CN111446983B - Multipath searcher, cell search device and cell search method - Google Patents

Abstract

The present disclosure relates to a multipath searcher, a cell search apparatus, and a cell search method. The multipath searcher comprises: the device comprises a path searching module, a path searching module and a path searching module, wherein the path searching module is connected with a PSC correlator and used for determining a plurality of paths to be screened according to a plurality of target correlation values obtained from the PSC correlator; and the diameter screening module is connected with the diameter searching module and used for eliminating invalid diameters from the multiple diameters to be screened to obtain multiple target diameters, wherein the invalid diameters are the diameters with smaller corresponding target correlation values in two adjacent diameters at the middle diameter positions of the multiple diameters to be screened. Therefore, the target diameter adopted in the subsequent cell searching process can be ensured to be an independent effective diameter as much as possible, repeated attempts on the ineffective diameter are avoided, and the cell searching efficiency is improved.

Description

Multipath searcher, cell search device and cell search method

Technical Field

The present disclosure relates to the field of mobile communications technologies, and in particular, to a multipath searcher, a cell search device, and a cell search method.

Background

In recent years, in the field of mobile communication, a Wideband Code Division Multiple Access (WCDMA) mobile communication system has been adopted as one of three international standards for 3 rd generation mobile communication systems. In WCDMA systems, a user terminal device needs to find a network and initiate registration in order to obtain network services. The process of the user terminal device finding the network is called cell search. In the cell search, physical information such as a frequency point, a scrambling code number and the like of a corresponding cell needs to be found, and whether the cell is available or not is judged by decoding broadcast information of the cell.

The cell search generally includes steps of Primary Synchronization Code (PSC) correlation, path search, Secondary Synchronization Code (SSC) correlation, frame header search and scrambling Code group identification, and scrambling Code number identification.

Disclosure of Invention

In order to overcome the problems in the related art, the present disclosure provides a multipath searcher, a cell search apparatus, and a cell search method.

In order to achieve the above object, according to a first aspect of embodiments of the present disclosure, there is provided a multipath searcher comprising:

the path searching module is connected with the PSC correlator and used for determining a plurality of paths to be screened according to a plurality of target correlation values obtained from the PSC correlator;

and the diameter screening module is connected with the diameter searching module and used for eliminating invalid diameters from the multiple diameters to be screened to obtain multiple target diameters, wherein the invalid diameters are the diameters with smaller corresponding target correlation values in two adjacent diameters at the middle diameter positions of the multiple diameters to be screened.

Optionally, the diameter screening module includes:

the bubbling diameter determining submodule is used for determining the diameter with the largest corresponding target correlation value from the diameters which are not marked in the multiple paths to be screened by adopting a bubbling sorting method to obtain a bubbling diameter and marking the bubbling diameter, wherein the multiple paths to be screened are not marked before bubbling sorting;

the elimination submodule is used for eliminating the diameter adjacent to the radial position of the bubbling diameter from the unmarked diameters in the plurality of diameters to be screened;

and the first triggering sub-module is used for triggering the bubbling diameter determining sub-module to determine the diameter with the largest corresponding target correlation value from the unmarked diameters in the multiple paths to be screened by adopting a bubbling sorting method to obtain the bubbling diameter, and marking the bubbling diameter until the number of the unmarked diameters in the multiple paths to be screened is zero to obtain multiple target diameters.

According to a second aspect of the embodiments of the present disclosure, there is provided a cell search apparatus including a PSC correlator, a SSC correlator, a scrambling code group identification unit, and a scrambling code number identification unit, the cell search apparatus further including:

a multipath searcher, an input terminal of which is connected to the PSC correlator and an output terminal of which is connected to the SSC correlator, wherein the multipath searcher is the multipath searcher provided in the first aspect of the disclosure;

the PSC correlator is used for determining a target correlation value of each target sampling point in a received signal;

the SSC correlator is used for correlating the receiving signal with an SSC sequence and carrying out Hadamard transformation on the correlation result to obtain a Hadamard transformed value aiming at each target path in a plurality of target paths obtained from the multipath searcher;

the scrambling code group identification unit is connected with the SSC correlator at the input end and the scrambling code group identification unit at the output end, and is used for determining the frame header position and the scrambling code group number corresponding to the target path according to the Hadamard transformed value;

and the code scrambling number identification unit is used for determining a target code scrambling number according to the received signal and the code scrambling group number corresponding to each target path in the plurality of target paths.

Optionally, the cell search apparatus further includes a shared storage unit;

the PSC correlator is connected with the shared storage unit and is also used for storing the received signal to the shared storage unit;

the SSC correlator is connected with the shared storage unit and is used for acquiring the received signal from the shared storage unit;

the scrambling code number identification unit is connected with the shared storage unit and is used for acquiring the received signal from the shared storage unit.

Optionally, the scrambling code group identifying unit includes:

a correlation frame determination sub-module, connected to the SSC correlator, for determining a correlation frame of the target path through coherent detection according to the hadamard transformed value;

and the frame header searching and scrambling code group identifying sub-module is connected with the related frame determining sub-module and is used for determining the frame header position and the scrambling code group number corresponding to the target path according to the related frame of the target path.

Optionally, the PSC correlator comprises:

PSC correlation RAM, accumulator, sixteen-order filter and temporary RAM;

the output end of the sixteen-order filter is connected with the temporary RAM, and the sixteen-order filter is used for parallelly calculating 16 sliding correlation values of each time aiming at each target sampling point in a received signal and writing the 16 sliding correlation values into the temporary RAM;

and the accumulator has an input end connected with the temporary RAM and an output end connected with the PSC correlation RAM, and is used for reading the sliding correlation values of 16 points in the temporary RAM each time for summation to obtain 16 intermediate values, determining the sum of the 16 intermediate values as a target correlation value of the target sampling point, and outputting the target correlation value to the PSC correlation RAM.

Optionally, the scrambling code number identifying unit includes:

an energy value calculation operator module, configured to determine, according to the received signal, a scrambling code group number corresponding to a target path with a largest corresponding target correlation value among the multiple target paths as a target scrambling code group number, and calculate a correlation energy value of each scrambling code in a scrambling code group corresponding to the target scrambling code group number;

the target scrambling code number determining submodule is used for determining that the cell identification is successful when the ratio of the maximum value in the correlation energy values to the minimum value in the correlation energy values is larger than or equal to a preset multiple threshold value, and determining the scrambling code number corresponding to the maximum value as the target scrambling code number;

a deleting submodule, configured to determine that cell identification fails when a ratio between a maximum value of the plurality of correlation energy values and a minimum value of the plurality of correlation energy values is smaller than the preset multiple threshold, and delete the target path having the largest corresponding target correlation value from the plurality of target paths;

and the second triggering submodule is used for triggering the energy value calculating submodule to determine the scrambling code group number corresponding to the target path with the maximum corresponding target correlation value in the plurality of target paths as a target scrambling code group number according to the received signal, and calculating the correlation energy value of each scrambling code in the scrambling code group corresponding to the target scrambling code group number until the number of the plurality of target paths is zero.

According to a third aspect of the embodiments of the present disclosure, there is provided a cell search method, including:

determining a target correlation value of each target sampling point in a received signal;

determining a plurality of paths to be screened according to the plurality of target correlation values;

removing invalid diameters from the multiple diameters to be screened to obtain multiple target diameters, wherein the invalid diameters are the diameters with smaller corresponding target correlation values in two adjacent diameters at the middle diameter positions of the multiple diameters to be screened;

for each target path in the plurality of target paths, correlating the received signal with an SSC sequence, and performing Hadamard transform to obtain a Hadamard-transformed value;

determining a frame header position and a scrambling code group number corresponding to the target path according to the Hadamard transformed value;

and determining a target scrambling code number according to the received signal and the scrambling code group number sum corresponding to each target path in the plurality of target paths.

Optionally, the determining a plurality of target paths according to the plurality of target correlation values includes:

determining a plurality of paths to be screened according to the plurality of target correlation values;

and eliminating invalid diameters from the multiple diameters to be screened to obtain multiple target diameters, wherein the invalid diameters are the diameters with smaller corresponding target correlation values in two adjacent diameters at the diameter positions in the multiple diameters to be screened.

Optionally, the removing the invalid path from the plurality of paths to be screened to obtain a plurality of target paths includes:

determining a path with the largest corresponding target correlation value from the paths to be screened and the paths which are not marked by adopting a bubbling sorting method to obtain a bubbling path, and marking the bubbling path, wherein the paths to be screened are not marked before the bubbling sorting;

removing the diameters adjacent to the radial positions of the bubbling diameters from the unmarked diameters in the multiple diameters to be screened;

and returning to the step of determining the path with the largest corresponding target correlation value from the paths to be screened and the paths which are not marked by adopting the bubbling sorting method to obtain the bubbling paths and marking the bubbling paths until the number of the paths which are not marked in the paths to be screened is zero, and obtaining a plurality of target paths.

Optionally, the determining, according to the value after the hadamard transform, a frame header position and a scrambling code group number corresponding to the target path includes:

determining a relevant frame of the target path through coherent detection according to the value after the Hadamard transform;

and determining a frame header position and a scrambling code group number corresponding to the target path according to the relevant frame of the target path.

Optionally, the determining a target correlation value of each target sample point in the received signal includes:

for each target sampling point in the received signal, parallel computing 16 points of sliding correlation values each time;

and reading the sliding correlation values of 16 points each time, summing to obtain 16 intermediate values, and determining the sum of the 16 intermediate values as the target correlation value of the target sampling point.

Optionally, the determining a target scrambling code number according to the received signal and the scrambling code group number corresponding to each of the plurality of target paths includes:

according to the received signals, determining a scrambling code group number corresponding to a target path with the maximum corresponding target correlation value in the multiple target paths as a target scrambling code group number, and calculating the correlation energy value of each scrambling code in a scrambling code group corresponding to the target scrambling code group number;

when the ratio of the maximum value in the correlation energy values to the minimum value in the correlation energy values is larger than or equal to a preset multiple threshold value, determining that the cell identification is successful, and determining the scrambling code number corresponding to the maximum value as a target scrambling code number;

when the ratio of the maximum value in the plurality of correlation energy values to the minimum value in the plurality of correlation energy values is smaller than the preset multiple threshold value, determining that cell identification fails, and deleting the target path with the maximum corresponding target correlation value from the plurality of target paths;

and returning to the step of determining the scrambling code group number corresponding to the target path with the maximum corresponding target correlation value in the plurality of target paths as the target scrambling code group number according to the received signal, and calculating the correlation energy value of each scrambling code in the scrambling code group corresponding to the target scrambling code group number until the number of the plurality of target paths is zero.

In the above technical solution, the multipath searcher in the cell search device includes a path search module and a path screening module, wherein the path screening module removes an invalid path from a plurality of paths to be screened after the path search module determines the plurality of paths to be screened, so as to obtain a plurality of target paths. Therefore, the target diameter adopted in the subsequent cell searching process can be ensured to be an independent effective diameter as much as possible, repeated attempts on the ineffective diameter are avoided, and the cell searching efficiency is improved.

Additional features and advantages of the disclosure will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure without limiting the disclosure. In the drawings:

fig. 1 is a block diagram illustrating a cell search apparatus according to an example embodiment.

FIG. 2 illustrates a block diagram of a PSC correlator, according to another exemplary embodiment.

FIG. 3 is a schematic diagram illustrating a process of calculating a target correlation value according to an exemplary embodiment.

Fig. 4 is a block diagram illustrating a cell search apparatus according to another exemplary embodiment.

Fig. 5 is a block diagram illustrating a cell search apparatus according to another exemplary embodiment.

Fig. 6 is a block diagram illustrating a cell search apparatus according to another exemplary embodiment.

Fig. 7 is a block diagram illustrating a cell search apparatus according to another exemplary embodiment.

Fig. 8 is a flow chart illustrating a method of cell search according to an example embodiment.

FIG. 9 is a flow diagram illustrating a method of path screening in accordance with an exemplary embodiment.

Fig. 10 is a flowchart illustrating a method for determining a frame header position and a scrambling code group number corresponding to a target path according to an exemplary embodiment.

FIG. 11 is a flow chart illustrating a method of determining a target correlation value in accordance with an exemplary embodiment.

Fig. 12 is a flow chart illustrating a method of determining a target scrambling code number in accordance with an example embodiment.

Detailed Description

The following detailed description of specific embodiments of the present disclosure is provided in connection with the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present disclosure, are given by way of illustration and explanation only, not limitation.

Fig. 1 is a block diagram illustrating a cell search apparatus according to an example embodiment. Referring to fig. 1, the cell search apparatus may include: PSC correlator 1, SSC correlator 2, multipath searcher 3, scrambling code group identification unit 4, and scrambling code number identification unit 5.

Specifically, PSC correlator 1 may be used to determine a target correlation value for each target sample in a received signal.

In one embodiment, the PSC correlator 1 may include a PSC correlation RAM, an accumulator, and a two hundred fifty-six order filter. Wherein, the output end of the two-hundred fifty-six order filter is connected with the input end of the accumulator, and the accumulator can be used for calculating the sliding correlation value of 256 points aiming at each target sampling point in the received signal; the output of the accumulator is connected to the PSC correlation RAM, which can be used to determine the sum of the 256 point sliding correlations calculated by the two hundred fifty-six order filter as the target correlation for the target sample and output the target correlation to the PSC correlation RAM.

In the above embodiment, since the PSC correlator 1 performs sliding correlation calculation through a two-hundred fifty-six order filter, it needs to occupy a large storage space, and wastes system resources. To this end, in another embodiment, as shown in fig. 2, the above-described PSC correlator 1 may include a PSC correlation RAM11, an accumulator 12, a hexadecimal filter 13, and a temporary RAM 14.

The sixteenth order filter 13 is connected to the temporary RAM14, and is configured to calculate 16 point sliding correlation values in parallel at a time for each target sample in the received signal, and write the 16 point sliding correlation values into the temporary RAM 14. The storage capacity of the temporary RAM14 may store 256 sliding correlation values, that is, the storage capacity of the temporary RAM14 is greater than or equal to the size of the 256 sliding correlation values, and for example, the storage capacity of the temporary RAM14 is 256 bits.

The accumulator 12, which is connected to the temporary RAM14 at one end and the PSC correlation RAM11 at the other end, is configured to sum up sliding correlation values of 16 points at a time read from the temporary RAM14 to obtain 16 intermediate values, determine the sum of the 16 intermediate values as a target correlation value of a target sample, and output the target correlation value to the PSC correlation RAM 11.

The received signal may include 2560 odd samples and 2560 even samples, so that for each odd sample and each even sample, 16 sliding correlation values of the 16 points may be calculated in parallel at a time by the sixteenth order filter 13, and the 16 sliding correlation values may be written into the temporary RAM 14; thereafter, as shown in fig. 3, the accumulator 12 reads 16 points of sliding correlation values at a time from the temporary RAM14, sums them to obtain 16 intermediate values, determines the sum of the 16 intermediate values as a target correlation value of the target sample point, and outputs it to the PSC correlation RAM 11.

Since the sixteenth order filter 13 can calculate 16 point sliding correlation values at a time in parallel for each target sample in the received signal and write the 16 point sliding correlation values into the temporary RAM14, the accumulator 12 can read 16 point sliding correlation values at a time from the temporary RAM14 and sum them to obtain a target correlation value of the target sample. It can be seen that PSC correlator 1 omits the original two hundred fifty-six order filter and uses sixteen order filter 13 and temporary RAM14, thereby saving memory space and optimizing timing sequence, and achieving the effect of saving system resources. In addition, the cell search device provided by the disclosure has simple software and hardware interfaces, avoids frequent interaction between the software and the hardware, and has high efficiency of the WCDMA system.

Returning to fig. 1, a multipath searcher 3, having an input connected to the PSC correlator 1 and an output connected to the SSC correlator 2, can be used to determine a plurality of target paths based on a plurality of target correlation values obtained from the PSC correlator 1.

In this disclosure, in an embodiment, after obtaining a plurality of target correlation values from the PSC correlator 1, the multipath searcher 3 may first sort the target correlation values of each of the 2560 odd-sample points in descending order, and determine the sequence numbers of the odd-sample points corresponding to the 16 target correlation values that are ranked first as the path positions of the paths to be filtered, that is, obtain 16 paths to be filtered. Meanwhile, 16 paths to be screened can be determined in the same manner according to the target correlation value of each sampling point in the 2560 even sampling points, namely, 32 paths to be screened are obtained in total. And then, directly determining the 32 paths to be screened as target paths, namely obtaining the 32 target paths.

In another embodiment, after acquiring a plurality of target correlation values from the PSC correlator 1, the multipath searcher 3 may use a bubble sorting method to screen 16 target correlation values from the target correlation values of each of 2560 odd-sample points, wherein each bubble screens a maximum value from the remaining target correlation values, and then determines the serial numbers of the odd-sample points corresponding to the 16 target correlation values as the path positions of the paths to be screened, that is, to obtain 16 paths to be screened. Meanwhile, 16 paths to be screened can be determined in the same manner according to the target correlation value of each sampling point in the 2560 even sampling points, namely, 32 paths to be screened are obtained in total. And then, directly determining the 32 paths to be screened as target paths, namely obtaining the 32 target paths.

However, the side lobe position of the main path may also have a higher peak value, and the odd-even path may also have a peak value adjacent to each other to a great extent, that is, an invalid path may exist in the determined 32 paths to be screened, so that the invalid path can be eliminated after the plurality of paths to be screened are determined, and thus, the target path adopted in the subsequent cell search process can be ensured to be an independent effective path as much as possible, repeated attempts on the invalid path are avoided, and the cell search efficiency is improved. Specifically, as shown in fig. 1, the multipath searcher 3 may include: a path search module 31 and a path filtering module 32.

The path searching module 31 is connected to the PSC correlator 1, and configured to determine a plurality of paths to be filtered according to a plurality of target correlation values obtained from the PSC correlator 1. The specific manner of determining the plurality of paths to be filtered by the path searching module 31 is as described above, and is not described herein again.

The diameter screening module 32 is connected to the diameter searching module 31, and is configured to remove an invalid diameter from the multiple diameters to be screened to obtain multiple target diameters, where the invalid diameter may be a diameter with a smaller target correlation value in two adjacent diameters at the middle diameter position of the multiple diameters to be screened.

For example, the plurality of target diameters include two target diameters having respective diameter positions 152 and 153, and if the target correlation value corresponding to the target diameter having the diameter position 152 is smaller than the target correlation value corresponding to the target diameter having the diameter position 153, the target diameter having the diameter position 152 is an invalid diameter, and therefore, the target diameter having the diameter position 152 can be excluded from the plurality of target diameters.

In an embodiment, the diameter screening module 32 may respectively search, for each to-be-screened diameter of the to-be-screened diameters, whether a diameter adjacent to the diameter position of the to-be-screened diameter exists in the to-be-screened diameters, and when there is a diameter adjacent to the diameter position of the to-be-screened diameter and a target correlation value corresponding to the diameter adjacent to the diameter position of the to-be-screened diameter is smaller than a target correlation value corresponding to the to-be-screened diameter, reject the diameter adjacent to the diameter position of the to-be-screened diameter, otherwise reject the to-be-screened diameter.

In another embodiment, in order to improve the efficiency of the path screening, the path screening can be performed by combining the principle of bubble sorting method. As shown in fig. 4, the diameter screening module 32 may include a bubbling diameter determining sub-module 321, a culling sub-module 322, and a first triggering sub-module 323.

Specifically, the bubbling path determining submodule 321 may be configured to determine, by using a bubbling sorting method, a path with the largest corresponding target correlation value from among the paths to be screened and the unmarked paths, obtain a bubbling path, and mark the bubbling path.

And the eliminating submodule 322 is used for eliminating the diameter adjacent to the position of the bubbling diameter from the unmarked diameters and the diameters in the plurality of diameters to be screened.

The first triggering sub-module 323 is configured to trigger the bubbling path determining sub-module 321 to determine, by using a bubbling sorting method, a path with a largest corresponding target correlation value from among the multiple paths to be screened and the unmarked paths, to obtain a bubbling path, and mark the bubbling path until the number of unmarked paths in the multiple paths to be screened is zero, to obtain multiple target paths.

In the present disclosure, before performing bubble sorting, none of the paths to be screened obtained by the path search module 31 is marked. Because the bubbling diameter is the diameter with the maximum target correlation value corresponding to the unmarked diameter in the multiple diameters to be screened, after the bubbling diameter is obtained, if the diameter adjacent to the diameter position of the bubbling diameter exists in the unmarked diameters in the multiple diameters to be screened, the diameter adjacent to the diameter position of the bubbling diameter can be directly eliminated, and the target correlation value corresponding to the diameter adjacent to the diameter position of the bubbling diameter does not need to be compared with the target correlation value corresponding to the bubbling diameter, so that the efficiency of diameter screening is improved.

After obtaining the bubbling diameter, if the diameter adjacent to the position of the bubbling diameter does not exist in the multiple diameters to be screened and the unmarked diameters, or the diameters adjacent to the position of the bubbling diameter are eliminated, the step of obtaining the bubbling diameter and marking the bubbling diameter by adopting a bubbling sorting method to obtain the diameter with the largest corresponding target correlation value from the multiple diameters to be screened and the unmarked diameters can be executed again until the number of the unmarked diameters in the multiple diameters to be screened is zero, so that the multiple target diameters can be obtained.

Returning to fig. 1, the SSC correlator 2 may be configured to correlate the received signal with the SSC sequence for each of a plurality of target paths obtained by the multipath searcher 3, and perform hadamard (hadamard) transform to obtain a hadamard-transformed value.

In the present disclosure, the calculation of the SSC correlator 2 can adopt a sliding correlator, the path position other than the target path discards the PSC calculation, and only the path position corresponding to the target path reads the corresponding target correlation value, so as to perform hadnard identification on the despread Z sequence. The 1 sample hadnard transform requires 21 clock cycles (cycles), so the cycle overhead of one slot is 2560 x the number of target paths (21-1). Illustratively, the cycles required for 16 target paths of 1 slot is only 2880 cycles; whereas the conventional calculation of the SSC correlator 2 requires 256 samples at each sample point to be read, the 16-path SSC calculation for one slot requires at least (256+16) × 16 ═ 4352 cycles. Obviously, when the number of slots is large, the cycle overhead difference is larger.

As shown in fig. 1, the scrambling code group identification unit 4 has an input terminal connected to the SSC correlator 2 and an output terminal connected to the scrambling code group identification unit 5, and is configured to determine a frame header position and a scrambling code group number corresponding to the target path according to the hadamard-transformed value obtained by the SSC correlator 2.

In one embodiment, the scrambling code group identification unit 4 may directly make a correlation value determination according to the hadamard transformed value obtained by the SSC correlator 2, so as to obtain a 16 × 15 correlation frame of the target path; and then, aiming at each target path in the plurality of paths, determining a frame header position and a scrambling code group number corresponding to the target path according to the relevant frame of the target path. Specifically, after the relevant frame of each target path is obtained, the corresponding offset and the pattern number may be found in a manner of matching with the local 64 patterns, and then the corresponding offset is determined as the frame header position corresponding to the target path, and the pattern number is determined as the scrambling code group number corresponding to the target path.

The specific manner of obtaining the relevant frame of the target path through the correlation value determination and the specific manner of matching are well known to those skilled in the art, and are not described herein again.

In another embodiment, as shown in fig. 5, the scrambling code group identification unit 4 may include a related frame determination sub-module 41 and a frame header searching and scrambling code group identification sub-module 42.

Specifically, the correlation frame determination sub-module 41 may be connected to the SSC correlator 2, and may be configured to determine, for each of the plurality of target paths obtained by the multipath searcher 3, a correlation frame of the target path by coherent detection based on the hadamard-transformed value obtained by the SSC correlator 2.

After Hadmard conversion, the correlation value judgment is not directly carried out, but coherent detection is adopted, namely, the Hadmard converted value is multiplied by the target correlation value corresponding to the target path, the real part and the correlation value of the previous frame are accumulated and written into a cache, and finally a correlation frame with the size of 16 x 15 of the target path can be obtained.

And a frame header searching and scrambling code group identifying sub-module 42, connected to the related frame determining sub-module 41, for determining, for each target path of the multiple paths, a frame header position and a scrambling code group number corresponding to the target path according to the related frame of the target path.

In this disclosure, after the related frame determining sub-module 41 obtains the related frame of each target path, the frame header position and the scrambling code group number corresponding to the target path may be determined in the manner described in the above embodiment, which is not described herein again.

Returning to fig. 1, the scrambling code number identifying unit 5 may be configured to determine a target scrambling code number according to the received signal and the corresponding scrambling code group number and received signal of each of the plurality of target paths.

In one embodiment, the scrambling code number identifying unit 5 may first calculate the correlation energy value of each scrambling code in the scrambling code group corresponding to the scrambling code group number corresponding to each of the plurality of target paths, and then determine the scrambling code number corresponding to the maximum value among the correlation energy values corresponding to all the target paths as the target scrambling code number.

In another embodiment, the larger the target correlation value corresponding to the target path is, the more likely the corresponding cell is to be the target cell to be resided in, so that the scrambling code group number corresponding to the target path with the largest target correlation value among the multiple target paths may be determined as the target scrambling code group number, then the correlation energy value of each scrambling code in the scrambling code group corresponding to the target scrambling code group number is calculated, then whether cell identification is successful is determined according to the multiple correlation energy values, if successful, the scrambling code number corresponding to the largest value among the multiple correlation energy values is determined as the target scrambling code number, that is, the cell number, and reporting is performed without calculating the correlation energy value of each scrambling code in the scrambling code group corresponding to the scrambling code group numbers corresponding to all the target paths, and thus, the efficiency of cell search may be improved.

Specifically, as shown in fig. 6, the scrambling code number identifying unit 5 may include an energy value calculating sub-module 51, a target scrambling code number determining sub-module 52, a deleting sub-module 53, and a second triggering sub-module 54.

The energy value calculating operator module 51 may be configured to determine, according to the received signal, a scrambling code group number corresponding to a target path with a largest target correlation value among the multiple target paths as a target scrambling code group number, and calculate a correlation energy value of each scrambling code in a scrambling code group corresponding to the target scrambling code group number.

The target scrambling code number determining submodule 52 may be configured to determine that the cell identification is successful when a ratio between a maximum value of the plurality of correlation energy values and a minimum value of the plurality of correlation energy values is greater than or equal to a preset multiple threshold, and determine a scrambling code number corresponding to the maximum value of the correlation energy values as a target scrambling code number.

The deleting submodule 53 may be configured to determine that cell identification fails when a ratio between a maximum value of the plurality of correlation energy values and a minimum value of the plurality of correlation energy values is smaller than the preset multiple threshold, and delete the target path with the largest corresponding target correlation value from the plurality of target paths.

The second triggering sub-module 54 may be configured to trigger the energy value calculating sub-module 51 to determine, according to the received signal, the scrambling code group number corresponding to the target path with the largest target correlation value among the multiple target paths as a target scrambling code group number, and calculate the correlation energy value of each scrambling code in the scrambling code group corresponding to the target scrambling code group number until the number of the multiple target paths is zero.

In this disclosure, the scrambling code group number corresponding to the target path with the largest corresponding target correlation value among the multiple target paths may be determined as a target scrambling code group number, and the correlation energy value of each scrambling code in the scrambling code group corresponding to the target scrambling code group number is calculated; and then, judging whether the ratio of the maximum value in the plurality of correlation energy values to the minimum value in the plurality of correlation energy values is larger than or equal to a preset multiple threshold value or not. If so, determining that the cell identification is successful, determining the scrambling code number corresponding to the maximum value in the correlation energy values as a target scrambling code number, namely reporting the target scrambling code number as a target cell number, and finishing the cell search at this moment. If not, determining that the cell identification fails, deleting the target path with the maximum corresponding target correlation value from the target paths, then returning to the step of determining the scrambling code group number corresponding to the target path with the maximum corresponding target correlation value from the target paths as the target scrambling code group number, and calculating the correlation energy value of each scrambling code in the scrambling code group corresponding to the target scrambling code group number until the number of the target paths is zero. If the number of the target paths is zero, the determined target paths are all false paths, and at this time, the cell search operation can be performed again.

The preset multiple threshold may be a value set by a user, or may be a default value (for example, the preset multiple threshold is 3), and is not particularly limited in this disclosure.

In the above technical solution, the multipath searcher in the cell search device includes a path search module and a path screening module, wherein the path screening module removes an invalid path from a plurality of paths to be screened after the path search module determines the plurality of paths to be screened, so as to obtain a plurality of target paths. Therefore, the target diameter adopted in the subsequent cell searching process can be ensured to be an independent effective diameter as much as possible, repeated attempts on the ineffective diameter are avoided, and the cell searching efficiency is improved.

In addition, if the SSC correlator 2 and the scrambling code number identification unit 5 in the cell search device need to acquire a received signal from the antenna end when the received signal is needed, the time consumption is high, and therefore, the shared storage unit can be used for caching the received signal, so that the SSC correlator 2 and the scrambling code number identification unit 5 can directly acquire the received signal from the shared storage unit, the operation is convenient and fast, the time delay is reduced, and the cell search efficiency is improved. Specifically, as shown in fig. 7, the cell search apparatus may further include a shared storage unit 6. The PSC correlator 1 is connected to the shared memory unit 6, and can be used to store the received signal in the shared memory unit 6. In addition, the SSC correlator 2 and the scrambling code number identification unit 5 are both connected with the shared storage unit 6, so that the SSC correlator 2 and the scrambling code number identification unit can directly acquire received signals from the shared storage unit 6, convenience and rapidness are achieved, and the cell search efficiency is improved.

The shared storage unit 6 may be an additional storage module, or may be an existing storage module (e.g., a memory unit) in the cell search apparatus. Moreover, the shared storage unit 6 is preferably an existing storage module of the cell search device, so that no additional storage module is needed, thereby reducing the cost of the cell search device and saving time and labor.

Fig. 8 is a flow chart illustrating a method of cell search according to an example embodiment. Referring to fig. 8, the method may include the following steps 801 to 806.

In step 801, a target correlation value for each target sample in the received signal is determined.

In step 802, a plurality of paths to be screened are determined according to the plurality of target correlation values.

In step 803, an invalid path is removed from the plurality of paths to be screened, and a plurality of target paths are obtained.

In step 804, for each of the plurality of target paths, the received signal is correlated with the SSC sequence and hadamard transformed to obtain a hadamard transformed value.

In step 805, according to the hadamard transformed value, determining a frame header position and a scrambling code group number corresponding to the target path;

in step 806, a target scrambling code number is determined according to the received signal and the scrambling code number corresponding to each of the plurality of target paths.

FIG. 9 is a flow chart illustrating a method of path screening in accordance with an exemplary embodiment. Referring to fig. 9, the step 803 may include the following steps 8031 to 8033.

In step 8031, a bubbling sorting method is used to determine a path with the largest corresponding target correlation value from among the paths to be screened and the unmarked paths, so as to obtain a bubbling path, and mark the bubbling path.

In step 8032, the diameter adjacent to the position of the bubbling diameter is removed from the unmarked diameters of the plurality of diameters to be screened.

In step 8033, it is determined whether the number of unmarked paths among the plurality of paths to be screened is zero.

In the present disclosure, if the number of unmarked paths in the plurality of paths to be screened is not zero, the process returns to step 8031 to continue to be executed until the number of unmarked paths in the plurality of paths to be screened is not zero, at which time, a plurality of target paths may be obtained, and then the step 804 is executed.

Fig. 10 is a flowchart illustrating a method for determining a frame header position and a scrambling code group number corresponding to a target path according to an exemplary embodiment. Referring to fig. 10, the above step 805 may include the following step 8051 and step 8052.

In step 8051, a correlation frame of the target path is determined by coherent detection according to the hadamard transformed value.

In step 8052, according to the relevant frame of the target path, the frame header position and the scrambling code group number corresponding to the target path are determined.

FIG. 11 is a flow chart illustrating a method of determining a target correlation value in accordance with an exemplary embodiment. Referring to fig. 11, the above step 801 may include the following steps 8011 and 8012.

In step 8011, 16 sliding correlation values are computed in parallel for each target sample in the received signal at a time.

In step 8012, 16 sliding correlation values are read and summed at a time to obtain 16 intermediate values, and the sum of the 16 intermediate values is determined as the target correlation value of the target sampling point.

Fig. 12 is a flow chart illustrating a method of determining a target scrambling code number in accordance with an example embodiment. Referring to fig. 12, the step 806 may include the following steps 8061 to 8065.

In step 8061, according to the received signal, the scrambling code group number corresponding to the target path with the largest target correlation value among the plurality of target paths is determined as the target scrambling code group number, and the correlation energy value of each scrambling code in the scrambling code group corresponding to the target scrambling code group number is calculated.

In step 8062, it is determined whether a ratio between a maximum value of the correlation energy values and a minimum value of the correlation energy values is greater than or equal to a preset multiple threshold.

In the present disclosure, if a ratio between a maximum value of the plurality of correlation energy values and a minimum value of the plurality of correlation energy values is greater than or equal to a preset multiple threshold, the following step 8063 is performed, otherwise, the following step 8064 is performed.

In step 8063, it is determined that the cell identification is successful, and the scrambling code number corresponding to the maximum value of the plurality of correlation energy values is determined as the target scrambling code number.

In step 8064, it is determined that the cell identification has failed, and the target path having the largest corresponding target correlation value is deleted from the multiple entry paths.

In step 8065, it is determined whether the number of target paths is zero.

In the present disclosure, if the number of the plurality of target paths is not zero, the step 8061 is returned to, otherwise, the process is ended.

With regard to the method in the above-mentioned embodiment, the specific manner in which each step performs operations has been described in detail in the embodiment related to the cell search apparatus, and will not be elaborated here.

The preferred embodiments of the present disclosure are described in detail with reference to the accompanying drawings, however, the present disclosure is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present disclosure within the technical idea of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.

It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. In order to avoid unnecessary repetition, various possible combinations will not be separately described in this disclosure.

In addition, any combination of various embodiments of the present disclosure may be made, and the same should be considered as the disclosure of the present disclosure, as long as it does not depart from the spirit of the present disclosure.

Claims (7)

1. A cell search apparatus comprising a PSC correlator, a SSC correlator, a scrambling code group identification unit, a scrambling code number identification unit, the cell search apparatus further comprising:

a multipath searcher having an input coupled to said PSC correlator and an output coupled to said SSC correlator;

the PSC correlator is used for determining a target correlation value of each target sampling point in a received signal;

the SSC correlator is used for correlating the receiving signal with an SSC sequence and carrying out Hadamard transformation on the correlation result to obtain a Hadamard transformed value aiming at each target path in a plurality of target paths obtained from the multipath searcher;

the scrambling code group identification unit is connected with the SSC correlator at the input end and the scrambling code group identification unit at the output end, and is used for determining the frame header position and the scrambling code group number corresponding to the target path according to the Hadamard transformed value;

the scrambling code number identification unit is used for determining a target scrambling code number according to the received signal and the scrambling code group number corresponding to each target path in the plurality of target paths;

wherein the multipath searcher comprises:

the path searching module is connected with the PSC correlator and used for determining a plurality of paths to be screened according to a plurality of target correlation values obtained from the PSC correlator;

the path screening module is connected with the path searching module and used for eliminating invalid paths from the paths to be screened to obtain a plurality of target paths, wherein the invalid paths are the paths with smaller corresponding target correlation values in two paths adjacent to the path middle positions of the paths to be screened;

the diameter screening module comprises:

the bubbling diameter determining submodule is used for determining the diameter with the largest corresponding target correlation value from the diameters which are not marked in the multiple paths to be screened by adopting a bubbling sorting method to obtain a bubbling diameter and marking the bubbling diameter, wherein the multiple paths to be screened are not marked before bubbling sorting;

the elimination submodule is used for eliminating the diameter adjacent to the radial position of the bubbling diameter from the unmarked diameters in the plurality of diameters to be screened;

the PSC correlator includes:

PSC correlation RAM, accumulator, sixteen-order filter and temporary RAM;

the output end of the sixteen-order filter is connected with the temporary RAM, and the sixteen-order filter is used for parallelly calculating 16 sliding correlation values of each time aiming at each target sampling point in a received signal and writing the 16 sliding correlation values into the temporary RAM;

and the accumulator has an input end connected with the temporary RAM and an output end connected with the PSC correlation RAM, and is used for reading the sliding correlation values of 16 points in the temporary RAM each time for summation to obtain 16 intermediate values, determining the sum of the 16 intermediate values as a target correlation value of the target sampling point, and outputting the target correlation value to the PSC correlation RAM.

2. The cell search apparatus according to claim 1, wherein the cell search apparatus further comprises a shared storage unit;

the PSC correlator is connected with the shared storage unit and is also used for storing the received signal to the shared storage unit;

the SSC correlator is connected with the shared storage unit and is used for acquiring the received signal from the shared storage unit;

the scrambling code number identification unit is connected with the shared storage unit and is used for acquiring the received signal from the shared storage unit.

3. The cell search apparatus of claim 1 or 2, wherein the scrambling code group identification unit comprises:

a correlation frame determination sub-module, connected to the SSC correlator, for determining a correlation frame of the target path through coherent detection according to the hadamard transformed value;

and the frame header searching and scrambling code group identifying sub-module is connected with the related frame determining sub-module and is used for determining the frame header position and the scrambling code group number corresponding to the target path according to the related frame of the target path.

4. The cell search device according to claim 1 or 2, wherein the scrambling code number identifying unit includes:

an energy value calculation operator module, configured to determine, according to the received signal, a scrambling code group number corresponding to a target path with a largest corresponding target correlation value among the multiple target paths as a target scrambling code group number, and calculate a correlation energy value of each scrambling code in a scrambling code group corresponding to the target scrambling code group number;

the target scrambling code number determining submodule is used for determining that the cell identification is successful when the ratio of the maximum value in the correlation energy values to the minimum value in the correlation energy values is larger than or equal to a preset multiple threshold value, and determining the scrambling code number corresponding to the maximum value as the target scrambling code number;

a deleting submodule, configured to determine that cell identification fails when a ratio between a maximum value of the plurality of correlation energy values and a minimum value of the plurality of correlation energy values is smaller than the preset multiple threshold, and delete the target path having the largest corresponding target correlation value from the plurality of target paths;

and the second triggering submodule is used for triggering the energy value calculating submodule to determine the scrambling code group number corresponding to the target path with the maximum corresponding target correlation value in the plurality of target paths as a target scrambling code group number according to the received signal, and calculating the correlation energy value of each scrambling code in the scrambling code group corresponding to the target scrambling code group number until the number of the plurality of target paths is zero.

5. A method of cell search, comprising:

for each target sampling point in the received signal, parallel computing 16 points of sliding correlation values each time;

reading the sliding correlation values of 16 points each time, summing to obtain 16 intermediate values, and determining the sum of the 16 intermediate values as the target correlation value of the target sampling point;

determining a plurality of paths to be screened according to the plurality of target correlation values;

removing invalid diameters from the multiple diameters to be screened to obtain multiple target diameters, wherein the invalid diameters are the diameters with smaller corresponding target correlation values in two adjacent diameters at the middle diameter positions of the multiple diameters to be screened;

for each target path in the plurality of target paths, correlating the received signal with an SSC sequence, and performing Hadamard transform to obtain a Hadamard-transformed value;

determining a frame header position and a scrambling code group number corresponding to the target path according to the Hadamard transformed value;

determining a target scrambling code number according to the receiving signal and the scrambling code group number and the receiving signal corresponding to each target path in the plurality of target paths;

the step of removing the invalid path from the plurality of paths to be screened to obtain a plurality of target paths comprises the following steps:

determining a path with the largest corresponding target correlation value from the paths to be screened and the paths which are not marked by adopting a bubbling sorting method to obtain a bubbling path, and marking the bubbling path, wherein the paths to be screened are not marked before the bubbling sorting;

removing the diameters adjacent to the radial positions of the bubbling diameters from the unmarked diameters in the multiple diameters to be screened;

and returning to the step of determining the path with the largest corresponding target correlation value from the paths to be screened and the paths which are not marked by adopting the bubbling sorting method to obtain the bubbling paths and marking the bubbling paths until the number of the paths which are not marked in the paths to be screened is zero, and obtaining a plurality of target paths.

6. The method of claim 5, wherein the determining the frame header position and the scrambling code group number corresponding to the target path according to the Hadamard transformed value comprises:

determining a relevant frame of the target path through coherent detection according to the value after the Hadamard transform;

and determining a frame header position and a scrambling code group number corresponding to the target path according to the relevant frame of the target path.

7. The method of claim 5, wherein determining a target scrambling code number based on the received signal and the corresponding scrambling code group number for each of a plurality of target paths comprises:

according to the received signals, determining a scrambling code group number corresponding to a target path with the maximum corresponding target correlation value in the multiple target paths as a target scrambling code group number, and calculating the correlation energy value of each scrambling code in a scrambling code group corresponding to the target scrambling code group number;

when the ratio of the maximum value in the correlation energy values to the minimum value in the correlation energy values is larger than or equal to a preset multiple threshold value, determining that the cell identification is successful, and determining the scrambling code number corresponding to the maximum value as a target scrambling code number;

when the ratio of the maximum value in the plurality of correlation energy values to the minimum value in the plurality of correlation energy values is smaller than the preset multiple threshold value, determining that cell identification fails, and deleting the target path with the maximum corresponding target correlation value from the plurality of target paths;

and returning to the step of determining the scrambling code group number corresponding to the target path with the maximum corresponding target correlation value in the plurality of target paths as the target scrambling code group number according to the received signal, and calculating the correlation energy value of each scrambling code in the scrambling code group corresponding to the target scrambling code group number until the number of the plurality of target paths is zero.

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