Mobility is an important requirement of future personal telecommunication systems. The performance of mobile radio systems is strongly affected by the characteristics of the mobile radio channel. Wideband channel sounding techniques and the results of various measurement campaigns in different environments are presented. The relationships between the system performance and channel parameters were evaluated by means of computer simulations. Results are presented for the GSM system and the DECT system using measured channel data. The application of diversity and equalisation as countermeasures against performance degradations caused by the mobile radio channel are discussed.

The efficiency of frequency utilization in mobile radio strongly depends on the performance of handoffs. Criteria for handoffs are usually derived from measured carrier-to-interference ratios (C/I). However, in mobile radio signal levels vary so rapidly that channel allocation cannot be performed in real time for optimum C/I. On the other hand, too many handoffs reduce frequency efficiency. The determination of cell boundaries, which are not only governed by C/I, but allocated to geographical lines in the terrain avoid unnecessary handoffs. In addition to C/I auxilary data are measured in the German system C and processed to detect the cell boundaries. The improvements gained from this procedure are demonstrated by measured results.