TELIT GROUP Industries for Telecommunications 1 27th February 2001 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 TELIT MOBILE TERMINALS Giovanni De Maio Telit Mobile Terminals S.p.A. Project Manager - System Engineering Satellite User Terminal Division Via Vitorchiano, 81 - Rome

TELIT GROUP Industries for Telecommunications 2 Globalstar System Overview

TELIT GROUP Industries for Telecommunications 3 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 automatically from the terrestrial to the satellite mode. The system is designed in order to maximise coverage in the temperate areas. Globalstar System Overview Globalstar service aspects

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

TELIT GROUP Industries for Telecommunications 5 Globalstar constellation 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 48 LEO satellites: User terminals can be served by a satellite 10 to 15 minutes out of each orbit. Globalstar System Overview Space Segment

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

TELIT GROUP Industries for Telecommunications 7 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 At least one satellite always visible for LATITUDE<70° Globalstar System Overview Space Segment

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

TELIT GROUP Industries for Telecommunications 9 Space Segment Frequency channels Globalstar System Overview

TELIT GROUP Industries for Telecommunications 1010 Space Segment Forward and Reverse User links channels or Sub-Beams S-Band Forward User Link channels (Sub- Beams) L-Band Reverse User Link channels (Sub-Beams) Globalstar System Overview

TELIT GROUP Industries for Telecommunications1 Space Segment Sub-Beams to Gateways Assignment Overlapping Beams will transmit Sub-Beams for both Gateways Globalstar System Overview

TELIT GROUP Industries for Telecommunications 1212 Space Segment Globalstar System Overview PILOT: unmodulated DS SS signal transmitted by the Gateway (employed to acquire the timing, as phase reference for demodulation and to handoff) SYNC: channel carrying a repeating message for terminal synchronization PAGING: u provides system access information for registering UT’s u lets a phone know that a call is coming in or that there is a message in voice mail u for SMS u to reply to a UT trying to place a call, for handoff messaging when not in a call 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) ACCESS: slotted random access channel for call originations, responses to pages and registrations Globalstar Air Interface Channels

TELIT GROUP Industries for Telecommunications 1313 Space Segment Globalstar System Overview Example of a Forward CDMA Channel 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

TELIT GROUP Industries for Telecommunications 1414 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.

TELIT GROUP Industries for Telecommunications 1515 Globalstar System Overview Space Segment Diversity Operation 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) Spatial diversity in the forward link is illustrated: combining is performed on up to three received signal replicas

TELIT GROUP Industries for Telecommunications 1616 Space Segment Hard Handoff: Intrabeam Handoff (change of frequency) Globalstar Handoffs Globalstar System Overview

TELIT GROUP Industries for Telecommunications 1717 Globalstar System Overview Ground Segment GOCC: Ground Operations Control Center SOCC: Space Operations Control Center SPCC: Service Provider Control Center Components TT&C: Tracking, Telemetry and Command GDN: Globalstar Data Network GCC: Globalstar Control Center (incorporates GOCC, SOCC and GBO into a single facility) GBO: Globalstar Business Office (for financial and administrative aspects:business arrangements with SP’s, billing, marketing and sales efforts

TELIT GROUP Industries for Telecommunications 1818 Ground Segment RF SUBSYSTEM IS-41 MSC VLR BSC CDMA SUBSYSTEM GSM MSC VLR GATEWAY GSM PLMN HLR GSM GMSC VLR A Interface PSTN PLMN LOCAL GSM MSC/VLR Gateway - PLMN Interconnection Globalstar System Overview

TELIT GROUP Industries for Telecommunications 1919 User Segment 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 Globalstar User Terminals Status: Telit SAT 550 Globalstar System Overview

TELIT GROUP Industries for Telecommunications 2020 Globalstar User Terminals Status: Telit SAT 650 User Segment Front shell Controller board Shield Radio board Shield Rear shell Globalstar System Overview

TELIT GROUP Industries for Telecommunications 2121 GS User-to-GS User Operation 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 Call Processing Globalstar System Overview

TELIT GROUP Industries for Telecommunications2 Call Processing Simplified Call Procedure A User tries to place a call through the Globalstar Satellite service: if the called party is a wireline or terrestrial cellular-based end 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 Globalstar System Overview A B B C C

TELIT GROUP Industries for Telecommunications G S-PCS: The Next Step

TELIT GROUP Industries for Telecommunications 2424 Wireless Evolution through the Generations series 1G 2G 3G Analogue voice (AMPS- Advanced Mobile Phone Standard, TACS-Total Access Communications System,... ) Digital voice, low data rate applications [GSM, IS-54 (TDMA), IS-95 (CDMA), GLOBALSTAR, IRIDIUM…] UMTS/IMT 2000 Global Standard for wireless multimedia 3G S-PCS: The Next Step

TELIT GROUP Industries for Telecommunications 2525 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 by the 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. IMT 2000 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.) 3G S-PCS: The Next Step

TELIT GROUP Industries for Telecommunications G S-PCS: The Next Step Satellite Air interface selection - ITU Process 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) Formerly TTA- SAT. (SRI-C) (ESA RTT) Commonalities with ETSI UTRA TDD. Attractive for regional systems (HEO/GEO). (SRI-B) Harmonization on going

TELIT GROUP Industries for Telecommunications 2727 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. First set of ETSI Technical Specs approved (1/2) 3G S-PCS: The Next Step

TELIT GROUP Industries for Telecommunications 2828 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 ) Part 2: Multiplexing and channel coding (S-UMTS-A ) Part 3: Spreading and modulation (S-UMTS-A ) Part 4: Physical layer procedures (S-UMTS-A ) 3G S-PCS: The Next Step

TELIT GROUP Industries for Telecommunications 2929 S-UMTS Air Interface transport and physical channels The mapping of transport channels onto physical channels is a fundamental function performed by the physical layer 3G S-PCS: The Next Step

TELIT GROUP Industries for Telecommunications 3030 Worldwide Frequency Bands ERC (European Radiocommunications Committee) assignments to MSS: – 2 x 30 MHz ( MHz and MHz) – 15 MHz available from 2000 ( MHz and MHz) – 30 MHz available from 2005 ( MHz and MHz) – 15 MHz assigned TDMA systems (S-PCS) ( MHz and MHz) 2X30 MHz in S- Band allocated to MSS, adjacent to spectrum allocation for terrestrial systems 3G S-PCS: The Next Step

TELIT GROUP Industries for Telecommunications 3131 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

TELIT GROUP Industries for Telecommunications 3232 From 3GPP 3G TS : UMTS Service aspects, Services and Service Capabilities 3G S-PCS: The Next Step

TELIT GROUP Industries for Telecommunications3 Again from 3GPP 3G TS G S-PCS: The Next Step

TELIT GROUP Industries for Telecommunications 3434 UMTS QoS Classes (1/2) 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-bearer mapping, 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. 3G S-PCS: The Next Step

TELIT GROUP Industries for Telecommunications 3535 UMTS QoS Classes (2/2) Attributes for UMTS Bearer Services 3G S-PCS: The Next Step

TELIT GROUP Industries for Telecommunications 3636 The “Satellite Access Network” 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. Iub ? Iur ? 3G S-PCS: The Next Step

TELIT GROUP Industries for Telecommunications 3737 S-UMTS Terminal : envisaged architecture 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. The Control Processor manages the exchange of data/addressing information between the DSP and the ASIC 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. 3G S-PCS: The Next Step