Performance evaluation of an OFDMA and CDMA overlaid system

The overlay systems appear due to the evolution of the mobile telephony, in fact currently exist 3G and 4G simultaneously, for this reason the impact and feasibility of an OFDMA cellular system overlaid is studied. 3G systems based on CDMA offer important characteristics and services to the users, besides a good capacity and service quality. 4G systems are the most recent technology and are based on OFDMA that is considered as the evolution of CDMA. OFDMA has demonstrated to have good efficiency, robustness to several channel effects and response to interference. In fact we are living the migration from 3G to 4G systems. In this work we evaluate the impact of this overlay situation.