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Francisco J. Escribano, 2014-15
DIGITAL COMMUNICATIONS
Block 1
Introduction to Digital Communications
2
Digital Communications: introduction
3
Digital Communications: introduction
COMMUNICATIONTHEORY
4
Digital Communications: introduction
COMMUNICATIONTHEORY
BASICCONCEPTS
5
Digital Communications: introduction
COMMUNICATIONTHEORY
DIGITALCOMMUNICATIONS
BASICCONCEPTS
6
Digital Communications: introduction
COMMUNICATIONTHEORY
DIGITALCOMMUNICATIONS
BASICCONCEPTS
ADVANCEDCONCEPTS
7
Digital Communications: introduction
COMMUNICATIONTHEORY
DIGITALCOMMUNICATIONS
BASICCONCEPTS
ADVANCEDCONCEPTS
8
Digital Communications: introduction
COMMUNICATIONTHEORY
DIGITALCOMMUNICATIONS
COMMUNICATIONSYSTEMS
BASICCONCEPTS
ADVANCEDCONCEPTS
9
Digital Communications: introduction
COMMUNICATIONTHEORY
DIGITALCOMMUNICATIONS
MOBILECOMMUNICATIONS
COMMUNICATIONSYSTEMS
BASICCONCEPTS
ADVANCEDCONCEPTS
10
Digital Communications: introduction
COMMUNICATIONTHEORY
DIGITALCOMMUNICATIONS
RADIATION ANDRADIOCOMMUNICATION
MOBILECOMMUNICATIONS
COMMUNICATIONSYSTEMS
BASICCONCEPTS
ADVANCEDCONCEPTS
11
Digital Communications: introduction
COMMUNICATIONTHEORY
COMMUNICATIONCIRCUITS
DIGITALCOMMUNICATIONS
RADIATION ANDRADIOCOMMUNICATION
MOBILECOMMUNICATIONS
COMMUNICATIONSYSTEMS
BASICCONCEPTS
ADVANCEDCONCEPTS
12
Digital Communications: introduction
● Basic texts:
– Bernard Sklar, Digital Communications, 2001, Prentice Hall (Chapter 1).
– Simon Haykin, Communication Systems, 2001, Wiley (Background and preview).
– John G. Proakis, Digital Communications, 2008, McGraw-Hill (Chapter 1).
13
Digital Communications: introduction● Logical/functional organization of communications ⇒ layers
14
Digital Communications: introduction● Logical/functional organization of communications ⇒ layers
15
Digital Communications: introduction● Logical/functional organization of communications ⇒ layers
16
Digital Communications: introduction● Logical/functional organization of communications ⇒ layers
DataStream
17
Digital Communications: introduction● Logical/functional organization of communications ⇒ layers
DataStream
DataStream
18
Digital Communications: introduction● Logical/functional organization of communications ⇒ layers
MEDIUM
DataStream
DataStream
19
Digital Communications: introduction● Logical/functional organization of communications ⇒ layers
MEDIUM
DataStream
DataStream
20
Digital Communications: introduction● Logical/functional organization of communications ⇒ layers
PHY (1) PHY (1)
MEDIUM
DataStream
DataStream
21
Digital Communications: introduction● Logical/functional organization of communications ⇒ layers
PHY (1)
MAC (2)(<DLL)
PHY (1)
MAC (2)(<DLL)
MEDIUM
DataStream
DataStream
22
Digital Communications: introduction● Logical/functional organization of communications ⇒ layers
PHY (1)
MAC (2)(<DLL)
PHY (1)
MAC (2)(<DLL)
MEDIUM
DataStream
ControlControl
DataStream
23
Digital Communications: introduction● Logical/functional organization of communications ⇒ layers
PHY (1)
MAC (2)(<DLL)
PHY (1)
MAC (2)(<DLL)
MEDIUM
DataStream
ControlControl
DataStream
24
Digital Communications: introduction● Logical/functional organization of communications ⇒ layers
PHY (1)
MAC (2)(<DLL)
PHY (1)
MAC (2)(<DLL)
MEDIUM
DigitalCommunications
DataStream
ControlControl
DataStream
25
Digital Communications: introduction● Logical/functional organization of communications ⇒ layers
PHY (1)
MAC (2)(<DLL)
PHY (1)
MAC (2)(<DLL)
MEDIUM
Telematics
DigitalCommunications
DataStream
ControlControl
DataStream
26
Digital Communications: introduction
● Before proceeding further...– All 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...
27
Digital Communications: introduction
● Before proceeding further...– All 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...
?
28
Digital Communications: introduction
● Before proceeding further...– All 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
!
29
Digital Communications: introduction● What are the main functions carried out at the physical layer?
30
Digital Communications: introduction● What are the main functions carried out at the physical layer?
31
Digital Communications: introduction● What are the main functions carried out at the physical layer?
WIFI CARD inADSL modem
32
Digital Communications: introduction● What are the main functions carried out at the physical layer?
WIFI CARD inADSL modem
Radio frequency -RF(analog)
33
Digital Communications: introduction● What are the main functions carried out at the physical layer?
WIFI CARD inADSL modem
Radio frequency -RF(analog)
Upperlayers (2,3...)
34
Digital Communications: introduction● What are the main functions carried out at the physical layer?
WIFI CARD inADSL modem
Radio frequency -RF(analog)
Base-band
(digital)
Upperlayers (2,3...)
35
Digital Communications: introduction● What are the main functions carried out at the physical layer?
WIFI CARD inADSL modem
Radio frequency -RF(analog)
Base-band
(digital)
Upperlayers (2,3...)
● Adaptation to the medium.● Information protection.● Sharing resources.● Signal generation.● Interface between RF and upper
layers.● Evaluation and compensation of
channel distortions.● …...........................................................
36
Digital Communications: introduction● What are the main functions carried out at the physical layer?
WIFI CARD inADSL modem
Radio frequency -RF(analog)
Base-band
(digital)
Upperlayers (2,3...)
● Adaptation to the medium.● Information protection.● Sharing resources.● Signal generation.● Interface between RF and upper
layers.● Evaluation and compensation of
channel distortions.● …...........................................................
37
Digital Communications: introduction
● NOTE: conceptually separated operations.– Implementation may be done jointly instead of sequentially.
38
Digital Communications: introduction
● NOTE: conceptually separated operations.– Implementation may be done jointly instead of sequentially.
39
Digital Communications: introduction
● NOTE: conceptually separated operations.– Implementation may be done jointly instead of sequentially.
40
Digital Communications: introduction
● NOTE: conceptually separated operations.– Implementation may be done jointly instead of sequentially.
PHY (1) TX
41
Digital Communications: introduction
● NOTE: conceptually separated operations.– Implementation may be done jointly instead of sequentially.
Medium accessMedium access(Block 4)(Block 4)
PHY (1) TX
42
Digital Communications: introduction
● NOTE: conceptually separated operations.– Implementation may be done jointly instead of sequentially.
Medium accessMedium access(Block 4)(Block 4)
ModulationModulation(CT & Block 2)(CT & Block 2)
PHY (1) TX
43
Digital Communications: introduction
● NOTE: conceptually separated operations.– Implementation may be done jointly instead of sequentially.
Medium accessMedium access(Block 4)(Block 4)
ModulationModulation(CT & Block 2)(CT & Block 2)
Channel codingChannel coding(Block 3)(Block 3)
PHY (1) TX
44
Digital Communications: introduction
● NOTE: conceptually separated operations.– Implementation may be done jointly instead of sequentially.
Medium accessMedium access(Block 4)(Block 4)
ModulationModulation(CT & Block 2)(CT & Block 2)
Channel codingChannel coding(Block 3)(Block 3)
PHY (1) TX
45
Digital Communications: introduction
● NOTE: conceptually separated operations.– Implementation may be done jointly instead of sequentially.
Medium accessMedium access(Block 4)(Block 4)
ModulationModulation(CT & Block 2)(CT & Block 2)
Channel codingChannel coding(Block 3)(Block 3)
PHY (1) TX
CHANNEL1
Performance (1)
46
Digital Communications: introduction
● NOTE: conceptually separated operations.– Implementation may be done jointly instead of sequentially.
Medium accessMedium access(Block 4)(Block 4)
ModulationModulation(CT & Block 2)(CT & Block 2)
Channel codingChannel coding(Block 3)(Block 3)
PHY (1) TX
CHANNEL1
Performance (1)
47
Digital Communications: introduction
● NOTE: conceptually separated operations.– Implementation may be done jointly instead of sequentially.
Medium accessMedium access(Block 4)(Block 4)
ModulationModulation(CT & Block 2)(CT & Block 2)
Channel codingChannel coding(Block 3)(Block 3)
PHY (1) TX
CHANNEL1
Performance (1)
CHANNEL2
Performance (2)
48
Digital Communications: introduction
● NOTE: conceptually separated operations.– Implementation may be done jointly instead of sequentially.
Medium accessMedium access(Block 4)(Block 4)
ModulationModulation(CT & Block 2)(CT & Block 2)
Channel codingChannel coding(Block 3)(Block 3)
PHY (1) TX
CHANNEL1
Performance (1)
CHANNEL2
Performance (2)
49
Digital Communications: introduction
● NOTE: conceptually separated operations.– Implementation may be done jointly instead of sequentially.
Medium accessMedium access(Block 4)(Block 4)
ModulationModulation(CT & Block 2)(CT & Block 2)
Channel codingChannel coding(Block 3)(Block 3)
PHY (1) TX
CHANNEL1
Performance (1)
CHANNEL2
Performance (2)
CHANNEL3
Performance (3)
50
Digital Communications: introduction
● NOTE: conceptually separated operations.– Implementation may be done jointly instead of sequentially.
Medium accessMedium access(Block 4)(Block 4)
ModulationModulation(CT & Block 2)(CT & Block 2)
Channel codingChannel coding(Block 3)(Block 3)
PHY (1) TX
CHANNEL1
Performance (1)
CHANNEL2
Performance (2)
CHANNEL3
Performance (3) Design & evaluation:Information Theory (Block 2)
51
Digital Communications: introduction
● NOTE: conceptually separated operations.– Implementation may be done jointly instead of sequentially.
52
Digital Communications: introduction
● NOTE: conceptually separated operations.– Implementation may be done jointly instead of sequentially.
53
Digital Communications: introduction
● NOTE: conceptually separated operations.– Implementation may be done jointly instead of sequentially.
54
Digital Communications: introduction
● NOTE: conceptually separated operations.– Implementation may be done jointly instead of sequentially.
PHY (1) RX
55
Digital Communications: introduction
● NOTE: conceptually separated operations.– Implementation may be done jointly instead of sequentially.
Medium accessMedium access(Block 4)(Block 4)
PHY (1) RX
56
Digital Communications: introduction
● NOTE: conceptually separated operations.– Implementation may be done jointly instead of sequentially.
Medium accessMedium access(Block 4)(Block 4)
DemodulationDemodulation(CT & Block 2)(CT & Block 2)
PHY (1) RX
57
Digital Communications: introduction
● NOTE: conceptually separated operations.– Implementation may be done jointly instead of sequentially.
Medium accessMedium access(Block 4)(Block 4)
DemodulationDemodulation(CT & Block 2)(CT & Block 2)
ChannelChanneldecodingdecoding(Block 3)(Block 3)
PHY (1) RX
58
Digital Communications: introduction
● NOTE: conceptually separated operations.– Implementation may be done jointly instead of sequentially.
Medium accessMedium access(Block 4)(Block 4)
DemodulationDemodulation(CT & Block 2)(CT & Block 2)
ChannelChanneldecodingdecoding(Block 3)(Block 3)
PHY (1) RX
59
Digital Communications: introduction
● NOTE: conceptually separated operations.– Implementation may be done jointly instead of sequentially.
Medium accessMedium access(Block 4)(Block 4)
DemodulationDemodulation(CT & Block 2)(CT & Block 2)
ChannelChanneldecodingdecoding(Block 3)(Block 3)
PHY (1) RX
CHANNEL1
Performance (1)
60
Digital Communications: introduction
● NOTE: conceptually separated operations.– Implementation may be done jointly instead of sequentially.
Medium accessMedium access(Block 4)(Block 4)
DemodulationDemodulation(CT & Block 2)(CT & Block 2)
ChannelChanneldecodingdecoding(Block 3)(Block 3)
PHY (1) RX
CHANNEL1
Performance (1)
61
Digital Communications: introduction
● NOTE: conceptually separated operations.– Implementation may be done jointly instead of sequentially.
Medium accessMedium access(Block 4)(Block 4)
DemodulationDemodulation(CT & Block 2)(CT & Block 2)
ChannelChanneldecodingdecoding(Block 3)(Block 3)
PHY (1) RX
CHANNEL2
Performance (2)
CHANNEL1
Performance (1)
62
Digital Communications: introduction
● NOTE: conceptually separated operations.– Implementation may be done jointly instead of sequentially.
Medium accessMedium access(Block 4)(Block 4)
DemodulationDemodulation(CT & Block 2)(CT & Block 2)
ChannelChanneldecodingdecoding(Block 3)(Block 3)
PHY (1) RX
CHANNEL2
Performance (2)
CHANNEL1
Performance (1)
63
Digital Communications: introduction
● NOTE: conceptually separated operations.– Implementation may be done jointly instead of sequentially.
Medium accessMedium access(Block 4)(Block 4)
DemodulationDemodulation(CT & Block 2)(CT & Block 2)
ChannelChanneldecodingdecoding(Block 3)(Block 3)
PHY (1) RX
CHANNEL2
Performance (2)
CHANNEL1
Performance (1)
CHANNEL3
Performance (3)
64
Digital Communications: introduction
● NOTE: conceptually separated operations.– Implementation may be done jointly instead of sequentially.
Medium accessMedium access(Block 4)(Block 4)
DemodulationDemodulation(CT & Block 2)(CT & Block 2)
ChannelChanneldecodingdecoding(Block 3)(Block 3)
PHY (1) RX
CHANNEL2
Performance (2)
CHANNEL1
Performance (1)
CHANNEL3
Performance (3)Design & evaluation:Information Theory (Block 2)
65
Digital Communications: introduction● Additional operations at the PHY.
Source
Destination
66
Digital Communications: introduction● Additional operations at the PHY.
Medium accessMedium access(Block 4)(Block 4)
ModulationModulation(CT & Block 2)(CT & Block 2)
Channel codingChannel coding(Block 3)(Block 3)
PHY (1) TX
Source
Destination
67
Digital Communications: introduction● Additional operations at the PHY.
Medium accessMedium access(Block 4)(Block 4)
ModulationModulation(CT & Block 2)(CT & Block 2)
Channel codingChannel coding(Block 3)(Block 3)
PHY (1) TX
Encryption Source
Destination
68
Digital Communications: introduction● Additional operations at the PHY.
Medium accessMedium access(Block 4)(Block 4)
ModulationModulation(CT & Block 2)(CT & Block 2)
Channel codingChannel coding(Block 3)(Block 3)
PHY (1) TX
EncryptionSourcecoding Source
Destination
69
Digital Communications: introduction● Additional operations at the PHY.
Medium accessMedium access(Block 4)(Block 4)
ModulationModulation(CT & Block 2)(CT & Block 2)
Channel codingChannel coding(Block 3)(Block 3)
PHY (1) TX
DistortionNoise
LimitationsEncryption
Sourcecoding Source
Destination
70
Digital Communications: introduction● Additional operations at the PHY.
Medium accessMedium access(Block 4)(Block 4)
ModulationModulation(CT & Block 2)(CT & Block 2)
Channel codingChannel coding(Block 3)(Block 3)
PHY (1) TX
DistortionNoise
Limitations
Medium accessMedium access(Block 4)(Block 4)
DemodulationDemodulation(CT & Block 2)(CT & Block 2)
ChannelChanneldecodingdecoding(Block 3)(Block 3)
PHY (1) RX
EncryptionSourcecoding Source
Destination
71
Digital Communications: introduction● Additional operations at the PHY.
Medium accessMedium access(Block 4)(Block 4)
ModulationModulation(CT & Block 2)(CT & Block 2)
Channel codingChannel coding(Block 3)(Block 3)
PHY (1) TX
DistortionNoise
Limitations
Medium accessMedium access(Block 4)(Block 4)
DemodulationDemodulation(CT & Block 2)(CT & Block 2)
ChannelChanneldecodingdecoding(Block 3)(Block 3)
PHY (1) RX
EncryptionSourcecoding
Decryption
Source
Destination
72
Digital Communications: introduction● Additional operations at the PHY.
Medium accessMedium access(Block 4)(Block 4)
ModulationModulation(CT & Block 2)(CT & Block 2)
Channel codingChannel coding(Block 3)(Block 3)
PHY (1) TX
DistortionNoise
Limitations
Medium accessMedium access(Block 4)(Block 4)
DemodulationDemodulation(CT & Block 2)(CT & Block 2)
ChannelChanneldecodingdecoding(Block 3)(Block 3)
PHY (1) RX
EncryptionSourcecoding
DecryptionSource
decoding
Source
Destination
73
Digital Communications: introduction● Additional operations at the PHY.
Medium accessMedium access(Block 4)(Block 4)
ModulationModulation(CT & Block 2)(CT & Block 2)
Channel codingChannel coding(Block 3)(Block 3)
PHY (1) TX
DistortionNoise
Limitations
Medium accessMedium access(Block 4)(Block 4)
DemodulationDemodulation(CT & Block 2)(CT & Block 2)
ChannelChanneldecodingdecoding(Block 3)(Block 3)
PHY (1) RX
EncryptionSourcecoding
DecryptionSource
decoding
Source
Destination
74
Digital Communications: introduction● Additional operations at the PHY.
Medium accessMedium access(Block 4)(Block 4)
ModulationModulation(CT & Block 2)(CT & Block 2)
Channel codingChannel coding(Block 3)(Block 3)
PHY (1) TX
DistortionNoise
Limitations
Medium accessMedium access(Block 4)(Block 4)
DemodulationDemodulation(CT & Block 2)(CT & Block 2)
ChannelChanneldecodingdecoding(Block 3)(Block 3)
PHY (1) RX
EncryptionSourcecoding
DecryptionSource
decoding
Source
Destination
Block 2
75
Digital Communications: introduction● Additional operations at the PHY.
Medium accessMedium access(Block 4)(Block 4)
ModulationModulation(CT & Block 2)(CT & Block 2)
Channel codingChannel coding(Block 3)(Block 3)
PHY (1) TX
DistortionNoise
Limitations
Medium accessMedium access(Block 4)(Block 4)
DemodulationDemodulation(CT & Block 2)(CT & Block 2)
ChannelChanneldecodingdecoding(Block 3)(Block 3)
PHY (1) RX
EncryptionSourcecoding
DecryptionSource
decoding
Source
Destination
Block 2
76
Digital Communications: introduction● Additional operations at the PHY.
Medium accessMedium access(Block 4)(Block 4)
ModulationModulation(CT & Block 2)(CT & Block 2)
Channel codingChannel coding(Block 3)(Block 3)
PHY (1) TX
DistortionNoise
Limitations
Medium accessMedium access(Block 4)(Block 4)
DemodulationDemodulation(CT & Block 2)(CT & Block 2)
ChannelChanneldecodingdecoding(Block 3)(Block 3)
PHY (1) RX
EncryptionSourcecoding
DecryptionSource
decoding
Source
Destination
Block 2
Bas
ic h
ypo
thes
is:
equ
ipro
bab
le b
inar
y se
qu
ence
P(b
=0)
=P
(b=
1)=
0.5
77
Digital Communications: introduction● Design and performance criteria/parameters.
– Already known for those familiar with Comunication Theory.
– They are evaluated for each level/layer, point to point.
– Basic issue: limitations and tradeoffs → optimization.
78
Digital Communications: introduction● Design and performance criteria/parameters.
– 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
79
Digital Communications: introduction● Design and performance criteria/parameters.
– 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
80
Digital Communications: introduction● Design and performance criteria/parameters.
– 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
81
Digital Communications: introduction● Design and performance criteria/parameters.
– 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
Transmissionrate
82
Digital Communications: introduction● Design and performance criteria/parameters.
– 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
Transmissionrate
83
Digital Communications: introduction● Design and performance criteria/parameters.
– 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
Transmissionrate
Errorprobability
84
Digital Communications: introduction● Design and performance criteria/parameters.
– 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
Transmissionrate
Errorprobability
DistortionInterference
85
Digital Communications: introduction
86
MEDIUM
Digital Communications: introduction
Medium accessMedium access(TX)(TX)
Medium accessMedium access(RX)(RX)
87
MEDIUM
Digital Communications: introduction
Medium accessMedium access(TX)(TX)
Medium accessMedium access(RX)(RX)
Rmax
________
SNR____
Allowedinterference
____
Reliability____
BWmax
____
Pmax
88
MEDIUM
Digital Communications: introduction
Medium accessMedium access(TX)(TX)
Medium accessMedium access(RX)(RX)
Rmax
________
SNR____
Allowedinterference
____
Reliability____
BWmax
____
Pmax
R1 SNR
1 BW
1...
89
MEDIUM
Digital Communications: introduction
Medium accessMedium access(TX)(TX)
Medium accessMedium access(RX)(RX)
Rmax
________
SNR____
Allowedinterference
____
Reliability____
BWmax
____
Pmax
R2 SNR
2 BW
2...
R1 SNR
1 BW
1...
90
MEDIUM
Digital Communications: introduction
Medium accessMedium access(TX)(TX)
Medium accessMedium access(RX)(RX)
Rmax
________
SNR____
Allowedinterference
____
Reliability____
BWmax
____
Pmax
…...
...
R2 SNR
2 BW
2...
R1 SNR
1 BW
1...
Rn SNR
n BW
n...
91
MEDIUM
Digital Communications: introduction
Medium accessMedium access(TX)(TX)
Medium accessMedium access(RX)(RX)
Rmax
________
SNR____
Allowedinterference
____
Reliability____
BWmax
____
Pmax
…...
...
R2 SNR
2 BW
2...
R1 SNR
1 BW
1...
Rn SNR
n BW
n...
…......
R'2 SNR'
2 BW'
2...
R'1 SNR'
1 BW'
1...
R'n SNR'
n BW'
n...
92
MEDIUM
Digital Communications: introduction
Medium accessMedium access(TX)(TX)
Medium accessMedium access(RX)(RX)
Rmax
________
SNR____
Allowedinterference
____
Reliability____
BWmax
____
Pmax
…...
...
R2 SNR
2 BW
2...
R1 SNR
1 BW
1...
Rn SNR
n BW
n...
…......
R'2 SNR'
2 BW'
2...
R'1 SNR'
1 BW'
1...
R'n SNR'
n BW'
n...
SHARE ANDMANAGELIMITED
RESOURCES
93
MEDIUM
Digital Communications: introduction
Medium accessMedium access(TX)(TX)
Medium accessMedium access(RX)(RX)
Rmax
________
SNR____
Allowedinterference
____
Reliability____
BWmax
____
Pmax
…...
...
R2 SNR
2 BW
2...
R1 SNR
1 BW
1...
Rn SNR
n BW
n...
…......
R'2 SNR'
2 BW'
2...
R'1 SNR'
1 BW'
1...
R'n SNR'
n BW'
n...
SHARE ANDMANAGELIMITED
RESOURCES
InformationTheory
94
Digital Communications: introduction
95
Digital Communications: introduction
ModulationModulation(TX)(TX)
DemodulationDemodulation(RX)(RX)
96
CH
AN
NE
L
Digital Communications: introduction
ModulationModulation(TX)(TX)
DemodulationDemodulation(RX)(RX)
97
CH
AN
NE
L
Digital Communications: introduction
ModulationModulation(TX)(TX)
DemodulationDemodulation(RX)(RX) R
mod
________
SNR____
Ps(e)
____
BWmod
____
Pmod
98
CH
AN
NE
L
Digital Communications: introduction
ModulationModulation(TX)(TX)
DemodulationDemodulation(RX)(RX) R
mod
________
SNR____
Ps(e)
____
BWmod
____
Pmod
99
CH
AN
NE
L
Digital Communications: introduction
ModulationModulation(TX)(TX)
DemodulationDemodulation(RX)(RX) R
mod
________
SNR____
Ps(e)
____
BWmod
____
Pmod
100
CH
AN
NE
L
Digital Communications: introduction
ModulationModulation(TX)(TX)
DemodulationDemodulation(RX)(RX) R
mod
________
SNR____
Ps(e)
____
BWmod
____
Pmod
Pb(e)
_____
Eb/N0_____
Rb
101
CH
AN
NE
L
Digital Communications: introduction
ModulationModulation(TX)(TX)
DemodulationDemodulation(RX)(RX) R
mod
________
SNR____
Ps(e)
____
BWmod
____
Pmod
Pb(e)
_____
Eb/N0_____
Rb
ADAPT SIGNALSTO THE CHANNEL
AND IMPROVEPERFORMANCE
102
CH
AN
NE
L
Digital Communications: introduction
ModulationModulation(TX)(TX)
DemodulationDemodulation(RX)(RX) R
mod
________
SNR____
Ps(e)
____
BWmod
____
Pmod
Pb(e)
_____
Eb/N0_____
Rb
ADAPT SIGNALSTO THE CHANNEL
AND IMPROVEPERFORMANCE
InformationTheory
103
Digital Communications: introduction
104
Digital Communications: introduction
Channel codingChannel coding(TX)(TX)
ChannelChanneldecodingdecoding
(RX)(RX)
105
CH
AN
NE
L
Digital Communications: introduction
Channel codingChannel coding(TX)(TX)
ChannelChanneldecodingdecoding
(RX)(RX)
106
CH
AN
NE
L
Digital Communications: introduction
Channel codingChannel coding(TX)(TX)
ChannelChanneldecodingdecoding
(RX)(RX)
Pb(e)
________
Eb/N0(out)____
Rb
107
CH
AN
NE
L
Digital Communications: introduction
Channel codingChannel coding(TX)(TX)
ChannelChanneldecodingdecoding
(RX)(RX)
Pb(e)
________
Eb/N0(out)____
Rb
108
CH
AN
NE
L
Digital Communications: introduction
Channel codingChannel coding(TX)(TX)
ChannelChanneldecodingdecoding
(RX)(RX)
Pb(e)
________
Eb/N0(out)____
Rb
109
CH
AN
NE
L
Digital Communications: introduction
Channel codingChannel coding(TX)(TX)
ChannelChanneldecodingdecoding
(RX)(RX)
Pb(e)
________
Eb/N0(out)____
Rb
P'b(e)<P
b(e)
_____
Eb/N0(in)_____
R'b<R
b
110
CH
AN
NE
L
Digital Communications: introduction
Channel codingChannel coding(TX)(TX)
ChannelChanneldecodingdecoding
(RX)(RX)
Pb(e)
________
Eb/N0(out)____
Rb
P'b(e)<P
b(e)
_____
Eb/N0(in)_____
R'b<R
b
PROTECTINFORMATION
INTEGRITYAT THE COST
OF DATA RATE
111
CH
AN
NE
L
Digital Communications: introduction
Channel codingChannel coding(TX)(TX)
ChannelChanneldecodingdecoding
(RX)(RX)
Pb(e)
________
Eb/N0(out)____
Rb
P'b(e)<P
b(e)
_____
Eb/N0(in)_____
R'b<R
b
PROTECTINFORMATION
INTEGRITYAT THE COST
OF DATA RATEInformation
Theory
112
Digital Communications: introduction
● Example: WiFi standard(public access: http://standards.ieee.org/getieee802/download/802.11-2007.pdf )
113
Digital Communications: introduction
● Example: WiFi standard(public access: http://standards.ieee.org/getieee802/download/802.11-2007.pdf )
114
Digital Communications: introduction
● Example: WiFi standard(public access: http://standards.ieee.org/getieee802/download/802.11-2007.pdf )
115
Digital Communications: introduction
● Example: WiFi standard(public access: http://standards.ieee.org/getieee802/download/802.11-2007.pdf )
116
Digital Communications: introduction
● Medium access (channel identification).
117
Digital Communications: introduction
● Medium access (channel identification).
118
Digital Communications: introduction
● Medium access (channel identification).
119
Digital Communications: introduction
● Medium access (channel identification).
Signalgeneration
120
Digital Communications: introduction
● Medium access + modulation.
121
Digital Communications: introduction
● Medium access + modulation.
122
Digital Communications: introduction
● Medium access + modulation.
123
Digital Communications: introduction
● Medium access + modulation.
124
Digital Communications: introduction
● Medium access + modulation.
125
Digital Communications: introduction
● Medium access + modulation.Different modes
for resourcesharing
126
Digital Communications: introduction
● Medium access + modulation.Different modes
for resourcesharing
127
Digital Communications: introduction
● Modulation and channel coding.
128
Digital Communications: introduction
● Modulation and channel coding.
129
Digital Communications: introduction
● Modulation and channel coding.
130
Digital Communications: introduction
● Modulation and channel coding.
Modulator
131
Digital Communications: introduction
● Modulation and channel coding.
Modulator
132
Digital Communications: introduction
● Modulation and channel coding.
ModulatorChannelencoder
133
Digital Communications: introduction
● Modulation and channel coding.
ModulatorChannelencoder
134
Digital Communications: introduction
● Channel encoder.
135
Digital Communications: introduction
● Channel encoder.
136
Digital Communications: introduction
● Channel encoder.
137
Digital Communications: introduction
● Channel encoder.
138
Digital Communications: introduction
● Channel encoder.
Algebraicstructure
139
Digital Communications: introduction
● Channel encoder.
Algebraicstructure
140
Digital Communications: introduction
● Channel encoder.
Algebraicstructure
Implementation:finite-statemachine
141
Digital Communications: introduction● It is important to discern
– 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.
