CN112995972A

CN112995972A - Call establishment method and terminal equipment

Info

Publication number: CN112995972A
Application number: CN202110264690.1A
Authority: CN
Inventors: 袁锴; 段小嫣; 张博; 睢菲菲; 丁明
Original assignee: Honor Device Co Ltd
Current assignee: Honor Device Co Ltd
Priority date: 2017-02-27
Filing date: 2017-02-27
Publication date: 2021-06-18
Anticipated expiration: 2037-02-27
Also published as: CN108696853A; WO2018153274A1; CN108696853B; CN112995972B

Abstract

The embodiment of the invention provides a method for establishing a call applied to terminal equipment, which comprises the following steps: sending a first request message to a network device in a first communication network, wherein the terminal device currently resides in a cell in the first communication network, the first request message including emergency call indication information; receiving a first response message sent by the network equipment, wherein the first response message comprises a carrier frequency parameter in the second communication network; measuring a first cell, wherein the first cell comprises at least one cell in a second communication network, and the carrier frequency parameter of each cell in the first cell meet a preset relationship; judging whether a second cell supports the emergency call service or not, wherein the second cell is one of the first cells; when the second cell supports the emergency call service, the second cell is resided; and sending a second request message to the network equipment in the second communication network, wherein the second request message is used for requesting to establish the emergency call.

Description

Call establishment method and terminal equipment

Technical Field

The embodiment of the invention relates to the technical field of communication, in particular to a call establishment method and terminal equipment.

Background

The Long Term Evolution (LTE) system belongs to the fourth Generation mobile communication system (4 th Generation, 4G), and the LTE network generally supports faster data rate than the 2G and 3G networks. However, in some cases, the LTE network may not fully support some of the traffic that can be handled by the legacy network, so there is typically an overlapping area for the deployment of the LTE network and the legacy network, and the terminal device can switch between the LTE network and the legacy network when traffic needs. For example, in some cases, the LTE network does not support voice calls, and thus, when a terminal device receives or originates a voice call while connected to a network that supports data sessions but does not support voice calls, the terminal device may perform a Circuit Switched Fallback (CSFB) procedure to fall back to a legacy network that supports voice calls.

When the terminal device performs the CSFB procedure to fall back to a conventional network, such as a Global System for Mobile Communications (GSM) network, and initiates an emergency call (e.g., dialing an emergency call number such as 110 or 911), the emergency call may fail.

Disclosure of Invention

The embodiment of the invention provides a call establishment method, which aims to improve the success rate of establishing an emergency call after CSFB (Circuit switched fallback) of terminal equipment.

In a first aspect, an embodiment of the present invention provides a method for call setup, where the method is applied to a terminal device, and includes:

sending a first request message to a network device in a first communication network, wherein the terminal device currently resides in a cell in the first communication network, the first request message including emergency call indication information; receiving a first response message sent by the network equipment, wherein the first response message comprises a carrier frequency parameter in the second communication network; measuring a first cell, wherein the first cell comprises at least one cell in a second communication network, and the carrier frequency parameter of each cell in the first cell meet a preset relationship; judging whether a second cell supports the emergency call service or not, wherein the second cell is one of the first cells; when the second cell supports the emergency call service, the second cell is resided; and sending a second request message to the network equipment in the second communication network, wherein the second request message is used for requesting to establish the emergency call.

With reference to the first aspect, in one implementation manner, the method further includes: and when the second cell does not support the emergency call service, judging whether a third cell supports the emergency call service, wherein the third cell is a cell except the second cell in the first cell.

With reference to the first aspect and all implementations thereof, in another implementation, the carrier frequency parameter includes one carrier frequency, a plurality of carrier frequencies, or a carrier frequency range. When the carrier frequency parameter comprises a carrier frequency, the preset relationship comprises that the cell frequency is the same as the carrier frequency; when the carrier frequency parameter comprises a plurality of carrier frequencies, the preset relationship comprises that the cell frequency is one of the plurality of carrier frequencies; when the carrier frequency parameter comprises a carrier frequency range, the predetermined relationship comprises the cell frequency being within a carrier frequency range.

With reference to the first aspect and all implementation manners thereof, in another implementation manner, the determining whether the second cell supports the emergency call service includes: when the EC value of the emergency call allowed in the system information broadcasted by the second cell is 0 or when the EC value of the emergency call allowed in the system information broadcasted by the second cell is 1 and the access category of the terminal equipment belongs to the category 11-15, judging that the second cell supports the emergency call service; and when the EC value of the allowable emergency call in the system information broadcasted by the second cell is 1 and the access category of the terminal equipment does not belong to the categories 11-15, judging that the second cell does not support the emergency call service.

With reference to the first aspect and all implementation manners of the first aspect, in another implementation manner, before camping on the second cell, the method further includes: and judging whether the ID of the Public Land Mobile Network (PLMN) to which the second cell belongs is the same as the ID of the first PLMN or the ID of the second PLMN, and triggering the step of residing in the second cell when the ID of the PLMN to which the second cell belongs is the same as the ID of the first PLMN or the ID of the second PLMN, wherein the ID of the first PLMN is the ID of the PLMN currently registered by the terminal equipment, and the ID of the second PLMN is the ID of the PLMN equivalent to the PLMN currently registered by the terminal equipment.

With reference to the first aspect and all implementations thereof, in another implementation, the method further includes: and when the ID of the PLMN to which the second cell belongs is different from the ID of the first PLMN or the ID of the second PLMN, judging whether the second cell is the cell with the strongest received signal power in the cells meeting the preset conditions in the first cell, and when the second cell is the cell with the strongest received signal power in the cells meeting the preset conditions in the first cell, triggering the step of residing in the second cell.

With reference to the first aspect and all implementation manners of the first aspect, in another implementation manner, the first communication network is a long term evolution LTE network, and the second communication network is a global system for mobile communications GSM network.

In a second aspect, an embodiment of the present invention provides a method for call setup, where the method is applied to a terminal device, and includes: sending a first request message to a network device in a first communication network, wherein the terminal device currently resides in a cell in the first communication network, the first request message including emergency call indication information; receiving a first response message sent by the network equipment, wherein the first response message comprises a carrier frequency parameter in the second communication system; measuring a first cell, wherein the first cell comprises at least one cell in a second communication network, and the carrier frequency parameter of each cell in the first cell meet a preset relationship; camping on a second cell, wherein the second cell is one of the first cells; judging whether the second cell supports the emergency call service; when the second cell does not support the emergency call service, judging whether a third cell supports the emergency call service, wherein the third cell is a cell except the second cell in the first cell; when the third cell supports the emergency call service, reselecting the third cell; and sending a second request message to the network equipment in the second communication network, wherein the second request message is used for requesting to establish the emergency call.

With reference to the second aspect, in one implementation manner, the method further includes: the judging whether the second cell supports the emergency call service comprises the following steps: when the EC value of the emergency call allowed in the system information broadcasted by the second cell is 0 or when the EC value of the emergency call allowed in the system information broadcasted by the second cell is 1 and the access category of the terminal equipment belongs to the category 11-15, judging that the second cell supports the emergency call service; and when the EC value of the allowable emergency call in the system information broadcasted by the second cell is 1 and the access category of the terminal equipment does not belong to the categories 11-15, judging that the second cell does not support the emergency call service.

With reference to the second aspect and all implementations thereof, in another implementation, the carrier frequency parameter includes one carrier frequency, a plurality of carrier frequencies, or a carrier frequency range. When the carrier frequency parameter comprises a carrier frequency, the preset relationship comprises that the cell frequency is the same as the carrier frequency; when the carrier frequency parameter comprises a plurality of carrier frequencies, the preset relationship comprises that the cell frequency is one of the plurality of carrier frequencies; when the carrier frequency parameter comprises a carrier frequency range, the predetermined relationship comprises the cell frequency being within a carrier frequency range.

With reference to the second aspect and all implementation manners thereof, in another implementation manner, the determining whether the second cell supports the emergency call service includes: and judging whether the second cell supports the emergency call service according to the stored historical information, wherein the historical information is the information of whether the second cell supports the emergency call service or not, which is acquired through the system information broadcast by the second cell when the terminal equipment is resided to the second cell historically.

With reference to the second aspect and all implementations of the second aspect, in another implementation, before camping on the second cell, the method further includes: and judging whether the ID of the Public Land Mobile Network (PLMN) to which the second cell belongs is the same as the ID of the first PLMN or the ID of the second PLMN, and triggering the step of residing in the second cell when the ID of the PLMN to which the second cell belongs is the same as the ID of the first PLMN or the ID of the second PLMN, wherein the ID of the first PLMN is the ID of the PLMN currently registered by the terminal equipment, and the ID of the second PLMN is the ID of the PLMN equivalent to the PLMN currently registered by the terminal equipment.

With reference to the second aspect and all implementations thereof, in another implementation, the method further includes: and when the ID of the PLMN to which the second cell belongs is different from the ID of the first PLMN or the ID of the second PLMN, judging whether the second cell is the cell with the strongest received signal power in the cells meeting the preset conditions in the first cell, and when the second cell is the cell with the strongest received signal power in the cells meeting the preset conditions in the first cell, triggering the step of residing in the second cell.

With reference to the second aspect and all implementation manners thereof, in another implementation manner, the first communication network is a long term evolution LTE network, and the second communication network is a global system for mobile communications GSM network.

In a third aspect, an embodiment of the present invention provides a terminal device, including: at least one transceiver configured to: sending a first request message to a network device in a first communication network, wherein the terminal device currently resides in the first communication network, and the first request message comprises emergency call indication information; receiving a first response message sent by the network equipment, wherein the first response message comprises a carrier frequency parameter in the second communication network; sending a second request message to a network device in a second communication network, wherein the second request message is used for requesting to establish an emergency call; processing circuitry coupled to the at least one transceiver, the processing circuitry configured to control the terminal device to: measuring a first cell, wherein the first cell comprises at least one cell in a second communication network, and the carrier frequency parameter of each cell in the first cell meet a preset relationship; judging whether a second cell supports the emergency call service or not, wherein the second cell is one of the first cells; and when the second cell supports the emergency call service, the second cell is resided.

With reference to the third aspect, in one implementation, the processing circuit is configured to control the terminal device to further: and when the second cell does not support the emergency call service, judging whether a third cell supports the emergency call service, wherein the third cell is a cell except the second cell in the first cell.

With reference to the third aspect and all implementations thereof, in another implementation, the carrier frequency parameter includes one carrier frequency, a plurality of carrier frequencies, or a carrier frequency range. When the carrier frequency parameter comprises a carrier frequency, the preset relationship comprises that the cell frequency is the same as the carrier frequency; when the carrier frequency parameter comprises a plurality of carrier frequencies, the preset relationship comprises that the cell frequency is one of the plurality of carrier frequencies; when the carrier frequency parameter comprises a carrier frequency range, the predetermined relationship comprises the cell frequency being within a carrier frequency range.

With reference to the third aspect and all implementation manners of the third aspect, in another implementation manner, the determining whether the second cell supports the emergency call service includes: when the EC value of the emergency call allowed in the system information broadcasted by the second cell is 0 or when the EC value of the emergency call allowed in the system information broadcasted by the second cell is 1 and the access category of the terminal equipment belongs to the category 11-15, judging that the second cell supports the emergency call service; and when the EC value of the allowable emergency call in the system information broadcasted by the second cell is 1 and the access category of the terminal equipment does not belong to the categories 11-15, judging that the second cell does not support the emergency call service.

With reference to the third aspect and all implementations thereof, in another implementation, the processing circuit is configured to control the terminal device to further: and judging whether the ID of the Public Land Mobile Network (PLMN) to which the second cell belongs is the same as the ID of the first PLMN or the ID of the second PLMN, and triggering the step of residing in the second cell when the ID of the PLMN to which the second cell belongs is the same as the ID of the first PLMN or the ID of the second PLMN, wherein the ID of the first PLMN is the ID of the PLMN currently registered by the terminal equipment, and the ID of the second PLMN is the ID of the PLMN equivalent to the PLMN currently registered by the terminal equipment.

With reference to the third aspect and all implementations thereof, in another implementation, the processing circuit is configured to control the terminal device to further: and when the ID of the PLMN to which the second cell belongs is different from the ID of the first PLMN or the ID of the second PLMN, judging whether the second cell is the cell with the strongest received signal power in the cells meeting the preset conditions in the first cell, and when the second cell is the cell with the strongest received signal power in the cells meeting the preset conditions in the first cell, triggering the step of residing in the second cell.

With reference to the third aspect and all implementation manners of the third aspect, in another implementation manner, the first communication network is a long term evolution LTE network, and the second communication network is a global system for mobile communications GSM network.

In a fourth aspect, an embodiment of the present invention provides a terminal device, including: at least one transceiver configured to: sending a first request message to a network device in a first communication network, wherein the terminal device currently resides in the first communication network, and the first request message comprises emergency call indication information; receiving a first response message sent by the network equipment, wherein the first response message comprises a carrier frequency parameter in the second communication network; sending a second request message to a network device in a second communication network, wherein the second request message is used for requesting to establish an emergency call; processing circuitry coupled to the at least one transceiver, the processing circuitry configured to control the terminal device to: measuring a first cell, wherein the first cell comprises at least one cell in a second communication network, and the carrier frequency parameter of each cell in the first cell meet a preset relationship; camping on a second cell, wherein the second cell is one of the first cells; judging whether the second cell supports the emergency call service; when the second cell does not support the emergency call service, judging whether a third cell supports the emergency call service, wherein the third cell is a cell except the second cell in the first cell; and when the third cell supports the emergency call service, reselecting to the third cell.

With reference to the fourth aspect, in an implementation manner, the determining whether the second cell supports the emergency call service includes: when the EC value of the emergency call allowed in the system information broadcasted by the second cell is 0 or when the EC value of the emergency call allowed in the system information broadcasted by the second cell is 1 and the access category of the terminal equipment belongs to the category 11-15, judging that the second cell supports the emergency call service; and when the EC value of the allowable emergency call in the system information broadcasted by the second cell is 1 and the access category of the terminal equipment does not belong to the categories 11-15, judging that the second cell does not support the emergency call service.

With reference to the fourth aspect and all implementations thereof, in another implementation, the carrier frequency parameter includes one carrier frequency, a plurality of carrier frequencies, or a carrier frequency range. When the carrier frequency parameter comprises a carrier frequency, the preset relationship comprises that the cell frequency is the same as the carrier frequency; when the carrier frequency parameter comprises a plurality of carrier frequencies, the preset relationship comprises that the cell frequency is one of the plurality of carrier frequencies; when the carrier frequency parameter comprises a carrier frequency range, the predetermined relationship comprises the cell frequency being within a carrier frequency range.

With reference to the fourth aspect and all implementation manners of the fourth aspect, in another implementation manner, the determining whether the second cell supports the emergency call service includes: and judging whether the second cell supports the emergency call service according to the stored historical information, wherein the historical information is the information of whether the second cell supports the emergency call service or not, which is acquired through the system information broadcast by the second cell when the terminal equipment is resided to the second cell historically.

With reference to the fourth aspect and all implementations thereof, in another implementation, the processing circuit is configured to control the terminal device to further: and judging whether the ID of the Public Land Mobile Network (PLMN) to which the second cell belongs is the same as the ID of the first PLMN or the ID of the second PLMN, and triggering the step of residing in the second cell when the ID of the PLMN to which the second cell belongs is the same as the ID of the first PLMN or the ID of the second PLMN, wherein the ID of the first PLMN is the ID of the PLMN currently registered by the terminal equipment, and the ID of the second PLMN is the ID of the PLMN equivalent to the PLMN currently registered by the terminal equipment.

With reference to the fourth aspect and all implementations thereof, in another implementation, the processing circuit is configured to control the terminal device to further: and when the ID of the PLMN to which the second cell belongs is different from the ID of the first PLMN or the ID of the second PLMN, judging whether the second cell is the cell with the strongest received signal power in the cells meeting the preset conditions in the first cell, and when the second cell is the cell with the strongest received signal power in the cells meeting the preset conditions in the first cell, triggering the step of residing in the second cell.

With reference to the fourth aspect and all implementation manners of the fourth aspect, in another implementation manner, the first communication network is a long term evolution LTE network, and the second communication network is a global system for mobile communications GSM network.

In the embodiment of the invention, the terminal equipment determines the cell supporting the emergency call service before determining the resident cell, and then determines the resident cell in the cell supporting the emergency call service, thereby avoiding the call establishment failure caused by the resident cell not supporting the emergency call service after residing in the cell of the traditional network and improving the success rate of establishing the emergency call in the terminal equipment CSFB.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the embodiments of the present invention will be briefly described below.

Fig. 1 is a schematic diagram of network overlay coverage according to an embodiment of the present invention;

fig. 2 is a device structure diagram of a terminal device according to an embodiment of the present invention.

Fig. 3 is a device structure diagram of another terminal device according to an embodiment of the present invention.

FIG. 4 is a flow chart of a method of call setup;

fig. 5 is a flowchart of a call setup method according to an embodiment of the present invention;

fig. 6 is a flowchart of another call setup method according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings, and it is apparent that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments.

In the following detailed description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the embodiments may be practiced. Although these embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments, it is to be understood that these examples are not limiting, that other embodiments may be utilized, and that modifications may be made by one skilled in the art without departing from the spirit and scope of the embodiments of the present invention.

Fig. 1 is a schematic diagram of network overlay coverage according to an embodiment of the present invention. Fig. 1 illustrates overlapping coverage of a 4G network 102 and a legacy network 104 in a communication system 100, in accordance with some demonstrative embodiments. The 4G network 102 may be, for example, a network based on the LTE standard, such as an LTE network or an LTE-a (english: LTE-Advanced) network, or other network that is capable of providing faster data rates than conventional networks, such as 2G and 3G networks, but does not support or adequately support voice calls. It should be understood that the 4G network is illustrated by way of example and not by way of limitation, that the 4G network 102 in embodiments of the present invention may be other networks that may exist or may be developed in the future that provide higher rates but do not support or adequately support CS voice calls, and that the legacy network 104 may be any legacy network that has a CS domain to support CS voice calls. By way of non-limiting example, legacy network 104 may be a 3G network, such as a Wideband Code Division Multiple Access (WCDMA), Time-Division Synchronous Code Division Multiple Access (TD-SCDMA), Code Division Multiple Access (CDMA) 2000 network, such as a 1xRTT network or other network standardized by 3GPP2 supporting the CS domain. As another example, the legacy network may be a 2G network, such as a GSM network.

Both the 4G network 102 and the legacy network 104 may have coverage areas represented by respective circles shown in fig. 1. The coverage areas may overlap, such as shown by the overlapping portions of the circles in fig. 1. The terminal device may operate on the 4G network 102 and the legacy network 104, and when the terminal device is in the overlapping coverage area, the terminal device may be connected to the 4G network 102 and may be capable of performing a CSFB procedure with the legacy network 104 in response to initiating a voice call.

Hereinafter, the embodiment of the present invention will be described in detail by taking the 4G network as an LTE network and the conventional network as a GSM network as an example.

Fig. 2 shows an apparatus configuration diagram of a terminal device. It should be understood that the components, devices, or elements shown in fig. 2 and described below with respect to fig. 2 may not be necessary, and thus some of them may be omitted in certain embodiments. Furthermore, some embodiments may include other or different components, devices, or elements than those shown in fig. 2 and described with respect to fig. 2.

In some example embodiments, terminal device 200 may include processing circuitry 210, and processing circuitry 210 may be configured to perform operations according to one or more example embodiments disclosed herein. That is, processing circuit 210 may be configured to perform and/or control the performance of one or more functions of terminal device 200 according to various exemplary embodiments, and thus may provide means for performing the functions of terminal device 200 according to various exemplary embodiments. The processing circuitry 210 may be configured to perform data processing, application execution, and/or other processing and management services in accordance with one or more example embodiments.

In some embodiments, terminal device 200, or one or more portions or one or more components thereof, such as processing circuit 310, may comprise one or more chipsets, each of which may comprise one or more chips. In some cases, the processing circuitry 210 and/or one or more other components of the terminal device 200 may thus be configured to implement the embodiment on a single chip or chipset. In some exemplary embodiments in which one or more components of terminal device 200 are implemented as a chipset, the chipset can enable the computing device to operate in system 200 when implemented on or operatively coupled to the computing device. For example, one or more components of the terminal device 200 may provide a chipset configured to enable the computing device to operate on the LTE network 102 and/or the legacy network 104.

In some exemplary embodiments, the processing circuit 210 may include a processor 212 and, in some embodiments, such as the embodiment shown in fig. 2, may also include a memory 214. The processing circuit 210 may communicate with or otherwise control one or more transceivers 220.

The processor 212 may be implemented in a variety of forms. For example, the processor 212 may be embodied as various processing means such as a microprocessor, a coprocessor, a controller or various other computing or processing devices including integrated circuits such as, for example, an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), some combination thereof, or the like. Although shown as a single processor, it is to be understood that the processor 212 may comprise a plurality of processors. The plurality of processors may be in operative communication with each other and may be collectively configured to perform one or more functions of terminal device 200 as described herein. In some example embodiments, the processor 212 may be configured to execute instructions that may be stored in the memory 214 or may otherwise be accessible to the processor 312. Thus, whether configured by hardware or a combination of hardware and software, the processor 212, when configured accordingly, is capable of performing operations in accordance with various embodiments.

In some example embodiments, memory 214 may include one or more memory devices. The memory 214 may include fixed and/or removable memory devices. In some embodiments, the memory 214 may provide a non-transitory computer-readable storage medium that may store computer program instructions executable by the processor 212. In this regard, the memory 214 may be configured to store information, data, applications, instructions or the like for enabling the terminal device 200 to perform various functions in accordance with one or more exemplary embodiments. In some embodiments, the memory 314 may be in communication with the processor 212, or one or more of the transceivers 220, via one or more buses, for transferring information between components of the terminal device 200.

The terminal device 200 may also include one or more transceivers 220. The one or more transceivers 220 may enable the terminal device 200 to transmit wireless signals to and receive signals from one or more wireless networks, such as the LTE network 102 and the legacy network 104. As such, the one or more transceivers 220 may be configured to support any type of cellular or other wireless communication technology that may be implemented by the LTE network 102 and/or the legacy network 104. In some example embodiments, the one or more transceivers 220 may include a single transceiver configured to enable the terminal device 200 to connect to both the LTE network 102 and the legacy network 104. Alternatively, in some example embodiments, the one or more transceivers 220 may include a first transceiver configured to enable the terminal device 200 to connect to the LTE network 102 and a second transceiver configured to enable the terminal device 200 to connect to the legacy network 104.

Fig. 3 shows an apparatus configuration diagram of another terminal device. As shown, on the basis of fig. 2, the processor 212 further includes: GSM CM module 2120, GSM MM module 2121, LTE module 2122, GSM PHY module 2123, and GSM AS module 2124, which may be computer program instructions executed by processor 212 to implement the method flow in the embodiment of the present invention.

Fig. 4 shows a flow chart of a method of call setup, comprising:

s401: the terminal equipment sends an Extended Service Request message (Extended Service Request) to the network equipment in the first communication network;

the terminal device resides in a cell in the first communication network when transmitting an extended Service request message, where the extended Service request message includes an emergency call indication (Service type) and the extended Service request message may be transmitted to a network device in the first communication network by an LTE module of the terminal device. Illustratively, the first communication network may be an LTE network.

S402: a network device in a first communication network sends a radio resource control Connection Release message (RRC Connection Release) to a terminal device;

the rrc connection release message is used to instruct the terminal device to redirect to the CS network in the second communication network, and includes a carrier frequency parameter (RedirectedCarrierInfo). The carrier frequency parameter may include a carrier frequency, a plurality of carrier frequencies, or a range of carrier frequencies. Illustratively, the carrier frequency parameter is a GERAN (english: GSM EDGE Radio Access Network) carrier frequency parameter, and the second communication Network may be a GSM Network.

S403: an LTE module of the terminal equipment sends a redirection instruction (ID _ LRRC _ GRR _ REDIRECTED _ REQ) to a GSM Access layer (English: Access Stratum, AS for short) module of the terminal equipment;

the redirection instruction comprises a carrier frequency parameter received from the network device, and the redirection instruction is used for instructing a GSM AS module of the terminal device to redirect to a GSM network.

S404: a GSM AS module of the terminal equipment sends a measurement instruction (EVT _ MPH _ RXLEV _ REQ) to a GSM Physical Layer (PHY) module of the terminal equipment;

the measurement instruction comprises a carrier frequency parameter in the redirection instruction and a preset threshold, and the measurement instruction is used for instructing the GSM PHY module to measure the GSM cell.

S405: a GSM PHY module of the terminal equipment measures at least one GSM cell;

the GSM PHY module measures at least one GSM cell with a cell carrier frequency (hereinafter, referred to as a cell frequency) and a carrier frequency parameter satisfying a preset relation. When the carrier frequency parameter comprises a carrier frequency, the preset relationship comprises that the cell frequency is the same as the carrier frequency; when the carrier frequency parameter comprises a plurality of carrier frequencies, the preset relationship comprises that the cell frequency is one of the plurality of carrier frequencies; when the carrier frequency parameter comprises a carrier frequency range, the predetermined relationship comprises the cell frequency being within the carrier frequency range.

If no GSM cell is measured at the carrier frequency satisfying the preset relationship with the carrier frequency parameter in step S404 after the GSM PHY module measures the GSM cell, the GSM PHY module may measure the GSM cell according to GERAN carrier frequency information preconfigured in the terminal device, or measure the GSM cell according to historical GERAN carrier frequency information stored in the terminal device, to obtain GSM cell information satisfying the preset condition.

S406: the GSM PHY module of the terminal equipment sends the information of the GSM cell meeting the preset conditions to the GSM AS module of the terminal equipment after the measurement;

wherein, for example, the preset condition includes: the power of the cell received signal is greater than or equal to the preset threshold value sent to the GSM PHY module by the GSM AS module in S404.

S407: a GSM AS module of the terminal equipment determines a resident cell from GSM cells which are sent by a GSM PHY module and meet preset conditions;

the GSM AS module determines the resident cell by the following method:

firstly, a GSM AS module sequentially judges whether a GSM Cell meeting preset conditions is a Suitable Cell (Suitable Cell);

there may be only one or more GSM cells satisfying the predetermined condition. If there is only one, the GSM AS module directly judges whether the GSM cell is a suitable cell, specifically, the GSM AS module judges whether the ID of the PLMN to which the GSM cell belongs is the same AS the ID of the PLMN currently registered by the terminal device or the ID of the equivalent PLMN according to the information sent by the GSM PHY module, and if so, judges that the GSM cell is a suitable cell and takes the GSM cell AS a resident cell; if not, the GSM Cell is determined to be an Acceptable Cell (Acceptable Cell). Wherein the equivalent PLMN and the PLMN the terminal equipment is currently registered in belong to the same operator.

When there are multiple GSM cells meeting the preset conditions, the GSM AS module judges one by one according to the method, and then selects any one cell from the judged suitable cells or selects the cell with the strongest received signal power AS the resident cell.

Secondly, when there is no suitable cell in the GSM cells meeting the preset condition, the GSM AS module selects any one cell from the acceptable cells or selects the cell with the strongest received signal power AS the resident cell.

The reason why the suitable cell is preferentially selected as the camping cell is that the terminal device can only make an emergency call in the acceptable cell and cannot make other services after the emergency call.

S408: a GSM AS module of the terminal equipment sends a cell residence instruction (ID _ MPH _ CAMP _ SCELL _ REQ) to a GSM PHY module so AS to instruct the GSM PHY module to control the terminal equipment to reside in a selected cell;

s409: the GSM PHY module sends a cell residence confirmation (ID _ MPH _ CAMP _ SCELL _ CNF) to the GSM AS module;

s410: the GSM AS module sends a redirection acknowledgement (ID _ LRRC _ GRR _ REDIRECTED _ CNF) to the LTE module;

s411: the GSM AS module sends a cell information indication (GRRMM _ SYS _ INFO _ IND) to a GSM Mobility Management (MM) module of the terminal equipment;

the cell information indication comprises information of a resident cell, and the information of the resident cell comprises an Access-Restriction-Emergency-Service (ACCESS-Restriction-Emergency-Service) indication of the cell.

S412: a GSM Connection Management (CM) module of the terminal equipment sends a Connection Management service REQUEST instruction (ID _ NAS _ CM _ SERV _ REQUEST) to a GSM MM module;

the connection management service request instruction includes an emergency-call-establishment instruction (emergency-call-establishment) for requesting establishment of an emergency call.

S413: the GSM MM module sends a wireless resource connection establishment request instruction (RRMM _ EST _ REQ) to the GSM AS module;

the radio resource connection establishment request instruction includes an emergency-call-establishment instruction (emergency-call-establishment) for requesting establishment of an emergency call.

S414: the GSM AS module sends a wireless resource connection establishment confirmation (RRMM _ EST _ CNF) to the GSM MM module;

the radio resource connection establishment confirmation comprises information that the establishment result is forbidden access (result) and is used for indicating that the current resident cell does not support the emergency call.

S415: the GSM MM module sends a wireless resource and mobility management SESSION termination notification instruction (RRMM _ END _ SESSION _ NOTIFY) to the GSM AS module;

the radio resource and mobility management termination session notification instruction is used for instructing the terminal device to terminate the session. From the user experience, the terminal device hangs up the call directly, resulting in a dropped call.

Fig. 5 is a call setup method according to an embodiment of the present invention, and as shown in the figure, S501-S502 in fig. 5 are the same as S401-S402 and S504-S506 in fig. 4 and its corresponding embodiment, and S404-S406 in fig. 4 and its corresponding embodiment, except that:

in S503, the LTE module of the terminal device sends a redirection instruction (ID _ LRRC _ GRR _ REDIRECTED _ REQ) to the GSM access layer module of the terminal device;

the redirection instruction includes, in addition to the carrier frequency parameter received from the network device, an emergency call indication, such as a CS emergency call indication, indicating that the type of traffic to be performed is an emergency call.

After the GSM PHY module of the terminal device sends the information of the GSM cell satisfying the preset condition to the GSM AS module of the terminal device after the measurement, the GSM AS module does not immediately determine a resident cell from the GSM cells satisfying the preset condition, but first sequentially determines whether the GSM cells satisfying the preset condition support the emergency call service (the determination order is not limited in the embodiment of the present invention). For example, AS shown in S507, the GSM AS module determines whether one of the GSM cells meeting the preset condition supports the emergency call service, where the determining method includes, but is not limited to:

and the GSM AS module judges whether the current GSM cell supports the emergency call service according to the received system information broadcasted by the current GSM cell. The GSM AS module reads the value of an 'Emergency Call allowed' (EC) field in a random Access channel Control parameter (RACH Control Parameters) 1,2,2bis,3 or 4 of a SYSTEM INFORMATION TYPE (System INFORMATION TYPE) broadcasted by the current GSM cell, and judges that the current GSM cell supports Emergency Call service when the EC value is 0 or 1 and the Access TYPE (Access class) of the terminal equipment belongs to the TYPE 11-15; when the EC value is 1 and the access category of the terminal device does not belong to category 11-15, it is determined that the current GSM cell does not support the Emergency call service (For example, the access category of the terminal device may refer to relevant standards of GSM and LTE, For example, the access category 11 is PLMN usage (For PLMN Use), the access category 12 is Security Services (Security Services), the access category 13 is Public facilities (Public Utilities), the access category 14 is Emergency Services (Emergency Services), and the access category 15 is PLMN Staff (PLMN Staff), which is not described in detail in the embodiments of the present invention.

If the current GSM cell supports the emergency call service, the GSM AS module continues to perform S508a, i.e. determines the cell to camp on. When determining the resident cell, firstly, the GSM AS module determines whether the current GSM cell is a suitable cell. For example, the GSM AS module determines, according to the information sent by the GSM PHY module, whether the ID of the PLMN to which the current GSM cell belongs is the same AS the ID of the PLMN currently registered by the terminal device or the ID of the equivalent PLMN, and if so, determines that the GSM cell is a suitable cell, and takes the GSM cell AS a residential cell; if not, the GSM Cell is determined to be an Acceptable Cell (Acceptable Cell). Wherein the equivalent PLMN and the PLMN the terminal equipment is currently registered in belong to the same operator. When the GSM AS module determines that the current GSM cell is a suitable cell, the current GSM cell may be determined AS the resident cell, and when the GSM AS module determines that the current GSM cell is an acceptable cell, the GSM AS module continues to execute S508b, that is, determines whether the next GSM cell supports the emergency call service. When the preset conditions are met and no suitable cell exists in the GSM cells supporting the emergency call service, or the GSM AS modules are acceptable cells, any one of the GSM AS modules or the cell with the strongest received signal power is selected AS the resident cell.

If the current GSM cell does not support the emergency call service, the GSM AS module continues to execute S508b, that is, determines whether the next GSM cell supports the emergency call service. If none of the GSM cells satisfying the preset condition supports the emergency call service, S504-S507 are executed again.

Optionally, when determining that the current GSM cell supports the emergency call service, the GSM AS module omits a step of determining whether the current GSM cell is a suitable cell, and directly determines the current GSM cell AS the camped cell. Under the condition, the terminal equipment does not need to read the system information of the current GSM cell to acquire the PLMN ID of the current GSM cell, so that the time for determining the resident cell can be saved, and the resident speed is accelerated.

Next, S509-S514 are the same AS S408-S413 in fig. 4 and its corresponding embodiment, except that, AS shown in S515, the GSM AS module of the terminal device sends a radio resource connection establishment confirmation to the GSM MM module, where the establishment result is an establishment success (EST success) message for indicating that the radio resource connection is successfully established for the emergency call in the currently camped cell. As shown in S516, the GSM MM module sends a connection management Service Request (CM Service Request) to a network device in the GSM network, requesting to establish an emergency call. The subsequent UE successfully establishes an emergency call in the GSM network.

Fig. 6 is another call setup method according to an embodiment of the present invention, AS shown in fig. 6, S601-S613 in fig. 6 is the same AS S401-S413 in fig. 4 and its corresponding embodiment, except that, AS shown in S614, the GSM AS module of the terminal device determines whether the current camped cell supports the emergency call service after receiving the radio resource connection setup request instruction sent by the GSM MM module. The GSM AS module may determine whether the current resident cell supports the emergency call service in the following two ways:

1. and the GSM AS module judges whether the current resident cell supports the emergency call service according to the received system information broadcasted by the current resident cell. The GSM AS module reads the value of an 'Emergency Call allowed' (EC) field in a random Access channel Control parameter (RACH Control Parameters) 1,2,2bis,3 or 4 of a SYSTEM INFORMATION TYPE (System INFORMATION TYPE) broadcast by a current resident cell, and judges that the current resident cell supports Emergency Call service when the EC value is 0 or 1 and the Access TYPE (Access class) of a terminal device belongs to the TYPE 11-15; when the EC value is 1 and the access category of the terminal equipment does not belong to the category 11-15, judging that the current resident cell does not support the emergency call service;

2. when the terminal device has been camped in the current camped cell historically and has saved the information (Access-triggering-Emergency-Service) whether the current camped cell supports the Emergency call Service, it can be determined whether the current camped cell supports the Emergency call Service by looking at the information.

When the GSM AS module determines that the current resident cell does not support the emergency call service, AS shown in S615, the GSM AS module determines a new resident cell. The GSM AS module may determine a new camping cell in the GSM cell satisfying the preset condition acquired in S606, or a new GSM cell satisfying the preset condition acquired by re-executing S604-S606, AS described in S508a, and perform the following steps:

s616: a GSM AS module of the terminal equipment sends a cell residence instruction to a GSM PHY module so AS to indicate the GSM PHY module to control the terminal equipment to reside in the selected cell;

s617: the GSM PHY module sends a cell residence confirmation to the GSM AS module;

s618: a GSM AS module of the terminal equipment sends a wireless resource connection establishment confirmation to a GSM MM module, wherein the establishment result is information of successful establishment and is used for indicating that the wireless resource connection is successfully established for the emergency call in the current resident cell;

s619: the GSM MM module sends a connection management service request to network equipment in a GSM network to request the establishment of an emergency call. The subsequent UE successfully establishes an emergency call in the GSM network.

In the embodiment of the invention, before the terminal equipment establishes the emergency call, whether the current resident cell supports the emergency call service is judged, and when the current resident cell is found not to support the emergency call service, a new resident cell supporting the emergency call service is determined again, so that the success rate of establishing the emergency call in the terminal equipment CSFB is improved.

In this embodiment of the present invention, the terminal device 200 shown in fig. 2 or fig. 3 may execute the call setup method shown in fig. 5, where the method includes:

at least one transceiver 220 configured to:

sending a first request message to a network device in a first communication network, wherein the terminal device currently resides in the first communication network, and the first request message comprises emergency call indication information; optionally, this step is performed by LTE module 2122 in processor 212 triggering transceiver 220;

receiving a first response message sent by the network equipment, wherein the first response message comprises a carrier frequency parameter;

sending a second request message to a network device in a second communication network, wherein the second request message is used for requesting to establish an emergency call; optionally, this step is triggered by GSM MM module 2121 in processor 212 to be performed by transceiver 220;

processing circuitry 212, the processing circuitry 212 coupled to the at least one transceiver 220, the processing circuitry 212 configured to control the terminal device to:

measuring a first cell, wherein the first cell comprises a cell in which at least one cell frequency and carrier frequency parameters in a second communication network meet a preset relationship; optionally, this step is performed by GSM PHY module 2123 in processor 212;

judging whether a second cell supports the emergency call service or not, wherein the second cell is one of the first cells; optionally, this step is performed by the GSM AS module 2124 in the processor 212;

and when the second cell supports the emergency call service, the second cell is resided.

Optionally, the processing circuit 212 is configured to control the terminal device to further:

and when the second cell does not support the emergency call service, judging whether a third cell supports the emergency call service, wherein the third cell is a cell except the second cell in the first cell. Optionally, this step is performed by the GSM AS module 2124 in the processor 212.

Optionally, the determining whether the second cell supports the emergency call service includes:

when the EC value of the allowable emergency call in the system information broadcasted by the second cell is 0, or

When the EC value of the emergency call allowed in the system information broadcasted by the second cell is 1 and the access category of the terminal equipment belongs to the categories 11-15, judging that the second cell supports the emergency call service;

and when the EC value of the allowable emergency call in the system information broadcasted by the second cell is 1 and the access category of the terminal equipment does not belong to the categories 11-15, judging that the second cell does not support the emergency call service.

Optionally, this step is performed by the GSM AS module 2124 in the processor 212.

and judging whether the ID of the Public Land Mobile Network (PLMN) to which the second cell belongs is the same as the ID of the first PLMN or the ID of the second PLMN, and triggering the step of residing in the second cell when the ID of the PLMN to which the second cell belongs is the same as the ID of the first PLMN or the ID of the second PLMN, wherein the ID of the first PLMN is the ID of the PLMN currently registered by the terminal equipment, and the ID of the second PLMN is the ID of the PLMN equivalent to the PLMN currently registered by the terminal equipment. Optionally, this step is performed by the GSM AS module 2124 in the processor 212.

and when the ID of the PLMN to which the second cell belongs is different from the ID of the first PLMN or the ID of the second PLMN, judging whether the second cell is the cell with the strongest received signal power in the cells meeting the preset conditions in the first cell, and when the second cell is the cell with the strongest received signal power in the cells meeting the preset conditions in the first cell, triggering the step of residing in the second cell. Optionally, this step is performed by the GSM AS module 2124 in the processor 212.

Optionally, the first communication network is a long term evolution LTE network, and the second communication network is a global system for mobile communications GSM network.

In this embodiment of the present invention, the terminal device 200 shown in fig. 2 or fig. 3 may further execute a call setup method shown in fig. 6, where the method includes:

at least one transceiver 220 configured to:

camping on a second cell, wherein the second cell is one of the first cells;

judging whether the second cell supports the emergency call service; optionally, this step is performed by the GSM AS module 2124 in the processor 212;

when the second cell does not support the emergency call service, judging whether a third cell supports the emergency call service, wherein the third cell is a cell except the second cell in the first cell; optionally, this step is performed by the GSM AS module 2124 in the processor 212;

and when the third cell supports the emergency call service, reselecting to the third cell.

and judging whether the second cell supports the emergency call service according to the stored historical information, wherein the historical information is the information of whether the second cell supports the emergency call service or not, which is acquired through the system information broadcast by the second cell when the terminal equipment is resided to the second cell historically. Optionally, this step is performed by the GSM AS module 2124 in the processor 212.

It will be understood by those skilled in the art that in the above embodiments, all or part may be implemented by software, hardware, firmware or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When loaded and executed on a computer, cause the processes or functions described in accordance with the embodiments of the invention to occur, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another, for example, from one website site, computer, server, or data center to another website site, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device, such as a server, a data center, etc., that incorporates one or more of the available media. The usable medium may be a magnetic medium (e.g., floppy Disk, hard Disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., Solid State Disk (SSD)), among others.

Claims

1. A method for call establishment, the method is applied to a terminal device, and is characterized by comprising the following steps:

sending a first request message to a network device in a first communication network, wherein the terminal device is currently camped on a cell in the first communication network, the first request message including emergency call indication information;

receiving a first response message sent by the network equipment, wherein the first response message comprises a carrier frequency parameter in a second communication network;

measuring a first cell, wherein the first cell comprises at least one cell in the second communication network, and the carrier frequency parameter of each cell in the first cell satisfy a preset relationship;

judging whether a second cell supports emergency call service, wherein the second cell is one of the first cells;

when the second cell supports the emergency call service, the second cell is resided;

sending a second request message to a network device in the second communication network, wherein the second request message is used for requesting to establish an emergency call;

wherein the first communication network is a long term evolution, LTE, network.

2. The method of claim 1, further comprising:

and when the second cell does not support the emergency call service, judging whether a third cell supports the emergency call service, wherein the third cell is a cell except the second cell in the first cell.

3. The method of claim 1 or 2, wherein the determining whether the second cell supports the emergency call service comprises:

When the EC value of the emergency call allowed in the system information broadcasted by the second cell is 1 and the access category of the terminal equipment belongs to categories 11-15, judging that the second cell supports the emergency call service;

and when the EC value of the allowed emergency call in the system information broadcasted by the second cell is 1 and the access category of the terminal equipment does not belong to the categories 11-15, judging that the second cell does not support the emergency call service.

4. The method of any of claims 1-3, wherein prior to camping on the second cell, further comprising:

and judging whether the ID of the Public Land Mobile Network (PLMN) to which the second cell belongs is the same as the ID of the first PLMN or the ID of the second PLMN, and triggering the step of residing in the second cell when the ID of the PLMN to which the second cell belongs is the same as the ID of the first PLMN or the ID of the second PLMN, wherein the ID of the first PLMN is the ID of the PLMN currently registered by the terminal equipment, and the ID of the second PLMN is the ID of the PLMN equivalent to the PLMN currently registered by the terminal equipment.

5. The method of claim 4, further comprising:

and when the ID of the PLMN to which the second cell belongs is different from the ID of the first PLMN or the ID of the second PLMN, judging whether the second cell is the cell with the strongest received signal power in the cells meeting the preset conditions in the first cell, and when the second cell is the cell with the strongest received signal power in the cells meeting the preset conditions in the first cell, triggering the step of residing in the second cell.

6. The method according to any of claims 1-5, wherein the second communication network is a Global System for Mobile communications (GSM) network.

7. A method for call establishment, the method is applied to a terminal device, and is characterized by comprising the following steps:

receiving a first response message sent by the network equipment, wherein the first response message comprises a carrier frequency parameter in a second communication system;

measuring a first cell, wherein the first cell comprises at least one cell in a second communication network, and the carrier frequency parameter of each cell in the first cell satisfy a preset relationship;

camping on a second cell, wherein the second cell is one of the first cells;

judging whether the second cell supports the emergency call service;

when the second cell does not support the emergency call service, judging whether a third cell supports the emergency call service, wherein the third cell is a cell which meets the preset condition except the second cell in the first cell;

reselecting to the third cell when the third cell supports the emergency call service;

wherein the first communication network is a long term evolution, LTE, network.

8. The method of claim 7, wherein the determining whether the second cell supports the emergency call service comprises:

9. The method of claim 7, wherein the determining whether the second cell supports the emergency call service comprises:

and judging whether the second cell supports the emergency call service according to the stored historical information, wherein the historical information is the information whether the second cell supports the emergency call service or not, which is acquired through the system information broadcasted by the second cell when the terminal equipment is resided to the second cell historically.

10. The method according to any of claims 7-9, wherein prior to camping on the second cell, further comprising:

11. The method of claim 10, further comprising:

12. The method according to any of claims 7-11, wherein the second communication network is a global system for mobile communications, GSM, network.

13. A terminal device, comprising:

at least one transceiver configured to:

sending a first request message to a network device in a first communication network, wherein the terminal device currently resides in the first communication network, the first request message including emergency call indication information;

sending a second request message to a network device in a second communication network, wherein the second request message is used for requesting to establish an emergency call;

processing circuitry coupled to the at least one transceiver, the processing circuitry configured to control the terminal device to:

wherein the first communication network is a long term evolution, LTE, network.

14. The terminal device of claim 13, wherein the processing circuit is configured to control the terminal device to further:

15. The terminal device according to claim 13 or 14, wherein the determining whether the second cell supports the emergency call service comprises:

16. The terminal device of any of claims 13-15, wherein the processing circuitry is configured to control the terminal device to further:

17. The terminal device of claim 16, wherein the processing circuit is configured to control the terminal device to further:

18. A terminal device according to any of claims 13-17, characterised in that the second communication network is a global system for mobile communications, GSM, network.

19. A terminal device, comprising:

at least one transceiver configured to:

camping on a second cell, wherein the second cell is one of the first cells;

judging whether the second cell supports the emergency call service;

when the second cell does not support the emergency call service, judging whether a third cell supports the emergency call service, wherein the third cell is a cell except the second cell in the first cell;

when the third cell supports the emergency call service, the third cell is resided;

wherein the first communication network is a long term evolution, LTE, network.

20. The terminal device of claim 19, wherein the determining whether the second cell supports the emergency call service comprises:

21. The terminal device of claim 19, wherein the determining whether the second cell supports the emergency call service comprises:

22. The terminal device of any of claims 19-21, wherein the processing circuitry is configured to control the terminal device to further:

23. The terminal device of claim 22, wherein the processing circuit is configured to control the terminal device to further:

24. A terminal device according to any of claims 19-23, characterised in that the second communication network is a global system for mobile communications, GSM, network.