how to implement a multi user communication system?

i have implemented a single user WCDMA communication link with a transmitter, AWGN channel and a receiver using Qpsk modulation technique and spreaded using a PN sequence. I need to make this a multi user communication link.

By that is it possible to do that using a MUX and a DEMUX before and after the AWGN channel?? What specific parameters i have to change??

Please Help..

Answer 1

[Anshuman]

You can extend your single-user WCDMA communication link to a multi-user communication link by using a MUX (multiplexer) and DEMUX (demultiplexer) before and after the AWGN channel. Here are the key steps and parameters to change:

Steps to Implement Multi-User WCDMA Communication Link

1. Define Multiple Users: Each user will have their own data stream, PN sequence, and QPSK modulator.
2. Multiplex the Users: Use a MUX to combine the multiple user data streams into a single stream before the AWGN channel.
3. Add AWGN Channel: The combined signal will pass through the AWGN channel.
4. Demultiplex the Users: Use a DEMUX to separate the combined signal back into individual user signals after the AWGN channel.
5. Process Each User Signal: Each user signal will be processed individually through their respective QPSK demodulator and PN sequence despreader.

Key Parameters to Change

1. Number of Users: Define the number of users in your system.
2. PN Sequences: Each user should have a unique PN sequence to ensure orthogonality and minimize interference.
3. Data Streams: Generate separate data streams for each user.
4. Multiplexer and Demultiplexer: Use a MUX to combine the user data streams before transmission and a DEMUX to separate them after reception.

Hope it helps!