Channel Modelling for Multiprobe Over-the-Air MIMO Testing

Abstract

This paper discusses over-the-air (OTA) test setup for multiple-input-multiple-output (MIMO) capable terminals with emphasis on channel modelling. The setup is composed of a fading emulator, an anechoic chamber, and multiple probes. Creation of a propagation environment inside an anechoic chamber requires unconventional radio channel modelling, namely, a specific mapping of the original models onto the probe antennas. We introduce two novel methods to generate fading emulator channel coefficients; the prefaded signals synthesis and the plane wave synthesis. To verify both methods we present a set of simulation results. We also show that the geometric description is a prerequisite for the original channel model.

Experimental Evaluation of MIMO Terminals With User Influence in OTA Setups

“…Recently, the multi-probe anechoic chamber (MPAC) method has been selected in CTIA and 3GPP standardization [7]. With this method, realistic propagation environments in which the performance of the device is evaluated can be physically emulated in a controllable and repeatable manner [8]. Research work in MPAC setups has been limited to free space conditions.…”

“…The free space mode represents the case where no user phantom is present. This mode is generally assumed in the literature for MIMO OTA testing [7], [8]. As for the user influence mode, only talk mode where the user holds the DUT in the right hand, with the DUT pointing to the right ear was investigated [2], as shown in Figure 3.…”

Wideband MIMO Channel Capacity Analysis in Multiprobe Anechoic Chamber Setups

“…The test area size depends directly on the number of probes used for synthesizing the radio channel [3], [4]. Many measurements have been performed to verify how well the emulated channel models follow the target models in terms of channel parameters such as power delay profile, power Doppler spectrum, cross polarization ratio (XPR) and spatial correlation at the Rx side, see e.g., [5], [6].…”

“…Many measurements have been performed to verify how well the emulated channel models follow the target models in terms of channel parameters such as power delay profile, power Doppler spectrum, cross polarization ratio (XPR) and spatial correlation at the Rx side, see e.g., [5], [6]. In the literature, to appropriately assess how accurately the simulated power angle spectrum (PAS) approximates the target PAS, the difference between the simulated spatial correlation and the target spatial correlation |ρ −ρ| is chosen and used as a measure to determine the test zone size [3], [4], [7]. However, there is a concern whether |ρ −ρ| is the optimal figure of merit (FoM) to determine the test area size, as the ultimate goal is to investigate whether performance of MIMO capable terminals, e.g.…”

Evaluation of reflections in a MIMO OTA test setup

“…Channel emulation is discussed in [2,3,4]. Realizing defined channel conditions has been investigated with different setups.…”