Adjacent channel interference in UMTS systems in the 2000 MHz and 2500 MHz bands

The purpose of this paper is to evaluate the impact of adjacent channel interference in network coverage and capacity, and find a strategy to minimize it. This strategy consists of identifying the optimal spacing between adjacent carriers in the radio spectrum available for use. To define this strategy, first the issue of dead zones is analyzed. Here, for different spacing between adjacent carriers, the size of dead zones is calculated. It s concluded that for a carrier separation of 10 MHz the dead zones are almost inexistent, and that it can be eliminated by colocalizing the base stations. To analyse the impact of the adjacent channel interference in the network capacity, several simulations are done, using a static simulator, for different types of scenarios. The simulations are done considering both the 2000 MHz and the 2500 MHz bands. It was noticed that, for both bands, when there is a high number of BS, the impact of adjacent channel interference is minimal, due to a more significant interference coming from BS/MT operating in the same frequency. It was also concluded that the macro carrier should be placed in the centre of an operator’s available spectrum and that, when micro and macro BS operate in adjacent channels, those should be separated by 10 MHz, in order to minimize the losses in the capacity of both operators. KeywordsHSDPA, HSUPA, adjacent channel interference, dead