OVERVIEW

ITU has called the future cellular networks 3G networks or IMT-2000; the previous term was Future Public Land Mobile Telephone System (FPLMTS). The performance for IMT-2000 air interference can be summarized as: ^{[1] [2] [3]}

• Wideband CDMA systems

• Spectrum bandwidth 5 MHz

• Full coverage and mobility for a data rate of 144 kbps to 384 kbps

• Limited coverage and mobility or no mobility for 2 Mbps

• High spectrum efficiency compared to 2G system

• High flexibility to introduce new and multimedia services

The 3G features:

• Provision of multirate services

• Packet data

• A user-dedicated pilot for a coherent uplink

• An additional DL pilot channel for beam forming

• Intercarrier handover

• Fast power control

• Multiuser detection

IMT-2000 has published a minimum performance requirement of a 3G wireless system, which is for both circuit-switched (CS) and packet-switched (PS) data:

• Data rate of 144 kbps in the vehicular environment

• Data rate of 384 kbps in the pedestrian environment

• Data rate of 2 Mbps in the fixed indoor and pico cell environment

The 3G systems concentrating on the three ITU-adopted systems using CDMA technology are WCDMA-UTRA (Europe), WCDMA-ARIB (Japan), and cdma2000 (North America).

3G consists of the three systems shown in Fig. 6.1, also called three modes because in the future, the three systems can have the features of hooks and extension to make intersystem connections among them.

Figure 6.1: 3G's three standard systems