Electrical Communications Systems ECE.09.433 Spring 2019 Lecture 10a April 2, 2019 Shreekanth Mandayam ECE Department Rowan University http://engineering.rowan.edu/~shreek/spring19/ecomms/

Plan Digital Baseband Communications Pulse Amplitude Modulation Sampling Quantization TDM Standards T1 (DS-1) Line North American TDMA Hierarchy Line Encoding Data Processing & Data Communications Communications Networks Packet Switched Networks OSI 7-Layer Protocol Architecture TCP-IP Protocol Architecture

ECOMMS: Topics

Digital Communications Transceiver Anti- aliasing Filter Data Encryption Encoder Error Control Encoder Sampling Channel/ Line Encoder Quantization Source Encoder MUX Modulator ADC Analog i/p CODEC MODEM Multiple access channel Analog o/p Data Encryption Decoder Error Control Decoder Audio Amp Reconstruction/ DAC Source Decoder Equalization / Decision Circuits DEMUX Demod-ulator

Pulse Code Modulation (PCM) Standard for all digital communications Analog Signal Sample & Hold Digital Bitstream Quantize Encode PAM PCM

Pulse Amplitude Modulation: Flat-top Sampling -0.5 0.5 1 1.5 2 2.5 3 3.5 4 -6 -4 -2 6 8 time Analog PAM Matlab Demo: pam.m

Quantization Uniform Non-Uniform m-Law A-Law Mid-rise Mid-tread Matlab Demos: quantization.m pcm.m Mid-rise Mid-tread Mid-rise Mid-tread Matlab Demos: companding.m pcm_mucompand.m pcm_mucompand2.m pcm_acompand.m pcm_acompand2.m

Digital Communications Transceiver Anti- aliasing Filter Data Encryption Encoder Error Control Encoder Sampling Channel/ Line Encoder Quantization Source Encoder Modulator MUX ADC Analog i/p CODEC MODEM Multiple access channel Analog o/p Data Encryption Decoder Error Control Decoder Audio Amp Reconstruction/ DAC Source Decoder Equalization / Decision Circuits DEMUX Demod-ulator

Time Division Multiplexing Message 1 Quantize & Encode Message 2 Channel Message N Message 1 LPF Decode Message 2 LPF Message N LPF

T1-Line TDM Format 1 Frame = (24 Channels + F) = 125 ms Channel 1 1 8 7 6 5 4 3 2 Channel 2 1 8 7 6 5 4 3 2 Channel 24 1 8 7 6 5 4 3 2 F 193 bits Frame Sync Bit Even Frames: 0 0 1 1 1 0 Odd Frames: 1 0 1 0 1 0 Every Sixth Frame LSB (8th bit) is a Signaling bit Bipolar R-Z Line Encoding

North American TDMA Hierarchy 64 kbps 1 VF DS-0 1 1 7 DS-2 6.312 Mbps 96 VF 3rd M U X 1 6 DS-3 44.736 Mbps 672 VF 4th M U X 1 2 DS-4 274.176 Mbps 4032 VF 5th M U X 1 4 DS-1 1.544 Mbps 24 VF 2nd M U X 1st M U X 24 DS-5 560.160 Mbps 8064 VF Figure 3-40, p. 214 in Couch Table 3-8, p. 215 in Couch Table 3-9, p. 216 in Couch

Digital Communications Transceiver Anti- aliasing Filter Data Encryption Encoder Error Control Encoder Sampling Channel/ Line Encoder Quantization Source Encoder MUX Modulator ADC Analog i/p CODEC MODEM Multiple access channel Analog o/p Data Encryption Decoder Error Control Decoder Audio Amp Reconstruction/ DAC Source Decoder Equalization / Decision Circuits DEMUX Demod-ulator

Line Encoding Couch, p. 170 Couch, p. 165

Digital Communications Transceiver Anti- aliasing Filter Data Encryption Encoder Error Control Encoder Sampling Channel/ Line Encoder Quantization Source Encoder Modulator MUX ADC Analog i/p CODEC MODEM Multiple access channel Analog o/p Data Encryption Decoder Error Control Decoder Audio Amp Reconstruction/ DAC Source Decoder Equalization / Decision Circuits DEMUX Demod-ulator

Digital Communication Paradigms Recall Digital Communication Paradigms Multiplexer Message 2 Message 3 Message 1 1 2 3 S Demultiplexer Circuit Switching Sync bits Packet Switching Header bits Packetizing Message 2 Message 3 Message 1 1 H 2 3 Depacket-izing

Communications Networking Router Step 1: Step 2: Step 3: …….. Protocol Sender Medium Receiver Message

A 3-Layer Protocol Architecture File transfer application Communications service module Network access module Files and file transfer commands File transfer application Communications service module Network access module Comm related messages Comm network Computer 1 Computer 2

ISO OSI 7-Layer Model 7 Application 6 5 Presentation 4 3 Session 2 1 Physical Data Link Network Presentation Session Transport Application 7 6 5 4 3 2 1 Please Do Not Touch Steve’s Pet Alligator

TCP-IP Protocol Architecture Physical Network Access Internet Transport (host-to-host) Application TCP-IP Application Presentation Session Transport Network Data Link Physical OSI Hardware Firmware Software Operating system User space

TCP-IP Operation Example Network access protocol #1 Physical IP TCP Host A App X App Y Network access protocol #2 Physical IP TCP Host B App X App Y Port or Service access point (SAP) Logical connection (TCP) Global network address Subnetwork attachment point address Logical connection Router J IP NAP1 NAP2 Network 1 Network 2

TCP-IP Protocol Packet TCP header IP header Network header User Data Application Byte Stream TCP Segment IP Datagram Network Level Packet

IP Header 0 4 8 16 19 31 20 octets Version IHL Type of Service 0 4 8 16 19 31 Version IHL Type of Service Total Length Identification Flags Fragment Offset Time to Live Protocol Header Checksum Source Address Destination Address Options + Padding 20 octets

Acknowledgement Number TCP Header 0 4 10 16 31 Source Port Destination Port Sequence Number Acknowledgement Number Data Offset Reserved URG ACK PSH RST SYN FIN Window Checksum Urgent Pointer Options + Padding 20 octets

Summary