On Polarization and Frequency Dependence of Diffuse Indoor Propagation

Abstract

Abstract-The room electromagnetics (RE) theory describes the radio propagation in a single room assuming diffuse scattering. A main characteristic is the exponential power-delay profile (PDP) decaying with the so-called reverberation time (RT) parameter, depending only on the wall area, the volume of the room and an absorption coefficient. The PDP is independent on the location in the room, except for the arrival time. Based on measurements in a room with a spherical array of 16 dualpolarized wideband horn antennas, the current work studies how the RE parameters depend on the receiver (Rx) antenna polarization and orientation. Also the frequency dependence is investigated, with measurements done at both 2.3 GHz and 5.8 GHz center frequencies. The RE theory was found to fit well to the measurements with a RT in the range 22-25 ns. Only small differences were found due to the polarization and the channel gain was depending approximately as expected with frequency.

Reverberation Time and Power Model in Indoor Wireless Scenarios

“…A number of experimental analysis using room electromagnetics can be found in existing studies. Here, studies with sufficient data for reverberation time values, propagation geometry and materials in open literature are re-investigated as supplementary [7], [20][21][22]. These data are processed using the following functions:…”

“…Over the last decade, studies based on room electromagnetics manage to provide more insightful physical understanding for indoor wireless channels [1][2][3][4][5][6][7]. The room electromagnetics theory [1] points out that the electromagnetic waves in indoor wireless scenarios and the acoustic waves in room acoustics share similar behaviors in various aspects.…”

“…The index describes the decaying of primary component in reverberation models, and it can get closer to 2 than in traditional models [4]. Reverberation time is a key parameter in reverberation models [5][6][7], [9], [10]. It originates from room acoustics, where it is defined as the time in which the total energy falls to one millionth of its initial value [11][12][13].…”

“…Hence, the modeling of reverberation time is of great importance, as it is a basis of reverberation models. Most reported electromagnetic reverberation time models are based on either Sabine's or Eyring's equation [1], [4][5][6][7], [11], [12]. In analogy with acoustics, it is proposed in the two equations that electromagnetic reverberation time in an indoor wireless scenario is solely dependent on three parameters that are fixed by propagation geometry and materials: volume, surface and average absorption coefficient of the environment [11][12][13][14].…”

“…Also, the small scale fading characteristics including the modeling of PDP are rarely investigated. Meanwhile, most of these studies are limited in enclosed environments like conference rooms and classrooms [1][2][3][4][5][6][7], but semi-enclosed scenarios are rarely studied. Therefore, it is highly desired to develop a novel, accurate and more general reverberation model for indoor wireless scenarios.…”