A Study of the Communication Channels and of Noise Sources

8/11/2019 A Study of the Communication Channels and of Noise Sources

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The study of the communication channel and of noise sources

I1.The block scheme in the case of “uniform random demo“:

UniformMux

Mean

& var

Graph[.5 1/12]

Expected value

The first device is uniform noise generator which generates uniformly distributed noise

between the lower and the upper bounds. The following device has at its output therunning mean to 1

st out-port and running variance to 2

nd out-port. The third block has as

output a constant(0.51/12) . The mux combines all the three input signals into larger

vectors.The graphs for different values of the sampling time:

sample time=0.1s sample time=1s sample time=5s.

I2.The block scheme for “Gaussian random demo”:

Mux

Mean

& stdGaussian

[0 1]

Expected value

The 1st block generates a Gaussian distributed noise with given mean and given variance.The mean is 0 and the variance is 1. The 2

nd block has at its output the running mean to

1st out-port and running standard deviation to 2

nd out-port. The 3

rd block has as output a

constant [0 1] . The mux combines all the three input signals into larger vectors.The graphs for different values of the sampling time:



sample time=0.1s sample time=1s sample time=5s

I3.The block scheme for “uniform integer demo”:

Random int MuxMean

& std

Graph

The first device generates integers randomly distributed in the range [0,M-1], where m is

the M-ary number,(M=8). The 2nd

block has at its output the running mean to 1st out-

port and running standard deviation to 2nd

out-port. The mux combines the two inputsignals into larger vectors.

The graphs for different values of the sampling time:


I4.The block scheme for “Poisson random demo”:

Poisson int

Poisson int

generator

Mux

Mean

& var

Graph1

.1Expected value

The first device generates Poisson distributed random integers. The 2

nd block has at its

output the running mean to 1st out-port and running variant to 2

nd out-port. The 3

rd block

has as output a constant 0.1 . The mux combines all the three input signals into larger

vectors.





I5.The block scheme for “Rayleigh random demo”:

The mean of the Rayleigh noise is s*sqrt(pi/2).

The variance of the Rayleigh noise is s 2*(2-pi/2)

Assume the sigma value is s, then:

RayleighMux

Mean

& var

Graph[sqrt(pi/2), (2-pi /2)]

Expected value

The first device generates Rayleigh distributed noise. The output vector size of this blockis the same as the vector size of the seed (sigma=1). The 2

nd block has at its output the

running mean to 1st

out-port and running variant to 2nd

out-port. The 3rd

block has asoutput a constant [sqrt(pi/2),2-pi/2]. The mux combines all the three input signals intolarger vectors.



I6.The block scheme for “rician random demo”:



The m ean value o f the sqaure of the Rici an noise output is 2+2K

and the variance of the square of the Rician noise output is 2(2+4K)

Assume the the sigma value i s 1, the means for in-phase and

quadrature are mI and mQ. T he K-factor K=(mI^2+mQ^2)/2, then,

Rician (m)

Rician (K)

Mux

Mean

& var

Mean

& var Graph

[6 20]

Expected value

The first block generates Rician distributed noise. The output vector size of this block is

the same as the vector size of the seed (K=2, sigma=1). The block from bellow is similar

having m=sqrt(2), sigma=1.The following blocks are multipliers or dividers. The other blocks have at its output the running mean to 1

st out-port and running variant to 2

nd out-

port. The block ‘expected value’ has as output a constant [6 20]. The multiplexer

combines all five input signals into larger signals.The graphs for different values of the sampling time:


II.1 The block scheme of the “AWGN noise demo”

Rd wksp - read from workspace- read from a work space variable at sampling time point.

S-QASK – passband S-QASK modulation – modulate the input signal using qadrature

amplitude shift keyng modulation method with square constellation.



AWGN channel, fixed parameter – additive with Gaussian nise channel with fixed

meanand variance.

S-QASK - passband S-QASK demodulation – demodulate a QASK modulated signal

using sqare constellation.Error meter – symbol/bit error counter – use the input data from the first port as the

reference signal to detect the no. of errors and error rate of the second port input signal.

Sigma=0.1

Stop

time

4 6 8 10 12 14 16 18 20

BER

symbol

0.25 0.15 0.21 0.13 0.14 0.12 0.15 0.133 0.125

BER bit 0.083 0.05 0.07 0.043 0.047 0.042 0.05 0.044 0.041

0

0.05

0.1

0.15

0.2

0.25

0.3

1 2 3 4 5 6 7 8 9

Series2

0

0.02

0.04

0.06

0.08

0.1

1 2 3 4 5 6 7 8 9

Series2

BER symbol=f(t) BER bit=f(t)

Sigma=1

Stop

time

4 6 8 10 12 14 16 18 20

BER

symbol

0.675 0.65 0.612 0.58 0.6 0.557 0.55 0.516 0.575

BER bit 0.275 0.3 0.270 0.26 0.261 0.219 0.22 0.212 0.253

0

0.2

0.4

0.6

0.8

1 2 3 4 5 6 7 8 9

Series2

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

1 2 3 4 5 6 7 8 9

Series2




II.2.The block scheme of the “Raylegh noise demo”:


S-QASK – passband S-QASK modulation – output the complex envelope of the QASK

modulated signal.This blok uses a sqare constellation with M-ary no. M=2^K,

where K is an integer.Rayl N – Rayleigh noise channel, fixed parameter – additive Rayleigh noise channel for

Baseband signal simulation. Input and output signals are complex.S-QASK – baseband S-QASK demodulation – demodulate the complex envelope of a

QASK modulated signal.This blok uses a fixed sqare constellation with M-ary no.M=2^K, where K is an integer.

Error meter – symbol/bit error counter – use the input data from the first port as the


Sigma=0.3

Stop

time

4 6 8 10 12 14 16 18 20

BER

symbol

0.05 0.066 0.025 0.04 0.05 0.057 0.037 0.044 0.03

BER bit 0.016 0.022 0.0083 0.013 0.016 0.019 0.0125 0.014 0.01



0

0.02

0.04

0.06

0.08

1 2 3 4 5 6 7 8 9

Series2

0

0.005

0.01

0.015

0.02

0.025

1 2 3 4 5 6 7 8 9

Series2


Sigma=3

Stop

time

4 6 8 10 12 14 16 18 20

BER

symbol

0.8 0.766 0.775 0.72 0.716 0.7 0.7 0.677 0.78

BER bit 0.433 0.388 0.408 0.366 0.355 0.323 0.333 0.359 0.403

0.6

0.65

0.7

0.75

0.8

0.85

1 2 3 4 5 6 7 8 9

Series2

0

0.1

0.2

0.3

0.4

0.5

1 2 3 4 5 6 7 8 9

Series2


II.3 The block scheme of the “Rician noise demo”:


C-QASK – baseband C-QASK modulation – output the complex envelope of a QASKmodulated signal. The QASK circle constellation is defined by the NIC,RIC

and PIC.

Rician N – Rician noise channel, fixed parameter – additive Rician noise channel for a baseband sinal simulation. Input and output sgnals are complex.



C-QASK – baseband C-QASK demodulation – demodulate the complex envelope of a

QASK Circle constellation is defined by NIC,RIC and PIC.

Error meter – symbol/bit error counter – use the input data from the first port as the


Sigma=0.1

Stop

time

4 6 8 10 12 14 16 18 20

BER

symbol

0.3 0.2 0.1 0.18 0.15 0.128 0.087 0.088 0.12

BER bit 0.071 0.052 0.028 0.054 0.047 0.036 0.032 0.025 0.035

0

0.1

0.2

0.3

0.4

1 2 3 4 5 6 7 8 9

Series2

0

0.02

0.04

0.06

0.08

1 2 3 4 5 6 7 8 9

Series2


Sigma=1Stop

time

4 6 8 10 12 14 16 18 20

BER

symbol

0.75 0.666 0.625 0.6 0.633 0.642 0.625 0.622 0.64

BER bit 0.22 0.209 0.16 0.165 0.19 0.187 0.189 0.182 0.174



0

0.2

0.4

0.6

0.8

1 2 3 4 5 6 7 8 9

Series2

0

0.05

0.1

0.15

0.2

0.25

1 2 3 4 5 6 7 8 9

Series2


Laboratory 2

Multiple access techniques

III .1 D-TMA demo

Signal generator – output various wave forms-sine, sawtooth, sine.Mux – combine scalar or vector signals into larger vectors.

D-TDMA mux – digital TDMA input a vecor digital signal. Output a scalar up-sampled

digital signal.D-TDMA demux – reverse digital signal. Output a vector of a down-sampled digital

signal.

Demux – split vector signal into scalars or smaller vectors.

Stop time=10

Input sample time for D-TMAmux and D-TMA dmux=0.01



Input sample time for D-TMAmux and D-TMA dmux=0.1

Input sample time for D-TMAmux and D-TMA dmux=1

III.2 Time share demo



Signal generator – output various wave forms-sine, sawtooth, sine.

Mux – combine scalar or vector signals into larger vectors.

Time share mux – analog time division multi access – this block partititions each transfer period into even length time slots.Each element of the input vector takes one slot in turn.

Time share demux – reverse analog TDMA – This block partitions each transfer peiodinto even length time slots.Each element of the output vector takes one time slot to outputthe input in turn.


Stop time=10

Transfer period at “time share-mux” and “time-share demux”=0.001sec



Transfer period at “time share-mux” and “time-share demux”=1sec



III.3 FDMA demo


DSB AM – passband DSB_SC AM – modulate the input signal using DSB-SC AMmethod.

Butter(BP) – butterworth band pass filter.

Sum – add or substract inputs.

AWGN channel, fixed parameter – additive with Gaussian nise channel with fixedmeanand variance.

DSB ADM – passband DSB-SC AM modulated signal.Mux – combine scalar or vector signals into larger vectors.

Stop time=10

Filters’ bandwidth=0.03

Variance of the noise in the channel=0.01

Stop time=10

Filters’ bandwidth=0.03 Variance of the noise in the channel=0.1



Stop time=10


Variance of the noise in the channel=1

Stop time=10Filters’ bandwidth=0.003


Stop time=10





Stop time=10



Stop time=10Filters’ bandwidth=0.3


Stop time=10





Stop time=10



III.4 CDMA demo


Mux – combine scalar or vector signals into larger vectors.Pulse generator – vector pulses with sample rate of each pulse as Sample_time/Divider.

Vector signal re-distribution – the rising edge from the 2nd

inport triggers the block to

output the input element with the index given in the next row of switch box.



AWGN channel, fixed parameter – additive with Gaussian nise channel with fixed

meanand variance.


DSB-AM – passband DSB-SC AM – modulate the input signal using DSB-SC AM

method.

Sum – add or substract inputs.Butter(BP) – butterworth band pass filter.

Butter(BP) – butterworth band pass filter.

DSB ADM – passband DSB-SC ADM – demodulate a DSB-SC AM modulated signal.Mux – combine scalar or vector signals into larger vectors.

Unit delay – sample and hold with one sample period delay.Edge detection – detect the rising edge of the input signal.Output one when the risig edge

is detected.

Sum – add or substract inputs.Zero order hold.



Stop time=10



Stop time=10Filters’ bandwidth=0.03 Variance of the noise in the channel=0.1

Stop time=10

Filters’ bandwidth=0.03 Variance of the noise in the channel=1



Stop time=10



Stop time=10



Stop time=10

Filters’ bandwidth=0.3 Variance of the noise in the channel=1

A Study of the Communication Channels and of Noise Sources

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