BER and LLR Analysis with MC-CDMA using BPSK/QAM Techniques for Wireless Communication

In recent years CDMA becomes most widely used spread spectrum technique in wireless communication system because MC-CDMA allows multiple users to share the same frequency spectrum simultaneously. In this paper, generating an input signal and modulating it using MCCDMA.After the modulation of signals, different noises are added to the modulated signal. And checking the received signal, BER, SNR, checks the fidelity of the transmitted signal. Noises are added because when the signal is generated in the transmitted channel the signal is affected due to noises. The reasons of these improvements have been explained analytically and the simulations results verified the analytical results. There are several modulation schemes such as BPSK; QPSK and QAM. For providing different data rates, modulation schemes are using along with MC-CDMA technique. Keywords—MC-CDMA (Multi-Carrier Code Division Multiple Access), QAM (Quadrature Amplitude Modulation, BER (Bit Error Rate), SNR (Signal-to-Noise Ratio), LLR (Log Likeli-Hood Ratio)