Bob's Adventures in Wireless and Video Headline Animator

Saturday, January 22, 2011

Integrity and Technical Claims

Truth, integrity, honesty.

These are simple words. Concepts we are taught as children. Our parents punish us for lying. Our pastors told us it was a sin to lie. We all know right from wrong, yet when it comes to marketing, all the rules go out the window.

In wireless the claims get really wild. Range, throughput, latency, reliability, security...pretty much any attribute for a wireless link you can imagine has a set of outlandish claims made about it. When specifying wireless products the first rule is that they are called the "law of physics" because they have been proven to be true. Light travels at 299792.458 km/s. Modulation schemes yield a fix throughput based on the channel width and number of points in the constellation. Energy dissipates over distance. Matter has known density.

Marketeers are great at making claims that are difficult for end users to really evaluate. Take WiFi. Most of you have heard about 54Mbps, 108Mbps or even 300Mbps wireless. These are impressive numbers, but they are based on totally unattainable conditions. The 54Mbps number which most of us are familiar are with for WiFi is the theoretical maximum capacity of a 64-QAM modulation carrier in a 20MHz channel under ideal conditions. When you actually establish a link at 54Mbps you might actually achieve UDP throughput of only 35 to 40Mbps and TCP throughput, with overhead, of 25 to 28Mbps using 802.11 a/g.

It would be like buying a car with a EPA fuel efficiency rating of 54 miles per gallon, but where the manufacturer knew that you would only ever be able to get 25 miles per gallon. Would you feel ripped off? I sure would.

Range is another area in wireless where marketeers are great at bending the truth. Claims of 1 mile with low power transmitters attached to low gain antennas are common. Many manufacturers make range claims based on maximum transmit gain and receive sensitivity, which may be achieved using DSSS modulation with data rates of 500kbps TCP. Yet consumers buy equipment based on the the maximum range assuming that they will also achieve maximum throughput at this range too. Modulation complexity causes more energy to be dispersed across more sub carriers, meaning the faster you go, the shorter the distance given the same amount of energy.

We have taken a stand at HauteSpot to tell the truth. We pay a price when we do this. We tell our customers what throughput and range they will actually achieve under real world conditions. Our competitors continue to post theoretical specifications or completely avoid discussing range and throughput entirely. So when we say 35Mbps TCP throughput at 1 mile, that is what we will deliver, not a theoretical throughput of 108Mbps.

Make sure that you are comparing apples to apples. Make sure that the claims are substantiated through math. Use our , or our competitors link calculators to validate throughput calculations.

Tell the truth, accept the laws of physics, and do your math and you will be fine. 

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