NOMA Spectrum Assignment + PSO-based Power Optimization

Assign the spectrum using power-domain NOMA on OFDM subcarriers and uses a Particle Swarm Optimization (PSO)

• Simulates an OFDM system with Rayleigh fading and distance-based pathloss.
• On each subcarrier, it pairs the weakest and strongest user (classic NOMA pairing).
• Uses PSO (implemented from scratch—no toolboxes needed) to:
• Allocate total power across subcarriers (gamma_n, normalized),
• Choose the weak/strong split per subcarrier (beta_n with a lower bound beta_min for the weak user).
• Objective balances pure throughput (sum-rate) and proportional fairness: tune lambda between 0 and 1.

Compares against:

• Equal-power NOMA with fixed beta,
• OMA (one user per subcarrier—the best one).