The neighboring frequency interference refers to the signal interference from the adjacent frequency of the signal frequency used. The adjacent frequency interference is due to the unsatisfactory receiving filter, which causes the signal of adjacent frequencies to leak into the transmission bandwidth. The adjacent frequency interference can be minimized by precise filtering and channel allocation.
Near-far effect: if the base station of the neighboring channel is launched in a range close to the user receiver, and the receiver uses the base station signal of the preset channel, this problem becomes very serious, which is called near-far effect. Near the base station when the channel used by the mobile station and a weak signal mobile channel for the adjacent channel, also occurs near and far effect. (in UMTS system, because all mobile stations use the same frequency band, far and near effect is more obvious, but the UMTS system uses good power control to eliminate the effect of near-far effect).