BILATERAL AVERAGING OVER RECEIVING AND TRANSMITTING AREAS FOR ACCURATE MEASUREMENTS OF SECTOR AVERAGE SIGNAL STRENGTH INSIDE BUILDINGS

In defining path loss for narrowband systems, it is common to introduc e the concept of the sector or local average in order to remove the ra pid (Rayleigh or Rician) fading. As originally developed for cellular mobile radio (CMR) systems, the sector average is obtained from the sp atial average of the received signal as the mobile traverses a path of 20 or so wavelengths. This approach has also been applied indoors wit h the assumption that a unique average could be obtained by moving eit her end of the radio link. Unlike the CMR path for indoor propagation, however, both ends of the radio link are in a rich multipath environm ent. It is shown both theoretically and experimentally that moving bot h ends of the link is required to achieve a unique average. When avera ging is accomplished by moving only one end, the result can experience variations of as much as +/-2 dB when the other end is moved by a fra ction of a wavelength.