On the use of bandwidth limited pulses to implement multilevel modulation in optical camera communication systems

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master_Huang_Zhongtian_2025.pdf (5.17 MB)

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School of Electrical Engineering | Master's thesis
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Date

2025-07-03

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Major/Subject

Communications Engineering

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Degree programme

Master's Programme in Computer, Communication and Information Sciences

Language

en

Pages

62

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Abstract

Optical Camera Communication (OCC) has emerged as a cost-effective and flexible solution for wireless data transmission, leveraging widely available camera sensors as receivers of visible light signals. However, the prevalent use of rolling shutter mechanisms in CMOS sensors introduces significant challenges such as synchronization issues and inter-symbol interference (ISI), especially in high data rate communication scenarios. This report investigated the application of Square Root Raised Cosine (SRRC) filters for pulse shaping at the transmitter side and matched filtering at the receiver side, aiming at mitigating these challenges. By employing SRRC filters, ISI was reduced and the synchronization was improved, enhancing the reliability and data rate of the OCC systems. The experimental setup relied on an Ettus USRP N210 in transmission and an Alvium 1800 U-500 rolling shutter camera in reception, and the end-to-end performance of the system was evaluated at varying transmission distances and exposure times. Results demonstrated that SRRC-based filtering significantly lowers the bit error rate (BER), particularly under conditions of short transmission distances and optimized exposure times. This MSc Thesis highlighted the effectiveness of bandwidth-limited pulse shaping in improving OCC system performance and provided insights for future system design and optimization.

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Supervisor

Hämäläinen, Jyri

Thesis advisor

Dowhuszko, Alexis

Keywords

optical camera communication, rolling shutter, square root raised cosine filter, pulse shaping, multi-level modulation, demodulation

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https://urn.fi/URN:NBN:fi:aalto-202508196369

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[dipl] Sähkötekniikan korkeakoulu / ELEC