The impact of intermodulation on downlink of WCDMA systems

In this paper, the impact of intermodulation (IMD) on the downlink of WCDMA systems was studied. IMD decreases the cell coverage and network capacity of wideband CDMA systems. Extensive simulations were used to analyze the impact of IMD in user equipments (UEs) and the contribution of IMD interference to the total interference. In worst-case scenarios, it is shown that the downlink outage rate could be very high and the cell coverage may shrink seriously due to IMD. Thus the stability of the system might be affected and converged results could not be obtained. A novel approach was adopted to deal with the instability of the systems in these scenarios and obtain statistical results based on the approach. The results show that the capacity loss decreases exponentially as IIP₃ increase and the contribution of IMD interference to the total interference also decreases as IIP₃ increases. The approach adopted in this paper could be utilized in the study of various topics and our results provide meaningful insights for the design of WCDMA networks.