imensioning parameters play a very important part in the whole process. The network is initially dimensioned based on factors such as existing knowledge and equip- ment limitations at the time when the actual network is launched. Then lots of factors and parameters change, SO it becomes necessary to make a reassessment of the dimensioning. The general data consist of the actual implemented and commissioned data, such as topology, link budget calculations, interference analysis, capacities of the links, etc., along with the actual received power, system curves and recoded fade margins. Also, for long hops, fade margins can be recorded over a certain period. Availability performance data can also be recorded for a longer period. The radio network parameters are again subdivided into dimensioned and optimised parameters. Any effects of the optimised radio parameters can be seen on the transmission TRANSMISSION NETWORK OPTIMISATION network parameters. In this way, later on down the process, the relationship between certain radio parameters and the transmission network performance can be examined, allowing the setting of these parameters such that the performances of both the radio and transmission networks are optimal for best E2E (end-to-end) QoS for the network. Once this has been done, the optimised parameters are looped back again to the network analysis SO as to cross-check whether they are giving the desired network performance. 3G Core Network Planning and Optimisation 9.1 BASICS OF CORE NETWORK PLANNING Core network planning of a third-generation (WCDMA) system consists of both circuit core and packet core planning. 9.1.1 The Scope of Core Network Planning The scope of core network planning includes dimensioning of network elements such as MGW, MSC (and VLR) and HLR (and AC/EIR) from the CS side, while the PS core will include SGSN, GGSN along with interfaces. 9.1.2 Elements in the Core Network Network elements in the 3G core network remain almost the same as seen in earlier chapters on core networks, except 