Comparative Study on Spreading Codes

In this paper, we studied on spreading code for wireless communication, their performance analysis, applications and its implementation. Spread-spectrum systems have found important commercial applications in CDMA cellular networks and wireless personal communication networks. Implementation is complex, mainly because spreading the baseband (by a factor that can be several orders of magnitude) forces the electronics to act and react accordingly, which, in turn, makes the spreading and dispreading operation necessary. In spread spectrum the transmission signal bandwidth is much higher than the information bandwidth. The signal occupies a bandwidth much larger than what is necessary to send the information in spread spectrum technology. CDMA uses unique spreading codes to spread the baseband data before transmission data. The performance of a CDMA system gets controlled by two types of interference, namely ISI and MAI which are the function of auto and cross correlation values of the spreading codes respectively. The existing codes using Additive White Gaussian Noise channel under multi-user has been compared with the Bit Error Rate(BER) performance.