Telecommunications
Babak Sadeghi; Seyed Mohammad Sajad Sadough
Abstract
This paper explores the integration of intelligent reflecting surfaces (IRS) with visible light communication (VLC) to enhance optical communication reliability and mitigate link blockage. We particularly focus on a patient vital signal monitoring system in a hospital, where a wireless optical device-to-device ...
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This paper explores the integration of intelligent reflecting surfaces (IRS) with visible light communication (VLC) to enhance optical communication reliability and mitigate link blockage. We particularly focus on a patient vital signal monitoring system in a hospital, where a wireless optical device-to-device (D2D) unit transmits signals to a monitoring center. Our study highlights the benefits of using an IRS, demonstrating that a 35-unit IRS array can double the received optical power compared to traditional non-line-of-sight (NLOS) links. We also propose an optimal placement strategy for IRS on indoor area walls to maximize the signal-to-noise ratio (SNR) and minimize the bit error rate (BER), considering constraints specific to optical wireless communication. We formulate and solve an optimization problem to determine the best IRS location, aimed at achieving ubiquitous communication with minimal BER. Numerical results illustrate the system's effectiveness in enhancing optical link reliability for patient monitoring. The findings indicate that optimal IRS placement can result in a BER as low as 2.48×10-8, and with adjustments to the photodetector orientation, an even lower BER of around 6.32×10-10 can be achieved without increasing transmitter power. This research underscores the potential of IRS in improving the performance of VLC systems, particularly in critical applications such as healthcare monitoring.
Telecommunications
Ali Eshkevari; Seyed Mohammad Sajad Sadough
Abstract
Direct Position Determination (DPD) is known as an optimal, single-step technique for localizing co-channel signal sources since it processes the data gathered from all the array receiver elements together. In contrast, the commonly used radio location techniques include two independent stages. First, ...
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Direct Position Determination (DPD) is known as an optimal, single-step technique for localizing co-channel signal sources since it processes the data gathered from all the array receiver elements together. In contrast, the commonly used radio location techniques include two independent stages. First, they estimate some initial parameters like direction, time, time-difference, frequency of arrival, etc., or their combination, and second, they localize signal sources using the triangulation of loci generated by the first stage. This disjoint structure leads to the sub-optimality of conventional localization algorithms. In this paper, we compare the Location root-mean-square-Error Lower Bounds (LELB) for DPD and position finding by DOA (PF-DOA) to prove the superiority of DPD over PF-DOA, which are commonly used for tactical fields or outdoor applications. Moreover, we demonstrate the advantages of DPD for indoor localization applications compared to PF-DOA techniques in terms of localization accuracy. We also introduce the single-group-array (SGA) structure for DPD in indoor applications and reveal that it outperforms both the PF-DOA and DPD with a classical multi-group-array (MGA) structure.