eee464lec01

EEE464Wireless Communication

SystemsLecture 1Introduction

Lecturer: Imran ShoaibLecturer: Imran Shoaib

http://groups.yahoo.com/group/wcs2010http://groups.yahoo.com/group/wcs2010

Course Information• Instructor:

Imran Shoaib• Office:

315, (Floor 3, EE building)• E-mail:

[email protected]• Office Hours:

Drop in or by appointment• Pre-requisites:

EEE314 – Data Communications and Computer Networks

EEE463 – Antennas and Radio Wave Propagation• Class Homepage:

http://groups.yahoo.com/group/wcs2010

2

Course Information (cont.)

• Textbook(s):• Wireless Communications, Andrea Goldsmith, Cambridge

University Press, 2005.• Wireless Communications: Principles and Practice,

Theodore S. Rappaport, 2nd ed., Prentice Hall, 2002.

• Reference Textbook(s):• Mobile Wireless Communications, M. Schwartz, Cambridge

University Press, 2005.• Modern Wireless Communications, S. Haykin and M.

Moher, Prentice Hall, 2005.• Antennas and Propagation for Wireless Communication

Systems, Simon Saunders and Alejandro Aragon Zavala, 2nd rev. Ed., Wiley, 2007.

3

Course ContentLecture # Topics covered

1 Introduction to Wireless Communication Systems.

2 Fundamentals Review.• Signals and Systems.• Analog Communication Systems.• Digital Communication Systems.• Data Communications and Wireless Networks.

3 – 6 The Cellular Concept.• Frequency Reuse.• Channel Assignment Strategies.• Handoff Strategies.• Interference and System Capacity.• Trunking and Grade of Service.• Improving Coverage and Capacity in Cellular Systems.

7 – 9 Radio Signal Propagation – Path Loss Modeling.• Basic Propagation Mechanisms: Reflection, Diffraction and Scattering.• Definition of Path Loss.• Free-space Propagation Model.• Two-ray Propagation Model.• Empirical and Physical Models for Macro- and Pico- cells.• Ray Tracing and Site Specific Modeling.

4

Course Content (cont.)

Lecture # Topics covered

10 Radio Signal Propagation – Shadowing.• Introduction.• Statistical and Physical Characterization.• Impact on Coverage and Capacity.

11 Radio Signal Propagation – Narrowband Fast Fading.• Introduction.• Baseband Channel Representation.• AWGN Channel.• Narrowband Fading Channel.• Physical Basis of Fast Fading: Rayleigh and Rician Characterization.• 2nd order statistics: Doppler Effect, Level-crossing Rate, Average Fade Duration.

12 Radio Signal Propagation – Wideband Fast Fading.• Introduction.• Effects of Wideband Fading.• Wideband Channel Model.• Power Delay Profile.• Wideband Channel Parameters.• Overcoming Wideband Channel Impairments.

13 Multiple Access Methods – FDMA, TDMA, CDMA, SDMA.

5



14 Equalization.• Introduction.• Linear Equalizers.• Non-linear Equalizers.• Adaptive Equalization.

15 Diversity.• Introduction.• Micro- and Macro- Diversity.• Combining Methods.

16 OFDM.• What is OFDM? (basic definition)• Why OFDM? (motivation)• How can we transmit via OFDM?• When/Where is OFDM used? (history & use)• OFDM Advantages and Disadvantages.

17 Existing Wireless Systems – AMPS & GSM.• Introduction.• Structure and Operation of AMPS.• Security Issues with 1G.• GSM Evolution.

6



17 (continued)• Infrastructure and Radio Specifications.• Operation of GSM.• Security and Authentication.

18 SMS, GPRS, EDGE.• Introduction.• System Architecture.• Impact on Existing Cellular Networks.• Evolutionary Benefits.

19 Existing Wireless Systems – IS-95.• Introduction.• CDMA Evolution.• IS-95 (CDMAone).• CDMA2000.

20 Existing Wireless Systems – UMTS.• Introduction to 3G Systems: IMT-2000 Family.• Universal Mobile Telecommunications System (UMTS): Network Architecture.• Domains and Interfaces, Handover Types in UMTS/GSM.• Key Features in Future Mobile and Wireless Networks.

7



21 Wireless Local Area Networks – IEEE802.11.• History and Development.• 802.11 Architecture Overview.• 802.11 Layer Architecture and Functions.• IEEE802.11 a/b/g/n standards.• IEEE802.11 Handoff Management.

22 Wireless Personal Area Networks – Bluetooth.• What is Bluetooth?• Radio Specifications.• Architecture Overview.• Connection Management.

23 Wireless Local Loops.• Introduction to WLL.• MMDS / LMDS.• IEEE802.16 Protocols.• WiMAX.

24 Evolving Wireless Systems – HSPA.• Introduction to High Speed Packet Access.• High Speed Downlink Packet Access (HSDPA).• High Speed Uplink Packet Access (HSUPA).

8



25 Beyond 3G – LTE.• History and Development.• Some Key LTE Technologies, including OFDMA and SC-FDMA.• The 3GPP LTE Standard.• Mobile WiMAX Standard Summary.• LTE and Mobile WiMAX Comparison.

26 – 27 MIMO Wireless Communications.• History of the Concept.• The Need of Multiple Antennas.• Benefits of MIMO Technology.• MIMO Channel Model and Capacity.

28 Seminar – Latest Trends in Cellular Radio and Personal Communications.

29 Seminar – Special Topics in Wireless Communications.

30 Course Review.

9

Grading Policy (maximum 100 marks)

10

• Assignments10%• Quiz 15% (a maximum of 6 marks shall be

given to the class project1)• Sessional-1 10%• Sessional-2 15%• Terminal Exam 50%

1Class Project:A seminar followed by a formal report on the “Latest trends in Cellular Radio and Personal Communications”. Groups of three are allowed.

Class Project (maximum 6 marks)

11

List of topics

• Femtocells.• Vertical Handoff.• The Significance of OFDM.• Wireless Body Area Networks.• Wireless Personal Area Networks.• Mobile Ad Hoc Networks.• IEEE and ETSI Wireless Standards.• WiMAX: Architecture and Specifications.• Universal Mobile Telecommunication System

(UMTS).• 4G Mobile Broadband.

What is wireless communication?• Any form of communication that does not require

the transmitter and receiver to be in physical contact.

• Mode of transfer of information over a distance without the use of electrical wires.

• The term “wireless” should not be confused with the term “cordless”, which is a subclass of wireless.

12

Why wireless communication?• User mobility – tetherless connectivity• Reduced infrastructure cost – reduced cabling• Flexibility – stay connected anywhere anytime• Portable devices – small volume, light enough to

be carried

13

General Terms involved in Wireless Communication Systems• Mobile Station

• A station in the cellular radio service intended for use while in motion at unspecified locations. These may be hand-held personal units (portables) or installed in vehicles (mobiles).

• Base Station• A fixed station in a mobile radio system used for radio communication

with mobile stations. Base stations are located at the centre or on the edge of a coverage region and consist of radio channels and transmitter and receiver antennas mounted on a tower.

• Transceiver• A device capable of simultaneously transmitting and receiving radio

signals.• Mobile Switching Center

• Switching center which coordinates the routing of calls in a large service area. In a cellular radio system, the MSC connects the cellular base stations and the mobiles to the PSTN. An MSC is also called a mobile telephone switching office (MTSO).

• Channel• A path over which electrical signals can pass. It can also be defined as the

medium of wave propagation.

14

General Terms involved in Wireless Communication Systems (cont.)• Control Channel

• Radio channel used for transmission of call setup, call request, call initiation, and other control purposes.

• Forward (Downlink) Channel• Radio channel used for transmission of information from base station

to the mobile.• Reverse (Uplink) Channel

• Radio channel used for transmission of information from the mobile to base station.

• Handoff• The process of transferring a mobile station from one channel or base

station to another.• Roamer

• A mobile station which operates in a service area other than that from which service has been subscribed.

• Subscriber• A user who pays subscription charges for using a mobile

communication system.

15

Challenges of Mobility• The use of radio channels demand methods of

sharing them – channel access.• The quality of the path – a more challenging

problem than with wires. Propagation media is a time-varying channel.

• Bandwidth: it is possible to add wires but no bandwidth. Spectrum is allocated by state rules so it is important to develop technologies that provide for channel reuse.

• Privacy and Security – a more difficult issue than with the wired communications.

• Others: battery power consumption, handoff, etc.

16

Degrees of Mobility• Walking users

• Low speed• Small roaming area• Usually uses high-bandwidth/low-latency access

• Vehicles• High speeds• Large roaming area• Usually uses low bandwidth/high-latency access• Uses sophisticated terminal equipment (cell

phones)

17

History of Wireless Communications(cont.)• 1896: Marconi

• first demonstration of wireless telegraphy• transmission of radio waves to a ship at sea 29km away• long wave transmission, high power req. (200kW and +)

• 1901: Marconi• Telegraph across the Atlantic ocean• close to 3000km hop

• 1907: Commercial transatlantic connections• huge ground stations (30 x 100 m antennas)

• 1915: Wireless telephony established• NY – San Francisco• Virginia and Paris

• 1920: Marconi• discovery of short waves (<100m)• reflection at the ionosphere• inexpensive and smaller sender and receiver, possible due to the

invention of the vacuum tube.• 1920s: radio broadcasting became popular• 1928: many TV broadcast trials

18

History of Wireless Communications (cont.)• 1930s: TV broadcasting deployment• 1946: first public mobile telephone service in US

• single cell system• 1960s: Bell Labs developed cellular concept

• brought mobile telephony to masses• 1960s: communications satellites launched• Late 1970s: technology advances enable affordable cellular

telephony• development of highly reliable, miniature, solid-state radio frequency

hardware• entering the modern cellular era

• 1974-1978: first field trial for cellular system• AMPS, Chicago

• 1983: 1st generation systems were deployed• Analog signals (AMPS, NMT, FDMA, FM)

• Early 1990s: 2nd generation systems were deployed• Digital signals (GSM, IS-136, IS-95, TDMA)

• 2000-01: 3rd generation systems were deployed• Korea and Japan (IMT2000 standard, UMTS, CDMA2000)

19

200?: 4G(LTE, UMB)

History of Wireless Communications (cont.)

20

cellular phones satellites wireless LANcordlessphones

1992:GSM

1994:DCS 1800

2001:IMT-2000

1987:CT1+

1982:Inmarsat-A

1992:Inmarsat-BInmarsat-M

1998:Iridium

1989:CT 2

1991:DECT 199x:

proprietary

1997:IEEE 802.11

1999:802.11b, Bluetooth

1988:Inmarsat-C

analogue

digital

1991:D-AMPS

1991:CDMA

1981:NMT 450

1986:NMT 900

1980:CT0

1984:CT1

1983:AMPS

1993:PDC

4G – fourth generation: when and how?

2000:GPRS

2000:IEEE 802.11a

200?:Fourth Generation

• Amateur radio

• Cellular systems

• Wireless LANs

• Satellite Systems

• Paging Systems

• Bluetooth headsets

• Ultra-wide band radios

• Zigbee radios

• Land-sea communication systems, etc...

Examples of Wireless Communication Systems

21

Figure. A typical cellular network

Examples of Wireless Communication Systems (cont.)

22

Satellite Network

Wireless Wide Area Networks

Wireless Metropolitan Area Networks

Wireless Local Area Networks

Wireless Personal Area Networks

Wireless Networks in comparison to Fixed Networks

23

• Higher loss-rates due to interference• emissions of, e.g., engines, lightening

• Restrictive regulations of frequencies• frequencies have to be coordinated, useful frequencies are

almost all occupied• Low transmission rates

• local some Mbits/s, regional currently, e.g., 53kbits/s with GSM/GPRS

• Higher delays, higher jitter• connection setup time with GSM in the second range, several

hundred milliseconds for other wireless systems• Lower security, simpler active attacking

• radio interface accessible to everyone, base station can be simulated, thus attracting calls from mobile phones

• Always shared medium• secure access mechanisms are very important

READING ASSIGNMENT!!

• Review concepts developed in• Analog and Digital Communications.• Data Communications and Computer Networks.

• Chapter 1 – Overview of Wireless Communications• Wireless Communications, Andrea Goldsmith,

Cambridge University Press, 2005.

24

eee464lec01

Documents