China Launches Its First High-Throughput Communications Satellite

China launched the SJ-13(ChinaSat-16)satellite at 7:04 p.m.on April12 on a LM-3B carrier rocket from the Xichang Satellite Launch Center.The satellite was developed by the China Academy of Space Technology(CAST)with a design lifetime of 15 years.SJ-13,China’s first high-throughput communications satellite that applies electric propulsion technology,is the first satellite based on the DFH-4S platform and will conduct high speed laser communications tests for the first time in China.

Joint Precoding Schemes for Flexible Resource Allocation in High Throughput Satellite Systems Based on Beam Hopping

Beam hopping technology provides a foundation for the flexible allocation and efficient utilization of satellite resources,which is considered as a key technology for the next generation of high throughput satellite systems.To alleviate the contradiction between resource utilization and co-frequency interference in beam hopping technology,this paper firstly studies dynamic clustering to balance traffic between clusters and proposes cluster hopping pool optimization method to avoid inter-cluster interference.Then based on the optimization results,a novel joint beam hopping and precoding algorithm is provided to combine resource allocation and intra-cluster interference suppression,which can make efficient utilization of system resources and achieve reliable and near-optimal transmission capacity.The simulation results show that,compared with traditional methods,the proposed algorithms can dynamically adjust to balance demand traffic between clusters and meet the service requirements of each beam,also eliminate the co-channel interference to improve the performance of satellite network.

Performance Assessment of Coded-Beam High Throughput Satellites

High-throughput satellite (HTS) systems usually make use of Multibeam coverage at high frequency bands in order to offer broadband access of large areas. Multibeam coverage increases the available capacity through frequency reuse and spatial separation. However, one of its major drawbacks is inter- spot interference which considered the motivation to propose a new approach using a coding technique to distinguish between beams that will be employed to mitigate this interference without the need of frequency reuse. This approach makes the use of orthogonal codes to identify beams and allow using the total satellite bandwidth per beam. Proposed system double the bandwidth used in each beam and save the usage of antenna polarization resource used in former designs, which may be used as a multiple accessing resource inside the coded beams. The objective of this paper is to provide a comprehensive performance assessment methodology for the proposed approach. Result validation is introduced by comparing the proposed system performance with conventional systems that relay on the DVB standards.

Power Allocation Optimization of Multibeam High-Throughput Satellite Communication Systems

The increasing demands in terms of high data rate and quality of services over the hybrid satellite-terrestrial relay networks(HSTRN)have pushed for the development of millimeter-wave(mmWave)band high-throughput satellites(HTS)with multibeams.The next generation of mmWave multibeam HTS communication systems(HTSCS)is viewed as the backbone network to enhance the throughput of the HSTRN.The article first investigates the basic backbone topology architecture of HTSCS,and an M-state Markov channel for the Ka/Q/V band mmWave systems is reviewed.Then,we propose a long-term optimal power allocation scheme over two in-dependent and identical spot beams based on the partially observable Markov decision process(POMDP),which can partly mitigate the negative effects of severe weather conditions.The key conditions for selecting the optimal power allocation action in the multibeam HTSCS are given.Simulation results show that our POMDP-based power allocation scheme can enhance the long-term throughput of the HTSCS.