Radio Propagation Channel Measurements for Multi-Antenna...

102 IEEE Antennas and Propagation Magazine, Vol. 56, No. 6, December 2014

Radio Propagation Channel Measurements for Multi-Antenna Satellite Communication

Systems:ASurvey

Paraskevi Petropoulou1, Emmanouel T. Michailidis1, Athanasios D. Panagopoulos2, and Athanasios G. Kanatas1

1Department of Digital Systems, School of Information and Communication TechnologiesUniversity of Piraeus

80 Karaoli & Dimitriou St., 18534, Piraeus, GreeceTel: +30 210 414 2759; Fax: +30 210 414 2753E-mail: {ppetrop, emichail, kanatas}@unipi.gr

2School of Electrical & Computer EngineeringNational Technical University of Athens

9 Iroon Polytechniou St., 15780, Zografou, GreeceTel: + 30 210 7723842; Fax: +30 210 7723851

E-mail: [email protected]

Abstract

For the terrestrial infrastructure, the multiple-input multiple-output (MIMO) architecture is a key technology that has brought the wireless gigabit vision closer to reality. Satellite communication systems have not been immune from this wave of innovation, and theoretical and experimental efforts have recently been devoted to the investigation of the applicability of multiple-antenna techniques to these systems. This paper intends to highlight and critically present the most important results from measurement campaigns conducted to characterize the radio channel of multi-antenna satellite systems. Emphasis is given on the viability of MIMO technology over satellite, and the potential enhancements in terms of channel capacity and link reliability that can be achieved through spatial and/or polarization diversity. The confi gurations under investigation range from very simple single-input multiple-output (SIMO) systems, with multiple antennas only at the terrestrial receiver, to quite complex and challenging systems, such as dual-satellite multiple-input single-output (MISO) systems, and single-satellite dual-polarized MIMO systems. The spotlight is on land mobile satellite (LMS) systems in outdoor radio propagation environments. However, satellite-to-indoor reception is also included.

Keywords: Antenna measurements; communication channels; MIMO; multiple antennas; polarization diversity; satellite communication; spatial diversity

I. Introduction

The growing demand for comprehensive broadband and broadcast wireless communication services and

ubiquitous access have prompted the rapid deployment of sat-ellite networks that strongly support terrestrial backhaul net-works, and provide inherent multicast/broadcast capabilities and extensive as well as uninterrupted radio coverage to sta-tionary, portable, and mobile receivers. The development of next-generation systems envisages the synergetic integration of

heterogeneous terrestrial and satellite networks with differ ent capabilities, which give rise to new services, architectures, and challenges [1-3]. In this context, mobile satellite broad casting (MSB) systems operating at L (1 GHz to 2 GHz) and S (2 GHz to 4 GHz) frequency bands are a constitutive part of hybrid/integrated broadcasting systems. In these, the satellite segment delivers multimedia services to the largest part of the coverage area, and the complementary ground components (CGCs) retain service availability in highly shadowed areas, e.g., urban areas, and enhance indoor coverage.

ISSN 1045-9243/2012/$26 ©2014 IEEE

As new requirements for greater bandwidth, higher data rates, and improved quality of service (QoS) emerge, the mul-tiple-input multiple-output (MIMO) technology [4] has played an important role in revolutionizing terrestrial wireless net-works, leading to growing acknowledgement from the research community, industry, and wireless standardization bodies, e.g., IEEE 802.11n, 3rd Generation Partnership Pro ject 2 (3GPP2) ultra mobile broadband (UMB), and Digital Video Broadcasting - Second Generation Terrestrial (DVB-T2). To remain competitive with the terrestrial infrastructure and realize ultra-broadband (gigabit-speed) wireless, the application of MIMO techniques to satellite systems seems inevitable [5, 6]. This has gained great interest due to the stan dardization activities on the fi nalized DVB - Satellite to Handheld (DVB-SH) standard [7, 8], and the prospective DVB – Next Generation Handheld (DVB-NGH) [9, 10] stan dard. Figure 1 illustrates a typical structure of a MIMO DVB-SH hybrid satellite-terrestrial network.

Since channel characteristics directly determine the MIMO system’s performance [11], a detailed knowledge and accurate characterization of the MIMO satellite radio channel matrix, under various propagation conditions and scenarios, is crucial. The MIMO channel matrix captures the space-time nature of the radio propagation channel among the multiple antenna elements. Effi cient and reliable MIMO satellite sys-tems can then be designed and accurately tested before their implementation. Insight into the typical narrowband single-input single-output (SISO) land mobile satellite (LMS) chan-nel at L, S, Ku, and Ka frequency bands was acquired through research efforts over the last three decades, e.g., [12-22]. The application of multi-element antennas on either one or both sides of the radio link, forming multiple-input single-output (MISO), single-input multiple-output (SIMO), and MIMO satellite systems, has only recently begun to be theoretically and experimentally investigated by academia and space agen-

cies, as reported in [23-65]. Although measurement campaigns are expensive, time-consuming, and diffi cult to carry out, con-ducting real-world measurements and collecting measured channel data is a precondition for the successful validation of the results of preliminary theoretical efforts, and ascertains the benefi ts of employing multi-element antennas on satellite systems.

Motivated by this observation, this paper attempts to shed light on a variety of recent research activities with refer-ence to the characterization of the broadband satellite radio channel through measurement campaigns when multi-antennas are employed. After outlining the relevant background on MIMO satellite systems, this paper provides an overview of recent state-of-the-art multi-antenna land mobile satellite measurement campaigns, and the important milestones that have already been achieved. The review includes a presenta-tion of the measurement setup, and a brief critical description of the main results obtained from these measurements. Apart from considering the vehicular terminal case, the nomadic and pedestrian/handheld terminal cases are also examined, which invoke limited mobility and different antenna characteristics. A measurement campaign for the multi-antenna satellite-to-indoor channel is also included, where the propagation envi-ronment is more stringent than the typical land mobile satellite environment [66]. Since the Earth-space segment is not exclu-sively served by satellites [67, 68], this paper also discusses an indoor measurement campaign concerning a multi-antenna system based on high-altitude platforms (HAPs) [69], i.e., aircraft or airships fl ying in the stratosphere, capable of pro-viding wireless access over large coverage areas at low cost. The remainder of the paper is organized as follows. Sec-tion 2 briefl y discusses several MIMO techniques and their applications to the satellite domain. Section 3 presents various

Figure 1. A MIMO DVB-SH hybrid satellite-terrestrial network.

AP_Mag_Dec_2014_Final.indd 102 12/27/2014 2:02:03 PM

IEEE Antennas and Propagation Magazine, Vol. 56, No. 6, December 2014 103

Radio Propagation Channel Measurements for Multi-Antenna Satellite Communication

Systems:ASurvey

Paraskevi Petropoulou1, Emmanouel T. Michailidis1, Athanasios D. Panagopoulos2, and Athanasios G. Kanatas1

1Department of Digital Systems, School of Information and Communication TechnologiesUniversity of Piraeus

80 Karaoli & Dimitriou St., 18534, Piraeus, GreeceTel: +30 210 414 2759; Fax: +30 210 414 2753E-mail: {ppetrop, emichail, kanatas}@unipi.gr

2School of Electrical & Computer EngineeringNational Technical University of Athens

9 Iroon Polytechniou St., 15780, Zografou, GreeceTel: + 30 210 7723842; Fax: +30 210 7723851

E-mail: [email protected]

Abstract

For the terrestrial infrastructure, the multiple-input multiple-output (MIMO) architecture is a key technology that has brought the wireless gigabit vision closer to reality. Satellite communication systems have not been immune from this wave of innovation, and theoretical and experimental efforts have recently been devoted to the investigation of the applicability of multiple-antenna techniques to these systems. This paper intends to highlight and critically present the most important results from measurement campaigns conducted to characterize the radio channel of multi-antenna satellite systems. Emphasis is given on the viability of MIMO technology over satellite, and the potential enhancements in terms of channel capacity and link reliability that can be achieved through spatial and/or polarization diversity. The confi gurations under investigation range from very simple single-input multiple-output (SIMO) systems, with multiple antennas only at the terrestrial receiver, to quite complex and challenging systems, such as dual-satellite multiple-input single-output (MISO) systems, and single-satellite dual-polarized MIMO systems. The spotlight is on land mobile satellite (LMS) systems in outdoor radio propagation environments. However, satellite-to-indoor reception is also included.

Keywords: Antenna measurements; communication channels; MIMO; multiple antennas; polarization diversity; satellite communication; spatial diversity

I. Introduction

The growing demand for comprehensive broadband and broadcast wireless communication services and

ubiquitous access have prompted the rapid deployment of sat-ellite networks that strongly support terrestrial backhaul net-works, and provide inherent multicast/broadcast capabilities and extensive as well as uninterrupted radio coverage to sta-tionary, portable, and mobile receivers. The development of next-generation systems envisages the synergetic integration of

heterogeneous terrestrial and satellite networks with differ ent capabilities, which give rise to new services, architectures, and challenges [1-3]. In this context, mobile satellite broad casting (MSB) systems operating at L (1 GHz to 2 GHz) and S (2 GHz to 4 GHz) frequency bands are a constitutive part of hybrid/integrated broadcasting systems. In these, the satellite segment delivers multimedia services to the largest part of the coverage area, and the complementary ground components (CGCs) retain service availability in highly shadowed areas, e.g., urban areas, and enhance indoor coverage.

As new requirements for greater bandwidth, higher data rates, and improved quality of service (QoS) emerge, the mul-tiple-input multiple-output (MIMO) technology [4] has played an important role in revolutionizing terrestrial wireless net-works, leading to growing acknowledgement from the research community, industry, and wireless standardization bodies, e.g., IEEE 802.11n, 3rd Generation Partnership Pro ject 2 (3GPP2) ultra mobile broadband (UMB), and Digital Video Broadcasting - Second Generation Terrestrial (DVB-T2). To remain competitive with the terrestrial infrastructure and realize ultra-broadband (gigabit-speed) wireless, the application of MIMO techniques to satellite systems seems inevitable [5, 6]. This has gained great interest due to the stan dardization activities on the fi nalized DVB - Satellite to Handheld (DVB-SH) standard [7, 8], and the prospective DVB – Next Generation Handheld (DVB-NGH) [9, 10] stan dard. Figure 1 illustrates a typical structure of a MIMO DVB-SH hybrid satellite-terrestrial network.

Since channel characteristics directly determine the MIMO system’s performance [11], a detailed knowledge and accurate characterization of the MIMO satellite radio channel matrix, under various propagation conditions and scenarios, is crucial. The MIMO channel matrix captures the space-time nature of the radio propagation channel among the multiple antenna elements. Effi cient and reliable MIMO satellite sys-tems can then be designed and accurately tested before their implementation. Insight into the typical narrowband single-input single-output (SISO) land mobile satellite (LMS) chan-nel at L, S, Ku, and Ka frequency bands was acquired through research efforts over the last three decades, e.g., [12-22]. The application of multi-element antennas on either one or both sides of the radio link, forming multiple-input single-output (MISO), single-input multiple-output (SIMO), and MIMO satellite systems, has only recently begun to be theoretically and experimentally investigated by academia and space agen-

cies, as reported in [23-65]. Although measurement campaigns are expensive, time-consuming, and diffi cult to carry out, con-ducting real-world measurements and collecting measured channel data is a precondition for the successful validation of the results of preliminary theoretical efforts, and ascertains the benefi ts of employing multi-element antennas on satellite systems.

Motivated by this observation, this paper attempts to shed light on a variety of recent research activities with refer-ence to the characterization of the broadband satellite radio channel through measurement campaigns when multi-antennas are employed. After outlining the relevant background on MIMO satellite systems, this paper provides an overview of recent state-of-the-art multi-antenna land mobile satellite measurement campaigns, and the important milestones that have already been achieved. The review includes a presenta-tion of the measurement setup, and a brief critical description of the main results obtained from these measurements. Apart from considering the vehicular terminal case, the nomadic and pedestrian/handheld terminal cases are also examined, which invoke limited mobility and different antenna characteristics. A measurement campaign for the multi-antenna satellite-to-indoor channel is also included, where the propagation envi-ronment is more stringent than the typical land mobile satellite environment [66]. Since the Earth-space segment is not exclu-sively served by satellites [67, 68], this paper also discusses an indoor measurement campaign concerning a multi-antenna system based on high-altitude platforms (HAPs) [69], i.e., aircraft or airships fl ying in the stratosphere, capable of pro-viding wireless access over large coverage areas at low cost. The remainder of the paper is organized as follows. Sec-tion 2 briefl y discusses several MIMO techniques and their applications to the satellite domain. Section 3 presents various

Figure 1. A MIMO DVB-SH hybrid satellite-terrestrial network.



experimental approaches regarding multi-antenna satellite communications in outdoor propagation environments, and proceeds with the description of the measurement setup and the critical review of the corresponding results. Section 4 is targeted at the indoor multi-antenna satellite channels. Finally, Section 5 provides concluding remarks, and underlines future perspectives of MIMO technology for satellite networks.

2.ApplicationofMIMOTechnologytoSatellite Networks

The core idea behind MIMO technology is the use of either spatial multiplexing or space-time coding, where time is complemented with the spatial dimension inherent in the use of multiple spatially distributed antennas. However, the ter restrial and the satellite channels substantially differ, which makes the applicability of MIMO techniques to satellite sys tems a challenging subject [70]. The prerequisite so that single satellite confi gurations fully provide the spatial diversity and spatial multiplexing advantages predicted by information the ory is the existence of suffi cient antenna spacing, as well as a rich scattering environment, which renders the fading paths between the antenna elements of the transmitter/receiver inde pendent. Nevertheless, the huge distance between the satellite segment and the terrestrial stations reduces the corresponding radio link to an effective keyhole channel, with only one transmission path. The correlation among the MIMO sub-channels caused by a defi cient multipath environment then leads to a substantial loss in channel capacity from the ideal level predicted by MIMO theory [71]. Although previous studies suggested that single high-altitude platforms fl ying at altitudes of approximately 20 km above the ground can be employed to successfully exploit MIMO advantages [27, 72, 73], the deployment of multiple antennas at single satellites does not seem benefi cial, due to spatial limitations. It was shown in [27] that an antenna-element separation of at least 51.5 10× wavelengths is necessary to achieve low antenna correlation. The overwhelming majority of previous work related to multi-antenna satellite systems has thus focused on exploiting the following aspects of diversity [35], or a combi nation of them: (i) site diversity, where multiple cooperating and suffi -

ciently separated terrestrial stations communicate with a single satellite [74-76];

(ii) satellite diversity, also called angle or orbital diver-sity, through multiple suffi ciently separated satel-lites and a single terrestrial station equipped with multiple single polarization antennas [24, 25, 28, 29, 31, 35, 36, 38, 40, 42, 47, 53, 56, 64] or diver-sity through hybrid satellite-terrestrial MIMO sys-tems [65];

(iii) and polarization diversity, where a single dual-orthogonal polarized satellite communicates with a single terrestrial station equipped with a dual-orthogonal polarized antenna [3, 23, 26, 30, 32-34, 39, 41, 43, 46, 48-55, 58-60, 62, 63].

The interested reader is referred to [27, 72, 73, 77-79], where the application of multi-antenna technology to high-altitude platforms and the corresponding diversity issues are studied. Figures 2 and 3 demonstrate the principles of satellite and polarization diversity, respectively.

Polarization diversity represents a promising solution due to the recent advances in MIMO compact antennas [80], and intends to overcome possible space limitations and counter possible drawbacks of multiple satellite constellations, i.e., the waste of the limited satellite bandwidth for the transmission of the same signal, lack of synchronization in reception, sched-uling issues, inter-symbol interference, and high implementa-tion cost. Therefore, most previous research activities have been affi liated with the polarization domain. However, polari-zation diversity can only increase the throughput by a factor of two, whereas satellite diversity can result in an m-fold capac-ity increase, where m denotes the number of satellites. More-over, the on/off blockage phenomena and the highly correlated rainfall medium dominating at frequency bands well above 10 GHz may degrade the performance of polarization diversity [35]. It is worth noting that legacy terrestrial systems employ linear polarization, whereas satellite systems opt for circular polarization to overcome the effect of Faraday rotation in the ionosphere [81]. Other ionospheric and tropospheric effects are considered negligible at L and S frequency bands. There-fore, only the multipath propagation due to the local scattering near the terrestrial mobile stations is of great interest. Note that satellite and polarization diversity could be combined using multiple satellites, each utilizing a dual-polarization scheme. Space-polarization-time coding can then be exploited, and an extra increase in channel capacity is expected [53].

3. Measurements for Multi-Antenna Land Mobile Satellite Systems

In this section, the procedure and the setup of recently conducted measurement campaigns for multi-antenna satellite systems are described. The substantial results coming from these measurements are then reported and underlined.

3.1 Description of Measurement Campaigns

A land mobile satellite SIMO confi guration, using an S-band payload on the ARTEMIS geostationary Earth orbit (GEO) satellite, was evaluated in the framework of the ORTIGIA research project [37], co-funded by the European Space Agency (ESA). The scope of this project was to verify the techniques introduced by the DVB-SH standard to coun teract fading in satellite and terrestrial environments. The experiments were performed in rural, tree-shadowing, high way, suburban, and urban areas in Erlangen, Germany, and comprised satellite, terrestrial, and hybrid satellite-terrestrial architectures. The mobile reception unit included a van equipped with a directive and omnidirectional antennas. The follow up of the ORTIGIA project was the J-ORTIGIA project [44], which aimed at the

Figure 2. A simple representation of a land mobile satellite channel exploiting dual-satellite diversity.

Figure 3. A simple representation of a land mobile satellite channel exploiting polarization diversity.



experimental approaches regarding multi-antenna satellite communications in outdoor propagation environments, and proceeds with the description of the measurement setup and the critical review of the corresponding results. Section 4 is targeted at the indoor multi-antenna satellite channels. Finally, Section 5 provides concluding remarks, and underlines future perspectives of MIMO technology for satellite networks.

2.ApplicationofMIMOTechnologytoSatellite Networks

The core idea behind MIMO technology is the use of either spatial multiplexing or space-time coding, where time is complemented with the spatial dimension inherent in the use of multiple spatially distributed antennas. However, the ter restrial and the satellite channels substantially differ, which makes the applicability of MIMO techniques to satellite sys tems a challenging subject [70]. The prerequisite so that single satellite confi gurations fully provide the spatial diversity and spatial multiplexing advantages predicted by information the ory is the existence of suffi cient antenna spacing, as well as a rich scattering environment, which renders the fading paths between the antenna elements of the transmitter/receiver inde pendent. Nevertheless, the huge distance between the satellite segment and the terrestrial stations reduces the corresponding radio link to an effective keyhole channel, with only one transmission path. The correlation among the MIMO sub-channels caused by a defi cient multipath environment then leads to a substantial loss in channel capacity from the ideal level predicted by MIMO theory [71]. Although previous studies suggested that single high-altitude platforms fl ying at altitudes of approximately 20 km above the ground can be employed to successfully exploit MIMO advantages [27, 72, 73], the deployment of multiple antennas at single satellites does not seem benefi cial, due to spatial limitations. It was shown in [27] that an antenna-element separation of at least 51.5 10× wavelengths is necessary to achieve low antenna correlation. The overwhelming majority of previous work related to multi-antenna satellite systems has thus focused on exploiting the following aspects of diversity [35], or a combi nation of them: (i) site diversity, where multiple cooperating and suffi -

ciently separated terrestrial stations communicate with a single satellite [74-76];

(ii) satellite diversity, also called angle or orbital diver-sity, through multiple suffi ciently separated satel-lites and a single terrestrial station equipped with multiple single polarization antennas [24, 25, 28, 29, 31, 35, 36, 38, 40, 42, 47, 53, 56, 64] or diver-sity through hybrid satellite-terrestrial MIMO sys-tems [65];

(iii) and polarization diversity, where a single dual-orthogonal polarized satellite communicates with a single terrestrial station equipped with a dual-orthogonal polarized antenna [3, 23, 26, 30, 32-34, 39, 41, 43, 46, 48-55, 58-60, 62, 63].

The interested reader is referred to [27, 72, 73, 77-79], where the application of multi-antenna technology to high-altitude platforms and the corresponding diversity issues are studied. Figures 2 and 3 demonstrate the principles of satellite and polarization diversity, respectively.

Polarization diversity represents a promising solution due to the recent advances in MIMO compact antennas [80], and intends to overcome possible space limitations and counter possible drawbacks of multiple satellite constellations, i.e., the waste of the limited satellite bandwidth for the transmission of the same signal, lack of synchronization in reception, sched-uling issues, inter-symbol interference, and high implementa-tion cost. Therefore, most previous research activities have been affi liated with the polarization domain. However, polari-zation diversity can only increase the throughput by a factor of two, whereas satellite diversity can result in an m-fold capac-ity increase, where m denotes the number of satellites. More-over, the on/off blockage phenomena and the highly correlated rainfall medium dominating at frequency bands well above 10 GHz may degrade the performance of polarization diversity [35]. It is worth noting that legacy terrestrial systems employ linear polarization, whereas satellite systems opt for circular polarization to overcome the effect of Faraday rotation in the ionosphere [81]. Other ionospheric and tropospheric effects are considered negligible at L and S frequency bands. There-fore, only the multipath propagation due to the local scattering near the terrestrial mobile stations is of great interest. Note that satellite and polarization diversity could be combined using multiple satellites, each utilizing a dual-polarization scheme. Space-polarization-time coding can then be exploited, and an extra increase in channel capacity is expected [53].

3. Measurements for Multi-Antenna Land Mobile Satellite Systems

In this section, the procedure and the setup of recently conducted measurement campaigns for multi-antenna satellite systems are described. The substantial results coming from these measurements are then reported and underlined.


A land mobile satellite SIMO confi guration, using an S-band payload on the ARTEMIS geostationary Earth orbit (GEO) satellite, was evaluated in the framework of the ORTIGIA research project [37], co-funded by the European Space Agency (ESA). The scope of this project was to verify the techniques introduced by the DVB-SH standard to coun teract fading in satellite and terrestrial environments. The experiments were performed in rural, tree-shadowing, high way, suburban, and urban areas in Erlangen, Germany, and comprised satellite, terrestrial, and hybrid satellite-terrestrial architectures. The mobile reception unit included a van equipped with a directive and omnidirectional antennas. The follow up of the ORTIGIA project was the J-ORTIGIA project [44], which aimed at the

Figure 2. A simple representation of a land mobile satellite channel exploiting dual-satellite diversity.

Figure 3. A simple representation of a land mobile satellite channel exploiting polarization diversity.



performance optimization of the DVB-SH standard in hybrid satellite-terrestrial networks. It performed on-fi eld trials using the satellite S-band payload on the W2A satellite in urban, suburban, highway, and rural envi ronments in Pisa, Italy. A DVB-SH receiver developed by the Fraunhofer IIS was used, and allowed for antenna diversity with up to four antennas.

In [51], measurements of the antenna diversity gain for various antenna confi gurations using a high-power satellite (ICO-G1) acting as a transmitter were conducted along the east coast of the US, considering a 2.185 GHz carrier fre-quency (S band) and various environments, i.e., highways, rural, suburban, urban areas, and areas with trees. The receiver was a van equipped with four antennas, placed front, back, left, and right on the rooftop of the vehicle. The Fraunhofer IIS channel measurement equipment (CME) was used to record in parallel the signals from each antenna. Moreover, a Global Positioning System (GPS) receiver logged details related to the exact measurement time and the vehicle’s posi tion, while a front camera behind the windscreen and a fi sheye camera on the van’s rooftop captured the environmental char acteristics.

In [40], two satellites in geostationary orbit with 30° sepa ration were used in urban, residential, and rural environ-ments, and results for fade correlation in time and space were presented. The measurements were performed in the US using two operational XM satellites in the 2,332.5 MHz to 2,345 MHz band, with a bandwidth of 1.5 MHz and an active quadrifi lar helix left-hand circular polarized (LHCP) antenna. The lengths of the measurement trials were 2,300 m, 4,300 m, and 4,600 m for the urban, the residential, and the rural areas, respectively.

In [56, 64], on-fi eld propagation experiments were car-ried out by ESA in the frame of the Mobile satellite channeL with Angle DiversitY (MiLADY) project by exploiting the availability of existing satellite constellations. Two measure-ment campaigns were conducted. The fi rst one was along the east coast of the US, using two XM GEO satellites and three Sirius highly-elliptical-orbit (HEO) satellites for satellite digital audio radio services (SDARS) at S band. The second campaign was around Erlangen in Germany, using 20 GPS or GLONASS medium Earth orbit (MEO) satellites for global navigation satellite systems (GNSS) for a high variability of angle diversity constellations and different propagation envi-ronments. The measured data were analyzed in terms of the satellites’ elevation angles (varying between 10° and 90°) and azimuth separations (from 0° to 180° in segments of 10°). In the fi rst experiment, the signals were sampled with a high sampling rate (2.1 kHz) in urban, suburban, tree-shadowed, forest, commercial, and highway (open) environments. In the second experiment, the permanent availability of at least eight satellites on the hemisphere enabled the comprehensive analy-sis of slow fading correlation for a wide range of elevation and azimuth angle combinations of multiple-satellite constella tions. The GNSS campaign was divided in two parts. In the fi rst part, the GNSS antenna was mounted on a van at a height of 2 m. A round-trip measurement of 38 km length was driven ten times, covering several environments, i.e., suburban, for est, open, commercial, in and around Erlangen. In the second part, the

GNSS antenna was mounted at a height of 3.1 m onto two city buses, driving on different routes.

The potential MIMO channel capacity of a land mobile dual-satellite system was experimentally investigated in [31], where a measurement campaign was carried out in Guildford, UK. Two adjacently positioned low-elevation (mean elevation angle 15°) geostationary satellites, operating at 2.45 GHz car-rier frequency with 200 MHz bandwidth, were emulated using a hilltop, each with a right-hand-circular polarized (RHCP) antenna. A dual-antenna vehicle containing two RHCP anten-nas was also used in main road, suburban, and urban environ-ments.

By exploiting spatial and circular polarization diversity techniques, experimental propagation results for the land mobile satellite MISO and SIMO channels at S band (2.2 GHz) and 100 kHz bandwidth were presented in [43]. The experiment was performed in the small French city named Auch, using a channel sounder developed by Centre National d’Etudes Spatiales (CNES) for multi-link simultaneous meas urements. A helicopter equipped with two collocated trans mitters was employed to emulate a GEO satellite at a 35° ele vation angle (fl ying at about 2,600 m above the ground). The fi rst transmitter was connected to a RHCP antenna and the second one to a LHCP antenna. The receiving antennas were two identical vertically polarized (V-polarized) dipoles, spa tially separated by a distance of 11.5 cm, which supported the simultaneous measurements of both the land mobile satellite and terrestrial channels. These antennas were located on a mast at the rear of the measurement van. The measurement data were collected in different propagation environments: a tree-lined road with quite dense vegetation, a suburban area with relatively spaced buildings, a high density built-up urban area, and a continuous combination of all these environments.

Since dual-circular-polarization MIMO confi gurations were not addressed by the experiment in [43], an extra experiment concerning MIMO and SIMO architectures was carried out by the French Aerospace Lab ONERA and CNES to characterize both GEO land mobile satellite and nomadic satellite channels at 2.2 GHz and 3.8 GHz [60]. The term “nomadic” refers to the non-stationary characteristics of the environment close to the receiver. To emulate the GEO satel-lite, two terrestrial transmitters were situated on a mountain surrounding Saint Lary village, France, and elevation angles between 20° and 30° were maintained. The transmitter was equipped with two RHCP and LHCP patch antennas, while the receiver was located on the van rooftop and equipped with two types of antennas, a dual-polarized (RHCP and LHCP) antenna (2.2 GHz and 3.8 GHz) and two V-polarized dipoles.

As far as polarization diversity was exploited, the meas-urement campaign conducted in the frame of [32, 33] was the fi rst to investigate the wideband characteristics of land mobile satellite MIMO systems equipped with dual-orthogonal polarized antennas. Specifi cally, a single low-elevation (5°-18°) dual-circularly polarized radio channel was emulated in Guildford, UK, and tree-lined road, suburban, and urban envi-

ronments were considered. An Elektrobit Propsound wideband MIMO channel sounder confi gured for a 2.45 GHz carrier frequency and 200 MHz bandwidth was used. This sounder system was based on an exceptionally fast data acquisition and storage concept, providing real-time assessment of virtually any channel data during the ongoing channel measurement in the fi eld. The properties of radio channels can be measured by using pulse sounding, frequency-sweep techniques or correla-tion methods. Both the transmitter and receiver were con trolled through a personal computer and were capable of con trolling RF switches, which were synchronized in order to make time-multiplexed MIMO measurements. To emulate a downlink satellite scenario, the transmitter was a terrestrially based artifi cial platform on a hilltop containing directional RHCP and LHCP antennas, whereas the receiver was a van employing omnidirectional RHCP and LHCP antennas. The scattering created some depolarization from RHCP to LHCP and from LHCP to RHCP, which were represented in a 2 × 2 polarized MIMO channel matrix. Figure 4 shows these four channels, where the subscripts R and L denote the RHCP and LHCP antennas at each end of the link, and Rn and Ln repre sent the additive white Gaussian noise (AWGN) at each antenna. A similar measurement setup was also realized in [49, 58]. However, in [49], the receiver terminal employed two RHCP and LHCP reference antennas and one dual circu larly polarized contra-wound quadrifi lar helix antenna (CQHA) with opposite winding direction to radiate orthogonal circular polarization.

To accommodate higher elevation angles than those observed in [32, 33, 49, 58], two measurement campaigns were carried out in [54]. In the fi rst measurement campaign, the satellite was emulated by mast-mounted directional RHCP and LHCP antennas placed on a hill. The vehicular mobile receiver used omnidirectional RHCP and LHCP antennas mounted on the roof of a vehicle driven along pre-selected routes in a rural environment. The second measurement cam paign was conducted in a suburban area for a 2.5 GHz carrier frequency and 15°-37° elevation angles. To emulate the satel lite, a mast mounting two RHCP and LHCP directional anten nas was installed on a tower block.

During the MIMOSA project funded by ESA, measure-ment campaigns at 2.187 GHz carrier frequency and 5 MHz bandwidth were conducted to statistically analyze a dual-polarized 2 × 2 MIMO channel from a single Eutelsat W2A satellite acting as the transmitter, while the receiving antennas were installed on a car roof [50]. Both the transmitter and the receiver were equipped with LHCP and RHCP antennas, and different propagation environments were measured, i.e., urban, suburban, rural highway, and forest.

Figure 5 illustrates several types of satellite transmitter emulation, while Table 1 summarizes the aforementioned measurement campaigns.

Figure 5. Three types of emulation of the satellite transmit-ter for a rural tree-lined road propagation environment.

Figure 4. The outline of the dual-polarized MIMO channel model.



Table 1. A summary of measurement campaigns for multi-antenna satellite systems.

Ref. Location Environment Satellite Emulation

Multi-AntennaSystem

Carrier Frequency

(GHz)Bandwidth Elevation

Angle

[31] Guildford, UK

Main road, suburban, and urban

Artifi cial platform on a hilltop

Dual-Satellite MIMO 2.45 200 MHz ~15°

[32, 33] Guildford, UK

Urban, Suburban and tree-lined road


Single-Satellite Dual-Polarized MIMO

2.45 200 MHz 5°-18°

[37] Erlangen, Germany

Rural, tree-shadowing, highway, sub-urban, and urban

ARTEMIS GEO satellite SIMO 1-3 1.5 MHz –

[40] US Urban, residential, rural

Two real XM-Radio Satellites

Dual-satellite MISO

2.332-2.345 1.5 MHz 28°-44°

[43] Auch, France

Tree-lined road, suburban, high density built-up urban area

Helicopter equipped with two collocated transmitters

Single-Satellite Dual-Polarized MISO and SIMO

2.2 100 kHz 35°

[44] Pisa, ItalyUrban, sub-urban, highway, and rural

Real Eutelsat W2A Satellite SIMO 2.170-

2.200 4.75 MHz –

[49] Guildford, UK

Hilly rural area with tree-lined roads



2.43 50 MHz 10°


Urban, suburban, rural highway, and forest

Real Eutelsat W2A Satellite


2.187 5 MHz 30°-40°

[51] US, East Cost

Highways, rural, suburban, urban areas, and areas with trees

Real ICO-G1 Satellite SIMO 2.185

Up to 34.67 MHz*;

up to 52 MHz**

29°-46°

[54] Guildford, UK

Rural and suburban

Mast placed on (a) a hill and (b) a tower block


2.5 200 MHz 15°-37°

[56, 64]

US East Cost and Erlangen, Germany

Urban, sub-urban, tree-shadowed, forest, commercial, and highway (open)

Real SDARS satellites and GNSS

Dual-satellite MISO

2.3 (US East Cost)

1.575 (Erlangen, Germany)

10°-90°

[58] Guildford, UK Tree-lined road



2.45 200 MHz 7°-18°

[60] Saint Lary, France

Rural, built-up areas, tree alleys, and open areas

Two transmitters on a mountain

Single-Satellite Dual-Polarized MIMO and SIMO

2.2 and 3.8 CW 20°-30°

[66, 69]Graz and Vienna, Austria

Indoor Helicopter SIMO S-band 200 MHz 15°-60°

* single-antenna; ** multi-antenna

3.2 Description and Critical Review of the ExperimentalResults

In [31, 32], the channel-capacity improvement of a dual-satellite single-polarized (DS-SP) land mobile satellite MIMO system and a single-satellite dual-polarized (SS-DP) land mobile satellite MIMO system over a single-satellite single-polarized (SS-SP) land mobile satellite SISO system were presented. The available channel capacity was estimated for a received single-to-noise ratio (SNR) of 15 dB. The main results are illustrated in Table 2 and Figure 6. It was obvious that the single-satellite dual-polarized and dual-satellite single-polarized MIMO systems signifi cantly outperformed the sin-gle-satellite single-polarized SISO system in terms of the out-age capacity. These results also depicted that the single-satel lite dual-polarized system performed better than the dual-sat ellite single-polarized system. They suggested that using dual-polarization is more benefi cial than implementing two distinct transmitters. An interesting result raised from these specifi c measurements is that the achieved capacity was smaller in urban areas, probably due to the increased strength of the line-of-sight (LoS) component and the corresponding spatial cor relation introduced. The channel capacities for several con fi gurations (2.2 GHz, 3.8 GHz, SISO, SIMO, and single-satel lite dual-polarized MIMO) were also investigated in [60]. The capacity results showed that the MIMO confi guration outper formed the SISO, as expected. However, for low outage prob abilities (less than 15%), the SIMO system performs evenly well. In [49], the channel capacity of the contra-wound quadri-fi lar helix antenna was evaluated and compared with that of spatially separated reference antennas. The experimental results depicted that the contra-wound quadrifi lar helix antenna has nearly the same capacity performance as the ref erence antennas in non-line-of-sight (NLoS) environments. In obstructed line-of-sight (OLoS) areas with Ricean K-factor equal to approximately 5 dB, suitable orientation of the con tra-wound quadrifi lar helix antenna is required. In addition, the collocated contra-wound quadrifi lar helix antenna gives lower correlation than the reference antenna in obstructed line-of-sight areas, while the correlation reduces with decreasing Ricean K-factor in all scenarios. Results for the 50% outage SISO and MIMO channel capacity and for 20 dB SNR are shown in Table 3.

The effects of channel correlation on the capacity of a single-satellite dual-polarized land mobile satellite MIMO channel were investigated in [54]. Specifi cally, the capacity for dual circular polarization multiplexing (DCPM) was com pared with the theoretical capacity of an equal-power-alloca tion MIMO system. The results showed that at high correla tion (co-

Table 2. The 50% outage capacity of single-satellite single-polarized SISO, single-satellite dual-polarized

MIMO, and dual-satellite single-polarized land mobile satellite MIMO channels for different propagation

environments and 15 dB SNR.

SNR = 15 dB

50% Outage Capacity (bps/Hz)SS-DP DS-SP

SISO MIMO SISO MIMORoad 0.39 0.96 0.62 1.13Suburban 0.8 1.35 0.44 0.84Urban 0.27 0.6 0.33 0.63

Table 3. The 50% outage capacity of land mobile satellite SISO and land mobile satellite MIMO channels using a contrawound quadrifi lar helix antenna for obstructed

line-of-sight and non-line-of-sight scenariosand 20 dB SNR.

SNR = 20 dB50% Outage Capacity (bps/Hz)

OLoS NLoSSISO 5.5-6.5 6MIMO 8-11 9.5-10.5

Figure 6. The 10% outage MIMO capacity of single-satel-lite dual-polarized and dual-satellite single-polarized land mobile satellite MIMO channels in bps/Hz for different propagation environments and 15 dB SNR.



Table 1. A summary of measurement campaigns for multi-antenna satellite systems.

Ref. Location Environment Satellite Emulation

Multi-AntennaSystem

Carrier Frequency

(GHz)Bandwidth Elevation

Angle

[31] Guildford, UK

Main road, suburban, and urban


Dual-Satellite MIMO 2.45 200 MHz ~15°

[32, 33] Guildford, UK

Urban, Suburban and tree-lined road



2.45 200 MHz 5°-18°


Rural, tree-shadowing, highway, sub-urban, and urban

ARTEMIS GEO satellite SIMO 1-3 1.5 MHz –

[40] US Urban, residential, rural

Two real XM-Radio Satellites

Dual-satellite MISO

2.332-2.345 1.5 MHz 28°-44°

[43] Auch, France

Tree-lined road, suburban, high density built-up urban area

Helicopter equipped with two collocated transmitters

Single-Satellite Dual-Polarized MISO and SIMO

2.2 100 kHz 35°

[44] Pisa, ItalyUrban, sub-urban, highway, and rural

Real Eutelsat W2A Satellite SIMO 2.170-

2.200 4.75 MHz –

[49] Guildford, UK

Hilly rural area with tree-lined roads



2.43 50 MHz 10°


Urban, suburban, rural highway, and forest

Real Eutelsat W2A Satellite


2.187 5 MHz 30°-40°

[51] US, East Cost

Highways, rural, suburban, urban areas, and areas with trees

Real ICO-G1 Satellite SIMO 2.185

Up to 34.67 MHz*;

up to 52 MHz**

29°-46°

[54] Guildford, UK

Rural and suburban

Mast placed on (a) a hill and (b) a tower block


2.5 200 MHz 15°-37°

[56, 64]

US East Cost and Erlangen, Germany

Urban, sub-urban, tree-shadowed, forest, commercial, and highway (open)

Real SDARS satellites and GNSS

Dual-satellite MISO

2.3 (US East Cost)

1.575 (Erlangen, Germany)

10°-90°

[58] Guildford, UK Tree-lined road



2.45 200 MHz 7°-18°

[60] Saint Lary, France

Rural, built-up areas, tree alleys, and open areas

Two transmitters on a mountain

Single-Satellite Dual-Polarized MIMO and SIMO

2.2 and 3.8 CW 20°-30°

[66, 69]Graz and Vienna, Austria

Indoor Helicopter SIMO S-band 200 MHz 15°-60°

* single-antenna; ** multi-antenna


In [31, 32], the channel-capacity improvement of a dual-satellite single-polarized (DS-SP) land mobile satellite MIMO system and a single-satellite dual-polarized (SS-DP) land mobile satellite MIMO system over a single-satellite single-polarized (SS-SP) land mobile satellite SISO system were presented. The available channel capacity was estimated for a received single-to-noise ratio (SNR) of 15 dB. The main results are illustrated in Table 2 and Figure 6. It was obvious that the single-satellite dual-polarized and dual-satellite single-polarized MIMO systems signifi cantly outperformed the sin-gle-satellite single-polarized SISO system in terms of the out-age capacity. These results also depicted that the single-satel lite dual-polarized system performed better than the dual-sat ellite single-polarized system. They suggested that using dual-polarization is more benefi cial than implementing two distinct transmitters. An interesting result raised from these specifi c measurements is that the achieved capacity was smaller in urban areas, probably due to the increased strength of the line-of-sight (LoS) component and the corresponding spatial cor relation introduced. The channel capacities for several con fi gurations (2.2 GHz, 3.8 GHz, SISO, SIMO, and single-satel lite dual-polarized MIMO) were also investigated in [60]. The capacity results showed that the MIMO confi guration outper formed the SISO, as expected. However, for low outage prob abilities (less than 15%), the SIMO system performs evenly well. In [49], the channel capacity of the contra-wound quadri-fi lar helix antenna was evaluated and compared with that of spatially separated reference antennas. The experimental results depicted that the contra-wound quadrifi lar helix antenna has nearly the same capacity performance as the ref erence antennas in non-line-of-sight (NLoS) environments. In obstructed line-of-sight (OLoS) areas with Ricean K-factor equal to approximately 5 dB, suitable orientation of the con tra-wound quadrifi lar helix antenna is required. In addition, the collocated contra-wound quadrifi lar helix antenna gives lower correlation than the reference antenna in obstructed line-of-sight areas, while the correlation reduces with decreasing Ricean K-factor in all scenarios. Results for the 50% outage SISO and MIMO channel capacity and for 20 dB SNR are shown in Table 3.

The effects of channel correlation on the capacity of a single-satellite dual-polarized land mobile satellite MIMO channel were investigated in [54]. Specifi cally, the capacity for dual circular polarization multiplexing (DCPM) was com pared with the theoretical capacity of an equal-power-alloca tion MIMO system. The results showed that at high correla tion (co-

Table 2. The 50% outage capacity of single-satellite single-polarized SISO, single-satellite dual-polarized

MIMO, and dual-satellite single-polarized land mobile satellite MIMO channels for different propagation

environments and 15 dB SNR.

SNR = 15 dB

50% Outage Capacity (bps/Hz)SS-DP DS-SP

SISO MIMO SISO MIMORoad 0.39 0.96 0.62 1.13Suburban 0.8 1.35 0.44 0.84Urban 0.27 0.6 0.33 0.63

Table 3. The 50% outage capacity of land mobile satellite SISO and land mobile satellite MIMO channels using a contrawound quadrifi lar helix antenna for obstructed

line-of-sight and non-line-of-sight scenariosand 20 dB SNR.

SNR = 20 dB50% Outage Capacity (bps/Hz)

OLoS NLoSSISO 5.5-6.5 6MIMO 8-11 9.5-10.5

Figure 6. The 10% outage MIMO capacity of single-satel-lite dual-polarized and dual-satellite single-polarized land mobile satellite MIMO channels in bps/Hz for different propagation environments and 15 dB SNR.



polar 0.95 and cross-polar 0.7) and with SNR values less than 10 dB, dual circular polarization multiplexing pro vides slightly better channel capacity than equal-power-allo cation MIMO. However, at SNR values above 12 dB, tradi tional MIMO gives better performance, while lower channel correlation (co-polar 0.5 and cross-polar 0.3) negatively infl u ences the capacity of dual circular polarization multiplexing but has an insignifi cant impact on the capacity of equal-power-allocation MIMO. Dual circular polarization multi plexing therefore does not succeed with reducing channel cor relation, whereas low receiver SNRs in highly correlated MIMO channels ensure the satisfactory performance of dual circular polarization multiplexing.

In the fi rst measurement campaign of the MIMOSA pro-ject [50], both the overall statistics of the MIMO channel and the large-scale fading-channel states (good/bad states) were experimentally investigated and analyzed. The results showed that the correlation for the dual-polarized antenna pair was higher than the correlation of the two single-polarized anten nas. The relationship between the co-polarized signal and the cross-polarized sub-channel for different environments was also shown. Specifi cally, for suburban environments, the cross-polarized signal may be even stronger than the co-polarized signal. In addition, the strengths of the direct com ponent (line-of-sight) and multipath component (non-line-of-sight) were also estimated. The Rice factor varied from 0 dB to 20 dB for tree shadowing, whereas values between 10− dB and 5 dB where observed for the cross-polarized signal.

The depolarization of the received signal due to the chan-nel conditions was also studied in [49]. The cross-polarization discrimination (XPD) in the non-line-of-sight and obstructed line-of-sight areas – which is defi ned as the ratio of co-polar-ized average received power to the cross-polarized average received power – was the key parameter. The results showed that increasing the density of trees along the measurement road in the non-line-of-sight area increased channel depolari-zation. The results in [60] indicated that the S-band antennas’ cross-polarization discrimination was higher than the C-band cross-polarization discrimination. Multipath power statistics to characterize the infl uence of antenna types (RHCP, LHCP, or V-polarized dipole) and frequency band were also estimated. A slight difference (lower than 1 dB) existed between 2.2 GHz and 3.8 GHz dual-polarized antennas. The major difference

(higher than 1 dB) in terms of multipath power was between circular polarized and dipole antennas.

The correlation matrix for large-scale fading was initially constructed based on the measurement data in [58] in a typical tree-lined road of a suburban environment. Moreover, the standard deviation and mean values of shadowing were derived from the measured data. The measurements also pro vided data concerning the Rice K-factor, for which values ranging from 0 to 10 for co-polar data were observed. The results depicted that a high Rice K-factor corresponded to an inherently high co-polar correlation and high cross-polariza tion discrimination (15 dB), while a low Rice K-factor led to low correlation with greater variance and cross-polarization discrimination close to 0 dB.

In [33], the measured raw data extracted from the wide-band MIMO channel sounder was properly normalized with respect to the free space loss (FSL) and delay at each distance between the emulated satellite and the vehicle. The wideband fading characteristics were then studied. Results for the fi rst delay bin for co-/cross-polarized channels were gathered and displayed in Table 4. In addition, the results concerning the coherence time showed that the median normalized coherence time dfτ , where df is the maximum Doppler frequency, for co-polarized tree-lined road channels was 0.86 at 0 ns, decreasing to 0.44 at 10 ns, 0.28 at 20 ns, and 0.18 at 30 ns. The coherence time hence decreased with increasing delay. However, higher excess delays had similar coherence times to the 30 ns delay point. The delay domain fading correlation coeffi cients were also obtained between each pair of bins in the delay domain. It was shown that increased delay separa tions had a lower correlation coeffi cient, due to the longer and different shadowing path. Moderate correlations were found in the fi rst delay bin for the tree-lined road and suburban envi-ronments, while no signifi cant correlation was found in the fi rst delay bin for the urban environment. The direct-path cor relation coeffi cients for co-/cross-polarized channels and the root mean squared (rms) delay spread of the impulse response are also presented in Table 4. Since the small-scale correlation between MIMO channels directly controls the performance of MIMO systems, an investigation of the correlation between MIMO channels in the land mobile satellite dual polarization system was also obtained, and showed that the correlation decreased

Table 4. The coherence distance for the fi rst delay bin, rms delay spread, and correlation coeffi cient for different propagation environments.

PropagationEnvironment

Coherence Distance (1st Delay Bin in

Meters)

rms Delay Spread (ns)

Correlation Coeffi cient

co- cross- co- cross- co- cross-Tree-lined road 29 31 54 58 0.62 0.72Suburban 132 160 29 44 0.38 0.42Urban 204 291 63 58 – –

with increasing excess delays. In addition, identi cally located scatterers, i.e., non-isotropic scattering, caused high correlation, while separately located scatterers, i.e., iso tropic scattering, led to low correlation. Similar results for the high-altitude platform-MIMO channel were also obtained in [72].

The large-scale fading correlation coeffi cient between land mobile satellite MIMO narrowband channels in the com bined spatial/polarization domain was also estimated in [82]. The results in Table 5 confi rmed that strong correlation existed (close to 1) between each pair of these channels for all propagation environments examined. These values were expected, since both antennas were co-located at one satellite and likewise co-located at one vehicle. The results in [82] also indicated that the correlation coeffi cients became similarly high values in the case of higher elevation angles. Further experimental results or accurate simulations using ray-tracing models are required in other areas with different propagation conditions in order to investigate the dependence of the corre-lation values on the specifi c sites. These average large-scale correlation coeffi cient matrices have already been used for the evaluation of MIMO satellite scenarios by the European Space Agency [46, 48, 62, 83].

Fade measurement results for the space-time correlation of signals from two satellites in geostationary orbit were pre sented in [40]. Several network confi gurations were used, i.e., single-satellite space diversity, two-satellite space diversity (each with continuous interleaver), single-satellite time diver sity and two-satellite space and time diversity (each with dis crete delay and short interleaver). The results for single-satel lite showed that the coherence distance was around 4 m in the rural area, 7 m in

the residential area, and up to 18 m in the urban area due to the local blockage variation introduced by the buildings. Moreover, the correlation coeffi cient of dual satellite fades was suffi ciently small and below 0.3 for the rural and residential areas, whereas the correlation reached values of up to 0.7 in the urban area. For short interleavers (slowly moving receivers) of 5 m, the diversity gain was 2.3 dB for two-satellite space diversity in the residential area, 0.3 dB for one-satellite time diversity, and 4.1 dB for two-sat ellite space and time diversity. However, the gain was below 1 dB in the rural area for all network confi gurations. For long interleavers of 100 m in the residential area, a diversity gain of 0.5 dB could be obtained only for the two-satellite space-diversity confi guration. Overall, the single-satellite time diver sity confi guration based on continuous random interleaving signifi cantly increased availability, whereas a single-satellite with discrete-time diversity and short interleaving was less effective. In addition, the two-satellite space-diversity con fi guration satisfactorily performed for short interleavers, while using space diversity in combination with discrete-time diver sity and short interleaving had the same performance as the space diversity with long interleavers.

In [43], SIMO and MISO measurements of the land mobile satellite channel at S band were conducted, and the fading margin as a function of coverage was studied. The results underlined that using diversity techniques reduces the fading margin for a given target coverage (better than 90%) for high-availability systems. However, for coverage less than 80%, diversity techniques are not effective due to the high values of the Rice K-factor usually observed in suburban areas. In addition, exploiting spatial diversity at the receiver side may be more effi cacious than using polarization diversity for high-availability land mobile satellite systems. Specifi cally, possible maximum ratio combining (MRC) gains from 4 dB up to 8 dB can be achieved depending on the target cov erage in a mixed environment. Nevertheless, combining cir cular polarization diversity with spatial diversity leads to a slight reduction in the fading margin.

In [51], results of the achievable antenna diversity gain for various antenna confi gurations in different environments were presented. The performance evaluation was based on the estimation of the word error rate (WER) for ETSI Satellite Digital Radio (ETSI SDR). The actual channel capacity was primarily estimated from the measured data, and the word error rates were derived depending on the physical layer con-fi guration. The results depicted the required carrier-to-noise ratio (C/N) for the line-of-sight case for achieving a target word error rate of 5% for single- and multi-antenna reception using selection combining (SC) and maximum-ratio combin-ing in six different environments. Figure 7 demonstrates the required C/N for a 5% word error rate for single-antenna reception and four antennas using maximum-ratio combining in several propagation environments. One observed that the required C/N highly depends on the probability of obstacles in the environment. Note that urban areas demand high C/N val-ues, which in turn might require the installation of terrestrial repeaters to ensure adequate quality of service. Although the required C/N for a certain word error rate strongly depends on the environment, the corresponding antenna diversity gain of

Table 5. The average largescale correlation coeffi cients between land mobile satellite MIMO channels for different

propagation environments [82].

Large-Scale Fading

Correlation Coeffi cientsR/R L/L R/L L/R R/R

Urban

R/R 1.00

L/L 0.86 1.00

R/L 0.86 0.89 1.00

L/R 0.92 0.85 0.93 1.00

Suburban

R/R 1.00

L/L 0.76 1.00

R/L 0.76 0.83 1.00

L/R 0.83 0.75 0.78 1.00

Main Road

R/R 1.00

L/L 0.86 1.00

R/L 0.85 0.91 1.00

L/R 0.90 0.87 0.88 1.00



each antenna confi guration is independent from the environ-ment. In all measurement results, the maximum-ratio com-bining (providing a power combining gain, a fading reduction gain, and a gain due to an improved overall antenna pattern) performed better than the selection combining (providing no power combining gain).

In [64], results of the GNSS and SDARS systems were presented in terms of state probabilities and state duration sta-tistics for different environments and orbital positions of the satellites for both single- and dual-satellite reception. Consid-ering the single-satellite case, the results showed that the “bad”-state probability [14, 84], which corresponds to heavy shadowing/blockage, increased with increasing the angle between satellite azimuth and driving direction from 0° to 90°. However, the “bad”-state probability decreased with increas-ing satellite elevation, and for elevation angles larger than 70°, the infl uence of the driving direction was insignifi cant. More-over, the “bad”-state probability in urban and forest areas was generally higher than in other environments. In addition, the SDARS and GNSS measurements extracted similar results for urban areas, whereas lower signal availability was obtained for SDARS in suburban, forest, commercial, and open areas. For the dual-satellite case, results concerning the correlation coef fi cient between the states of two satellites as a function of the azimuth separation derived from the measurements were depicted. Considering small azimuth separations, both state sequences were highly correlated. However, the correlation was minimized for azimuth separations between 60° and 120° and slightly increased towards 180° azimuth separation. The correlation coeffi cient also depends on the elevation angle separation between two satellites.

In [37], the service availability of the satellite component of DVB-SH in S band in several propagation environments was experimentally investigated. The results showed that the availability is extremely high (almost always 100%) in high-way and rural environments with affordable satellite equiva-lent isotropically radiated power (EIRP). In light tree shad-owed and suburban areas, the service availability is still rather high. However, in urban, dense-urban, and indoor scenarios, the quality of the service is degraded, and the deployment of a

terrestrial repeater is necessary. The hybrid confi guration then leads to service availabilities of the order of 90%. The per-formance enhancement obtained using hybrid reception in areas where neither the satellite nor the terrestrial segment allows for unexceptionable reception was also demonstrated in [44]. The results depicted that the service availability is over 90%.

The measurements in [54, 58, 64, 66] have resulted in channel models that can be used as a cost-effective and time-saving approach for the test, optimization, and performance evaluation of multi-antenna land mobile satellite systems. Specifi cally, a simple stochastic channel model was generated and validated in [54] by exploiting dual circular polarization multiplexing, under line-of-sight and obstructed line-of-sight fading conditions. In [58], an empirical-stochastic dual circu-lar polarized land mobile satellite-MIMO narrowband channel model, based on Markov states, was implemented and vali-dated at low elevation angles. Different approaches for dual-satellite state narrowband channel modeling based on experi-mental data were presented in [64]. In addition, an empirical-statistical model for the satellite-to-indoor propagation chan nel was derived from measurements in [66], and can be used for system simulation. Nevertheless, all the above presented results were site-, scenario-, channel sounder equipment-, antenna-, and frequency-dependent. Further measurement campaigns with mu lti-antenna elements and new technology equipment should therefore be designed and are required in order to unify them into a MIMO satellite radio channel within International Telecommunication Union-Radio Sector. Another important issue is to take advantage of the MIMO land mobile satellite real-world measurements in order to develop step-by-step methodologies for the simulation and time-series generation of MIMO land mobile satellite channel models [46]. Geometrical-stochastic WINNER-like models can also be developed to characterize diverse satellite commu nication environments/scenarios. These models require statis tical channel parameters described by statistical distributions extracted from extensive MIMO channel measurements. These parameters include temporal and spatial, e.g., multipath azi muth/elevation angles of arrival/departure information obtained by the analysis and processing of the measured data.

4. Measurements for Multi-Antenna Satellite-to-Indoor Systems

Although broadcasting and navigation (GNSS from L to C band [85]) services have originally been developed for the coverage of extended outdoor areas, the provision of these services in indoor environments has recently gained increasing importance in research and industry [86]. Nevertheless, the satellite-to-indoor channel poses important challenges due to severe signal degradation. As illustrated in Figure 8, the satel-lite-to-indoor channel is not only a function of the ionospheric, tropospheric, and multipath effects, but also strongly depends on the building type and structure, the layout of rooms, and the type of construction materials used. In addition, the position of the receiver inside the building and the elevation of the trans-mitter also make it diffi cult to accurately estimate the level of

Figure 7. The required C/N in dB for a 5% word error rate using one or four antennas in several propagation environments.

received power inside a building. Additional processing gain and increased link margins are therefore required in order to preserve a nominal signal level and improve the signal detec-tion. For these measures, several techniques including high-sensitivity GPS (HSGPS), assisted GPS (AGPS), and diversity techniques have been utilized. Time diversity has been tradi-tionally exploited using long interleavers to overcome fading losses. In addition, exploiting spatial diversity though ade-quately separated multiple antennas enables the reception of multiple independent signal samples, which in turns leads to both array and diversity gain, increased average received sig-nal power, and decreased signal fading margins [87, 88]. The spatial diversity performance of different antenna confi gura-tions in a satellite-to-indoor channel was estimated in [89]. By using polarization diversity, the stationary or portable recep tion in indoor environments can also be enhanced [90]. Based on three-dimensional (3-D) ray-tracing simulations, the results in [91] revealed that the polarization state of the propagation wave in indoor environments signifi cantly changes.

Since performing channel-sounder measurements is a proven method to gain knowledge about a specifi c propaga-tion channel, various channel-measurement campaigns in dif-ferent environments should be carried out regarding the area of broadband satellite-to-indoor wave propagation. However, work on the characterization of multi-antenna satellite-to-indoor channels through measurements is scarce in the litera-ture. This section describes these measurement efforts, and

the corresponding results along with a measurement campaign based on high-altitude platforms providing indoor communi-cation services.


The multi-antenna satellite-to-indoor communication channel was initially characterized in [66], and a hybrid empirical-statistical model for the satellite-to-indoor propaga-tion channel at S band was proposed. Specifi cally, a wideband circularly polarized (RHCP) directive channel sounder in a SIMO confi guration was placed inside several buildings in Graz and Vienna, Austria. It received signals from a transmit ter carried by a helicopter to simulate the satellite, which remained quasi-stationary for each measurement. The receiv ing antenna system was located in a building. It consisted of a multiple patch antenna with two orthogonal linear polariza tions ( 45± ° ) and both co-polar (RHCP) and cross-polar (LHCP) components covering a surface that approximated a semi-sphere. The Propsound channel sounder from Elektrobit was used. It provided an “instantaneous” data set consisting of one “complex” (I and Q) channel response as functions of delay per patch antenna and polarization. The measurements were carried out at several representative buildings, i.e., Graz and Vienna airports, Graz conference room, Graz residential house, Graz shopping center, Vienna FFG, Vienna Millen nium Tower 22nd and 44th fl oors. An extensive measurement campaign was also realized in [69] to properly characterize the SIMO high-altitude platform-to-indoor channel in S band for several indoor scenarios, similar to those examined in [66].


For satellite/high-altitude platform-to-indoor propaga tion, the building penetration (entry) loss due to the presence of a building wall, windows, and other building features, and the delay spread of the received energy, are the key factors in order to ensure signal acquisition and tracking. The penetra tion loss is usually defi ned as the difference between the mean received signal power in the local environment close to the building and the mean signal power inside the building. In general, it is desired to obviate deep fades and large values of penetration loss encountered to increase the positioning accu racy. In addition, knowledge of the extent of the building penetration loss is necessary for retaining indoor coverage from transmitting stations placed outside a building, such as satellites.

In [66], measurement results in terms of the entry loss were presented as a function of building type, elevation, and building entry angle. Although the measured values of the penetration loss were high in general, it was shown that the lighter construction, the lower the loss. The direct indoor cov-erage was restricted to rooms with external walls looking toward the satellite. Based on the measurements, an empirical model for the entry loss as a function of the building entry

Figure 8. A simple representation of the multi-antenna satellite/high-altitude-platform to indoor-propagation radio channel.



(grazing) angle, grψ , with respect to the external wall was developed. This angle constitutes a critical geometrical parameter [69], and incorporates both elevation and azimuth angles. It was shown that the entry loss is given by

[dB] grL A Bψ= − , (1)

where the parameters A and B were demonstrated in [66, Table XVIII] for each propagation environment. Figure 9 depicts the average values of the entry loss of all tested build-ings, showing the trend described above. One observed that the highest entry losses occurred for the elevations between 15° and 30°, with decreasing loss between 30° and 60°. The entry loss also decreased with increasing entry angle, since the entry angle was getting closer to normal incidence.

Based on similar measurements, two sets of parameters were extracted in [69]: The fi rst was related to the entry loss, and the second to the time and angle dispersion effects. For extracting the entry loss, the measured averaged power delay profi les, APDPs, were compared with a reference measure-ment carried out outside each building. In Table 6, the mini-mum and the maximum values for the penetration loss for each tested building are presented. The measurements also enabled the derivation of an empirical formula for the estima tion of the building entry loss:

[dB] 28.5 0.12L α= − , (2)

where α is the building entry angle, ranging from 0° to 90°.

5. Conclusions and Future Research Perspectives

As satellite-communication infrastructures have been widely used for the provision of communication services, the idea of implementing and experimenting with multiple anten-nas on both sides of the link in outdoor and indoor conditions allows for a further expansion of the boundaries of satellite systems’ performance. It is envisaged that multi-antenna sat-ellite systems will potentially be capable of providing and delivering a compelling range of current and next-generation services. Most of the research efforts have been directed toward applying MIMO in mobile satellite systems rather than fi xed satellite systems, since mobile satellite systems usually exhibit multipath propagation near the terrestrial end of the satellite link. By validating the advantages of applying MIMO technology to satellite networks, the satellite operators and system designers will design and construct new types of satel lite broadcasting systems.

The experimental results described the benefi ts of polari-zation and satellite diversity, mainly in terms of the achievable data rate. They suggested that exploiting dual-polarization fairly better succeeds in upgrading the system performance than invoking two distinct satellite transmitters. Nevertheless, several critical issues should be readdressed and revised before offi cial system implementations take place. Specifi cally, the results underlined that higher correlation is main tained for the dual-polarized antennas due to the co-located antennas, high availability land mobile satellite systems give prominence to spatial diversity rather than polarization diver sity at the receiver,

Figure 9. The average penetration-loss values for several indoor propagation environments and different elevation angles.

and the two-satellite diversity prospers when short interleavers are considered.

The results also examined particular scenarios with dis-tinct characteristics and underlined several special circum-stances. For instance, although land mobile satellite MIMO systems are preferred, the performance of land mobile satellite SIMO systems for low outage probability is adequate. More-over, a contra-wound quadrifi lar helix antenna can be used instead of spatially separated reference antennas to overcome space limitations and achieve signifi cant capacity improve-ment, while dual circular polarization multiplexing can be used to attain the benefi ts of MIMO technology over highly correlated channels and low SNR. Furthermore, the results highlighted practical issues. They reported that the correlation coeffi cient between the MIMO channels and the cross-polari-zation discrimination are functions of the strength of the line-of-sight component and the density of the scatterers in non-line-of-sight environments, and increase as the Rice K-factor increases and the multipath becomes sparse. The correlation and the cross-polarization discrimination are also directly related to the geometry of the link, i.e., the azimuth and eleva-tion angles, the orientation of the antenna arrays, and the excess delay. In addition, the results revealed the demand for hybrid terrestrial-satellite confi gurations to preserve satisfac tory quality of service in areas where high C/N is necessary, e.g., urban areas.

Although the results from current real-world channel-sounding measurement campaigns constitute a basis for the characterization of the multi-antenna satellite channel, and are indicative of a promising evolution for MIMO satellite com munications, the experiments were performed in specifi c areas, where the infl uences of the fl uctuating direct and dif fuse components of the signal signifi cantly differ. Future research efforts may therefore be devoted to collecting meas ured channel data in various outdoor and indoor areas, to improve

and/or extend the validity of current results, and to accurately determine the benefi ts of MIMO technology over satellite systems. Accurate channel models for multi-antenna satellite systems can then be developed forasmuch as thor oughly validated against experimental data. The most promising ΜΙΜΟ satellite and hybrid satellite scenarios from a system point of view are [83]: a) a GEO sat-ellite with two orthogonally polarized antennas set up as a dual polarization per beam payload, and a satellite terminal with the two collocated orthogonally polarized (RHCP/LHCP) receiver antennas; and b) a hybrid satellite/terrestrial system with one satellite and one terrestrial base station or repeater jointly transmitting data to users, employing either single or dual polarized antennas in a single and in multi-frequency networks. For these confi gurations, further experimental cam paigns should be conducted.

Sophisticated pre-coding [92] and space-polarization-time coding – e.g., Golden codes [93] – techniques can be utilized and experimentally tested and then introduced into the DVB - Second Generation (DVB-S2) and DVB-SH standards. Moreover, experimental characterization of land mobile satel-lite MIMO systems operating at frequencies above 10 GHz is necessary in order to introduce mobility into DVB-S2 systems. This is also needed to study the performance of future broad-band applications, such as the provision of high-speed Internet access, audio and video on demand, and fi le transfer to vehi-cles, airplanes, trains, and ships. Both local environment propagation effects, e.g., multipath, shadowing, and blockage due to the local environment in the vicinity of the terrestrial receiver, and tropospheric effects, e.g., rainfall, oxygen absorption, water vapor, clouds, and precipitation, are then involved, as shown by some preliminary studies [94-99]. In this regard, several measurement campaigns at the Ku and Ka bands were previously conducted for conventional land mobile satellite SISO systems [18, 21]. The DVB – Return Channel via Satellite for Mobile Applications (DVB-RCS+M) specifi -cation [100] has been recently approved. Finally, it could be interesting to investigate the feasibility and possible benefi ts of tri-polarized MIMO [101] in land mobile satellite scenarios, with reference to data-rate enhancement and the robustness of the MIMO performance.

6. Acknowledgments

This work was co-fi nanced by the European Union (Euro-pean Social Fund – ESF) and Greek national funds through the Operational Program “Education and Lifelong Learning” of the National Strategic Reference Framework (NSRF) – Research Funding Program THALES MIMOSA (MIS: 380041) Investing in knowledge society through the European Social Fund. The authors would like to thank the Editor and the anonymous reviewers, whose useful and con structive comments helped to improve the original version of the manuscript.

Table 6. The minimum and maximum penetration losses for several indoor propagation environments at S band.

Elevation Angle Range 15°-60° Penetration Loss (dB)

Graz Airport - Conference room 7.3-23.3Graz Airport - Gate 10 15.6-23.3Graz Airport - Shopping mal 24.2-38.3Graz Airport - Residential house 23.1-33.8Vienna international airport 16.7-27.3Millennium Tower - fl oor 22 22.1-32.1Millennium Tower - fl oor 44 14.2-27.6Offi ce Building 15.4-28.3



7. References

1. B. Evans, M. Werner, E. Lutz, M. Bousquet, G. E. Corazza, G. Maral, and R. Rumeau, “Integration of Satellite and Ter-restrial Systems in Future Multimedia Communications,” IEEE Wireless Communications, 12, 5, October 2005, pp. 72-80.

2. R. Giuliano, M. Luglio, and F. Mazzenga, “Interoperability Between WiMAX and Broadband Mobile Space Networks,” IEEE Communications Magazine, 46, 3, March 2008, pp. 50-57.

3. S. Kota, G. Giambene, and S. Kim, “Satellite Component of NGN: Integrated and Hybrid Networks,” International Jour nal of Satellite Communications and Networking, 29, 3, May 2011, pp. 191-208.

4. A. J. Paulraj, D. A. Gore, R. U. Nabar, and H. Bolcskei, “An Overview of MIMO Communications – A Key to Gigabit Wireless,” Proceedings of the IEEE, 92, 2, February 2004, pp. 198-218.

5. P.-D. Arapoglou, K. Liolis, M. Bertinelli, A. Panagopoulos, P. Cottis, and R. De Gaudenzi, “MIMO over Satellite: A Review,” IEEE Communications Surveys & Tutorials, 13, 1, First Quarter 2011, pp. 27-51.

6. P.-D. Arapoglou, E. T. Michailidis, A. D. Panagopoulos, A. G. Kanatas, and R. Prieto-Cerdeira, “The Land Mobile Earth-Space Channel: SISO to MIMO Modeling from L- to Ka-Bands,” IEEE Vehicular Technology Magazine, 6, 2, June 2011, pp. 44-53.

7. ETSI EM 302 583, “Digital Video Broadcast (DVB); Framing Structure, Channel Coding and Modulation for Satel-lite Services to Handheld Devices (SH) Below 3 GHz,” 2007.

8. A. Bolea Alamanac, P. Burzigotti, R. De Gaudenzi, G. Liva, H. Nghia Pham, and S. Scalise, “In-Depth Analysis of the Sat ellite Component of DVB-SH: Scenarios, System Dimen-sioning, Simulations and Field Trial Results,” International Journal of Satellite Communications and Networking, 27, 4-5, July-October 2009, pp. 215-240.

9. http://www.dvb.org/technology/dvb-ngh.

10. M. Sangchul, K. Woo-Suk D. Vargas, D. Gozalvez Serrano, M. D. Nisar, and V. Pauli, “Enhanced spatial multi plexing for rate-2 MIMO of DVB-NGH system,” Proceedings of the 19th International Conference on Telecommunications (ICT) 2012, Jounieh, Lebanon, 23-25 April 2012, pp. 1-5.

11. M. A. Jensen and J. W. Wallace, “A Review of Antennas and Propagation for MIMO Wireless Communication,” IEEE Transactions on Antennas and Propagation, AP-52, 11, November 2004, pp. 2810-2824.

12. J. Goldhirsh and W. J. Vogel, “Mobile Satellite Systems Fade Statistics for Shadowing and Multipath from Roadside Trees at UHF and L-Band,” IEEE Transactions on Antennas and Propagation, AP-37, 4, April 1989, pp. 489-498.

13. J. Dutronc and J. N. Colcy, “Land Mobile Communica-tions in Ku-Band. Results of a Test Campaign on Eutelsat I-F1,” International Journal of Satellite Communications, 8, 1, January/February 1990, pp. 43-63.

14. E. Lutz, D. Cygan, M. Dippold, F. Dolainsky, and W. Papke, “The Land Mobile Satellite Communications Channel - Recording, Statistics, and Channel Model,” IEEE Transac tions on Vehicular Technology, 40, 2, May 1991, pp. 375-386.

15. A. Benarroch and L. Mercader, “Signal Statistics Obtained from a LMSS Experiment in Europe with the Marecs Satel lite,” IEEE Transactions on Communications, 42, 234, Febru ary/March/April 1994, pp. 1264-1269.

16. A. G. Kanatas and P. Constantinou, “City Center High Elevation Angle Propagation Measurements at L-Band for Land-Mobile Satellite Systems,” IEEE Transactions on Vehicular Technology, 47, 3, August 1998, pp. 1002-1011.

17. B. Belloul, S. R. Saunders, M. A. N. Parks and B. G. Evans, “Measurement and Modelling of Wideband Propaga-tion at L and S-Bands Applicable to the LMS Channel,” IEE Proceedings – Microwaves, Antennas and Propagation, 147, 2, April 2000, pp. 116-121.

18. E. Kubista, F. Perez-Fontan, M. A. Vazquez-Castro, S. Buonomo, B. Arbesser-Rastburg, and J. P. Poiares Baptista, “Ka-Band Propagation Measurements and Statistics for Land Mobile Satellite Applications,” IEEE Transactions on Vehicular Technology, 49, 3, May 2000, pp. 973-983.

19. F. Pérez-Fontán, M. Vázquez-Castro, C. E. Cabado, J. P. Garcia, and E. Cubista, “Statistical Modeling of the LMS Channel,” IEEE Transactions on Vehicular Technology, 50, 6, November 2001, pp. 1549-1567.

20. M. Döttling, A. Jahn, D. Didascalou, W. Wiesbeck, “Two and Three-Dimensional Ray Tracing Applied to the Land Mobile Satellite (LMS) Propagation Channel,” IEEE Antennas and Propagation Magazine, 43, 6, December 2001, pp. 27-37.

21. S. Scalise, H. Ernst, and G. Harles, “Measurement and Modeling of the Land Mobile Satellite Channel at Ku-Band,” IEEE Transactions on Vehicular Technology, 57, 2, March 2008, pp. 693-703.

22. Abele, F. Perez-Fontan, M. Bousquet, P. Valtr, J. Lemorton, F. Lacoste, and E. Corbel, “A New Physi cal/Statistical Model of the Land Mobile Satellite Propagation Channel,” Proceedings of the 4th European Conference on Antennas and Propagation (EuCAP) 2010, Barcelona, Spain, April 12-16, 2010, pp. 1-5.

23. H. Vasseur, “Degradation of Availability Performance in Dual-Polarized Satellite Communications Systems,” IEEE Transactions on Communications, 48, 3, March 2000, pp. 465-472.

24. C. Oestges and D. Vanhoenacker-Janvier, “A Physical-Statistical Shadowing Correlation Model and its Application to Low-Earth-Orbit Systems,” IEEE Transactions on Vehicu lar Technology, 50, 2, March 2001, pp. 416-421.

25. M. Vazquez-Castro, F. Perez-Fontan, and S. R. Saunders, “Shadowing Correlation Assessment and Modeling for Satel-lite Diversity in Urban Environments,” International Journal of Satellite Communications, 20, 2, March/April 2002, pp. 151-166.

26. C. Oestges, “A Stochastic Geometrical Vector Model of Macro- and Megacellular Communication Channels,” IEEE Transactions on Vehicular Technology, 51, 6, November 2002, pp. 1352-1360.

27. P. R. King, B. G. Evans, and S. Stavrou, “Physical-Statis-tical Model for the Land Mobile-Satellite Channel Applied to Satellite/HAP MIMO,” Proceedings of the 11th European Wireless Conference 2005, Nicosia, Cyprus, April 2005, pp. 198-204.

28. P. R. King and S. Stavrou, “Land Mobile-Satellite MIMO Capacity Predictions,” Electronics Letters, 41, 13, June 2005, pp. 749-751.

29. F. Yamashita, K. Kobayashi, M. Ueba, and M. Umehira, “Broadband multiple satellite MIMO system,” Proceedings of the 62nd IEEE Vehicular Technology Conference (VTC) 2005, 4, Dallas, USA, September 2005, pp. 2632-2636.

30. M. Sellathurai, P. Guinand, and J. Lodge, “Space-Time Coding in Mobile Satellite Communications using Dual-Polarized Channels,” IEEE Transactions on Vehicular Tech-nology, 55, 1, January 2006, pp. 188-199.

31. P. R. King and S. Stavrou, “Characteristics of the Land Mobile Satellite MIMO Channel,” Proceedings of the IEEE 64th Vehicular Technology Conference (VTC-Fall) 2006, Montréal, Canada, September 25-28, 2006, pp. 1-4.

32. P. R. King and S. Stavrou, “Capacity Improvement for a Land Mobile Single Satellite MIMO System,” IEEE Antennas and Wireless Propagation Letters, 5, 1, December 2006, pp. 98-100.

33. P. R. King and S. Stavrou, “Low Elevation Wideband Land Mobile Satellite MIMO Channel Characteristics,” IEEE Transactions on Wireless Communications, 6, 7, July 2007, pp. 2712-2720.

34. P. Horvath, G. K. Karagiannidis, P. R. King, S. Stavrou, and I. Frigyes, “Investigations in Satellite MIMO Channel

Modeling: Accent on Polarization,” EURASIP Journal on Wireless Communications and Networking, 2007: 098942, 7 May 2007. doi:10.1155/2007/98942.

35. K. P. Liolis, A. D. Panagopoulos, P. G. Cottis, “Multi-Sat-ellite MIMO Communications at Ku-Band and Above: Inves-tigations on Spatial Multiplexing for Capacity Improvement and Selection Diversity for Interference Mitigation,” EURASIP Journal on Wireless Communications and Net working, 2007: 059608, 8 July 2007. doi:10.1155/2007/59608.

36. R. T. Schwarz, A. Knopp, D. Ogermann, C. A. Hofmann, B. Lankl, “Optimum-Capacity MIMO Satellite Link for Fixed and Mobile Services,” Proceedings of the International ITG Workshop on Smart Antennas (WSA) 2008, Darmstadt, Ger-many, February 26-27, 2008, pp. 209-216.

37. A. Heuberger, H. Stadali, A. Del Bianco, A. Bolea Alamanac, R. Hoppe, and O. Pulvirenti: “Experimental Vali-dation of Advanced Mobile Broadcasting Waveform in S-Band,” Proceedings of the 4th Advanced Satellite Mobile Systems Conference (ASMS) 2008, Bologna, Italy, August 26-28, 2008, pp. 140-148.

38. A. Mohammed and T. Hult, “Performance Evolution of a MIMO Satellite Diversity System,” Proceedings of the 10th International Workshop on Signal Processing for Space Com-munications (SPSC) 2008, Rhodes, Greece, October 6-8, 2008, pp. 1-5.

39. N. Zorba, M. Realp, M. A. Lagunas, A. I. Perez-Neira, “Dual Polarization for MIMO Processing in Multibeam Satel-lite Systems,” Proceedings of the 10th International Workshop on Signal Processing for Space Communications (SPSC) 2008, Rhodes, Greece, October 6-8, 2008, pp. 1-7.

40. A. Heuberger, “Fade Correlation and Diversity Effects in Satellite Broadcasting to Mobile Users in S-Band,” Interna-tional Journal of Satellite Communications and Networking, 26, 5, September/October 2008, pp. 359-379.

41. U. M. Ekpe, T. Brown, and B. G. Evans, “Unleashing the Polarisation Domain for Land Mobile Satellite MIMO Sys tems,” Proceedings of the 3rd European Conference on Antennas and Propagation (EuCAP) 2009, Berlin, Germany, March 23-27, 2009, pp. 2288-2291.

42. M. Milojevic, M. Haardt, E. Eberlein, and A. Heuberger, “Channel Modeling for Multiple Satellite Broadcasting Sys-tems,” IEEE Transactions on Broadcasting, 55, 4, December 2009, pp. 705-718.

43. F. Lacoste, F. Carvalho, F. Perez-Fontan, A. Nunez Fernandez, V. Fabbro, and G. Scot, “MISO and SIMO Meas-urements of the Land Mobile Satellite Propagation Channel at S-Band,” Proceedings of the 4th European Conference on Antennas and Propagation (EuCAP) 2010, Barcelona, Spain, 12-16 April 2010, pp. 1-5.



44. O. Pulvirenti, A. Del Bianco, R. Hoppe, D. Ortiz, M. Pannozzo, S. Sudler: “Performance Assessment Based on Field Measurements of Mobile Satellite Services Over Hybrid Networks in S-Band,” Proceedings of the 5th Advanced Satel-lite Multimedia Systems Conference (ASMS) and the 11th Signal Processing for Space Communications (SPSC) Work-shop 2010, Paris, France, September 13-15, 2010, pp. 315-324.

45. G. Alfano, A. De Maio, and A. M. Tulino, “A Theoretical Framework for LMS MIMO Communication Systems Per-formance Analysis,” IEEE Transactions on Information The-ory, 56, 11, November 2010, pp. 5614-5630.

46. K. P. Liolis, J. G. Vilardeb, E. Casini, and A. Perez-Neira, “Statistical Modeling of Dual-Polarized MIMO Land Mobile Satellite Channels,” IEEE Transactions on Communications, 58, 11, November 2010, pp. 3077-3083.

47. L. Xing and L. Youjian, “A 3-D Channel Model for Dis-tributed MIMO Satellite Systems,” Proceedings of the IEEE Global Telecommunications Conference (GLOBECOM) 2010, Miami, Florida, USA, December 6-10, 2010, pp. 1-5.

48. P.-D. Arapoglou, M. Zamkotsian, and P. Cottis, “Dual Polarization MIMO in LMS Broadcasting Systems: Possible Benefi ts and Challenges,” International Journal of Satellite Communications and Networking, 29, 4, July/August 2011, pp. 349-366.

49. M. F. B. Mansor, T. W. C. Brown, and B. G. Evans, “Sat-ellite MIMO Measurement With Colocated Quadrifi lar Helix Antennas at the Receiver Terminal,” IEEE Antenna and Wireless Propagation Letters, 9, 2010, pp. 712-715.

50. E. Eberlein, F. Burkhardt, C. Wagner, A. Heuberger, D. Arndt, and R. Prieto-Cerdeira, “Statistical evaluation of the MIMO gain for LMS channels,” Proceedings of the 5th Euro-pean Conference on Antennas and Propagation (EuCAP) 2011, Rome, Italy, April 11-15, 2011, pp. 2695-2699.

51. D. Arndt, A. Ihlow, A. Heuberger, and E. Eberlein, “Antenna Diversity for Mobile Satellite Applications: Per formance Evaluation Based on Measurements,” Proceedings of the 5th European Conference on Antennas and Propagation (EuCAP) 2011, Rome, Italy, April 11-15, 2011, pp. 3729-3733.

52. T. W. C. Brown and A. Kyrgiazos, “On the Small Scale Modelling Aspects of Dual Circular Polarized Land Mobile Satellite MIMO Channels in Line of Sight and in Vehicles,” Proceedings of the 5th European Conference on Antennas and Propagation (EuCAP) 2011, Rome, Italy, April 11-15, 2011, pp. 3562-3565.

53. A. I. Pérez-Neira, C. Ibars, J. Serra, A. del Coso, J. Gómez-Vilardebó, M. Caus, and K. P. Liolis, “MIMO Chan-nel Modeling and Transmission Techniques for Multi-Satellite and Hybrid Satellite-Terrestrial Mobile Networks,” Physical Communication, 4, 2, June 2011, pp. 127-139.

54. U. M. Ekpe, T. W. C. Brown, and B. G. Evans, “Channel Characteristics Analysis of the Dual Circular Polarized Land Mobile Satellite MIMO Radio Channel,” Proceedings of the IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications 2011, Torino, Italy, September 12-16, 2011, pp. 781-784.

55. E. Eberlein, F. Burkhard, G. Sommerkorn, S. Jaeckel, and R. Prieto-Cerdeira, “MIMOSA – Analysis of MIMO Channel for LMS Systems,” Proceedings of the ESA Propagation Workshop, ESTEC, Noordwijk, Netherlands, November 2011. 56. T. Heyn, D. Arndt, E. Eberlein “MiLADY CCN: Mobile Satellite Channel Model for Satellite-Angle Diversity,” Pro-ceedings of the ESA Propagation Workshop, ESTEC Noord-wijk, Netherlands, November 2011.

57. A. Knopp, R. T. Schwarz, and B. Lankl, “MIMO System Implementation with Displaced Ground Antennas for Broad-band Military SATCOM,” Proceedings of the Military Com-munications Conference (MILCOM) 2011, Baltimore, USA, 7-10 November 2011, pp. 2069-2075.

58. P. R. King, T. W. C. Brown, A. Kyrgiazos, and B. G. Evans, “Empirical-Stochastic LMS-MIMO Channel Model Implementation and Validation,” IEEE Transactions on Antennas and Propagation, AP-60, 2, February 2012, pp. 606-614.

59. M. Cheffena, F. Perez-Fontan, F. Lacoste, E. Corbel, H. Mametsa, and G. Carrie, “Land Mobile Satellite Dual Polar-ized MIMO Channel Along Roadside Trees: Modeling and Performance Evaluation,” IEEE Transactions on Antennas and Propagation, AP-60, 2, February 2012, pp. 597-605.

60. F. Lacoste, J. Lemorton, L. Casadebaig, and F. Rousseau, “Measurements of the Land Mobile and Nomadic Satellite Channels at 2.2 GHz and 3.8 GHz,” Proceedings of the 6th European Conference on Antennas and Propagation (EuCAP) 2012, Prague, Czech Republic, April 26-30, 2012, pp. 2422-2426.

61. G. Carrie, F. Perez-Fontan, F. Lacoste, and J. Lemorton, “A Generative MIMO Channel Model: Encompassing Single Satellite and Satellite Diversity Cases,” Proceedings of the 6th European Conference on Antennas and Propagation (EuCAP) 2012, Prague, Czech Republic, April 26-30, 2012, pp. 2454-2458.

62. B. Shankar, P.-D. Arapoglou, and B. Ottersten, “Space-Frequency Coding for Dual Polarized Hybrid Mobile Satellite Systems,” IEEE Transactions on Wireless Communications, 11, 8, August 2012, pp. 2806-2814.

63. N. Moraitis, P. Horváth, P. Constantinou, and I. Frigyes, “On the Capacity of a SIMO Land Mobile Satellite System at C-Band: Polarized and Depolarized Received Field,” EURASIP Journal Wireless Communications and Networking, 2012:204, 29 June 2012. doi:10.1186/1687-1499-2012-204.

64. D. Arndt, A. Ihlow, T. Heyn, A. Heuberger, R. Prieto-Cerdeira and E. Eberlein, “State Modelling of the Land Mobile Propagation Channel for Dual-Satellite Systems,” EURASIP Journal on Wireless Communications and Net working, 2012:228, 23 July 2012. doi:10.1186/1687-1499-2012-228.

65. V. K. Sakarellos, C. I. Kourogiorgas, and A. D. Panagopoulos, “Hybrid Satellite-Terrestrial Broadband Back-haul Links: Capacity Enhancement Through Spatial Multi-plexing,” Proceedings of the 1st IEEE AESS European Con-ference on Satellite Telecommunications (ESTEL) 2012, Rome, Italy, October 2-5, 2012, pp. 1-5.

66. F. Perez-Fontan, V. Hovinen, M. Schönhuber, R. Prieto-Cerdeira, F. Teschl, J. Kyrolainen, and P. Valtr, “A Wideband Directional Model for the Satellite-to-Indoor Propagation Channel at S-Band,” International Journal Satellite Commu-nications and Networking, 29, 1, January/February 2011, pp. 23-45.

67. A. Mohammed, A. Mehmood, F.-N. Pavlidou, and M. Mohorcic, “The Role of High-Altitude Platforms (HAPs) in the Global Wireless Connectivity,” Proceedings of the IEEE, 99, 11, November 2011, pp. 1939-1953.

68. E. Cianca, R. Prasad, M. De Sanctis, A. De Luise, M. Antonini, D. Teotino, and M. Ruggieri, “Integrated Satellite-HAP Systems,” IEEE Communications Magazine, 43, 12, December 2005, pp. supl.33-supl.39.

69. F. Pérez-Fontán, V. Hovinen, M. Schönhuber, R. Prieto-Cerdeira, J. A. Delgado-Penín, F. Teschl, J. Kyröläinen, and P. Valtr, “Building Entry Loss and Delay Spread Measurements on a Simulated HAP-to-Indoor Link at S-Band,” EURASIP Journal on Wireless Communications and Networking, 2008:427352, 6 July 2008. doi:10.1155/2008/427352.

70. P.-D. Arapoglou, P. Burzigotti, M. Bertinelli, A. B. Alamanac, and R. De Gaudenzi, “To MIMO or Not To MIMO in Mobile Satellite Broadcasting Systems,” IEEE Transactions on Wireless Communications, 10, 9, September 2011, pp. 2807-2811.

71. A. M. Tulino, A. Lozano, and S. Verdu, “Impact of Antenna Correlation on the Capacity of Multiantenna Chan nels,” IEEE Transactions on Information Theory, 51, 7, July 2005, pp. 2491-2509.

72. E. T. Michailidis and A. G. Kanatas, “Three-Dimensional HAP-MIMO Channels: Modeling and Analysis of Space-Time Correlation,” IEEE Transactions on Vehicular Technology, 59, 5, June 2010, pp. 2232-2242.

73. E. T. Michailidis and A. G. Kanatas, “Capacity Optimized Line-of-Sight HAP-MIMO Channels for Fixed Wireless Access,” Proceedings of the International Workshop on Satel-lite and Space Communications (IWSSC) 2009, Siena-Tus-cany, Italy, September 2009, pp. 73-77.

74. S. N. Livieratos and P. G. Corns, “Availability and Per-formance of Single/Multiple Site Diversity Satellite Systems under Rain Fades,” European Transactions on Telecommuni-cations, 12, 1, January-February 2001, pp. 55-65.

75. A. D. Panagopoulos, P. M. Arapoglou, and P. G. Cottis “Site vs. Orbital Diversity: Performance Comparison Based on Propagation Characteristics at Ku Band and Above,” IEEE Antennas and Wireless Propagation Letters, 3, 1, December 2004, pp. 26-29.

76. C. Nagaraja and I. E. Otung, “Statistical Prediction of Site Diversity Gain on Earth-Space Paths Based on Radar Meas-urements in the UK,” IEEE Transactions on Antennas and Propagation, AP-60, 1, January 2012, pp. 247-256.

77. E. Falletti, F. Sellone, C. Spillard, and D. Grace, “Transmit and Receive Multi-Antenna Channel Model and Simulator for Communications from High Altitude Platforms,” International Journal of Wireless Information Networks, 13, 1, January 2006, pp. 59-75.

78. T. Celcer, T. Javornik, M. Mohorcic, and G. Kandus, “Virtual Multiple Input Multiple Output in Multiple High-Altitude Platform Constellations,” IET Communications, 3, 11, November 2009, pp. 1704-1715.

79. T. Hult, A. Mohammed, Z. Yang, and D. Grace, “Perform-ance of a Multiple HAP System employing Multiple Polariza-tion,” Wireless Personal Communications, 52, 1, 2010, pp. 105-117.

80. B. N. Getu and J. B. Andersen, “The MIMO Cube – A Compact MIMO Antenna,” IEEE Transactions on Wireless Communications, 4, 3, May 2005, pp. 1136-1141.

81. S. R. Saunders and A. A. Aragón-Zavala, Antennas and Propagation for Wireless Communications, Second Edition, London, UK, Wiley, 2007.

82. P. R. King, Modelling and Measurement of the Land Mobile Satellite MIMO Radio Propagation Channel, PhD Thesis, University of Surrey, 2007.

83. J. Kyröläinen, A. Hulkkonen, J. Ylitalo, A. Byman, B. Shankar, P.-D. Arapoglou, and J. Grotz, “Applicability of MIMO to Satellite Communications,” International Journal of Satellite Communications and Networking, 2013. doi: 10.1002/sat.1040.

84. R. Prieto-Cerdeira, F Pérez-Fontán, P Burzigotti, A Bolea-Alamañac, I Sanchez-Lago, “Versatile Two-State Land Mobile Satellite Channel Model with First Application to DVB-SH Analysis,” International Journal of Satellite Com munications and Networking, 28, 5-6, September-December 2010, pp. 291-315.



85. A. Schmitz-Peiffer, L. Stopfkuchen, J.-J. Floch, A. Fernandez, R. Jorgensen, B. Eisfeller, J. A. Rodriguez, S.Wallner, J.-H.Won, M. Anghileri, B. Lankl, T. Schüler, O. Balbach, and E. Colzi, “Architecture for a future C-band/L-band GNSS mission,” Inside GNSS, May/June, 2009, pp. 47-56.

86. G. Seco-Granados, J. A. Lopez-Salcedo, D. Jimenez-Banos, and G. Lopez-Risueno, “Challenges in Indoor Global Navigation Satellite Systems: Unveiling its core features in signal processing,” IEEE Signal Processing Magazine, 29, 2, March 2012, pp. 108-131.

87. J. Nielsen, S. K. Shanmugam, M. U. Mahfuz, and G. Lachapelle, “Enhanced Detection of Weak GNSS Signals Using Spatial Combining,” Navigation, Journal of The Insti-tute of Navigation, 56, 2, Summer 2009, pp. 83-95.

88. M. Milojevic, G. Del Galdo, N. Song, M. Haardt, and A. Heuberger, “Impact of the Receive Antenna Arrays on Spatio-Temporal Availability in Satellite-to-Indoor Broadcasting,” IEEE Transactions on Broadcasting, 56, 2, June 2010, pp. 171-183.

89. J. S. Colburn, Y. Rahmat-Samii, M. A. Jensen, and G. J. Pottie, “Evaluation of Personal Communications Dual-Antenna Handset Diversity Performance,” IEEE Transactions on Vehicular Technology, 47, 3, August 1998, pp. 737-744.

90. M. Zaheri, A. Broumandan, and G. Lachapelle, “Compar ing Detection Performance of Polarization and Spatial Diver sity for Indoor GNSS Applications,” Proceedings of the IEEE/ION Position Location and Navigation Symposium (PLANS) 2010, Indian Wells, California, USA, May 4-6, 2010, pp. 737-744.

91. L. Farkas and L. Nagy, “Satellite-to-indoor Wave Propa-gation Channel Simulation. First Results – The Polarization Characteristics of the Indoor Wave,” Proceedings of the 11th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC) 2000, 2, London, UK, September 2000, pp. 923-927.

92. M. Alvarez Diaz, N. Courville, C. Mosquera, G. Liva, and G. E. Corazza, “Non-Linear Interference Mitigation for Broadband Multimedia Satellite Systems,” Proceedings of the International Workshop on Satellite and Space Communica-tions (IWSSC) 2007, Salzburg, Austria, September 13-14, 2007, pp. 61-65.

93. J.-C. Belfi ore, G. Rekaya, E. Viterbo, “The Golden Code: A 2×2 Fullrate Space-Time Code with Nonvanishing Deter-minants,” IEEE Transactions on Information Theory, 51, 4, April 2005, pp. 1432-1436.

94. W. Li, C. Look Law, V. K. Dubey, and J. T. Ong, “Ka-Band Land Mobile Satellite Channel Model Incorporating Weather Effects,” IEEE Communications Letters, 5, 5, May 2001, pp. 194-196.

95. B. R. Andersen, O. Gangaas, and J. Andenaes, “A DVB/Inmarsat Hybrid Architecture for Asymmetrical Broad band Mobile Satellite Services,” International Journal of Sat ellite Communications and Networking, 24, 2, March/April 2006, pp. 119-136.

96. C. Morlet, A. Bolea Alamanac, G. Gallinaro, L. Erup, P. Takats, and A. Ginesi, “Introduction of Mobility Aspects for DVB-S2/RCS Broadband Systems,” Space Communications, 21, 1-2, December 2007, pp. 5-17.

97. A. Bolea Alamanac, P. Chan, L. Duquerroy, Y. Fun Hu, G. Gallinaro, W. Guo, and D. Mignolo, “DVB-RCS Goes Mobile: Challenges and Technical Solutions,” International Journal of Satellite Communications and Networking, 28, 3-4, May - August 2010, pp. 137-155.

98. K. P. Liolis, A. D. Panagopoulos, and S. Scalise, “On the Combination of Tropospheric and Local Environment Propa-gation Effects for Mobile Satellite Systems Above 10 GHz,” IEEE Transactions on Vehicular Technology, 59, 3, March 2010, pp. 1109-1120.

99. P. D. Arapoglou, K. P. Liolis, A. D. Panagopoulos, “Rail-way Satellite Channel at Ku Band and Above: Composite Dynamic Modeling for the Design of Fade Mitigation Tech-niques,” International Journal of Satellite Communications and Networking, 30, 1, January/February 2012, pp. 1-17.

100. EN 301 790 V1.5.1 (2008–07), Digital Video Broad-casting (DVB). Interaction Channel for Satellite Distribution Systems (DVB-RCS + M). DVB BlueBook A054r4.

101. F. Quitin, C. Oestges, A. Panahandeh, F. Horlin, and P. De Doncker, “Tri-Polarized MIMO Systems in Real-World Channels: Channel Investigation and Performance Analysis,” Physical Communication, 5, 4, December 2012, pp. 308-316.

Athanasios D. Panagopoulos was born in Athens, Greece, in 1975. He received the Diploma in Electrical and Computer Engineering (summa cum laude) and the DrEng from the National Technical University of Athens (NTUA), Athens, in July 1997 and in April 2002, respectively. From May 2002 to July 2003, he served the Technical Corps of the Hellenic Army. From September 2003 to December 2008, he worked as Assistant Professor in the School of Pedagogical and Technological Education. From January 2005 to May 2008, he was the Head of the Wireless & Satellite Division of Hellenic Authority for Communication Security and Privacy. In 2008, he became a Faculty Member at the School of Elec-trical and Computer Engineering of NTUA, where he is now Assistant Professor. He is author and coauthor of more than 100 journal and transactions papers, and more than 150 book chapters and conference proceedings papers. He has more than 20 ITU-R contributions and three publications in Hellenic technical journals. He was the recipient of URSI General Assembly Young Scientist Awards in 2002 and in 2005. He was co-recipient of the 3rd place Best Paper Award in the 2006 IEEE Radio and Wireless Communication Symposium. He has participated in many national and European R&D pro jects. He was a member of the Technical Program Committee in many international conferences and he has been Guest Edi tor for many special issues. He serves on the editorial boards of the Elsevier Physical Communication Journal, and he is an Associate Editor of the IEEE Transactions on Antennas and Propagation and the IEEE Communication Letters. His research interests include radio communications, wireless and satellite communications networks, spectrum and energy effi cient techniques, mobile computing technologies, and the physical layer impact on higher communication protocols.

Introducing the Feature Article Authors

Petropoulou Paraskevi was born in Athens, Greece, in 1989. She received the MSc in Digital Communications and Networks from the University of Piraeus, Piraeus, Greece, in 2013. Since 2010, she has been a Researcher and a Laboratory Instructor with the Department of Digital Systems, University of Piraeus. Her main research interests include mobile and satellite communications, radio channel characterization, polarization techniques, and MIMO system architectures.

Emmanouel T. Michailidis was born in Athens, Greece, in 1980. He received the PhD in broadband wireless commu-nications from the University of Piraeus, Piraeus, Greece, in May 2011. Since March 2012, he has been a Postdoctoral Researcher in satellite communications with the Department of Digital Systems, School of Information and Communica-tion Technologies, University of Piraeus. Since October 2007, he was a Laboratory Instructor with the Department of Elec-tronics Engineering, School of Technological Applications, Technological Educational Institute (TEI) of Piraeus. His cur-rent research interests include channel characterization, mod-eling, and simulation for future wireless and satellite commu-nication systems, and new transmission schemes for coopera tive and MIMO systems. Dr. Michailidis received the Best Paper Award at the Second International Conference on Advances in Satellite and Space Communications (SPACOMM) in 2010. He serves on the editorial board of the International Journal on Advances in Telecommunications.



Athanasios G. Kanatas received the Diploma in electri-cal engineering from the National Technical University of Athens (NTUA), Athens, Greece, in 1991; the MSc in satellite communication engineering from the University of Surrey, Surrey, UK, in 1992; and the PhD in mobile satellite commu-nications from NTUA in February 1997. From 1993 to 1994, he was with the National Documentation Center, National Research Institute. In 1995, he joined SPACETEC Ltd. as a Technical Project Manager for the VISA/EMEA VSAT Pro ject in Greece. In 1996, he joined the Mobile Radiocommuni cations Laboratory as a Research Associate. From 1999 to 2002, he was with the Institute of Communication and Com puter Systems. In 2000, he became a Member of the Board of Directors of OTESAT S.A. In 2002, he joined the University of Piraeus, where he is a Professor with the Department of Digital Systems, School of Information and Communication Technologies. His current research interests include the devel opment of new digital techniques for wireless and satellite communication systems; channel characterization, simulation, and modeling for mobile, mobile satellite, and future wireless communication systems; antenna selection and radio-fre quency preprocessing techniques; new transmission schemes for multiple-input multiple-output systems; and energy-effi cient techniques for wireless sensor networks. Dr. Kanatas was elected Chair of the IEEE Communications Society for the Greek Section in 1999.

Radio Planning of Single-Frequency NetworksforBroadcastingDigitalTVin

Mixed-TerrainRegions

Nektarios Moraitis1, Panagiotis N. Vasileiou2, Constantine G. Kakoyiannis1, Athanasios Marousis1, Athanasios G. Kanatas2, and Philip Constantinou1

1Mobile Radiocommunications LaboratoryNational Technical University of Athens

9, Heroon Polytechniou St., GR-15773, Zographos Campus, Athens, GreeceE-mail: [email protected]; [email protected]; [email protected]; [email protected]

2Telecommunication Systems Laboratory, Dept. of Digital SystemsUniversity of Piraeus

80, Karaoli & Dimitriou str., GR-18534, Piraeus, GreeceE-mail: [email protected]; [email protected]

Abstract

This paper presents a design performed for the digital terrestrial television network in Greece. Based on the initial assumptions provided by the General Secretariat of Telecommunications, and the functional requirements of modern broadcasting networks, the authors analytically describe the design methodology followed for a successful service provision in demanding mixed-terrain country. The paper presents the calculation of the network planning values, as well as the step-by-step approach adopted for the radio coverage and the synchronization studies of the planned single-frequency networks (SFNs). The proposed DVB-T network was based on the system variant B3, and consisted of 35 single-frequency networks with a minimum of eight multiplexes in each single-frequency network. Despite the diffi culties of the Greek terrain, the design proposed 191 stations, providing digital TV services to 95.9% of the population; with 84 more stations, the percentage climbed to 97.3%.

Keywords: Digital TV; digital video broadcasting; OFDM modulation; radio propagation; radio broadcasting; radio network; radio spectrum management; radiofrequency interference; TV broadcasting; TV interference

1. Introduction

The new digital terrestrial broadcasting systems achieve an effi cient use of the spectrum, allowing the deployment

of new high-quality services. In addition, part of the radio spec trum is released for other advanced uses, producing the so-called digital dividend after the fi nal switchover. Added value to these characteristics is the marked improvement in portable and mobile reception, enabling both an extremely new approach in the way of viewing, and also the integration of various technologies and services at the user end. Digital video broadcasting (DVB) specifi cations [1, 2] detail a wide range of technical parameters, such as the number of OFDM carriers, the length of the guard interval, the degree of error protection, and the modulation method that the network operators can select,

allowing a balance between the data rate and the transmission reliability.

The demand for a common digital broadcasting regula-tion framework from as many countries as possible, and the requirement for international coordination, have led to the establishment of common rules described in Final Acts of the Regional Radiocommunications Conference (RRC-06) in Geneva (GE’06). The GE’06 Plan covers the frequency bands 174 MHz to 230 MHz (Band III) and 470 MHz to 862 MHz (Bands IV/V) [3]. Moreover, the digital terrestrial broadcast-ing platform is widely supported by manufacturers, network operators, broadcasters, regulators, and the public, since regu-latory clarity and certainty are provided to make the right investments in future technology and services [4, 5]. The main


Radio Propagation Channel Measurements for Multi-Antenna...

Documents

Transcript of Radio Propagation Channel Measurements for Multi-Antenna...