Broadcasting Satellite Service Research Articles

Forecasting Ionospheric TEC Changes Associated with the December 2019 and June 2020 Solar Eclipses: A Comparative Analysis of OKSM, FFNN, and DeepAR Models

This paper presents forecast and investigation of the variation in ionospheric Total Electron Content (TEC) during the solar eclipses (SEs) of December 2019 and June 2020 using three different methods: Deep Autoregressive model (DeepAR), Feed-Forward Neural Network (FFNN), and Ordinary Kriging-based Surrogate Model (OKSM), and the TEC data predicted by DeepAR, FFNN, and OKSM were compared with the actual TEC during the observation days. The study was conducted based on GPS data taken from the IISC receiver located in Bangalore, India, during the SEs which happened on 26.12.2019 and 21.06.2020. The TEC data were examined to assess the effect of solar eclipses on TEC values. Eighty-day prior TEC data for the IISC station are gathered from IONOLAB servers along with the other parameter data like Dst, Ap, F10.7, and Kp taken from OMNIWEB servers which were used to predict TEC. The reliability of the forecasted results is evaluated using numerical factors like Normalized Root Mean Square Error (NRMSE), Correlation Coefficient (CC), Root Mean Square Error (RMSE), Mean Absolute Error (MAE), and R-squared. The study demonstrates the usefulness of combining multiple methods for analyzing TEC variations during SEs and highlights the potential of OKSM, FFNN, and DeepAR models for studying TEC variation in the same context. The findings may be useful for satellite broadcasting and navigational services and for further research into the influence of solar eclipses on the TEC changes.

A miniaturized quintuple-band frequency selective surface based on enclosed cross slots

Abstract This article presents a low-profile quintuple-band frequency selective surface (FSS) that is designed as a sub-reflector for applications including satellite systems (C band), EPR (electron paramagnetic resonance) spectrometers, motion and traffic light crossing detectors (X band), Direct Broadcast Satellite and broadcasting satellite service (Ku band), and shortrange applications (K band). The dimensions of the miniaturized unit cell 0.08λ0×0.08λ0×0.012λ0, where, λ0 is the free-space wavelength corresponding to the lower cut-off frequency. There are five stop bands, and frequencies at which they resonate are 6.3, 7.06, 9.30, 11.2, 14.0, and 18.64 GHz. The fractional bandwidths (FBW) of these bands are 62.6, 7.5, 9.2, 11, and 11.69%, respectively. Additionally, as a result of the structure’s four-fold symmetry, it exhibits a good polarization-insensitive response as well as a stable response in both the TE and TM modes. Full-wave simulation is performed on the structure, after which an equivalent circuit model is constructed.

Beamforming and Band Allocation for Satellite and High-Altitude Platforms Cognitive Systems

In this letter, we consider a cognitive radio network consisting of broadcast satellite service (BSS), high-density fixed-satellite service (HDFSS), and high-altitude platforms (HAPs) systems. The spectrum utilization within a satellite beam coverage is increased by deploying extra HAPs in the pre-determined hot-spot regions to existing cognitive systems in which the BSS and HDFSS share frequency bands. Since the multiple network nodes simultaneously employ the same frequency band, there exists a challenge to efficiently mitigate the interference between them. Therefore, we propose an iterative precoding and band allocation algorithm for multi-antenna HAPs to maximize the network data rate. In addition, we present other low-complexity techniques and compare them through simulation results.

Active frequency selective surface with switchable response for satellite communications in X and Ka bands

This article proposes an active frequency selective surface (FSS) with application to satellite multi-band antennas in X and Ka bands. The FSS offers two reflective bands at 20 and 30 GHz (downlink and uplink frequencies of broadband communication satellites in Ka-band) under one biasing state, whereas the frequency characteristics are switched in X-band (between 9 and 12 GHz, frequencies used for broadcast satellite services and space exploration) under the second biasing state. The unit cell of the FSS consists of three metallization layers, including four PIN diodes on the bottom layer that provide reconfigurability in X-band. The FSS performance has been analyzed using an equivalent circuit model diagram, which provides a better understanding of the operation principle. The proposed FSS exhibits a robust transmission response for incidence angles up to 40°. Several samples of the FSS formed by a 2 × 4 cell array have been fabricated and measured in a waveguide simulator to confirm the results of the electromagnetic simulations at the lower operating frequencies.

Coexistence of Satellite Ground Stations in Teleport Facilities: Interference Assessment, Real Application Scenario and Measurements.

This article introduces a unified and detailed methodology for interference assessment between coexisting fixed satellite service (FSS) and broadcast satellite service (BSS) with spectrum sharing at the Ka-band. The interference analysis is presented along with a step-by-step algorithm for the calculation of the carrier-to-interference ratio (CIR). The proposed procedure takes into consideration the near-field effect of ground-satellite-terminal antennas since these may reside at very close distances. Furthermore, numerical results are delivered so as to assess the CIR in relation to the relative geometry and the technical characteristics of the satellite terminals. A real application scenario is also provided along with measurements so as to validate the recommended methodology. Finally, mitigation techniques are proposed for the protection of the victim stations and operation under harmful interference conditions.

Ramalan Pelemahan Hujan di Malaysia Menggunakan Data TRMM

Rainfall is observed as a main contributing factor in the degradation of electromagnetic signal for frequency above 10GHz through absorption and scattering, resulting a weak or fading signal. Broadcasting satellite service operates in Ku band (12GHz to 18GHz) is widely used has caused congestion, therefore Ka band is exploited to meet the customer demand. However, the rain attenuation effects on Ka band are higher than Ku band. In this study, the rain attenuation effects of Ka band downlink signal of the Measat-5 satellite are analysed to assess the rain fade properties using TRMM 3B42 data for eleven (11) years from January 2009 until December 2019 for fourteen study areas. All data are processed to obtain 1-minute integration data using Segal Model and the prediction of rain attenuation are implemented using ITU-R P.618-13 model. This study summarizes, there are three, (3) main factors that influence the impact of rain attenuation, namely the value of specific attenuation, receiver station altitude and elevation angle of the satellite signal receiver antenna. The signal availability impact on rain attenuation shows, eight (8) study areas could receive 99.90% of service readiness, while the rest at 99.00% to comply with the ITU unavailability requirements. Overall, the value of rain attenuation on the West Coast of Peninsular Malaysia is smaller than the East Coast of Peninsular Malaysia and the value of rain attenuation in the East Coast of Peninsular Malaysia is closer to the value of rain attenuation in Sabah and Sarawak.

Introduction of the Advanced Meteorological Imager of Geo-Kompsat-2a: In-Orbit Tests and Performance Validation

Geo-Kompsat-2A (Geostationary-Korean Multi-Purpose SATtellite-2A, GK2A), a new generation of Korean geostationary meteorological satellite, carry state-of-the-art optical sensors with significantly higher radiometric, spectral, and spatial resolution than the Communication, Ocean, and Meteorological Satellite (COMS) previously available in the geostationary orbit. The new Advanced Meteorological Imager (AMI) on GK2A has 16 observation channels, and its spatial resolution is 0.5 or 1 km for visible channels and 2 km for near-infrared and infrared channels. These advantages, when combined with shortened revisit times (around 10 min for full disk and 2 min for sectored regions), provide new levels of capacity for the identification and tracking of rapidly changing weather phenomena and for the derivation of quantitative products. These improvements will bring about unprecedented levels of performance in nowcasting services and short-range weather forecasting systems. Imagery from the satellites is distributed and disseminated to users via multiple paths, including internet services and satellite broadcasting services. In post-launch performance validation, infrared channel calibration is accurate to within 0.2 K with no significant diurnal variation using an approach developed under the Global Space-based Inter-Calibration System framework. Visible and near infrared channels showed unexpected seasonal variations of approximately 5 to 10% using the ray matching method and lunar calibration. Image navigation was accurate to within requirements, 42 µrad (1.5 km), and channel-to-channel registration was also validated. This paper describes the features of the GK2A AMI, GK2A ground segment, and data distribution. Early performance results of AMI during the commissioning period are presented to demonstrate the capabilities and applications of the sensor.

Design of a wideband right‐handed circularly polarized array of miniaturized mushroom‐shaped antennas for direct broadcast satellite application

AbstractIn this study, a wideband right‐handed circularly polarized (RHCP) array of microstrip patch antennas, for direct broadcast satellite (DBS, 12.2‐12.7 GHz) services have been presented. The single element of the array is a two‐dimensional mushroom‐shaped fractal antenna of resonating frequency 12.49 GHz and an impedance bandwidth of 1.12 GHz. The proposed single element is designed by etching a pair of Minkowski square boxes in one of the two opposite sides of a regular octagon. Furthermore, a thin slot of length equal to one side of the regular octagon is placed in‐between the two Minkowski boxes, which results in the proposed mushroom‐shaped radiating element. The proposed four‐element linear array resonates at 12.47 GHz and gives an impedance bandwidth of 1.04 GHz. The feed network of the array is designed in such a manner to make the array structure very compact. The fabricated single element gives an RHCP gain of 5.25 dBic and its corresponding circular Polarization (CP) bandwidth of 200 MHz. The array gives an RHCP gain of 11.59 dBic and a CP bandwidth of 460 MHz. The measured CP bandwidth of the fabricated array prototype ensures 92% coverage of the entire DBS band with circularly polarized wave, and hence can be used for its related applications.

Interference into radio broadcast satellite uplinks

Radio frequency interference into satellite transmission channels is a matter of concern. There have been many studies of this subject by the ITU (International Telecommunications Union) particularly to mobile user receivers in the satellite radio broadcasting services by IMT (International Mobile Telecommunications) transmitters, since such receivers have high sensitivities (e.g., downlink channel system noise temperatures of under 100 deg. Kelvin) and provide Satellite Digital Audio Radio Service (SDARS) quality using relatively low satellite signal levels on the ground. Recently, proposals have been made by future low orbit satellite constellations, IMT and terrestrial interconnection systems to share radio frequency bands used by the transmission uplinks to radio broadcasting satellites. The broadcasting satellite uplink transmission channel at 7 GHz has typical system noise temperatures of 900 deg. Kelvin followed by very high electronic and antenna amplification. The overall system transmission design is generally set so the satellite broadcast uplink C/N does not appreciably degrade the downlink C/N, since the downlink simultaneously serves than 35 million mobile users with satellite radio service in North America. This paper describes the effect of potential interference into a satellite radio broadcast service from in-band and adjacent band transmissions and from associated intermodulation products by sharing uplink frequency spectrum transmitters. The analysis shows that such sharing services should be carefully arranged in the radio frequencies utilized and limited in flux densities impinging the geostationary orbital arc so harmful interference to radio broadcast satellite services does not occur.

Extremely High Frequency (EHF) Bands for Future Broadcast Satellite Services: Opportunities and Challenges

The exploitation of the bandwidth portions in the millimeter wave domain, namely extremely high frequencies (EHFs) will open new perspectives to future satellite services, in particular for high quality TV broadcasting and multimedia content delivery. The present work aims at surveying the opportunities and challenges of EHF exploitation for broadband satellite applications in the broadcast framework. Theoretical capacity evaluation confirms that EHF satellite links can offer unprecedented data-rates, clearly superior than that actually provided by Ku and Ka-bands. However, some crucial issues are still to be solved, mainly in terms of mitigation of tropospheric propagation impairments and appropriate waveform design. Link and capacity analysis will be the basis for the investigation of future application scenarios of broadcast EHF satcoms, namely high-definition TV (HDTV) and ultra-HDTV, with particular emphasis to 4K and 8K video formats.

Composite right/left‐handed based compact and high gain leaky‐wave antenna using complementary spiral resonator on HMSIW for Ku band applications

In this communication, a novel compact high gain composite right/left-handed (CRLH) based leaky-wave antenna (LWA) is presented at Ku band. A half-mode substrate-integrated waveguide incorporated with a suitably oriented complementary quad spiral resonator (CQSR) is used to achieve a CRLH LWA. The unit cell is realised by a CQSR in such a way that the orientation of spirals exhibits higher leakage loss having a minimum cross coupling between them. The antenna is capable of scanning backward to forward along with a broadside direction in visible space. The proposed configuration has a length of 4.85 λ 0 which can scan within the frequency range of 13.5-17.8 GHz having a beam scanning range of 86° (-66° to 20°) and a maximum gain of 16 dBi. The simulated reflection coefficient of the proposed antenna is below -10 dB throughout the working frequency range with a side-lobe level of below -10 dB. The designed prototype is more compact in nature having high gain, fair scanning range, and good cross-polarisation level along with simpler design methodology and tuning capability to enhance the gain as well as radiation efficiency maintaining a fixed size. The proposed antenna could be a promising candidate in Ku-band applications like fixed satellite services, and broadcast satellite services etc.

The Optimization Design of a Novel Slotted Microstrip Patch Antenna with Multi-Bands Using Adaptive Network-Based Fuzzy Inference System

This paper attempts to apply an adaptive network-based fuzzy inference system (ANFIS) for analysis of the resonant frequency of a single-layer single-patch microstrip rectangular patch antenna with two equal size slots which are placed on the patch in the form of parallel to resonance edges. The resonant frequency is calculated as the position of the slots is shifted from the right endpoint to the left endpoint on the patch between −4.2 mm ≤ Xslot ≤ 4.2 mm with the steps of 0.1 mm. The designed antenna is proposed for downlink of X band satellite, broadcasting satellite service, fixed-satellite service uplink, satellite (Earth-to-space), radio navigation, mobile-satellite (Earth-to-space), and KU band which can be achieved at the resonant frequencies of 7.2 GHz, 12.2 GHz, 14.6 GHz, 17.5 GHz and 19.3 GHz. Next, High Frequency Electromagnetic Field Simulation software (ANSYS HFSS) results for the prototype microstrip antenna are compared with the values obtained through ANFIS system. It can be concluded that the adaptive network-based fuzzy inference system in such designs can be conveniently used due to fuzzy system’s high approximation capability and much faster convergence rate. The best results for our ANFIS system can be obtained if Gaussian membership is used which leads to the mean absolute error of 1.4653.

Cooperative Coverage Extension in Vehicular Land Mobile Satellite Networks

We study the application of random linear network coding (RLNC) for cooperative coverage extension in land mobile satellite (LMS) vehicular networks. We perform an analytical assessment of the limits of cooperation in the presence of both a satellite and a terrestrial repeater (gap filler). Using the max-flow min-cut theorem, we derive exact expressions and closed-form lower bounds on the coverage in a setup of practical interest. Furthermore, we propose a practical implementation of the RLNC cooperative approach for the Digital Video Broadcasting—Satellite services to Handheld (DVB-SH) standard. We evaluate numerically the performance of the proposed protocol using a simulator based on physical-layer abstraction (PLA) and widely adopted propagation channel models for both the satellite and the terrestrial segments. Our simulation results show that the proposed scheme extends the coverage with respect to a system in which simple cooperative relaying is used, making a more efficient use of the terrestrial channel resources. In addition, the proposed solution can help keep a relatively low outage probability while limiting the number of required gap fillers.

Impact of Interference on 12GHz Band Broadcasting Satellite Services in terms of Increase Rate of Outage Time Caused by Rain Attenuation

Impact of Interference on 12GHz Band Broadcasting Satellite Services in terms of Increase Rate of Outage Time Caused by Rain Attenuation

English

Satellite communication systems that work at frequency above 10 GHz can be severely affected by atmospheric phenomena being the most important the attenuation due to rain. In order to satisfy availability and quality of service specifications, fade mitigation techniques are designed and tested using experimental time series of rain attenuation. These time series are synthesized from the estimated attenuation of rain to be exceeded for some percentages of an average year. This paper presents a statistical model prediction based on peaks over threshold to describe the rain attenuation exceeded for 0.01% of an average year for broadcast satellite services at Ku band. Then, the predict attenuation is described by Pareto distribution and the time between fades by a nonhomogeneous Poisson process in monthly periods. This model is valid for elevation angles from 18o to 42o degrees and reflects the climate change over the years.

Cognitive Zone for Broadband Satellite Communications in 17.3–17.7 GHz Band

Deploying high throughput satellite systems in Ka band to accommodate the ever increasing demand for high data rates hits a spectrum barrier. Cognitive spectrum utilization of the allocated frequency bands to other services is a potential solution. Designing a cognitive zone around incumbent broadcasting satellite service (BSS) feeder links beyond which the cognitive fixed satellite service (FSS) terminals can freely utilize the same frequency band is considered in this paper. In addition, we show that there is a rain rate called rain wall, above which cognitive downlink communications become infeasible.

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.

Novel Hybrid Antenna for Broadcasting Satellite and Terrestrial HD-TV

High-definition television (HD-TV) is available via satellite broadcast and terrestrial HD-TV services. However, antennas that can receive HD-TV signals using different carrier waves (i.e., X band and UHF band) have not yet been designed. Therefore, in an effort to realize such an antenna, we created a slot aperture in the reflector of a typical Broadcasting Satellite (BS) antenna, and investigated its possible use as a UHF-band antenna element. Furthermore, a practical hybrid antenna for BS and terrestrial HD-TV was developed by implementing omnidirectional radiation in a parabolic reflector with a slot. This hybrid antenna exhibited excellent practical performance in a field test.

ANALYSIS OF BISTATIC SCATTERING DUE TO HYDROMETEORS ON SHF AND EHF LINKS IN A SUBTROPICAL LOCATION: A COMPARATIVE STUDY BASED ON THE RAIN CELL MODELS

The inevitable increase in radio interference within microwave systems continue to be of major concern as more of radio communication services compete with bandwidth assigned to the fixed service, fixed satellite service and broadcasting satellite service. Interference hampers coverage and capacity of these services often lead to the reduction in the signal to noise ratio at the receiving terminals. The existing global hydrometeor scatter model proposed by the International Telecommunication Union when applied to the tropical and subtropical location often leads to considerable inaccuracies due to the wide range of intense climatic and geographical nature of this region. In this study, the bistatic intersystem interference due to hydrometeors between satellite systems and terrestrial downlink receiver terminal systems in a subtropical station computation is based on the Awaka and Capsoni cell models. For the attenuation of both wanted and unwanted paths to the receiver, the existing model based on the specific attenuation has been modified to include the equivalent path length through rain in the estimation of the attenuation. Results obtained show that the Capsoni model exhibits the normal trend under a moist atmosphere with a gaseous attenuation more pronounced at frequencies greater than or equal to 30 GHz. Also at high rain rates greater than 70 mm/h and considering the rain with melting layer, up to about 70 dB difference was observed between transmission losses estimated using Awaka and Capsoni models at link probabilities ranging between 1-10 −3 % unavailability of the time.

A new performance metric for M-APSK receivers

Synchronization is a critical function that determines the overall performance and complexity of the receiver of any communications system. The implementation and evaluation of effective synchronization algorithms still comprises a challenging task that requires accurate testing methods, which are based on measurements collected at various processing stages. M-ary Amplitude-Phase Shift Keying (M-APSK) constellations are used in modern communications systems, such as digital video broadcasting and interactive broadband satellite services, due to their bandwidth efficiency characteristics. This paper presents a new metric that can be associated with the signal quality at various synchronization mechanisms used in M-APSK receivers. Apart from the metric's mathematical derivation, the paper presents various experimental results based on single (QPSK, 8PSK), two (16APSK) and three (32APSK) ring M-APSK schemes employed in DVB-S2 systems.