CN106686668B - method and device for selecting voice fallback cell - Google Patents
method and device for selecting voice fallback cell Download PDFInfo
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- H04W36/0005—Control or signalling for completing the hand-off
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- H04W36/0061—Transmission or use of information for re-establishing the radio link of neighbour cell information
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- H—ELECTRICITY
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- H04W36/0005—Control or signalling for completing the hand-off
- H04W36/0055—Transmission or use of information for re-establishing the radio link
- H04W36/0066—Transmission or use of information for re-establishing the radio link of control information between different types of networks in order to establish a new radio link in the target network
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
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- H04W36/0005—Control or signalling for completing the hand-off
- H04W36/0083—Determination of parameters used for hand-off, e.g. generation or modification of neighbour cell lists
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- H—ELECTRICITY
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Abstract
The invention relates to the field of safety protection, and discloses a method and a device for selecting a voice fallback cell, wherein the method comprises the following steps: taking a global system for mobile communications (GSM) cell with a distance to a Long Term Evolution (LTE) cell within a first range as a candidate cell for the LTE cell voice fallback; selecting a cell having a mutual co-channel interference relationship with a candidate cell as an associated cell of the candidate cell; determining the cell quality index of the candidate cell according to the carrier number of the associated cell of the candidate cell and the number of the frequency points in the associated cell of the candidate cell, which is the same as the frequency points in the candidate cell; and selecting one candidate cell as the voice fallback cell of the LTE cell according to the cell quality index of each candidate cell. The embodiment of the invention solves the problem that the terminal can not be ensured to occupy the cell with good GSM network quality when the voice falls back in the prior art, and the 4G network conversation quality is influenced.
Description
Technical Field
the present invention relates to the field of communications technologies, and in particular, to a method and an apparatus for selecting a voice fallback cell.
Background
CSFB (Circuit Switched Fallback) is a voice solution defined by 3GPP (3 rd Generation Partnership Project), and uses a mature GSM (Global System for Mobile communications) network to carry voice services, that is, when a user is resident in an LTE (Long Term Evolution) network and initiates a voice service, the user will fall back to the GSM network and perform the voice service on the GSM network. The fallback mechanism is a key factor that determines the performance of the CSFB scheme and affects the user voice service experience. The fallback mechanism currently used in the network is mainly based on RRC (Radio Resource Control) redirection of R8 version.
In the prior art, when a terminal initiates a voice service, a network redirects the terminal from a 4G LTE network to a 2G GSM network, but which cell frequency point of the GSM network the terminal is redirected to is selected based on a signal strength measurement result of each frequency point by the terminal. The network releases the 4G network connection and simultaneously issues a GSM frequency point list, the terminal selects a frequency point with the strongest signal intensity by measuring the frequency points in the frequency point list, initiates an access request to the 2G network and then reads 2G broadcast information for synchronization, and finally accesses the 2G network to complete CSFB fallback. The other mode is that the network does not issue any GSM frequency point information, the terminal searches the frequency range by itself according to the setting of the mobile phone, selects a frequency point with the strongest signal intensity, initiates an access request to the 2G network, then reads the 2G broadcast information for synchronization, and finally accesses the 2G network to complete CSFB fallback.
The existing scheme is a blind redirection scheme, a server cannot control the process of redirecting a terminal to a GSM network, although frequency point information of the GSM can be issued while 4G network connection is released, in a plurality of GSM frequency points, the quality grade of the frequency point cannot be distinguished, the GSM frequency point redirected by the terminal cannot be selected, and the signal intensity of the frequency point measured by the terminal is completely determined. But stronger signal strength of a frequency point does not represent better quality of the network. Therefore, when the terminal falls back to the GSM network, it cannot be guaranteed to occupy a cell with good GSM quality, which affects the quality of 4G network call.
Disclosure of Invention
the embodiment of the invention provides a method and a device for selecting a voice fallback cell, which solve the problem that in the prior art, when voice fallback is performed, a terminal cannot be guaranteed to occupy a cell with good GSM network quality, and the 4G network call quality is influenced.
The method for selecting the voice fallback cell provided by the embodiment of the invention comprises the following steps:
taking a global system for mobile communications (GSM) cell with a distance to a Long Term Evolution (LTE) cell within a first range as a candidate cell for the LTE cell voice fallback;
selecting a cell having a mutual co-channel interference relationship with a candidate cell as an associated cell of the candidate cell;
Determining the cell quality index of the candidate cell according to the carrier number of the associated cell of the candidate cell and the number of the frequency points in the associated cell of the candidate cell, which is the same as the frequency points in the candidate cell;
and selecting one candidate cell as the voice fallback cell of the LTE cell according to the cell quality index of each candidate cell.
optionally, the selecting, as the associated cell of the candidate cell, a cell having a co-channel interference relationship with the candidate cell includes:
acquiring a cell with the distance to the candidate cell within a second range, and taking the cell as a neighboring cell of the candidate cell;
Acquiring the signal intensity of a plurality of sampling points of a neighboring cell of the candidate cell;
determining the ratio of the number of sampling points of which the difference between the signal intensity of the candidate cell and the signal intensities of a plurality of sampling points in a neighboring cell of the candidate cell is less than a first threshold value to the number of all sampling points in the neighboring cell;
And if the ratio is larger than a second threshold value, the adjacent cell is a cell which has a mutual co-channel interference relationship with the candidate cell.
optionally, the determining the cell quality index of each candidate cell according to the number of carriers of the associated cell of each candidate cell and the number of frequency points in the associated cell of each candidate cell, which are the same as the frequency points of the corresponding candidate cell, includes:
Determining the cell carrier index of the candidate cell according to the sum of the carrier numbers of all the associated cells of the candidate cell;
determining the cell co-frequency index of the candidate cell according to the sum of the same number of the frequency points of all the associated cells of the candidate cell and the frequency points of the candidate cell;
and determining the cell quality index of the candidate cell according to the cell carrier index and the cell co-frequency index of the candidate cell.
Optionally, the cell quality index of the candidate cell satisfies the following formula:
cell quality index ═ a1X cell carrier index + a2X cell co-frequency index;
wherein, a1a weighting factor being the cell carrier index, a2And the weighting coefficient is the same frequency index of the cell.
optionally, the selecting one candidate cell as the voice fallback cell of the LTE cell according to the cell quality index of each candidate cell includes:
dividing all candidate cells into high-priority candidate cells and low-priority candidate cells according to the cell quality index of each candidate cell;
acquiring the signal strength of the main signal of each candidate cell;
comparing the signal strength of the main signal of each high-priority candidate cell with a first threshold value, and selecting the high-priority candidate cell of which the signal strength of the main signal is greater than the first threshold value;
Comparing the signal strength of the main signal of each low-priority candidate cell with a second threshold value, and selecting the low-priority candidate cell of which the signal strength of the main signal is greater than the second threshold value;
and selecting the candidate cell with the minimum cell quality index as the voice fallback cell of the LTE cell from the high-priority candidate cell with the signal strength of the main signal larger than the first threshold and the low-priority candidate cell with the signal strength of the main signal larger than the second threshold.
Optionally, the dividing all the candidate cells into the high-priority candidate cell and the low-priority candidate cell according to the cell quality index of each candidate cell includes:
Ranking all candidate cells according to the cell quality indexes of the candidate cells, wherein the candidate cells with smaller cell quality indexes are ranked more front;
and taking N candidate cells with the top rank as the high-priority candidate cells, and taking the candidate cells except the high-priority candidate cells in all the candidate cells as the low-priority candidate cells.
an apparatus for selecting a voice fallback cell, comprising:
the candidate cell module is used for taking a GSM cell with a distance to an LTE cell within a first range as a candidate cell for the LTE cell to fall back;
the associated cell module is used for selecting a cell which has a mutual co-channel interference relationship with the candidate cell as an associated cell of the candidate cell;
a parameter determining module, configured to determine a cell quality index of the candidate cell according to the number of carriers of the associated cell of the candidate cell, and the number of frequency points in the associated cell of the candidate cell that is the same as the number of frequency points in the candidate cell;
and the voice fallback module is used for selecting one candidate cell as the voice fallback cell of the LTE cell according to the cell quality index of each candidate cell.
Optionally, the associated cell module is further configured to:
acquiring a cell with the distance to the candidate cell within a second range, and taking the cell as a neighboring cell of the candidate cell;
acquiring the signal intensity of a plurality of sampling points of a neighboring cell of the candidate cell;
determining the ratio of the number of sampling points of which the difference between the signal intensity of the candidate cell and the signal intensities of a plurality of sampling points in a neighboring cell of the candidate cell is less than a first threshold value to the number of all sampling points in the neighboring cell;
and if the ratio is larger than a second threshold value, the adjacent cell is a cell which has a mutual co-channel interference relationship with the candidate cell.
optionally, the parameter determining module is further configured to:
Determining the cell carrier index of the candidate cell according to the sum of the carrier numbers of all the associated cells of the candidate cell;
Determining the cell co-frequency index of the candidate cell according to the sum of the same number of the frequency points of all the associated cells of the candidate cell and the frequency points of the candidate cell;
and determining the cell quality index of the candidate cell according to the cell carrier index and the cell co-frequency index of the candidate cell.
Optionally, the cell quality index of the candidate cell satisfies the following formula:
cell quality index ═ a1X cell carrier index + a2X cell co-frequency index;
Wherein, a1a weighting factor being the cell carrier index, a2and the weighting coefficient is the same frequency index of the cell.
Optionally, the voice fallback module is further configured to:
Dividing all candidate cells into high-priority candidate cells and low-priority candidate cells according to the cell quality index of each candidate cell;
Acquiring the signal strength of the main signal of each candidate cell;
Comparing the signal strength of the main signal of each high-priority candidate cell with a first threshold value, and selecting the high-priority candidate cell of which the signal strength of the main signal is greater than the first threshold value;
Comparing the signal strength of the main signal of each low-priority candidate cell with a second threshold value, and selecting the low-priority candidate cell of which the signal strength of the main signal is greater than the second threshold value;
And selecting the candidate cell with the minimum cell quality index as the voice fallback cell of the LTE cell from the high-priority candidate cell with the signal strength of the main signal larger than the first threshold and the low-priority candidate cell with the signal strength of the main signal larger than the second threshold.
optionally, the voice fallback module is further configured to:
Ranking all candidate cells according to the cell quality indexes of the candidate cells, wherein the candidate cells with smaller cell quality indexes are ranked more front;
and taking N candidate cells with the top rank as the high-priority candidate cells, and taking the candidate cells except the high-priority candidate cells in all the candidate cells as the low-priority candidate cells.
When the embodiment of the invention selects the voice fallback cell, the same frequency interference and influence of the peripheral cells on the selected cell are considered. The GSM cell in the first range is used as a candidate cell, the associated cell with mutual co-frequency interference with the candidate cell is selected, the quality index of the candidate cell can be determined according to the carrier number of the associated cell and the frequency point same as the candidate cell, the GSM network quality of each candidate cell is quantized, the network quality grade of each candidate cell can be distinguished, the candidate cell with high network quality is selected as the voice fallback cell of the LTE cell, the occupation of the terminal on the cell with good GSM network quality is guaranteed, and the voice call quality of the 4G LTE network is further guaranteed.
drawings
in order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.
fig. 1 is a flowchart of a method for selecting a voice fallback cell in an embodiment of the present invention;
fig. 2 is a schematic diagram of a maximum fully associated cell set according to an embodiment of the present invention;
FIG. 3 is a flowchart of another method for selecting a fallback cell in accordance with the present invention;
fig. 4 is a block diagram of an apparatus for selecting a voice fallback cell in an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail with reference to the accompanying drawings, and it is apparent that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The existing CSFB voice fallback scheme is a blind redirection scheme from a 4G LTE network to a 2G GSM network, and finally the frequency point of a cell to be fallback is completely determined by a terminal according to the measured signal strength. But a large signal strength does not represent a good signal quality. The signal quality, namely the quality of the wireless network, is divided into 8 grades of 0-7 according to the current evaluation standard, wherein the grade 0 is the best grade, and the grade 7 is the worst grade. The quality of the wireless network is related to the carrier-to-interference ratio, which is the ratio of the useful signal strength to the interference signal strength in the received signal, and the specific mapping relationship is as shown in table 1:
| Quality class of wireless network | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| carrier to interference ratio (C/I) | 23 | 19 | 17 | 15 | 13 | 11 | 8 | 4 |
TABLE 1
where C is the strength of the useful signal, I is the strength of the interfering signal, and table 1 is the correspondence between the empirical value of the quality level of the wireless network and the carrier-to-interference ratio. As can be seen from table 1, the larger the C/I value is, the better the quality of the wireless network is, so the stronger the strength of the useful signal is, the weaker the strength of the interference signal is, and the better the quality of the wireless network is. Therefore, the communication quality of the frequency point of one cell needs to be measured by considering not only the strength of the received signal but also the interference generated by other cells to the cell.
based on this, an embodiment of the present invention provides a method for selecting a voice fallback cell, where a flow of the method is shown in fig. 1, and the method may include the following steps:
S101, a global system for mobile communications (GSM) cell with a distance to a Long Term Evolution (LTE) cell within a first range is used as a candidate cell for the voice fallback of the LTE cell;
s102, selecting a cell having a mutual co-channel interference relationship with a candidate cell as an associated cell of the candidate cell;
s103, determining the cell quality index of the candidate cell according to the carrier number of the associated cell of the candidate cell and the number of the frequency points in the associated cell of the candidate cell, which is the same as the frequency points in the candidate cell;
s104, selecting one candidate cell as the voice fallback cell of the LTE cell according to the cell quality index of each candidate cell.
in the embodiment of the invention, when the voice fallback cell is selected, the interference to the cell frequency point is also brought into the measurement standard, the GSM cell in the first range is taken as a candidate cell, and the associated cell with the same frequency interference with the candidate cell is selected. The first range of the candidate cell is generally determined according to the distance between the base stations, and can be 2-3 times of the distance between the base stations. The first range under different scenes has different values, for example, a dense urban area can have a value of 200 m-300 m, a village and a town can have a value of 500-600 m, and a rural area can have a value of 700 m-1000 m.
the quality index of the candidate cell is determined according to the carrier number of the associated cell and the frequency point which is the same as the candidate cell, so that the GSM network quality of each candidate cell is quantized, the network quality grade of each candidate cell can be distinguished, the candidate cell with high network quality is selected as the voice fallback cell of the LTE cell, the occupation of the terminal on the cell with good GSM network quality is ensured, and the voice call quality of the 4G LTE network is further ensured.
the interference in the cell mainly comes from the adjacent cells, and the more adjacent cells of the cell, the closer the signals of the cell and the adjacent cells are, the greater the interference strength of the cell is. And in the adjacent cells of the candidate cell, the cell which has the mutual co-channel interference relationship with the candidate cell is the associated cell of the candidate cell. The two cells A and B have mutual same frequency interference relationship, namely the cell A has the same frequency restriction effect on the cell B, and the cell B has the same frequency restriction effect on the cell A, namely the cell A and the cell B are mutually related cells. The mutual interference between the associated cells is serious, so the embodiment of the invention mainly considers the interference of the associated cell of the candidate cell to the candidate cell.
Preferably, the associated cell of the candidate cell may be determined by:
acquiring a cell with the distance to the candidate cell within a second range, and taking the cell as a neighboring cell of the candidate cell;
acquiring the signal intensity of a plurality of sampling points of a neighboring cell of the candidate cell;
Determining the ratio of the number of sampling points of which the difference between the signal intensity of the candidate cell and the signal intensities of a plurality of sampling points in a neighboring cell of the candidate cell is less than a first threshold value to the number of all sampling points in the neighboring cell;
and if the ratio is larger than a second threshold value, the adjacent cell is a cell which has a mutual co-channel interference relationship with the candidate cell.
The embodiment of the invention selects the cells within a certain range around the GSM candidate cell as the neighboring cells which can cause co-channel interference to the candidate cell. And acquiring the signal intensity of a plurality of sampling points of the adjacent cell from the measurement report of the adjacent cell, and calculating the difference value between the signal intensity of the candidate cell and the signal intensity of the sampling points. And dividing the number of the sampling points with the difference value smaller than the first threshold value by the number of all the sampling points of the adjacent cell, and comparing the ratio obtained by the division with a second threshold value, wherein the adjacent cell with the ratio larger than the second threshold value has mutual co-frequency interference with the candidate cell. That is, in the data measured in the neighboring cell, if the ratio of the signal strength close to the signal strength of the candidate cell is large, the cell is considered to be the associated cell of the candidate cell.
optionally, on the basis of all the associated cells of the candidate cell, a concept of a maximum fully associated cell set may also be introduced. If any cell in the cell set psi is an associated cell and there is no other associated cell set phi, so that the cell set psi belongs to phi, the cell set psi is the maximum fully associated cell set. As shown in fig. 2, cells A, B, C and D are the largest fully associated set of cells. The associated cells in steps S103 to S104 may also be limited to associated cells in the same maximum fully associated cell set as the candidate cells.
the wireless frequency spectrum in the mobile communication network is limited, and a mode of same-frequency multiplexing cell networking needs to be adopted to provide mobile communication service, that is, users in cells at a certain distance can use the same frequency, so that the frequency spectrum efficiency is greatly improved, but the cost is that an interference signal I is introduced. In the embodiment of the present invention, users in the candidate cell and the associated cell of the candidate cell may use the same frequency. And assuming that the coverage radius of all base stations is the same, the coverage radius of the candidate cell is R, and the same-frequency multiplexing distance is D. The multiplexing distance D, the cell radius R and the cell number N of each frequency multiplexing cluster satisfy the following relations:
… … … … … … … … … … … … … … equation 1
In the above formula, q is the co-channel interference attenuation factor, 3N is the frequency reuse coefficient, and for the directional cell, the actual physical meaning of N is the number of base stations in the frequency reuse cluster. The frequency reuse factor satisfies the following relationship:
frequency reuse factor (total frequency available/sum of carriers of all associated cells) … … formula 2
If the associated cell and the candidate cell work simultaneously, the mobile phone in the central candidate cell receives both the useful signal transmitted by the base station of the cell and the interference signal of the associated cell. Then the lowest intra-frequency carrier-to-interference ratio (C/I) at the edge of the candidate cell can be expressed as:
… … … … … … … … … … equation 3
where γ is the propagation path loss exponent determined by the terrain.
according to the formulas 1 to 3, the carrier-to-interference ratio of the candidate cell and the sum of the carrier numbers of all the associated cells are in an inverse proportion relation, that is, the larger the sum of the carrier numbers of all the associated cells of the candidate cell is, the smaller the carrier-to-interference ratio of the candidate cell is, and thus the worse the wireless network quality of the candidate cell is. Therefore, the cell quality index of the candidate cell can be determined according to the sum of the carrier numbers of all the associated cells of the candidate cell.
on the other hand, obviously, the more frequency points used by the associated cell of the candidate cell and the candidate cell are the same, the greater the interference to the candidate cell is.
therefore, preferably, the cell quality index of the candidate cell is determined according to the number of carriers of each associated cell of the candidate cell and the number of frequency points in each associated cell of the candidate cell, which are the same as the frequency points of the corresponding candidate cell, that is, step S103 includes:
determining the cell carrier index of the candidate cell according to the sum of the carrier numbers of all the associated cells of the candidate cell;
Determining the cell co-frequency index of the candidate cell according to the sum of the same number of the frequency points of all the associated cells of the candidate cell and the frequency points of the candidate cell;
and determining the cell quality index of the candidate cell according to the cell carrier index and the cell co-frequency index of the candidate cell.
specifically, after determining the associated cells of the candidate cell, the cell carrier index and the cell co-frequency index of the candidate cell may be determined, where the cell carrier index is the sum of the carrier numbers of all the associated cells of the candidate cell, and the cell co-frequency index is the sum of the same number of frequency points of all the associated cells of the candidate cell as the frequency points of the candidate cell.
For example, if the candidate cell D has three associated cells, which are cell a, cell B, and cell C, respectively, the candidate cell has 6 frequency points; cell a has 8 frequency points, of which 2 frequency points are shared with the candidate cells; the cell B has 5 frequency points, wherein 1 frequency point is shared with the candidate cell; cell C has 9 frequency bins, of which 2 are shared with the candidate cells. Since the frequency point number and the carrier number of the cell are equal, the cell carrier index of the candidate cell is 8+5+ 9-22, and the cell co-frequency index is 2+1+ 2-5.
Further, an evaluation table of the cell wireless network quality can be respectively established according to the cell carrier index and the cell co-frequency index of the candidate cell, as shown in tables 2 and 3:
| cell carrier index | quality class of wireless network |
| 0-20 | 0 |
| 21-40 | 1 |
| 41-60 | 2 |
| 61-80 | 3 |
| 81-100 | 4 |
| 101-150 | 5 |
| >150 | 6 |
TABLE 2
| Cell co-frequency index | quality class of wireless network |
| 1 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 3 |
| 5 | 4 |
| 6 | 5 |
| >6 | 6 |
TABLE 3
It can be seen from tables 2 and 3 that both the cell carrier index and the cell co-frequency index are inversely proportional to the wireless network quality grade of the cell, i.e., the larger the cell carrier index is, the worse the wireless network quality of the cell is, the larger the cell co-frequency index is, the worse the wireless network quality of the cell is. If the wireless network quality grade of the candidate cell D is 1 according to the cell carrier index; and if the same frequency index of the cell is independently used, the wireless network quality grade of the candidate cell D is 4. Therefore, a value, namely a cell quality index, needs to be determined according to the cell carrier index and the cell co-frequency index, and is used as a standard for judging the quality of a cell wireless network.
thus, the cell quality index of the candidate cell satisfies the following formula:
Cell quality index ═ a1x cell carrier index + a2X cell co-frequency index … … … … … … formula 4
Wherein, a1A weighting factor being the cell carrier index, a2And the weighting coefficient is the same frequency index of the cell. Considering the different influence degree of the same frequency and the adjacent frequency on the cell signal, a1Can be taken to be 20% -30%, a2Can be selected from 70% to 80%, and a1+a2＝100％。
after the cell quality index of the candidate cell for the LTE cell voice fallback is determined, the final voice fallback cell still needs to be selected according to the signal strength of each candidate cell. For the purpose of comparison, the candidate cells may be divided into high priority candidate cells and low priority candidate cells according to the cell quality index, and then the threshold values of the signal strengths may be determined for different priorities. Preferably, step S104 includes:
dividing all candidate cells into high-priority candidate cells and low-priority candidate cells according to the cell quality index of each candidate cell;
Acquiring the signal strength of the main signal of each candidate cell;
Comparing the signal strength of the main signal of each high-priority candidate cell with a first threshold value, and selecting the high-priority candidate cell of which the signal strength of the main signal is greater than the first threshold value;
Comparing the signal strength of the main signal of each low-priority candidate cell with a second threshold value, and selecting the low-priority candidate cell of which the signal strength of the main signal is greater than the second threshold value;
And selecting the candidate cell with the minimum cell quality index as the voice fallback cell of the LTE cell from the high-priority candidate cell with the signal strength of the main signal larger than the first threshold and the low-priority candidate cell with the signal strength of the main signal larger than the second threshold.
specifically, a candidate cell with a small cell quality index is set to a high priority, and a candidate cell with a large cell quality index is set to a low priority. The first threshold value of the high priority candidate cell and the second threshold value of the low priority candidate cell may be set to the same value, or both may be set to different values. Preferably, the first threshold of the high priority candidate cell may be slightly lower than the second threshold of the low priority candidate cell, because the high priority candidate cell receives less interference, and thus the requirement for signal strength may be reduced to some extent. For example, the first threshold value of the high priority candidate cell may be set to-100 dBm and the second threshold value of the low priority candidate cell may be set to-90 dBm. And selecting a cell with the signal strength exceeding a first threshold value from all high-priority candidate cells, selecting a cell with the signal strength exceeding a second threshold value from all low-priority candidate cells, and then taking the candidate cell with the minimum cell quality index as a voice fallback cell of the LTE cell.
wherein, dividing all candidate cells into high priority candidate cells and low priority candidate cells comprises:
ranking all candidate cells according to the cell quality indexes of the candidate cells, wherein the candidate cells with smaller cell quality indexes are ranked more front;
and taking N candidate cells with the top rank as the high-priority candidate cells, and taking the candidate cells except the high-priority candidate cells in all the candidate cells as the low-priority candidate cells.
In order to more clearly understand the present invention, the above-mentioned process is described in detail below by specific examples. The flow described in this embodiment is shown in fig. 3, and may include the following steps:
S201, the server obtains measurement statistical data of the base station and the user terminal. The measurement statistical data mainly includes the sampling level value of each cell, i.e., the sampling signal strength.
s202, generating each maximum fully-associated cell set of the whole network. For each cell, determining an associated cell of the cell, where the first threshold may be set to 12dB, and the second threshold is set to 1%, that is, the number of sampling points whose difference between the signal intensity of the cell and the signal intensities of multiple sampling points in a neighboring cell is less than 12dB, and the ratio of the number of sampling points in the neighboring cell to the number of all sampling points in the neighboring cell is greater than 1%, the neighboring cell is a cell having a mutual co-frequency interference relationship with the candidate cell, that is, the associated cell of the cell. And obtaining all maximum fully-associated cell sets in the whole area based on the same frequency interference relationship among the cells.
S203, taking each cell as a target cell, and calculating the cell quality index of the target cell. And calculating the cell quality index of the target cell according to a formula 4 according to the associated cell of the target cell in the maximum fully associated cell set.
S204, when the terminal of the LTE initiates the voice service, the server selects a candidate cell of the LTE cell where the terminal needing voice fallback is located. And searching all GSM cells within the range of 300m by taking the LTE cell as a center to serve as candidate cells of the LTE cell.
S205, distributing priorities for all candidate cells according to the cell quality indexes, and setting a first threshold and a second threshold of signal intensity. Ranking all candidate cells according to the cell quality index, setting 5 candidate cells at the top of the ranking as high priority, setting a first threshold as-100 dBm, setting the rest candidate cells at the bottom of the ranking as low priority, and setting a second threshold as-90 dBm.
s206, the server establishes a cell information list of the candidate cells and sends the cell information list to the terminal needing voice fallback, wherein the cell information list can comprise main frequency point information, priority indication and signal strength threshold of each candidate cell.
S207, the terminal reads cell information of all candidate cells and selects the voice fallback cell. The terminal preferentially measures the signal intensity of the high-priority candidate cell according to the sequence of the candidate cells, compares the signal intensity with a first threshold, and selects the high-priority candidate cell as a voice fallback cell if the signal intensity of the high-priority candidate cell is greater than the first threshold; if the signal intensity of the high-priority candidate cell is not greater than the first threshold, measuring the signal intensity of the low-priority candidate cell, and comparing the measured signal intensity with a second threshold; and if the candidate cells in the cell information list do not meet the conditions, the terminal searches other cell frequency points and falls back by self.
Based on the same technical concept, an embodiment of the present invention further provides a device for selecting a voice fallback cell, as shown in fig. 4, including:
A candidate cell module 1, configured to use a GSM cell having a distance to an LTE cell within a first range as a candidate cell for the LTE cell to fall back;
The associated cell module 2 is used for selecting a cell having a mutual co-channel interference relationship with the candidate cell as an associated cell of the candidate cell;
A parameter determining module 3, configured to determine a cell quality index of the candidate cell according to the number of carriers of the associated cell of the candidate cell, and the number of frequency points in the associated cell of the candidate cell that is the same as the number of frequency points in the candidate cell;
and the voice fallback module 4 is configured to select one candidate cell as the voice fallback cell of the LTE cell according to the cell quality index of each candidate cell.
the associated cell module 2 is further configured to:
Acquiring a cell with the distance to the candidate cell within a second range, and taking the cell as a neighboring cell of the candidate cell;
Acquiring the signal intensity of a plurality of sampling points of a neighboring cell of the candidate cell;
Determining the ratio of the number of sampling points of which the difference between the signal intensity of the candidate cell and the signal intensities of a plurality of sampling points in a neighboring cell of the candidate cell is less than a first threshold value to the number of all sampling points in the neighboring cell;
And if the ratio is larger than a second threshold value, the adjacent cell is a cell which has a mutual co-channel interference relationship with the candidate cell.
the parameter determining module 3 is further configured to:
determining the cell carrier index of the candidate cell according to the sum of the carrier numbers of all the associated cells of the candidate cell;
determining the cell co-frequency index of the candidate cell according to the sum of the same number of the frequency points of all the associated cells of the candidate cell and the frequency points of the candidate cell;
and determining the cell quality index of the candidate cell according to the cell carrier index and the cell co-frequency index of the candidate cell.
the cell quality index of the candidate cell satisfies the following formula:
Cell quality index ═ a1x cell carrier index + a2X cell co-frequency index;
wherein, a1A weighting factor being the cell carrier index, a2And the weighting coefficient is the same frequency index of the cell.
The voice fallback module 4 is further configured to:
dividing all candidate cells into high-priority candidate cells and low-priority candidate cells according to the cell quality index of each candidate cell;
acquiring the signal strength of the main signal of each candidate cell;
Comparing the signal strength of the main signal of each high-priority candidate cell with a first threshold value, and selecting the high-priority candidate cell of which the signal strength of the main signal is greater than the first threshold value;
comparing the signal strength of the main signal of each low-priority candidate cell with a second threshold value, and selecting the low-priority candidate cell of which the signal strength of the main signal is greater than the second threshold value;
And selecting the candidate cell with the minimum cell quality index as the voice fallback cell of the LTE cell from the high-priority candidate cell with the signal strength of the main signal larger than the first threshold and the low-priority candidate cell with the signal strength of the main signal larger than the second threshold.
The voice fallback module 4 is further configured to:
Ranking all candidate cells according to the cell quality indexes of the candidate cells, wherein the candidate cells with smaller cell quality indexes are ranked more front;
And taking N candidate cells with the top rank as the high-priority candidate cells, and taking the candidate cells except the high-priority candidate cells in all the candidate cells as the low-priority candidate cells.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
these computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (10)
1. A method for selecting a voice fallback cell, comprising:
Taking a global system for mobile communications (GSM) cell with a distance to a Long Term Evolution (LTE) cell within a first range as a candidate cell for the LTE cell voice fallback;
Selecting a cell having a mutual co-channel interference relationship with a candidate cell as an associated cell of the candidate cell;
determining the cell carrier index of the candidate cell according to the sum of the carrier numbers of all the associated cells of the candidate cell;
Determining the cell co-frequency index of the candidate cell according to the sum of the same number of the frequency points of all the associated cells of the candidate cell and the frequency points of the candidate cell;
determining the cell quality index of the candidate cell according to the cell carrier index and the cell co-frequency index of the candidate cell;
And selecting one candidate cell as the voice fallback cell of the LTE cell according to the cell quality index of each candidate cell.
2. the method of claim 1, wherein the selecting a cell having a co-channel interference relationship with a candidate cell as an associated cell of the candidate cell comprises:
acquiring a cell with the distance to the candidate cell within a second range, and taking the cell as a neighboring cell of the candidate cell;
acquiring the signal intensity of a plurality of sampling points of a neighboring cell of the candidate cell;
Determining the ratio of the number of sampling points of which the difference between the signal intensity of the candidate cell and the signal intensities of a plurality of sampling points in a neighboring cell of the candidate cell is less than a first threshold value to the number of all sampling points in the neighboring cell;
And if the ratio is larger than a second threshold value, the adjacent cell is a cell which has a mutual co-channel interference relationship with the candidate cell.
3. the method of claim 1, wherein the cell quality index of the candidate cell satisfies the following formula:
cell quality index ═ a1X cell carrier index + a2X cell co-frequency index;
Wherein, a1A weighting factor being the cell carrier index, a2And the weighting coefficient is the same frequency index of the cell.
4. the method of claim 1, wherein the selecting one candidate cell as the voice fallback cell for the LTE cell according to the cell quality index of each candidate cell comprises:
Dividing all candidate cells into high-priority candidate cells and low-priority candidate cells according to the cell quality index of each candidate cell;
acquiring the signal strength of the main signal of each candidate cell;
Comparing the signal strength of the main signal of each high-priority candidate cell with a first threshold value, and selecting the high-priority candidate cell of which the signal strength of the main signal is greater than the first threshold value;
Comparing the signal strength of the main signal of each low-priority candidate cell with a second threshold value, and selecting the low-priority candidate cell of which the signal strength of the main signal is greater than the second threshold value;
And selecting the candidate cell with the minimum cell quality index as the voice fallback cell of the LTE cell from the high-priority candidate cell with the signal strength of the main signal larger than the first threshold and the low-priority candidate cell with the signal strength of the main signal larger than the second threshold.
5. the method of claim 4, wherein the dividing all candidate cells into high priority candidate cells and low priority candidate cells according to the cell quality index of each candidate cell comprises:
ranking all candidate cells according to the cell quality indexes of the candidate cells, wherein the candidate cells with smaller cell quality indexes are ranked more front;
and taking N candidate cells with the top rank as the high-priority candidate cells, and taking the candidate cells except the high-priority candidate cells in all the candidate cells as the low-priority candidate cells.
6. an apparatus for selecting a voice fallback cell, comprising:
the candidate cell module is used for taking a GSM cell with a distance to an LTE cell within a first range as a candidate cell for the LTE cell to fall back;
The associated cell module is used for selecting a cell which has a mutual co-channel interference relationship with the candidate cell as an associated cell of the candidate cell;
a parameter determining module, configured to determine a cell carrier index of the candidate cell according to a sum of carrier numbers of all associated cells of the candidate cell; determining the cell co-frequency index of the candidate cell according to the sum of the same number of the frequency points of all the associated cells of the candidate cell and the frequency points of the candidate cell; determining the cell quality index of the candidate cell according to the cell carrier index and the cell co-frequency index of the candidate cell;
And the voice fallback module is used for selecting one candidate cell as the voice fallback cell of the LTE cell according to the cell quality index of each candidate cell.
7. the apparatus of claim 6, wherein the associated cell module is further configured to:
acquiring a cell with the distance to the candidate cell within a second range, and taking the cell as a neighboring cell of the candidate cell;
acquiring the signal intensity of a plurality of sampling points of a neighboring cell of the candidate cell;
determining the ratio of the number of sampling points of which the difference between the signal intensity of the candidate cell and the signal intensities of a plurality of sampling points in a neighboring cell of the candidate cell is less than a first threshold value to the number of all sampling points in the neighboring cell;
and if the ratio is larger than a second threshold value, the adjacent cell is a cell which has a mutual co-channel interference relationship with the candidate cell.
8. The apparatus of claim 6, wherein the cell quality index of the candidate cell satisfies the following formula:
Cell quality index ═ a1X cell carrier index + a2x cell common frequency fingercounting;
wherein, a1a weighting factor being the cell carrier index, a2And the weighting coefficient is the same frequency index of the cell.
9. The apparatus of claim 6, wherein the voice fallback module is further configured to:
dividing all candidate cells into high-priority candidate cells and low-priority candidate cells according to the cell quality index of each candidate cell;
Acquiring the signal strength of the main signal of each candidate cell;
Comparing the signal strength of the main signal of each high-priority candidate cell with a first threshold value, and selecting the high-priority candidate cell of which the signal strength of the main signal is greater than the first threshold value;
Comparing the signal strength of the main signal of each low-priority candidate cell with a second threshold value, and selecting the low-priority candidate cell of which the signal strength of the main signal is greater than the second threshold value;
and selecting the candidate cell with the minimum cell quality index as the voice fallback cell of the LTE cell from the high-priority candidate cell with the signal strength of the main signal larger than the first threshold and the low-priority candidate cell with the signal strength of the main signal larger than the second threshold.
10. the apparatus of claim 9, wherein the voice fallback module is further configured to:
Ranking all candidate cells according to the cell quality indexes of the candidate cells, wherein the candidate cells with smaller cell quality indexes are ranked more front;
And taking N candidate cells with the top rank as the high-priority candidate cells, and taking the candidate cells except the high-priority candidate cells in all the candidate cells as the low-priority candidate cells.
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| WO2019061424A1 (en) * | 2017-09-30 | 2019-04-04 | 深圳市云中飞网络科技有限公司 | Csfb fall-back result detecting method and device, and computer storage medium |
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| CN113950114B (en) * | 2021-10-21 | 2023-08-11 | 中国联合网络通信集团有限公司 | Blind redirection fallback method, base station, terminal and network system |
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| CN1722889A (en) * | 2004-07-15 | 2006-01-18 | 中兴通讯股份有限公司 | A method for realizing multi-carrier frequency coverage of TD-SCDMA system |
| WO2009073343A1 (en) * | 2007-12-03 | 2009-06-11 | Motorola, Inc. | Frequency planning for a cellular communication system |
| CN102970696A (en) * | 2012-12-14 | 2013-03-13 | 上海大唐移动通信设备有限公司 | Frequency optimization method for communication system |
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| CN1722889A (en) * | 2004-07-15 | 2006-01-18 | 中兴通讯股份有限公司 | A method for realizing multi-carrier frequency coverage of TD-SCDMA system |
| WO2009073343A1 (en) * | 2007-12-03 | 2009-06-11 | Motorola, Inc. | Frequency planning for a cellular communication system |
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