Y. Elgholb Satellite Communication: Key Enabling Technologies 1

Satellite Communication: Key Enabling Technologies

Youssef El Gholb Digicomm Group, Department of Electronic, and Information Technologies University of Bologna, Bologna, Italy.

Abstract—Satellites have proven to be access for public and private networks. Moreover, indispensable for universal communication national borders do not affect transmission via networking in support of a variety of personal, satellite and its cost is not distance-related. commercial,and security applications. In an For business, users the attraction is the ability to attempt and effort to remain competitive with establish a network specifically dimensioned for the terrestrial systems, in the context of increasing required service in terms of demand, performance, requirement for the future communication and geographical distribution, with the capability to systems. The rapid increase of capacity of add growth where the market dictates. Moreover, terrestrial link in terms of generations (1G to 5G satellite terminals are more transportable than fixed in 2020) can be analogous to satellite links and they lend themselves to mobile services communications. The first generation (1G) such as those required by ships and other forms of having a capacity of 5-50 Gbps per satellite, transport and can be installed quickly without any 2010-2020; the second generation (2G) satellite existing infrastructure, and are 50-500 Gbps, and 2020-2030; as the needs thus a viable means of providing service to a increase, for instance, as far future needs of the remote location, whether this is a construction site communication for Mars human community, or a small island. Their independence from other this can be considered as third generation (3G) networks may make them more secure and offer satellite 0.5-5 Tbps. SatCom are trying to follow unrivaled back-up possibilities. the progress in terrestrial in such as: Multicarrier waveforms use, Full Duplex,SDN, In an effort to remain competitive with terrestrial MmWave, MIMO technologyand profit from the systems, SatCom are trying to follow the progress significant research achievements in the area of in terrestrial technology and profit from the multiple antenna techniques. This work presents significant research achievements in the area of an overview of technologies that revolution Waveforms, MIMO, MmWave, fullduplex terrestrial communication systems and techniques. Hence the question to answer is, are considered as key technologies for 5G with the these techniques applicable to SatCom? since they possibility of its application in satellite exhibit distinct characteristics compared to communication. terrestrial systems, with regard to service coverage, link geometry, propagation delay, channel Keywords —5G, modulation, satellite communications, impairments, interference scenarios and physical SDSN, Massive MIMO, Mm wave, Full Duplex layer interface. Moreover, we can distinguish between different SatCom systems variants 1. Introduction depending on [1]: the choice of orbit (GSO vs. NGSO), user mobility (fixed vs. mobile), operating Satellites have the advantage of coverage frequency band group size of intended users nationally, internationally, and between continents. (broadcast, multicast, unicast), scheme The coverage can be tailored for specific regions, (single carrier TDM vs. multicarrier OFDM), type and the capacity can be partitioned to provide of application (delay tolerant vs. delay intolerant),

Mediterranean Telecommunications Journal Vol. 7, N° 1, January 2017 ISSN: 2458-6765 Y. Elgholb Satellite Communication: Key Enabling Technologies 2 availability of FMTs (CCM vs. ACM) and so on. One major drawback of multicarrier systems is the This work presents an overview of technologies increase of the PAPR compared to single carrier that revolution terrestrial communication systems systems. This increase is the result of the and considered as key technologies for 5G with the superposition of a large number of statistically possibility of its application in satellite independent sub-channels, which are able to communication. constructively sum up to high peaks [5]. The problem is that practical transmission systems are 2. Waveforms peak-power limited and show nonlinear characteristics which cause spectral widening of the Multiple access schemes, the most fundamental transmit signal. Clipping is a good, example among aspect of the physical layer, to a large extent, are several existing PAPR reduction techniques[6,7], considered as the defining technical feature of each for the reduction of PAPR but not always because wireless communication generation[2]. As some part of signal clipped that threshold should everyone knows that Machine Type have to be chosen properly which is generally not Communications (MTC) and the Internet of Things chosen properly and Clipping causes in-band noise, (IoT) will be significantly important application for which causes a degradation in the BER 5G. It is obviously that a new waveform study is performance [8]. [9] gives a comprehensive required to support multiple access technology, or overview of the used techniques.The economical requires the joint design of waveforms and multiple and efficient offerings from the terrestrial networks access technologies. Multicarrier systems provide have strongly motivated the satellite community optimum adaptability to the time and frequency towards devising economical missions and use of selectivity of propagation channels, which waveforms with improved spectrally efficiency.The simplifies their equalization. This is very attractive time domain OFDM signal is a sum of a large for mobile communication channels, which are number of complex sinusoids, which means that, subject to multipath propagation and vary according to the central limit theorem, the frequently with time. They also allow for an amplitude distribution will be Gaussian, leading to adaptation to the frequency response of the channel a large PAPR of the signal. Hence, a power by using different modulation alphabets and power amplifier with a relatively large linear range is allocation for the respective subcarriers. In this way required, otherwise non-linear effects will severely an approximation to the water-filling solution can degrade the system performance, which one major be achieved and the available bandwidth can be problems in satellite communications where the used very efficiently.OFDM is a well-known power amplifier has to operate close to saturation multicarrier, thoroughly studied, and heavily region or applied a back off to bring it to linear applied waveform design principle. For instance, region causing a loss in power amplification both 4G (LTE and its evolutions so far), worldwide efficiency. But there are methods like DFT- interoperability for microwave access (WiMAX), precoding used in conjunction with CP-OFDM to [3] DVB-T and IEEE 802.11 (WiFi) use OFDM as build up single-carrier FDMA for bringing down basic signal format for carrying the data. While PAPR [10 ], Fig1. having many nice aspects, OFDM has a fundamental characteristic making it less attractive for the cellular communication system to come as it carries critical importance due to shortcomings of OFDM such as cyclic prefix (CP) overhead, high side lobes, susceptibility to carrier frequency offset (CFO) and doubly dispersive channels, and larger peak-to-average-power ratio (PAPR) [4].

Mediterranean Telecommunications Journal Vol. 7, N° 1, January 2017 ISSN: 2458-6765 Y. Elgholb Satellite Communication: Key Enabling Technologies 3

applied when the amplifier is operated in multicarrier mode.

Fig2. Satellite Channel

At the satellite transponder, the carriers are channelized through an input multiplexing (IMUX) Fig1. OFDM&SC-FDMA(additional stages in dash) filter and further amplified by a non-linear HPA. scheme Additionally, the combination of HPA non-linearity with the onboard channelizing filters, introduces non-linear inter-symbol interference (ISI) and multiple carrier power amplification introduces However, sharing the on-board high power further impairments in the form of severe non- amplifier among different uplinked carriers (links) linear adjacent channel interference (ACI) due to is attractive since it provides for economical and the generated intermodulation terms [12 ].An sustainable satellite missions. However, the non- output-multiplexing (OMUX) filter is used to linear characteristic of the satellite amplifier suppress the undesired spectral regrowth (out-of- introduces intermodulation products leading to band) caused by the non-linear amplification to Adjacent Channel Interference (ACI), thereby some extent. The desire of an improvement in degrading performance, more so for the spectrally power and spectral efficiencies triggered the efficient modulations. development of on-ground mitigation techniques including predistortion (PD) at transmitter and A typical satellite resource-sharing scenario is the equalization at receiver This is because on- joint amplification of multiple channels/ carriers [13,14]. board processing increases mass/ power using a single wideband HPA (High Power Amplifier) onboard a transparent satellite instead of consumption and is less amenable to enhancements. dedicated HPAs per channel. This allows for a With the shortcomings of OFDM, other alternatives relaxation of the payload-critical requirements on were proposed such as: F-OFDM, BFMC, GFDM mass/ power. However, signal amplification and UFMC but for these waveforms still a long way isinherently non-linear due to the HPA to go to be considered for satellite use as for now, characteristics and hence, an efficient power they are just candidate for next system generation in amplification introduces distortions limiting the use terrestrial case[15,16,17,18,19,20,21,22,23,24]. of spectrally efficient modulation schemes [11]. Once the satellite and earth station parameters are 3. MIMO fixed, the traditional approach to balancing a satellite circuit involves trade-off between MIMO-based systems take advantage of what is modulation and coding. A lower order modulation probably the last unexploited frontier in wireless requires less transponder power while using more communications, the spatial domain. The bandwidth. Conversely, higher order modulation technology in terrestrial applications spans more reduces required bandwidth, but at a significant than a decade with anintensive research[25,26,27]as increase in power. Higher order modulations face it offers many advantages and degrees-of-freedom, severe distortion and a high guard-band is usually such as: (1) spaceand multiuser diversity gain, (2)

Mediterranean Telecommunications Journal Vol. 7, N° 1, January 2017 ISSN: 2458-6765 Y. Elgholb Satellite Communication: Key Enabling Technologies 4 spatial multiplexing gain,(3) array and coding gain, and (4) interference reduction. It showed spectacular results, offering substantial leverage in E C = log det I + VD realizing the next generation gigabit wireless. R N However, MIMO is a rather generic term that encompasses a plethoraof techniques including E broad categories such as single-user, multi-user and C = log 1 + H R N distributed/virtual MIMO. Where, r = rank(HH ) = min [Tn, Rn] (number of parallel channels) and,(i= 1, ... ,r) are the positive H In the context of satellite use, study cases have been eigen values of HH . selected by ESA to investigate the application of MIMO over satellite in a series of recent technical The ergodic capacity or Shannon capacity studies [28,29,30]. The satellite channel [32,31,33]defines the maximum rate, -averaged characteristics, apart from substantially differing over all channel realizations-, which can be from those of terrestrial systems, are also very transmitted over the channel based only on the different when FS and MS systems are considered. distribution of H, reveals that, albeit no CSIT The performance of any MIMO technique depends exists, the MIMO channel capacity grows linearly dramatically on the underlying channel with min(Tn , Rn ). This remarkable outcome is the characteristics, the authors in[31]describes the main reason for the popularity of MIMO dominant propagation characteristics influencing techniques, as they achieve high data rates at no FS and MS systems.Here, also one can think about extra transmit power or bandwidth. the new extended MIMO, referred to as “Massive MIMO”, which is considered one of the most promising ingredients of the emerging 5G technology. It makes a clean break with current practice through the use of large-scale antenna systems over network and devices. Moreover, it iscommercially attractive solution since higher efficiency is possible without installing more base stations.

E C = log det I + HH Due to the variation of the complexR N channel matrix H with time. Two relevant definitions of capacity exist, namely the ergodic capacity and the outage capacity, which apply to fast and slow fading channels, respectively. The capacity formula Fig3. MIMO Scheme depends on the degree of channel knowledge or CSI at the transmitter (CSIT) and the receiver (CSIR). In the exceptional case, where the channel is perfectly known at both link ends, the MIMO 4. MmWave channel may be decomposed into rank(H) parallel SISO channels obtained through SVD. The millimeter-wave region of the electromagnetic spectrum corresponds to band frequencies of 30 GHz to 300 GHz and is sometimes called the Extremely High Frequency (EHF) range. MmWave

Mediterranean Telecommunications Journal Vol. 7, N° 1, January 2017 ISSN: 2458-6765 Y. Elgholb Satellite Communication: Key Enabling Technologies 5 spectrum is considered crucially important as a works just fine for communication between choice of new spectrum becauseof its significantly satellites. In security point of view, it is very greater bandwidth,small component/subsystem difficult to intercept this communication link, sizes, light weight, low probability of interception, unless the Jammer comes in line of sight with this better Land/Sea clutter performance and selective transmitter and receiver. Since the 60 GHz signal atmospheric attenuation are some of the does not travel far before it loses all its energy, this characteristics which make MmWave spectrum frequency comes in handy for secure short-range philosophies suitable to short range terrestrial and communications, such as local wireless area Medium to Long range Satellite Communication networks used for portable computers, where it is links[34]. Moreover, due to narrowbeamwidths of important that hackers do not tap into the data its Antennas having higher gain values, MmWave stream.In addition, because of the better side lobe systems have better angular resolutions and reduced levels of the 60 GHz transmitter/receiver antenna, a Electronic CounterMeasure vulnerability and Jammer power of few hundreds of kilowatts of increased immunity to friendly EMC/hostile power at 60 GHz is required to jam this link which interference. is not possible easily.

5. FullDuplex 140λ B = Reuse of spectral resources is a way of pushing B: Beam; D: Directivity; λ:D Wavelength transmission rates beyond current limits. Simultaneously transmitting and receiving on the same frequency has long been considered a fundamental impossibility in wireless Beamwidth is a measure of how a transmitted beam communication. Recent research activities have spreads out as it gets farther from its point of origin. sought to challenge this limit [36,37].Full Duplex In , important use of millimeter waves, it is breaks the barrier of today’s communications by desirable to have a beam that stays narrow, rather supporting bi-directional communications without than fanning out that leads to “see” small distant time or frequency duplex by transmitting and objects, much like a telescope. On the other hand, receiving at the same time and on the same MmWaves have disadvantages, which include frequency. Full-duplexcommunication is currently atmospheric absorption (shorter-wavelength signals used in many applications, e.g., wired telephones, suffer from absorption by fog, dust, and smoke.) of digital subscriber line, wireless with directional higher values at certain frequencies known as antennas, and free-space optics. The impact of full- “walls”,-The frequencies at which the atmospheric duplex links in these earlier applications is limited attenuation/absorption is high due to oxygen (at 60 to doubling the rate by providing two symmetrical GHz & 120 GHz) and water vapour (at 180 GHz)-, pipes of data flowing in opposite directions. In greater amount of path loss, higher value of contrast, in multi-user wireless systems, due to the attenuation during rain conditions and non- broadcast nature of transmission (everyone hears availability of some components[35]. For instance, everyone else), full-duplex capability has the at 60 GHz oxygen molecules will interact with potential to do more than merely doubling the rate, electromagnetic radiation and absorb the energy. e.g, it facilitates networking, collaborative This means 60 GHz is not a good frequency for use transmission, and security. Full Duplex has the in long-range radar or communications, because the potential to double the system capacity and reduce oxygen absorbs the electromagnetic radiation—and the system delay. As the reuse of spectral resources the signal. On the hand, it suitable for is a way of pushing transmission rates beyond communications between satellites (cross-linking) current limits. In the case of satellite in high earth orbit since there is almost no oxygen communications, this is achieved in multibeam in space at the geosynchronous altitudes, 60 GHz coverage and multiple polarization links [38].

Mediterranean Telecommunications Journal Vol. 7, N° 1, January 2017 ISSN: 2458-6765 Y. Elgholb Satellite Communication: Key Enabling Technologies 6

However, the satellite use poses additional complex requirements on the satellite challenges due to the power imbalance between communications payload in terms of self- transmitter and receiver, alsothe simultaneous use interference cancellation. The performance of FD of the same frequencies for both transmit and lies in between the maximum and minimum receive directions at the same time is capacity of the 2x2 MIMO system. conventionally ruled out as impractical due to the coupling caused by the large interference that a 6. SDN given transmitter generates to its own receiver, which necessitates interference cancellation that has SDN stands for Software Defined Network. The limitations because of the far-stricter size, weight software-defined concept is expected to be one and power constraints. This is why regulation and cornerstone of the 5G-air interface framework [49]. communication standards preclude the To support the diverse scenarios in 5G, the next simultaneous allocation of time and spectral generation air interface will need to access all resources to both incoming and out coming signals. available spectrum, be scalable to deliver massive An S-band, full duplex, multi-channel, capacity and massive connectivity, and be transmit/receive (T/R) module has been designed, adaptable to support new and existing services and developed, and produced in large quantities for applications with extreme requirements. phased array satellite The Software Defined Air Interface (SDAI) will applications.[39]. In[40], a phased-array antenna meet the diverse demands in 5G by reconfiguring system with multi-frequency, full-duplex operation, amongst an energy efficiency- spectral efficiency and wide-beam scanning were proposed. The new co-optimized set of combinations of the physical multi-frequency phased-array system provides wide layer building blocks, including frame structure, beam scanning and full-duplex capability using a duplex mode, waveforms and multiple access simple, low-cost architecture. The system can be scheme, modulation and coding, and spatial used for applications in mobile satellite processing scheme, etc., already mentioned above. communications. Due to the high cost associated with the design, However, in reality, the ideal gains are reduced by deployment and operation of a satellite, the life the self-interference (SI) phenomenon arising due cycle of a satellite payload is considerably longer to leakage of signal power from the transmitted (typically 15+ years). As a consequence, the waveform onto the waveform being received [9]. waveform and standards implemented on the Hence a key aspect towards incorporation of full- payload is often outdated within the lifetime of the duplex paradigm involves an analysis of the satellite. Hence, the adoption of SDR technology in tolerable self-interference levels followed by an satellite communications is highly attractive as it implementation of compensation techniques to provides the flexibility to remotely reprogram the achieve the said interference level [41,42,43,44,45]. SATCOM equipment once bug fixes, improved algorithms or new/evolving communication [46] the authors showedthat full-duplex satellite In , standards are available.In satellite context, software relaying is a promising scheme enhancing the Defined Satellite Network (SDSN) is defined spectral efficiency under certain conditions, by similar to SDN. In which data and control functions comparing with the traditional half-duplex are separated. The technology benefits from operation, despite the power imbalance between the logically centralized network state knowledge and on-board transmitted and received signals[47].In decision making that enables optimal resource [48],the authors made some preliminary allocations for dynamic packet processing and considerations on the reuse of the same frequency transmission. The SDSN network node uses for both directions of the communication between forwarding tables configured by centralized system space and ground. A dual satellite and two fixed controller to govern packet routing with embedded terrestrial antennas acting as transmitter and Layer 2 switch without requiring elaborate layer 3 receiver configuration has been chosen to avoid Mediterranean Telecommunications Journal Vol. 7, N° 1, January 2017 ISSN: 2458-6765 Y. Elgholb Satellite Communication: Key Enabling Technologies 7 control plane software implementation in every [12] Efrain Zenteno, Roberto Piazza, M.R. Bhavani Shankar, Daniel Rönnow, Björn Ottersten, “Multiple-input multiple-output satellitenode. It involves radio transmission links symbol rate signal digital predistorter for non-linear multi- carrier satellite channels” IET Communications, 2015. ISSN andencompasses associated modulation, coding, 1751-8628. and resource allocation functions with dynamic [13] Piazza, R., Bhavani Shankar, M.R., Zenteno, E., et al.: control. ‘Multicarrier digital pre-distortion/ equalization techniques for non-linear satellite channels’. Proc. 30th AIAA Int. It can be extended to address inter-satellite packet Communication Satellite Systems Conf. (ICSSC), Ottawa, routing and resource management function at the Canada, 2012 [14] Beidas, B.F., Iyer Seshadri, R., Becker, N.: ‘Multicarrier controller. The system complexity, space successive predistortion for nonlinear satellite systems’, IEEE qualification costs and energy have limited the use Trans. Commun., 2015, 63, (4), pp. 1373–1382. of powerful digital processing capability onboard [15] Ndo, G.; Hao Lin; Siohan, P., "FBMC/OQAM equalization: Exploiting the imaginary interference," Personal Indoor and the satellite so a trade of in between has to be Mobile Radio Communications (PIMRC), 2012 IEEE 23rd International Symposium on , vol., no., pp.2359,2364, 9-12 sought the far-stricter size, weight and power Sept. 2012. (SWaP) constraints [50]. [16] A. Viholainen, T. Ihalainen, T. Hidalgo Stitz, M. Renfors, and M. Bellanger, “Prototype Filter Design for Filter Bank Based Multicarrier Transmission, ” in Proc. EUSIPCO, Glasgow, Scotland, August 24-28. 2009. [17] F. Schaich, T. Wild, and Y. Chen, “Waveform contenders for I. ACKNOWLEDGMENT 5G - suitability for short packet and low latency transmissions,”in Proc. IEEE VTC Spring, Seoul, April 2014. The author would like to acknowledge the [18] F. Schaich and T. Wild, “Waveform contenders for 5G - OFDM vs. FBMC vs. UFMC,” Int. Symp. on Commun, Control and support of EU-Metalic Erasmus Mondus Signal Process. (ISCCSP), Athens, April 2014. Scholarship program. [19] Wang, X.; Wild, T.; Schaich, F.; ”Filter Optimization for Carrier Frequency and Timing Offsets in Universal Filtered Multi-Carrier System”, IEEE ISWCS14, Barcelona, August 2014. [20] Schaich,F.; Wild,T.; Chen,Y.;“Waveform contenders for 5G- II. REFERENCES suitability for short packet and low latency transmissions,” in proc. IEEE Veh. Technol. Conf. Spring (VTC’14 Spring), May 2014. [1] G. Maral, M. Bousquet, Satellite Communications Systems: [21] Wild, T.; Schaich, F.; Chen, Y.; ”5G Air Interface Design based Systems, Techniques and Technology, 4th edition, Wiley, 2002. on Universal Filtered (UF-)OFDM,” in proc. DSP14, [2] S. Verdu, Multiuser detection. Cambridge University Press, Hongkong, Aug. 2014. 1998. [22] F. Schaich and T. Wild, “Relaxed Synchronization Support of [3] T. Jiang, W. Xiang, H. H. Chen, and Q. Ni, “Multicast Universal Filtered Multi-Carrier including Autonomous Timing broadcasting services support in OFDMA-based WiMAX Advance,” IEEE Int. Symp. on Wireless Commun. Syst. systems,” IEEE Communications Magazine, vol. 45, no. 8, pp. (ISWCS), Barcelona, August 2014. 78–86, Aug. 2007. [23] Fettweis,G.; Krondorf,M.; Bittner,S., ”GFDM- [4] H. Ochiai and H. Imai, “On the distribution of the peak-to- GeneralizedFrequency Division Multiplexing,” IEEE Vehicular average power ratio in OFDM signals,” IEEE Trans. Commun., Technology Conference, VTC Spring 2009, IEEE 69th, pp.1-4, vol. 49, no. 2, pp. 282–289, Feb. 2001. 26-29 April 2009. [5] Y. G. Li and G. L. Stuber, Eds., Orthogonal Frequency Division [24] A. Seyedi and G. Saulnier, “General ICI Self-Cancellation Multiplexing for Wireless Communications. Springer, 2006, ch. Scheme for OFDM Systems,” in IEEE Transactions on Peak Power Reduction Techniques, pp. 199–244 Vehicular Technology, vol. 54, no. 1, Jan. 2005. [6] S. H. Han and J. H. Lee, “An Overview of Peak-to-average [25] A.J. Paulraj, D.A. Gore, R.U. Nabar, H. Bolcskei, "An overview Power Ratio Reduction Techniques for Multicarrier of MIMO communications - A key to gigabit wireless," in Proc. Transmission,” IEEE Wireless Commun. Mag., pp. 56–65, Apr. IEEE, vol. 92, no. 2, pp. 198-218, 2004. 2005 [26] D. Gesbert, M. Shafi, D.-S. Shiu, P.J. Smith, A. Naguib, "From [7] R. Grossand D. Veeneman,“Clipping distortion in DMT theory to practice: An overview of MIMO space-time coded systems:’ IEEE lect.Lett.,vol.29. no. 24. pp. 2080-2081, 1993. wireless systems," IEEE J. Sel. Areas Commun., vol. 21, no. 3, [8] European Union’s 7th Framework Programme: Project PHY- pp. 281-302, 2003. DYAS (PHYsical layer for DYnamic AccesS and cognitive [27] J. Mietzner, R. Schober, L. Lampe, W.H. Gerstacker, P.A. radio), Project website: www.ist-phydyas.org Hoeher,"Multiple-antenna techniques for wireless [9] S. H. Han and J. H. Lee, “An Overview of Peak-to-average communications - A comprehensive literature survey,"IEEE Power Ratio Reduction Techniques for Multicarrier Commun. Surveys Tuts., vol. 11,no. 2, 2009 Transmission,” IEEE Wireless Commun. Mag., pp. 56–65, Apr. [28] ESA Contract No. 18070/04/NL/US, Novel Intra-System 2005. Interference Mitigation Techniques and Technologies for Next [10] ESA S-OFDM, “Enhanced Multicarrier OFDM Digital Generations Broad- band Satellite Systems, 2005. Transmission Techniques for Broadband Satellite”. 2007. [29] ESA contract No. AO/1-5146/06/NL/JD, MIMO Applicability [11] Bassel F.Beidas “Intermodulation distortion in multicarrier to Satellite Networks, 2007. satellite systems: analysis and turbo Volterra equalization”, [30] ESA contract No. 21591/08/NL/AT, MIMO Technology in IEEE Trans. Commun, 2011, 59, (6), pp. 1580–1590. Satellite Communications for Interference Exploitation and Capacity Enhancement, 2008.

Mediterranean Telecommunications Journal Vol. 7, N° 1, January 2017 ISSN: 2458-6765 Y. Elgholb Satellite Communication: Key Enabling Technologies 8

[31] Pantelis-Daniel Arapoglou et al “MIMO over Satellite: A [49] T. Ulversøy, “Software defined radio: challenges and Review” IEEE COMMUNICATIONS SURVEYS & opportunities,” in IEEE Communications Surveys & Tutorials, TUTORIALS, VOL. 13, NO. 1, 2011. vols. 12, no. 4, 2010. [32] P.B. Rapajic, D. Popescu, "Information capacity of random [50] W. Chen, T. Jones, A. Macikunas, P. Thomas and E. Choi, signature multiple-input multiple-output channel," IEEE Trans. ”Software defined radio (SDR) payloads for microsatellite Commun., vol. 48, no. 8, pp. 1245-1248, 2000. missions,” in Proc. CASI Astronautics Conference, pp. 1-6, May [33] Sayantan Choudhury and Jerry D. Gibson, “Information 2010. Transmission Over fading channels” IEEE Global Telecommunications Conference, Washington,DC,USA, 2007. [34] Francesco Guidolin, Mziar Nekovee, Leonardo Ballia, Michele Zorzi, “A study on the coexistence of fixed satellite service and cellular networks in a mmWave scenario”, IEEE ICC 2015 - Wireless Communications Symposium [35] ITU-R S.465, “Reference radiation pattern for earth station antennas in the fixed-satellite service for use in coordination and interference assessment in the frequency range from 2 to 31 GHz,” Jan. 2010. [36] D. W. Bliss, P.A.Parker, A.R.Magetts, “Simultanous transmission and reception for improved wireless network perfofmance”. In Processings of IEEE Workshop on Statistical Signal Processing. 2007. [37] M. Duarte and A. Sabharwal. Full-Duplex wireless communications using off-the-self / Feasibility and first results”. In 44th Asilomar Conference on Signals, Systems, and Componnents, 2010. [38] J. Arnau, B. Devillers, C. Mosquera, and A. Pérez-Neira, “Performance study of multiuser interference mitigation schemes for hybrid broadband multibeam satellite architectures,” EURASIP J. Wirel. Commun. Netw. vol. 2012, (1), p. 132, Apr. 2012. [39] Sarjit S. Bharj, Boris Tomasic, John Turtle, Roger Turner, Gary Scalzi, and Shiang Liu, “A Full-Duplex, Multi-Channel Transmit/Receive Module for an S-Band Satellite Communications Phased Array” IEEE International Symposium on Phased Array Systems and Technology, 2010. [40] Tae-Yeoul Yun, Chunlei Wang, Paola Zepeda, Christopher T. Rodenbeck, Matthew R. Coutant, Ming-yi Li, and Kai Chang.” A 10- to 21-GHz, Low-Cost, Multifrequency, and Full-Duplex Phased-Array Antenna System” IEEE Transactions on Antenna and Propagation, Vol. 50, N°. 5, MAY 2002. [41] A. Sabharwal, P. Schniter, D. Guo, D. Bliss, S. Rangarajan, and R. Wichman, “In-band full-duplex wireless: challenges and opportunities,” IEEE J. Sel. Area Commun., vol. 32, no. 9, pp. 1637–1652, Sept. 2014. [42] E. Everett, A. Sahai, and A. Sabharwal, “Passive self- interference sup- pression for FD infrastructure nodes,” IEEE Trans. Wireless Commun., vol. 13, no. 2, pp. 680–694, Jan. 2014. [43] M. Duarte, C. Dick, and A. Sabharwal, “Experiment-Driven Characterization of Full-Duplex Wireless Systems,” IEEE Trans. Wireless Commun., vol. 11, no. 12, pp. 4296–4307, Dec. 2012. [44] D. Bharadia, E. McMilin, and S. Katti, “Full duplex radios,” in Proc. ACM Special Interest Group on DataCommunication (SIGCOMM), Hong Kong, China, Aug.2013, pp. 375–386. [45] D. Bharadia, and S. Katti, “Full duplex MIMO radios,” in 11th USENIX Symp. on Networked Systems Design and Implementation (NSDI 14), Seattle, WA, April, 2014. [46] Bhavani Shankar Mysore R, Gan Zheng , Sina Maleki, and Bjo ̈rn Ottersten, “Feasibility Study of Full-duplex Relaying in Satellite Networks” IEEE 16th International Workshop on Signal Processing Advances in Wireless Communications, 2015 [47] Eugene Grayver, Ryan Keating, Adam Parrower, “Feasibility of Full Duplex Communications for LEO” 2015 IEEE. [48] Daniel Martinan Otero, Carlos Mosquera, “Frequency Reuse in Dual Satellite Settings: an Initial Evaluation of Full Duplex Operation” Workshop on Cognitive Radios and Networks for Spectrum Coexistence of Satellite and Terrestrial Systems, IEEE ICC 2015.

Mediterranean Telecommunications Journal Vol. 7, N° 1, January 2017 ISSN: 2458-6765