A study on dynamic spectrum assignment for fairness in elastic optical path networks

The elastic optical path network, which enables efficient spectrum utilization of optical fibers by combining frequency slots with fine granularity and flexible bandwidth providing for each optical connection, has been attracting much attention. In elastic optical path networks, the modulation format is decided depending on the transmission distance of each optical connection. Long hop connections require many frequency slots. Moreover, we must search for availability in many links for long hop connections. Because of these two properties, long hop connections are more likely to be blocked. To solve this unfairness problem, we propose a new spectrum assignment method that divides the frequency bandwidth into prioritized bands for each connection grouped by its number of hops and dynamically controls the width of the prioritized bands depending on the blocking probabilities. Our proposed method is able to improve fairness significantly, which is confirmed by computer simulations. Moreover, we verify that our proposed method is also able to set each blocking probability individually.