If 54-million people in Africa use 3G for data connectivity, 3-million people use ADSL and less than 500 000 people use satellite, does this mean 3G is the best option for broadband internet access services? 

Is the number of subscribers indicative of performance, marketing excellence or both?

When marketing messages, pricing policies and technology advantages are blurred, then it is rather difficult to differentiate the principles and what service will be best for a particular application.

Within this situation in which it seems that providers are actively collaborating to disguise the fundamentals, having our own reference of the fundamental principles will certainly help, says Dr Dawie de Wet, PhD Electronic Engineering, CEO, Q-KON.

This discussion provides a principle understanding to equip subscribers, managers and network architects with an appreciation of the intrinsic difference between these technologies.

It doesn’t provide a point-by-point comparison between the technologies – to do so would be counter to the main message of this discussion: that each technology is very different, each has a core focussed application area and are not really alternatives for one another.

To start the discussion let us consider some examples, hypothesises and paradigm-shifting thoughts.

DStv or Digital Satellite Television is vastly successful in Africa and implemented using satellite communications channels. North America’s television industry was established using cable TV networks and, given the rapid rollout of fibre networks in Africa, is it fair to assume that DStv will soon migrate to a cabled technology?

If fibre, as a cable technology, is faster and cheaper than satellite, why not migrate DStv to fibre networks? Yet, we haven’t heard any discussions that fibre networks could be considered as a means to broadcast DStv channels.

This is because satellite networks are ideal for broadcast services – services where the same content is distributed from a single point to many remote locations as applicable to television broadcast, digital media, educational content distribution and so on.

Once we understand this fundamental characteristic of satellite networks we will be able to make decisions based on solid references and not on specific product offerings.

Next, let us consider public broadband access networks or mobile data networks used by 6.4-million subscribers in South Africa as opposed to only 875 000 subscribers that use ADSL as a broadband access option.

Surely six-million users cannot be wrong! 3G must be the better option. In this case we define “better” from a user perspective meaning faster, cheaper and more reliable.

When we look at the specific pricing and compare 3G with ADSL, then 3G actually compares poorly to ADSL. Furthermore, mobile data networks are actually “best effort” services and not generally offered with a committed minimum service level. Taking this into consideration, 3G has lost the factual comparison, yet has the lead in market acceptance.

This is one example that effectively illustrates that mass deployment or mass acceptance of technology could be for the wrong reasons and not because the technology is fundamentally better.

Buying decisions are not based on pure technology criteria and, more often than not, influenced by some past experience, interaction with a specific service provider or general market perception (a more serious issue).

Business is an integrated domain of technology, relationships, service delivery, pricing and much more, and it would be futile to try to explain all these intricacies. Rather, we will focus on providing a general understanding of the principles of each of these technologies so that users and network architects can align technology principles with requirements and then add all the other considerations.

First we consider ADSL networks. South Africa and most countries across Africa operate on fixed line infrastructure that is provided by public network operators. The service is implemented using either copper cable networks, or in very limited areas, fibre distribution networks.

In South Africa the service is implemented over Telkom’s infrastructure and is defined in terms of the expected data rates with no further service level definition or commitment. ADSL can only be offered in areas with digital exchanges and also when the subscriber premises are within a limited range from digital exchanges.

ADSL services are implemented over point-to-point circuits from the customer premises, through Telkom’s network, to the data centre of head office. Even customer national networks are implemented using this “circuit” philosophy and comprise- of multiple integrated point-to-point links.

3G (or other mobile data) services, initially developed as a data connectivity solution for individual users, are offered using mobile network infrastructure and is available throughout South Africa. The phenomenal success of mobile network operators has resulted in this service being made effectively available “anytime and everywhere”.

The success of the 3G networks has also led to the use of 3G services for corporate data connectivity applications such as bank ATM networks, office connectivity, remote data collection and much more.

However, with the mass adaptation of 3G data connectivity services and the increase in GSM network traffic, network congestion has become more of a hindrance and limitation and more so because the “best effort” nature of this service is part of the principle technology characteristics.

Satellite networks (except for the latest Ka-band deployments) are available anywhere and anytime. These networks are developed with extreme high availability and reliability… ever wondered what would happen if the national television broadcast is done on a “best effort” basis?

Satellite networks are perfectly positioned for broadcast application and, remember, distribution of IP content is just another format of broadcasting (technically referred to as multicasting).

Whilst this is not an in-depth analysis of each technology, it does strive to communicate a better understanding of the satellite versus 3G versus ADSL to guide users and network architects.

The key technology differentiation points are summarised as follows:
* Satellite networks provide “anywhere and anytime” communication at extreme high availability and is perfect for broadcast applications, including data broadcast.
* ADSL and cables networks are the cost leaders for services to fixed locations within metropolitan areas and where available.
* 3G and mobile data services are the ultimate in convenience and ease of deployment yet limited by a “best-effort” service level commitment for enterprise applications.