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.

Description

CROSS REFERENCE TO RELATED APPLICATION AND CLAIM OF BENEFIT

vie view a predicted measured data.

Another aspect of the present invention uses the signal to total power received ratio to provide a technology independent estimate of the quality of the network design. This aspect of the present invention may also be used to determine areas within the network with the highest interference. Traditionally, interference is calculated in each area of a network based on the implemented frequency plan. This has been done due to the fact that the areas of interference change as the frequency plan changes. However, the present invention allows the system operator to quantify the areas of the network that are likely to have interference problems, regardless of the frequency plan. This aspect of the present invention involves, at each area within the cellular system, calculating the total power received from every base station in the cellular system. Next, the power of the strongest base station for each particular area is compared to the total power received for that particular area. The ratio of these values will range from 0 to 1, or negative infinity to zero when expressed in dB. Frequency assignments are independent of this calculation. The total power received in a location is not the actual power at that location on a given frequency, but rather the total power from all sectors regardless of there frequency assignment.

FIG. 5 is a timing diagram illustrating the FCCH detection aspect of the present invention. The FCCH is transmitted on the BCCH and appears in slot zero of certain of the TDMA frames. An FCCH loaded TDMA frame 500 includes a frequency correction burst 504 and seven data slots 506. To detect the FCCH, 89 bursts of data are recorded, thereby ensuring that the FCB is detected. It is necessary to record 89 bursts due to the fact that the FCB appears only once in every 11 frames. Thus in frame 0, 10, 20, 30, and 40, the FCB appears in slot zero. Periodically, after frame 50, the GSM system will include an idle frame time in which a handoff or other functions can be performed. Thus, the FCB is resumed in frames 51, 61, 71, and 81, which are equivalent to frames 0, 10, 20, 30, and 40. To ensure that a recorded sample includes at least one FCB, the worst case scenario must be taken into account. Thus, 89 burst will include 11 frames and one extra time-slot. This will ensure that in the worst case scenario—beginning a recording that expands across an idle frame in the middle of the burst—at least one FCB is recorded. Traditionally, a mobile unit is provided with the BCC identifying the base station to be tuned to for receiving information. The mobile unit is then aware of which training sequence of the eight possible training sequences to look for. The present invention takes advantage of the fact that the training sequence identifies a particular base station. By capturing the training sequence and correlating the captured training sequence with the 8 possible training sequences, the BCC can be determined. Stated otherwise, the transmitting base station of the received signal can be identified.

In a GSM network with frequency hopping, most operators segregate a set of carriers for BCCH planning. Typically, this set includes between 12 and 18 GSM carriers. Regardless of the number of traffic carriers available to the operator, the number of BCCH carriers set aside determines the reuse factor for BCCH carriers. Even if the majority of mobiles are assigned to non-BCCH (hopping) carriers, the interference on the BCCH carrier is important to the functioning of a GSM network. Mobile devices need good BCCH signals to access the network, make neighbor measurements, and perform handover.

Ideally, a GSM operator would like to use the fewest possible number of carriers as BCCH carriers, because hopping carriers (traffic channel carriers) can be reused much more often and are more efficient from a traffic point of view. There is an engineering trade-off between fewer BCCH carriers—which yields more capacity and causes more interference—and more BCCH carriers which reduces interference but also reduces capacity. Within the scope of carrier-hopping, it can be assumed that there is interference on the BCCH carriers.

However, this does not fully explain the difficulty of performing proper measurements on a GSM network. One aspect of the present invention is to provide hardware that is capable of making comprehensive measurements of every sector in the network, not just find specific occurrences of interference because it can determine which sectors can reuse that are currently not reusing, thus increasing capacity. Accordingly, the hardware should be able to differentiate between two sectors on the same carrier, even when neither of these sectors is actually the serving sector in a given area.

Referring now to FIG. 6, which illustrates an exemplary cell coverage area, in each part of the coverage area of Cell A 605, the signal level of every sector near Cell A 605 needs to be determined. In this example, Cell B 610 and Cell C 615 share the same BCCH carrier as each other, though not the same as Cell A 605. At the identified location in Cell A's 605 coverage, the test equipment should establish the signal level from Cells B 610 & C 615. When using traditional measurement methods, this determination is not possible because Cells B 610 and C 615 interfere with each other. These signals are not interference in the traditional sense, since neither Cell B 610 nor Cell C 615 is actually holding the call, but existing test equipment is not able to determine the signal levels from either sector.

Since there was never an attempt on the part of the frequency planner to limit interference between Cells B 610 and C 615 inside Cell A's 605 coverage area, it can be assumed that this type of interference will happen often, limiting capacity of the network.

There are several types of GSM optimization test equipment currently used. Those skilled in the art are familiar with the operation of the various test equipment currently in use. Most of this test equipment, such as a GSM mobile or a scanner, requires approximately a 9 dB Signal to Noise Ratio (SNR) to accurately decode the BSIC. In such equipment, if the SNR is below 7 dB, the BSIC cannot be decoded, and the current test equipment cannot determine the sources of interference.

A GSM scanner is a test system that rapidly decodes BSICs of GSM signals. In effect, GSM scanners are typically faster testing platforms than standard GSM mobiles, but they do not generally improve the sensitivity. Both scanner and mobile test systems read BSICs and decode them in approximately the same manner.

Consider again the cell layout shown FIG. 6. Table 1 below shows hypothetical signal levels at some point in Cell A's coverage area.

TABLE 1
Example Signal Levels
	Carrier #
Cell	(plan during test)	Signal Level	Potential C/I	comment
Cell A	100	−75 dBm	NA
Cell B	106	−81 dBm	6 dB	No reuse
Cell C	106	−87 dBm	12 dB	Good reuse

The purpose of the testing is to determine whether Cell A 605 can reuse with Cell B 610 and/or Cell C 615. However, traditional test equipment cannot determine that Cell B 610 should not reuse and Cell C 615 can reuse, because it is not possible to decode the color codes of either of those sectors. Considering that the original frequency plan never attempted to reduce interference on carrier 106, in the coverage area of Cell A 605, this situation can be expected to regularly occur. Clearly, if an operator is using 15 BCCH carriers, then at each point existing test equipment does not have the potential to determine the signal levels of more than 15 sectors. Typically the number of determinable signal levels will be significantly fewer, because BSICs will not be detectable.

In a large GSM network with 500 sites and 1500 sectors, each BCCH carrier might be used between 80 and 120 times. Consequently, with traditional test equipment, accurately determining the source of interfering signals difficulties practically impossible.

FIG. 7 is a block diagram of a measurement system according to an exemplary embodiment of the present invention. The measurement system, also referred to as Wireless Interference Detection (WID) is composed of four tools, a collection system 705, a shaper 710, a tunnel 715, and an analyzer 720.

In an exemplary embodiment of the present invention, the WID system allows an operator to make comprehensive coverage measurements for all sectors throughout the network. Within the WID system, each of the four tools performs a separate function. The collection system 705 is a set of hardware that collects raw (unprocessed) RF measurement data in any 10 MHz range from 770 MHz to 2.4 GHz. The shaper 710 is comprised of digital signal processing (DSP) code that detects the existence and power of multiple BCCH carriers on each and every carrier. The tunnel 715 software determines the source (sector) of the detected BCCH carriers, using frequency, timing, and color code. Finally, the analyzer 720 is a set of software tools that allows an engineer to create frequency plans and analyze networks with the measured data.

According to an exemplary embodiment of the present invention, the collection system 705 is responsible for collecting wide-band RF measurements anywhere in a large frequency range. Physically it is composed of two hardware units: the RF front end and the collection computer.

FIG. 8 is a block diagram illustrating an exemplary embodiment of a collection system in accordance with the present invention. In an exemplary embodiment of the present invention the collection system's 705 RF Front End 805 can tune in the range of 770 MHz to 2400 MHz. If multiple ranges are required, the RF front end should be capable of rapidly retuning anywhere in this range. In an exemplary system, the RF front end 805 can retune in less than 10 ms. The RF front end 805 bandwidth is preferably approximately 10 MHz. Generally, the IF signal is centered at 15 MHz, so that the desired signal is in a range from 10 to 20 MHz.

The RF Front-End 805 typically uses a double-conversion approach that minimizes down-conversion harmonics. In an exemplary embodiment of the present invention, the noise figure for the RF Front End 805 is approximately 8 dB for small input signals due to the use of two cascaded Variable Gain Control (VGC) amplifiers. The Data Collection Computer maintains optimal Analog-to-Digital (A/D) performance by controlling the VGC amplifiers, which in turn control the output signal level from the RF Front-End 805 to the A/D converters. The VGC amplifiers use internal voltage controllable attenuators to adjust the amplifier gain level.

In an exemplary embodiment of the present invention, the RF Front End 805 is optimized for a maximum input RF signal level of −12 dBm with minimal signal compression at −8 dBm. These input levels are based on the utilization of a 0 dB gain, 50 ohm telecommunication antenna.

An Automatic Gain Control (AGC) preamplifier gain in the front end is set before data recording is begun in the A/D converter. The AGC gain is set to provide a maximum output of 5 mVolts from the RF Front-End 805.

The collection system 705 includes a collection computer 835, which is responsible for controlling the RF Front End 805, an A/D converter 820, a GPS card 815, other navigation, if used, and for storing the raw RF measurements onto large hard disks 830. The raw RF measurements are analyzed to determine whether the RF transmission was sent from a particular cell.

The RF Front End 805 outputs an Intermediate Signal (IF) of approximately 10 MHz, which is digitized using the A/D converter 820. In an exemplary embodiment of the present invention, the A/D converter 820 is a CompuScope™ A/D operable at 50 Msamples/sec and 12 bit samples. Each sample (12 bits) has a range of ±2047. These values are relative voltage with 2047=+500 mV. Alternatively, other digitizers may be used in accordance with the present invention.

A large set of these samples may be combined with header information to create a snapshot. FIG. 9 illustrates subset of an exemplary snapshot. In the snapshot shown in FIG. 9, the range of voltages into the A/D converter 820 is approximately ±300 mVolt (1200/2047*500 mVolt). This snapshot was taken in close proximity to a base station so that the majority of the signal entering the A/D converter 820 is from one cell site. With the strong signal strength from a single base station, it is easy to see the power-up and power-down of the timeslots. Those skilled in the art are capable of reading snapshots such as the one shown in FIG. 9, and in identifying the signal characteristics present. There are also two traffic channels turning on and off as can be determined by the fact that the first, fifth, and ninth bursts have more power than the others. The traffic channel energy is apparent because the snapshot is of the raw data and is unfiltered.

Along with the raw voltage data, an exemplary snapshot also contains a binary header with location, time, AGC gain, and calibration information.

The collection system includes a GPS unit 815. In an exemplary embodiment of the present invention, a DATUM™ GPS card is used as the GPS unit 815. Alternatively, any system capable of providing GPS data may be used. This card provides location and time information. The control software 810 uses one signal to start the A/D converter and to obtain a location and time stamp from the GPS card 815, simultaneously

The WID Shaper 710 detects very weak BCCH carriers and determines BCCs. The data collection is more thorough and the processing of the data yields more complete and detailed information, which is then used to create an optimized frequency plan for the sector. The DSP process of the shaper 710 performs FCCH Detection, FCCH/SYNCH Correlation, and BCC Detection.

In an exemplary embodiment of the present invention, the FCCH burst consists of all zeros. With the type of modulation and filtering used in GSM, the FCCH appears as an unmodulated signal at 67.7 kHz above the center carrier. Because all of the energy of the FCCH is compressed into a narrow band, the FCCH can be easily detected within the power spectrum.

FIG. 10 illustrates the power spectrum of an FCCH burst, which spikes above the carrier signal at 67.7 kHz. The energy spike can be compared to the average power spectrum of the rest of the burst, which consists of normal bursts, a SYNCH burst and dummy bursts.

From the FCCH detection phase, an approximate position for the FCCH burst may be determined in the snapshot. In order to determine color code, however, it is preferable to determine the exact timeslot format to the accuracy of one bit. The timeslot format is determined by correlating the snapshot against the FCCH burst and the SYNCH training sequence.

The FCCH burst is defined in the GSM specifications as the modulation of all zeros. That is, the FCCH burst is composed of 142 zeros and tail bits, which are also zeros. The SYNCH burst contains information that is always changing. However, the SYNCH burst contains a fixed extra long training sequence as shown in FIG. 11. FIG. 11 is a timing diagram illustrating exemplary FCCH and SYNCH bursts.

Furthermore, in an exemplary embodiment of the present invention, the SYNCH burst occurs exactly eight time slots after the FCCH burst. The shaper 710 creates a template made of the FCCH burst and the SYNCH training sequence. The template is correlated against the recorded data which has been filtered and down-converted to baseband by the shaper 810.

FIG. 12 is a block diagram illustrating the operation of the shaper 710. As shown in FIG. 12, incoming data 1205 is filtered through a band-pass filter 1210, a down converter 1215, and another filter 1220 and then is correlated 1235 to the FCCH Burst 1225 and the SYNCH training sequence 1230 to produce a correlated data sequence 1240.

Because the FCCH burst is all zeros, correlation increases as the template and real FCCH overlap, creating correlation in a pyramid shape. The SYNCH training sequence 1230, however, does not present this type of correlation result. Therefore, a strong FCCH/SYNCH will have a correlation in the shape of a pyramid with a peak on top.

FIG. 13 illustrates the pyramid effect of correlating the FCCH burst for a strong signal. In an exemplary embodiment of the present invention, the FCCH/SYNCH correlation algorithm of the shaper 710 provides an accurate timing structure of the data such that the exact position of each burst is known. In GSM the BCC sets one of eight training sequences that are used for normal bursts. The training sequences for normal bursts are 26 bits long as shown in FIG. 14.

In an exemplary embodiment of the present invention, the DSP algorithm in the shaper 710 correlates each of the eight possible training sequences against the location of the training sequence of the data for every burst that does not appear to be a dummy burst.

FIG. 15 is a block diagram of a correlation algorithm in an exemplary embodiment of the present invention. As shown in FIG. 15, data 1505 is filtered through a band-pass filter 1510, a down converter 1515, a filter 1520, and correlated 1530 to the dummy burst 1525. If the data 1505 correlates to the dummy burst 1525 within an acceptable threshold, the next burst 1540 is analyzed. In an exemplary embodiment of the present invention, an acceptable threshold may. If the data 1505 does not sufficiently correlate to the dummy burst 1525, it is correlated 1545 to training sequence templates 1550. The correct training sequence is then selected by determining the sequence with the highest average correlation 1555. Very high processing gain is achieved through the averaging of the correlation results for as many as 86 bursts.

The output of the Shaper 710 DSP algorithm 1500 is a list of detected BCCH carriers, their signal levels and information used to determine the source of the signal. This information preferably includes, but is not limited to, the BCCH carrier, BCC, time of arrival, and location of measurement.

FIG. 16 is a flow diagram illustrating an assignment procedure in accordance with an exemplary embodiment of the present invention. As shown in FIG. 16, the assignment procedure involves (1) creating a reference table containing known reliable measurements and the name (code) of the sector from which they were received 1605; (2) processing these references to determine any base station clock error 1610; and (3) for each measurement determining the source of the signal by using BCCH carrier frequency and time of arrival 1615. Step 1615 is performed by comparing the measurement to the closest reference. If they match and it is the only one that does, then the measurement came from the sector with that reference.

The WID Analyzer 720 is a set of software tools that allows an engineer to process and view measurement information. The analyzer 720 includes an Automatic Frequency Planning Algorithm (AFP) used to create optimal BCCH and hopping plans.

In an exemplary embodiment of the present invention, a reference table is created containing known arrival times for FCCH bursts (i.e. BCCH carriers and their timing structure) and the sector that sent them.

In an exemplary embodiment of the present invention, the reference table is created using an algorithm that searches through a list of potential BCCH carriers, and chooses those that meet user defined criteria. Alternatively, a reference file may be created by taking measurements close to a transmission tower in each cell or sector. These measurements are highly reliable because the signal strength of the close by tower will be much stronger than any potentially interfering signals. Alternatively, the reference file may be created using known data. Additionally, the reference file may be created through statistical analysis of captured transmission data. By analyzing the data, one skilled in the art may identify highly reliable signals and assign them to the reference file.

The Reference Table is processed to determine if the timing of each reference assigned to a sector is consistent with the timing of other references assigned to that sector. Inconsistencies are reported to the user for investigation. Also, the references may be analyzed to determine any clock error at the base station. This clock error may be accounted for when making assignments.

In an exemplary embodiment of the present invention, raw RF measurements are stored during data capture. These measurements may then be analyzed to determine the cell from which a the RF signal was sent. This determination is made by comparing the time data with data in the reference file. In an exemplary embodiment of the present invention, one may determine whether two signals originated from the same cell by calculating whether the FCCH burst occurred in the correct frame with the correct color code. For example, the FCCH burst is guaranteed to reoccur ever 51 frames and will also reoccur every 10 or 11 frames (depending on the presence of the idle frame). Accordingly, using a known reference in the reference file, one may determine whether a later FCCH burst likely was sent from the same cell. In an exemplary embodiment of the present invention, the system determines that the FCCH burst was sent from the same cell if it occurred in a time slot corresponding to a multiple of 51 frames later. Additionally, the system may determine that an FCCH burst occurring 10, 11, 20, 21, 30, 31, 40, or 41 time slots before or after an FCCH burst in the reference file.

Preferably, the system first narrows the field of potential cells by identifying the cells that broadcast on the same frequency as the received burst. Then, using the timing of the FCCH burst, the system identifies a most likely, or a set of likely, transmitting cells.

When assigning measurements, an exemplary embodiment of the present invention may require that the time of arrival of the FCCH burst is consistent with the reference closest in time with the candidate measurement given the (1) calculated clock error of the sector; (2) margin given the accuracy of our time measurement; and (3) difference in distance between the reference and the measurement to take into account the speed of light.

The system may also estimate the power in each FCCH burst (BCCH carrier) by looking at the peak power from the FCCH detection. The system may create a metric called Bandpow Ratio. This is calculated by taking the peak power and dividing by the power across the carrier. Accordingly, the denominator used to divide is the total power from ±˜50 KHz around the center frequency. A strong FCCH burst would show a high peak power and a low power across the band, thus a high Bandpow Ratio. The system may also use the Bandpow Ratio to make power estimation more accurate.

The BCCH time slot (time slot 0) on the BCCH carrier generally has a repeating structure of 51 frames. Frames 0, 10, 20, 30, 40 contain the FCCH burst. Frame 50 is an idle frame. Following Frame 50, the cycle repeats. This means that whenever there is an FCCH burst, there is another 51 frames later regardless of when the idle frame is. To get better sensitivity in the FCCH detection phase, the system takes RF signal data spaced by exactly 51 frames, either by taking two snapshots spaced by 51 frames or by taking a very long snap shot of more than 51 frames. The FFTs may be combined in such a way that real FCCH burst peaks will combine while random peaks will not.

In a synchronized network, sectors may use identical timing structures. Thus, their references would be the same. In such a network, assignment may be made by calculating the signal delay given the speed of light.

The dummy burst 1525 is a known set of 148 bits and is sent on the BCCH carrier during time slots 1-7 whenever there is not user data or voice to send. This means that there could be very many of them during a snapshot, which may, for example, contain 89 bursts. By correlating against a known dummy burst, very accurate timing can be obtained for the BCCH carrier. This would allow assignment to be made even on a synchronized network by using propagation delay.

Timing advance data may be sent to a mobile device on a GSM network. When the mobile device moves further away from a cell site, signals are received with greater delay. Since the mobile device get its timing structure from what it receives, it may send its data or information late. Due to the distance, the signal may be even more delayed, thus arriving in the next time slot. An exemplary embodiment of the present invention uses timing advance to take into account the signal path length, which can be more than the distance between the mobile and the site, if the main signal is the result of a reflection.

While the present invention has been described in detail with particular reference to exemplary embodiments thereof, it will be understood that variations and modifications can be effected within the scope of the invention as defined in the appended claims.

Claims

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;

correlating comparing 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;

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 determine determining 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 determine the 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.