY mode range
Proposal: Introduction of a dedicated beacon
Transmitted with MIMO 2Tx, 1 flow, BPSK STBC CC1/2 (6 Mbps)
Include all legacy system Information
Add ECCF specific elements
CFP CP
MAC Super Frame
ECCF
PCF/HCCA
DCF/EDCA/ECCF
CAP(ECCF)
Legacy Beacon
N- Beacon
CF-Poll
Green Field Case
N Beacon only is transmitted
Mixed Mode
Dual Beacon, Legacy kept as is
an N Beacon immediately after legacy one
Valid for both Mixed Mode and Green Field
Gain of 6db => ~50% Range increase for .11n stations
BSS overlapping avoided by DFS as per h
Jechoux,Patillon Mitsubishi/Motorola

40. System Performance Month 2003 doc.: IEEE 802.11-03/xxxr0 summary deck
Jechoux,Patillon Mitsubishi/Motorola
H.Bonneville, B.Jechoux, Mitsubishi ITE

41. ECCF Robustness MAC Efficiency vs PER (Scenario I bis, IV, VI bis)
Month 2003
doc.: IEEE /xxxr0
ECCF Robustness
MAC Efficiency vs PER (Scenario I bis, IV, VI bis)
Slight impact of the PER on MAC efficiency
retransmission with low signalling SR-ARQ
MAC efficiency:
Robust vs PER
> 60% even for harsh conditions (*)
High performance even in bad radio conditions
Results valid whatever the application packet size (c.f.segmentation)
(*) PER for 134 bytes packets, 1E-1 equivalent to 9.5E-1 for 4000 bytes or 6.9E-1 for 1500 bytes packets
Jechoux,Patillon Mitsubishi/Motorola
H.Bonneville, B.Jechoux, Mitsubishi ITE

42. ECCF Scalability
Goodput at MAC SAP vs PHY data rate (point-to-point scenario)
linear variation
MAC efficiency:
Constant vs PHY rate
High level: [76% ; 86%]
Fully scalable for high bit rates
Results valid whatever the application packet size (c.f.segmentation)
Jechoux,Patillon Mitsubishi/Motorola

43. Mixed traffic handling
Capacity usage at MAC-SAP vs. Number of VoIP sessions
1 TCP data flow transmitted using MIMO 3x3_64QAM2/3 (Ns=3) [144Mbit/s]
VoIP: 120-byte packets emitted every 10 ms (2x96kbit/s)
n VoIP sessions, using either 2x2_64QAM2/3 (Ns=1) [48Mbit/s] or 2x2_16QAM1/2 (Ns=1) [24 Mbit/s]
MAC Efficiency between 78% and 55%
30 VoIP sessions + at least 65 Mbit/s of TCP traffic
Jechoux,Patillon Mitsubishi/Motorola

44. Delay performances IEEE TGn Usage models : Scenario I (Home)
Traffic classification based on priority level (VoIP > TCP)
Delay comparison for different error rate [cdf(d>D)]
Strong QoS constraints of VoIP reached:
with a simple centralised scheduling
an efficient ACK
Max delay below 20 ms for QoS traffic
Jechoux,Patillon Mitsubishi/Motorola

45. Simulation results for Scenarios 1
all data flow transmitted
using MIMO 3x2 64QAM
3/4 (Ns=2) or 2x2 16QAM
3/4 (Ns=1)
Modified scenario 1bis:
Infinite TCP sources +
PHY modes ( Mbit/s)
Metrics
Performance
Average
PHY rate
Non-QoS
goodput
QoS
(171%)
Satisfied
QoS flows
(100%)
139 Mbps CC
Targets
76 % MAC Efficiency 17
53 Mpbs
53 Mbps
Scenario 1bis
All QoS requirements can be achieved with 106 Mbit/s at PHY
76% MAC efficiency
106 Mbit/s available at MAC-SAP (139 Mbit/s avg at PHY)
Jechoux,Patillon Mitsubishi/Motorola

46. Simulation results for Scenario 4
Metrics
Performance
Average
PHY rate
Non-QoS
goodput
QoS
(100%)
Satisfied
QoS flows
(27%)
178 Mbps CC
Targets
73 % MAC Efficiency 18
121 Mpbs
9 Mbps
Scenario 4
Scenario 4:
PHY modes
Mbit/s
73% MAC efficiency
130 Mbit/s available at MAC-SAP (178 Mbit/s avg at PHY)
Jechoux,Patillon Mitsubishi/Motorola

47. Simulation results for Scenarios 6
Metrics
Performance
Average
PHY rate
Non-QoS
goodput
QoS
Satisfied
QoS flows
(100%)
155 Mbps CC
Targets
67 % MAC Efficiency 39
45 Mpbs
(292%)
58 Mbps
Scenario 6 bis
Scenario 6:
all data flow transmitted
using MIMO 3x3
64QAM2/3 (Ns=2)
or 2x2 64QAM5/6 (Ns=1).
Modified scenario 6bis:
Infinite TCP sources +
PHY modes ( Mbit/s)
QoS requirements can be achieved with 92 Mbit/s at PHY
67% MAC efficiency
103 Mbit/s available at MAC-SAP (155 Mbit/s avg at PHY)
Jechoux,Patillon Mitsubishi/Motorola

48. Results conclusion QoS requirements supported (throughput and delay)
Month 2003
doc.: IEEE /xxxr0
Results conclusion
QoS requirements supported (throughput and delay)
In all scenarios
High level MAC efficiency
Above 65 % in all scenarios
Efficient with QoS flows as non QoS flows
Very good scalability
Constant efficiency versus PHY rate
Backward compatibility
Flexibility ensured, without context-dependent tuning
Full support of all mandatory 11n simulations scenarios with a 120 Mbps PHY layer
Jechoux,Patillon Mitsubishi/Motorola
H.Bonneville, B.Jechoux, Mitsubishi ITE

49. Differentiators Resource allocation mechanism is highly dynamic
QoS provided without use of traffic profiles (TSPECS)
Enhanced transparency and predictability through broadcast grouped resource announcement
yields clean low power implementation and low overhead
Inherent clean split between legacy and .11n devices at MAC level
no need for mixed-modes transmission mode definition
High Efficiency independent of application packet size through segmentation
Robustness to error through retransmission mechanism on segmented packets
.11n specific beacon enables materialization of new PHY mode range prediction
Build in support for asymmetric TX/RX antenna configurations to accommodate various terminal sizes (PDA/Phone) offering a scalable and evolutionary solution
New preamble definition: allowing easier tradeoff between quality/complexity for CSI estimation avoiding the important noise enhancement using ZF approaches
Open-loop link quality feedback for easier and better link adaptation
Jechoux,Patillon Mitsubishi/Motorola