Synonyms

Ultrafast broadband networks; Ultra-broadband networks

Sometimes the “access” is missing and the term is used simply as “next-generation networks (NGN),” although strictly speaking NGN would refer to the whole infrastructure and not only to the part closer – the access – to the final user.

Acronym

NGAN

Definition

Next-generation access networks refer to telecommunications infrastructures – and the technologies that support them – able to provide final customers with data rates above 30–50 Mbps.

Reference Framework: Broadband and Economic Development

The rise of the knowledge economy has reinforced the role of telecommunications as a strategic investment:

… the ability to communicate information at high speeds and through various platforms is key to the development of new goods and services. Broadband enables new applications and enhances the capacity of existing ones. It stimulates economic growth through the creation of new services and the opening up of new investment and jobs opportunities. But broadband also enhances the productivity of many existing processes, leading to better wages and better returns on investment. (EC 2006)

Next-Generation Networks and Next-Generation Access Networks

Next-generation networks (NGN) are the supporting infrastructure of ubiquitous broadband. They are defined as networks based on the Internet Protocol able to deliver multiple data applications – whether originally based on voice, data, and video – to multiple devices, whether fixed or mobile. In addition, the provision of applications is decoupled from networks facilitating the introduction of innovations (De-Antonio et al. 2006).

An NGN can be divided into two main parts (Knightson et al. 2005):

  • A backbone transport network that interconnects the local nodes where data traffic from the final users is gathered to be switched and further transported. The backhaul from distant nodes to the core network is typically included as part of the backbone, although it is convenient at times to consider it separately (the so-called middle-mile).

  • An access network that links final users with local nodes, the next-generation access network (NGAN), colloquially called the last-mile.

NGAN Requirements

There is nothing like a strict definition of the minimum access speeds provided by an NGAN or any other defining parameter. A tacit agreement at the industry level seems to put this figure at 50 Mbps or beyond, but to prove the vagueness of the case, there are no indications whether this number refers to both the upstream and downstream parts or it should be applied just to the downstream channel. Even less is mentioned about the quality of service-guaranteed data rates per customer. Also, while the above figure may represent as of May 2014 some consensus, there are a number of regulatory decisions and digital strategy plans that implicitly address figures from 30 Mbps to 100 Mbps; see the Digital Agenda Europe for 2020 as a main example. In any case, these figures are beyond conventional broadband capabilities and therefore the name of ultra-broadband networks.

Some sources provide a narrower definition in relation to NGN to include exclusively wired access networks which consist wholly or partly in optical elements and are capable of providing enhanced broadband access compared to services provided over existing copper networks. According to this type of definitions, wireless networks are not part of NGAN; see below.

NGAN Technologies

In general, broadband access technologies can be classified by the physical medium into two major groups: wired (or fixed line) technologies and wireless technologies. The main wired technologies are based on fiber, coaxial, copper wire (or any combination of them), and power line. Wireless technologies can be either satellite based or terrestrial. Terrestrial wireless solutions can be either fixed or mobile. Due to their niche market prospects and limitations, power line communications, satellite solutions – or other recently proposed airborne solutions such as balloons – and fixed wireless are not usually accounted among the NGAN technologies.

Therefore, the list of NGAN technologies as of 2014 reduces to:

  • Fiber to the home (FTTH). In this technology fiber runs all the way to the customer premises from the local node. FTTH technology is the ultimate fixed solution, supplying the highest data rates possible per household (Kramer et al. 2012).

  • Fiber to the basement/building/cabinet/curb/node/premises (FTTx). FTTx is a generic term for those technologies which bring fiber from the central office closer to the subscriber. They come in many varieties depending on the termination point of the optical network. In all of these architectures, the fiber from the central office is brought down to a node where equipment is housed in a cabinet to convert signals from the optical network (fiber) into electronic (copper wire, wireless connection, or even coaxial cable). The main advantage of these solutions is reusing part of the existing legacy network.

  • Digital Solutions on subscriber loop (xDSL). From the point of view of the architecture of the technology, xDSL solutions are equivalent to FTTx solutions mentioned above, their only difference being the perspective adopted: from the copper wire or from the fiber optics side. Among them VDSL is the most widely used technology over copper wire. With new technological developments able to increase data rates, copper lines will continue to be a strategic asset well into the midterm. Not only are they able to provide data rates that would fall into the NGAN category, but, in addition, they also allow for a smoother and more scalable path in the transition from existing broadband to FTTH.

  • Upgrade of cable television networks (DOCSIS). Typically cable networks use HFC (“hybrid fiber-coaxial”) technology. DOCSIS (“Data Over Cable Service Interface Specification”) is the name of the series of standards developed for high-speed data transmission over cable television networks with release 3.0, the most widespread as of 2014. In general it could be said that the role of cable networks is particularly relevant in the NGAN competition scenario as the only different infrastructure from those of historical telecoms operators.

  • 4th generation mobile communications (4G). The case of mobile wireless is controversial regarding its inclusion into NGAN. Mobile technologies are approximately 3–5 years behind fixed technologies in terms of sustained data rates per user. However, they already deliver peak data rates well above 100 Mbps, and they are not far from reaching the 10 Mbps level per user with some consistency. Therefore, mobile broadband connections are considered here as a suitable (stand-alone or complementary) technological alternative to fixed access technologies. The most relevant technology is LTE, labeled as 4G by the International Telecommunications Union in 2010 (Ghosh et al. 2010). 4G plays a fundamental role: not only is it the cheapest solution for rural areas, but it can also complement or even replace fixed broadband in urban and suburban areas, especially as wireless technologies fit mobile lifestyles better.

NGAN Deployment

The choice of access technology is simply a matter of deployment costs (which in turn depend basically on socio-demographics and geographic variables and possible reuse of existing infrastructures) and the user’s requirements (and expectations).

Regarding the status of deployment, in general terms it can be said that as of 2014 NGAN is still in a relatively early stage of deployment – particularly out of main urban areas. In any case, the transition from copper to fiber access networks is underway, and it is expected to result in the replacement of most copper access networks over the next two decades.

Future Directions

From a technical perspective, future prospects for NGAN include some form of fixed-mobile convergence, where fiber networks will be complemented by heterogeneous wireless networks (Raychaudhuri and Mandayam 2012). The rationale is that no access technology enjoys the optimal characteristics for satisfying all the requirements demanded by users in every circumstance. Therefore, this case is leading operators to create platforms capable of integrating different access technologies over the same backbone network. The future market of the ICT sector, characterized by “comprehensive” operators, would be quite different from the current one, where there is clear separation between technologies.

From an economic perspective, the conditions for the deployment of NGAN are currently on the forefront of the debate about the role of telecommunication markets, the best regulation for them, the conditions for the return on investments, the type and level of competition, the requirements for sustained innovation, and the level and modes of potential public involvement (Bauer 2010).

Cross-References