3G NETWORK
Today''s mobile networks were originally optimized for voice traffic. To carry large amounts of data traffic quickly and cost-effectively improved radio interfaces will be needed, capable of providing higher-bandwidth connections to more users simultaneously
Wideband radio technology has been optimized for multimedia
services and high-speed Internet access. It will also be very spectrum-efficient, helping make the most of available spectrum. Radio access for 3G will be provided in two ways: the addition of new wideband radio technology to make use of newly available radio spectrum; and the evolution of current radio technology to provide higher-speed capabilities. The International Telecommunications Union (ITU) recommendations for the IMT2000 standard for next-generation services, a data rate of 2Mbit/s indoors are envisaged. In the wide-area environment - on suburban streets, on the train or in the car, for example - IMT-2000 envisages a data rate of up to 384kbit/s.
Multi-band, multi-mode phones have already shown how innovative terminal design can make the frequency of the radio access an irrelevance for users of mobile services. In the same way, "2G13G-capable" dual-mode phones will provide transparent access to services delivered over different radio networks. 3G coverage can be built out in line with market demand - as an overlay network, for example.
What is the effect of 3G? Implementing 3G does not just mean standardizing a new radio interface. New techniques and evolution strategies for delivering 3G are needed for all levels of the network.
When the current mobile standards were developed, they were generally applied right across the network. A GSM network is GSM at the handset, radio communications and core network levels. Much the same goes for TDMA (ANSI-136 digital mobile standard) and cdmaOne (ANSI-95, a CDMA-based digital mobile standard). In the case of 3G, a different approach is being taken. There is one standardization process for the radio network and another for the core network. That is why, when the industry talks about 3G wideband Radio Transmission Technologies (RTTs), it is only the radio communications part of the network that is being discussed. The core network is being developed and standardized in parallel, and in many cases will be an evolution of today''s core networks. The diagram on page 21 shows how a 3G network will look. There will be a core network that has transport "pipes" for information flow, nodes that route the traffic, and nodes where the services are located. The core network will also have connections to other wired and mobile networks, to provide interconnectivity with the global telecoms networks. Connected to this core network will be the mobile radio network, providing the wideband interface for users.