CN106341803A - Method for improving call completion ratio of LTE terminal equipment and terminal equipment - Google Patents

Abstract

The present invention provides a method and terminal equipment for improving the call-through rate of LTE terminal equipment. The method includes: UE residing in the LTE network sends an ESR (Extended Service Request, Extended Service Request) request to initiate a voice call; receiving network side The downlink signal sent by the device, the downlink signal carries the configured 2G/3G network target frequency point and the information of the adjacent cell frequency point; if the terminal device receives the indication information of network congestion and cannot fall back to the target frequency point, it will search for the neighbor The frequency point where the signal quality of the cell meets the preset condition; the terminal device camps on the frequency point where the signal quality of the adjacent cell meets the preset condition; and the terminal device initiates a voice service request again on the 2G/3G network where it resides . Through the above method, the terminal equipment can quickly access the neighboring GSM network when receiving the network congestion information, which improves the call throughput rate of the LTE terminal equipment and ensures a good communication effect.

Description

Method for Improving Call Through Rate of LTE Terminal Equipment and Terminal Equipment

technical field

The present invention relates to the field of communication technology, in particular to a method and terminal equipment for improving the call-through rate of LTE terminal equipment.

Background technique

Since LTE is a network standard that only supports the data domain, when a mobile phone needs to use the voice call function, there are usually two solutions. One is to use Volte (Voice over LTE) based on Voice over IP (VoIP for short). ) technology, and the other is to use the Circuit Switched Domain Fall Back (CSFB) technology to allow the mobile phone to fall back to the 2G/3G network that supports the circuit domain.

The former VoIP-based Volte technology is still in the initial stage of network deployment, and has not been commercialized in many areas. At present, when most people make calls with LTE mobile phones, they still use the second solution, which uses CSFB technology to fall back to the 2G/3G network for calls.

Circuit domain fallback can enable terminal devices to initiate voice and other circuit switched (Circuit Switched (CS) services for short) under LTE access, receive paging for voice and other CS services, and can perform long-term evolution (LongTerm Evolution, LTE) The ongoing packet switching (Packet Switch, PS) service under system access is correctly processed. In CSFB technology, in the dual coverage area of LTE and 2G/3G, for voice services, the terminal device can trigger the fallback from LTE access to 2G/3G network access and perform CS services.

In the prior art, when the user equipment is located in the overlapping coverage area of 2G, 3G and LTE networks, and the terminal initiates a voice call or voice paging to a mobility management entity (Mobility Management Entity, LTE network for short) under the LTE network , the LTE base station sends an Extended Service Request (Extended Service Request) to the LTE network, so that the LTE network knows that the terminal device will perform circuit domain services, and the LTE network then instructs the terminal to fall back to the 2G network or 3G network. When the terminal falls back to the 2G network or After the 3G network, an access request is initiated to the Mobile Switch Center (MSC), and the MSC decides whether to allow the terminal to initiate circuit domain services according to the priority of the terminal user and its own system load status; when the terminal is allowed to access , the terminal performs network switching. If the circuit domain system is overloaded at this time and the permission is rejected, the network switchover will fail, resulting in the final call failure, and it may also cause the redial call to fail, resulting in poor user experience.

Contents of the invention

In view of this, the present invention provides a method for increasing the call completion rate of LTE terminal equipment and the terminal equipment, which can effectively improve the call completion rate of the terminal equipment and improve user experience.

The first aspect of the present invention provides a method for improving the call-through rate of LTE terminal equipment, the method comprising:

The UE residing in the LTE network sends an ESR (Extended Service Request, extended service request) request to initiate a voice call;

Receive the downlink signal sent by the network side equipment, the downlink signal carries the information of the configured 2G/3G network target frequency point and adjacent cell frequency points;

If the terminal device receives the indication information of network congestion and cannot fall back to the target frequency point, search for a frequency point whose signal quality of the neighboring cell meets the preset condition;

The terminal resides at a frequency point where the signal quality of the neighboring cell satisfies a preset condition;

The terminal device initiates a voice service request again on the 2G/3G network where it resides.

Using the method provided in the first aspect of the present invention, when the terminal device receives the indication information of network congestion and cannot fall back to the target frequency point, it can search for the frequency point whose signal quality of the neighboring cell meets the preset condition, and access The frequency point where the signal quality of the neighboring cell meets the preset condition.

Further, the indication information of the network congestion is #39, and the #39 indicates that the circuit domain core network is congested. When the terminal device receives #39, it can start to search the frequency points of the neighboring cells, so as to quickly access the neighboring cells that meet the conditions.

Further, the preset condition is that the RSRP (Reference Signal Received Power, reference signal reception strategy) value is greater than a preset threshold or the RSRP is the largest among all neighboring cell frequency points.

Further, if the target frequency point is a frequency point of the 2G network, when the terminal device receives the indication information of network congestion and cannot fall back to the target frequency point, the terminal device searches for signals of neighboring cells of the 3G network The frequency point whose quality meets the preset condition.

Further, if the target frequency point is the frequency point of the 3G network, when the terminal device receives the indication information of network congestion and cannot fall back to the target frequency point, the terminal device searches for signals of neighboring cells of the 2G network The frequency point whose quality meets the preset condition.

In the second aspect of the present invention, a terminal device is provided, including a search module, a sending module, and a receiving module. The search module is used to search the LTE network and reside in the LTE network when the terminal device is turned on; the sending module uses When sending an ESR (Extended Service Request, extended service request) request to initiate a voice call; the receiving module is used to receive the downlink signal sent by the network side device, the downlink signal carries the configured 2G/3G network target frequency point and adjacent cell frequency point information; if the terminal device receives an indication of network congestion and cannot fall back to the target frequency point, the search module is also used to search for a frequency point where the signal quality of the neighboring cell meets the preset condition, so that the terminal device can camp on At a frequency point where the signal quality of the neighboring cell satisfies a preset condition; the sending module is further configured to initiate a voice service request again after the terminal device resides on a 2G/3G network.

Further, the indication information of the network congestion is #39, and the #39 indicates that the circuit domain core network is congested.

Further, the preset condition is that the RSRP (Reference Signal Received Power, reference signal reception strategy) value is greater than a preset threshold or the RSRP is the largest among all neighboring cell frequency points.

Further, if the target frequency point is a frequency point of a 2G network, when the terminal device receives an indication of network congestion and cannot fall back to the target frequency point, the search module is used to search for a 3G network neighbor Frequency points whose signal quality meets the preset conditions.

Further, if the target frequency point is a frequency point of a 3G network, when the terminal device receives an indication of network congestion and cannot fall back to the target frequency point, the search module is used to search for a 2G network neighbor The frequency points where the signal quality of the zone meets the preset conditions.

The beneficial effects of the technical solution of the present invention at least include:

The technical solution of the present invention does not continue to reside in the LTE network when the circuit domain core network is congested and the CSFB process network handover fails, but by searching the circuit domain network of the adjacent cell, the terminal directly tries to find a suitable cell in the network to reside in , and initiate access in the park mode to perform voice services. The technical solution of the present invention can reduce the time overhead of returning to the LTE network again and establishing an ESR request, and can directly select a neighboring cell network to reside in during the dwell period of network handover failure, greatly shortening the delay required for re-initiating circuit domain services. Improving the response speed of the system can also increase the success rate of call establishment, and can also shorten the time required to establish a call again, thereby improving communication quality and user experience.

Description of drawings

Fig. 1 is a kind of CSFB calling signaling flowchart;

Fig. 2 is a flowchart of a method for improving the call-through rate of LTE terminal equipment according to an embodiment of the present invention;

Fig. 3 is a flowchart of a method for improving the call-through rate of LTE terminal equipment according to another embodiment of the present invention;

FIG. 4 is a block diagram of a terminal device according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a hardware structure of a terminal device according to an embodiment of the present invention.

Description of main component symbols:

100-terminal equipment, 10-searching module, 20-sending module, 30-receiving module, 200-terminal equipment, 201-memory, 202-processor.

detailed description

In order to make the purpose, features and effects of the present invention more obvious and understandable, the specific implementation manners of the present invention will be described in detail below in conjunction with the accompanying drawings.

The terminal equipment involved in this application, that is, user equipment (User Equipment, UE), can be a wireless terminal or a wired terminal, and a wireless terminal can be a device that provides voice and/or data connectivity to users, and a wireless terminal A handheld device, or other processing device connected to a wireless modem. The wireless terminal can communicate with one or more core networks via the radio access network (Radio Access Network, RAN), and the wireless terminal can be a mobile terminal, such as a mobile phone (or called a "cellular" phone) and a computer with a mobile terminal , for example, may be portable, pocket, handheld, computer built-in, or vehicle-mounted mobile devices that exchange voice and/or data with the radio access network. For example, personal communication service (Personal Communication Service, PCS) phone, cordless phone, session initiation protocol (SIP) phone, wireless local loop (Wireless Local Loop, WLL) station, personal digital assistant (Personal Digital Assistant, PDA) and other equipment. The wireless terminal can also be called a system, a subscriber unit (SubscriberUnit), a subscriber station (Subscriber Station), a mobile station (Mobile Station), a mobile station (Mobile), a remote station (Remote Station), an access point (Access Point), a remote Terminal (Remote Terminal), Access Terminal (Access Terminal), User Terminal (User Terminal), User Agent (User Agent), User Equipment (User Device), or User Equipment (User Equipment).

CSFB fallback in the circuit domain is to enable the terminal to initiate CS services such as voice services and receive paging of CS services such as voice services under LTE access, and to correctly process the ongoing PS services of the terminal in the LTE network , resulting in CSFB technology. In fact, it is to switch the voice call to the 2G or 3G network.

In the early stage of TD-LTE network construction, if the operator already has a mature UMTS Terrestrial Radio Access Network (UTRAN)/GSM Radio Access Network (GSMED GE Radio Access Network, GERAN) network, for CS investment Combined with the deployment strategy of the TD-LTE network, operators can use the original CS domain voice solution to provide voice services, while the TD-LTE network only handles data services (including IMS data services). In this case, CSFB technology is adopted, that is, when the UE under LTE coverage processes voice services, the terminal first falls back to the CS (circuit domain) network, and processes voice services on the CS network; in this way, the existing CS domain can be reused. The device is used to provide traditional voice services for users in the TD-LTE network.

However, the use of CSFB has a prerequisite, that is, only in the overlapping coverage area of the Evolved UMTS Terrestrial Radio Access Network (Evolved UMTS Terrestrial Radio Access Network, E-UTRAN) and UTRAN/GERAN, and the user equipment has the CSFB function Only then can CS domain fallback be used.

The present invention relates to an LTE network, a 3G network and a 2G network, and specifically falls back from the LTE network to the 2G network from the 3G network. The wireless network architecture is described below by taking an LTE network as an example.

A wireless network architecture may include several eNBs and other network entities. An eNB may be a base station that communicates with a user equipment device (UE) and may be referred to as a base station, Node B, access point, and so on. Each eNB can provide communication coverage for a specific geographic area. In 3GPP, the term "cell" can refer to a coverage area of an eNB and/or of an eNB subsystem serving this coverage area, depending on the context in which the term is used.

An eNB may provide communication coverage for macro cells, pico cells, femto cells, and/or other types of cells. A macro cell may cover a relatively large geographic area (eg, several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with a service subscription. A femtocell may cover a relatively small geographic area (e.g., a home) and may allow UEs associated with the femtocell (e.g., UEs in a Closed Subscriber Group (CSG), UEs for users in a home, etc. ) for restricted access. An eNB for a macro cell may be referred to as a macro eNB (ie, a macro base station). An eNB for a pico cell may be referred to as a pico eNB (ie, pico base station). An eNB for a femto cell may be referred to as a femto eNB (ie, femto base station) or a home eNB. An eNB may support one or more (eg, three) cells.

Wireless networks may also include relay stations. A relay station is a station that receives transmissions of data and/or other information from an upstream station (eg, an eNB or a UE) and sends transmissions of data and/or other information to an upstream station (eg, a UE or an eNB). A relay station may also be a UE that relays transmissions for other UEs. A relay station may also be called a relay eNB, a relay, and the like.

The wireless network may be a heterogeneous network (HerNet) comprising different types of eNBs such as macro eNBs, pico eNBs, femto eNBs, relays, and so on. These different types of eNBs may have different transmit power levels, different coverage areas, and different impacts on interference in the wireless network. For example, macro eNBs have high transmit power levels (eg, 20W) while pico eNBs, femto eNBs, and relays have lower transmit power levels (eg, 1W).

Also included in the wireless network is a network controller that can couple to a collection of eNBs and provide coordination and control for these eNBs. The network controller may communicate with the eNBs via the backhaul. The eNBs may also communicate with each other, eg, directly or indirectly via a wireless or wired backhaul.

Please refer to Figure 1. When the terminal (UE) actively initiates a voice service request, if the CSFB process can normally fall back from the LTE network to the 2G/3G network, the following CSFB calling process (reconstruction signaling process) can be performed:

1. The UE initiates a CSFB (Circuit Domain Fallback) voice service request.

2. The MME (Mobile Management Entity, mobile management entity) sends an S1-AP UE CONTEXTMODIFICATION REQUEST message to the eNodeB, including CSFB indication information (CS Fallback Indicator). This message indicates to the eNodeB that the UE needs to fall back to the UTRAN (3G) network or the GERAN (2G) network due to the CSFB service.

3. The eNodeB requires the UE to start measuring cells of different systems, obtains the measurement report reported by the UE, and determines the redirected target system cell. Then send the specific wireless configuration information of the target system to the UE, and release the connection.

4. The UE accesses the target system cell and initiates a CM SERVICE REQUEST in the CS domain.

5. If the MSC to which the target system cell belongs is different from the MSC (Mobile Switching Center, Mobile Switching Center) registered when the UE attaches to the EPS (Evolved Packet System, Evolved Packet System) network, then when the MSC receives the service request from the UE, Since there is no information about the UE, an implicit location update process can be adopted to accept the user request. If the MSC does not support implicit location update, and the MSC has no user data (that is, the serving MSC is different from the MSC registered with the EPS/IMSI), the user's service request is rejected. If the MSC rejects the user's service request, the UE will initiate a CS domain location update procedure.

6. CS domain voice call establishment process.

Please refer to Fig. 2, the embodiment of the present invention provides a kind of method that improves the call through rate of LTE terminal equipment, wherein, LTE terminal equipment takes mobile phone as example, comprises the following steps:

S101: The function of the LTE terminal device is normal. After starting up, the device can reside in a 2G (GSM, CDMA), 3G (WCDMA, CDMA2000, TD-SCDMA) or 4G (TD-LTE, FDD-LTE) network, and can perform 2G/3G Voice service and 4G data service. 2G and 3G networks also support data services, but the data transmission speed is relatively slow, which does not meet the current demand for large data volume services.

S102: When the terminal device searches for a stable 4G signal, access and camp on the LTE network. The LTE network only supports data services, that is, packet switching services. When voice services need to be supported, Volte technology can be used without switching networks, but this technology has not been commercially used on a large scale in my country. The current voice service is mainly realized through the CSFB technology, which makes the terminal equipment fall back from the LTE network to the 2G/3G network supporting the circuit domain.

S103: The terminal device residing in the LTE network initiates a voice call service; the CSFB technology can be used to trigger the terminal device to fall back from the LTE network to the 2G/3G network access to perform voice services in the dual coverage area of LTE and 2G/3G .

S104: When the terminal device initiates a voice call under the LTE network, the LTE base station sends an ESR (Extended Service Request, Extended Service Request) to the LTE network, so that the LTE network knows that the terminal device will perform circuit domain services, and the LTE network then instructs the terminal to fall back to the LTE network. 2G or 3G network, when the terminal falls back to the 2G or 3G network, it initiates an access request to the MSC, and the MSC decides whether to allow the terminal to initiate circuit domain services according to the priority of the terminal user and its own system load status; When input, the terminal performs network switching. If the load of the circuit domain system is too heavy at this time, it will result in the failure of the terminal switching, resulting in the failure of the final call, and may also cause the failure of initiating a redial call. When receiving error #39 of network congestion, the terminal executes the following step S05 to avoid voice service interruption.

S105: Read the cell and frequency point of the adjacent cell supporting the CS domain service network, and initiate a network search to select a target cell that the terminal device can access, and the target cell is adjacent to the LTE network in the 2G/3G network district.

S106: After the terminal equipment resides in the target cell determined by the network, voice services can be performed under the network. At this time, the mobile phone initiates a voice service call again.

S107: The terminal device can perform a voice call service on the 2G/3G network of the neighboring cell, which can solve the problem of low call success rate caused by network congestion.

S108: After the call ends, the terminal device performs a network switch again to return to the LTE network.

Referring to Fig. 3, the embodiment of the present invention also provides a method for improving the call-through rate of LTE terminal equipment, the method includes the following steps:

S201: A UE residing in an LTE network sends an ESR (Extended Service Request, extended service request) request to initiate a voice call.

S202: Receive a downlink signal sent by the network side device, the downlink signal is an RRCConnection Release signal, and carries information about the configured 2G/3G network target frequency point and adjacent cell frequency points.

S203: If the terminal device receives the indication information of network congestion and cannot fall back to the target frequency point, search for a frequency point whose signal quality of the neighboring cell meets the preset condition. In the embodiment of the present invention, the indication information of the network congestion is #39, and #39 indicates that the circuit domain core network is congested. The preset condition is that the RSRP (Reference Signal Received Power, reference signal reception strategy) value is greater than a preset threshold or the RSRP is the largest among all adjacent cell frequencies.

S204: The terminal device camps on a frequency point where the signal quality of the neighboring cell satisfies a preset condition.

S205: The terminal device initiates a voice service request again on the 2G/3G network where it resides.

Optionally, if the target frequency point is a frequency point of the 2G network, when the terminal device receives the indication information of network congestion and cannot fall back to the target frequency point, the terminal device searches for the signal quality of the neighboring cell of the 3G network Frequency points that meet the preset conditions.

Optionally, if the target frequency point is a frequency point of the 3G network, when the terminal device receives the indication information of network congestion and cannot fall back to the target frequency point, the terminal device searches for the signal quality of the neighboring cell of the 2G network Frequency points that meet the preset conditions.

Please refer to FIG. 4 , an embodiment of the present invention provides a terminal device 100, including a search module 10, a sending module 20, and a receiving module 30. The search module 10 is used to search for an LTE network when the terminal device is powered on and reside in LTE network; the sending module 20 is used to send an ESR (Extended Service Request, extended service request) request to initiate a voice call; the receiving module 30 is used to receive the downlink signal sent by the network side, and the downlink signal carries the configured 2G/3G Information about network target frequency points and adjacent cell frequency points. If the terminal device 100 receives the indication information of network congestion and cannot fall back to the target frequency point, the search module 10 is also used to search for a frequency point whose signal quality in the neighboring cell meets the preset condition, so that the terminal device 100 can park Stay at the frequency point where the signal quality of the neighboring cell satisfies the preset condition; the sending module 20 is also used to initiate a voice service request again after the terminal device resides in the 2G/3G network.

The indication information of the network congestion is #39, and #39 indicates that the circuit domain core network is congested; the search module 10 of the terminal device 100 receives #39 and starts to search the frequency point whose signal quality of the neighboring cell meets the preset condition, so that The terminal device 100 can quickly search for an accessible neighboring cell when the network is congested, so as to avoid interruption of the voice call.

Specifically, the signal quality meeting the preset condition means that the RSRP (Reference Signal Received Power, reference signal receiving strategy) value is greater than the preset threshold value, and the RSRP value is greater than the threshold value for neighboring cells and frequency points (a cell may have a or multiple frequency points) may be more than one, and a frequency point that satisfies the conditions can be randomly selected for access, which can reduce the time for searching the network, and the terminal device can quickly access the neighboring cell that meets the conditions; the signal quality Satisfying the preset condition may also mean that the RSRP is the largest among all adjacent cell frequencies, and selecting the frequency point with the largest RSRP for access can enable the terminal device to access the cell and frequency point with the best signal and ensure communication quality.

The downlink signal received by the receiving module 30 is an RRC Connection Release signal, which carries information about the configured GSM (2G)/UTRAN (3G) network target frequency point and adjacent cell frequency points.

Optionally, if the target frequency point is a frequency point of a 2G network, when the terminal device 100 receives an indication of network congestion and cannot fall back to the target frequency point, the search module 10 is configured to search for a 3G network The frequency point where the signal quality of the neighboring cell meets the preset condition.

Optionally, if the target frequency point is a frequency point of a 3G network, when the terminal device 100 receives an indication message of network congestion and cannot fall back to the target frequency point, the search module 10 searches for neighboring cells of the 2G network The frequency points whose signal quality meets the preset conditions.

FIG. 5 is another schematic structural diagram of a terminal device 200 according to an embodiment of the present invention. The terminal device 200 includes at least: a memory 201 and a processor 202, wherein:

The memory 201 may include a read-only memory and a random access memory, and provide instructions and data to the processor 202. A part of the memory 201 may also include a high-speed random access memory (RAM, Random Access Memory), and may also include a Stable memory (non-volatile memory).

The memory 201 stores the following elements, executable modules or data structures, or their subsets, or their extended sets.

Operation instructions: include various operation instructions for realizing various operations.

Operating system: includes various system programs for implementing various basic services and processing hardware-based tasks.

In the embodiment of the present invention, the processor 202 performs the following operations by calling the operation instruction stored in the memory 201 (the operation instruction can be stored in the operating system):

If the terminal device receives the indication information #39 of network congestion and cannot fall back to the circuit domain (CS), it searches for a frequency point whose signal quality of the neighboring cell meets the preset condition, so that the terminal device accesses the signal quality of the neighboring cell to meet the The frequency point of the preset condition.

In addition, the processor 202 is further configured to execute all or part of the steps in the method embodiment shown in FIG. 2 or FIG. 3 , which will not be detailed here.

The terminal device in the embodiment of the present invention is the aforementioned user equipment in practical application, which may be a wireless terminal or a wired terminal. The terminal device has the functional modules shown in FIG. 4 or the structure shown in FIG. 5 . Wherein, the wireless terminal can communicate with one or more core networks via a radio access network (for example, RAN, RadioAccess Network), and the wireless terminal can be a mobile terminal, such as a mobile phone (or called a "cellular" phone) and a mobile phone The computers of the terminals, which may be, for example, portable, pocket, hand-held, built-in or vehicle-mounted mobile devices, exchange speech and/or data with the radio access network. Specifically, details are not described here.

Those skilled in the art can clearly understand that for the convenience and brevity of the description, the specific working process of the above-described system, device and unit can refer to the corresponding process in the foregoing method embodiment, which will not be repeated here.

In the several embodiments provided in this application, it should be understood that the disclosed system, device and method can be implemented in other ways. For example, the device embodiments described above are only illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or May be integrated into another system, or some features may be ignored, or not implemented. In another point, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces, and the indirect coupling or communication connection of devices or units may be in electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place, or may be distributed to multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, each unit may exist separately physically, or two or more units may be integrated into one unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

If the integrated unit is realized in the form of a software function unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, the essence of the technical solution of the present invention or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium , including several instructions to make a computer device (which may be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-OnlyMemory), random access memory (RAM, Random Access Memory), magnetic disk or optical disk and other media that can store program codes.

As mentioned above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still understand the foregoing The technical solutions recorded in each embodiment are modified, or some of the technical features are replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims (10)

1. a kind of method of raising lte terminal unit call completion ratio is it is characterised in that the method includes:

Reside at the ue in lte network and send esr (extended service request, expansion service is asked) request initiation Audio call；

Receive the downstream signal that network equipment sends, this downstream signal carries 2g/3g network objectives frequency and the adjacent area of configuration The information of frequency；

If terminal unit receives the configured information of network congestion and can not fall back to described target frequency, searching neighboring area signal matter Amount meets pre-conditioned frequency；

Described terminal unit resides in described neighboring cell signal quality and meets pre-conditioned frequency；

Described terminal unit initiates voice service request again in resident 2g/3g network.

2. the method for raising lte terminal unit call completion ratio according to claim 1 is it is characterised in that described network congestion Configured information be #39, described #39 indicating circuit domain core net congestion.

3. the method for raising lte terminal unit call completion ratio according to claim 1 and 2 is it is characterised in that described default bar Part is that rsrp (reference signal received power, reference signal receives attack strategy) value is more than default threshold value Or rsrp is maximum in the frequency of all adjacent areas.

If 4. the method for raising lte terminal unit call completion ratio according to claim 1 is it is characterised in that described target Frequency is the frequency of 2g network, then receive the configured information of network congestion in described terminal unit and can not fall back to described target During frequency, described terminal unit search 3g network neighbor signal quality meets pre-conditioned frequency.

If 5. the method for raising lte terminal unit call completion ratio according to claim 1 is it is characterised in that described target Frequency is the frequency of 3g network, then receive the configured information of network congestion in described terminal unit and can not fall back to described target During frequency, described terminal searching 2g network neighbor signal quality meets pre-conditioned frequency.

6. a kind of terminal unit, including search module, sending module and receiver module, described search module sets for described terminal Search for lte network during standby start and reside at lte network；Described sending module is used for sending esr (extended service Request, expansion service is asked) request initiation audio call；Described receiver module is used for receiving under network equipment transmission Row signal, this downstream signal carries the 2g/3g network objectives frequency of configuration and the information of adjacent area frequency；It is characterized in that,

If terminal unit receives the configured information of network congestion and can not fall back to described target frequency, described search module is also used Meet pre-conditioned frequency in searching neighboring area signal quality, so that described terminal unit resides in described neighboring cell signal quality completely The pre-conditioned frequency of foot；Described sending module is additionally operable to initiate language again after described terminal unit resides at 2g/3g network Sound business is asked.

7. terminal unit according to claim 6 is it is characterised in that the configured information of described network congestion is #39, institute State #39 indicating circuit domain core net congestion.

8. the terminal unit according to claim 6 or 7 it is characterised in that described pre-conditioned be rsrp (reference Signal received power, reference signal receives attack strategy) value is more than default threshold value or rsrp in all adjacent areas frequency Middle maximum.

If 9. terminal unit according to claim 6 is it is characterised in that described target frequency is the frequency of 2g network, Then when described terminal unit receives the configured information of network congestion and can not fall back to described target frequency, described search module Meet pre-conditioned frequency for searching for 3g network neighbor signal quality.

If 10. terminal unit according to claim 6 is it is characterised in that described target frequency is the frequency of 3g network, Then when described terminal unit receives the configured information of network congestion and can not fall back to described target frequency, described search module Meet pre-conditioned frequency for searching for 2g network neighbor signal quality.