Measurements and modelling for D2D indoor wideband MIMO radio channels at 5 GHz

Based on the indoor wideband multiple-input multiple-output (MIMO) device-to-device (D2D) measurements at 5 GHz with 100 MHz bandwidth carried out in University of Oulu, Finland, this study investigates the characteristics of indoor D2D radio channels with the same antenna height when both of the transceivers are moving or one end is fixed. The received power for the D2D channel is investigated by using double- and multiple-Rayleigh distributions. It turned out that the received powers follow joint Rayleigh and double-Rayleigh distribution as well as approximately Rayleigh distribution in non-line-of-sight and line-of-sight scenarios, respectively. The angular distributions and their correlation of the angle-of-arrival and angle-of-departure in the azimuth and elevation planes are investigated in order to build three-dimension model of Doppler power spectra and compare with the measurements. The channel parameters are derived from the measurements and compared with WINNER A1 scenario to find the differences between the D2D and conventional fixed-to-mobile (CF2M) channels. From the results, one can find the differences between the D2D and CF2M radio channels and better understand the physics for the D2D channel. Meanwhile, the channel parameters derived herein are important in the link and system level simulations for indoor D2D radio systems.