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IK2506 Advanced Communication Systems
• TEN1: 6 HEC. • INL1: 1,5 HEC.
– 3 Problem Assignments
• Required reading:– Carlson, B., et. al., Communication Systems,
McGrawHill, 2002.
• Course Webpage:– http://www.kth.se/student/program-kurser/
kurshemsidor/kurser-ict/cos/IK2506/HT09-1?l=en_UK
Teachers
• Anders Västberg (Examiner)– [email protected]– 08-790 44 55
• Svante Signell– [email protected]– 08-790 41 46
Supplementary rules for examination
• Rule 1: All group members are responsible for group assignments
• Rule 2: Document any help received and all sources used
• Rule 3: Do not copy the solutions of others• Rule 4: Be prepared to present your solution• Rule 5: Use the attendance list correctly
For more information, see KTH rules at:http://www.kth.se/dokument/student/student_rights.pdf
Mathematica and MATLAB
• Download the programs from:– http://progdist.ug.kth.se/public/
• General introduction to Mathematica– http://www.cos.ict.kth.se/~goeran/archives/Ma
thematica/Notebooks/General/
Carlson: Communication Systems
[Stallings., 2005]
Signals andSpectra
Signal Transmission and Filtering
AnalogModulation
Sampling andPulse
Modulation
AnalogCommunication
Systems
RandomSignals and
Noise
Noise in AnalogModulationSystems
DigitalModulation
Information Theory
and Channel Coding
COS Wireless Courses
IK2507 Wireless Communication Systems
IK2508 Wireless Transmission
IK2510 Wireless Networks
IK2506 Advanced Communication Systems
Signals, Systems and SpectraModulation, Stochastic Processes
Radio Propagation, Link Design and Diversity,Spectrum Resource Management
Data Transmission over Radio Channels,Error Control Coding for Radio Channels
Radio Resource Management forWireless Networks
IK2511 Wireless Network Project
Research Project
Course Aim
• Give the student the ability to analyze the design parameters of a communication system. That means that the student should be able to:– Explain the system structure of analogue and
digital communication systems– Use mathematical tools to analyse the
performance of communication systems– Use probability theory and stochastic processes
in communication system applications.
Communication Systems
• Main functionality: Information Transfer
• Can not cover all types of communication systems
• Can not cover the detailed implementation– Look at system level
Types of Communication Systems
• Analog Communication Systems– Analog message: “Physical quantity that
varies with time”
• Digital Communication Systems– Digital message: “Ordered sequence of
symbols selected from a finite set of discrete elements”
Communication Systems
Source of information
Informationsink
Transmitter
Channel
Receiver
Message signal
Estimate of message
signal
Transmitted signal
Received signal
[Ahlin et. al., 2006]
Basic Structure
• Transmitter– Modulation– Coding
• Transmission Channel– Loss or Attenuation– Distortion– Interference– Noise
• Receiver– Amplification– Demodulation and decoding– Filtering
Alteration of the Signal
• Loss or Attenuation– Can be compensated by amplification at the receiver
• Alteration of the Signal Shape– Distortion
• Disappears when the signal is turned off• Linear distortion may be corrected by the use of equalizers
(special filter).
– Interference• Contamination by other signals from human sources
– Noise• Contamination by signals from natural processes both
internal and external to the system
Types of Communication
• Simplex (SX)– One way communication
• Full-duplex (FDX)– Two way communication at the same time
• Half-duplex (HDX)– Two way communication, but not at the same
time.
Fundamental Physical Limitations
• Bandwidth– If a signal changes
rapidly in time, its frequency content or spectrum extends over a wide range, i.e. the signal has a large bandwidth
– Transmission bandwidth
• Noise– Thermal noise
MBC 2log2
)/1(log2 NSBC
Analog Communication System
Source of information
Signal Processing
Modulator RF-Stage
Channel
RF-StageInformation
sinkSignal
ProcessingDemodulator
[Slimane]
Modulation
• Modulating signal– Represent the message
• Carrier Wave– Waveform the suits the application
• Modulation is a reversible operation– Modulation – Demodulation
• Frequency translation
Modulation
• Modulation for Efficient Transmission– Antennas should have a dimension of at least 1/10 of
the wavelength of the radio signal• Modulation to Overcome Hardware Limitations
– Bandwidth should be at most 1/10 of the carrier frequency
• Modulation to Reduce Noise and Interference– Wideband noise reduction – Increase bandwidth to
reduce signal power• Modulation for Frequency Assignment• Modulation for Multiplexing
– Multiple Access
Digital Communication System
Source of Information
SourceEncoder
Modulator RF-Stage
Channel
RF-StageInformation
SinkSource
DecoderDemodulator
ChannelEncoder
DigitalModulator
ChannelDecoder
DigitalDemodulator
[Slimane]
Coding
• Modulation – Signal Processing Operation
• Coding – Symbol Processing Operation
• Encode – Decode
• Channel Coding
• Source Coding
decibels• The bel is a logarithmic unit of power ratios. One bel corresponds to an
increase of power by a factor of 10 relative to some reference power, Pref.
refbel P
PP 10][ log
refdB P
PP 10][ log10
• The bel is a large unit, so that decibel (dB) is almost always used:
• The above equation may also be used to express a ratio of voltages (or field strengths) provided that they appear across the same impedance (or in a medium with the same wave impedance):
refdB V
VV 10][ log20
[Saunders, 1999]
decibels
Unit Reference Power Application
dBW 1 W Absolute power
dBm 1 mW Absolute power
P [dbW] = P [dBm] - 30
dBV 1 V Absolute voltage, typically at the input terminals of a receiver
dB any Gain or loss of a network
dBV/m 1 V/m Electric field strength
dBi Power radiated by and isotropic reference antenna
Gain of an antenna
dBd Power radiated by a half-wave dipole
Gain of an antenna
0 dBd = 2.15 dBi
[Saunders, 1999]
Signals
• Deterministic Signals– Periodic Signals– Non-Periodic
• Stochastic Signals– Stationary– Non Stationary
