Enhancement of code division multiple access system performance using raptor codes

Some kinds of communication systems work in very low signal-to-noise (LSNR) environments. For these to function reliably, <span>specific techniques and methodologies have be used mitigate the degrading effects channel. The channel coding method is key element most LSNR systems, but emphasizing code division multiple access (CDMA) a new transmission technique channels. To enhance CDMA scheme's system capacity reach unprecedented ranges values wireless sensor network. This paper suggests combining with certain types algorithms, such as raptor codes. encoding has improved system's performance when using binary phase-shift keying (BPSK) modulation additive white gaussian noise (AWGN) It achieved bit error rate range 10-7 at Eb/No value (-3) dB about 10-6 shannon's limit. Raptor-coded scheme works well for signal ration (SNR) greater than -9 dB, showing an improvement 7 compared turbo/convolutional methods (BER) throughput. On other hand, it been shown that convolutional encoder presents weakest both turbo codes.</span>