A method and device for transmitting system information

Abstract

A method and apparatus for transmitting system information to reduce the complexity and power consumption of system information transmission. A second terminal device sends identification information, and a first terminal device obtains the identification information sent by the second terminal device, the identification information including a first cell identifier, and the first cell identifier is a cell identifier of a resident cell or a service cell before the second terminal device and the first terminal device complete the establishment of a direct link. If the first terminal device determines that the first cell identifier is inconsistent with the second cell identifier, a first message is sent to the second terminal device, and the second terminal device receives the first message, the second cell identifier is a cell identifier of a resident cell or a service cell after the second terminal device and the first terminal device complete the establishment of a direct link, or a cell identifier of a resident cell or a service cell of the first terminal device, and the first message is part or all of the system information of the resident cell or the service cell of the first terminal device.

Description

[0001] This application is a divisional of a Chinese patent application filed with the China Patent Office on March 24, 2017, with application number 201780034344.6 and application name “A System Information Transmission Method and Device”. All contents of this application are included in the parent case. Technical Field

[0002] The present application relates to the field of communication technology, and in particular to a system information transmission method and device. Background Art

[0003] Device-to-Device (D2D) communication refers to a communication method in which the sender sends data directly to the receiver without being transferred through a base station or cellular network. A special D2D communication method is the UE-to-Network relay scenario, in which a terminal device (such as user equipment (UE)) is connected to the network through another terminal device with relay function. The former is generally called remote user equipment (Remote UE) and the latter is called relay user equipment (Relay UE).

[0004] In the UE-to-Network relay scenario, when a remote user device newly accesses a cell or the system information of the cell accessed by the remote user device changes, the remote user device needs to obtain the system information. For remote user devices within the coverage of the cell, the system information broadcast by the base station of the cell can be received through the cellular link between the remote user device and the base station. However, in this case, the remote user device needs to maintain two links, namely the cellular link and the sidelink (the link between the remote user device and the relay user device), which is more complex and consumes more power. For remote user devices outside the coverage of the cell, the system information broadcast by the base station of the cell will not be obtained.

[0005] Therefore, it is imperative to provide a system information transmission method with low complexity and low power consumption so that remote user equipment outside the cell coverage area or within the coverage area can obtain the system information broadcast by the cell base station. Summary of the invention

[0006] The embodiments of the present application provide a system information transmission method and device, so that remote user equipment outside the coverage area of ​​a cell and outside the coverage area can obtain the system information broadcast by the base station of the cell, while reducing complexity and power consumption.

[0007] In a first aspect, a system information transmission method is provided, in which a second terminal device sends identification information to a first terminal device, and the first terminal device obtains the identification information sent by the second terminal device, wherein the identification information includes a first cell identification. If the first terminal device determines that the first cell identification included in the obtained identification information is inconsistent with the second cell identification, a first message is sent to the second terminal device, and the second terminal device receives the first message sent by the first terminal device, wherein the first message includes part or all of the system information sent by a network device to which a resident cell or a serving cell of the first terminal device belongs.

[0008] Through the above method, no matter the second terminal device is outside the range of the resident cell or service cell after the second terminal device establishes a direct link with the first terminal device, or is within the range of the resident cell or service cell after the second terminal device establishes a direct link with the first terminal device, the second terminal device can obtain the system information sent by the network device to which the resident cell or service cell belongs after the second terminal device establishes a direct link with the first terminal device. Since in the above method the second terminal device does not need to interact with the network device to which the resident cell or service cell belongs after the second terminal device establishes a direct link with the first terminal device, the second terminal device can obtain the system information sent by the network device to which the resident cell or service cell belongs after the second terminal device establishes a direct link with the first terminal device. Therefore, the second terminal device no longer needs to maintain the communication link between the network device to which the resident cell or service cell belongs after the direct link is established with the first terminal device, thereby reducing complexity and power consumption.

[0009] The first cell identifier of the identification information is the cell identifier of the resident cell or the serving cell before the second terminal device establishes a direct connection with the first terminal device. The second cell identifier is the cell identifier of the resident cell or the serving cell after the second terminal device establishes a direct connection with the first terminal device, or the cell identifier of the resident cell or the serving cell of the first terminal device.

[0010] In one possible implementation, the identification information also includes a first system information value identifier. If the first terminal device determines that the first cell identifier is consistent with the second cell identifier, and the first system information value identifier is different from the second system information value identifier, the first message is sent to the second terminal device. By carrying the first system information value identifier in the identification information, when the first terminal device determines that the resident cell or service cell of the second terminal device after establishing a direct connection with the first terminal device is the same, the first terminal device can further determine whether it is necessary to send the first message to the second terminal device based on the first system information value identifier and the second system information value identifier included in the identification information, so that the second terminal device can obtain system information when the resident cell or service cell where the second terminal device is located has not changed but the system information in the cell has changed.

[0011] Among them, the first system information value identifier is the system information value identifier of the resident cell or service cell before the second terminal device establishes a direct connection with the first terminal device, and the second system information value identifier is the system information value identifier of the resident cell or service cell of the first terminal device.

[0012] In another possible implementation, the system information included in the first message may be part of the system information of the resident cell or service cell of the first terminal device, and the part of the system information may include basic system information required by the second terminal device, and the basic system information refers to the system information required by each second terminal device in the resident cell or service cell.

[0013] In another possible implementation, the first message also includes specific system information required by the second terminal device. The specific system information can be understood as system information required by the second terminal device other than basic system information, wherein the second terminal device may not need specific system information, and the specific system information required by different second terminal devices may be the same or partially the same.

[0014] In another possible implementation, before the first terminal device sends the first message to the second terminal device, the second terminal device may send a second message to the first terminal device, wherein the second message is used to indicate specific system information required by the second terminal device. The first terminal device receives the second message sent by the second terminal device, and the second terminal device sends the specific system information required by the second terminal device to the first terminal device before the first terminal device sends the first message to the second terminal device. The first terminal device may include the specific system information required by the second terminal device in the first message sent, thereby saving signaling overhead.

[0015] In another possible implementation, after the first terminal device receives the second message sent by the second terminal device, the first terminal device may also save the specific system information required by the second terminal device, so that when the second terminal device needs to obtain the specific system information again later, the saved specific system information can be sent directly to the second terminal device.

[0016] In another possible implementation, after the first terminal device obtains the identification information sent by the second terminal device, if the first terminal device determines that the first cell identifier is consistent with the second cell identifier, and the first system information value identifier is the same as the second system information value identifier, then the first terminal device sends an indication information to the second terminal device to indicate that the original system information stored by the second terminal device is valid. The second terminal device receives the indication information sent by the first terminal device and determines that the system information stored by the second terminal device is valid, and there is no need to re-acquire the system information.

[0017] The original system information is the system information sent by the network equipment of the resident cell or service cell before the second terminal device establishes a direct connection with the first terminal device.

[0018] In another possible implementation, before the first terminal device obtains the identification information sent by the second terminal device, the first terminal device and the second terminal device may determine that the direct link establishment has been completed between the first terminal device and the second terminal device. The system information transmission between the first terminal device and the second terminal device is performed after a direct link is established between the first terminal device and the second terminal device, and does not involve changes to the signaling and protocol in the process of establishing the direct link. Therefore, the system information transmission method can be applied not only to the 3GPP access technology of the first terminal device and the second terminal device, that is, the scenario where the short-distance communication link is a side link, but also to the scenario where the first terminal device and the second terminal device are non-3GPP access technologies, that is, the short-distance communication link uses Bluetooth or Wifi technology.

[0019] In another possible implementation, the identification information may be carried in a direct link request message sent by the second terminal device to the first terminal device. By carrying the identification information in the direct link request message sent by the second terminal device, signaling overhead may be saved.

[0020] In another possible implementation, if the second terminal device has special business requirements and needs to send a second message and identification information to the first terminal device, the second terminal device may carry both the identification information and the second message in a direct connection request message sent by the second terminal device to the first terminal device to save signaling overhead.

[0021] In another possible implementation, if the first terminal device sends indication information to the second terminal device to indicate that the original system information stored in the first terminal is valid, the indication information can be carried in the direct link acceptance message sent by the first terminal device to the second terminal device to save signaling overhead.

[0022] In another possible implementation, the first terminal device may carry the first message containing the system information sent to the second terminal device in the direct link acceptance message sent by the first terminal device to the second terminal device, so as to save signaling overhead.

[0023] In a second aspect, a system information transmission method is provided, in which a first terminal device may send identification information to a second terminal device, the identification information including a second cell identifier and may also include a second system information value identifier. The second terminal device determines whether it is necessary to request system information from the second terminal device based on the received second cell identifier and the second system information value identifier; if the first cell identifier and the second cell identifier are inconsistent, or the first cell identifier and the second cell identifier are consistent and the first system information value identifier is different from the second system information value identifier, the second terminal device sends a request message to the first terminal device, the request message requests the first terminal device to send system information to the second terminal device. If the first terminal device receives the request message sent by the second terminal device, the first terminal device sends a first message to the second terminal device. If the first terminal device receives the second message sent by the second terminal device, the first terminal device may also save specific system information of each second terminal device.

[0024] The identification information may be sent after the direct link is established between the first terminal device and the second terminal device, or may be included in a direct link acceptance message sent by the first terminal device to the second terminal device.

[0025] The second terminal device may send the request message and the second message in one message or send them separately.

[0026] In a third aspect, a system information transmission device is provided, which has the function of implementing the first terminal device in the method of the first aspect, and the function can be implemented by hardware, or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions. The module can be software and / or hardware.

[0027] In one possible design, the system information transmission device includes a receiving unit, a processing unit and a sending unit. The functions of the receiving unit, the processing unit and the sending unit may correspond to the steps of each method and will not be described in detail here.

[0028] In a fourth aspect, a system information transmission device is provided, which has the function of implementing the second terminal device in the method of the first aspect, and the function can be implemented by hardware, or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions. The module can be software and / or hardware.

[0029] In a possible design, the system information transmission device includes a sending unit and a receiving unit. The functions of the sending unit and the receiving unit may correspond to the steps of each method and will not be described in detail here.

[0030] In a fifth aspect, a first terminal device is provided, the first terminal device comprising: a receiver, a transmitter, a processor and a memory. The receiver, the transmitter, the processor and the memory may be connected via a bus system. The memory is used to store a program, and the processor is used to execute the program in the memory, thereby executing the method executed by the first terminal device in the first aspect or any possible implementation of the first aspect.

[0031] In a sixth aspect, a second terminal device is provided, the second terminal device comprising: a receiver, a transmitter, a processor and a memory. The receiver, the transmitter, the processor and the memory may be connected via a bus system. The memory is used to store a program, and the processor is used to execute the program in the memory, thereby executing the method executed by the second terminal device in the first aspect or any possible implementation of the first aspect.

[0032] In a seventh aspect, an embodiment of the present application provides a communication system, which includes the first terminal device described in the fifth aspect and the second terminal device described in the sixth aspect.

[0033] In an eighth aspect, an embodiment of the present application provides a computer-readable storage medium or a computer program product for storing a computer program, which is used to execute the method in the first aspect and any possible implementation of the first aspect.

[0034] In the system information transmission method provided in the embodiment of the present application, when the first terminal device determines that it is necessary to send system information to the second terminal device, the first terminal device sends system information to the second terminal device, so that the second terminal device can obtain control signaling and user data through the first terminal device, that is, it can also obtain system information. Therefore, the second terminal device can only maintain the side link between the second terminal device and the first terminal device, without maintaining the cellular link, thereby reducing the complexity and power consumption of system information transmission, and enabling the second terminal device outside the coverage of the cell and within the coverage to obtain the system information broadcast by the base station of the cell. Furthermore, when the first terminal device determines that it is necessary to send system information to the second terminal device, the first terminal device sends system information to the second terminal device, which can reduce power consumption and signaling overhead compared to the first terminal device periodically sending all system information received from the base station to the second terminal device. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A scenario architecture diagram of the application of the system information transmission method provided in the embodiment of the present application;

[0036] Figure 2 A flowchart of an implementation of the system information transmission method provided in an embodiment of the present application;

[0037] Figure 3 Another implementation flow chart of the system information transmission method provided in the embodiment of the present application;

[0038] Figure 4 A flowchart of another implementation of the system information transmission method provided in the embodiment of the present application;

[0039] Figure 5 A flowchart of another implementation of the system information transmission method provided in the embodiment of the present application;

[0040] Figure 6 A flowchart of another implementation of the system information transmission method provided in the embodiment of the present application;

[0041] Figure 7 A flowchart of another implementation of the system information transmission method provided in the embodiment of the present application;

[0042] Figure 8 A flowchart of another implementation of the system information transmission method provided in the embodiment of the present application;

[0043] Fig. 9 A flowchart of another implementation of the system information transmission method provided in the embodiment of the present application;

[0044] Fig.10 A flowchart of another implementation of the system information transmission method provided in the embodiment of the present application;

[0045] Fig.11 A schematic diagram of the structure of a system information transmission device provided in an embodiment of the present application;

[0046] Fig.12 A schematic diagram of the structure of a first terminal device provided in an embodiment of the present application;

[0047] Fig.13 A schematic diagram of the structure of another system information transmission device provided in an embodiment of the present application;

[0048] Fig.14 A schematic diagram of the structure of a second terminal device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0049] The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0050] The system information transmission method provided in the embodiment of the present application can be applied to the communication scenario of direct communication between two devices. The devices for direct communication in the embodiment of the present application may include various handheld devices with wireless communication functions, vehicle-mounted devices, wearable devices, computing devices or other processing devices connected to a wireless modem, as well as various forms of user equipment (UE), mobile station (MS), terminal, terminal equipment, etc. For the convenience of description, the device for direct communication in the embodiment of the present application is referred to as a terminal device.

[0051] The UE-to-Network relay scenario is a typical application scenario for direct communication between two devices. Figure 1 The figure shows a schematic architecture diagram for the UE-to-Network relay scenario. Figure 1In the application scenario shown, the link between the network device and the first terminal device, and the link between the network device and the second terminal device can be called a cellular link, or an uplink or downlink, and the link between the first terminal device and the second terminal device can be called a sidelink. In the present application, the first terminal device refers to a terminal device that directly interacts with the network device, and can also be called a relay user device, and the second terminal device refers to a terminal device that communicates with the network device through the first terminal device, and can also be called a remote user device. Among them, in the existing layer 3 UE-to-Network relay communication, the control signaling of the second terminal device can interact with the network device through the cellular link, and the user data of the second terminal device can interact with the network device through the sidelink, that is, the user data between the second terminal device and the network device can be forwarded to the second terminal device through the first terminal device, or the user data between the second terminal device and the network device can be forwarded to the network device through the first terminal device. In the layer 2 UE-to-Network relay communication, the control signaling and user data of the second terminal device can interact with the network device through the sidelink.

[0052] Understandably, Figure 1 The network device involved in the invention refers to a device deployed in a wireless access network and providing wireless communication functions for a terminal, which may be a base station (BS), for example, various forms of macro base stations, micro base stations, relay stations, access points, etc. In systems using different wireless access technologies, the names of devices with base station functions may be different, for example, in a Long Term Evolution (LTE) network, it is called an evolved Node B (evolved NodeB for short: eNB or eNodeB), in a third generation 3G network, it is called a Node B, etc. For the convenience of description, the network device that communicates with the first terminal device and the second terminal device is referred to as a base station in the embodiments of the present application.

[0053] Figure 1In the application scenario shown, depending on the coverage scenario, the second terminal device can be in the cell coverage (In Coverage, IC) or out of the cell coverage (Out of Coverage, OOC), while the first terminal device must be in the cell coverage. The first terminal device and the second terminal device in the cell coverage can communicate with the base station through the cellular link; the second terminal device outside the cell coverage cannot directly communicate with the base station through the cellular link, but because the first terminal device can provide coverage for the second terminal device, the second terminal device outside the cell coverage can communicate with the base station through the first terminal device, and send uplink data to the base station through the first terminal device or receive downlink data sent by the base station through the first terminal device.

[0054] In the embodiment of the present application, in order to enable the second terminal device outside the coverage of the cell and the second terminal device within the coverage range to obtain the system information broadcast by the base station of the cell, the second terminal device can establish a direct connection with the first terminal device within the coverage range of the cell, and send the system information broadcast by the base station to the second terminal device through the first terminal device. Among them, the system information is a message that the base station periodically broadcasts to all terminal devices in the cell on the broadcast channel. The system information is divided into a master information block (Master Information Block, MIB) and multiple system information blocks (System Information Blocks, SIB). The master information block includes a limited number of the most important and most commonly used transmission parameters for reading other cell information. The system information block includes other required parameters, including SIB1-SIB20, a total of 20 system information blocks.

[0055] In an embodiment of the present application, a second terminal device that establishes a direct connection with a first terminal device that is within the coverage of a cell may be within the coverage of a resident cell or a service cell of the first terminal device, or may be outside the coverage of a resident cell or a service cell of the first terminal device, and this is not limited in the embodiment of the present application. In the present application, when a second terminal device is connected to a first terminal device, it is considered to be connected to a service cell or a resident cell of the first terminal device, wherein the service cell refers to the cell to which the terminal device is connected when the terminal device is in a Radio Resource Control (RRC) connected state. The resident cell refers to the cell in which the terminal device resides when the terminal device is in an RRC idle state.

[0056] Figure 2 FIG. 1 is a schematic diagram showing a first terminal device receiving system information through a second terminal device that has established a direct link with the second terminal device in an embodiment of the present application, wherein Figure 2It can be seen that the second terminal device can obtain control signaling and user data through the first terminal device, that is, it can also obtain system information. Therefore, the second terminal device can only maintain the side link between the second terminal device and the first terminal device, without maintaining the cellular link, thereby reducing the complexity and power consumption of system information transmission, and enabling the second terminal devices outside the coverage range of the cell and within the coverage range to obtain the system information broadcast by the base station of the cell.

[0057] It is understandable that the system information transmission method provided in the embodiment of the present application is not limited to application Figure 1 The application scenario shown may also be applied to other application scenarios of direct communication between two devices, for example, short-distance communication scenarios using technologies such as Bluetooth or Wireless Fidelity (WiFi).

[0058] The embodiment of the present application describes an implementation method of sending system information to a second terminal device through a first terminal device in combination with actual applications.

[0059] Figure 3 FIG. 1 is a flowchart of a first implementation of the system information transmission method provided in an embodiment of the present application. Figure 3 As shown, including:

[0060] S101: The second terminal device sends identification information to the first terminal device, and the first terminal device receives the identification information sent by the second terminal device.

[0061] In an embodiment of the present application, the identification information sent by the second terminal device to the first terminal device is mainly used to enable the first terminal device to determine whether it is necessary to send system information to the second terminal device. If it is determined that system information needs to be sent to the second terminal device, the system information is sent to the second terminal device to reduce signaling overhead.

[0062] In a possible implementation, the identification information sent by the second terminal device to the first terminal device includes a first cell identifier, where the first cell identifier is a cell identifier of a resident cell or a cell identifier of a service cell before the second terminal device establishes a direct connection with the first terminal device.

[0063] Among them, the cell identifier can be a cell identity identifier (IDentity, ID), such as the content of the cell identity identifier (CellIdentity) in the information element (Information Element, IE) in the system information block (SystemInformation Block, SIB) 1, the evolved cell global identifier (Evolved Cell Global Identifier, ECGI), etc. The situation outside the cell coverage range can be represented by a special cell identifier, such as an identification value of all 0s.

[0064] S102: The first terminal device determines whether it is necessary to send system information to the second terminal device.

[0065] In the embodiment of the present application, the first terminal device can determine whether it needs to send system information to the second terminal device by judging whether the first cell identifier and the second cell identifier are consistent. The second cell identifier is the cell identifier of the resident cell or the serving cell after the second terminal device and the first terminal device establish a direct link, or the cell identifier of the resident cell or the serving cell of the first terminal device.

[0066] In the embodiment of the present application, if the first terminal device determines that the first cell identifier is inconsistent with the second cell identifier, it means that the resident cell or service cell of the second terminal device has changed, and the system information needs to be re-acquired. The situation where the resident cell or service cell of the second terminal device has changed may be, but is not limited to, the following situations: when the second terminal device establishes a connection with the first terminal device, a path switch between base stations occurs, or when the second terminal device establishes a connection with the first terminal device, a reselection of the first terminal device between base stations occurs, or a second terminal device outside the cell coverage initially establishes a connection with the first terminal device.

[0067] S103: If the first terminal device determines that the first cell identifier is inconsistent with the second cell identifier, it sends a first message to the second terminal device, where the first message is part or all of the system information of the resident cell or serving cell of the first terminal device.

[0068] In the embodiment of the present application, when the first terminal device determines that the first cell identifier is inconsistent with the second cell identifier, the first terminal device sends a first message to the second terminal device. When the second terminal device needs to reacquire system information, the first message can be sent to the second terminal device to avoid sending the first message to the second terminal device when the second terminal device does not need to acquire system information, which can reduce the signaling overhead and power consumption of the first terminal device.

[0069] When the resident cell or serving cell of the second terminal device changes and system information needs to be obtained, it can be applied Figure 3 The system information transmission method execution process shown.

[0070] If the resident cell or serving cell where the second terminal device is located has not changed but the system information in the cell has changed, the second terminal also needs to obtain the system information. In this scenario, the Figure 4 The system information transmission method execution process shown.

[0071] Figure 4 FIG. 1 is a flowchart of a second implementation of the system information transmission method provided in an embodiment of the present application. Figure 4 As shown, including:

[0072] S201: The identification information sent by the second terminal device to the first terminal device includes not only the first cell identifier but also a first system information value identifier, where the first system information value identifier is the system information value identifier of the resident cell or the serving cell before the second terminal device establishes a direct connection with the first terminal device.

[0073] The system information value identifier can be understood as the IE systemInfoSIValueTag in SIB1.

[0074] S202: In addition to determining whether the first cell identifier and the second cell identifier are consistent, the first terminal device may also determine whether the first system information value identifier and the second system information value identifier are the same, wherein the second system information value identifier is the system information value identifier of the resident cell or service cell of the first terminal device.

[0075] The first terminal device can determine whether the resident cell or service cell of the second terminal device has changed by judging whether the first cell identifier and the second cell identifier are consistent. If the first cell identifier and the second cell identifier are consistent, it means that the resident cell or service cell of the second terminal device has not changed, and it can further be judged whether the system information of the resident cell or service cell of the second terminal device has been updated. The first terminal device can determine whether the system information of the resident cell or service cell of the second terminal device has been updated by judging whether the first system information value identifier and the second system information value identifier are the same, and further determine whether it is necessary to send system information to the second terminal device. When the first system information value identifier and the second system information value identifier are different, it means that the system information of the resident cell or service cell of the second terminal device has been updated, and the second terminal device needs to obtain system information, then the first terminal device sends system information to the second terminal device.

[0076] S203: The first terminal device sends a first message to the second terminal device, where the first message is part or all of the system information of the resident cell or the serving cell of the first terminal device.

[0077] Embodiments of the present application Figure 4 In the system information transmission method shown, the first terminal device sends a first message to the second terminal device when it is determined that the first cell identifier is consistent with the second cell identifier but the first system information value identifier is different from the second system information value identifier. The first message can be sent to the second terminal device when the second terminal device needs to obtain updated system information, so as to avoid sending the first message to the second terminal device when the second terminal device does not need to obtain system information, thereby reducing the signaling overhead and power consumption of the first terminal device.

[0078] In the embodiment of the present application, the first terminal device may send all the system information in the system information of the resident cell or the serving cell of the first terminal device to the second terminal device, but part of the system information in the system information of the resident cell or the serving cell of the first terminal device is not the system information needed by the second terminal device at the current moment. Therefore, if all the system information in the system information of the resident cell or the serving cell of the first terminal device is sent to the second terminal device, the signaling between the first terminal device and the second terminal device is large, and the signaling overhead is large. Therefore, in the embodiment of the present application, the first message may be part of the system information in the system information of the resident cell or the serving cell of the first terminal device, and the part of the system information may include the basic system information needed by the second terminal device. The basic system information refers to the system information needed by each second terminal device in the resident cell or the serving cell, such as the cell access-related information IEcellAccessRelatedInfo in SIB1, and part of the system information that needs to be modified by the relay user equipment and then provided to the remote user equipment for use (even in the same cell, the system information parameter values ​​used by different relay user equipment may be different), such as IE ac-BarringInfo in SIB2, or SIB14, etc.

[0079] The basic system information can also be understood as the system information that the second terminal device needs to access the cell through the first terminal device for communication. By default, each second terminal device that has established a direct link with the first terminal device needs to obtain it. Therefore, if the second terminal device needs to obtain system information, it must obtain the basic system information. The first terminal device can send the first message containing the basic system information to the second terminal device when it is determined that the system information needs to be sent to the second terminal device. If the second terminal device does not have any special services that need to be supported, it only needs to obtain the basic system information.

[0080] Since the capabilities supported by the second terminal device may be different, the service requirements may also be different, and the required system information types may also be different. For example, the system information required by the second terminal device that supports extended access class barring (EAB) is SIB14. The system information required by the second terminal device that supports Multimedia Broadcast Multicast Service (MBMS) is SIB13, SIB15, etc. The system information required by the second terminal device that supports the collaboration between the Evolved Universal Mobile Telecommunication System (UMTS) and the Evolved Universal Terrestrial Radio Access Network (E-UTRAN) and the Wireless Local Area Networks (WLAN) is SIB17, etc.

[0081] In the case where the second terminal has special needs to support services, that is, the second terminal device needs to obtain specific system information, the second terminal device may send a second message to the first terminal device, and the second message is used to indicate the specific system information required by the second terminal device. The specific system information can be understood as the system information required by the second terminal device except the basic system information, wherein the second terminal device may not need the specific system information, and the specific system information required by different second terminal devices may be the same or partially the same.

[0082] In the embodiment of the present application, the second terminal device sends a second message to the first terminal device to request specific system information required by the second terminal device. Figure 3 or Figure 4 The implementation method shown in FIG. 1 is implemented based on the implementation method shown in FIG. 1 . Figure 4 The implementation method shown is implemented as an example for explanation.

[0083] Figure 5 The figure shows a third implementation flow chart of the system information transmission method provided in the embodiment of the present application. Figure 5 S301 and S303 Figure 4 S201 and S202 are the same, except that:

[0084] S302: The second terminal device sends a second message to the first terminal device, and the first terminal device receives the second message sent by the second terminal device, where the second message is used to indicate specific system information required by the second terminal device.

[0085] S304: After receiving the second message sent by the second terminal device, the first terminal device saves the specific system information required by the second terminal device.

[0086] The first terminal device saves the specific system information required by the second terminal device, so that when the second terminal device needs to obtain the specific system information again later, the saved specific system information is directly sent to the second terminal device.

[0087] Among them, S304 is an optional step. If the first terminal device does not save the specific system information required by the second terminal device, the specific system information can be re-acquired and sent to the second terminal device.

[0088] S305: If the first terminal device determines that the first cell identifier is consistent with the second cell identifier, and the first system information value identifier is different from the second system information value identifier, a first message is sent to the second terminal device, where the first message includes basic system information required by the second terminal device and specific system information required by the second terminal device.

[0089] In an embodiment of the present application, the second terminal device sends a second message to the first terminal device to request the first terminal device to send specific system information required by the second terminal device to the second terminal device. The first terminal device can send the basic system information and specific system information required by the second terminal device to the second terminal device without sending other system information not required by the second terminal device, thereby reducing the signaling overhead between the first terminal device and the second terminal device.

[0090] In another embodiment of the present application, if the system information saved by the second terminal device is valid and there is no need to re-acquire the system information, the first terminal device may send an indication message to the second terminal device upon determining that the second terminal device does not need to obtain the system information. The indication message is used to indicate that the system information saved by the second terminal device is valid, thereby avoiding the second terminal device from obtaining duplicate system information and reducing signaling overhead.

[0091] In the embodiment of the present application, the implementation method flow of the first terminal device sending the indication information to the second terminal device indicating that the system information stored by the second terminal device is valid can be as follows: Figure 6 As shown, including:

[0092] S401: The second terminal device sends identification information to the first terminal device, where the identification information includes a first cell identifier and a first system information value identifier.

[0093] S402: The first terminal device receives identification information sent by the second terminal device, and determines whether the first cell identifier is consistent with the second cell identifier, and whether the first system information value identifier is the same as the second system information value identifier.

[0094] S403: If the first terminal device determines that the first cell identifier is consistent with the second cell identifier, and the first system information value identifier is the same as the second system information value identifier, the first terminal device sends an indication message to the second terminal device, and the indication message is used to indicate that the original system information stored by the second terminal device is valid.

[0095] The original system information is system information sent by a network device of a resident cell or a service cell before the second terminal device establishes a direct connection with the first terminal device.

[0096] In another embodiment of the present application, the various system information transmission methods involved above for sending system information from the first terminal device to the second terminal device may be performed after a direct connection has been established between the first terminal device and the second terminal device, such as Figure 7 shown. Figure 7 In the case where the first terminal device and the second terminal device determine that a direct connection has been established between the first terminal device and the second terminal device, the second terminal device sends identification information to the first terminal device, and the identification information includes the first cell identifier and may also include the first system information value identifier. If the second terminal device has special service requirements, the second terminal device may also send a second message to the second terminal device to request the required specific system information. Among them, the second terminal device may send the identification information and the second message in one message, or send them separately, which is not limited in the embodiment of the present application. The first terminal device determines whether it is necessary to send system information to the second terminal device according to the first cell identifier and the first system information value identifier; if the second terminal device sends the second message to the first terminal device, the first terminal device may also save the specific system information of each second terminal device. If the first cell identifier and the second cell identifier are inconsistent, or the first cell identifier and the second cell identifier are consistent but the first system information value identifier is different from the second system information value identifier, the first terminal device sends a first message to the second terminal device, and the first message may include the basic system information required by the second terminal device. If the second terminal device sends the second message, the first message also includes the specific system information required by the second terminal device. If the first cell identifier is consistent with the second cell identifier, and the first system information value identifier is the same as the second system information value identifier, the first terminal device sends indication information to the second terminal device, indicating that the system information originally stored by the second terminal device is valid.

[0097] This application Figure 7In the system information transmission method shown, the second terminal device receives the system information through the first terminal device, so that the second terminal device can only maintain the side link between the second terminal device and the first terminal device, without maintaining the cellular link, thereby reducing the complexity and power consumption of system information transmission, and enabling the second terminal device outside the cell coverage and outside the coverage to obtain the system information broadcast by the base station of the cell. Figure 7 The system information transmission method shown in the figure is a method for transmitting system information between the first terminal device and the second terminal device after the direct link is established between the first terminal device and the second terminal device, and does not involve changes to the signaling and protocol in the process of establishing the direct link. Therefore, the system information transmission method can be applied not only to the first terminal device and the second terminal device using the Third Generation Partnership Project (3GPP) access technology, that is, the short-distance communication link is a side link, but also to the first terminal device and the second terminal device using non-3GPP access technology, that is, the short-distance communication link uses Bluetooth or Wifi technology. Among them, the establishment of the direct link can be initiated by the second terminal device, or by the first terminal device, and the embodiments of the present application are not limited thereto.

[0098] In another embodiment of the present application, the second terminal device may carry the identification information in the direct connection request message sent to the first terminal device to further reduce the signaling overhead between the first terminal device and the second terminal device. Figure 7 The system information transmission method shown in the figure is similar to the process, the only difference is that the identification information is carried in the direct connection request message sent to the first terminal device, and there is no need to set new signaling to send identification information separately. For other implementation steps, please refer to Figure 7 The description of the system information transmission method process is not repeated here.

[0099] In another embodiment of the present application, the second terminal device carries the identification information in the direct connection request message sent to the first terminal device. After the first terminal device receives the identification information carried by the second terminal device in the direct connection request message, if the first terminal device determines that the first cell identifier is consistent with the second cell identifier, and the first system information value identifier is the same as the second system information value identifier, it is necessary to send indication information to the second terminal device to indicate that the basic system information originally stored in the second terminal device is valid. In this case, the indication information may be carried in the direct connection acceptance message sent by the second terminal device to the first terminal device to further reduce the signaling overhead between the first terminal device and the second terminal device. If the second terminal device has special service requirements, the second terminal device sends a second message to the first terminal device to request the specific system information required by the second terminal device. The first terminal device receives the second message, saves the specific system information required by the second terminal device, and sends a first message containing the specific system information to the second terminal device, such as Figure 8 shown.

[0100] In another embodiment of the present application, if the second terminal device has special service requirements and the second terminal device needs to send a second message and identification information to the first terminal device, the second terminal device may carry both the identification information and the second message in the direct link request message sent by the second terminal device to the first terminal device, and the first terminal device carries the first message or indication information sent to the second terminal device in the direct link acceptance message, wherein the first message includes the basic system information required by the second terminal device and the specific system information required by the second terminal device, so as to further reduce the signaling overhead between the first terminal device and the second terminal device. In the embodiment of the present application, the identification information and the second message are carried in the direct link request message sent by the second terminal device to the first terminal device, and the first message or indication information is included in the direct link acceptance message sent by the first terminal device to the second terminal device. The implementation process is as follows: Fig. 9 shown.

[0101] In another embodiment of the present application, the first terminal device sends identification information to the second terminal device, and the identification information includes a second cell identifier and may also include a second system information value identifier. The identification information may be sent after a direct link has been established between the first terminal device and the second terminal device, or may be included in a direct link acceptance message sent by the first terminal device to the second terminal device, which is not limited in the embodiment of the present application. The second terminal device determines whether it is necessary to request system information from the second terminal device based on the received second cell identifier and the second system information value identifier; if the first cell identifier and the second cell identifier are inconsistent, or the first cell identifier and the second cell identifier are consistent and the first system information value identifier is different from the second system information value identifier, the second terminal device sends a request message to the first terminal device, and the request message requests the first terminal device to send system information to the second terminal device. The second terminal device may send the request message and the second message in one message, or may send them separately, which is not limited in the embodiment of the present application. If the first terminal device receives the request message sent by the second terminal device, the first terminal device sends the first message to the second terminal device. If the first terminal device receives the second message sent by the second terminal device, the first terminal device may also save the specific system information of each second terminal device. The specific implementation process is as follows: Fig.10 shown.

[0102] The system information transmission method provided in the embodiment of the present application is that when the first terminal device determines that the system information needs to be sent to the second terminal device, the first terminal device sends the system information to the second terminal device. Compared with the first terminal device periodically sending all the system information received from the base station to the second terminal device, it can reduce power consumption and signaling overhead.

[0103] The above mainly introduces the solution provided by the embodiment of the present application from the perspective of the interaction between the first terminal device and the second terminal device. It is understandable that in order to realize the above functions, the first terminal device and the second terminal device include hardware structures and / or software units corresponding to the execution of each function. In combination with the units and algorithm steps of each example described in the embodiment disclosed in this application, the embodiment of the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the technical solution of the embodiment of the present application.

[0104] The embodiment of the present application can divide the functional units of the first terminal device and the second terminal device according to the above method example. For example, each functional unit can be divided according to each function, or two or more functions can be integrated into one processing unit. The above integrated unit can be implemented in the form of hardware or in the form of software functional units. It should be noted that the division of units in the embodiment of the present application is schematic and is only a logical functional division. There may be other division methods in actual implementation.

[0105] Based on the same concept as the above method embodiment, an embodiment of the present application provides a system information transmission device.

[0106] In the case of an integrated unit, Fig.11 A possible logical structure diagram of a system information transmission device is shown. The system information transmission device can be applied to a first terminal device. Fig.11 As shown, the system information transmission device 100 includes a receiving unit 101, a processing unit 102 and a sending unit 103, wherein the receiving unit 101 is used to obtain identification information sent by the second terminal device, and the identification information includes a first cell identification, and the first cell identification is the cell identification of the resident cell or service cell of the second terminal device before the direct connection is established with the first terminal device. The processing unit 102 is used to determine whether the first cell identification is consistent with the second cell identification, and the second cell identification is the cell identification of the resident cell or service cell of the second terminal device after the direct connection is established with the first terminal device, or the cell identification of the resident cell or service cell of the first terminal device. The sending unit 103 is used to send a first message to the second terminal device when the processing unit determines that the first cell identification is inconsistent with the second cell identification, and the first message is part or all of the system information in the system information of the resident cell or service cell of the first terminal device.

[0107] In a possible implementation manner, the identification information further includes a first system information value identifier, where the first system information value identifier is a system information value identifier of a resident cell or a serving cell before the second terminal device establishes a direct connection with the first terminal device.

[0108] The processing unit 102 is further configured to determine whether the first system information value identifier is the same as the second system information value identifier, where the second system information value identifier is the system information value identifier of the resident cell or the serving cell of the first terminal device.

[0109] The sending unit 103 is used to send the first message to the second terminal device when the processing unit 102 determines that the first cell identifier is consistent with the second cell identifier and the first system information value identifier is different from the second system information value identifier.

[0110] In another possible implementation, the first message includes basic system information required by the second terminal device.

[0111] In another possible implementation, the first message also includes specific system information required by the second terminal device.

[0112] The receiving unit 101 is further used to: before the sending unit 103 sends the first message to the second terminal device, receive a second message sent by the second terminal device, where the second message is used to indicate specific system information required by the second terminal device.

[0113] In another possible implementation manner, the sending unit 103 is further configured to:

[0114] When the processing unit 102 determines that the first cell identifier is consistent with the second cell identifier, and the first system information value identifier is the same as the second system information value identifier, an indication message is sent to the second terminal device, and the indication message is used to indicate that the original system information saved by the second terminal device is valid, and the original system information is the system information sent by the network device of the resident cell or service cell before the second terminal device establishes a direct connection with the first terminal device.

[0115] In another possible implementation manner, the processing unit 102 is further configured to:

[0116] Before the receiving unit 101 acquires the identification information sent by the second terminal device, it is determined that a direct connection has been established between the first terminal device and the second terminal device.

[0117] When implemented in hardware form, in the embodiment of the present application, the receiving unit 101 may be a communication interface, a receiver, a transceiver circuit, etc. The processing unit 102 may be a processor or a controller, and the sending unit 103 may be a communication interface, a transmitter, a transceiver circuit, etc. Among them, the communication interface is a general term and may include one or more interfaces.

[0118] When the receiving unit 101 is a receiver, the processing unit 102 is a processor, and the sending unit 103 is a transmitter, the system information transmission device 100 involved in the embodiment of the present application can be Fig.12 The terminal device shown. Fig.12 The terminal device shown may be a first terminal device.

[0119] Fig.12 FIG. 1 is a schematic diagram of a first terminal device 1000 provided in an embodiment of the present application. The first terminal device 1000 can be used to perform Figures 2 to 10 The execution method of the first terminal device involved in Fig.12 As shown, the first terminal device 1000 includes: a receiver 1001, a transmitter 1002, a processor 1003 and a memory 1004. The receiver 1001, the transmitter 1002, the processor 1003 and the memory 1004 can be connected via a bus system 1005.

[0120] The memory 1004 is used to store programs, instructions or codes. The processor 1003 is used to execute the program in the memory 1004 to control the receiver 1001 to obtain the identification information sent by the second terminal device, control the transmitter 1002 to send the first message to the second terminal device, and implement the steps and functions implemented by the first terminal device in the above implementation mode, which will not be repeated here. The specific implementation modes of the above receiver 1001, transmitter 1002 and processor 1003 can be referred to above. Fig.11 The specific description of the receiving unit 101, the processing unit 102 and the sending unit 103 in the implementation manner will not be repeated here.

[0121] Based on the same concept as the above method embodiment, the embodiment of the present application also provides another system information transmission device.

[0122] In the case of an integrated unit, Fig.13 Another possible logical structure diagram of the embodiment of the present application is shown. The system information transmission device can be applied to the second terminal device. Fig.13 As shown, the system information transmission device 200 includes a sending unit 201 and a receiving unit 202. The sending unit 201 is used to send the identification information to the first terminal device, and the identification information includes a first cell identification, and the first cell identification is the cell identification of the resident cell or service cell before the second terminal device establishes a direct connection with the first terminal device. The receiving unit 202 is used to receive a first message sent by the first terminal device, and the first message is part or all of the system information of the resident cell or service cell of the first terminal device, and is sent by the first terminal device when it is determined that the first cell identification is inconsistent with the second cell identification, and the second cell identification is the cell identification of the resident cell or service cell after the second terminal device establishes a direct connection with the first terminal device, or the cell identification of the resident cell or service cell of the first terminal device.

[0123] In a possible implementation, the identification information also includes a first system information value identifier, which is a system information value identifier of a resident cell or a service cell before the second terminal device establishes a direct connection with the first terminal device; the first message is sent by the first terminal device when it is determined that the first cell identifier is consistent with the second cell identifier and the first system information value identifier is different from the second system information value identifier, and the second system information value identifier is a system information value identifier of a resident cell or a service cell of the first terminal device.

[0124] In another possible implementation, the first message includes basic system information required by the second terminal device.

[0125] In another possible implementation manner, the first message further includes specific system information required by the second terminal device;

[0126] The sending unit 201 is further used to send a second message to the first terminal device before the receiving unit receives the first message sent by the first terminal device, where the second message is used to indicate specific system information required by the second terminal device.

[0127] In another possible implementation manner, the receiving unit 202 is further configured to:

[0128] After the sending unit 201 sends identification information to the first terminal device, it receives indication information sent by the first terminal device, wherein the indication information is used to indicate that the original system information saved by the second terminal device is valid, and the indication information is sent by the first terminal device when it is determined that the first cell identifier is consistent with the second cell identifier, and the first system information value identifier is the same as the second system information value identifier. The original system information is system information sent by a network device to which a resident cell or a serving cell belongs before the second terminal device establishes a direct connection with the first terminal device.

[0129] In another possible implementation manner, the sending unit 201 is further configured to:

[0130] Before sending the identification information to the first terminal device, it is determined that a direct connection has been established between the second terminal device and the first terminal device.

[0131] When implemented in hardware, in the embodiment of the present application, the sending unit 201 may be a communication interface, a transmitter, a transceiver circuit, etc. The receiving unit 202 may be a communication interface, a receiver, a transceiver circuit, etc. Among them, the communication interface is a general term and may include one or more interfaces.

[0132] When the sending unit 201 is a transmitter and the receiving unit 202 is a receiver, the system information transmission device 200 involved in the embodiment of the present application can be Fig.14 The terminal device shown. Fig.14 The terminal device shown may be a second terminal device.

[0133] Fig.14 The second terminal device 2000 provided in the embodiment of the present application is shown as a schematic diagram. The second terminal device 2000 can be used to perform Figures 2 to 10 The execution method of the second terminal device involved in Fig.14 As shown, the second terminal device 2000 includes: a transmitter 2001, a receiver 2002, a processor 2003 and a memory 2004. The transmitter 2001, the receiver 2002, the processor 2003 and the memory 2004 may be connected via a bus system 2005.

[0134] The memory 2004 is used to store programs, instructions or codes. The processor 2003 is used to execute the program in the memory 2004 to control the transmitter 2001 to send the identification information to the first terminal device, control the receiver 2002 to receive the first message sent by the first terminal device, and implement the steps and functions implemented by the second terminal device in the above implementation mode, which will not be repeated here. The specific implementation modes of the transmitter 2001, the receiver 2002 and the processor 2003 can be referred to above. Fig.13 The specific description of the sending unit 201 and the receiving unit 202 in the implementation manner will not be repeated here.

[0135] Understandably, Fig.12 and Fig.14 Only simplified designs of the first terminal device and the second terminal device are shown. In practical applications, the first terminal device and the second terminal device are not limited to the above structures, and can respectively include any number of interfaces, processors, and memories, etc. in practical applications, and all terminals that can implement the embodiments of the present application are within the protection scope of the embodiments of the present application.

[0136] It can be further understood that the system information transmission device 100 and the first terminal device 1000, as well as the system information transmission device 200 and the second terminal device 2000 involved in the embodiments of the present application can be used to implement the corresponding functions of the first terminal device and the second terminal device in the above-mentioned method embodiments of the embodiments of the present application. Therefore, for the parts where the description of the embodiments of the present application is not detailed enough, please refer to the description of the relevant method embodiments, and the embodiments of the present application will not be repeated here.

[0137] It is further understood that the processor involved in the embodiments of the present application may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0138] The memory may include a read-only memory and a random access memory, and provides instructions and data to the processor. A portion of the memory may also include a non-volatile random access memory. For example, the memory may also store information about the device type.

[0139] In addition to the data bus, the bus system may also include a power bus, a control bus, a status signal bus, etc. However, for the sake of clarity, various buses are labeled as bus systems in the figure.

[0140] In the implementation process, each step involved in the above method embodiment can be completed by an integrated logic circuit of hardware in a processor or an instruction in the form of software. The steps of the message processing method disclosed in the embodiment of the present application can be directly embodied as a hardware processor, or a combination of hardware and software modules in a processor. The software module can be located in a mature storage medium in the field such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in a memory, and the processor reads the information in the memory, and completes the steps involved in the above method embodiment in combination with its hardware. To avoid repetition, it is not described in detail here.

[0141] The present application also provides a communication system, which includes a first terminal device and a second terminal device, wherein the first terminal device may be the first terminal device provided in the above embodiment, and the second terminal device may be the second terminal device provided in the above embodiment.

[0142] The present application provides a computer-readable storage medium or a computer program product for storing a computer program for executing the system information transmission method involved in the above method embodiment.

[0143] The system information transmission method and apparatus provided in the embodiments of the present application, a first terminal device obtains identification information sent by a second terminal device, and if the first terminal device determines that the first cell identification included in the obtained identification information is inconsistent with the second cell identification, then the first terminal device sends a first message to the second terminal device. Through the above method, the second terminal device, whether it is outside the resident cell or service cell after the second terminal device establishes a direct link with the first terminal device, or within the resident cell or service cell after the second terminal device establishes a direct link with the first terminal device, can obtain the system information sent by the network device to which the resident cell or service cell belongs after the second terminal device establishes a direct link with the first terminal device. Since in the above method, the second terminal device does not need to interact with the network device to which the resident cell or service cell belongs after the second terminal device establishes a direct link with the first terminal device, it can obtain the system information sent by the network device to which the resident cell or service cell belongs after the second terminal device establishes a direct link with the first terminal device. Therefore, the second terminal device no longer needs to maintain the communication link between the network device to which the resident cell or service cell belongs after the direct link is established with the first terminal device, thereby reducing complexity and power consumption.

[0144] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the embodiments of the present application may adopt the form of complete hardware embodiments, complete software embodiments, or embodiments in combination with software and hardware. Moreover, the embodiments of the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0145] The embodiments of the present application are described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0146] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0147] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

Claims

1. A system information transmission method, characterized in that: The method is applied to a second terminal device, comprising: Receiving identification information from a first terminal device, where the identification information includes a second cell identifier, or the identification information includes a second cell identifier and a second system information value identifier; The second cell identifier is a cell identifier of a resident cell or a serving cell after the second terminal device and the first terminal device complete establishment of a direct connection, or a cell identifier of a resident cell or a serving cell of the first terminal device; The second system information value identifier is a system information value identifier of a resident cell or a serving cell of the first terminal device; Sending a second message to the first terminal device according to the identification information, where the second message is used to request the first terminal device to send system information to the second terminal device; A first message is received from the first terminal device, where the first message includes part or all of the system information of a resident cell or a serving cell of the first terminal device.

2. The method according to claim 1, characterized in that The second message indicates first system information required by the second terminal device, and the first message includes the first system information.

3. The method according to claim 2, characterized in that The first system information is system information required by the second terminal device except the second system information, and the second system information is system information required by all terminal devices in the resident cell or service cell of the second terminal device.

4. The method according to claim 1, characterized in that The sending the second message to the first terminal device according to the identification information includes: If the first cell identifier and the second cell identifier are inconsistent, or the first cell identifier and the second cell identifier are consistent and the first system information value identifier is different from the second system information value identifier, system information is requested from the first terminal device, wherein the first cell identifier is the cell identifier of the resident cell or the serving cell before the second terminal device completes the establishment of a direct connection with the first terminal device, and the first system information value identifier is the system information value identifier of the resident cell or the serving cell before the second terminal device completes the establishment of a direct connection with the first terminal device.

5. The method according to claim 1, characterized in that Before receiving the identification information from the first terminal device, the method further includes: A direct link has been established with the first terminal device.

6. The method according to any one of claims 1 to 5, characterized in that: The identification information is carried in a direct connection request message sent by the first terminal device to the second terminal device.

7. A system information transmission method, characterized in that: The method is applied to a first terminal device, comprising: Sending identification information to the second terminal device, where the identification information includes a second cell identifier, or the identification information includes a second cell identifier and a second system information value identifier; The second cell identifier is a cell identifier of a resident cell or a serving cell after the second terminal device and the first terminal device complete establishment of a direct connection, or a cell identifier of a resident cell or a serving cell of the first terminal device; The second system information value identifier is a system information value identifier of a resident cell or a serving cell of the first terminal device; receiving a second message from a second terminal device, where the second message is used to request the first terminal device to send system information to the second terminal device; A first message is sent to the second terminal device, where the first message includes part or all of the system information of the resident cell or serving cell of the first terminal device.

8. The method according to claim 7, characterized in that The second message indicates first system information required by the second terminal device, and the first message includes the first system information.

9. The method according to claim 8, characterized in that The first system information is system information required by the second terminal device except the second system information, and the second system information is system information required by all terminal devices in the resident cell or service cell of the second terminal device.

10. The method according to claim 7, characterized in that Before sending the identification information to the second terminal device, the method further includes: A direct connection has been established with the second terminal device.

11. The method according to claim 7, characterized in that The identification information is carried in a direct connection request message sent by the first terminal device to the second terminal device.

12. The method according to claim 8 or 9, characterized in that After receiving the second message from the second terminal device, the method further includes: Save the first system information of the second terminal device.

13. A system information transmission device, characterized in that: The device is applied to a second terminal device, and includes: A communication unit, configured to communicate with the first terminal device; a processing unit, configured to receive identification information from the first terminal device before sending the second message to the first terminal device through the communication unit, wherein the identification information includes a second cell identifier, or the identification information includes the second cell identifier and a second system information value identifier; The second cell identifier is a cell identifier of a resident cell or a serving cell after the second terminal device and the first terminal device complete establishment of a direct connection, or a cell identifier of a resident cell or a serving cell of the first terminal device; The second system information value identifier is a system information value identifier of a resident cell or a serving cell of the first terminal device; and, sending a second message to the first terminal device through the communication unit according to the identification information, wherein the second message is used to request the first terminal device to send system information to the second terminal device; And, a first message from the first terminal device is received through the communication unit, and the first message includes part or all of the system information of the resident cell or the serving cell of the first terminal device.

14. The device according to claim 13, characterized in that The second message indicates first system information required by the second terminal device, and the first message includes the first system information.

15. The device according to claim 14, characterized in that The first system information is system information required by the second terminal device except the second system information, and the second system information is system information required by all terminal devices in the resident cell or service cell of the second terminal device.

16. The device according to claim 13, characterized in that The processing unit, when sending the second message to the first terminal device through the communication unit according to the identification information, is specifically configured to: If the first cell identifier and the second cell identifier are inconsistent, or the first cell identifier and the second cell identifier are consistent and the first system information value identifier is different from the second system information value identifier, system information is requested from the first terminal device through the communication unit, wherein the first cell identifier is the cell identifier of the resident cell or the service cell before the second terminal device completes the establishment of a direct connection with the first terminal device, and the first system information value identifier is the system information value identifier of the resident cell or the service cell before the second terminal device completes the establishment of a direct connection with the first terminal device.

17. The device according to claim 13, characterized in that The processing unit is further used for: Before the identification information from the first terminal device is received through the communication unit, a direct link is established with the first terminal device.

18. The device according to any one of claims 13 to 17, characterized in that: The identification information is carried in a direct connection request message sent by the first terminal device to the second terminal device.

19. A system information transmission device, characterized in that: The apparatus is applied to a first terminal device, and includes: A communication unit, configured to communicate with a second terminal device; A processing unit, configured to: Sending identification information to the second terminal device, where the identification information includes a second cell identifier, or the identification information includes a second cell identifier and a second system information value identifier; The second cell identifier is a cell identifier of a resident cell or a serving cell after the second terminal device and the first terminal device complete establishment of a direct connection, or a cell identifier of a resident cell or a serving cell of the first terminal device; The second system information value identifier is a system information value identifier of a resident cell or a serving cell of the first terminal device; receiving a second message from a second terminal device, where the second message is used to request the first terminal device to send system information to the second terminal device; A first message is sent to the second terminal device, where the first message includes part or all of the system information of the resident cell or serving cell of the first terminal device.

20. The device according to claim 19, characterized in that The second message indicates first system information required by the second terminal device, and the first message includes the first system information.

21. The device according to claim 20, characterized in that The first system information is system information required by the second terminal device except the second system information, and the second system information is system information required by all terminal devices in the resident cell or service cell of the second terminal device.

22. The device according to claim 19, characterized in that The processing unit is further used for: Before the identification information is sent to the second terminal device through the communication unit, a direct link is established with the second terminal device.

23. The device according to claim 19, characterized in that The identification information is carried in a direct connection request message sent by the first terminal device to the second terminal device.

24. The device according to claim 20 or 21, characterized in that The processing unit is further used for: After receiving the second message from the second terminal device through the communication unit, the first system information of the second terminal device is saved.

25. A system information transmission device, characterized in that: Including processor, memory and transceiver, The memory stores a computer program; The processor is used to call and execute the computer program stored in the memory, and to implement the method according to any one of claims 1 to 6 by sending and receiving data through the transceiver.

26. A system information transmission device, characterized in that: Including processor, memory and transceiver, The memory stores a computer program; The processor is used to call and execute the computer program stored in the memory, and to implement the method according to any one of claims 7 to 12 by sending and receiving data through the transceiver.

27. A terminal device, characterized in that: The method comprises a unit or a module for executing the method according to any one of claims 1 to 6.

28. A terminal device, characterized in that: The method comprises a unit or a module for executing the method according to any one of claims 7 to 12.

29. A computer program product, characterized in that When the computer program product is executed, the method according to any one of claims 1 to 6 is implemented; or, the method according to any one of claims 7 to 12 is implemented.

30. A communication system, characterized in that: It comprises the device as described in any one of claims 13 to 18 and the device as described in any one of claims 19 to 24.

31. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed, the method according to any one of claims 1 to 6 is implemented; or, the method according to any one of claims 7 to 12 is implemented.

32. A chip, characterized in that: include: A processing module and a communication interface, wherein the processing module is used to execute the method described in any one of claims 1 to 6; or, the processing module is used to execute the method described in any one of claims 7 to 12.

33. The chip according to claim 32, characterized in that: The chip also includes a storage module, which is used to store instructions, and the processing module is used to execute the instructions stored in the storage module, so that the processing module executes the method described in any one of claims 1 to 6; or, the processing module executes the method described in any one of claims 7 to 12.

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