Joint design of ordered QR precoding and SIC detection for MIMO VLC systems

Area of Science:

• Electrical Engineering
• Optical Communications
• Signal Processing

Background:

• Multiple-Input Multiple-Output (MIMO) systems in Visible Light Communication (VLC) face challenges with high spatial correlation.
• Existing Ordered Successive Interference Cancellation (OSIC) schemes for MIMO VLC exhibit high computational complexity due to repeated reordering and matrix inversions.

Purpose of the Study:

• To propose a joint design of ordered QR decomposition precoding and Successive Interference Cancellation (SIC) detection (OQR-SIC) for MIMO VLC systems.
• To reduce detection complexity and mitigate spatial correlation issues in MIMO VLC systems.
• To optimize system data rate through channel matrix ordering and power allocation under practical constraints.

Main Methods:

• Developed an OQR-SIC scheme utilizing QR decomposition to obtain an upper triangular matrix for sequential symbol detection without reordering or matrix inversion.
• Optimized the ordering of channel matrix columns prior to QR decomposition.
• Implemented power allocation strategies considering dimming control, total electrical power, and reliable SIC detection.

Main Results:

• The OQR-SIC scheme successfully reduces detection complexity compared to conventional QR-SIC.
• Achieved significant signal-to-noise ratio (SNR) gains: 2 dB for 4x4 and 9.8 dB for 9x9 MIMO VLC systems at a bit error rate (BER) of 10^-3.
• Demonstrated improved system data rates through optimized precoding and power allocation.

Conclusions:

• The proposed OQR-SIC offers a computationally efficient and high-performance solution for MIMO VLC systems.
• This joint precoding and detection design effectively addresses spatial correlation and enhances SNR.
• The optimization of channel ordering and power allocation further boosts system data rates under realistic operational constraints.