We revisit spectrum allocation (SA), a fundamental problem in optical network design, and we explain that it can be modeled as a permutation problem. This new model eliminates spectrum symmetry, a property that presents a significant challenge to conventional spectrum allocation solutions. Accordingly, we develop parameterized first-fit (PFF), a new symmetry-free heuristic for the SA problem that has several desirable features: it explores a pre-defined subset of the solution space whose size is tailored to the available computational budget; it constructs this subset by sampling from diverse areas of the solution space rather than from the neighborhood of an initial solution; it finds solutions by applying the well-known first-fit (FF) algorithm and thus it can be deployed readily; its execution can be easily parallelized; and it is effective and efficient in finding good quality solutions.

我们重新审视频谱分配 (SA)，这是光网络中的一个基本问题设计，我们解释说它可以建模为排列问题。这种新模型消除了频谱对称性，这一特性对传统的频谱分配解决方案提出了重大挑战。因此，我们开发了参数化首次拟合 (PFF)，这是一种针对 SA 问题的新的无对称启发式算法，它具有几个理想的特征：它通过从解空间的不同区域而不是从初始解的邻域采样来构建这个子集；它通过应用著名的首次拟合 (FF) 算法找到解决方案，因此可以轻松部署；它的执行可以很容易地并行化；它在寻找高质量的解决方案方面是有效和高效的。