MATLAB Simulation of CDMA Signal Processing: Encoding, Modulation, and Demodulation Workflow

This MATLAB simulation demonstrates CDMA signal processing, including complex workflows such as signal encoding, modulation, and demodulation. The simulation implements CDMA technology to achieve signal transmission and communication between multiple users. First, signals undergo encoding using techniques like Walsh codes or PN sequences to ensure proper identification and decoding during transmission. MATLAB's Communications Toolbox provides functions like `walshCode` and `pnSequence` for generating orthogonal codes that enable multiple access capability. The encoded signals then undergo modulation processes such as QPSK or BPSK, converting them into analog or digital formats suitable for transmission. Key MATLAB functions like `pskmod` and `comm.PSKModulator` implement modulation algorithms with configurable parameters for carrier frequency and symbol mapping. At the receiver end, the simulation performs demodulation using matching functions like `pskdemod` and subsequent decoding to recover the original signals. The implementation includes error detection/correction mechanisms and uses correlation techniques with `xcorr` function for code synchronization. Through this simulation, users can deeply understand CDMA signal processing principles, including spread spectrum techniques, orthogonal coding algorithms, and multi-user detection methods, while gaining practical MATLAB implementation experience for wireless communication systems.