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Smart Home Technologies

Smart Home Technologies. Networking. Networking for Smart Homes. Requirements Network Topologies Technologies Networking Service Discovery. Requirements. Noise Rejection Network has to allow for reliable communication Requires preservation of data and synchronization of data lines

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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

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