1 / 31

Wireless Communication

Wireless Communication. RF Design. Considerations when starting an RF design: How many members/nodes will participate the wireless network? What is the required range between the devices Is there a special need for low power consumption? Are there common standards that have to be met?.

nelly
Download Presentation

Wireless Communication

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Wireless Communication

  2. RF Design • Considerations when starting an RF design: • How many members/nodes will participate the wireless network? • What is the required range between the devices • Is there a special need for low power consumption? • Are there common standards that have to be met?

  3. Point to Point or Star topology

  4. Range and Data Rate • How far nodes would be? • How much Data need to be transferred per unit time?

  5. Range and Data Rate

  6. Power Consumption • Is power consumption a factor? • Source of Power • Battery powered • Ease of replenishing power source? • Environment • Obstruction, multipath, Line of sight

  7. Power Consumption- Duty Cycle

  8. Power Consumption- Duty Cycle • Use the lowest possible duty cycle • Send data only when needed, do not send more data than necessary • Use the highest data rate if you can (trade-off vs. range) • Watch out for protocol-related overhead • Use the lowest possible voltage • RF chips have reduced current draw at lower voltages • Low voltage degrades RF performance

  9. Selecting Wireless Solution • How to choose the perfect wireless solution: • Does the application need to associate with an existing system? • What kind of software protocols fit the application best? • Are there regulations to be considered? • How much time/resources are available to get the product to market?

  10. Regulation: ISM Bands

  11. Regulation: 2.4 GHz ISM Bands • 2.4 GHz Pros • Same solution for all markets without SW/HW alterations • Large bandwidth available, allows many separate channels and high datarates • More compact antenna solution than below 1 GHz • • 2.4 GHz Cons • Shorter range than a sub 1 GHz solution (with the same current consumption) • Many possible interferers are present in the band

  12. Regulation: sub 1 GHz ISM Bands • The ISM bands under 1 GHz are not world-wide. Limitations vary a lot from region to region and getting a full overview is not an easy task • Sub 1GHz Pros • Better range than 2.4 GHz with the same output power and current consumption • Lower frequencies have better penetration through concrete and steel (buildings and office environments) compared to 2.4 GHz • Sub 1GHz Cons • No worldwide solution possible. Since different bands are used in different regions a custom solution has to be designed for each area • Duty cycle restrictions in some regions

  13. Antenna Design

  14. Application Presentation ISO OSI 7-layer model Session IEEE 802 standards Transport Network Logical Link Control Data Link Medium Access (MAC) Physical (PHY) Physical Wireless Networks • Wireless networks are standardized by IEEE. • Under 802 LAN MAN standards committee.

  15. Short range Wireless Communication • Bluetooth – 802.15.1 • Zigbee - 802.15.4 • Wi-Fi - 802.11 • WPAN (wireless personal area network) Vs WLAN(wireless local area network)

  16. Bluetooth • Designed for short range networks also called piconets • Provide device connectivity to computer peripherals • Printers, Smartphone's , PDA’s • Keyboard, mouse • versions • Bluetooth 1.x • Bluetooth 2.x – Extended data rate • Bluetooth 3.0 – High Speed • Bluetooth 4.0 – Bluetooth Low Energy

  17. Bluetooth • 2.4 GHz frequency range • Use FHSS with 79 channels and 1 MHz bandwidth • Low Power Consumption • Typical range is about 10 meters extendable up to 100 meters • Data Rates • Bluetooth 1.2 - 1Mbps (721 Kbps) • Bluetooth 2.0 – Extended data rate - 3 Mbps (2.1Mbps) • Bluetooth 3.0 – High Speed - (24Mbps with 802.11) • Bluetooth 4.0 – Bluetooth Low Energy (200 Kbps)

  18. Bluetooth • Master slave configuration • Slaves communicate only with their master in a point-to-point fashion • Master’s transmissions may be either point-to-point or point-to-multipoint • besides in an active mode, a slave device can be in the parked or standby modes so as to reduce power consumptions

  19. Bluetooth Topology a) Piconet with one slave b) Piconet with multiple slaves c) a Scatternet

  20. Bluetooth programming • Similar to network programming • Steps in programming • Choosing a communication partner • Each device has a 48 bit address given by manufacturer similar to mac addresses • Each device has a symbolic name but actually 48 bit address is used for communication • Master broadcast a search message and slave respond. Searching take considerable time.

  21. Bluetooth programming • Steps in programming • Choosing a Transport protocol • Choose among many available • RFCOMM - Establishes point to point communication over which reliably streams of data can be exchanged • L2CAP - Connection oriented protocol that sends individual datagram's of fixed maximum length • Selecting port number – 1-30 for RFCOMM, Odd numbers in range 1 to 32767 for L2CAP

  22. Bluetooth programming • Steps in programming • Making a outgoing connection • Accepting an incoming connection • Sending and receiving data • Uses sockets programming framework similar to network programming • Functions like create, bind, listen, connect, accept, receive and send

  23. BLE-Bluetooth Low Energy • For small form factor devices in healthcare, fitness, security and home entertainment industries • Simplified protocol • 40, 2MHz channels • Range up to 50 meters • Not Compatible with Classic Bluetooth

  24. Wi-Fi – 802.11 • Provide wireless connectivity for fixed, portable and moving stations within alocal area • Internet access • Public – Wi-Fi hotspots • Wi-Fi Direct • For file sharing and media sharing • Range 30-100m

  25. Overview, 802.11 Architecture ESS Existing Wired LAN AP AP STA STA STA STA BSS BSS Infrastructure Network STA STA Ad Hoc Network Ad Hoc Network BSS BSS STA STA

  26. Zigbee – 802.15.4 • Applications- WSN, Industrial Control Network • Frequencies and data rates • 868 MHz - 20Kbps • 915 MHz – 40 Kbps • 2.4 GHz – 250 kbps • Self organized, Multi Hop and reliable mesh networking • Zigbee RF4CE - Radio frequency based remote control

  27. Zigbee – 802.15.4

  28. Zigbee Layer Structure

  29. Zigbee

  30. Comparison between Bluetooth, Zigbee and Wi-Fi

  31. Radio interference • Adaptive Frequency hopping(Bluetooth) • CSMA CA

More Related