Boundaries between radio cells-influence of buildings and vegetation

In mobile radio services, an efficient utilisation of the frequency spectrum can be achieved by the small-cell concept. However, small cells lead to high hand-over rates of the radio link between the mobile and the different base stations in the vicinity of the cell boundary. The absolute field-strength levels and the differnces between them when received from various base stations are regarded as 'hand-over criteria'. In the UHF range, however, the field-strength level is subject to large variations, even in flat terrain, owing to varying land usage. The Deutsche Bundespost has performed mobile radio measurements at 450 MHz in an area situated to the south of Frankfurt, about half-way between two base stations. The land usage in this area situated to towns, forests and open fields are mixed. The field-strength levels were recorded along all main roads in this region, having a total length of about 100 km. The measurements and statistical evaluation of more than 10 million samples are described in detail. The influence of the mixed land usage and the hand-over criteria is discussed with the aid of a 3 km drive.