1. Joint Proposal PHY Overview
November 2005
doc.: IEEE /xxxr0
November 2005
Joint Proposal PHY Overview
Date:
Authors:
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Mujtaba (Agere), Petranovich (Conexant) et. al.
Mujtaba (Agere), Petranovich (Conexant), Fischer (Broadcom), Stephens (Intel) et. al.

2. November 2005
Mujtaba (Agere), Petranovich (Conexant) et. al.

3. November 2005
Mujtaba (Agere), Petranovich (Conexant) et. al.

4. November 2005
Mujtaba (Agere), Petranovich (Conexant) et. al.

5. November 2005
Mujtaba (Agere), Petranovich (Conexant) et. al.

6. November 2005
Mujtaba (Agere), Petranovich (Conexant) et. al.

7. November 2005
Mujtaba (Agere), Petranovich (Conexant) et. al.

8. November 2005
Mujtaba (Agere), Petranovich (Conexant) et. al.

9. November 2005
Abstract
This document provides an overview of the joint proposal PHY, which is under development by the Joint Proposal group of TGn Sync, WWiSE, and Mitmot.
Mujtaba (Agere), Petranovich (Conexant) et. al.

10. November 2005
PHY Overview
Mujtaba (Agere), Petranovich (Conexant) et. al.

11. JP “decision making pipeline”
November 2005
JP “decision making pipeline”
Item under discussion
“Item agreed upon”
Motion
passes
Motion:
Draft text
put up for
ballot
Item brought
forth for
consideration
Presentations,
discussions, &
strawpolls
Draft text
included
in JP spec
Motion fails (i.e. less than 75% support)
Mujtaba (Agere), Petranovich (Conexant) et. al.

12. Recap of Architecture Encoder Puncturer Parser Interleaver QAM Mapper
November 2005
Recap of Architecture
Encoder
Puncturer
Parser
Interleaver
QAM
Mapper
Antenna
Mapper
iFFT
Window
& GI RF
Pilot
Preamble
Agreed upon
Under discussion
Mujtaba (Agere), Petranovich (Conexant) et. al.

13. Scalable PHY Architecture
November 2005
Scalable PHY Architecture
Mandatory
Optional
Robustness Enhancement
Open Loop SDM
Closed Loop Tx BF
Robustness Enhancement
Conv. Coding
LDPC
RX Assisted Rate Control
Throughput
Enhancement
2 Spatial Streams
4 Spatial Streams
Throughput
Enhancement
20 MHz
40 MHz
150 Mbps
 600 Mbps
Mujtaba (Agere), Petranovich (Conexant) et. al.

14. JP PHY Key Parameters November 2005 Parameter JP PHY Spatial Streams
1 to 4
FEC (BCC)
R=1/2, K=7
Generator polynomial (1338, 1718)
Puncturer: 2/3, 3/4, and 5/6
Number of Encoders TBD (1 or 2)
Parser
TBD (Group parser or Bit Parser or Hybrid)
Interleaver
Block based
One for each spatial stream
Spatial streams separated by frequency rotation
QAM Modes
BPSK, QPSK, 16-QAM, 64-QAM
256-QAM TBD
Antenna mapper
STBC, beam steering TBD
iFFT
20 MHz: 56 tones (52 data tones + 4 pilots)
40 MHz: 114 tones (108 data tones + 6 pilots)
Mujtaba (Agere), Petranovich (Conexant) et. al.

15. JP PHY Key Parameters November 2005 Parameter JP PHY GI 800ns
400ns TBD
Signal Bandwidth
20MHz, 40 MHz
Long MIMO Preamble
Long mixed mode preamble
Legacy compatibility: 100% interoperable
Supports per tone channel estimation
Supports frequency smoothing & interpolation
Compatible with beam forming
Short MIMO Preamble
TBD (green field or mixed mode)
HT-SIG modulation
TBD
Scrambler Init
MCS Set
Symmetric MCS sets:
defined from BPSK to 64-QAM
Asymmetric MCS sets (primarily for beam forming)
Mujtaba (Agere), Petranovich (Conexant) et. al.

16. JP PHY Key Parameters November 2005 Parameter JP PHY Pilot Tones
20 MHz
4 pilot tones
40 MHz
6 pilot tones
Advanced Codec
Low Density Parity Check codes are currently being developed
Code structure has been defined
Specific codes currently being verified
Final selection expected this week
Sounding Packet Format
Format is TBD (staggered sounding or block structure)
Space-Time Block Codes
Codes defined:
2 x 1
3 x 2
4 x 2
4 x 3
Optional or mandatory TBD
Mujtaba (Agere), Petranovich (Conexant) et. al.

17. Long Mixed Mode Preamble
November 2005
Long Mixed Mode Preamble
Structure
Legacy portion maximum CDD delay ≤ 200 nsec for reliable legacy interoperability
High throughput CDD delay at least 200 nsec per antenna for improved performance
Mujtaba (Agere), Petranovich (Conexant) et. al.

18. Items currently under discussion
November 2005
Items currently under discussion
Number of encoders
Parser format
256 QAM
Beam steering
400ns GI
Short preamble
Asymmetric MCS
Mujtaba (Agere), Petranovich (Conexant) et. al.

19. Number of encoders Single encoder: Dual encoder:
November 2005
Number of encoders
Single encoder:
Lower implementation overhead
Difficult implementation at very high data rates
Dual encoder:
Perhaps higher implementation overhead
Not attractive for LDPC encoding
Alleviates implementation concerns at very high data rates
Under what conditions should the second encoder kick in?
Mujtaba (Agere), Petranovich (Conexant) et. al.

20. Parser format Two flavors: Bit wise: Group wise: Hybrid: Bit wise
November 2005
Parser format
Two flavors:
Bit wise
Group wise
Bit wise:
Better performance for symmetric modulations
However, does not support asymmetric modulations
Group wise:
Designed to support asymmetric modulations
However, performance slightly degraded for symmetric modulations
Hybrid:
Bit wise for symmetric & group wise for asymmetric
Complicates control?
Mujtaba (Agere), Petranovich (Conexant) et. al.

21. 256-QAM Requires very high EVM at Tx Requires very high SNR at Rx
November 2005
256-QAM
Requires very high EVM at Tx
Requires very high SNR at Rx
“Perhaps” feasible if system has adequate array and/or diversity gain:
For example, when used with beam steering
Mujtaba (Agere), Petranovich (Conexant) et. al.

22. Beam steering Format of sounding packet:
November 2005
Beam steering
Format of sounding packet:
Two flavors – staggered or block
Staggered – introduces a new preamble format, but preserves performance
Block – reuses the existing preamble format, but may experience power fluctuation
Feedback of channel estimates to the Tx:
Explicit
Implicit
Mujtaba (Agere), Petranovich (Conexant) et. al.

23. 400ns GI 400ns GI improves efficiency by reducing overhead
November 2005
400ns GI
400ns GI improves efficiency by reducing overhead
Useful for scenarios that are limited in delay spread
However, 400ns GI complicates the design of the channel select filter at the receiver
Reducing the temporal footprint of the filter may compromise it’s ability to reject adjacent channel energy
Frequency with which delay spread needs to be estimated is unclear
Mujtaba (Agere), Petranovich (Conexant) et. al.

24. Short Preamble Two flavors: Greenfield: Greenfield format
November 2005
Short Preamble
Two flavors:
Greenfield format
Short mixed mode preamble
Greenfield:
Shortest possible preamble
No legacy interoperability
Legacy interoperable
Shorter than the “Long Mixed Mode” preamble
Design is more difficult to optimize since constraints are higher
Mujtaba (Agere), Petranovich (Conexant) et. al.

25. November 2005
Asymmetric MCS
Increases “link rate” when eigen-channels are highly asymmetric in SNR
Can only be used if channel state information is available at the transmitter
However, increases system complexity, size of the MCS set, and burdens interoperability testing
Mujtaba (Agere), Petranovich (Conexant) et. al.

26. November 2005
Summary
Open items have pros and cons that place them in the “gray” area
Not a black and white decision!
Consensus will be reached via compromise rather than based on definitive technical data
Mujtaba (Agere), Petranovich (Conexant) et. al.