Energy-efficient regeneration routing in satellite optical networks under translucent optical payload architectures.

The translucent optical payload architecture is most economical and feasible for optical switching in the satellite optical network (SON) using laser inter-satellite links (LISLs), where the wavelength division multiplexing (WDM) technology enables lightpaths to transparently pass through relay satellites, minimizing on-board processing. For the long-distance lightpath in SONs, lightpath regeneration is necessary to ensure the acceptable quality of transmission (QoT), where optical-electrical-optical (OEO) conversion causes non-negligible energy consumption. The rechargeable battery is an important component for low-earth-orbit (LEO) satellites, and unrestrained use batteries at a deep depth of discharge (DOD) will accelerate battery aging and shorten satellite lifetime, causing extremely high expenditure costs. How to improve energy efficiency in lightpath regeneration is a key problem in SONs, which has no related studies. This paper proposes energy-efficient regeneration routing (EE-RR) in SONs under translucent optical payload architectures, which is to reduce the battery life consumption of lightpath regeneration. We define the maximum bypass hops (MBH) to ensure the bit error rate (BER) requirement of lightpaths in SONs, considering the noise accumulation of amplifier spontaneous emission (ASE) and Doppler shift (DS) crosstalk. Two greedy baselines are proposed for EE-RR, which are the regeneration routing scheme minimizing the number of regeneration nodes (RRS-MRN) and the regeneration routing scheme minimizing single satellite's battery life consumption (RRS-MBL), respectively. Based on two greedy baselines, the regeneration routing scheme using genetic algorithms (RRSGA) is developed to improve the optimization ability of EE-RR. To our knowledge, this is the first study to propose taking battery aging into account in lightpath regeneration in SONs. Through numerical simulation, we find that blindly reducing the number of regeneration nodes in lightpaths may not reduce overall battery life consumption, and RRSGA can effectively reduce battery life consumption of lightpath regeneration in SONs.