Published on November 28, 2007
EE 551/451, Fall, 2006Communication Systems: EE 551/451, Fall, 2006 Communication Systems Zhu Han Department of Electrical and Computer Engineering Class 29 Dec. 7th, 2006 Statistics: Statistics Grade based on relative values and clusters. Do not be the outlier. Midterm mean 52.4 Project 1 mean 6.44 Project 2 mean 8.39 homework mean 8.16 Final Exam: Final Exam Exam: Tuesday, December 12th at 3:30 - 5:30 p.m. in ET314. 50% why questions and 5 big questions (10 point each) Nyguist sampling theory Line coding Pulse Shaping Digital modulation Coding theory For big questions: Home works and examples For concept questions: slides, if questions, come to my office or call me. Office hour, Friday, Monday from 9:30am to 5:00pm Email, phone 208-426-4059, during weekend for part-time Outline: Outline PSTN: basic phone services Connect to the backbone ISDN Cable Modem ADSL Hybrid Fiber Coax Backbone DS0, DS1, DS3, OC1, OC3, OC12, OC48, OC192… ATM Wireless: cellular phone, WLAN, WMAN,… Video: video standard, video on demand, HDTV Satellite communication and GPS Transmission media: twisted wires, coax, cable, radio… Public switched telephone network (PSTN): Public switched telephone network (PSTN) Major Components of the Public Switched Telephone Network (PSTN): Switching Offices, Transmission facilities, Customer Premise Equipment Switching Office CPE CPE Transmission Facilities Switching Office Integrated Services Digital Network (ISDN): Integrated Services Digital Network (ISDN) Telephone services -> Telecommunication services Used for voice, image and data Types of channels Bearer channel (B-channel=64 kb/s) clear pipe for data Delta channel (D-channel, 16 kb/s or 64 kb/s) call signaling information: who is calling type of call calling what number Service types Basic Rate Interface (2 B channels + 1 D channel) Primary Rate Interface (30 B channels + 1 D channel) 56 k Technology (modem connection): 56 k Technology (modem connection) Access server Modem Telephone switch Telephone switch ? Access server Modem Modem Digital line Analog line <= 33,6 kbps <= 56 kbps ISDN, E1,.. <= 33,6 kbps Asymmetrical Digital Subscriber Line ADSL: Asymmetrical Digital Subscriber Line ADSL ADSL is the #1 Broadband Choice in the World with over 60% market share ADSL is now available in every region of the world ADSL is capable of providing up to 50 Mbp, and supports voice, video and data. The new DSL network is IP-centric There is broad equipment interoperability and there are currently established test specifications for ADSL, ADSL2plus, SHDSL, and VDSL Finally, ADSL and home networking are a natural fit as DSL effectively supports multiple applications for multiple uses via each DSL connection. ADSL Networks: ADSL Networks ADSL 1.5 to 8Mbit/s 9.6 to 640kbit/s Broadband Network Internet Video Servers Live Broadcast Telephone Network ADSL Modem Structure: ADSL Modem Structure ADSL Modem POTS Filter Mbit/s kbit/s ADSL Modem POTS Filter POTS Linecard Mbit/s kbit/s Line Exchange End Customer End Cable Modem: Cable Modem A digital service offered by cable television companies Data Over Cable Service Interface Specifications (DOCSIS) Most common protocol used for cable modems Not a formal standard Offers vary (depends on the quality of cable plant) In theory: downstream: 27-55Mbps; upstream: 2-10 Mpbs Typical: downstream: 1.5 -2 Mbps; upstream 0.2 – 2 Mbps A few cable companies offer downstream services only Upstream communications using regular telephone lines Cable modems: use shared multipoint circuits All messages on the circuit heard by all computers on the circuit security issue 300 – 1000 customers per cable segment Basic Cable Modem Architecture: Basic Cable Modem Architecture Cable Company Distribution Hub Cable Splitter Customer Premises TV Cable Modem Hub Computer Computer Shared Coax Cable System Combiner Customer Premises Customer Premises TV Video Network Cable Modem Termination System Cable Company Fiber Node Optical/ Electrical Converter Downstream Upstream Router Cable Company Fiber Node Hybrid Fiber Coax: Hybrid Fiber Coax Fiber in the CATV Network: Fiber in the CATV Network Fiber Optic will increase quality, reliability, and operational savings. Fiber Optic is economically competitive in comparison with coaxial cable. Fiber Optic offers the opportunity of two-way services, fact that will increment revenues for the company. Fiber Optic networks are fully expandable, with large capacities to provide countless services. T Carrier System: T Carrier System Twisted Wire to Cable System Fiber Communication: Fiber Communication Asynchronous Transfer Mode (ATM): Asynchronous Transfer Mode (ATM) Designed by phone companies Single technology meant to handle Voice Video Data Intended as LAN or WAN End-to-end (application to application) Connection-oriented interface: Establish “connection” Send data Close connection Performance guarantees (statistical) Uses cell switching ATM Cell, Virtual Circuit: ATM Cell, Virtual Circuit ATM cell: 53 byte; 48 bytes of data and 5 bytes of header information Successes and failures of ATM : Successes and failures of ATM Goal: replacement for Internet ATM has proved very successful in the WAN scenario “We know that there will always be both brand-new and obsolescent link-layer technologies, particularly in the LAN area, and it is fair to assume that not all of them will fit neatly into the synchronous optical networking model that ATM was designed for. Therefore, some sort of protocol is needed to provide a unifying layer over both ATM and non-ATM link layers, and ATM itself cannot fill that role. Conveniently, we have this protocol called "IP" which already does that. Ergo, there is no point in implementing ATM at the network layer.” Gigabit Ethernet implementations (10Gbit-Ethernet, Metro Ethernet) will replace ATM as a technology of choice in new WAN implementions. Transmission Media: Transmission Media Wireless Communications: Wireless Communications Next Semester Cellular Phone WLAN: WIFI WMAN: WIMAX Radio System Propagation: Radio System Propagation Satellite Communications: Satellite Communications Large communication area. Any two places within the coverage of radio transmission by satellite can communicate with each other. Seldom effected by land disaster ( high reliability) Circuit can be started upon establishing earth station (prompt circuit starting) Can be received at many places simultaneously, and realize broadcast, multi-access communication economically( feature of multi-access) Very flexible circuit installment , can disperse over-centralized traffic at any time. One channel can be used in different directions or areas (multi-access connecting). GPS: GPS Just a timer, 24 satellite Calculation position Video Standard: Video Standard Two camps H261, H263, H264; MPEG1 (VCD), MPEG2 (DVD), MPEG4 Spacial Redundancy: JPEG Intraframe compression DCT compression + Huffman coding Temporal Redundancy Interframe compression Motion estimation Discrete Cosine Transform (DCT): Discrete Cosine Transform (DCT) 0 – black 255 – white DCT and Huffman Coding: DCT and Huffman Coding 0 – black 255 – white Motion Compensation: Motion Compensation I-Frame Independently reconstructed P-Frame Forward predicted from the last I-Frame or P-Frame B-Frame forward predicted and backward predicted from the last/next I-frame or P-frame Transmitted as - I P B B B P B B B Motion Prediction: Motion Prediction HDTV: HDTV 4-7 Mbps 25 - 27 Mbps Final Remarks: Final Remarks Student, teacher, competitor: Tent, ring, and wind Motivation for study: kayak upstream Interdisciplinary study Middle class for sure Viterbi: retired Dr. Jake Baker: well-known Rowan Atkinson: former BBC engineer Hope you have studied something and Wish you success. If so, do not forget BSU Questions?: Questions?