1 / 10

II. Modulation & Coding

II. Modulation & Coding. Design Goals of Communication Systems. Maximize transmission bit rate Minimize bit error probability Minimize required transmission power Minimize required system bandwidth Minimize system complexity, computational load & system cost Maximize system utilization.

carla-sloan
Download Presentation

II. Modulation & Coding

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. II. Modulation & Coding

  2. Design Goals of Communication Systems • Maximize transmission bit rate • Minimize bit error probability • Minimize required transmission power • Minimize required system bandwidth • Minimize system complexity, computational load & system cost • Maximize system utilization

  3. Trades off BER and Energy per Bit Trades off BER and Normalized Rate in b/s/Hz Trades off Normalized Rate in b/s/Hz and Energy per Bit Some Tradeoffs in M-PSK Modulaion 2 1 m=4 m=3 m=1, 2 3

  4. Shannon-Hartley Capacity Theorem System Capacity for communication over of an AWGN Channel is given by: C: System Capacity (bits/s) W: Bandwidth of Communication (Hz) S: Signal Power (Watt) N: Noise Power (Watt)

  5. Shannon-Hartley Capacity Theorem Unattainable Region Practical Systems

  6. Shannon Capacity in terms of Eb/N0 Consider transmission of a symbol over an AWGN channel

  7. Let Shannon Limit

  8. Shannon Limit Shannon Limit=-1.6 dB

  9. Shannon Limit No matter how much/how smart you decrease the rate by using channel coding, it is impossible to achieve communications with very low bit error rate if Eb/N0 falls below -1.6 dB

  10. Shannon Limit Room for improvement by channel coding 16 PSK Uncoded Pb=10-5 8 PSK Uncoded Pb=10-5 QPSK Uncoded Pb = 10-5 Normalized Channel Capacity b/s/Hz BPSK Uncoded Pb = 10-5 Shannon Limit=-1.6 dB Eb/N0 10

More Related