Integrated visible light communication and positioning CDMA system employing modified ZCZ and Walsh code

Area of Science:

• Optical Communications
• Wireless Positioning Systems
• Multiple Access Techniques

Background:

• Visible Light Communication (VLC) offers high bandwidth potential.
• Simultaneous communication and positioning is crucial for intelligent systems.
• Code Division Multiple Access (CDMA) enables multiple users to share a common channel.

Purpose of the Study:

• To propose an integrated Visible Light Communication and Positioning (VLCP) system using CDMA.
• To develop a generalized modification method for balanced bipolar code sets for intensity modulation.
• To evaluate the performance of modified Zero Correlation Zone (ZCZ) and Walsh code sets in VLCP-CDMA systems.

Main Methods:

• A generalized modification method for balanced bipolar code sets was developed.
• Modified Zero Correlation Zone (ZCZ) and Walsh code sets were employed in the VLCP-CDMA system.
• System simulations and experiments were conducted for synchronous and quasi-synchronous (QS) scenarios.

Main Results:

• The modified ZCZ code set demonstrated superior communication and positioning performance compared to the modified Walsh code set.
• A bit error rate (BER) of 1.8×10^-3 was achieved.
• An average positioning error of 1.50 cm was obtained in a 4-user real-time system.

Conclusions:

• The proposed VLCP-CDMA system effectively integrates communication and positioning functionalities.
• Modified ZCZ code sets provide an optimal solution for enhanced VLCP-CDMA performance.
• This integrated system presents a promising solution for future intelligent systems requiring simultaneous communication and positioning.