Incremental Pilots in OFDM Parichaya Shrivastava.

Slides:

Advertisements

Similar presentations

OFDM Transmission Technique Orthogonal Frequency Division Multiplexer

Advertisements

Multi-carrier CDMA. Outline Introduction System Model Types Applications References.

Communication System Overview

1 PIANO+ OTONES WP3 SIGNAL PROCESSING ALGORITHMS.

VSMC MIMO: A Spectral Efficient Scheme for Cooperative Relay in Cognitive Radio Networks 1.

Anatomy of Radio LAN Onno W. Purbo

IEEE802.16d IEEE802.16d Simulator WirelessMAN-OFDM-PHY layer Mohamad Charafeddine Rev-s3 24 Sept 2004.

Resource Allocation Software Algorithms for AMC-OFDM Systems Dr. Muayad Sadik Croock Computer Engineering Department, University of Technology 1.

Division multiplexing

a By Yasir Ateeq. Table of Contents INTRODUCTION TASKS OF TRANSMITTER PACKET FORMAT PREAMBLE SCRAMBLER CONVOLUTIONAL ENCODER PUNCTURER INTERLEAVER.

Channel Estimation in OFDM Systems Zhibin Wu Yan Liu Xiangpeng Jing.

OFDM based for WIFI Ziqi SONG Zhuo ZHANG Supervisor: Prabin.

EE302 Lesson 21: Transmission of Binary Data in Communication Systems

1 Peak-to-Average Power Ratio (PAPR) One of the main problems in OFDM system is large PAPR /PAR(increased complexity of the ADC and DAC, and reduced efficiency.

Channel Estimation for Mobile OFDM

Semi-Blind Equalization for OFDM using Space-Time Block Coding and Channel Shortening Alvin Leung Yang You EE381K-12 March 04, 2008.

Department of electrical and computer engineering An Equalization Technique for High Rate OFDM Systems Mehdi Basiri.

IERG 4100 Wireless Communications

1 EQ2430 Project Course in Signal Processing and Digital Communications - Spring 2011 On phase noise and it effect in OFDM communication system School.

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

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

Wireless communication channel

Muhammad Imadur Rahman1, Klaus Witrisal2,

Design of Expanded Constellations for PAPR Reduction in OFDM Systems Speaker: Dr. Ali Al-Shaikhi Assistant Professor, EE department.

TAP Channel Measurement Fundamentals, Goals, and Plans.

Usage of OFDM in a wideband fading channel OFDM signal structure Subcarrier modulation and coding Signals in frequency and time domain Inter-carrier interference.

ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING(OFDM)

Orthogonal Frequency Division Multiple Access (OFDMA)

National Institute Of Science & Technology OFDM Deepak Ranjan Panda (EI ) [1] Orthogonal Frequency Division multiplexing (OFDM) Technical Seminar.

OFDM Presented by Md. Imdadul Islam.

Wireless Mobile Communication and Transmission Lab. Chapter 8 Application of Error Control Coding.

Inter-carrier interference cancellation in OFDM systems By: Dharamveer Meena Vinodkumar Pralia.

林宏穎: OFDM Introduction

OFDM Each sub-carrier is modulated at a very low symbol rate, making the symbols much longer than the channel impulse response. Discrete Fourier transform.

Multiuser OFDM with Adaptive Subcarrier, Bit and Power Allocation (IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, VOL. 17, NO. 10, OCTOBER 1999)

Adaptive Resource Allocation for OFDMA Systems Mr. Zukang Shen Mr. Ian Wong Prof. Brian Evans Prof. Jeff Andrews April 28, 2005.

1 WP2.3 “Radio Interface and Baseband Signal Processing” Content of D15 and Outline of D18 CAPANINA Neuchatel Meeting October 28th, 2005 – Marina Mondin.

Presented by: Ahmad Salim. 2  The acronym WiMAX stands for “Worldwide Interoperability for Microwave Access”. It is based on IEEE standard for.

Implementation of OFDM Transmitter based on the IEEE d Standard Presented by: Altamash Janjua Group Partner: Umar Chohan Supervisors: Dr. Brian L.

Wireless Multiple Access Schemes in a Class of Frequency Selective Channels with Uncertain Channel State Information Christopher Steger February 2, 2004.

Orthogonal Frequency Division Multiplexing

Modeling a Multicarrier Wireless Communication Transceiver Embedded Software Systems Literature Survey March 24,2004 By Hunaid Lotia.

Presented by: Ahmad Salim. 2  The acronym WiMAX stands for “Worldwide Interoperability for Microwave Access”. It is based on IEEE standard for.

PAPR Reduction Method for OFDM Systems without Side Information

FMT Modulation for Wireless Communication

Amplifier Nonlinearities in OFDM Multiple Antenna Systems FERNANDO GREGORIO Signal Processing Laboratory HUT.

Dr. Ahmed El-MahdySpread Spectrum Communications (1) Performance of LTE uplink over frequency selective fading channel in impulsive noise environment (2)

Single carrier  Multicarrier  OFDM Single Carrier - ISI, Receiver complexity  ISI, Bit rate limitation Multi-carrier - Negligible ISI, Approximately.

S , Postgraduate Course in Radio Communications

Introduction to OFDM and Cyclic prefix

<month year> <doc.: IEEE doc> March 2013

Advanced Wireless Networks

Evaluation of coded OFDM systems using different type of codes

Orthogonal Frequency Division Multiplexing ...

Linglong Dai and Zhaocheng Wang Tsinghua University, Beijing, China

Tsinghua University, Beijing, China

Klaus Witrisal Signal Processing and Speech Communication Lab

Channel Estimation 黃偉傑.

Synchronization Algorithms for OFDM Systems

ELEG 6203: "Wireles Networks" Wireless Networks December 04,2003

Systems with Reduced Complexity

Ian C. Wong, Zukang Shen, Jeffrey G. Andrews, and Brian L. Evans

Channel Estimation in OFDM Systems

Supplementary Channel for Talk-around Direct Communications

EE359 – Lecture 17 Outline Announcements Review of Last Lecture

Wireless OFDM Systems Prof. Robert W. Heath Jr.

Linglong Dai and Zhaocheng Wang Tsinghua University, Beijing, China

Channel Estimation in OFDM Systems

OUT OF BAND AND ICI REDUCTION TECHNIQUE

Presentation transcript:

Incremental Pilots in OFDM Parichaya Shrivastava

What will we discuss? Brief overview of OFDM – Why use OFDM? – How does it work? Pilots – Why do we need them? Incremental Pilots -Concept -What am I trying to do?

Higher spectral efficiency Lower multi-path distortion Why use OFDM?

Higher spectral efficiency

Example of an OFDM modem

Multipath problem

A Multipath solution

The Multipath solution

Example of an OFDM modem

OFDM challanges Synchronization requirements are much more strict : – Requires more complex algorithms for time / frequency synch Peak-to-average power ratio – Large signal peaks require higher power amplifiers – Amplifier cost grows nonlinearly with required power

Pilot based OFDM system model

Main equation: Channel estimation equation

Frequency domain channel estimation

Pilot allocation 1

Pilot allocation 2

Why Incremental Pilots? Some channels (e.g. where there is more frequency selective fading), increased number of pilots will help. More pilots -Interpolation error small -> Better channel estimation -> Better BER

Channel encoder Data sub- carriers Pilot subcarrie rs IFFT CP S/ P 16- QA M Pilot PN Sequence BPSK P/ S DAC Transmitter with channel encoder

Incremental pilots trade-off Better CE Better BER Less redundancy: Worse BER Less redundancy: Worse BER Loss in redundancy acceptable

Loss in redundancy. Crude figure

Work to do See the performance under different channel conditions Different coding schemes (Convolutional, Turbo, LDPC) Complexity of implementing higher coding rates for different coding schemes

References: 1.Eric Phillip Lawrey, Adaptive Techniques for multiuser OFDM Phd Thesis. Online Marina Mondi, Orthogonal Frequency Division Multiplexing/Modulation : OFDM. Online. 3.Keithley Corporation, An Introduction to Orthogonal Frequency Division Multiplex Technology. Online df df 4.Muhammad Saad Akram, Pilot-based Channel Estimation in OFDM Systems. Online Sung-Yoon Jung and Sunghwan Kim, Channel Estimation and LDPC Code Puncturing Schemes Based on Incremental Pilots for OFDM. ETRI Journal, Volume 32, Number 4, August 2010

Thank you!