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Smart Home Technologies

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Smart Home Technologies

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  1. Smart Home Technologies Networking

  2. Networking for Smart Homes • Requirements • Network Topologies • Technologies • Networking • Service Discovery

  3. Requirements • Noise Rejection • Network has to allow for reliable communication • Requires preservation of data and synchronization of data lines • Bandwidth • Smart Homes can contain many sensors and actuators • Sensor data can be generated at different rates • Connectivity • Sensors have to be connected to processing units • Integration • Network structures have to be integrated into buildings • Privacy and Security • Smart Home networks will transfer private and sensitive data

  4. Bandwidth Requirements Example • Camera (15) – 320x240, 8-bit color • Motion (15) – distance, direction, velocity • Temperature (12) • Humidity (12) • Light (12) – frequency, intensity • Microphone (12) – 8000 Hz • Gas (4) • Pressure (100)

  5. Bandwidth Requirements

  6. Audio Phones (16 kHz, 8 bit) Radios (44 kHz, 16 bit) TVs (44 kHz, 16 bit) Media players (44 kHz, 16 bit) Monitoring (16 kHz, 8 bit) 2.4 Mbits/sec (one each) Internet, control, … Video Phones (30fps, 320x240, 8-bit color) TVs (60 fps, 1024x768, 24-bit color) Video players (60 fps, 1024x768, 24-bit color) Monitoring (30 fps, 320x240, 8-bit color) ~6.9 Gbits/sec (one each) Other Bandwidth Requirements

  7. Other Bandwidth Requirements

  8. Other Network Requirements • Worst-case throughput: 10 Gbits/sec • Maximum throughput: 5 Gbits/sec • Quality of Service (QoS) • Audio, video • Plug and play (service discovery)

  9. Network Topologies • Infrastructure-Based Networks • Pre-defined routes through the network • Nodes can directly address each other and routers forward packets appropriately • Addition of nodes changes the routing pattern • Point-To-Point Networks • Every node has a connection to every other node • Communication is directly between the nodes • High overhead setting up the connections for new nodes • Ad-Hoc Networks • Routes are determined “on the fly” and can change • Nodes forward signals for other nodes • Addition of nodes can be handled relatively straightforwardly

  10. Topologies (Point-to-Point) • Every device is connected to every other device • Good points • simplest approach • no addressing needed • everyone is your neighbor • you can always talk to your neighbor • Bad points • number of ports/lines grow relatively quickly with the number of devices A B C D

  11. Topologies (Hierarchy) • Devices are connected via hubs to other devices • If everyone is connected to a single hub, it is called a Star topology • Good points • fewer connections • devices can have neighborhoods • Bad points • you need an address • you may have to wait to talk to a neighbor • asymmetric communication with some devices A B C D

  12. Topologies (Broadcast) • All of the devices are connected to a single wire • Good points • single wire • everyone is your neighbor • Bad points • you need an address • you may have to wait to talk to anyone • collisions can occur • communication times become statistical A B C D

  13. Physical Addresses • If more than two devices are on the same wire (bus), you will need an address to send and receive data • Approaches • separate vs. combined data/address lines • hardwired vs. selectable address • Issues • as the number of devices increase, the address space (size of the address) must increase • hardwired addresses may tell you nothing about the network topology • addresses will be used up by devices that might not be on-line • so your address space may be too big, causing too much overhead 0001 A 1111 B 1000 C 1100 D

  14. Virtual Addresses • A solution to some physical address problems is a virtual address • the address space (size of the address) can be reduced by only giving addresses to on-line devices • addresses can be set up to support network topology • Approaches • fixed vs. run-time addresses • universal vs. p-to-p addresses • Issues • how to assign them • their relationship to the physical address 00 A 01 B 10 C 11 D

  15. Network Technologies • Wired • Phone Line • Power Line • New Wire • Wireless • RF • Infrared

  16. Wired Network Technology Examples • Phone line • Home Phoneline Networking Alliance (HomePNA) • Power line • X10 • Consumer Electronics Bus (CEBus) • HomePlug • LonWorks • New wire • Ethernet (coax, twisted pair, optical fiber) • Universal Serial Bus (USB) • IEEE 1394 Firewire • Home Audio Video Interoperability (HAVi) • Specialty: audio, video

  17. Phoneline Networking • Home Phoneline Networking Alliance (HomePNA) • www.homepna.org • IEEE 802.3 (Ethernet) • Carrier Sense Multiple Access with Collision Detect (CSMA/CD) • 10 Mbps (HPNA 2.0) • Length: 500 feet

  18. HomePNA Packet

  19. HomePNA Frequencies • Standard voice (POTS): 20Hz - 3.4kHz • UADSL: 25kHz - 1.1MHz • Home network: 5.5MHz - 9.5MHz

  20. Phoneline Network Issues • Random wiring topologies & signal attenuation • Home phoneline wiring system is a random “tree” topology • Simply plugging in the phone or disconnecting the fax changes the tree • This topology can cause signal attenuation • Signal noise • Appliances, heaters, air conditioners, consumer appliances & telephones can introduce signal noise onto the phone wires

  21. Powerline Networking • Ubiquity of power lines • 10+ Mbps • Technologies • X10 • Consumer Electronics Bus (CEBus) • HomePlug • LonWorks

  22. X10 • X10 controllers send signals over existing AC wiring to receiver modules • X10 technology transmits binary data using the Amplitude Modulation (AM) technique • www.x10.com

  23. X10 • To differentiate the data symbols, the carrier uses the zero-voltage crossing point of the 60Hz AC sine wave on the cycle’s positive or negative transition • Synchronized receivers accept the carrier at each zero-crossing point • X10 uses two zero crossings to transmit a binary digit so as to reduce errors

  24. X10 • Every bit requires a full 60 Hertz cycle and thus the X10 transmission rate is limited to only 60 bps • Usually a complete X10 command consists of two packets with a 3 cycle gap between each packet • Each packet contains two identical messages of 11 bits (or 11 cycles) each • A complete X-10 command consumes 47 cycles that yields a transmission time of about 0.8s

  25. Consumer Electronics Bus (CEBus) • Open standard providing separate physical layer specification for communication on power lines and other media • Electronic Industries Association (EIA-600) • www.cebus.org • Data packets are transmitted by the transceiver at about 10 Kbps • Carrier Sense Multiple Access/Collision Detect (CSMA/CD) • Employing spread spectrum technology (100Hz-400 Hz)

  26. OSI and CEBus (EIA-600)

  27. Spread Spectrum Modulation • Frequency spectrum of a data-signal is spread using a code uncorrelated with that signal • Sacrifices bandwidth to gain signal-to-noise performance

  28. HomePlug • HomePlug Powerline Alliance • www.homeplug.org • Spread-spectrum technology

  29. HomePlug • Speed • Support file transfers at 10BaseT-like rates • Either node-to-node file transfer or scenarios with multiple nodes performing simultaneous file transfers • HomePlug 1.0 (14 Mbps) • Voice over IP (VoIP) • Maintain adequate QoS while supporting multiple, simultaneous VoIP calls while other nodes are transferring files and during multiple media streams

  30. HomePlug • Interoperability • Interoperate with other networking technologies • Co-exist with existing powerline networking technologies such as X-10, CEBus and LonWorks • Security • Contain strong privacy features • Support multiple logical networks on a single physical medium • Be applicable to markets in North America, Europe and Asia

  31. LonWorks • Local Operation Networks (LonWorks) • Developed by Echelon Corporation • www.echelon.com • Provides a peer-to-peer communication protocol, implementing Carrier Sense Multiple Access (CSMA) techniques • 1.25 Mbps • Works for other wired and wireless media

  32. LonWorks • A common message-based communications protocol • LonTalk protocol implements all seven layers of the OSI model using a mixture of hardware and firmware on a silicon chip • Protocol can be run as fast as 20 MHz

  33. Powerline Network Issues • Noise • Switching power supplies • Wound motors • Vacuum cleaners, kitchen appliances, drills • Dimmers • Security • Signal attenuation

  34. New Wire Networking • Ethernet (coax, twisted pair, optical fiber) • Universal Serial Bus (USB) • IEEE 1394 Firewire • Home Audio Video Interoperability (HAVi) • Specialty: audio, video

  35. Ethernet • IEEE 802.3 • CSMA/CD • Up to 1 Gbps • IEEE 802.3ae • 10GBase-X, 10 Gps • Lengths up to 40 km • www.ethermanage.com/ethernet

  36. IEEE 802.3

  37. Universal Serial Bus (USB) • www.usb.org • 480 Mbps • Plug and Play • Hot pluggable • Up to 127 devices simultaneously • Powered bus • 5m maximum cable length

  38. IEEE 1394 Firewire (i.LINK) • Digital interface • No need to convert digital data into analog and tolerate a loss of data integrity • Transferring data @ 100, 200, 400 Mbps • Physically small • The thin serial cable can replace larger and more expensive interfaces

  39. IEEE 1394 Firewire • No need for terminators or device IDs • Hot pluggable • Users can add or remove 1394 devices with the bus active • Scaleable architecture • May mix 100, 200, and 400 Mbps devices on a bus

  40. IEEE 1394 Firewire • It can connect up to 63 devices @ transfer rate of 400Mbps • Up to 16 nodes can be daisy- chained through the connectors • Standard cables up to 4.5 m in length for a total standard cable length of 72 m

  41. IEEE 1394 Firewire • Flexible topology • Support of daisy chaining and branching for true peer-to-peer communication • Non-proprietary

  42. IEEE 1394b • 1394b is a significant enhancement to the basic 1394 specification that enables: • Speed increases to 3.2 Gbps • Distances of 100 meters on UTP-5, plastic optical fiber and glass optical fiber • Significantly reduces latency times by using arbitration • Fully backwards compatible with the current 1394 and 1394a specifications

  43. I2C (Inter-Integrated Circuit) • One of the oldest controller buses • Philips (1980s) • Low-cost chip-to-chip communication link • uses two wires to form a clocked serial bus • one called Clock (SCL) and the other Data (SDA) • the SDA carries address, selection, control, and data • Overview • multi-master bus (up to 1024 devices) • can run at speed up to 3.4 Mbps • can be used as a SAN • but normal ranges are on the order of 14 cm

  44. Home Audio Video Interoperability (HAVi) • HAVi is a digital Audio Video networking initiative that provides a home networking software specification • Seamless interoperability among home entertainment products • Designed to meet the particular demands of digital audio and video • www.havi.org

  45. HAVi • Defines operating-system-neutral middleware that manages: • Multi-directional AV streams • Event schedule • Registries • Takes advantage of chips built into modern audio and video appliances • Provides the management function of a dedicated audio-video networking system • IEEE 1394 (i. LINK or FireWire) has been chosen as the interconnection medium

  46. Specialty Wiring • Audio • Coax • RCA • Speaker wire • Video • Coax • RCA • VGA • ~100m maximum cable lengths

  47. Automotive Inspired Busses

  48. LIN (Local Interconnect Network) • Designed for European cars (still used) • Very simple • single wire • single mastered bus • Overview • 1 master, up to 16 Slaves • uses a message-based protocol • maximum distance of 40 m • Two data rates • 9,600 and 19.2 Kbps

  49. CAN(Controller Area Network ) • CAN was designed to support emission control system in European cars • but became a general automation control bus • Capable of • high-speed (1 Mbits/s) data transmission over short distances (40 m) • low-speed (5 kbits/s) transmissions at lengths of up to 10,000 m • Overview • a multi-master bus • highly fault tolerant • Built-in support for error detection and handling

  50. MOST(Media Oriented System Transport) • An inexpensive automotive and appliance network • 25 Mbps fiber-optic bus • for real-time data transfer • used in surround-sound systems and CD and DVD players