Technology White Paper

Transcription

1 Technology White Paper Telecommunications Services by Satellite: enabling technologies and examples New-generation satellite telecommunication systems are based on the development of high-interactivity satellite networks, which support the implementation of broadband mesh IP networks for point-to-point and multicast transmission. The technology today is mature enough to enable the full exploitation of satellitebased solutions to complement terrestrial ones, and offers special features to connect dispersed users and provide broadband access, multimedia content distribution, and multicast applications. Mastery of on-board processing and payload technologies is a key competence to conceive and deliver advanced and cost-effective solutions. With many years experience in the conception and realization of advanced satellite platforms like Skyplex and AmerHis, Alcatel Alenia Space is a leader in the delivery of services with regenerative architectures. Leading-edge packet switching techniques have also been developed, along with the key building blocks for future technology evolutions.

2 TECHNOLOGY WHITE PAPER M. C. Comparini, A. Faure, R. Novello, J. Prat TELECOMMUNICATIONS SERVICES BY SATELLITE: ENABLING TECHNOLOGIES AND EXAMPLES On-board processing technologies are essential for the development and realization of advanced, cost-effective space solutions for emerging telecommunication services. The continuous development of the Internet, along with advances in voice and image compression techniques, has sharpened interest in multimedia services. These services enable the joint presentation of various data formats, such as moving pictures, voice, and text. The growth in emerging broadband and multimedia services drives the need for ever-increasing throughput in space-based communications processors. Satellites today play a strategic role. They complement existing terrestrial infrastructures, for example to quickly deploy telecom infrastructure in sparsely populated areas, and digital payloads are a key element in reducing the cost of user terminals and the end-toend cost of delivering information to the end customer. A significant amount of digital on-board processing is required to provide the proper channelization, switching, and user management. It enables the efficient use of satellite system resources. Advances in modulation and access techniques, in coding and decoding functionalities, and in general on-board processing and switching, contribute to the definition of today s on-board architecture and payload configurations. A new class of On-Board Processors (OBP) is required to satisfy service evolution. This implies the development of hardware elements to combine flexibility, payload cost-effectiveness, and improved per-bit delivery costs. Finally, on-board elements must be conceived that match system design and on-board resources to traffic type, and which offer a fully scalable solution. Physical and practical limitations on satellite size, weight and power set an upper limit on such processors, and ultimately limit throughput. A challenging engineering task is to define competitive hardware solutions that reconcile system needs with the maturity of the enabling technologies (devices, packaging, interconnection, etc.). OBP Systems, architectures and technology solutions OBP system and architectures Current commercial OBP systems can be classified into two main groups: regenerative and transparent. In regenerative OBP, the signals are demodulated, and the data decoded and processed, before being re-encoded and remodulated; the processing may or may not include a switching matrix based on system requirements. The carrier access type can be either Single Carrier Per Channel (SCPC, very useful for TV services), or Time Division Multiple Access (TDMA, for any type or service), while the data structures are standards-compliant. Current commercial standards are DVB-RCS (Digital Video Broadcasting-Return Channel Satellite) for up-link, and DVB- Standard (DVB-S) for down-link. They are however evolving towards DVB-S2 for down-link, and the use of an Adaptive Coding Modulation (ACM) scheme, to achieve complete flexibility and the best modulation efficiency in the communication link, according to actual conditions. Transparent OBPs implement the processing through the use of digital signal demultiplexing, different levels of routing, from classic FDMA to advanced packet switching concepts, and multiplexing; more advanced transparent systems, like the regenerative ones, also make use of Digital Beam Forming to create, with the associated antennas, a fully digital system. Regenerative OBPs offer attractive performance in terms of full connectivity, but they are strictly associated with the protocol and data structures, while transparent ones are linked only to the processed channel bandwidth; data can have any format. MPEG and ATM structures will remain the standards for several years, while the use of ACM and Multi-Order Modulation schemes will allow a better use of available bandwidth and codes. A significant expertise has been developed and consolidated in advanced coding key techniques like Turbo and LDPC (Low Density Parity Check) codes. Mixed OBP systems have been already defined and proposed for specific future applications in fully meshed networks supporting user-to-user traffic. More recently, the development of processors based on packet switching has allowed the in-flight demonstration of DVB-RCS/DVB-S2 systems, via a piggy-back OBP added to standard commercial satellite configurations. AAS OBP experience: available product portfolio and running development Alcatel Alenia Space (AAS) has built a leading position in the marketplace through significant development of the enabling technologies and products for OBP solutions, and through the deployment of its technology-based services like Skyplex and, more recently, AmerHis. In addition, the European Space Agency (ESA) and various national Agencies have co-funded projects focused on broadband multimedia applications (Artes 3, Euroskyway, Domino 2). Through these studies, a broad range of skills and know-how related to architectural and technology solutions has been consolidated. The Digital Transparent Processor (DTP) is another key product technology for both commercial (i.e. Geomobile) and 2 - Alcatel Telecommunications Review - 2 nd Quarter

3 military payloads. AAS France has a significant presence in high-performance DTP, enriched in recent years by development of the regenerative solution. The focus has been on the development of two-way satellite access solutions through the full exploitation of the DVB-RCS standard. Architectures based on packet switching, originally derived from terrestrial Alcatel switching products, SMC/MC/index.htm /projects/ehf/ are today being studied for mesh network applications, using regenerative schemes, to increase system capacity in multi-spot systems (Figure 1). Protected up-link waveform and packet switching have been also validated for future EHF (Extremely High Frequency) military satellite communications. Figure 1: Packet switching regenerative payload concept DVB-RCS uplink Terminals/ground stations SCPC/TDMA MCDDD MCDDD MCDDD signaling SWITCH signaling OBPC S/C Computer Figure 2: Skyplex technology-based communication system DVB-S2 modu. DVB-S2 modu. DVB-S2 modu. OBP Alcatel Alenia Space Italia has wide experience in regenerative systems, which started with the design and manufacture of ITALSAT satellites and continued with the conception of the Skyplex system (Figure 2). The first unit, built for ESA and EUTELSAT, was embarked as experimental equipment on Hot Bird 4. It demonstrated, for the first time in flight, the concept of an onboard DVB-S Multiplexer, with the satellite assembling signals coming from different data providers, allowing the elimination of the ground connections. A complete product family has grown up over the years, whose latest development is the OBMM (On-Board MPEG Multiplexer). downlink signal. Source This is a system evolution of the Skyplex (see insert) unit, which adds the capacity and switching capability necessary for multi-spot satellite systems. AAS-España has also worked extensively on regenerative systems, started with collaboration in the first Skyplex generation (HB4), evolving towards a multi-spot cross-connectivity concept with the AmerHis project. The in-flight AmerHis equipment demonstrated the maturity of the technology and system concept; its system evolution aims at full interoperability with third-party DVB-RCS Terminals/ground stations user terminals used in transparent systems (e.g. the Alcatel 9780). DVB-S Multiplex Skyplex is a payload designed for onboard digital multiplexing. The multiplexing facility provides much more flexibility and lower operating costs, because broadcasters can uplink services directly. Skyplex can receive video, audio and data uplink signals from several different geographic locations, and multiplex them into a single DVB downlink signal. Source DVB-S2 downlink Multimedia via Satellite Digital TV Broadcast Contribution Links Internet AMERHIS: a new AAS product is starting commercial exploitation The AmerHis system, the first regenerative satellite platform fully compliant with DVB-RCS, is embarked on the Amazonas satellite, launched by Hispasat in AmerHis has four uplink and down-link 36 MHz transponders, each one with different coverage (Europe, Brazil, North America and South America), with a maximum information rate per transponder of Mbit/s (up-link) and Mbit/s (down-link), see Figure 3. The Amer- His platform allows bi-directional broadband DVB-RCS mesh connections in one hop, and full cross-connectivity between different up-links 2 nd Quarter Alcatel Telecommunications Review - 3

4 and down-links. On the ground the system is composed of standard Return Channel Satellite Terminals (RCST), a management station, gateways for interconnection with terrestrial networks, and low-cost Video Service Providers acting as video micro-broadcasters. Furthermore, providing packet-level switching and multiplexing, it is designed to physically support IP Multicast onboard. The OBP switch is dynamically re-configured by the Management Station in order to optimize up-link and down-link resources. Figure 3: OBP Switching and beam coverage provided by AmerHis North American Coverage South American Coverage Brazilian Coverage European Coverage DVB-RCS UPLINK Amazonas Amerhis SYSTEM ARCHITECTURE DEM DEM DEM DEM MOD MOD MOD MOD Management Station: Network Control Centre Network Management System DVB-S DOWNLINK The Management Station, also developed by AAS, manages all the elements of the system. It controls the sessions, resources and connections of the user terminals. For the Amer- His user terminals, AAS chose a third-party solution, from wellknown manufacturers in the DVB-RCS world like NERA, EMS and SHIRON (Figure 4). In brief, the AmerHis system combines multiple features: Multi-beam connectivity offering wide geographical coverage; One-hop satellite mesh connection, adequate for real-time services like VoIP or video conferencing; Cheap (less than 2500 Euros) and integrated user terminal solution (1.2 m dish, 2W BUC, for 1.5 Mbit/s); Multicast embedded, thanks to replication on-board; IP application oriented, with differentiated QoS. North American Coverage South American Coverage The system implements the concept of Triple Play for All, and also supports end-user applications to show that Triple Play (voice, video and data) over satellite is a complement to other existing technologies (e.g. ADSL), and a proven alternative where no other option is available (e.g. rural areas). The service marketing launch will take place in Q2 2006, with high expectations from system operator Hispamar. The Skyplex family: from technology to added-value services The Skyplex OBP introduced some years ago the concept of a distributed up-link for digital television via satellite; the idea was to Brazilian Coverage move the MPEG2 Transport Stream (TS) multiplexing capability to the satellite. In Skyplex, the audio/video content is transmitted to the satellite with proprietary TDMA or SCPC uplinks via sparse and relatively small European Coverage Earth stations. Broadcasters in different geographical locations can independently have direct access to the satellite for multiplexing and directto-home transmission. The advantage is the elimination of contribution links and a big central up-linking facility, achieving significant operating cost reduction for individual broadcasters. The received signals are demodulated, regenerated, multiplexed on-board the satellite and down-linked in a single, standard DVB-S, multi-program transport stream. The on-board equipment receives up to 18 Quadri-Phase Shift Keying (QPSK) modulated carriers, allocated 33 MHz, and 26WD_index_0.html Figure 4: Indoor user terminals from EMS, NERA and Shiron. 4 - Alcatel Telecommunications Review - 2 nd Quarter

5 processes them to create a TDM DVB- S QPSK modulated output stream with the same global bandwidth. Up-link data structures are MPEG packets, either RS or DVB-RCS turbo encoded; and the single carrier data rate can be selected between 2 and 6 Mbit/s. The Skyplex product family, with units embarked on HB4, HB5, HB6 and W3A, has been continuously improved to offer better operational performance, and to minimize mass and power consumption. Currently, the portfolio includes the Standard Turbo Unit and the Enhanced Unit. Both configurations can work in Ku and Ka band (up-link station with a 90 cm dish and RF power less than 2W). This is possible using a Quasi Error Free endto-end transmission when up-link carriers have a Signal to Noise ratio (Ebi/No) 6.5 db (SCPC case) or 7.5 db (TDMA case). The last evolution, proven on the ground, is the Skyplex OBMM (On Board MPEG Multiplexer) on a chip. This allows DVB-RCS standard processing of up-link carriers with information rates selectable between 500 Kbit/s and 12 Mbit/s; a T stage switching matrix allows the implementation of the spot-to-spot switching of up-link carriers allocated in several 37 MHz channels. OBMM building blocks consist of multimillion-gate 0.35 µm ASICs, and Low Temperature Co-fired Ceramic (LTCC) based hybrid MCMs. EUTELSAT and AAS-I have developed ground infrastructures to provide, in both Ku and Ka bands, services like interactive distance training, business TV, Web TV, telemedicine, videoconferencing, e-commerce, and company data broadcasting, services widely used today by many institutional and commercial customers (see Figure 5). Service description: Triple Play (video, voice and data) Triple Play service has become a killer application used by incumbent operators to counteract competition, and to increase their Average Revenue Per User (ARPU). We will outline some of the features of the three components of the Triple Play service, taking into account the benefits provided by the OBP-based solution. Video Different applications may coexist, i.e. transparent video broadcasting and regenerative, low-cost micro -broadcasting. The transmission of native DVB-S video is based on MPEG-2 TS, containing several video programs in the same stream. In IP TV networks, video delivery is normally done after a user request to join a video stream, and the user is logically attached to the distribution using multicast capabilities over UDP/IP. The join to a video flow is done through the IGMP protocol. Figure 5: SkyplexNet architecture examples of two-way services Fast Internet Interactive Video streaming e-commerce Multiparty Videoconferencing Interactive e-learning Enhanced Interactive TV and WEB TV Intranet LAN to LAN Connectivity Network Voice OBP technology allows all kind of voice communications without any loss in quality. In mesh communication, the transmission delay is around 300 ms, resulting in good perceived quality. In transparent systems, the communications have to go through the hub (double-hop). This means that it does not enable telephony with the perceived quality of the PSTN/ISDN. Star topology is also allowed, through a gateway, in order to connect with users outside the satellite domain (Internet, PSTN, ISDN, etc.), also in a single hop. Data All IP applications are supported, for example by AmerHis. Different QoS levels can be given to different applications depending on user requests. The gateway provides interconnection with external networks and, consequently, any data or application server is reachable by an AmerHis user terminal. For the corporate market, OBP-based satellite can offer Intranet Access or VPN enhancement. Enabling Technologies Advances in deep sub-micron CMOS technology, driven by high-volume markets, are enabling rapid reductions in ASIC size, weight, power and cost. High-density, low-power ASIC technologies have the highest potential for meeting space processor needs. In parallel, essential progress in programmable devices (Field Programmable Gate Arrays, or FPGAs) in the space domain allows the design of flexible and scalable DSP platforms, including the software-defined radio (SDR) concept. To reduce significantly the mass and size of the satellite electronics, packaging technology needs to keep pace with the quantum leap in CMOS technology. Highly integrated Multi-Chip Modules (MCMs) are today highly reliable, advanced packaging solutions for high-throughput on-board processors. The development of multi-million gate ASICs requires advanced area array packages such as Ceramic Grid Array (CGA, Column or Ball), with flip-chip die attached to reap the full benefits of the semiconductor technology. This next generation of packaging will provide, once reliability is 2 nd Quarter Alcatel Telecommunications Review - 5

6 proven, significant mass, size and cost improvements over the present state-of-the-art MCM solutions. Optical technologies for plug-and-play, high-speed digital board interconnection have been also studied, and show very good potential to be applied in next-generation on-board systems (Figure 6). Figure 6 : Examples of enabling technologies for OBP systems (a) OBMM SoC Equipment-AAS_I (b) MC3D Board in AmerHis OBP-AAS_E (c) 8 Mgates MC3D ASIC AAS-F (d) Optical component for high-speed digital board interconnection (a) (b) The road ahead: cost-effective solutions for future market trends The aim of the road-mapping process is to identify, from system trends, the related equipment and technology breakthroughs that will be required for future broadband multimedia satellite system solutions. The life cycle of OBP products must be deeply analyzed in order to match technology evolution with the proper economic conditions, industrial constraints, and market expectations. The integrated OBP product road map will provide, in conjunction with end-to-end and digital payload roadmaps, the strategic directions for medium/ long-term R&D related to satellite broadband communication systems. The main objectives are: (c) (d) To map existing product portfolio to markets/customers/ opportunities; To review anticipated key operator requirements for the medium/long-term; To identify the techniques and technologies that need to be incorporated in the R&D plan for broadband satellite communications; To map external funding sources. Convergence between commercial and the dual-use/military OBP systems is particularly relevant in this road-mapping process. Also, for the military customer, the winning solution will be the identification of scalable platforms built around key building blocks. Complete packet switch-based OBP has been successfully developed and validated in France within the programs funded by the European Space Agency and Centre National d Etudes Spatiales (ESA and CNES). A major step forward in the definition of the new class of OBP has been achieved through the validation of key building blocks: a 36 MHz MF-TDMA DVB-RCS Multi-Carrier demodulator; 32x Gbit/s packet switch with highly flexible routing; OBP Controller with its embedded software; and DVB-S2 modulator with adaptive modulation and coding. Conclusion A long tradition in the advanced exploitation of OBP solutions allows Alcatel Alenia Space to provide flexibility and lower operating cost to service providers, through the offer of commercial and institutional satellites. The next challenge is to master the technology evolution through a harmonized roadmapping process. The objective is to offer the right solution for every user and to support, through the company s core technology assets, the most competitive solutions for the future market. A broad portfolio is available in terms of products, building blocks, and enabling technologies. Modular approaches must be pursued to conceive scalable platforms, which alone can respond effectively to the key driver of flexibility requirements, and to manage OBP product life cycles correctly. AmerHis will enter operational service in the next few weeks. This represents a significant opportunity for further system evolution and service development. Skyplex technology is a standard platform for Eutelsat, and offers interesting possibilities in emerging markets like Russia. Finally, solid and validated solutions are available for nextgeneration processors that address packet switching requirements. Alcatel Alenia Space, with its advanced products and solutions, is well positioned to take advantage of the next wave of developments in space-based telecommunications systems. Massimo Claudio Comparini is Director, Convergence - Industrial Integration and Electronics Technical Officer, Operations, Alcatel Alenia Space, Rome, Italy. Massimo.Comparini@alcatelalenia space.com Rocco Novello is Deputy Director, Power and Processing Product Line, Industrial Unit Electronics in Alcatel Alenia Space, Rome, Italy. Rocco.Novello@alcatelaleniaspace.com Alain Faure is Head of the Digital Products Department, Industrial Unit Electronics, Alcatel Alenia Space, Toulouse, France. Alain.Faure@alcatelaleniaspace.com Jose Prat is a Multimedia Systems Manager in Alcatel Alenia Space España, Madrid, Spain. Jose.prat_aparicio@alcatelaleniaspace.com 6 - Alcatel Telecommunications Review - 2 nd Quarter

7 Abbreviations ACM Adaptive Coding Modulation DSP Digital Signal Processor DVB-S Digital Video Broadcasting Standard EHF Extremely High Frequency IP Internet Protocol LTCC Low Temperature Co-fired Ceramic MCD Multi-Carrier Demodulator MHOMS Modem for High Order Modulation Scheme OBMM On-Board MPEG Multiplexer OBP On-Board Processing OBPC On-Board Processing Controller QPSK Quadri Phase Shift Keying RCS Return Channel Satellite RCST Return Channel Satellite Terminal SCPC Single Carrier Per Channel TDMA Time Division Multiple Access 2 nd Quarter Alcatel Telecommunications Review - 7

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