System and method for identifying co-channel interference in a radio network

Abstract

The present invention is directed toward a system and method for identifying co-channel interference in a radio network. In an exemplary method according to the present invention, a first stream of transmission data having a first received signal frequency at a first reception location for a first period of time is received. Further, the first signal frequency of the first stream of transmission data is identified. Then the transmission data is correlated against a signal template to identify a first FCCH burst frame. Then, first FCCH time data corresponding to the first FCCH burst frame is identified and the signal frequency of the first stream of transmission data and the first FCCH time data is compared to a reference file to determine one or more probable transmission cells.

1. A method of detecting a transmission from a primary cellular transmitter, the primary cellular transmitter transmitting on at least one channel frequency and being located in the vicinity of one or more secondary cellular transmitters, the method comprising the steps of:
 receiving a first stream of transmission data having a first received signal frequency at a first reception location for a first period of time; 
 identifying the first signal frequency of the first stream of transmission data; 
 correlatingcomparing the first stream of transmission data against a signal templateplurality of predetermined burst structures to identify a first FCCH burst frame, the predetermined burst structures comprising at least one burst structure that includes a plurality of fixed bits in succession that indicate a training sequence; 
 identifying first FCCH time data corresponding to the first FCCH burst frame; and 
 comparing the first signal frequency of the first stream of transmission data and the first FCCH time data corresponding to the first FCCH burst frame to a reference file, the reference file comprising a plurality of reliable measurements and a transmission cell sector corresponding to where each reliable measurement was received; and  
 to determinedetermining one or more probable transmission cells based on the comparison. 
 
     
     
       2. The method of  claim 1 , where further comprising: comparing the first signal frequency and the first FCCH time data corresponding to the first FCCH burst frame to the reference file comprises that comprises a plurality of data entries representative of, wherein the data entries represent a plurality of reference signal frequency data entries and a plurality of reference FCCH time data entries for a plurality of transmission cells. 
     
     
       3. The method of  claim 2 , wherein the step of comparing the first signal frequency of the first stream of transmission data and the first FCCH time data to a reference file to determine a probable transmission cell comprises the steps of: further comprising: 
 identifying each transmission cell in the reference file, wherein the identification is made using substantially the same frequency as the first received signal frequency received in the first stream of transmission data; and 
 analyzing the reference FCCH time data entries for each cell using substantially the same frequency as the first received signal frequency to determine; and identifying transmission cells with reference FCCH time data entries corresponding to the first FCCH time data. 
 
     
     
       4. The method of  claim 3 , wherein the FCCH time data entries corresponds to the first FCCH time data if the first FCCH time data represents a time frame occurring a multiple of 51 time frames apart from the reference time data. 
     
     
       5. The method of  claim 3 , wherein the FCCH time data entries corresponds to the first FCCH time data if the first FCCH time data represents a time frame occurring 10 time frames from a time frame occurring a multiple of 51 time frames apart from the reference time data. 
     
     
       6. The method of  claim 3 , wherein the FCCH time data entries corresponds to the first FCCH time data if the first FCCH time data represents a time frame occurring 11 time frames from a time frame occurring a multiple of 51 time frames apart from the reference time data. 
     
     
       7. The method of  claim 3 , wherein the FCCH time data entries corresponds to the first FCCH time data if the first FCCH time data represents a time frame occurring 20 time frames from a time frame occurring a multiple of 51 time frames apart from the reference time data. 
     
     
       8. The method of  claim 3 , wherein the FCCH time data entries corresponds to the first FCCH time data if the first FCCH time data represents a time frame occurring 21 time frames from a time frame occurring a multiple of 51 time frames apart from the reference time data. 
     
     
       9. The method of  claim 3 , further comprising the steps of: if more than one transmission cell is identified for which the reference FCCH time data entries corresponds to the first FCCH time data, then identifying first geographic location data associated with the first reception location; and comparing the first geographic location data with and location data associated with each identified transmission cell to determine a most probable transmission cell. 
     
     
       10. The method of  claim 1 , wherein the step of identifying first location data comprises further comprising: identifying first geographic location data by receiving location data from a GPS unit. 
     
     
       11. The method of  claim 1 , where the first period of time is of sufficient duration to record sixty-two frames of transmission data. 
     
     
       12. The method of  claim 1 , further comprising comparing the first stream of transmission data against the plurality of predetermined burst structures to identify the first FCCH burst frame, wherein the signal template comprises plurality of predetermined burst structures comprise an FCCH Burst and a SYNCH training sequence. 
     
     
       13. The method of  claim 1 , wherein the step of further comprising identifying time data corresponding to the first period of time comprises by receiving time data from a GPS unit. 
     
     
       14. A system for detecting a transmission from a primary cellular transmitter, the primary cellular transmitter transmitting on at least one channel frequency and being located in the vicinity of one or more secondary cellular transmitters, the system comprising:
 an RF front end adapted to receive a first stream of transmission data having a first signal frequency at a first reception location for a first period of time; 
 the RF front end further adapted to identifying the first signal frequency of the first stream of transmission data; 
 a shaper adapted to correlate compare the first stream of transmission data against a signal template plurality of predetermined burst structures to identify a first FCCH burst frame, the predetermined burst structures comprising at least one burst structure that includes a plurality of fixed bits in succession that indicate a training sequence; 
 the shaper further adapted to identify identifying first FCCH time data corresponding to the first FCCH burst frame; and 
 an analyzer adapted to compare comparing the first signal frequency of the first stream of transmission data and the first FCCH time data corresponding to the first FCCH burst frame to a reference, the reference file comprising a plurality of reliable measurements and a transmission cell sector corresponding to where each reliable measurement was received; and  
 to determinethe analyzer determining a probable transmission cell based on the comparison. 
 
     
     
       15. The system of  claim 14 , wherein the reference file comprises a plurality of data entries representative of, wherein the data entries represent, wherein the data entries represent reference signal frequency data entries and a plurality of reference FCCH time data entries for a plurality of transmission cells. 
     
     
       16. The system of  claim 14 , wherein the analyzer is further adapted to: identify identifies each transmission cell in the reference file that uses, wherein the identification is made using substantially the same frequency as the first signal frequency received in the first stream of transmission data; and analyze wherein the analyzer analyzes the reference FCCH time data entries for each cell using substantially the same frequency as the first signal frequency to determine identify transmission cells with reference FCCH time data corresponding to the first FCCH time data. 
     
     
       17. The system of  claim 16 , wherein the FCCH time data entries corresponds to the first FCCH time data if the first FCCH time data represents a time frame occurring a multiple of 51 time frames apart from the reference time data. 
     
     
       18. The system of  claim 16 , wherein the FCCH time data entries corresponds to the first FCCH time data if the first FCCH time data represents a time frame occurring 10 time frames from a time frame occurring a multiple of 51 time frames apart from the reference time data. 
     
     
       19. The system of  claim 16 , wherein the FCCH time data entries corresponds to the first FCCH time data if the first FCCH time data represents a time frame occurring 11 time frames from a time frame occurring a multiple of 51 time frames apart from the reference time data. 
     
     
       20. The system of  claim 16 , wherein the FCCH time data entries corresponds to the first FCCH time data if the first FCCH time data represents a time frame occurring 20 time frames from a time frame occurring a multiple of 51 time frames apart from the reference time data. 
     
     
       21. The system of  claim 16 , wherein the FCCH time data entries corresponds to the first FCCH time data if the first FCCH time data represents a time frame occurring 21 time frames from a time frame occurring a multiple of 51 time frames apart from the reference time data. 
     
     
       22. The method of  claim 14 , wherein the signal template plurality of predetermined burst structures comprises an FCCH Burst and a SYNCH training sequence. 
     
     
       23. The method of claim 1, wherein the reference file contains base station color codes. 
     
     
       24. The method of claim 1, wherein the reference file contains signal data for transmission cells for which the base station color were decoded. 
     
     
       25. The method of claim 1, wherein the reference file contains data uniquely identifying each of the one or more probable transmission cells. 
     
     
       26. The method of claim 1, wherein the reference file is created prior to receiving the first stream of transmission data. 
     
     
       27. The method of claim 1, wherein each entry in the reference file for a transmission cell is created from measurements taken in proximity to the base of a transmission tower associated with the transmission cell. 
     
     
       28. The method of claim 1, wherein the comparison occurs after all streams of transmission data for a test drive data have been received. 
     
     
       29. The method of claim 1, wherein determining one or more probable transmission cells of the first stream of transmission data comprises comparing the first FCCH time data to time data for one or more transmission cells in the reference file. 
     
     
       30. The method of claim 14, the shaper further adapted to create a template from an FCCH burst frame and a SYNCH training sequence and correlate the template against a first stream of transmission data filtered and down-converted to baseband by the shaper. 
     
     
       31. The method of claim 14, the shaper further adapted to output a list of detected BCCH carriers, signals levels of the BCCH carriers, and information used to determine each source of each signal containing a BCCH carrier.