report_project_2

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ELEG 6913

DIGITAL COMMUNICATION OVER FADING CHANNEL

Project 2 Report

STUDENT NAME:

PATEL, KIRTIKUMAR. MODI, BHUVAN

SUBMITTED TO:

Annamalai, Annamalai Jr., Ph.D

Associate Professor

Department of Electrical and Computer Engineering

Prairie View A&M University


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Topic: Throughput Optimization Using Adaptive Techniques

Objective: Maximization of single user throughput in a wireless channel

using the symbol rate, Packet length, and the constellation

size of MQAM modulation as optimization variables.

Introduction:Throughput is defined as the number of bits per second correctly received. It can

be affected by various by the channel environment such as the distance between

transmitter and receiver, the fading state of the channel, and the noise and the

interference power characteristics. After carefully reviewing [1] and [2] we came to know

that symbol rate, Packet length, and the constellation size are SNR dependent and can

be adapted dynamically in response to the mobility of a wireless data terminal.


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0 2 4 6 8 10 12 14 16 18 200

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

Received SNR(dB)

SpectralEfficiency(bps/Hz)

AWGN


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-10 -5 0 5 10 15 20 25 300

1

2

3

4

5

6

7

8

Received SNR(dB)


QPSK

BPSK

16 QAM

64 QAM


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-10 -5 0 5 10 15 20 25 300

0.5

1

1.5

2

2.5

3

Received SNR(dB)


L = 256

L = 64

L = 32


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-10 -5 0 5 10 15 20 25 300

0.5

1

1.5

2

2.5

3

Received SNR(dB)


R = 125KHz

R = 250 KHz

R = 500 KHz

R = 1 MHz

close all;

clear all;

Eb = -10:1:30;

SNR = 10.^(Eb/10);

b = 2;

Rs = 1000000;

L = 100;

C = 16;

W = 10^6;

Ls = L/b;

for m = 1:length(SNR)

x = sqrt((3*SNR)/(2^b-1));

y = 4*(1-2^(-b/2));

P = y*qfunc(x); % Equation (6)

f = (1-P).^Ls; % Equation (4)T = ((L-C)/L)*b*Rs*f; % Equation (1)

Z = (4*b*C)./log(1-P);

L1 = C/2 + 0.5.*(sqrt(C*C)-Z); % Equation (9)

T1=T/W; % Throughput in Bps/Hz

end

figure(1)

plot(Eb,T1,'r+-');

hold on;

xlabel('Received SNR(dB)'),ylabel('Spectral Efficiency(bps/Hz)')


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axis([-10 30 0 3]);

grid On;

%figure(2)

%plot(Es,z,'r+-');

%plot(Eb,L1,'r+-');

%xlabel('Received SNR(dB)'),ylabel('Spectral Efficiency(bps/Hz)')

%grid On;

%hold on;

%figure(3)

%plot(Es,z,'r+-');

%plot(Eb,Y,'r+-');

%xlabel('Received SNR(dB)'),ylabel('Spectral Efficiency(bps/Hz)')

grid on;

hold on;

References:

[1] T. Yoo, R. J. Lavery, A. Goldsmith and D. J. Goodman, ThroughputOptimization UsingAdaptive Techniques, submitted to ICC2004.[2] T. Yoo, R. J. Lavery, A. Goldsmith and D. J. Goodman, ThroughputOptimization UsingAdaptive Techniques, Draft submitted to IEEE Communications Letters,

2005.

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