ATM-Sat: ATM-Based Multimedia Communication via LEO-Satellites

Transkript

1 : ATM-Based Multimedia Communication via LEO-Satellites Projektübersicht DLR Oberpfaffenhofen 1

2 Projektdaten 4 Projektdauer: Juli Juni Projektpartner: h DLR Oberpfaffenhofen, Institut für Kommunikation und Navigation Abteilung Digitale Netze (DN) - Projektleitung h DLR Oberpfaffenhofen, Institut für Kommunikation und Navigation, Abteilung Navigations- und Leitsysteme (NL) h GMD FOKUS Berlin, Competence Center for Advanced Network Technologies and Systems (CATS) h Bosch SatCom GmbH Backnang, Space Communication Systems 4 wird finanziert aus dem Strategiefonds der Helmholtz-Gemeinschaft 2

3 Projektziele 4 will develop the concept and the communication technology for a multimedia satellite system with: h Low Earth Orbit satellites and GEO satellites h intersatellite links h on-board ATM switching h fixed and mobile terminals h reenforced consideration of internet-based services 4 will verify the developed communication technology with a demonstrator 4 will provide support to the German space and communications industry in acquiring the future market of multimedia satellite communication 3

4 System Characteristics LEO satellites intersatellite links dynamic network topology shared medium limited bandwidth propagation delay bit errors LEO satellites ISL ISL R&D system and protocol architecture (DLR, GMD) on-board processing (Bosch) ISL routing scheme (DLR) radio & ATM resource (DLR) management multiple access protocol (DLR) error control (DLR) transmission scheme (DLR) - support all traffic classes! - meet QoS requirements! - optimize bandwidth utilization! fixed, portable, and mobile terminals multiservice scenario Broadband user terminals Broadband core network mobility management and handover (GMD) IP over satellite-atm (GMD, DLR) active intelligent antennas (DLR) 4

5 Systemkonzept eines ISL-basierten breitbandigen LEO Satellitensystems für die Multimediakommunikation ISL sub-network: transport of longdistance traffic Air interface: user access Fixed, portable and mobile terminals Broadband core network Internet Cache GW: connection to terrestrial fixed networks 5

6 Systemkonzept / Anwendungszenarium für das Zielsystem Inter Satellite Link Modem Modem ATM- Switch Sat. Modem Terminals: - for individual use - for user groups - directive antennas, LOS! ISDN ISDN IP ATM MPEG ISDN/ ATM IP/ ATM MPEG /ATM CBR UBR ABR VBR Protocol ATM Conversion Layer / AAL Terminal Sat Modem Satellite Comm. Layers: S-DLC, S-MAC, S-PHY Sat. Modem ATM/ ISDN ATM/ IP ATM Interworking Units Gateway Mobile/Portable ATM Terminal ISDN Internet ATM 6

7 Dienste und Anwendungen (Auswahl) Voice CD quality audio Video conferencing and video telephony Broadcast TV quality video Multimedia applications Web browsing, file transfer, IP over ATM Network interconnection Standard Bit rate Mapping ATM services LD-CELP, ADPCM, SB-ADPCM, PCM kbit/s CBR MPEG-1 audio (MP3) kbit/s CBR MPEG audio FFT 384 kbit/s CBR H.261 p*64 kbit/s, p=1, 2,..., 30 CBR, rt-vbr, nrt-vbr JPEG MJPEG 1,..., 2 (5) Mbit/s 1,..., 2 (10) Mbit/s CBR, nrt-vbr CBR, nrt-vbr MPEG-2 2, 4, 6, to > 20 Mbit/s CBR, rt-vbr, nrt-vbr MPEG-4 64 kbit/s,..., 2 (4) Mbit/s CBR, rt-vbr p*16 kbit/s, p=1, 2,... UBR, UBR with MCR, ABR p*16 kbit/s, p=1, 2,... UBR, UBR with MCR, CBR, nrt-vbr, ABR 7

8 Einige Systemparameter 4 Terminal data rate: uplink: 16 kbit/s, 32 kbit/s,..., 2 Mbit/s downlink: 16 kbit/s up to 32 Mbit/s 4 Satellite switch capacity: 5 Gbit/s - 10 Gbit/s 4 Spotbeams per satellite: Carriers per satellite: Maximum number of carriers per spotbeam: Maximum number of downlink channels (16 kbit/s) per carrier: 2000 Unidirectional downlink channels (16 kbit/s) per satellite: Bidirectional channels (16 kbit/s) per satellite:

9 Satellitenkonstellation Satelliten: 72 (12*6) Orbits: 12 Orbithöhe: 1350 km Orbitperiode: min Inklination:47 Phasung: 25 ISLs: ja Minimale Elevation: Ø Footprint: km 9

10 ATM in fixed and radio networks Fixed Network Wire Multiplexing/Buffering/Scheduler Outgoing link Only one terminal per ATM switch port point-to-point Bandwidth constraint Radio () Network Feedback channel Air interface Uplink Access Control TDMA: slot scheduling Problems: More than one terminal per ATM switch port! Uplink bandwidth constraint shared medium Receiver From other carrier From ISL Satellite ISL Downlink ISL TDMA: scheduling delay hard limitation CDMA: complexity, back-off power control 10

11 Protokollarchitektur Satellite ATM Terminal Application ILMI Satellite Radio Resource and Mobility Management ILMI S-MIB M-UNI SNMP M-UNI SNMP S-AAL AAL-X AAL-5 S-AAL AAL-5 ATM ATM L M E S-LLC Radio DLC S-MAC Radio PHY L M E S-LLC Radio DLC S-MAC Radio PHY Control Plane User Plane Management Plane Control Plane User Plane Management Plane 11

12 MF-TDMA Frame Uplink Frame Structure Frame, 24 ms Frequency Carriers slot: kbit/s useful data rate CTRLPACKET (15 Byte): FULLPACKET (80 Byte): Preamble Header RS Preamble ATM- Header ATM-Payload RS Header Out-Band Signalling - RS(15,11) Code - In-Band Signalling - One ATM-Cell per packet - RS(80,64) Code 12

13 Demonstrator (MAC) Terminal of fixed network Terminal 1 OC3 Ethernet DLC PC (MAC, LLC) Load Generator OC3 OC3 Ethernet OC3 Ethernet Terminal 2 DLC PC (MAC, LLC) Terminal 3 DLC PC (MAC, LLC) Uplink Uplink Downlink Uplink Ethernet PC Wireless Link- Emulation: Packet Errors, Collisions, Delay Uplink Downlink Ethernet Satellite DLC PC (Scheduler) OC3 Ethernet Switch Controller ATM Signalling Workstation Uplink bit rate: 3 Mbit/s Downlink bit rate: up to / more than 32 Mbit/s 13

14 Demonstrator (MAC) Planned Demonstrations (selection) 4 MAC protocol, priority scheduling 4 Connection setup and release, more than one connection per terminal 4 Video (MPEG1, MJPEG) and audio applications with CBR or UBR 4 Web browsing with UBR or UBR with MCR 4 Network interconnection? Planned Experiments and Measurements (selection) 4 Influence of radio channel (cell loss, delay) on end application, performance of error control 4 Efficiency of scheduling algorithm (statistics of slot usage,...) 14

15 Warum aktive intelligente Antennen? Breitbandige Multimediakommunikation über Satellit Hohe Kanalbitrate Koexistenz verschiedener Satellitensysteme im gleichen Frequenzband LEO-Satelliten Richtantenne im Terminal notwendig Mobile Terminals Richtantenne muß schnell schwenkbar sein Entwicklung aktiver intelligenter Antennen 15

16 Zusammenfassung 4 entwickelt eine Systemarchitektur für die ATM-Übertragung über LEO- Satelliten 4 entwickelt die Protokollarchitektur, Fehlersicherung, Medium Access Control (MAC), Ressourcenmanagement, ISL Routing und Verfahren für IP over Satellite-ATM 4 entwickelt und realisiert einen LLC/MAC-Demonstrator für ATM über Satellit (Priority Scheduling, Radio Resource Management) 4 führt End-zu-End Demonstrationen und Performance-Messungen am Demonstrator durch 4 macht Untersuchungen zu aktiven intelligenten Antennen und entwickelt und realisiert dazu auch einen Demonstrator 16

17 Zusätzliche Folien 17

18 R&D Objectives System Requirements System Architecture Protocol Architecture Medium Access Error Control ISL Routing Payload Design Resource Mgmt. Mobility Mgmt. Demonstrator Architecture Resource Mgmt. Switch / OBP Medium Access DLR Antennas IP over Satellite-ATM Terminals DEMONSTRATOR t GMD Bosch TARGET SYSTEM Specify Implement Demonstr. Evaluate Define requirem. Develop Simulate DLR/GMD Evaluate perform. t Specify system DLR GMD BOSCH DLR 18

19 Warum ATM? new broadband satellite networks, partly with ISLs ATM advantages ATM in fixed broadband core networks, LANs ATM in satellite networks for fixed, portable, and mobile communication 19

20 Systemarchitektur Vor- und Nachteile kleiner minimaler Elevationswinkel (ε min ): + große Ausleuchtzone (Footprint) wenig Satelliten erforderlich - mehr Abschattungen - höhere Freiraumdämpfung - höhere Regendämpfung - erhöhter Aufwand bei aktiver intelligenter Terminalantenne (Schwenkbereich) ε min Ausleuchtzone 20

21 ATM-Based ISL Routing start/end satellites satellite orbit intermediate satellites S z S w S x S y multiservice routing scheme integration of UDL/ISL routing integration of routing with CAC combined routing/dimensioning problem UDL Routing ISL Routing UDL Routing 21

22 Protokollarchitektur - DLC Layer 4 DLC Layer unterscheidet die verschiedenen ATM-Verbindungen anhand der VPI/VCI-Werte der ATM-Zellen 4 Beim Verbindungsaufbau müssen dem DLC Layer die VPI/VCI-Werte mit den Verkehrsparametern (ATM-Dienstkategorie, PCR,...) vom UNI (über LME) mitgeteilt werden 4 DLC Layer muß bei der CAC beteiligt sein (über LME) 4 Beispiele: h CBR-Dienst: feste periodische Allokierung von Zeitschlitzen während der gesamten Verbindung entsprechend der PCR h UBR-Dienst: dynamische Allokierung von Zeitschlitzen entsprechend dem Verkehrsaufkommen (round robin) h UBR-Dienst mit MCR: feste Allokierung von Zeitschlitzen entsprechend der MCR, dynamische Allokierung weiterer Zeitschlitze entsprechend dem Verkehrsaufkommen 22

23 Fehlersicherung ARQ, FEC FEC Terminal AAL ATM S-LLC S-MAC S-PHY ATM Service Category CBR, rt-vbr nrt-vbr ABR UBR Error Control Method (adaptive) FEC limited ARQ, (adaptive) FEC ARQ, (adaptive) FEC, hybrid ARQ not mandatory, ARQ, (adaptive) FEC Satellite ATM S-LLC S-MAC S-PHY ARQ, FEC FEC Error-prone Satellite- Channel Normalized power / db Time /s channel modelling, rain attenuation 23