Frequency assignment in a SDMA satellite communication system with beam decentring feature

Abstract

International audienceIn satellite communication, Spatial Division Multiple Access (SDMA) has become one of the most promising techniques that can accommodate continuing increase in the number of users and traffic demands. The technology is based on radio resource sharing that separates communication channels in space. It relies on adaptive and dynamic beam-forming technology and well-designed algorithms for resource allocation among which frequency assignment is considered. This paper studies static Frequency Assignment Problem (FAP) in a satellite communication system involving a satellite and a number of users located in a service area. The objective is to maximize the number of users that the system can serve while maintaining the signal to interference plus noise ratio of each user under a predefined threshold. Traditionally, interference is treated as fixed (binary interferences or fixed minimal required separation between frequencies) . In this paper, the interference is cumulative and variable. To solve the problem, we work on both discrete and continuous optimizations. Integer linear programming formulations and greedy algorithms are proposed for solving the discrete frequency assignment problem. The solution is further improved by beam decentring algorithm which involves continuous adjustment of satellite beams and deals with non-linear change of interference

Linearization of Euclidean norm dependent inequalities applied to multibeam satellites design

“…From the point of view of our application, solving this optimization problem can be interpreted as finding the most isotropic treatment of all the R 3 directions before approximating linearly the Euclidean distances. Let therefore U be an optimal (or suboptimal) solution of (14), then Proposition 1 and Proposition 2 become valid in R 3 simply by using U as the set of discretized directions and by setting θ max = J (U).…”

“…Since the application that motivated this work (beam layout optimization, detailed further in the article) is set in the Euclidean plane, we did not perform at this point any analysis for R 3 similar to the one presented in the previous paragraph for R 2 where the evolution of the approximation error with the number of discretized direction has been properly quantified. To do so, one would simply have to implement a solution for solving (14) for each number of directions n directions tested.…”

“…Another example in the satellite industry is the problem of optimizing the beam layouts of a multibeam telecommunication satellite system (see [5], [6] and [14] for instance). It consists of defining the positions in the Euclidean plane of a certain number of disks, each one representing the spatial extent of a radiofrequency beam that carries telecommunication signals for various applications: television, telephone, radio or internet by satellite for instance.…”

MILP formulation improvement with k-means clustering for the beam layout optimization in multibeam satellite systems

“…Because of the increasing demand in various data exchanges, there has been a significant amount of research devoted to performance improvement of such systems, as reviewed in [22], such as the use of optical link techniques [19], the coordination of two co-localized satellites [7] or the design of multibeam array antennas [21]. The literature on solution approaches for power and frequency allocation problems is rather rich [18,11,12,23,24,1,14,10]. However, papers dealing with beam layout algorithms are not frequently published.…”

Mixed-integer linear programming for multibeam satellite systems design: Application to the beam layout optimization

“…Some research papers focus exclusively on one of the satellite subsystems: for instance, the authors of [12] investigate algorithms to optimize the design of multibeam array antennas. For a given system architecture and a given satellite payload, literature is also rich on the question of how to optimize the allocation of resources such as the satellite power and the system bandwidth: [9], [6], [7], [14] and [11] for instance. On the other hand, the stress is rarely put on the strong interdependencies of all the subsystems of a multibeam satellite system in the design phase.…”