Multiservice traffic allocation in LEO satellite communications (original) (raw)
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This paper proposes an heuristic for the scheduling of capacity requests and the periodic assignment of radio resources in geostationary (GEO) satellite networks with star topology, using the Demand Assigned Multiple Access (DAMA) protocol in the link layer, and Multi-Frequency Time Division Multiple Access (MF-TDMA) and Adaptive Coding and Modulation (ACM) in the physical layer. The objective is to design an algorithm that allows processing a given traffic profile with packet expiration time as delay constraints and a maximum packet loss rate, using the minimum possible spectrum bandwidth. When there is not any structure imposed to the MF-TDMA super-frame, the resourceassignment problem becomes a combinatorial problem which can be seen as a two-dimension (2D) oriented strip packing problem with additional constraints. The well-known Best Fit Decreasing Height (BFDH) heuristic for 2D packing is used as a basis for the proposed allocation algorithm, which should be able to obtain a set of candidate solutions in the order of a few hundredths of milliseconds. Later it is proposed to randomize and parallelize the heuristic in order to produce several candidate solutions, among which to select the optimum, which is the one that minimizes the overall bandwidth consumption.
A Heuristic Algorithm for the Resource Assignment Problem in Satellite Telecommunication Networks
This paper proposes a heuristic algorithm for solving the scheduling of capacity requests and the periodic assignment of radio re-sources in a geostationary satellite network with a star topology. The network uses the Demand Assigned Multiple Access protocol in the link layer, and the Multi-Frequency Time Division Multiple Access (MF-TDMA) as well as the Adaptive Coding and Modulation protocols in the physical layer. The proposed algorithm allows processing a given traffic profile with message expiration time as delay constrains and a maximum packet-loss rate. The processing is completed using the minimum possible spectrum bandwidth. When there is not any structure imposed to the MF-TDMA super-frame, the resource-assignment problem becomes a combinatorial optimization problem which can be seen as a two-dimension (2D) oriented strip packing problem with additional constrains. The well-known Best Fit Decreasing heuristic for 2D packing is used as a basis for the proposed allocation al...
Wireless Networks, 2004
The Up/Down Link UDL of a Low Earth Orbit LEO satellite constellation is a scarce radio resource that needs to be shared efficiently between many users with different needs. A suitable Connection Admission Control (CAC) policy is required. In our study we assume that the network handles three types of calls: real time (voice) calls with strict constraints over the delay and over the bandwidth, non-real time (data) calls delay tolerant but with bandwidth guarantees requirements and Best Effort calls with no guarantees requirements. In order to ensure priorities are respected, two mechanisms are considered: an "enhanced extended trunk reservation policy", as well as a combination of trunk reservation with priority scheduling in order to derive the Resources Allocation RA. A differentiated RA scheme is proposed, associated with queuing for the lower priority calls. Different unit bandwidths are associated with calls depending on their requirements. The analytical Markovian models for both the differentiated and the non-differentiated trunk reservation systems are first derived, under simplified hypothesis, in order to point out the advantages of the differentiated RA choice. Then, the model for another RA scheme, the combined differentiated trunk reservation/priority scheduling, is also analytically solved under Markovian hypothesis for the different traffic classes. The performance of the two more general versions of the RA techniques thus solved are compared using simulation. Impact of non-Markovian laws is also studied using simulation.
Resource management in satellite communication systems — Heuristic algorithms
The high cost of frequency bandwidth in satellite communication emphasizes the need for good algorithms to cope with the resource allocation problem. In systems using DVB-S2 links, the optimization of resource allocation may be related to the classical multi-knapsack problem. Resource management should be carried out according to the requests of subscribers, their priority levels, and assured bandwidths. A satisfaction measure is defined to estimate the allocation processes. Heuristic algorithms together with some innovative scaling schemes are presented and compared using Monte Carlo simulation based on a traffic model introduced here.
Static and dynamic resource allocation in a multiservice satellite network with fading
International Journal of Satellite Communications and Networking, 2003
A control architecture for resource allocation in satellite networks is proposed, along with the specification of performance indexes and control strategies. The latter, besides being based on information on traffic statistics and network status, rely upon some knowledge of the fading conditions over the satellite network channels. The resource allocation problem consists of the assignment, by a master station, of a total available bandwidth among traffic earth stations in the presence of different traffic types. Traffic stations are assumed to measure continuously their signal fade level, but this information may either be used only locally or also communicated to the master station. According to the information made available on-line to the master station on the level of the fading attenuation of the traffic stations, the assignment can be made static, based on the a priori knowledge of long-term fading statistics, or dynamic, based on the updated measurements. In any case, the decisions can be adapted to slowly time-varying traffic characteristics. At each earth station, two basic traffic types are assumed to be present, namely guaranteed bandwidth, real-time, synchronous data (stream traffic), and best effort traffic (datagram traffic). Numerical results are provided for a specific architecture in the dynamic case, in a real environment, based on the Italsat satellite national coverage payload characteristics.
Scalable Proportional Bandwidth Allocation in Satellite Networks
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Abstract Future satellite communication systems proposed use geosynchronous (GEO) satellites, medium earth orbit (MEO), and low earth orbit (LEO) constellations with fast packet switching and quality of service (QoS) provisioning. In this paper, we present broadband GEO, MEO and LEO satellite network QoS models and simulated performance results. This paper proposes a new method of bandwidth allocation during congestion, called the proportional allocation of bandwidth (PAB).
Routing in Low Earth Orbit Satellite Systems Based on the Optimization
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Since the satellites become more common for today's communication area, the process and the improvements in the satellite networks are gaining importance. One of the challenges in satellite networks is the routing operation between two end nodes, because, these networks have dynamic changing satellite movements. During these movements, a satellite can give its coverage area service order to one of its neighboring satellites. Also some calls can be blocked when the call densities exceed the communication link's capacities or the signals interfere with each other. All of these situations make the routing operation quite complicated. In this study, we design a new routing algorithm for Low-earth orbit (LEO) satellite systems. We use dynamic satellite topologies containing different number of nodes. We apply the genetic algorithms during the optimization steps. We introduce a new objective function including the delay and the aging factor as the characteristic properties of the paths. Finally, we compare the paths with each other and select the optimal path having the best fitness value.
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We propose an approach to optimize resource sharing and flow control in a multi-beam broadband satellite system that supports both unicast and multicast flows. We show that, in this architecture, the load on every spot-beam queue could be different, depending on the type of the flows and the distribution of the receivers across spot-beam coverage areas. This load imbalance may significantly under-utilize the system resources and decrease the system throughput when both unicast and multicast flows are active in the system. In this paper, we formulate an optimization problem for intra-and inter-beam resource sharing such that the variance of the session rates experienced by users of a flow located in different beam coverage areas is minimized. The result of our resource allocation also determines the maximum sustainable rate of each flow. We present results that compare the beam utilization and maximum sustainable sessions rates with and without optimization. We conclude that this method improves the average session rates up to 40% and average utilization of the system up to 15% when both unicast and multicast flows are active.
Dynamic capacity allocation for quality-of-service support in ip-based satellite networks
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