An Adaptive DCO-OFDM Scheme With Joint LED Selection and Waveform Design for Integrated Visible Light Positioning and Communication

Integrated visible light positioning and communication (VLPC) has been proposed to achieve both a high communication rate and accurate positioning. However, to integrate the visible light positioning (VLP) function, existing VLPC works typically suffer from a certain visible light communication (VLC) performance degradation. To address this issue, we propose an adaptive direct current-biased optical OFDM (ADCO-OFDM) scheme. In particular, we first design a novel waveform for ADCO-OFDM, which modulates the direct current (DC) bias of the VLC DCO-OFDM signal for positioning. Considering a practical system model with multi-LED and single photodetector (PD), the achievable rate of VLC and the Cramer-Rao Lower Bound (CRLB) for VLP are derived to analyze VLPC performance. Furthermore, to avoid the reverse effects of occlusions and obstacles, a joint LED selection and waveform design (J-LW) algorithm is proposed to optimize the VLPC performance. Specifically, the J-LW algorithm selects the most suitable LEDs for the VLPC system. Then, based on the selected LED subsets, a waveform optimization problem is formulated to simultaneously optimize communication and positioning precision. To solve the optimization problem, we prove the convexity of the optimization problem and solve it using convex optimization tools. Experiment results show that the proposed ADCO-OFDM can achieve up to 50% higher achievable rate and 72% lower CRLB values at most compared with the baseline models when the SNR is 22 dB.