What's up with 802.11n?

[GGCO]

Last night my team mates and I were setting up the new controller's network, so we could connect to it. We noticed that the manual would only broadcast in 802.11n.

Two people (that's half of our programming cell on our team) don't have laptops with 802.11n adapters in them, and we were wondering if we can just switch the settings to broadcast in 802.11g/b/n?

Also, if you cannot broadcast on 802.11g, why did they choose 802.11n?? Not many people (at least that I know) use it.

[RyanN]

Not many people (at least that I know) use it.

I think that's the main reason... not much traffic. Plus, more bandwidth, faster transmission of data... just all sorts of good stuff.

[GGCO]

That might be it, but it seems so counter-intuitive. I would think that you should use the protocol that most team's computers would be compatible with.

So, do you think that it is possible to change the way it is broadcasting in?

[cabbagekid2]

If you don't have wireless n, what our team has done is connect it to the driver station through an ethernet cable to download the code. There is no need to have your laptop have wireless n. It's not much of an inconvenience to plug your computer to the driver station since both are usually near each other when testing your robot.

Not sure about the effects of changing it to g/h.

[GGCO]

Yeah, it really is not a problem but I would like to have the capabilities of connecting to the network remotely simply for convenience.

[Jon Stratis]

a, b, g, and now n are the various revisions of the IEEE 802.11 spec - basically, each new version is an upgrade over the previous one. All the letters in between there were lost in the shuffle - they didn't differentiate themselves enough to make ti worth while to put in consumer products.

That being said, N has been out for a while now - it was ratified in January '06, if memory serves. Prior to that, most major computer manufacturers and wireless router companies had what were called "draft n" cards available - basically, they were faster than G, but not guaranteed to be compatible with official N devices after the revision was ratified. Most routers and wireless cards have no problem connecting to b/g networks, and anything you've bought in the past year or so should have an n card in it.

n provides many benefits to end consumers (and FIRST robots) - longer range and increased data bandwidth being the two big ones. For FIRST, this means a single router has a much better chance of avoiding interference from robot frames and materials than a g router would. Further, providing teams with a g router now would be providing them with older technology, something that they would have to update in the next year or two as the availability of g routers became scarce (If you can even find them today).

So, hopefully that provides some insight into why FIRST probably decided on the router they did.

Now to answer your question...

It *should* be fine to set your router to utilize b/g/n instead of only n. Best case, you won't notice a difference. In the middle there might be some interference introduced. And worst case, it simply won't work and you'll have to set it back to n only. And in the least likely scenario, you'll set it to b/g/n and the world will explode. I doubt that will happen though

As for the gaming adapter (the part that sits on the robot) - make sure that is set up like FIRST instructs. You definitely don't want that acting anyway other than the way it should work at the competition, just to save the possible headache of your robot not working.

[GGCO]

Originally Posted by eagle33199

a, b, g, and now n are the various revisions of the IEEE 802.11 spec - basically, each new version is an upgrade over the previous one. All the letters in between there were lost in the shuffle - they didn't differentiate themselves enough to make ti worth while to put in consumer products.

That being said, N has been out for a while now - it was ratified in January '06, if memory serves. Prior to that, most major computer manufacturers and wireless router companies had what were called "draft n" cards available - basically, they were faster than G, but not guaranteed to be compatible with official N devices after the revision was ratified. Most routers and wireless cards have no problem connecting to b/g networks, and anything you've bought in the past year or so should have an n card in it.

n provides many benefits to end consumers (and FIRST robots) - longer range and increased data bandwidth being the two big ones. For FIRST, this means a single router has a much better chance of avoiding interference from robot frames and materials than a g router would. Further, providing teams with a g router now would be providing them with older technology, something that they would have to update in the next year or two as the availability of g routers became scarce (If you can even find them today).

So, hopefully that provides some insight into why FIRST probably decided on the router they did.

Now to answer your question...

It *should* be fine to set your router to utilize b/g/n instead of only n. Best case, you won't notice a difference. In the middle there might be some interference introduced. And worst case, it simply won't work and you'll have to set it back to n only. And in the least likely scenario, you'll set it to b/g/n and the world will explode. I doubt that will happen though

As for the gaming adapter (the part that sits on the robot) - make sure that is set up like FIRST instructs. You definitely don't want that acting anyway other than the way it should work at the competition, just to save the possible headache of your robot not working.

Thanks much! I'll let you know what happens!

[billbo911]

Originally Posted by GGCO

....we were wondering if we can just switch the settings to broadcast in 802.11g/b/n?

Not only is the new system using 802.11n, it is also using n at 5Ghz.

Now, yes you could use the system at 802.11b/g/n, but you would have to drop it to 2.4 Ghz. No big deal. Although, when you do start using b/g/n, you will be limiting the total throughput of the wireless system. You see, to support the multiple protocols, additional encapsulation is needed for the packets, thereby, eating up some of the bandwidth. Will you notice the difference?? I don't really know for sure.

I would have to agree with cabbagekid2, connecting the laptop to the DS is easy to do, fairly convenient, and works perfectly. It is also the most cost effective solution if you don't already own a Dual band N adapter. Three manufacturers make them and the all run about $70.

[pitzoid]

We picked "N" for a number of reasons, mainly the following:

- "N" supports MIMO (multiple in, multiple out transmission), if you look at the pics the blue alliance guys are circulating of the Arena Access Point (AP) you'll see it has 6 antennas, 3 of those are for the 5GHz radio which the bots will be running exclusively on. With N and MIMO we can "theoretically" get 300mbps bandwidth for the 6 bots on the field, although the individual VLAN bandwidth that each team will be on this year will be much less. This is for future addition of teams being able to get video back from their bots to the drivers station, this wasn't implemented this year for various reasons.
- Alot of the venues that we set up the FIRST FRC fields in already have established 802.11b network infrastructures, 5GHz limits possible venue interferrence issues.
- When the APs start up, they will automatically find a clear channel to establish themselves on, 5GHz has many more channels it can utilize than 2.4GHz.
- With 5GHz we can use Ethernet Bridges (i.e. the game adaptor for your bot) that don't have external antennas. thereby removing the temptation for teams to add large external antennas that could interfer with adjacent bot radio reception (RF 101)
- CISCO reps wanted us to use the APs we're using because they are the latest and greatest - they are amazing devices
- few other reasons too


I suspect this year we'll have far fewer "actual" radio "issues" than previously, systems testing so far has gone very well, but we won't know for sure till we get some regionals going. This is all new tech that will take the teams some time to get used too.

I'm very impressed with the new systems and can't wait to see what teams do with all the new capabilities, this year will be a "getting used to" period, but future season ought to be down right mind blowing wish I had this stuff when I was in High School

Good Luck all
BotBash BOB Pitzer
4FX Design

[dmlawrence]

We connected the robot to 802.11n in the 5ghz band, and left the 2.4ghz band in mixed mode for team members' laptops. We have not had any bandwith issues.

[jtdowney]

The only part that has to be 802.11n is the bridge. Setup the router to dual band 802.11g/n and that way the bridge on the robot can connect and your programmers laptops can connect.

[popo308]

We had our router on 2.4GHz b/g/n and we were having major lag issues!
(anywhere from .5-5 seconds of lag!!!)

We switched everything to wireless N 5GHz and it was noticeable improvement.(no noticeable lag what so ever)

Other teams might not have the same issue im just putting that out there....

[phobozad]

Since these are dual-band routers, the best thing to do is setup an N-only connection for the robot (following the manual) and then a separate wireless connection that does b/g for connecting computers wirelessly. Our team tested this and it works (though we usually just plug in).

[Prontopwnage]

thats why they gave you the adapers...

[MikeE]

Originally Posted by pitzoid

We picked "N" for a number of reasons, mainly the following:

- "N" supports MIMO (multiple in, multiple out transmission), if you look at the pics the blue alliance guys are circulating of the Arena Access Point (AP) you'll see it has 6 antennas, 3 of those are for the 5GHz radio which the bots will be running exclusively on. With N and MIMO we can "theoretically" get 300mbps bandwidth for the 6 bots on the field, although the individual VLAN bandwidth that each team will be on this year will be much less. This is for future addition of teams being able to get video back from their bots to the drivers station, this wasn't implemented this year for various reasons.

My emphasis

Has the absence of live video feedback been officially published anywhere? It's been my understanding that video streaming won't be available this year, but I'd like to point to an official declaration.