Demand-Aware Versus Fixed Mode-Group and Modulation-Format Assignment Strategies for Few-Mode Fiber Optical Networks

Few-Mode Fiber (FMF) networks based on Mode-Group Division Multiplexing (MGDM) introduce new challenges for dynamic resource allocation due to the trade-off between optical reach and transmission capacity across mode-group and modulation-format combinations. In this context, the Routing, Modulation, Mode-Group, and Wavelength Allocation (RMMWA) problem is affected by multidimensional resource overprovisioning under modal-spectral exclusivity constraints. This paper proposes a novel adaptive Demand-Aware Mode-Group and Modulation-Format Allocation (DA-MMA) strategy for MGDM-WDM optical networks and comparatively evaluates it against previously introduced reach-driven (RF-MMA) and capacity-driven (CF-MMA) strategies, as well as the perfect-fit baseline (BANG), under dynamic traffic conditions. Blocking probability and multidimensional overprovisioning are assessed across three representative topologies: UKNet, a length-extended UKNet, and a synthetic low-capacity 5-node network. Results show that performance is strongly topology-dependent. Capacity-driven prioritization achieves the largest blocking reduction in capacity-abundant networks, whereas in capacity-limited scenarios the proposed DA-MMA provides the best overall trade-off by jointly minimizing excess capacity and reach. When reach constraints dominate, performance differences narrow as physical feasibility becomes the primary limiting factor. Overall, no single allocation philosophy consistently provides the best performance; its effectiveness depends on the structural characteristics of the network.