rol node, known as the Radio Network Controller (RNC) in 3G standards. An RNC is served by several databases such as a Home Location Register (HLR) which checks if a mobile device is a valid subscriber. Several gateways connect voice and data traffic to the fixed network. Broadband Telecommunications Technologies and Management Fixed Location network Register (HLR) Serving Support (SGSN) Radio Network Controller Stations (RNC) network Mobile Station (MS) Figure 13.3 Wireless node connection to a core network This chapter lists and discusses possible networking topologies for wireless broadband tele- communications systems. We discuss the characteristics of these topologies and how they perform considering the specific challenges of broadband telecommunications systems. We also discuss the convergence of wireless and fixed networking technologies and how network coverage may be automatically optimised as the number of base stations and traffic levels change in different geographical areas. Cell Structure The classic wireless network design is based on a star topology, where a central base station serves mobiles in a circular area with the base station at its centre. As shown in Figure 13.2 several cell structures can be defined based on the capacity of the base station and the size of the coverage area. Different cell size configurations are further described below. Macrocell A macrocell is generally a wireless network area with a radius of several hundred metres to tens of kilometres served by a single base station. The macrocell base station utilises powerful antennas installed atop a tower or a tall building at a height of 30 m or more. Transmission power from the antenna can be up to tens of watts, although it typically is between 5 W and 10 W (37-40 dBm). The base station transceiver equipment is generally housed in a room inside the building or within a box at the base of the tower where an appropriate temperature may be maintained. With recent reductions in base station equipment size, they are at times pla