Error compensation in indoor positioning systems based on software defined visible light communication

Abstract

Visible Light Communication (VLC) paradigm allows the reusing of existing illuminating infrastructures in order to provide data communication. VLC can be considered a promising technology also for positioning in indoor environments, due to its potentially high accuracy and low costs. However, the main obstacle to the use of VLC for localization purposes is the high level of environmental noises, mainly due to sunlight. A novel approach, for easily measuring environmental noises and compensating their effects on localization results performed by an Indoor Positioning System (IPS) based on VLC, is proposed in this work. Frequency Division Multiplexing (FDM) is adopted to divide the total bandwidth into a series of non-overlapping frequency sub-bands corresponding to each signal, while an estimation of Signal to Noise Ratio (SNR), obtained through real time Power Spectral Density measurements in the proper frequency ranges, is exploited to compensate the error in positioning due to sunlight and other wideband external optical disturbing signals. The proposed approach has been validated through experimental tests, carried out using a simple deployment of low power lamps, low cost hardware and a software defined approach. In the region under test, receiver position has been experimentally detected with higher accuracy in comparison to classical FDM approach, confirming the correctness and effectiveness of our proposed technique. In order to further validate the proposed approach, an additive measurement campaign has been successfully carried out considering a scenario characterized by very low SNR levels.

An Indoor Visible Light Positioning System for Multi-Cell Networks

“…This section gives a brief overview of the operating principles of the existing VLP system models using WLEDs [14][15][16]. Although some research works in the literature consider multiple cells within the VLP architecture [14][15][16]20], they confine the simulation or experimental evaluations to the single-cell scenario. Therefore, let us first review the basic VLP model using WLEDs.…”

“…Therefore, let us first review the basic VLP model using WLEDs. Figure 1 presents a conventional single-cell architecture of the VLP system based on WLEDs for a two-dimensional (2D) location system [14,15,20]. In this architecture, three WLEDs placed on the ceiling in a triangular configuration provide coverage for the cell.…”

“…In [19], Huang et al employ received signal strength for a two-dimensional VLP system with a positioning accuracy of about 8 cm in a small 200 × 60 × 60 cm 3 space. On the other hand, there are only few research works that have proposed a VLP architecture for a multi-cell area based on white LEDs [14][15][16][20][21][22][23]. For example, in [24], Little et al proposed a multi-cell lighting testbed for a VLP system based on the RSS technique and radio frequency allocation.…”

Adaptive Modulation Control for Visible Light Communication Systems

“…VLC could be used for short distance underwater communication [2], [3], because the absorption coefficient of water at optical frequencies (especially in the blue range), is several times lower than the one shown at lower frequencies of the electromagnetic spectrum. VLC paradigm has also been considered to obtain affordable indoor positioning operations [4], [5], and portend future vehicle to vehicle communication [6]. Since frequency spectrum has become significantly crowded in latter years, with a possible saturation in the next decade, the integration of VLC system could significantly mitigate this problem.…”

Weak Calibration of a Visible Light Positioning System Based on a Position-Sensitive Detector: Positioning Error Assessment

“…Due to the deployment of LED lighting, more and more solutions are being developed that use visible light to both illuminate and communicate/transmit data (VLC—visible light communication) and positioning (visible light positioning) [ 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ].…”