CN111294889B - Cell search method and device, storage medium and terminal - Google Patents
Cell search method and device, storage medium and terminal Download PDFInfo
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- H04W48/16—Discovering, processing access restriction or access information
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Abstract
A cell search method and device, a storage medium and a terminal are provided, wherein the cell search method comprises the following steps: determining a current carrier, wherein the current carrier is selected from a frequency point list; at least carrying out coherent detection on the current carrier to obtain a coherent detection result of the current carrier; and when the coherent detection result of the current carrier meets a preset search condition, carrying out cell search and residence on the current carrier. By the technical scheme provided by the invention, a good frequency scanning effect can be obtained even in a low signal-to-noise ratio scene, and the frequency scanning device is easy to reside in a cell with good channel quality.
Description
Technical Field
The present invention relates to the field of communications technologies, and in particular, to a cell search method and apparatus, a storage medium, and a terminal.
Background
Wireless communication systems are typically deployed in different carriers (i.e., center frequency points) for licensed spectrum licensing or network optimization reasons. When a User Equipment (UE) is powered on or enters a new area, the UE may not know in which carrier the operator is deployed. To determine the carriers, the most straightforward approach is to perform a cell search over all possible carriers. However, since the number of carriers may be large (e.g., up to several hundred), it takes a lot of time to complete the search. The UE typically performs a frequency scanning (frequency scanning) operation to determine on which carrier or carriers to perform a cell search.
In the prior art, the frequency scanning process is as follows: the power of each carrier is first detected for a short time, and then the power of all carriers is sorted. Based on the ranking results, the UE determines a carrier on which to perform cell search. On the one hand, however, even if the power is large, it may come from an interfering signal, not a useful signal. On the other hand, in low signal-to-noise ratio environments (e.g., when the signal-to-noise ratio is below-10 dB), the wanted signal may be swamped by noise. That is, the power-based cell search method may not be able to determine the carriers deployed by the operator.
Disclosure of Invention
The invention solves the technical problem of how to optimize cell search so as to obtain good frequency scanning effect in a scene with low signal-to-noise ratio, accelerate the cell search speed and be beneficial to residing in a cell with good channel quality.
To solve the foregoing technical problem, an embodiment of the present invention provides a cell search method, including: determining a current carrier, wherein the current carrier is selected from a frequency point list; at least carrying out coherent detection on the current carrier to obtain a coherent detection result of the current carrier; and when the coherent detection result of the current carrier meets a preset search condition, carrying out cell search and residence on the current carrier.
Optionally, the cell search method further includes: and if the cell search result is that a cell is searched and the cell meets a preset residing condition, attempting to reside in the cell.
Optionally, the fact that the coherent detection result satisfies the preset search condition means: the coherent detection result exceeds a first preset threshold, or the coherent detection result exceeds the first preset threshold and is superior to coherent detection results of two other carriers, wherein the two other carriers are selected from the frequency point list, and the index of the current carrier is between the indexes of the two other carriers.
Optionally, the cell search method further includes: when the coherent detection result of the current carrier does not meet the preset search condition or meets the preset search condition but the cell search resident result fails, performing coherent detection on each other carrier in the frequency point list one by one to obtain the coherent detection result of each other carrier; if the coherent detection results of all other carriers do not meet the preset search condition, or the search of the resident results in other carrier cells meeting the preset search condition fails, sorting the coherent detection results of all carriers in the frequency point list in a descending order to obtain N carriers sorted at the top, wherein N is a positive integer greater than or equal to 1; and when the cell search results obtained by the N carriers sequenced in the front have the cell meeting the preset residence condition, trying to reside in the cell meeting the preset residence condition.
Optionally, the failure of the cell search camping result refers to: the cell search result is that the cell is not searched; or the cell search result is that the cell is searched, but the cell does not meet the preset residence condition; or, the cell search result is that a cell is searched, and the cell meets the preset residence condition, but the attempt to reside results in failure.
Optionally, the cell search method further includes: when the coherent detection result of the current carrier does not meet the preset search condition, or the coherent detection result of the current carrier meets the preset search condition but the cell search is failed to reside, storing the coherent detection result of the current carrier; and when the coherent detection results of the other carriers do not meet the preset search condition, or the coherent detection results of the other carriers meet the preset search condition but the cell search dwell fails, storing the coherent detection results of the other carriers.
Optionally, when there is a cell that satisfies a preset camping condition in the cell search results obtained by the N carriers ranked in the top order, attempting to camp on the cell that satisfies the preset camping condition includes: and for the N carriers which are sequenced at the front, sequentially carrying out cell search on each carrier according to the sequencing sequence, and trying to reside the cell which meets the preset residing condition.
Optionally, the cell search method further includes: and if the cell search dwell fails and reaches the preset maximum frequency scanning times in the process of cell search dwell of the N carriers sequenced at the front, terminating the frequency scanning and the cell search.
Optionally, the performing coherent detection on at least the current carrier to obtain a coherent detection result of the current carrier includes: and carrying out PSS coherent detection on the current carrier, and taking the obtained PSS detection result as the coherent detection result of the current carrier.
Optionally, the performing coherent detection on at least the current carrier to obtain a coherent detection result of the current carrier includes: PSS coherent detection is carried out on the current carrier wave to obtain a first detection result of the current carrier wave; calculating the signal power on the current carrier to obtain a second detection result of the current carrier; and taking the weighted sum of the first detection result and the second detection result as the coherent detection result of the current carrier.
Optionally, the performing coherent detection on at least the current carrier to obtain a coherent detection result of the current carrier includes: PSS coherent detection is carried out on the current carrier wave to obtain a first detection result of the current carrier wave; carrying out incoherent detection on the current carrier to obtain a second detection result of the current carrier; and substituting the first detection result and the second detection result into a preset function relation to calculate, and taking the calculation result as the coherent detection result of the current carrier.
To solve the foregoing technical problem, an embodiment of the present invention further provides a cell search apparatus, including: a determining module adapted to determine a current carrier, the current carrier being selected from a list of frequency points; the first detection module is suitable for carrying out coherent detection on at least the current carrier to obtain a coherent detection result of the current carrier; and the searching module is suitable for carrying out cell searching and residing on the current carrier when the coherent detection result of the current carrier meets the preset searching condition.
To solve the above technical problem, an embodiment of the present invention further provides a storage medium having stored thereon computer instructions, where the computer instructions execute the steps of the above method when executed.
In order to solve the foregoing technical problem, an embodiment of the present invention further provides a terminal, including a memory and a processor, where the memory stores computer instructions executable on the processor, and the processor executes the computer instructions to perform the steps of the foregoing method.
Compared with the prior art, the technical scheme of the embodiment of the invention has the following beneficial effects:
the embodiment of the invention provides a cell search method, which comprises the following steps: determining a current carrier, wherein the current carrier is selected from a frequency point list; at least carrying out coherent detection on the current carrier to obtain a coherent detection result of the current carrier; and when the coherent detection result of the current carrier meets a preset search condition, carrying out cell search and residence on the current carrier. When the frequency scanning is carried out, if the current carrier meeting the preset searching condition is found, the frequency scanning can be interrupted temporarily, the cell searching is carried out on the current carrier, and the cell searching resident speed can be accelerated. Compared with the incoherent detection scheme adopted by the prior art, the coherent detection method is adopted in the embodiment of the invention, and the useful signal cannot be submerged by noise even if the terminal is in a low signal-to-noise ratio environment (for example, when the signal-to-noise ratio is lower than-10 dB), so that the embodiment of the invention is easy to obtain a good frequency scanning effect even in the low signal-to-noise ratio environment and is easy to reside in a cell with good channel quality.
Further, if the cell search result is that a cell is searched and the cell meets a preset residing condition, attempting to reside in the cell. Through the technical scheme provided by the embodiment of the invention, when the cell search result meets the preset residence condition, the cell is attempted to reside, the frequency scanning process is accelerated, the time for residence of the cell is reduced, the power consumption is saved, and a feasible scheme is further provided for accelerating the residence speed of the cell search. Those skilled in the art will understand that even if the cell search camping result fails, the previously interrupted frequency scanning process may be resumed to continue coherent detection on the next carrier after the current carrier (i.e., frequency bin).
Further, the performing coherent detection on at least the current carrier to obtain a coherent detection result of the current carrier includes: and carrying out PSS coherent detection on the current carrier, and taking the obtained PSS detection result as the coherent detection result of the current carrier. The embodiment of the invention carries out blind detection based on the synchronous signal (such as the PSS signal), and the blind detection result can be used as a coherent detection result, so that a good frequency scanning result can be obtained under the condition of low signal-to-noise ratio, and a feasible scheme is further provided for faster residence to a better cell.
Drawings
Fig. 1 is a flowchart illustrating a cell search method according to an embodiment of the present invention;
fig. 2 is a flowchart illustrating a cell search method according to another embodiment of the present invention;
fig. 3 is a schematic structural diagram of a cell search apparatus according to an embodiment of the present invention.
Detailed Description
As background art, in the prior art, a power detection method is used for frequency scanning, and under the condition of a low signal-to-noise ratio, the frequency scanning time is long, the effect is poor, and the frequency scanning is difficult to reside in a suitable cell.
Wireless communication systems may be deployed on different carriers (e.g., carriers of different center frequencies) due to granted spectrum grants or network optimization. When a User Equipment (UE) is powered on or enters a new area, the UE may not know which carrier its operator is deployed on.
One of the most straightforward methods is for the UE to perform cell search on all possible carriers one by one. However, since the number of carriers may be large (up to several hundreds), the entire search may take a long time.
To this end, the UE typically performs a frequency scanning operation to perform cell search after determining a carrier or carriers.
In the prior art, a typical scheme is as follows: the UE performs frequency scanning, typically, detects power (e.g., listening signal strength) of each carrier only for a short time, ranks the power of the respective carriers, and then determines a carrier on which cell search is to be performed based on the ranking result.
Another exemplary scheme is as follows: the UE executes frequency scanning time division into a coarse scanning process and a fine scanning process, wherein the coarse scanning process is to convert time domain received data into a frequency domain through Fast Fourier Transform (FFT), determine the bandwidth and the central frequency point of a system by judging the initial position of a frequency spectrum after the frequency spectrum is shaped, and reduce errors through a certain rule, so that the bandwidth of the system can be determined and the central frequency point can be roughly determined; and the fine scanning is to measure the power of a plurality of frequency points by taking a fixed frequency interval as a step length near the alternative central frequency point determined by the coarse scanning, and after a group of alternative frequency points is obtained, the frequency point corresponding to the maximum power value is selected as the central frequency point for the user to select and access. The scheme still determines the frequency points based on power.
However, in a low Signal-to-Noise ratio (SNR) system, since the SNR may be as low as-10 decibels (dB), the power of the useful Signal may be much lower than the Noise power. At this point, the power-based frequency scanning method is no longer able to distinguish the deployed carriers. Also, the method based on power detection is a non-coherent detection method. Compared with a coherent detection method, a noncoherent detection method has poor performance.
Through careful research, the carrier is usually selected after all frequency points in the frequency point list are scanned in the prior art, and cell search is performed based on the selected carrier. Because the number of the frequency points in the frequency point list can reach hundreds, the cell search is carried out by adopting the prior art scheme, and the time delay is very long.
The embodiment of the invention provides a cell searching method, which comprises the following steps: determining a current carrier, wherein the current carrier is selected from a frequency point list; at least carrying out coherent detection on the current carrier to obtain a coherent detection result of the current carrier; and when the coherent detection result of the current carrier meets a preset search condition, carrying out cell search and residence on the current carrier.
When the frequency scanning is carried out, if the current carrier meeting the preset searching condition is found, the frequency scanning can be interrupted temporarily, the cell searching is carried out on the current carrier, and the cell searching resident speed can be accelerated. Compared with the incoherent detection scheme adopted by the prior art, the coherent detection method is adopted in the embodiment of the invention, and the useful signal cannot be submerged by noise even if the terminal is in a low signal-to-noise ratio environment (for example, when the signal-to-noise ratio is lower than-10 dB), so that the embodiment of the invention is easy to obtain a good frequency scanning effect even in the low signal-to-noise ratio environment and is easy to reside in a cell with good channel quality.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.
The PSS detection result herein refers to an accumulated value of PSS correlation results at different preset positions over a period of time, where N is N PSS periods, N is less than or equal to 5, and N is a positive integer.
Fig. 1 is a flowchart illustrating a cell search method according to an embodiment of the present invention. The cell search method may be performed by a terminal, for example, an Internet of things (IOT) terminal or a narrowband Internet of things (NB-IOT) terminal.
Specifically, the cell search method may include the steps of:
step S101, determining a current carrier, wherein the current carrier is selected from a frequency point list;
step S102, at least carrying out coherent detection on the current carrier to obtain a coherent detection result of the current carrier;
step S103, when the coherent detection result of the current carrier meets the preset search condition, the cell search dwell is carried out on the current carrier.
In step S101, when the terminal (e.g., UE) is powered on or enters a new area, the terminal may obtain information of each frequency and carrier from the frequency point list, so as to determine a current carrier. In practical application, the frequency points in the frequency point list may be sequentially determined as current frequency points, and the carrier corresponding to the current frequency point may be determined as the current carrier. The frequency points correspond to the carriers one by one.
It should be noted that the carrier may be a center frequency of a synchronization signal (e.g., PSS). For LTE and other systems, the carrier may be the center frequency of the entire downlink bandwidth. For NB-IOT and like systems, the carrier may be an anchor carrier that carries a synchronization channel.
In step S102, the terminal may perform coherent detection on the current carrier, so as to obtain a coherent detection result of the current carrier.
In a variation, the terminal may perform coherent detection on the current carrier and other carriers corresponding to one or more other frequency points in the frequency point list, so as to obtain a coherent detection result of the current carrier and coherent detection results of the other carriers.
For example, the frequency point list includes multiple frequency points, each frequency point is represented by an index, and the terminal can perform coherent detection on the current carrier and carriers corresponding to two other indexes adjacent to the index of the current carrier, respectively, so as to obtain coherent detection results of the current carrier and the other two carriers adjacent to the current carrier.
Since the synchronization signal sequence is a signal sequence known to both the communication parties, the synchronization signal can be detected by blind detection, and the blind detection result can be used as a coherent detection result to coordinate noise and interference with the coherent detection result. Therefore, in an embodiment, the terminal may perform Primary Synchronization Signal (PSS) coherent detection on the current carrier to obtain a PSS detection result of the current carrier. And the PSS coherent detection refers to signal blind detection based on the PSS.
The specific process of the PSS detection is as follows: firstly, correlation calculation is carried out on a filtered received signal starting from a preset position tau (tau is a time variable and comprises a plurality of values) of the ith PSS period and a local PSS sequence, and a correlation result is assumed to be corri(tau), i is more than or equal to 1 and less than or equal to N, and i is a positive integer; secondly, accumulating the correlation results of N PSS periods aiming at the same preset position tau,
Corrsum(τ) represents the accumulation result; and then comparing the accumulation results corresponding to different tau values, solving the maximum accumulation value, and taking the maximum accumulation value as the PSS detection result.
In an embodiment, the terminal may perform PSS coherent detection on the current carrier to obtain a PSS detection result of the current carrier. Further, the terminal may use the obtained PSS detection result as the coherent detection result of the current carrier.
In another embodiment, the terminal may perform PSS coherent detection on the current carrier and use the PSS detection result as a first detection result, and then the terminal may calculate the signal power of the current carrier and use the signal power as a second detection result of the current carrier. Then, the terminal may use a weighted sum of the first detection result and the second detection result as a coherent detection result of the current carrier.
In another embodiment, the terminal may perform PSS coherent detection on the current carrier to obtain a first detection result, and may perform non-coherent detection on the current carrier to obtain a second detection result of the current carrier. Then, the first detection result and the second detection result may be substituted into a preset functional relation, and a calculation result of the functional relation may be used as a coherent detection result of the current carrier.
In a specific implementation, the preset functional relation may be expressed as: f (r _ co, r _ no), where r _ co represents the first detection result, r _ no represents the second detection result, and f (r _ co, r _ no) may represent any functional relation with respect to r _ co, r _ no, for example, f (r _ co, r _ no) ═ r _ co2+r_no2They are not listed here.
In step S103, if the coherent detection result of the current carrier meets a preset search condition, the terminal may temporarily interrupt the scanning process of the remaining carriers (i.e., frequency points) in the frequency point list, and perform cell search on the current carrier to try to reside in the searched cell.
In a specific implementation, the coherent detection result that satisfies the preset search condition may refer to: the coherent detection result exceeds a first preset threshold value.
Alternatively, the coherent detection result satisfying the preset search condition may refer to: the coherent detection result is higher than the first preset threshold, and the coherent detection result of the current carrier is better than the coherent detection results of the other two adjacent carriers, and the other two carriers are also selected from the frequency point list.
In a specific implementation, assuming that a first detection result obtained for the current frequency point (assuming that the frequency point index is k) is r _ co and the second detection result is r _ no, a coherent detection result g (k) corresponding to the current frequency point is r _ co; or, g (k) is p1 · r _ co + p2 · r _ no, p1 and p2 are preset weights; alternatively, g (k) ═ f (r _ co, r _ no). Assuming that Th1 represents the first preset threshold, under this condition, when g (k) > Th1, a cell search camping operation may be performed on the current frequency point; or when g (k) > Th1, and g (k) > g (k-1), g (k) > g (k +1), the cell search camping operation may be performed on the current frequency point, where g (k-1) and g (k +1) are the coherent detection results of the previous frequency point (i.e., the corresponding frequency point index k-1) and the next frequency point (i.e., the corresponding frequency point index k +1), respectively.
When the cell search result meets the preset residing condition, the terminal may perform a cell residing operation to attempt to reside in a cell corresponding to the current carrier. In a specific implementation, if a cell search result is that a cell is searched, and the cell allows the terminal to camp on and a measurement result of the cell satisfies a protocol specification, it means that the cell meets a preset camping condition, and the terminal may attempt to perform a camping operation. And if the terminal successfully resides in the searched cell, ending the cell search process.
In a specific implementation, if the coherent detection result of the current carrier does not satisfy the preset search condition, the coherent detection result of the current carrier may be stored. Further, if the cell search result does not find the cell, or the found cell does not satisfy the preset camping condition, the terminal may store the coherent detection result of the current carrier.
Further, if the cell search result meets the preset residence condition, but the terminal does not reside in the searched cell successfully, the terminal may resume the previously interrupted frequency point scanning process, and continue to scan the next carrier after the current carrier, so as to perform coherent detection on other carriers in the frequency point list. For example, the PSS signals of other carriers are coherently detected to obtain coherent detection results of the other carriers.
Then, for any carrier of the other carriers, it may be determined whether a coherent detection result of the carrier satisfies the preset search condition. If the coherent detection result of the carrier does not satisfy the preset search condition, or the carrier satisfies the preset search condition but the cell search result does not find the cell, or the found cell does not satisfy the preset residence condition, or the attempt of residence on the cell satisfying the preset residence condition fails, the terminal may store the coherent detection results of the other carriers and continue to perform coherent detection on the other carriers in the frequency point list, for example, PSS coherent detection.
Further, if the coherent detection result of a certain remaining carrier meets the preset search condition, cell search and residence may be performed on the carrier, and if no cell is found, or if the found cell does not meet the preset residence condition or fails to reside, the coherent detection result of the carrier may be stored, and the next carrier in the frequency point list may be detected.
If the coherent detection results of all other carriers do not meet the preset search condition or the cell search dwell fails, the terminal may sort the coherent detection results of the carriers in a descending order, so as to obtain N carriers sorted in the top, where N is a positive integer greater than or equal to 1. As a variation, if coherent detection results of one or more other carriers in all other carriers satisfy the preset search condition but do not satisfy the preset camping condition, the terminal may sort the coherent detection results of the carriers in descending order to obtain N carriers sorted in the top, where N is a positive integer greater than or equal to 1.
In a specific implementation, the sorting may be performed according to the coherent detection result. Then, the terminal may determine whether there is a cell that can be successfully camped in the cell search results obtained by the N carriers ranked before, and if the cell is successfully camped on one cell, may stop determining whether the cell search results obtained by the remaining carriers satisfy the preset camping condition, otherwise may sequentially determine the remaining carriers in the N carriers.
Specifically, for the N carriers ranked in the top, the terminal may perform cell search and residence on the cell to which each carrier belongs in sequence according to the ranking order, and gradually determine whether the cell is searched on the carrier, whether the searched cell meets the preset residence condition, and whether residence is successful on the cell meeting the preset residence condition. If the cell search camping result fails, the terminal can continue to perform cell search camping on the remaining carriers in the N carriers, so as to determine whether a suitable cell can be searched and camped on.
Further, if a cell that can be successfully camped on cannot be found (for example, cell search camping fails) in the process of cell search camping on the N carriers ranked in the top, the terminal determines whether the number of times of cell search reaches a preset maximum frequency scanning. If the preset maximum frequency scanning times are reached, the terminal can terminate frequency scanning and cell searching, and the frequency scanning fails and the cell searching fails. If not, the terminal may add 1 to the frequency scanning number, and repeat the above frequency scanning and cell searching processes to attempt to search for and camp on a suitable cell.
Those skilled in the art will understand that the cell search camping failure may refer to: the cell search result is that no cell is searched, or although the cell search result is that a cell is searched, the cell meets a preset residing condition, or the cell meets the preset residing condition, but the terminal fails to attempt to reside in the cell.
Fig. 2 is a flowchart illustrating a cell search method according to another embodiment of the present invention. The cell search method performs frequency scanning using a synchronization signal. Specifically, the terminal can detect the PSS signal on the carrier in a short time using a PSS correlator (matched filter).
More specifically, the cell search method may include the steps of:
step S201, determining a current carrier based on the frequency point list, that is, the terminal takes each carrier frequency in the frequency point list as the current carrier in sequence.
After determining the current carrier, the terminal may perform coherent detection (e.g., PSS coherent detection) in step S202, that is, the terminal may perform PSS coherent detection on the current carrier to obtain a coherent detection result of the carrier. In a specific implementation, the terminal may sequentially input carriers to the PSS correlators to perform carrier scanning (carriers scanning loop).
Further, the terminal performs step S203 to determine whether the coherent detection result of the carrier meets a preset search condition? In a specific implementation, in different systems, the results of coherent detection of the carrier meeting the preset search condition may be different.
For example, the fact that the coherent detection result of the carrier meets the preset search condition means that the PSS detection result of the current carrier exceeds a first preset threshold.
For another example, the coherent detection result of the carrier meeting the preset search condition means that the coherent detection result of the current carrier not only exceeds a second preset threshold, but also is greater than the coherent detection result of at least one other carrier (for example, two adjacent carriers) adjacent to the current carrier, where the second preset threshold may be less than or equal to the first preset threshold. In other communication scenarios, the coherent detection result satisfying the preset search condition may be set according to an actual condition, which is not limited herein.
Further, if the coherent detection result of the carrier meets the preset search condition, the terminal may interrupt the "carrier scanning loop" and perform step S2041, that is, perform cell search based on the current carrier and attempt to camp on the searched cell.
And if the coherent detection result of the carrier does not meet the preset search condition, executing step S2042, and storing the coherent detection result of the carrier. The coherent detection results of the carriers may be stored by the terminal for subsequent use.
Further, in step S2051, it is determined whether the cell search camping result is successful to camp on? If yes, the frequency scanning and cell search dwell process is ended. If not, the terminal may go to step S2052 to determine whether to traverse all the frequency points in the frequency point list.
Further, in step S2052, it is determined whether all frequency points in the frequency point list are traversed? If not, go to step S201; if so, that is, all carriers are searched, step S206 is executed, that is, the coherent detection results of all carriers are sorted to obtain the top N carriers. Specifically, the terminal may arrange the coherent detection results of all carriers in a descending order, so as to obtain N carriers ranked in the top.
Further, step S207 is executed to determine whether to traverse the N carriers? If not, cell search is performed on the carriers in the N carriers according to the ranking order of the N carriers, that is, step S2081 is performed, cell search is performed on the remaining carriers in the N carriers in order, and camping is attempted on the searched cells.
Further, the terminal may perform step S2091, i.e., determine whether the cell camping is successful. If not, go to step S207; if successful, the frequency scanning and cell search procedure is ended.
Further, if the N carriers are traversed but no suitable cell for camping is obtained, step S2082 is performed, i.e., it is determined whether the maximum frequency scanning times? If not, the maximum frequency scanning times are not reached, all the frequency points can be reset to be in an unsearched state, namely step S2083 is executed, the frequency point list is reset, and the step S201 is switched to; if yes, indicating that the maximum frequency scanning number is reached, step S2092 may be executed, where the frequency scanning fails and the frequency scanning process is ended.
Fig. 3 is a schematic structural diagram of a cell search apparatus according to an embodiment of the present invention. The cell search apparatus 3 may implement the method solutions shown in fig. 1 and fig. 2, and is executed by the terminal.
Specifically, the cell search apparatus 3 may include: a determining module 301 adapted to determine a current carrier, where the current carrier is selected from a frequency point list; a first detecting module 302, adapted to perform coherent detection on at least the current carrier to obtain a coherent detection result of the current carrier; the searching module 303 is adapted to perform cell search and residence on the current carrier when the coherent detection result of the current carrier meets a preset search condition.
Further, the cell search apparatus 3 may further include: a first resident module 304. If the cell search result is that a cell is searched, and the cell meets a preset camping condition, the first camping module 304 is adapted to attempt to camp on the cell.
In a specific implementation, the fact that the coherent detection result satisfies the preset search condition may refer to: the coherent detection result exceeds a first preset threshold, or the coherent detection result exceeds the first preset threshold and is superior to coherent detection results of other two carriers, the other two carriers are selected from the frequency point list, and the index of the current carrier is between the indexes of the other two carriers.
In a specific implementation, the cell search apparatus 3 may further include: a second detecting module 305, adapted to perform coherent detection on each other carrier in the frequency point list one by one to obtain coherent detection results of each other carrier when the coherent detection result of the current carrier does not satisfy the preset search condition or satisfies the preset search condition but fails to search for a cell residence result; a sorting module 306. If the coherent detection results of all other carriers do not satisfy the preset search condition, or the search of the resident results in other carrier cells satisfying the preset search condition fails, the sorting module 306 is adapted to sort the coherent detection results of all carriers in the frequency point list in a descending order to obtain N carriers sorted in the top, where N is a positive integer greater than or equal to 1; the second camping module 307 is adapted to attempt to camp on the cell satisfying the preset camping condition when there is a cell satisfying the preset camping condition in the cell search results obtained by the N carriers ranked in the top.
In a specific implementation, the failure of the cell search camping result may refer to: the cell search result is that the cell is not searched, or the cell search result is that the cell is searched, but the cell does not meet the preset resident condition; or, the cell search result is that a cell is searched, and the cell meets the preset residing condition, but the result of trying to reside fails.
In a specific implementation, the cell search apparatus 3 may further include: a first storage module 308, adapted to store a coherent detection result of the current carrier when the coherent detection result of the current carrier does not satisfy the preset search condition, or when the coherent detection result of the current carrier satisfies the preset search condition but the cell search camping fails; the second storing module 309 is adapted to store the coherent detection results of the other carriers when the coherent detection results of the other carriers do not satisfy the preset search condition, or the coherent detection results of the other carriers satisfy the preset search condition but the cell search camping fails.
In a specific implementation, the second residence module 307 may include: the determining submodule 3071 is adapted to, for the N carriers ranked in the front, sequentially perform cell search on each carrier according to the ranking order, and attempt to camp on the cell that meets the preset camping condition.
In a specific implementation, the cell search apparatus 3 may further include: the module 3010 is terminated. If the cell search camping fails and the preset maximum frequency scanning times are reached in the process of performing the cell search camping on the N carriers ranked in the front, the termination module 3010 is adapted to terminate the frequency scanning and the cell search.
In a specific implementation, the first detection module 302 may include: the first detection sub-module 3021 is adapted to perform PSS coherent detection on the current carrier, and use an obtained PSS detection result as a coherent detection result of the current carrier.
In a specific implementation, the first detection module 302 may include: a second detection sub-module 3022, adapted to perform PSS coherent detection on the current carrier to obtain a first detection result of the current carrier; a calculating submodule 3023, adapted to calculate a signal power on the current carrier to obtain a second detection result of the current carrier; a first generating sub-module 3024 adapted to use a weighted sum of the first detection result and the second detection result as a coherent detection result of the current carrier.
In a specific implementation, the first detection module 302 may include: a third detection sub-module 3025, adapted to perform PSS coherent detection on the current carrier to obtain a first detection result of the current carrier; a fourth detection submodule 3026, adapted to perform non-coherent detection on the current carrier to obtain a second detection result of the current carrier; the second generating sub-module 3027 is adapted to substitute the first detection result and the second detection result into a preset functional relation to perform calculation, and use the calculation result as the coherent detection result of the current carrier.
For more contents of the operation principle and the operation mode of the cell search apparatus 3, reference may be made to the related description of the technical solutions in fig. 1 and fig. 2, which is not repeated here.
Further, the embodiment of the present invention also discloses a storage medium, on which computer instructions are stored, and when the computer instructions are executed, the technical solutions of the methods described in the embodiments shown in fig. 1 and fig. 2 are executed. Preferably, the storage medium may include a computer-readable storage medium such as a non-volatile (non-volatile) memory or a non-transitory (non-transient) memory. The computer readable storage medium may include ROM, RAM, magnetic or optical disks, and the like.
Further, an embodiment of the present invention further discloses a terminal, which includes a memory and a processor, where the memory stores computer instructions capable of being executed on the processor, and the processor executes the technical solution of the method in the embodiment shown in fig. 1 and fig. 2 when executing the computer instructions. Preferably, the terminal may be an IOT terminal or an NB-IOT terminal.
Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (13)
1. A method of cell search, comprising:
determining a current carrier, wherein the current carrier is selected from a frequency point list;
at least carrying out coherent detection on the current carrier to obtain a coherent detection result of the current carrier;
when the coherent detection result of the current carrier meets the preset search condition, carrying out cell search residence on the current carrier;
when the coherent detection result of the current carrier does not meet the preset search condition or meets the preset search condition but the cell search resident result fails, performing coherent detection on each other carrier in the frequency point list one by one to obtain the coherent detection result of each other carrier; if the coherent detection results of all other carriers do not meet the preset search condition, sequencing the coherent detection results of all carriers in the frequency point list in a descending order to obtain N carriers which are sequenced at the front, wherein N is a positive integer greater than or equal to 1; and when the cell search results obtained by the N carriers sequenced in the front have a cell meeting a preset residence condition, trying to reside in the cell meeting the preset residence condition.
2. The cell search method of claim 1, further comprising:
and if the cell search result is that a cell is searched and the cell meets a preset residing condition, attempting to reside in the cell.
3. The cell search method of claim 1, wherein the coherent detection result satisfying a preset search condition is:
the coherent detection result exceeds a first preset threshold, or the coherent detection result exceeds the first preset threshold and is superior to coherent detection results of other two carriers, the other two carriers are selected from the frequency point list, and the index of the current carrier is between the indexes of the other two carriers.
4. The cell search method of claim 1, wherein the cell search camping result failure means: the cell search result is that the cell is not searched; or,
the cell search result is that a cell is searched, but the cell does not meet the preset residence condition; or,
the cell search result is that a cell is searched, and the cell meets the preset residence condition, but the attempt to reside results in failure.
5. The cell search method of claim 4, further comprising:
when the coherent detection result of the current carrier does not meet the preset search condition, or the coherent detection result of the current carrier meets the preset search condition but the cell search lingers unsuccessfully, storing the coherent detection result of the current carrier;
and when the coherent detection results of the other carriers do not meet the preset search condition, or the coherent detection results of the other carriers meet the preset search condition but the cell search dwell fails, storing the coherent detection results of the other carriers.
6. The cell search method according to claim 1, wherein the attempting to camp on the cell satisfying the predetermined camping condition when there is a cell satisfying the predetermined camping condition in the cell search results obtained from the top N carriers comprises:
and for the N carriers which are sequenced at the front, sequentially carrying out cell search on each carrier according to the sequencing order, and trying to reside the cell which meets the preset residence condition.
7. The cell search method of claim 1, further comprising:
and if the cell search residence fails and the preset maximum frequency scanning times are reached in the process of carrying out the cell search residence on the N carriers sequenced at the front, terminating the frequency scanning and the cell search.
8. The cell search method according to any of claims 1 to 7, wherein the performing coherent detection on at least the current carrier to obtain a coherent detection result of the current carrier comprises:
and carrying out PSS coherent detection on the current carrier, and taking the obtained PSS detection result as the coherent detection result of the current carrier.
9. The cell search method according to any of claims 1 to 7, wherein the performing coherent detection on at least the current carrier to obtain a coherent detection result of the current carrier comprises:
PSS coherent detection is carried out on the current carrier wave to obtain a first detection result of the current carrier wave;
calculating the signal power on the current carrier to obtain a second detection result of the current carrier; and taking the weighted sum of the first detection result and the second detection result as the coherent detection result of the current carrier.
10. The cell search method according to any of claims 1 to 7, wherein the performing coherent detection on at least the current carrier to obtain a coherent detection result of the current carrier comprises:
PSS coherent detection is carried out on the current carrier wave to obtain a first detection result of the current carrier wave;
carrying out incoherent detection on the current carrier to obtain a second detection result of the current carrier;
and substituting the first detection result and the second detection result into a preset function relation to calculate, and taking the calculation result as the coherent detection result of the current carrier.
11. A cell search apparatus, comprising:
a determining module adapted to determine a current carrier, the current carrier being selected from a list of frequency points;
the first detection module is suitable for carrying out coherent detection on at least the current carrier to obtain a coherent detection result of the current carrier;
the search module is suitable for searching and residing the current carrier in a cell when the coherent detection result of the current carrier meets the preset search condition;
the search module is further adapted to perform coherent detection on each other carrier in the frequency point list one by one to obtain coherent detection results of each other carrier when the coherent detection result of the current carrier does not satisfy the preset search condition or the preset search condition is satisfied but the cell search resident result fails; if the coherent detection results of all other carriers do not meet the preset search condition, sequencing the coherent detection results of all carriers in the frequency point list in a descending order to obtain N carriers sequenced at the front, wherein N is a positive integer greater than or equal to 1; and when the cell search results obtained by the N carriers sequenced in the front have a cell meeting a preset residence condition, trying to reside in the cell meeting the preset residence condition.
12. A storage medium having stored thereon computer instructions, which when executed by a processor, perform the steps of the method of any one of claims 1 to 10.
13. A terminal comprising a memory and a processor, the memory having stored thereon computer instructions executable on the processor, wherein the processor, when executing the computer instructions, performs the steps of the method of any one of claims 1 to 10.
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