Data Transport in an Integrated NGSO Satellite Communication and Radio Astronomy System



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An integrated mega-constellation non-geostationary orbit (NGSO) satellite communication and radio astronomy system (ISCRAS), was recently proposed in the literature as a new coexistence paradigm. We consider ISCRAS and focus on radio astronomical observation (RAO) data transport from the RAO-conducting satellites (called source satellites) to the ground gateways where each gateway is directly connected to a certain number of satellites (called destination satellites). This transportation of RAO data is an important problem and an existing work addressed it by applying a linear programming optimization based algorithm. However, the computational complexity of this algorithm is quite high which is exacerbated by the need to re-compute the algorithm frequently due to the time-varying characteristics of the RAO-conducting satellites, the Earth stations, and the RAO region. To address this high complexity issue, we develop a low-complexity RAO data transport algorithm. In addition to the static spectrum resource constraint scenario considered in the existing work, we introduce a dynamic spectrum resource constraint scenario to exploit the knowledge of the satellite communication system (SCS) traffic statistics. We also present a modified version of the optimization based algorithm in the literature for the dynamic resource constraint scenario. In addition to the number of inter-satellite link (ISL) hops as the RAO data transport cost metric, we also evaluate the metric of the sum of the squared ISL hop distances which reflects the transmission energy cost. Furthermore, computational complexity analysis and data transport costs of the algorithms are presented. Our results show that the proposed algorithm yields several orders of computational complexity saving over the existing method while incurring a modest increase in the data transport cost. Our proposed dynamic resource constraint scenario provides plausible reduction of the RAO data transport cost. Next, we introduce a generalized ISL connection model which extends the existing approach of adjacent-only ISL connections to include non-adjacent ISL connections. This model is implemented with an upper limit on the ISL distance which can be adjusted for performance tradeoffs. Next, we develop analytical expressions to study two impacts of satellite dynamics on the RAO data transport. The first one concerns with the beam misalignment of individual ISL hops. The second one corresponds to whether destination satellites move outside the gateway coverage during the end-to-end delay interval of a data packet transport. Furthermore, we introduce delay, energy, and spectrum usage performance metrics and evaluate them to yield performance tradeoff guidelines. A simplified data transport path model is also presented to facilitate analytical performance evaluation and initial system design settings. Then, we present a new RAO data transport design which incorporates system dynamics and desired performance tradeoffs.



Engineering, Electronics and Electrical