Communication method, apparatus and system, and vehicle

Abstract

A communication method, apparatus and system, and a vehicle. The method comprises: a first slave node receiving a first discovery frame, which carries a first identifier and first indication information, wherein the first indication information is used for indicating the validity of the first discovery frame; and when the first identifier belongs to a valid slave node identifier set and the first indication information indicates that the first discovery frame is a valid frame, the first slave node sending a first uplink frame, wherein the first uplink frame comprises a second identifier, which belongs to the valid slave node identifier set, and the valid slave node identifier set comprises at least one slave node identifier. The technical solution can be applied to the field of audio and video transmissions, and can increase the speed of discovering a slave node, thereby improving the communication efficiency in an audio and video system.

Description

Communication methods, devices, systems and vehicles Technical Field

[0001] This application relates to the field of audio and video transmission, and more specifically, to a communication method, apparatus, system, and vehicle. Background Technology

[0002] In a vehicle's wired audio-visual system, there is usually a main controller and multiple audio-visual devices. The main controller and the multiple audio-visual devices are usually connected in a daisy-chain network. The main controller sends the audio and video data to be played to one or more audio-visual devices through the audio-visual bus for playback. The audio-visual devices transmit the audio and video data they have collected back to the main controller through the audio-visual bus.

[0003] To enable the transmission of audio and video data between the main controller and the audio and video devices, before data transmission can occur, the slave nodes in multiple audio and video devices need to synchronize their clocks with the master node in the main controller and be discovered by the master node to access the audio and video bus system. When the main controller and multiple audio and video devices are connected in a daisy-chain configuration, how to quickly discover the slave nodes in the audio and video bus system becomes a pressing issue.

[0004] Summary of the Invention

[0005] This application provides a communication method, apparatus, system, and vehicle that can improve the discovery speed of slave nodes, thereby improving the communication efficiency in audio and video systems.

[0006] In a first aspect, a communication method is provided, which is applied to a slave node in an audio-visual system. For example, it can be executed by a chip or circuit of the slave node. The following description takes the execution of this method by a first slave node or a chip or circuit of the first slave node as an example.

[0007] The method includes: receiving a first discovery frame, the first discovery frame carrying a first identifier and first indication information; wherein the first indication information is used to indicate the validity of the first discovery frame; when the first identifier belongs to a set of valid slave node identifiers and the first indication information indicates that the first discovery frame is a valid frame, sending a first uplink frame, the first uplink frame including a second identifier, the second identifier belonging to a set of valid slave node identifiers; wherein the set of valid slave node identifiers includes at least one slave node identifier.

[0008] In some implementations, slave node discovery involves the master node detecting the slave node and assigning it an identity (ID). In other words, the master node assigns a value to the slave node's identity through the slave node discovery process. The slave node identities included in the valid slave node identity set are those used for slave node discovery; that is, these identities can be assigned to slave nodes as slave node identities for use in subsequent communication processes within the audio and video system.

[0009] In some implementations, when the first discovery frame is a valid frame, it indicates that the first identifier in the first discovery frame can be assigned to a slave node that has not been assigned an identifier as its slave node identifier; when the first discovery frame is an invalid frame, it indicates that the first identifier in the first discovery frame has already been used as a slave node identifier of a certain slave node, and it cannot be assigned to a slave node that has not been assigned an identifier.

[0010] In some implementations, the first uplink frame and the first discovery frame are associated. Specifically, the first uplink frame and the first discovery frame have the same frame number and frame type, meaning both are discovery frames. The frame number indicates the order of transmitted frames; for example, the frame number of the first discovery frame indicates its order or sequence among all transmitted frames. The frame number can start from 0 and increment cyclically for each frame. The frame type indicates that both the first uplink frame and the first discovery frame are discovery frames. Furthermore, the second identifier can be the same as the first identifier, or it can be the identifier of the end slave node in the audio / video system.

[0011] In the above technical solution, the first indication information enables the slave node to quickly determine whether the identifier carried in the discovery frame can be assigned to a slave node without an identifier as a slave node identifier. In other words, the slave node can determine whether the first identifier can be assigned to a slave node without an identifier based at least on the field carrying the first indication information and / or the field carrying the first identifier. This helps to reduce the processing complexity of the slave node in the node discovery process, saves the time required for the slave node to process the discovery frame, and thus improves the slave node discovery speed to achieve rapid discovery of slave nodes.

[0012] In conjunction with the first aspect, in some implementations of the first aspect, the method further includes: when the first slave node receives the first discovery frame while in an undiscovered state, sending a second discovery frame, the second discovery frame including second indication information, the second indication information indicating that the second discovery frame is an invalid frame.

[0013] In some implementations, a slave node being in an undiscovered state can mean that the slave node has not set an identifier. In practice, a slave node in an undiscovered state can receive broadcast, multicast, or transparent messages from the master node, but the master node cannot unicast messages to it. Broadcast and multicast refer to one-to-many communication, where the master node sends messages to multiple slave nodes; unicast refers to one-to-one communication, where the master node sends a message to only one slave node.

[0014] In conjunction with the first aspect, in some implementations of the first aspect, the method further includes: setting the first identifier as the identifier of the first slave node. Furthermore, a first uplink frame is determined, wherein the frame number and frame type of the first uplink frame are the same as those of the first discovery frame.

[0015] It should be noted that in this case, the first slave node is the initiating slave node of the first uplink frame. The initiating slave node refers to the source of the uplink frame, that is, the initiating slave node composes and sends the uplink frame. The act of the initiating slave node composing and sending the uplink frame is called initiating the uplink frame. It should also be noted that during the transmission of this uplink frame, the data and / or control information in the uplink frame may change, but the frame number and frame type of the uplink frame remain unchanged.

[0016] In the above technical solution, when the first slave node is in an undiscovered state and the first indication information indicates that the first discovery frame is a valid frame, the first slave node can, according to the first indication information, set the first identifier carried by the first discovery frame as its own identifier, and send the second discovery frame carrying the second indication information to the downlink slave node. This allows the downlink slave node to quickly determine that the discovery frame is an invalid frame based on the second indication information, which helps improve communication efficiency. Furthermore, the slave node determines whether it is the target slave node corresponding to the first discovery frame based on its own state, whether its first identifier is in the set of valid slave node identifiers, and whether the first indication information indicates that the first discovery frame is a valid frame. This helps avoid incorrect feedback from the slave node, which could lead to abnormalities in the slave node discovery process and state.

[0017] In this context, the downlink slave nodes of the first slave node are those slave nodes in the daisy chain that are furthest from the master node relative to the first slave node. If the identifiers assigned to slave nodes during the slave node discovery process are sequentially incremented, then the downlink slave nodes of the first slave node are those slave nodes whose identifiers are larger than the slave node identifier of the first slave node. Correspondingly, the uplink slave nodes of the first slave node are those slave nodes in the daisy chain that are closer to the master node relative to the first slave node; or, slave nodes whose identifiers are smaller than the slave node identifier of the first slave node. It should be noted that assigning slave node identifiers to slave nodes in an incrementing manner helps the master node to more easily determine the number of slave nodes and facilitates the master node's location of one or more slave nodes. For example, when a slave node fails or is interrupted, it allows the master node to quickly locate that slave node.

[0018] In conjunction with the first aspect, in some implementations of the first aspect, the first discovery frame and the second discovery frame have the same frame number and frame type.

[0019] In conjunction with the first aspect, in some implementations of the first aspect, the method further includes: sending a first discovery frame when the first slave node is in a discovered state and the first identifier is different from the identifier of the first slave node.

[0020] In the above technical solution, when the first slave node is in the discovered state, the first slave node directly forwards the first discovery frame, which helps to speed up the discovery of slave nodes in the downlink of the slave node.

[0021] In conjunction with the first aspect, in some implementations of the first aspect, the method further includes: receiving a first uplink frame.

[0022] If the first discovery frame is not used for the discovery of the first slave node, and the first slave node is not the initiating slave node of the first uplink frame, then the first slave node receives the first uplink frame from the slave node of the downlink and forwards it to the master node, so that the master node can quickly receive the response information about the downlink frame.

[0023] In conjunction with the first aspect, in some implementations of the first aspect, the method further includes: when the first slave node is in a discovered state and the first identifier is the same as the identifier of the first slave node, sending a third discovery frame, the third discovery frame including third indication information, the third indication information indicating that the third discovery frame is an invalid frame.

[0024] In this case, the third discovery frame and the first discovery frame have the same frame number and frame type. Furthermore, the initiating slave node of the first uplink frame is the first slave node, to report to the master node that the first identifier has been set to the identifier of a certain slave node.

[0025] It should be noted that when the first slave node is in the discovered state and receives a first discovery frame carrying the same first identifier as its own identifier, and the first indication information indicates that the first discovery frame is a valid frame, it means that the master node has not received the response information indicating that the first identifier has been set as the identifier of the slave node. In this case, the first slave node sends a discovery frame carrying the third indication information to the slave node of the downlink, which enables the slave node of the downlink to quickly determine that the discovery frame is an invalid frame based on the second indication information, which helps to improve communication efficiency.

[0026] In conjunction with the first aspect, in some implementations of the first aspect, the second identifier is the same as the first identifier.

[0027] In the above technical solution, the second identifier is the same as the first identifier, so that the master node can determine that the first identifier has been assigned to the slave node, thereby performing the discovery of the next slave node.

[0028] In conjunction with the first aspect, in some implementations of the first aspect, when the first slave node is in a discovered state, the first slave node is an end slave node, and the identifier of the first slave node is different from the first identifier, the second identifier is the identifier of the first slave node.

[0029] When the first slave node is in the discovered state, and the first slave node has no downlink or no other slave node in the downlink, it means that all slave nodes in the audio and video system have been discovered. At this time, the identification of the end slave node is fed back through the first uplink frame, which helps the master node to determine that the slave node discovery has been completed.

[0030] In conjunction with the first aspect, in some implementations of the first aspect, the first uplink frame indicates that the first identifier has not been assigned to the slave node.

[0031] In some implementations, the first uplink frame indicates that the first identifier has not been assigned to the slave node, and the first uplink frame indicates that the first discovery frame has been successfully received, enabling the master node to determine that the slave node discovery has been completed.

[0032] In conjunction with the first aspect, in some implementations of the first aspect, the first discovery frame includes a control domain and a synchronization domain, the synchronization domain being used for clock synchronization, and the control domain including a first identifier and first indication information.

[0033] In some implementations, when the first slave node is an intermediate slave node, the first slave node also forwards the downlink frame carrying the synchronization field of the first discovery frame to its downlink slave node, so that the downlink slave node can complete clock synchronization.

[0034] In the above technical solution, the first discovery frame also includes information for clock synchronization, which can complete the clock synchronization of the audio and video system during the discovery of slave nodes, improve the efficiency of clock synchronization, and thus speed up the rate at which the master node discovers slave nodes.

[0035] In conjunction with the first aspect, in some implementations of the first aspect, the first uplink frame also includes fourth indication information, which indicates whether the slave node corresponding to the second identifier has correctly received the control field of the first discovery frame.

[0036] It is understandable that when the second identifier is the same as the first identifier, and the first identifier is assigned to the first slave node, the slave node corresponding to the second identifier is the first slave node.

[0037] In conjunction with the first aspect, in some implementations of the first aspect, the synchronization domain includes a first synchronization sequence and a second synchronization sequence, and the method further includes: upon detection of the first synchronization sequence, starting to transmit a first downlink frame, the first downlink frame being associated with a first discovery frame.

[0038] The first downlink frame and the first discovery frame are associated, including: the first downlink frame and the first discovery frame have the same frame number and frame type; or, the first downlink frame is determined based on the first discovery frame.

[0039] In some implementations, if a second synchronization sequence is detected after the first synchronization sequence has been sent, the first slave node continues to forward the second synchronization sequence in the first downlink frame; if no second synchronization sequence is detected after the first synchronization sequence has been sent, the first slave node stops sending the first downlink frame.

[0040] In the above technical solution, the first downlink frame is sent as soon as the first synchronization sequence is detected, which helps to save the time required to transmit the downlink frame, thereby improving the downlink frame transmission efficiency and accelerating the discovery rate of the slave node.

[0041] In conjunction with the first aspect, in some implementations of the first aspect, the first discovery frame also includes fifth indication information, which indicates the uplink frame response time and is used to calculate the time when the uplink frame is initiated.

[0042] Secondly, a communication method is provided, which is applied to the master node in an audio-visual system. For example, it can be executed by the chip or circuit of the master node. The following description takes the execution of this method by the master node or the chip or circuit of the master node as an example.

[0043] The method includes: sending a first discovery frame, the first discovery frame carrying a first identifier and first indication information; wherein, the first indication information is used to indicate the validity of the first discovery frame, the first identifier belongs to a set of valid slave node identifiers, and the set of valid slave node identifiers includes at least one slave node identifier; if no first response frame associated with the first discovery frame is received within a first time period, the first discovery frame is sent again.

[0044] In the above technical solution, if no relevant response information is received after the master node sends a discovery frame, the discovery frame is resent. This helps to improve the robustness of the audio and video system in the process of discovering slave nodes and helps to achieve rapid discovery of slave nodes.

[0045] In conjunction with the second aspect, in some implementations of the second aspect, the method further includes: recording the number of times the first discovery frame is sent when sending the first discovery frame; and sending the first discovery frame again when no first response frame associated with the first discovery frame is received within a first time period, including: sending the first discovery frame again when no first response frame is received within the first time period and the number of times the first discovery frame is sent is less than a number threshold.

[0046] In conjunction with the second aspect, in some implementations of the second aspect, the method further includes: recording the number of times the first discovery frame is sent when sending the first discovery frame; if the first response frame is not received within the first time period and the number of times the first discovery frame is sent is not less than the number threshold, prompting a first message, the first message indicating that the discovery from the node has failed.

[0047] In the above technical solution, when the cumulative number of times the first discovery frame is sent does not exceed the preset threshold, the first discovery frame is retransmitted to obtain a response about the first discovery frame; when the cumulative number of times the first discovery frame is sent exceeds the preset threshold, the first information is prompted so that the engineer can inspect the audio and video system, which helps to resolve the faults in the audio and video system in a timely manner.

[0048] In conjunction with the second aspect, in some implementations of the second aspect, the method further includes: stopping the transmission of discovery frames when an identifier has been assigned to all slave nodes in the system, including the master node and the first slave node.

[0049] In some implementations, the master node, based on the received instruction, discovers an uplink frame in which the identifier has not been assigned, and determines that all slave nodes have completed the assignment of the identifier.

[0050] Thirdly, a data transmission structure is provided for the process of discovering a node. The data transmission structure includes a first field and a second field. The first field is used to carry a node identifier, and the second field is used to carry first indication information, which indicates the validity of the data transmission structure.

[0051] In conjunction with the third aspect, in some implementations of the third aspect, the data transmission structure further includes a first verification field and a second verification field. The verification information carried by the first verification field is used to verify the content of at least one field, including the first field, and the verification information carried by the second verification field is used to verify the content of at least one field, including the second field.

[0052] In conjunction with the third aspect, in some implementations of the third aspect, the data transmission structure also includes a third field, which is used to carry the fifth indication information. The fifth indication information indicates the uplink frame response time, and the uplink frame response time is used to calculate the time when the uplink frame is initiated.

[0053] In conjunction with the third aspect, in some implementations of the third aspect, the data transmission structure includes a control domain and a synchronization domain. The control domain carries control information, and the synchronization domain carries synchronization information, which is used for clock synchronization. Furthermore, both the first and second fields are contained within the control domain.

[0054] Fourthly, a data transmission structure is provided, which includes a slave node identification field and a frame acknowledgment field. The slave node identification field is used to carry the identification of the slave node that initiated the data transmission structure. The frame acknowledgment field is used to carry fourth indication information, which indicates whether the slave node has correctly received the control field of the downlink frame.

[0055] In conjunction with the fourth aspect, in some implementations of the fourth aspect, the data transmission structure also includes a verification field, which carries verification information used to verify the contents of the slave node identifier field and the frame acknowledgment field.

[0056] Fifthly, a communication apparatus is provided, the apparatus including a transceiver unit for performing the method as described in any possible implementation of the first aspect.

[0057] In a sixth aspect, a communication apparatus is provided, the apparatus including a transceiver unit for performing the method as described in any possible implementation of the second aspect.

[0058] A seventh aspect provides a communication device comprising: a memory for storing a computer program; and a processor for executing the computer program stored in the memory, such that the device performs a method as described in any possible implementation of the first aspect.

[0059] Eighthly, a communication device is provided, the device comprising: a memory for storing a computer program; and a processor for executing the computer program stored in the memory, such that the device performs a method as described in any possible implementation of the second aspect.

[0060] In conjunction with aspects five through eight, in certain implementations of any of aspects five through eight, the communication device communicates with other communication devices based on the data transmission structure in any possible implementation of aspect three or four.

[0061] Ninth aspect, an audio-visual system is provided, the system including means as in any possible implementation of the fifth aspect and means as in any possible implementation of the sixth aspect; or, the system including means as in any possible implementation of the seventh aspect and means as in any possible implementation of the eighth aspect.

[0062] In a tenth aspect, a vehicle is provided that includes a system as described in any possible implementation of the ninth aspect.

[0063] Eleventhly, a computer program product is provided, the computer program product comprising: computer program code, which, when the computer program code is run on a computer, causes the computer to perform the method in any possible implementation of the first or second aspect.

[0064] It should be noted that the above-mentioned computer program code can be stored in whole or in part on the first storage medium, wherein the first storage medium can be packaged together with the processor or packaged separately from the processor.

[0065] In a twelfth aspect, a computer-readable medium is provided that stores instructions which, when executed by a processor, cause the processor to implement the method in any possible implementation of either the first or second aspect.

[0066] In a thirteenth aspect, a chip is provided, the chip including circuitry for performing the methods in any possible implementation of the first or second aspect described above.

[0067] For the beneficial effects not described in detail in aspects three through thirteen, please refer to the descriptions in aspect one and / or aspect two, which will not be repeated here. Attached Figure Description

[0068] Figure 1 is a schematic block diagram of an audio-visual system provided in an embodiment of this application;

[0069] Figure 2 is another schematic block diagram of the audio and video system provided in the embodiments of this application;

[0070] Figure 3 is a schematic block diagram of the vehicle provided in an embodiment of this application;

[0071] Figure 4 is a schematic flowchart of the communication method provided in an embodiment of this application;

[0072] Figure 5 is a schematic diagram of the frame structure of the downlink frame provided in an embodiment of this application;

[0073] Figure 6 is another schematic diagram of the frame structure of the downlink frame provided in the embodiments of this application;

[0074] Figure 7 is another schematic diagram of the frame structure of the downlink frame provided in the embodiments of this application;

[0075] Figure 8 is a schematic diagram of the frame structure of the uplink frame provided in an embodiment of this application;

[0076] Figure 9 is a schematic diagram of the processing logic of the slave node after receiving the discovery frame according to an embodiment of this application;

[0077] Figure 10 is another schematic flowchart of the communication method provided in the embodiments of this application;

[0078] Figure 11 is another schematic flowchart of the communication method provided in the embodiments of this application;

[0079] Figure 12 is another schematic flowchart of the communication method provided in the embodiments of this application;

[0080] Figure 13 is another schematic flowchart of the communication method provided in the embodiments of this application;

[0081] Figure 14 is a schematic block diagram of a communication device provided in an embodiment of this application;

[0082] Figure 15 is another schematic block diagram of the communication device provided in the embodiments of this application. Detailed Implementation

[0083] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0084] Figure 1 shows a schematic diagram of the audio-visual system provided in an embodiment of this application. As shown in Figure 1, the audio-visual system 100 includes an audio-visual control device 110, an audio-visual device 120, an audio-visual device 130, and an audio-visual device 140. The audio-visual control device 110 includes a main controller 111 and a master node 112; the audio-visual device 120 includes an external device (hereinafter referred to as peripheral) 121 and a slave node 122; the audio-visual device 130 includes a peripheral 131 and a slave node 132; and the audio-visual device 140 includes a peripheral 141 and a slave node 142. The master node 112 is connected to the slave nodes 122, 132, and 142 via cables using a daisy-chain networking method. The slave nodes 122, 132, and 142 can be processors, transmission chips, or other devices in each audio-visual device, respectively. The peripherals 121, 131, and 141 can each include hardware functional modules such as audio-visual decoders, digital-to-analog converters, and analog-to-digital converters in each audio-visual device. The master node 112 is used for communication between the audio / video control device 110 and the audio / video devices 120 to 140. In one example, the master controller 111 sends the audio / video data that needs to be played by the audio / video device 140 to the peripheral device 141 of the audio / video device 140 in sequence through the master node 112, slave node 122, slave node 132, and slave node 142. The peripheral device 141 then performs the playback of the audio / video data. In another example, the audio / video device 130 transmits the audio / video data collected by the peripheral device 131 to the master controller 111 in sequence through the slave node 132, slave node 122, and master node 112.

[0085] In this embodiment, the master node can be a logical unit that manages and controls resources for slave nodes within the link. The slave node can be a logical unit that receives resource management and control from the master node within the link.

[0086] In a link consisting of a master node and one or more slave nodes, a link in which a slave node transmits information to or towards the master node can be called an uplink, and a link in which the slave node transmits information to a slave node farther from the master node can be called a downlink. Furthermore, a link in which the master node transmits information to a slave node is also a downlink. In other words, a data transmission link from the master node to a slave node is a downlink, and a data transmission link from a slave node to the master node is an uplink. For example, slave node 132 can transmit data to slave node 142 via a downlink, and correspondingly, slave node 132 can also receive data from slave node 142 via an uplink. The master node can transmit data to slave nodes 122, 132, and 142 via a downlink, and slave nodes 122, 132, and 142 can transmit data to master node 112 via an uplink. Frames sent by the master node or slave node via a downlink are downlink frames, and frames sent by a slave node via an uplink are uplink frames.

[0087] Figure 2 shows a schematic diagram of the distribution of the audio-visual system provided in this application embodiment in a vehicle. As shown in Figure 2, the audio-visual control device is connected to audio-visual devices 1 to 8 via a daisy-chain network. Audio-visual devices 1 and 3, 3 and 4, 4 and 7, 7 and 8, 8 and 6, 6 and 5, and 5 and 2 can be connected via an in-vehicle audio-visual bus. The audio and video control device may include the audio and video control device 110 shown in FIG1. ​​The audio and video devices 1 to 8 may include one or more of the audio and video devices 120, 130 and 140 shown in FIG1. ​​For example, audio and video device 1 may be the audio and video device 120 shown in FIG1, one or more of audio and video devices 3, 4, 7 and 8 may be the audio and video device 130 shown in FIG1, and one or more of audio and video devices 6, 5 and 2 may be the audio and video device 140 shown in FIG1.

[0088] For example, audio and video devices 1 to 8 may include, but are not limited to: a multimedia head unit, a speaker, a microphone (MIC), and an audio power amplifier (APM).

[0089] Figure 3 shows a functional schematic diagram of a vehicle provided in an embodiment of this application. As shown in Figure 3, the vehicle includes the audio-visual system 100 shown in Figure 1. When the audio-visual system 100 is installed in the vehicle, the audio-visual control device 110 can be installed in at least one of the following: cockpit domain controller (CDC); vehicle domain controller (VDC); and advanced driving domain controller (ADC), or mobile data center (MDC). The cockpit is comprised of several components: CDC (Cockpit Control Unit) and ICAS (Intelligent Cockpit Server). CDC is used to implement intelligent cockpit functions such as human-machine interaction. In practice, CDC may also be called other names, such as Media Graphics Unit (MGU), Intelligent Cockpit Server (ICAS3), or Cockpit Super Core (CSC). VDC (Vehicle Control Unit) is used to implement vehicle control functions. VDC can be seen as an integration of the powertrain domain, chassis domain, and body domain. In practice, VDC may also be called other names, such as Body Domain Controller (BDC), Vehicle Control Server (ICAS1), or Body Super Core (BSC). ADC (Action Control Unit) or MDC (Mechanical Control Unit) is used to implement perception, decision-making, and control functions related to intelligent driving. In practice, ADC or MDC may also be called other names, such as Special Equipment System (SAS), Intelligent Driving Server (ICAS2), or ADAS Super Core. ICAS stands for In-Car Application Server. Alternatively, the audio and video control device 110 can also be located in a central computing platform, for example, the central computing platform may include a vehicle central computer (VCC).

[0090] The main controller 111 and the main node 112 may each include one or more processors in the audio and video control device 110 shown in FIG3, such as processors 201 to 20n (n is a positive integer).

[0091] In other examples, the aforementioned main controller can be a vehicle infotainment system, and the peripheral device can be an audio system or microphone. Accordingly, the node connected to the main controller is the main node, and the node connected to the audio system or microphone is the slave node. The vehicle infotainment system establishes a communication connection with the audio system or microphone to achieve data interaction. Alternatively, the aforementioned main controller can also be a mobile phone, and the peripheral device can be a headset. Accordingly, the node connected to the control components within the mobile phone is the main node, and the node connected to the control components within the peripheral device is the slave node. The mobile phone and the headset establish a communication connection to achieve data interaction. It should be understood that Figures 1 to 3 are merely illustrative examples. In actual implementation, the audio-visual system 100 may include more or fewer slave nodes; that is, the audio-visual system may include more or fewer audio-visual devices.

[0092] As mentioned above, in order to realize the transmission of audio and video data between the main controller and the audio and video devices, each of the multiple audio and video devices needs to be synchronized with the clock of the main controller and discovered before data transmission can be performed, so as to access the audio and video bus system.

[0093] In view of this, embodiments of this application provide a communication method, apparatus, system, and vehicle that improve the efficiency of clock synchronization between multiple slave nodes and the master node during the process of master node discovering slave nodes, thereby accelerating the speed at which the master node discovers slave nodes.

[0094] The specific flow of the communication method provided in the embodiments of this application is described below with reference to Figure 4.

[0095] Figure 4 shows a schematic flowchart of the communication method provided in an embodiment of this application. This method 400 can be executed by the audio / video system 100 shown in Figure 1, or it can be applied to the audio / video system shown in Figure 2. For example, the master node can be the master node 112 in Figure 1, and the slave nodes 1 to 3 can be the slave nodes 122 to 142 in Figure 1, respectively. Specifically, this method 400 may include steps S401 to S421.

[0096] S401, the master node sends discovery frame 1 to slave node 1. Discovery frame 1 carries synchronization information 1 and indication information 1 indicating that discovery frame 1 is a valid frame.

[0097] The discovery frame 1 being a valid frame can be understood as follows: Discovery frame 1 is used for discovering slave nodes. This discovery frame 1 carries an identifier 1 that has not been assigned to any slave node and belongs to the valid slave node identifier set. The valid slave node identifier set contains identifiers that can be assigned to slave node identifiers, or identifiers that can be assigned to slave nodes and used to identify them. For example, it can be used as the initial value of a slave node identifier in an undiscovered state. For example, the valid slave node identifier set can include identifiers with values ​​from 1 to 32. That is, taking a six-bit binary string as an example, the valid slave node identifier set can include identifiers with values ​​from 000001 (decimal 1) to 100000 (decimal 32).

[0098] It is understandable that discovery frame 1 is a downlink discovery frame.

[0099] S402, set identifier 1 from node 1 to its own identifier.

[0100] For example, when slave node 1 is in an undiscovered state, it sets identifier 1 to its own identifier. After slave node 1 is configured with identifier 1, identifier 1 can uniquely identify slave node 1, and the state of slave node 1 changes from undiscovered to discovered.

[0101] It should be noted that, for a slave node, being in an undiscovered state can mean that its slave node identifier has not been assigned a value, i.e., the slave node has not been assigned an identifier. Conversely, being in a discovered state can mean that its slave node identifier has been assigned a value, i.e., the slave node has been assigned an identifier. For a master node, a slave node being in an undiscovered state can mean that the master node has not received a response frame from that slave node, the slave node that initiated the response frame is the aforementioned slave node, the response frame indicates that the identifier in the discovery frame has been assigned, and the response frame has the same frame number and frame type as the discovery frame. Conversely, a slave node being in a discovered state can mean that the master node has received a response frame from that slave node.

[0102] S403, Node 1 sends a discovery frame 2 carrying synchronization information 1 to Node 2.

[0103] Among some possible implementations, it was found that frame 2 could carry only synchronization information 1.

[0104] For example, discovery frame 1 includes a synchronization field and a control field, wherein the synchronization field is used to carry synchronization information 1, and the control field is used to carry identifier 1. Discovery frame 2 may only carry the synchronization field from discovery frame 1, without carrying the control field, and the content of the synchronization field may be the same as the content of the synchronization field in discovery frame 1.

[0105] In some possible implementations, discovery frame 2 can carry synchronization information 1 and indication information a. Indication information a indicates that discovery frame 2 is an invalid frame. An invalid discovery frame can be understood as follows: for the slave node receiving the discovery frame, the discovery frame is not used to assign an identifier to that slave node; or, the discovery frame is not used to assign an identifier to the slave node. For example, the discovery frame does not carry an identifier that has not been assigned to a slave node, or the slave node identifier carried in the discovery frame has already been assigned to a slave node.

[0106] Specifically, instruction information a is obtained from node 1 based on instruction information 1.

[0107] In one example, if indication information 1 is identifier 1, then indication information a can be a special identifier, which can be a specific value, such as a specific value that cannot be assigned to a slave node as an identifier. As shown in Figure 5, discovery frame 1 can include an identifier field, which can carry identifier 1. Furthermore, the shaded area shown in Figure 5 can carry synchronization information 1. As mentioned above, if indication information 1 can be identifier 1 and indication information a can be a special identifier, such as the preset string "111111", then the structure of discovery frame 2 can also be as shown in Figure 5, except that the identifier field of discovery frame 2 carries the preset string "111111".

[0108] In another example, the field of bearing indication information 1 (such as field a) and the field of bearing identifier 1 are independent fields. The value of field a can be a first value or a second value. The first value indicates that the discovered frame is a valid frame, and the second value indicates that the discovered frame is an invalid frame. Therefore, indication information 1 can be the first value, and indication information 2 can be the second value.

[0109] For the latter example mentioned above, uplink frame 1 may include an identification field and a frame validity field (i.e., field a). The identification field carries the identifier 1, and the frame validity field carries the indication information 1. For example, the frame validity field can carry 1 bit of information; a value of "1" for the frame validity field can be considered an example of the aforementioned first value, and a value of "0" for the frame acknowledgment field can be considered an example of the aforementioned second value. As shown in Figure 6, discovery frame 1 may include an identification field and a frame validity field. The identification field can carry the identifier 1, and the frame validity field can carry the indication information 1 indicating that the discovery frame is a valid frame. Furthermore, the shaded area shown in Figure 6 can carry synchronization information 1.

[0110] For example, discovery frame 1 may also include verification information 1, which is used to verify the identification field; when discovery frame 1 includes a frame validity field, verification information 1 may also be used to verify the frame validity field.

[0111] For example, as shown in Figures 5 and 6, the discovery frame can also carry other information fields, which are used to carry information other than synchronization information and identification, such as control information. The control information may include information indicating the time interval for the slave node to send uplink frames.

[0112] In some implementations, the specific frame structure of the control field of the discovery frame can be as shown in Figure 7. This discovery frame includes 8 bytes. Specifically, the first byte carries the frame number (4 bits) and frame type (3 bits). The second byte carries the slave node identifier (6 bits), which can be an identifier assigned to the slave node or an identifier already assigned to the slave node. The third byte carries the uplink frame response time, which is used by the slave node to calculate the time to initiate the uplink frame. The fifth and sixth bytes carry verification information to check the content of the first three bytes. The last bit of the seventh byte is the frame validity field. The eighth byte carries verification information to check the information in the sixth and seventh bytes. For example, the aforementioned verification information can be cyclic redundancy check (CRC) information, etc.

[0113] For example, the slave node determines a first duration based on the uplink frame response time. After the slave node forwards a valid discovery frame to its downlink slave node, if the slave node does not receive a response frame for the discovery frame from its downlink slave node within the first duration starting from the forwarding of the discovery frame, then the slave node initiates a response frame for the discovery frame.

[0114] More specifically, if a slave node has not received an uplink frame from a slave node in the downlink at the uplink response time, it initiates an uplink frame. The slave node initiating an uplink frame should conform to the following rules:

[0115] The slave node should not initiate an uplink frame before the uplink frame response time configured by the master node arrives.

[0116] After the uplink frame response time configured by the master node arrives, if the slave node correctly receives one of the downlink frame synchronization field, control field, or data field, the slave node should start timing from the start position of the downlink frame.

[0117] It should be noted that, in this application, the correct receipt of a transmission frame, or a field of a transmission frame, by a node can be understood as the node fully acquiring the information carried in the transmission frame or a field of the transmission frame. For example, when a node can determine that a checksum has passed based on the checksum information corresponding to a field of the transmission frame, the node can confirm that it has fully acquired the information carried in that field. Furthermore, if an uplink frame is received before the uplink frame response time arrives, the slave node should not initiate an uplink frame; if no uplink frame is received when the uplink frame response time arrives, the slave node should initiate an uplink frame when the uplink frame response time arrives; the frame type of the uplink frame initiated by the slave node should be determined sequentially according to the following rules:

[0118] 1) If the downlink frame control field is received correctly, the frame type of the uplink frame should be the same as that of the downlink frame;

[0119] 2) If the downlink frame control field is not received correctly, but the downlink frame data field is received correctly, then the frame type for initiating the uplink frame should be a data frame.

[0120] 3) If the downlink frame control field and data field are not received correctly, the frame type of the uplink frame should be the same as the frame type of the most recently received uplink frame.

[0121] The master node configures the uplink frame response time for each slave node via downlink discovery frames. For example, the uplink frame response time for each slave node can be calculated according to steps a) to e) to ensure that, in non-sleep mode, only one slave node initiates an uplink frame within each superframe. Slave nodes can support adaptive adjustment of the uplink frame response time. If a slave node supports this adaptive adjustment capability, the adjustment amount and behavior of the uplink frame response time can be completed automatically by the slave node itself.

[0122] a) First step, recursively calculate the downlink time:

[0123] T1Ds = C1d;

[0124] T2Ds = T1Ds + S1Dd + C2d;

[0125] T3Ds = T2Ds + S2Dd + C3d;

[0126] T4Ds = T3Ds + S3Dd + C4d;

[0127] T5Ds = T4Ds + S4Dd + C5d.

[0128] Where TiDs is the start time of the i-th node receiving the downlink frame, i.e., the time corresponding to bit 0 of the downlink frame synchronization field; SiDd is the downlink frame forwarding processing time of the i-th node, which is 20 bits; Cid is the cable transmission delay between the i-th node and the (i-1)-th node, which is 5 ns / m. It should be noted that when i = 1, C1d represents the transmission delay between the first slave node and the master node.

[0129] b) Second step, recursively calculate the relative uplink time:

[0130] T5Us' = 0;

[0131] T4Us' = T5Us' + S4Ud + C5d;

[0132] T3Us' = T4Us' + S3Ud + C4d;

[0133] T2Us' = T3Us' + S2Ud + C3d;

[0134] T1Us'=T2Us'+S1Ud+C2d.

[0135] Where TiUs' is the relative time between the i-th node receiving the uplink frame and the i-th node receiving the downlink frame; SiUd is the uplink frame forwarding processing time of the i-th node, which is 20 bits; and Cid is the cable transmission delay between the i-th node and the (i-1)-th node, which is 5 ns / m.

[0136] c) The third step is to calculate the minimum uplink and downlink latency required for each node:

[0137] Tx1 = T1De - T1Us' + TtransS1;

[0138] Tx2 = T2De - T2Us' + TtransS2;

[0139] Tx3 = T3De - T3Us' + TtransS3;

[0140] Tx4 = T4De - T4Us' + TtransS4;

[0141] Tx5 = T5De - T5Us' + TtransS5;

[0142] Tx=max(Tx1, Tx2, Tx3, Tx4, Tx5).

[0143] Where Txi is the earliest time when the i-th node can receive the uplink frame; TiDe is the end time of the downlink frame of the i-th node; TransSi is the minimum time for the i-th node to switch between receiving and transmitting; and Tx is the time when the node that receives the uplink frame latest among all nodes receives the uplink frame.

[0144] d) Fourth step, calculate the uplink time:

[0145] T1Us = T1Us' + Tx;

[0146] T2Us = T2Us' + Tx;

[0147] T3Us = T3Us' + Tx;

[0148] T4Us = T4Us' + Tx;

[0149] T5Us = T5Us' + Tx.

[0150] Where TiUs is the time when the i-th node receives the uplink frame;

[0151] e) Fifth step: Calculate the uplink response time configuration value:

[0152] respS1 = T1Us - T1Ds;

[0153] respS2 = T2Us - T2Ds;

[0154] respS3 = T3Us - T3Ds;

[0155] respS4 = T4Us - T4Ds;

[0156] respS5 = T5Us - T5Ds.

[0157] Where respSi is the uplink frame response time of the i-th node.

[0158] S404, Node 2 sends discovery frame 2 carrying synchronization information 1 to Node 3.

[0159] For example, when node 2 determines that discovery frame 2 is an invalid frame, it can forward discovery frame 2 to node 3.

[0160] In some implementations, slave node 2 synchronizes its clock using synchronization information 1 and forwards discovery frame 2 to slave node 3.

[0161] S405, Node 1 sends uplink frame 1 to the master node.

[0162] For example, uplink frame 1 indicates that slave node 1 has set identifier 1 to its own identifier, or that slave node 1 has set identifier 1 to its own identifier and has completed clock synchronization. Furthermore, uplink frame 1 indicates that slave node 1 has correctly received the information in the control field of discovery frame 1. Upon receiving uplink frame 1, the master node determines that slave node 1 is in a discovered state, thus completing the discovery of slave node 1. Here, the initiating slave node of uplink frame 1 is slave node 1, and the frame number and frame type of uplink frame 1 are the same as discovery frame 1. It can be understood that uplink frame 1 is a response frame sent by slave node 1 to the master node in response to discovery frame 1; that is, this type of uplink frame can also be called an uplink discovery response frame (hereinafter referred to as a response frame).

[0163] For example, the specific frame structure of the control field of uplink frame 1 can be shown in Figure 8. This uplink frame includes 8 bytes. Specifically, the first byte is used to carry the frame number (4 bits) and frame type (3 bits). The second byte is used to carry the slave node identifier (6 bits) and frame acknowledgment information (1 bit). It should be noted that the frame number, frame type, and slave node identifier of the uplink frame must be consistent with its corresponding downlink frame. The correspondence between the uplink frame and the downlink frame can be understood as: the uplink frame is a response frame to the downlink frame. The aforementioned frame acknowledgment information is used to indicate whether the slave node corresponding to the slave node identifier has correctly received the information in the control field of the downlink frame. For example, when the frame acknowledgment field value is 0, it indicates that the slave node has not correctly received the information in the control field of the downlink frame; when the frame acknowledgment field value is 1, it indicates that the slave node has correctly received the information in the control field of the downlink frame. The third byte is a reserved byte. The fourth and fifth bytes are used to carry verification information, which is used to verify the information in the first three bytes. The sixth and seventh bytes are used to carry interrupt-related information. Specifically, the sixth byte carries the identifier (6 bits) of the slave node that initiated the interrupt and the interrupt request information (1 bit), and the seventh byte carries the interrupt type information. When a slave node experiences an interrupt, it can initiate an interrupt to indicate the location and type of the interrupt to the master node. "Slave node interrupt" can be understood as: the slave node itself has experienced an interrupt; or, an interrupt related to the slave node has occurred, for example, if the slave node is not a terminal slave node, and an interrupt occurs between the slave node and the downlink slave node, this interrupt can be considered a slave node-related interrupt; or, an interrupt affecting the slave node has occurred, for example, an interrupt in the communication bus of an audio / video system, which may affect the stability of the audio / video system, in which case the interrupt is considered to affect the current slave node. Furthermore, the interrupt type includes any of the following: cable fault, bus error, master node-related interrupt, interrupt configuration register interrupt, or mailbox interrupt. The eighth byte carries verification information, which is used to verify the information carried by the sixth and seventh bytes.

[0164] It should be noted that S405 can be executed synchronously with S403, or it can be executed after S403, or it can be executed before S403.

[0165] It should also be noted that slave node 1 can be a slave node directly connected to the master node, or slave node 1 and the master node can be connected to one or more slave nodes in sequence. Slave node 3 can be a terminal slave node, meaning that the downlink of slave node 3 does not connect to any other slave node; or slave node 3 can be an intermediate slave node, meaning that the downlink of slave node 3 is connected to at least one other slave node. When slave node 3 is an intermediate slave node, slave node 3 will send discovery frame 2 to the slave node on its downlink. In addition, slave node 1 and slave node 2 may be connected to one or more slave nodes in sequence, and slave node 2 and slave node 3 may also be connected to one or more slave nodes in sequence.

[0166] Among them, the last slave node is the last slave node in the daisy chain of the audio and video system. This slave node has no downlink, or the downlink of this slave node has no other slave nodes.

[0167] In practice, after slave node 1 sets identifier 1 to its own identifier, it can repeatedly send discovery frame 2 to slave node 2. When slave node 2 receives multiple discovery frames 2, it can also forward these multiple discovery frames 2 to slave node 3.

[0168] S406, the master node sends a discovery frame 3 to the slave node 1. The discovery frame 3 carries synchronization information 2 and indication information 2 indicating that the discovery frame 3 is a valid frame.

[0169] In some implementations, discovery frame 3 has the same structure and carries similar information content as discovery frame 1. The difference is that discovery frame 3 carries identifier 2.

[0170] S407, Node 1 determines that identifier 2 is different from its own identifier.

[0171] S408, Node 1 sends discovery frame 3 to Node 2.

[0172] S409, set identifier 2 from node 2 to its own identifier.

[0173] S410, Node 2 sends a discovery frame 4 carrying synchronization information 2 to Node 3.

[0174] In some implementations, discovery frame 4 has the same structure and carries similar information content as discovery frame 2. The method of obtaining and sending discovery frame 4 from node 2 is the same as the method of obtaining and sending discovery frame 2 from node 1. For details, please refer to the description in S403, which will not be repeated here.

[0175] S411, Node 2 sends uplink frame 2 to Node 1.

[0176] The information indicated by uplink frame 2 is similar to that indicated by uplink frame 1. The method by which slave node 2 determines and sends uplink frame 2 is similar to the method by which slave node 1 sends uplink frame 1. For details, please refer to the description in S405, which will not be repeated here.

[0177] S412, send uplink frame 2 from node 1 to the master node.

[0178] For example, after receiving uplink frame 2, the master node completes the discovery of slave node 2.

[0179] S413, the master node sends a discovery frame 5 to the slave node 1. The discovery frame 5 carries synchronization information 3 and indication information 3 indicating that the discovery frame 5 is a valid frame.

[0180] Frame 5 was found to also carry identifier 3.

[0181] S414, determine from node 1 that identifier 3 is different from its own identifier.

[0182] S415, Node 1 sends discovery frame 5 to Node 2.

[0183] S416, determine from node 2 that identifier 3 is different from its own identifier.

[0184] For example, if node 2 receives discovery frame 5 and determines that identifier 3 is different from its own identifier, then it confirms that the master node has discovered node 2, and the state of node 2 changes from undiscovered to discovered.

[0185] S417, Node 2 sends discovery frame 5 to Node 3.

[0186] S418, set identifier 3 from node 3 to its own identifier.

[0187] S419, Node 3 sends uplink frame 3 to Node 2.

[0188] S420, Node 2 sends uplink frame 3 to Node 1.

[0189] S421, Node 1 sends uplink frame 3 to the master node.

[0190] For example, after receiving uplink frame 3, the master node completes the discovery of slave node 3.

[0191] For more detailed implementation methods of S413 to S421, please refer to the descriptions in S401 to S412, which will not be repeated here.

[0192] Based on the communication method in Method 400, the processing logic of a slave node after receiving a discovery frame can be summarized in the flowchart shown in Figure 9. Specifically, the processing flow of a slave node after receiving a discovery frame includes:

[0193] S501, determine whether the frame validity field of the discovered frame indicates "valid".

[0194] When the frame validity field indicates "valid", it means that the discovery frame is a valid frame, that is, the discovery frame can be used for discovery from the node.

[0195] Specifically, if the frame validity field of the discovery frame received by the current slave node indicates "valid", S502 is executed; otherwise, the current slave node forwards the discovery frame directly to the slave node of the downlink; when a response frame associated with the discovery frame is received from the slave node of the downlink, the current slave node forwards the response frame directly to the slave node or master node of the uplink.

[0196] S502, whether the current slave node has been discovered.

[0197] If the current slave node has been discovered (i.e., has been assigned an identifier), execute S503; otherwise, execute S504.

[0198] S503, check if the identifier in the detection frame is the same as the identifier of the current slave node.

[0199] If the identifier in the discovery frame matches the identifier of the current slave node, the current slave node sets the frame validity field in the discovery frame to "invalid" to obtain a new discovery frame. If the current slave node is not the final slave node, it forwards the new discovery frame to the slave nodes of the downlink. Furthermore, the current slave node sends a response frame associated with the new discovery frame to the uplink slave node or master node to indicate to the master node that the identifier in the new discovery frame has been assigned.

[0200] If the identifier in the discovery frame is different from the identifier of the current slave node, and the current slave node is not the end slave node, the current slave node forwards the discovery frame to the downlink slave node; when it receives a response frame associated with the discovery frame sent by the downlink slave node, the current slave node forwards the response frame directly to the uplink slave node or master node.

[0201] S504, check if the identifier in the frame is within the set of valid slave node identifiers.

[0202] If the identifier in the discovery frame is within the set of valid slave node identifiers, the current slave node sets the identifier in the discovery frame to its own identifier, and at this time, the slave node's state changes from undiscovered to discovered. Further, if the current slave node is not the final slave node, the current slave node sets the frame validity field in the discovery frame to "invalid" to obtain a new discovery frame, and forwards the new discovery frame to the downlink slave nodes. Furthermore, the current slave node sends a response frame associated with this discovery frame to the uplink slave node or master node to indicate to the master node that the identifier in the discovery frame has been assigned. It should be understood that the response frame associated with the discovery frame at this time is generated (or initiated) by the current slave node.

[0203] If the identifier in the discovery frame is not in the set of valid slave node identifiers, the current slave node forwards the discovery frame directly to the slave node of the downlink; and there is no uplink action.

[0204] It should be noted that, in this application, setting a field to a certain information can be understood as configuring the value of the field to the numerical value corresponding to that information. For example, setting a valid field to "invalid" can mean: configuring the value of the valid field to the numerical value indicating invalidity; and, for another example, configuring an identifier field to a slave node identifier can mean: configuring the value of the identifier field to the numerical value corresponding to the slave node identifier.

[0205] In some implementations, the master node may stop sending discovery frames once it has discovered all slave nodes in the system. In other implementations, the master node may also send additional discovery frames upon discovering all slave nodes in the system. The identifier field of these additional discovery frames may carry an identifier outside the set of valid slave node identifiers; for example, it may carry any identifier from 100001 to 101000.

[0206] In some implementations, the number of slave nodes in the audio / video system is pre-configured for the master node. For example, if the master node is pre-configured to have N slave nodes in the audio / video system, then during the discovery process, after assigning an identifier to each slave node (e.g., upon receiving a relevant response frame), the master node counts the slave nodes with assigned identifiers. When the count indicates that the number of slave nodes with assigned identifiers is N, the master node can determine that it has completed the discovery of all slave nodes in the audio / video system. In other implementations, after the master node successfully assigns an identifier to the end slave node, it continues to send discovery frames. The identifier carried in this discovery frame is obtained by adding 1 to the identifier assigned to the end slave node. For example, if the identifier of the end slave node is M, then the identifier carried in this discovery frame is M+1. Furthermore, when the end slave node receives the discovery frame, it determines that the identifier carried in the discovery frame is different from its own identifier, and that the end slave node has no downlink, or that the downlink of the end slave node has no slave node. Then, the end slave node sends a specific response frame to the uplink. This specific response frame also includes an identifier field and a frame acknowledgment field. However, unlike the aforementioned uplink frames 1 to 3, this specific response frame indicates that the identifier in the identifier field has not been assigned to any slave node. When the master node receives this specific response frame, it can determine that the discovery of all slave nodes in the audio / video system is complete. In one example, the frame number and frame type of the specific response frame are the same as those of the discovery frame carrying identifier M+1, but the identifier field in the specific response frame carries identifier M, not identifier M+1. In actual implementation, only the end slave node may have the ability to send specific response frames.

[0207] The foregoing embodiments, based on Figures 4 to 10, detail the actions performed by the master node and each slave node during the slave node discovery process, as well as the specific form of the discovery frame. It should be understood that in actual implementation, after the master node sends a discovery frame, it may not receive a response frame for that discovery frame within a certain time period. In this case, the master node can resend the discovery frame. For example, as shown in Figure 10, if the nearest neighbor slave node in the uplink of slave node n has been discovered, or slave node n is the first slave node, then discovery frame n is used to assign an identifier to slave node n. After the master node sends discovery frame n, if the uplink response time has been reached and the number of retransmissions of discovery frame n has not reached the maximum number of retransmissions, the master node retransmits discovery frame n until it receives a response frame n associated with that discovery frame n (i.e., the frame number and frame type of response frame n are the same as those of discovery frame n). After this, the master node can determine that the discovery of slave node n is complete. For example, as shown in Figure 11, after the master node sends discovery frame n, if the uplink response time has been reached and the retransmission count of discovery frame n has reached the maximum retransmission count, the master node stops sending discovery frame n and determines that slave node n has failed to discover. In some implementations, if the master node still has not received a response frame related to discovery frame n after reaching the maximum retransmission count, it can determine that slave node n has failed to discover, and also determine that slave node n-1 and all slave nodes before it have successfully discovered. If the master node determines that slave node n has failed to discover, it can send a prompt message to the master controller indicating that the slave node discovery has failed, so that engineers can inspect the audio and video system and eliminate the fault that caused the slave node discovery failure.

[0208] In some implementations, the transmission frames involved in this application all include a synchronization field and a control field. This transmission frame can be a discovery frame or an uplink frame as described in the preceding embodiments. Specifically, the synchronization field carries synchronization information, and the control field carries information such as frame number, frame type, and slave node identifier. More specifically, the synchronization field can consist of two parts: synchronization sequence 1 and synchronization sequence 2. A non-end slave node can start forwarding synchronization sequence 1 after detecting it. If synchronization sequence 2 is detected, the end slave node should continue forwarding synchronization sequence 2 and the remaining parts of the discovery frame (such as the control field content) after forwarding synchronization sequence 1. If the end slave node does not detect synchronization sequence 2, it stops frame transmission after forwarding synchronization sequence 1.

[0209] In one example, synchronization sequence 1 and synchronization sequence 2 can each be 20 bits. The binary representation of synchronization sequence 1 is 0101 0100 11011001 0011. When the transmission frame is a downlink frame (such as a discovery frame), the binary representation of synchronization sequence 2 is 0101 0101 0101 0101 0101; when the transmission frame is an uplink frame, the binary representation of synchronization sequence 2 is 0110 1001 1010 0110 1001.

[0210] In another example, synchronization sequence 1 is 16 bits and synchronization sequence 2 is 24 bits. The binary representation of synchronization sequence 1 is 0101 0101 0101 0101. When the transmission frame is a downlink frame (such as a discovery frame), the binary representation of synchronization sequence 2 is 0101 0100 1101 1001 0011 0101; when the transmission frame is an uplink frame, the binary representation of synchronization sequence 2 is 0101 0100 1101 1001 0011 1010.

[0211] In another example, synchronization sequence 1 is 26 bits, and synchronization sequence 2 is 14 bits. The binary representation of synchronization sequence 1 is 01 0101 0101 0101 0101 0101 0101. When the transmission frame is a downlink frame (such as a discovery frame), synchronization sequence 2 is k28.5+0101, and its binary representation is 00 1111 1010 0101; when the transmission frame is an uplink frame, synchronization sequence 2 is k28.5+1010, and its binary representation is 00 1111 1010 1010. In this case, when a slave node detects the presence of k28.5, it should be considered that synchronization sequence 2 has been detected. Here, k28.5 is an 8B / 10B encoded codeword, which satisfies the following Table 1.

[0212] Table 1

[0213] Figure 12 shows another schematic flowchart of the communication method provided in this application embodiment. This method 1100 can be executed by the audio / video system 100 shown in Figure 1, or it can also be applied to the audio / video system shown in Figure 2. This method 1100 can be executed by a first slave node. The first slave node can be a slave node directly connected to the master node, or it can be any slave node in a daisy-chain network. The method 1100 includes:

[0214] S1110, Receive a first discovery frame, the first discovery frame carries a first identifier and first indication information; wherein, the first indication information is used to indicate the validity of the first discovery frame.

[0215] For example, the first indication information indicating the validity of the first discovery frame includes: the first indication information indicating that the first discovery frame is a valid frame, or the first indication information indicating that the first discovery frame is an invalid frame. Specifically, the first discovery frame also carries an identifier. The first indication information indicating that the first discovery frame is a valid frame can be understood as: the first discovery frame is used for slave node discovery, that is, the first identifier is an identifier that can be assigned to a slave node that has not been assigned an identifier as a slave node identifier. The first indication information indicating that the first discovery frame is an invalid frame can be understood as: the first discovery frame does not carry an identifier that can be assigned to a slave node identifier, for example, the first identifier has already been assigned to a slave node, or the first identifier is not an identifier that can be assigned to a slave node, for example, the first identifier does not belong to the set of valid slave node identifiers.

[0216] S1120, when the first identifier belongs to the set of valid slave node identifiers and the first indication information indicates that the first discovery frame is a valid frame, a first uplink frame is sent. The first uplink frame includes a second identifier, and the second identifier belongs to the set of valid slave node identifiers. The set of valid slave node identifiers includes at least one slave node identifier.

[0217] For example, the first discovery frame can be any one of discovery frame 1, discovery frame 3, or discovery frame 5 in method 400, and correspondingly, the first indication information can be one of indication information 1, indication information 2, or indication information 3 in method 400. Alternatively, the first discovery frame can also be other discovery frames.

[0218] In some implementations, the method further includes: when the first slave node receives the first discovery frame while in an undiscovered state, sending a second discovery frame, the second discovery frame including second indication information indicating that the second discovery frame is an invalid frame. Furthermore, the first discovery frame and the second discovery frame have the same frame number and frame type.

[0219] In some implementations, the method further includes: setting a first identifier as the identifier of a first slave node. Furthermore, a first uplink frame is determined, wherein the frame number and frame type of the first uplink frame are the same as those of the first discovery frame, and the second identifier is the same as the first identifier.

[0220] For example, if the first slave node is slave node 1 in method 400, the first discovery frame is discovery frame 1 in method 400, then the second discovery frame can be discovery frame 2 in method 400, the second indication information can be indication information a, and the first uplink frame can be uplink frame 1 in method 400.

[0221] In some implementations, the method further includes sending a first discovery frame when the first slave node is in a discovered state and the first identifier is different from the identifier of the first slave node. For example, the first slave node is slave node 1 in method 400, and the first discovery frame is discovery frame 3 in method 400. In this implementation, the method further includes receiving a first uplink frame. That is, the slave node that initiated the first uplink frame is not the first slave node.

[0222] In some implementations, the method further includes: when the first slave node is in a discovered state and the first identifier is the same as the identifier of the first slave node, sending a third discovery frame, the third discovery frame including third indication information, the third indication information indicating that the third discovery frame is an invalid frame. For example, before sending the third discovery frame, the third discovery frame can be determined based on the first discovery frame; for example, the first indication information in the first discovery frame can be modified to the third indication information to obtain the third discovery frame. The specific implementation for determining the third discovery frame when the first indication information and the third indication information are carried by the frame validity field can be referred to the description in S503, and will not be repeated here.

[0223] In some implementations, when the first slave node is in a discovered state, is an end slave node, and its identifier is different from the first identifier, the second identifier is the identifier of the first slave node. In this implementation, the first uplink frame indicates that the first identifier has not been assigned to a slave node. In this case, the first uplink frame can be a specific response frame from the aforementioned embodiments.

[0224] In some implementations, the first discovery frame includes a control field and a synchronization field. The synchronization field is used for clock synchronization, and the control field includes a first identifier and first indication information.

[0225] In some implementations, the first uplink frame further includes fourth indication information, which indicates whether the slave node corresponding to the second identifier has correctly received the control field of the first discovery frame. For example, the fourth indication information may be the information carried by the frame confirmation field in the aforementioned embodiments.

[0226] In some implementations, the first discovery frame further includes fifth indication information, which indicates the uplink frame response time. The uplink frame response time is used to calculate the time when the uplink frame was initiated. For example, the fourth indication information may be the information carried by the uplink frame response time field in the aforementioned embodiments.

[0227] In some implementations, the synchronization domain includes a first synchronization sequence and a second synchronization sequence. The method further includes: upon detecting the first synchronization sequence, starting to transmit a first downlink frame, the first downlink frame being associated with a first discovery frame. For example, if the first slave node is slave node 1 and the first discovery frame is discovery frame 1, then the first downlink frame is discovery frame 2; or, the first discovery frame is discovery frame 3 received from the master node, and the first downlink frame is discovery frame 3 transmitted to slave node 2. The first synchronization sequence can be synchronization sequence 1 in the aforementioned embodiments, and the second synchronization sequence can be synchronization sequence 2 in the aforementioned embodiments.

[0228] The communication method provided in this application embodiment enables slave nodes to quickly determine whether the identifier carried in the discovery frame can be assigned to a slave node without an identifier as a slave node identifier through the first indication information. In other words, the slave node can determine whether the first identifier can be assigned to a slave node without an identifier based at least on the field carrying the first indication information and / or the field carrying the first identifier. This helps to reduce the processing complexity of slave nodes in the node discovery process, saves the time required for slave nodes to process discovery frames, and thus improves the slave node discovery speed to achieve rapid slave node discovery.

[0229] Figure 13 shows another schematic flowchart of the communication method provided in an embodiment of this application. This method 1200 can be executed by the audio / video system 100 shown in Figure 1, or it can also be applied to the audio / video system shown in Figure 2. This method 1200 can be executed by the master node, and includes:

[0230] S1210, a first discovery frame is sent, the first discovery frame carries a first identifier and first indication information; wherein, the first indication information is used to indicate the validity of the first discovery frame, the first identifier belongs to the set of valid slave node identifiers, and the set of valid slave node identifiers includes at least one slave node identifier.

[0231] S1220, if no first response frame associated with the first discovery frame is received within the first time period, the first discovery frame is sent again.

[0232] In some implementations, the method further includes: recording the number of times the first discovery frame is sent when sending the first discovery frame; S1220 can be refined to: if the first response frame is not received within a first duration and the number of times the first discovery frame is sent is less than a threshold, then the first discovery frame is sent again. For example, the threshold can be the maximum number of retransmissions corresponding to the portion of Figure 10 or Figure 11, and the first duration can be the uplink response duration corresponding to the portion of Figure 10 or Figure 11.

[0233] In some implementations, the method further includes: recording the number of times the first discovery frame is sent when sending the first discovery frame; and when no first response frame is received within a first time period, and the number of times the first discovery frame is sent is not less than a threshold, indicating a first message that the discovery of the slave node has failed. For example, the first message may be sent to the master controller, so that the master controller can display the first message through a prompting device (such as a vehicle display screen, speaker, or other prompting device).

[0234] In some implementations, the method further includes: stopping the transmission of discovery frames once identifiers have been assigned to all slave nodes in the system, including the master node and the first slave node. The method for determining how the master node assigns identifiers to all slave nodes can be found in the description of the foregoing embodiments, and will not be repeated here.

[0235] The communication method provided in this application, when the master node sends a discovery frame but does not receive any related response information about the discovery frame, resends the discovery frame, which helps to improve the robustness of the audio and video system in the process of discovering slave nodes and helps to achieve rapid discovery of slave nodes.

[0236] The communication method and the frame structure of the transmission frames involved in the communication process have been described in detail above. In the various embodiments of this application, unless otherwise specified or logically conflicting, the terminology and / or descriptions between the embodiments are consistent and can be referenced mutually. Technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships.

[0237] The methods provided by the embodiments of this application have been described in detail above with reference to Figures 1 to 13. The apparatus provided by the embodiments of this application will now be described in detail below with reference to Figures 14 and 15. It should be understood that the descriptions of the apparatus embodiments correspond to the descriptions of the method embodiments; therefore, any content not described in detail can be found in the above method embodiments, and for the sake of brevity, will not be repeated here.

[0238] Figure 14 shows a schematic block diagram of a communication device 2000 provided in an embodiment of this application. The device 2000 may include units for executing the methods described in the foregoing embodiments. Furthermore, each unit in the device 2000 implements a corresponding process of the above-described method embodiments. The device 2000 includes a transceiver unit 2010, which can be used to implement corresponding data acquisition or transmission / reception functions. The device 2000 also includes a processing unit 2020, which can be used to implement corresponding processing functions.

[0239] Optionally, the device 2000 further includes a storage unit, which can be used to store instructions and / or data. The processing unit 2020 can read the instructions and / or data in the storage unit so that the device can perform the relevant actions in the aforementioned method embodiments.

[0240] It should be understood that the specific process of each unit performing the above-mentioned corresponding steps has been described in detail in the above method embodiments, and will not be repeated here for the sake of brevity.

[0241] It should also be understood that the device 2000 described herein is embodied in the form of a functional unit. The terms “module” or “unit” may refer to application-specific ASICs, electronic circuits, processors (e.g., shared processors, proprietary processors, or group processors) and memory for executing one or more software or firmware programs, integrated logic circuits, and / or other suitable components that support the described functions.

[0242] The apparatus in this embodiment has the function of implementing the corresponding steps in the aforementioned method. The function can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions; for example, the transceiver unit 2010 can be replaced by a transceiver, and other units, such as the processing unit, can be replaced by a processor, used to execute the relevant processing operations in each method embodiment.

[0243] For example, when the device 2000 is used to perform the steps performed by the slave node, the transceiver unit 2010 and the processing unit 2020 can be chips or circuits in the slave node; when the device 2000 is used to perform the steps performed by the master node, the transceiver unit 2010 and the processing unit 2020 can be chips or circuits in the master node.

[0244] In the specific implementation process, the units in the above devices can be fully or partially integrated together, or they can be implemented independently. In one implementation, these units are integrated together and implemented in the form of a system-on-a-chip (SoC).

[0245] Figure 15 is another schematic block diagram of the communication device provided in an embodiment of this application. The device 2100 shown in Figure 15 may include a processor 2110, a transceiver 2120, and a memory 2130. The processor 2110, transceiver 2120, and memory 2130 are connected via internal connection paths. The memory 2130 is used to store instructions, and the processor 2110 is used to execute the instructions stored in the memory 2130 to implement the methods in the above embodiments. Optionally, the memory 2130 may be coupled to the processor 2110 via an interface or integrated with the processor 2110.

[0246] It should be noted that the transceiver 2120 mentioned above may include, but is not limited to, transceiver devices such as input / output interfaces, to realize communication between device 2100 and other devices or communication networks.

[0247] Memory 2130 can be volatile memory and / or non-volatile memory. Non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory can be random access memory (RAM). For example, RAM can be used as an external cache. By way of example and not limitation, RAM includes various forms such as: static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous linked dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM).

[0248] Transceiver 2120 uses transceiver devices, such as but not limited to transceivers, to enable communication between device 2100 and other devices or communication networks to receive / send data / information for implementing the methods in the above embodiments.

[0249] This application also provides an audio-visual system, which includes the device 2000 or device 2100 in the above embodiments.

[0250] This application also provides a vehicle that includes the audio-visual system described in the foregoing embodiments.

[0251] This application also provides a computer program product, which includes computer program code. When the computer program code is run on a computer, it causes the computer to implement the methods described in the above embodiments of this application.

[0252] This application also provides a computer-readable storage medium storing computer instructions that, when executed on a computer, cause the computer to implement the methods described in the above embodiments of this application.

[0253] This application also provides a chip, including circuitry, for performing the methods described in the above embodiments of this application.

[0254] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0255] In the description of the embodiments of this application, unless otherwise stated, " / " means "or", for example, A / B can mean A or B; "and / or" in this document describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. In this application, "at least one" means one or more, and "more" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.

[0256] The use of prefixes such as "first" and "second" in this application embodiment is solely for distinguishing different descriptive objects and does not limit the position, order, priority, quantity, or content of the described objects. The use of ordinal numbers and other prefixes to distinguish descriptive objects in this application embodiment does not constitute a limitation on the described objects. The description of the described objects is found in the claims or the context of the embodiments, and the use of such prefixes should not constitute unnecessary restrictions.

[0257] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0258] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions between the various embodiments are consistent and can be referenced by each other. Technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

[0259] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0260] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0261] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A communication method, characterized in that, Applied to the first slave node, the method includes: Receive a first discovery frame, the first discovery frame carrying a first identifier and first indication information; The first indication information is used to indicate the validity of the first discovery frame; When the first identifier belongs to the set of valid slave node identifiers, and the first indication information indicates that the first discovery frame is a valid frame, Send a first uplink frame, the first uplink frame including a second identifier, the second identifier belonging to the set of valid slave node identifiers; The set of valid slave node identifiers includes at least one slave node identifier.

2. The method according to claim 1, characterized in that, The method further includes: When the first slave node receives the first discovery frame while it is in an undiscovered state, it sends a second discovery frame. The second discovery frame includes second indication information, which indicates that the second discovery frame is an invalid frame.

3. The method according to claim 2, characterized in that, The first discovery frame and the second discovery frame have the same frame number and frame type.

4. The method according to claim 2 or 3, characterized in that, The method further includes: Set the first identifier to the identifier of the first slave node.

5. The method according to claim 1, characterized in that, The method further includes: When the first slave node is in a discovered state and the first identifier is different from the identifier of the first slave node, the first discovery frame is sent.

6. The method according to claim 5, characterized in that, The method further includes: Receive the first uplink frame.

7. The method according to claim 1, characterized in that, The method further includes: When the first slave node is in a discovered state and the first identifier is the same as the identifier of the first slave node, a third discovery frame is sent. The third discovery frame includes third indication information, which indicates that the third discovery frame is an invalid frame.

8. The method according to any one of claims 1 to 7, characterized in that, The second identifier is the same as the first identifier.

9. The method according to claim 1, characterized in that, When the first slave node is in a discovered state, the first slave node is an end slave node, and the identifier of the first slave node is different from the first identifier, the second identifier is the identifier of the first slave node.

10. The method according to claim 9, characterized in that, The first uplink frame indicates that the first identifier has not been assigned to the slave node.

11. The method according to any one of claims 1 to 10, characterized in that, The first discovery frame includes a control field and a synchronization field. The synchronization field is used for clock synchronization, and the control field includes the first identifier and the first indication information.

12. The method according to claim 11, characterized in that, The first uplink frame also includes fourth indication information, which indicates whether the slave node corresponding to the second identifier has correctly received the control field of the first discovery frame.

13. The method according to claim 11 or 12, characterized in that, The synchronization domain includes a first synchronization sequence and a second synchronization sequence, and the method further includes: Upon detection of the first synchronization sequence, transmission of the first downlink frame begins, the first downlink frame being associated with the first discovery frame.

14. The method according to any one of claims 1 to 13, characterized in that, The first discovery frame also includes a fifth indication information, which indicates the uplink frame response time and is used to calculate the time when the uplink frame is initiated.

15. A communication method, characterized in that, Applied to the master node, including: Send a first discovery frame, the first discovery frame carrying a first identifier and first indication information; Wherein, the first indication information is used to indicate the validity of the first discovery frame, and the first identifier belongs to the set of valid slave node identifiers, the set of valid slave node identifiers includes at least one slave node identifier; If no first response frame associated with the first discovery frame is received within the first time period, the first discovery frame is sent again.

16. The method according to claim 15, characterized in that, The method further includes: When sending the first discovery frame, record the number of times the first discovery frame is sent; When no first response frame associated with the first discovery frame is received within the first time period, retransmitting the first discovery frame includes: If the first response frame is not received within the first time period, and the number of times the first discovery frame is sent is less than the number threshold, the first discovery frame is sent again.

17. The method according to claim 15, characterized in that, The method further includes: When sending the first discovery frame, record the number of times the first discovery frame is sent; If the first response frame is not received within the first time period, and the number of times the first discovery frame is sent is not less than the number threshold, a first message is displayed, indicating that the discovery from the node has failed.

18. The method according to any one of claims 15 to 17, characterized in that, The method further includes: Once an identifier has been assigned to all slave nodes in the system, including the master node and the first slave node, stop sending discovery frames.

19. A communication device, characterized in that, Located at the first slave node, the device includes: The transceiver unit receives a first discovery frame, which carries a first identifier and first indication information. The first indication information is used to indicate the validity of the first discovery frame; The transceiver unit is further configured to: when the first identifier belongs to the set of valid slave node identifiers and the first indication information indicates that the first discovery frame is a valid frame, Send a first uplink frame, the first uplink frame including a second identifier, the second identifier belonging to the set of valid slave node identifiers; The set of valid slave node identifiers includes at least one slave node identifier.

20. The apparatus according to claim 19, characterized in that, The transceiver unit is also used for: When the first slave node receives the first discovery frame while it is in an undiscovered state, it sends a second discovery frame. The second discovery frame includes second indication information, which indicates that the second discovery frame is an invalid frame.

21. The apparatus according to claim 20, characterized in that, The first discovery frame and the second discovery frame have the same frame number and frame type.

22. The apparatus according to claim 19 or 20, characterized in that, The device further includes a processing unit for: Set the first identifier to the identifier of the first slave node.

23. The apparatus according to claim 19, characterized in that, The transceiver unit is also used for: When the first slave node is in a discovered state and the first identifier is different from the identifier of the first slave node, the first discovery frame is sent.

24. The apparatus according to claim 23, characterized in that, The transceiver unit is also used for: Receive the first uplink frame.

25. The apparatus according to claim 19, characterized in that, The transceiver unit is also used for: When the first slave node is in a discovered state and the first identifier is the same as the identifier of the first slave node, a third discovery frame is sent. The third discovery frame includes third indication information, which indicates that the third discovery frame is an invalid frame.

26. The apparatus according to any one of claims 19 to 25, characterized in that, The second identifier is the same as the first identifier.

27. The apparatus according to claim 19, characterized in that, When the first slave node is in a discovered state, the first slave node is an end slave node, and the identifier of the first slave node is different from the first identifier, the second identifier is the identifier of the first slave node.

28. The apparatus according to claim 27, characterized in that, The first uplink frame indicates that the first identifier has not been assigned to the slave node.

29. The apparatus according to any one of claims 19 to 28, characterized in that, The first discovery frame includes a control field and a synchronization field. The synchronization field is used for clock synchronization, and the control field includes the first identifier and the first indication information.

30. The apparatus according to claim 29, characterized in that, The first uplink frame also includes fourth indication information, which indicates whether the slave node corresponding to the second identifier has correctly received the control field of the first discovery frame.

31. The apparatus according to claim 29 or 30, characterized in that, The synchronization domain includes a first synchronization sequence and a second synchronization sequence, and the transceiver unit is further configured to: Upon detection of the first synchronization sequence, transmission of the first downlink frame begins, the first downlink frame being associated with the first discovery frame.

32. The apparatus according to any one of claims 19 to 31, characterized in that, The first discovery frame also includes a fifth indication information, which indicates the uplink frame response time and is used to calculate the time when the uplink frame is initiated.

33. A communication device, characterized in that, Located on the master node, the device includes: The transceiver unit is used to send a first discovery frame, which carries a first identifier and first indication information. The first indication information is used to indicate the validity of the first discovery frame, and the first identifier belongs to the set of valid slave node identifiers. The set of valid slave node identifiers includes at least one slave node identifier; The transceiver unit is further configured to: if no first response frame associated with the first discovery frame is received within a first time period, retransmit the first discovery frame.

34. The apparatus according to claim 33, characterized in that, The device further includes a processing unit for: When sending the first discovery frame, record the number of times the first discovery frame is sent; The transceiver unit is used for: If the first response frame is not received within the first time period, and the number of times the first discovery frame is sent is less than the number threshold, the first discovery frame is sent again.

35. The apparatus according to claim 33, characterized in that, The device further includes a processing unit for: When sending the first discovery frame, record the number of times the first discovery frame is sent; If the first response frame is not received within the first time period, and the number of times the first discovery frame is sent is not less than the number threshold, a first message is displayed, indicating that the discovery from the node has failed.

36. The apparatus according to any one of claims 33 to 35, characterized in that, The device further includes a processing unit for: Once an identifier has been assigned to all slave nodes in the system, including the master node and the first slave node, stop sending discovery frames.

37. A communication device, characterized in that, include: Memory, used to store computer programs; A processor for executing a computer program stored in the memory to cause the apparatus to perform the method as described in any one of claims 1 to 14.

38. A communication device, characterized in that, include: Memory, used to store computer programs; A processor for executing a computer program stored in the memory to cause the apparatus to perform the method as described in any one of claims 15 to 18.

39. An audio-visual system, characterized in that, It includes the apparatus as described in any one of claims 19 to 32, and the apparatus as described in any one of claims 33 to 36; or, it includes the apparatus as described in claim 37 and the apparatus as described in claim 38.

40. A vehicle, characterized in that, Including the system as described in claim 39.

41. A computer-readable storage medium, characterized in that, It stores instructions that, when executed by a processor, cause the processor to implement the method as described in any one of claims 1 to 14, or the method as described in any one of claims 15 to 18.

42. A chip, characterized in that, The chip includes circuitry for performing the method as described in any one of claims 1 to 14, or the method as described in any one of claims 15 to 18.

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