Multi-device wireless intercom system and method of implementing the same

Abstract

The application discloses a multi-device wireless intercom system and an implementation method thereof, and relates to the technical field of wireless communication.The system comprises a master device end, which is used for establishing a multipoint-to-multipoint transmission network and coordinating data transmission tasks in the network, and selecting a Bluetooth clock of the master device end as a network clock; after the network is established, the master device end is configured to: when a synchronization message is sent, scheduling all intercom devices in the current network according to the number K of BIS events contained in a BIG event in an equal time interval; through the scheduling, BIS events are allocated to the selected intercom devices for the intercom devices to send voice data on the BIS events; the number of devices capable of simultaneously sending voice data in the network in an equal time interval does not exceed K, and K is a natural number greater than or equal to 2.The multi-device wireless intercom system provided by the application can expand the in-network intercom devices to any number as required.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and in particular to a multi-device wireless intercom system and its implementation method. Background Technology

[0002] Walkie-talkies are commonly used real-time voice communication devices on the market. Multiple walkie-talkies can form a communication group by setting the same frequency and code for group communication, thereby enabling multi-device wireless communication. Traditional walkie-talkies use wireless radio frequency communication and simplex communication mode for voice transmission. Multiple walkie-talkies communicate using a specific frequency on a fixed frequency band. When one walkie-talkie speaks, the others can all listen, but only one side can speak at a time (usually using the PTT button, i.e., Push-To-Talk). Otherwise, communication interference will occur, affecting the efficiency and convenience of voice calls, making it unsuitable for multi-person real-time voice communication in real-world application environments.

[0003] On the other hand, with the popularization of Bluetooth technology and its support for voice, Bluetooth application scenarios are increasing. Bluetooth-based wireless intercom solutions are used to achieve real-time voice communication between Bluetooth devices. Through Bluetooth connection, Bluetooth devices can directly communicate with other paired Bluetooth devices, establishing a temporary voice communication network. Currently, Bluetooth technology has iterated to Bluetooth 5.2, which focuses on LE Audio (also known as LE audio or low-power audio) technology. As a new generation of Bluetooth audio technology standard, LE Audio transmits synchronous audio data on the basis of low-power Bluetooth, breaking the limitation of traditional Bluetooth's inability to transmit synchronous stream data from one point to multiple points, achieving multi-stream transmission, and enhancing the Bluetooth audio experience by combining it with broadcast audio sharing. The LE Audio standard is carried out through two underlying technologies: connection-oriented isochronous stream (CIS) links and broadcast isochronous stream (BIS) links. The CIS link is characterized by point-to-point communication, supporting one-way or two-way audio services from one point to one point; the BIS link is characterized by point-to-multipoint broadcast communication, supporting one-way audio services from one point to multiple points.

[0004] Currently, based on the CIS and BIS technologies provided in the new Bluetooth LE Audio standard, existing technologies offer several multi-user real-time voice communication networks implemented using Bluetooth LE Audio technology. For example, Chinese patent ZL202211480565.5 discloses a real-time intercom method for a distributed ad hoc network based on BIS, including the following steps: Step S100: Each Bluetooth device sends a broadcast packet carrying its own node information and neighbor node information, and receives broadcast packets from neighbor nodes. The broadcast packet includes a node self-information field, a one-hop neighbor node field, and a multi-hop neighbor node field. The node self-information field contains the Bluetooth device address and current Bluetooth clock of the corresponding Bluetooth device; the one-hop neighbor node field contains the Bluetooth device addresses within direct receiving range, and the Bluetooth clock difference between the current Bluetooth device and its neighboring Bluetooth devices; the multi-hop neighbor node field contains the Bluetooth device addresses within indirect receiving range, and the Bluetooth clock difference between the current Bluetooth device and its indirect neighboring devices. The process involves: obtaining the Bluetooth clock difference between Bluetooth devices; acquiring the Bluetooth device addresses and clock information of all nodes in the network; step S200: sorting the Bluetooth devices according to a set rule and selecting the Bluetooth clock of a certain Bluetooth device as the network clock; step S300: each Bluetooth device occupies a different position on the network timeline according to its own sorting information, resulting in a Broadcast-based Connectionless Low Power Transmission (BIS) position arrangement; step S400: each Bluetooth device starts creating a BIS audio stream, sending audio data packets, conducting real-time intercom interaction, and sending a network broadcast packet. The network broadcast packets of each node in the network are sent in idle positions on the network timeline other than the BIS-occupied positions. The network broadcast packet includes a node's own information field, a network clock difference field, and a position arrangement information field. This solution utilizes Bluetooth LE Audio's BIS technology to provide a distributed multi-user real-time voice communication network, improving transmission distance and anti-interference capabilities, exhibiting high flexibility and scalability, and enhancing the communication experience of multi-user wireless intercom systems. For example, Chinese patent ZL202211451813.3 discloses a low-power multi-user real-time voice transmission method based on Bluetooth, including the following steps: a child node sends a non-directional broadcast packet carrying network access application information into the air; after receiving the broadcast packet carrying network access application information from the child node, the central node extracts the network access application information of the child node, assigns a position to the child node on the Bluetooth timeline, and adds the node information to the network information table; the central node sends a broadcast packet carrying network information table data; the child node calculates its own BIG anchor point according to the allocation parameters and event position information in the network information table, creates a BIG event for sending BIS broadcast packets, and calculates the BIG event anchor points of other child nodes, and establishes corresponding BIG SYNC events one by one to receive BIS broadcast packets sent by other child nodes.The above solution provides a centralized multi-user real-time intercom system based on BIG technology in Bluetooth LE Audio. A central node manages the network and uses a dedicated network information table to transmit and configure BIG event information for each node. The BIG event anchor points for each sub-node are separate and non-overlapping, allowing multiple users to speak simultaneously. When multiple users are speaking, the receiver can clearly hear the superposition of their voices. Compared to distributed multi-user real-time voice communication networks, this centralized multi-user real-time intercom system reduces network complexity and maintenance difficulty through centralized network control and resource management by the central node.

[0005] However, both the aforementioned distributed self-organizing network real-time intercom system and the aforementioned centralized multi-person real-time intercom system, when designing a multi-point-to-multi-point data transmission method, aim to ensure that all nodes in the network have the opportunity to transmit data to other nodes simultaneously. Such a system design makes it difficult to significantly expand the number of network nodes. For example, in a more extreme scenario, if 20 people are speaking simultaneously, the system needs to ensure that the audio data of each of the 20 nodes can flow to the other 19 nodes. Existing multi-person real-time intercom systems struggle to support such an audio transmission network, resulting in low networking efficiency and significant difficulties in transmission control and resource scheduling.

[0006] In conclusion, how to provide a multi-person real-time intercom system with unlimited expansion of the number of devices is a technical problem that urgently needs to be solved. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a multi-device wireless intercom system and its implementation method. The multi-device wireless intercom system provided by this invention utilizes the data transmission characteristics of multi-point to multi-point wireless audio communication systems. It schedules and limits the number of intercom devices simultaneously transmitting voice data in the network based on the number K of broadcast isochronous stream BIS events contained in the broadcast isochronous group (BIG) event, rather than limiting the number of node devices accessing the network. This effectively solves the problem of limited device expansion in existing multi-device wireless intercom systems. The multi-device wireless intercom system provided by this invention can expand the number of intercom devices connected to the network to any number as needed.

[0008] To achieve the above objectives, the present invention provides the following technical solution: A multi-device wireless intercom system includes multiple intercom devices with Bluetooth modules, wherein the Bluetooth modules support Bluetooth Low Energy Audio (LE Audio) transmission, wherein one of the multiple intercom devices is designated as the master device, the master device is used to establish a multi-point to multi-point transmission network and coordinate data transmission tasks in the network, and select the Bluetooth clock of the master device as the network clock. After establishing a multi-point to multi-point transmission network, the master device is configured to coordinate data transmission tasks in the network as follows: when sending a synchronization message, all intercom devices in the current network are scheduled according to the number K of broadcast isochronous stream BIS events contained in the broadcast isochronous group BIG event in an isochronous interval (ISO interval); through the scheduling, BIS events are allocated to selected intercom devices so that the intercom device can send its own voice data on the allocated BIS events. The number of intercom devices that can send voice data simultaneously in an ISO interval does not exceed K, where K is a natural number greater than or equal to 2.

[0009] Furthermore, the first intercom device in the system is configured as the master device. The master device is configured to establish a multi-point to multi-point transmission network in the following ways: establish its own low-power Bluetooth broadcast and send broadcast data packets to initiate network formation, wherein the broadcast data packets broadcast the features it supports, including information indicating that the network supports multi-point to multi-point transmission; and when other intercom devices apply to join the aforementioned network by scanning the broadcast, an idle network ID is assigned to the intercom device according to the network registration information of the intercom device applying to join, and the new intercom device joins the aforementioned network through the network ID. When a new intercom device joins the network, the broadcast source device is also configured to, when coordinating data transmission tasks in the network, increase the total number of intercom devices in the current network by 1, and reschedule all intercom devices in the network according to the new total number of intercom devices, so that the number of intercom devices that can transmit voice data simultaneously in the network in an ISO interval does not exceed K.

[0010] Furthermore, during the networking process, the other intercom devices are configured to: enable broadcast scanning, scan for broadcasts with the master device broadcast type, and select the network to join; establish a Bluetooth Low Energy (BLE) connection with the selected master device and perform security authentication; after successful security authentication, send network registration information to the master device to register itself and request a network ID; and after obtaining the network ID assigned by the master device, disconnect the Bluetooth Low Energy (BLE) connection with the master device and join the network established by the aforementioned master device according to the BIS joining process.

[0011] Furthermore, the BIG event includes K BIS events and a control subevent. The control subevent is configured and sent by the master device. The control subevent configures the network's device scheduling control information for the aforementioned scheduling. When scheduling all intercom devices in the current network, the master device is configured to: select the corresponding authorized intercom device from all intercom devices in the network through the Control subevent, and configure the corresponding authorized intercom device to transmit data on one of the aforementioned K BIS events.

[0012] Furthermore, the master device is configured to: obtain the number T of intercom devices in the current network; when the number T of intercom devices is greater than the number K of the aforementioned BIS events, configure the intercom devices in the network through the Control subevent, select K intercom devices as authorized intercom devices from all T intercom devices in the network, and allocate idle BIS events to each of the aforementioned authorized intercom devices; one idle BIS event is allocated to one authorized intercom device. When the authorized intercom device has voice data to send, it sends its own voice data on the assigned BIS event; when the authorized intercom device has no voice data to send, it sends an empty packet (NULL) on the assigned BIS event.

[0013] Furthermore, when scheduling all intercom devices in the current network, the master device is also configured to: monitor the data transmission information of each authorized intercom device in the network; when an authorized intercom device is detected sending a NULL packet, reclaim the time slot of the BIS event occupied by that authorized intercom device, and remove the intercom device whose BIS event has been reclaimed from the list of authorized intercom devices; and, Based on the recovered BIS events, configure other intercom devices in the network through the Control subevent, select new authorized intercom devices from the other intercom devices in the network, and allocate idle BIS events to each of the aforementioned new authorized intercom devices.

[0014] Furthermore, when scheduling devices through the Control Subevent, a Working_list queue, an Idle_list queue, and a Free_list queue are set up to store authorized intercom device information, unauthorized intercom device information, and idle BIS event information, respectively. The content of the CTRL packet of the Control Subevent is determined based on the information in the aforementioned Free_list queue. When the aforementioned Free_list queue is empty, keep the content of the CTRL packet of the Control Subevent unchanged, and wait to enter the next isochronous interval; When the aforementioned Free_list queue is not empty, select an intercom device from the unauthorized intercom devices in the Idle_list queue as a new authorized intercom device, assign an idle BIS event from the Free_list queue to the new authorized intercom device, update the information in the Working_list queue according to the new authorized intercom device, and then modify the content of the CTRL packet of the ControlSubevent control data packet to reconfigure the device scheduling control information so that these newly authorized intercom devices can obtain data transmission rights in the next ISO interval.

[0015] Furthermore, when a walkie-talkie device that has joined the network needs to leave the network, the walkie-talkie device is configured to send a preset termination data packet on the assigned BIS event after it is selected as an authorized walkie-talkie device. When the master device receives the aforementioned termination data packet, it obtains the information of the intercom device that sent the termination data packet, removes the intercom device from the network, reduces the total number of intercom devices in the current network by 1, and then reschedules all intercom devices in the network according to the new total number of intercom devices.

[0016] Furthermore, the master device is also configured to: monitor BIS events in the network; when a signal on a BIS event cannot be correctly parsed within a continuous preset number of equal time intervals (ISO intervals), determine that the corresponding intercom device has left the network, remove the left intercom device from the network, reduce the total number of intercom devices in the current network by 1, and then reschedule all intercom devices in the network according to the new total number of intercom devices.

[0017] Furthermore, the intercom device is one or more of the following: Bluetooth headset, helmet-mounted intercom headset, and handheld intercom device; The intercom device also includes a voice acquisition module, a codec module, a voice processing module, and a voice playback module; When the intercom device needs to send voice data, it acts as a broadcast source device. At this time, the voice acquisition module collects the raw voice data, the encoding and decoding module encodes the raw voice data to obtain an encoded voice data file, and then the Bluetooth module broadcasts the encoded voice data file to itself on the BIS event assigned to it. When the intercom device is used as a broadcast receiver to listen to the broadcast, it scans the broadcast via the Bluetooth module to obtain encoded voice data files broadcast by multiple broadcast source devices. The encoding / decoding module decodes the obtained encoded voice data files to obtain multiple decoded voice data files. The voice processing module mixes the multiple decoded voice data files to obtain mixed audio, and then plays the aforementioned mixed audio through the voice playback module.

[0018] The present invention also provides a method for implementing a multi-device wireless intercom system, the system comprising multiple intercom devices having Bluetooth modules, the Bluetooth modules supporting Bluetooth Low Energy Audio (LE Audio) transmission, comprising the following steps: Configure the main device; The network is established by initiating networking through the master device to build a multi-point to multi-point transmission network, and the Bluetooth clock of the master device is selected as the network clock. After establishing a multi-point to multi-point transmission network, the master device coordinates the data transmission tasks within the network. When sending a synchronization message, the master device schedules all intercom devices in the current network based on the number K of broadcast isochronous stream BIS events contained in the broadcast isochronous group BIG events within an isochronous interval (ISO interval). Through this scheduling, BIS events are allocated to selected intercom devices so that the devices can transmit their own voice data on the allocated BIS events. The number of intercom devices that can simultaneously transmit voice data in an ISO interval does not exceed K, where K is a natural number greater than or equal to 2.

[0019] Compared with existing technologies, this invention, by adopting the above technical solution, has the following advantages and positive effects: The multi-device wireless intercom system provided by this invention utilizes the data transmission characteristics of multi-point to multi-point wireless audio communication systems. It schedules and limits the number of intercom devices simultaneously transmitting voice data in the network based on the number K of broadcast isochronous stream BIS events contained in the broadcast isochronous group (BIG) event, rather than limiting the number of node devices accessing the network. This effectively solves the problem of limited device expansion in existing multi-device wireless intercom systems. The multi-device wireless intercom system provided by this invention can expand the number of intercom devices connected to the network to any number as needed. Attached Figure Description

[0020] Figure 1This is a packet timing diagram for BIS provided in the prior art.

[0021] Figure 2 This invention provides an information processing diagram for building a network on the master device side.

[0022] Figure 3 This invention provides a diagram illustrating the information processing of other intercom devices during network setup.

[0023] Figure 4 The present invention provides a logical flowchart of the data transmission task in the master device coordinating the network.

[0024] Figure 5 This is a timing diagram of data packets for a device to actively leave the network, as provided by the present invention.

[0025] Figure 6 This invention provides a timing diagram of data packets when a device passively exits the network.

[0026] Figure 7 The timing diagram of data packets for data transmission tasks in the network coordinated by the master device when the number of BIS events K=3 is provided by the present invention.

[0027] Figure 8 A flowchart illustrating the implementation method of the multi-device wireless intercom system provided by the present invention. Detailed Implementation

[0028] The multi-device wireless intercom system and its implementation method disclosed in this invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that technologies (including methods and apparatuses) known to those skilled in the art may not be discussed in detail, but where appropriate, the aforementioned known technologies are considered part of the specification. Furthermore, other examples of exemplary embodiments may have different values. The structures, proportions, sizes, etc., depicted in the accompanying drawings are only used to complement the content disclosed in the specification, for those skilled in the art to understand and read, and are not intended to limit the conditions under which the invention can be implemented. In the description of the embodiments of this application, " / " means "or," and "and / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" indicates: A and B exist alone, B exists alone, and A and B exist simultaneously. In the description of the embodiments of this application, "multiple" refers to two or more, and "multi-level" refers to two or more levels.

[0029] To facilitate understanding, the following is a brief description of the relevant configuration information of the Broadcast Isochronous Stream (BIS) in the LE Audio Bluetooth specification.

[0030] According to the BIS protocol in the current LE Audio Bluetooth specification, the broadcast source device sends synchronization messages in the channel in the form of a broadcast. Broadcast receivers connected to the same channel receive synchronization messages by listening to the broadcast. That is, the broadcast source device acts as the sender of the broadcast signal, and one or more broadcast receivers act as the receivers of the broadcast signal. BIG events occur within each equal-time interval (ISO Interval). A BIG can contain multiple BIS events, and a BIG event can include multiple BIS events, such as... Figure 1 The example demonstrates setting up two BIS events, namely BIS0 Event and BIS1 Event. Each BIS event sets the number of sub-events (NSE) of its sub-event to 2, meaning each event has 2 BIS sub-events. Each BIS event is separated by BIS Spacing (in the diagram, BIS Spacing is greater than sub_interval, and the BIS events are arranged sequentially). Functionally, according to the Bluetooth specification, each BIS can contain different audio streams.

[0031] See also Figure 1 As shown, the BIG event also includes an optional Control Subevent. The Control Subevent differs from the BIS event; it primarily updates the BIG's configuration information and can be used to provide control information to each receiver acceptor, such as the Bluetooth channel map and other control information needed in broadcasting. The Control Subevent does not need to be included in every BIG event and is not counted in the subevent count (NSE); it is a completely independent subevent. According to the current BIS protocol, each BIS header of a BIS subevent within a BIG event containing a Control Subevent must set the Control Subevent Transmission Flag (CSTF) to 1 to indicate the presence of a Control Subevent in that BIG event. See also... Figure 1As can be seen, BIG Event2 contains a Control Subevent, which corresponds to a transmission (Tx). The Control Subevent is transmitted after the final Subevent of the last BIS. The anchor point (or starting point) of each BIS event on the timeline is fixed; similarly, the anchor point of the Control Subevent is also fixed and can be obtained through the BIG Control Offset parameter (which represents the time from the BIG anchor point containing the control subevent to the start of the control subevent). All data carried by the subevents (se) in all BIS events is transmitted from the broadcast source device. Data on the BIS link can only be broadcast unidirectionally from one broadcast source device to multiple broadcast receiver devices in a one-to-many manner. Example

[0032] Research on multi-person real-time intercom systems reveals the following characteristics of their communication networks: 1) Any speaker's speech can be received and heard by other devices in the group via wireless communication. 2) In most cases, only one person initiates the conversation; when multiple people speak simultaneously, people will politely or habitually give priority to one person (courtesy avoidance), granting that person the right to speak. 3) Based on the above two points, in such a communication network, in most cases, audio data is transmitted from one node device to all other node devices for a given period of time. 4) During certain special periods—usually short periods—two or more node devices may have audio data flowing to other node devices. 5) Based on the courtesy avoidance in characteristic 2), the communication network generally tends to evolve towards characteristic 3), i.e., only audio data is transmitted from one node device to all other node devices for a given period of time.

[0033] Based on the aforementioned characteristics of this type of communication network, the characteristics of data transmission in this type of communication network can be obtained as follows: audio data flows from one node device to all other node devices; in most cases, only one node device in the network has data flowing to all other node devices; in certain short periods of time, there may be two or more node devices with audio data flowing to all other node devices, these node devices are the node devices that are simultaneously sending voice, and the maximum value of the number N of node devices that are simultaneously sending voice will not exceed the total number of node devices T in the current communication network; the communication network will tend to the data transmission mode in most of the aforementioned cases, that is, only one node device has data flowing to all other node devices.

[0034] In other words, for a multi-person real-time intercom system, regardless of the total number of nodes T in the current communication network (e.g., 10, 20, 50, or 80), the number of nodes N simultaneously transmitting voice will not be too large, and will tend to equal 1. This invention utilizes these characteristics of such communication networks to configure data transmission for node devices in a multi-person real-time intercom system, thereby solving the problem of limited device expansion in existing multi-person real-time intercom systems.

[0035] Specifically, the present invention provides a multi-device wireless intercom system, the system including multiple intercom devices with Bluetooth modules, the Bluetooth modules supporting Bluetooth Low Energy Audio (LE Audio) transmission.

[0036] One of the multiple intercom devices is designated as the master device. The master device is used to establish a multi-point-to-multi-point transmission network and coordinate data transmission tasks within the network. The number of intercom devices connected to the network is unlimited, and the Bluetooth clock of the master device is selected as the network clock.

[0037] Preferably, the first intercom device in the system is configured as the master device. See also Figure 2 As shown, the master device is configured to establish a multi-point to multi-point transmission network in the following manner: establishing its own low-power Bluetooth broadcast and sending broadcast data packets to initiate network formation, wherein the broadcast data packets broadcast the features it supports, including information indicating that the network supports multi-point to multi-point transmission; and, when other intercom devices apply to join the aforementioned network by scanning the broadcast, allocating an idle network ID to the intercom device according to the network registration information of the intercom device applying to join, and the new intercom device joins the aforementioned network through the network ID.

[0038] After a new intercom device joins the network, when coordinating data transmission tasks in the network, the master device is also configured to: increase the total number of intercom devices in the current network by 1, and reschedule all intercom devices in the network according to the new total number of intercom devices, so that the number of intercom devices that can transmit voice data simultaneously in the network in an ISO interval does not exceed K.

[0039] During the network setup process, see Figure 3As shown, the other intercom devices are configured to perform the following steps: initiate broadcast scanning, scan for broadcasts with the master device's broadcast type, and select the network to join; establish a Bluetooth Low Energy (BLE) connection with the selected master device and perform security authentication; after successful security authentication, send network registration information to the master device to register itself and request a network ID; and after obtaining the network ID assigned by the master device, disconnect the BLE connection with the master device and join the network established by the master device according to the BIS joining process. If the aforementioned security authentication fails, the intercom device can return to the aforementioned scanning steps and rescan for surrounding devices.

[0040] After establishing a multi-point to multi-point transmission network, the master device is configured to coordinate data transmission tasks in the network as follows: when sending a synchronization message, all intercom devices in the current network are scheduled according to the number K of broadcast isochronous stream BIS events contained in the broadcast isochronous group BIG event in an isochronous interval (ISO interval); through the scheduling, BIS events are allocated to selected intercom devices so that the intercom device can send its own voice data on the allocated BIS events. The number of intercom devices that can send voice data simultaneously in an ISO interval does not exceed K, where K is a natural number greater than or equal to 2.

[0041] Intercom devices that are not currently selected (and have not obtained data transmission permissions) can wait for an idle BIS event to become available, at which point the aforementioned master device will allocate an idle BIS event for them, allowing them to transmit their voice data. In this way, by scheduling and limiting the number of intercom devices transmitting voice data simultaneously in the network using the number K of BIS events within an ISO interval, the maximum number of intercom devices capable of transmitting simultaneously in the network will not exceed K, without needing to limit the number of node devices accessing the network.

[0042] In this embodiment, the master device can configure the number K of BIS events contained in a BIG event within an ISO interval. For example, when the number K of BIS events is configured to 5, that is, K=5, it means that a BIG event contains 5 BIS events within an ISO interval. In this case, the network can allow a maximum of 5 intercom devices to send voice data simultaneously within an ISO interval, meaning that the number of intercom devices that can send voice data simultaneously does not exceed 5.

[0043] In this embodiment, the value of the number K of BIS events included in the BIG event can be set within a reasonably small range to meet actual communication needs. For ease of description, let the number of intercom devices in the current network be T, and the number of node devices in the network that simultaneously transmit voice be N. The possible values ​​of N, T, and K in the network are described in detail below, where N, T, and K are all natural numbers.

[0044] Based on the characteristics of this type of communication network described above, it is known that in most cases, the number N of nodes simultaneously transmitting voice in the network is equal to 1. Only in a few periods will the number N of nodes simultaneously transmitting voice in the network be 2 or higher, and N will not be too large, while N will tend to be equal to 1. Therefore, regardless of the value of T, we can set the number K of the aforementioned BIS events within a reasonably small range—as an example rather than a limitation, configuring the value of K to 3-5 can meet the actual needs. Moreover, in a multi-person intercom system, if 6 or more people are allowed to speak simultaneously, the result will be that the listeners in the intercom system cannot hear each person speaking. Therefore, K should also be set within a reasonably small range. Using this invention, the number of intercom devices speaking simultaneously within an equal time interval can be limited by K, instead of limiting the total number of intercom devices in the system.

[0045] Taking K=5 as an example, if the number of intercom devices in the multi-device wireless intercom system is T=20 people, and assuming that all 20 people in the system have a need to speak, using the above-mentioned scheme provided by this invention, after the network is established, the master device can select 5 intercom devices to allocate BIS events in the first equal time interval. The 5 intercom devices that have been allocated BIS events obtain data transmission rights, allowing each of these 5 intercom devices to send data to the other 19 intercom devices. When an intercom device finishes sending data, the master device can reclaim the BIS event of that intercom device and then allocate the reclaimed BIS event to other intercom devices that have a need to speak. After obtaining data transmission rights, the intercom device can send data to the other 19 intercom devices in the next equal time interval using the allocated BIS event. In this way, it is ensured that the number of intercom devices simultaneously sending voice data in one equal time interval does not exceed 5, and each intercom device has the opportunity to be allocated a BIS event to send its own voice data. Compared to traditional solutions where data from 20 intercom devices can flow to the other 19, the multi-device wireless intercom system provided in this embodiment is easier to implement and maintain, while offering better communication reliability and robustness. Furthermore, the number of intercom devices in this multi-device wireless intercom system is unlimited, allowing for expansion to any number of devices.

[0046] In specific implementation, the BIG event is configured to include K BIS events and a control sub-event, wherein the control sub-event is used to configure the control information required in the BIS broadcast.

[0047] In this embodiment, the master device configures and sends a Control subevent, which configures network device scheduling control information for the aforementioned scheduling. When scheduling all intercom devices in the current network, the master device is configured to: select a corresponding authorized intercom device from all intercom devices in the network via the Control subevent, and configure that authorized intercom device to transmit data on one of the aforementioned K BIS events.

[0048] Furthermore, the master device is configured to select authorized intercom devices and allocate BIS events in the following manner: obtain the number T of intercom devices in the current network; when the number T of intercom devices is greater than the number K of the aforementioned BIS events, configure the intercom devices in the network through the Control subevent, select K intercom devices as authorized intercom devices from all T intercom devices in the network, regardless of whether the selected intercom devices have data to send; allocate idle BIS events to each of the aforementioned authorized intercom devices, with one idle BIS event being allocated to one authorized intercom device.

[0049] When the authorized intercom device has voice data to send, it sends its own voice data on the assigned BIS event. When the authorized intercom device has no voice data to send, it sends an empty packet (NULL) on the assigned BIS event.

[0050] When scheduling all intercom devices in the current network, the master device can also be configured to: monitor the data transmission information of each authorized intercom device in the network; when an authorized intercom device is detected to send a NULL packet, reclaim the time slot of the BIS event occupied by the authorized intercom device, and remove the intercom device whose BIS event has been reclaimed from the authorized intercom device list; and, based on the reclaimed BIS event, configure other intercom devices in the network through the Control subevent, select new authorized intercom devices from the other intercom devices in the network, and allocate idle BIS events to each of the aforementioned new authorized intercom devices.

[0051] In practical implementation, when scheduling devices via Control Subevent, three queues can be set up: Working_list, Idle_list, and Free_list, to store authorized intercom device information, unauthorized intercom device information, and idle BIS event information, respectively. The content of the CTRL packet in the Control Subevent is then determined based on the information in the Free_list queue. When the Free_list queue is empty, the content of the CTRL packet in the Control Subevent remains unchanged, waiting for the next ISO interval. When the Free_list queue is not empty, an intercom device is selected from the unauthorized devices in the Idle_list queue as a new authorized intercom device. An idle BIS event from the Free_list queue is allocated to the new authorized intercom device, and the information in the Working_list queue is updated based on the new authorized intercom device. Then, the content of the CTRL packet in the Control Subevent is modified to reconfigure the device scheduling control information, enabling these newly authorized intercom devices to obtain data transmission permissions in the next ISO interval.

[0052] As a typical example, the master device schedules the intercom device to send data based on its network access time. See [link to typical device scheduling steps] for details. Figure 4 As shown below.

[0053] S1 initializes K BIS events in the BIG event to idle.

[0054] S2, arrange all T intercom devices in the system in order, with the main device at the first position and the other intercom devices in order of their network access time.

[0055] S3: Designate the top K intercom devices as authorized intercom devices, i.e. data stream sending devices, allocate K idle BIS events to the K authorized intercom devices so that each authorized intercom device can send its own data; put the aforementioned K authorized intercom devices into the Working_list queue, and put the remaining TK unauthorized intercom devices into the Idle_list queue; set the Free_list queue to empty.

[0056] S4. Monitor the data transmission information of the aforementioned K authorized intercom devices. If an authorized intercom device sends a KULL packet, reclaim the corresponding BIS event window and add the reclaimed BIS event to the Free_list queue. At the same time, place the authorized intercom devices that sent KULL packets into the end of the Idle_list queue in order, and delete the authorized intercom devices that sent KULL packets from the Working_list queue. That is, the aforementioned authorized intercom devices become unauthorized intercom devices and enter the Idle_list queue.

[0057] S5, determine whether the aforementioned Free_list queue is empty; if yes, proceed to step S6; if no, proceed to step S7.

[0058] S6: Keep the content of the CTRL packet of the Control Subevent unchanged, and wait for the next ISO interval to begin. When the next ISO interval begins, return to step S4.

[0059] S7: Starting from the head of the Idle_list queue, remove each unauthorized intercom device sequentially until the Free_list queue is full with the corresponding BIS events. Then, allocate the reclaimed BIS events to the removed intercom devices. Next, add these intercom devices to the Working_list queue; these devices then become authorized intercom devices. Modify the CTRL packet of the Control Subevent to schedule these authorized intercom devices in the next ISO interval.

[0060] S8, clear the Free_list queue, making the Free_list queue empty, and wait to enter the next ISO interval.

[0061] Upon entering the next ISO interval, return to step S4. Continue in this manner until data has been transmitted to all intercom devices in the network.

[0062] In this embodiment, when a walkie-talkie device that has joined the network needs to leave the network, the walkie-talkie device is configured to send a preset termination data packet (TERM packet) at the time slot of the allocated BIS event when it is selected as an authorized walkie-talkie device.

[0063] When the master device receives the aforementioned TERM packet, it removes the intercom device that sent the aforementioned TERM packet from the network, reduces the total number of intercom devices in the current network by 1, and then reschedules all intercom devices in the network according to the new total number of intercom devices.

[0064] In other words, this embodiment configures a TERM packet for terminating data packets, see [link / reference]. Figure 5 The data packets marked TERM can be seen to be... Figure 5 Device B sends a TERM packet at B2, meaning that device B actively initiates network withdrawal at B2. Based on this TERM packet, the master device removes the aforementioned device B from the network, reduces the total number of devices T by 1, and then restarts scheduling.

[0065] Besides the aforementioned cases where intercom devices actively initiate network disconnection, in practical applications, there may also be cases where intercom devices are passively disconnected from the network. For example, this could be due to system malfunctions or radio frequency interference causing the device to passively disconnect. In such cases, the master device can be configured to: monitor BIS events in the network; when a signal on a BIS event cannot be correctly parsed within multiple preset ISO intervals, determine that the corresponding intercom device has disconnected from the network, remove the disconnected intercom device from the network, reduce the total number of intercom devices in the current network by 1, and then reschedule all intercom devices in the network according to the new total number of intercom devices. This is an example, not a limitation, such as in... Figure 6 If the signal at the position indicated by the dashed line can no longer be correctly parsed by the master device, and if the signal at this position cannot be correctly parsed within a continuous preset time interval (ISOInterval) – for example, within a preset 3 ISO Intervals – the master device can determine that the corresponding intercom device has been passively disconnected from the network. At this time, the master device will remove the intercom device at this position – for example, the original intercom device B – and reduce the total number of intercom devices T in the network by 1, and then restart the scheduling.

[0066] In this embodiment, the intercom device is one or more of the following: Bluetooth headset, helmet intercom headset, and handheld intercom device.

[0067] The intercom device also includes a voice acquisition module, an encoding / decoding module, a voice processing module, and a voice playback module.

[0068] When the intercom device needs to send voice data, it acts as a broadcast source device. At this time, the voice acquisition module collects the raw voice data, the encoding and decoding module encodes the raw voice data to obtain an encoded voice data file, and then the Bluetooth module broadcasts the encoded voice data file to the assigned BIS event.

[0069] When the intercom device is used as a broadcast receiver to listen to the broadcast, it scans the broadcast via the Bluetooth module to obtain encoded voice data files broadcast by multiple broadcast source devices. The encoding / decoding module decodes the obtained encoded voice data files to obtain multiple decoded voice data files. The voice processing module mixes the multiple decoded voice data files to obtain mixed audio, and then plays the aforementioned mixed audio through the voice playback module.

[0070] The following example uses the configuration of the number of BIS events K to be 3 (i.e., K=3). Figure 7 Describe in detail the data packet timing diagram of the data transmission task in the coordination network on the master device side.

[0071] Imagine a multi-device wireless intercom system comprising six intercom devices, T=6. These devices are designated as Device A, Device B, Device C, Device D, Device E, and Device F. Device A is the first intercom device in the system and is configured as the master device. The master device's Bluetooth clock is used as the network clock, and the master device schedules the data transmission and reception of the other intercom devices. Assume Device A has 3 data packets to send, with the fourth packet being empty (NULL); Device B has 3 data packets to send, with the fourth packet being empty (NULL); Device C has 1 data packet to send, with the second packet being empty (NULL); Device D has 8 data packets to send, with the ninth packet being empty (NULL); and Devices E and F have no data packets to send, with the first packet being empty (NULL).

[0072] Figure 7 This example illustrates packet transmission over six consecutive ISO intervals. Since K=3, there are three BIS events per ISO interval. Furthermore, the Control Subevent (labeled CTRL in the diagram) for the BIG event is reserved for the master device, which configures and sends the Control subevent to maintain consistency in network information such as network clock and frequency hopping sequence. The data transmission tasks are scheduled as follows across the six equal time intervals, in the order of device A, device B, device C, device D, device E, and device F:

[0073] The first equal-time interval (ISO Interval1): Devices A, B, and C are selected as authorized intercom devices, and each is scheduled during idle BIS events. Devices A, B, and C are placed in the Working_list queue, devices D, E, and F are placed in the Idle_list queue, and the Free_list queue is empty. Authorized intercom devices A and B send two data packets each, and authorized intercom device C sends its only data packet, then sends a NULL packet at C2, releasing the subsequent BIS event window and resetting the BIS. The event is added to the Free_list queue, and device C is removed from the Working_list queue. Since the Free_list queue is not empty, device D needs to be removed from the head of the Idle_list queue to fill the corresponding BIS event in the Free_list queue. Then, device D is added to the Working_list queue. At this time, device A, as the master device, selects device D at the head of the queue by configuring CTRL to become an authorized intercom device, enabling it to obtain data transmission permission in the next ISOInterval. The Free_list queue is then set to empty, waiting to enter the next ISOInterval.

[0074] In the second ISO Interval2: Authorized intercom devices A and B each send their remaining data packets and send NULL packets at A4 and B4 respectively to release subsequent BIS event windows. At this time, the corresponding BIS events are added to the Free_list queue, and devices A and B are removed from the Working_list queue. Meanwhile, device D sends D1 and D2 data packets. Then, as above, since the Free_list queue is not empty, unauthorized intercom devices E and F need to be removed from the head of the Idle_list queue to fill the corresponding BIS events in the Free_list queue. Then, unauthorized intercom devices E and F are added to the Working_list queue as authorized intercom devices. At this time, device A selects devices E and F by CTRL to become an authorized intercom device, granting it data transmission permission in the next ISO Interval. The Free_list queue is then set to empty, waiting to enter the next ISO interval.

[0075] In the third ISO Interval3: Authorized intercom device D still sends D3 and D4 data packets at the same position as in the previous ISO Interval2; although authorized intercom devices E and F have obtained data transmission permissions, they send NULL packets twice to release the BIS event because they have no data; device A selects authorized intercom devices by CTRL polling. At this time, devices A and B are selected again as authorized intercom devices, that is, added to the Working_list queue, and obtain data transmission permissions in the next ISO Interval.

[0076] In the fourth ISO Interval4: Authorized intercom devices A and B, having no data to send, both send NULL packets to release subsequent BIS events; authorized intercom device D sends D5 and D6 data packets; device A polls and selects devices C and E as authorized intercom devices, adding them to the Working_list queue, and obtaining data sending permissions in the next ISO Interval.

[0077] In the 5th ISO Interval5: Authorized intercom devices C and E send NULL packets because they have no data to send; Authorized intercom device D completes the transmission of the last D8 data packet and sends a NULL packet at D9 to release subsequent BIS events; Device A polls and selects devices F, A, and B as authorized intercom devices, that is, adds them to the Working_list queue, and obtains data transmission permission in the next ISO Interval.

[0078] The 6th equal time interval (ISO Interval6): Authorized intercom devices F, A, and B all send NULL packets because they have no data to send.

[0079] In this embodiment, the Control Subevent PDU for device scheduling is configured based on the Protocol Data Unit (PDU) packets of the Broadcast Isochronous Stream (BIS).

[0080] According to the existing Bluetooth LE Audio specification, the data structure of the Protocol Data Unit (PDU) packet for the Broadcast Isochronous Stream (BIS) includes a fixed-length Header (fixed length 16 bits), a variable-length Payload (variable length from 0 to 251 bytes), and an optional Message Integrity Check (MIC) (32 bits for encryption-related integrity verification). The meaning of the specific bits can be found in the Bluetooth specification, which is existing technology and will not be elaborated here. The Payload field includes an Opcode field and a CtrData field. For the Opcode field, values ​​from 0xF8 to 0xFB are unused. Accordingly, this embodiment preferably selects any value within this range as the Control Subevent PDU. As an example rather than a limitation, 0x02 can be selected as the Control Subevent PDU and named BIG_SCHEDULE_IND (BIG Scheduling Indication Frame).

[0081] Since the CtrData field in the Payload field can hold up to 250 bytes of content, the size of CtrData is also sufficient to accommodate the configuration information of these intercom devices when entering the next ISO interval scheduling by selecting authorized intercom devices.

[0082] Another embodiment of the present invention also provides a method for implementing a multi-device wireless intercom system, the system including multiple intercom devices with Bluetooth modules, the Bluetooth modules supporting Bluetooth Low Energy Audio (LE Audio) transmission.

[0083] See Figure 8 As shown, the method includes the following steps.

[0084] S100, Configure the master device.

[0085] S200, the master device initiates networking to establish a multi-point to multi-point transmission network, and selects the Bluetooth clock of the master device as the network clock.

[0086] S300: After establishing a multi-point to multi-point transmission network, the master device coordinates data transmission tasks within the network. Specifically, when sending a synchronization message, the master device schedules all intercom devices in the current network based on the number K of broadcast isochronous stream BIS events contained in the broadcast isochronous group BIG events within an ISO interval. Through this scheduling, BIS events are allocated to selected intercom devices so that the devices can transmit their voice data on the allocated BIS events. The number of intercom devices that can simultaneously transmit voice data within an ISO interval does not exceed K, where K is a natural number greater than or equal to 2.

[0087] Other technical features are described in the preceding embodiments and will not be repeated here.

[0088] In the above description, the disclosure of this invention is not intended to limit itself to these aspects. Rather, within the scope of the objectives of this disclosure, components can be selectively and operationally combined in any number. Furthermore, terms such as “comprising,” “encompassing,” and “having” should be interpreted by default as inclusive or open-ended, rather than exclusive or closed, unless explicitly defined as such. All technical, scientific, or other terms are to be understood by those skilled in the art, unless defined as such. Public terms found in dictionaries should not be interpreted in the context of the relevant technical documents in an overly idealistic or impractical manner, unless explicitly defined as such in this disclosure. Any modifications or alterations made by those skilled in the art based on the foregoing disclosure are within the scope of the claims.

Claims

1. A multi-device wireless intercom system, comprising multiple intercom devices with Bluetooth modules, wherein the Bluetooth modules support Bluetooth Low Energy Audio (LE Audio) transmission, characterized in that: One of the multiple intercom devices is set as the master device. The master device is used to build a multi-point to multi-point transmission network and coordinate the data transmission tasks in the network, as well as select the Bluetooth clock of the master device as the network clock. After establishing a multi-point to multi-point transmission network, the master device is configured to coordinate data transmission tasks in the network as follows: when sending a synchronization message, all intercom devices in the current network are scheduled according to the number K of broadcast isochronous stream BIS events contained in the broadcast isochronous group BIG event in an isochronous interval (ISO interval); through the scheduling, BIS events are allocated to selected intercom devices so that the intercom devices can send their own voice data on the allocated BIS events. The number of intercom devices that can send voice data simultaneously in an ISO interval does not exceed K, where K is a natural number greater than or equal to 2. The BIG event includes K BIS events and a control subevent. The master device configures and sends the control subevent, which configures network device scheduling control information for the aforementioned scheduling. During scheduling, the master device is configured to select the corresponding authorized intercom device from all intercom devices in the network through the control subevent, and configure the corresponding authorized intercom device to transmit data on one of the K BIS events.

2. The system according to claim 1, characterized in that: The first intercom device in the system is configured as the master device. The master device is configured to establish a multi-point to multi-point transmission network in the following ways: establish its own low-power Bluetooth broadcast and send broadcast data packets to initiate network formation, wherein the broadcast data packets broadcast the features it supports, including information indicating that the network supports multi-point to multi-point transmission; and when other intercom devices apply to join the aforementioned network by scanning the broadcast, an idle network ID is assigned to the intercom device according to the network registration information of the intercom device applying to join, and the new intercom device joins the aforementioned network through the network ID. After a new intercom device joins the network, when coordinating data transmission tasks in the network, the master device is also configured to: increase the total number of intercom devices in the current network by 1, and reschedule all intercom devices in the network according to the new total number of intercom devices, so that the number of intercom devices that can transmit voice data simultaneously in the network in an ISO interval does not exceed K.

3. The system according to claim 2, characterized in that: During the networking process, the other intercom devices are configured to: enable broadcast scanning, scan for broadcasts with the master device broadcast type, and select the network to join; establish a Bluetooth Low Energy (BLE) connection with the selected master device and perform security authentication; After successful security authentication, it sends network registration information to the host device to register itself and requests a network ID; Furthermore, after obtaining the network ID assigned by the master device, disconnect the Bluetooth Low Energy (BLE) connection with the master device and enter the network established by the master device according to the BIS joining process.

4. The system according to claim 1, characterized in that, The master device is configured to: obtain the number T of intercom devices in the current network; when the number T of intercom devices is greater than the number K of the aforementioned BIS events, configure the intercom devices in the network through the control sub-event Controlsubevent; select K intercom devices as authorized intercom devices from all T intercom devices in the network; and allocate idle BIS events to each of the aforementioned authorized intercom devices. One idle BIS event is allocated to one authorized intercom device. When the authorized intercom device has voice data to send, it sends its own voice data on the assigned BIS event; When the authorized intercom device has no voice data to send, it sends an empty packet (NULL) on the assigned BIS event.

5. The system according to claim 4, characterized in that, When scheduling all intercom devices in the current network, the master device is also configured to: monitor the data transmission information of each authorized intercom device in the network; when an authorized intercom device is detected sending a NULL packet, reclaim the time slot of the BIS event occupied by that authorized intercom device, and remove the intercom device whose BIS event has been reclaimed from the list of authorized intercom devices; and, Based on the recovered BIS events, configure other intercom devices in the network through the Control subevent, select new authorized intercom devices from the other intercom devices in the network, and allocate idle BIS events to each of the aforementioned new authorized intercom devices.

6. The system according to claim 5, characterized in that: When scheduling devices through the Control subevent, a Working_list queue, an Idle_list queue, and a Free_list queue are set up to store authorized intercom device information, unauthorized intercom device information, and idle BIS event information, respectively. The content of the CTRL packet of the Control subevent is determined based on the information in the Free_list queue. When the aforementioned Free_list queue is empty, keep the content of the CTRL packet of the Control subevent unchanged, and wait to enter the next ISO interval; When the aforementioned Free_list queue is not empty, select an intercom device from the unauthorized intercom devices in the Idle_list queue as a new authorized intercom device, assign an idle BIS event from the Free_list queue to the new authorized intercom device, update the information in the Working_list queue according to the new authorized intercom device, and then modify the content of the CTRL packet of the Control subevent to reconfigure the device scheduling control information so that these newly authorized intercom devices can obtain data transmission rights in the next ISO interval.

7. The system according to claim 1, characterized in that: When a walkie-talkie device that has joined the network needs to leave the network, the walkie-talkie device is configured to send a preset termination data packet on the assigned BIS event after it is selected as an authorized walkie-talkie device. When the master device receives the aforementioned termination data packet, it obtains the information of the intercom device that sent the termination data packet, removes the intercom device from the network, reduces the total number of intercom devices in the current network by 1, and then reschedules all intercom devices in the network according to the new total number of intercom devices.

8. The system according to claim 1, characterized in that: The master device is also configured to: monitor BIS events in the network; when a signal on a BIS event cannot be correctly parsed within a continuous preset number of ISO intervals, determine that the corresponding intercom device has left the network, remove the intercom device determined to be off the network from the network, reduce the total number of intercom devices in the current network by 1, and then reschedule all intercom devices in the network according to the new total number of intercom devices.

9. The system according to claim 1, characterized in that: The intercom device is one or more of Bluetooth headsets, helmet-mounted intercom headsets, and handheld intercom devices; The intercom device also includes a voice acquisition module, a codec module, a voice processing module, and a voice playback module; When the intercom device needs to send voice data, it acts as a broadcast source device. At this time, the voice acquisition module collects the raw voice data, the encoding and decoding module encodes the raw voice data to obtain an encoded voice data file, and then the Bluetooth module broadcasts the encoded voice data file to itself on the BIS event assigned to it. When the intercom device is used as a broadcast receiver to listen to the broadcast, it scans the broadcast via the Bluetooth module to obtain encoded voice data files broadcast by multiple broadcast source devices. The encoding / decoding module decodes the obtained encoded voice data files to obtain multiple decoded voice data files. The voice processing module mixes the multiple decoded voice data files to obtain mixed audio, and then plays the aforementioned mixed audio through the voice playback module.

10. A method for implementing a multi-device wireless intercom system, the system comprising multiple intercom devices having Bluetooth modules, the Bluetooth modules supporting Bluetooth Low Energy Audio (LE Audio) transmission, characterized in that... Including the following steps: Configure the master device in the system; The network is established by initiating networking through the master device to build a multi-point to multi-point transmission network, and the Bluetooth clock of the master device is selected as the network clock. After establishing a multi-point to multi-point transmission network, the master device coordinates the data transmission tasks within the network. When sending a synchronization message, the master device schedules all intercom devices in the current network based on the number K of broadcast isochronous stream BIS events contained in a broadcast isochronous group BIG event within an ISO interval. Through this scheduling, BIS events are allocated to selected intercom devices so that the devices can transmit their own voice data on the allocated BIS events. The number of intercom devices that can simultaneously transmit voice data within an ISO interval does not exceed K, where K is a natural number greater than or equal to 2. The BIG event includes K BIS events and a control subevent. The master device configures and sends the control subevent, which configures network device scheduling control information for the aforementioned scheduling. During scheduling, the master device is configured to select the corresponding authorized intercom device from all intercom devices in the network through the control subevent, and configure the corresponding authorized intercom device to transmit data on one of the K BIS events.

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