1 Wireless Sensor Networks Akyildiz/Vuran Chapter 1: Introduction

2 Wireless Sensor Networks Akyildiz/Vuran Internet, Satellite, UAV Sink Task Manager WIRELESS SENSOR NETWORK (WSN) ARCHITECTURE I.F. Akyildiz, W. Su, Y. Sankarasubramaniam, E. Cayirci, “Wireless Sensor Networks: A Survey”, Computer Networks (Elsevier) Journal, March 2002.

3 Wireless Sensor Networks Akyildiz/Vuran CHARACTERISTICS OF WSNs  Envisioned to consist of very large number of nodes, often in the order of thousands  Nodes need to be close to each other  Densities as high as 20 nodes/m 3  Asymmetric flow of information, from sensor nodes to sink  Communications are triggered by queries or events  Limited amount of energy (in many applications, it is impossible to replace or recharge)

4 Wireless Sensor Networks Akyildiz/Vuran CHARACTERISTICS OF WSNs  Mostly static topology  Low cost, size, and weight per node  Prone to failures  More use of broadcast communications instead of point-to-point  Nodes do not have a global ID such as an IP address  The security, both on physical and communication level, is more limited than in classical wireless networks

5 Wireless Sensor Networks Akyildiz/Vuran DIFFERENCES FROM AD-HOC NETWORKS  Number of sensor nodes can be several orders of magnitude higher  Sensor nodes are densely deployed and are prone to failures  The topology of a sensor network may change frequently due to node failure and node mobility  Sensor nodes are limited in power, computational capacities, and memory  May not have global ID like IP address  Need tight integration with sensing tasks

6 Wireless Sensor Networks Akyildiz/Vuran Power Unit ANTENNA Sensor ADC ProcessorMemory Transceiver Location Finding System Mobilizer n Small n Low power n Low bit rate n High density n Low cost (dispensable) n Autonomous n Adaptive SENSING UNIT PROCESSING UNIT Sensor Node Hardware

7 Wireless Sensor Networks Akyildiz/Vuran Sensor Node Hardware  Two main components  Base (Processor + Transceiver)  Sensor Board  Base + Sensor Board(s) = Sensor Node

8 Wireless Sensor Networks Akyildiz/Vuran 25 lb, 19.5 x 5.5 x 16 inch ~ 64 W ~ $6K (today) 160 KB Floppies KB RAM 4.77 MHz Original IBM PC (1981) 0.5 oz, 2.25 x 1.25 x 0.25 inch ~14 mW ~ $ KB Flash 128 KB RAM 8 MHz MICAZ Mote (2005) Sensor Node Features

9 Wireless Sensor Networks Akyildiz/Vuran Sensor Motes Timeline

10 Wireless Sensor Networks Akyildiz/Vuran Rockwell WINS Smart Dust JPL Sensor Webs Dust Examples for Sensor Nodes Examples for Sensor Nodes

11 Wireless Sensor Networks Akyildiz/Vuran MICA Mote Rene Mote weC Mote Dot Mote Examples for Sensor Nodes

12 Wireless Sensor Networks Akyildiz/Vuran Current Platforms: 1st Generation  Mica2DOT (2003)  16Kb program mem  RFM TR1000 (CSMA/ASK)  Lightweight and small  Mica2 & Cricket platform (2003)  128Kb program mem  ChipconCC1000 (CSMA/FSK)  40Khz Ultrasounders (Cricket only)  MicaZ (2004) & Telos (2005)  /Zigbee stack  Spread Spectrum radio handles multipath better  Integrated antenna (Telos only)

13 Wireless Sensor Networks Akyildiz/Vuran Current Platforms: 2nd Generation  Imote (2003) & Imote2 (2007)  Higher processing power  Bluetooth & capable (Imote2 only)  Stargate (2005) & Stargate 2.0  Pentium class processor  Linux OS => easy development (C/C++)  Higher processing capabilities => energy intensive  capable

14 Wireless Sensor Networks Akyildiz/Vuran SENSOR NODE FEATURES Processing and Storage FeatureImote (2003) Mica2 (2003) MicaZ (2004) Telos (2005) Stargate (2005) Imote 2 (2009) Speed [MHz] * Flash [kB] (Program) ,000 Serial Flash [kB] (Measurement data) N/A # N/A # SRAM / EEPROM / SDRAM ‡ [kB] (Configuration) , ,000 ◊ * Multiple processor speed levels # Imote, Stargate, and Imote 2 use a single Flash for program and measurement data ‡ Imote, Imote 2, and Telos use SRAM; Mica2 and MicaZ use EEPROM; Stargate uses SDRAM ◊ Imote 2 will have different versions, SRAM changes accordingly

15 Wireless Sensor Networks Akyildiz/Vuran SENSOR NODE FEATURES Communication and Power Feature Imote (2003) Mica2 (2003) MicaZ (2004) Telos (2005) Imote 2 Radio Frequency 2.4 GHz MHz DataRate [kb/s] (720 Δ /11,000 ) Power CarrierSense/Rx./Tx. [mA] 15 / 24 / 24 8 / 10 / 27 8 / 20 / 18 1 / 20 / 18 40/20/18 PowerSleep [mA] Radio Range 32 ft (10 m) 500 ft (150m) 300 ft (100m) 400 ft (125m) 100ft (30m) Power source AA Battery 2xAA2xAA2xAA3xAAA Δ With external Bluetooth adapter With external WLAN Different sleep levels Stargate communication and power properties depend on the connected module (Mica2,MicaZ sensors or WLAN) Stargate powered by 5-6V DC or A/C adaptor

16 Wireless Sensor Networks Akyildiz/Vuran MICAz Platform MICAz Platform  Microprocessor: Atmel ATmega128L  MHz clock  128 kB of Flash for program memory  4 kB of SRAM for data and variables  2 UARTs (Universal Asynchronous Receive and Transmit)  Serial Port Interface (SPI) bus  Dedicated hardware I2C bus  Radio: Chipcon’s CC2420 (IEEE )  250 kbit/s  External serial flash memory: 512 Kb  xbow estimates > samples  51-pin expansion connector  Eight 10-bit analog I/O  21 general purpose digital I/O  User interface: 3 programmable LEDs  Powered by two AA batteries  1850 mAh capacity Logger Flash ATMega128L  controller Analog I/O Digital I/O Freq. Tunable Radio 51-Pin Expansion Connector Antenna MMCX connector LEDs

17 Wireless Sensor Networks Akyildiz/Vuran Telos Platform  Robust  USB interface  Integrated antenna (30m-125m)  External antenna capability (~500m)  High Performance  10kB RAM, 48 KB ROM  12-bit ADC and DAC (200ksamples/sec)  Hardware link-layer encryption

18 Wireless Sensor Networks Akyildiz/Vuran Telos Platform  Single board philosophy  Robustness, Ease of use, Lower Cost  Integrated Humidity & Temperature sensor  Uses  CC2420 radio, 2.4 GHz, 250 kbps  Motorola HCS08 processor  Lower power consumption, 1.8V operation, faster wakeup time  40 MHz CPU clock, 10K RAM; 48K Flash  50m indoor; 125m outdoor ranges

19 Wireless Sensor Networks Akyildiz/Vuran SunSPOT Platform  Microprocessor: 32 bit ARM920T core  180 MHz clock  512 kB of Flash for program memory  4 MB of Flash for data  USB Connection  Radio: Chipcon’s CC2420 (IEEE )  250 kbit/s  3.7V rechargeable 720 mAh lithium-ion battery  Software: Squawk VM  Fully capable J2ME CLDC 1.1 Java VM with OS functionality  VM executes directly out of flash memory  Device drivers in Java  Automatic battery management

20 Wireless Sensor Networks Akyildiz/Vuran SENSOR NETWORKS FEATURES  APPLICATIONS:  Military, Environmental, Health, Home, Space Exploration,  Chemical Processing, Volcanoes, Mining, Disaster Relief….  SENSOR TYPES:  Seismic, Low Sampling Rate Magnetic, Thermal, Visual, Infrared, Acoustic,  Radar…  SENSOR TASKS:  Temperature, Humidity, Vehicular Movement, Lightning Condition,  Pressure, Soil Makeup, Noise Levels, Presence or Absence of Certain Types of  Objects, Mechanical Stress Levels on Attached Objects, Current Characteristics  (Speed, Direction, Size) of an Object ….

21 Wireless Sensor Networks Akyildiz/Vuran Sensor Types  Light  Thermopile  Ultraviolet  IR  Visible Light  Color sensors  Magnetic  Sound  Ultrasound  Accelerometer  Temperature  Pressure  Humidity  Touch sensors 2.25 in Microphone Accelerometer Light Temperature Sounder Magnetometer 1.25 in

22 Wireless Sensor Networks Akyildiz/Vuran Manufacturers of Sensor Nodes  Millenial Net (  iBean sensor nodes  Ember (  Integrated IEEE stack and radio on a single chip  Memsic (  Mica2 mote, Micaz, Dot mote and Stargate Platform  Intel Research  Stargate, iMote  Dust Inc  Smart Dust  Cogent Computer (  XYZ Node (CSB502) in collaboration with  Mote iv – Telos Mote

23 Wireless Sensor Networks Akyildiz/Vuran Manufacturers of Sensor Nodes  In-Q-Tel provides distributed data collection solutions with sensor network deployment  ENSCO Inc. invests in wireless sensor networks for meteorological applications  EMBER provides wireless sensor network solutions for industrial automation, defense, and building automation  H900 Wireless SensorNet System(TM), the first commercially available end-to-end, low-power, bi-directional, wireless mesh networking system for commercial sensors and controls is developed by the company called Sensicast Systems. The company targets wide range of commercial applications from energy to homeland security

24 Wireless Sensor Networks Akyildiz/Vuran Manufacturers of Sensor Nodes  The Memsic (formerly Crossbow) wireless sensor products and its environmental monitoring and other related industrial applications of such as surveillance, bridges, structures, air quality/food quality, industrial automation, process control are introduced.  Japan's Omron Corp has two wireless sensor projects in the US that it hopes to commercialize in the near future. Omron's Hagoromo Wireless Web Sensor project consists of wireless nodes equipped with various sensing abilities for providing security for major cargo-shipping ports around the world

25 Wireless Sensor Networks Akyildiz/Vuran Manufacturers of Sensor Nodes  Millennial Net builds wireless networks combining sensor interface endpoints and routers with gateways for industrial and building automation, security, and telemetry  CSEM provides sensing and actuation solutions  Dust Inc. develops the next-generation hardware and software for wireless sensor networks  Silicon Labs designs sensors used in medical, automotive, industrial, and military applications to cost-effective designs for handheld consumer appliances, barcode readers, and wireless computer input devices

26 Wireless Sensor Networks Akyildiz/Vuran Manufacturers of Sensor Nodes  Melexis produces advanced integrated semiconductors, sensor ICs, and programmable sensor IC systems.  ZMDI designs, manufactures and markets high performance, low power mixed signal ASIC and ASSP solutions for wireless and sensor integrated circuits.  Chipcon produces low-cost and low-power single-chip 2.4 GHz ISM band transceiver design for sensors.  ZigBee Alliance develops a standard for wireless low-power, low-rate devices.