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Teletraffic Theory
Michael Logothetis

Introduction - The objectives of Teletraffic Engineering -The Nature of Teletraffic. Features of Teletraffic Systems. Modeling of Teletraffic Systems. Markov Property. Little's Theorem. Traffic from Terminals and Aggregated Traffic. Markovian Loss Systems. Markovian Delay Systems. Birth-Death Process. Multi-Dimensional Traffic Models - Trunk Reservation System. Restricted availability. Overflow System -Equivalent Random Theory. Design of Alternative Routing. Traffic Simulation. Computer Implementation of Basic Teletraffic Formulas. Queueing Networks and Operational Laws. Mean Value Analysis in Queueing Networks.

Broadband Networks
Michael Logothetis

Introduction – Recent Trends in Requirements for Telecommunication – Progress in Technology and in System Concept. Narrowband-ISDN and Broadband-ISDN Services. Transfer Modes – Circuit Switching – Multi-rate Circuit Switching – Fast Circuit Switching – Packet Switching – Fast Packet Switching – Asynchronous Transfer Mode (ATM) – Frame Relay – Switched Multi-Megabit Data Service (SMDS). B-ISDN Protocol Reference Model (PRM) – ATM PRM. ATM – An Overview. ATM Network Interfaces. Protocol Layers. ATM Cell Header Format. Connection Identifiers. VP/VC Assignment. Header Error Check (HEC). LAN Emulation. ATM Virtual LANs. IP Over ATM. Comparison of ATM with other Transfer Modes. Statistical Multiplexing. Resource management in ATM networks. Principles of Traffic and Congestion Control in ATM Networks. Principles of ATM Switching. SDH – The Synchronous Digital Hierarchy architecture of Transmission Systems. MPLS – Definition, Functions, Components: Label Switching Routers (LSRs), Label Edge Routers (LERs), Label Information Base (LIB), Forward Equivalence Class (FEC), Label-Switched Paths (LSPs), Labels, MPLS Label Format, Label Bindings, Label Creation, Label Spaces, Label Distribution, Label Distribution Protocol (LDP), Label Merging, Label Retention, Label Control, Signaling Mechanisms, Label Stack, Traffic Engineering, Constraint-based Routing (CR). EXAMPLE: MPLS NETWORK, Use of Labels.

Optical Networks – Architecture. Wavelength Division Multiplexing. Optical Time Division Multiplexing. Optical Switching. Optical Network Componets. Core/Backbone networks, Metropolitan Area Optical Networks and Optical Access Networks. Passive Optical Networks for Broadband Access.

Gigabit Ethernet Technology – Need for Gigabit Ethernet. Description of Gigabit Ethernet. Pros and cons of the Gigabit Ethernet.

Microwaves (old: Telecommunication Systems I)
Michael Logothetis

Theory of transmission lines: Introduction. The differential equations of the uniform transmission line. Uniform line parameters. Travelling waves. Input impedance of a transmission line. Standing wave patterns. Lossless lines. Transmission line charts. The Smith chart. Slotted line measurements. Crosstalk in short and long transmission lines.

Computer Communication Networks
Michael Logothetis
Computer Networks and the Internet.
Communication Protocol.
Open Systems Interconnection.
Why 5 Layers are enough?
The protocol layers stack of the
The Network Edge.
The Network Core.
Networks with Virtual Circuits and
Delay and Loss in Packet-Switched
Delay and Loss in Circuit-Switched
Elementary teletraffic theory
Application Layer (AL):
Principles of AL Protocols.
Services needed by an application.
Transport Layer (TL):
The goal.
The TL of the Internet.
Basic multiplexing/de-multiplexing
functions in TL.
The User Datagram Protocol (UDP)
(Segment structure, Checksum).
Principles of Reliable Data Transfer.
Stop & Wait protocol.
The Transport Control Protocol (TCP).
The TCP connection.
Round-Trip time.
Determination of the length of the
“Sequence Numbers” field.
Flow control.
Congestion Control.
Best Transmission Window Size.
Network Layer:
The goal.
The Service Model (Virtual Circuits –
Routing. Centralized and distributed
routing algorithms.
Hierarchical Routing.
The Internet Protocol (IP).
IPv4 addresses.
Subnets definition through subnet
Moving a Datagram from Source to
Destination: Addressing, Routing and
The ICMP Protocol.
Routing in the Internet.
Intra-Autonomous System Routing:
Inter-Autonomous System Routing:
Transition from IPv4 to IPv6.
Inside a Router.
Head of the Line Blocking.
Virtual Output Queues.
Data Link Layer (DLL):
The goal. The services.
Broadcast channels and PPP.
Adapters Communicating.
Error Detection and Error Corrections
MAC – Channel Partitioning Protocols:
– Random Access Protocols: Aloha,
Slotted Aloha, CSMA, CSMA/CD
(Ethernet). – Taking-Turns Protocols:
Polling – Token Pass.
Hubs, Bridges and Switches
(comparison with routers).
The LAN as a DLL protocol.

Communications Systems
Michael Logothetis

Introduction: Communication concept and model. Basic components and resources of communications systems. Analog and digital systems (Transmitter - Transmission Channel - Receiver - Distortion - Interference). Examples. Brief review of the evolution of communications systems.
Analog Transmission: Need of Modulation. Amplitude Modulation Systems. Demodulation. Angle modulation: Frequency and Phase Modulation. Demodulation of FM signals.
Effect of noise on Analog Transmission. The noise as a Stochastic Signal. Power Spectral Density. White Noise. Bandpass noise. Efficiency of the Amplitute Modulation Systems in the presence of noise. Efficiency of the Frequency Modulation Systems in the presence of noise. Pre-emphasis, De-emphasis. Comparison of FM - AM systems.
Digitazation of analog signals: Sampling theorem. Quantization of analog signals. Quantization noise.
Pulse Modulation: Pulse Amplitute Modulation (PAM), Pulse Duration Modulation (PDM / PWM), Pulse Position Modulation (PPM), Pulse-Coded Modulation (PCM). Efficiency of PCM in the presence of noise. PCM system of 1st and higher order.
Signal multiplexing: Orthogonal, Time Division Multiplexing (TDM), Frequency Division Multiplexing (FDM).
Digital Transmission: General: Symbol coding, Line coding, Transmission Rate, Error rate, Shannon-Hartley Theorem (Shannon's capacity). Spectral (bandwidth) efficiency.
Baseband digital transmission: Pulse transmission. Inter-Symbol Interference (ISI). Eye Pattern. 1st and 2nd Nyquist criteria. Filters of Rise Cosine. Transmission channel with Additive White Gaussian Noise. Equalizer and Matched Filter. Baseband transmission using M-ary PAM. Probability of error in the presence of Gaussian noise (use of Q-function).
Digital transmission with modulated carrier: Amplitute Shift Keying (ASK, On-Off Keying, OOK), Frequency Shitf Keying (FSK), Phase Shift Keying (PSK), Combined Phase and Amplitute Modulation (QAM), M-ary Phase Modulation (QPSK, 8PSK, 16PSK) and other M-ary modulations. Constellations.
Examples of communications systems.