Thursday, April 30, 2009

Can 802.11 cut the HD TV cords?

802.11/WiFi for HDTV

For those of us in the know, 802.11 is the de facto wireless standard for computing devices that comes with all wireless PC/laptop and is increasingly available with mobile handsets and gaming console.

So the logical question is can 802.11 become the de facto wireless standard for all electronic devices. Say, instead of wiring up my new HDTV with all the players and other devices, would something like 802.11 help cut the cords?

This is an issue that a lot of industry players are grappling with and the latest verdict, for whatever it is worth, is yes according to this analyst report "802.11n Wi-Fi Technology is the Spoiler at the Wireless HD Video Party; Will Dominate ("

Reality Check

Instead of arguing over the technical details, we conducted an analysis on how 802.11n will perform in typical home scenarios. Think of it as simulations on how 802.11n will work in a perfect environment - so your performance at home will only be worse...


It turns out that working out the specific variable/assumptions are the most tricky part. So, this is what we came up with. We want a home environment where there are different type of wireless traffics: some web surfing, some VoIP chatter, some TV watching, and some Blu-ray video watching.

We also looked into the distances amongst all the devices because interference is a very real issue with 802.11. As things are further apart, there is less inference and vice versa.

So, here are the variables that we tried in our simulations.


Blu-ray video
Media center (MC) - provides Blu-ray and HD TV to, up to, two (2) TV's
Web session
VoIP call
Access Point (AP) - support the web and VoIP sessions


Short - 3m/10ft
Medium - 10m/30ft
Long - 15m/50ft


Without being exhaustive, scenarios range from:

Most “forgiving”: 1 MC + 1 HDTV + 1AP + 1 VoIP + 1 Web at long distance (15m/50ft)


Least “forgiving”: 1 MC + 1 Blu-Ray + 1 Blu-Ray+ 1AP + 1 VoIP + 1 Web at short distance (3m/10ft)


The performance threshold that we used was less than 200msec delay. If it is more than that, it becomes noticeable to human perception.

The long and short of it is that 802.11n only works within the acceptable range in the case of one HDTV far away from other devices, i.e. the most "forgiving" scenario. On top of it, all the other users such as web surfing and VoIP would have to accept significant performance hit.


I would love to hear your experiences using 802.11 in a mixed-media environment with multiple users. Maybe I am missing something here.


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