ViterbiAn honest answer wipes out the case for LTE-U. Assume the signal measures -80 dBm and it works. Will your LTE-U protect my Wi-Fi against interference?

The answer is no. The best data available is that half of the Wi-Fi signals are -80 dBm or lower. Qualcomm's Dean Brenner and Mingxi Fan are speaking this week at the CTIA show. I hope someone asks them.

Verizon and Qualcomm insist a test to -72 dBm detects all Wi-Fis and prevents interference. These are log scales; -72 dBm is much stronger than -80 dBm.  "LTE-U will not harm or interfere with Wi-Fi," the folks from Qualcomm and Verizon tell policy makers. (I found that or an equivalent statement 7 times, including in official FCC filings.) They go further, adding, "If LTE-U interferes with Wi-Fi, it should be prohibited." I agree.

 That's why the Wi-Fi Alliance, an industry group, proposed testing down to -82 dBm. That level does allow some interference rather than fully protecting Wi-Fi/ New York City says they find signals down to -90 dBm. A good engineer suggests -85 dBm or -86 dBm. 

Dean is paid over a million a year, I believe. It's his job to make sure questions like that are never asked. He's done such a good job even some tech reporters miss the story. Mingxi is a very respected engineer but will probably not disagree with the company line.

The four giant telcos could commander as much as half of the Wi-Fi spectrum, each taking a 40 MHz chunk. Wi-Fi is too valuable to allow so few to enclose so much of the commons. Anyone greedy in the use of spectrum harms all of us.  

2.4 GHz Wi-Fi is already crowded. 4.9 GHz is headed that way. "Some of our customers are moving to higher bands because of reliability and congestion problems in the 5 GHz band," Boris Maysel of Siklu tells me this week. Siklu supplies microwave backhaul to Webpass, recently bought by Google. Shai Yaniv of Ceragon generally agrees. 

Stanford Professors Goldsmith and Cioffi  separately spoke of problems with an excessive user in a related context. 802.11ac allows 80 MHz and soon 160 MHz channels. Even one or two users claiming that much can crowd out others. That lets the companies advertise speeds over a gigabit. As the bands develop congestion problems, this will become an issue.  

 Qualcomm refuses to accept simple tests of "Does it cause interference?" They throw in a red herring, that some Wi-Fis in the field have problems and cause interference. They then insist the primary test should be whether their proposed LTE-U are no worse.  

Wi-FI has been improving and will continue doing so - led by Qualcomm Atheros. Brenner and buddies claim, "LTE-U will not interfere." (future tense, emphasis added.) They should be testing improved Wi-Fis shipping today and in the predictable future. Instead, they demand rigged testing, using systems soon to be obsolete.

The comparison with older WiFis is irrelevant to the public interest question, Will these four companies significantly harm Wi-Fi, important to us all. It does, of course, especially if they only test at 100X the signal strength of real world receivers. Brenner knows his LTE-U would collapse on the facts, so he's leading a multi-million dollar campaign to make us look elsewhere.

"These are not the interferers you are looking for,' says the magician.

 

Newsletter

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Latest issue

 Gig LTE & Massive MIMO ushering in the Age of Wireless Abundance

Wireless Abundance is here: What the new tech means http://bit.ly/Wirelessabundance
Sprint & T-Mobile Charge to be 1st in U.S. to Gig LTE bit.ly/STMOgig  AT&T bit.ly/ATTGIG2016
Kitahara of Softbank “I am crazy about Massive MIMO” http://bit.ly/MMIMOCrazy
20 Gig mmWave, Massive MIMO & Gig LTE at the Huawei MBBF http://bit.ly/Huawei20
LTE gets to the gigabit explained for non-engineers http://bit.ly/GigLteexplained
Massive MIMO explained. http://bit.ly/WHMassiveMIMO
2017's Big Gigabit story: Qualcomm 835 is ready http://bit.ly/BigGigLTE
Doubling speed with 4x4 MIMO & 256 QAM at T-Mobile http://bit.ly/2k1gEOQ
Netgear Nighthawk M1, Telstra do "gigabit class" LTE http://bit.ly/2k1s5Gq
Spectrum price down by half http://bit.ly/Spectrumhalfoff
Dish and the telcos see big asset cut http://bit.ly/auctionlosers
Shorts on 3GPP,  NYU research, Ralph de la Vega, 5G new radio

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5GW News

dave right5G? 4G? Whatever the name, wireless is going to a gigabit, soon.  I've reported broadband since 1999 and now is the time for gigabit wireless. Catch a mistake or have news? Email me please. Dave Burstein

 

Stories worth writing

Starry may match Verizon 5G at half the cost
OFCOM in UK: Share all spectrum, even licensed
OFCOM's Boccardi: 26 GHz worldwide: U.S. goes 28 
Verizon 5G fixed tests will be only 100's of homes
Massive MIMO FD at China Uni, Tele, Huawei, ZTE

 

 

 

Datapoints

Verizon and AT&T burying price increases in fees. 

Huawei's Richard Yu intends to pass both Apple & Samsung in smartphones in five years. 

The 3,000,000,000 transistor Qualcomm 835 is a revolution. Gig LTE, incredible cameras, better VR & AR, & ... State of the art CPU, DSL, GPU, ISP tightly integrated

1,000 T-Mobile small cells 2016, 6,000 more coming. Tech Life

New $84 Reliance Lyf Wind 7S has a 5" screen, a quad-core Snapdragon, an 8 megapixel camera, and some extras. Not state of the art, perhaps, but completely usable at a modest price. 

Orange/FT 4G covers 97% of Poland, 96% of Moldova, but only 84% in France, Q3 2016. They have 113.5 mobile customers in Africa compared to 25.5M in Europe.

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