SDN-controlled multi-user NOMA-OFDM VLC system based on a resource allocation algorithm

Area of Science:

• Optoelectronics and Photonics
• Wireless Communication Technologies
• Network Resource Management

Background:

• Visible Light Communication (VLC) systems offer high-speed wireless data transmission using LEDs.
• Non-Orthogonal Multiple Access (NOMA) enhances spectral efficiency in shared communication channels.
• Resource Allocation Algorithms (RAAs) are crucial for optimizing performance in multi-user systems.

Purpose of the Study:

• To introduce a novel Resource Allocation Algorithm (RAA) for multi-user NOMA-OFDM VLC systems.
• To address the limitation of conventional RAAs that prioritize users with stronger channel gains.
• To enhance system fairness and adaptability to dynamic user demands and channel conditions.

Main Methods:

• Developed a novel RAA for NOMA-OFDM VLC systems.
• Designed a software-defined-network (SDN)-controlled VLC system with real-time signal generation.
• Validated the RAA using a Field-Programmable Gate Array (FPGA)-based transmitter in experimental setups.

Main Results:

• The proposed RAA dynamically allocates bits based on the ratio of allocated to demanded bits, avoiding strong-user bias.
• Experimental results with a two-user NOMA-OFDM system achieved throughputs of 115-191 Mbit/s.
• The system demonstrated dynamic adaptation to changing data demands and user channel responses.

Conclusions:

• The novel RAA significantly outperforms conventional RAAs in NOMA-OFDM VLC systems.
• Performance benefits are consistent across varying data demands, receiving angles, and user distances.
• The proposed algorithm offers a more equitable and robust resource allocation strategy for VLC networks.