IoT Control Units and Communication Models

IoT Communication models and Control units

1. Chapter -2 Components of IoT Control Units Communication Modules Bluetooth – Zigbee – Wifi - GPS Dr. Y V Srinivasa Murthy School of Computer Science & Engg . (SCOPE) VIT Vellore

2. Outline Control units Communication modules Bluetooth Zigbee Wifi IoT Protocols

3. Control Units The Internet of Things is rarely discussed without the conversation steering to data and the new Data Economy . Sensors are the source of IoT data . Driven by new innovations in materials and nanotechnology, sensor technology is developing at a never before seen pace, with a result of increased accuracy, decreased size and cost, and the ability to measure or detect things that weren’t previously possible.

4. Transducer A better term for a sensor is a transducer . Physical device that converts one form of energy into another . The transducer converts some physical phenomenon into an electrical impulse that can then be interpreted to determine a reading.

5. Some Sensors

6. Actuators Another type of transducer that you will encounter in many IoT systems is an actuator. In simple terms, an actuator operates in the reverse direction of a sensor . It takes an electrical input and turns it into physical action . For instance, an electric motor, a hydraulic system, and a pneumatic system.

7. Sensor to Actuator Flow

8. Sensors and Actuators Humidity Sensor Level/tilt sensor Pressure sensor Temperature Sensor Motion sensor Proximity sensor Optical sensor Acceleration sensor Load sensor Vibration, chemical, flow….. LEDs Relays Motors Lasers Solenoids Speakers LCD displays

9. Communication Modules Bluetooth Zigbee Wifi

10. Short range wireless application areas Voice Data Audio Video State Bluetooth ACL/HS x Y Y x x Bluetooth SCO/ eSCO Y x x x x Bluetooth low energy x x x x Y Wi-Fi (VoIP) Y Y Y x Wi-Fi Direct Y Y Y x x ZigBee x x x x Y ANT x x x x Y 10 Low Power State = low bandwidth, low latency data

11. How much energy does traditional Bluetooth use? Traditional Bluetooth is connection oriented . When a device is connected, a link is maintained, even if there is no data flowing. Sniff modes allow devices to sleep, reducing power consumption to give months of battery life Peak transmit current is typically around 25mA Even though it has been independently shown to be lower power than other radio standards, it is still not low enough power for coin cells and energy harvesting applications 11

12. What is Bluetooth Low Energy? Bluetooth low energy is a NEW, open, short range radio technology Blank sheet of paper design Different to Bluetooth classic (BR/EDR) Optimized for ultra low power Enable coin cell battery use cases < 20mA peak current < 5 uA average current 12

13. Basic Concepts of Bluetooth 4.0 Everything is optimized for lowest power consumption Short packets reduce TX peak current Short packets reduce RX time Less RF channels to improve discovery and connection time Simple state machine Single protocol Etc. 13

14. Bluetooth low energy factsheet Range: ~ 150 meters open field Output Power: ~ 10 mW (10dBm) Max Current: ~ 15 mA Latency: 3 ms Topology: Star Connections: > 2 billion Modulation: GFSK @ 2.4 GHz Robustness: Adaptive Frequency Hopping, 24 bit CRC Security: 128bit AES CCM Sleep current: ~ 1 μ A Modes: Broadcast, Connection, Event Data Models, Reads, Writes 14

15. ZigBee

16. Introduction ZigBee is a technological standard designed for control and sensor networks Based on the IEEE 802.15.4 Standard Created by the ZigBee Alliance

17. Introduction Operates in Personal Area Networks (PAN ’ s) and device-to-device networks Connectivity between small packet devices Control of lights, switches, thermostats, appliances, etc.

18. History Developement started 1998, when many enginereers realized that WiFi and Bluetooth were going to be unsuitable for many applications IEEE 802.15.4 standard was completed in May 2003

19. ZigBee Alliance Organization defining global standards for reliable, cost‐effective, low power wireless applications A consortium of end users and solution providers, primarily responsible for the development of the 802.15.4 standard Developing applications and network capability utilizing the 802.15.4 packet delivery mechanism

20. Characteristics Low cost Low power consumption Low data rate Relatively short transmission range Scalability Reliability Flexible protocol design suitable for many applications

21. Security Encryption specified for MAC, Network and APS layers Encryprion/Authentication mode CCM(CTR +CBC-MAC) CTR is a counter based encryption mode CBC-MAC provides data integrity All security is based on 128bit key and AES-128 block encryption method

22. Applications PERSONAL HEALTH CARE ZigBee LOW DATA-RATE RADIO DEVICES HOME AUTOMATION CONSUMER ELECTRONICS TV VCR DVD/CD Remote control security HVAC lighting closures PC & PERIPHERALS consoles portables educational TOYS & GAMES INDUSTRIAL & COMMERCIAL monitors sensors automation control mouse keyboard joystick monitors diagnostics sensors

23. ZigBee/IEEE 802.15.4 PHY 868MHz / 915MHz / 2.4GHz MAC Application Network Star / Mesh / Cluster-Tree Security 32- / 64- / 128-bit encryption API ZigBee Alliance IEEE 802.15.4 Customer ZigBee Alliance -“ the software” -Network, Security & Application layers -Brand management IEEE 802.15.4 -“the hardware” -Physical & Media Access Control layers

24. IEEE 802.15.4 IEEE 802.15.4 Architecture IEEE 802.15.4 868/915 MHz PHY IEEE 802.15.4 2400 MHz PHY IEEE 802.15.4 MAC IEEE 802.2 LLC Other LLC Data Link Controller (DLC) Networking App Layer ZigBee Application Framework

25. IEEE 802.15.4 Physical Layer PHY functionalities: Activation and deactivation of the radio transceiver Energy detection within the current channel Link quality indication for received packets Clear channel assessment for CSMA-CA Channel frequency selection Data transmission and reception

26. PHY frame structure PHY packet fields Preamble (32 bits) – synchronization Start of packet delimiter (8 bits) – shall be formatted as “11100101” PHY header (8 bits) –PSDU length PSDU (0 to 127 bytes) – data field Preamble Start of Packet Delimiter PHY Header PHY Service Data Unit (PSDU) 4 Octets 0-127 Bytes Sync Header PHY Payload 1 Octets 1 Octets Frame Length (7 bit) Reserve (1 bit)

27. Operating frequency bands The standard specifies two PHYs : 868 MHz/915 MHz direct sequence spread spectrum (DSSS) PHY (11 channels) 1 channel (20Kb/s) in European 868MHz band 10 channels (40Kb/s) in 915 (902-928)MHz ISM band 868MHz/ 915MHz PHY 868.3 MHz Channel 0 Channels 1-10 928 MHz 902 MHz 2 MHz

28. Operating frequency bands 2450 MHz direct sequence spread spectrum (DSSS) PHY (16 channels) 16 channels (250Kb/s) in 2.4GHz band 2.4 GHz Channels 11-26 2.4835 GHz 5 MHz 2.4 GHz PHY

29. IEEE 802.15.4 MAC Layer Traffic Type Periodic data e.g. sensors Intermittent data e.g. light switch Repetitive low latency data e.g. mouse

30. IEEE 802.15.4 MAC Layer Device Classes Full function device (FFD) Can function in any topology Capable of being Network coordinator Can talk to any other device (FFD/RFD) Reduced function device (RFD) Limited to star topology Cannot become network coordinator Talks only to FFDs Address All devices must have 64 bit IEEE addresses Short (16 bit) addresses can be allocated to reduce packet size

31. IEEE 802.15.4 MAC Layer Frame Types Data Frame used for all transfers of data Beacon Frame used by a coordinator to transmit beacons Acknowledgment Frame used for confirming successful frame reception MAC Command Frame used for handling all MAC peer entity control transfers

32. IEEE 802.15.4 MAC Layer Transmission Mode Slotted (Beacon enable mode ) Periodic data and Repetitive low latency data using. Un-slotted (Non-Beacon enable mode) Intermittent data using.

33. ZigBee Network Topologies Star Mesh Cluster Tree PAN coordinator Full Function Device Reduced Function Device

34. ZigBee Network Topologies Star Topology Advantage Easy to synchronize Low latency Disadvantage Small scale

35. ZigBee Network Topologies Mesh Topology Advantage Robust multihop communication Network is more flexible Lower latency Disadvantage Route discovery is costly Needs storage for routing table

36. ZigBee Network Topologies Cluster Tree Advantage Low routing cost Allow multihop communication Disadvantage Route reconstruction is costly Latency may be quite long

37. ZigBee and Bluetooth Comparison Optimized for different applications ZigBee Smaller packets over large network Mostly Static networks with many, infrequently used devices Home automation, toys, remote controls, etc. Bluetooth Larger packets over small network Ad‐hoc networks File transfer Screen graphics, pictures, handsfree audio, Mobile phones, headsets, PDAs, etc.

38. ZigBee and Bluetooth Comparison Feature(s) Bluetooth ZigBee Power Profile days years Complexity complex Simple Nodes/Master 7 64000 Latency 10 seconds 30 ms – 1s Range 10m 70m ~ 300m Extendibility no Yes Data Rate 1 Mbps 250 Kbps Security 64bit, 128bit 128bit AES and Application Layer

39. ZigBee and Bluetooth Comparison SHORT < RANGE > LONG LOW < DATA RATE > HIGH PAN LAN TEXT GRAPHICS INTERNET HI-FI AUDIO STREAMING VIDEO DIGITAL VIDEO MULTI-CHANNEL VIDEO 802.15.1 Bluetooth1 802.15.1 Bluetooth 2 802.15.4 ZigBee 802.11b 802.11a/HL2 & 802.11g