To describe the process of this design method clearly, we set up a coordinate system in Fig. 1, defining the floor as the
X-
Y plane, the height direction as the
Z-axis, and point
O is the coordinate origin. Figure 1 shows the optical MIMO system in a configuration used in the literatures [
1,
13]. We adopt LUXEON K2 LED [
22] for lighting system and optical MIMO communication system. The room size is 5.0 m × 5.0 m × 3.0 m, and the distance between the ceiling and the receivers’ plane is 2.15 m. The LEDs fixed on the ceiling of the room are arranged in the square arrays, which are like that of the literatures [
23,
24]. Furthermore the, LED’s luminous intensity is isotropic, and consequently the LED-to-LED of the lamp has the same spacing. In the configuration of the square LED array, the LED-to-LED have same separation,
. Generally, the luminance of lights is standardized by International Organization for Standardization (ISO). According to the ISO standard, the luminance of 300-1500 lx is required for a work office, but the typical luminous power of LUXEON K2 LED is only 130 lm from the datasheet, therefore, 64 LEDs can provide sufficient illuminance in this system. Each LED lamp has 4 × 4 LEDs. The center positions of lamps are A: (1.575, 1.575, 3.0), B: (3.525, 1.575, 3.0), C: (3.525, 3.525, 3.0) and D: (1.575, 3.525, 3.0). It is assumed that all LED lamps are driven by different modulation circuits to achieve high speed transmission. The ceiling, the wall and the floor respectively have reflective index values of 0.8, 0.5, 0.2. Four receivers are set on the desk, each of them contains an optical concentrator, followed by a photo detector and preamplifier, and the center position of the receivers (Rs) is R
1: (2.5, 2.5, 0.8), R
2: (1.5, 1.5, 0.8), R
3: (0.5, 0.5, 0.8) and R
4: (2.5, 0.5, 0.8).