Ad hoc network voice communication method based on Bluetooth

Abstract

The invention discloses a Bluetooth-based ad hoc network voice communication method, which comprises the following steps of: firstly establishing a link between communication devices by using a Bluetooth ACL asynchronous link technology, and then establishing a link between the communication devices by using a Bluetooth eSCO or CIS synchronous isochronous link technology, after the connection, forming a linear or star network topology structure between the communication devices serving as connection points, and in the networking, connecting the communication devices by using the Bluetooth ACL asynchronous link technology and the Bluetooth eSCO or CIS synchronous isochronous link technology. And the communication devices transmit data to each other and filter or forward data sent by the neighbor devices to the far-end device, so that mutual voice communication among the group members is achieved. By adopting the technical scheme of the invention, the wireless ad hoc network communication in a local area range can be met, and the wireless ad hoc network can be interconnected and intercommunicated with other Bluetooth products in a relatively universal manner.

Description

Technical Field

[0001] The invention belongs to the technical field of communication, and in particular relates to a Bluetooth-based ad hoc network voice communication method. Background Art

[0002] Mobile wireless communications have become an essential tool for people's daily work, life and entertainment, bringing great convenience to people. Generally speaking, mobile wireless communications require infrastructure support to provide the core role of interconnection. However, in remote mountainous areas where base station facilities are lacking, indoors in some buildings where signals are blocked, on-site rescue in earthquake disasters, and outdoor team riding environments, due to being far away from the city center, or entering remote areas such as snowy areas, mountains, and grasslands, there will be insufficient signal coverage or lack of basic communication facilities such as base stations, making communication difficult. Therefore, self-organizing wireless networks that do not rely on basic communication facilities become very important in specific situations.

[0003] In the existing technology, some wireless communication technologies, such as devices that transmit voice through WIFI technology, may consume more power because it is a CSMA / CA competitive channel mode; in addition, some products that use low-frequency band technology, such as 802.15.4 and sub-1Ghz technology, can use the 2.4Ghz / 900Mhz / 500Hhz frequency band, but the wireless resource regulations vary and have restrictions in each country. The most critical point is that the above technologies have no standard specification definition constraints on self-organizing network connections, which may lead to interoperability problems of products. Summary of the invention

[0004] In order to solve the deficiencies in the prior art, the present invention provides a Bluetooth-based ad hoc network voice communication method capable of realizing wireless ad hoc networking in a local area network and interconnecting with other devices.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions: A Bluetooth-based ad hoc network voice communication method, wherein communication devices first establish a link using Bluetooth ACL asynchronous link technology, and then establish a link using Bluetooth eSCO or CIS synchronous isochronous link technology. After the connection, each communication device as a connection point forms a linear or star network topology. In the networking, each communication device transmits data to each other, and filters or forwards data sent by neighboring devices to a remote device, so as to achieve mutual voice communication between group members.

[0006] Preferably, when establishing a link using Bluetooth eSCO or CIS synchronous isochronous link technology, in the same network, for communication devices that support CIS synchronous isochronous link technology, CIS synchronous isochronous link technology is preferentially used to establish a link, and for communication devices that do not support CIS synchronous isochronous link technology, eSCO synchronous isochronous link technology is used to establish a link.

[0007] Preferably, in a Bluetooth-based ad hoc network voice communication method, the connection process between communication devices includes the following steps: A new communication device sends a data packet to all its adjacent communication devices in the form of broadcast. The data packet contains the communication device's own manufacturer ID, product ID, status information, its own network topology information, and customized information; After the surrounding communication devices scan the broadcast of the new communication device, they parse the data packets; After parsing, determine whether they are the same type of device and whether a loop will be formed after connecting to the new communication device. If they are the same type of device and no loop will be formed, a connection can be initiated. If they are not the same type of device or a loop will be formed, no connection will be initiated. After the new communication device is successfully connected, it updates the broadcast content or closes its own broadcast. When updating the broadcast content, the new broadcast content informs the surrounding communication devices that it is a slave device role and its own network topology information.

[0008] Preferably, when the Bluetooth eSCO synchronous isochronous link technology is used to establish a link, the new communication device to be connected turns off its own broadcast after the connection is successful.

[0009] Preferably, when the Bluetooth eSCO synchronous isochronous link technology is used to establish a link, during the connection process between the communication devices, at the same time, one communication device notifies the surrounding devices through broadcast data that it is only in the connection initiating state or only in the connected state.

[0010] Preferably, after the communication devices are connected to each other, it is further detected whether there is a loop, and if there is a loop, the connection with the loop is disconnected.

[0011] Preferably, under the link established by using Bluetooth synchronous isochronous link technology, two links of a communication device avoid time slot conflicts by following the steps: (1) When a communication device establishes two links, it plays the role of the master device (Central role) on one link and the role of the slave device (Peripheral role) on the other link; (2) In step (1), the master role starts the piconet clock adjustment mechanism and fine-tunes the local clock with reference to its time slot window on the slave role link.

[0012] Preferably, when the master device role starts the PCA piconet clock adjustment mechanism to adjust the local clock, the eSCO window of the master device role is moved rightward or leftward cumulatively so as to maintain a proper gap with the eSCO window of the slave device role.

[0013] Preferably, the method for adjusting the local clock using the PCA piconet clock adjustment mechanism is as follows: S1, periodically checking the gap between the eSCO windows in the master device role and the slave device role, if it is found that the gap value is less than a preset threshold, the PCA piconet clock adjustment mechanism is started; S2. Set a target gap value, and set the attribute of active drift of the local clock according to the drift attribute of the slave device role clock that is statistically obtained; S3: The local clock calculates the number of times that need to be adjusted based on the target gap value, with the principle of adjusting one step per cycle. Each time the local clock changes one step based on the active drift attribute, when the number of required adjustments is completed, the target gap value is reached, and the adjustment stops; S4. After the adjustment is completed, observe the gap between the eSCO windows in the master device role and the slave device role again.

[0014] Preferably, after the communication devices are connected, each communication device serving as a connection point forms a linear or star network topology structure, thereby realizing network topology update and network topology deep optimization in the networking.

[0015] By adopting the above technical solution, the present invention has the following beneficial effects: The technical solution of the present application adopts standard Bluetooth technical specifications, searches and discovers devices in a broadcasting manner, and connects multiple devices in series in an eSCO dual-connection or CIS multi-connection manner, which can realize wireless ad hoc network communication within a local area network and complete voice calls among group members without relying on basic communication facilities, making communication between multiple devices simple and achieving a longer communication distance. At the same time, due to the use of standard Bluetooth technology, the standard is open and has been widely used in the market. It can be interconnected with other Bluetooth intercom devices, making communication more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a timing diagram based on eSCO connection in one embodiment of the present invention; Figure 2 is a timing diagram based on CIS connection in one embodiment of the present invention; Figure 3 is a schematic block diagram of a connection process between communication devices in one embodiment of the present invention; Figure 4is a schematic diagram of a Bluetooth eSCO connection model in one embodiment of the present invention; Figure 5 This is one of the schematic diagrams of the Bluetooth CIS connection model in one of the embodiments of the present invention; Figure 6 This is the second schematic diagram of the Bluetooth CIS connection model in one embodiment of the present invention; Figure 7 is a schematic diagram of a connection model in which Bluetooth eSCO and CIS coexist in one embodiment of the present invention; Figure 8 It is a schematic diagram of a new device DEV4 and a member DVE3 entering a networking mode in one embodiment of the present invention; Fig. 9 is a schematic diagram of a master-slave mode of a device in one embodiment of the present invention; Fig.10 This is a schematic diagram of eSCO connections and corresponding clocks in two roles of a device in one embodiment of the present invention; Fig.11 is a schematic diagram of adjusting a local clock using the PCA technology in one embodiment of the present invention; Fig.12 is a schematic diagram of network topology update in one embodiment of the present invention; Fig.13 It is a schematic diagram of network topology depth optimization in one embodiment of the present invention. DETAILED DESCRIPTION

[0017] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0018] The components of the embodiments of the present invention generally described and shown in the drawings herein may be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention.

[0019] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present invention.

[0020] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0021] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] Example like Figures 1 to 13 As shown, in one embodiment of the present invention, a Bluetooth-based self-organizing network voice communication method of the present invention, the communication devices first use Bluetooth asynchronous link technology to establish an ACL link to complete data communication, and then use eSCO or CIS Bluetooth synchronous isochronous link technology to establish a link to complete voice communication. After the connection, the master device can send data to the slave device, and the slave device can also send data to the master device to achieve full-duplex voice communication; each communication device as a connection point forms a linear or star network topology structure. In the networking, each communication device transmits data to each other, and filters or forwards data sent by the neighboring device to the remote device, so as to achieve mutual voice communication between group members.

[0023] The communication device is a Bluetooth headset, a Bluetooth intercom device, a smart wearable device, a Bluetooth adapter, a Bluetooth alarm or a smart home device.

[0024] Asynchronous link is also called ACL (Asynchronous connection Link), which is mainly used for transmission scenarios where real-time requirements are not very high; synchronous isochronous link can be eSCO or CIS (Connected Isochronous Stream). Among them, Bluetooth eSCO link is an improved SCO link introduced in Bluetooth core specification version 4.0. It is mainly used to transmit data with high real-time requirements, but it occupies more bandwidth. At the same time, considering retransmission, such as Figure 4As shown in Figure 1, a single communication device is generally allowed to establish at most two eSCO links; using Bluetooth CIS link technology, such as Figure 5 , Figure 6 As shown, a single communication device can establish two or even more than two voice links.

[0025] The CIS solution cannot be implemented on some earlier Bluetooth chips. Such communication devices can only use the eSCO synchronous isochronous link technology to establish a link. This is one of the specific embodiments. Figure 4 shown.

[0026] For a Bluetooth chip supporting CIS, the CIS link is used to replace the eSCO link. This is another specific embodiment. Figure 5 , Figure 6 shown.

[0027] In a more preferred embodiment, since the CIS link is better than the eSCO link in the design of the retransmission mechanism, it is more suitable for the scenario of this solution. In the same network, for communication devices that support the CIS synchronous isochronous link technology, the CIS synchronous isochronous link technology is preferentially used to establish a link, and for communication devices that do not support the CIS synchronous isochronous link technology, the eSCO synchronous isochronous link technology is used to establish a link. Figure 7 shown.

[0028] That is, when establishing a link using Bluetooth eSCO or CIS synchronous isochronous link technology, multiple communication devices can be networked in series using the eSCO dual-connection mode, or multiple communication devices can be networked in series using the CIS multi-connection mode. eSCO and CIS can also be used simultaneously for networking. When eSCO and CIS are used simultaneously, the CIS link is used first.

[0029] Full Duplex means that both parties can send and receive data at the same time, that is, data can be transmitted in both directions at the same time. In this mode, the transmitter and receiver of the communication device can work at the same time without switching directions, so there is no time delay caused by the switching operation.

[0030] A linear network topology consists of several devices connected in sequence along a straight line. In a linear topology, each device has only two adjacent connection points, which are connected to the previous device and the next device respectively.

[0031] A star network topology in which all nodes are directly connected to a central node, forming a star shape; the central node acts as the hub or switch of the network, responsible for forwarding and routing data.

[0032] When the network is complete, each communication device as a connection point can not only send its own voice data to neighboring devices, but also forward the received voice data to other devices, thereby achieving a longer communication distance. For example, A connects to B, and B connects to C, then B can send its own voice information to A and C, can send the received voice information of C to A, and can send the received voice information of A to C.

[0033] Furthermore, the connection process between the communication devices includes the following steps: A new communication device sends a data packet to all its neighboring communication devices in the form of broadcast. The data packet contains the communication device's own vendor ID, product ID, status information, its own network topology information, and customized information. The vendor ID is used to uniquely identify a company. By parsing the vendor ID and product ID, the manufacturer and product type of the device can be identified. The status information is the current state of the communication device itself, including the state of initiating connection, being connected, or standby. The network topology is generated using the internal minimum spanning tree algorithm. Customized information refers to commonly used Bluetooth addresses, connected group members, and other information.

[0034] After the surrounding communication devices scan the broadcast of the new communication device, they parse the data packets; After parsing, determine whether they are the same type of device and whether a loop will be formed after connecting to the new communication device. If they are the same type of device and no loop will be formed, initiate a connection. If they are not the same type of device or a loop will be formed, do not initiate a connection. By parsing the manufacturer ID in the broadcast data packet, the type of device can be identified; A loop refers to a ring formed between network devices. Communication is carried out through the links on the ring. If one of the links fails, the entire network will have problems. Therefore, in order to avoid expanding the scope of the failure, it is necessary to avoid the formation of loops as much as possible.

[0035] In another embodiment, a data packet sent by a new communication device to all its adjacent communication devices in the form of a broadcast also includes a service UUID. The service UUID is a universally unique identifier. The UUID is used to identify the services supported by the device. By parsing the service UUID, the type of device can be identified more accurately.

[0036] Optionally, when the communication device supports CIS, CIS communication is preferentially used.

[0037] After the new communication device is successfully connected, it exchanges its own network topology information with the communication device at the other end, and then updates the broadcast content or turns off its own broadcast. When updating the broadcast content, the new broadcast content informs the surrounding communication devices that it is a slave device role (Peripheral role) and its own network topology information.

[0038] When two communicating devices exchange their own network topology information, if CIS connection is used, they can interact through BLE's GATT. If BT connection is used, a private L2CAP channel is established first, and then the interaction is carried out.

[0039] Furthermore, when the Bluetooth eSCO synchronous isochronous link technology is used to establish a link, the new communication device to be connected turns off its own broadcast after the connection is successful, so as to prevent the situation where it is connected again and becomes two Peripheral roles.

[0040] Furthermore, when Bluetooth eSCO synchronous isochronous link technology is used to establish a link, during the connection process between communication devices, at the same time, a communication device notifies peripheral devices through broadcast data that it is only in the state of initiating a connection or only in the state of being connected. The role of initiating a connection or being connected can be announced through broadcasts. For example, when a communication device only receives connections, this position in the broadcast data is set to 0. Conversely, if a communication device wants to initiate a connection, the data position in the broadcast is set to 1. Only when the peripheral device scans the broadcast and the status is 0 can it initiate a connection to the communication device. The advantage of adopting this solution is to prevent a communication device from being connected to other communication devices during the process of initiating a connection.

[0041] Furthermore, after the communication devices are connected to each other, it is further detected whether there is a loop, and if there is a loop, the connection with the loop is disconnected.

[0042] like Figure 8 As shown in the figure, the new device DEV4 and the member DEV3 enter the networking mode, both send broadcasts and scan each other's broadcasts. Once a valid new member is found, such as one that does not form a loop topology and is a Bluetooth device of the same type and within the communication range, a communication connection will be established. When DEV3 and DEV4 are successfully connected, an audio link is established.

[0043] In addition, since the local Bluetooth clocks of each communication device have errors, the Bluetooth specification defines that in the active state, the clock error is recommended not to exceed 20ppm, and in low-power mode, the allowed error will be larger. In each link, one end is the master device role (Central role) and the other end must be the slave device role (Peripheral role), where the master device role uses the local clock (native clock), and the slave device role needs to track and synchronize to the master device role's clock (remote clock). Figure 4 or Figure 5 , Figure 6 When connected, the device may have two links. Since it is the master device, the clock error (slowing down or speeding up) is random and uncertain, which may cause time slot conflicts between the two link data windows on a communication device.

[0044] In this case, when establishing a link using Bluetooth synchronous isochronous link technology, the two links of a communication device can avoid time slot conflicts by the following provisions: Provision (1) that when a communication device establishes two links, the communication device plays the role of a master device (Central role) on one link and plays the role of a slave device (Peripheral role) on the other link; When a communication device receives a data packet broadcast by another communication device and parses the existing connection information between the two devices, it can make an accurate judgment on who initiated the connection establishment, thereby satisfying regulation (1).

[0045] Provision (2), under provision (1), the master role starts the PCA piconet clock adjustment mechanism, and fine-tunes the local clock with reference to its time slot window on the slave role link, such as the ClockDragging method, to avoid time slot collision between the two windows.

[0046] like Fig. 9 As shown, according to the above provisions (1) and (2), each node can avoid collision of the voice time slot windows of the two links.

[0047] Specifically, Fig. 9 As shown in the figure, taking device DEV2 as an example, device DEV2 is connected to two devices DEV1 and DEV3. Device DVE2 acts as the master device and slave device on the two eSCO links respectively. The two roles correspond to two clocks respectively. The clock of the slave device role follows the clock of the remote device (remote clock), and the clock of the master device role is based on the local clock (native clock).

[0048] like Fig.10 As shown in the figure, the eSCO windows (eSCO window is the eSCO window, indicated by the box graphic in the figure) on the two eSCO links send and receive voice data. Due to the existence of two clocks, and the two clocks will have certain random errors and accumulations during operation, after a period of time, the eSCO windows may be close to or even overlap. In order to avoid this problem, the master device role starts the PCA piconet clock adjustment mechanism to fine-tune the local clock, that is, dynamically adjust the local clock to speed up or slow down to ensure the gap (Margin) between the two eSCO windows.

[0049] like Fig.11 As shown in the figure, when the master role starts the PCA piconet clock adjustment mechanism to adjust the local clock, the eSCO window of the master role is moved to the right or left cumulatively ( Fig.11 In one embodiment, the method of adjusting the local clock using the PCA technology is as follows: S1, periodically checking the gap between the eSCO windows in the master device role and the slave device role, if the gap value is found to be less than a preset threshold, the PCA piconet clock adjustment mechanism is started; S2. Set a target gap value, and set the attribute of active drift of the local clock according to the drift attribute of the slave device role clock (the drift attribute is left or right). S3. The local clock calculates the number of times that need to be adjusted based on the target gap value, with the principle of one step per cycle. Each time the clock changes the local clock by one step according to the active drift attribute. When the number of times that need to be adjusted is completed, the target gap value is reached and the adjustment stops. For example, a cycle may be 50 milliseconds, and a step may be 2 microseconds. Each clock, that is, 2 microseconds are added or subtracted from the local clock; when the target gap value is reached, the adjustment stops. It should be noted that the step amplitude should not be too large, and the cycle of each adjustment can also be set according to the actual situation.

[0050] S4. After the adjustment is completed, observe the gap between the eSCO windows in the master device role and the slave device role again; S5. Repeat S1-S4.

[0051] Furthermore, after the communication devices are connected, a linear or star network topology is formed between the communication devices serving as connection points, thereby realizing network topology update and deep optimization of network topology in the networking.

[0052] The specific manifestation of network topology update is: after the network is generated, the packet receiving rate of each connection point (the ratio of the number of successfully received data packets to the total number of sent data packets during network transmission) and the surrounding signal quality (RSSI, i.e. Received Signal Strength Indication, is the received signal strength indication) can be counted. When the packet receiving rate is lower than a threshold and there are better options around, switch to the optimal network to complete the network topology update. Fig.12 , the network connection form shown on the left is device DEV1-device DEV2-device DEV3, that is, device DEV1 and device DEV2 are connected to each other, and device DEV2 and device DEV3 are connected to each other. When the device packet receiving rate and the surrounding signal quality change to Fig.12 When the connection point status on the right is on, the network topology is updated, and the network connection form is switched to device DEV1-device DEV3-device DEV2, that is, device DEV1 and device DEV3 are connected to each other, and device DEV2 and device DEV3 are connected to each other.

[0053] The network topology depth optimization is as follows: after the network topology is generated, the shortest path is calculated in real time through an internal algorithm based on the network topology broadcast by the surrounding communication devices. If the signal quality of the surrounding devices meets the set value and can reduce the maximum depth of the entire network topology, the current connection is disconnected and the optimal connection is selected. Fig.13 As shown, the original network connection form is device DEV1-device DEV2-device DEV3-device DEV4, with a depth of 3. Device DEV1 is connected to device DEV2, device DEV2 is connected to device DEV3, and device DEV3 is connected to device DEV4. Device DEV4 needs to be forwarded through device DEV3 when connected to device DEV2. After optimization, the network connection form is switched to device DEV2 being connected to device DEV1, device DEV4, and device DEV3 respectively, with a depth of 2.

[0054] The above embodiments do not impose any formal limitations on the shape, material, structure, etc. of the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are within the protection scope of the technical solution of the present invention.

Claims

1. A Bluetooth-based ad hoc network voice communication method, characterized in that: The communication devices first establish a link using Bluetooth ACL asynchronous link technology, and then use Bluetooth eSCO or CIS synchronous isochronous link technology to establish a link. After the connection, the communication devices that serve as connection points form a linear or star network topology. In the networking, the communication devices transmit data to each other and filter or forward data sent by neighboring devices to remote devices, so as to achieve mutual voice communication between group members.

2. A Bluetooth-based ad hoc network voice communication method according to claim 1, characterized in that: When establishing a link using Bluetooth eSCO or CIS synchronous isochronous link technology, in the same network, for communication devices that support CIS synchronous isochronous link technology, CIS synchronous isochronous link technology is used to establish a link first, and for communication devices that do not support CIS synchronous isochronous link technology, eSCO synchronous isochronous link technology is used to establish a link.

3. A Bluetooth-based ad hoc network voice communication method according to claim 1 or 2, characterized in that: The connection process between communication devices includes the following steps: A new communication device sends a data packet to all its adjacent communication devices in the form of broadcast. The data packet contains the communication device's own manufacturer ID, product ID, status information, its own network topology information, and customized information; After the surrounding communication devices scan the broadcast of the new communication device, they parse the data packets; After parsing, determine whether they are the same type of device and whether a loop will be formed after connecting to the new communication device. If they are the same type of device and no loop will be formed, a connection can be initiated. If they are not the same type or a loop will be formed, no connection will be initiated. After the new communication device is successfully connected, it updates the broadcast content or closes its own broadcast. When updating the broadcast content, the new broadcast content informs the surrounding communication devices that it is a slave device role and its own network topology information.

4. The Bluetooth-based ad hoc network voice communication method according to claim 3, characterized in that: When the Bluetooth eSCO synchronous isochronous link technology is used to establish a link, the new communication device to be connected will turn off its own broadcast after the connection is successful.

5. The Bluetooth-based ad hoc network voice communication method according to claim 3, characterized in that: When a link is established using Bluetooth eSCO synchronous isochronous link technology, during the connection process between communication devices, at the same time, one communication device notifies the surrounding devices through broadcast data that it is only in the initiating connection state or only in the connected state.

6. The Bluetooth-based ad hoc network voice communication method according to claim 3, characterized in that: After the communication devices are connected to each other, it is further detected whether there is a loop. If there is a loop, the connection with the loop is disconnected.

7. The Bluetooth-based ad hoc network voice communication method according to claim 3, characterized in that: In a link established using Bluetooth synchronous isochronous link technology, two links of a communication device avoid time slot conflicts by following the steps below: (1) When a communication device establishes two links, it plays the role of the master device on one link and the role of the slave device on the other link; (2) In step (1), the master role starts the piconet clock adjustment mechanism and fine-tunes the local clock with reference to its time slot window on the slave role link.

8. The Bluetooth-based ad hoc network voice communication method according to claim 7, characterized in that: When the master device role starts the PCA piconet clock adjustment mechanism to adjust the local clock, the eSCO window of the master device role is moved rightward or leftward cumulatively to maintain an appropriate gap with the eSCO window of the slave device role.

9. A Bluetooth-based ad hoc network voice communication method according to claim 8, characterized in that: The method of adjusting the local clock using the PCA piconet clock adjustment mechanism is as follows: S1, periodically checking the gap between the eSCO windows in the master device role and the slave device role, if it is found that the gap value is less than a preset threshold, the PCA piconet clock adjustment mechanism is started; S2. Set a target gap value, and set the attribute of active drift of the local clock according to the drift attribute of the slave device role clock that is statistically obtained; S3: The local clock calculates the number of times that need to be adjusted based on the target gap value, with the principle of adjusting one step per cycle. Each time the local clock changes one step based on the active drift attribute, when the number of required adjustments is completed, the target gap value is reached, and the adjustment stops; S4. After the adjustment is completed, observe the gap between the eSCO windows in the master device role and the slave device role again.

10. The Bluetooth-based ad hoc network voice communication method according to claim 3, characterized in that: After the communication devices are connected, each communication device serving as a connection point forms a linear or star network topology structure, realizing network topology update and deep optimization in the networking.

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