OFDM combined with W-CDMA underlay digital transmission

In this paper an underlaid network consisting of an OFDM primary user and a W-CDMA secondary user was examined. The underlaid netowrk is proposed as a way of increasing the efficient use of the radio spectrum. Both multi-carrier transmission techniques offer different pros and cons which will be exploited within this network to increase spectrum efficiency. In addition to increased throughput, the underlay network can increase OFDM's high sensitivity to frequency synchronisation issues by transmitting the pilot packets through the W-CDMA channel. This results in higher secured throughput by adding small interference margins to both users. An investigation will be conducted to see what the interference levels will be within the network, both on the OFDM and the W-CDMA; and how much increase in secure throughput will be gained. The underlaid network will be modelled and simulated in MATLAB.