CN105517088A - Switching method and switching system for circuit switched fallback - Google Patents

Abstract

The present invention relates to a voice fallback switching method and system. The voice fallback switching method includes the following steps: a user equipment initiates a voice fallback request to an LTE network side; the user equipment receives a voice fallback request issued by the LTE network side A redirection command; determine whether the redirection command carries the GSM frequency point information of the neighboring cell; if the redirection command does not carry the GSM frequency point information of the neighboring cell, then start the process of switching back to the LTE network. The above voice fallback switching method and system can ensure that the user equipment quickly switches from the 2G or 3G network back to the LTE network when the CSFB fallback fails, thereby improving user experience.

Description

Voice fallback switching method and system

technical field

The invention relates to the technical field of communication, in particular to a voice fallback switching method and system.

Background technique

One of the schemes used for calls under the current LTE (Long Term Evolution, Long Term Evolution) network mode is CSFB (Circuit Switched Fallback, circuit domain fallback), that is, when voice services are performed under the LTE network, the network automatically falls back to 2G (Second Generation, second generation mobile communication technology) or 3G (Third Generation, third-generation mobile communication technology) network, make voice calls through the 2G or 3G network, and switch back to the LTE network after the call service ends. When the terminal initiates a call or receives a paging on the LTE network side, the LTE network sends a GSM frequency point through a redirection command (RRCConnectionRelease) to guide the terminal to fall back to the GSM network. RRC (RadioResourceControl, radio resource control protocol) is normally established, the user equipment (UserEquipment, UE) transmits the CSFB signaling to the UE, LTE releases the RRC link and redirects to GSM (GlobalSystemforMobileCommunication, Global System for Mobile Communications), do it on GSM Access to calls.

However, if the LTE network side does not deliver the GSM frequency point when releasing the RRC connection, CSFB will fail, and the LTE side will initiate a detach process and disconnect from the network. When the mobile phone reselects from 2G or 3G network to 4G network, the mobile phone will stay on 2G or 3G for a long time before reselecting to LTE network. In this case, the user cannot use the LTE network for a long time, and the user experience is poor.

Contents of the invention

Based on this, it is necessary to provide a voice fallback switching method and system for the above technical problems, which can quickly and accurately switch back to the LTE network when the voice fallback fails.

A switching method for voice fallback, comprising the following steps:

The user equipment initiates a voice fallback request to the LTE network side;

The user equipment receives a redirection command issued by the LTE network side for the voice fallback request;

Judging whether the redirection command carries GSM frequency point information of neighboring cells;

If not, start the process of switching back to the LTE network.

In some of these embodiments, the process of switching back to the LTE network includes:

Setting the RSRP threshold of the user equipment from the first RSRP threshold to a second RSRP threshold, wherein the first RSRP threshold is greater than the second RSRP threshold;

judging whether the user equipment reselects to the LTE network;

If yes, reset the RSRP threshold of the user equipment to the first RSRP threshold.

In some of these embodiments, the method also includes:

If the user equipment is not reselected to the LTE network, then measure the signal strength of the LTE network;

judging whether the signal strength of the LTE network is greater than the second RSRP threshold;

If yes, reset the RSRP threshold of the user equipment to the first RSRP threshold.

In some of the embodiments, if the redirection command carries the GSM frequency point information of the neighboring cell, the user equipment is dropped from the LTE network to the 2G or 3G network corresponding to the cell with the highest GSM signal strength.

In some of these embodiments, the method further includes: re-initiating a voice service request after the user equipment is successfully switched back to the LTE network.

A switching system for voice fallback, comprising:

The request module is used for the user equipment to initiate a voice fallback request to the LTE network side;

A receiving module, configured for the user equipment to receive a redirection command issued by the LTE network side for the voice fallback request;

A judging module, configured to judge whether the redirection command carries GSM frequency point information of neighboring cells;

A switching module, configured to start a process of switching back to the LTE network if the redirection command does not carry GSM frequency point information of neighboring cells.

In some of these embodiments, the switching module includes:

A threshold setting module, configured to set the RSRP threshold of the user equipment from a first RSRP threshold to a second RSRP threshold, wherein the first RSRP threshold is greater than the second RSRP threshold;

An LTE network reselection judging module, configured to judge whether the user equipment is reselected to an LTE network;

A threshold resetting module, configured to reset the RSRP threshold of the user equipment to the first RSRP threshold after the user equipment reselects to the LTE network.

In some of these embodiments, the switching module is also used to measure the signal strength of the LTE network when the user equipment is not reselected to the LTE network; determine whether the signal strength of the LTE network is greater than the second RSRP threshold; if If yes, reset the RSRP threshold of the user equipment to the first RSRP threshold.

In some of these embodiments, the handover module is further configured to: when the redirection command carries GSM frequency point information of neighboring cells, fall back the user equipment from the LTE network to the 2G or 3G network corresponding to the cell with the highest GSM signal strength. The internet.

In some of these embodiments, the requesting module is further configured to: re-initiate the voice service request after the user equipment is successfully switched back to the LTE network. In the voice fallback switching method and system described above, after the user equipment initiates a voice fallback request to the LTE network side and receives a redirection command issued by the LTE network side for the voice fallback request, it is determined whether the redirection command carries a neighboring GSM frequency point If the redirection command does not carry the GSM frequency information of the neighboring cell, it means that the CSFB fallback fails, and the process of switching back to the LTE network is started.

The above voice fallback switching method and system can ensure that the user equipment quickly switches from the 2G or 3G network back to the LTE network when the CSFB fallback fails, thereby improving user experience.

Description of drawings

Fig. 1 is the flow chart of the switching method of voice fallback in some embodiments;

Fig. 2 is a schematic diagram of signaling interaction of voice fallback in some embodiments;

FIG. 3 is a schematic flow diagram of switching back to the LTE network in some embodiments;

Fig. 4 is a structural block diagram of a voice fallback switching system in some embodiments.

detailed description

Since the LTE network cannot support voice services in the CS (Circuit Switched, Circuit Switched) domain, when a voice service request occurs, the LTE network will be connected to the 2G or 3G network through the SGs interface, resulting in voice fallback. When CSFB (Circuit Switched Fallback) voice falls back, if the LTE network falls back to 2G or 3G network, such as the mature UMTS terrestrial radio access network (UTRAN, UMTSTerrestrialRadioAccessNetwork) or GSMEDGE access network (GERAN, GSMEDGERadioAccessNetwork). In order to protect the investment in circuit switching (CS, CircuitSwitch), combined with the deployment strategy of the LTE network, the operator can use the existing CS domain voice solution to provide voice services, while the LTE network only processes data services. In this case, the CSFB technology is adopted, that is, when the user equipment under the coverage of the LTE network processes the voice service, the user equipment first falls back to the CS network, and the voice is processed on the CS network, so that the existing CS domain equipment can be reused. The purpose of providing traditional voice services for users in the LTE network.

During the CSFB voice fallback process, if the LTE network side does not deliver the GSM frequency point when releasing the RRC connection, CSFB will fail. ) to search online and register, and stay on the 3G network for a long time before reselecting to LTE. In this case, the user cannot use the LTE network or initiate a voice service for a long time, and the user experience is poor. Therefore, there is a need for a method for quickly switching back to the LTE network when the CSFB voice fallback fails.

In some embodiments, a switching method for voice fallback is proposed, as shown in Figure 1, the method includes the following steps:

Step 102, the user equipment initiates a voice fallback request to the LTE network side.

In some embodiments, the user equipment may be an LTE multimode terminal, and the multimode terminal includes but is not limited to three modes compatible with LTE, TD-SCDMA, and GSM or compatible with three modes: LTE, WCDMA, and GSM. The LTE network side includes a base station, core network equipment, and the like.

Since the LTE network cannot support voice services in the CS domain, when a voice service request occurs, as shown in Figure 2, the user equipment initiates an extended service request to the MME (Mobility Management Entity) of the LTE network, including a CSFB request, and waits for the LTE The fallback process is triggered after the network side responds to the request.

Step 104, the user equipment receives a redirection command issued by the LTE network side for the voice fallback request.

As shown in Figure 2, when the MME receives the CSFB request, if the user is in the connected state, the MME sends a ContextModificationRequest of the user equipment to the eNodeB (base station); if the user is in an idle state, the MME sends an IntialContextSetupRequest to the eNodeB (base station) , both carry the CSFB identifier. Accordingly, the eNodeB issues an R8/R9 redirection command (RRCConnectionRelease) to the user equipment.

Step 106, judging whether the redirection command carries the GSM frequency point information of the neighboring cell, if not, execute step 108, if yes, execute step 110.

In some embodiments, the GSM frequency point information of the neighboring cell is used to guide the user equipment to fall back to the corresponding GSM network. If the redirection command carries the GSM frequency point information of the neighboring cell, the user equipment is directed to fall back to the corresponding GSM network. If the redirection command does not carry the GSM frequency point information of the neighboring cell, the process of switching back to the LTE network is started, so that the user equipment is quickly switched back to the LTE network, and the voice call request is re-initiated.

Step 108, start the process of switching back to the LTE network.

In some embodiments, if the redirection command does not carry the GSM frequency point information of the neighboring cell, the CSFB fallback fails, and the process of switching back to the LTE network is started, so that the user equipment quickly switches back to the LTE network. As shown in Figure 3, the process of switching back to the LTE network includes:

Step 128: Set the RSRP threshold of the user equipment from the first RSRP threshold to a second RSRP threshold, wherein the first RSRP threshold is greater than the second RSRP threshold.

RSRP (ReferenceSignalReceivingPower, reference signal received power) is one of the key parameters that can represent the wireless signal strength in the LTE network and one of the physical layer measurement requirements. It is the signal received on all REs (resource elements) that carry reference signals in a certain symbol. average power.

In some embodiments, the first RSRP threshold is the current RSRP threshold of the user equipment. The second RSRP threshold is an RSRP threshold when the user equipment such as a mobile phone is turned on. For example, the RSRP threshold of the LTE network is set from the original first RSRP threshold (such as -114dBm) to the second RSRP threshold (such as -128dBm, which can be obtained from the system message SIB1) at startup.

Step 148, judge whether the user equipment reselects to the LTE network, if yes, execute step 168, otherwise, execute step 188.

In some embodiments, the signal strength of the LTE network is continuously monitored. When the signal strength (RSRP threshold) of the LTE network is greater than the second RSRP threshold, LTE network reselection will occur. For example, when the first RSRP threshold is reset from -114dBm to the second RSRP threshold -128dBm, it is easy to register on the LTE network.

Through the status value of VOICE_REGISTRATION_STATE, it can be judged whether to reselect to the LTE network. When the state value of VOICE_REGISTRATION_STATE is 1, it is determined that the user equipment has reselected to the LTE network; when the state value of VOICE_REGISTRATION_STATE is 0, it is determined that the user equipment has not reselected to the LTE network.

Step 168, reset the RSRP threshold of the user equipment to the first RSRP threshold.

After the user equipment (mobile phone) reselects to the LTE network, the modem of the user equipment reports the registration status (VOICE_REGISTRATION_STATE). When the modem detects that the user equipment reselects to the LTE network, it resets the RSRP threshold of the LTE network from the second RSRP threshold to the first RSRP threshold. For example, the second RSRP threshold is restored from -128dBm to the first RSRP threshold -114dBm.

Step 188, measure the signal strength of the LTE network.

When the user equipment does not reselect to the LTE network, the signal strength of the LTE network is repeatedly measured until the signal strength of the LTE network (RSRP threshold) is greater than the second RSRP threshold, and the user equipment reselects to the LTE network.

Step 1008, determine whether the signal strength of the LTE network is greater than the second RSRP threshold, if yes, execute step 168, otherwise execute step 188.

When the signal strength (RSRP threshold) of the LTE network is greater than the second RSRP threshold, LTE network reselection will occur. When the modem detects that the user equipment reselects to the LTE network, the RSRP threshold of the user equipment is reset to the first RSRP threshold. If the LTE network is not reselected, the steps of measuring the signal strength of the LTE network and judging whether the user equipment is reselected to the LTE network are repeated until the user equipment is reselected to the LTE network.

From step 128 to step 188 above, by automatically adjusting the RSRP threshold, it is ensured that the user equipment can quickly switch from the 2G or 3G network back to the LTE network when the user equipment is in an LTE weak signal area, thereby improving user experience.

Step 110, fall back the user equipment from the LTE network to the 2G or 3G network corresponding to the cell with the highest GSM signal strength.

If the redirection command carries the GSM frequency point information of the neighboring cell, measure the neighboring cell of the 2G or 3G network, sort the measured values of the neighboring cell, and then perform cross-system reselection according to the sorting situation. The measured value includes received signal strength indication (RSSI, ReceivedSignalStrengthIndicator) or received signal code power (RSCP, ReceivedSignalCodePower) information. Specifically, the RSSI or RSCP can be sorted by using various sorting methods well known to those skilled in the art, and according to the sorting result, the cell with the strongest signal is selected for fallback.

In addition, if the user equipment does not measure the neighboring cells of the 2G or 3G network, the neighboring cells are measured, and cross-system reselection is performed with reference to the measurement results. Specifically, those skilled in the art can use various well-known methods to measure the second-type communication network neighbors, and there are no too many limitations here.

In other embodiments, as shown in FIG. 4 , a voice fallback switching system 400 is proposed, including: a requesting module 402 , a receiving module 404 , a judging module 406 and a switching module 408 .

The request module 402 is used for the user equipment to initiate a voice fallback request to the LTE network side. The receiving module 404 is used for the user equipment to receive a redirection command issued by the LTE network side for the voice fallback request. The judging module 406 is used to judge whether the redirection command carries GSM frequency point information of neighboring cells. The switching module 408 is configured to start a process of switching back to the LTE network if the redirection command does not carry the GSM frequency point information of the neighboring cell.

In some embodiments, the switching module 408 includes: a threshold setting module 428 , an LTE network judging module 448 and a threshold resetting module 468 .

The threshold setting module 428 is configured to set the RSRP threshold of the user equipment from the first RSRP threshold to a second RSRP threshold, wherein the first RSRP threshold is greater than the second RSRP threshold. The LTE network judging module 448 is used for judging whether the user equipment reselects to the LTE network. The threshold reset module 468 is configured to reset the RSRP threshold of the user equipment to the first RSRP threshold when the modem of the user equipment detects that the user equipment reselects to the LTE network.

In some embodiments, the switching module 408 is further configured to repeatedly perform the steps of measuring LTE network signals and determining whether the user equipment reselects to the LTE network when the user equipment has not reselected to the LTE network until the user equipment The device reselects to the LTE network.

In some embodiments, the handover module 408 is further configured to: when the redirection command carries GSM frequency point information of neighboring cells, fall back the user equipment from the LTE network to the 2G or 3G network corresponding to the cell with the highest GSM signal strength.

In some embodiments, the request module 402 is further configured to: re-initiate the voice service request after the user equipment is successfully switched back to the LTE network.

In the voice fallback switching method and system of the above embodiments, after the user equipment initiates a voice fallback request to the LTE network side and receives a redirection command issued by the LTE network side for the voice fallback request, it is judged whether the redirection command carries a neighboring cell GSM Frequency point information, if the redirection command does not carry the GSM frequency point information of the neighboring cell, it means that the CSFB fallback fails, and the process of switching back to the LTE network is started. If the redirection command carries the GSM frequency point information of the neighboring cell, the user equipment will fall back from the LTE network to the 2G or 3G network corresponding to the cell with the highest GSM signal strength to realize the voice call. The above voice fallback switching method and system can ensure that the user equipment quickly switches back to the LTE network from the 2G or 3G network when the CSFB fallback fails, thereby improving user experience.

The various technical features of the above-mentioned embodiments can be combined arbitrarily. For the sake of concise description, all possible combinations of the various technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, should be considered as within the scope of this specification.

The above-mentioned embodiments only express several implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but should not be construed as limiting the patent scope of the invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (10)

1. a changing method for voice fallback, is characterized in that, comprises the following steps:

Subscriber equipment initiates voice fallback request to LTE network side;

Described subscriber equipment receives the redirect command that LTE network side issues for described voice fallback request;

Judge whether described redirect command carries adjacent area GSM frequency point information;

If not, then the flow process switching back LTE network is started.

2. changing method according to claim 1, is characterized in that, the flow process that LTE network is returned in described switching comprises:

The RSRP threshold value of described subscriber equipment is set to the 2nd RSRP threshold value by a RSRP threshold value, and wherein, a described RSRP threshold value is greater than described 2nd RSRP threshold value;

Whether gravity treatment is to LTE network to judge described subscriber equipment;

If so, then the RSRP threshold value of described subscriber equipment is reset to a described RSRP threshold value.

3. changing method according to claim 2, is characterized in that, described method also comprises:

If the non-gravity treatment of described subscriber equipment is to LTE network, then measure LTE network signal strength signal intensity;

Judge whether described LTE network signal strength signal intensity is greater than described 2nd RSRP threshold value;

If so, then the RSRP threshold value of described subscriber equipment is reset to a described RSRP threshold value.

4. changing method according to claim 1, is characterized in that, if described redirect command carries adjacent area GSM frequency point information, then subscriber equipment is fallen back to 2G corresponding to the maximum community of GSM signal strength signal intensity or 3G network from LTE network.

5. changing method according to claim 1, is characterized in that, described method also comprises: after described subscriber equipment successful switch returns LTE network, again initiate voice service request.

6. a switched system for voice fallback, is characterized in that, comprising:

Request module, initiates voice fallback request for subscriber equipment to LTE network side;

Receiver module, for the redirect command that described subscriber equipment reception LTE network side issues for described voice fallback request;

Judge module, for judging whether described redirect command carries adjacent area GSM frequency point information;

Handover module, if do not carry adjacent area GSM frequency point information for described redirect command, then starts the flow process switching back LTE network.

7. system according to claim 6, is characterized in that, described handover module comprises:

Threshold setting module, for the RSRP threshold value of described subscriber equipment is set to the 2nd RSRP threshold value by a RSRP threshold value, wherein, a described RSRP threshold value is greater than described 2nd RSRP threshold value;

LTE network gravity treatment judge module, for judging described subscriber equipment, whether gravity treatment is to LTE network;

Threshold value resets module, for when after described subscriber equipment gravity treatment to LTE network, then the RSRP threshold value of described subscriber equipment is reset to a described RSRP threshold value.

8. system according to claim 6, is characterized in that, described handover module is also for when the non-gravity treatment of described subscriber equipment is to LTE network, and LTE network signal strength signal intensity then measured by described subscriber equipment; Judge whether described LTE network signal strength signal intensity is greater than described 2nd RSRP threshold value; If so, then the RSRP threshold value of described subscriber equipment is reset to a described RSRP threshold value.

9. system according to claim 6, it is characterized in that, described handover module also for: when described redirect command carries adjacent area GSM frequency point information, subscriber equipment is fallen back to 2G corresponding to the maximum community of GSM signal strength signal intensity or 3G network from LTE network.

10. system according to claim 6, is characterized in that, described request module also for: after described subscriber equipment successful switch returns LTE network, again initiate voice service request.