Title :
Channel sounder for 5.5 GHz wireless channels
Author :
Charles, S.A. ; Ball, E.A. ; Whittaker, T.H. ; Pollard, J.K.
Author_Institution :
Dept. of Electron. Eng., Univ. Coll. London, UK
Abstract :
A channel sounder based on correlation of a maximum-length sequence is described. The sounder is designed for the evaluation of the absolute path loss and multipath delay spread of a fixed wireless local loop channel at 5.5 GHz. The sounder achieves good performance with relatively simple hardware. There are two key issues which must be addressed: compensation for drift and offset between the local oscillators and compensation for the distortion caused by the non-ideal nature of the measurement chain. Two-stage down-conversion is used with the second stage and subsequent processing being performed in software. A novel method of allowing for local oscillator drift without the use of a hardware carrier tracking mechanism is presented. The intermediate frequency is estimated by software before second-stage demodulation. Distortion due to the measurement chain is compensated by means of a matched filter. Measurement of absolute path loss and time variance of the channel are also considered. Example results are presented.
Keywords :
correlation methods; delays; frequency estimation; loss measurement; m-sequences; matched filters; microwave propagation; multipath channels; radio access networks; 5.5 GHz; SHF; absolute path loss measurement; channel sounder; demodulation; distortion compensation; drift compensation; fixed wireless local loop channel; intermediate frequency estimation; local oscillator drift; matched filter; maximum-length binary sequence; maximum-length sequence correlation; measurement chain; multipath delay spread; offset compensation; performance; software; two-stage down-conversion; wireless channels;
Journal_Title :
Communications, IEE Proceedings-
DOI :
10.1049/ip-com:20030356