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7/28/2019 Cdma Technology Seminar Ppt Way2project In
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1
An Introduction
To
CDMA Technology
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2
n
Short for Code Division Multiple Access
Developed by US company -QUALACOMM
uses spread-spectrum techniques
Digital technology for delivering mobile
telephone services
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3
Spread Spectrum Transmission Model
Information Signal
i(t)
Data Rate RiBandwidth Wi
Spreading Sequence
Chip Rate Rc
Bandwith Wc
c(t)
Spreading Sequence
Chip Rate Rc
Bandwidth Wc
c(t)
s(t) r(t) d(t)
jammer interference
Filter
Bandwidth WRecovered
Informational
Signal
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4
Classification of Spread Spectrum Systems
Spread Spectrum Techniques
Direct SequenceTime Hopper Frequency Hopper Hybrid
Wideband Narrowband
Slow Fast
DS/FH
DS/TH FH/TH
DS/FH/TH
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5
Power Control Mechanism
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7
IS-95 CDMA
ed on IS-95 Technology
Supports 95 million subscribers worldwide
Network operate in 800 & 1900 freq. band
Provides voice & data services having speedupto 64 kbits/sec
SMS services also
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8
000/IS 2000
CDMA-2000
CDMA-2000 1X CDMA-2000 3X
I Phase II Phase
144kbps packet data rate
Two fold increase in both voice capacity &
standby time
Advanced packet data services
Greatly extended battery life
Channel size of 1.25 MHz
Circuit & packet data rates up to
2Mbps
Incorporates advanced multimedia
capabilities
Supports framework for advanced 3G
voice services & vocoders
Channel sizes- 5MHz,10MHz
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9
Benefits of CDMA
Increased Capacity
Improved Quality
Simplified System PlanningEnhanced Privacy
Improved Coverage
Increased Portable Talk Time
Bandwidth on Demand
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10
CDMA-Applications
CDMA for Cellular
CDMA-Short Message Service
Over-the-Air Activation CDMA Data and Fax
Subscriber Access Control
CDMA for Personal Communications Services
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Conclusion
Technology of choice for 3G generation because of it’s
Greater total capacity
Outstanding voice quality
Fewer dropped calls
RF planning and implementation is simplified by it’s
Capability of re-using single cell frequency
non-contiguous bandwidth requirement
It’s use in satellite communication is of great importance
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CDMA for Cellular
CDMA-Short Message Service
Over-the-Air Activation CDMA Data and Fax
Subscriber Access Control
CDMA for Personal Communications Services
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14
000/IS 2000
CDMA-2000
CDMA-2000 1X CDMA-2000 3X
I Phase II Phase
144kbps packet data rate
Two fold increase in both voice capacity &
standby time
Advanced packet data services
Greatly extended battery life
Channel size of 1.25 MHz
Circuit & packet data rates up to
2Mbps
Incorporates advanced multimedia
capabilities
Supports framework for advanced 3G
voice services & vocoders
Channel sizes- 5MHz,10MHz
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15
Benefits of CDMA
Increased Capacity
Improved Quality
Simplified System PlanningEnhanced Privacy
Improved Coverage
Increased Portable Talk Time
Bandwidth on Demand
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16
Benefits of CDMA
Increased Capacity
Improved Quality
Simplified System PlanningEnhanced Privacy
Improved Coverage
Increased Portable Talk Time
Bandwidth on Demand
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17
Benefits of CDMA
Increased Capacity
Improved Quality
Simplified System PlanningEnhanced Privacy
Improved Coverage
Increased Portable Talk Time
Bandwidth on Demand