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RF-LAN FOR SATELLITEBy
Hemanth kumar.S
Under the guidance of
Dr. Sambasiva Rao
1
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Agenda
Item 5
Literature survey
Implementation
Introduction
Advantages
Reference
Item 1
Item 3
Item 2
Item 4
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INTRODUCTION
Propulsionsystem
Acceleros
gyros
Reaction
wheels
Star sensor
Batteries
Earth sensor
Thermal control
Solargenerator
Power
distribution
paylod
DT system
Navigation
camera
GPS
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[1] Arbab Waheed Ahmad, Guochen Fan, Guodong Xu, "Implementation of
ZigBee-GSM based Home Security Monitoring and Remote Control
system" IEEE Transactions on Consumer Electronics, Vol.56 No. 4,
pp: 2241-2248,2010.
[2] Ali N. Akansu, "Walsh-Like Nonlinear Phase Orthogonal Codes for Direct
Sequence CDMA Communications" , IEEE transactions on signal
processing, VOL. 55, NO. 7, JULY 2007.
[3] Shaobin Li, Guochen Fan, Guodong Xu, "Application of Wireless Satellite
Bus in micro-satellite design" ,International Conference on Mechatronics
and Automation August 9 - 12, Changchun, China, 2009.
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CDMA TECHNIQUE
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Anti jamming capability
Interference rejection
Secure communication
Multipath protection
Bandwidth ofthe
transmittedsignal is much
greater thanthat of the
message thatmodulates the
carrier
Thetransmissionbandwidth is
determined by
a factorindependent
of themessage
bandwidth
DSSS
FHSS
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Multiplication with the code sequencewhich is of a higher bit rate.
The ratio of the code rate to theinformation bit rate is called both thespreading factor
To distinguish the information bit ratefrom the code rate, we call the code
rate, chipping rate.
SPREADING CODES
CRITERION
Balancedsequence
OrthogonalEqual runsof 0s and
1s
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Walsh code generator PRBS
Several spreading codes are popular for use in practical spread spectrum system
M-sequence code
Gold codes
Kasami codes &
barker codes
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Walsh codes are created out of Haddamard matrices andTransform.
In a family of Walsh codes, all codes are orthogonal to eacother and are used to create channelization
The seed matrix is,
to derive a set of four orthogonal Walsh sequences w0, w1, w2, and
w3, we only need to generate a Hadamard matrix of order 4, or22
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LFSR
Longer length code
1 1 1 1 0
0 1 1 1 00 0 1 1 0
0 0 0 1 1
1 0 0 0 0
0 1 0 0 0
0 0 1 0 1
1 0 0 1 1
1 1 0 0 0
0 1 1 0 1
1 0 1 1 0
0 1 0 1 1
1 0 1 0 1
1 1 0 1 1
1 1 1 0 1
1 1 1 1 0
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BASIC BLOCK DIAGRAM OF CDMA
In CDMA, each usersnarrowband signal is spread over
a wider bandwidth.
Each users narrowband signal isspread by a different widebandcode
Basic Block Diagram to Illustrate CDMA technique
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Approach-1
More BER
Simpler
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Approach-2
Less BER
Immune to
Channel noise
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BASIC OPERATIONS IN CDMA11/28/2012 14/20
S(t)= 2d(t)g(t)
S(t)= 2d(t)g(t)sin(2)
rcv(t)= 2d(t)g(t)sin 2
rcv(t)= 2d(t)g(t)(1-cos 4 )
rcv(t)= 2d(t)g(t)
rcv(t)= d(t)g(t)g(t)
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ILLUSTRATION TRANSMITTER
user
1
user
2
user
3
user
4
0
1
0
1
-1
+1
-1
+1
1 1 1 1
1 -1 1 -1
1 1 -1 -1
1 -1 -1 1
-1 -1 -1 -1
1 -1 1 -1
-1 -1 1 1
1 -1 -1 1
0 -4 0 0
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ILLUSTRATION RECIEVER
1 1 1 1
1 -1 1 -1
1 1 -1 -1
1 -1 -1 1
0 -4 0 0
0 4 0 0
0 -4 0 0
0 4 0 0
0 -4 0 0
-4 -1 0
4 +1 1
-4 -1 0
4 +1 1
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FDMA
Bandwidth is
divided intoseparate frequency
bands
Bandwidth limited
TDMABandwidth is time
shared
Bandwidth limited
CDMASimultaneous
datatransmissionusing coding
theory
Soft capacityInterference
limitedCombat
multipath fading
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2012-2013
Phase-1
Phase-2
Performance analysis
Implementation
Testing
AugJunMayAprMarFebDecNovoctSep Jan Jul
Literarure survey
Problem defination
Simulation of CDMA
Studying of ACF
Desiging PLL
Phase-3
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CDMA RF System Engineering by Samuel C.
Yang
CDMA Mobile Radio Design by John B. Groe
Lawrence E. Larson.
www.complextoreal.com
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THANK YOU
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