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.

 

dave ask

Newsfeed

The 3.3-4.2 spectrum should be shared, not exclusively used by one company, concludes an important U.S. Defense Innovation Board report. If more wireless broadband is important, sharing is of course right because shared networks can yield far more

It does work! Verizon's mmWave tests over a gigabit in the real world. 
The $669 OnePlus 7 Pro outclasses the best Apples and probably the new Galaxy 10 or Huawei P30 Pro. Optical zoom, three cameras, liquid cooling, Qualcomm 855 and more.
Korea at 400,000 5G May 15. Chinese "pre-commercial" signing customers, 60,000-120,000 base stations in 2019, million+ remarkable soon. 
5G phones Huawei Mate 20, Samsung Galaxy 10, ZTE Nubia, LG V50, and OPPO are all on sale at China Unicom. All cost US$1,000 to 1,500 before subsidy. Xiaomi promises US$600.
Natural monopoly? Vodafone & Telecom Italia to share 5G, invite all other companies to join.
Huawei predicts 5G phones for US$200 in 2021, $300 even earlier
NY Times says "5G is dangerous" is a Russian plot. Really.
Althiostar raised US$114 million for a virtual RAN system in the cloud. Rakuten, Japan's new #4, is using it and invested.
Ireland is proposing a US$3 billion subsidy for rural fibre that will be much too expensive. Politics.
Telefonica Brazil has 9M FTTH homes passed and will add 6M more within two years. Adjusted for population, that's more than the U.S. The CEO publicly urged other carriers to raise prices together.
CableLabs and Cisco have developed Low Latency XHaul (LLX) with 5-15 ms latency for 5G backhaul,  U.S. cable is soon to come in very strong in wireless. Details 
Korea Telecom won 100,000 5G customers in the first month. SK & LG added 150,000 more. KT has 37,500 cells. planning 90% of the country by yearend. 
The Chinese giants expect 60,000 to 90,000 5G cells by the end of 2019.
China Telecom's Yang Xin warns, "Real large-scale deployment of operators' edge computing may be after 2021." Customers are hard to find.
Reliance Jio registered 97.5% 4G availability across India in Open Signal testing. Best in world.

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Welcome On Oct 1, 2019 Verizon turned on the first $20B 5G mmWave network with extraordinary hopes. The actual early results have been dismal. Good engineers tell me that will change. Meanwhile, the hype is unreal. Time for reporting closer to the truth.

The estimates you hear about 5G costs are wildly exaggerated. Verizon is building the most advanced wireless network while reducing capex. Deutsche Telekom and Orange/France Telecom also confirm they won't raise capex.

Massive MIMO in either 4G or "5G" can increase capacity 3X to 7X, including putting 2.3 GHz to 4.2 GHz to use. Carrier Aggregation, 256 QAM, and other tools double and triple that. Verizon sees cost/bit dropping 40% per year.

Cisco & others see traffic growth slowing to 30%/year or less.  I infer overcapacity almost everywhere.  

Believe it or not, 80% of 5G (mid-band) for several years will be slower than good 4G, which is more developed.