CN115065998A - Call processing method and device - Google Patents

Abstract

The application provides a call processing method and a device, which are applied to electronic equipment, wherein the electronic equipment called or calling is resident in an LTE network after being redirected from a 5G network to the LTE network, and the method comprises the following steps: responding to the received non-access stratum safety mode command message, sending a non-access stratum safety command completion message, responding to the re-received non-access stratum safety mode command message, sending a non-access stratum safety command completion message, responding to the received trigger message of the access stratum safety mode command process, carrying out integrity protection check, and successfully establishing a call after the integrity protection check is passed. Therefore, although the non-access stratum security command completion message is retransmitted, the integrity protection can still pass and the call is successfully established, so that the success rate of call establishment after redirection in the EPS FB can be improved.

Description

Call processing method and device

The present application claims priority of chinese patent application with application number 202111583520.6 entitled "call processing method and apparatus" filed by chinese patent office at 22/12/2021, the entire contents of which are incorporated herein by reference.

Technical Field

The present application relates to the field of communications technologies, and in particular, to a call processing method and apparatus.

Background

The 5G New Radio (5G NR) technology, NR for short, is a communication technology that is gradually commercialized in a large scale. However, the current 5G network does not support voice call, so after the mobile phone resides in the NR network, if the mobile phone initiates a calling party or a called party, the mobile phone switches from the resident 5G network to a Long Term Evolution (LTE) network (also referred to as a 4G network), and performs a call service in the LTE network, which is generally referred to as Emergency procedure Fallback (EPS FB).

Disclosure of Invention

The application provides a call processing method and a call processing device, and aims to improve the success rate of call establishment after redirection in EPS FB.

In order to achieve the above object, the present application provides the following technical solutions:

a first aspect of the present application provides a call processing method, which is applied to an electronic device, where a called or calling-initiating electronic device resides in an LTE network after being redirected from a 5G network to the LTE network, and the method includes: responding to the received non-access stratum safety mode command message, sending a non-access stratum safety command completion message, responding to the re-received non-access stratum safety mode command message, sending a non-access stratum safety command completion message, responding to the received trigger message of the access stratum safety mode command process, carrying out integrity protection check, and successfully establishing a call after the integrity protection check is passed. Therefore, although the non-access stratum security command completion message is retransmitted, the integrity protection can still pass and the call is successfully established, so that the success rate of call establishment after redirection in the EPS FB can be improved.

In some implementations, the trigger message of the access stratum security mode command flow carries a first parameter, and the first parameter is related to a non-access stratum message count recorded by the core network. Performing integrity protection checks includes: and carrying out integrity protection check based on the first parameter, the non-access stratum message count recorded by the electronic equipment and the number of times of repeatedly sending the non-access stratum security command completion message. Since the number of times of repeatedly transmitting the non-access stratum security command completion message is used as a basis, the possibility of integrity protection check call can be improved.

In some implementations, performing integrity protection checking based on the first parameter, the number of non-access stratum messages recorded by the electronic device, and the number of times the non-access stratum security command completion message is repeatedly sent includes: and after the integrity protection check fails, reducing the non-access stratum message count recorded by the electronic equipment from a first value to a second value, wherein the second value represents the number of times of repeatedly sending the non-access stratum security command completion message, and performing the integrity protection check based on the first parameter and the second value. The non-access stratum message count recorded by the electronic device is reduced from a first value to a second value representing the number of times the non-access stratum security command complete message is repeatedly sent, so the possibility of failing the integrity protection check due to the repeated sending of the non-access stratum security command complete message can be eliminated.

In some implementations, reducing the non-access stratum message count recorded by the electronic device from a first value to a second value includes: in response to the value of the first integrity message authentication code not being consistent with the value of the second integrity message authentication code, decreasing the value of the non-access stratum message count from a first value to a second value, the value of the first integrity message authentication code being obtained based on the non-access stratum message count recorded by the electronic device, the value of the second integrity message authentication code being obtained based on the first parameter. Therefore, starting from the specific mode of the integrity protection check, the possibility that the integrity protection check fails due to the repeated sending of the non-access stratum security command completion message is eliminated, and the method has higher implementability and compatibility.

In some implementations, further comprising: recording the number of times a non-access stratum security command complete message is repeatedly sent, and reducing a non-access stratum message count from a first value to a second value, comprising: in response to the number of times being greater than 0, the non-access stratum message count is decreased from a first value to a second value. The number of times greater than 0 indicates that there is a case where the non-access stratum security command completion message is repeatedly transmitted, thereby avoiding the possibility of interfering with the integrity protection check not passing due to other reasons.

A second aspect of the present application provides a call processing method, which is applied to a core network device, where the core network device triggers an electronic device to redirect from a 5G network to an LTE network, and the method includes: the method comprises the steps of responding to a tracking area updating request message sent by an electronic device, sending a non-access stratum safety mode command message, responding to the condition that a non-access stratum safety command completion message is not received, sending the non-access stratum safety mode command message again, receiving the non-access stratum safety command completion message, after sending an initial context establishment request message, receiving the non-access stratum safety command completion message again, responding to the initial context establishment success message, and successfully establishing the conversation between the electronic device and an opposite terminal device. Therefore, after the initial context establishment request message is sent, the call between the electronic device and the opposite terminal device can be successfully established under the condition that the non-access stratum security command completion message is received again, and the success rate of call establishment after redirection in the EPS FB can be improved.

A third aspect of the present application provides a call processing method, which is applied to a core network device, where the core network device triggers an electronic device to redirect from a 5G network to an LTE network, and the method includes: the method comprises the steps of responding to a tracking area updating request message sent by an electronic device, sending a non-access stratum safety mode command message, responding to the condition that a non-access stratum safety command completion message is not received, sending the non-access stratum safety mode command message again, receiving the non-access stratum safety command completion message, after sending an initial context establishing request message, receiving the non-access stratum safety command completion message again, receiving an initial context establishing failure message, responding to the tracking area updating request message received again, and successfully establishing the conversation between the electronic device and an opposite terminal device. Therefore, after the initial context establishment request message is sent, the non-access stratum security command completion message is received again, and the call between the electronic device and the opposite terminal device can be successfully established under the condition that the initial context establishment failure message is received, so that the success rate of call establishment after redirection in the EPS FB can be improved.

In some implementations, before successfully establishing a call between the electronic device and the peer device in response to the received tracking area update request message again, the method further includes: in response to the initial context setup failure message, it is determined that there is a message retransmission, and the context of the electronic device is preserved. When the message retransmission is determined to exist, the context of the electronic equipment is deleted due to the message retransmission, so that the call of the electronic equipment cannot be successfully established.

In some implementations, preserving a context of an electronic device includes: the context of the electronic device is preserved in response to the message retransmission resulting in a non-consistency with the non-access stratum message count recorded by the electronic device. The inconsistency of the message count of the non-access stratum recorded by the electronic equipment caused by message retransmission is used as the basis for reserving the context, so that the possibility of interference on the situation that the call cannot be successfully established due to other reasons is avoided.

In some implementations, a process of determining that a message retransmission results in disagreement with a non-access stratum message count recorded by an electronic device includes: the method comprises the steps of obtaining a count of non-access stratum messages carried in an initial context establishing request message as a first numerical value, obtaining a count of the latest non-access stratum messages as a second numerical value, wherein the first numerical value is smaller than the second numerical value, and providing a message retransmission judging mode with high operability.

A fourth aspect of the present application provides an electronic device, comprising: a memory and at least one processor; the memory is configured to store an application program, and the at least one processor is configured to execute the application program to implement the call processing method provided by the first aspect of the present application.

A fifth aspect of the present application provides a core network device, including: a memory and at least one processor; the memory is configured to store an application program, and the at least one processor is configured to execute the application program to implement the call processing method provided in the second aspect or the third aspect of the present application.

A sixth aspect of the present application provides a computer storage medium for storing a computer program, where the computer program is specifically configured to implement the call processing methods provided in the first, second, and third aspects when executed.

A seventh aspect of the present application provides a computer program product, which when run on a computer, causes the computer to execute the call processing method provided in the first, second, and third aspects.

Drawings

FIG. 1a is an exemplary diagram of a 5G network and a 4G network covering the same area;

FIG. 1b is an exemplary diagram of a mobile phone calling under the coverage of a 4G network;

FIG. 2 is a flow chart of unsuccessful call setup after dropping from the 5G network back to the 4G network;

fig. 3 is a flowchart of a call processing method disclosed in the embodiment of the present application;

fig. 4 is a flowchart of another call processing method disclosed in the embodiment of the present application;

fig. 5 is a diagram illustrating an exemplary hardware structure of an electronic device according to an embodiment of the present disclosure;

fig. 6 is an exemplary diagram of a software framework of an electronic device disclosed in an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. The terminology used in the following examples is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the specification of this application and the appended claims, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, such as "one or more", unless the context clearly indicates otherwise. It should also be understood that in the embodiments of the present application, "one or more" means one, two, or more than two; "and/or" describes the association relationship of the associated objects, indicating that three relationships may exist; for example, a and/or B, may represent: a alone, both A and B, and B alone, where A, B may be singular or plural. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship.

Reference throughout this specification to "one embodiment" or "some embodiments," or the like, means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the present application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," or the like, in various places throughout this specification are not necessarily all referring to the same embodiment, but rather "one or more but not all embodiments" unless specifically stated otherwise. The terms "comprising," "including," "having," and variations thereof mean "including, but not limited to," unless expressly specified otherwise.

The embodiments of the present application relate to a plurality of numbers greater than or equal to two. It should be noted that, in the description of the embodiments of the present application, the terms "first", "second", and the like are used for distinguishing the description, and are not to be construed as indicating or implying relative importance or order.

In fig. 1a, the user does not make or receive a call, in which case the handset typically resides in a cell (cell) of the 5G network (although it may also reside in a cell of the LTE network). In fig. 1a, a handset is connected to a 5G base station, indicating that the handset normally resides in a cell of a 5G network. If the user wants to make or receive a call, as shown in fig. 1b, the mobile phone needs to be switched to the LTE network, i.e. the mobile phone can only make or receive a call in the LTE network. In fig. 1b, the handset is connected to the 4G base station, which indicates that the handset resides in a cell of the 4G network.

However, in the process of research, the inventor finds that the success rate of the call needs to be improved after redirection in the EPS FB flow.

Taking fig. 1b as an example, in the case of a calling party of a mobile phone, after a user dials a call, the call is not established successfully, and the user may hear a prompt tone "the user who he dials is in the middle of the call", assuming that the user does not carry the mobile phone to move for a long distance and the next call and the previous call do not exceed a certain time (e.g., 24 hours), and after the next call, the call is still established unsuccessfully, and hearing a voice prompt "the user who you dial cannot be connected for a while".

The situation of the called mobile phone is similar, the opposite-end mobile phone and the home-end mobile phone cannot successfully establish a call flow in the home call and the next call, and the opposite-end mobile phone sends a prompt tone of 'a user who calls you is in a call' or 'a user who calls you cannot be connected temporarily'.

The reason why the success rate of the call after redirection in the EPS FB is not high will be analyzed with reference to fig. 2 as follows:

fig. 2 illustrates a scenario in which the core network receives a Mobile Terminated Call (MT Call) message to trigger the EPS FB, and it can be understood that the scenario in which the core network receives a Mobile Originated Call (MO) message to trigger the EPS FB is similar.

Fig. 2 includes the following steps:

s101, after receiving a Mobile station called Call (MT Call) message or a Mobile station Originated Call (MO Call) message, a core network forwards the MT Call message or the MO Call message to an NR.

In the embodiments and drawings of the present application, NR refers to a radio access device of a 5G network.

S102, the NR sends an invite message to a User Equipment (UE) in response to the MT call message or the MO message.

The invite message usually carries a message body, which contains media information of the calling party, and may also contain other session information, such as a resource list.

S103, after receiving the invite message, the UE sends a response message 100Trying and a SESSION _ process (SESSION _ PROGRESS) message (183) to the NR respectively.

S104, NR sends the response message 100Trying and the SESSION _ PROGRESS message (183) to the core network.

S105, the core network responds to the response message 100Trying and the SESSION _ PROGRESS message (183), and sends a message triggering the EPS FB to the NR.

In some implementation manners, message interaction is performed between the core network and the NR to confirm that the EPS FB is started, and S105 is a triggering step of the message interaction, and a specific implementation manner of the message interaction may refer to a communication protocol, which is not described herein again.

S106, NR sends a redirection message to UE.

The redirection message is used to redirect the UE to the LTE network, where the redirection message includes a frequency point identifier of the LTE network, and the frequency point identifier in this embodiment takes a frequency point number as an example.

S107, the UE searches for a proper LTE cell by using the frequency point number of the LTE.

The definition of a suitable LTE cell and a specific search method may refer to a communication protocol, which is not described herein again.

S108, the UE transmits a Tracking Area Update Request message (Tracking Area Update Request Mag) to the LTE.

That is, after camping on a cell of the LTE network, the UE initiates a Tracking Area Update (TAU) procedure.

It is understood that the LTE described in the embodiments of the present application may be a wireless device in an LTE network, such as a base station.

S109, LTE sends a tracking area update request message to a core network.

In this flow, it is assumed that the UE normally interacts with the core network before this step, and in this case, the non-access stratum (NAS) COUNT (COUNT) negotiated and recorded by the UE and the core network is consistent and denoted as N, and is denoted by NAS COUNT ═ N in the dashed line in fig. 2.

According to the communication protocol, after receiving a NAS message, the core network adds 1 to the NAS COUNT recorded locally, and after receiving a NAS message and sending a feedback message of the NAS message, the UE adds 1 to the NAS COUNT recorded locally.

S110, the core network sends a NAS Security Mode Command message (Security Mode Command Msg) to the LTE.

That is, after receiving the TAU request, the network initiates a NAS Security Mode Command (SMC) flow.

For ease of understanding, in fig. 2, the security mode command message sent in this step is denoted as a first NAS security mode command message.

S111, the LTE sends an NAS security mode command message to the UE.

S112, the UE sends a Security Command Complete message (Security Command Complete Msg) to the LTE.

Accordingly, in fig. 2, the NAS security command completion message sent in this step is denoted as a first NAS security command completion message.

S113, the UE adds 1 to the NAS COUNT, namely the NAS COUNT is updated to be N + 1.

It can be understood that, after receiving the first NAS security command completion message, the base station sends the first NAS security command completion message to the core network. In some implementation manners, the NAS security command completion message is not transmitted to the core network in time due to the base station anomaly or uplink burst interference. In this case, if the NAS Security command complete message or the NAS Security command Reject message (Security command Reject Msg) is not received within a predetermined time (e.g., 1 second), the core network retransmits the NAS Security mode command message, and in this flow, it is assumed that the core network retransmits once, as in S114.

S114, the core network sends the NAS safety mode command message to the UE again through LTE.

In fig. 2, the NAS security mode command message sent in this step is denoted as a second NAS security mode command message.

In fig. 2, it is assumed that after the core network issues the second NAS security mode command message, the first NAS security command completion message is received, as in S115.

S115, the core network receives the first NAS security command completion message.

It can be understood that the NAS security command complete message received in this step is issued by the UE at S112.

S116, the core network adds 1 to the NAS COUNT, namely the NAS COUNT is updated to be N + 1.

According to the communication protocol, the core network receives the NAS security command complete message, and then performs the subsequent procedure, as in S117.

S117, the core network sends a TAU Accept message (TAU Accept) and an Initial Context Setup Request (Initial Context Setup Request) message to the LTE.

In some implementations, the initial context setup request carries a NAS COUNT of the core network, which is N +1 as described above.

In fig. 2, it is assumed that the core network receives a second NAS security command completion message after performing S117, i.e. S118.

And S118, the core network receives a second NAS security mode completion message sent by the UE through LTE.

In fig. 2, the NAS security command completion message sent in this step is denoted as a second NAS security command completion message.

It is understood that the UE sends the second NAS security mode complete message at any time between S114-S118 after receiving the second NAS security command request message at S114.

S119, the UE adds 1 to the NAS COUNT, namely the NAS COUNT is updated to be N + 2.

S120, LTE sends a trigger message of an Access Stratum (AS) SMC flow to UE, and the message carries NAS COUNT of a core network AS N + 1.

S121, the integrity protection check performed by the UE fails.

It can be understood that the integrity protection check requires using the UE to determine that the local NAS COUNT calculates the value of the integrity message authentication code (abbreviated as MAC-I) which is denoted as MAC-I1, and using the NAS COUNT of the core network to calculate the MAC-I which is denoted as MAC-I2 by using the same algorithm, and if the calculated values are the same, the integrity protection check is passed, and if the integrity protection check fails. As can be seen from fig. 2, the NAS COUNT value determined by the UE is N +2, the NAS COUNT value sent by the core network is N +1, and if the two values are not identical, the MAC-I1 is not equal to the MAC-I2, and the integrity protection check fails.

S122, the UE sends an AS Security Mode Failure (Security Mode Failure) message to the LTE.

S123, the LTE sends an Initial Context Setup Failure (Initial Context Setup Failure) message to the core network.

S124, the core network releases the Context (Context) of the UE.

Since the context is released, the UE needs to search for the cell again and initiate the TAU procedure, as follows:

s125, the UE sends a tracking area update request message to the LTE.

S126, the LTE sends a tracking area updating request message to the core network.

The core network releases the context of the UE, so the following steps are executed according to the communication protocol:

s127, the core network sends a TAU Reject (Reject) message to LTE with a cause value of #10 (privacy Reject).

Code for cause # 10.

S128, LTE sends a TAU rejection message to the UE, and the reason value is # 10.

After receiving the cause value, the UE needs to re-attach (attach) according to the protocol specification, instead of establishing a call, so that the home call fails.

As can be seen from fig. 2, the reason for the failure of the EPS FB to establish a call is that: after the redirection in the EPS FB procedure, the core network does not receive the security command completion message fed back by the UE in time due to reasons such as network poor between the UE and the LTE, so the security mode command message is retransmitted (as in S114), that is, two NAS security mode command messages are sent, so the NAS COUNT value of the UE is increased twice, but before the core network sends the initial context setup request message to the base station (as in S117), only one NAS security command completion message is received (as in S115 and S118), that is, the NAS COUNT value of the core network is increased once, so the NAS COUNT value sent by the core network is inconsistent with the NAS COUNT value recorded by the UE, and the UE fails to confirm the integrity protection check and cannot establish the call flow.

In order to solve the foregoing problems, embodiments of the present application provide a call processing method, which aims to improve a success rate of establishing a call after redirection in an EPS FB.

It can be understood that successful call refers to that whether the UE is a calling party or a called party, the UE can successfully establish a call with the UE on the opposite end.

The following embodiments of the present application apply in the following scenarios: the electronic device may access a 5G network or an LTE network. And in the case that the electronic equipment resides in the SA network of 5G, the electronic equipment is called by the opposite-end electronic equipment or initiates a call to the opposite-end electronic equipment. The 5G network may be a stand-alone network (SA) or a non-stand-alone Network (NSA).

It can be understood from fig. 2 that, since the steps involved in the embodiments of the present application are not participated by NR after the EPS FB, NR is not drawn in the drawings of the following embodiments, and the "base station" described in the drawings of the following embodiments refers to a wireless device of an LTE network.

Fig. 3 is a flowchart of a call processing method disclosed in an embodiment of the present application, including the following steps:

s201, the core network triggers and starts EPS FB in response to receiving the MT Call message or the MO Call message, and the UE resides in the LTE network.

S201 is a summary of S101 to S107, that is, specific implementation of S201 may refer to S101 to S107, which is not described herein again.

S202, the UE sends a tracking area update request message to the LTE.

S203, the UE starts message retransmission identification and records retransmission times.

It will be appreciated that a process or thread for recording the number of message retransmissions may be set up to initiate message retransmission identification.

In some implementations, the initial value of the retransmission number is 0, the UE caches a newly received NAS security mode command message (denoted as message i), and after receiving a NAS security mode command message (denoted as message i +1), compares the message i with the message i +1, if the two are the same, identifies the retransmitted message, adds 1 to the retransmission number K, and if the two are different, the K remains unchanged.

In other implementations, the UE identifies message retransmission by identifying whether a NAS Security command complete (Security command complete) message was not successfully sent. For example, a NAS security command that sequentially passes through a Packet Data Convergence Protocol (PDCP) layer and a Radio Link Control (RLC) layer is obtained to complete the numbering of a message Packet, and whether a response message of a base station to the numbered Packet is received is determined, and if so, it is determined that the numbered Packet is received by the base station, that is, the numbered Packet is successfully transmitted. If not, it means that the packet with the number is not received by the base station, that is, not successfully transmitted, nor received by the core network, and therefore, the core network retransmits the NAS security mode command message according to the communication protocol, and therefore, if the determination result is no, it is confirmed that the message retransmission is recognized, and the retransmission number K is incremented by 1. It is understood that the PDCP and RLC are only exemplary and not limiting.

It is understood that the execution interval may also be set for message retransmission identification, that is, after the UE sends out the tracking area update request message and before the TAU ACCEPT message is received, the message retransmission identification is performed, and the message retransmission identification is not performed at other times, so as to save resources of the UE.

S204, the base station sends a tracking area updating request message to the core network.

It is to be understood that the execution order of S203 and S204 is not limited.

In this embodiment, it is assumed that the UE normally interacts with the core network before the following steps, and in this case, the non-access stratum (NAS) COUNT (COUNT) negotiated and recorded by the UE and the core network is consistent and denoted as N, and is denoted by NAS COUNT ═ N at the dotted line in fig. 3.

S205, the core network sends a first NAS security mode command message to the UE through the base station.

S206, the UE sends a first NAS security command completion message to the base station.

S207, the UE adds 1 to the NAS COUNT, namely the NAS COUNT is updated to be N + 1.

In this embodiment, assuming that the core network does not receive the NAS security command complete message or the NAS security command reject message fed back by the UE for a specified time (e.g., 1 second), S208 is executed.

S208, the core network sends a second NAS security mode command message to the UE through the base station.

S209, the UE sends a second NAS security command completion message to the core network through the base station.

In this embodiment, it is assumed that the second NAS security command completion message is received after S214.

S210, the UE adds 1 to the NAS COUNT, namely the NAS COUNT is updated to be N + 2.

It can be understood that the second NAS security command complete message is a message retransmitted by the UE, so that the UE recognizes the message retransmission and performs S211.

S211, the UE records that the retransmission number K is 1.

It is assumed that after S208, the core network receives the first NAS security command completion message, and performs the following procedures:

s212, the core network receives the first NAS security command completion message.

S213, the core network adds 1 to the NAS COUNT, namely the NAS COUNT is updated to be N + 1.

S214, the core network sends a TAU Accept message (TAU Accept) and an Initial Context Setup Request (Initial Context Setup Request) message to the base station.

The initial context setup request message includes a value N +1 of NAS COUNT of the core network.

S215, the base station calculates the MAC-I (MAC-I2 for short) of the core network by using the value N +1 of the NAS COUNT of the core network.

S216, the base station sends a trigger message of an Access Stratum (AS) SMC flow to the UE, wherein the message carries MAC-I2 of the core network.

The UE performs integrity protection checking in response to the trigger message of the SMC procedure, where the integrity protection checking at least includes step S217, and possibly also includes steps that may refer to a communication protocol, which are not described herein again.

S217, the UE calculates the MAC-I (MAC-I1 for short) of the UE by using the NAS COUNT recorded by the UE.

The MAC-I is a parameter transmitted in an AS SMC flow specified by a communication protocol, so that a specific format can be referred to the communication protocol.

S218, the UE judges whether the MAC-I1 is inconsistent with the MAC-I2, if so, S219 is executed, and if not, S221 is executed.

In another implementation, the base station does not calculate MAC-I2, and the MAC-I2 is calculated by the UE, that is, the UE needs to calculate MAC-I2 in S217 if a trigger message of an Access Stratum (AS) SMC flow sent by the base station to the UE carries a value (N +1) of NAS COUNT of the core network.

S219, the UE determines whether K is greater than 0, if so, performs S220, otherwise, performs S122 and subsequent processes.

The value of K is not greater than 0, and in case that the message retransmission is not recognized, it indicates that the integrity protection check failure is not caused by the message retransmission, and therefore, the original flow is executed.

S220, after subtracting 1 from the numerical value of the NAS COUNT recorded by the UE, the UE executes S217-S218.

It is understood that the subtraction of 1 is only an example, the subtracted value may be preset, and in the case of subtraction of 1, iteration may be required for many times, but the fault tolerance is high, and in the case of subtraction of K, the iteration number can be reduced.

It is understood that if the integrity protection check failure is due to message retransmission, the MAC-I1 is consistent with MAC-I2 after performing at least one iteration, and the UE may perform the following steps:

s221, the UE sends an AS security mode completion message to the base station.

According to the communication protocol, the base station performs S222 and S223 after receiving the AS security mode complete message.

S222, the base station transmits a TAU Accept (Accept) message to the UE.

S223, the base station sends an initial context establishment success message to the core network.

S224, the UE successfully establishes a call flow with the opposite terminal equipment on the LTE.

As can be seen from the flow shown in fig. 3, in the case that the UE determines that the integrity protection check fails due to inconsistency between MAC-I1 and MAC-I2 caused by message retransmission, the locally recorded NAS COUNT value is decreased to reduce inconsistency between MAC-I1 and MAC-I2 caused by message retransmission, thereby improving the possibility of successful call establishment.

It will be appreciated that, because the most recently received message by the UE may overlap with a received message according to some communication protocols, the UE initiates identification and counting of message retransmissions in the flow illustrated in fig. 3. In case the UE stores the received message, it is also possible not to initiate the identification and counting of the message retransmission, but after S218, to identify whether there is a retransmitted message and count the number K of retransmitted messages according to the received message stored by the UE. It can be seen that the manner of identifying message retransmission shown in fig. 3 is merely one implementation and is not limiting.

Fig. 4 is a flowchart of another call processing method disclosed in the embodiment of the present application, including the following steps:

s301 core network responds to the received MT Call message or MO Call message, triggering and starting EPS FB, and residing in LTE network by UE

S301 can refer to S201, and is not described herein. S302, the UE sends a tracking area update request message to the LTE.

S303, the base station sends a tracking area updating request message to the core network.

In this embodiment, it is assumed that the UE normally interacts with the core network before the following steps, and in this case, the non-access stratum (NAS) COUNT (COUNT) negotiated and recorded by the UE and the core network is consistent and denoted as N, and is denoted by NAS COUNT ═ N at the dotted line in fig. 4.

S304, the core network sends a first NAS security mode command message to the UE through the base station.

S305, the UE sends a first NAS security command completion message to the base station.

S306, the UE adds 1 to the NAS COUNT, namely the NAS COUNT is updated to be N + 1.

In this embodiment, assuming that the core network does not receive the NAS security command complete message or the NAS security command reject message fed back by the UE for a specified time (e.g., 1 second), S307 is executed.

S307, the core network sends a second NAS security mode command message to the UE through the base station.

S308, the UE sends a second NAS safety command completion message to the base station.

S309, the UE adds 1 to the NAS COUNT, namely the NAS COUNT is updated to be N + 2.

In this embodiment, taking the example that after S309, the core network receives the first NAS security command completion message, that is, S310 and the following steps are executed.

S310, the core network receives the first NAS safety command completion message.

S311, the core network adds 1 to the NAS COUNT, namely the NAS COUNT is updated to be N + 1.

It is understood that S310 triggers S312 according to the communication protocol.

S312, the core network sends a TAU Accept message (TAU Accept) and an Initial Context Setup Request (Initial Context Setup Request) message to the base station. The initial context setup request message includes a value N +1 of NAS COUNT of the core network. S313, the base station sends a trigger message of an Access Stratum (AS) SMC flow to the UE, wherein the message carries the numerical value N +1 of the NAS COUNT of the core network.

S314, the UE confirms that the MAC-I1 is inconsistent with the MAC-I2, so that the integrity protection check fails.

It is understood that the MAC-I1 is calculated using the value of the NAS COUNT value N +2 recorded by the UE, and the MAC-I2 is calculated using the value of the NAS COUNT value N +1 of the core network. Since the value of the NAS COUNT transmitted by the core network is different from the value of the NAS COUNT recorded by the UE, the MAC-I1 is not consistent with the MAC-I2.

In other implementation manners, the MAC-I2 may also be calculated by the base station, and the calculated MAC-I is carried by the base station in the trigger message of the SMC procedure and sent to the UE, so that the UE can use the SMC directly without performing the calculation again, thereby saving resources of the UE.

In this embodiment, it is assumed that the core network receives the second NAS security command completion message after S314, i.e., S315.

S315, the core network receives the second NAS security command completion message.

S316, the core network adds 1 to the NAS COUNT, namely, the NAS COUNT is updated to be N + 2.

S317, the UE sends an AS Security Mode Failure (Security Mode Failure) message to the base station.

It is to be appreciated that, according to the communication protocol, the UE issues an AS security mode failure message in response to an integrity protection check failure. The order of execution of S315-S316 and S317 is not limited.

S318, the base station sends an Initial Context Setup Failure (Initial Context Setup Failure) message to the core network.

S319, the core network determines whether there is a message retransmission, if yes, executes S320, and if no, executes S124 and subsequent processes (not shown in fig. 3).

In some implementations, the core network stores the sent message, so the core network queries whether the sent message stores a retransmitted message, and if so, determines that there is a message retransmission.

S320, the core network determines whether the message retransmission results in inconsistency with the NAS COUNT value of the UE, if so, performs S321, otherwise, performs S124 and subsequent processes.

In some implementations, if it is determined that the value of NAS COUNT carried in the initial context setup request message is inconsistent with the value of NAS COUNT last updated (e.g., S316), it is determined that the retransmission results in inconsistency with the value of NAS COUNT of the UE.

S321, the core network reserves the context of the UE.

It can be understood that after S321 is executed, it is stated that even if the integrity protection check of the UE fails, the core network still retains the context information of the UE, and therefore, in the case that the UE initiates the TAU procedure again and tries to establish the call, since the core network retains the context information of the UE, the call of the UE is likely to be successfully established.

According to the communication protocol, after receiving the AS security mode failure message, the UE re-initiates the TAU procedure, i.e. executes S322.

S322, the UE sends a tracking area update request message to the core network via the base station.

I.e. the UE re-initiates the tracking area update request. Assuming that the network between the UE and the base station is normal at this time, after the core network sends the NAS security mode command message to the UE, the core network can receive the NAS security command completion message sent by the UE in time, and then the core network executes S323.

S323, the core network sends a tracking area update accept message to the UE via the base station.

S324, the UE establishes a call process in the LTE network.

The difference between the flow shown in fig. 4 and fig. 2 is that the operation of increasing the possibility of successful establishment of the call flow is performed on the core network side, so that the power consumption of the UE can be saved.

The call processing method described in the above embodiments may be applied to mobile phones, tablet computers, desktop computers, laptop computers, notebook computers, Ultra-mobile Personal computers (UMPC), handheld computers, netbooks, Personal Digital Assistants (PDA), wearable electronic devices, smart watches, and other electronic devices capable of supporting calls, and the aforementioned proposed UE also belongs to the electronic devices.

Fig. 5 is a composition example of an electronic device according to an embodiment of the present application. Taking a mobile phone as an example, the electronic device 300 may include a processor 310, an external memory interface 320, an internal memory 321, a display 330, a camera 340, an antenna 1, an antenna 2, a mobile communication module 350, a wireless communication module 360, and the like.

It is to be understood that the illustrated structure of the present embodiment does not constitute a specific limitation to the electronic device. In other embodiments, the electronic device may include more or fewer components than shown, or combine certain components, or split certain components, or a different arrangement of components. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

Processor 310 may include one or more processing units, such as: the processor 310 may include an Application Processor (AP), a modem processor, a Graphics Processing Unit (GPU), an Image Signal Processor (ISP), a controller, a video codec, a Digital Signal Processor (DSP), a baseband processor, and/or a neural-Network Processing Unit (NPU), etc. The different processing units may be separate devices or may be integrated into one or more processors.

It should be understood that the connection relationship between the modules illustrated in the present embodiment is only an exemplary illustration, and does not limit the structure of the electronic device 300. In other embodiments of the present application, the electronic device 300 may also adopt different interface connection manners or a combination of multiple interface connection manners in the above embodiments.

The external memory interface 320 may be used to connect an external memory card, such as a Micro SD card, to extend the storage capability of the electronic device. The external memory card communicates with the processor 310 through the external memory interface 320 to implement a data storage function. For example, files such as music, video, etc. are saved in an external memory card.

The internal memory 321 may be used to store computer-executable program code, which includes instructions. The processor 310 executes various functional applications of the electronic device 300 and data processing by executing instructions stored in the internal memory 321. The internal memory 321 may include a program storage area and a data storage area. The storage program area may store an operating system, an application program (such as a sound playing function, an image playing function, etc.) required by at least one function, and the like. The data storage area can store data (such as audio data, phone book and the like) created in the using process of the electronic device. In addition, the internal memory 321 may include a high-speed random access memory, and may further include a nonvolatile memory, such as at least one magnetic disk storage device, a flash memory device, a universal flash memory (UFS), and the like. The processor 310 executes various functional applications of the electronic device and data processing by executing instructions stored in the internal memory 321 and/or instructions stored in a memory provided in the processor.

The electronic device implements the display function through the GPU, the display screen 330, and the application processor, etc. The GPU is a microprocessor for image processing, and is connected to the display screen 330 and the application processor. The GPU is used to perform mathematical and geometric calculations for graphics rendering. The processor 310 may include one or more GPUs that execute program instructions to generate or alter display information.

The display screen 330 is used to display images, video, and the like. The display screen 330 includes a display panel. The display panel may be a Liquid Crystal Display (LCD), an organic light-emitting diode (OLED), an active-matrix organic light-emitting diode (active-matrix organic light-emitting diode, AMOLED), a flexible light-emitting diode (FLED), a miniature, a Micro-OLED, a quantum dot light-emitting diode (QLED), or the like. In some embodiments, the electronic device may include 1 or N display screens 330, N being a positive integer greater than 1.

The electronic device may implement a shooting function through the ISP, the camera 340, the video codec, the GPU, the display 330, the application processor, and the like.

The ISP is used to process the data fed back by the camera 340. For example, when a photo is taken, the shutter is opened, light is transmitted to the camera photosensitive element through the lens, the optical signal is converted into an electrical signal, and the camera photosensitive element transmits the electrical signal to the ISP for processing and converting into an image visible to naked eyes. The ISP can also carry out algorithm optimization on the noise, brightness and skin color of the image. The ISP can also optimize parameters such as exposure, color temperature and the like of a shooting scene. In some embodiments, the ISP may be provided in camera 340.

The wireless communication function of the electronic device may be implemented by the antenna 1, the antenna 2, the mobile communication module 350, the wireless communication module 360, the modem processor, the baseband processor, and the like.

The antennas 1 and 2 are used for transmitting and receiving electromagnetic wave signals. Each antenna in an electronic device may be used to cover a single or multiple communication bands. Different antennas can also be multiplexed to improve the utilization of the antennas. For example: the antenna 1 may be multiplexed as a diversity antenna of a wireless local area network. In other embodiments, the antenna may be used in conjunction with a tuning switch.

The mobile communication module 350 may provide a solution including 2G/3G/4G/5G wireless communication applied to the electronic device. The mobile communication module 350 may include at least one filter, a switch, a power amplifier, a Low Noise Amplifier (LNA), and the like. The mobile communication module 350 may receive the electromagnetic wave from the antenna 1, filter, amplify, etc. the received electromagnetic wave, and transmit the filtered electromagnetic wave to the modem processor for demodulation. The mobile communication module 350 may also amplify the signal modulated by the modem processor, and convert the signal into electromagnetic wave through the antenna 1 to radiate the electromagnetic wave. In some embodiments, at least some of the functional modules of the mobile communication module 350 may be disposed in the processor 310. In some embodiments, at least some of the functional modules of the mobile communication module 350 may be disposed in the same device as at least some of the modules of the processor 310.

In some embodiments, the electronic device initiates or receives a call request through the mobile communication module 350 and the antenna 1.

The wireless communication module 360 may provide solutions for wireless communication applied to electronic devices, including Wireless Local Area Networks (WLANs), such as wireless fidelity (Wi-Fi) networks, Bluetooth (BT), Global Navigation Satellite Systems (GNSS), Frequency Modulation (FM), Near Field Communication (NFC), Infrared (IR), and the like. The wireless communication module 360 may be one or more devices integrating at least one communication processing module. The wireless communication module 360 receives electromagnetic waves via the antenna 3, performs frequency modulation and filtering processing on electromagnetic wave signals, and transmits the processed signals to the processor 310. The wireless communication module 360 may also receive a signal to be transmitted from the processor 310, frequency-modulate and amplify the signal, and convert the signal into electromagnetic waves via the antenna 2 to radiate the electromagnetic waves.

The electronic device 300 may implement audio functions via the audio module 370, the speaker 370A, the receiver 370B, the microphone 370C, the headphone interface 370D, and the application processor. Such as music playing, recording, etc.

The audio module 370 is used to convert digital audio information into an analog audio signal output and also to convert an analog audio input into a digital audio signal. The audio module 370 may also be used to encode and decode audio signals. In some embodiments, the audio module 370 may be disposed in the processor 310, or some functional modules of the audio module 370 may be disposed in the processor 310.

The speaker 370A, also called a "horn", is used to convert the audio electrical signal into an acoustic signal. The electronic device 300 can listen to music through the speaker 370A or listen to a hands-free conversation.

The receiver 370B, also called "earpiece", is used to convert the electrical audio signal into an acoustic signal. When the electronic device 300 receives a call or voice information, it can receive voice by placing the receiver 370B close to the ear of the person.

Microphone 370C, also known as a "microphone," is used to convert sound signals into electrical signals. When making a call or transmitting voice information, the user can input a voice signal into the microphone 370C by speaking the user's mouth near the microphone 370C. The electronic device 300 may be provided with at least one microphone 370C. In other embodiments, the electronic device 300 may be provided with two microphones 370C to achieve a noise reduction function in addition to collecting sound signals. In other embodiments, the electronic device 300 may further include three, four or more microphones 370C to collect sound signals, reduce noise, identify sound sources, perform directional recording, and so on.

The headphone interface 370D is used to connect wired headphones. The headset interface 370D may be a USB interface, or may be a 3.5mm open mobile electronic device platform (OMTP) standard interface, a cellular telecommunications industry association (cellular telecommunications industry association of the USA, CTIA) standard interface.

In addition, an operating system runs on the above components. Such as an iOS operating system, an Android operating system, a Windows operating system, etc. A running application may be installed on the operating system.

Fig. 6 is a block diagram of a software structure of an electronic device according to an embodiment of the present application.

The layered architecture divides the software into several layers, each layer having a clear role and division of labor. The layers communicate with each other through a software interface. In some embodiments, the Android system is divided into four layers, an application layer, an application framework layer, an Android runtime (Android runtime) and system library, and a kernel layer from top to bottom.

The application layer may include a series of application packages. As shown in fig. 6, the application package may include applications such as camera, gallery, calendar, phone call, map, navigation, WLAN, bluetooth, music, video, short message, etc.

The application framework layer provides an Application Programming Interface (API) and a programming framework for the application program of the application layer. The application framework layer includes a number of predefined functions. As shown in FIG. 6, the application framework layers may include a window manager, content provider, phone manager, resource manager, notification manager, view system, and the like.

The window manager is used for managing window programs. The window manager can obtain the size of the display screen, judge whether a status bar exists, lock the screen, intercept the screen and the like.

Content providers are used to store and retrieve data and make it accessible to applications. The data may include video, images, audio, calls made and answered, browsing history and bookmarks, phone books, etc.

The phone manager is used to provide communication functions of the electronic device. Such as management of call status (including connection, hangup, etc.).

The resource manager provides various resources for the application, such as localized strings, icons, pictures, layout files, video files, and the like.

The notification manager enables the application to display notification information in the status bar, can be used to convey notification-type messages, can disappear automatically after a short dwell, and does not require user interaction. Such as a notification manager used to notify download completion, message alerts, etc. The notification manager may also be a notification that appears in the form of a chart or scrollbar text in a status bar at the top of the system, such as a notification of a running application in the background, or a notification that appears on the screen in the form of a dialog window. For example, prompting text information in the status bar, sounding a prompt tone, vibrating the electronic device, flashing an indicator light, etc.

The view system includes visual controls such as controls to display text, controls to display pictures, and the like. The view system may be used to build applications. The display interface may be composed of one or more views. For example, the display interface including the short message notification icon may include a view for displaying text and a view for displaying pictures.

The Android Runtime comprises a core library and a virtual machine. The Android runtime is responsible for scheduling and managing an Android system. In some embodiments of the application, the application cold start may run in the Android runtime, and the Android runtime thus obtains the optimized file state parameter of the application, and then the Android runtime may determine whether the optimized file is outdated due to system upgrade through the optimized file state parameter, and return the determination result to the application management and control module.

The core library comprises two parts: one part is a function which needs to be called by java language, and the other part is a core library of android.

The application layer and the application framework layer run in a virtual machine. And executing java files of the application program layer and the application program framework layer into a binary file by the virtual machine. The virtual machine is used for performing the functions of object life cycle management, stack management, thread management, safety and exception management, garbage collection and the like.

The system library may include a plurality of functional modules. For example: surface managers (surface managers), Media Libraries (Media Libraries), three-dimensional graphics processing Libraries (e.g., OpenGL ES), two-dimensional graphics engines (e.g., SGL), and the like.

The surface manager is used to manage the display subsystem and provide fusion of 2D and 3D layers for multiple applications.

The media library supports a variety of commonly used audio, video format playback and recording, and still image files, among others. The media library may support a variety of audio-video encoding formats, such as MPEG2, h.262, MP3, AAC, AMR, JPG, PNG, and the like.

The three-dimensional graphic processing library is used for realizing three-dimensional graphic drawing, image rendering, synthesis, layer processing and the like.

The two-dimensional graphics engine is a drawing engine for 2D drawing.

The kernel layer is a layer between hardware and software. The kernel layer at least comprises a display driver, a camera driver, an audio driver, a sensor driver and the like.

Although the Android system is taken as an example in the embodiment of the present application for description, the basic principle is also applicable to electronic devices based on operating systems such as iOS and Windows.

Claims (13)

1. A call processing method is applied to an electronic device, wherein the electronic device called or initiating a calling resides in an LTE network after being redirected from a 5G network to the LTE network, and the method comprises the following steps:

in response to receiving the non-access stratum security mode command message, sending a non-access stratum security command completion message;

in response to receiving the non-access stratum security mode command message again, sending a non-access stratum security command completion message;

responding to the received trigger message of the access layer security mode command flow, and carrying out integrity protection check;

and after the integrity protection check is passed, successfully establishing the call.

2. The method of claim 1, wherein the trigger message of the access stratum security mode command flow carries a first parameter, and the first parameter is related to a non-access stratum message count recorded by a core network;

the performing integrity protection checks includes:

and carrying out integrity protection check based on the first parameter, the non-access stratum message count recorded by the electronic equipment and the number of times of repeatedly sending non-access stratum safety command completion messages.

3. The method of claim 2, wherein performing an integrity protection check based on the first parameter, the number of non-access stratum messages recorded by the electronic device, and the number of times a non-access stratum security command complete message is repeatedly sent comprises:

after the integrity protection check fails, reducing a non-access stratum message count recorded by the electronic equipment from a first value to a second value, wherein the second value represents the number of times of repeatedly sending non-access stratum security command completion messages;

an integrity protection check is performed based on the first parameter and the second value.

4. The method of claim 3, wherein reducing the non-access stratum message count recorded by the electronic device from a first value to a second value comprises:

in response to a numerical value of a first integrity message authentication code being inconsistent with a numerical value of a second integrity message authentication code, decreasing a numerical value of the non-access stratum message count from the first numerical value to the second numerical value, the numerical value of the first integrity message authentication code being obtained based on a non-access stratum message count recorded by the electronic device, the numerical value of the second integrity message authentication code being obtained based on the first parameter.

5. The method of claim 3 or 4, further comprising:

recording the times of repeatedly sending the non-access stratum security command completion message;

said decreasing the non-access stratum message count from the first value to the second value comprises:

in response to the number of times being greater than 0, decreasing the non-access stratum message count from the first value to the second value.

6. A call processing method is applied to a core network device, the core network device triggers an electronic device to be redirected from a 5G network to an LTE network, and the method comprises the following steps:

sending a non-access stratum security mode command message in response to receiving a tracking area update request message sent by the electronic device;

in response to not receiving the non-access stratum security command completion message, re-sending the non-access stratum security mode command message;

receiving a non-access stratum security command completion message;

after sending the initial context establishment request message, receiving a non-access stratum security command completion message again;

and responding to the received initial context establishment success message, and successfully establishing the conversation between the electronic equipment and the opposite terminal equipment.

7. A call processing method is applied to a core network device, the core network device triggers an electronic device to be redirected from a 5G network to an LTE network, and the method comprises the following steps:

sending a non-access stratum security mode command message in response to receiving a tracking area update request message sent by the electronic device;

in response to not receiving the non-access stratum security command completion message, re-sending the non-access stratum security mode command message;

receiving a non-access stratum security command completion message;

after sending the initial context establishment request message, receiving a non-access stratum security command completion message again;

receiving an initial context setup failure message;

and responding to the tracking area updating request message received again, and successfully establishing the conversation between the electronic equipment and the opposite terminal equipment.

8. The method according to claim 7, further comprising, before the successfully establishing the call between the electronic device and the peer device in response to the re-received tracking area update request message, the method further comprising:

determining that there is a message retransmission in response to the initial context setup failure message;

the context of the electronic device is preserved.

9. The method of claim 8, wherein the preserving the context of the electronic device comprises:

in response to a message retransmission resulting in a non-consistency with a non-access stratum message count recorded by the electronic device, retaining a context of the electronic device.

10. The method of claim 9, wherein determining that the message retransmission results in a non-consistency with a non-access stratum message count recorded by the electronic device comprises:

acquiring a non-access stratum message count carried in the initial context establishment request message as a first numerical value;

and acquiring the latest non-access stratum message count as a second value, wherein the first value is smaller than the second value.

11. An electronic device, comprising:

a memory and at least one processor; the memory is configured to store an application program, and the at least one processor is configured to execute the application program to implement the call processing method according to any one of claims 1 to 5.

12. A core network device, comprising:

a memory and at least one processor; the memory is configured to store an application program, and the at least one processor is configured to execute the application program to implement the call processing method of any one of claims 6 or 7-10.

13. A computer storage medium storing a computer program which, when executed, implements the call processing method of any one of claims 1 to 10.

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