Wireless Communication Course Instructor: Dr. Safdar Ali

Transcription

1 Wireless Communication Course Instructor: Dr. Safdar Ali

2 INTRODUCTION

3 BOOKS Text Book: William Stallings, Wireless Communications and Networks, Pearson Hall, 2002.

4 BOOKS Reference Books: Sumit Kasera, Nishit Narang, 3G Networks Architecture, Protocols, and Procedures,Tata McGraw-Hill Education, 2004.

5 COURSE EVALUATION Quiz: 10% Assignments: 20% Mid Term: 20% Final Exam: 50%

6 COURSE OUTLINE COURSE ORIENTATION Overview of the Course Course Policies Course Material TRANSMISSION FUNDAMENTALS Analog & Digital Transmissions Transmission Medium (Guided and Unguided) Channel Capacity Nyquist Theorem Shannon Theorem

7 COURSE OUTLINE COMMUNICATION NETWORKS LAN MAN WAN WLAN Circuit & Packet Switched Networks TCP PROTOCOL SUIT TCP/IP protocol stack IPV4 & IPV6

8 COURSE OUTLINE WIRELESS COMMUNICATION Generations 1G, 2G, 3G, 4G, Antennas & Wave Propagation Modes (Ground wave, Sky wave, Line-of-Sight) Atmospheric Absorption Multipath Propagation Refraction

9 COURSE OUTLINE MODULATION AND MULTIPLEXING TECHNIQUES Frequency Modulation (FM) Digital Transmission of Analog Signals Frequency Division Multiplexing (FDM) Time Division Multiplexing (TDM)

10 COURSE OUTLINE MULTIPLE ACCESS TECHNIQUES Difference between Multiplexing and Multiple Access Frequency Division Multiple Access (FDMA) Time Division Multiple Access (TDMA) TDMA Frame Structure GUEST LECTURE

11 COURSE OUTLINE Satellite Communication Geostationary Earth Orbit (GEO) Satellites Low Earth Orbiting (LEO) Satellites Medium Earth Orbiting (MEO) Satellites Satellite Footprint Satellite Network Configuration Satellite Capacity Allocation

12 COURSE OUTLINE MOBILE IP Overview of MIP MIPv4 MIPv6 CELLULAR NETWORKS GSM GPRS UMTS

13 COURSE OUTLINE Handoff in Wireless Mobile Networks Network-Controlled Handoff Mobile-Assisted Handoff Mobile-Controlled Handoff Hard Handoff Soft Handoff Softer Handoff Horizontal and Vertical Handoff Downward and Upward Vertical Handoff

14 Communication Networks

15 LEARNING OBJECTIVES & OUTCOMES Learning Objectives To provide an overview of various approaches to communication networking. Moreover, to introduce different networks types and diverse switching mechanisms. Learning Outcomes At the end of this section students will be able to understand different networking designs that includes LAN and WAN. Moreover, familiarize the concepts of packet and circuit switching mechanisms

16 TYPES OF COMMUNICATION NETWORKS Local area network (LAN) Wide area network (WAN)

17 LEASED LINE

18 SWITCHING NETWORK For transmission of data beyond a local area, communication is typically achieved by transmitting data from source to destination through a network of intermediate switching nodes. The switching nodes are not concerned with the content of the data; rather their purpose is to provide a switching facility that will move the data from node to node until they reach their destination.

19 SWITCHING NETWORK Information from station A intended for station F. Data is sent to node 4.

20 SWITCHING NETWORK It may then be routed via nodes 5 and 6 or nodes 7 and 6 to the destination.

21 SWITCHING NETWORK Some nodes connect only to other nodes (e.g., 5 and 7). Their sole task is the internal (to the network) switching of information.

22 SWITCHING NETWORK Node-station links are generally dedicated pointto-point links.

23 SWITCHING NETWORK Usually, the network is not fully connected; that is, there is not a direct link between every possible pair of nodes. However, it is always desirable to have more than one possible path through the network for each pair of stations. This enhances the reliability of the network.

24 SWITCHING NETWORK Two quite different technologies are used in wide area switched networks: Circuit switching and Packet switching. These two technologies differ in the way the nodes switch information from one link to another on the way from source to destination.

25 Circuit and Packet switching??

26 SWITCHING TECHNIQUES Circuit switching Dedicated communications path between two stations The most common example of circuit switching is the telephone network. Packet switching Each node determines next leg of transmission for each packet

27 CIRCUIT SWITCHING Station A wants to send data to station E.

28 PHASES OF CIRCUIT SWITCHING Circuit establishment An end to end circuit is established through switching nodes Information Transfer Information transmitted through the network Data may be analog voice, digitized voice, or binary data Circuit disconnect Circuit is terminated Each node deallocates dedicated resources

29 CONNECTION OVER A PUBLIC CIRCUIT- SWITCHING NETWORK Private Branch Exchange

30 Disadvantages?

31 CIRCUIT SWITCHING Can be inefficient Channel capacity dedicated for duration of connection even no data is being transferred. Utilization not 100% (either speaking or listening)

32 PACKET SWITCHING Data is transmitted in blocks, called packets A typical upper bound on packet length is 1000 octets (bytes). If a source has a longer message to send, the message is broken up into a series of packets

33 PACKET SWITCHING The control information, includes the information that the network requires in order to be able to route the packet through the network and deliver it to the intended destination.

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35 PACKET SWITCHING

36 Advantages?

37 PACKET SWITCHING ADVANTAGES Line efficiency is greater Many packets over time can dynamically share the same node to node link Unlike circuit-switching networks that block calls when traffic is heavy, packet-switching still accepts packets, but with increased delivery delay

38 Disadvantages?

39 PACKET SWITCHING DISADVANTAGES Overall packet delay can vary substantially This is referred to as jitter (critical for real time data services) Caused by differing packet sizes, routes taken and varying delay in the switches Each packet requires overhead information Includes destination and sequencing information Reduces communication capacity More processing required at each node