Adjacent channel interference in WCDMA networks equipped with multiple antennas mobile stations

The purpose of this work is to show to what extent multiple antenna terminals can combat inter-operator interference in WCDMA networks. To this end, a realistic modeling of adjacent channel interference-including filters imperfections and power amplifier nonlinearities is considered. Adjacent channel interference creates dead zones where the QoS target cannot be reached. We first characterize these zones in terms of radius and probability of finding a given amount of users in it. In this respect, an interesting result is that the probability of finding one user in a dead zone can reach 48% for a 50% user load. But the main contribution is to show that certain linear multiantenna reception schemes are able to cope with ACI. Compared to a conventional ID Rake, the dead zone radius is decreased from 80 m to 20 m for typical NLOS scenarios. The results are far more significant when the interfering adjacent band operator has a LOS channel, the bit error rates is decreased from 50% to 0.1% around the interfering BS. At last, the best choice of the linear receiver scheme is discussed regarding propagation conditions (power delay profile, power angle profile, antenna correlation).