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Satellite and Space Communications, 2006 International Workshop on

Date 14-15 Sept. 2006

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  • [Front cover]

    Publication Year: 2006 , Page(s): C1
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  • Proceedings of the 2006 International Workshop on Satellite and Space Communications (IWSSC2006)

    Publication Year: 2006 , Page(s): nil1
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  • Copyright page

    Publication Year: 2006 , Page(s): nil2
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  • Sponsors

    Publication Year: 2006 , Page(s): nil3
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  • Message from the General Chair and the General vice-Chair

    Publication Year: 2006 , Page(s): nil4
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  • Message from the General Co-Chairs and Finance Chairs

    Publication Year: 2006 , Page(s): nil5
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  • Message from the IWSSC 2006 Technical Program Chair and co-Chair Welcome to IWSSC 2006!

    Publication Year: 2006 , Page(s): nil6
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  • Conference committees

    Publication Year: 2006 , Page(s): nil7
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  • Technical Programme Committee

    Publication Year: 2006 , Page(s): nil8
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  • Program Committee

    Publication Year: 2006 , Page(s): nil8
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  • list-reviewer

    Publication Year: 2006 , Page(s): nil9 - nil10
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  • Table of contents

    Publication Year: 2006 , Page(s): nil11 - nil16
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  • [Breaker page]

    Publication Year: 2006 , Page(s): 1
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  • Characterization of the Attenuation due to Rain Cell Fields applying Cellular Automata to Weather Radar Images

    Publication Year: 2006 , Page(s): 3 - 7
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (5176 KB) |  | HTML iconHTML  

    A straightforward linkage between rain cell dynamics in terms of reflectivity Z (dBz) or its equivalent rain rate R (mm/h) and satellite or terrestrial radiolink attenuation can be performed. This work focuses on the presentation of an approach for assessing and characterizing rain cell dynamics based exclusively on the analysis of the radar reflectivity scans recorded in weather radar image, and without an a priori assumption on the structure of rain cells. This research has been addressed by using cellular automata. Rain cell dynamics are simulated by using probabilistic cellular automata rules and tracking vectors which indicate a global advection direction and velocity View full abstract»

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  • Turbo Decoder Development in Regenerative Communications Satellites

    Publication Year: 2006 , Page(s): 8 - 12
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (6203 KB) |  | HTML iconHTML  

    For regenerative telecom satellite systems, the turbo decoder has become a basic component of the on-board processing (OBP). This paper presents the algorithm selection choices and the test bench policy during the design process of a communication system critical block such as a turbo decoder compliant with the DVB-RCS standard (digital video broadcast-return channel satellite). The architecture, based on the max-log-map algorithm, is described emphasising results and advantages of the storage requirement reduction policy applied. Secondly, the chosen test policy is presented, it has considered the specific Space environment requirements and difficulties to fulfil performance evaluations of some complex algorithms in a short period of time. This method has allowed a fast debugging and fine-tuning of the design in order to get the best area, frequency, and performance trade-off, together with having sped-up bit error rate (BER) measurements to just days when normally it would have required weeks of operation View full abstract»

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  • Frequency-Hopping Techniques for Secure Satellite TT&C: System Analysis & Trade-Offs

    Publication Year: 2006 , Page(s): 13 - 17
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4040 KB) |  | HTML iconHTML  

    Near future on-board telemetry, tracking and command (TT&C) equipment for secure communications will likely adopt frequency hopping (FH) instead of direct sequence (DS) spread spectrum (SS) techniques. As far as TT&C systems will have to cope with jammer-to-signal power ratios higher than 50 dB, classical DS approaches must be abandoned in favour of more robust FH solutions. In the following paper we present an overview of synchronization, channel coding and modulation issues for next generation anti-jamming TT&C transponder under study and design at Alcatel Alenia Space-Italy (AAS-I) View full abstract»

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  • Design and Simulation of a Proposed Radon Based OFDM Transceiver

    Publication Year: 2006 , Page(s): 18 - 22
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4879 KB) |  | HTML iconHTML  

    In this paper, a class of discrete Radon transform, namely, finite Radon transform is proposed for the first time as a new technique in the realization of the orthogonal frequency division multiplexing (OFDM). The Radon transform is chosen in the OFDM structure to serve as a data mapper instead of the conventional data mapping techniques like the phase shift keying (PSK) mapping, in a way that ensure increasing the orthogonality of the system. The Fourier domain approach is found here to be the more suitable way for obtaining the forward and the inverse of the Radon transform. It is shown that this new application increases the orthogonality significantly due to the use of the inverse Fourier transform twice, namely, in the data mapping and in the sub-carrier modulation also, due to the use of an efficient criterion in determining the mapped data, which is called the optimal ordering criterion View full abstract»

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  • [Breaker page]

    Publication Year: 2006 , Page(s): 23
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  • Depolarization Mitigation using Frequency Offset in the Dual-Polarized X-Band for EESS

    Publication Year: 2006 , Page(s): 25 - 28
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (5205 KB) |  | HTML iconHTML  

    Dual-polarization frequency reuse technique has been actively adopted in space-to-earth links for earth exploration satellite service (EESS) to meet growing demands on high rate data transmission over the restrictedly allocated bandwidth in X-band. However, the performance of the dual-polarization system is affected by depolarization due to tropospheric propagation impairments such as rain drops and ice particles. In this paper, we investigate the offset scheme as an approach to mitigate the depolarization that always exists inherently in the dual-polarized satellite system. We present numerical formulas to estimate the depolarization effects as a function of the offset frequency, using theoretically derived CPA and XPD, in dual-polarized X-band down link channels for EESS. In addition, we present an example of link budget evaluated by using the calculated parameters View full abstract»

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  • Jointly Optimal Routing and Resource Allocation in Hybrid Satellite/Terrestrial Networks

    Publication Year: 2006 , Page(s): 29 - 33
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (5138 KB) |  | HTML iconHTML  

    In the future hybrid satellite/terrestrial networks, efficient routing at network layer and allocation of resources at link layer will have to be performed in order to satisfy traffic requests and minimizing at the same time the cost of the allocated bandwidth among the heterogeneous network components. This simultaneous routing and resource allocation (SRRA) problem can be specified in the framework of network utility maximization (NUM) theory, according to which each layer of the communication network corresponds to a decomposed subproblem of a global optimization problem, and the interfaces among layers are represented as functions of the optimization variables coordinating the subproblems. These sets of variables are associated by specific restrictions. Since the solution of the SRRA problem directly requires coordination among possibly all sources, thus it is impractical in real networks, we propose a decentralized and distributed solution which is based on the Lagrange dual decomposition method and allows defining a bandwidth-related pricing strategy View full abstract»

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  • Optimal key scheduling for secure satellite broadcasting to mobile users

    Publication Year: 2006 , Page(s): 34 - 38
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (6001 KB) |  | HTML iconHTML  

    Cryptography will be the most suitable technique to protect the access to subscribed added-value services for mobile applications provided through satellite broadcasting (e.g., localization and mobile TV). Although satellite broadcasting allows provision of the service even in remote locations, it may also prevent small mobile devices from sending feedback to the satellite when no special return link is provided. In specific locations, where the satellite signals cannot be received due to shadowing or interference, mobile users may also lose the key management data transmitted by the satellite, thus being impossible for them to decrypt the broadcasted data related to the service. A way to overcome these issues is the re-transmission of keys in order to guarantee that the largest set of legitimate receivers has the updated (set of) keys. In this paper we analyze the problem of key update in a mobile user context and propose a scheduling algorithm for key broadcasting that minimizes the number of mobile users that are prevented from updating their crypto keys. Our results are supported by simulations View full abstract»

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  • [Breaker page]

    Publication Year: 2006 , Page(s): 39
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  • TCP Hybla Performance in GEO Satellite Networks: Simulations and Testbed

    Publication Year: 2006 , Page(s): 41 - 45
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (5819 KB) |  | HTML iconHTML  

    TCP connections that incorporate satellite links are greatly disadvantaged with respect to entirely wired connections, because of their longer round trip times (RTTs). TCP Hybla has been conceived with the primary aim to solve this problem, therefore it appears quite promising in geostationary (GEO) satellite environments, where the long propagation time greatly affects the RTT. In order to compare TCP Hybla with TCP NewReno, SACK and Westwood in the satellite environment, we have reproduced suitable scenarios based on a GEO bent-pipe satellite by means of both the ns2 simulator and a Linux-based testbed developed at University of Bologna. The obtained results show that TCP Hybla allows a better efficiency in utilizing the available satellite bandwidth, especially for high packet error rates and/or high satellite bandwidth values. This work has been carried out within the European-funded network of excellence SatNEx II (contract No. IST-027393) View full abstract»

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  • Use of Quickstart for Improving the Performance of TFRC-SP Over Satellite Networks

    Publication Year: 2006 , Page(s): 46 - 50
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (5911 KB) |  | HTML iconHTML  

    The TCP-friendly rate control for small packets (TFRC-SP) protocol was designed for applications including streaming audio and voice over IP which send small packets. The long round trip delay of a satellite link could degrade the performance of such applications including streaming audio and VoIP that use TFRC-SP. In this paper, we analyze the performance of TFRC-SP carrying live streaming audio and VoIP over networks that include satellite paths. We also propose using the quickstart algorithm along with TFRC-SP to improve the performance of these applications over a satellite link View full abstract»

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  • [Breaker page]

    Publication Year: 2006 , Page(s): 51
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