Currently viewing the tag: "2×2 MIMO"


The future billboard Working on many things at the same time, the tunnel vision sets in, so every once in a while, I try to take a I step back and reflect on where we are in LTE land.

What I see is a early market that has yet to find it’s purpose in life. Yeah yeah, consumers are buying devices like Samsung Galaxy III/IV and Apple iPhones that are LTE enabled at a rapid clip in the US, but at this point the device is driving the sale not the LTE itself.  

There have been a couple of interesting developments, such as Audi and GM deciding to leverage LTE for in car data links and even going as far as choosing to use VoLTE for voice. That’s a major step towards finding the killer app for LTE.AudiLTE_connect

However, those developments are in progress and have not actually resulted in any traffic yet, both are expected in 2014.

Consumers are driving traffic today. Looking through some public data, like Root Metrics reports on average data speeds, I am reminded by how inefficient the networks are.

Verizon vs AT&T LTE

Here are some results from that more or less concur the performance observed by Root Metrics.
iPhone 5 Verizon 4G LTE Speed Test Results
  • 8.52 Mbps download, 13.87 Mbps upload, 39 ms ping
  • 7.47 Mbps download, 13.70 Mbps upload, 38 ms ping
  • 10.21 Mbps download, 13.81 Mbps upload, 38 ms ping

iPhone 5 on AT&T 4G LTE Speed Test Results

  • 9.32 Mbps download, 13.69 Mbps upload, 47 ms ping
  • 9.11 Mbps download, 13.88 Mbps upload, 47 ms ping
  • 9.69 Mbps download, 16.20 Mbps upload, 48 ms ping
  • 8.96 Mbps download, 15.83 Mbps upload, 40 ms ping
iPhone 5 over Wi-Fi (Comcast Blast 50 Mbps) Speed Test Results
  • 8.52 Mbps download, 13.87 Mbps upload, 39 ms ping

So it’s hard for me not to notice a couple of elements to this story. Firstly, the mad rush to provide LTE coverage (schedule driven) has been, understandably, at the expense of quality. Here’s the difference:



The peak throughout of a 10MHz 2×2 MIMO with 3 PDCCH symbols, 5% extra overhead and 10% retransmissions channel is 58Mbps, with SIMO at 35MBps. So practical rates in the field are 26.4% of the peak rates with retransmissions. 

It doesn’t take a math genius to realize that 26.4% efficiency is an ROI buster.

So with 50,000 eNBs they currently carry maximally 750GBs over their RAN instead of the 2.9TBs they have already paid for. Simply extrapolating from Cisco’s 2013 VNI report, I get a projected data explosion like this:


Uhhh, isn’t the datapcolypse supposed to need about 800GBps  per operator in 2017? They’re blowing 2x that amount with poor efficiency!


 Making matters worse, ATT and VZW are starting to throw some additional spectrum into the markets. VZW recently announced they are adding 5000 eNBs with AWS spectrum, most likely ‘hotspots’ costing them $3.9B in a one time AWS spectrum buy plus ~$15K/eNB = $75M annually for the additional carrier. ATT has done a series of multibillion dollar deals to add in more 700MHz spectrum. 

ATT has been spending something on the order of $22B to build out and maintain an extensive WiFi network they claim offloads their LTE networks.

Here’s the rub, improving the efficiency to move their average is not as expensive as the offloading or spectrum additions they are doing. One more thing, SON should be doing some of the work for them in a very OPEX friendly manner. 

By cleaning up the network, making it more efficient, there is going to be an induced demand, yes, however having users use your product is not necessarily a bad thing. (I’ve already complained about pricing.)

Let me just say this is crazy. Reducing the network efficiency effectively increases your cost to provide service thus degrading margins. There are tons of levers to pull in the protocol as it is written, with improvements on the horizon. Wake up!

Ladies and gentlemen, the captain has illuminated the fasten seatbelts sign as some turbulence and or distruption is expected in this market.. 

PS: Verizon and ATT, I will make myself available to send you an invoice for, say, $1-2B and will turnkey a project to give you another 800GBps. You can sell your recent investments and return the money to working capital or the investors, or hold them for getting to 1GBps over the air with carrier aggregation in the future… (ok time for me to get back to work…)



So I’m trolling the internet during a conference call and whoa, what’s this? An article in CNET about LTE speeds. Seems like everyone is interested in LTE all of a sudden. Anyway here’s the page:

 Don’t get me wrong, I laugh at Verizon and AT&T’s LTE implementations but this article makes me want to cry. The REAL reason the speeds in NYC are averaging in the 20MBps range and Sydney is like 40MBps is…


Verizon and ATT have 1/2 the bandwidth deployed that Optus (Australia) does! (FCC Hear that?) The US operators’ Verizon (Band 13) and ATT (Band 17) have deployed 10MHz channels in lower 700MHz with 2×2 MIMO whereas Optus (Band 3) has a 20MHz channel with 2×2 MIMO. Double the resource, double the rate.


I’ll give you one guess why LTE usage in the US is about to explode? Say it together… ready… 

Yep, iPhone 5. If the rumors are true and they follow the precedent of implementing LTE in iPad, then it’s reasonable to assume that iPhone5 is going sport LTE. Now, per our previous discussions, the design choices will guide how many markets a single SKU can support (hopefully they chose wisely) but I am going to be optimistic and think it would support 700, 800, 950, 1800, 1900 and 2100 handily. The next challenge would be global roaming but let’s hash that out later. 

From a utilization perspective, if 50% of the iPhone users are in urbanized areas where LTE is deployed, it’s safe to assume that most of these will be using LTE instead of HSPA+/EVDO. The data model shows that iPhone users are averaging around 1GB per month currently so I would expect that to nearly double quickly given the new capabilities of the LTE channel.

Here is our previous discussion regarding how the iPad parts were chosen BTW.

Next, prediction, at the application level, video chatting may finally get BIG thanks to Apple’s Face Time.   They have done a good job of making video conferencing simple to the point I think people are likely to begin using this en masse’ soon. Ohhh yeah, Contrary to the doom and gloom types, Face Time over LTE will not crash the network. It’s really a small bandwidth service as compared to high definition streaming (gaining popularity) or downloading those huge work PPTs and PDFs. (uh huh) Factor in the general mobility and individual sectors won’t stay loaded…more likely people will go indoors anyway and end up on WiFi…but even when out and about, Face Time WILL NOT CRASH LTE NETWORKS. 

Simple example:

1 sector capacity= 70Mbps (10MHz 2×2 MIMO such as Verizon or ATT) … Toss out 50% for no SON, poor optimization etc… = 36Mbps…

1 FaceTime user bandwidth 175Kbps (peak) x2 (Uplink and downlink) = 350Kbps (numbers from fairly popular mouths range from 392Kbps to 150Kbps)

(See this interesting link on Face Time bandwidth and this one too… )

36Mbps/350Kbs = 102 simultaneous (instantaneous), non throttled, FaceTime users PER SECTOR. A typical site usually has 3 sectors, sometimes 4 or 6…

So if you are a tech blogger and go to a major conference or iUnveiling on campus, and there are more than 102 smokers outside since you are likely to be on WiFi inside, you may find yourself competing for bandwidth but the hogs are more likely to be YouTube streaming (have seen 3Mbps!) and not necessarily just FaceTiming…



While the USA has been launching its’ 2×2 MIMO based, 10MHz FDD networks that peak in the 70Mbps range, but deliver about 20s….Deutsche Telekom announces they are launching their 100Mbps service in Europe.  Honestly I’m jealous. There’s a big gap between what I’m using and what they are advertising… sigh…  oh yeah…all this for EUR 9.95/month! Full PR Below… yeah yeah, bigger area blah blah….100Mbps…T-Mobile please follow HQ’s lead!!


High-speed surfing for smartphones

Aug 30, 2012

  • LTE Speed option cranks speed up to 100 Mbit/s
  • Option available with all Complete Mobile rates for an additional EUR 9.95/month
  • Telekom customers always access the best available network

Fast, faster, Telekom: with the new LTE Speed option, Deutsche Telekom customers can surf the Internet with their smartphones at speeds of up to 100 Mbit/s.
No other provider in Germany currently offers this speed. The LTE Speed option can be purchased from September 4 for EUR 9.95/month with all Complete Mobile rates. The data volume included in the selected rate also doubles, increasing your surfing pleasure.

The new option is being launched at the same time as the first LTE-capable smartphones, such as the HTC One XL and Samsung Galaxy SIII LTE.
The LTE Speed option’s contract period is three months.

But Telekom customers will enjoy the benefits of the new LTE high-speed network even without the new LTE Speed option, with speeds of up to 21.6 Mbit/s. All contract rates are technology-neutral, which means customers can always use the best available network.

Telekom continues to invest heavily in the upgrade of its cellular network. By the end of this year, the company will have linked 100 cities to the high-speed LTE network, putting its customers on the fast lane of the mobile information superhighway. More than 10 million customers in rural regions already enjoy fast mobile broadband through LTE 800. In addition, Telekom offers download speeds of up to 42 Mbit/s in its entire UMTS network, reaching some 87 percent of Germany’s population.

Experience our products and services live at IFA in Berlin from August 31 to September 5 at the Deutsche Telekom stand in hall 6.2. Deutsche Telekom’s entire presence at the trade fair is carbon-neutral: All CO2 emissions generated in setting up and operating the stand are offset fully by carbon-reduction projects abroad. 

About Deutsche Telekom
Deutsche Telekom is one of the world’s leading integrated telecommunications companies with almost 130 million mobile customers, 33 million fixed-network lines and over 17 million broadband lines (as of June 30, 2012). The Group provides products and services for the fixed network, mobile communications, the Internet and IPTV for consumers, and ICT solutions for business customers and corporate customers. Deutsche Telekom is present in around 50 countries and has over 233,000 employees worldwide. The Group generated revenues of EUR 58.7 billion in the 2011 financial year – more than half of it outside Germany (as of December 31, 2011).

I am working with a regional operator’s LTE network design, and I was comparing our design to some of the publicly released information available about the competitors and, well I was a little surprised at the early results. I think I’ve boiled it down to 2 charts.

Firstly, as a matter of review, ATT and Verizon have very similar resources currently dedicated to the deployments. ATT is deploying 2×2 MIMO using FDD on lower 700MHz, Band 17 (which is only Channel B + C of Band 12) which facilitates 10MHz channels with their existing sites without RET antennae widely deployed yet. VZW has deployed/is deploying essentially the same thing in Band 13 (upper 700MHz.) So knowing what we know about 2×2 MIMO we can baseline where they are.

The first chart is a standard SNR vs throughput chart. As you will see most of the results reported are achievable with only 5dB SNRs.

Here is the throughput comparison.


The biggest takeaway for me on the forward link, neither is really achieving an expected baseline level yet. Not even close. They are about 26-28% off the median so there’s some red flags to note in their approach. Is it all due to the early rollout phased spotty coverage? No, many of the measurements were made at airports and core areas for VZW (maybe why it’s slightly higher) and for ATT the have limited markets rolled out so the tests are only in the preferred areas anyway.

After looking at the throughput, it’s only fair to derive their efficiency in terms of bps/Hz. Ready?

It’s directly related to the throughput, but it’s still eye popping to see as efficiency. Now granted, I didn’t throw in the targeted because that only a reference number that’s synthesized with McDonald’s patties in a lab and therefore not that relevant.

There’s a small caveat to throw out and that’s the device performance. Surely the device performance will improve over time.

My takeaway here is all those body shops importing engineers from the Middle East, Asia and so on need to speed dial their Verizon and ATT lunch buddies and work hard to get some of the ATT and Verizon optimization project dough. OK seriously, ATT and Verizon seem to have lots of bottlenecks in their LTE networks that are needing optimization. Question is, is network equipment maturity and device maturity all there is to improve here or are there are things to address?

Oh, and just by looking at this data it’s easy to see that these networks are clearly not under near realtime SON control either. And what will these numbers look like at higher frequencies, like for Sprint and Clear? Hmmm…

Nexius is doing a good job marketing their body shop chops with a new LTE info graphic …but they forgot to mention the things above though, oh well….

A Nexius Infographic - Seven 4G LTE facts that might surprise you

 Cognovo and Rhode & Schwartz are demonstrating Release 10 over the air at Mobile World Congress. Cognovo is putting their CDC160, a Software Defined Radio (SDR) processor to work as the baseband processor and Rhode and Schwartz (R&S) is chipping in their Vector Signal Analyzer SMU200A and Option K85 as the front end to demonstrate carrier aggregation of 2 x 20MHz LTE carriers for an effective 40MHz channel over the air. This should be pretty cool to see just from a novelty standpoint. 

 Let’s see, 40MHz of Release 10 should peak (PHY) from about 600Mbps downlink and 270Mbps uplink to 144Mbps/43Mbps (2×2 MIMO) based on the configuration they have set up.


Links: Cognovo, Rohde & Schwarz



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