18. The method of claim 13 , wherein the comparing the detected user's voice signal with voice signal patterns from at least one model comprises calculating a first probability that the user's voice matches the voice patterns in a first model, and calculating a second probability that the user's voice matches the voice patterns in a second model.
18. The method of claim 13 , wherein the comparing the detected user's voice signal with voice signal patterns from at least one model comprises calculating a first probability that the user's voice matches the voice patterns in a first model, and calculating a second probability that the user's voice matches the voice patterns in a second model. 23. The method of claim 18 , further comprising recognizing the user's voice if a ratio of the first probability and the second probability is equal to or greater than the first reference value.