Looking at Paul Jobs' (“Steve”) latest impressive product presentation (iPad) and Apple's success story with the iPhone, we are about to conclude that we finally have got the devices we are looking for in a mobile multimedia environment.
But honestly, does the infrastructure (in particular the mobile cellular network) provide an appropriate “road” to drive really fast with these new “cars”? The marketing answer is clear: yes, use 4G technologies, no speed limits any more...
Watch out! We all remember our experience with 3G. Is history just repeating? Is the “Next G” a real differentiator or just another buzzword? At least, some caution has to be applied. It starts with just the wording: if you ask a couple of people what the difference between 3G and 4G is, you may well not get a single answer. It depends on whether you ask people who want to sell something or the engineer who has to make it happen under technical and financial constraints. So, let's briefly talk about the wording, the (true) performance to be expected and the promising candidates.
Clearly, a next-G experience has to be seen from the user side (it's the same story as with the devices themselves). Talking about data rates only does not really present a value because in the majority of cases people don't even know what data rates they are talking about. Protagonists generally come along with the optimum value (eg, the maximum gross value an air interface can support, or the peak data rate of a radio cell with a single user in it), in reality (net performance of the air interface, certain traffic load in a cell, a cellular topology with interference, etc) the felt user experience is far below such expectations.
Not astonishing that we read the same if we follow the first reported experiences with 4G deployments. Consequently, the effective data rate a user sees under realistic deployment and load conditions is the more precise metric because that directly maps into his experience with a specific device. If we take this as a guideline, a next-generation experience might well be a user perception that is improved by one order of magnitude, in more blurry words: we need the “wow” effect. Of course, there are more ingredients of a true 4G package such as flat network architectures, low latency and so on but this is a different story.
As a consequence, it isn't so much a question of what individual technology might be a suitable candidate, it's more about what solution can provide the new user experience mentioned above. Due to the fact that within the generations (2G, 3G, 4G) there are smoother evolution steps, a well-engineered 3.5G solution might outperform something that is commonly referred to as 4G (4G classification given by the fact that just a new air interface technology is used). So, let's talk about the necessary main ingredients for a generation change and an improved user perception.
Dealing with scarce resources is the price we have to pay for mobility. Suitable frequency bands are limited and we need to go to the technical limits in particular if it comes to spectrum efficiency. Without going into details, we see two main areas today where we are able to squeeze the maximum out of a small piece of spectrum: adaptive technologies (eg, higher order modulation and coding) and spatial filtering technologies (eg, MIMO: Multiple In Multiple Out and/or AAS: Advanced Antenna Systems). All current standards supporting these advanced features consequently are supposed to be 4G candidates, in particular W-CDMA (UMTS +) and OFDM (WiMax and LTE). It can be shown that they are behaving quite similar under the same boundary conditions. But in practice, we often see quite diverging statements. There are two simple reasons for that: different RF bandwidths and adaptive behaviour. So, in comparing LTE with - say - UMTS+, we need to do this on an equal scale of RF bandwidth. Looking at adaptivity, we have to accept in both cases that the difference between best (“up to” philosophy) and worst (minimum guaranteed) case can be substantial. Promoting performance figures without mentioning the specific boundary conditions therefore is quite useless.
As a consequence: 4G is no magic at all. Definitely it isn't the magic knob that removes all problems. The old rules still apply: understand the principles and constraints of the technology basis, apply proper system engineering and rollout strategies aligned with marketing promises. Then Steve's new devices will like the network they are connected to.
Dr Hans-Peter Petry will be presenting about WiMax and LTE during the 5th annual Broadband Summit 2010 in Johannesburg on 30 March. For further reading, please refer to:
http://www.detecon-dmr.com/en/
http://www.detecon.com/en/publications/studies/studies_detail.html?unique_id=41571
http://www.detecon.com/en/publications/studies/studies_detail.html?unique_id=41570
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Detecon
Detecon is a consulting company which unites classic management consulting with a high level of technology expertise.
Our services focus on consulting and implementation solutions which are derived from the use of information and communications technology (ICT). All around the globe, clients from virtually all industries profit from our holistic know-how in questions of strategy and organisational design and in the use and implementation of state-of-the-art technologies.
Detecon's know-how bundles the knowledge from the successful conclusion of management and ICT projects in more than 160 countries. We are represented globally by subsidiaries, affiliates, and project offices.
Company contact details:
Dr Christoph Schetelich
Vice President Central and Southern Africa
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Dr. Hans-Peter Petry
Managing Partner and member of the executive board
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e-Mail: Hans-Peter.Petry@detecon.com