Method and apparatus for measurement and identification of co-channel interfering transmitters
First Claim
1. A method for measurement and identification of base stations transmitting on the same channel, thus interfering with each other, in a GSM cellular wireless network wherein a plurality of base stations each transmit a 51-multiframe signal including a plurality of FCCH bursts, a plurality of SCH bursts and a plurality of BCCH bursts, the method comprising:
- a) receiving signals within the intended coverage zone of the GSM cellular wireless network;
b) correlating the received signals with an FCCH burst waveform signal to identify a set of FCCH correlation peaks therein;
c) for each given FCCH correlation peak within said set of FCCH correlation peaks, generating data representing time-of-arrival and power level for the given FCCH correlation peak, and adding said data to a data file;
d) for at least one given FCCH correlation peak within said set of FCCH correlation peaks, scheduling SCH burst decoding operations for a time window derived from the time-of-arrival of the given FCCH correlation peak;
e) performing SCH burst detection and decoding operations on said signals during each time window scheduled in d) to thereby identify BSIC data and RFN data encoded in a given SCH burst detected within said signal, and adding time-of-arrival data, said BSIC data and a frame number data based on said RFN data for the given SCH burst to the data file; and
f) for each given SCH burst successfully detected and decoded in e), identifying a plurality of time-of-arrival windows within the 51-multiframe based upon the time-of-arrival data and frame number data of the given SCH burst, and updating the data file to associate the BSIC data and frame number data for the given SCH burst with the power level data for each FCCH correlation peak whose time-of-arrival falls within said plurality of time-of-arrival windows of the 51-multiframe.
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Accused Products
Abstract
A methodology and apparatus for measurement and identification of co-channel interferers in a GSM cellular wireless communication network is provided as part of a network survey (e.g., drive test). Repetitive time-of-arrival measurements of detected FCCH bursts on a given frequency channel are made in conjunction with power level and C/I ratio measurements of such FCCH bursts. Successful FCCH burst detection triggers SCH detection/decoding and successful SCH decoding triggers BCCH detection/decoding. Successfully decoded SCH BSIC data and possibly BCCH CellId data is associated with the corresponding FCCH burst information based on their time-of-arrival. This association is possible even with the FCCH bursts for which SCH and BCCH decoding was not successful due to the interference or some other impairment. It is sufficient to successfully decode SCH/BCCH only once per cell during the network survey in order for all detected FCCH bursts coming from this cell to be properly assigned to it. This does not requiring a priori knowledge of the network configuration or its geographical layout. Such methodology (and apparatus) can readily be adapted for other Time-Division-Multiple-Access (TDMA) cellular wireless networks.
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Citations
53 Claims
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1. A method for measurement and identification of base stations transmitting on the same channel, thus interfering with each other, in a GSM cellular wireless network wherein a plurality of base stations each transmit a 51-multiframe signal including a plurality of FCCH bursts, a plurality of SCH bursts and a plurality of BCCH bursts, the method comprising:
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a) receiving signals within the intended coverage zone of the GSM cellular wireless network;
b) correlating the received signals with an FCCH burst waveform signal to identify a set of FCCH correlation peaks therein;
c) for each given FCCH correlation peak within said set of FCCH correlation peaks, generating data representing time-of-arrival and power level for the given FCCH correlation peak, and adding said data to a data file;
d) for at least one given FCCH correlation peak within said set of FCCH correlation peaks, scheduling SCH burst decoding operations for a time window derived from the time-of-arrival of the given FCCH correlation peak;
e) performing SCH burst detection and decoding operations on said signals during each time window scheduled in d) to thereby identify BSIC data and RFN data encoded in a given SCH burst detected within said signal, and adding time-of-arrival data, said BSIC data and a frame number data based on said RFN data for the given SCH burst to the data file; and
f) for each given SCH burst successfully detected and decoded in e), identifying a plurality of time-of-arrival windows within the 51-multiframe based upon the time-of-arrival data and frame number data of the given SCH burst, and updating the data file to associate the BSIC data and frame number data for the given SCH burst with the power level data for each FCCH correlation peak whose time-of-arrival falls within said plurality of time-of-arrival windows of the 51-multiframe. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A data analysis tool that measures and identifies base stations transmitting on the same channel, thus interfering with each other, in a GSM cellular wireless network wherein a plurality of base stations each transmit a 51-multiframe signal including a plurality of FCCH bursts, a plurality of SCH bursts and a plurality of BCCH bursts, the data analysis tool comprising:
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a) means for receiving signals within the intended coverage zone of the GSM cellular wireless network;
b) means for correlating the received signals with an FCCH burst waveform signal to identify a set of FCCH correlation peaks therein;
c) means for generating data representing time-of-arrival and power level for each given FCCH correlation peak within said set of FCCH correlation peaks, and adding said data to a data file;
d) means for scheduling SCH burst decoding operations for a time window derived from the time-of-arrival for at least one given FCCH correlation peak within said set of FCCH correlation peaks;
e) means for performing SCH burst detection and decoding operations on said signals during each time window scheduled by d) to thereby identify BSIC data and RFN data encoded in a given SCH burst detected within said signal, and for adding time-of-arrival data, said BSIC data and a frame number data based upon said RFN data for the given SCH burst to the data file; and
f) means for identifying a plurality of time-of-arrival windows within the 51-multiframe of each given SCH burst successfully detected and decoded by e), and for updating the data file to associate the BSIC data with the power level data for each FCCH correlation peak whose time-of-arrival falls within said plurality of time-of-arrival windows within the 51-multiframe of the given SCH burst. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41)
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42. A method for measurement and identification of base stations transmitting on the same channel, thus interfering with each other, in a cellular wireless network wherein downstream signals from base stations to users are communicated in frames and include fixed signal waveforms and information that identifies base stations, the method comprising:
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a) receiving signals within the intended coverage zone of the cellular wireless network;
b) detecting known signal waveforms in the received signals;
c) for each detected signal waveform, logging time-of-arrival and power level data for the detected signal waveform to a data file;
d) detecting and decoding data that identifies a base station in the cellular wireless network; and
e) identifying a plurality of time-of-arrival windows based on data generated in d), and updating the data file to associate the data generated in d) with power level data of detected signal waveforms whose time-of-arrival falls within said plurality of time-of-arrival windows. - View Dependent Claims (43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53)
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Specification