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RSS feedsBandwidth poses the greatest problem for 3G and other next-generation wireless technologies. Given present predictions for demand, it may be the case that there isn't enough to go around.
Only a fortnight ago we reported that the Radiocommunications Agency (RA) warned that the 2.4Ghz band, used for industrial, military and scientific applications, could become so populated with wireless devices that the whole frequency could collapse and crash.
What we need is something that can pick and choose the frequency, and radio access technology, to operate on and keep the lines of communication up and running.
Radio control
One such technology in the offing is software-defined radio (SDR). SDR is already used in the US at a primitive level in dual mode analog/digital mobile phones. It acts as a moderator between the two. The basic idea is that software will switch between technologies as the users move from one type of network to another or change networks when one becomes saturated with traffic.
Its proponents want to extend this functionality to integrate current radio technologies as well as those for 3G networks. This should culminate in better coverage and a seamless migration path to 3G and beyond.
It will also give both user and network provider the opportunity to get the bandwidth they need from whatever source, and be able to use high-speed data services without causing the network to become clogged, or cause an outage.
Until now, SDR has mainly been used by the US military to make it easier to exchange data in the field. It allows users to make optimum use of the access technologies at their disposal and automatically select the best system to access the data - rather like an A-to-Z map of shortcuts.
In SDR, functions that were originally carried out solely in hardware, such as the generation of the transmitted radio signal and the tuning of the received radio signal, are performed by software in powerful digital signal processors.
And because these functions are executed in software, the radio can be programmed to receive and transmit signals over a wide range of frequencies.
Additionally, it can emulate virtually any desired transmission format - changing the software alters the radio's effective parameters.
In the next few years a number of technologies will be working in parallel, such as GSM, GPRS, Bluetooth, 3G, wireless local area networks and infrared. This scenario will make automatic optimisation and selection an absolute necessity for their users.
It also means the need for a single device that can cope with the multiplicity of standards available. Also to be considered is where there are increasing traffic rates, but decreasing amounts of spectrum. These require ever more sophisticated signal processing algorithms.
Digital signal processing (DSP) technology, which can be tailored to specific processing requirements, in many ways embodies an ideal technology layer for communication applications, as it enables acceleration. For example, a decoder can be built within the chip itself, and even the instruction set for it.
This leads to what is believed to be the biggest problem - chip implementation. The problems lie with the compromise between power consumption and flexibility.
Any SDR requires a lot of processing power, resulting in increased power consumption. This leads to a short battery life in the typical handset, to leave the challenge of making the chips smaller and more power efficient.
Finding the right platform
However, power consumption is only one aspect. At the present time, the application interface which will set the parameters of the different radio frequencies have not been standardised. Corba and Java have been suggested, but no standards bodies have agreed on either.
The complexity of communication protocols is now so high that no single company can hope to provide a solution for all of them. There is no commercial system currently in the market that enables multiple vendors' products to be integrated.
A somewhat neglected protocol, in addition to the others, is digital radio. A user with a laptop or other receiving device could pick up data over digital radio airwaves that the digital radio licence holders are planning to send out.
Only recently, NTL invested in RadioScape, a company involved in developing SDR technologies, to roll out the entertainment data services it plans to deliver as part of various digital licence alliances.
And these digital licence holders could be the key to ensuring that 3G high-speed data services can be rolled-out in the next couple of years.
Billions of pounds have been shelled out for 3G licences, but digital radio licensees only paid around £10,000 each, which puts them in a better position to establish data services based on SDR.
While this technology may seem to be the Holy Grail of network integration (more bandwidth and better functionality), further investments will be needed to get SDR from prototype to mass market and only then it will do so in piecemeal fashion.
Who controls SDR?
The SDR Forum is an organisation that aims to set the standards for SDR itself. Its membership numbers up to 100, including companies such as Lucent, Nortel, Nokia and NTT DoCoMo as well as Orange and RadioScape in this country.
It has been working with global standards bodies and other industry groups to develop SDR standards and make it commercially viable.
The forum expects the widespread adoption of this technology to take place in the next two to three years as the 3G networks themselves start to roll-out.
See also:
All Network Infrastructure
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