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CDMA
This document discusses Code Division Multiple Access (CDMA), a type of multiple access technology that allows multiple users to access a single radio channel simultaneously. CDMA separates users by assigning each user a unique code, called a chip code. At the transmitter, the input signal is multiplied by the chip code and modulated onto a carrier signal before transmission. At the receiver, the received signal is correlated with the same chip code to recover the original data signal. CDMA has advantages over other multiple access techniques as it does not impose restrictions on time or bandwidth and optimizes the use of available wireless spectrum.
CDMA
- 1. CDMASUBMITTED TO :Mrs. Chitra Biswas Lecturer, Dept. of ETE, FSET, USTC SUBMITTED BY : Ananda Mohan Shil 6th semester, EEE, ID : 15010324
- 2. MULTIPLE ACCESSING MORETHAN ONE USER HAS ACCESS TO ONE OR MORE RADIO CHANNEL USE A SINGLE SATELLITE COMMUNICATION CHANNEL 3 TYPES OF M.A FDMA TDMA CDMA
- 3. CODE-DIVISION MUTIPLE ACCESS(CDMA) NORESTRICTION ON TIME OR BANDWIDTH ALSO CALLED SPREAD-SPECTRUM MULTIPLE ACCESS SEPARATED THROUGH ENVELOPE ENCRYPTION-DECRYPTION TECHNIQUES EARTH STATIONS ENCODED WITH A UNIQUE BINARY WORD CALLED A CHIP CODE
- 4. ENCODER PCM- ENCODED VOICEBAND SIGNALS USED AS INPUT SIGNAL MULTIPLIED BY A UNIQUE CHIP CODE PSK MODULATES AN IF CARRIER UP CONVERTED TO RF FOR TRANSMISSION
- 5. DECODER RF ISDOWN CONVERETED TO IF A COHERENT PSK IS RECOVERED SYCHRONOUS CHIP CODE MUST NEEDED
- 6. CHIP CODE MULTIPLIESRECOVERED PSK CARRIER PSK MODULATED SIGNAL = PSK CARRIER + CHIP CODE IF SIGNAL CONTAINS CHIP CODE , PSK CARRIER & THE DATA INFORMATION IS COMPARED WITH THE RECEIVED IF SIGNAL IN CORRELATOR RESULTANT DATA FROM CORRELATOR = (RECOVERED PSK CARRIER + CHIP CODE) – (RECEIVED PSK CARRIER + CHIP CODE + DATA)
- 7. USES OF CDMA refersto any of several protocols used in second-generation (2G) and third-generation (3G) wireless communications. allows numerous signals to occupy a single transmission channel optimizing the use of available bandwidth.
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