63G Transmission Network Planning and Optimisation
6.1 Basics of 3G (WCDMA) Transmission Network Planning
6.1.1 Scope of Transmission Network Planning
The scope of transmission network planning includes the region constituting the interfaces between the BS and RNC, between the RNC and CN, and between RNC and RNC, i.e. Iub, Iu (CS and PS) and Iur, respectively (Figure 6.1).
Figure 6.1 Scope of transmission network planning in 3G (WCDMA).
6.1.2 Elements in 3G Transmission Networks
6.1.2.1 Base Station (Node B)
Base stations play an important role in 3G transmission networks. Their role changes significantly in 3G as compared with GSM transmission networks. In GSM transmission networks, if the number of transceivers or TRXs was knows, the Abis capacity calculation could be done. However, with data coming to play an important role, the components of the base station also change, thereby changing the dimensioning and functioning of the network. A simplified block diagram is shown in Figure 6.2. A brief overview of the functions of these blocks is given below.
Figure 6.2 Block diagram of 3G base station.
6.1.2.1.1 Antenna Filter and Power Amplifier (AF and PA)
The filter isolates the transmitted and received signals. The amplifier amplifies the received signals.