CDMA and 3G technologies allow for improved wireless communication capabilities like streaming videos on phones and increased data speeds. CDMA uses spread spectrum technology, which transmits power across a wide frequency band, making the signal difficult to intercept. It provides benefits like higher capacity, improved performance in multipath environments, and lower power consumption. 3G supports flexible delivery of voice, messaging, multimedia and high-speed data services for mobile users across global networks.

1. CDMA & 3G

2. Introduction
• Technologists continued to develop ever
newer technologies
• Operators and service providers come up with
innovative applications and services
• Users expect quality voice and data services
while on the move
• CDMA & 3G create the possibility for playing
videos on the phone and interface the phone
to the network

3. Introduction
• Spread spectrum technology as an option for
wireless communication
• FDMA TDMA  CDMA
• 3G was in gestation in 1992
• ITU-2000 (Year 2000, 2000MHz or 2Ghz,
2000kbps or 2Mps)
•

4. Introduction
• Spread spectrum is transmission of power over a
complete band
• Techniques
– Direct Sequence (digital information with pseudo
random code)
– Frequency Hoping (changing frequency many times
within a fixed time period in accordance with a
pseudo-random list of channels
– Time
– Chirp (radar systems)
– Hybrid system (combining two or more)

5. Introduction
• CDMA is a military technology first used during World War
II by English allies to foil German attempts at jamming
transmissions. The allies decided to transmit over several
frequencies, instead of one, making it difficult for the
Germans to pick up the complete signal.
• Because Qualcomm created communications chips for
CDMA technology, it was privy to the classified
information. Once the information became public,
Qualcomm claimed patents on the technology and became
the first to commercialize it.

6. Why CDMA?
• Higher capacity
• Improved performance in multipath by diversity
• Lower mobile transmit power = longer battery life
– Power control
– Variable transmission rate with voice activity detection
• Allows soft handoff
• Sectorization gain
• High peak data rates can be accommodated
• Combats other-user interference = lower reuse
factors

7. 3G
• Flexible support of multiple services
– Voice
– Messaging – email, fax, etc.
– Medium-rate multimedia – Internet access, educational
– High-rate multimedia – file transfer, video
– High-rate interactive multimedia – video telecon-ferencing,
telemedicine, etc.
• Mobility: quasi-stationary to high-speed platforms
• Global roaming: ubiquitous, seamless coverage
• Evolution from second generation systems

8. • Mobile Technologies include technologies like

9. The IS-95 Architecture Model

10. • Handoff management
• Break before make vs make before break