EE359 – Lecture 19 Outline Announcements Review of Last Lecture

Slides:

Advertisements

Similar presentations

IE 419/519 Wireless Networks Lecture Notes #6 Spread Spectrum.

Advertisements

Spread Spectrum Chapter 7.

Spread Spectrum Chapter 7. Spread Spectrum Input is fed into a channel encoder Produces analog signal with narrow bandwidth Signal is further modulated.

Time Division Frames PreambleInformation MessageGuard Time Frame (T f ) Slot 1Slot 2Slot 3Slot N... Header Synch Bits Control, Signaling CRC Info. Bits.

EE359 – Lecture 16 Outline Announcements: HW due Thurs., last HW will be posted Thurs., due 12/4 (no late HWs) Friday makeup lecture 9:30-10:45 in Gates.

Lecture 8: Spread Spectrum

EE360 – Lecture 2 Outline Announcements: Class mailing list: (subscribe Wireless network lunches:

EE360: Lecture 9 Outline Multiuser OFDM Announcements: Project abstract due next Friday Multiuser OFDM Adaptive Techniques “OFDM with adaptive subcarrier,

Spread Spectrum Input is fed into a channel encoder

William Stallings Data and Computer Communications 7th Edition

#7 1 Victor S. Frost Dan F. Servey Distinguished Professor Electrical Engineering and Computer Science University of Kansas 2335 Irving Hill Dr. Lawrence,

SPREAD SPECTRUM In spread spectrum (SS), we combine signals from different sources to fit into a larger bandwidth, but our goals are to prevent eavesdropping.

Wireless Communications: Lecture 2 Professor Andrea Goldsmith

II. Medium Access & Cellular Standards. TDMA/FDMA/CDMA.

1 CMPT 371 Data Communications and Networking Spread Spectrum.

Wireless communication channel

1 Lecture 9: Diversity Chapter 7 – Equalization, Diversity, and Coding.

Spread Spectrum Techniques

TYPES OF SS TECHNIQUES THE FUTURE LIES WITHIN. INTRODUCTION There are four basic types classified according to the point of insertion of PN code –D–Direct.

King Fahd University of Petroleum & Minerals Electrical Engineering Department EE 578 Simulation of Wireless Systems Code Division Multiple Access Transmission.

ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING(OFDM)

EE 445S Real-Time Digital Signal Processing Lab Fall 2013 Lab 4 Generation of PN sequences Debarati Kundu and Andrew Mark.

Course Summary Signal Propagation and Channel Models

1 Introduction to. 2 Contents: DEFINITION OF SPREAD SPECTRUM ( SS ) CHARACTERISTICS OF SPREAD SPECTRUM BASIC PRINCIPLES OF DIRECT SEQUENCE SPREAD SPECTRUM.

Lecture 8: Spread Spectrum

Direct Sequence Spread Spectrum vs

EE359 – Lecture 18 Outline Review of Last Lecture Multicarrier Modulation Overlapping Substreams OFDM FFT Implementation OFDM Design Issues.

EE359 – Lecture 19 Outline Review of Last Lecture OFDM FFT Implementation OFDM Design Issues Introduction to Spread Spectrum ISI and Interference Rejection.

Data and Computer Communications Eighth Edition by William Stallings Lecture slides by Lawrie Brown Chapter 9 – Spread Spectrum.

Course Summary Signal Propagation and Channel Models Modulation and Performance Metrics Impact of Channel on Performance Fundamental Capacity Limits Flat.

Lecture02 Spread Spectrum Communication By Engr. Muhammad Ashraf Bhutta.

From Stallings, modified and added1 Spread Spectrum Session 5 Nilesh Jha.

Chapter 13. Spread Spectrum Park Dong-Hyun Department of Information and Communications Engineering The Graduate School of Sejong University.

1 Chapter 7. Spread Spectrum Wen-Shyang Hwang KUAS EE.

Announcement Students that took EE392F last year: You need to drop EE392F this quarter and add EE392G instead, in order to get credit for this class.

1 William Stallings Data and Computer Communications 7 th Edition Chapter 9 Spread Spectrum.

Course Summary Signal Propagation and Channel Models Modulation and Performance Metrics Impact of Channel on Performance Fundamental Capacity Limits Flat.

Code Division Multiple Access (CDMA) Transmission Technology

1 Spread Spectrum Technology. 2 What is Spread Spectrum(SS) Spread Spectrum (SS) technology was first introduced by military as a way of sending secure.

Lecture 12-13: Multi-access Aliazam Abbasfar. Outline.

EE359 – Lecture 19 Outline Announcements Final Exam Announcements HW 8 (last HW) due Thursday 5pm (no late HWs) 10 bonus points for course evaluations.

Lecture 24-27: Ultra Wideband Communications Aliazam Abbasfar.

Stallings, Wireless Communications & Networks, Second Edition, © 2005 Pearson Education, Inc. All rights reserved Spread Spectrum Chapter.

EE359 – Lecture 18 Outline Announcements last HW posted, due Thurs 12/4 at 5pm (no late HWs) Last regular class lecture, Monday 12/1, 9:30-10:45 (as usual)

EE359 – Lecture 17 Outline Review of Last Lecture MIMO Decision-Feedback Receivers MIMO Sphere Decoders Other MIMO Design Issues Introduction to ISI Countermeasures.

TUNALIData Communication1 Spread Spectrum Chapter 9.

DATA AND COMPUTER COMMUNICATIONS Eighth Edition by William Stallings Lecture slides by Lawrie Brown Chapter 9 – Spread Spectrum.

EE359 – Lecture 19 Outline Announcements Final Exam Announcements HW 8 (last HW) due Sunday 5pm (no late HWs) Bonus lecture today 6-8pm (pizza/cake); Hewlett.

EE359 – Lecture 16 Outline ISI Countermeasures Multicarrier Modulation

William Stallings Data and Computer Communications 7th Edition

Chapter 5: Third generation systems-Wideband Digital Modulation

Chapter 6: Spread-Spectrum Communications

Outline Introduction Type of Multiplexing FDMA TDMA CDMA Future Work

Multiple Access Channels (MAC)

Digital transmission over a fading channel

DIRECT SEQUENCE SPREAD SPECTRUM WITH FREQUENCY HOPPING

Cellular and Wireless Networks Broadband Modulation-I

Spread Spectrum Chapter 7.

EE359 – Lecture 18 Outline Multiuser Systems Announcements

Chapter 5: Third generation systems-Wideband Digital Modulation

Spread Spectrum A signal that occupies a bandwidth of B, is spread out to occupy a bandwidth of Bss All signals are spread to occupy the same bandwidth.

EE359 – Lecture 18 Outline Announcements Review of Last Lecture

EE359 – Lecture 17 Outline Announcements Review of Last Lecture

Wireless Networks Fall 2007

EE359 – Lecture 7 Outline Announcements: Multipath Intensity Profile

Spread Spectrum Chapter 7.

William Stallings Data and Computer Communications 7th Edition

EE359 – Lecture 18 Outline Announcements Spread Spectrum

William Stallings Data and Computer Communications 7th Edition

EE359 – Lecture 19 Outline Multiple Access

Presentation transcript:

EE359 – Lecture 19 Outline Announcements Review of Last Lecture HW due 5pm today, New HW due next Thursday. Review of Last Lecture Spread Spectrum ISI and Inteference Rejection Code Autocorrelation Synchronization RAKE Receivers

Review of Last Lecture Multicarrier Modulation OFDM FFT Implementation of OFDM Frequency Selective Fading Mitigation Frequency Equalization Precoding (prescale by 1/a: channel inversion) Adaptive Loading Coding across Subcarriers

Spread Spectrum Modulation that increases signal BW Two types Mitigates or coherently combines ISI Mitigates narrowband interference/jamming Hides signal below noise (DSSS) or makes it hard to track (FH) Also used as a multiple access technique Two types Frequency Hopping: Narrowband signal hopped over wide bandwidth Direction Sequence: Modulated signal multiplied by faster chip sequence

Direct Sequence Spread Spectrum Bit sequence modulated by chip sequence Spreads bandwidth by large factor (K) Despread by multiplying by sc(t) again (sc(t)=1) Mitigates ISI and narrowband interference S(f) s(t) sc(t) Sc(f) S(f)*Sc(f) 1/Tb 1/Tc Tc Tb=KTc 2

ISI and Interference Rejection Narrowband Interference Rejection (1/K) Multipath Rejection (Autocorrelation r(t)) S(f) I(f) S(f)*Sc(f) Info. Signal Receiver Input Despread Signal I(f)*Sc(f) aS(f) S(f) S(f)*Sc(f)[ad(t)+b(t-t)] brS’(f) Info. Signal Receiver Input Despread Signal

Pseudorandom Sequences Autocorrelation determines ISI rejection Ideally equals delta function Maximal Linear Codes No DC component Large period (2n-1)Tc Linear autocorrelation Recorrelates every period Short code for acquisition, longer for transmission In SS receiver, autocorrelation taken over Tb Poor cross correlation (bad for MAC) 1 -1 2n-1 Tc -Tc

Synchronization Adjusts delay of sc(t-t) to hit peak value of autocorrelation. Typically synchronize to LOS component Complicated by noise, interference, and MP Synchronization offset of Dt leads to signal attenuation by r(Dt) 1 -1 2n-1 Tc -Tc r(Dt) Dt

Main Points Spread spectrum spreads signal over wide bandwidth for ISI/interference rejection DSSS rejects interference by spreading gain DSSS rejects MP by code autocorrelation Synchronization depends on autocorrelation properties of spreading code.

Happy Thanksgiving