6 research outputs found
Radio Resource Management Techniques for Multibeam Satellite Systems
Next-generation of satellite communication (SatCom) networks are expected to
support extremely high data rates for a seamless integration into future large
satellite-terrestrial networks. In view of the coming spectral limitations, the
main challenge is to reduce the cost per bit, which can only be achieved by
enhancing the spectral efficiency. In addition, the capability to quickly and
flexibly assign radio resources according to the traffic demand distribution
has become a must for future multibeam broadband satellite systems. This
article presents the radio resource management problems encountered in the
design of future broadband SatComs and provides a comprehensive overview of the
available techniques to address such challenges. Firstly, we focus on the
demand-matching formulation of the power and bandwidth assignment. Secondly, we
present the scheduling design in practical multibeam satellite systems.
Finally, a number of future challenges and the respective open research topics
are described.Comment: Submitted to IEEE Communications Letter
JOINT CARRIER ALLOCATION AND PRECODING OPTIMIZATION FOR INTERFERENCE-LIMITED GEO SATELLITE
The rise of flexible payloads on satellites opens a door for controlling satellite resources according to the user demand, user location, and satellite position. In addition to resource management, applying precoding on flexible payloads is essential to obtain high spectral efficiency. However, these cannot be achieved using a conventional resource allocation algorithm that does not consider the user demand. In this paper, we propose a demand-aware algorithm based on multiobjective optimization to jointly design the carrier allocation and precoding for better spectral efficiency and demand matching with proper management of the satellite resources. The optimization problem is non-convex, and we solve it using convex relaxation and successive convex approximation. Then, we evaluate the performance of the proposed algorithm through numerical results. It is shown that the proposed method outperforms the benchmark schemes in terms of resource utilization and demand satisfaction
Secure Satellite Communication Systems Design with Individual Secrecy Rate Constraints
In this paper, we study multibeam satellite secure communication through
physical (PHY) layer security techniques, i.e., joint power control and
beamforming. By first assuming that the Channel State Information (CSI) is
available and the beamforming weights are fixed, a novel secure satellite
system design is investigated to minimize the transmit power with individual
secrecy rate constraints. An iterative algorithm is proposed to obtain an
optimized power allocation strategy. Moreover, sub-optimal beamforming weights
are obtained by completely eliminating the co-channel interference and nulling
the eavesdroppers' signal simultaneously. In order to obtain jointly optimized
power allocation and beamforming strategy in some practical cases, e.g., with
certain estimation errors of the CSI, we further evaluate the impact of the
eavesdropper's CSI on the secure multibeam satellite system design. The
convergence of the iterative algorithm is proven under justifiable assumptions.
The performance is evaluated by taking into account the impact of the number of
antenna elements, number of beams, individual secrecy rate requirement, and
CSI. The proposed novel secure multibeam satellite system design can achieve
optimized power allocation to ensure the minimum individual secrecy rate
requirement. The results show that the joint beamforming scheme is more
favorable than fixed beamforming scheme, especially in the cases of a larger
number of satellite antenna elements and higher secrecy rate requirement.
Finally, we compare the results under the current satellite air-interface in
DVB-S2 and the results under Gaussian inputs.Comment: 34 pages, 10 figures, 1 table, submitted to "Transactions on
Information Forensics and Security
Power and bandwidth allocation in multibeam satellite systems
This thesis proposes a genetic algorithm to allocate the main resources of a multibeam communications satellite: power and bandwidth. The algorithm exposed can reduce the unmet system capacity (USC) by 10% - 15% in comparison with a power-only allocation