From the monthly archives: "November 2012"

 Now the Blogosphere is incessantly echoing this story … I first noticed in GigaOM, their story is really Fear Uncertainty and Doubt (FUD) extremist journalism (how’s that?) Their story is linked below.

Voice Calls Over 4G LTE Networks Are Battery Killers

The key quote is:

The results of those tests should give carriers and consumers pause. The average power consumption for a 10-minute CDMA circuit-switched call was 680 milliwatts (mW), while the average consumption for a VoLTE call of the same duration was 1,358 mW. That’s double the power drain. Spirent estimated that on a full charge, its test smartphone could support 502.6 minutes of talk time using CDMA only, but the same charge would deliver just 251.8 minutes of talk time using VoIP on the 4G network.

So as a quick refresher, VoLTE (Voice over LTE) calls are similar to the 3G/2G counterparts with VoCODING and so on, but are carried like VoIP, over LTE packets back to the network, where instead of a circuit switch there is an IMS for calls etc etc…

Some related info from before…

Mobile Wireless HD Voice Today and VoLTE in the Future

 Firstly measuring battery consumption is a brute force thing to do here but it does expose the maturity of VoLTE clients at the moment, so I will give them that. The FUD part of it is that the client on the device they tested is really not like anything on a 2G/3G voice phone today. Most of the grunt work of a 2G/3G call takes place in hardware on the phone, with the phone’s UI being the only significant software piece. Voice calling has been optimized in hardware over the years to consume very little power as there is no need for memory, CPU etc… 

On the other hand, the current crop of VoLTE clients are running the whole VoLTE protocol ‘stack’ (SIP + more) in software plus running the VoCODING at this point in software. The bottom line is today’s VoLTE clients are CPU hogs that do use CPU, memory, UI, etc…but are very UN-OPTIMIZED. Let’s give the developers a year or two to optimize the solution and come back and measure. In the end, there will be no difference in power consumption on average.

Let’s stop getting hysterical!

Hope everyone had a great Thanksgiving if you are US based, else hope everyone enjoyed having the US off. Happy ThanksgivingI have a number of big, urgent and interesting projects going on that each have NDA type of agreements and so between the time and the mouth shutting agreements, it is severely putting a damper on my ability to bring attention to events going on in our world. This too shall pass and I will sputter out some tidbits here and there for the next few months.

Interesting things catching my eye with respect to (wrt) the wireless world include:

eSRVCC is an improvement to the SRVCC where instead of having the home network be the voice anchor, the visited network anchors aspects of the voice calls. This will streamline network-network communications and reduce latency, thus improving end user experience.
Here are before and after network diagrams.
I think the debate about LTE vs FTTH pricing is an interesting one. The intuitive answer is there is a competitive advantage to wireless however in the US there is a major premium on wireless data pricing. This is a very interesting thing that I’m hoping globalization can help. If there were true price competition (assuming identical services) then I bet the pace of change would be astonishing. Can’t wait to see how this goes in Japan.
The FCC is debating allowing DISH use the PCS band adjacent to the G block (H block) for LTE and this is, in and of itself is mildly interesting. But more interesting is the impact it could have on DISH’s plans to use their adjacent spectrum for LTE. Remember DISH came up with 20×2 MHz channels with the acquisitions of DBSD and TerreStar earlier. The FCC is open to DISH’s use but they are looking to add adding power restrictions in the UE TX band…to me limiting DISH’s opportunity, for example to deploy TD-LTE. I’m not sure why the filtering requirements cannot be sharpened on both sides of the spectrum but they never seem to do this. (Band 12 and Channel 51) 
The transformation of the mobile ecosystem is under our noses. See this chart.

Finish and Irish auctions of 800MHz are interesting just to help ecosystem for infrastructure add low bands…hopefully that ends up adding 700MHz capability to everything too.

Have a good one…Oh two more interesting tidbits…

Network Planning for LTE-Advanced

2012 LTE NA: What is a “Thinking Network”?

 So when I saw the article in the MIT Technology Review yesterday, I knew there would be some hype around it. Fast forward about 24 hours and the hysteria machine has really started up, see for yourself in Engadget and Fierce Wireless posts.

Their hysteria is that LTE networks are easy to jam, using easily procured equipment, the number thrown out was $650. See this quote: 

According to the research group’s director, Jeff Reed, a single malicious operative with a hot briefcase and a bit of know-how could take down “miles of LTE signals.” If the attacker splashed out on an amplifier, they could cut off reception for thousands of people across a whole city or region.

Addendum: This paper was created as a submission to NTIA regarding Public Safety LTE. It is here.

Well that’s easy to take out of context. Any electromagnetic transmission is easy to block/jam when you think about it. So this type of hype brings out a huge irritation with me, and that’s the blogosphere’s copy/paste system to fill their site and help generate page views. If a LASER is Light Amplified by Stimulated Emissons of Radiation, then HypASER blasts are due to Hype Amplification by Stimulated Emission of Ridiculousness

Let’s all get wound up about LTE jamming because hundreds of bloggers will copy and paste the MIT article in various ways to generate some hype for you.

OK, I’ll stop nagging…but the blogosphere is not helpful here.

I’ll explain my logic.




It’s not far fetched to imagine hackers or terrorists or criminals whatever actually doing this. The parts required are mostly off the shelf and the knowledge is easily obtainable. This same approach as described for LTE works the same way with GSM, although CDMA/WCDMA is a bit more resistant but not immune. Creating noise in the RF domain, particularly in the channel of interest happens all the time. For example, an anti N order passive modulation (PIM) war, caused by shoddy work, bad cables, antennae or RF equipment, rusty bolts etc… is being fought now because operators realize the generated noise reduces throughput and thus reducing data capacity and therefore limiting revenue. 

For LTE networks though, the laws of Physics still prevail (in our universe) and a bad person with a jammer will be likely using low power, or having low effective gain (hard to carry around a 9′ antenna all the time), if they are low to the ground (where maximum effect could be achieved.) Again not impossible at low power/gain so you could say the sphere of influence is going to be very narrow if they target the eNB TX band. If they target the eNB RX band they may have more success but it’s effectiveness is wholly dependent on the location of the UE’s trying to communicate to the eNB. THIS IS NOT THOUSANDS UNLESS IN A WELL DEFINED/CONTROLLED ENVIRONMENT/VENUE LIKE STADIUM POSSIBLY AND IS VERY LIMITED IN SCOPE.

Worst Case

Let’s go further and say that the perpetrators have now worked out how to maximize their gain to compete with the nearly 1KW ERP from the base stations. Got to find a favorable (high) location and have lots of gain, so huge antenna or high power or both. What spectrum are they broadcasting in? 

700MHz rogue transmitters may affect larger areas due to propagation characteristics than say 2100MHz. Either way, there is redundancy in most of the mobile world as networks are generally overlaid on a technology basis, so a failed 4G connection moves back to 3G. 


So I thought it would be fun to review the many existing countermeasures that could be useful in defeating the perps. Firstly there is physical redundancy. Multiple networks, multiple LTE carriers, multiple sites more MIMO (antennae.) More spectrum to cover increases the perp’s setup complexity. They would need to deny 3G networks too. In most cases mobiles could search and find another network to serve them. More sites include wifi and small cells. Small cells alone could be a very very effective countermeasure. They don’t have to be at the same channel bandwidths, MIMO ranks (ex 4×2, 4×4, 8×8 etc…) or could/should operate in different channels or even utilize TDD modes instead of FDD modes or vice versa. This in an of itself would be very difficult to overcome.

It should also be noted a good defense would be detection. Sudden noise rises are reported in the link prior to all out failure. Beyond that it is wise for operators to have monitoring equipment placed in the link to guard against interference anyway. These external monitors help reduce site visits and so on for common unintentional interference could be the canary in the coal mine for intentional interferers. SON could also help. SON controllers would detect changes in noise and traffic levels, if a suitable outage threshold can be defined, then once the threshold is met, SON could automagically change tilts/increase gains/power in neighboring sectors or sites to help mitigate for the subscribers. 

Not out of the question but a little more resource intensive would be doing things like manual intervention. Examples include turning the cells in affected area off, alternative bandwidths/growing multiple channels or switching modes to TDD mode so as to be able to manually locate the noise sources. A more passive but effective countermeasure would be to implement LTE Roaming such that mobiles always have an alternative.

Let’s not forget that Release 10+ specifications (LTE Advanced) include a feature called Carrier Aggregation that allows operators to operate a virtual large channel over multiple smaller ones. This by very definition is more robust to interference than less bandwidth. Your milage will vary of course but it’s helpful.

Interference cancellation techniques are going to become widespread on UE and eNB to dramatically improve performance and this approach could help a lot.

If the perps are capable of ultra wide band, ultra high gain interference then they are probably more like nation-states and you have a much bigger problem on your hands than just the wireless communication interruption…although those small cells are probably still carrying traffic close by…

Thinking through this for Public Safety, heck this story could be created by a large operator trying to prevent Public Safety from operating their own LTE networks but I digress…the standards could be improved to allow for improved control channel redundancy/resiliency beyond a doubt. 

I guess I refute the numbers but not the principles of the original article. It’s going to take a lot more than $650 to effectively take out thousands of LTE users. LTE networks are probably more susceptible to IP hacks than RF hacks. However the blogospheric focus is on the (hot) air portion. Hopefully the hysteria will die down soon. Ugh…

Ahead of the signaling show (who knew?) that starts tomorrow … I have been noticing a flood of information including various press releases about LTE roaming. I don’t have much that I can say publicly other than what I can observe in the public domain. So I wanted to point out some recent examples.

As you may or may not know, there’s some real challenges to LTE roaming around the radio interface, such as the ability of a device to operate everywhere based on radio bands supported, other than that, nearly all other big issues are primarily in the business domain if you exclude VoLTE for the moment.  I thought it would be interesting to have a look at some of the public info out there regarding LTE roaming.

Firstly, why LTE roaming? Simple, there are LTE subs nearly everywhere now. Chart above shows something like 100M now. Unlike 3G with the different flavors, this is interesting because multiple (or greater number of) networks could potentially host foreign subs in a given location and since the subs are substantially on a single standard, a greater number to deal with.

As you can probably guess, there are 3 domains the situation exists in. Firstly is from the network standards point of view. 3GPP and others have been working on filling in the gaps to help the situation. Release 9 and 10 fix some roaming holes in the standard (actually just standardized the fixes) and go a long way. Beow Sybase has a network diagram for your viewing pleasure. You may recognize that Diameter is a key protocol between the networks and it’s relatively new into the marketplace. Verizon and others are still discovering the ins and outs of using it. 

Next up is the obligatory network diagram that shows at a glance the network topology of the roaming signaling situation.

The second domain is the network OEM perspective. There are several players in this space like Sybase, Diametriq, and Syniverse to name a few. They offer products to assist with the roaming infrastructure and or provide hosting services to enable it. 

For example, here is an interesting slide deck describing a Diameter Signaling Controller from Diametriq. Notice the comments about operator challenges and the complexity just within the diameter protocol universe.

And Syniverse announces hosted Diameter services…

Syniverse Solutions Ready SmarTone for LTE Interoperability 

Here is Syniverse’s deck that’s fairly interesting titled, Preparing for LTE Roaming

Outside of that there is 3G roaming that already has lots of glue in place. It gets complicated when considering that LTE networks can communicate much easier over the wire to each other, however using a completely different protocol set and network topology than what is in place, yet the 3G fallback is highly desirable (Voice or edge data coverage.

Some service providers like Global Telecom have taken the initiative to be a first mover in this area. 

Globe beats rival telcos with LTE roaming function

Ultimately having some service providers go first will help to accelerate the LTE roaming marketplace in general.

The final domain of LTE roaming challenge belongs to the UE. The recently launched iPhone5 and iPads do have LTE, which will increase demand based on their historical popularity, however these devices are based on Qualcomm RTR8600 technology limitations that do not facilitate a single chipset for all bands, therefore there are different models that can use different sets of spectrum. Sysbase’s William Dudley recently posted about the iPhone5 and roaming in:

iPhone 5: A Catalyst for LTE Roaming?

Smith Micro Software is offering something in this space, a mobile based solution that focuses the smartphone on using WiFi to offload and presumably avoid roaming over LTE.

To me, until there is a simple solution that allows a single device to utilize all LTE bands being deployed this is the biggest hurdle for LTE roaming to become widespread. However, when it finally does happen, the commercial possibilities are exciting as the increased competition will improve choice and pricing globally thus fueling more adoption perhaps in the Machine to Machine (M2M) space where we will be able to have all of our cars, homes and non phone type gadgets LTE enabled.
Just an observation.

Full Syniverse PR below…

Read Full Article →

 I admit, I’m slightly geeky, this seems like Friday fun to me, and more interesting than watching NASCAR but to each their own…Someone at Ericsson woke up on the good side of the bed the other day. The key points to me were 19Mbps @ 435Mph, from a jet. That’s a good day to be an RF guy. I get a kick out of these things…

BTW, I doubt this is truly the first test, many of you don’t turn your electronics off in the airplanes since we hear them ringing at 10K feet. Busted!

Geeky LTE salaciousness:

The Doppler effect, which limits how fast the user can move in a straight line to or from the LTE radio base station, was successfully tested and internet connectivity was maintained while flying at more than 600km/h in a straight line toward the LTE radio base station. A seamless handover from one radio base station to the next was possible while flying at a speed of 500km/h, without any visible disturbances to a video stream used to monitor the stability of the internet connection.

Enjoy the show!

Ericsson’s PR the other day said

What happens with an internet connection via LTE/4G on board of a jet plane flying 700km/h? Ericsson’s tests reveal that 4G is robust enough to handle extreme situations.

4G is the fastest developing system in the history of mobile communication. Today’s LTE networks are capable of providing speeds of over 100Mbps.

Consumers in high-speed trains around the world need reliable 4G connections without any interruptions and Ericsson needs to make sure its network equipment supports this requirement. This was the inspiration for tests that went above and beyond anything Ericsson has done before.

“We tested a high-speed 4G connection using an aircraft flying fast at low altitude.”, said Ola Melander, Master Project Manager for R&D at Ericsson.

“We continuously evaluate our systems and this was a good opportunity to test a 4G network in Sweden. The commercial network used for the tests was not altered for extreme mobility testing. Our radio and core network products proved to be robust and it was very interesting to see how well these performed.”

For the tests, a routine flight with a training jet from Saab Aeronautics carrying two Ericsson engineers with PCs fitted with LTE dongles, took off in Linköping, Sweden. While flying over Västervik at 300 meters above ground, measurements were taken to determine the impact of the Doppler effect, handover performance and video stream stability.

The results showed that the PCs were able to connect to the internet with a maximum downlink speed of 19 megabits per second while flying at 700km/h and with the force of 4G.

The Doppler effect, which limits how fast the user can move in a straight line to or from the LTE radio base station, was successfully tested and internet connectivity was maintained while flying at more than 600km/h in a straight line toward the LTE radio base station. A seamless handover from one radio base station to the next was possible while flying at a speed of 500km/h, without any visible disturbances to a video stream used to monitor the stability of the internet connection.

When the test was completed, there was a sense of achievement but preparations are already underway for further tests at even higher speeds. As the saying goes: The sky is the limit!

“We are very pleased with the results from this test,” says Per Narvinger, Head of Product Line LTE at Ericsson. “Ericsson’s standard radio and core network products were used in the network that was in commercial service and there were no problems to connect from the aircraft.”

About LTE

  • LTE is the global standard for the fourth generation of mobile broadband (4G), supported by all major players in the industry. It is the fastest developing system in the history of mobile communication.
  • Today’s LTE networks are able to provide speeds over 100Mbps. The technology allows for speeds in excess of 300Mbps and Ericsson demonstrated the next step of LTE at MWC 2010, with speeds up to 1.2Gbps
  • Currently 105 LTE operators has launched commercial services, 11 of these are LTE-TDD deployments and the rest is LTE-FDD. 299 operators have publicly committed to the technology across 93 different countries with a large number of LTE trials currently in operation.
  • In the first year of rollout 150 million people had access to LTE networks, and today 455 million people have access to commercial LTE networks.
  • Ericsson’s Traffic and Data report predicts that by 2017 half of the world’s population will be covered by LTE/4G networks. Smartphone subscriptions will number around three billion in 2017 – compared to 700 million in 2011.
  • Ericsson predicts that 85 percent of the world’s population will be covered by high-speed mobile internet in 2017 and mobile data traffic will increase 15-fold between 2011 and 2017.

Ericsson is the world’s leading provider of communications technology and services. We are enabling the Networked Society with efficient real-time solutions that allow us all to study, work and live our lives more freely, in sustainable societies around the world.

Our offering comprises services, software and infrastructure within Information and Communications Technology for telecom operators and other industries. Today more than 40 percent of the world’s mobile traffic goes through Ericsson networks and we support customers’ networks servicing more than 2.5 billion subscribers.

We operate in 180 countries and employ more than 100,000 people. Founded in 1876, Ericsson is headquartered in Stockholm, Sweden. In 2011 the company’s net sales were SEK 226.9 billion (USD 35.0 billion). Ericsson is listed on NASDAQ OMX, Stockholm and NASDAQ, New York stock exchanges.

 Again, This seems more interesting than watching NASCAR but to each their own… NASCAR fans, that was HANDOVER not HANGOVER.

Happy Friday

 I was looking at the Press Releases from US Cellular regarding their LTE market launches. You can see them here. Anyway the key things to me were, firstly the where…. 

The November rollout expands the 4G LTE footprint in select cities in Iowa, Wisconsin, North Carolina and Oklahoma, and brings 4G LTE coverage to some of U.S. Cellular’s leading markets in Illinois, Maryland, Missouri, New Hampshire, Vermont, Virginia and West Virginia. The next wave of market launches will follow shortly in Rockford, Ill., Medford, Ore., Yakima, Wash., and Knoxville, Tenn.

And this…the how…

King Street Wireless, L.P. currently holds 700 MHz wireless spectrum in 27 states and is partnering with Chicago-based U.S. Cellular to deliver high-speed 4G LTE service to U.S. Cellular’s customers in several of the carrier’s markets

So I was looking at some of these areas, and yes, there are Channel 51 DTV interferers in some of the same areas.

 Random pick, how about West Virginia? 

power | 15 kW  (kilowatts)  (effective radiated power)
height above average terrain | 0 feet
height above ground level | 187 feet
height above mean sea level | 1106 feet
directionality | directional

As you will note from the chart, there is a 15KW transmitter at Channel 51, so huge interference with the lower 700MHz UEs…  So looking a little closer at the spectrum ownership, they have a B channel/block in that market. So all this wind up to say:

1) Kudos to US Cellular for deploying lower 700MHz LTE

2) Unlike what Qualcomm was trying to convey in their report to the FCC, US Cellular is using the lower 700MHz Channel B without issue, probably some sharp eNB filters are helping out.

 It’s time for the rest of the market to jump in and play here. 700MHz LTE is a game changer based on the rich variety of spectrum owners and owing to the physics that the propagation of 700MHz channel is great compared to the typical 1900MHz or 2100MHz channels used for 3G. 

Keep up the good work US Cellular.

 Oh yeah, they have a cute video too. Check it out. :)



Voice over LTE (VoLTE) is the next big thing. In fact, in 24 months, virtually all LTE enabled smart phones will support it. Curious?
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