A Self-Adaptive Primary-Band Priority Algorithm Considering Nonlinear Interference in C+L+S-Band Optical Networks

Continued growth in traffic demands and dynamic behavior needs more flexible technologies in elastic optical networks (EONs). These technologies are used to expand capacity and provide high-speed communications with guaranteed quality of service (QoS). Multi-band (MB) has attracted increasing attention as a medium-term solution to increase the available spectrum range with other bands. However, the multi-band technology also poses a challenge when resolving network capacity issues. It exacerbates the power transfer from higher-frequency to lower-frequency channels introduced by stimulated Raman scattering (SRS) among requests that were initially neglected in a single band. And SRS-induced power transfer greatly impacts the transmission quality of multi-band networks. Therefore, it is necessary to consider the accumulation of nonlinear interference (NLI) in multi-band request allocation. In this paper, we study the routing, band and spectrum assignment (RBSA) problem in C+L+S-band optical networks to improve the request signal-to noise ratio (SNR) in multi-band networks through a more flexible traffic allocation method. We propose an adaptive primary-band priority algorithm. By evaluating the changes in nonlinear interference across the network using statistical methods, we adaptively choose the primary band from C, L or S band at different moments and prioritize the request allocation to the primary band. We also propose a mathematical model considering NLI and SNR analysis to describe the problem more clearly. And based on this, a heuristic algorithm based on genetic algorithm (GA) is proposed. We evaluate the performance of the proposed method through experimental simulations. The results indicate that prioritizing the allocation of primary band in the C+L+S band scenario is beneficial. Adaptive adjustment of the current primary band based on real-time network conditions proves effective. These measures successfully reduce the accumulation of NLI in the network and improve the overall SNR.