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IMPLEMENTATION OFLONG TERM EVOLUTION

PHYSICAL LAYER

Guided by:

Dr. T. Arivoli

Visiting Faculty

KLU

P.C.Vijay Ganesh

9910114015


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ABSTRACT Mobile broadband is becoming a reality.

Long-Term Evolution (LTE) and WiMax with data rate of 100Mbps

Round-trip time is less than 10ms

LTE supports flexible carrier bandwidths.

LTE supports both FDD (Frequency Division Duplex) and TDD

(Time Division Duplex)

To implement LTE Downlink With 2x2 MIMO


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INTRODUCTION

Generation Throughput Technology When was itaround

1G 14.4 Kbps AMPS,NMT,TACS 1970 - 1980

2G 9.6/14.4 Kbps TDMA,CDMA 1990 - 2000

2.5G 171.2 Kbps,

20-40 Kbps

GPRS 2001 - 2004

3G 3.1 Mbps ,

500-700 Kbps

CDMA 2000

(1xRTT, EVDO)

UMTS, EDGE

2004 - 2005

3.5G 14.4 Mbps1-3 Mbps HSPA 2006 - 2010

4G 100-300 Mbps, 3-5

Mbps

WiMax, LTE,

Wi-Fi

Now


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OBJECTIVE Design and implement a subset of the Physical Layer of LTE as perthe specification of 3rd Generation Partnership Project.

Designing a digital baseband transceiver.

DownLink

2x2 MIMO

Broadcast


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IMPLEMENTATION METHOD

Designing and verification of modules in LTE Downlink

Integration of modules

Simulink , Xilinx System Generator for simulation


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DL LTE Transmitter

CRC

Coding

Rate matching

Scrambler

Modulation

Resource mappingIFFT

Cyclic PrefixReference Signals


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DL LTE Receiver

CRC

Viterbi de-coding

De - Rate matching

ScramblerDe-Modulation

Resource de mapping

FFT

Remove Cyclic Prefix

Channel Estimator

Equalizer


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MODULE SPLIT UP

CRC

Modulation

Scrambler

Coding

Rate Matching

Resource Mapping

OFDMA Generator


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CYCLIC REDUNDANCY CHECK

16 bit and 24 bit CRC

16 bit polynomial

X16+X12+X5+1

Used PBCH, PDCCH,SSS

24 bit polynomial

X24+X23+X6+X5+1

Used for CRC in PDSCH


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CODING

Convolution Coding 1/3 rate

D D D D D D

Din

D0k

D1k

D2k


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RATE MATCHING

Interleaving three bit from Convolution Coding D0k, D1k,D2k

Collection of Bits

Generate Circular Buffer

Sub Block

Interleaver

Sub Block

Interleaver

Sub Block

Interleaver

Bit

Collection

Circular

Buffer

D0k

D1k

D2k

V0k

V1k

V2k

Wk Ek


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SCRAMBLER

Pseudo-random sequence of length 31

C(n) = (X1(n) + X2(n)) mod 2

X1(n) = (X1(n+3) + X1(n)) mod 2

X2(n) = (X2(n+3)+X2(n+2)+X2(n+1)+X2(n))mod 2

Initial condition

X1(0) = 1

Else X1(n) = 0

Cinit = X2(i).2ii=0.30

X2(n) depends on cell identity


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SCRAMBLERX1(n)

X2(n)

Din Dout

C(n)


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MODULATION

QPSK

16 QAM

64 QAM


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Layer Mapping

Equal to Antenna Port

Separate into odd and even symbols

Y0(n) = M(2i) and Y1(n) = M(2i+1); i = 0.n

Layer

Mapping

Pre

Coding

M(n)

Y0(i)

Y1(i)


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Pre coding

Code book for pre coding

Code book for antenna port {0,1}

Index Layer 1 Layer2

1 1/2[1 -1]T 1/2 [1 11 1

]

2 1/2[1 -j]T1/2 [

1 1

]


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Reference Signals

Cell Specific Reference Signals

Transmitted in all Downlink sub frame.

One or several antenna port (0 to 3)

P1 P0

P0 P1

P1 P0

P0 P1

0 6


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Synchronization Signal

Primary synchronization signal

Zadeoff-chu sequence

D(n) = e(-j(( + 1)/63))n= 0,1.30

D(n) = e(-j(( + 1)( + 2)/63))n = 31,32. 61

U = 25

occupies symbol 6 of slot #0 and slot #10

Secondary Synchronization signal

Contains System information Block

Occupies symbol 5 of slot #0 and slot #10


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RESOURCE MAPPING

1 0 1 0

0 1 0 1

1 0 1 0

0 1 0 1

Primary Sync. Signal

Secondary Sync. Signal

PBCH Signal

Reference

Signal

DTX

0 13


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OFDMA Generation

OFDMIFFT

Cyclic

Insertion

Tu Tcp + Tu

Tcp

Rn


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LTE FDD Frame Structure


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LTE FDD Frame Structure

In LTE the timing definitions are defined in multiples of base time

unit Ts = 1/(15k * FFT(N))

Ts = 32.552 ns for FFT size of 2048

The time intervals can thus also be expressed as

Tframe = 307 200 * Ts, For frame ( 10 ms)

Tsubframe = 30 720 * Ts, for subframe (1 ms)

and Tslot = 15 360 * Ts for slot (0.5 ms)


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Receiver


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Implementation of CRC


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Result


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TOOLS

Matlab Simulink

Designing the model for Downlink of LTE

Xilinx ISE Synthesis model/ HDL code

Modelsim

Simulating model/HDL code


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ACTION PLANMONTH WEEK WORK PLANNED

July 1st & 2nd Discussion of area and title

July 3rd & 4th Study of Specification

August 1st & 2nd Downlink module Analysis

August 3rd & 4th Designing of CRC & Channel Coding

September 1st & 2nd Design of Rate matching and Segmentation

September 3rd & 4th Design of Scrambler and modulation

October 1st & 2nd Design of Layer and antenna mapping

October 3rd & 4th Integration of above Blocks and functional

testing


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LITERATURE SURVEY

L. Chen, W. Chen, B. Wang, X. Zhang, H. Chen, and D. Yang, System-

Level Simulation Methodology and Platform for Mobile Cellular

Systems,IEEE Communications Magazine, 2011, pp. 148-155.

Unified modeling of WiMax and LTE.

Object driven method and verify with standards

G. Piro, L.A. Grieco, G. Boggia, F. Capozzi, and P. Camarda, Simulating

LTE Cellular Systems : An Open-Source Framework,IEEE Transactions

on VEHICULAR Technology, vol. 60, 2011, pp. 498-513.

Complete performance verification of LTE networks.


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LITERATURE SURVEY

J.C. Ikuno, M. Wrulich, and M. Rupp, System level simulation of

LTE networks, Vehicular Technology Conference, 2010, pp. 1-5.

performance of the Downlink Shared Channel of LTE SISO and MIMO

using Matlab.


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LITERATURE SURVEY[1] 3GPP, TS 36.211 Physical Channel and Modulation, V10.1.0

(Release 10),2011.

[2] 3GPP, TS 36.212 Multiplexing and Channel coding , V 10.1.0

(Release 10), 2011.

[3] J.S. Erik Dahlman, Stefan Parkvall, 4G LTE/LTE-Advanced for

MobileBroadband, Academic Press, 2011.

[4] Farooq Khan, LTE for 4G Mobile Broadband, NewYork, USA: Cambridge University Press, 2009.


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LITERATURE SURVEY

[5] Erik Dahlman, Stefan Parkvall, Johan and Per Beming, 3G

EVOLUTION : HSPA AND LTE FOR MOBILE

BROADBAND, second edition, Acadamic Press, 2008.

[6] Long Term Evolution Protocol Overview, freescale white paper,

2007.

[7] Daniel Garsia-Alis, Lian Strling and Bob Stewart, Introduction to

LTE , Steepest Assent Ltd, 2009.[8] LTE standard, Overview of 3GPP Release 8 V0.1.0, 2010;


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Thank You

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