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The subTHz kiosk aims at downloading huge data rates; thus, we consider here the kiosk antenna as the “transmitter” and the user equipements as the “receivers”. The simulated scenario is composed of a fixed kiosk transmitter located in a wide indoor avenue in a shopping mall. More precisely, the kiosk transmitter is in the middle of a large patio, facing an intersection between two avenues; the transmitter vicinity may be considered as “open”, as shown in Fig. 17. The simulated receivers are distributed over the surface of half a disk in front of the kiosk transmitter with radius 10 m. Fig. 18 (right) illustrates the various receiver positions that have been predicted, with a specific antenna orientation at each position i.e. towards the kiosk. All receiver positions are in line-of-sight (LoS).
The transmitter and receivers have each an antenna array of rectangular shape, composed of dual-polar antenna elements (either V/H or +/-45° linear polarizations at the transmitter, and V/H polarizations at the receiver). The size of the transmit antenna array is (16 x 8) x 2 polarizations. The size of the receive antenna array is (8 x 8) x 2 polarizations.
The channel properties are simulated for a central frequency of 150 GHz, and a channel bandwidth of 2 GHz divided into 20 sub-carriers.
The channel H matrix between the transmitter and all receivers is saved into a Matlab file. For each receiver, the H matrix is formed of 128 x 64 x 20 = 163 840 complex coefficients. One coefficient corresponds to the propagation channel gain between one transmit antenna element and one receive antenna element for a specific sub-carrier.
Note that if someone wants to get the H matrix for smaller antenna array, e.g. for a 8 x 8 MIMO system, and for a single frequency, then a relevant sub-matrix can easily be extracted from the full predicted matrix.
Fig. 1: Kiosk environment.
Fig. 2: Side view – three different considered transmitter heights and orientations (left); Top view – position and orientation of the receiver antennas (right).
Table 1 gives some additional details on the transmitter properties. Actually, we simulated twelve different transmitter situations, with an omni-directional or directional radiation pattern (at the antenna element), three different heights (see Fig. 3), and two polarization states (V/H or +/-45°).
The receiver detailed properties are given in Table 2.
The predicted ray-paths in Fig. 3 show that the LoS direct-path is dominant. However, there are some significant reflections on the ground, ceiling, pilar and surrounding walls that contribute to the channel diversity, thus leads to fading variations along the H matrix in both spatial and frequency dimensions. As expected, those variations reduce when changing the transmit omni-directional antenna for a directional pattern.
Figure 3 : Examples of prediction ray-paths.
Finally, Table 3 gives the list of Matlab MIMO channel sample files that are available on the open repository. “BS” stands for “base station”, which is equivalent to the “transmitter” in this scenario.