Data transmission method for emergency communication multi-type link networking and base station equipment

Abstract

The invention provides a data transmission method for emergency communication multi-type link networking and base station equipment, a transverse link data transmission layer is additionally arranged in a communication protocol stack of the base station equipment in an emergency rescue communication network, and a transverse link directly connected between the base station equipment is constructed by means of the transverse link data transmission layer. And transmitting the transverse connection communication data needing to be interacted between the base station equipment to the opposite base station equipment through the transverse connection link. In an emergency rescue scene, the cross-linked communication data needing to be transmitted between the base station devices are directly subjected to data interaction through the cross-linked link. If the transverse connection link is interrupted, the method provided by the invention is selected, and the terminal equipment in the communication network is quickly utilized to construct an alternative link to recover the communication of the transverse connection communication data between the base station equipment. The communication networking mode under the emergency rescue network is effectively expanded, emergency rescue data transmission can be carried out through various types of link networking, and the emergency rescue efficiency and reliability can be guaranteed.

Description

Technical Field

[0001] This application relates to the field of communication technology, and in particular to a data transmission method and base station equipment for emergency communication multi-type link networking. Background Technology

[0002] In emergency rescue and disaster relief scenarios, reliable communication infrastructure is crucial for ensuring rescue efficiency. Therefore, rescue sites may contain various types of communication equipment, such as communication vehicles, drones, and site security facilities. These devices communicate with each other and ultimately connect to the rescue command center. Due to the complex environment of emergency rescue sites and the dynamic development of rescue operations, the demand for diverse emergency rescue communication networks has surged. Summary of the Invention

[0003] In view of this, embodiments of this application provide a data transmission method and base station equipment for multi-type link networking in emergency communication, so as to expand the emergency rescue communication networking methods in emergency rescue scenarios.

[0004] In a first aspect, embodiments of this application provide a data transmission method for multi-type link networking in emergency communication, wherein the method is applied to a first base station device or a second base station device, the communication protocol stack of the first base station device includes: a first crosslink data transmission layer, and the communication protocol stack of the second base station device includes: a second crosslink data transmission layer, and the method includes: A crosslink is constructed based on the first crosslink data transmission layer and the second crosslink data transmission layer; Transceive and / or receive transceiver communication data via the transceiver link.

[0005] Secondly, embodiments of this application provide a data transmission method for multi-type link networking in emergency communication, wherein the method is applied to a first base station device or a second base station device, the communication protocol stack of the first base station device includes: a first crosslink data transmission layer, the communication protocol stack of the second base station device includes: a second crosslink data transmission layer, and the method includes: If the cross link between the device and the second base station is interrupted, an alternative link is determined. The alternative link is constructed by a number of terminal devices, each of which includes: a first terminal device, a second terminal device, and a third terminal device, wherein: the first terminal device is directly connected to the first base station device, the second terminal device is directly connected to the second base station device, and the third terminal device is a terminal device that is not directly connected to the first base station device or the second base station device. The cross-connection communication data with the target base station device being the second base station device is sent to the second base station device through the alternative link, and the data returned by the second base station device is received based on the alternative link.

[0006] Thirdly, embodiments of this application provide a base station device, which is either a first base station device or a second base station device. The communication protocol stack of the first base station device includes a first crosslink data transmission layer, and the communication protocol stack of the second base station device includes a second crosslink data transmission layer. The base station device includes: The base station control module is used to construct a crosslink based on the first crosslink data transmission layer and the second crosslink data transmission layer; A cross-connect data transmission module is used to send and / or receive cross-connect communication data through the cross-connect link.

[0007] Fourthly, embodiments of this application provide a base station device, wherein the base station device is a first base station device or a second base station device, the communication protocol stack of the first base station device includes: a first crosslink data transmission layer, and the communication protocol stack of the second base station device includes: a second crosslink data transmission layer. The base station device includes: The base station control module is used to determine an alternative link if the crosslink between the base station and the second base station is interrupted. The alternative link is constructed by a number of terminal devices, each of which includes a first terminal device, a second terminal device, and a third terminal device, wherein the first terminal device is directly connected to the first base station, the second terminal device is directly connected to the second base station, and the third terminal device is a terminal device that is not directly connected to the first base station or the second base station. The cross-connect data transmission module is used to send cross-connect communication data, where the destination base station device is the second base station device, to the second base station device through the alternative link, and to receive data returned by the second base station device based on the alternative link.

[0008] Fifthly, embodiments of this application provide an electronic device, wherein the electronic device includes: a processor; and a memory storing a program; wherein the program includes instructions, which, when executed by the processor, cause the processor to perform the data transmission method for emergency communication multi-type link networking as described in the first or second aspect.

[0009] In a sixth aspect, embodiments of this application provide a non-transitory computer-readable storage medium storing computer instructions, wherein the computer instructions are used to cause a computer to execute the data transmission method for emergency communication multi-type link networking described in the first or second aspect.

[0010] The beneficial effects of this application are: This application provides a data transmission method and base station equipment for multi-type link networking in emergency communication. By adding a crosslink data transmission layer to the communication protocol stack of the base station equipment in the emergency rescue communication network, a direct crosslink is constructed between the base station equipment. Then, through this crosslink, the crosslink communication data that needs to be exchanged between the base station equipment is transmitted to the other base station equipment. Thus, in emergency rescue scenarios, the crosslink communication data that needs to be transmitted between base station equipment can be directly exchanged through this crosslink, expanding the communication network interaction methods. If the crosslink is interrupted, the method provided in this application can be used to quickly rebuild the crosslink communication data between the base station equipment by constructing an alternative link using terminal equipment in the communication network. This effectively expands the communication networking methods in emergency rescue networks, facilitates emergency rescue data transmission through multi-type link networking, and helps ensure emergency rescue efficiency and communication reliability. Attached Figure Description

[0011] Further details, features, and advantages of this application are disclosed in the following description of exemplary embodiments in conjunction with the accompanying drawings, in which: Figure 1 This paper illustrates a flowchart of a data transmission method for multi-type link networking in emergency communication provided in an embodiment of this application. Figure 2 This paper illustrates another flowchart of a data transmission method for multi-type link networking in emergency communication provided in an embodiment of this application. Figure 3 This illustration shows an application scenario of the data transmission method for multi-type link networking in emergency communication provided in an embodiment of this application; Figure 4 This invention illustrates a logical architecture diagram of the cross-connection transmission layer of a base station device provided in an embodiment of this application. Figure 5 This paper illustrates a processing flow diagram of a non-confirmation mode UCM entity provided in an embodiment of this application. Figure 6 This illustration shows a processing flow diagram of a confirmation mode CM entity provided in an embodiment of this application; Figure 7 This paper illustrates a logical structure diagram of the communication protocol stack of a base station device and a terminal device provided in an embodiment of this application. Figure 8 This illustration shows a logical structure diagram of a communication protocol stack between terminal devices provided in an embodiment of this application; Figure 9 This paper illustrates a logical architecture diagram of a base station device provided in an embodiment of this application. Figure 10 A structural block diagram of an exemplary electronic device that can be used to implement embodiments of this application is shown. Detailed Implementation

[0012] Embodiments of this application will now be described in more detail with reference to the accompanying drawings. While some embodiments of this application are shown in the drawings, it should be understood that this application can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this application. It should be understood that the drawings and embodiments of this application are for illustrative purposes only and are not intended to limit the scope of protection of this application.

[0013] It should be understood that the steps described in the method embodiments of this application may be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of this application is not limited in this respect.

[0014] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". Definitions of other terms will be given in the following description. It should be noted that the concepts of "first", "second", etc., mentioned in this application are used only to distinguish different devices, modules, or units, and are not intended to limit the order of functions performed by these devices, modules, or units or their interdependencies.

[0015] It should be noted that the terms "a" and "a plurality of" used in this application are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0016] To expand communication networking options in emergency rescue scenarios, this application provides a data transmission method and base station equipment for multi-type link networking in emergency communication. Firstly, this application provides a data transmission method for multi-type link networking in emergency communication, used to establish crosslinks between base station equipment for crosslink communication data exchange. Secondly, this application provides a data transmission method for multi-type link networking in emergency communication, used to quickly establish alternative links using terminal devices in the scenario to restore crosslink communication data exchange when a crosslink between base station equipment is interrupted. The base station equipment provided in the third aspect is used to implement the method corresponding to the first aspect, and the base station equipment provided in the fourth aspect is used to implement the method corresponding to the second aspect.

[0017] The data transmission method for multi-type link networking in emergency communication provided in this application can be applied to any base station device in an emergency communication network. For ease of distinction, the base station device executing the method provided in this application is referred to as the first base station device, and other base stations communicating with the first base station device are referred to as the second base station device. The type, size, and model of the base station device can be flexibly set according to actual needs and are not the focus of this application; therefore, this application does not impose strict limitations on them.

[0018] In this application, "multi-type links in the emergency communication network" refers to the existence of multiple types of communication links within the emergency communication network, rather than a single-link communication network. For example, due to the different types of communication links between base station devices, the emergency communication network may include direct links and indirect links. Direct links refer to links directly connecting base station devices, while indirect links refer to links indirectly connected between base station devices via other communication devices. For ease of distinction, in this embodiment, direct links between base station devices are also referred to as crosslinks. In addition to crosslinks, the emergency communication network may include multi-hop links, i.e., communication links constructed through multi-hop communication devices.

[0019] In this application, both the first base station device and the second base station device can be collectively referred to as base station devices. The communication protocol stack of the base station device includes a crosslink data transmission layer. For ease of distinction, the communication protocol stack of the first base station device includes a first crosslink data transmission layer, and the communication protocol stack of the second base station device includes a second crosslink data transmission layer. In some possible embodiments, it can be as follows... Figure 1 As shown, the method includes the following steps: S101. Based on the first crosslink data transmission layer and the second crosslink data transmission layer, construct a crosslink between the first base station device and the second base station device; S102, Send and / or receive cross-link communication data through the cross-link.

[0020] In this application, cross-connect communication data refers to data in which both the sending source device and the receiving destination device are base station devices. This data is normal communication interaction data. In emergency rescue scenarios, the cross-connect communication data can be a data packet for communication interaction between a first base station device and a second base station device. This data packet carries the interaction content generated during the emergency rescue process.

[0021] Thus, by adding a crosslink data transmission layer to the communication protocol stack of base station equipment in the emergency rescue communication network, a direct crosslink is established between base station equipment. Then, through this crosslink, the crosslink communication data that needs to be exchanged between base station equipment is transmitted to the other base station equipment. In this way, in emergency rescue scenarios, crosslink communication data that needs to be transmitted between base station equipment can be directly exchanged through this crosslink, expanding the communication network's interaction methods.

[0022] In this application, the basic unit of transmission processing at each layer of the communication protocol stack can be simply referred to as a PDU (Protocol Data Unit). The PDUs corresponding to each layer are not the same. For example, the PDU transmitted at the physical layer is a bit, the PDU transmitted at the data link layer is a data frame, including a data frame header, payload, and data frame trailer, and the PDU transmitted at the network layer is a data packet or data packet, including an IP header. In this embodiment, the basic unit of transmission at each layer of the communication protocol stack of the base station equipment and the terminal equipment will be collectively referred to as a PDU, without any specific differentiation.

[0023] In some possible embodiments, the data transmission method for multi-type link networking in emergency communication provided in this application can be as follows: Figure 2 As shown, the method includes the following steps S21 and S22: S21. If the cross link between the device and the second base station is interrupted, determine the alternative link.

[0024] One possible implementation method is as follows: Figure 3 As shown, this alternative link (the link corresponding to the dashed line in the figure) is constructed by several terminal devices, each of which includes: a first terminal device, a second terminal device, and a third terminal device. The first terminal device is directly connected to the first base station device, the second terminal device is directly connected to the second base station device, and the third terminal device is a terminal device not directly connected to either the first or second base station device. In other words, the first terminal device is directly connected to the first base station device, the second terminal device is directly connected to the second base station device, and the third terminal device is a terminal device indirectly connected to the first and second base station devices through the first and second terminal devices.

[0025] In the embodiments of this application, the terms "first terminal device", "second terminal device" and "third terminal device" are collective terms and do not refer to a specific terminal device. That is, in the embodiments of this application, the number of first terminal devices can be several, the number of second terminal devices can be several, and the number of third terminal devices can be several.

[0026] S22. The cross-connection communication data with the destination base station device being the second base station device is sent to the second base station device through the alternative link, and the data returned by the second base station device is received based on the alternative link.

[0027] The core of this application's embodiments is the cross-link between base station devices (such as...). Figure 3 When a crosslink (solid line link) is interrupted, a usable alternative link is quickly constructed using terminal devices in the environment that have direct or indirect connections to the base station equipment. This alternative link replaces the crosslink to restore communication between the base station equipment, ensuring the reliability of the emergency communication network. Specifically, after a crosslink between base station equipment is interrupted for various reasons, the first terminal device with an access link to the first base station equipment, the second terminal device with an access link to the second base station equipment, and the third terminal device acting as a relay are quickly identified. An alternative link is constructed, and then the communication link between the first and second base station equipment is switched from the crosslink to this alternative link, allowing normal data interaction between the two to resume.

[0028] Since the methods provided in the first aspect and the second aspect have the same application scenarios, the following will provide a detailed explanation of each step of the method provided in this application, using specific examples: In the embodiments of this application, the first base station device and the second base station device can be collectively referred to as base station devices. In the application stage of the method provided in this application, the base station control module or unit inside the base station device mainly executes the above steps S101, S102, S21 and S22 to control the communication logic of the entire base station device.

[0029] In this embodiment, to enable direct communication connections between base station devices and construct crosslink communication links, the communication protocol stack of the base station devices is improved by adding a crosslink data transmission layer. Specifically, in this embodiment, the communication protocol stack of the base station devices includes a crosslink data transmission layer. This crosslink data transmission layer can monitor the link status of the crosslink and determine whether the crosslink has been interrupted based on the detection results. The internal execution logic of the crosslink data transmission layer includes link status monitoring logic and link termination determination logic.

[0030] In some possible embodiments, the crosslink data transmission layer provided in this application includes: an unacknowledged mode entity and an acknowledged mode entity. During the execution of the above-described steps S102 and S22, the crosslink communication data can be sent and / or received through the unacknowledged mode entity, or the crosslink communication data can be sent and / or received through the acknowledged mode entity. It can be understood that the crosslink data transmission layer provided in this application has an acknowledged mode entity for data interaction using an acknowledged mode, and an unacknowledged mode entity for data interaction using an unacknowledged mode. The acknowledged mode entity executes the acknowledged mode interaction logic, and the unacknowledged mode entity executes the unacknowledged mode interaction logic.

[0031] In this embodiment, the unconfirmed mode entity is referred to as an Un-Confirm Mode entity, or simply a UCM entity, hereinafter collectively referred to as the UCM entity. The UCM entity determines the operating mode of the base station equipment. The UCM entity is suitable for communication services with high real-time requirements but low sensitivity to packet loss rates, and it possesses the capability to send and receive communication data. As one implementation, the unconfirmed mode entity may include an unconfirmed mode sending entity (referred to as a UCM sending sub-entity) and an unconfirmed mode receiving entity (referred to as a UCM receiving sub-entity). Therefore, when sending and / or receiving cross-connection communication data through the unconfirmed mode entity, the cross-connection communication data can be sent through the UCM sending sub-entity and received through the UCM receiving sub-entity.

[0032] In this embodiment, the English name for the Confirmed Mode entity is "Confirmed Mode entity," which can also be abbreviated as CM entity. The CM entity determines the operating mode of the base station equipment. It is the logical entity that implements the confirmed mode transmission function of the entire base station equipment. Through the Automatic Repeat Request (ARQ) mechanism, it ensures the reliability of data transmission and is suitable for non-real-time communication services with low fault tolerance and high latency tolerance. Similarly, the CM entity also has the capability to send and receive communication data. Therefore, when sending and / or receiving crosslink communication data through the crosslink data transmission layer, two entities can be used for sending and receiving crosslink communication data. Similar to the UCM entity, in this application, the Confirmed Mode entity (CM entity) includes: a confirmed mode sending entity (which can be abbreviated as CM sending sub-entity) and a confirmed mode receiving entity (which can be abbreviated as CM receiving sub-entity). Crosslink communication data is sent through the CM sending sub-entity and received through the CM receiving sub-entity.

[0033] In some possible embodiments, whether to use a UCM entity or a CM entity for data interaction can be determined through the following steps: If the cross-connection communication data corresponds to the first-level packet loss rate constraint, then the cross-connection communication data is sent and / or received through the confirmation mode entity; If the cross-connection communication data corresponds to the second-level packet loss rate constraint, then the cross-connection communication data is sent and / or received through the unacknowledged mode entity. Wherein, the first packet loss rate constrained by the first-level packet loss rate constraint is less than the second packet loss rate constrained by the second-level packet loss rate constraint.

[0034] In one implementation method, whether the crosslink communication data specifically corresponds to the first-level packet loss rate constraint or the second-level packet loss rate constraint can be determined based on the packet loss rate field carried in the header of the data packet generated by the crosslink data transmission layer. This packet loss rate field can be compared with a set packet loss rate threshold. If it is greater than the threshold, the crosslink communication data is considered to correspond to the second-level packet loss rate constraint; if it is less than or equal to the threshold, it is considered to correspond to the first-level packet loss rate constraint. The packet loss rate threshold can be flexibly set according to actual application requirements, and this application does not impose strict limitations on it.

[0035] As described above, the UCM entity is suitable for communication services with high real-time requirements but low sensitivity to packet loss rate, while the CM entity is suitable for non-real-time communication services with low fault tolerance and high latency tolerance. Therefore, when base station equipment performs cross-connection communication data transmission and reception, it needs to consider the actual communication service scenario and select the appropriate entity based on the packet loss rate requirements of the cross-connection communication data. If the packet loss rate requirement for the cross-connection communication data is high, and the packet loss rate needs to be controlled below a certain threshold, the automatic retransmission mechanism of the CM entity should be selected to ensure reliable data transmission. Conversely, if the packet loss rate of the cross-connection communication data is not high, but real-time requirements are high, the UCM entity should be selected for data transmission to ensure real-time data transmission.

[0036] In some possible embodiments, the relationship between the crosslink data transmission layer of the first base station device and the crosslink data transmission layer of the second base station device can be as follows: Figure 4 As shown, data transmitted by the UCM transmitting sub-entity of the first base station device is received by the UCM receiving sub-entity of the second base station device, and the UCM receiving sub-entity of the first base station device receives data transmitted by the UCM transmitting sub-entity of the second base station device. Similarly, data transmitted by the AM transmitting sub-entity of the first base station device is received by the AM receiving sub-entity of the second base station device, and the AM receiving sub-entity of the first base station device receives data transmitted by the AM transmitting sub-entity of the second base station device.

[0037] As one implementation method, it can be as follows Figure 5As shown, when the crosslink data transmission layer between the first base station device and the second base station device exchanges information through the UCM sending sub-entity and the UCM receiving sub-entity, the sending sub-entity only needs to send the data packets to the receiving sub-entity in the order of the data packets; the receiving end does not need to send back a reception acknowledgment message after receiving the data packets. For example, the UCM sending sub-entity in the first base station device sends data to the UCM receiving sub-entity of the second base station device in the order of UCM1...UCMn corresponding to the data packets.

[0038] Among them, such as Figure 5 As shown, when transmitting data, the UCM transmitting sub-entity is only responsible for adding the corresponding data packet header to the Protocol Data Unit (PDU) submitted by the upper-layer entity and then submitting it to the lower-layer entity for transmission. When receiving data, the UCM receiving sub-entity is only responsible for removing the data packet from the Protocol Data Unit (PDU) submitted by the lower-layer entity and then submitting it to the upper-layer entity.

[0039] In this application embodiment, the crosslink data transmission entity includes: a UCM sending sub-entity, wherein, in some possible embodiments, sending the crosslink communication data through the unacknowledged mode sending entity includes: The non-confirmed mode sending entity adds a non-mode data packet header to the cross-connection communication data to obtain a second data packet to be sent; The second data packet to be sent is sent to the unacknowledged receiving entity of the second base station device.

[0040] In other words, if the cross-connect communication data is transmitted in unacknowledged mode in this application, a packet header can be added to the cross-connect communication data by the UCM sending sub-entity. The packet header added by the UCM sending sub-entity includes: source address information, destination address information, and packet sequence number. The source address information and destination address information can be any information that can characterize the device's location in the communication network, such as IP address, MAC address, industry-specific address, etc. As an example, the PDU format of the Protocol Data Unit (PDU) processed by the UCM sending sub-entity and the UCM receiving sub-entity can be as shown in Table 1 below, including PDU SN (PDU sequence number), source address information, destination address information, and cross-connect communication data content (Data). Table 1. Schematic diagram of UCM data packet (UCM PDU) format corresponding to cross-connection communication data.

[0041] In Table 1 and Tables 2 through 6 below, Oct1...Octn is an abbreviation for Octet, specifically an 8-bit group, i.e., one byte, representing different bytes. For example, in Table 1, Oct1 carries the information of the first byte: PDU number, and so on for the others.

[0042] In this embodiment, for crosslink communication data, the data transmission rate is higher when using a crosslink than when using an alternative link. Therefore, the sequence number range of data packets for crosslink communication can be larger than that for alternative link communication. As a preferred embodiment, the maximum value of the sequence number range can be 2048 or 4096. Furthermore, to ensure seamless switching to the alternative link when the crosslink is interrupted, the sequence number range of data packets for the crosslink can be consistent with that of the alternative link.

[0043] As one implementation method, during the process of determining whether the crosslink has been interrupted in step S21, if the base station equipment uses the UCM entity to send and receive data through the crosslink, the UCM receiving entity can analyze the received data packets. If the sequence number of the received data packets is out of order, or the degree of out-of-order exceeds the set out-of-order threshold, such as m data packets being lost consecutively, the UCM receiving entity can determine that the crosslink between the base station equipment and the second base station equipment has been interrupted. At this time, the interruption of the crosslink is uploaded to the base station equipment control module in the base station equipment, and the base station equipment control module executes step S21 to determine the corresponding alternative link.

[0044] In this embodiment, data transmitted by the CM transmitting sub-entity of the first base station device is received by the CM receiving sub-entity of the second base station device, and the CM receiving sub-entity of the first base station device receives data transmitted by the CM transmitting sub-entity of the second base station device. For example, it can be as follows... Figure 6 As shown, during data transmission, the CM transmitting sub-entity not only needs to send data packets in sequence, but also needs to wait for the receiving end to send a response message after receiving a certain number of data packets. If the response message sent by the receiving end contains the sequence number of the correctly received data packet and the sequence number of the incorrectly received data packet, then the incorrectly received data packet needs to be retransmitted. Therefore, the CM entity in the cross-connected transport layer of the base station equipment is divided into two functions: transmitting and receiving. These two functions are interconnected, unlike the UCM entity where the transmitting and receiving sub-entities are completely separate and unrelated.

[0045] In this embodiment, the base station device has at least one CM entity, and also includes at least one UCM transmitting sub-entity and one UCM receiving sub-entity. In actual products, there may be multiple CM entities. For example, when the first base station device and the second base station device include crosslinks, and a crosslink also exists between the first base station device and the fourth base station device, at least two CM entities interact with the second base station device and the fourth base station device respectively through the crosslinks for crosslink communication data exchange. Each CM entity corresponds to one crosslink. When the performance requirements of crosslink communication data differ significantly, corresponding CM transmitting sub-entities and CM receiving sub-entities can be set up separately for different communication services. For example, for service A with high real-time requirements and service B with low real-time requirements, a pair of CM transmitting sub-entities and CM receiving sub-entities can be set up respectively. For example, the first CM transmitting sub-entity and the first CM receiving sub-entity are one pair, and the second CM transmitting sub-entity and the second CM receiving sub-entity are another pair. Similarly, the number of UCM entities can be flexibly set according to actual connection requirements, and this application does not impose a strict limitation.

[0046] In some possible embodiments, the above-described transmission of cross-connect communication data via the CM entity includes: The acknowledgment mode sending entity adds an acknowledgment mode data packet header to the cross-connection communication data to obtain a first data packet to be sent. Send the first data packet to be sent to the second base station device, start the first timer and listen for the cross-connection communication data reception response message sent by the second base station device; If the first timer terminates and no response message for receiving the cross-connection communication data is received, then the first data packet to be sent is resent to the second base station device; If the first timer receives a cross-connection communication data reception response message during its operation, the duration of the first timer is reset to its initial value.

[0047] One possible implementation method is as follows: Figure 6 As shown, the CM entity mainly takes the data unit SDU submitted by the upper-layer entity, adds a packet header to it to form a PDU with a packet sequence number, and then submits it to the lower-layer entity for transmission. During this process, the sequence number of the PDU is recorded. The contents of the SDU and PDU are kept in the buffer until a reception acknowledgment message is received from the receiver confirming correct reception. If a reception acknowledgment message is received from the receiver confirming correct reception, the SDU and PDU with the corresponding sequence number are cleared from the buffer.

[0048] During the process, the waiting time for the retransmission mechanism can be limited by setting a first timer T1000. If a receive acknowledgment message for cross-connection communication data is received during the operation of the first timer T1000, the system can wait for a new first timer T1000 operation period to receive the acknowledgment message again. If no receive acknowledgment message for the cross-connection communication data is received before the first timer terminates, the corresponding data packet can be retransmitted to the second terminal device.

[0049] Based on this, in some possible embodiments, the above-mentioned reception of cross-connection communication data via the CM receiving sub-entity can be achieved through the following steps: If the acknowledgment mode receiving entity receives a data packet sent by the lower-level entity, it starts a second timer; If all data packets of cross-connection communication data are received during the operation of the second timer, then the second timer is restarted.

[0050] During the process, the waiting time for the CM receiving sub-entity to receive cross-connect communication data packets can be limited by setting a second timer T1001. Within this waiting time of the second timer T1001, it can be determined whether all data packets of the cross-connect communication data have been received based on the sequence number carried in the header of the received data packets. If all data packets of the cross-connect communication data have been received, the second timer is restarted to start a new round of cross-connect communication data reception.

[0051] In this embodiment of the application, as one implementation method, when the CM transmitting sub-entity of the sending source base station equipment sends data to the CM receiving sub-entity of the receiving destination base station equipment via a crosslink, the format of the PDU used can be as shown in Table 2 below, including: PDU SN (PDU sequence number), sending source address information, receiving destination address information, crosslink communication data content (Data), D / C (Data / Control), and R (redundant bits). Among them, D / C is used to identify whether the bit belongs to data or control signaling. The R bit is used to indicate newly added functions to facilitate subsequent protocol expansion.

[0052] Table 2. Schematic diagram of CM Data Packet (CM Data PDU) format corresponding to cross-connection communication data.

[0053] In this embodiment, after receiving the PDU sent by the sending sub-entity of the CM of the receiving destination base station device, the CM needs to send a reception response message to the receiving sub-entity of the CM of the sending source base station device, or send a control message to the base station control module according to the reception situation. At this time, the PDU format of the response message or control message generated by the CM entity of the receiving destination base station device can be as shown in Table 3 below: Table 3. Schematic diagram of CM Control Message Data Packet (CM Control PDU) format corresponding to cross-connection communication data.

[0054] In this context, the sending source base station equipment and the receiving destination base station equipment are corresponding concepts. The sending source base station equipment refers to the base station equipment that transmits cross-connected communication data, and the receiving destination base station equipment refers to the base station equipment that receives cross-connected communication data. For example, when the first base station equipment sends cross-connected communication data to the second base station equipment, the first base station equipment is the sending source base station equipment, and the second base station equipment is the receiving destination base station equipment.

[0055] As one implementation method, the process of determining whether the cross-link has been interrupted in step S21 above can be achieved in the following way: If the CM entity continuously sends N data packets and does not receive a response message from the second base station device after sending all N data packets, it can be determined that the crosslink between the CM entity and the second base station device has been interrupted.

[0056] The number of data packets N depends on the rate of the crosslink; the higher the rate of the crosslink, the larger the value of N, and the two are positively correlated. In one implementation, the CM entity can upload information about the crosslink interruption to the base station control module within the base station equipment, which then executes step S21 to determine the corresponding alternative link. Alternatively, in another implementation, the CM entity can wait for a period of time; if it receives a reception response message from the second base station equipment during this waiting period, it can continue transmitting.

[0057] In the embodiments of this application, it can be as follows Figure 6As shown, after receiving a data packet from the CM sending sub-entity of the first base station device, the CM receiving sub-entity in the second base station device can generate an acknowledgment data packet as a reception response message, and then send this reception response message back to the first base station device through the CM sending sub-entity in the second base station device. The header of the acknowledgment data packet carries an acknowledgment field, which indicates one or more of the following: the sequence number of the first packet of a correctly received data packet, the sequence number of the second packet of an incorrectly received data packet, or the sequence number of the third packet of a data packet that was not received. Then, the CM receiving sub-entity of the first base station device can determine whether the second base station device has correctly received the data packet by using the acknowledgment field in the header of the received reception response message. If the data packet was not correctly received, it will be retransmitted.

[0058] As another possible implementation, when performing step S21 above, the base station control module in the first base station device can control the signal transmission module of the first base station device to send a crosslink detection signal to the second base station device through the crosslink between the first base station device and the second base station device. Within a set monitoring period, it can determine whether the crosslink has been interrupted based on whether a crosslink detection result signal based on the crosslink detection signal is received from the second base station device. If no crosslink detection result is received within the monitoring period, it indicates that the crosslink has been interrupted; if the crosslink detection result is received within the monitoring period, it indicates that the crosslink has not been interrupted.

[0059] Based on this, in some possible embodiments, when performing step S21, it can be determined whether the cross link has been interrupted by the following steps: S21-1. Using the crosslink data transmission layer, send several crosslink communication data packets to the second base station device based on the crosslink, and receive the receive response message returned by the crosslink data transmission layer of the second base station device. S21-2. If the cross-link communication data packet is sent and no confirmation message is received, it is determined that the cross-link has been interrupted.

[0060] In step S21-1, the first base station uses its own crosslink data transmission layer to send several (let's say N) crosslink communication data packets to the crosslink data transmission layer of the second base station device. The first base station device can determine whether the crosslink is abnormal by listening for the presence of a receive acknowledgment message returned by the second base station device. If the crosslink is normal, the second base station will return a receive acknowledgment message to the first base station device after receiving each crosslink communication data packet, indicating that it has received the crosslink communication data packets sent by the first base station device. If the first base station device has not yet received a receive acknowledgment message returned by the crosslink data transmission layer of the second base station device from the crosslink, it indicates that the crosslink is abnormal, possibly due to weak signal or no signal at all.

[0061] As one implementation method, a confirmation message waiting period can be set (controlled by a timer). If a receive response message from the second base station is received within the confirmation message waiting period, it indicates that the crosslink only has a weak signal and has not been interrupted. However, if no receive response message from the second base station is found in the crosslink after the confirmation message waiting period has expired, it indicates that the crosslink between the two has been interrupted.

[0062] In one implementation, step S21-2 can be performed by the crosslink data transmission layer itself to quickly determine whether the crosslink has been interrupted based on the data packet sending status and the specific details of the received acknowledgment messages. For example, if the crosslink data transmission layer finds that all N data packets that need to be sent have been sent, but no acknowledgment messages corresponding to a data packet have been received, it can quickly determine that the crosslink has been interrupted.

[0063] By using the embodiments of this application, the specific communication status of the crosslink can be determined by the data packets sent and the acknowledgment messages of the crosslink interconnected by the crosslink data transmission layer provided in this application. This facilitates the rapid determination of the crosslink communication quality between base station devices, so that when a crosslink interruption occurs, the normal communication between base station devices can be maintained immediately through the methods provided in the embodiments of this application.

[0064] In this embodiment, when the base station control module receives a report from the UCM entity or CM entity that a crosslink has been interrupted, it determines that a crosslink has been interrupted. At this time, it can control the CM transmitting sub-entities and UCM transmitting sub-entities to perform link switching. Each transmitting sub-entity can suspend data transmission and execute the data transmission method provided in the second aspect of this application to perform a seamless switch from the crosslink to an alternative link. The specific seamless switching process is as follows: Specifically, the base station control module of the first base station equipment can identify the terminal equipment accessing it as the first terminal equipment, and then transfer the crosslink communication data originally sent on the crosslink to the alternative link for transmission. The transferred crosslink communication data includes: 1) data packets that have been sent but have not yet received an ACK message from the second base station equipment confirming correct reception; and 2) new crosslink communication data packets that have never been sent. By transferring these two types of data packets (1) and 2) to the alternative link, the alternative link takes over the transmission and reception of crosslink communication data from the crosslink link.

[0065] The alternative link is a communication link constructed using terminal devices that are directly or indirectly connected to the first base station equipment and the second base station equipment. As one implementation method, the link structure of this alternative link is as follows: First base station equipment <—> First terminal equipment <—> Third terminal equipment <—> Second terminal equipment <—> Second base station equipment The number of third-terminal devices is unlimited. The entire alternative link may include several third-terminal devices or may not include any third-terminal devices. For example, a simple alternative link can be built directly through the first terminal device and the second terminal device.

[0066] In this embodiment, a Uu connection is established between the terminal device and the base station device via a Uu structure, and a direct connection is established between the terminal devices via a terminal direct link interface. Based on this, the first terminal device and the first base station device establish a first Uu connection via a Uu interface, the second terminal device and the second base station device establish a second Uu connection via a Uu interface, and all the terminal devices establish a direct connection via a terminal direct link interface.

[0067] To ensure the correct construction of a usable alternative link, improvements are needed to the communication protocol stacks of both the base station equipment and the terminal equipment. Therefore, in some possible embodiments, the base station equipment's communication protocol stack, in addition to the aforementioned crosslink data transmission layer, may also include a base station crosslink service adaptation layer (HDAP layer), which may be as follows: Figure 7 As shown, the relative relationship between the crosslink data transmission layer and the base station crosslink service adaptation layer is as follows: the crosslink data transmission layer is located above the base station crosslink service adaptation layer.

[0068] Similarly, Figure 7As shown, the communication protocol stack of each terminal device includes: a terminal crosslink service adaptation layer (HDAP layer) and a direct link data application layer (ZTAP layer). Specifically, the communication protocol stack of the terminal device directly connected to the base station device includes, in addition to the direct link data application layer, the terminal crosslink service adaptation layer. That is, in this application, the communication protocol stack of the first terminal device and the second terminal device also includes the terminal crosslink service adaptation layer. The third terminal device may not include the terminal crosslink service adaptation layer, wherein the base station crosslink service adaptation layer communicates with the terminal crosslink service adaptation layer and the direct link data application layer communicates with each other.

[0069] As one implementation method, the communication protocol stack of the base station device can be specifically as follows: Figure 7 As shown, in addition to the aforementioned crosslink data transmission layer and base station crosslink service adaptation layer, the communication protocol stack of the base station equipment may also include: physical layer (i.e., PHY in the diagram), radio link control layer (i.e., RLC layer in the diagram) / media access control layer (i.e., MAC layer in the diagram), and security encryption layer (i.e., packet data aggregation protocol layer PDCP in the diagram). The layers, from bottom to top, are: physical layer (i.e., PHY in the diagram), radio link control layer (i.e., RLC layer in the diagram) / media access control layer (i.e., MAC layer in the diagram), security encryption layer (i.e., packet data aggregation protocol layer PDCP in the diagram), base station crosslink service adaptation layer (i.e., HSAP in the diagram), and crosslink data transmission layer.

[0070] In this embodiment of the application, the communication protocol stack of the terminal device can be as follows: Figure 8 As shown, from bottom to top, the layers include: Physical Layer (PHY), Radio Link Control Layer (RLC) / Media Access Control Layer (MAC), Security Encryption Layer (PDCP), Terminal Crosslinking Service Adaptation Layer (HDAP), and Direct Link Data Application Layer (ZTAP). The Terminal Crosslinking Service Adaptation Layer and the Direct Link Data Application Layer (ZTAP) are located on the same layer. The layers are numbered from bottom to top as follows: Layer 1 (L1), Layer 2 (L2), Layer 3 (L3), ..., Layer N (LN).

[0071] In the embodiments of this application, it can be as follows Figure 8 As shown, there is a one-to-one correspondence between the communication protocol stacks of the base station equipment and the terminal equipment. They operate at the same layer of the communication protocol stack and interact via a Uu connection. Here, a Uu connection refers to a communication link established through the device's Uu interface. For example, as... Figure 8As shown, the base station crosslink service adaptation layer HDAP of the base station equipment and the terminal crosslink service adaptation layer HDAP of the terminal equipment are both at layer 4 in their respective communication protocol stacks. They are on the same layer and interact with each other through the Uu connection created by the Uu interface.

[0072] Based on this, in this embodiment of the application, the base station crosslinking service adaptation layer (HDAP) of the first base station device and the terminal crosslinking service adaptation layer (HDAP) of the first terminal device interact via a Uu connection. Similarly, the base station crosslinking service adaptation layer (HDAP) of the second base station device and the terminal crosslinking service adaptation layer (HDAP) of the second terminal device interact via a Uu connection. Similarly, the communication protocol stacks of terminal devices also have a one-to-one correspondence. Devices at the same layer of the communication protocol stack are connected through Zt, where Zt connection refers to a pass-through connection, specifically a communication link created through a pass-through interface.

[0073] For example, such as Figure 8 As shown, the pass-through data application layer (ZTAP) of both the first and second terminal devices is located at Layer 4 of their respective communication protocol stacks, meaning they are on the same layer. The ZTAPs of the first and second terminal devices interact via a Zt connection created through the Zt interface. Therefore, in this embodiment, the terminal devices interact via a Zt connection created through the Zt interface based on their respective pass-through data application layers (ZTAPs).

[0074] As described above, if it is determined that the crosslink between the device and the second base station is interrupted, a link switchover can be initiated. In some possible embodiments, the base station control module can send a "crosslink pass-through mode termination information" to the crosslink data transmission layer to terminate the transmission of crosslink communication data through the crosslink. Specifically, this may include the following steps: If the crosslink is interrupted, stop sending data packets to the crosslink; The first data packet arriving at the crosslink data transmission layer is cached in the service data cache area, and the second data packet is cached in the initial transmission data cache area. The second data packet is the data packet after the crosslink data transmission layer adds a data packet header to the first data packet.

[0075] During the process, if the aforementioned second data packet is a data packet with a header added to the acknowledgment mode entity (i.e., CM entity) in the crosslink data transmission layer, the method may further include the following steps: The third data packet is buffered in the retransmission buffer. The third data packet is the second data packet that has been sent but has not yet received a return reception response message from the second base station device.

[0076] As one implementation method, when the crosslink data transmission layer between the UCM entity and the CM entity and the second base station device is interrupted, the following specific behaviors can be performed: 1) Stop data transmission, including the sending entity stopping the transmission action, which may include: the UCM sending sub-entity and the CM sending sub-entity stopping the transmission of data packets. Specifically, it may include: UCM stops adding headers to child entities and stops sending PDUs with added headers to lower-level entities.

[0077] The CM transmitting sub-entity stops adding packet headers and simultaneously stops sending PDUs with added headers to lower-level entities. Since the CM entity is waiting for the receiver to send back a reception response message, the first timer (i.e., timer T1000) running within the CM entity limits the duration of waiting for the receiver to send back a reception response message. The CM transmitting sub-entity can stop the first timer T1000 after receiving the crosslink pass-through mode termination information sent by the base station control module.

[0078] 2) Data caching, which includes caching data submitted from upper and lower level entities to a specified path, and may include: UCM entity actions and CM entity actions, wherein: UCM entity actions include: For PDUs that have been received but for which headers have not yet been added, the UCM sending sub-entity treats them as received service data SDUs and can cache the service data SDU cache. For PDUs that have been received and for which headers have been added, the PDUs with added headers can be cached in the initial transmission data cache.

[0079] When the crosslink of the UCM receiving sub-entity is interrupted, it can continue to receive PDUs submitted by the lower layer, then remove the packet header of the PDU to obtain the service data SDU, and then cache the SDU in the service SDU cache area. At the same time, it can also directly cache the received PDUs in the received PDU cache area.

[0080] In this embodiment, the data cached in the service data SDU buffer is typically delivered to the upper-layer service data entity according to the SDU sequence number (i.e., SDUSN). When the crosslink pass-through mode termination notification message is received from the base station control module, the UCM receiving sub-entity continues to receive PDUs delivered from the lower layer only if the lower layer still has correctly received data to deliver. If the lower layer has no correctly received data to deliver, the UCM receiving sub-entity only records the sequence number (i.e., PDU SN) of the PDU that has been correctly received and notifies the base station control module of the recorded PDU SN so that the base station control module can send the PDU SN to the sending end's UCM sending sub-entity when the alternative link becomes effective.

[0081] CM entity actions include: The CM sends a sub-entity, buffers the PDU with added headers in the initial transmission buffer, and simultaneously notifies the upper-layer service layer entity to suspend sending data packets to it. Data packets that have already reached the crosslink data transmission layer from the service layer are first buffered in the service data SDU buffer. Furthermore, for the CM entity's retransmission mechanism, the crosslink data transmission layer also includes a retransmission buffer. This retransmission buffer is used to buffer PDUs with added headers that have been sent but have not yet received a return acknowledgment message from the second base station device; that is, it buffers PDUs that have been sent but have not yet received an ACK from the receiving base station.

[0082] The CM receiving sub-entity will continue to receive PDUs submitted by the lower layer, remove the packet header from the PDUs to obtain the service data SDU, and then place the service data SDU into the service data SDU buffer. The service data SDU buffer then delivers the SDU to the upper-layer service data entity according to the SDU sequence number (i.e., SDU SN), and stops the second timer T1001. The buffer of the CM receiving sub-entity is similar to that of the UCM receiving sub-entity, both including: a received PDU buffer and a service data SDU buffer.

[0083] 3) Seamless handover, including packet loss retransmission and new packet continuation. After the CM and UCM entities stop sending data and complete the corresponding data buffering, the crosslink data transmission layer can resume transmission of crosslink communication data via an alternative link. It is important to note that this crosslink communication data refers to communication data where both the source transmitting device and the destination receiving device are base station devices, and does not solely refer to communication data transmitted via the crosslink.

[0084] The base station control module can determine whether a seamless handover process can be initiated based on the availability of alternative links. If the base station equipment finds an available alternative link, it will generate a corresponding route ID based on the alternative link and identify the identified alternative link through the route ID. Then, the confirmed route ID will be sent to the crosslink data transmission layer. At the same time, the base station control module can send the sequence number (PDU SN) of the data packets currently received by the second base station to the UCM entity and CM entity, so that the UCM entity and CM entity in the crosslink data transmission layer can continue to retransmit lost packets and resume new packets based on the alternative link.

[0085] The process by which the UCM entity continues to retransmit lost packets and resume transmission of new packets based on the alternative link can be described as follows: The UCM transmitting sub-entity can retrieve the PDU with sequence number SN+1 from the initial transmission data buffer based on the received PDU SN. Then, starting with the PDU with sequence number SN+1, it delivers all PDUs in the initial transmission data buffer, from SN+1 onwards, to the lower-level entity and then transmits them to the second base station device via the alternative link. If the UCM transmitting sub-entity does not receive the PDU SN from the base station control module, it can directly deliver the PDUs in the initial transmission data buffer to the lower-level entity in PDU SN sequence order and then transmit them to the second base station device via the alternative link. Using this implementation, the UCM transmitting sub-entity maintains the initial transmission data buffer and changes the PDU SN based on the PDU SN currently received by the receiving end. This makes the entire unacknowledged mode transmission smoother, reduces out-of-order data packets, and helps ensure the reliability of UCM mode communication.

[0086] For the UCM receiving sub-entity, if the sequence number (PDU SN) of the currently received PDU was sent to the UCM sending sub-entity of the second base station device when the link handover was completed, then data packets following that SN can continue to be received based on that PDU SN. If no PDU with sequence number SN+1 is received, packet loss is confirmed, and a packet loss report can be generated and reported to the base station control module. Then, PDU reception of data packets continues. If the PDU SN was not sent to the UCM sending sub-entity of the second base station device when the link handover was completed, then the PDU sent by the UCM sending sub-entity of the second base station device is directly received, and the corresponding PDU SN sequence number is obtained from that PDU. If multiple PDUs are received and the SN sequence numbers are not consecutive, a packet loss report can be reported to the base station control module to inform the base station control module that packet loss has occurred.

[0087] The process by which the CM entity continues to retransmit lost packets and resume transmission of new packets based on the alternative link can be described as follows: The CM sending sub-entity restarts the first timer T1000, and then sends the buffered data to the second base station device via the alternative link. The CM receiving sub-entity can first generate a cross-connected CM ControlPDU based on the PDU format shown in Table 3 above, then include the SN of the received PDU and the SN of the incorrectly received PDU, and generate a receive acknowledgment message to send to the peer base station device. If packet loss occurs, the second base station device can send the SN of the currently correctly received data packet back to the first base station device via the receive acknowledgment message, and then the first base station device will retransmit the data packet starting from SN+1.

[0088] Specifically, in some embodiments, based on the relevant communication interaction logic of the UCM entity and CM entity described above, the process of sending the cross-connection communication data of the target base station device as the second base station device to the second base station device through the alternative link in step S22 may include the following steps S22-1 and S22-2: S22-1. The cross-link communication data recorded by the cross-link data transmission layer is accessed to the base station cross-link service adaptation layer through inter-layer primitive notification. S22-2, The cross-connection communication data is sent by the base station cross-connection service adaptation layer to the terminal cross-connection service adaptation layer of the first terminal device, and then forwarded to the terminal cross-connection service adaptation layer of the second terminal device via the direct link data application layer of each terminal device, so that the terminal cross-connection service adaptation layer of the second terminal device forwards the cross-connection communication data to the base station cross-connection service adaptation layer of the second base station device.

[0089] The crosslink communication data recorded by the crosslink data transmission layer includes the data cached in the first, second, and third buffers mentioned above. For example... Figure 8 As shown, the communication protocol stack includes several layers, and upper and lower layers can interact through inter-layer primitives. In this embodiment, inter-layer primitives refer to a mechanism used by the layers in the communication protocol stack to exchange information and control operations. These inter-layer primitives can be used to implement service requests, status reports, and event reports between layers. The types of inter-layer primitives include: Request, Indication, Response, and Confirm.

[0090] As one implementation method, step S22-1 described above can be achieved through the following steps: Determine the sequence number of the cross-connection communication data currently received by the second base station device, and determine the protocol data unit to be sent of the cross-connection communication data based on the sequence number; The protocol data unit to be sent is transmitted to the base station data service adaptation protocol layer through the inter-layer primitive notification.

[0091] Specifically, the crosslink data transmission layer can use this inter-layer primitive to notify the data cached in the first, second, and third buffers to the next layer's service data adaptation protocol layer (HDAP), so as to transfer the record data cached by the CM entity and UCM entity to the HDAP on the access side through the inter-layer primitive.

[0092] In one implementation method, step S22-1 can be performed through the following steps: The Base Station Service Adaptation Protocol (LSAP) layer packages the cross-connection communication data into a Base Station Service Adaptation Protocol (LSAP) data packet. The data format of the base station service adaptation protocol data packet includes: route identifier information RouteID and service type identifier USID. The route identifier information RouteID is used to indicate a determined alternative link, and the service type identifier USID is used to indicate whether the base station service adaptation protocol data packet is the data packet corresponding to the crosslink communication data.

[0093] After the service data arrives at the UCM entity in the crosslink data transmission layer, the UCM entity adds a header to the service data to obtain a PDU, and then submits the PDU to the HDAP entity of the lower layer entity. The HDAP entity then sends the PDU to the SADP entity of the terminal device to complete the transmission. When the HSAP entity of the base station device generates the PDU corresponding to the HDAP layer, it can generate the downlink HDAP PDU according to the PDU format shown in Table 4 below: Table 4. Schematic diagram of HDAP PDU format from base station equipment to terminal equipment

[0094] RQI indicates whether NAS signaling can carry changes to QoS mapping rules. RDI indicates whether there are changes to the mapping rules between QoS flows and radio data bearers (DRBs). QFI is the QoS classification ID corresponding to the HDAP PDU. RDI, RQI, and QFI can be used to determine whether the received data is crosslinked communication data. As an example, if RDI=0, RQI=0, and QFI=127, it indicates that the received data is crosslinked communication data.

[0095] Since the Serving Data Protocol Adaptation Layer (HDAP) of the terminal device and the Serving Data Protocol Adaptation Layer of the base station device are connected via Uu, when the HDAP entity of the terminal device sends an uplink PDU to the HSAP entity of the base station device, the HDAP of the terminal device needs to generate the corresponding uplink HDAP PDU according to the PDU format shown in Table 5 below: Table 5. Schematic diagram of HSAP PDU format for uplink from terminal equipment to base station equipment

[0096] If the terminal device fills in 1 in position H, it means that the data PDU is cross-connect communication data.

[0097] In this embodiment, the data recorded by the CM entity can also be transferred to the lower-layer HDAP entity. Then, the HDAP entity is notified through inter-layer primitives to generate the corresponding HDAP PDU according to the PDU format shown in Tables 2 and 3 above. Specifically, after the service data arrives at the CM entity in the crosslink data transmission layer, the CM entity adds a packet header according to the data packet header shown in Table 2, and then sends the PDU with the added header to the lower-layer HDAP entity. At the same time, a first timer T1000 is set to wait for the receive response message from the CM entity corresponding to the second base station device, that is, to wait for the CM entity corresponding to the second base station device to send back the receive response message sent in the PDU format shown in Table 3 above.

[0098] Before the first timer T1000 terminates, it waits for a receive acknowledgment message for cross-connection service data sent by the second base station device to confirm whether the sent PDU has been correctly received. If T1000 terminates without receiving a receive acknowledgment message from the second base station device, it indicates that the previously sent data packets were lost, and the previously sent PDU needs to be retransmitted. If at least one receive acknowledgment message for a data packet or at least one receive confirmation instruction for a data packet is received during the operation of the first timer T1000, the first timer T1000 can be reset to its initial value. For data packets that have received confirmation instructions, transmission can be completed; for data packets that have not received confirmation, it is necessary to continue waiting for confirmation from the second base station device.

[0099] Because business data has certain transmission time requirements, and the product cannot indefinitely cache unacknowledged data, a sending window can be set in the CM entity under CM mode to limit the number of consecutively sent data packets. For example, if the sending window is set to 10, it means that 10 data packets can be sent consecutively. This means that the CM sending sub-entity of the first base station device can send 10 data packets consecutively and then wait for the reception response message from the second base station device. If the reception response message or acknowledgment instruction for one of the data packets arrives, a sliding window mechanism can be used to continue sending one more data packet to the second base station device.

[0100] In this embodiment, since the alternative link is composed of multiple Zt connections between multiple terminal devices, the jitter of the entire wireless link increases with the increase in the number of Zt connections. Therefore, as an implementation, the CM entity can be configured with an optional retransmission mechanism. This optional retransmission mechanism stipulates that if a sending window is used to send data packets, it is necessary to wait for all data packets corresponding to the sending window to receive an acknowledgment instruction before the window can slide; otherwise, the window cannot be moved. If the first timer T1000 has not yet terminated, the CM entity can force the retransmission of the data packets with the corresponding sequence number that the second base station device has not yet received, and notify the second base station device that the sequence number of the next received data packet will start counting from the data packet with the currently received maximum sequence number SN+1.

[0101] For example, if a number of data packets equal to the window size were sent in the previous moment, such as 10 data packets with sequence numbers 0 to 9, and data packets with sequence numbers 1 to 9 have all been received, but the acknowledgment instruction for packet number 0 has not been received, the window cannot be moved, and T1000 still has a long time to expire, the CM entity can forcibly retransmit data packet number 0 and notify the other end that the sequence number of the next received data packet will start from 10.

[0102] Based on this optional retransmission mechanism, as one implementation method, after the CM receiving sub-entity in the first base station device receives a data packet from the lower-level entity, it starts the second timer T1001 and checks the SN sequence number in the packet header to confirm whether the data packet is a newly transmitted data packet. If so, it checks the current window and records the window value corresponding to the packet sequence number as "received". If all data packets in the current window have been received, it moves the window start value to the packet sequence number SN of the next data packet that should be received, restarts the second timer T1001, and sends a receive acknowledgment message to the CM sending sub-entity corresponding to the second base station device. This receive acknowledgment message carries an acknowledgment instruction, which informs the second base station device to confirm the packet sequence number SN of the last data packet received.

[0103] The CM receiving sub-entity detects that the received data packet is an acknowledgment packet sent by the second base station device, indicating that the data packet has been received correctly. Specifically, the sequence number of the correctly received data packet can be determined based on the ACK SN field, indicating that all data packets before that SN have been correctly received. The sequence number of the incorrectly received or lost data packet can be confirmed based on the NACK SN field. The CM receiving sub-entity can then submit the ACK SN and NACK SN to the CM sending sub-entity, which will then send a new data packet or retransmit the old data packet.

[0104] In this embodiment, after a link switch, the receiving target of the data packet in the crosslink data transmission layer changes from the second base station device to the first terminal device. After the UCM and CM entities in the crosslink data transmission layer perform the above steps of adding and removing headers, they submit the corresponding PDU to the Base Station Service Adaptation Protocol (HDAP) entity. The HDAP entity adds a header to obtain the corresponding HDAP PDU, which is then transmitted to the HDAP entity of the first terminal device via the Uu connection between the first base station device and the first terminal device. To ensure that the HDAP entity of the first terminal device knows that the received HDAP PDU is a ZTAP entity to be submitted to the first terminal device, the first base station device needs to add an indicator bit to the header of the received HDAP PDU data packet. This indicator bit indicates that the receiving target entity is a ZTAP entity, and not any other entity of the first terminal device.

[0105] The HDAP PDU header format can be based on Tables 2, 3, and 5 above, with the addition of an indicator bit, where an additional byte represents this indicator bit. If RDI=0, RQI=0, and QFI=127, bits 0-3 of the second byte of the PDU represent the route ID, and bits 4-7 represent the QoS requirements of the service data, corresponding to the USID. Then, the first base station device fills in the corresponding HDAP PDU field H based on the route ID value in the crosslink service data, for example, Route ID=1. Thus, when the first terminal device receives an HDAP PDU data packet, it can determine whether the HDAP PDU belongs to crosslink communication data that needs to be relayed through a direct connection between terminal devices based on the bit content of the first byte.

[0106] The above describes the actions performed during link switching at the crosslink data transmission layer. The following section will explain the actions performed by the first terminal device after receiving the HDAP PDU from the HDAP entity of the first base station device: When the first terminal device receives an uplink service data HSAP PDU that needs to be sent to the first base station device, the first terminal device fills in Hbit=1 in the H field of the packet header. Hbit=1 can inform the first base station device that the HDAP PDU submitted by the first terminal device is crosslink transport layer data. After receiving the HDAP PDU, the HSAP entity of the first base station device can determine whether the PDU needs to be uploaded to the upper crosslink data transmission layer entity based on the H field. If the H field content is Hbit=1, it can be determined that the packet header of the HDAP PDU needs to be removed to obtain the SDU, and the SDU needs to be submitted to the entity in the crosslink data transmission layer.

[0107] In this process, after receiving communication data sent by the first base station device and reaching the HDAP layer, the first terminal device can determine whether the received data packet is a crosslink communication data packet based on the RDI, RQI, and QFI fields in the data packet header. For example, if RDI=0, RQI=0, and QFI=127, it indicates that the received data packet is a crosslink communication data packet and needs to be forwarded through the Zt link between ZTAPs. In this case, the crosslink communication data packet can be forwarded to the ZTAP entity layer. The ZTAP entity layer then determines the next-hop terminal device based on the RouteID and USID specified in the second byte of the HDAP data packet. This next-hop terminal device can be a third terminal device or a second terminal device, depending on the RouteID.

[0108] The first terminal device, HDAP entity, obtains the cross-connection communication data SDU after removing the header from the received PDU, and then forwards the SDU to the ZTAP entity indicated by RouteID and USID. The ZTAP entity then adds a header according to the ZTAP PDU format shown in Table 6 below: Table 6. Schematic diagram of ZTAP PDU format for a direct connection link of a terminal device.

[0109] When the ZTAP entity in the first terminal device adds a packet header, the RouteID is consistent with the RouteID of the received SDU, and the USID is changed to the relay service ID. Different USID values ​​can distinguish between crossover services and relay services. Then, the ZTAP entity delivers the data packet to the lower-level entity, which ultimately generates a wireless signal and sends it to either the third terminal device (if a third terminal device exists, it is sent to the third terminal device) or the second terminal device (if the first terminal device and the second terminal device are directly connected, it is sent directly to the second terminal device).

[0110] When the first terminal device receives a data packet sent by the third terminal device, it is sent layer by layer from the lower-level entities (physical layer, MAC, PDCP, etc.) of the first terminal device to the ZTAP layer of the first terminal device. The ZTAP layer, based on the RouteID, USID, and the relationship with the HSAP entity of the first base station device, delivers the received data packet to the HDAP entity of the first terminal device. After the HDAP entity of the first terminal device receives the data packet from the ZTAP entity, it adds a packet header and sets an indicator bit in the H field of the data packet header, such as Hbit=1, to indicate that after this HDAP PDU packet arrives at the HSAP layer of the first base station device, the data packet can be confirmed as crosslink communication data based on Hbit=1, and the crosslink communication data needs to be delivered to the entity of the crosslink data transmission layer.

[0111] The third terminal device receives the wireless signal from the physical layer, which is directly connected to the first terminal device. After processing through the physical layer, MAC layer, RLC layer, and PDCP layer, the signal arrives at the ZTAP entity of the third terminal device. The ZTAP entity of the third terminal device obtains the ZTAP PDU and then determines the ZTAP layer entity corresponding to the next-hop terminal device to which the data packet should be forwarded based on the RouteID and USID in the packet header information. The ZTAP PDU is then forwarded to the ZTAP layer entity corresponding to the next-hop terminal device (which can be another third terminal device or a second terminal device). The third terminal device includes two ZTAP entities: a ZTAP receiving sub-entity and a ZTAP transmitting sub-entity. The ZTAP receiving sub-entity processes the data PDU between the first-hop terminal device and the previous-hop terminal device, while the ZTAP transmitting sub-entity processes the data PDU between the next-hop terminal device and the previous-hop terminal device. For example, ZTAP-31 can be used to identify the ZTAP receiving sub-entity in the third terminal device that processes data PDUs between the previous hop first terminal device, and ZTAP-32 can be used to identify the ZTAP sending sub-entity in the third terminal device that processes data PDUs sent to the second terminal device.

[0112] If the next-hop device of the third terminal device happens to be the second terminal device, the ZTAP entity of the third terminal device needs to continue forwarding. Therefore, the ZTAP receiving sub-entity of the third terminal device can forward the data packet directly to the ZTAP sending sub-entity without modifying the content of the data packet. Then, the ZTAP sending sub-entity delivers the data packet to the next layer, and finally forms a wireless signal to be sent to the second terminal device.

[0113] The processing of data received by the third terminal device from the second terminal device is the same as the processing of data received by the third terminal device from the first terminal device. The processing of received data and the data forwarding process of the second terminal device are the same as those of the first terminal device, and will not be described again here.

[0114] When the second base station device acts as the receiver, it receives the HDAP data packet from the second terminal device, then parses the packet header to obtain the indicator bit (Hbit) carried in the packet header. Based on this indicator bit, it determines whether the received HDAP data packet is a crosslink communication data packet. If Hbit=1, the HDAP data packet is confirmed to be crosslink communication data. After removing the HDAP packet header, the HDAP data packet is submitted to the crosslink data transmission layer. The crosslink data transmission layer determines whether the data packet belongs to the unacknowledged mode PDU or the acknowledged mode PDU based on the PDU format. Then, it selects the corresponding UCM receiving sub-entity or CM receiving sub-entity for processing. The specific processing procedures of the UCM receiving sub-entity and CM receiving sub-entity are described in the previous text and will not be repeated here.

[0115] If the second base station device needs to send data, it can refer to the sending logic of the first base station device, which will not be elaborated here.

[0116] By employing the embodiments of this application, when a crosslink between base station devices is interrupted, an alternative link can be quickly identified. The crosslink communication data is then forwarded to the corresponding base station device via the alternative link, which utilizes multi-hop forwarding by the terminal device. By adding a crosslink data transmission layer to the base station device to process the crosslink communication data, seamless link switching for upper-layer applications can be achieved, thereby enabling the transmission of crosslink communication data with free switching between multiple link modes.

[0117] Based on the method provided in the first aspect, and in a third aspect, this application provides a base station device, wherein, as shown in the first aspect, it can... Figure 9 As shown, the base station equipment 90 includes: The base station control module 901 is used to construct a crosslink based on the first crosslink data transmission layer and the second crosslink data transmission layer. The cross-link data transmission module 902 is used to send and / or receive cross-link communication data through the cross-link.

[0118] Based on the method provided in the second aspect, in the fourth aspect, this application provides a base station device, wherein, similarly, Figure 9 As shown, the base station equipment 90 includes: The base station control module 901 is used to determine an alternative link if the cross link between the base station and the second base station is interrupted. The alternative link is constructed by a number of terminal devices, each of which includes a first terminal device, a second terminal device, and a third terminal device, wherein the first terminal device is directly connected to the first base station, the second terminal device is directly connected to the second base station, and the third terminal device is a terminal device that is not directly connected to the first base station or the second base station. The cross-connect data transmission module 902 is used to send cross-connect communication data, where the destination base station device is the second base station device, to the second base station device through the alternative link, and to receive data returned by the second base station device based on the alternative link.

[0119] The names of the messages or information exchanged between multiple devices in the embodiments of this application are for illustrative purposes only and are not intended to limit the scope of these messages or information.

[0120] Fifthly, exemplary embodiments of this application also provide an electronic device, including: at least one processor; and a memory communicatively connected to the at least one processor. The memory stores a computer program executable by the at least one processor, the computer program being executed by the at least one processor to cause the electronic device to perform a method according to an embodiment of this application.

[0121] In a sixth aspect, exemplary embodiments of this application also provide a non-transitory computer-readable storage medium storing a computer program, wherein the computer program, when executed by a computer's processor, is used to cause the computer to perform a method according to an embodiment of this application.

[0122] In a seventh aspect, exemplary embodiments of this application also provide a computer program product, including a computer program, wherein, when executed by a processor of a computer, the computer program is used to cause the computer to perform a method according to an embodiment of this application.

[0123] refer to Figure 10The present invention describes a structural block diagram of an electronic device 1000 that can serve as a server or client of this application, which is an example of a hardware device that can be applied to various aspects of this application. The electronic device is intended to represent various forms of digital electronic computer devices, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the application described and / or claimed herein.

[0124] like Figure 10 As shown, the electronic device 1000 includes a computing unit 1001, which can perform various appropriate actions and processes according to a computer program stored in a read-only memory (ROM 1002) or a computer program loaded from a storage unit 1008 into a random access memory (RCM 1003). The RCM 1003 may also store various programs and data required for the operation of the electronic device 1000. The computing unit 1001, ROM 1002, and RCM 1003 are interconnected via a bus 1004. An input / output interface (I / O interface 1005) is also connected to the bus 1004.

[0125] Multiple components in electronic device 1000 are connected to I / O interface 1005, including: input unit 1006, output unit 1007, storage unit 1008, and communication unit 1009. Input unit 1006 can be any type of device capable of inputting information to electronic device 1000. Input unit 1006 can receive input digital or character information and generate key signal inputs related to user settings and / or function control of electronic device. Output unit 1007 can be any type of device capable of presenting information and may include, but is not limited to, a display, speaker, video / audio output terminal, vibrator, and / or printer. Storage unit 1008 may include, but is not limited to, disk and optical disk. Communication unit 1009 allows electronic device 1000 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks, and may include, but is not limited to, modems, network cards, infrared communication devices, wireless communication transceivers, and / or chipsets, such as Bluetooth™ devices, WiFi devices, WiMax devices, cellular communication devices, and / or the like.

[0126] The computing unit 1001 can be various general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of the computing unit 1001 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. The computing unit 1001 performs the various methods and processes described above. For example, in some embodiments, the aforementioned data transmission method for multi-type emergency communication link networking can be implemented as a computer software program, which is tangibly contained in a machine-readable medium, such as storage unit 1008. In some embodiments, part or all of the computer program can be loaded and / or installed on the electronic device 1000 via ROM 1002 and / or communication unit 1009. In some embodiments, the computing unit 1001 can be configured to perform the aforementioned data transmission method for multi-type emergency communication link networking by any other suitable means (e.g., by means of firmware).

[0127] The program code used to implement the methods of this application may be written in any combination of one or more programming languages. This program code may be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing device, such that when executed by the processor or controller, the functions / operations specified in the flowcharts and / or block diagrams are implemented. The program code may be executed entirely on a machine, partially on a machine, as a standalone software package partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0128] In the context of this application, a machine-readable medium can be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. Machine-readable media can be, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RCM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0129] As used in this application, the terms "machine-readable medium" and "computer-readable medium" refer to any computer program product, device, and / or apparatus (e.g., disk, optical disk, memory, programmable logic device (PLD)) for providing machine instructions and / or data to a programmable processor, including machine-readable media that receive machine instructions as machine-readable signals. The term "machine-readable signal" refers to any signal for providing machine instructions and / or data to a programmable processor.

[0130] To provide interaction with a user, the systems and techniques described herein can be implemented on a computer having: a display device for displaying information to the user (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor); and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the computer. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0131] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as a data server), or computing systems that include middleware components (e.g., an application server), or computing systems that include frontend components (e.g., a user computer with a graphical user interface or web browser through which a user can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., a communication network). Examples of communication networks include local area networks (LANs), wide area networks (WANs), and the Internet.

[0132] Computer systems can include clients and servers. Clients and servers are generally located far apart and typically interact through communication networks. Client-server relationships are created by computer programs running on the respective computers and having a client-server relationship with each other.

Claims

1. A data transmission method for emergency communication multi-type link networking, characterized in that, The method is applied to a first base station device or a second base station device. The communication protocol stack of the first base station device includes a first crosslink data transmission layer, and the communication protocol stack of the second base station device includes a second crosslink data transmission layer. The method includes: A crosslink is constructed based on the first crosslink data transmission layer and the second crosslink data transmission layer; Transceive and / or receive transceiver communication data via the transceiver link.

2. The data transmission method according to claim 1, characterized in that, The crosslink data transmission layer includes: an unacknowledged mode entity and an acknowledged mode entity. Sending and / or receiving crosslink communication data through the crosslink data transmission layer includes: The cross-connection communication data is sent and / or received through the unacknowledged mode entity, or the cross-connection communication data is sent and / or received through the acknowledged mode entity.

3. The data transmission method according to claim 2, characterized in that, The unacknowledged mode entity includes: an unacknowledged mode sending entity and an unacknowledged mode receiving entity. Sending and / or receiving the cross-connection communication data through the unacknowledged mode entity includes: The cross-connection communication data is sent by the entity in the non-acknowledgment mode, or received by the entity in the non-acknowledgment mode.

4. The data transmission method according to claim 2, characterized in that, The acknowledgment mode entity includes: an acknowledgment mode sending entity and an acknowledgment mode receiving entity. Sending and / or receiving the cross-connection communication data through the acknowledgment mode entity includes: The entity sending the cross-connection communication data sends the cross-connection communication data through the confirmation mode, or the entity receiving the cross-connection communication data receives the cross-connection communication data through the confirmation mode.

5. The data transmission method according to claim 2, characterized in that, The method further includes: If the cross-connection communication data corresponds to the first-level packet loss rate constraint, then the cross-connection communication data is sent and / or received through the confirmation mode entity; If the cross-connection communication data corresponds to the second-level packet loss rate constraint, then the cross-connection communication data is sent and / or received through the unacknowledged mode entity. Wherein, the first packet loss rate constrained by the first-level packet loss rate constraint is less than the second packet loss rate constrained by the second-level packet loss rate constraint.

6. The data transmission method according to claim 4, characterized in that, The step of sending the cross-connect communication data through the confirmation mode includes: The acknowledgment mode sending entity adds an acknowledgment mode data packet header to the cross-connection communication data to obtain a first data packet to be sent. Send the first data packet to be sent to the second base station device, start the first timer and listen for the cross-connection communication data reception response message sent by the second base station device; If the first timer terminates and no response message for receiving the cross-connection communication data is received, then the first data packet to be sent is resent to the second base station device; If the first timer receives a cross-connection communication data reception response message during its operation, the duration of the first timer is reset to its initial value.

7. The data transmission method according to claim 4, characterized in that, The step of receiving the cross-connect communication data through the confirmation mode includes: If the acknowledgment mode receiving entity receives a data packet sent by the lower-level entity, it starts a second timer; If all data packets of cross-connection communication data are received during the operation of the second timer, then the second timer is restarted.

8. The data transmission method according to claim 3, characterized in that, The step of sending the cross-connect communication data through the unacknowledged mode sending entity includes: The non-confirmed mode sending entity adds a non-mode data packet header to the cross-connection communication data to obtain a second data packet to be sent; The second data packet to be sent is sent to the unacknowledged receiving entity of the second base station device.

9. A data transmission method for multi-type link networking in emergency communication, characterized in that, The method is applied to a first base station device or a second base station device. The communication protocol stack of the first base station device includes a first crosslink data transmission layer, and the communication protocol stack of the second base station device includes a second crosslink data transmission layer. The method includes: If the cross link between the device and the second base station is interrupted, an alternative link is determined. The alternative link is constructed by a number of terminal devices, each of which includes: a first terminal device, a second terminal device, and a third terminal device, wherein: the first terminal device is directly connected to the first base station device, the second terminal device is directly connected to the second base station device, and the third terminal device is a terminal device that is not directly connected to the first base station device or the second base station device. The cross-connection communication data with the target base station device being the second base station device is sent to the second base station device through the alternative link, and the data returned by the second base station device is received based on the alternative link.

10. The method according to claim 9, characterized in that, The communication protocol stack of the base station equipment also includes: a base station crosslink service adaptation layer. The communication protocol stack of the terminal equipment includes: a direct link data application layer. The communication protocol stacks of the first terminal equipment and the second terminal equipment also include: a terminal crosslink service adaptation layer. The base station crosslink service adaptation layer communicates with the terminal crosslink service adaptation layer, and the direct link data application layers communicate with each other.

11. The method according to claim 9, characterized in that, The step of sending cross-connection communication data, where the destination base station device is the second base station device, to the second base station device via the alternative link includes: The cross-link communication data recorded by the cross-link data transmission layer is accessed to the base station cross-link service adaptation layer through inter-layer primitive notification. The cross-connection communication data is sent by the base station cross-connection service adaptation layer to the terminal cross-connection service adaptation layer of the first terminal device, and then forwarded to the terminal cross-connection service adaptation layer of the second terminal device via the direct link data application layer of each terminal device, so that the terminal cross-connection service adaptation layer of the second terminal device forwards the cross-connection communication data to the base station cross-connection service adaptation layer of the second base station device.

12. The method according to claim 11, characterized in that, The step of notifying the access of the base station crosslink service adaptation layer to the crosslink communication data recorded by the crosslink data transmission layer through inter-layer primitives includes: Determine the sequence number of the cross-connection communication data currently received by the second base station device, and determine the protocol data unit to be sent of the cross-connection communication data based on the sequence number; The protocol data unit to be sent is transmitted to the base station data service adaptation protocol layer through the inter-layer primitive notification.

13. The method according to claim 11, characterized in that, The method further includes: The Base Station Service Adaptation Protocol (LSAP) layer packages the cross-connection communication data into a Base Station Service Adaptation Protocol (LSAP) data packet. The data format of the base station service adaptation protocol data packet includes: routing identification information and service type identification. The routing identification information is used to indicate a determined alternative link, and the service type identification is used to indicate whether the base station service adaptation protocol data packet is the data packet corresponding to the crosslink communication data. The base station service adaptation protocol data packet is sent to the terminal crosslink service adaptation layer of the first terminal device.

14. The method according to claim 9, characterized in that, The method further includes: If the crosslink is interrupted, stop sending data packets to the crosslink; The first data packet arriving at the crosslink data transmission layer is cached in the service data cache area, and the second data packet is cached in the initial transmission data cache area. The second data packet is the data packet after the crosslink data transmission layer adds a data packet header to the first data packet.

15. The method according to claim 14, characterized in that, If the second data packet is a data packet with a header added to the acknowledgment mode entity in the crosslink data transmission layer, the method further includes: The third data packet is buffered in the retransmission buffer. The third data packet is the second data packet that has been sent but has not yet received a return reception response message from the second base station device.

16. The method according to claim 9, characterized in that, The method further includes: Using the crosslink data transmission layer, several crosslink communication data packets are sent to the second base station device based on the crosslink, and a receive response message is received back from the crosslink data transmission layer of the second base station device; If the crosslink communication data packet is sent and no confirmation message is received, it is determined that the crosslink has been interrupted.

17. The method according to claim 9, characterized in that, The first terminal device and the first base station device establish a first Uu connection through the Uu interface, the second terminal device and the second base station device establish a second Uu connection through the Uu interface, and the terminal devices establish a direct connection through the terminal direct link interface.

18. A base station device, characterized in that, The base station equipment is either a first base station equipment or a second base station equipment. The communication protocol stack of the first base station equipment includes a first crosslink data transmission layer, and the communication protocol stack of the second base station equipment includes a second crosslink data transmission layer. The base station equipment includes: The base station control module is used to construct a crosslink based on the first crosslink data transmission layer and the second crosslink data transmission layer; A cross-connect data transmission module is used to send and / or receive cross-connect communication data through the cross-connect link.

19. A base station device, characterized in that, The base station equipment is either a first base station equipment or a second base station equipment. The communication protocol stack of the first base station equipment includes a first crosslink data transmission layer, and the communication protocol stack of the second base station equipment includes a second crosslink data transmission layer. The base station equipment includes: The base station control module is used to determine an alternative link if the crosslink between the base station and the second base station is interrupted. The alternative link is constructed by a number of terminal devices, each of which includes a first terminal device, a second terminal device, and a third terminal device, wherein the first terminal device is directly connected to the first base station, the second terminal device is directly connected to the second base station, and the third terminal device is a terminal device that is not directly connected to the first base station or the second base station. The cross-connect data transmission module is used to send cross-connect communication data, where the destination base station device is the second base station device, to the second base station device through the alternative link, and to receive data returned by the second base station device based on the alternative link.

20. An electronic device, characterized in that, The electronic device includes: a processor and a memory storing a program; wherein the program includes instructions that, when executed by the processor, cause the processor to perform the method according to any one of claims 1-8 or 9-17.

21. A non-transitory computer-readable storage medium storing computer instructions, characterized in that, The computer instructions are used to cause the computer to perform the method according to any one of claims 1-8 or 9-17.

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