1. Thoughts on VHT Date: 2007-05-15 Authors: May 2007 April 2007
doc.: IEEE /0570r0
May 2007
Thoughts on VHT
Date:
Authors:
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Eldad Perahia, Intel Corporation
Eldad Perahia, Intel Corporation

2. Abstract Some thoughts on direction and requirements for VHT May 2007
April 2007
doc.: IEEE /0570r0
May 2007
Abstract
Some thoughts on direction and requirements for VHT
Eldad Perahia, Intel Corporation
Eldad Perahia, Intel Corporation

3. History of HT First high data rate presentation in WNG in Jan 2002
April 2007
doc.: IEEE /0570r0
May 2007
History of HT
First high data rate presentation in WNG in Jan 2002
This was followed by numerous presentations on:
PHY technology, including MIMO prototype
MAC efficiency
Markets and applications
The first HTSG meeting was in Sept. 2002
The first TGn meeting was in Sept. 2003
HTSG lasted a year even with prep work done in WNG
The process for forming VHT skipped the step of technology and market presentations in WNG
This will need to be incorporated in VHT work
We need to investigate markets and usage models
We need to develop technical requirements from usage models
Eldad Perahia, Intel Corporation
Eldad Perahia, Intel Corporation

4. Requirements of VHT Create a focused PAR and five criteria
April 2007
doc.: IEEE /0570r0
May 2007
Requirements of VHT
Create a focused PAR and five criteria
To borrow from HT/TGn
Very high throughput
Spectral efficiency
Range/Robustness/Coverage
Interoperability/Coexistence
Any others?
Eldad Perahia, Intel Corporation
Eldad Perahia, Intel Corporation

5. Very high throughput May 2007
April 2007
doc.: IEEE /0570r0
May 2007
Very high throughput
What increase in PHY rate are we looking for?
802.11: 2 Mbps in 25 MHz
11b: 11 Mbps in 25 MHz
11a/g: 54 Mbps in 20/25 MHz
11n: 300 Mbps in 20/25 MHz, 600 Mbps in 40 MHz
VHT
Another factor of 5?
Bandwidth
TGn increased the channel from 20 to 40 MHz
Should VHT further increase channel BW? If so, how much?
Do we use existing bands? Or new bands?
What is the proper metric?
The requirement for TGn was minimum of 100 Mbps throughput at MAC SAP
Should we use throughput at MAC SAP?
Network capacity?
Will the TGn MAC support higher throughput/efficiency with higher PHY data rates?
Will any modifications of the TGn MAC improve efficiency at higher PHY data rates, or do we need a new MAC?
Eldad Perahia, Intel Corporation
Eldad Perahia, Intel Corporation

6. Spectral efficiency Evolutionary ways to increase spectral efficiency:
April 2007
doc.: IEEE /0570r0
May 2007
Spectral efficiency
Evolutionary ways to increase spectral efficiency:
More spatial steams
TGn has 4 spatial streams
Increase to 6 or more?
Will the channel support more than 4 spatial streams?
What is the antenna correlation with that many antennas on a platform?
What platforms are we talking about?
Higher order modulation and higher code rate
Incremental increase in spectral efficiency by going to 256-QAM
TGn has rate 5/6 code
Increase to 7/8 or 1?
Will Tx or Rx HW support this with impairments based on reasonable cost/complexity device?
Eldad Perahia, Intel Corporation
Eldad Perahia, Intel Corporation

7. Range/Robustness/Coverage
April 2007
doc.: IEEE /0570r0
May 2007
Range/Robustness/Coverage
We are LAN, we should strive to increase the data rate while maintaining coverage similar to TGn
If we use higher frequencies, like millimeter wave, how do we maintain range comparable to current dot11 devices?
Eldad Perahia, Intel Corporation
Eldad Perahia, Intel Corporation

8. Interoperability/Coexistence
April 2007
doc.: IEEE /0570r0
May 2007
Interoperability/Coexistence
Coexistence with legacy devices turned out to be the most difficult topic in TGn
Regarding coexistence in 5 GHz, in TGn arguments were made that there wasn’t much deployment of 11a devices in 5 GHz
There will be large deployment of 11n devices in 5 GHz, similar arguments regarding backward compatibility can not be made
Do we allow VHT in 2.4 GHz?
Do we allow VHT in 5 GHz?
If we use new spectrum, are there non devices in the band and what are coexistence issues with these devices?
Eldad Perahia, Intel Corporation
Eldad Perahia, Intel Corporation

9. Relationship with IMT-Advanced
April 2007
doc.: IEEE /0570r0
May 2007
Relationship with IMT-Advanced
VHT should be independent of IMT-Advanced
We should develop a PAR and 5-Critera that are based on technology and market requirements
We do not want changes in requirements and timeline in IMT-Advanced to force PAR changes
Eldad Perahia, Intel Corporation
Eldad Perahia, Intel Corporation

10. Relationship with Video Transport Stream Study Group
April 2007
doc.: IEEE /0570r0
May 2007
Relationship with Video Transport Stream Study Group
Low compression, high rate video streaming is an obvious application which will drive requirements for both VHT and VTS
We need to avoid overlap with VTS by maintaining good coordination between the two study groups
Eldad Perahia, Intel Corporation
Eldad Perahia, Intel Corporation

11. Summary PAR must be focused for successful TG
April 2007
doc.: IEEE /0570r0
May 2007
Summary
PAR must be focused for successful TG
In order to achieve that, we need due diligence on markets, applications, and technology
We need to have a good idea of whether VHT will be an evolutionary or revolutionary change to
Eldad Perahia, Intel Corporation
Eldad Perahia, Intel Corporation