Multiple-input Multiple-output Satellite Research Articles

Transmit Power Optimization and Precoding Design in Multiuser Satellite MIMO Downlink With SINR Constraints

In this paper, a multi-user (MU) satellite Multiple-Input Multiple-Output (MIMO) downlink including a multi-beam GEO satellite and multiple terrestrial users is considered. In order to meet the signal to interference plus noise ratio (SINR) requirements of different users while minimizing the satellite transmit power, the onboard precoding problem is investigated. Zero forcing (ZF) and regularized zero-forcing (RZF) precoding are first adopted and it is found that they can satisfy the SINR constraints by multiplying by a power allocation matrix. The required power allocation matrix is divided into two types: equal power factor schemes and unequal power factor schemes, and they are derived separately, where Karush-Kuhn-Tucker (KKT) conditions are used in RZF unequal power factor scheme and a heuristic algorithm is proposed to optimize the regularization factor in RZF schemes to further reduce the transmit power. Then, a semi-definite programming beamforming (SDPBF) is proposed to jointly optimize precoding and power allocation matrices. The closed-form expressions of the transmit power of the above five precoding schemes are derived and their performance is compared in the simulation part. The research results show that under the same conditions, the performance of RZF is better than that of ZF, the unequal power factor scheme is better than the equal power factor scheme, and SDPBF has the best performance. Besides, it is also found that in addition to changing the precoding method, activating more beams will further reduce the transmit power.

Capacity Analysis of Terrestrial Antenna Array in Distributed Satellite MIMO Communication System

Multiple-Input Multiple-Output (MIMO) techniques are able to enhance the channel capacity by multiplexing the space dimension resources. By constructing distributed satellite MIMO scenarios, MIMO techniques can be potentially employed to satellite communication networks. In this paper, we study the capacity performance of a distributed satellite communication network with the MIMO scheme that contains two geostationary earth orbit (GEO) satellites and a terrestrial antenna array. Specifically, the model of two kinds of terrestrial antenna array, uniform linear array (ULA) and uniform circular array (UCA), are proposed and the coordinate representation of the array elements is provided by coordinate system transformation. Then, the analytical expressions of the system capacity with different antenna arrays are derived considering the rotation angle of the antenna array. The Min-Max ratio is investigated for both ULA and UCA to gain further insights of the system capacity performance. Finally, numerical simulations are provided to validate the analytical expressions, show the impact of the rotation angle and other system parameters on the capacity performance. The research results show that ULA is preferred for terrestrial users with fixed locations and the maximum channel capacity can be obtained through adjusting the rotation angle while UCA is not only suitable for fixed locations, but can also be used in mobile scenarios such as vehicles, ships to ensure the stability of the system capacity.

Compact and Free-Floating Satellite MIMO SAR Formations

We discuss a coherent synthetic aperture radar (SAR) formation where <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$N$ </tex-math></inline-formula> identical sensors transmit at the same time, code, and frequency. This is a particular multiple-input–multiple-output (MIMO) configuration, where the transmitted waveforms interfere together, resulting in an illumination pattern that randomly changes in space and time. Similar to the single-input–multiple-output (SIMO) formations, the diversity provided by the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$N$ </tex-math></inline-formula> receiver phase centers can be used to mitigate this interference and reduce the pulse repetition frequency (PRF) for achieving large swath coverage. The good point, in the MIMO case, is that the signal-to-noise ratio (SNR) gain of the system increases, theoretically, with the square of the number of elements. However, residual spurious sidelobes may appear as ghosts of the multiple illuminators. In practice, the power gain is to be optimized, together with ambiguity rejection, sidelobes, and azimuth resolution. The actual performances achievable by these formations in terms of impulse response function (IRF), SNR, and sensitivity to the precise positioning of the sensors are discussed theoretically and based on simulations.

Performance analysis of circularly polarized dual annular ring patch antenna for MIMO satellite application

ABSTRACT In this paper, a dual annular ring patch antenna with high isolation for Multiple Input Multiple Output (MIMO) Satellite application at 4 GHz is presented. The mutual coupling reduction and circular polarization are achieved by some perturbations in annular ring patch and microstrip stubs between antennas. These perturbations will excite two modes which is orthogonal ie. equal amplitude and phase shift to make it circularly polarized. The antenna design is fabricated on a substrate with permittivity 4.4 and 1.6 mm thickness. The simulated results are studied and analyzed for the proposed antenna. The isolation of better than 30 dB, axial ratio lower than 3 dB and gain of about 3.4 dB are obtained. The performance characteristics are simulated, measured and analyzed with different antenna parameters. The validated antenna shows that the simulated and measured results are in good agreement with each other.

System Modeling and Precoding Design for Multi-beam Dual-polarized Satellite MIMO System

Background: As the multimedia service develops and the transmission rate in terrestrial communication systems increases rapidly, satellite communication needs to improve the transmission rate and throughput. Multiple Input Multiple Output (MIMO) techniques can increase the system capacity significantly by introducing the space dimension, as the system bandwidth remains the same. Therefore, utilization of MIMO for satellite communications to increase the capacity is an important research topic. So MIMO techniques for multibeam satellite communications are researched in the dissertation. Objective: The goal of this work is improving the capacity of the satellite system. Multi-beam and dual-polarized technologies are applied to a satellite system to improve the capacity further. Methods: In this paper, we first introduce a multi-beam dual-polarized satellite multi-put and multiout (MBDP-S-MIMO) system which combines the full frequency multiplexing and dual-polarization technologies. Then the system model and channel model are first constructed. At last, to improve the capacity further, BD and BD-ZF precoding algorithms are applied to MBDP-S-MIMO and their performance is verified by simulation. Results: Simulation results show the performance of the BD precoding algorithm gets better with the growth of the XPD at the receiver and is almost not affected by the growth of the channel polarization correlation coefficient. In addition, with the growth of the users’ speed, the performance becomes worse. Conclusion: The multi-beam dual-polarized satellite MIMO system has high capacity, and it has certain application prospects for satellite communication.

Combined precoding for multiuser Multiple-Input Multiple-Output satellite communications

Applying Multiple-Input Multiple-Output (MIMO) techniques in satellite communications can increase data rates. However, new signal processing elements have to be taken into account to fully exploit the expected advantages of MIMO communications. In this paper, we evaluate different precoding techniques over the satellite channel. A performance comparison between several precoders in terms of Bit Error Rate (BER) and complexity is given for different channel realizations. Furthermore, a novel hybrid scheme for signal precoding is proposed that optimizes the computation for a required BER. The new scheme is based on the matrix condition number of the satellite MIMO channel.

Capacity Analysis and Optimization of Satellite MIMO System

Multiple-Input Multiple-Output (MIMO) technology is widely applied in terrestrial wireless communication system, which greatly increases the system capacity. Satellite communication system has many advantages such as wide coverage and strong flexibility. Therefore, how to make a better use of MIMO technology in satellite communication system has become a research hotspot in recent years. The purpose of this paper is to analysis the relationship between satellite MIMO system capacity and parameters of terrestrial antenna such as angle and distance. The parameters of terrestrial antenna were derived and calculated to keep a higher capacity for satellite MIMO system. Numerical analysis of system capacity performance before and after optimization was obtained, which proved the correctness of the theory proposed in this paper.

MIMO for Mobile Satellite Digital Broadcasting: From Theory to Practice

This paper presents the detailed design and the key system performance results of a comprehensive laboratory demonstrator (testbed) for a hybrid satellite/terrestrial S-band mobile digital broadcasting system. The physical layer is based on an enhanced version of the digital video broadcasting—satellite to handheld (DVB-SH) standard, exploiting dual-polarization multiple-input–multiple-output (MIMO) technology. This complete digital MIMO demonstrator, which is the first of its kind, allows for an in-depth verification and optimization of the MIMO techniques applied to satellite broadcasting networks. Moreover, this demonstrator allows for complementing and confirming the theoretical or simulation-based findings published thus far. It is shown that dual-polarization MIMO diversity is able to provide remarkable gains in terms of satellite/terrestrial transmit power reduction and/or capacity increase compared with more conventional non-MIMO solutions. It is also demonstrated that the adoption of a relatively simple spatial multiplexing MIMO technique represents the best way to grasp these gains. This paper provides an extensive set of laboratory measurement results for existing stochastic satellite and hybrid MIMO channels, as well as results based on an S-band satellite-measured dual-polarization time series recently collected during a campaign sponsored by the European Space Agency. Results obtained using MIMO techniques are also compared with a dual- and single-polarization single-input–single-output (SISO) DVB-SH benchmark system and with computer simulation results.

MIMO satellite communication with accelerated dual paths asynchronous design

This paper presents a novel asynchronous design approach for multiple input multiple output (MIMO) satellite communication (SatCom) systems. One of the main challenges for MIMO SatCom systems is that these are prone to transient faults that typically are attributable to radiation hazards. Hence, instead of using conventional synchronous circuits, we conceive our design using asynchronous circuits since it inherently has a high tolerance to transient fault. Additionally, we adopt accelerated dual paths (ADP) design into our system. By carefully arranging the data flow between the two paths, the ADP design approach can help to further accelerate the asynchronous system and increase the reliability of the system by circumventing transient faults induced delay, as well as tolerating latch-ups and other permanent faults. The numerical results show that this design approach provides promising results. For example, the proposed design can decrease the delay overhead of the entire system from 43.5 to 19.8 % at the fault rate of 400/clock cycle.

The Channel Capacity of Dual-Polarized MIMO Mobile Satellite System

Applying Multiple-Input Multiple-Output (MIMO) technology in terrestrial wireless networks can obtain large capacity gain. Therefore, MIMO technology is widely applied in satellite communication system, in which orbital positions are increasingly crowded and frequency resources are of shortage. This paper attempts to research on channel capacity in 2×2 dual-polarized MIMO mobile satellite (DMMS) system and discovers that when XPD (Cross Polarization Discrimination) is above zero, the channel capacity increases approximately linearly with the XPD within certain range. Adding Ricean factor K in consideration of its special features,the system’s capacity increases with the Ricean factor K. Simulation results demonstrate that the application of MIMO technology in satellite mobile communication system can improve the channel capacity significantly, providing great support for the development of future satellite MIMO technology.

Capacity and Error Rate Analysis of MIMO Satellite Communication Systems in Fading Scenarios

In this paper, we investigated the capacity and bit error rate (BER) performance of Multiple Input Multiple Output (MIMO) satellite systems with single and multiple dual polarized satellites in geostationary orbit and a mobile ground receiving station with multiple antennas. We evaluated the effects of both system parameters such as number of satellites, number of receive antennas, and SNR and environmental factors including atmospheric signal attenuations and signal phase disturbances on the overall system performance using both analytical and spatial models for MIMO satellite systems. DOI: http://dx.doi.org/10.11591/ijece.v4i4.5349

Spatial Dynamic Wideband Modeling of the MIMO Satellite-to-Earth Channel

A novel MIMO (multiple input multiple output) satellite channel model that allows the generation of associated channel impulse response (CIR) time series depending on the movement profile of a land mobile terminal is presented in this paper. Based on high precise wideband measurements in L-band the model reproduces the correlated shadowing and multipath conditions in rich detail. The model includes time and space variant echo signals appearing and disappearing in dependence on the receive antenna position and movement, and the actual azimuths and elevations to the various signal sources. Attenuation and path delays relative to the hypothetical line of sight (LOS) ensure usability for ranging purposes. Parameters for car and pedestrian applications in urban and suburban environments are provided. The channel characteristics are determined independently of the transmitted signal. Therefore the usability, for example, for GPS and GALILEO, as well as wideband communication services from hovering platforms, is given.

MIMO channel modeling and transmission techniques for multi-satellite and hybrid satellite–terrestrial mobile networks

The Quality of Service (QoS) in land mobile satellite (LMS) communications drops drastically in the presence of shadowing and multipath fading. This paper studies two promising multiple-input multiple-output (MIMO) schemes, along with specific transmission techniques, aimed at overcoming this problem. First, specific proposals for a dual-satellite distributed MIMO scheme are studied based upon delay-tolerant and spectral-efficient schemes. As a second alternative, a hybrid satellite–terrestrial scheme is studied with specific proposals for MIMO processing. In order to carry out a performance assessment the paper addresses related MIMO satellite propagation channel modeling issues which lead to a new mathematical model to accommodate the multi-satellite transmission. In both cases, we quantify and conclude the MIMO gains in terms of bit error rate (BER) and spectral efficiency for urban and suburban environments. The transmitted air-interfaces in both proposed MIMO schemes are DVB-SH standard compatible. The analytical results have been validated by means of Monte Carlo simulations.

Multi-Satellite MIMO Communications at Ku-Band and Above: Investigations on Spatial Multiplexing for Capacity Improvement and Selection Diversity for Interference Mitigation

This paper investigates the applicability of multiple-input multiple-output (MIMO) technology to satellite communications at the Ku-band and above. After introducing the possible diversity sources to form a MIMO matrix channel in a satellite environment, particular emphasis is put on satellite diversity. Two specific different topics from the field of MIMO technology applications to satellite communications at these frequencies are further analyzed: (i) capacity improvement achieved by MIMO spatial multiplexing systems and (ii) interference mitigation achieved by MIMO diversity systems employing receive antenna selection. In the first case, a single-user capacity analysis of a satellite MIMO spatial multiplexing system is presented and a useful analytical closed form expression is derived for the outage capacity achieved. In the second case, a satellite MIMO diversity system with receive antenna selection is considered, adjacent satellite cochannel interference on its forward link is studied and an analytical model predicting the interference mitigation achieved is presented. In both cases, an appropriate physical MIMO channel model is assumed which takes into account the propagation phenomena related to the frequencies of interest, such as clear line-of-sight operation, high antenna directivity, the effect of rain fading, and the slant path lengths difference. Useful numerical results obtained through the analytical expressions derived are presented to compare the performance of multi-satellite MIMO systems to relevant single-input single-output (SISO) ones.

Low Elevation Wideband Land Mobile Satellite MIMO Channel Characteristics

This paper presents wideband characteristics of a low elevation, land mobile, single satellite, dual circularly polarized, multiple-input multiple-output (MIMO) radio propagation channel. The work is based on S-band measurements using an artificial platform to represent the satellite, situated on a hilltop, to a mobile vehicle located in three environments: tree-lined road, suburban and urban. First and second order statistics and inter-tap cross-correlations are derived for both large and small scale fading, over the delay and combined spatial/polarization domains from the measured 2times2 MIMO matrix channel data. The work is aimed towards further development of a valid wideband land mobile satellite (LMS) MIMO channel model. Such systems may form the next generation of satellite delivered mobile broadband Internet services.