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27th February 2001

TELIT MOBILE TERMINALS. Satellite Personal Communications Systems (S-PCS): the Globalstar System and evolutionary paths towards 3G. SCHOOL ON DIGITAL AND MULTIMEDIA COMMUNICATIONS USING TERRESTRIAL AND SATELLITE RADIO LINKS. 27th February 2001. Giovanni De Maio Telit Mobile Terminals S.p.A.

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27th February 2001

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  1. TELIT MOBILE TERMINALS Satellite Personal Communications Systems (S-PCS): the Globalstar System and evolutionary paths towards 3G SCHOOL ON DIGITAL AND MULTIMEDIA COMMUNICATIONS USING TERRESTRIAL AND SATELLITE RADIO LINKS 27th February 2001 Giovanni De Maio Telit Mobile Terminals S.p.A. Project Manager - System Engineering Satellite User Terminal Division Via Vitorchiano, 81 - Rome giovanni.demaio@telital.com

  2. Globalstar System Overview

  3. Globalstar service aspects Globalstar is a system that provide digital telephony with a global coverage, by means of a satellite constellation working in a Low Earth Orbit (LEO). Globalstar allows access to the terrestrial networks, both fixed and mobile, interworking with them in a complementary way. In areas not covered by the terrestrial networks, the Globalstar Terminal can be set to switch automaticallyfrom the terrestrial to the satellite mode. The system is designed in order to maximise coverage in the temperate areas. Globalstar System Overview

  4. Space Segment User Segment Mobile Portable Fixed GBO SOCC Ground Segment Gateway GDN GOCC Terrestrial Network PLMN/PSTN Globalstar System Architecture Globalstar System Overview GOCC: Ground Operations Control Center SOCC: Space Operations Control Center GDN: Globalstar Data Network GBO: Globalstar Business Office

  5. 48 LEO satellites: At least 7.5 years life time Weight: 450 Kg 1100 Watts against 2000 circuits Distance 1414 Km at 52° 8 orbital planes e 6 equally spaced satellites per orbit Circular orbit period 113 minutes User terminals can be served by a satellite 10 to 15 minutes out of each orbit. Space Segment Globalstar constellation Globalstar System Overview

  6. Space Segment Earth Surface Coverage Globalstar System Overview The system is designed in order to maximise coverage in the temperate areas.

  7. Space Segment Multiple Coverage(48 SATELLITES; 10° ELEVATION) • At LATITUDE 40°: • At least 4 satellites for 38% of time • At least 3 satellites for 87% of time • At least 2 satellites always visible Globalstar System Overview At least one satellite always visible for LATITUDE<70°

  8. Space Segment User and feeder links immagini Globalstar System Overview immagini Satellites are of the non regenerative type: they simply perform a transparent relay of the signals in both Forward and Reverse links

  9. Space Segment Frequency channels Globalstar System Overview

  10. 1 6 1 0 . 0 M H z 1 6 2 6 . 5 M H z 1 6 1 1 . 9 6 0 M H z 1 6 1 4 . 4 2 0 M H z 1 6 1 6 . 8 8 0 M H z 1 6 1 9 . 3 4 0 M H z 1 6 2 1 . 8 0 0 M H z 1 6 2 4 . 2 6 0 M H z 1 6 1 0 . 7 3 0 M H z 1 6 1 3 . 1 9 0 M H z 1 6 1 5 . 6 5 0 M H z 1 6 1 8 . 1 1 0 M H z 1 6 2 0 . 5 7 0 M H z 1 6 2 3 . 0 3 0 M H z 1 6 2 5 . 4 9 0 M H z 1 0 1 0 k H z 7 3 0 k H z 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 1 3 1 . 2 3 M H z 1 . 2 3 M H z 1 . 2 3 M H z 1 . 2 3 M H z 1 . 2 3 M H z 1 . 2 3 M H z 1 . 2 3 M H z 1 6 . 5 M H z F i l e : L - B a n d 2 4 8 3 . 5 M H z 2 5 0 0 . 0 M H z 2 4 8 5 . 6 2 0 M H z 2 4 8 8 . 0 8 0 M H z 2 4 9 0 . 5 4 0 M H z 2 4 9 3 . 0 0 0 M H z 2 4 9 5 . 4 6 0 M H z 2 4 9 7 . 9 2 0 M H z 2 4 8 4 . 3 9 0 M H z 2 4 8 6 . 8 5 0 M H z 2 4 8 9 . 3 1 0 M H z 2 4 9 1 . 7 7 0 M H z 2 4 9 4 . 2 3 0 M H z 2 4 9 6 . 6 9 0 M H z 2 4 9 9 . 1 5 0 M H z 8 5 0 k H z 8 9 0 k H z 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 1 3 1 . 2 3 M H z 1 . 2 3 M H z 1 . 2 3 M H z 1 . 2 3 M H z 1 . 2 3 M H z 1 . 2 3 M H z 1 . 2 3 M H z 1 6 . 5 M H z F i l e : S - B a n d Space Segment Forward and Reverse User links channels or Sub-Beams L-Band Reverse User Link channels (Sub-Beams) Globalstar System Overview S-Band Forward User Link channels (Sub-Beams)

  11. Sub-Beams to Gateways Assignment Space Segment Globalstar System Overview Overlapping Beams will transmit Sub-Beams for both Gateways

  12. PAGING: • provides system access information for registering UT’s • lets a phone know that a call is coming in or that there is a message in voice mail • for SMS • to reply to a UT trying to place a call, for handoff messaging when not in a call Space Segment Globalstar Air Interface Channels Globalstar System Overview ACCESS: slotted random access channel for call originations, responses to pages and registrations PILOT: unmodulated DS SS signal transmitted by the Gateway (employed to acquire the timing, as phase reference for demodulation and to handoff) TRAFFIC: communication path between a UT and a Gateway, which implies a Forward and a Reverse Traffic Channel pair; for voice, data, signaling (when in a call) SYNC: channel carrying a repeating message for terminal synchronization

  13. Space Segment Example of a Forward CDMA Channel Globalstar System Overview The above example shows a particular assignment of the overall 128 channels (codes) within a 1.23 MHz Forward Channel to Pilot, Sync, Paging and Traffic functionalities

  14. Space Segment Acquisition Search Space Globalstar System Overview The acquisition process consists of a research of the pilot signal in a three dimensional search space: its dimensions are PN Code, PN Timing and Frequency Doppler Shift. Note that the Frequency Doppler Shift is actually a quite minor issue for acquisition in a terrestrial environment (e.g. IS-95). Less acquisition times could be achieved in the Warm Start case by exploiting information acquired during the previous start up.

  15. Space Segment Diversity Operation Globalstar System Overview Spatial diversity in the forward link is illustrated: combining is performed on up to three received signal replicas Diversity operation provides significant advantages in both forward and reverse link transmission (combining is carried out by the user terminal and by the Gateway, respectively)

  16. Globalstar Handoffs Space Segment Globalstar System Overview Hard Handoff: Intrabeam Handoff (change of frequency)

  17. Ground Segment Components TT&C: Tracking, Telemetry and Command GDN: Globalstar Data Network GCC: Globalstar Control Center (incorporates GOCC, SOCC and GBO into a single facility) Globalstar System Overview GOCC: Ground Operations Control Center SOCC: Space Operations Control Center SPCC: Service Provider Control Center GBO: Globalstar Business Office (for financial and administrative aspects:business arrangements with SP’s, billing, marketing and sales efforts

  18. PSTN GATEWAY IS-41 MSC VLR LOCAL GSM MSC/VLR CDMA SUBSYSTEM RF SUBSYSTEM GSM MSC VLR BSC PSTN A Interface PLMN GSM PLMN GSM GMSC VLR HLR Ground Segment Gateway - PLMN Interconnection Globalstar System Overview

  19. Main Characteristics: • GSM phase II/Globalstar Compliant • Voice/fax/data/SMS/SS GSM/GLB* Services • Position Location (up to 300 m)* • Automatic/manual Mode Select • Standard Battery 1600 mAh • Overall Weight 415 gr. • Overall Dimensions 21x6x4 cm • Stand-by and talk time in G* [2h - 7h] • Stand-by and talk time in GSM [4h - 83h*] • Graphic Display 4x12 characters + icons • Accessories: • Car Kit, Marine Kit, Home Kit • Data Terminal Adapter • Leather case • Cigarette Lighter Charger (12 Volt) • Desk Top Charger • Solar Charger • * if supported by the network User Segment Globalstar User Terminals Status: Telit SAT 550 Globalstar System Overview

  20. User Segment Globalstar User Terminals Status: Telit SAT 650 Shield Radio board Shield Controller board Front shell Globalstar System Overview Rear shell

  21. GS User-to-GS User Operation Call Processing Globalstar System Overview In this case satellites in view offer, as usual, bent-pipe relays between users and relevant Gateways; whilst the Gateway-to-Gateway connection relies onto the PSTN backbone

  22. C C A A B B Simplified Call Procedure Call Processing Globalstar System Overview User tries to place a call through the Globalstar Satellite service: if the called party is a wireline or terrestrial cellular-basedend user ( ), the call is routed through either the PSTN or PLMN if the called party is a satellite-based end user ( ) the call is routed back through the Gateway up to the Globalstar Satellite and down to the user

  23. 3G S-PCS: The Next Step

  24. Wireless Evolution through the Generations series 3G UMTS/IMT 2000 Global Standard for wireless multimedia Digital voice, low data rate applications [GSM, IS-54 (TDMA), IS-95 (CDMA), GLOBALSTAR, IRIDIUM…] 2G 3G S-PCS: The Next Step 1G Analogue voice (AMPS- Advanced Mobile Phone Standard, TACS-Total Access Communications System,... )

  25. IMT 2000 International Mobile Telecommunications-2000 (IMT-2000) are third generation mobile systems which are scheduled to start service around the year 2000 subject to market considerations. They will provide access, by means of one or more radio links, to a wide range of telecommunications services supported bythe fixed telecommunication networks (e.g. PSTN/ISDN/IP), and to other services which are specific to mobile users A range of mobile terminal types is encompassed, linking to terrestrial and/or satellite based networks, and the terminals may be designed for mobile or fixed use As a strategic priority of ITU, IMT-2000 provides framework for worldwide wireless access by linking the diverse system of terrestrial and/or satellite based networks. 3G S-PCS: The Next Step IMT is a result of the collaboration of many entities, inside the ITU (ITU-R Radiocommunication Sector and ITU-T Telecommunication Standardization Sector ), and outside the ITU (3GPP, 3GPP2, etc.)

  26. Satellite Air interface selection - ITU Process (ESA RTT) Commonalities with ETSI UTRA TDD. Attractive for regional systems (HEO/GEO). (SRI-B) Formerly TTA- SAT. (SRI-C) Harmonization on going Satellite Wide Band CDMA (ESA RTT- Radio Transmission Technology). Adaptation of UMTS UTRA W-CDMA to the satellite environment. Suited for global systems(LEO/MEO).(SRI-A) 3G S-PCS: The Next Step

  27. First set of ETSI Technical Specs approved (1/2) S-UMTS stands for the Satellite component of the Universal Mobile Telecommunication System. S-UMTS systems will complement the terrestrial UMTS (T-UMTS) and inter-work with other IMT-2000 family members through the UMTS core network. S-UMTS will be used to deliver 3rd generation mobile satellite services (MSS) utilizing either low (LEO) or medium (MEO) earth orbiting, or geostationary (GEO) satellite(s). S-UMTS systems are based on terrestrial 3GPP specifications and will support access to GSM/UMTS core networks. Due to the differences between terrestrial and satellite channel characteristics, some modifications to the terrestrial UMTS (T-UMTS) standards are necessary. Some specifications are directly applicable, whereas others are applicable with modifications. Similarly, some T-UMTS specifications do not apply, whilst some S-UMTS specifications have no corresponding T-UMTS specification. 3G S-PCS: The Next Step

  28. First set of ETSI Technical Specs approved (2/2) Satellite Component of UMTS/IMT 2000; A-family; Part 1: Physical channels and mapping of transport channels into physical channels (S-UMTS-A 25.211) Part 2: Multiplexing and channel coding (S-UMTS-A 25.212) Part 3: Spreading and modulation (S-UMTS-A 25.213) Part 4: Physical layer procedures (S-UMTS-A 25.214) 3G S-PCS: The Next Step

  29. S-UMTS Air Interface transport and physical channels 3G S-PCS: The Next Step The mapping of transport channels onto physical channels is a fundamental function performed by the physical layer

  30. Worldwide Frequency Bands 2X30 MHz in S-Band allocated to MSS, adjacent to spectrum allocation for terrestrial systems 3G S-PCS: The Next Step ERC (European Radiocommunications Committee) assignments to MSS: – 2 x 30 MHz (1980 - 2010 MHz and 2170 - 2200 MHz) – 15 MHz available from 2000 (1995 - 2010 MHz and 2185 - 2200 MHz) – 30 MHz available from 2005 (1980 - 2010 MHz and 2170 - 2200 MHz) – 15 MHz assigned TDMA systems (S-PCS) (1995 - 2010 MHz and 2185 -2200 MHz)

  31. Spectrum Needs More bandwidth requested Terrestrial PCS are competing for spectrum allocation WRC2000 (2000 World Radiocommunications Conference) postponed a decision on satellite phone frequencies until 2003, which means that before 2003 a viable satellite consortium needs to be established or else the already allocated spectrum will be lost and available in favour of T-UMTS 3G S-PCS: The Next Step

  32. From 3GPP 3G TS 22.105: UMTS Service aspects, Services and Service Capabilities 3G S-PCS: The Next Step

  33. Again from 3GPP 3G TS 22.105 3G S-PCS: The Next Step

  34. UMTS QoS Classes (1/2) 3G S-PCS: The Next Step Differently from systems belonging to the previous generations, UMTS allows to enjoy the use of bearers, defined by means of bearer service attributes, and not of end-services/applications directly. To aid the application-to-bearermapping, QoS classes for homogeneous end-services have been devised, which are themselves service attributes, characterized by a set of specific service attributes, as from the following viewgraph.

  35. UMTS QoS Classes (2/2) Attributes for UMTS Bearer Services 3G S-PCS: The Next Step

  36. Iub ? Iur ? The “Satellite Access Network” 3G S-PCS: The Next Step The access network infrastructure for the S-UMTS is here envisaged with minimal differences compared to the terrestrial 3G infrastructure. The satellite should play the role of the T-UMTS Node B (Base Station) but it’s to be deepened whether the same terrestrial Iur and Iub interfaces could be employed, which have been devised for T-UMTS between RNC’s and between RNC and Node B, respectively.

  37. S-UMTS Terminal : envisaged architecture The Control Processor manages the exchange of data/addressing information between the DSP and the ASIC A digital predistortion in the TX path is envisaged, performed by the loop “DSP-Up conversion path-Antenna set-Feedback”. The same feedback line, shown in figure, is used to perform a dinamic adjustment, to improve the linearity of the receiving section. 3G S-PCS: The Next Step The core of the system is the DSP, responsible of most of the baseband processing; the support of dedicated ASICs for particular heavy computational operations like rake-decoding/Interference mitigation can be necessary depending on DSP computational power. In this last case, a dedicated bus between the DSP and the ASIC could also be needed, or the ASIC should directly communicate with the AD/DA converters and then with the DSP.

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