Each Next-Generation Mobile Network Since 2G Has Reduced Latency

As 5G core networks have shifted to a decomposed and virtual architecture, latency can become an issue, since functions can be performed remotely. But SKT and Intel say they have a way to reduce latency in virtualized 5G core networks substantially, by as much as 70 percent for transactions between the session management function (SMF) gateway and packet data unit (PDU) session microservices. 

The approach also enables a 33 percent reduction in gateway CPU usage, the firms say in a white paper. 

They believe the architecture will be useful for 6G, but the approach also works for 5G, illustrating the ways one mobile generation preps the way for the next, as key features and principles evolve. 

Mobile service providers would like nothing so much as a graceful evolution to “6G” performance, without disruptive changes to platform elements. Obviously, collaboration with device manufacturers, chip suppliers and other stakeholders will happen, to ensure device compatibility, standards alignment, and smooth integration of 6G technologies. 

But we should expect to see many other ways mobile operators will pursue an evolutionary 6G transition. As we have seen with 5G, existing spectrum will be leveraged, even if new spectrum allocations are made. 

Software-defined networks will facilitate network  upgrades that avoid hardware replacements. 

Network slicing might also be used to enable the coexistence of diverse 5G and 6G services on the same infrastructure.

We might also see efforts to conduct Incremental upgrades, where 6G features and functionalities are introduced in stages, in much the way that 4G voice services relied on 3G and 5G relies on 4G for voice. More advanced features, such as network slicing, might be introduced later than basic functions such as new frequency bands for capacity boosts, as happened with 5G. 

Why Orange Will Not Market "6G"

It is a bit of a subtlety, but Orange is not sure it will “market 6G,” which is not the same thing as saying it will not use 6G. Unless something very unusual happens, such as the global industry deciding it does not want creation of a “6G” standard, 6G is going to happen, for the simple reason that mobile operators will continue to need additional bandwidth and capacity, and 6G is going to be needed to accomplish that.

Aside from all other matters, 6G will mean regulators must authorize additional spectrum for the platform, and additional spectrum is among the main tools mobile operators have for increasing capacity on their networks. 

Nor does such a stance really mean that Orange will stop investing in the latest generations of mobile networks. It does mean Orange will deemphasize “generation” as personal computer makers have deemphasized “clock speed” as a value driver or differentiator. 

Mobile phone suppliers, meanwhile, once marketed “smartphones” based on screen size,  touchscreen interfaces rather than keypads and ability to use mobile internet and apps. 

These days, much more emphasis is placed on battery life and camera features. One can safely predict that artificial intelligence features will be the next marketing battleground. 

In similar fashion, personal computers once marketed their devices on “performance” and a few lead use cases (word processing or spreadsheets). So processor speed, storage and memory were key messages. 

Later, bundled apps, connectivity and user-friendly interfaces became more important. These days, mobility (weight, form factor), multi-function use or sustainability are more prominent messages. 

The point is that features once considered differentiators often lose their appeal as markets mature. 

ITU Releases Framework Document for 6G

The International Telecommunications Union has published some details of its framework for 6G  networks, and many of the objectives are what you’d expect. Compared to 5G, 6G will support higher speeds, lower latency, be more spectrally efficient, energy efficient, feature artificial intelligence and sensing. 

• Peak data rates of 50 Gbps, 100 Gbps or 200 Gbps

• User experienced data rates of 300 Mbps and 500 Mbps

• Spectrum efficiency 1.5 and 3 times greater than that of IMT-2020 (5G)

• Area traffic capacity of 30 Mbps/m2 and 50 Mbit/s/m2

• Connection Density could be 106 to 108 devices/km2

•  Mobility Maximum speed, at which a defined QoS and seamless transfer between radio nodes could be 500 – 1 000 km/h

• latency (over the air interface) could be 0.1 – 1 ms.

In addition to those quantitative metrics, there are the expected qualitative benefits. The framework document includes talk of ubiquitous computing, ubiquitous intelligence, immersive multimedia, digital twins, virtual worlds, smart industrial apps, digital health, ubiquitous connectivity and sensing integration.  

As with prior generations (3G, 4G, 5G), many of those qualitative outcomes might be delayed or available only in rudimentary form. 

There are good reasons why mobile operators are much more concerned about “application revenue” than home broadband providers. Mobile operators always are in the “applications” business, where home broadband providers are only in the “internet access” business. 

In other words, mobile operators derive significant revenue from their own voice and messaging applications. ISPs providing home broadband mostly make money from subscriptions providing the internet access function. Most of their other revenue is related to the access function, such as equipment rentals or install fees. 

Revenue Source	Home Broadband Network	Mobile Operator Revenue
Subscription Fees	70.00%	40.00%
Voice Services	0.00%	25.00%
Data Services	0.00%	20.00%
Equipment Rental Fees	10.00%	0.00%
Installation Fees	5.00%	0.00%
Roaming Fees	0.00%	5.00%
Other Revenue	15.00%	10.00%

Also, mobile operators are dependent on government regulators to authorize additional spectrum, so there is a political underpinning to arguing that additional spectrum will lead to public advantages beyond “faster speeds.”

Still, in large part, the success of  built-in “app capabilities” will likely be hard to predict. Since mobile network value includes a mix of “apps” (largely voice and messaging) and “internet access” (dumb pipe access), much--if not most--of the value comes from the “internet access” function. 

As for home broadband networks, faster speeds are a continual requirement, as are support for carrier voice and messaging. Beyond those essential functions, it always is difficult to say how much other value can be reaped directly by mobile operators in the “apps” space and beyond connectivity itself. 

6G might not be so different from earlier generations in that regard.

Problem: 5G Cost More than 4G; 6G Will Cost More than 5G

By some estimates, the cost of 4G and 5G networks has gotten more expensive, and 6G is expected to be more expensive than 6G. 

There are several reasons, including the cost of new spectrum; the need for greater numbers of small cells, each supported by optical fiber connectivity; the cost of more-complicated radios; perhaps higher-cost engineering and higher site acquisition costs. 

Technology	Cost per location	Cost per square mile
4G	$10,000-$50,000	$500,000-$2,500,000
5G	$25,000-$100,000	$1,250,000-$5,000,000
6G (estimated)	$50,000-$200,000	$2,500,000-$10,000,000

All of that drives mobile operator concern about the business model for 5G and 6G. Some of that concern is about revenue, but much of the issue is the ever-higher need for capacity. 

By general agreement, mobile operator capacity gains have historically been driven by use of smaller cells (network densification) and allocation of additional spectrum. But most observers would tend to agree that denser architectures have contributed the most. 

In addition to use of smaller cells and additional spectrum, Wi-Fi offload, better radio technologies and modulation techniques also have contributed. And the mix of contributors arguably has changed over time. For example, Wi-Fi offload was not a factor for 2G networks.

In the 4G and 5G era, Wi-Fi offload might represent as much as 75 percent of mobile device data (principally internet access), but rarely less than 45 percent of total mobile internet data. 

Country	Percentage of mobile phone traffic offloaded to Wi-Fi
United States	60%
China	70%
India	50%
Japan	65%
South Korea	75%
United Kingdom	55%
Germany	60%
France	50%
Brazil	45%
Russia	55%

As mobile executives resist the ever-growing amount of capital they must spend to increase capacity, data offload might be one of the most-fruitful ways to add effective capacity while containing capital investment, at least to a point.

6G Should "Enable," Not "Create" New Apps and Use Cases

After our experiences with 3G, 4G and now 5G, perhaps we ought to be more circumspect about all the positively amazing new experiences that will actually develop when we get to 6G. 

Already, observers offer examples of new applications and services that could be enabled by 6G:

• Real-time holographic video conferencing

• Augmented reality experiences

• Self-driving cars

• Remote surgery

• Mobile broadband in rural areas

• IoT connectivity in dense urban environments

None of that will startle: those were raised as apps that could be supported by 5G, and might yet emerge. 

And more to the point, despite the expected improvements in latency performance and bandwidth, maybe we should be cautious about claiming too much for the ways artificial intelligence or virtual reality will be embedded into the core network. 

No doubt AI will be used to support the core network and its processes. But that’s different from possible efforts to embed AI or AR or VR as customer-facing features of the networks, as some might propose. 

Beyond making the network operate as efficiently as possible, offering the best latency performance and bandwidth support we can reasonably develop in the next generation of networks, we might remain skeptical of efforts to claim or support network features that go beyond making the network as liquid as possible; as dynamic as possible; as flexible as possible. 

An energy-efficient network, using an on-demand architecture featuring low latency capabilities and no restrictions on bandwidth, using virtual mechanisms, is a reasonable goal. 

Beyond that, what we probably still need is a permissionless development environment, where app software does not have to assume much other than the existence of the low-latency, high-bandwidth connectivity. 

In other words, perhaps all we want is a network that is as open as possible, as virtualized as possible, as flexible and dynamic as possible, capable of supporting any conceivable application but without embedding any of that inside the core network. 

But some will try to create capabilities that are embedded into the core network, no doubt. That’s one way of attempting to profit from apps using the network.

Will 6G Try to Recreate Closed Networks?

Already, some are suggesting 6G will be different from 5G in a significant way: where 5G is still a connectivity mechanism, some tout 6G as a computing mechanism. It will “enable immersive, ubiquitous, and sensory digital experiences on a massive scale,” some argue. 

“Enable,” yes, in the same way that home broadband “enables” use of internet-delivered applications.  “Embed,” in the sense of the network itself being the supplier of the features, probably not, and for good reasons. 

Modern computing is based on layers. That is what allows us to innovate faster and avoid monolithic solutions because functions are compartmentalized; independent objects rather than integrated processes. 

Even if infrastructure suppliers want us to accept new forms of functions integration as a way of convincing us to buy their new platforms, we should resist the notion. We actually do want permissionless app creation, not “integrated” solutions. 

In other words, some are likely to argue for 6G standards that are more centralized and controlled than 5G networks. More “closed,” in other words. 

Some will argue this is necessary because 6G will need to support a wider range of complex and demanding applications, such as immersive virtual reality and real-time AI-powered services. 

We might want to resist that notion. It is a move in the direction of walled gardens, closed networks and app development controlled, to a larger extent, by the entities providing internet access. 

Is that going to be better? 

Some will argue for advantages such as enhanced security or privacy. But permissionless development enabled by the layered architecture  has worked well. It’s easy to see why some in the value chain would prefer more closed, centralized networks. 

It recreates the experience of the public switched telephone network, where telcos controlled “all” the apps running on the network. 

To use the network, you needed permission from the network operator. Is that going to be better?

Every mobile generation gets hyped. Each will, it is said, enable and revolutionize the experience. Improvements happen, yes. Latency is reduced; bandwidth is increased; energy efficiency gets better. 

6G should “enable” immersive experiences such as the metaverse by staying out of the way. Embedding such features into the fabric of the network--beyond measures to control latency and supply lots of bandwidth--will be a mistake.

How Feasible is a Software-Only 6G Upgrade to 5G?

If telco executives get their way, 6G will be a software upgrade that does not require replacement of 5G network elements such as radios. In some ways, that will be challenging. 

"We believe that a software-only upgrade to 6G is the best way to meet the increasing demands of mobile users and businesses,” said Niklas Heuveldop, Vodafone CTO. 

"A software-only upgrade to 6G is essential for us,” said Hannes Ametsreiter, Deutsche Telekom CTO.

Perhaps surprisingly, even Rajeev Suri, Nokia CEO, has said "a software-only upgrade to 6G is the only way to meet the ambitious goals of the 6G roadmap.” It will be challenging. 

It is not clear whether the in-place radios are frequency-agile enough to handle huge new blocks of millimeter wave or teraHertz frequencies. So it is not clear whether virtualized or software-defined radios can be used with the existing 5G infrastructure to allow the 6G upgrades without major upgrades or replacement of existing radio infrastructure. 

Then there is the issue of whether the existing 5G network radio sites are compatible with the signal propagation characteristics of new millimeter or teraHertz spectrum that might be added, or how much new radios or new small cell sites will be required. 

Easier to implement are new modulation techniques, for which there are a number of possible alternatives to the 5G orthogonal frequency-division multiplexing standard. 

What might make adaptive modulation possible--the ability to use different modulation methods depending on local conditions, is the 5G ability to support 5G networks can also use adaptive modulation, which allows the modulation scheme to be changed dynamically, depending on the channel conditions. 

That feature should support dynamic modulation that is more robust in areas where signal propagation is more challenging (though supporting less bandwidth); but supporting maximum throughput in other areas with favorable signal propagation characteristics.

6G is expected to use higher-order modulation schemes than 5G, such as 256QAM and 1024QAM. This will allow for more bits to be transmitted per symbol, increasing the spectral efficiency of the network. 

But there also are a number of potential modulation approaches. 

Index modulation: Index modulation is a technique that uses the indices of active transmit antennas, subcarriers, or time slots to transmit additional information. This can be used to further increase the spectral efficiency of the network.

Non-orthogonal multiple access (NOMA): NOMA is a technique that allows multiple users to share the same spectrum resources at the same time, without causing interference. This can be used to improve the network capacity and support more connected devices.

Machine learning (ML)-based modulation: ML can be used to develop new modulation schemes that are more efficient and robust to interference.

Hybrid modulation schemes: Hybrid modulation schemes combine elements of different modulation schemes to achieve the best possible performance in different operating conditions.

Polar modulation: Polar modulation is a new type of modulation that is more efficient and robust than conventional modulation schemes. Polar modulation is expected to be used in 6G to achieve higher data rates and improve reliability.

MIMO modulation: MIMO modulation uses multiple antennas to transmit and receive data simultaneously. This can significantly increase data rates and improve reliability. 6G is expected to use MIMO modulation with a larger number of antennas than previous generations of cellular technology.

MIMO-OFDM: MIMO-OFDM is a multiplexing technique that uses multiple antennas at the transmitter and receiver to transmit and receive multiple data streams simultaneously. MIMO-OFDM is already used in 5G networks. 

In addition to OFDM, 5G networks can also use other modulation techniques, such as filter bank multicarrier (FBMC) and universal filtered multicarrier (UFMC). However, OFDM is the most widely used modulation technique in 5G networks today.

It is the existing 5G network’s ability to use adaptive modulation, supporting modulation schemes that can be changed dynamically depending on the channel conditions, which will support 6G. 

It remains to be seen how much such approaches can support a software-only upgrade of 5G to support 6G. Many will guess that hardware upgrades will still be necessary, though on a perhaps-reduced level compared to earlier mobile network upgrades. 

That there is growing buyer resistance to the traditional hardware-based platform updates is obvious. Just as obviously, there are possible new opportunities for non-traditional suppliers, such as the hyperscale cloud computing providers.

"You Get to Keep Your Business" Will be the Fundamental Driver of 6G

Most 5G infra suppliers and mobile operators have been insistent that 5G would enable new use cases, novel applications and drive higher revenue, to some extent. So far, those proponents have been “wrong,” but only to the extent that they also were wrong about 3G and 4G. 

Though some important new use cases have emerged in each digital generation (from 2G on), most of the innovation has not been of the sort mobile operators can directly participate in as equity owners. 

In other words, most of the new value and revenue from new use cases has flowed to third-party app developers. And if you think about it, that is what is “supposed” to happen when a layered app architecture is assumed. 

By definition, the internet is “permissionless.” App creators do not require a formal business relationship with an internet access provider to reach users and customers. 

Eventually, some new 5G use cases will develop. But infra suppliers and mobile operators have routinely “over-promised and under-delivered” in the area of new apps, use cases and value, for every digital mobile generation.

An SKT white paper says 5F failed to achieve its goals, among which were the rapid development of new use cases, apps and services that collectively would fuel mobile operator revenue growth. There was no “killer service.”

SKT also essentially argues that 5G “over-promised and under-delivered.” Customers expected much more than what was delivered. 

As was the case for 4G, 6G will enable “services that were difficult to fully implement with 5G.” Anybody who followed 4G will get this. The promises of one mobile generation often are not realized--if at all--until the subsequent generation. 

In other words, some use cases hoped for in the 3G era did not develop until 4G. Perhaps some 4G use cases will flourish during 5G. Perhaps some 5G innovations will happen when 6G arrives. 

Maybe the industry is simply collectively wishful, without sufficient basis in fact. What a given network can do is not the same as assurance customers will value the innovations, or pay to use them. 

Quite to the contrary, the very architecture of internet-based apps and services militates against the ability of access providers to capture the value of app development. 

Perhaps a comparison with home broadband will illustrate why the “over-promising” always happens. Over time, home broadband has moved capacity upwards from kilobits per second to megabits to gigabits per second. As with mobile platforms, home broadband networks have used different media to support those advances. 

But nobody actually argues that “faster home broadband” will directly lead to new use cases and value supplied by the internet service provider. People understand that virtually all of the development will be fueled by third parties. The faster internet access only enables use of those innovations. 

Mobile operators might argue that they have a more-embedded role, as they offer managed services including voice and messaging. True, but some fixed network suppliers also offer voice, as well as internet access. 

The point is that a mobile service provider, in its role as an ISP, supplies “internet access” but not apps. And the primary value of 5G is that it supports more capacity than did 4G, as 4G enabled more capacity than 3G. 

Such capacity increases are essential. But ISPs are not primarily the producers of application value. 

To be sure, ISPs and their infra suppliers have to argue that wonderful new apps will be possible. Otherwise, it is hard to convince regulators to grant use of more spectrum. But everyone also understands that the new apps will mostly be produced by third parties. 

5G and 6G are vital, nonetheless. As with home broadband networks, capacity must continually be increased. 

But the hard truth is that 5G mostly means “you get to keep your business.” It is a means of supplying needed capacity, primarily. Someday, 6G will be required to enable mobile service providers to stay in business.

But the claimed benefits will extend quite a bit beyond that. They always do. 

Prosaic though it might be, the next-generation mobile networks are the functional equivalent of increasing home broadband and fixed network capacity from kilobits per second to megabits to gigabits. “More capacity” is the value. 

4G, 5G, 6G and beyond are the means by which mobile operators are able to supply faster speeds and more capacity over time. It means they get to stay in business. But it generally does not mean the mobile operators themselves will be creating new apps and use cases. 

So expect 6G to be yet another example of “failure.” Proponents will again over-promise. To get additional spectrum, they almost have to do so. 

But do not be fooled. They need more capacity. The way they will get it is partly by adopting 6G. It is important; they need to do so. But most of the hype about new value, apps and use cases--as produced by the mobile operators themselves--will fail. 

The architecture ensures it. The whole point of internet access is to enable people and machines to use apps available to internet-connected devices. We need more capacity, over time. New mobile networks are how we get there. 

But think of 5G and 6G as a necessary precondition for remaining in business, as faster fixed network access also is a fundamental requirement. Proponents will emphasize bells and whistles. Ignore all that. It is about remaining in business, as that business requires more capacity over time.