BTnodes. Design and Deployment of Wireless Networked Embedded Systems. Jan Beutel. Computer Engineering and Networks Lab, ETH Zurich.

Transcription

1 BTnodes Design and Deployment of Wireless Networked Embedded Systems Jan Beutel Computer Engineering and Networks Lab, ETH Zurich 8-Nov-05

2 Wireless Sensor Networks Visions Ubiquitous Vision Smart Dust Directed Diffusion COTS Dust Scale Free Networks Wireless Overlay PicoRadio Paintable Computing Terminodes Applications Argo Military Surveillance James Reserve Shooter Localization Sensor Webs Duck Island ZebraNet 2

3 Wireless Sensor Networks Visions Ubiquitous Vision Smart Dust Directed Diffusion COTS Dust Scale Free Networks Wireless Overlay PicoRadio Paintable Computing WSN Community Terminodes Applications Argo Sensor Webs Military Surveillance Duck Island James Reserve Prototypes, Experiments and Research Demos ZebraNet Shooter Localization 3

4 Wireless Sensor Networks Visions Ubiquitous Vision Smart Dust Directed Diffusion COTS Dust Scale Free Networks Wireless PicoRadio Paintable Terminodes Other Overlay Computing WSN Community People Applications Argo Production Applications Sensor Webs Military Surveillance Duck Island James Reserve Prototypes, Experiments and Research Demos ZebraNet Shooter Localization 4

5 Argo Global Ocean Observation Strategy Global array of temperature/salinity profiling floats Satellite data relay to data centers on shore Operational since 2000 Developed and maintained mainly by oceanographers 5

6 Anti-Submarine Surveillance Distributed acoustic monitoring and surveillance Advanced signal processing Mostly wireline and analog Fixed installations and mobile units Military development since the cold war 6

7 Globally Networked Weather Stations 7

8 Wireless Sensor Networks Visions Ubiquitous Vision Smart Dust Directed Diffusion COTS Dust Scale Free Networks Wireless Overlay PicoRadio Paintable Computing Terminodes Applications Argo Military Surveillance James Reserve Shooter Localization Sensor Webs Duck Island ZebraNet 8

9 The WSN Evolution I have Motes. Aka I write simulation papers. People/Papers I have downloaded the TOS installer. I checked out a demo example. I changed a line of code. I use CVS and contribute. 9

10 WSN Development Reality It is hard to deploy anywhere beyond nodes today. Coordinated methods and tools are missing today. 10

11 Outline BTnode platform for fast-prototyping Metrics and comparison of existing platforms Design of hard- and software based on standardized interfaces and event driven interaction Concept/Theory Design and Development Prototype and Pilot Launch and Ramp Production Service and Support Bluetooth multihop networking Tree topology control mechanisms Field Experiments XTC mesh networking Deployment-support network Operational concept Feasibility study, experiments 11

12 Outline BTnode platform for fast-prototyping Metrics and comparison of existing platforms Design of hard- and software based on standardized interfaces and event driven interaction Concept/Theory Design and Development Prototype and Pilot Launch and Ramp Production Service and Support Bluetooth multihop networking Tree topology control mechanisms Field Experiments XTC mesh networking Deployment-support network Operational concept Feasibility study, experiments 12

13 Wireless Sensor Network Systems Today 13

14 Metrics of WSN Platforms Large application domain No unified one-size-fits-all solution [Römer2004] Applications Good platform? Suitable solution? Optimum match? Requirement? Platform Metrics Comparisons Automated tools common in EDA community E.g. semi-automatic design space exploration [Künzli2005,Anliker2004] Current WSN community approach Device characterization, e.g. Mote family [Polastre2005,Shnayder2004] Tiered architectures [Estrin2003], WSN device classes [Hill2004] 14

15 State-of-the-Art Platforms System Core Mica2 Mica2Dot Tmote Sky Lack of Flexibility Imote 15

16 State-of-the-Art Platforms Radio Systems 2 strategies Packet oriented Bitstream oriented Event-based Interaction Mica2 Mica2Dot Tmote Sky Real-time processing Imote 16

17 State-of-the-Art Platform Comparison Is there room for another platform? Mica2 Mica2Dot Tmote Sky Imote System Core Balanced computing resources? Radio Systems Multipurpose radio? 17

18 Outline BTnode platform for fast-prototyping Metrics and comparison of existing platforms Design of hard- and software based on standardized interfaces and event driven interaction Concept/Theory Design and Development Prototype and Pilot Launch and Ramp Production Service and Support Bluetooth multihop networking Tree topology control mechanisms Field Experiments XTC mesh networking Deployment-support network Operational concept Feasibility study, experiments 18

19 The BTnode Platform Communication Computation IO/Peripherals Prototype 2 nd Generation 3 rd Generation 19

20 BTnode rev3 Architecture Details System core Atmel ATmega kb SRAM Generic IO/Peripherals Switchable power supplies Dual radio system Bluetooth radio 2.4 GHz Zeevo ZV4002 Low-power radio MHz ISM Chipcon CC mm 32.5 mm 20

21 State-of-the-Art Platforms Comparison Mica2 Mica2Dot Tmote Sky Imote BTnode rev3 System Core Radio Systems 21

22 BTnut System Software Versatile and flexible fast-prototyping Lightweight operating system support in plain C Linux-to-AVR embedded emulation Demo applications and tutorial compile emulate simulate upload Built on top of multi-threaded Nut/OS framework Non-preemptive, cooperative multi-threading Events, timers Priorities for threads Dynamic heap allocation Interrupt driven streaming I/O 22

23 BTnode Platform Success Industrial technology transfer Commercialization with ETH spin-off Art of Technology Commercial replicas resulting from open source policy BTnodes in Education Different labs and demos Graduate lab in embedded systems (120 participants) successfully completed student projects BTnode dev kit 500 BTnodes in Research Domains 25+ wearable and ubiquitous computing applications and demos Wireless (sensor) network research 40+ scientific publications based on or related to BTnodes 50 ma Slave sniff 45 Master sniff Slave active Master active Standby samples

24 Outline BTnode platform for fast-prototyping Metrics and comparison of existing platforms Design of hard- and software based on standardized interfaces and event driven interaction Concept/Theory Design and Development Prototype and Pilot Launch and Ramp Production Service and Support Bluetooth multihop networking Tree topology control mechanisms Field Experiments XTC mesh networking Deployment-support network Operational concept Feasibility study, experiments 24

25 Deployment of Network Services Example: Location Management Finding position based on radionavigation Robust network-based trilateration Service deployment functions Re-programming Supervision, control and monitoring Measurements, benchmarking Requirement Robust connectivity Reliable data link layer 25

26 Bluetooth Multihop Network Topologies Constructing ad hoc network topologies Large networks, many devices All devices connected Transparent multihop transport Scatternet formation algorithms BlueMesh [Petrioli2002], BlueStars [Petrioli2003], BlueRings [Foo2002], BlueTrees [Zaruba2001], mesh topologies [Guerin2003] Single-hop connectivity [Law2003] Complexity analysis [Law2003,Vergetis2003], comparative study [Basagni2004] Mostly static, no (large-scale) implementation reports 26

27 Bluetooth Multihop Network Topologies XHOP Initial experiments Time-multiplexed, dumbbell-like connections TreeNet Large, connected topologies Simple, top-down tree-building DSNtrees Distributed tree topology formation Random connection points Streaming data 27

28 Simple Scatternet Tree Construction Link layer connectivity Random search and connect loop { while (my_slaves < max_degree) do found_nodes = inquiry(); forall nodes in found_nodes do connect(); } } Distributed coordination Inquiry() and connect() operations can exhibit long delays No a priori guarantee for success Serialization of parallel processes 28

29 Making a Seven Line Algorithm Work loop { while (my_slaves < max_degree) do found_nodes = inquiry(); forall nodes in found_nodes do Seven connect(); lines } } #define HEX2BYTE(c) ((u_char)(((c)<='9')? (c)-'0' : tolower(c) - 'a' + 10)) typedef struct _jaws_stack { FILE *uart_terminal; HANDLE table_changed_event; bt_addr_t my_addr; struct btstack* bt_stack; bt_l2cap_stack_t *l2cap_stack; } jaws_stack_t; jaws_stack_t* _jaws_stack; //int foo attribute ((section (".noinit"))); //int foo2 attribute ((section (".eeprom"))); void bt_print_bt_addr(bt_addr_t addr) DEBUGT("%.2x:%.2x:%.2x:%.2x:%.2x:%.2x", addr[5], addr[4], addr[3], addr[2], addr[1], addr[0]); const char *bt_addr_to_string( char *buf, bt_addr_t addr) sprintf_p( buf, PSTR("%.2x:%.2x:%.2x:%.2x:%.2x:%.2x"), addr[5], addr[4], addr[3], addr[2], addr[1], addr[0]); return buf; } u_char* string_to_bt_addr(u_char* str, u_char* addr) { char i; u_char *strp = str; // skip whitespace while(*strp 2000 == ' ') lines strp++; for(i = BD_ADDR_LEN-1; i >= 0; i--){ if(isxdigit(strp[0]) && isxdigit(strp[1])){ addr[(u_char) i] = HEX2BYTE(strp[0]) << 4 HEX2BYTE(strp[1]); strp+=2; }else{ break; } // skip ':' if(i > 0){ if(*strp == ':') strp++; else break; } } u_char get_uart_errors(file* stream){ u_long parameter; u_char errors; // check driver status _ioctl(_fileno(stream), UART_GETSTATUS, &parameter); if (parameter & UART_ERRORS) { errors = (u_char) (parameter & UART_ERRORS); // set error flags back to normal parameter = UART_ERRORS; _ioctl(_fileno(stream), UART_SETSTATUS, &parameter); + Adaptation to devices Root lockup, cycle elimination + Error handling Deadlocks, timeouts + Robustness, performance Greedy behavior, heuristics ~87 kbyte + Application support Basic OS functions Debugging, visualization, monitoring Stepwise testing + deployment 29

30 DSNtrees Field Experiments Deployment using 70+ nodes on an office floor Largest connected Bluetooth Scatternet 30

31 XTC Bluetooth Mesh Networking Bluetooth Mesh Networking based on BTnode Spec [Wattenhofer2004] Paper-grade algorithm to robust implementation Experiments, measurements and evaluation are ongoing 31

32 Outline BTnode platform for fast-prototyping Metrics and comparison of existing platforms Design of hard- and software based on standardized interfaces and event driven interaction Concept/Theory Design and Development Prototype and Pilot Launch and Ramp Production Service and Support Bluetooth multihop networking Tree topology control mechanisms Field Experiments XTC mesh networking Deployment-support network Operational concept Feasibility study, experiments 32

33 WSN Development Reality It is hard to deploy anywhere beyond nodes today. Coordinated methods and tools are missing today. 33

34 Today's WSN Design and Development Simulation TOSSIM [Levis2003] PowerTOSSIM [Shnayder2004] Avrora [Titzer2005] Specialized simulation tools for WSN applications Scale Virtualization and Emulation EmStar [Ganesan2004] BEE [Chang2003,Kuusilinna2003] Fast-prototyping in a controlled environment Test Grids motelab [Werner-Allen2005] Emstar arrays [Cerpa03/04] Kansei [Dutta2005] Reality Closing in on the real experience Figure abridged from D. Estrin/J. Elson 34

35 Today's WSN Design and Development Simulation Scale TOSSIM [Levis2003] PowerTOSSIM [Shnayder2004] Avrora [Titzer2005] Virtualization and Emulation EmStar [Ganesan2004] BEE [Chang2003,Kuusilinna2003] Test Grids motelab [Werner-Allen2005] Emstar arrays [Cerpa03/04] Kansei [Dutta2005] Reality Deployment In-network reprogramming [Levis2004,Hui2004] Calibration and Verification [Szewczyk2004] Trial-and-error [Mainwaring2004, Hemingway2004,Cerpa2001] Dependence on infrastructure [Szewczyk2004] Figure abridged from D. Estrin/J. Elson 35

36 From Proof-of-concept to Real-world WSNs Traditional test grid Wired Immobile Not scalable In-network tools Unreliable Self-organizing backbone network with deployment-support services Deployment-Support Network 36

37 Next-Generation Deployment-Support Developer Workstation Deployment-Support Network Temporary, minimal invasive Virtual connections to nodes Reliable, wireless, scalable Target Sensor Network 37

38 JAWS Application Partitioning JAWS Application Topology Control Connection Management Data Transport Caching Node Management Codesize 100 kb Target Adapter Target Control Programming Logging 4 kb WSN Target Application Monitor Threads/IRQs High level context 2 kb 38

39 JAWS Application Example Test Setup: 20+ nodes Event Tracing Context switches Interrupts Next steps: Distributed, time-synched, tracing 39

40 Acknowledgements BTnode Core Team Oliver Kasten, Matthias Ringwald, Kay Römer, Friedemann Mattern Philipp Blum, Matthias Dyer, Kevin Martin, Lennart Meier, Luca Negri, Martin Hinz, Lothar Thiele MICS Algorithms Collaboration Regina O Dell-Bischoff, Fabian Kuhn, Aaron Zollinger, Roger Wattenhofer Related publications L. Negri, J. Beutel and M. Dyer. The Power Consumption of Bluetooth Scatternets. CCNC J. Beutel, M. Dyer, L. Meier, and L. Thiele. Scalable topology control for deployment-sensor networks. IPSN J. Beutel. Robust Topology Formation using BTnodes. Computer Communications J. Beutel, M. Dyer, M. Hinz, L. Meier, M. Ringwald. Next-Generation Prototyping of Sensor Networks. SenSys J. Beutel, O. Kasten, F. Mattern, K. Römer, F. Siegemund, and L. Thiele. Prototyping wireless sensor network applications with BTnodes. EWSN J. Beutel, O. Kasten and M. Ringwald. BTnodes - A Distributed Platform for Sensor Nodes. SenSys

41 To probe further 41