sector22. Hence, to prevent the usage of four feeder cables, e.g. we can apply feeder 20 This combination gets doubled for the second antenna branch. 21 As in the wide antenna, this combination has to be doubled for the second antenna branch. This does not apply to the solution with broadband antennas for GSM 1800 and UMTS. The UMTS Network and Radio Access Technology sharing with additional diplexers and use two feeder only. Figure 7.20 [7] illustrates this logic with a cross-polarized dual band antenna. Dual-band Dual-band antenna antenna +4 5° Without diplexer Diplexer Diplexer With integrated Feeder diplexer in the Feeder BTS side Diplexer Diplexer Dual-band Dual-band Figure 7.20 Dual band antenna with and without diplexer. Dual band antennas are characterized by being suitable for both frequency ranges with separate input connectors. Although dual band antennas suit ideally both GSM 1800 and UMTS frequency ranges, they lead to a double number of antenna connectors when compared to corresponding single band antennas if sufficient diplexers are not used. Thus, it seems more efficient to upgrade dual band antennas with additional diplexers in order to decrease the number of antenna connectors by a factor of two. In this case the required feeder system will remain the same as for a single band antenna system. The trade-off of extra investment for additional diplexers and expense on the feeder system will depend in the end on the losses due to feeder attenuation. In any case, when doing a transition from single band to a dual band system, the existing feeder system can be used, ensuring a fast installation during retrofit if the necessary diplexers are in place [7]. 7.13 CONCLUSIONS In this chapter we have covered essential aspects for 3G network deployment. We have brought together the main issues of network dimensioning on the radio, core network, as well as transmission. We have used a field study to illustrate key parameters and in- troduce some relevant assumptions when trying to size a network for a given p