rray (Courtesy of European Antennas Ltd.) from an economic standpoint to providing the same increment in gain at many more subscriber locations. Base Station Antenna Location Having mapped out the intended area for the MAN, the local terrain characteristics and availability of suitable antenna locations would have been assessed as part of the physical site survey. The results of this survey will be analysed to define the minimum number and optimal location of base stations required to serve the target area. There are two basic options to consider in deciding how to achieve coverage of the target area - coverage from the periphery (Figure 13-5) or from the centre as shown in Table 13-1. If IEEE 802.16 is the MAN technology being deployed, an individual base station range of 3-10 kilometres should be considered when mapping Implementing Wireless MANs Table 13-1: MAN Target Area Coverage Options Option Considerations Coverage from the A number of locations are identified to provide coverage periphery of the target from the periphery of the target area. This option may be advantageous where local terrain, such as nearby hills, can provide line-of-sight coverage of a wide area. This may also allow subscribers to select the best base station from several different directions. Coverage from the In this option one or more base stations are placed on centre of the target area tall structures located within, and preferably close to the centre of, the target area. out coverage. Depending on the size and shape of the target area, a combination of peripheral and central coverage may be required (Figure 13-6). Either of these options can be supplemented by the use of additional bridge linked base stations that can be positioned to fill in parts of the target area that may be shielded by high buildings, local terrain or other obstacles. Having established the general layout of base stations required to cover the target area, Table 13-2 summarises issues that need to be considered in determining specific locations for BS antenna