CN107592644B - Circuit domain fallback method, base station and terminal - Google Patents
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Abstract
The invention provides a circuit domain fallback method, a base station and a terminal, wherein a delay decision timer is additionally arranged at the base station side, the base station starts the delay decision timer when receiving a first measurement report, and after the delay decision timer counts to reach preset time, the base station acquires different system frequency points with the strongest signal strength according to all the received measurement reports and sends the different system frequency points with the strongest signal strength to the terminal, so that the terminal can fall to the different system frequency points with the strongest signal strength to initiate a voice service request, the success rate of circuit domain fallback is improved, a fallback indication cannot be sent to the terminal only according to the first measurement report, the randomness of the terminal when selecting the first different system frequency point when measuring the signal strength is avoided, the fallback failure caused by the fall of the terminal with the different system frequency points with weaker signals is avoided, and CSFB call delay is not excessively increased, user perception is guaranteed.
Description
Technical Field
The present invention relates to the field of communications technologies, and in particular, to a circuit switched fallback method, a base station, and a terminal.
Background
An LTE (Long Term Evolution ) network designed based on packet domain full IP cannot bear traditional circuit domain Voice service, and a target scheme for bearing Voice is based on a Voice Over internet protocol (VoIP) scheme of an IMS (IP Multimedia Subsystem). However, before the VoLTE industry matures and the LTE network is conditioned, it is still necessary to use a 2G/3G network to carry voice, i.e. a CSFB (Circuit Switched Fallback) scheme is adopted to directly utilize 2/3G network to provide voice service. The basic idea of the CSFB scheme is that when the terminal resides in an idle state or a data service connection state of the LTE network, and there is a voice service requirement (a calling party or a called party), the terminal falls back to the 2/3G network to establish a voice service with the assistance of the LTE network, and then returns to the LTE network quickly after the call is completed. In general, there are two main circuit domain fallback strategies for CSFB, namely blind redirection (i.e. RRC redirection), measurement-based redirection.
The blind redirection fallback strategy is that when the terminal initiates a voice service requirement in the LTE network, the LTE network issues an RRCRelease message, and the message carries information of a fallback target network 2/3G frequency point to guide the terminal to fall back. After receiving the message, the terminal searches for a suitable cell according to the designated frequency point and reads the broadcast message, and establishes the CS voice service in the 2G or 3G current network flow. Based on the measurement redirection fallback strategy, on the basis of RRC redirection, 2/3G inter-system neighbor cells are configured on a network side, measurement configuration information is informed to a terminal through an RRCConnection Reconfiguration message, the terminal starts to measure 2/3G neighbor cells according to the measurement configuration after receiving the measurement configuration information and reports a B1 event measurement report, and an LTE network sends 2/3G frequency point information of a target network to an RRC Release message according to the measurement report to guide the terminal to fall back.
The existing two circuit switched fallback strategies both have the probabilistic CSFB failure or call drop, so that the CS voice service cannot be completed normally, resulting in more complaints of 4G users and poor user experience.
Disclosure of Invention
The invention provides a circuit switched fallback method, a base station and a terminal, which aim to improve the success rate of circuit switched fallback, meet the requirement of a user on normally completing a CS voice service and improve user experience.
One aspect of the present invention provides a circuit switched fallback method, including:
a base station receives a circuit switched fallback service request sent by a terminal and sends an inter-system frequency point measurement control message to the terminal, wherein the inter-system frequency point measurement control message comprises an inter-system frequency point to be detected;
the base station sequentially receives a measurement report reported by the terminal after the terminal measures the signal strength of each different system frequency point;
the base station starts a delay decision timer when receiving a first measurement report, and after the delay decision timer reaches preset time, the base station acquires the different system frequency point with the strongest signal intensity according to all the received measurement reports;
and the base station sends the different system frequency point with the strongest signal strength to the terminal so that the terminal falls back to the different system frequency point with the strongest signal strength to initiate a voice service request.
Another aspect of the present invention provides a circuit domain fallback method, including:
the terminal sends a circuit switched fallback service request to the base station;
the terminal receives a different system frequency point measurement control message sent by the base station, wherein the different system frequency point measurement control message comprises a different system frequency point to be detected;
the terminal generates a measurement report for measuring the signal intensity of any one of the inter-system frequency points and reports the measurement report to the base station in sequence;
the terminal receives the inter-system frequency point with the strongest signal intensity sent by the base station after the delay decision timer reaches the preset time;
and the terminal falls back to the different system frequency point with the strongest signal intensity to initiate a voice service request.
Another aspect of the present invention provides a base station, including:
the first transceiving module is used for receiving a circuit switched fallback service request sent by a terminal and sending an inter-system frequency point measurement control message to the terminal, wherein the inter-system frequency point measurement control message comprises an inter-system frequency point to be detected;
the first transceiver module is further configured to sequentially receive a measurement report reported by the terminal after the terminal measures the signal strength of each inter-system frequency point;
the processing module is used for starting a delay decision timer when a first measurement report is received, and after the delay decision timer reaches preset time, the base station acquires the different system frequency points with the strongest signal intensity according to all the received measurement reports;
the first transceiver module is further configured to send the inter-system frequency point with the strongest signal strength to the terminal, so that the terminal falls back to the inter-system frequency point with the strongest signal strength to initiate a voice service request.
Another aspect of the present invention provides a terminal, including:
the second transceiver module is used for sending a circuit switched fallback service request to the base station; receiving a different system frequency point measurement control message sent by the base station, wherein the different system frequency point measurement control message comprises a different system frequency point to be detected;
the measurement module is used for generating a measurement report for the signal strength measured by any one of the different system frequency points, and the measurement report is sequentially reported to the base station by the second transceiver module;
the second transceiver module is further configured to receive the inter-system frequency point with the strongest signal strength, which is sent by the base station after the delay decision timer reaches a preset time;
and the fallback module is used for fallback to the different system frequency point with the strongest signal strength to initiate a voice service request.
The circuit domain fallback method, the base station and the terminal provided by the invention have the advantages that the delay decision timer is additionally arranged at the base station side, the base station starts the delay decision timer when receiving the first measurement report, after the delay decision timer counts the time to reach the preset time, the base station acquires the different system frequency points with the strongest signal strength according to all the received measurement reports and sends the different system frequency points with the strongest signal strength to the terminal, so that the terminal can fall to the different system frequency points with the strongest signal strength to initiate a voice service request, the success rate of circuit domain fallback is improved, a fallback indication cannot be sent to the terminal only according to the first measurement report, the randomness of the terminal in selecting the first different system frequency point when the terminal measures the signal strength is avoided, the fallback failure caused by the fall of the different system frequency points with weaker signals by the terminal is avoided, and the CSFB call delay is not excessively increased, user perception is guaranteed.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic diagram of a test scenario of the present invention;
FIG. 2 is a communication signaling for testing a test point 3 by using a measurement redirection-based strategy according to the present invention;
fig. 3 is a flowchart of a circuit switched fallback method according to an embodiment of the present invention;
fig. 4 is a flowchart of a circuit domain fallback method according to a second embodiment of the present invention;
fig. 5 is a flowchart of a circuit switched fallback method according to a third embodiment of the present invention;
fig. 6 is a structural diagram of a base station according to a fourth embodiment of the present invention;
fig. 7 is a structural diagram of a terminal according to a fifth embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and 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.
Aiming at the problem that CSFB failure or call drop condition can probabilistically occur in the existing two circuit domain fall-back strategies, the two circuit domain fall-back strategies are tested and verified.
At present, the universal mobile telecommunication system UMTS2100 adopts a macro-micro station different frequency networking framework, and a UMTS900 system is introduced to improve the signal strength in a core urban area in order to solve the problem of deep coverage. In the UMTS900 contiguous coverage area, the UMTS network changes from 2-frequency-point main coverage to 3-frequency-point main coverage: UMTS2100 outdoor frequency point, UMTS2100 indoor frequency division point, UMTS900 deep coverage frequency point, each scene overlapping coverage.
The test scenario is shown in fig. 1. When a terminal (UE) moves from a coverage area with a 3G/4G macro station to a coverage area with only a 3G room branch, a weaker 4G macro station signal exists in the edge area covered by the 3G room branch, and the terminal preferentially resides in a 4G network. Since the UMTS900 deep coverage bin is not detected in this scenario, this bin is ignored. Respectively carrying out 10 times of calling and called voice tests on the 4 test points according to blind redirection and measurement redirection, configuring 10713 fallback frequency points for the blind redirection by the base station, and carrying out measurement redirection on the scene: configuring 10713 and 10663 two fallback frequency points, and increasing the adjacent cell relation of the cells corresponding to the two frequency points. The specific parameter strategy and test results are shown in table 1.
TABLE 1
For blind redirection, as a 3G macro station 10713 is configured with a fallback frequency point, the terminal can directly fall back to a target frequency point 10713 at test points 1 and 2 with stronger signals of the 3G macro station, so that the voice service quality can be met, and the CSFB success rate can reach 100%; for the test point 4, as no 3G room frequency division signal exists, the terminal searches for an available frequency point by itself at the moment, and the 3G room frequency division point 10663 exists at the moment, so that the test point can be successfully fallen back; for the test point 3, because the signal strength of the target frequency point 10713 is weak (-100dbm to-110 dbm), although the frequency division point signal of the 3G room is strong, the terminal still falls back at the frequency point 10713 according to the RRCConnectionRelease message, so that a call drop phenomenon exists at a certain probability, and CSFB is unstable.
And the base station transmits a 3G adjacent cell of the measurement report through an RRC connectionRelease message to indicate that the terminal falls back to a target frequency point to initiate voice service establishment.
a) Test points 1 and 4: due to the adoption of a measurement-based redirection strategy, the terminal can accurately and effectively report to the network side according to the measured frequency point signal intensity, and the CSFB success rate reaches 100 percent.
b) Test point 2: when the signals of the 10713 frequency point and the 10663 frequency point of the 3G macro station are good (-75dbm to-95 dbm), the terminal reports the measured signal intensity to the network side, and the radio environment of the signal falling to the target frequency point basically can meet the voice service quality, so that the success rate of the CSFB is all 100 percent.
c) Test point 3: under the coverage of the LTE macro station, due to the fact that signals of the 3G macro station are weak (-100dbm to-110 dbm), signals of the 3G room are strong (-70dbm to-90 dbm), the terminal can randomly fall back to a 10713 frequency point with weak signals to initiate voice services, and disconnection and call drop events are caused.
Fig. 2 shows a communication signaling for testing a test point 3 by using a measurement redirection policy, and it is found through signaling analysis that a terminal only reports a measurement report of one frequency point at a time, where the measured signal strength is RSCP (Received signal code Power), that is, a level value of the signal strength, and the terminal does not report a measurement report of a frequency point with a strongest RSCP signal preferentially, and reports measurement reports of other UMTS frequency points in a next GAP period (the GAP period of a test area is set to 40 milliseconds) after reporting a first UMTS measurement report. The two measurement report resolutions are shown in table 2.
TABLE 2
Because the 3GPP protocol does not specify the restriction on how the terminal reports the measurement report of the different system when the CSFB service is performed, the base station will immediately perform redirection decision after receiving the first measurement report, so that after receiving the measurement report of the neighboring cell of the frequency point with a weaker signal 10713, the base station will immediately instruct the terminal to fall back to the target frequency point cell to establish the voice service, and will not wait for the measurement report of the neighboring cell of the frequency point 10663 with a better subsequent signal to perform delay decision, so that the terminal can perform CSFB fall back only at the frequency point with the weaker signal 10713 according to the instruction of the base station, thereby causing CSFB connection failure. That is, as long as a frequency point with a weak signal exists in the current environment of the terminal, the first measurement report that the terminal may just report is the measurement report for the frequency point, and a probabilistic CSFB on-failure may exist based on the measurement redirection policy.
Based on the test and verification results, the invention provides a circuit domain fallback method, a base station and a terminal, so as to improve the success rate of circuit domain fallback, meet the requirement of a user on normally completing a CS voice service and improve the user experience.
Example one
Fig. 3 is a flowchart of a circuit switched fallback method according to an embodiment of the present invention. As shown in fig. 3, the present invention provides a circuit switched fallback method, the main execution body of which is a base station, and the method specifically includes the following steps:
s101, a base station receives a circuit switched fallback service request sent by a terminal and sends an inter-system frequency point measurement control message to the terminal, wherein the inter-system frequency point measurement control message comprises an inter-system frequency point to be detected.
In this embodiment, when the terminal has a voice service requirement (a calling party or a called party), the terminal sends a circuit domain fallback service request to the base station (eNodeB), and the base station returns an inter-system frequency point measurement control message after receiving the circuit domain fallback service request, where the inter-system frequency point measurement control message may be an RRCConnectionReconfiguration message. Of course, before sending the inter-system frequency point measurement control message to the terminal, the base station needs to configure the inter-system frequency point for the terminal to fall back.
S102, the base station sequentially receives measurement reports reported by the terminal after the terminal measures the signal intensity of the different system frequency points.
In this embodiment, after receiving the control message for measuring the frequency point of the different system sent by the base station, the terminal sequentially measures the Signal strength of the frequency point of the different system to be measured included in the control message, where the measurement of the Signal strength may be measurement of RSCP (Received Signal Code Power), that is, a level value of the measured Signal strength. Because the terminal has only one receiver under normal conditions and receives signals on only one frequency point at the same time, when the different system frequency points are measured, the signal intensity of only one different system frequency point can be measured each time, and then a Measurement Report (MR) is generated and reported to the base station. In this embodiment, the sequence of measuring the signal strength for different system frequency points by the terminal may be random, and certainly, the sequence may also be specified.
Further, the step S102 of the base station sequentially receiving the measurement report reported by the terminal after measuring the signal strength of the different system frequency points includes:
and the base station receives the measurement report reported by the terminal in a measurement period, wherein the measurement report is generated by measuring the signal intensity of any different system frequency point by the terminal.
In this embodiment, in a GAP measurement period, a terminal performs signal strength measurement on a different system frequency point, and in a GAP measurement period, the terminal leaves the current frequency point to another frequency point to perform signal strength measurement, and reports a measurement report to a base station in the GAP measurement period, and in a next GAP measurement period, performs signal strength measurement on another different system frequency point and reports the measurement report to the base station, that is, the base station receives a measurement report reported by a terminal in a measurement period. The GAP period is usually 40 ms, but may be designed to have other time lengths according to the requirement.
S103, the base station starts a delay decision timer when receiving a first measurement report, and after the delay decision timer reaches preset time, the base station acquires the different system frequency point with the strongest signal strength according to all the received measurement reports.
In this embodiment, a delay decision timer is added at the base station side, and when receiving a first measurement report, the base station does not directly instruct the terminal to fall back according to the measurement report, but continues to wait for a measurement report subsequently reported by the terminal until the delay decision timer times to a preset time, and then obtains the inter-system frequency point with the strongest signal strength according to all the received measurement reports. Because the base station does not only make a decision according to the first measurement report, the randomness of the terminal in selecting the first different system frequency point when measuring the signal strength is avoided, and the fallback failure caused by the fallback of the terminal with the different system frequency point with weaker signal is avoided.
In this embodiment, the base station acquires the inter-system frequency points with the strongest signal strength according to all the received measurement reports, and specifically, the base station performs signal strength sequencing on all the currently received inter-system frequency points every time the base station receives one measurement report, and takes the inter-system frequency points with the strongest signal strength in the sequencing as final results until the delay decision timer times for a preset time; or when the delay decision timer reaches the preset time, the base station sequences the signal intensity of the different system frequency points in all the measurement reports, and the different system frequency point with the strongest signal intensity is taken as a final result.
In this embodiment, the preset time may be a measurement period N-1 times, where N is the number of types of the inter-system frequency points, where the types of the inter-system frequency points include at least two of an outdoor frequency point, a room frequency dividing point, and a deep coverage frequency point. It should be noted that the number of types of the inter-system frequency points is not the number of inter-system frequency points to be detected contained in the inter-system frequency point measurement control message, and there may be a case where the number of inter-system frequency points to be detected contained in the inter-system frequency point measurement control message is less than the type of the inter-system frequency points, for example, only one of the outdoor frequency points is present in a part of rural areas, and at this time, the terminal only detects the signal intensity of the outdoor frequency point, and sends a detection report, and the base station still needs to wait for the delay decision timer to time to reach the preset time and then make a decision.
Preferably, considering the universality of the system, the types of the different system frequency points can be set to be three types of currently and commonly used UMTS2100 outdoor frequency points, UMTS2100 room frequency dividing points and UMTS900 deep coverage, at this time, the preset time is a measurement period 2 times longer (for example, for measuring a GAP period of 40 milliseconds, the preset time is 80 milliseconds), that is, after receiving a first measurement report, timing is started, the measurement reports of the remaining two different system frequency points can be just received until the preset time is reached, and at this time, the different system frequency point with the strongest signal is obtained by judgment, so that the success rate of circuit domain fallback of the terminal can be ensured, the CSFB call delay is not excessively increased, and the user perception is ensured.
And S104, the base station sends the different system frequency point with the strongest signal strength to the terminal so that the terminal falls back to the different system frequency point with the strongest signal strength to initiate a voice service request.
In this embodiment, the base station sends the inter-system frequency point with the strongest signal strength to the terminal, and specifically, sends the inter-system frequency point with the strongest signal strength to the terminal through an RRCConnectionRelease message, and instructs the terminal to drop back to the inter-system frequency point with the strongest signal strength to initiate a voice service request, thereby implementing circuit switched fallback.
The circuit domain fallback method of the embodiment adds a delay decision timer at the base station side, the base station starts the delay decision timer when receiving a first measurement report, and after the delay decision timer reaches a preset time, the base station acquires the different system frequency points with the strongest signal strength according to all the received measurement reports and sends the different system frequency points with the strongest signal strength to the terminal, so that the terminal can fall back to the different system frequency points with the strongest signal strength to initiate a voice service request, thereby improving the success rate of circuit domain fallback, not sending a fallback indication to the terminal only according to the first measurement report, avoiding the randomness of the terminal selecting the first different system frequency point when measuring the signal strength, avoiding the fallback failure caused by the terminal falling back to the different system frequency points with weaker signals, and not excessively increasing CSFB call delay, user perception is guaranteed.
Example two
On the basis of the above embodiment, the inter-system frequency point measurement control message further includes a cell scrambling code corresponding to the inter-system frequency point.
In this embodiment, the base station carries, in the measurement control message of the different-system frequency point, not only the different-system frequency point to be measured, but also a cell scrambling code corresponding to the different-system frequency point, where the cell scrambling code is used to distinguish different cells of the one system frequency point, for example, the cell scrambling codes 266, 472, 473 under the frequency point 10713 and the cell scrambling code 25 under the frequency point 10663 in table 2.
Further, the step S102 of the base station sequentially receiving the measurement report reported by the terminal after measuring the signal strength of the different system frequency points includes:
and the base station sequentially receives measurement reports reported by the terminal after the terminal measures the signal intensity of different system frequency points, wherein each measurement report is obtained by the terminal measuring the signal intensity of the different system frequency point under a corresponding cell according to the cell scrambling code for any different system frequency point.
In this embodiment, when receiving the above-mentioned control message for measuring the frequency point of the different system, the terminal measures the signal strength of the frequency point of the different system for each frequency point of the different system, where for any different system, the signal strength of the frequency point of the different system in the cell corresponding to the cell scrambling code is measured, for example, for the frequency point 10713, the signal strength of the frequency point 10713 in the cell corresponding to the cell scrambling codes 266, 472, 473 are measured, and a measurement report is generated and reported to the base station. By measuring the signal strength of a plurality of cells, the measurement is more accurate, and the subsequent terminal falls back at the frequency point with the strongest signal strength. Certainly, the terminal is not limited to measuring the signal strength corresponding to the cell scrambling code carried in the inter-system frequency point measurement control message, and may additionally measure the signal strength of other cells and report the measured signal strength to the base station, so as to avoid missing the cell with a strong signal.
As shown in fig. 4, the step S103 of acquiring, by the base station according to all the received measurement reports, the inter-system frequency point with the strongest signal strength specifically includes:
s201, the base station acquires a cell with the strongest signal strength in each measurement report, and the signal strength of the cell is used as the signal strength of a different system frequency point corresponding to the measurement report;
s202, the base station acquires the different system frequency point with the strongest signal intensity according to the signal intensity of each different system frequency point.
In this embodiment, the strongest signal strength of the cell is used as the signal strength of the different-system frequency points to perform sequencing, so as to obtain the different-system frequency points with the strongest signal strength, which considers that the different-system frequency points which are finally returned to the terminal by the base station are only fallen back, and the terminal is also required to search the cell with the strongest signal under the different-system frequency points to initiate the voice service request, so that the signal strength of the cell with the strongest signal can replace the signal strength of the corresponding different-system frequency points, and thus the signal strengths of different systems have more practical comparability.
EXAMPLE III
Fig. 5 is a flowchart of a circuit switched fallback method according to a third embodiment of the present invention. As shown in fig. 5, the embodiment provides a circuit domain fallback method, where an execution main body is a terminal, and the method includes the following specific steps:
s301, the terminal sends a circuit switched fallback service request to the base station.
In this embodiment, the terminal may be a smart phone, a tablet computer with a communication function, or the like. When the terminal has a voice service requirement (calling party or called party), the terminal sends a circuit switched fallback service request to a base station (eNodeB).
S302, the terminal receives a different system frequency point measurement control message sent by the base station, wherein the different system frequency point measurement control message contains a different system frequency point to be detected.
In this embodiment, after receiving the cs fallback service request, the base station returns the inter-system frequency point measurement control message to the terminal, so as to instruct the terminal to measure the signal strength of the inter-system frequency point to be measured according to the inter-system frequency point measurement control message. Specifically, the inter-system frequency measurement control message may be an RRC ConnectionReconfiguration message.
And S303, the terminal generates a measurement report for measuring the signal intensity of any one of the different system frequency points and reports the measurement report to the base station in sequence.
In this embodiment, after receiving the control message for measuring the frequency point of the different system sent by the base station, the terminal sequentially measures the Signal strength of the frequency point of the different system to be measured included in the control message, where the measurement of the Signal strength may be measurement of RSCP (Received Signal Code Power), that is, a level value of the measured Signal strength. Because the terminal has only one receiver under normal conditions and receives signals on only one frequency point at the same time, when the different system frequency points are measured, the signal intensity of only one different system frequency point can be measured each time, and then a Measurement Report (MR) is generated and reported to the base station. In this embodiment, the sequence of measuring the signal strength for different system frequency points by the terminal may be random, and certainly, the sequence may also be specified.
Further, the terminal in S303 generates a measurement report for measuring the signal strength of any of the inter-system frequency points, and reports the measurement report to the base station in sequence, which specifically includes:
the terminal measures the signal intensity of any one of the inter-system frequency points in a measurement period to generate a measurement report;
and the terminal reports the measurement report to the base station.
In this embodiment, in a GAP measurement period, a terminal performs signal strength measurement on a different system frequency point, and in a GAP measurement period, the terminal leaves the current frequency point to another frequency point to perform signal strength measurement, and reports a measurement report to a base station in the GAP measurement period, and in a next GAP measurement period, performs signal strength measurement on another different system frequency point and reports the measurement report to the base station, that is, the base station receives a measurement report reported by a terminal in a measurement period. With a GAP period of typically 40 milliseconds.
Furthermore, the inter-system frequency point measurement control message may further include a cell scrambling code corresponding to the inter-system frequency point; the terminal generates a measurement report for the strength of the measurement signal of any one of the inter-system frequency points, which specifically includes:
and the terminal measures the signal intensity of the different system frequency point in the cell corresponding to the cell scrambling code according to the corresponding cell scrambling code and generates a measurement report.
For example, if the inter-system frequency point measurement control message carries the cell scrambling codes 266, 472, 473 at the frequency point 10713 and the cell scrambling code 25 at the frequency point 10663, the terminal measures the signal strength of the frequency point 10713 at the cells corresponding to the cell scrambling codes 266, 472, 473 when measuring the signal strength at the frequency point 10713, respectively, generates a measurement report, and reports the measurement report to the base station; when the signal intensity is measured at the frequency point 10663, the signal intensity of the frequency point 10663 in the cell corresponding to the cell scrambling code 25 is measured, and a measurement report is generated and reported to the base station. Certainly, the terminal is not limited to measuring the signal strength corresponding to the cell scrambling code carried in the inter-system frequency point measurement control message, and may additionally measure the signal strength of other cells and report the measured signal strength to the base station, so as to avoid missing the cell with a strong signal.
And S304, the terminal receives the different system frequency point with the strongest signal intensity sent by the base station after the delay decision timer reaches the preset time.
In this embodiment, after the delay decision timer at the base station side times for the preset time, the base station obtains the inter-system frequency point with the strongest signal strength according to all the received measurement reports, and sends the inter-system frequency point with the strongest signal strength to the terminal, that is, the base station does not only make a decision according to the first measurement report, thereby avoiding the randomness when the terminal selects the first inter-system frequency point when measuring the signal strength, and avoiding the fallback failure caused by the terminal dropping at the inter-system frequency point with a weaker signal. And the base station sends the different system frequency point with the strongest signal intensity to the terminal, and specifically sends the different system frequency point to the terminal through an RRCConnectionRelease message.
S305, the terminal falls back to the different system frequency point with the strongest signal intensity to initiate a voice service request.
In this embodiment, the terminal initiates a voice service request according to the inter-system frequency point with the strongest signal strength, specifically, searches for a cell with the strongest signal at the inter-system frequency point, and establishes a voice service through the cell, thereby implementing circuit switched fallback.
In the circuit switched fallback method of the embodiment, a terminal sends a circuit switched fallback service request to a base station, receives a measurement control message of a different system frequency point sent by the base station, generates a measurement report for any different system frequency point measurement signal strength according to the measurement control message of the different system frequency point, sequentially reports the measurement report to the base station, receives the different system frequency point with the strongest signal strength sent by the base station after a delay decision timer reaches a preset time, and finally falls to the different system frequency point with the strongest signal strength to initiate a voice service request. A delay decision timer is added on the base station side, the base station starts the delay decision timer when receiving a first measurement report, and after the delay decision timer counts the time to reach the preset time, the base station acquires the different system frequency points with the strongest signal strength according to all the received measurement reports and sends the different system frequency points with the strongest signal strength to the terminal, so that the terminal falls back to the different system frequency points with the strongest signal strength to initiate a voice service request, the success rate of circuit domain fall back is improved, the fall back indication cannot be sent to the terminal only according to the first measurement report, the randomness of the terminal when selecting the first different system frequency point when measuring the signal strength is avoided, the fall back failure caused by the fall back of the different system frequency points with weaker signals by the terminal is avoided, the CSFB call delay is not excessively increased, and the user perception is ensured.
Example four
Fig. 6 is a structural diagram of a base station according to a fourth embodiment of the present invention. The base station provided in this embodiment may execute the processing flows provided in the first and second embodiments of the circuit switched fallback method, as shown in fig. 6, the base station of this embodiment includes:
the first transceiving module is used for receiving a circuit switched fallback service request sent by a terminal and sending an inter-system frequency point measurement control message to the terminal, wherein the inter-system frequency point measurement control message comprises an inter-system frequency point to be detected;
the first transceiver module is further configured to sequentially receive a measurement report reported by the terminal after the terminal measures the signal strength of each inter-system frequency point;
the processing module is used for starting a delay decision timer when a first measurement report is received, and after the delay decision timer reaches preset time, the base station acquires the different system frequency points with the strongest signal intensity according to all the received measurement reports;
the first transceiver module is further configured to send the inter-system frequency point with the strongest signal strength to the terminal, so that the terminal falls back to the inter-system frequency point with the strongest signal strength to initiate a voice service request.
Further, the inter-system frequency point measurement control message may further include a cell scrambling code corresponding to the inter-system frequency point;
the first transceiver module may be specifically configured to:
sequentially receiving measurement reports reported by the terminal after the terminal measures the signal intensity of different system frequency points, wherein each measurement report is obtained by the terminal measuring the signal intensity of the different system frequency point under a corresponding cell according to the cell scrambling code for any different system frequency point;
the processing module is specifically operable to:
acquiring a cell with the strongest signal strength in each measurement report, and taking the signal strength of the cell as the signal strength of the different system frequency point corresponding to the measurement report;
and acquiring the different system frequency point with the strongest signal intensity according to the signal intensity of each different system frequency point.
Further, the first transceiver module may be specifically configured to:
receiving the measurement report reported by the terminal in a measurement period, wherein the measurement report is generated by measuring the signal strength of any different system frequency point by the terminal;
the preset time is N-1 times of the measurement period, and N is the number of the types of the different system frequency points, wherein the types of the different system frequency points comprise at least two of outdoor frequency points, indoor frequency points and deep coverage frequency points.
The base station provided in the embodiment of the present invention may be specifically configured to execute the method embodiments provided in fig. 3 and fig. 4, and specific functions are not described herein again.
In the base station of this embodiment, a delay decision timer is added at the base station side, and the base station starts the delay decision timer when receiving the first measurement report, when the time of the delay decision timer reaches the preset time, the base station acquires the different system frequency point with the strongest signal strength according to all the received measurement reports and sends the different system frequency point with the strongest signal strength to the terminal, so that the terminal can drop to the different system frequency point with the strongest signal strength to initiate the voice service request, the success rate of the circuit domain drop is improved, the drop indication can not be sent to the terminal only according to the first measurement report, the randomness of the terminal selecting the first different system frequency point when measuring the signal strength is avoided, therefore, the fallback failure caused by the fallback of the terminal at the frequency point of the different system with a weaker signal is avoided, the CSFB call delay is not excessively increased, and the user perception is guaranteed.
EXAMPLE five
Fig. 7 is a structural diagram of a terminal according to a fifth embodiment of the present invention. The terminal provided in this embodiment may execute the processing flows provided in the third and fourth embodiments of the circuit domain fallback method, as shown in fig. 7, the terminal of this embodiment includes:
the second transceiver module is used for sending a circuit switched fallback service request to the base station; receiving a different system frequency point measurement control message sent by the base station, wherein the different system frequency point measurement control message comprises a different system frequency point to be detected;
the measurement module is used for generating a measurement report for the signal strength measured by any one of the different system frequency points, and the measurement report is sequentially reported to the base station by the second transceiver module;
the second transceiver module is further configured to receive the inter-system frequency point with the strongest signal strength, which is sent by the base station after the delay decision timer reaches a preset time;
and the fallback module is used for fallback to the different system frequency point with the strongest signal strength to initiate a voice service request.
Further, the inter-system frequency point measurement control message may further include a cell scrambling code corresponding to the inter-system frequency point;
the measurement module is specifically operable to:
and for any one different system frequency point, measuring the signal intensity of the different system frequency point in the cell corresponding to the cell scrambling code according to the corresponding cell scrambling code, and generating a measurement report.
Further, the measurement module may be specifically configured to:
and measuring the signal intensity of any one of the inter-system frequency points in a measurement period to generate a measurement report, and driving the second transceiver module to report the measurement report to the base station.
The terminal provided in the embodiment of the present invention may be specifically configured to execute the method embodiment provided in fig. 5, and specific functions are not described herein again.
In the terminal of this embodiment, a circuit switched fallback service request is sent to a base station, and a measurement control message of a different system frequency point sent by the base station is received, a measurement report is generated for any different system frequency point measurement signal strength according to the measurement control message of the different system frequency point, and is sequentially reported to the base station, and the different system frequency point with the strongest signal strength sent by the base station after a delay decision timer reaches a preset time is received, and finally the different system frequency point with the strongest signal strength is dropped to initiate a voice service request. A delay decision timer is added on the base station side, the base station starts the delay decision timer when receiving a first measurement report, and after the delay decision timer counts the time to reach the preset time, the base station acquires the different system frequency points with the strongest signal strength according to all the received measurement reports and sends the different system frequency points with the strongest signal strength to the terminal, so that the terminal falls back to the different system frequency points with the strongest signal strength to initiate a voice service request, the success rate of circuit domain fall back is improved, the fall back indication cannot be sent to the terminal only according to the first measurement report, the randomness of the terminal when selecting the first different system frequency point when measuring the signal strength is avoided, the fall back failure caused by the fall back of the different system frequency points with weaker signals by the terminal is avoided, the CSFB call delay is not excessively increased, and the user perception is ensured.
In the embodiments provided in the present invention, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, or in a form of hardware plus a software functional unit.
The integrated unit implemented in the form of a software functional unit may be stored in a computer readable storage medium. The software functional unit is stored in a storage medium and includes several instructions to enable a computer device (which may be a personal computer, a server, or a network device) or a processor (processor) to execute some steps of the methods according to the embodiments of the present invention. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.
It is obvious to those skilled in the art that, for convenience and simplicity of description, the foregoing division of the functional modules is merely used as an example, and in practical applications, the above function distribution may be performed by different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules to perform all or part of the above described functions. For the specific working process of the device described above, reference may be made to the corresponding process in the foregoing method embodiment, which is not described herein again.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (8)
1. A circuit switched fallback method, comprising:
a base station receives a circuit switched fallback service request sent by a terminal and sends an inter-system frequency point measurement control message to the terminal, wherein the inter-system frequency point measurement control message comprises an inter-system frequency point to be detected;
the base station sequentially receives a measurement report reported by the terminal after the terminal measures the signal strength of each different system frequency point;
the base station starts a delay decision timer when receiving a first measurement report, and after the delay decision timer reaches preset time, the base station acquires the different system frequency point with the strongest signal intensity according to all the received measurement reports;
the base station sends the different system frequency point with the strongest signal strength to the terminal so that the terminal falls back to the different system frequency point with the strongest signal strength to initiate a voice service request;
the inter-system frequency point measurement control message also comprises a cell scrambling code corresponding to the inter-system frequency point;
the base station sequentially receives measurement reports reported by the terminal after measuring the signal strength of different system frequency points, and the method specifically comprises the following steps:
the base station sequentially receives measurement reports reported by the terminal after the terminal measures the signal intensity of different system frequency points, wherein each measurement report is obtained by the terminal measuring the signal intensity of the different system frequency point under a corresponding cell according to the cell scrambling code for any different system frequency point;
the base station acquires the inter-system frequency point with the strongest signal strength according to all the received measurement reports, and the method specifically comprises the following steps:
the base station acquires a cell with the strongest signal intensity in each measurement report, and takes the signal intensity of the cell as the signal intensity of the different system frequency point corresponding to the measurement report;
and the base station acquires the different system frequency point with the strongest signal intensity according to the signal intensity of each different system frequency point.
2. The method according to claim 1, wherein the base station sequentially receives measurement reports reported by the terminal after measuring signal strengths of different system frequency points, and specifically comprises:
the base station receives the measurement report reported by the terminal in a measurement period, wherein the measurement report is generated by measuring the signal intensity of any different system frequency point by the terminal;
the preset time is N-1 times of the measurement period, and N is the number of the types of the different system frequency points, wherein the types of the different system frequency points comprise at least two of outdoor frequency points, indoor frequency points and deep coverage frequency points.
3. A circuit switched fallback method, comprising:
the terminal sends a circuit switched fallback service request to the base station;
the terminal receives a different system frequency point measurement control message sent by the base station, wherein the different system frequency point measurement control message comprises a different system frequency point to be detected;
the terminal generates a measurement report for measuring the signal intensity of any one of the inter-system frequency points and reports the measurement report to the base station in sequence;
the terminal receives the inter-system frequency point with the strongest signal intensity sent by the base station after the delay decision timer reaches the preset time;
the terminal falls back to the different system frequency point with the strongest signal intensity to initiate a voice service request;
the inter-system frequency point measurement control message also comprises a cell scrambling code corresponding to the inter-system frequency point;
the terminal generates a measurement report for the strength of the measurement signal of any one of the inter-system frequency points, and the method specifically comprises the following steps:
and the terminal measures the signal intensity of the different system frequency point in the cell corresponding to the cell scrambling code according to the corresponding cell scrambling code and generates a measurement report.
4. The method according to claim 3, wherein the terminal generates a measurement report for measuring signal strength of any of the inter-system frequency points, and sequentially reports the measurement report to the base station, and specifically includes:
the terminal measures the signal intensity of any one of the inter-system frequency points in a measurement period to generate a measurement report;
and the terminal reports the measurement report to the base station.
5. A base station, comprising:
the first transceiving module is used for receiving a circuit switched fallback service request sent by a terminal and sending an inter-system frequency point measurement control message to the terminal, wherein the inter-system frequency point measurement control message comprises an inter-system frequency point to be detected;
the first transceiver module is further configured to sequentially receive a measurement report reported by the terminal after the terminal measures the signal strength of each inter-system frequency point;
the processing module is used for starting a delay decision timer when a first measurement report is received, and after the delay decision timer reaches preset time, the base station acquires the different system frequency points with the strongest signal intensity according to all the received measurement reports;
the first transceiver module is further configured to send the inter-system frequency point with the strongest signal strength to the terminal, so that the terminal falls back to the inter-system frequency point with the strongest signal strength to initiate a voice service request;
the inter-system frequency point measurement control message also comprises a cell scrambling code corresponding to the inter-system frequency point;
the first transceiver module is specifically configured to:
sequentially receiving measurement reports reported by the terminal after the terminal measures the signal intensity of different system frequency points, wherein each measurement report is obtained by the terminal measuring the signal intensity of the different system frequency point under a corresponding cell according to the cell scrambling code for any different system frequency point;
the processing module is specifically configured to:
acquiring a cell with the strongest signal strength in each measurement report, and taking the signal strength of the cell as the signal strength of the different system frequency point corresponding to the measurement report;
and acquiring the different system frequency point with the strongest signal intensity according to the signal intensity of each different system frequency point.
6. The base station of claim 5, wherein the first transceiver module is specifically configured to:
receiving the measurement report reported by the terminal in a measurement period, wherein the measurement report is generated by measuring the signal strength of any different system frequency point by the terminal;
the preset time is N-1 times of the measurement period, and N is the number of the types of the different system frequency points, wherein the types of the different system frequency points comprise at least two of outdoor frequency points, indoor frequency points and deep coverage frequency points.
7. A terminal, comprising:
the second transceiver module is used for sending a circuit switched fallback service request to the base station; receiving a different system frequency point measurement control message sent by the base station, wherein the different system frequency point measurement control message comprises a different system frequency point to be detected;
the measurement module is used for generating a measurement report for the signal strength measured by any one of the different system frequency points, and the measurement report is sequentially reported to the base station by the second transceiver module;
the second transceiver module is further configured to receive the inter-system frequency point with the strongest signal strength, which is sent by the base station after the delay decision timer reaches a preset time;
the fallback module is used for fallback to the different system frequency point with the strongest signal strength to initiate a voice service request;
the inter-system frequency point measurement control message also comprises a cell scrambling code corresponding to the inter-system frequency point;
the measurement module is specifically configured to:
and for any one different system frequency point, measuring the signal intensity of the different system frequency point in the cell corresponding to the cell scrambling code according to the corresponding cell scrambling code, and generating a measurement report.
8. The terminal of claim 7, wherein the measurement module is specifically configured to:
and measuring the signal intensity of any one of the inter-system frequency points in a measurement period to generate a measurement report, and driving the second transceiver module to report the measurement report to the base station.
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| CN108200096A (en) * | 2018-02-13 | 2018-06-22 | 广西英伦信息技术股份有限公司 | A kind of implementation method by LTE carrying voice calls |
| CN110881193B (en) * | 2018-09-05 | 2023-05-05 | 中国移动通信有限公司研究院 | Measurement method, terminal and network equipment for voice call-in and call-out |
| CN110267319B (en) * | 2019-07-17 | 2021-07-20 | 中国联合网络通信集团有限公司 | LTE network returning method based on position, mobile terminal and system |
| CN110392391B (en) * | 2019-07-23 | 2022-10-11 | 中国联合网络通信集团有限公司 | Cell fallback method and terminal equipment |
| CN113498123B (en) * | 2020-03-20 | 2023-06-02 | 华为技术有限公司 | Network access system, method and terminal |
| CN115250441B (en) * | 2021-04-28 | 2023-08-15 | 中国移动通信集团河北有限公司 | Method, device, equipment and medium for determining voice fallback time delay information |
| 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 |
| CN114727346A (en) * | 2022-03-31 | 2022-07-08 | 联想(北京)有限公司 | Method and device for redirecting different systems and electronic equipment |
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| US8923861B2 (en) * | 2012-09-26 | 2014-12-30 | Apple Inc. | Facilitating reselection by a wireless communication device to a first network from a second network after termination of a circuit switched fallback voice call |
| CN104284380A (en) * | 2013-07-09 | 2015-01-14 | 中国移动通信集团公司 | Network return method of multi-mode terminal and multi-mode terminal |
| CN103517316A (en) * | 2013-09-18 | 2014-01-15 | 海信集团有限公司 | Communication method and device based on circuit domain backspacing technology |
| US20160337928A1 (en) * | 2015-05-15 | 2016-11-17 | Qualcomm Incorporated | Measurement reporting for circuit switched fall back services |
| US9629033B2 (en) * | 2015-06-16 | 2017-04-18 | Cisco Technology, Inc. | System and method to facilitate service hand-outs using user equipment groups in a network environment |
| CN106559845A (en) * | 2015-09-24 | 2017-04-05 | 联芯科技有限公司 | The maintaining method of multimode terminal, CSFB implementation methods and GSM neighboring BS information tables |
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