Proposal of design method for fixed wireless telecommunication in 400-MHz band and measurements of propagation inside office buildings

Abstract

There is no clear design guide for fixed wireless links for instrumentation in office buildings. In fact, there are no quantitative data for the propagation and fading characteristics to be utilized in link design. This article intends to provide a design guide for intermittent communication links for instrumentation in office buildings. The approach is as follows. The case where only instantaneous variation with time exists is considered. The receiver power level required to satisfy the specified transmission quality is determined. The variation of the central value depending on the site is represented as a function of the distance between the transmitter and the receiver. By superposing the variation of the central value of the site on the specified distance and variation of the instantaneous value, the zone periphery outage probability is derived, based on the case where the required transmission quality is not maintained. Then, a design guide based on the communication distance is proposed so that the outage probability is kept below the specified value. The communication completion rate is measured quantitatively by a long-term check of communication incompletion cases. The propagation characteristics of electromagnetic waves are measured for the 400-MHz band in an actual office environment. It is shown by experiments that the variation of the received power level follows the Rayleigh distribution and the distance attenuation follows an exponential function, as in a waveguide. Design of a link is attempted for an air-conditioner wireless telecontrol system, using the proposed communication distance estimation based on coefficients determined by experiment. The communicable distance is estimated as 21 m on the same floor with a seven-fold code redundant selective SD antenna. It is estimated that the required transmission quality cannot be realized in communication to adjacent floors. The communicable distance is estimated as up to 14 on in the same floor by the selective SD antenna, when the seven-fold extended code is not used. © 2000 Scripta Technica, Electron Comm Jpn Pt 1, 83(8): 42–52, 2000