Joint angle-diversity SDMA, OFDMA, and strict FFR framework for dense LiFi attocell networks

Area of Science:

• Optical Wireless Communications
• Wireless Networking
• Signal Processing

Background:

• Dense deployment of Light Fidelity (LiFi) and visible light communication (VLC) attocells exacerbates inter-cell interference.
• Existing studies on interference management techniques like angle-diversity transmitters (ADTs), orthogonal frequency-division multiple access (OFDMA), and fractional frequency reuse (FFR) lack a unified framework and consistent assumptions.
• This inconsistency hinders the accurate assessment of interference and resource sharing effects.

Purpose of the Study:

• To present a unified protocol-level framework for interference and resource management in dense LiFi networks.
• To integrate ADT-enabled space-division multiple access (SDMA), OFDMA, and strict FFR under a consistent modeling approach.
• To provide a reproducible benchmark for evaluating dense LiFi resource management strategies.

Main Methods:

• Development of a protocol-level framework unifying ADT-enabled SDMA, OFDMA, and FFR within a DCO-OFDM model.
• Classification of users into center and edge categories within macrocells served by multi-beam ADTs.
• Assignment of protected edge sub-bands using adjacency-aware graph coloring.
• Evaluation through 10,000-trial Monte Carlo simulations under full-load and random regimes, with sensitivity analysis on partitioning and user density.
• Inclusion of a dynamic extension with mobility, receiver orientation variation, non-line-of-sight (NLOS) modeling, and variable multi-user OFDMA admission.

Main Results:

• The unified framework achieves a mean Signal-to-Interference-plus-Noise Ratio (SINR) of approximately 28 dB in both simulated regimes.
• No outage was observed at 10 or 20 dB SINR thresholds in the finite line-of-sight (LOS) sample.
• The dynamic extension (OMN-PF) improved edge-frame service success over conventional PF, and OMN-PF-A further enhanced edge reliability with comparable spectral efficiency.

Conclusions:

• The proposed framework effectively unifies disparate interference and resource management techniques for dense LiFi networks.
• The simulation results demonstrate robust performance and reliability, even under dynamic conditions and mobility.
• This work establishes a valuable benchmark for future research and development in dense LiFi resource management.