pnseqcdma.m

Sending of data using pn sequence

For Transmitter
1. There are two different message signals of same length, each corresponding to an
individual user.
2. Now, converting each message signal into NRZ format.
Dept. of Electronics and Communication 19
3. Generation of PN sequences for both user, this PN sequence will act as a key for both
transmitting and receiving end.
4. Now, again converting PN sequences into NRZ format.
5. Spreading of message signal1 (user 1) by PN code1.
6. Spreading of user1 message signal is done by the Direct Sequence spreading.
7. Spreading of message signal2 (user 2) by PN code2.
8. Spreading of user2 message signal is done by the Direct Sequence spreading.
9. Addition of the both spread signal to form composite signal.
10. Now this composite signal is BPSK modulated.
11. Transmitting BPSK modulated signal using an AWGN channel at SNR=10.
4.2.2 For Receiver
1. At receiver side, Despreading of received signal for the user 1 by using PN code of
user 1.
2. This PN code works as key for the message signal of user 1.
3. BPSK Demodulation of despreaded signal of user1.
4. Synchronization of data of user1 i.e., Summation of each row of the BPSK
demodulated data of user 1.
5. Converting each analog data into digital data.
6. These converted data is similar to the original message signal of user1.
7. Despreading of received signal for the user 2 by using PN code of user 2.
8. This PN code works as key for the message signal of user 2.
9. BPSK Demodulation of despreaded signal of user2.
10. Synchronization of data of user2 i.e., Summation of each row of the BPSK
demodulated data of user 2.
11. Converting each analog data into digital data.
12. These converted data is similar to the original message signal of user2.