Satellite Communication Services Research Articles

Network Coding Design for Reliable Satellite Communication Services

In this paper, we present a possible way forward to the design of network coding (NC) as a virtual network functionality offered to the communication service designer. Specifically, we propose the integration of NC and Network Function Virtualization (NFV) architectural designs. The integration is

A compact planar antenna with extended patch and truncated ground plane for ultra wide band application

AbstractIn this article, a compact broadband planar monopole microstrip patch antenna with extended patch and a truncated ground plane is proposed for ultra‐wideband application. The optimal dimensions of the proposed antenna are 20 × 20 × 1.6 mm3. The proposed antenna is fabricated on FR4 substrate that is a low‐cost commercially available substrate with εr = 4.3 and a loss tangent of 0.025. The impedance bandwidth (defined by the magnitude of S11 less than −10 dB) of the proposed antenna is 127% (3.13‐14.07 GHz). The peak gain and radiation efficiency of the proposed antenna are 3.4 dB and 78%, respectively. The proposed antenna exhibits a stable radiation pattern at the operating band. The simulated results of the proposed antenna are observed to be in agreement with the measured results when fabricated. The proposed antenna supports various frequency bands such as ultra‐wideband, 3.5/5.5 GHz WiMAX bands, 5.2/5.8 GHz WLAN bands, X Band (8‐12 GHz), satellite communication, and other wireless communication services. The proposed design and its various results have been discussed in further detail.

High-precision Ocean navigation with single set of BeiDou short-message device

The high-precision navigation and positioning with GNSS has become widely used in various applications with the development of new GNSS systems, such as BeiDou and Galileo. For marine applications, high-precision navigation and positioning with GNSS is still a challenge since the requirement of the communication link is a problem on sea. Both DGNSS and RTK require data communication between base station on land and the rover station on sea. The data communication can be performed by providers of the marine satellite communication service, such as Intelsat, Eutelsat, Telesat and the SpaceX. However, the cost is too high to be afforded by ordinary GNSS users. The BeiDou short-message service provides an efficient way for the data communication between reference station on land and rover station on sea. Each BeiDou message length is limited to 78 bytes, and the communication frequency is limited to 60 s. Based on the BeiDou short-message service, the high-precision positioning has been achieved in previous studies. However, multiple set of short-message devices are used and the cost is still high. In this research, based on dual-frequency GNSS data, we propose the high-precision navigation on sea with single set of short-message device. The space-relative and time-relative positioning methods are integrated to reduce the data requirements. That is, first, every minute precise position is acquired with traditional space-relative positioning method and then the position of the other epochs is derived with time-relative positioning method. The experimental results based on buoy observations on sea show that the navigation accuracy can reach up to cm level in both horizontal and vertical directions. The proposed method can meet the requirements of different marine applications such as tide monitoring and wave monitoring.

ANALISIS PIUTANG TERHADAP LIKUIDITAS PERUSAHAAN (Studi Kasus pada PT. Telekomunikasi Indonesia Tbk. dan PT. Indosat Tbk.)

As according to section 3 association of company, PT csope. Single Telecommunications of especial Tbk Activity and especial activity scope of company is to carry out domestic telecommunications sevice, which cover telephone, telex, telegram, satellite, customer circuit, electronic letter and peripatetic communications service and cellular, In order to quickening telecominications medium development and make Company as operator have internastional level to, and also improve technology, membership and knowledge all its employees, in the year 1995. Company have work is equal to all partner in development, and management pengoprasian of telecommunications medium in five from seven regional division through is same job pattern of Operation (“KSO”)As according to section 3 Assocition of Company, especial activity and scope activity of PT. Indosat Tbk cover to make a move in the field of multimedia and telecommunications in Indonesia give amenity to all its customer for the case of question in around telecommunications (seluler, SLI, etc), denunciating, guidance subscribe to, purchasing of maiden card of GSM prabayar/ CDMA/ internet prabayar card/ refill voucer, and/ or payment of invoice, direct etc in place. PT. Telecomunications Indonesia Tbk and PT. Indosat Tbk conduct sale creditly as a mean to improve sale volume, because at the higtht of sale volume hence directly can improve provite. Credit sales will result the happening of receivable, the duration receivable turn into cash in company can be measured with receivable turn overratio and period gathering of receivable. Receivable turn over And period gathering of tardy receivable can influence company likuiditas storey; accepted Excelsior credit sales, hence progressively lower company likuiditas storey; level conversely progressively lower accepted credit sales, hence excelsior mount company likuiditasTo measure or analyse credit sales storey; level used by formula which consist of : receivable turn over ratio, and period ratio gathering of receivable. While to mesure company likuiditass storey; level used by likuiditas ratio, that is : ratio current/ fluent ratio, ratio quick/ ratio quicly, and ratio cash/ cash ratio. Storey level Sale of PT. High Telecomuniations Indonesia Tbk enough with good company likuiditas level of fluent ratio, ratio quickly and cash ratio under 100% indicating that company find difficulties finance in fulfilling obligation short-range or fluent debt on time. While at PT. Indosat Tbk, mount from high sale enough, with level mount good company likuiditas of fluent ratio, ratio quickliy and cash ratio below/ under 100 % indicating that company find difficulties finance in fulfilling obligation short-range or fluent debt on time.Keywords: accounts receivable, the company's liquidity.

Satellite Air Interface Evolutions in the 5G and IoT Era

An overview of satellite air interface evolution, in light of new initiatives to consider satellite networks as an integrated part of the 5th generation of communication networks, is presented. The study of non-terrestrial networks has identified a variety of satellite communication services. Despite that, the adoption of air interface solutions over satellite links faces several challenges that require in-depth analyses and possible iterations in design trade-offs. This has created new incentives for several on-going or planned R&D projects in support of new standardization. While some preliminary observations can be made based on recent studies, further analyses are required to reach a consolidated view.

A Novel Model for Predicting Sun Outage in Satellite Communication

A sun outage is an interruption or distortion of satellite communication signals caused by interference from solar radiation. There is a serious interference to satellite communication services in a special period of time. In the present paper, a novel model for predicting sun outage that is effective and can greatly improve accuracy and precision of sun outage prediction of earth station in satellite communication is presented.

Management of an outsourced satellite phone development project: Sasken's experience

Although Indian IT industry is well known for its software services business capabilities, product development still eludes the sector. This case illustrates the 5-year journey of Sasken Technologies – a mid-sized communication services company located in India to design, pre-build, test, integrate and certify a complex end-to-end satellite phone for a global satellite communication service provider. Knowing very well the inherent risks and uncertainties associated with such technology-intensive project, the CEO of Sasken signed the contract with the client with immense belief in his team to execute the project successfully. The case highlights the challenges encountered by the project managers of Sasken in acquiring the technology know-how, integrating hardware and software components, managing globally distributed teams, meeting regulatory requirements and mitigating unforeseen risks inherent in such off-shore outsourcing projects.

A large ring deployable mechanism for space satellite antenna

With the development of space technology, new demands for satellite communications services, space and earth observations drive the requirement for large aperture space antennas. In order to meet the missions, this paper presents a kind of novel single mobility deployable ring mechanism based on a set of planar six-bar linkages. The ring mechanism has very high deploy/fold ratio, which is suitable for building large scale satellite deployable antenna. The mobile assembly of the ring structure and synchronous movement compatibility conditions are investigated, then the synchronization movement of the six-bar linkage modules can be realized by using close-loop cable and dual slider-crank mechanisms, which ensure the single mobility of the whole ring mechanism. Two types of driving mode for the deployable ring mechanism including cable driven and torsion spring driven are studied, and the high rigidity driving joints are designed. Finally, a ground experimental prototype of a 3.9 meter in diameter is fabricated to show the feasibility of the proposed mechanism, the deployment accuracy are also tested and the results show the good repeatability for the ring deployable mechanism.

Industry Participation in India’s Space Program: Current Trends and Perspectives for the Future

ABSTRACTOver the past five decades, India has progressed to create one of the largest national space programs in the world, delivering space-based technology to solve the problems of man and society. The present work provides an overview of current trends regarding industry participation in the national space program of India. While insight into industry participation and upstream activity is provided in the space transportation and development of satellite systems, commercial aspects of satellite communication services, use of geospatial data, and navigation and timing services are addressed as a part of the downstream applications. Specific recommendations to expand the footprint of the participation of Indian industry in the utilization of space technology nationally with possible expansion internationally are provided herein for space program managers and policymakers for both the upstream and downstream activities.

Printed ultra-wideband monopole U-slotted antenna for triple band-rejection

A low-profile microstrip-fed planar monopole ultra-wideband (UWB) antenna with triple band rejection characteristics is proposed. The proposed antenna configuration consists of a bevelled ground with multiple U-slots embedded on the radiation patch for realizing the band notch characteristics. The notched frequency bands can be controlled by adjusting the parameters of the slots. The measured results demonstrate that the fabricated antenna exhibits an impedance bandwidth from 3 to 11 GHz for a VSWR ˂ 2 with three rejection bands at 3.38‒3.73 GHz for WiMAX, 5.12‒5.84 GHz for WLAN and 7.23‒8.56 GHz for X-band satellite communication services. Band rejection function is confirmed by the three gain diminishes occurring at 3.7, 5.35, and 8 GHz and stable gain outside the rejection bands. Measured group delay ensures that the designed antenna has good transmission capability of UWB signal with minimum distortion.

APPLICATION OF VISION METROLOGY TO IN-ORBIT MEASUREMENT OF LARGE REFLECTOR ONBOARD COMMUNICATION SATELLITE FOR NEXT GENERATION MOBILE SATELLITE COMMUNICATION

Abstract. Satellite for next generation mobile satellite communication service with small personal terminal requires onboard antenna with very large aperture reflector larger than twenty meters diameter because small personal terminal with lower power consumption in ground base requires the large onboard reflector with high antenna gain. But, large deployable antenna will deform in orbit because the antenna is not a solid dish but the flexible structure with fine cable and mesh supported by truss. Deformation of reflector shape deteriorate the antenna performance and quality and stability of communication service. However, in case of digital beam forming antenna with phased array can modify the antenna beam performance due to adjustment of excitation amplitude and excitation phase. If we can measure the reflector shape precisely in orbit, beam pattern and antenna performance can be compensated with the updated excitation amplitude and excitation phase parameters optimized for the reflector shape measured every moment. Softbank Corporation and National Institute of Information and Communications Technology has started the project "R&D on dynamic beam control technique for next generation mobile communication satellite" as a contracted research project sponsored by Ministry of Internal Affairs and Communication of Japan. In this topic, one of the problem in vision metrology application is a strong constraints on geometry for camera arrangement on satellite bus with very limited space. On satellite in orbit, we cannot take many images from many different directions as ordinary vision metrology measurement and the available area for camera positioning is quite limited. Feasibility of vision metrology application and general methodology to apply to future mobile satellite communication satellite is to be found. Our approach is as follows: 1) Development of prototyping simulator to evaluate the expected precision for network design in zero order and first order 2) Trial measurement for large structure with similar dimension with large deployable reflector to confirm the validity of the network design and instrumentation. In this report, the overview of this R&D project and the results of feasibility study of network design based on simulations on vision metrology and beam pattern compensation of antenna with very large reflector in orbit is discussed. The feasibility of assumed network design for vision metrology and satisfaction of accuracy requirements are discussed. The feasibility of beam pattern compensation by using accurately measured reflector shape is confirmed with antenna pattern simulation for deformed parabola reflector. If reflector surface of communication satellite can be measured routinely in orbit, the antenna pattern can be compensated and maintain the high performance every moment.

A new satellite communication bandwidth allocation combined services model and network performance optimization

With the rapid development of online to offline economy, new services compositions would take up a great part in the satellite communication. More and more new services compositions request more bandwidth and network resources, which lead to serious traffic congestion and low channel utilization. Suffering from isolated link connection and changeable delay under the satellite environment, current bandwidth allocation schemes could not satisfy with the demand of low delay and high assess rate for new satellite services. This paper focuses on bandwidth allocation method for satellite communication services compositions. The novel models of services compositions with single-hop Poisson distribution are designed to simulate original traffic arrival. Isolated independent coefficients take an original distribution to adapt to isolated disconnections. Services queue waiting time would be judged by acceptable delay threshold. Models provide new services compositions with more precise arrival distributions. In order to improve traffic congestion, the method combined services models, and a network performance is proposed. Optimal reserved bandwidth is set according to the priority and arrival distribution of different services compositions, which classify services with feedback transmission performance. We design minimum fuzzy delay tolerant intervals to calculate delay tolerant threshold, which adapt random delay changes in the services network with delay tolerant features. The simulation in OPNET demonstrates that the proposed method has a better performance of queuing delay by 16.3%, end-to-end delay by 18.7%, and bandwidth utilization by 13.2%. Copyright © 2016 John Wiley & Sons, Ltd.

A miniaturized triple band‐notched MIMO antenna for UWB application

ABSTRACTIn this article, a miniaturized multiple‐output (MIMO) antenna with Triple Band‐Notched Characteristics for ultra‐wideband (UWB) application is proposed. With two half‐planar‐monopoles as radiators to achieve miniaturization, the overall size of this antenna is only 28 × 22 mm2 (0.46 λg×0.36 λg) = 616 mm2 (0.16 ), where λg is the guided wavelength at the lowest operation frequency. By introducing a T‐shaped stub on the ground plane, not only is the isolation between radiators greatly enhanced, the impedance (−10 dB S11) performance is also improved significantly. Two C‐shaped slots are etched into each radiator to obtain three notched bands (3.4–3.9 GHz, 5.05–5.85 GHz, 7.9–8.4 GHz) for blocking WiMAX, WLAN, and X‐band satellite communication services. The simulated results are studied and the measured results show that the impedance bandwidths of the proposed antenna covers all UWB band from 3.1 to 10.6 GHz except the notched bands, while a low mutual coupling of less than −18 dB is achieved at the entire band. Furthermore, the measured radiation performances and envelope correlation coefficient also demonstrate the proposed antenna could be a good candidate for UWB system. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:642–647, 2016

위성망 이중화를 위한 국내 강우율 공간분포 분석

Abstract This paper proposes appropriate locations for site diversity to provide stable satellite communication service in Korea. For this pur-pose, we analyzed rainfall rate data measured by KMA for 5 years at 88 sites, and the variations of simultaneous occurrence of rainfall rate in pairs of sites using the correlation coefficient. This paper provided contour maps of the spatial ditstribution of rainfall rate corre-lation, and proposed information on the optimum sites/regions for the operation of muti-uplink satellite systems, in 4 cities which were principal in field of satellite communication in Korea.Key words: Site Diversity, Satellite Communication, Rainfall Rate, Correlation Coefficient, Correlation Map  Q“)”0•(Technical Regulation Division, National Radio Research Agency) xManuscript received September 8, 2015 ; Revised October 19, 2015 ; Accepted November 9, 2015. (ID No. 20150908-066)xCorresponding Author: Yong-Ki Kwon (e-mail: ygkwon@msip.go.kr) ⓒ Copyright The Korean Institute of Electromagnetic Engineering and Science. All Rights Reserved.

위성통신용 삼중대역 동시사용 안테나 설계

As satellite communications services are showing gradual growth, so are the needs for dual or tri-band antennas greater than performance of conventional single-band antennas. In this paper, a simultaneously operable tri-band antenna for SATCOM(Satellite Communications) is proposed. It is different from conventional methods of implementing tri-band through replaceable horns, while it is designed with a tri-band feed assembly composed of corrugated and dielectric horns and reflectors of gregorian type to transmit and receive tri-band of X, Ku and Ka band simultaneously. And simulated and measured values were compared and analyzed for characteristics of the proposed antenna. In the results, radiation patterns of the proposed tri-band antenna were close to the simulated ones and also met specifications.

A compact broadband printed monopole antenna with U-shaped slit and rectangular parasitic patches for multiple applications

This paper presents a compact broadband printed monopole antenna with U-shaped slit in the partial ground plane and rectangular parasitic patches adjacent to the microstrip line for multiple applications. The optimal dimensions of the proposed antenna are 35 × 25 × 1.5 mm3 and is fabricated on commercially available low-cost FR4 substrate with εr = 4.3 and 0.025 loss tangent. Due to introduction of rectangular parasitic patches and U-shaped slit large bandwidth has been achieved. The impedance bandwidth (return loss, magnitude of S11 < 10 dB) of the proposed antenna is 139% (2.9–16.3 GHz). The proposed antenna covers ultra wide band applications, 5.2/5.8 GHz WLAN bands, 3.5/5.5 GHz WiMAX bands, X band (8–12 GHz), satellite communication, and other wireless communication services. The study shows that there is good agreement in simulated and measured results. Nearly stable radiation patterns have been obtained throughout the operating band. Antenna results and details are discussed and elaborated.

Advanced Antenna Technologies for Satellite Communications Payloads

A review of various antenna technologies suitable for satellite communications and applicable to fixed satellite, broadcast satellite, mobile communications, and personal communications services is presented. Antenna technologies suitable for generating contoured beam and multiple-beam antennas are reviewed. Design considerations for reflector antennas and feed assemblies and antenna performance in terms of coverage gain, sidelobe isolation, and cross-polar isolation are discussed. Current and future technological trends are presented in the above areas.

Technology Trends and Challenges of Antennas for Satellite Communication Systems

Communication is one of the most essential activities of mankind and there is no doubt that satellite communications have made a tremendous stride in this matter. The goal has been to create uninterrupted, seamless, high throughput connectivity no matter where. The fact that this is all possible is because of the existence of electromagnetic waves: Antennas play a pivotal role in advanced functionality, efficient usage of the bandwidth, and cost effective deployment of this technology. The trends of the technological development of antennas for a wide range of commercial satellite communication services and the challenges faced in their development are chronologically reviewed. Various antenna concepts are summarized and future challenges are projected. A rather comprehensive list of references is included to assist the reader with further reading beyond this paper.

Ka 대역 다중모드 모노펄스 추적 시스템을 위한 한 쌍의 슬롯(Slot)을 갖는 모드커플러 설계

OTM(On-The-Move) 위성통신 시스템은 차량에 탑재되어 고속 주행하거나 요동이 심한 지역을 주행하면서 위성 통신 링크를 안정적으로 유지하여야 한다. 따라서 열악한 환경에서도 정밀 추적이 가능하고, 차량에 탑재할 수 있도록 소형/경량화된 위성 추적 시스템이 필요하다. 2개의 슬롯(slot)으로 구성된 단일 모드 커플러를 사용하여, 원형 편파 특성을 이용하여 하나의 물리적 채널로 상하, 좌우 2개의 차신호를 동시에 비콘 수신기까지 전달하는 방안을 제안하고, 측정된 추적 오차신호를 제시한다. The main mission of OTM(On-The-Move) satellite communication system is to provide satellite communication service while moving on a vehicle. So it should have a capability to maintain a reliable communication channel when it travels at high speeds or in a severe fluctuation region. This paper presents a small-sized multi-mode monopulse structure applicable to OTM satellite communication system which has only single mode-coupler with a pair of slot using a feature of circular polarized received signal. And tracking error signal is defined using fundamental and high-order modes.

Corner truncated broadband patch antenna with circular slots

ABSTRACTIn this communication, a corner truncated broadband patch antenna with circular slots is presented. The proposed antenna is fabricated on 14 * 14 * 1.57 mm3 Rogers RT5870 substrate (εr = 2.33 and loss tangent of 0.0012) and a 50‐Ω SMA connector is used for excitation. Bandwidth enhancement has been reported due to cutting of two circular slots and truncating the corners of the square patch, which gives rise to mode splitting phenomenon and better impedance matching. Simulated results show that the impedance bandwidth (S11 < 10 dB) of the proposed antenna is 19% (10.8–13.2 GHz). Measured results are in good agreement with the simulated results. The fractional bandwidth of the proposed antenna has enhanced from 8.5 to 19% as compared to the simple patch antenna, showing an enhancement of 123%. The peak gain of the proposed antenna is 7 dB. The antenna finds application in satellite communication, radar communication, and other alleged wireless communication services. Details and comparison of the proposed antenna with simple patch antenna have been described. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:845–849, 2015