Mobile Satellite Communication Systems Research Articles

Secure anonymous authentication scheme without verification table for mobile satellite communication systems

SUMMARYAn authentication scheme is one of the most basic and important security mechanisms for satellite communication systems because it prevents illegal access by an adversary. Lee et al. recently proposed an efficient authentication scheme for mobile satellite communication systems. However, we observed that this authentication scheme is vulnerable to a denial of service (DoS) attack and does not offer perfect forward secrecy. Therefore, we propose a novel secure authentication scheme without verification table for mobile satellite communication systems. The proposed scheme can simultaneously withstand DoS attacks and support user anonymity and user unlinkability. In addition, the proposed scheme is based on the elliptic curve cryptosystem, has low client‐side and server‐side computation costs, and achieves perfect forward secrecy. Copyright © 2013 John Wiley & Sons, Ltd.

LTE-satellite: Chinese proposal for satellite component of IMT-Advanced system

As a complementary to terrestrial mobile communication systems, mobile satellite communication system can fill the gaps that cannot be covered by terrestrial network, and provides an irreplaceable solution for emergency communication in disaster. To pave the road for future satellite/terrestrial integrated communication networks, ITU-R invited proposals for candidate Radio Interface Technology (RIT) for the satellite component of International Mobile Telecommunications (IMT)-Advanced. China proposed the RIT of Long Term Evolution (LTE)-satellite as a candidate to be considered as IMT-Advanced satellite technology. The submitted LTE-satellite candidate RIT is specified based on terrestrial LTE-Advanced FDD standards that are developed in 3GPP. Considering satellite requirements, a number of modifications to LTE-Advanced are made to adapt to satellite radio transmission environments. This paper provides a general introduction of the new characteristics of LTE-satellite.

CQI Prediction for Shadow Fading in LTE-Compatible GEO Mobile Satellite Communications System

CQI(Channel Quality Indicator) is an essential indicator for AMC(Adaptive Modulation and Coding) technique in LTE. Due to the long delay of GEO satellite channel, CQI prediction is necessary to ensure effective AMC in LTE-compatible GEO mobile satellite communications system. The complete procedure and problem encountered when doing AMC in satellite system are introduced and the difficulties of prediction are analyzed. In order to obtain meaningful and feasible CQI prediction results, a complete prediction scheme is proposed. By using approximate CQI data which is smoothed and with only shadow fading influence, various prediction models are compared. Taking both computation complexity and prediction performance into account, two models, ARIMA (Autoregressive Integrated Moving Average) and Kalman filter are chosen to be applied in this scheme. Simulation results show that the prediction performance is very well with the proposed method, which can surely guarantee AMC performance.

육상 이동 위성 시스템의 통신 성능 향상을 위한 MIMO 원형 편파 급전 네트워크

본 논문은 육상 이동 위성(Land Mobile Satellite: LMS) 시스템의 통신 성능 향상을 위해 기존의 <TEX>$2{\times}2$</TEX> MIMO 채널에서 <TEX>$4{\times}4$</TEX> 채널로 확장할 수 있는 MIMO 원형 편파 급전 네트워크를 제안한다. 기존의 추가적인 통신 채널 확보를 위해서는 위성국에서 안테나 설치 공간상의 제약이 있기 때문에 이격 거리가 충분한 추가 위성국을 필요로 한다. 이로 인한 비용 및 MIMO 통신 채널의 한계 문제를 극복하기 위하여, 동일한 원형 편파 간에 이격 거리가 없이도 높은 격리성을 확보할 수 있는 MIMO 원형 편파 급전 네트워크를 제안하였다. 제안하는 급전 네트워크의 포트간 격리성과 각 포트의 매칭 상태를 수식적으로 증명하였고, <TEX>$4{\times}4$</TEX> MIMO 채널의 통신 성능 향상을 채널 모델 측면에서 제시 및 확인하였다. MIMO 원형 편파 급전 네트워크를 원형 편파 패치 안테나 구조로 실제 제작하고 측정하여 7~10 dB의 다이버시티 이득을 얻었고, 약 1.8배로 채널 용량이 향상되었음을 확인하였다. In this paper, we propose the MIMO circular polarization feed network to enhance the communication performances from the previous <TEX>$2{\times}2$</TEX> MIMO channel to <TEX>$4{\times}4$</TEX> channel for Land Mobile Satellite communication system. The only possibility to extend the communication channel is to use the additional satellite because of the limitation of satellite spaces to install additional antennas. For overcoming this problems, we propose the MIMO circular polarization feed network to secure the isolation characteristics without the distant antenna space. The port isolation characteristics and each port impedance matching conditions are numerically verified and we suggest the <TEX>$4{\times}4$</TEX> MIMO channel model of the proposed system and the performances are verified. The fabricated circular polarization patch antennas with the proposed feed network are measured in the reverberation chamber and 7~10 dB of diversity gain and 80 % increasement of channel capacity are obtained.

MUSIC 알고리즘 기반 블라인드 빔포밍 등화 시스템

블라인드 등화기법은 트레이닝 시퀀스 없이 수신된 신호만을 가지고 채널 등화를 할 수 있다. 블라인드 등화시스템은 트레이닝 시퀀스가 존재하지 않기 때문에 블라인드 등화 시스템을 통해서 대역 효율을 향상시킬 수 있는 장점이 있습니다. 이 때문에 이동 위성 통신에서 유저들의 이동으로 인해서 발생하는 ISI를 제거하기 위해서 블라인드 등화시스템을 사용해야 합니다. 트레이닝 시퀀스를 사용하지 않기 때문에 우리는 블라인드 등화기시스템을 통해 대역 효율을 증가시킬 수 있으며, 트레이닝 시퀀스를 사용하지 않는 이동 통신의 수신기에서는 블라인드 등화를 사용해야 합니다. 블라인드 등화는 이동 위성 통신 채널에 적합합니다. 이 블라인드 등화를 이동 위성 통신 시스템에 적용시켜 BER 성능을 향상시키는 것은 매우 중요합니다. 본 논문에서는 MCMA와 SAG MCMA를 적용한 블라인드 등화 시스템을 제안한다. 이 시스템은 빔포밍과 MUSIC 알고리즘 그리고 coordinate change 기법을 적용해서 BER 성능이 향상됨을 시뮬레이션을 통해서 확인할 수 있다. Blind equalization is a technique that equalizes the received signals without the training sequence. Because of the absence of training sequence, we can increase the bandwidth efficiency due to the blind equalization system. And we must use the blind equalization for removing the ISI in mobile satellite communication receiver. ISI occurs due to mobility of users in mobile satellite communications. Blind equalization is suitable for the mobile satellite communication channels. In this blind equalization, it's very important to improve BER performance to apply the mobile satellite communication system. In this paper, we propose the blind beamforming equalization system using the beamforming, MUSIC algorithm and coordinate change method. We were confirmed by the simulation that the proposed system improves the BER performance.

Ka-band를 활용한 정지궤도 위성의 도심지 전파특성 분석

In satellite communication system, propagation characteristics analysis of the receiving environment is very important, because radio quality is changed by the receiving environment. Unlike Terrestrial wireless communications, satellite communication is affected by altitude and atmospheric environment. Therefore, there are many factors to consider for propagation characteristics analysis. In this paper, signal reception environment of geostationary earth orbit was analyzed on urban environment. In order to analyze the propagation simulation, virtual buildings was established and reception environment was changed. The results of this paper would help to design the satellite mobile communication systems in Ka-band.

Design and Improving Techniques for Uplink Reference Signal in LTE Compatible Mobile Satellite Communication System

Reference Signal (RS) is used for channel estimation and sounding in LTE uplink of terrestrial system to accomplish data demodulation. However, the situation in multiple-beam mobile satellite communication system is different. The Uplink Reference Signal (UL-RS) designed in terrestrial LTE doesn’t fit the satellite environment and may result to system performance degradation. In this paper, the UL-RS pattern used in GEO multiple-beam mobile satellite communication system is proposed, as well as two enhancement techniques, i.e., full bandwidth sounding, retransmit and combined receive. System performance index calculation and simulation results prove the effectiveness of the proposed design.

An authentication and key agreement protocol for satellite communications

SUMMARYIn 2009 and 2011, Chen et al. and Lasc et al. proposed two separate authentication schemes for mobile satellite communication systems. Unfortunately, their schemes are unable to protect security in the event of smart card loss. In this paper, we propose a novel version that resists common malicious attacks and improves both the schemes of Chen et al. and Lasc et al. The security of our scheme is based on the discrete logarithm problem and one‐way hash function. A nonce mechanism is also applied to prevent replay attack. Furthermore, our scheme is more efficient than related schemes and thus more suitable for being implemented in satellite communication systems. Copyright © 2012 John Wiley &amp; Sons, Ltd.

Modeling and nonlinear computed torque control of ship-mounted mobile satellite communication system

A mobile satellite communication system (MSCS) is a device installed on a moving carrier for mobile satellite communication. It can eliminate disturbance and maintain continuous satellite communication when the carrier is moving. Because of many advantages of mobile satellite communication, the MSCSs are becoming more and more popular in modern mobile communication. In this paper, a typical ship-mounted MSCS is studied. The dynamic model of the system is derived using the generalized Lagrange method both in the joint space and in the workspace. Based on the dynamic model, a nonlinear computed torque controller with trajectory planning is designed to track an aimed satellite with a satisfied transient response. Simulation results in two different situations are presented to show the tracking performance of the controller.

Adaptive robust control of mobile satellite communication system with disturbance and model uncertainties

Adaptive robust control of mobile satellite communication system with disturbance and model uncertainties

Adaptive modulation and coding for Long Term Evolution‐based mobile satellite communication system

SUMMARYThe adaptive modulation and coding (AMC) scheme is mandatory for modern wireless communication systems to overcome inevitable channel impairments. Many of the limitations using AMC are due to the long round‐trip delay of a satellite system. This paper proposes an efficient AMC scheme with power control and symbol interleaving that can be effectively applied to satellite systems. In particular, we focus on mobile satellite systems that have maximum compatibility in a Long Term Evolution system. Simulations reveal that the proposed scheme can provide a maximum 10.2% increase of average beam spectral efficiency and a maximum of 8‐dB power gain compared with a conventional AMC scheme. Copyright © 2012 John Wiley &amp; Sons, Ltd.

Research of Flexible Repeater Technique in Satellite Communications

This paper introduces the background and basic theory of flexible repeater technology, then analyses the basic working process and principle of flexible repeater on Wideband Gapfiller Satellite (WGS), and summarizes the key technologies during implementation. Meantime, for solving the large capacity and multi-beam connection problems in mobile satellite communication system, the flexible repeater provides the necessary basis theoretical and technical support. Finally, by comparing the tradition repeaters with flexible repeater, this paper points out the flexible repeater possesses the virtue of high power efficiency and high flexibility, and could realize flexible switching of the satellite signals and resources.

Dual Hop MIMO OSTBC for LMS Communication

For a multiple antenna land mobile satellite (LMS) communication system with a terrestrial relay node, the system performance when channel state information (CSI) is not available at the source and the relay is analyzed. The system employs orthogonal space time block code (OSTBC) encoding with fixed gain amplify and forward (AF) relaying. The moment generating function (MGF) and first and second moments of the signal-to-noise ratio (SNR) at the destination are derived in exact closed form. The average symbol error rate (SER) and the amount of fading (AoF) of the system are also derived.

Wideband Modeling of Land-Mobile-Satellite Channel in Built-Up Environment

This paper presents a propagation model for land-mobile-satellite (LMS) wideband radio channel in built-up environment. The model characterizes the behavior of the radio channel, under shadowing and multipath effects due to buildings, with variation of the elevation angle of the satellite. The wideband parameters (coherent bandwidth and time delay spreading) for LMS channel, in residential and urban environments, are computed. These parameters can be considered as a measure of the amount of ISI (inter-symbol interference) of the radio channel, which distorts the received signal and accordingly increases the bit error rate. The calculated values for these parameters using our model, show very good agreement with the corresponding measured ones, which accordingly shows the validity of the developed model for radio channel design in satellite mobile communication systems.

A simple and efficient authentication scheme for mobile satellite communication systems

SUMMARYIn this article, the authors shall propose a simple and efficient authentication scheme for mobile satellite communication systems. The proposed scheme can achieve the following security requirements: (S1) withstand impersonation attacks; (S2) withstand denial server attacks; (S3) withstand smart card loss attacks; (S4) withstand replay attacks; and (S5) withstand stolen‐verifier attacks, and achieve the following functionality requirements: (F1) freely choose identity; (F2) provide mutual authentication; (F3) provide session key agreement; (F4) provide user anonymity; and (F5) provide perfect forward secrecy. In additional, the proposed scheme does not use the high complex computation, such as public key cryptosystem or secret key cryptosystem, for the mobile users' side. The proposed scheme is only based on hash functions and exclusive‐OR operations. Compared with other schemes, the proposed scheme has a lower computation cost. It is more simple and efficient scheme. Copyright © 2011 John Wiley &amp; Sons, Ltd.

Design of Stabilized Platform Controller for Mobile Satellite Communication System

The stabilized platform servo system ensures the carrier communicating with satellites stably while in motion. The key to this system is to isolate disturbance coursed by the moving of the carrier and maintain the stability of antenna directivity. This paper has compared PID algorithm and I-PD algorithm, and designed a control scheme for the stabilized platform using the combination of speed-change integral I-PD algorithm and feed-forward control. The results of the simulation and actual testing indicate that the design this paper presents has a strong suppression to disturbance and meets the precision requirements of the mobile satellite communication system.

An efficient and secure anonymous authentication scheme for mobile satellite communication systems

This paper proposes a new efficient and secure anonymous authentication scheme for mobile satellite communication systems. Compared with the related schemes, the proposed scheme achieves the following three main advantages: (1) It is just based on a secure one-way hash function for avoiding complex computations for both mobile users and network control center (NCC), (2) it does not require sensitive verification table which may cause NCC to become an attractive target for numerous attacks (e.g., insertion attacks and stolen-verifier attacks), and (3) it provides higher security level (e.g., secure mutual authentication and key establishment, confidential communication, user's privacy, simple key management, and session key independence). As a result, the proposed scheme is very suitable for lightweight-device environments because of very low computation overload on the part of both mobile user and NCC.

Digitally-Controlled Polarization-Forming Transmitting Antenna for Mobile Satellite Communication Systems

This paper presents a novel electrical polarization forming antenna for mobile satellite communication systems using linear polarization. To electrically form the desired polarization, it is necessary to excite the two orthogonal polarization antenna planes with appropriate weights. The proposed antenna uses digitally-based polarization and calibration functions to characterize the two RF paths. The calibration techniques used are critical to accurately forming the desired polarization. Proposed calibration techniques are very simple; the feedback signal consists of just amplitude levels. The proposals are validated by polarization forming measurements conducted on a fabricated antenna.

Performance Analysis of Land Mobile Satellite Communication Systems with Equal-Gain Combining over Shadowed-Rice Fading Channels

An accurate model for performance analysis of land mobile satellite (LMS) channels is the Shadowed-Rice (SR) fading model. Recently, an approximate SR model has been proposed by the author for LMS channels. Compared with the existing models, the proposed model is analytically tractable and makes it possible to approximate very accurately the probability density function (PDF) of the SR random variable (RV) by a finite weighted sum of Rice PDFs. In this paper and based on the proposed model, the statistics of the sum of independent SR RVs is studied. While this problem is well understood for common fading models such as the Rayleigh, Rice, and Nakagami, a minor attention has been devoted to the SR case. In this paper and by using the well-known Beaulieu series approach, the PDF and the Cumulative distribution function (CDF) of the sum of independent SR RVs are derived in the form of infinite convergent series. In this regard, analytical, closed-form expressions are derived for the coefficients of the Beaulieu series. To give an application of the presented results, the performance of LMS communication system employing equal-gain combining (EGC) diversity techniques over SR fading channel is investigated and novel closed-form expression is derived for the outage probability of the system.

Guest Editorial: IJSCN Special Issue on ASMS2008

This Special Issue of the Wiley International Journal of Satellite Communications and Networking hosts aselection of papers from the fourth Advanced Satellite Mobile Systems (ASMS) Conference, held inBologna, Italy, on 26–28 August 2008. The conference was organized through a joint effort of theUniversity of Bologna, the Institute of Communications and Navigation of DLR (German AerospaceCenter) and the ISI (Integral SatCom Initiative) European Technology Platform, in cooperation with theSatellite Communications Network of Excellence (SatNEx) and the sISI Specific Support Action,supported by the European Commission FP6 and FP7 programmes, respectively.The ASMS conference has become a recognized event for industry and research institutions to exchangeup-to-date information about recent advances and emerging technologies in the field of mobile satellitecommunication systems. In addition, following the successful path opened by the 2006 edition, the scope ofthe conference has been widened to include broadband and broadcast satellite systems. This is veryimportant not only because the major part of the satcom market belongs to broadcasting and broadbandaccess operators but also fundamentally because the convergence of broadcast, mobile and fixed satellitecommunications is essential to offer seamless connectivity anywhere at anytime, which is recognized as thekey element for the successful deployment of future satellite systems.This Issue collects the extendedversions of eight of the best papers presented at the ASMS 2008 Conference. The papers have been selectedwith the aim of providing an insight in the developments and findings in this exciting field. The first papershows that Low Density Parity Check (LDPC) codes can tightly approach the performance of idealmaximum distance separable codes over memoryless erasure channels, under Maximum Likelihood (ML)decoding [1]. The decoding complexity of ML decoding can be kept low thanks to a class of decodingalgorithms which exploit the sparseness of the parity-check matrix to reduce the complexity of Gaussianelimination. The second paper includes a review and characterization of possible data link technologies foraeronautical communications covering a vast range of terrestrial (direct air-to-ground) and satellite-basedsolutions, with the final goal to identify suitable candidates for a future integrated aeronautical networkbased on IPv6 protocol, supporting both cockpit and cabin communications [2]. A new method to enableIPsec authentication and integrity services at the network layer is proposed in the thirdpaper [3]. Target scenarios include satellite multicast for large-scale delivery of data and video content.In these scenarios, a cross-layer architecture can mitigate the effects of physical layer impairments andlarge latency. Stemming from the three-state land mobile satellite channel model used for physical layersimulation in the course of the DVB-SH standardization process, an improved model is proposed in thefourth paper [4]. The new model includes two major modifications: a reduction in the number of states and