Spherical Outdoor to Indoor Power Spectrum Model at the Mobile Terminal

The power received by a mobile handset depends on both the radiation pattern of the handset as well as the signal distribution in the environment. The handset radiation pattern is to some extend directive and therefore the directions from which the signals are received are important. In indoor environments the signals often penetrate buildings mainly through windows and doors and therefore the signals arrive at mobile handsets from specific directions. The mean effective gain (MEG) is a measure of the power received by an antenna in a certain environment, and is a useful measure of the performance of an antenna in the mobile channel. The MEG may be measured directly with the antenna in question by computing an average of the received power in a given environment. Another method is to compute the MEG using the spherical radiation pattern of the antenna and the spherical distribution of incoming power, both measured including polarization properties. Although this method is more demanding from a measurement point of view, it is attractive because the measurement of the antenna is separated from measurement in the mobile channel, which gives some more flexibility in testing and designing antennas. In order to facilitate handset performance evaluation, models of the power distribution are needed, and these models should be based on measurements. The work in [Knudsen, Pedersen, 2002] reports on a large measurement campaign where spherical channel impulse responses are measured using a horn antenna mounted on a pedestal with two axes. The campaign is described in CPK Annual Report 2001. (Mikael B. Knudsen, Gert F. Pedersen)