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Tag Archives: Carrier Aggregation

Opinion: New Uplink Testbed 5G Speed Record (Yawn)

By Ernest Worthman

Every time some vendors put together an ideal condition, very well crafted 5G data link that hits some new speed record, the data is jumped on by the media like the discovery of a new black hole.

Then, a gaggle of journalists call a gaggle of analysts and company PR people to analyze the event as if it really means something. News flash; it does not. Why? Because it is not real-world and only presents a transmission event that is finely tweaked with proprietary hardware in an isolated test. At best it is a glimpse of how well current equipment can perform.

One thing it does is impart the state-of-the-art under ideal and test conditions. That is all good and well, but it is hardly worth more than a few sentences in the news sections.

The most recent one came in a release from Ericsson and MediaTek where they combined both mmWave and carrier aggregation to achieve, combined, nearly a 500 Mbps uplink. What makes this noteworthy is that, traditionally, uplink speeds in wireless networks have been dismal.

Let us back up a moment and drill down on this a bit. Traditionally, bandwidth allocation has been asymmetrical. Uplink speeds have been sacrifice on the download alter – typically 10 percent or less of the download speed. And, for most consumer use cases it did not matter that much because most consumers download way more than the upload, anyway. The enterprise is another story, and its use cases are quite different.

That has been changing over the last few years because the consumer has been catching on to doing things that require more bandwidth. An example of that is creating and uploading their own music and video creations. Online gaming is another use case and social media back and forth is also starting to gobble up more bandwidth. Therefore, the demand for wider upload pipes has been increasing. And with it comes new ways to enable greater bandwidth, both symmetrical and, going forward, dynamic.

What all this is pointing to is that next-generation wireless networks will require a different approach to data flowing around.

Back to this test. This is an example of using both mmWave and LTE (of course, that is the definition in carrier aggregation in 5G). The mmWave part used 5G NSA, which is typical but uses proprietary equipment. The LTE is the standard 1900 MHz we all know and love.

The heavy lifting, of course, was done by the mmWave component at 39 GHz. Of the 495 Mbps, it hauled 425 Mbps. LTE handled the rest. The interesting part is that this test is comprised of aggregated carriers. There were four, 100-megahertz component carriers combined with one, 20-MHz channel of the LTE spectrum. Combined, they hit the 495 Mbps record.

The claim is that it “doubled the current uplink speed on the market.”  OK, but, the truth be told, the current uplink speeds, in most cases, are not even close to 250 Mbps (see the data from Opensignal further on).

The star of the show is the mmWave spectrum. Of the 420 MHz of bandwidth, 400 MHz handled 425 Mbps of the 495 Mbps. What I am getting at is that while throwing a 20 MHz channel at it to show carrier aggregation between 4G and 5G is not earth-shattering it is more to show that it works. In reality, the 4G channel is relatively insignificant.

Now, if the test used 400 MHz of mmWave and say, four or five 20 MHz LTE channels and following the logic, be closer to 700 Mbps, I would be more impressed. And do not forget this was over a5G NSA setup.

One can do carrier aggregation with both 4G and 5G all day long and get proportional results based on how much mmWave and how much LTE is aggregated. So, now we know that both mmWave and LTE can be combined (we knew that already) and the latest test simply showcases one particular configuration and what can be achieved.

The idea does have significance, however, because the uplink channel is becoming a major consideration in the evolution of networks. The pandemic is a classic case of how uplink bandwidth is becoming more important (as with the applications mentioned earlier) As well, expanded use of other applications, such as video conferencing, and online learning are ratcheting up.

Currently, upload speeds are dismal. Our friends at Opensignal, who seem to be the guardians of bandwidth metrics, just released a report of average upload speeds. The results were fairly consistent among the major carriers – between 30 and 40 Mbps (not 250 Mbps as Ericsson claimed).

This is also not going to go over well for things like sportingf events, concerts, and such where attendees are streaming videos of the content to others. Multiply that by a venue full of this type of streaming and things will get dicey. Users expect high-quality streams, which eat up bandwidth and frankly, sub-6 GHz frequencies are going to have a hard time providing sufficient bandwidth to meet these high-definition requirements.

Ericsson put a lot of emphasis on the carrier aggregation component. That is just being used to show carrier aggregation works (but we knew that already). This is not a particularly earth-shattering event.

The real excitement behind this will be the deployment of 5G mmWave, with or without carrier aggregation. Sub-6 GHz spectrum will not likely play a large part in this. What it will be good for is to manage those higher frequencies within the network. As I said, mmWave will do the heavy lifting.

The nice thing about this is that it puts a spotlight on a nagging issue that has to be addressed. While download speeds will continue to be the primary driver for bandwidth upload speeds will have to be sufficient to meet the rising demand that is emerging. The trick will be to juggle the bandwidth between up and download demand. This could be a prime case for network slicing. The key will be to do this dynamically.

Incidentally, when one looks at the raw numbers, each mmWave channel carried just over 106 Mbps. The LTE channel, 70 Mbps. To me, a 100 MHz channel carrying only about 33 percent more data than a 20 MHz channel has me questioning the technology here, especially in the mmWave spectrum.

While this was just a show project, it does call attention to the lack of resources for uploading data. There will be several vectors that will push the upload bandwidth issue, so it is good that the industry is starting to pay attention to it.


Ernest Worthman is an executive editor with AGL Media Group.

First End-to-end Band 48 CBRS Carrier Aggregation Demo

By The Editors of AGL

Verizon, Ericsson, Qualcomm Technologies and Federated Wireless have engaged in the first demonstration of LTE Advanced carrier aggregation over spectrum in the Band 48 — Citizens Broadband Radio Service band 48. The news follows Qualcomm, Ericsson and Verizon successfully surpassing 1 gigabit LTE speeds.

The CBRS band is made up of 150 MHz of 3.5 GHz shared spectrum which until now has been primarily used by the federal government for radar systems. The FCC has authorized shared use of the band with wireless small cells. Using the LTE Advanced feature of carrier aggregation, the wireless system carried LTE using carrier aggregation. Federated Wireless provided the Spectrum Access System to dynamically prioritize traffic within the FCC’s spectrum sharing framework for this band.

The demo, set in an Ericsson lab in Plano, TX included the end-to-end CBRS communication flow, using 2×20 megahertz LTE carriers on the CBRS band 48, and employing a 256 QAM modulation in the downlink.  Ericsson provided the band 48 Radio Dot System and Domain Proxy for communication with Federated SAS. Qualcomm Technologies provided a Qualcomm Snapdragon LTE modem test device, and Federated Wireless provided the spectrum management service with their Spectrum Controller.

LTE Lab Trial Sets Gigabit Speed Record

By The Editors of AGL

Verizon, Ericsson and Qualcomm Technologies continue to push the LTE speed envelope breaking the Gigabit speed barrier. The companies achieved an industry first with commercial silicon and network infrastructure with 1.07 Gbps download speeds using the Qualcomm Snapdragon X20 LTE Modem during an Ericsson lab trial.

This 1.07 Gbps achievement builds on Verizon’s recent announcement about Gigabit LTE with support for License Assisted Access (LAA). Also of significance, the 1.07 Gbps speed was achieved using only three 20 megahertz carriers of (Frequency Division Duplex using separate transmit and receive frequencies) spectrum, achieving new levels of spectral efficiency for commercial networks and devices. These efficiencies will enable the delivery of the Gigabit class experience to more customers and lead to new wireless innovations.

The companies achieved the 1.07 Gbps industry milestone by using 12 simultaneous LTE streams, which allow for up to 20 percent increase in peak data rates and capacity with a corresponding improvement in average speeds. Ericsson’s Radio System and LTE software, in concert with a mobile test device based on the Snapdragon X20 LTE modem, enabled these high speeds.

The lab tests also used 4×4 MIMO per carrier, 256 QAM per carrier, which enables customer devices and the network to exchange information in large amounts, delivering more bits of data in each transmission.


Carrier Aggregation Gains Some Momentum

By Ernest Worthman —

September 9, 2015 — It seems carrier aggregation (CA) technology is coming along. Just recently, Nokia Networks and Nordic mobile operator TeliaSonera conducted a live demonstration, in Finland, of LTE-A three-band carrier aggregation with Category nine devices. The companies claim the demo reached data rates of up to 375 Mbps using a commercial network.

The end-to-end demo, aggregated three LTE FDD carriers, two 20 megahertz, and one 10 megahertz. There are now plans to continue rolling out the advanced mobile service network-wide once compatible mobile devices, in sufficient volumes, become available.

It was a great integration of next-generation products, including Nokia Networks’ Single RAN Advanced platform, and a Flexi Multiradio 10 Base Station. The two 20-megahertz carriers were in the 1800 MHz and 2600 MHz bands, while the 10-megahertz carrier was in the 800 MHz band.

If this holds water, customers will benefit from superfast multimedia applications, and services once the technology is rolled out commercially.

T-Mobile Aggressively Moving on Multiple Fronts

By J. Sharpe Smith–

All eyes may be on the possible merger of T-Mobile and Sprint, but T-Mobile appears to be keeping its eye on something equally if not more important: improving its network.

As its network data use increased more than six times in the past two years, the carrier has advanced its LTE footprint to 230 million pops. At the same time, it has expanded wideband LTE — 15 megahertz by 15 megahertz — to 16 markets.

The carrier has now rolled out voice over LTE (VoLTE) in 15 markets covering more than 107 million people with the expectation to go nationwide by the end of this year.

“Because our network has been designed for data, we’re now able to nearly double the data that supports voice calls for superior, crystal-clear HD Voice,” said CTO Neville Ray in a blog post. “In fact, we offer the highest-fidelity HD Voice possible — 23.85 Kbps voice codec rate. VoLTE also offers faster call setup times than a non-VoLTE call, and customers are able to access our LTE network during a voice call.”

VoLTE, which debuted in Seattle last month, can now be found in Atlanta; Austin, Texas; Boston; Chicago; Dallas; Houston; Long Island, New York; Los Angeles; Minneapolis; New Jersey; New York; Philadelphia; San Francisco; Seattle; and Washington, D.C.

This technology rollout is reportedly being funded by the breakup fee that T-Mobile received after the AT&T merger failed. Observers note that the $2 billion breakup fee that would be paid in the event of a failed Sprint/ T-Mobile merger might pay for the next round of LTE rollouts.