1. A possible path to convergence
August 2004
IEEE MAC Elements for n
A possible path to convergence
Jim Allen and Dr. James P.K. Gilb
(Appairent Technologies)

2. August 2004
Goals of n
The primary purposes of .11n (from various sources including Wi-Fi document n) are:
to get higher throughput
more range
more robustness
uniform coverage
broaden the class of applications (like “Phase II” video hotspots)
backwards compatibility mode with .11
Get to market faster…
Jim Allen and Dr. James P.K. Gilb
(Appairent Technologies)

3. August 2004
MAC
The MAC is experiencing asymptotic throughput limit as a function of data rate.
QoS priority method permits “priority cheating” and collapses back into access issues
CAP still allows the network to be affected by network loading. Needs Access denial capability
Jim Allen and Dr. James P.K. Gilb
(Appairent Technologies)

4. August 2004
MAC
Experiences asymptotic throughput at a much higher data rate and allows ways to reduce effect (like the CAP is optional and there are ways to send multiple unique packets in one CTA)
Once a Time slot is assigned, inefficient contention for it stops
Uses access denial to prevent QoS reduction
Jim Allen and Dr. James P.K. Gilb
(Appairent Technologies)

5. As a result, we see: We also see: Market segmentation:
August 2004
As a result, we see:
Proprietary .11 extensions starting to appear
…that work for small networks but not entertainment systems (e.g. synchronized video and speakers)
Promises by .11 members to produce “.11n” products before the standard is done
We also see:
/3b is gaining traction
…and can technically move easily in to IP services.
Market segmentation:
PC entertainment and CE entertainment will converge
causing unnecessary choices by OEMs
Jim Allen and Dr. James P.K. Gilb
(Appairent Technologies)

6. August 2004
Demo Example
The following slide shows the old January 2004 CES demo as an example of capability
Demo shows maturity of:
video distribution
audio distribution
video and audio Synced’
audio repurposed from several sources
Next demo will show latency capabilities using live video and bidirectional audio
Jim Allen and Dr. James P.K. Gilb
(Appairent Technologies)

7. Synchronized Audio and Video
August 2004
Server
PNC
DEV1
Player
Stream 1
Subwoofer
Center Speaker
Stream 3
Front Right Speaker
Front Left Speaker
Video Stream 2
TRES-DEV3
Stream 2
DEV2
Video Stream 1
AirPlayer-3
Front Right Speaker
Speaker
Front Left Speaker
Rear Right Speaker
Rear Left Speaker
Synchronized Audio and Video
Mobile (on a cart)
Jim Allen and Dr. James P.K. Gilb
(Appairent Technologies)

8. August 2004
Technology Realities
already has excellent AP technology that is already being adapted to designs
The Mesh requirements outline MAC functions already in Both groups have mesh teams
Radio measurement and other .11 groups will add functionality that is also of interest to
has coexistence capabilities that make it a good partner for (like TPC and .11 channel plan)
Jim Allen and Dr. James P.K. Gilb
(Appairent Technologies)

9. Channel Time Allocation Period
August 2004
15.3 Superframe Structure
Superframe #m-1
Superframe #m
Superframe #m+1
Beacon #m
Contention
Access
Period
Channel Time Allocation Period
MCTA 1
MCTA 2
CTA 1
CTA 2
CTA n-1
CTA n
Time-slotted superframe structure consists of 3 sections:
Beacon:
Transmits control information to the entire piconet, allocates time resources and provides time synchronization
Optional CAP (CSMA/CA):
Used for authentication/association, CTA requests and other commands
PNC may replace the CAP with MCTAs using slotted Aloha access (with greatly reduced efficiency)
Channel time allocation period (CTAP) made of:
Unidirectional channel time allocations (CTAs) assigned by the PNC
Optional management CTAs (MCTAs) in lieu of the CAP for command frames
Jim Allen and Dr. James P.K. Gilb
(Appairent Technologies)

10. August 2004
Technology Realities
has very efficient (>80%) TDMA based MAC capabilities but is probably the right asynchronous approach
had advance power save and ad hoc capabilities
and can use the same RF sections. Dual mode devices are on product roadmaps
and both use 128 bit AES CCM
Jim Allen and Dr. James P.K. Gilb
(Appairent Technologies)

11. Technology Realities 15.3 Rate Roadmap
August 2004
Technology Realities
15.3 Rate Roadmap
is a 55 Mbps standard TODAY.
Currently available methods can increase rate to 167 Mbps at 2.4 GHz
a sets the expectations at >110 Mbps (data rate)
UWB activities already forcing the MAC to 480 Mbps chips by mid 2005.
UWB customers expect 1 Gbps by start of 2006.
Jim Allen and Dr. James P.K. Gilb
(Appairent Technologies)

12. August 2004
The Opportunity
If we can get over the political hurtles and NIH (Not Invented Here) syndromes:
We have an opportunity to converge technologies
Simplifies OEM choices
Improve performance for all
Take advantage of the technologies developed in both groups
Get to market faster
Jim Allen and Dr. James P.K. Gilb
(Appairent Technologies)

13. Joint Project Approach
August 2004
Joint Project Approach
Fast process
Standard + Standard = Standard
Specify correct link points
Specify correct interface
Spend most of .11n resources on PHY improvements
The 15.3 MAC is already operational so testing can be done as the draft is written.
This can speed the .11n total process
There may be an opportunity for Wi-Fi to take over WiMedia’s role for 15.3 allowing it to control the convergence message
Jim Allen and Dr. James P.K. Gilb
(Appairent Technologies)

14. How to support this proposal
August 2004
How to support this proposal
This is a partial proposal (per 11-03/0665)
It can’t be voted on by itself so the analysis for the full proposal will be done after a merger
Consider this a solicitation for Merger
A judgment is needed as to whether this is within the scope of the PAR
Contact the authors
Jim Allen
James Gilb
Jim Allen and Dr. James P.K. Gilb
(Appairent Technologies)