Impact of Multipath Reflections on the Performance of Indoor Visible Light Positioning Systems

Abstract

Visible light communication (VLC) using lightemitting-diodes (LEDs) has been a popular research area recently. VLC can provide a practical solution for indoor positioning. In this paper, the impact of multipath reflections on indoor VLC positioning is investigated, considering a complex indoor environment with walls, floor and ceiling. For the proposed positioning system, an LED bulb is the transmitter and a photodiode (PD) is the receiver to detect received signal strength (RSS) information. Combined deterministic and modified Monte Carlo (CDMMC) method is applied to compute the impulse response of the optical channel. Since power attenuation is applied to calculate the distance between the transmitter and receiver, the received power from each reflection order is analyzed. Finally, the positioning errors are estimated for all the locations over the room and compared with the previous works where no reflections considered. Three calibration approaches are proposed to decrease the effect of multipath reflections. Index Terms-Indoor positioning, visible light communication, multipath reflections, impulse response, received signal strength.

Real‐Time Software‐Defined Adaptive MIMO Visible Light Communications

“…In fact, complex channel conditions are expected to be changed dramatically, and spectral efficiency must be optimized adaptively in practical indoor wireless mobile communications [14,15]. For example, the MIMO VLC system using fixed spatial multiplexing will suffer link interruption, once any sub-channel condition becomes degraded [16,17].…”

Artificial neural-network-based visible light positioning algorithm with a diffuse optical channel

“…The results show that in a typical scenario with a diffuse optical channel, the average positioning error of the proposed positioning algorithm is about 13 times less than the typical RSS-based positioning algorithm, and the trained artificial neural network is effective to all the points on the receiver plane, which outperforms other relevant methods (in Refs. [12,13], the corresponding improvements are about 1.2 times and 3.9 times, respectively). The positioning time of the proposed algorithm is less than the typical RSS-based positioning algorithm by about two magnitudes, which means it is more time-efficient and suitable for the positioning of moving objects.…”

“…The impact of a diffuse optical channel on a visible light positioning system is investigated in Ref. [12], and the calibration approaches, such as select stronger LED signals and shortening the distances between LEDs, have been proposed to decrease the performance degradation. In other research, the orthogonal frequency division multiplexing (OFDM) technique has been applied to mitigate the distortion of the diffuse optical channel, and the root mean square (RMS) error of the whole positioning scenario can be reduced about four times [13] .…”

“…[10][11][12][13]. In the simulation, a typical indoor scenario, i.e., a four wall 5 m × 5 m × 3 m empty room, is investigated.…”

Iterative positioning algorithm to reduce the impact of diffuse reflection on an indoor visible light positioning system

“…3, and the average positioning error of 2.4 cm is achieved in experiments. [10][11][12][13] Calibration approaches that select stronger light-emitting diodes (LED) signals and shorten the distances between LEDs have been proposed to amend the negative effect of diffuse reflections in Ref. 4, the RSSbased positioning algorithm combined with a maximum likelihood estimator has been proposed to improve the performance of a positioning system.…”