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Showing posts with the label Transmit Power

Five Facts About 6 GHz Wi-Fi

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Two pieces of important news hit the wire recently: the 6 GHz band was approved for Wi-Fi, and alcohol sales have skyrocketed .  Combine the two, and what do we get? A five-pack of Coors Light Cold Hard Facts about Wi-Fi in the 6 GHz frequency band. Editor's note: This is a relatively long post, but 6 GHz Wi-Fi is an undoubtably robust topic. If you have questions after reading this blog, comment below or contact Ben via email or Twitter using the information below, and Sniff Wi-Fi will address those answers in a future post. We may be knee-deep in a global pandemic, but that doesn't mean your humble blogger can't brew up a post on the topic of 6 GHz Wi-Fi. Wi-Fi professionals will soon have unlicensed frequency available in the 6 GHz band. Here, then, are five facts to know about Wi-Fi in the soon-to-be-available 6 GHz frequency band. Fact #1: The 6 GHz band adds 1,200 MHz of spectrum for Wi-Fi The Federal Communications Commission (FCC) is the federal ...

Wasted Wi-Fi Q(-Tip)&(802.11)A: Transmit Power, Conducted Power and EIRP

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Last week's blog about Wasted Wi-Fi prompted some questions about AP transmit power in the enterprise.   Let's answer some of those questions by doing a little Q(-Tip)&(802.11)A, an exercise in which we watch a Q-Tip video before Answering a few questions about Wi-Fi. You've seen the Q(-Tip), now on to the A(nswer)s: Wasted Wi-Fi is all about APs and/or stations making inefficient use of a Wi-Fi channel.  When Wasted Wi-Fi happens, either data rates are lower than they should be, or Retry percentages are higher than they should be. The Q becomes, where do equivalent isotropically radiated power (EIRP), transmit power and conducted power fit in? The A is, higher data rates and lower Retry percentages tend to happen when signal-to-noise ratio (SNR) is higher, and higher EIRP/conducted power/transmit power leads to higher SNR. In other words, if you talk louder, then people hear louder.  When people hear louder, they have a better chance of being...

Are You(r APs' Transmit Power) Still Down? Raise 'Em Up

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Remember me? (lyrics NSFW) Too many enterprise Wi-Fi deployments experience Wasted Wi-Fi.   Wasted Wi-Fi is what happens when an enterprise wireless network offers users lower performance than it would under an optimal configuration. Today, the most common culprit of Wasted Wi-Fi is low AP transmit power.  So, if your AP transmit power config is Still Down, Raise 'Em Up. I've noticed a lot of Wasted Wi-Fi recently.  Situations where, given the distance, client density, and physical environment, the Wi-Fi should be faster.  These are situations where, irrespective of issues that may exist in the infrastructure equipment or design of the wireless LAN, client devices are getting worse performance than they should. By its definition, Wasted Wi-Fi lays entirely at the feet of those who configure enterprise Wi-Fi settings.  The good news is, that means Wasted Wi-Fi is solvable without expensive and time-consuming changes to the wireless LAN ...

Testing AP Transmit Power Using AirMagnet

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If there's one recent change in the Wi-Fi world that has brought some heat and light to your humble blogger's cold, dark heart, it's the awareness of device differences.  But there's a difference between understanding that Wi-Fi devices have differences and creating an infrastructure that supports them.  And an important step in setting up a good Wi-Fi infrastructure is finding out whether the APs' transmit power is too high, too low or juuuuuuust right.  It has long been the recommended to have matching transmit power for devices engaging in two-way wireless communication, but with Wi-Fi that rule is often broken.  Breaking the rule is understandable because Wi-Fi environments are often vendor-neutral.  Most Wi-Fi deployments are not like the beaches of Normandy, where everyone had the same model of radio. Sometimes we need really, really good Wi-Fi, and matching the transmit power levels of APs and stations can go a long way towards fulfilling that need....

Mighty iPhone Power Ranges II (With iPads)

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About a year and a half ago, yours truly wrote about WiFi transmit power levels in iPhones .  Things have changed since then.  And possibly the biggest change (to iPhones, at least) is how aggressive iPhones are in modifying transmit power levels.   In the "Mighty iPhone Power Ranges" blog post, I wrote about the value of setting AP transmit power levels to approximately the same level as client/station device power levels.  Over the past year or so, more and more client/station devices have started using adaptive power levels.  A typical implementation would force a device to lower its transmit power when receiving a strong signal from the AP and raise its transmit power when the AP's signal is weak. The unanswered question is, "just how vast are these ranges of transmit power levels?"  Can a smartphone or tablet go as low as half power?  10% power?  0.0001% power?  Those differences could have a major effect on a WLAN in...

Mighty iPhone Power Ranges

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Oh, those darned iPhones. Can't live with 'em, can't keep your job without 'em. The vagaries of iPhones and other station devices are the most difficult part of managing a WiFi network, but there are some things that can be done on the infrastructure to try to make your stations work better. One of those things is lowering your AP transmit power to a level that more closely matches your client station's transmit power.  My main man G.T. Hill (of Ruckus Wireless ) recently wrote a blog post discussing why this post is bullshit. Now I'm going to tell you why his blog post is bullshit. (sorry, G.T.) G.T.'s primary point is that is is borderline mentally handicapped (politically correct term) to turn your AP's power down. His theory is that even if your client stations transmit at low power levels, having a high AP power level at least allows the from-AP data rates to stay as high as possible. (G.T. goes on to add that most traffic is downstream, th...