INTRODUCTION TO ALL RELEVANT WIRELESS TECHNOLOGIES
Note: The below text is part of a paper, to be presented by Klaas van Gend at the NLUUG autumn conference 2006. This page has a slight bias towards The Netherlands.
Wireless mobile communication already exists for quite a while. Two famous "zero" generation devices are the 'Walky Talkies' and the "Bakkies". All devices share the same radio frequency. If one wants to talk, he pushes the send button and all others have to listen. It's very easy to eavesdrop - just listen to the right frequency.
During the 80s, Dutch national telecom operator PTT installed the first analog cellular networks for mobile communication. Throughout the Netherlands, antennas were erected and "carryable" phones (approx 5 kg!) could call into these networks. The first generation (1G) networks weren't a real success due to very heavy batteries and high costs for the end users.
In 1982, a French organisation called "Groupe Spécial Mobile" had started investigations into a digital wireless communication network. The biggest advantages were the reduction of interference and distortion in the audio and to increase security. At the end of the eighties, the EU agreed to use this new system and standards body ETSI took over maintainer ship. By the end of 1991 the first GSM network was aired in Finland, with the other countries quick to follow. GSM is called a 2G network, and one important aspect is that during a call, the phone has a fixed-bandwidth communication channel to the antenna.
With the rise of mobile computing, this fixed bandwidth imposed a problem for utilising this network for data exchange. There is no need for a full communication channel as users aren't in a constant need for data. A packet switched network like the regular IP protocol would be ideal - where several users together can use the bandwidth. This became the 2.5G network GPRS "General Packet Radio Switch". Due to the packet switching, traffic is no longer taxed per time unit but per megabyte.
Dutch operator Telfort carries another extension to GPRS, called EDGE or "Enhanced Data Rates for GSM Evolution". This 2.75G network changes the way the radio signal is used, thereby tripling the throughput. This impacts both the cell phones and the equipment used by operators. This is why most operators refuse to switch to EDGE and jump to UMTS directly.
A breakthrough in radio technology allowed for a new coding of radio signals. This was called W-CDMA and is essentially different from the TDMA coding of the GSM network. Together with new frequencies that allow higher bandwidths, these 3G networks are called UMTS or "Universal Mobile Telecommunication Systems". As explained in the beginning of this paper, the UMTS network requires all-new equipment.
Another extension to the radio technology of UMTS is called HSDPA or "High Speed Downlink Packet Access". This 3.5G network protocol creates the notion of a dedicated downlink channel. Other improvements are in the area of retransmits and error correction. As well as improved data rates that are associated with HSDPA one of the key benefits that are seen is the reduction on latency, improving the round trip time for applications.
This is not the end of development, the 3.75G technology HSUPA is ready for deployment and 4G networks are being designed right now. And still, the public is afraid of more antennas and the damage of radiation to the human physiology. There is a technology push, but the question remains if the public is interested in those improvements or whether it is "good enough".
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