HetNets: paving the way for “ultraband” age

Over time, telecom operators will provide consumers with a “universal connectivity” service (to rule them all), incorporating Wi-Fi and mobile broadband as a single resource, in an “always best connected” mode, leading to an ultraband connectivity service.
"Ultimately one should envision a not so distant future where there will be a mix of macro mobile networks, complemented by tens of millions of small cells and publicly available/shareable Wi-Fi hotspots," Ashraf says.
"Ultimately one should envision a not so distant future where there will be a mix of macro mobile networks, complemented by tens of millions of small cells and publicly available/shareable Wi-Fi hotspots," Ashraf says.
Ashraf: "LTE-U and LAA-LTE aim at enabling LTE to run over unlicensed bands, where LTE would use the 5Ghz WiFi band."
Ashraf: "LTE-U and LAA-LTE aim at enabling LTE to run over unlicensed bands, where LTE would use the 5Ghz WiFi band."
Ashraf: "Not only SONs will be able to provide greater and more consistent flow rates over the same mobile connection, but it will also enable mobile operators better manage HetNets."
Ashraf: "Not only SONs will be able to provide greater and more consistent flow rates over the same mobile connection, but it will also enable mobile operators better manage HetNets."

Share

By Tariq Ashraf

In 2010, the telecoms dividing lines were quite clear: on the one hand, there was a “canon” telecoms universe with a specific framework and associated set of rules, technologies and regulation, on the other there was a “non-canon” and “non-telecoms” universe with a perceived hodgepodge of technologies and (lack of) rules and regulation.

- The telecoms universe was made of access technologies such as xDSL and fibre for fixed broadband service, and 3GPP standards-bound technologies for mobile access   such as 3G, 4G.

- The non-telecoms universe was made of (DOCSIS) cable technology for fixed access, as well as WiMAX and Wi-Fi for nomadic services.

For telecom companies, those universes and technologies were not made to be mixed, much like matter and antimatter.

Worlds colliding…

Lately the situation has changed quite substantially due to technology maturing, and above all, strategic and business rationale:

- On the fixed broadband front, telecom operators have embraced cable technology, mostly via M&A as cable operators are very high broadband incumbent players.

- On the mobile front, the situation is of a mixed kind: WiMAX has lost the very high broadband war to LTE, while a handful of emerging countries’ operators have embraced the technology for fixed-wireless access.

- As far as Wi-Fi is concerned, the situation is a bit more “complicated”:  there always has been a Wi-Fi world, covering home or office broadband connections, public hotspots; and a mobile world, dedicated for “mobility” scenarios (Wi-Fi being labelled as “nomadic”).

Since the beginning of times, Wi-Fi has been in “frenemy” territory (at best) for mobile operators: when broadband customers become increasingly reliant on Wi-Fi hotspots availability, they would opt for lower mobile data “bucket” plans, or opt not to buy mobile-enabled tablets or other connected devices.

The fundamental problem lies in the licensed/unlicensed nature of mobile and Wi-Fi technologies. In most countries, one can operate Wi-Fi service without the need for a dedicated license (with no strings attached to the quality of service level, as there is no “guaranteed QoS” on Wi-Fi network access), whereas mobile connectivity is not only subject to licenses, rules and regulations but also to the measurement of KPIs (and enforcement) by local regulators.

As a result, not only the number of telecoms operators venturing in Wi-Fi space has been scarce, but also the ones who have been doing so, have been handling Wi-Fi as a mere “hobby”.

Cable operators driving the Wi-Fi momentum

Yet thanks to “non-telecom” players, Wi-Fi has gained momentum and has grown to become a service of its own. Cable operators envision Wi-Fi connectivity as a way to monetise ‘idle’ fixed bandwidth: US cable operators are currently ramping up Wi-Fi coverage because they have the capacity to do so and can provide such a service at a reasonable cost.

Mobile operators on their end are facing unparalleled data growth impacting their networks, resulting in financial and technical challenges:

- Data-driven consumer behaviour such as video streaming does put stress on network infrastructure not only due to amount of data but also because of tight latency requirements.

- As a result, the complexity to plan and manage network resources in order to achieve a first-rate subscriber experience, where delay-tolerant data services co-exist with real-time delay-intolerant voice and video services has heightened.

This is the very reason why telecom operators are looking at Wi-Fi again. One can provide carrier grade Wi-Fi as a standalone connectivity service, yet can also provide relief for networks that are overwhelmed by mobile data traffic via carrier-driven Wi-Fi offload. Moving a user off the network might seem counterintuitive, but does make sense in the current telecom cost environment as it could lower the connection cost for telecomsoperators, as Wi-Fi networks’ operating cost structure is very similar to fixed networks, and way lower than mobile RAN.

Several tier-1 telecomsoperators (especially in the US) have launched Wi-Fi offload initiatives, either leveraging their own Wi-Fi footprint, or/and connecting roaming hubs (such as iPass and Boingo Wireless that have launched connectivity “marketplaces”).

Wi-Fi offload: a first step to a pervasive “hybrid” connectivity

This process is already underway, via the Hotspot 2.0 technology that     enables secure and automatic authentication, policy management and seamless roaming on Wi-Fi networks.

Such an approach would help reduce cost for telecom operators, as they would be able to offload data traffic and reduce costly mobile network congestion.

Being fair, one could argue that both Wi-Fi and mobile technologies have their own merits and use-cases:

- Wi-Fi’s great strength is that it runs in unlicensed spectrum, can be deployed by anyone, providing high capacity, high-density indoor applications with low mobility.

- In contrast, mobile technology, which has swept across the globe over the last few decades, is ideal for its ubiquitous outdoor coverage, seamless mobility, and support for real-time applications like voice and streaming multimedia.

That’s the reason why the telecoms industry has been thinking about blending the two: combining these technologies offers great promise for the industry which could get the best of both worlds offering the best   quality of service through LTE signalling, with lower costs through the use of Wi-Fi spectrum.

Once again telecom and non-telecom worlds collide, as two different approaches are vying for the mobile and Wi-Fi amalgamation crown or heterogeneous networks (HetNets):

- LTE Unlicensed (LTE-U)/Licence Assisted Access LTE (LAA-LTE)

- LTE + Wi-Fi link aggregation (LWA)

Mobile over unlicensed spectrum (LTE-U and LAA-LTE)

LTE-U and LAA-LTE (Licence assisted access) aim at enabling LTE to run over unlicensed bands, . where LTE would use the Wi-Fi 5 GHz band. (whence the “ridesharing metaphor”).

The purpose of the unlicensed bands is to provide additional data plane performance. The biggest challenge with this approach revolves around getting LTE to coexist with Wi-Fi in the unlicensed bands, yet spectrum sharing is not part of the LTE DNA, indeed LTE assumes that it has full control over the frequency bands in which it operates and was never really designed to compete for access to the medium, unlike Wi-Fi, which is a first-come, first-served contention-based access model (listen-before-talk approach).

As a result, the Wi-Fi Alliance worries that that telecom operators will have an edge in the unlicensed bands because their networks are centrally managed, whereas Wi-Fi networks, on the other hand, tend to be a patchwork of access points and routers all operating independently but managing to cooperate. Introducing a centrally controlled and scheduled LAA network into that mix could mess up this “fragile” equilibrium.

LTE + Wi-Fi link aggregation (LWA)

An alternative to using LTE in unlicensed spectrum that could be much more palatable to the mobile industry is LTE + Wi-Fi Link Aggregation (LWA). This approach seems more “canon”: with LWA, the LTE data payload is split and part of the traffic is tunnelled over Wi-Fi and the rest is sent natively over LTE.  This can significantly enhance the performance of an LTE service. The approach is quite similar to LTE-Advanced and carrier aggregation.

With LWA, Wi-Fi runs in the unlicensed bands and LTE runs in the licensed bands, and the two radio technologies are combined to offer a compelling user experience. Both technologies are allowed to do what they do best, and LTE remains true to its design, as it no longer needs to behave like Wi-Fi when using unlicensed spectrum.

Additionally, unlike the deployment of LTE in unlicensed spectrum, which requires all new network hardware and all new smartphones, LWA can be enabled with a straightforward software upgrade allowing smartphones to power-up both radios and split the data plane traffic between LTE and Wi-Fi.

Ultraband is coming

Yet in order to make the most of Wi-Fi offload, telecom operators need to assess which users must/can be moved to Wi-Fi, what their quality of experience is, and what applications they are using: operators will want to give users the best possible connection in every situation (“always best-connected” approach), and in order to do this they will need clear visibility into both networks, integrating Wi-Fi with the mobile core.

This is where self-organising networks (SONs) kick in: not only SONs will be able to provide greater and more consistent flow rates over the same mobile connection, but it will also enable mobile operators better manage HetNets, routing clients either over Wi-Fi, over mobile technology or over both, and aiming at managing the overall HetNet at peak efficiency.

SON technology aims at automating network management and focuses at identifying situations where a base station capacity is not being utilised to its fullest, upon doing so, the network does trigger (automated) correcting measures, providing either mobile access (LTE), hybrid access (LTE + Wi-Fi) or Wi-Fi.

Such an approach would enable telecom operators to truly   benefit from the best of both worlds, improving telecom operators’ cost position and network performance. LWA is a way to increase not only spectral efficiency but capacity as well, while being integrated within mobile operators’ networks.

Ultimately one should envision a not so distant future where there will be a mix of macro mobile networks, complemented by tens of millions of small cells and publicly available/shareable Wi-Fi hotspots.

Over time, telecom operators will provide consumers with a “universal connectivity” service (to rule them all), incorporating Wi-Fi and mobile broadband as a single resource, in an “always best connected” mode, leading to an ultraband connectivity service. This connectivity will be built on a more dynamic relationship between the macro mobile network and the “smaller cell” network, which will be also critical to the next phase of connected development, powering (whatever the LPWA technology, Wi-Fi, LoRA, Narrow-band LTE…) the “Internet of Things” revolution.

About the author: Tariq Ashraf is a telecoms strategy and marketing expert. Tariq has a 14+ year-long strategy and marketing experience working with tier-1 telecoms operators covering both corporate and business strategy in Europe, North America, North Africa and the GCC region. 

Editor's Choice

Get smart
Telcos will be the backbone of smart cities, now it is up to them to innovate and collaborate to overcome the challenges of the market.
The complexities of regulating 5G
To build a 5G-based digital economy in the Middle East, the regulatory framework must include all of the stakeholders, from government to telcos, and a range of company verticals.
Why Identity Verification matters for mobile operators
How can mobile network operators really verify their subscribers’ identities and prevent identity fraud?

Most popular

Don't Miss a Story