Resource allocation optimization in TFDM-based flexible-rate simplified coherent PON.

Area of Science:

• Optical Communications
• Signal Processing
• Network Engineering

Background:

• Passive Optical Networks (PONs) are crucial for broadband access.
• Cost reduction and performance enhancement in PONs are ongoing challenges.
• Coherent detection offers high performance but increases Optical Network Unit (ONU) costs.

Purpose of the Study:

• To propose a mathematical model and algorithm for optimizing diversity gain in a simplified coherent PON.
• To reduce the cost of ONUs in a flexible-rate Time and Frequency-Division Multiplexing (TFDM) system.
• To evaluate the performance of the proposed TFDM scheme for high-speed downstream transmission.

Main Methods:

• Developed a mathematical model incorporating entropy loading and a solving algorithm.
• Implemented Alamouti coding at the Optical Line Terminal (OLT).
• Restricted each ONU to receive a single subcarrier to minimize system costs.

Main Results:

• The proposed TFDM scheme demonstrated marginal sensitivity of Net Data Rate (NDR) to the number of subcarriers at 100 Gb/s.
• Increased subcarrier usage significantly reduced the bandwidth requirement on the ONU side.
• TFDM maintained diversity gain and achieved 13.47 Gb/s higher NDR than Time-Division Multiplexing (TDM) under varying link conditions.

Conclusions:

• The proposed TFDM scheme offers a cost-effective solution for future passive optical networks.
• TFDM provides significant performance benefits, including higher NDR and reduced ONU bandwidth requirements.
• The system effectively maintains diversity gain, crucial for reliable optical communication.