NOMA-Integrated Interleave-Division Multiple Access: A Beyond 5G Perspective

Efficient multiple access is vital for spectrum-constrained, user-dense IoT networks. This study joins interleave-division multiple access (IDMA) with power-domain non-orthogonal multiple access (NOMA) and employs ordered successive-interference-cancellation multi-user detection (SIC-MUD). Unequal power allocation and orthogonal interleavers let all users share one spreading code while keeping chip-level complexity low. Simulations of a five-user uplink and a thirty-two-user downlink show that the worst user attains a bit-error rate of 1.4 × 10⁻³ at 10 dB, needing ≈ 3 dB less SNR than equal-power IDMA; flat Rayleigh fading raises the curve by only ≈ 2 dB. A software detector processes 2048-bit frames in ≈ 0.03 s on a standard desktop, and cycle estimates predict under 5 ms latency on a 32-100 MHz FPGA. Random interleaving gives the lowest error rate, while master-random and tree-based patterns lose < 0.3 dB yet cut memory sharply. Ordered SIC-MUD NOMA-IDMA thus offers concrete performance gains and real-time feasibility for dense 6G and massive-IoT deployments.