Measurement and modelling of a radio channel for wireless local loop applications

Fixed radio communication systems seem to be a promising alternative solution for a lot of applications which require more and more bandwidth. Advanced equipment uses some knowledge of the radio channel impulse response to enhance the quality of the communication link. In this paper, a measurement tool for determining the impulse response of a radio channel is described. This tool is part of a WLL system using CDMA technology at a chip rate of 3.84 Mchips/s and an RF bandwidth of 5 MHz. Furthermore, some results of a measuring campaign are presented. The measurements were performed in a suburban environment in Berlin at 1.95 GHz. In many cases these results are in good agreement with the proposed models recently published by the IEEE 802.16 broadband wireless access working group. However, some other results indicate that an extension would be necessary to describe the statistics of the echoes more correctly.