Implementing a mobility architecture for a Regenerative Satellite Mesh Architecture (RSM-A) system a SPACEWAY™ perspective

This paper examines the potential interference between the Mobile Satellite Service and the Fixed Service in the Ku band. At first, the mobile satellite stations operating at sea are presented and the aggregate and the single-entry interference criteria for the terrestrial fixed service stations are calculated. Then, all the parameters that influence the interference magnitude are presented and extensively analyzed. In order to evaluate the impact of each one of them in the interference calculations, different scenarios are taken into consideration and simulations are conducted in maritime and terrestrial environment. The results are thoroughly presented and analyzed. I. INTRODUCTION The increasing demand for Mobile Satellite Services the last decades has lead to the fast development of cost effective mobile VSAT terminals and their extensive use for many applications. Mobile VSAT antennae can easily be installed on almost every vehicle including cars, small vans, trucks, sea going vessels and mobile platforms like cruise ships, ferries, geo seismic ships, drilling vessels and oil production platforms. Many of these systems operate in the C band (6/4 GHz), while there is a great interest for their deployment in the Ku band (14/11/12 GHz) (uplink in 13.75-14.5 GHz and downlink in 10.7-12.75 GHz frequency bands) in geographic areas covered by these bands. These mobile satellite systems are used to provide wideband satellite services, such as streaming video, bringing Internet connectivity to remote areas and carrying sensitive voice or data traffic. The transmitting bit rates may vary between 19.2 kbps up to 1.544 Mbps (Ref 1). However, according to the International Telecommunication Union (ITU) Regulations, the 13.75-14.5 GHz and 10.7-12.75 GHz frequency bands are exclusive for the Fixed Satellite Service (FSS) in all ITU regions and allocated for use to the terrestrial Fixed Service (FS) in many countries around the world through ITU footnotes. Hence, whichever frequencies of operation for the mobile earth stations are chosen in the Ku band, there is a possibility of interference, either the earth station transmission interfering with reception at the Fixed Service stations (in the 13.75-14.5 GHz frequency band), or the Fixed Service station transmissions interfering with reception at the mobile earth stations (in the 10.7-12.75 GHz frequency band). The magnitude of interference between two systems operating in the same or adjacent frequency bands depends on many factors, such as the transmission loss along the interfering path and the permissible interference levels at the receivers. For the terrestrial Fixed Service, long- and short-term interference criteria have been established in order to facilitate the sharing with the other systems operating in the same frequency bands. The possibility and the magnitude of the interference need to be examined in detail in each case, taking all these factors that influence the interference into account. In case of a mobile earth station, significance must be given also to the time variant nature of the interference. That means that additional parameters should be taken into ) ( ) (

The two incumbent aeronautical satellite communication service providers are operating in L-band with very little scope for expansion. Thus, new service offerings are aiming at new frequency bands where capacity is still available and the expectation for lower cost per megabyte may be realisable. Ku-band has already seen both, failed Aerosatcom service provision attempts (e.g. CbB) and new start-ups (e.g. Panasonic/AeroMobile/Lufthansa). Kaband has become the new frontier, seen to provide relief from growing demand on spectrum where Ku spectrum may run into limitations, when Fixed Satellite Services (FSS), Broadcast Satellite services (BSS) and Mobile Satellite Services (MSS) start to compete for satellite capacity and orbital slots in earnest. An ESA-funded study aims at the assessment of the commercial and technical feasibility of a number of non-safety aeronautical communication (AAC and APC) solutions and business models in a 15 years timeframe in order to identify the commercial viability and technical feasibility of current and emerging connectivity solutions for the air transport, business aviation and government market segments.

Traditionally the Burst Time Plan (BTP) is always generated periodically in broadband satellite multimedia (BSM) system. Based on the analysis we find that periodical BTP generation (P-BTPG) method can not guarantee the delay performance and channel utilization efficiency simultaneously especially when the capacity requests arrived randomly. The optimized BTP generation (O-BTPG) method is given based on the optimal schedule period and schedule latency without considering the signaling overhead. Finally a novel asynchronous BTP generation (A-BTPG) method is proposed which is invoked according to users' requests. These three BTP generation methods are compared in a BSM system application scenario. The simulation verified our analysis. Simulation results show that A-BTPG can have a better delay performance than P-BTPG while guaranteeing overhead low. This method can be used in the ATM onboard switching satellite system and further more can be expended to digital video broadcasting-return channel satellite (DVB-RCS) system or IP onboard routing BSM system in the future.

The second-generation digital video broadcasting via satellite (DVB-S2) and the second-generation DVB interactive satellite system (DVB-RCS2) standards published by European Telecommunications Standards Institute (ETSI) have been dominating the global high-throughput satellite (HTS) communications market for recent five years. ETSI provisioned a technical report (TR) ETSI TR 101 545-4 as rudimentary guidelines for implementing a DVB-S2/DVB-RCS2 satellite system with security functions. Based on the ETSI guidelines, this paper depicts security implementations for a scenario of several distributed hub gateway stations which was unincorporated in the TR. Moreover, several optimizations and modifications were made to improve correctness and efficiency. A top-level star network security architecture, a hub security architecture, a return channel satellite terminal (RCST) security architecture, encrypted frame structures, authentication, and key distribution are described in this paper. The test results shew a less than 9% payload data rate decrease for the given security system in comparison to the unencrypted, proving the same speed performance level as the insecure commercial HTS ground infrastructure.

Interference analysis is crucial for the frequency sharing between satellite services according to the regulations and recommendations of International Telecommunications Union (ITU). For the fixed-satellite service (FSS) earth stations of our neighboring country in 8025–8400 MHz frequency band, the interference problems of FSS earth stations into earth exploration-satellite (EESS) service earth stations in specific link scenario are discussed via theoretical analysis and simulation calculation in this paper. The simulation results show that the interference of FSS earth stations into EESS earth stations currently registered at ITU meets the limit value of the recommendations, however the interference into the assumed EESS earth station cannot meet the limit value. The analyzed and simulated results can be references for the international coordination between the earth exploration satellite systems and communication satellite systems of neighboring countries in this band.

Stimulated by industrial developments towards personal communications links via constellations of non-geostationary (NGSO) satellites, the Administrative Radio Conference of 1992 made allocations to the mobile-satellite service (MSS) in the range 1-3 GHz, but no specific provision for the feeder-links to and from such constellations was made at that time, other than to recognise that Radio Regulation (RR) No. 22 allows bands allocated to the fixed-satellite service (FSS) to be used for the feeder-links of other space services. The subsequent increase in the pace of development prompted the World Radiocommunication Conference of 1993 (WRC-93) to request the ITU-R to carry out interference studies in all FSS bands below 30 GHz, to provide a basis for WRC-95 to take appropriate decisions regarding the spectrum for the feeder-links. The ITU-R Study Group 4 therefore investigated the frequency sharing problems which would potentially occur if NGSO MSS feeder-links were implemented alternatively in the 4-7 GHz range, the 11-16 GHz range and the 18-30 GHz range. The paper outlines the scenarios studied, gives examples of the quantitative results obtained, indicates the principal conclusions and summarises the relevant outcomes from WRC-95.

The 18.6–18.8 GHz band is utilized extensively for scientific uses. Passive microwave measurements in this frequency range are critical for weather forecasting and studies of climate and environmental impacts. This band, however, is shared with commercial communication systems that operate under the Fixed Satellite Service (FSS). FSS communication is used mostly for satellite TV broadcasting, and by a small number of Very Small Aperture Terminal (VSAT) systems. The Radio Regulations of the International Telecommunication Union (ITU) limit the level of FSS transmitted powers in order to avoid interference to passive sensors that operate under the Earth Exploration Satellite Service (EESS). However, Radio Frequency Interference (RFI) affecting spaceborne microwave radiometers such as WindSat, AMSR2 and GPM-GMI at 18 GHZ has been observed and documented for several years since 2010. Calculations considering sea surface reflection show that the observed RFI is consistent with or higher than what could be expected even from the limited level of transmitted power from the FSS. The IEEE Geoscience and Remote Sensing Society (GRSS) has brought this problem to the attention of the ITU Radiocommunication Sector (ITU-R) Study Groups, in view of impending decisions that could potentially dramatically increase the use of this band by commercial operators. The contributions by IEEE GRSS to ITU-R will be presented and various issues involved will be discussed.

The continuous transverse stub (CTS) technology incorporates the use of coaxial lines to produce effective microwave antenna structures that radiate an omnidirectional pattern with high efficiency and low return loss. In this paper a two-element coaxial CTS antenna array is designed to operate in the C-band with improved efficiency and gain. The proposed prototype of the C-band antenna, with design operating frequencies –5.18, 6.536 and 7.42 GHz, finds numerous applications in C-band satellite communications. During simulation, the efficiency at these frequencies had been observed to be 89.5, 87.6 and 95.9% and their corresponding gains were observed to be 7.54, 5.24 and 7.51 dB, respectively. The measured results of the C-band antenna prototype for the above stated frequencies were observed to be 5.185, 6.845 and 7.313 GHz, respectively. This antenna can be used in INSAT/super extended C-band, fixed-satellite services which include space to earth, earth to space as well as mobile satellite services. The radiation of the designed structure is omnidirectional in the horizon plane, with minimum return loss. These simple and low-cost coaxial CTS structures can be adopted in wireless communication systems.

In this paper, we consider the frequency sharing feasibility of Fixed Satellite Service (FSS) with Microwave Landing System (MLS) allocated in the C-band. On the basis of characteristics of MLS and FSS suggested by ITU and safety standards of MLS by ICAO, three interference scenarios are built and numerical simulations are carried out for investigating the frequency sharing between the two systems. From the simulation results, we calculate the separation distance between MLS and FSS ground antennas, required for frequency sharing by employing standard protection limits regulating the interference to noise ratio (I/N) of the receiver.

Satellite communication networks play a significant role to worldwide telecommunication infrastructure providing direct-to-mobile user satellite services. Quality of Service requirements should be taken into account in the satellite power allocation schemes that follow the channel variations. Employing a shadowed Rician model for land mobile satellite communications and an adaptive modulation scheme, closed form expressions are derived for the optimal power allocation and the effective capacity. The effective capacity of the system under specific Quality of Service constraints is maximized. Finally, the impact of the elevation angle on the power allocation and the effective capacity is investigated.

Communication satellites have a much longer propagation delay than terrestrial communication networks such as cellular or WiFi. In addition, as the carrier frequency moves up, mobile satellite communications show worse performances than the conventional fixed satellite communications. The mobile satellite service (MSS) has not been actively pursued with long latency at high-frequency bands for future applications. In this paper, the adverse impact of long propagation delay in the conventional satellite system is investigated with various user mobility and Doppler-shifted carrier frequency. The satellite network is modeled as a basic delayed feedback channel system and the communication performance is analyzed under delayed channel state information (CSI) for assessing the system feasibility in mobile conditions. The results of performance analysis are provided at high-frequency bands with high-speed user movement, specifically on the outage probability and the channel capacity exploiting three types of channel models: conventional land mobile satellite (LMS) channel models of E. Lutz and C. Loo, and Nakagami fading model. In the circumstance with various user speeds, system performances are evaluated with different propagation delays in the LMS channel models and for line-of-sight (LOS) components in the Nakagami fading. In addition, the conventional models are compared depending on different altitudes for geostationary orbit (GEO), medium earth orbit (MEO), and low earth orbit (LEO) satellites, as well as high-altitude platforms (HAP).

The Highly Elliptical Orbit (HEO), contrary to Geostationary Earth Orbit (GEO), is projected to cover landmasses of Northern Hemisphere and also the Polar Regions for both Fixed (FSS) and Mobile Satellite Service (MSS). The HEO configuration was chosen by the Soviet Russian Space Authorities for the Molnya and Tundra system in order to facilitate launching from their territory and ensure coverage throughout the entire former USSR territory. Examples of HEO systems are Molnya, Tundra, Loopus, Archimedes and Borealis of the El-lipso system. The Borealis configuration is a part of Ellipso hybrid satellite constellation, which has to be presented as a Hybrid Satellite Orbit (HSO). The HEO satellite constellation turned for 180 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">o</sup> will be able to cover territories of Southern Hemisphere including South Africa.

The growth in wireless communication services together with increasing demand has resulted in the scarcity of spectrum resources. Many researchers have attempted to address the scarcity problem by focusing on spectrum sharing to allow fixed satellite services (FSS) to coexist with other fixed services or other satellite communication systems. However, most secondary users are commercial systems, whose characteristics differ from military systems such as tactical data links (TDLs). A TDL requires anti-jamming capability and multiple operations support; thus, most TDLs use multiple frequency hopping (FH) patterns, known as multinet. To the best of our knowledge, no research has focused on the coexistence of FSS and TDL to date. In this paper, we verify whether spectrum sharing will facilitate the coexistence of FSS and FH-TDL. First, we propose FH-TDL with a spectrum use rule and a new FH method to reduce the pulse collision probability. We then prove that interference from FH-TDL to FSS is permissible. Instead of analyzing interference from FSS to FH-TDL, we simply consider the worst case, i.e., that a signal experiencing interference by FSS is always subject to collisions. We analyze the pulse collision probability under the worst case by constructing the mathematical models rather than using simulation. The numerical results show that the use of appropriate values for the weight parameter enables the proposed FH method to improve the pulse collision probability of FH-TDL.

This paper presents study results for an interference monitoring scheme between satellite and cellular systems in the 28 GHz band. For adequate monitoring sensitivity, we used feature detection techniques such as a frequency multiplying function and a use of Cyclic Prefix (CP) attached in the OFDM signal. The proposed scheme permits the estimation of the power ratio of satellite and cellular signals, together with the input Carrier to Noise power ratio. The scheme is made possible by the fact that an interference signal can be treated like input thermal noise in the feature detector, as verified by computer simulation. Aiming for a realistic examination of their performances, an already commercialized mobile satellite service was presumed as the satellite system. The assumed specifications of the cellular system were based on the presently operating LTE system, which is commonly named Proof-of-Concept (PoC). The computer simulation indicated that an estimated power ratio of 20 dB is attainable with high accuracy.

Since 2016, when the Federal Communication Com-mission (FCC) initiated its first Processing Round for U.S. Market Access, more than twenty distinct entities applied for authority to launch and operate fixed satellite service (FSS) satellite constellations consisting of more than 70,000 satellites [1]. One of the fundamental challenges, from a technical, regulatory and financial perspective, of these systems is a low-cost, consumer broadband, user terminal solution that complies with today's strict regulations. At the national level, the FCC defines require-ments for satellite systems in its 47 CFR Part 25 Rules. The most pertinent of these regulations for user terminals are: power flux density (25.208), earth station gain mask requirements (25.209), offaxis equivalent isotropically radiated power (EIRP) density envelope requirements (25.218), and requirements for Earth stations in motion (ESIMs) (25.228). These regulations were first developed with geostationary (GSO) systems in mind, and have evolved to consider the increase in number of non-geostationary (NGSO) systems and megaconstellations. At the international level, the International Telecommunications Union (ITU) sets forth power flux density (PFD) and equivalent power density (EPFD) requirements in Article 22 of the Radio Regulations (RR). This work offers an overview of modern phased array user terminal technology (namely analog, digital and hybrid beamforming techniques), today's manufacturers of phased array technology, as well as the national and international regulations with which these devices must comply.