1 / 13

Lecture 7: Channel capacity and multiplexing

Lecture 7: Channel capacity and multiplexing. Anders Västberg vastberg@kth.se 08-790 44 55. Concepts. Data rate Channel capacity Signal Bandwidth Channel Bandwidth Noise Error rate. Bandwidth limited channel Hartley’s law. C Channel capacity (bit/s) M Discrete Levels

bianca-osborn
Télécharger la présentation

Lecture 7: Channel capacity and multiplexing

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. Lecture 7: Channel capacity and multiplexing Anders Västberg vastberg@kth.se 08-790 44 55

  2. Concepts • Data rate • Channel capacity • Signal Bandwidth • Channel Bandwidth • Noise • Error rate

  3. Bandwidth limited channelHartley’s law C Channel capacity (bit/s) M Discrete Levels B Channel bandwidth (Hz)

  4. Bandwidth limited and noisy channelShannon’s law C Channel capacity (bit/s) SNR=P/N Signal to Noise ratio (not in dB!) B Channel bandwidth (Hz)

  5. Shannon’s Law

  6. Bandwidth and Capacity

  7. Multiplexing • The signals of the different users are multiplexed at the transmitter and then transmitted as one entity. • Examples of broadcast network: • Radio and TV broadcast systems • Downlinks in a mobile cellular communication system • Downlinks in a satellite communication system

  8. Multiple Access • Examples of Multiple Access systems: • Uplink in a mobile cellular system • Uplink in a satellite communication system

  9. Multiplexing/Multiple Access • Frequency division multiplexing (multiple access) (FDM/FDMA) • Channel bandwidth greater than signal bandwidth • Time division multiplexing (multiple access) (TDM/TDMA) • Channel capacity greater than signal data rate

  10. FDM/TDM

  11. Frequency divison multiplexing |H(f)| f Signal bandwidth Guard band

  12. Time divison multiplexing • Bit interleaving • Block interleaving • Synchronous TDM • Time slots fixed and pre-assigned to sources • Asynchronous TDM • Time given to sources with data to send 1 0 1 1 0 0 1 1 1 1 1 1 0 0 1 1 0 1

  13. Homework before F8 • Beskriv principen för DSSS? • Vad är snabb och långsam FHSS?

More Related