The tortoise or the hare for Wi-Fi?

The tortoise or the hare for Wi-Fi?

Summary: The never ending quest for speed has brought about the need for a new high-speed wireless LAN standard called 802.11n.

TOPICS: Networking

The never ending quest for speed has brought about the need for a new high-speed wireless LAN standard called 802.11n.  MIMO (Multiple In Multiple Out) based wireless data transmission technology is the technology behind the new 802.11n standard but MIMO means different things to different companies that are pushing hard for their own version of MIMO for 802.11n ratification.  From a marketing standpoint, everyone is jumping on the "MIMO" and "pre-N" bandwagon whether they use any kind of MIMO or not.  The term "pre-N" has no real meaning and only serves to "imply" eventual compatibility with the 802.11n standard.  Such a promise is impossible to keep because there hasn't even been a draft standard defined and no one knows what the final standard will look like.  All of this marketing effort serves the single purpose of convincing customers that they should buy product X because it has the "N" factor for superior speed and superior range but is there life beyond Wi-Fi speed and range?

While speed and range are very important enhancements in the evolution of Wireless LAN technology, it isn't the only thing users need to worry about.  One aspect of Wireless LAN enhancement that has been largely overlooked is the stability factor because it's much easier to market the concept of speed and range.  Take the most recent MIMO Wars Round II product review from Tim Higgins and it's easy to get caught up in the speed and range race.  But if we look closely at Tim's results, we see that it isn't the speed leader that leads the stability race.  While the competition was able to sustain faster average throughput, Ruckus Wireless was the slow and steady leader because they provided stable and usable throughput at any location tested.  With 10 mbps of stable throughput at the farthest reaches of the house, that's more than enough to deliver smooth and steady High-Definition video content.  You might be able to download a file from a local PC faster with the other products but what good is it if the connections cuts in and out when you're trying to deliver voice or video?

Ruckus recently changed their name from their old name Video54 and began selling their own line of specialized Smart Antenna Access Points and Ethernet Bridges [at left] that differentiate them in the way that they handle video streams which are highly sensitive to any kind of delay or packet loss.  Ruckus primarily caters to IPTV vendors which are becoming popular in places like Hong Kong, Europe, or parts of the US like to use multicast UDP streams with minimal buffering.  The products are really not available to the general public but their Smart Antenna technology is present in the first generation of Netgear RangeMax products.

Note:  Multicasting allows video streams to be efficiently broadcast to a large number of people while only taking up a fixed amount of bandwidth.  UDP is a send it and forget it technology where any data loss is uncorrected so any kind of packet loss immediately show up as video loss.  TV streams have to have minimal buffering because buffers cause unacceptable delays when guys like me flip channels like there's no tomorrow.

I was initially a skeptic of Smart Antenna technology because I had spent so much time in the last few years testing Wireless throughput versus range performance.  Since I raved about the throughput and range numbers that some MIMO products were getting, I had several Smart Antenna startups contact me on why I needed to consider their Smart Antenna technology.  Since Ruckus (Video54 at the time) was the only startup with a production product and a successful one at that, I decided to take a serious look at their technology.  Ruckus argued that their Smart Antenna technology was more resilient against Radio Interference from neighboring Access Points and nearby Microwave ovens because of the way that their Smart Antennas seek the best path for signal propagation.  In addition to the Smart Antenna technology, the Ruckus Access Points can also prioritize voice or video packets which aren't normally found in consumer grade products.

To verify Ruckus' claims, I visited their "laboratory" which was a massive state-of-the-art house owned by the chairman board member of Ruckus.  I also brought a spectrum analyzer to verify the radio noise levels.  The test environment had Access Points in the downstairs bedroom transmitting a UDP stream of the DVD Shrek II to the kitchen upstairs.  When we tried this with a D-Link Atheros first-generation MIMO Access Point with a Centrino notebook on the client end, it failed miserably before we even got to the kitchen.  The video went to hell before we entered the kitchen.  When we replaced the Access Point with a Ruckus Access Point while keeping the Centrino client, it worked nearly flawlessly through the kitchen.

To make things interesting, we then tried to cook some water with the Microwave oven within 8 feet of the notebook and we managed to kill the video transmission.  This was understandable with the high amount of 2.4 GHz inference coming from the Microwave.  Then we tried the same test with the Microwave on using the Ruckus Access Point on the transmit end and the Ruckus Smart Wireless Ethernet Bridge on the client end and we were able to watch the movie with minimal video loss.  In addition to the Microwave torture test, we also tried to transmit three data streams over the same 2.4 GHz channel and the Ruckus Smart Antenna solution handled the interference the best.  This last test is very relevant in the real world because there are only 3 channels to work with in the 2.4 GHz band and neighbors often conflict with each other and most people don't even bother to switch from their default channel 6 or channel 11 configurations.  For further verification, I took a set of Ruckus Access Point and Bridge home to run more tests in my own environment so I'll be following this story up with more results.

Having seen the benefits of Smart Antenna technology, I'm convinced that the new benchmark for Wireless LAN performance is the combination of throughput, range, and stability.  Speed and range alone isn't good enough if a little interference brings the product to its knees.  I asked the reining speed and range king Airgo Networks if there is any reason that Smart Antenna technology couldn't be implemented in the same product to complement Airgo's high-speed chipset and they responded no.  Such a product doesn't exist yet, but I'll be the first to buy one when it does.

Topic: Networking

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  • Faraday's Cage

    And what will it do, when the signal is (partially) blocked by a Cage of Faraday?
    Arnout Groen
    • Nothing will help you there

      If you go as far as blocking out 99.9% of the signal, nothing will help you there.

      The smart antenna design lets you get around most RF interference far better than any conventional antenna.
      • It's not that worse

        The problem is, that there're a couple of stables between the WiFi base station and the send/receiver which is connected to my PC. Both can link to eachother, but transfer rate's are awfully slow.
        Arnout Groen
      • It's not that worse

        The problem is, that there're a couple of stables between the WiFi base station and the send/receiver which is connected to my PC. Both can link to eachother, but transfer rate's are awfully slow.

        Maybe it's an idea to use the satelite for send and receive. Just like the militairy. Can't you test something like that George? Finding out if the satelite transfers data faster than a T1 backbone connection.

        Either way, it's going to be an issue for next year, because i'm to busy rebuilding my house.
        Arnout Groen
        • Satelite is horrible

          Ping times are in the 1000 ms range. Any Wi-Fi device (even 802.11b) will exceed any broadband connection. Satelite links are the worst in response times of any kind of broadband connection. It's great if it's the only thing you have, but should always be the last choice from DSL or Cable.
    • Faraday Cages are only for the rare bird

      Faraday cages are very expensive to build in regard to an entire room. A small desktop version shouldn't affect the wi-fi signal through a typical home or office very much, if at all. The key is to not have the access point anywhere near it.

      In my work with information warfare operational techniques that are used by various alphabet soup agencies (US), I see a lot more room sized Faraday Cages than the average IT person (not to mention that most people have never even heard of Faraday). Most are built with aluminum sheet, but I have seen carbon foam composites used with some success.
  • Here's George!

    Finally an article! Thought you left the country. ;)
    And I can't even pick because I don't know anything about the subject!

    Wish you'd write an article 'bout 802.16 WiMax.

    Interesting article. Thanks George.
    D T Schmitz
    • Sorry, still finishing up the move

      Sorry for the delay, I'll be on with a full line up this week. You'll get your controversy this week :).

      Moving house is something I don't wish on anyone. It's been crazy and my DSL is finaly up at home today. I just hooked up the modem now.

      As for WiMAX, I don't know if you've seen these or not.
    • Do the WiMAX Mobile investigation

      [Wish you'd write an article 'bout 802.16 WiMax]

      Find out what's holding it up!
      Roger Ramjet
  • Actually we are closer to an agreement on 802.11n ...

    ... then is implied here. The current draft will be submitted to IEEE in January by the WFA, (WiFi Alliance). There is finally agreement amongst the competing sides. Anyone building Pre-N with that draft will most likely be compatible with the final standard wich should be ratified next year.
  • I agree about stability

    I agree that stability should be a major factor - I've had times where even a strong signal doesn't guaruntee bandwidth.
    • That's where smart antennas help

      When you have a strong signal, you can still face interference. Smart antennas can work around interference much better than dumb antennas.
  • users

    what about dumb users?