Method for interference source identification

The present invention relates to a method to identify one or more interference sources in a mobile radio system, preferably in a GSM radio network for mobile telephones. A received signal (r) consists of a wanted signal and a number of interference signals of which one is a dominating interference signal and where all signals includes a known training sequence (TK 1 ,TK 2 , . . . ). The carrier is estimated and subtracted from the received signal (r) giving a remaining interference signal (s).This signal is correlated against known training sequences (TKj, j=0,1,2, . . . ,7) resulting in a training sequence associated with the interfering signal. According to the invention, the identification code (BCC) of a possible interference source (BS1) from said training sequence is determined. After that, a number of candidates (CA 1 ,CA 2 , ), each corresponding with a certain cell from the identification code (BCC) are determined and also the frequency which is disturbed and the timing offset (t 1 ,t 2 , . . . <FIGREF IDREF="DRAWINGS">FIG. 7</FIGREF>) for the frequencies used by said candidates. Finally it is investigated if one or more (fa,fb) of these have the same time offset as the interference signal (t 0 ) resulting in that at least one candidate (CA 3 ) with the best matching offsets on its frequencies is identified as the interference source.