Networking method of wireless ad hoc network and communication system

Abstract

The invention discloses a networking method of a wireless ad hoc network and a communication system, the wireless ad hoc network comprises a plurality of communication devices, the plurality of communication devices comprise a master device and a slave device, the plurality of communication devices carry out networking based on a system frame structure, and the system frame structure comprises a broadcast time slot and a data time slot. The networking method comprises the steps that a frame synchronization network is established based on a broadcast time slot, the frame synchronization network is provided with a tree structure formed by master equipment and slave equipment, a root node of the tree structure is the master equipment, and other nodes except the root node are the slave equipment; and configuring dedicated data communication channels based on the frame synchronization network, wherein each dedicated data communication channel comprises a device sequence from the first device to the second device for data communication by using the dedicated data communication channel, and data time slots allocated to every two adjacent devices in the device sequence. According to the networking method of the wireless ad hoc network, networking and data communication of the wireless ad hoc network communication equipment can be realized.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and in particular to a networking method and a communication system for a wireless ad hoc network. Background Art

[0002] In a centralized network architecture, there is usually a central device, and all other devices in the network are connected to the central device to form a star topology. The central device coordinates all devices in the network. For example, for a wireless local area network, the access point (AP) is the central device, and all other devices are physically connected to the AP. The AP coordinates the wireless stations (STA) connected to it. For a cellular wireless communication system, the base station (BS) is the central device, which coordinates the communications of the user equipment (UE) within its coverage area.

[0003] A wireless ad hoc network is a temporary network composed of multiple communication devices. It can form a suitable network topology as needed, not just a star structure. Therefore, for wireless ad hoc networks, how to network multiple communication devices, how to access the network, and how to coordinate the communication between communication devices are the main problems faced by wireless ad hoc networks. Summary of the invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a networking method and communication system for wireless ad hoc network, which is used to realize the networking of wireless ad hoc network communication devices, including establishing a frame synchronization network, and realizing data communication between communication devices. The present invention also provides methods such as the system frame structure of the wireless ad hoc network, the establishment and maintenance of the frame synchronization relationship between nodes in the wireless ad hoc network, and the establishment and maintenance of a dedicated data communication channel between communication devices in the wireless ad hoc network.

[0005] One aspect of the present application provides a networking method for a wireless ad hoc network, wherein the wireless ad hoc network includes multiple communication devices, the multiple communication devices include a master device and a slave device, the multiple communication devices are networked based on a system frame structure, the system frame structure includes a broadcast time slot and a data time slot, the method includes: establishing a frame synchronization network based on the broadcast time slot, the frame synchronization network having a tree structure formed by the master device and the slave device, wherein the root node of the tree structure is the master device, and the other nodes of the tree structure except the root node are the slave devices; and configuring a dedicated data communication channel based on the frame synchronization network, each of the dedicated data communication channels includes a device sequence from a first device to a second device that uses the dedicated data communication channel for data communication, and data time slots allocated to two adjacent devices in the device sequence, the data time slots are used for data communication between the two adjacent devices, wherein each device in the device sequence is a node of the tree structure.

[0006] In some embodiments, the data communication between two adjacent devices in each of the dedicated data communication channels is unidirectional data communication.

[0007] In some embodiments, the data communication between two adjacent devices in each of the dedicated data communication channels is bidirectional data communication.

[0008] In some embodiments, the number of the broadcast time slots is not less than two, and establishing a frame synchronization network based on the broadcast time slots includes: the master device sends a frame synchronization signal in at least one of the broadcast time slots; the slave device receives a frame synchronization signal sent by other communication devices in one of the broadcast time slots, and after receiving the frame synchronization signal, takes the communication device that sends the frame synchronization signal as its parent node; the slave device determines whether it is configured as a frame synchronization relay state, and in response to being configured as a frame synchronization relay state, sends a frame synchronization signal in at least one broadcast time slot of the broadcast time slot that is not used to receive the frame synchronization signal.

[0009] In some embodiments, the master device sends a frame synchronization signal in two of the broadcast time slots.

[0010] In some embodiments, the master device sends a frame synchronization signal in one of the broadcast time slots.

[0011] In some embodiments, the frequency channel used by the master device or the slave device to send the frame synchronization signal in the broadcast time slot changes cyclically based on the system frequency hopping sequence associated with the broadcast time slot.

[0012] In some embodiments, configuring the dedicated data communication channel based on the frame synchronous network includes: the master device sending the device sequence and the allocated data time slot of each dedicated data communication channel to each slave device in the frame synchronous network through a global broadcast message.

[0013] In some embodiments, the system frame structure further includes a frequency sweeping time slot, and each of the communication devices does not transmit a signal in the frequency sweeping time slot.

[0014] In some embodiments, the system frame structure further includes a random access time slot, and the random access time slot is used for a slave device in the wireless ad hoc network to send a random access message.

[0015] In some embodiments, the slave device sending the random access message determines the channel that it can use to send the random access message based on the channel information contained in the broadcast message it received.

[0016] On the other hand, the present application provides a wireless ad hoc network communication system, wherein the wireless ad hoc network includes multiple communication devices, and the multiple communication devices are networked based on a system frame structure, and the system frame structure includes a data time slot and at least two broadcast time slots. The multiple communication devices include: a master device, which is configured to send a frame synchronization signal in at least one of the broadcast time slots; and at least one slave device, each of the slave devices is configured to receive a frame synchronization signal sent by other communication devices in one of the broadcast time slots, and after receiving the frame synchronization signal, determine whether it is configured as a frame synchronization relay state, and in response to being configured as a frame synchronization relay state, send a frame synchronization signal in at least one broadcast time slot of the broadcast time slot that is not used to receive the frame synchronization signal.

[0017] In some embodiments, the master device is configured to send a frame synchronization signal in two of the broadcast time slots.

[0018] In some embodiments, the master device is configured to send a frame synchronization signal in one of the broadcast time slots.

[0019] The present invention proposes a system frame structure including a broadcast time slot, and communication devices are organized into a frame synchronization network with a tree structure based on the broadcast time slot, and a dedicated data communication channel is configured based on the frame synchronization network, so as to establish a dedicated data communication channel for direct or relayed data communication between any two communication devices, so as to achieve the technical effect of coordinating the communication between multiple communication devices. In addition, the method of the present invention also has the advantages of easily avoiding interference within and outside the wireless ad hoc network and ensuring the end-to-end communication quality between communication devices in the wireless ad hoc network. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1The topology structure of a frame synchronization network composed of communication devices in a wireless ad hoc network communication system of an embodiment of the present disclosure is shown;

[0021] Figure 2 A schematic diagram showing a system frame structure of an embodiment of the present disclosure is shown;

[0022] Figure 3 A wireless ad hoc networking method 100 according to an embodiment of the present disclosure is shown;

[0023] Figure 4 Shows Figure 3 The sub-steps of step 110 in;

[0024] Figure 5 Shows Figure 1 A possible configuration of the broadcast time slots of each communication device in the frame synchronization network shown;

[0025] Figure 6 A schematic diagram showing an exemplary configuration of a broadcast time slot transmission channel;

[0026] Figure 7 A schematic diagram showing mapping each element of a single system frequency hopping sequence to multiple system frequency hopping sequences is shown;

[0027] Figure 8 A schematic diagram showing the channel allocation results of multiple system frequency hopping sequences;

[0028] Fig. 9 An embodiment of the configuration of a dedicated data communication channel for unidirectional data communication from node 3 to node 8 is shown;

[0029] Fig.10 One embodiment of the configuration of a dedicated data communication channel for bidirectional data communication between the node 3 and the node 8 is shown. DETAILED DESCRIPTION

[0030] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, without departing from the concept of the present invention, several variations and improvements can also be made, which all belong to the protection scope of the present invention.

[0031] Figure 1 The present invention shows a wireless ad hoc network communication system of an embodiment of the present invention, and the topology of the frame synchronization network composed of the communication devices of the wireless ad hoc network communication system. For the sake of simplicity, the wireless ad hoc network communication system is referred to as the wireless ad hoc network in the following text. Figure 1The relevant concepts used in this disclosure are explained. Figure 1 As shown, the frame synchronization network of the wireless ad hoc network disclosed in the present invention has a tree structure, and each node of the tree structure corresponds to a communication device of the wireless ad hoc network. Since there is a one-to-one correspondence between the nodes of the tree structure and the communication devices of the wireless ad hoc network, for the sake of convenience of expression, in the following text, unless otherwise specified, the nodes and communication devices of the topology structure of the wireless ad hoc network frame synchronization network can be used interchangeably.

[0032] "Communication equipment" in the present disclosure refers to equipment with wireless communication transceiver functions, and may also refer to communication units, modules, etc. in the equipment. Each communication device in a wireless ad hoc network can be distinguished by a device identifier, that is, in a wireless ad hoc network, each communication device has a unique device identifier. A communication device in a wireless ad hoc network can use a suitable channel to send or receive wireless signals in a specified time domain according to the configuration. In the present disclosure, a channel represents a frequency interval with a certain bandwidth, and a channel can be represented by a center frequency or a pre-compiled channel number. In general, two different channels do not overlap in frequency to avoid mutual interference.

[0033] In the present disclosure, multiple communication devices are networked based on the system frame structure and organized into, for example, Figure 1 The frame synchronization network with a tree structure is shown to realize various functions of the wireless ad hoc network. Figure 2 A schematic diagram of a system frame structure of an embodiment of the present disclosure is shown. Figure 2 As shown, the wireless physical resources can be divided into multiple frames in terms of time. The start time and end time of the frame define the frame boundary. From the start to the end of the frame is a frame period, and the frame is repeated with the same frame period. The frame period can be a fixed value, but can also be dynamically configured as needed, for example, the frame period can be switched at an agreed time.

[0034] In the present disclosure, each frame may include multiple time slots. According to the different functions of the time slots, the time slots may be divided into different types, such as broadcast region (BR), data slot (DS), frequency-sweeping slot (FS) and random-access slot (RS).

[0035] The broadcast time slot is used to carry the frame synchronization signal and the broadcast message. The frame synchronization signal can be used to provide a time reference, and the communication device obtains the time reference by searching the frame synchronization signal. In addition, considering factors such as the transceiver switching, there may be a certain gap between adjacent time slots (not shown in the figure). The broadcast message carried by a broadcast time slot is usually located after the frame synchronization signal in time, and the channel used to send the broadcast message is the same as the channel used to send the frame synchronization signal. Therefore, the broadcast message sent in the same broadcast time slot as the frame synchronization signal is called the broadcast message associated with the frame synchronization signal. The broadcast message includes control information, and the control information is used to control the wireless ad hoc network or communication equipment. The control information can be organized in the form of information blocks. Exemplarily, a broadcast message may include one or more information blocks, each of which includes an information type and information content. In order to distinguish between information blocks of the same type contained in different broadcast messages, the information block may also include a sequence number, and different sequence numbers correspond to different information blocks. Different information types can be defined as needed to achieve different functions.

[0036] Data slots are used for one communication device to transmit a block of data to another communication device.

[0037] The sweeping time slot is a "silent" time slot. Each communication device in the wireless ad hoc network does not send any signal during the sweeping time slot. By setting the sweeping time slot, each communication device within the wireless ad hoc network can use the sweeping time slot to measure the interference of some or all available frequencies to obtain the interference situation of the corresponding frequencies. The measurement information can be sent to the master device through the data time slot or the random access time slot, and then sent to the network control center by the master device. By setting the sweeping time slot, the external interference situation of each communication node can be obtained, so that the network control center can reasonably use and allocate wireless resources according to the channel interference situation.

[0038] The random access slot is used for the slave device to send a random access message in a contention manner, so it is also called a contention slot (CS). The random access message includes a message type and a message body. The message type indicates the type of the random access message, and the message body is the specific content of the random access message. The random access message can be various occasional messages sent by the slave device, for example, a message that can initiate a data communication request from the slave device, or a measurement report, etc. The master device or frame synchronization relay device includes the random access slot channel information in the broadcast message it sends, and monitors the random access slot. The slave device that needs to send a random access message determines the channel that can be used to send the random access message according to the channel information included in the broadcast message it receives, and sends the random access message on the channel. After the master device or frame synchronization relay device that sends the broadcast message receives the random access message, if the communication device that receives the random access message is a frame synchronization relay device, it can further forward it to its parent node through the random access slot, and the parent node further sends it to its parent node until it is forwarded to the master device, and the master device further sends it to the network control center. The network control center may perform corresponding processing according to the message type and message body of the random access message.

[0039] The system frame structure parameters such as time slot type, number, position and length can be pre-configured or dynamically configured according to different needs. Figure 2 The system frame structure shown in FIG. 1 shows an exemplary system frame structure configuration, in which a frame includes two broadcast time slots, two contention time slots, a frequency sweeping time slot and multiple data time slots. The two broadcast time slots are represented by BR1 and BR2, the two contention time slots are represented by CS1 and CS2, the frequency sweeping time slot is represented by FS, and the data time slot is represented by DS. However, it should be noted that Figure 2 The frame structure shown is only exemplary. Although two contention time slots are shown in the figure, the number of contention time slots may be less than two; if no random access message is sent, there may even be no contention time slot. However, for networking needs, according to the present disclosure, at least two broadcast time slots should be included.

[0040] In the present disclosure, in a wireless ad hoc network, based on whether the communication device needs to determine the time reference by receiving the frame synchronization signal sent by other communication devices in the wireless ad hoc network, the communication devices of the wireless ad hoc network can be generally divided into master devices and slave devices. The master device can determine the time reference by its own clock, or by receiving the synchronization signal of the external network (for example, the synchronization signal sent by the external network device or other wireless ad hoc network) or the clock signal (for example, the clock sent by the GPS, Beidou satellite system), and periodically sends the frame synchronization signal in the broadcast time slot. The slave device needs to determine the time reference by the frame synchronization signal sent by other communication devices in the wireless ad hoc network. When the slave device determines the time reference by the frame synchronization signal sent by other communication devices in the wireless ad hoc network, the slave device obtains frame synchronization with the communication device that sends the frame synchronization signal. Since each communication device that sends the frame synchronization signal has obtained frame synchronization with other communication devices, when a communication device obtains frame synchronization with other communication devices, it is equivalent to obtaining a common time reference with all communication devices that have obtained frame synchronization in the wireless ad hoc network. Therefore, it can also be expressed as the communication device obtaining frame synchronization with the wireless ad hoc network. For the sake of convenience, a slave device that has achieved frame synchronization with other communication devices can be referred to as the slave device that has achieved frame synchronization. A slave device can be configured as a frame synchronization relay state and a non-frame synchronization relay state as needed. When the slave device is configured as a frame synchronization relay state, it is a frame synchronization relay device, and when it is configured as a non-frame synchronization relay state, it is a frame synchronization terminal device. Therefore, slave devices can be further divided into frame synchronization relay devices and frame synchronization terminal devices. After achieving frame synchronization with other devices, the frame synchronization relay device also periodically sends out a frame synchronization signal for other slave devices to search for and achieve frame synchronization with it. The frame synchronization terminal device does not send a frame synchronization signal. In the present disclosure, the number of master devices is 1, and the number of slave devices can be 1 or more. Figure 1 In the exemplary wireless ad hoc network topology shown, communication device 1 is a master device, and communication devices 2-8 are slave devices. In which, exemplarily, communication devices 3, 4, 6, and 8 are configured as frame synchronization relay devices, and communication devices 2, 5, and 7 are configured as frame synchronization terminal devices.

[0041] Figure 1In the figure, an arrow from one node to another node represents the frame synchronization relationship between two communication devices. When there is an arrow from node i to node j, it means that communication device j achieves frame synchronization with communication device i by receiving the frame synchronization signal sent by communication device i, thereby achieving frame synchronization with the wireless ad hoc network, and further maintains frame synchronization with communication device i by further receiving and tracking the frame synchronization signal sent by communication device i, thereby maintaining frame synchronization with the wireless ad hoc network. Communication device i is the parent node of communication device j, and communication device j is the child node of communication device i. Here, i and j are the numbers of the nodes corresponding to the communication devices in the frame synchronization network established by the communication devices and represented by a tree structure. For example Figure 1 In the figure, communication device 2, communication device 3, communication device 6 and communication device 7 are synchronized with the wireless ad hoc network by receiving the frame synchronization signal sent by communication device 1. Communication device 1 is the parent node of communication device 2, communication device 3, communication device 6 and communication device 7, and communication device 2, communication device 3, communication device 6 and communication device 7 are child nodes of communication device 1; communication device 4 is synchronized with the wireless ad hoc network by receiving the frame synchronization signal sent by communication device 3. Communication device 3 is the parent node of communication device 4, and communication device 4 is the child node of communication device 3, and so on. It should be pointed out that Figure 1 The wireless ad hoc network topology structure formed by multiple communication devices due to frame synchronization relationship is only exemplary.

[0042] also, Figure 1 The wireless ad hoc network shown also includes a network control center (not shown in the figure), which is used to control the network locally or globally, for example, to set system parameters (including frame period, system frequency hopping sequence, etc.), to allocate physical resources to nodes, etc. It should be understood that in specific implementation, the network control center can be a separate device, or can be integrated into a communication device, such as a master device, or implemented through several communication devices. It can be implemented in software, hardware, or a combination of hardware and software.

[0043] The networking method of the wireless ad hoc network according to the embodiment of the present disclosure is described below with reference to the accompanying drawings.

[0044] Figure 3 A method 100 for establishing a wireless ad hoc network according to an embodiment of the present disclosure is shown. Specifically, the method 100 includes the following steps:

[0045] In step 110, a frame synchronization network is established based on the broadcast time slot.

[0046] The frame synchronization network is a network formed by a master device and a slave device with a frame synchronization relationship, and the frame synchronization relationship is established based on the broadcast time slot in the system frame structure, wherein the number of the broadcast time slot is at least two. Step 110 can be decomposed into sub-steps 111-115, such as Figure 4 shown.

[0047] In step 111, the master device sends a frame synchronization signal and a broadcast message in at least one broadcast time slot.

[0048] The master device can send a frame synchronization signal and a broadcast message in at least one broadcast time slot in the system frame structure according to the configuration. The specific use of the broadcast time slot not used by the master device to send a frame synchronization signal and a broadcast message is not limited and can be used for other purposes as needed.

[0049] In some embodiments, the master device may use only one broadcast time slot to send a frame synchronization signal and a broadcast message.

[0050] In some embodiments, the master node may use two or more broadcast time slots to send frame synchronization signals and broadcast messages. Compared with the case where only one broadcast time slot is used to send a frame synchronization signal, since the number of frame synchronization signals sent in one frame period increases, on the one hand, the probability of the slave device searching for the frame synchronization signal sent by the master device can be increased, and on the other hand, the selectivity of the broadcast time slot that the frame synchronization relay device can use to send the frame synchronization signal is increased, which is beneficial for the system to optimize the allocation of spectrum resources for sending frame synchronization signals and broadcast messages.

[0051] In step 113, the slave device receives a frame synchronization signal and a broadcast message sent by other communication devices in a broadcast time slot.

[0052] After the slave device is powered on, it needs to determine the time reference. It searches for the frame synchronization signal sent by the master device or other frame synchronization relay devices to obtain frame synchronization with the communication device that sends the frame synchronization signal. The communication device that sends the frame synchronization signal and broadcast message is called the parent node of the slave device, and the slave device is called the child node of the communication device that sends the frame synchronization signal and broadcast message.

[0053] After obtaining frame synchronization, the slave device further receives a broadcast message associated with the frame synchronization signal, and reads corresponding control information from the broadcast message of its parent node.

[0054] In step 115 , in response to being configured in the frame synchronization relay state, the slave device transmits a frame synchronization signal and a broadcast message in at least one broadcast time slot that is not used to receive the frame synchronization signal and the broadcast message.

[0055] According to the present disclosure, after the slave device is configured to be in the frame synchronization relay state, it becomes a frame synchronization relay device, which needs to periodically send frame synchronization signals and broadcast messages for search by communication devices that have not achieved frame synchronization. Therefore, the frame synchronization relay device receives frame synchronization signals and broadcast messages sent by other devices in one broadcast time slot, and sends frame synchronization signals and broadcast messages in another one or several broadcast time slots. It should be pointed out that the frame synchronization relay device sends the frame synchronization signal and broadcast message after it achieves frame synchronization. The broadcast message sent by the frame synchronization relay device may include control information applicable to the entire wireless ad hoc network obtained from the broadcast message of the parent node, or it may be control information applicable only to the child nodes of the frame synchronization relay device.

[0056] If the slave device is configured as a non-frame synchronization relay state, it does not need to send frame synchronization signals and broadcast messages, so its frame structure may only include one broadcast time slot for receiving frame synchronization signals and broadcast messages sent by the master node or frame synchronization relay slave node.

[0057] Those skilled in the art can understand that, through the above steps of establishing a frame synchronization network, the communication devices of the wireless ad hoc network can be organized into a network with a tree structure, and each communication device corresponds to a node of the tree structure. According to the position of the node in the tree structure, the node at the root of the tree structure can be vividly described as the root node, the node at the end of the tree structure can be described as the leaf node, and the other nodes except the root node and the leaf node can be described as the intermediate node. Among them, the root node of the tree structure corresponds to the master device, and the other nodes except the root node correspond to the slave device. The end node can only be a leaf node of the tree structure, and the frame synchronization relay device can be an intermediate node of the tree structure. When the frame synchronization relay device has no child nodes, it can also be a leaf node of the tree structure. It can be understood that the specific form of the tree structure of the frame synchronization network established by the above steps is related to multiple factors, such as the setting of the frame synchronization signal channel, the signal strength, the way the slave device searches for the frame synchronization signal, etc.

[0058] It can be understood that after the frame synchronization network is established, each communication device in the wireless ad hoc network can receive the broadcast message and thus obtain the control information.

[0059] To facilitate understanding by those skilled in the art, step 110 is described below with reference to the accompanying drawings, assuming that the number of broadcast time slots in the system frame structure is 2. Figure 5 Shows Figure 1 A possible configuration of the broadcast time slots of each communication device in a frame synchronization network is shown. Figure 5In the figure, BR1 and BR2 represent one of the broadcast time slots, the subscript "TX" indicates that the node or communication device transmits (Transmit, TX) signals in the broadcast time slot, and the subscript "RX" indicates that the node or communication device receives (Receive, RX) signals. Figure 5 As shown, node 1 is the main device, which sends frame synchronization signals and broadcast messages in both BR1 and BR2. Node 2 is a frame synchronization terminal device, which receives the frame synchronization signal and broadcast message sent by node 1 in BR1, achieves frame synchronization with node 1, and is a child of node 1. Node 3 is a frame synchronization relay device, which receives the frame synchronization signal and broadcast message sent by node 1 in BR1, achieves frame synchronization with node 1, is a child of node 1, and sends frame synchronization signals and broadcast messages in BR2. Node 4 is a frame synchronization relay device, which receives the frame synchronization signal and broadcast message sent by node 3 in BR2, and sends frame synchronization signals and broadcast messages in BR1. For the receiving and sending configuration of the broadcast time slots of the remaining nodes, it can be combined with Figure 1 The topology shown and Figure 2 The system frame structure shown is analyzed and will not be repeated here.

[0060] After a slave device is powered on, it needs to search for a frame synchronization signal to obtain frame synchronization. The device may search multiple channels in multiple consecutive frames, and may therefore find frame synchronization signals sent by multiple communication devices, which come from the master device or from multiple frame synchronization relay devices. Depending on the specific implementation, in this case, the slave device can autonomously select and determine its parent node based on the signal quality of the multiple frame synchronization signals received. For example, the device that sends the frame synchronization signal with the best signal quality is selected as the parent node; it can also be based on the broadcast message associated with the received frame synchronization signal. If the relationship between the parent node and the child node is configured in the broadcast message, and the slave device can receive the frame synchronization signal of the parent node configured for it, then the slave device determines its parent node according to the configuration of the broadcast message.

[0061] In addition, as mentioned above, the frame synchronization relay device sends the frame synchronization signal and broadcast message after it obtains frame synchronization. Figure 5 In the middle node 6, the broadcast time slot BR1 for sending the frame synchronization signal is located before the broadcast time slot BR2 for receiving the frame synchronization signal in the frame. However, only after node 6 has received the frame synchronization signal through BR2 and achieved frame synchronization, will it send the frame synchronization signal in the broadcast time slot BR1 of the subsequent frame.

[0062] like Figure 5As shown, multiple communication devices can send signals simultaneously in the same broadcast time slot. In order to avoid the interference problem caused by multiple communication devices sending signals simultaneously, the present disclosure further proposes a frequency hopping method, which can effectively avoid interference between signals sent simultaneously by multiple communication devices in the same time domain broadcast time slot in a frequency hopping manner when the number of channels is limited.

[0063] According to the frequency hopping method of the present disclosure, when the master device and the frame synchronization relay device send signals in a broadcast time slot, the frequency channels used are changed based on the system frequency hopping sequence associated with the broadcast time slot.

[0064] In the present disclosure, the system frequency hopping sequence is a channel sequence associated with the broadcast time slot used by the communication device of the wireless ad hoc network, and the communication device derives the channel of the corresponding time slot based on the system frequency hopping sequence. The system frequency hopping sequence can be pre-configured to each communication device in the wireless ad hoc network, or generated by the network control center and dynamically configured to each communication device. In some embodiments, all communication devices in the wireless ad hoc network use the same system frequency hopping sequence in the same broadcast time slot. In some embodiments, in order to prevent tracking or improve communication confidentiality, the same broadcast time slot may also correspond to multiple system frequency hopping sequences, and different communication devices may be configured with different system frequency hopping sequences in the same broadcast time slot. For the sake of convenience, the number of system frequency hopping sequences associated with each communication device in the wireless ad hoc network in the same broadcast time slot can be expressed as K, where K≥1. The kth system frequency hopping sequence can be expressed as the channel sequence f k,0 , f k,1 , …, f k,N-1 , where 0≤k≤K-1, the length of the K system frequency hopping sequences is N, f k,n (n=0, 1, ..., N-1) is the nth element of the kth system frequency hopping sequence. The number K of system frequency hopping sequences may be smaller than the number of communication devices. In this case, multiple communication devices use the same system frequency hopping sequence in the same broadcast time slot.

[0065] It should be pointed out that in the present disclosure, the channel used by the broadcast time slot of the communication device changes based on the system frequency hopping sequence associated with the time slot, which means that the channel used by the communication device to send signals in the broadcast time slot is derived from the system frequency hopping sequence associated with the broadcast time slot configured for the communication device.

[0066] In some embodiments, the channel used by the communication device to send signals in the broadcast time slot changes at fixed time intervals based on the system frequency hopping sequence. The fixed time interval uses frames as time units, that is, the fixed time interval is an integer multiple of the frame period.

[0067] In some embodiments, the channel used by the communication device in the broadcast time slot changes cyclically according to a fixed channel sequence period, and the channel sequence within a channel sequence period is a cyclic shift of the system frequency hopping sequence associated with the broadcast time slot. To facilitate understanding by those skilled in the art, the following is an example. Assume that the system frequency hopping sequence associated with a broadcast time slot used by a communication device to send a signal is f k,0 , f k,1 , …, f k,N-1 , which uses channel f in the broadcast time slot of the nth frame k,n1 , then the channel used by the broadcast time slot in the (n+1)th frame is f k,(n1+1)mod N , the channel used by the broadcast time slot in the (n+N-1)th frame is f k,(n1+N-1)mod N , where 0≤n1≤N-1, m is a positive integer, and "mod" represents a modulo operation. For a mod b (where a and b are both positive integers), the result is the remainder of a divided by b. Through the above method, the channel sequence used by the communication device to send signals in the broadcast time slot is a cyclic sequence.

[0068] In order to avoid conflicts caused by different communication devices using the same channel to send signals in the same time domain, each communication device is associated with a frequency hopping offset in each broadcast time slot used to send signals, and the frequency hopping offset indicates the offset of the channel sequence used by the communication device when sending signals in the broadcast time slot relative to the channel sequence used by the reference communication device in the reference broadcast time slot. The reference communication device and the reference broadcast time slot can be pre-configured for each communication device in the wireless ad hoc network, or adjusted by the control center as needed.

[0069] It should be noted that the length of the system frequency hopping sequence associated with the broadcast time slot for sending signals of a communication device should be the same as the length of the system frequency hopping sequence associated with the reference communication device in the reference broadcast time slot corresponding to the frequency hopping offset associated with the broadcast time slot. Even if the same system frequency hopping sequence is used in a wireless ad hoc network, by setting different frequency hopping offsets for different communication devices in the same broadcast time slot, different communication devices can use different channels to send signals in the broadcast time slot, thereby effectively avoiding signal interference between communication devices. A wireless ad hoc network can select a communication device as a reference communication device as needed, so the reference communication device can be a master device or a slave device.

[0070] Since the channel sequence used by the reference broadcast time slot of the reference communication device is a reference for other communication devices to determine the channel sequence used to send signals in their broadcast time slots based on their frequency hopping offsets, the reference broadcast time slot of the reference communication device may have no frequency hopping offset, or its frequency hopping offset may be defaulted to 0.

[0071] Since the relative value of the frequency hopping offset of each communication device obtained by selecting different nodes as the reference communication device does not change, there is no substantial difference in which communication device is selected as the reference node. Considering the ease of implementation, the main device is usually used as the reference communication device. Therefore, in the following text, unless otherwise specified, the main device is used as the reference communication device.

[0072] In some embodiments, in order to simplify the system implementation, only the same system frequency hopping sequence or multiple system frequency hopping sequences of the same length are used in the wireless ad hoc network. At this time, if the master device is a reference communication device, the first broadcast time slot of the master device is a designated broadcast time slot. For the master device, if it uses two or more broadcast time slots to send signals in a frame period, each broadcast time slot may also be associated with a frequency hopping offset, which indicates the offset of the channel sequence used by the master device when sending a signal in the broadcast time slot relative to the channel sequence used in the first broadcast time slot of the master device. At this time, the frequency hopping offset associated with the transmission broadcast time slot of the slave device is the offset of the channel sequence used in the broadcast time slot relative to the channel sequence used in the first broadcast time slot of the master device. Optionally, the master device uses the broadcast time slot with the smallest time slot number in the frame period as the first broadcast time slot. However, it should be noted that the position of the first broadcast time slot can be set as needed, for example, the broadcast time slot with the largest time slot number in the frame period can also be used as the first broadcast time slot.

[0073] The broadcast message sent by the master device in its broadcast time slot includes the frequency hopping offset associated with the broadcast time slot sent by the master device and / or the frame synchronization relay device in the wireless ad hoc network.

[0074] The frame synchronization relay device learns the difference between the frequency hopping offset associated with the broadcast time slot of the node that sends the broadcast message and the frequency hopping offset associated with its own broadcast time slot by receiving the broadcast message.

[0075] for Figure 1 The frame synchronization network shown, Figure 6 A schematic diagram showing an exemplary configuration of a broadcast time slot transmission channel, Figure 6 Each node uses Figure 5In the frame structure configuration shown, the system frequency hopping sequence used by each node is the same, which can be expressed as a channel sequence "f1, f2, f3, f4, f5, f6". Node 1 sends signals in both the first broadcast time slot BR1 and the second broadcast time slot BR2. Each broadcast time slot used for sending signals of each node in the frame synchronization network is associated with a frequency hopping offset, which indicates the offset of the channel sequence used when sending signals in its associated broadcast time slot relative to the channel sequence used by node 1 in the first broadcast time slot. At this time, the frequency hopping offsets of BR1 and BR2 of node 1 are 0 and 2 respectively, the frequency hopping offsets of node 4 and node 6 in BR1 are 3 and 1 respectively, and the frequency hopping offsets of node 3 and node 8 in BR2 are 4 and 0 respectively.

[0076] Starting from the nth frame, the channels used by node 1 to send signals on the first broadcast time slot BR1 of each frame are f1, f2, f3, f4, f5, f6, f1, f2, f3, f4, f5, f6, ... in a system frequency hopping sequence. The channels used by the master device to send signals on the second broadcast time slot BR2 of each frame are f3, f4, f5, f6, f1, f2, f3, f4, f5, f6, f1, f2, ... in a system frequency hopping sequence, but the frequency hopping offset relative to the channel sequence of BR1 is 2.

[0077] The following is an example of node 3, which is similar to the situation for other slave devices. Node 3 uses the second broadcast time slot BR2 to send signals. Starting from the nth frame, the channels used by node 1 to send signals on the first broadcast time slot BR1 of each frame are f1, f2, f3, f4, f5, f6, f1, f2, f3, f4, f5, f6, ... in a system frequency hopping sequence. The frequency hopping offset of node 3 in BR2 is 4, so starting from the nth frame, the channels used by node 3 to send signals on BR2 are f5, f6, f1, f2, f3, f4, f5, f6, f1, f2, f3, f4, ... in a system frequency hopping sequence. Figure 6 The frequency channels used by each node to send signals in the broadcast time slot from the nth frame to the n+2th frame are shown.

[0078] In the case where there are multiple system frequency hopping sequences, each channel of a single system frequency hopping sequence can be first mapped to each channel of the system frequency hopping sequence used by each node in sequence, and then based on the case of a single system frequency hopping sequence, the channel sequence used by each node for sending broadcast time slots is obtained, and then the obtained channel sequence based on the single system frequency hopping sequence is replaced with the corresponding channel sequence according to the established mapping relationship. The following is an explanation of the case of two system frequency hopping sequences, and the case of more system frequency hopping sequences is similar.

[0079] The system frequency hopping sequence 1 is represented as "A, B, C, D, E, F", and the system frequency hopping sequence 2 is represented as "G, H, I, J, K, L". Each element of each system frequency hopping sequence represents a channel. Without loss of generality, let Figure 5 Nodes 1, 3, and 4 use system frequency hopping sequence 1, and nodes 6 and 8 use system frequency hopping sequence 2.

[0080] First, each element of a single system frequency hopping sequence is mapped to each system frequency hopping sequence. The mapping relationship is as follows: Figure 7 As shown, for the system frequency hopping sequence 1, the mapping relationship 1 is f1→A, f2→B, ..., f6→F; for the system frequency hopping sequence 2, the mapping relationship 2 is f1→G, f2→H, ..., f6→L.

[0081] Then, based on the single system frequency hopping sequence "f1, f2, f3, f4, f5, f6", according to the frequency hopping offset of the broadcast time slot of each node, the channel allocation of the broadcast time slot of each node is obtained, that is, Figure 6 Results shown.

[0082] Then, for each node, the channel allocation result obtained based on a single system frequency hopping sequence is replaced with the channel of system frequency hopping sequence 1 or system frequency hopping sequence 2 according to the corresponding mapping relationship 1 or mapping relationship 2. After the above replacement, the final channel allocation is as follows: Figure 8 shown.

[0083] Those skilled in the art can understand that after the frame synchronization relay device obtains synchronization, it can determine the channel it should use when sending signals in the broadcast time slot according to the channel used by the frame synchronization signal received from the parent node, the difference between the frequency hopping offset associated with the broadcast time slot used by its parent node to send the frame synchronization signal and the frequency hopping offset associated with the broadcast time slot used by it to send the frame synchronization signal, and the system frequency hopping sequence used by it and its parent node to send the broadcast time slot. The difference between the frequency hopping offset associated with the broadcast time slot in which the frame synchronization relay device receives the frame synchronization signal sent by its parent node and the frequency hopping offset associated with the broadcast time slot in which the frame synchronization relay device sends the frame synchronization signal can be used to indicate the offset of the channel sequence used by the broadcast time slot in which the frame synchronization relay device receives the frame synchronization signal relative to the channel sequence used by the broadcast time slot in which the frame synchronization relay device sends the frame synchronization signal.

[0084] In the present disclosure, control information such as frame period, system frequency hopping sequence, node type, reference node, designated broadcast time slot of reference node, and frequency hopping offset associated with each transmitted broadcast time slot of the node can be pre-configured to each node.

[0085] After the frame synchronization network is established in step 110 , step 120 is executed.

[0086] In step 120, a dedicated data communication channel is configured based on the frame synchronous network.

[0087] A dedicated data communication channel refers to a collection of physical resources allocated to a communication device in a wireless ad hoc network for data communication with another communication device. Depending on factors such as the distance between the two communication devices, the data communication between the two communication devices may be carried out directly or through relaying by other communication devices in the wireless ad hoc network. When relaying is required through other communication devices, physical resources need to be allocated to the communication devices participating in the relay. The communication device that performs data communication relay is called a data relay device. Therefore, the dedicated data communication channel includes a device sequence from the first device to the second device via the data relay device, and data time slots allocated to each two adjacent devices in the device sequence. On this dedicated data communication channel, data is transmitted in sequence between the device sequence to realize unidirectional or bidirectional data transmission between the first device and the second device. The number of devices in the device sequence can be equal to or greater than 2. When it is equal to 2, the first device and the second device directly communicate data without the need for a data relay device; when it is greater than 2, the data communication between the first device and the second device needs to be forwarded in sequence through the data relay devices in the device sequence.

[0088] The data communication mode between two communication devices can be unidirectional data communication or bidirectional data communication. Among them, unidirectional data communication means that data is transmitted in only one direction, the party that generates data is the sender, and the final recipient of the data is the receiver. Bidirectional data communication means that data is transmitted in two directions, and either party generates data and receives data generated by the other party. Therefore, either party is both the sender and the receiver.

[0089] Those skilled in the art will appreciate that the bidirectional data communication disclosed herein adopts a time division duplex mode. In addition, the communication channel of the data communication with bidirectional communication capability can further configure whether the communication supports hybrid automatic repeat request (HARQ), and the specific configuration parameters of HARQ if HARQ is supported. When HARQ is supported, the communication device needs to provide feedback on the status of the data received in the time slot where it sends data, such as confirmation of whether the data is correctly received, in the time slot where it sends data.

[0090] In order to facilitate the understanding of those skilled in the art, Figure 1 Taking the frame synchronization network topology shown in FIG. 1 as an example, the configuration of the dedicated data communication channel is described.

[0091] Fig. 9An embodiment of the configuration of a dedicated data communication channel for unidirectional data communication from node 3 to node 8 is shown. In this embodiment, one frame includes 15 data time slots, which are denoted as DS1, DS2, ..., DS15.

[0092] like Fig. 9 As shown, the data sent from node 3 to node 8 is relayed via node 6, node 3 is the sending end, node 8 is the receiving end, and node 6 is the data relay device. The dedicated data communication channel for the one-way data communication from node 3 to node 8 via node 6 includes a data time slot DS1 allocated to node 3 for sending data to node 6, and a data time slot DS6 allocated to node 6 for sending data to node 8. The dedicated data channel can be represented by a device sequence {3, 6, 8} and an allocated data time slot {DS1, DS6}.

[0093] Fig.10 An embodiment of the configuration of a dedicated data communication channel for bidirectional data communication between node 3 and node 8 is shown. The system frame structure used in this embodiment is similar to Fig. 9 The system frame structures of the illustrated embodiments are the same.

[0094] like Fig.10 As shown, the data between node 3 and node 8 is relayed via node 6, which is a data relay device. The dedicated data communication channel includes a time slot for node 3 to communicate data with node 8, and a time slot for node 8 to communicate data with node 3. The time slot for node 3 to communicate data with node 8 includes a data time slot DS1 allocated to node 3 for sending data to node 6, and a data time slot DS6 allocated to node 6 for sending data to node 8. The time slot for node 8 to communicate data with node 3 includes a data time slot DS9 allocated to node 8 for sending data to node 6, and a data time slot DS4 allocated to node 6 for sending data to node 3. The dedicated data communication channel can be represented by a device sequence {3, 6, 8} and allocated data time slots {(DS1, DS4), (DS6, DS9)}.

[0095] The physical resources allocated to each dedicated data communication channel can be generated by the network control center, and then transmitted to each slave device of the wireless ad hoc network through a global broadcast message based on the established frame synchronization network. The nodes involved in each dedicated data communication channel send or receive on the corresponding data time slot according to the allocated physical resources.

[0096] The global broadcast referred to in the present disclosure refers to the master device sending specific information through a broadcast message, and the frame synchronization relay device that receives the broadcast message further sends the specific information in its broadcast message, so that all slave devices that can receive the broadcast message in the entire network can receive this specific information. The master device can achieve global broadcast of the specific information by setting the information type of the information block to "global broadcast" and the information content to the specific information that needs to be broadcast globally. It should be pointed out that the above method is only an exemplary method for achieving global broadcast, and global broadcast can also be achieved by other methods. The present disclosure does not impose any restrictions on the global broadcast method, as long as similar functions can be achieved.

[0097] It can be seen from the above description that in the networking method 100 of the present invention, the communication device establishes a frame synchronization network with a tree structure based on the broadcast time slot in the system frame structure. After the frame synchronization network is established, the physical resource configuration information of the dedicated data communication channel is sent through a global broadcast message. The above physical resource configuration information includes the device sequence and the allocated data time slot of each dedicated data communication channel. Each slave device can receive the configuration information, thereby establishing a dedicated data communication channel for data communication between communication devices in the wireless ad hoc network.

[0098] It should be pointed out that two adjacent devices in a device sequence of a dedicated data communication channel may have a parent-child node relationship or may not have a parent-child node relationship, thereby making the networking mode very flexible.

[0099] According to this disclosure, Figure 1 A wireless ad hoc network communication system of an embodiment of the present disclosure shown includes multiple communication devices, the multiple communication devices are networked based on a system frame structure, the system frame structure includes a data time slot and at least two broadcast time slots, and the multiple communication devices include a master device and at least one slave device. The master device is configured to execute the method and steps executed by the master device in the wireless ad hoc network networking method 100, and each slave device is configured to execute the method and steps executed by the slave device in the wireless ad hoc network networking method 100.

[0100] A person of ordinary skill in the art can understand and implement other changes to the disclosed embodiments by reading the specification and drawings, the content of the invention and the claims of the present disclosure, and they all fall within the scope of protection of the claims of the present disclosure without departing from the essence of the claims of the present disclosure. In the claims, the wording "comprising" does not exclude other elements and steps, and the words "one" and "an" do not exclude the plural. In the actual application of the present application, a part may perform the functions of multiple technical features cited in the claims. Any figure marks in the claims should not be construed as limiting the scope.

Claims

1. A method for establishing a wireless ad hoc network, characterized in that: The wireless ad hoc network includes a plurality of communication devices, the plurality of communication devices include a master device and a slave device, the plurality of communication devices are networked based on a system frame structure, the system frame structure includes a broadcast time slot and a data time slot, and the method includes: Establishing a frame synchronization network based on the broadcast time slot, the frame synchronization network having a tree structure formed by the master device and the slave device, wherein the root node of the tree structure is the master device, and other nodes of the tree structure except the root node are the slave devices; and A dedicated data communication channel is configured based on the frame synchronization network, each of the dedicated data communication channels includes a device sequence from a first device to a second device that uses the dedicated data communication channel for data communication, and data time slots allocated to two adjacent devices in the device sequence, the data time slots are used for data communication between the two adjacent devices, wherein each device in the device sequence is a node of the tree structure.

2. The method according to claim 1, characterized in that The data communication between two adjacent devices in each dedicated data communication channel is unidirectional data communication.

3. The method according to claim 1, characterized in that: The data communication between two adjacent devices in each dedicated data communication channel is bidirectional data communication.

4. The method according to claim 1, characterized in that The number of the broadcast time slots is not less than two, and establishing a frame synchronization network based on the broadcast time slots includes: The master device sends a frame synchronization signal in at least one of the broadcast time slots; The slave device receives a frame synchronization signal sent by other communication devices in one of the broadcast time slots, and after receiving the frame synchronization signal, takes the communication device that sends the frame synchronization signal as its parent node; The slave device determines whether it is configured in the frame synchronization relay state, and in response to being configured in the frame synchronization relay state, transmits a frame synchronization signal in at least one broadcast time slot that is not used to receive the frame synchronization signal.

5. The method according to claim 4, characterized in that The master device sending a frame synchronization signal in at least one of the broadcast time slots includes: The master device sends a frame synchronization signal in two of the broadcast time slots.

6. The method according to claim 4, characterized in that The master device sending a frame synchronization signal in at least one of the broadcast time slots includes: The master device sends a frame synchronization signal in one of the broadcast time slots.

7. The method according to claim 4, characterized in that The frequency channel used by the master device or the slave device to send the frame synchronization signal in the broadcast time slot changes cyclically based on the system frequency hopping sequence associated with the broadcast time slot.

8. The method according to claim 1, characterized in that Configuring a dedicated data communication channel based on the frame synchronization network includes: The master device sends the device sequence and the allocated data time slot of each dedicated data communication channel to each slave device in the frame synchronization network through a global broadcast message.

9. The method according to claim 1, characterized in that: The system frame structure also includes a frequency sweeping time slot, and each of the communication devices does not transmit a signal in the frequency sweeping time slot.

10. The method according to claim 1, characterized in that The system frame structure also includes a random access time slot, and the random access time slot is used for a slave device in the wireless ad hoc network to send a random access message.

11. The method according to claim 10, characterized in that The slave device sending the random access message determines the channel that can be used to send the random access message based on the channel information included in the broadcast message it receives.

12. A wireless ad hoc network communication system, characterized in that: The wireless ad hoc network includes a plurality of communication devices, the plurality of communication devices are networked based on a system frame structure, the system frame structure includes a data time slot and at least two broadcast time slots, and the plurality of communication devices include: a master device configured to send a frame synchronization signal in at least one of the broadcast time slots; and At least one slave device, each of the slave devices is configured to receive a frame synchronization signal sent by other communication devices in one of the broadcast time slots, and after receiving the frame synchronization signal, determine whether it is configured as a frame synchronization relay state, and in response to being configured as a frame synchronization relay state, send a frame synchronization signal in at least one broadcast time slot of the broadcast time slot that is not used to receive the frame synchronization signal.

13. The wireless ad hoc network communication system according to claim 12, characterized in that: The master device is configured to send a frame synchronization signal in two of the broadcast time slots.

14. The wireless ad hoc network communication system according to claim 12, characterized in that: The master device is configured to send a frame synchronization signal in one of the broadcast time slots.

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