The Implementation of IPv6 Wireless Sensor Network Nodes University of Electronic Science and Technology of China UESTC

Sponsored by China Next Generation Internet (CNGI)

Our Goals Architecture and key technologies of Wireless sensor network node IPv6 support Low power MCU Work mode 10mW,sleep mode 2mW Node energy consumption: Transmission 50mW, Receive 25mW Sleep 15mW Develop 30 nodes for experiment on CNGI

Network Architecture Multi-hop self-organized wireless network Autonomous sensor nodes: nodesplaced in areas of scientific interest, form a multihop network All data converge to sink Gateway: a PC stores the data in a database and connects to Cernet2.

Node Architecture Power: Rechargeable battery DAU: Data Acquisition Unit DPU: Data Processing Unit DSRU: Data Sending and Receiving Unit

DAU Sensor Temperature sensor range: / 0-2.5V precision: ±1 Humidity sensor range: 20-90%RH / 0-2.5V precision: ±3%RH O 2 sensor range:0-20.9% / 0-2.1V precision:± 1%

DPU - ADC ADC 8-bit SAR (Successive Approximation Register)-ADC Maximum Sampling Rate: 2M SPS Analog Input: 0 2.7V

DPU - MCU TaraxCore Embedded low-power micro processor 8bit RISC processor with Harvard architecture 4 MHz System clock ROM on chip 128K×8bits 256K×8bits external RAM on chip 4K×8bits Port: 56 bi-directional tri-state I/O ports Instruction set pin Chip Watchdog with independent clock source for system reset and sleep wakeup

DPU - MCU TaraxCore Low power design P work 10mW P sleep 2mW 3.3V working voltage and 4 MHz system clock Reduce the scale of logic gates to lower the load capacitance C L Harvard architecture RISC two-phase clock pipeline Gated clock and sleep-wakeup mechanism full speed working mode low energy sleep mode

DPU - MCU TaraxCore architecture

DPU - MCU 105 pins QFP TaraxCore

DPU - OS TinyOS Modularity: system is combined with modules Reusability : modules are connected by configuration files, so modules could be reused Event-driven: work state change Schedule: FIFO/Priority Core: 15Kbytes

Main process DPU - OS

DSRU IEEE Carrier frequency: 2.4 GHz Max distance:125 m Max data transmission rate: 250 Kbps Chipcon CC2420

DSRU IEEE Frame Format

DSRU Address Information Fields Frame Control Field

DSRU Frames HELLO Frame limited broadcast for routing protocol DATA Frame Upstream, sensor nodes> sink node COMMNAD Frame Downstream, sink node> sensor nodes

DSRU HELLO Frame Payload NameTypeDescription tfmy_hopUint8_tbit7-bit6: frame type. 01-HELLO Frame, 10-DATA Frame, 11-COMMAND Frame bit5-bit0: number of hops to sink node. 63=unreachable, 0=originated by sink node tfn_flagUint8_tNeighbor identification (number of neighbors) tfmy_idUint16_t Source Node ID tfn1_idUint16_tNeighbor node1 ID tfn2_idUint16_tNeighbor node2 ID tfn3_idUint16_tNeighbor node3 ID tfn4_idUint16_tNeighbor node4 ID tfn5_idUint16_tNeighbor node5 ID tfn6_idUint16_tNeighbor node6 ID tfn7_idUint16_tNeighbor node7 ID tfn8_idUint16_tNeighbor node8 ID tfn9_idUint16_tNeighbor node9 ID tfn10_idUint16_tNeighbor node10 ID

DSRU DATA Frame Payload NameTypeDescription FMy_HopUint8_tbit7-bit6: frame type. 01-HELLO Frame, 10-DATA Frame, 11-COMMAND Frame bit5-bit0:reserved FN_FlagUint8_tLength of payload (in bytes): from FMy_Hop to the end of this data structure FMy_IDUint16_tSource Node ID FN1_IDUint16_tNext node ID (next hop) from source to sink node Other data

DSRU COMMAND Frame Payload NameTypeDescription FMy_HopUint8_tbit7-bit6: frame type. 01-HELLO Frame, 10-DATA Frame, 11-COMMAND Frame bit5-bit0:reserved FN_FlagUint8_tLength of Path (number of hops): include sink node and destination node. Maximum=10 hops FMy_IDUint16_tSink Node ID FN1_IDUint16_tNext node ID (next hop) along the path starting from sink node to destination node ……… FNx-1_IDUint16_tConsecutive hop down to the destination node FNx_IDUint16_tDestination node ……. If Length of Path<10, leave them blank FN10_IDUint16_tCommand ID

Networking and Routing Ripple – a routing protocol Upstream path: from sensor node to sink node Downstream path: from sink node to sensor node

Networking and Routing Backbone(IPv6) Sink node Sensor node upstream path setting up 1. Sink node broadcasts HELLO Frame to its one-hop neighbors 2. one-hop neighbors add route to sink node 3. one-hop neighbors broadcast HELLO Frame to their one-hop neighbors( i.e. 2 hops to sink node) 4. 2-hop nodes add route to sink node 5. All the nodes add route in the same way 6. Multiple sink node: find the closest sink node to balance the load

Networking and Routing node Next Each DATA Frame piggybacks its source node address and the next hop address. Thus at sink node, a route table can be established Route table recorded at sink node downstream path setting up 2. Using the route table, sink node can set up the downstream path to each node 3. Sink node specifies the complete path for the downstream frames (COMMNAD Frame), using the source route delivery

Features Self-organized networking Load balancing between multiple sink nodes Unidirectional link identification and avoidance High efficiency and low cost Broadcast control Networking and Routing

Limits Network Size Hops>10, slow speed of convergence Network size<200 nodes Moving Speed: Limited capability and energy of nodes Low sending speed of HELLO Frame for routing maintenance Low frequency of topology change

Gateway IPv6 communication Communicate with Control Center via IPv6 network Every node has its unique IPv6 address

Gateway Function Connect WSN with Control Center data: WSN Control Center command: WSN Control Center Reformat the packet/frame in-net address (node ID) ipv6 address command name command ID Data Base Store sensor data Query operation Determine downstream path for command

Gateway Architecture

Gateway Implementation

Control Center

PC / Windows XP GUI Sensor nodes real-time data curves Wireless sensor network topology Command input

Control Center GUI

WSN Topology Control Center

Real-Time Data Curve (Temperature)

Control Center Command table Cmmand number Command Name Descriptionparameter 1SAMPLEGet instant sample datanone 2QUERYQuery history dataquerying period of history data (times) 3MCU_ONSet MCU in work modenone 4MCU_OFFSet MCU in sleep modenone 5RF_RXSet RF in receive modenone 6RF_TXSet RF in transmit modenone 7RF_OFFSet RF in sleep modenone 8INTERVALSet sampling time intervalInterval time (seconds)

Sensor node Sensor Node

Application Central air-conditioner monitoring system

Application Permafrost monitoring of Tibet-Qinghai railway

Application Outer Space Exploration

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