CDMA Technology Full Download Seminar Report and Paper Presentation

[seminar class]

Prepared By
Shashank arora,

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Type of Multiplexing:
Frequency-Division Multiple Access (FDMA)
Time-Division Multiple Access (TDMA).
Code-division Multiple-Access (CDMA)
Frequency-Division Multiple Access (FDMA)
It is a communications technique that divides a communications channel into a number of equally spaced frequency bands
Time-Division Multiple Access (TDMA)
It is a digital transmission technology that allows a number of users to access a single radio-frequency (RF) channel without interference by allocating unique time slots to each user within each channel.
Code Division Multiple Access (CDMA)
is a wireless communications technology that uses the principle of spread spectrum communication.
There are three ways to spread the bandwidth of the signal:
 Frequency hopping
 Time hopping
 Direct sequence
 CDMA is a Direct Sequence Spread Spectrum system
 CDMA Features:
o All users use same frequency and may transmit simultaneously
o Narrowband message signal multiplied by wideband spreading signal, or codeword
o Each user has its own pseudo-codeword (orthogonal to others).
o Receivers detect only the desired codeword. All others appear
as noise.
o Receivers must know transmitter’s codeword.
Advantages:
o Increased capacity
o Improved voice quality
o Eliminating the audible effects of multipath fading
o Enhanced privacy and security
o Reduced average transmitted power
o Reduced interference to other electronic devices
Disadvantages:
o Wide bandwidth per user required
o Precision code synchronization needed
o The Future Planning For Next Semester
o Study the capacity of CDMA
 Study the interference rises from the increasing of capacity and how to reduce its effect
 We will evaluate interference and capacity in CDMA system and analysize them using MatLab simulator