Beam Coverage Comparison of LEO Satellite Systems Based on User Diversification (original) (raw)
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Performance Analysis of LEO Satellite Networks
Lecture Notes in Computer Science, 2002
We present an analytical model for computing call blocking probabilities in a LEO satellite network that carries voice calls. Both satellite-fixed and earth-fixed constellations with inter-orbit links and hand-offs are considered. The model is analyzed approximately by decomposing it into sub-systems. Each sub-system is solved in isolation exactly using a Markov process, and the individual results are combined together through an iterative method. Numerical results demonstrate that our method is accurate for a wide range of traffic patterns.
Performance of Low Earth Orbit Satellite Systems with a Gaussian Mixtures Traffic Distribution
A new traffic model for Low Earth Orbit (LEO) Satellite system is proposed. Two different cases are considered. The first case represents the situation in which the traffic load follows a bimodal contaminated Gaussian distribution. The second case considers the trimodal distribution. The parameters of this new distribution model are introduced and their effects on the Signal to Interference Ratio (SIR) and the capacity are investigated. KEYWORDS Low Earth Orbit Satellite Communication I. INTRODUCTION Low earth orbit satellite communication systems are one of the most appropriate systems to offer personal communications (PC) [1-3]. They can also provide additional advantages for the global communication networks, e.g., small propagation delay and loss, and high elevation angle in high latitude [4]. One of the most recent candidates for establishing the multiple access in LEO satellite systems is Code Division Multiple Access (COMA). CDMA has higher capacity than TDMA and FDMA if voice activity and frequency reuse by spatial isolation are employed [5]. The non-uniform distribution of the traffic is a normal feature of our globe. However there are only few studies on the effect of this nonuniformity of the traffic on the performance of LEO systems. Performance analysis of
International Journal of Satellite Communications, 1999
A real time simulation study for the evaluation of traffic flow in low earth orbit (LEO) satellite constellations, used for the interconnection of high-speed networks, is presented in this paper. The proposed model simulates end to end the traffic process at the packet level, supporting successfully the implementation of self-similar traffic sources , a modeling approach that has been considered more realistic than the well-known Poisson, for real-time communications. An in-depth study for the establishment of inter-satellite links (ISLs) and the design of the terrestrial and space segments is presented and the performance of the integrated system is evaluated in terms of delay and throughput parameters.
Generalized performance evaluation of low Earth orbit satellite systems
IEEE Communications Letters, 2000
A novel three-dimensional distribution traffic is proposed for Low Earth Orbit (LEO) satellite systems. The effect of the traffic geographical nonuniformity on the performance of these satellite systems is discussed. Index Terms-3-D model, LEOS, traffic measurements.
Network planning, analysis and design are an iterative process aimed at ensuring that a new network service meets the needs of subscribers and operators. During the initial start-up phase, coverage is the big issue and coverage in telecommunications systems is related to the service area where a bare minimum access in the wireless network is possible. In order to guarantee visibility of at least one satellite above a certain satellite elevation, more satellites are required in the constellation to provide Global network services. Hence, the aim of this paper is to develop wide area network coverage for sparsely distributed earth stations in the world. A hybrid geometrical topology model using spherical coordinate framework was devised to provide wide area network coverage for sparsely distributed earth stations in the world. This topology model ensures Global satellite continuous network coverage for terrestrial networks. A computation of path lengths between any two satellites put in place to provide network services to selected cities in the world was carried out. A consideration of a suitable routing decision mechanism, routing protocols and algorithms were considered in the work while the shortest paths as well as the alternate paths between located nodes were computed. It was observed that a particular satellite with the central angle of 27° can provide services into the diameter of the instantaneous coverage distance of 4081.3 Km which is typical of wide area network coverage. This implies that link-state database routing scheme can be applied, continuous global geographical coverage with minimum span, minimum traffic pattern and latency are guaranteed. Traffic handover rerouting strategies need further research. Also, traffic engineering resources such as channel capacity and bandwidth utilization schemes need to be investigated. Satellite ATM network architecture will benefit and needs further study.
Satellite Network Performance Measurements Using Simulated Multi-User Internet Traffic
1999
As a number of diverse satellite systems (both Low Earth Orbit and Geostationary systems) are being designed and deployed, it becomes increasingly important to be able to test these systems under realistic traffic loads. While software simulations can provide valuable input into the system design process, it is crucial that the physical system be tested so that actual network devices can be employed and tuned. These tests need to utilize traffic patterns that closely mirror the expected user load, without the need to actually deploy an end-user network for the test. In this paper, we present trafgen. trafgen uses statistical information about the characteristics of sampled network traffic to emulate the same type of traffic over the test network. This paper compares sampled terrestrial network traffic with emulated satellite network traffic over the NASA ACTS satellite.
Analysis of system parameters for LEO/ICO-satellite communication networks
IEEE Journal on Selected Areas in Communications, 1995
Currently many efforts are undertaken to develop and install communication networks based on low earth orbit (LEO) and intermediate circular orbit (ICO) satellites. However, many problems are to be solved until the final operation of such networks. This paper deals with basic design problems of LEODCO-based networks. In the first part, the topology of the satellite network is considered and estimates for the necessary number of satellites, orbits and number of communication channels per satellite are derived. Features and consequences of intersatellite links are discussed. In the second part of the paper, the number of communication channels per link is derived with a more elaborate model. This includes the radio links from the satellites to mobile users and to gateways, as well as intersatellite links and terrestrial lines. We introduce a formal model for LEO/ICO-based networks and propose a method for the evaluation of link capacities, given the network topology and the trafflc requirements. As an example, two constellations are investigated in detail. One of these constellations is the Iridium system proposed by Motorola, the other one is the LEONET concept developed in an ESA study. Finally, the influence of unequal traffic distribution is discussed.
Stochastic Geometry-Based Analysis of LEO Satellite Communication Systems
IEEE Communications Letters, 2021
This letter studies the performance of a low-earthorbit (LEO) satellite communication system where the locations of the LEO satellites are modeled as a binomial point process (BPP) on a spherical surface. In particular, we study the user coverage probability for a scenario where satellite gateways (GWs) are deployed on the ground to act as a relay between the users and the LEO satellites. We use tools from stochastic geometry to derive the coverage probability for the described setup assuming that LEO satellites are placed at n different altitudes, given that the number of satellites at each altitude a k is N k where 1 ≤ k ≤ n. To resemble practical scenarios where satellite communication can play an important role in coverage enhancement, we compare the performance of the considered setup with a scenario where the users are solely covered by a fiber-connected base station (referred to as anchored base station or ABS in the rest of the paper) at a relatively far distance, which is a common challenge in rural and remote areas. Using numerical results, we show the performance gain, in terms of coverage probability, at rural and remote areas when LEO satellite communication systems are adopted. Finally, we draw multiple system-level insights regarding the density of GWs required to outperform the ABS, as well as the number of LEO satellites and their altitudes.
Multiservice traffic allocation in LEO satellite communications
2006
Satellite communication promises potential methods for providing global communication. In particular, by the development of a Low Earth Orbital (LEO) satellite constellation, both global coverage and broadband communication will be accessible. Problems arise in situations where various tra¢ c types in broadband communication require di¤erent levels of quality of service (QoS). Tra¢ c control is required to make sure that each tra¢ c demand may receive the expected QoS. Another problem is that the dynamic topology of a LEO satellite network requires a tra¢ c allocation control, which is able to allocate tra¢ c demand into the Inter Satellite Links (ISLs) between LEO satellites. In this thesis, tra¢ c allocation strategy in a dynamic LEO satellite communication network is studied and analyzed. The delivery of Quality of Service (QoS) is an important objective. Tra¢ c allocation control is performed in the LEO satellite constellation to provide a near optimal utilization of these ISLs. An alternative solution is proposed in this research, in which a combination of two algorithms will be used to allocate tra¢ c in this dynamic satellite network. The …rst algorithm allocates tra¢ c during small time intervals, based on an assumption that the topology is unchanged during these intervals. The second algorithm allocates tra¢ c after topology updating has been accomplished. Tra¢ c allocation respects some constraints including QoS (due to multiservice requirements), capacity constraints, tra¢ c distribution, and availability constraints. Both theoretical and empirical studies have been undertaken to examine the performance of the proposed algorithm, denoted GALPEDA (Genetic Algorithm Linear Programming and Extended Dijkstra Algorithm). The proposed algorithm provides privileges to a class of high priority tra¢ c, including bene…ts for tra¢ c allocation of multiclass tra¢ c in LEO satellite communication. It provides a novel tra¢ c allocation mechanism to cope with the dynamic topology of a LEO satellite; moreover this algorithm distributes multiservice tra¢ c evenly over the network. Simulations results are provided.