Digital Communications, 2001, Prentice Hall (Chapter 1). – Simon Haykin, Communication Systems, 2010, Wiley (Background and preview). – John G. Proakis, Masoud Salehi, Digital Communications, 2008, McGraw-Hill (Chapter 1).
this is about... transferring information • Some issues: – Can we precisely define information? – How can it and its quality be measured? – Are there any limitations to the amount of information we can transfer? • And the answer is...
this is about... transferring information • Some issues: – Can we precisely define information? – How can it and its quality be measured? – Are there any limitations to the amount of information we can transfer? • And the answer is... ?
this is about... transferring information • Some issues: – Can we precisely define information? – How can it and its quality be measured? – Are there any limitations to the amount of information we can transfer? • And the answer is... INFORMATION THEORY (Block 2) Source: Wikipedia !
carried out at the physical layer? WIFI CARD in ADSL modem Radio frequency -RF (analog) Base- band (digital) Upper layers (2,3...) • Adaptation to the medium. • Information protection. • Sharing resources. • Signal generation. • Interface between RF and upper layers. • Evaluation and compensation of channel distortions. • …...........................................................
carried out at the physical layer? WIFI CARD in ADSL modem Radio frequency -RF (analog) Base- band (digital) Upper layers (2,3...) • Adaptation to the medium. • Information protection. • Sharing resources. • Signal generation. • Interface between RF and upper layers. • Evaluation and compensation of channel distortions. • …...........................................................
Already known for those familiar with Comunication Theory. – They are evaluated for each level/layer, point to point. – Basic issue: limitations and tradeoffs → optimization.
Already known for those familiar with Comunication Theory. – They are evaluated for each level/layer, point to point. – Basic issue: limitations and tradeoffs → optimization. iDude
Already known for those familiar with Comunication Theory. – They are evaluated for each level/layer, point to point. – Basic issue: limitations and tradeoffs → optimization. iDude SNR, Eb/N0
Already known for those familiar with Comunication Theory. – They are evaluated for each level/layer, point to point. – Basic issue: limitations and tradeoffs → optimization. iDude SNR, Eb/N0 Available power
Already known for those familiar with Comunication Theory. – They are evaluated for each level/layer, point to point. – Basic issue: limitations and tradeoffs → optimization. iDude SNR, Eb/N0 Available power Transmission rate
Already known for those familiar with Comunication Theory. – They are evaluated for each level/layer, point to point. – Basic issue: limitations and tradeoffs → optimization. iDude SNR, Eb/N0 Bandwidth Available power Transmission rate
Already known for those familiar with Comunication Theory. – They are evaluated for each level/layer, point to point. – Basic issue: limitations and tradeoffs → optimization. iDude SNR, Eb/N0 Bandwidth Available power Transmission rate Error probability
Already known for those familiar with Comunication Theory. – They are evaluated for each level/layer, point to point. – Basic issue: limitations and tradeoffs → optimization. iDude SNR, Eb/N0 Bandwidth Available power Transmission rate Error probability Distortion Interference
(TX) Medium access Medium access (RX) (RX) R max ________ SNR ____ Allowed interference ____ Reliability ____ BW max ____ P max R 2 SNR 2 BW 2 ... R 1 SNR 1 BW 1 ...
(TX) Medium access Medium access (RX) (RX) R max ________ SNR ____ Allowed interference ____ Reliability ____ BW max ____ P max …...... R 2 SNR 2 BW 2 ... R 1 SNR 1 BW 1 ... R n SNR n BW n ...
(TX) Medium access Medium access (RX) (RX) R max ________ SNR ____ Allowed interference ____ Reliability ____ BW max ____ P max …...... R 2 SNR 2 BW 2 ... R 1 SNR 1 BW 1 ... R n SNR n BW n ... …...... R' 2 SNR' 2 BW' 2 ... R' 1 SNR' 1 BW' 1 ... R' n SNR' n BW' n ...
(TX) Medium access Medium access (RX) (RX) R max ________ SNR ____ Allowed interference ____ Reliability ____ BW max ____ P max …...... R 2 SNR 2 BW 2 ... R 1 SNR 1 BW 1 ... R n SNR n BW n ... …...... R' 2 SNR' 2 BW' 2 ... R' 1 SNR' 1 BW' 1 ... R' n SNR' n BW' n ... SHARE AND MANAGE LIMITED RESOURCES
(TX) Medium access Medium access (RX) (RX) R max ________ SNR ____ Allowed interference ____ Reliability ____ BW max ____ P max …...... R 2 SNR 2 BW 2 ... R 1 SNR 1 BW 1 ... R n SNR n BW n ... …...... R' 2 SNR' 2 BW' 2 ... R' 1 SNR' 1 BW' 1 ... R' n SNR' n BW' n ... SHARE AND MANAGE LIMITED RESOURCES Information Theory
Demodulation (RX) (RX) R mod ____ SNR ____ Es/N0 ____ P s (e) ____ BW mod ____ P mod P b (e) _____ Eb/N0 _____ R b ADAPT SIGNALS TO THE CHANNEL AND IMPROVE PERFORMANCE
Demodulation (RX) (RX) R mod ____ SNR ____ Es/N0 ____ P s (e) ____ BW mod ____ P mod P b (e) _____ Eb/N0 _____ R b ADAPT SIGNALS TO THE CHANNEL AND IMPROVE PERFORMANCE Information Theory
(TX) Channel Channel decoding decoding (RX) (RX) P b (e) ________ Eb/N0(out) ____ R b P' b (e)<P b (e) _____ Eb/N0(in) _____ R' b <R b PROTECT INFORMATION INTEGRITY AT THE COST OF DATA RATE
(TX) Channel Channel decoding decoding (RX) (RX) P b (e) ________ Eb/N0(out) ____ R b P' b (e)<P b (e) _____ Eb/N0(in) _____ R' b <R b PROTECT INFORMATION INTEGRITY AT THE COST OF DATA RATE Information Theory
– Abstract operations / layers (“divide and conquer”). – HW implementation. • Recall always – Basic scheme of Digital Communications. – Design and evaluation parameters. – Concepts from Communication Theory and Signals and Systems. • Main purpose: – Given some resources, and some target conditions and target performance, manage to evaluate and/or design the appropriate subsystems.