Indoor positioning with OFDM Visible Light Communications

Abstract

Visible Light Communication (VLC) technology using light emitting diodes (LEDs) has been gaining increasing attention in recent years as it is appealing for a wide range of applications such as indoor positioning. Orthogonal frequency division multiplexing (OFDM) has been applied to indoor wireless optical communications in order to mitigate the effect of multipath distortion of the optical channel as well as increasing data rate. In this paper, we investigate the indoor positioning accuracy of optical based OFDM techniques used in VLC systems. A positioning algorithm based on power attenuation is used to estimate the receiver coordinates. We further calculate the positioning errors in all the locations of a room and compare them with those using single carrier modulation scheme, i.e., on-off keying (OOK) modulation. We demonstrate that OFDM positioning system outperforms its conventional counterpart.

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.…”

“…[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] . In this Letter, a visible light positioning algorithm based on the RSS and artificial neural network training is proposed to achieve highly precise and efficient indoor visible light positioning in scenarios with a diffuse optical channel.…”

“…[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.…”

A State-of-the-Art Survey of Indoor Positioning and Navigation Systems and Technologies

“…For example, H. S. Kim et al (2013) developed an LED positioning system based on Carrier Allocation VLC (CA-VLC) to alleviate inter-cell interferences, using trilateration technique. Likewise, the studies by L. Li, Hu, Peng, Shen, and Zhao (2014), Yin et al (2015), Aminikashani et al (2016), Han, Cheng, and Liu (2016) and Q.-L. Li, Wang, Huang, and Wang (2016) all used the trilateration technique while W. Zhang et al (2014) used the triangulation technique. On the other hand, the study by Aminikashani et al (2016) used multi carrier Orthogonal Frequency Division Multiplexing (OFDM), positing that this technique is more efficient than the single carrier OOK modulation scheme because the DC gain of the optical channel can be better estimated.…”

“…It is generally based on the intensity modulation and direct detection (IM/DD) modulation scheme (Yin, Wu, & Haas, 2015;Aminikashani, Gu, & Kavehrad, 2016). VL positioning system consists of a light source or base station (transmitter), a mobile terminal or image sensor (receiver) and a LOS communication channel (W. Zhang, Chowdhury, & Kavehrad, 2014).…”