Optimized wireless channel link layer transmission control method

Abstract

The invention relates to an optimized wireless channel link layer transmission control method, which belongs to the technical field of ad hoc networks, and comprises the following steps of: establishing a multi-node ad hoc network for transmitting data through a superframe; the superframe sequentially comprises a reserved frame and an information frame, and the reserved frame comprises a plurality of frequency domain slices; each frequency domain slice sequentially comprises a time slot request time slice, a time slot response time slice and a broadcast time slice; each sending node sends a grouping request in the time slot request time slice of the corresponding frequency domain slice; the grouping request comprises a reservation information frame selected according to an own time slot state list; the target receiving node confirms the information frame reserved by the sending node based on the time slot state list of the target receiving node, and sends a grouping response in the time slot response time slice of the corresponding frequency domain slice; the sending node receives a response at the time slot response time slice; the sending node and the target receiving node broadcast the updated time slot state list in the broadcast time slice; and the sending node and the target receiving node send and receive data according to the reserved information frame.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of self-organizing network technology, and particularly relates to an optimized wireless channel link layer transmission control method. BACKGROUND

[0002] A wireless ad-hoc network is composed of a group of wireless mobile nodes, does not need to rely on fixed communication network infrastructure, and can be quickly deployed. It is a network without network center entity, self-organizing and self-healing. Each network node cooperates with each other, communicates and exchanges information through wireless links, and realizes the sharing of information and services. The nodes in the network can move randomly, can dynamically and frequently join and exit the network, and will not damage the communication of other nodes in the network.

[0003] In a wireless ad-hoc network communication system, the wireless channel link layer as a key bridge between the network layer and the physical layer undertakes the important responsibility of connecting the upper and lower layers. Its role mainly reflects in the following aspects: data transmission control: encapsulates and checks the data to ensure reliable transmission of the upper layer application data; link management: the link layer is responsible for the establishment, maintenance and release of the wireless link; channel access control: determines how multiple devices share the wireless channel through formulating reasonable rules, avoids data transmission conflict, and improves the utilization rate of the wireless channel and the data transmission efficiency. Physical layer adaptation: according to the transmission capacity and channel conditions of the physical layer, selects appropriate modulation and demodulation mode, coding scheme and other parameters to optimize the data transmission performance. The wireless channel link layer in the wireless ad-hoc network communication system guarantees the efficiency and reliability of data transmission from multiple dimensions, and the effective implementation of its functions plays a decisive role in the performance of the entire wireless communication network. At present, the wireless channel link layer transmission control method mainly includes time division multiple access (TDMA), carrier sense multiple access (CSMA), polling, random access and hybrid mode.

[0004] Time division multiple access (TDMA) divides time into periodic time slots and allocates specific time slots for different users to transmit data. Although this method can avoid conflict, the time slot allocation lacks flexibility, and when the service traffic dynamically changes, it is easy to cause waste of time slot resources and cannot fully meet the burst service demand. Carrier sense multiple access (CSMA) listens to the channel before sending data, and sends when the channel is idle. However, in a node-dense environment, even if the node listens to the channel to be idle, multiple nodes may send data at the same time due to signal propagation delay, causing conflict and reducing transmission efficiency. The working principle diagram of the CSMA protocol is as follows: Figure 3The polling mode is inquired by the center node in turn whether the data is sent, and since the center node needs to poll all nodes, when the number of nodes is large, the polling cycle is long, the data transmission delay is increased, and it is difficult to meet the real-time service requirements. Although the random access mode is simple and flexible, in the high load condition, the nodes frequently conflict, the number of backoff times increases, resulting in a significant decrease in channel utilization and deterioration of transmission performance. Although the hybrid mode combines the advantages of multiple methods, there are problems such as complex control logic and large switching delay when switching between different control modes, which affects the overall transmission performance.

[0005] The existing wireless channel link layer transmission control method has defects in resource utilization efficiency, transmission reliability, real-time guarantee and the like, and cannot meet the growing diversified business demands, and a more efficient, reliable and flexible wireless channel link layer transmission control method is urgently needed. SUMMARY

[0006] In view of the above analysis, the embodiments of the present application aim to provide an optimized wireless channel link layer transmission control method to solve the problems of low resource utilization efficiency and real-time performance of the existing wireless channel link layer transmission control method.

[0007] The embodiments of the present application provide an optimized wireless channel link layer transmission control method, which establishes a multi-node ad hoc network for transmitting data in superframes; the superframes include a reservation frame and a plurality of information frames in turn, and the reservation frame includes a plurality of frequency domain slices corresponding to each node; each frequency domain slice includes a time slot request time slice, a time slot response time slice and a broadcast time slice in turn;

[0008] Each sending node sends a packet request in the time slot request time slice of the corresponding frequency domain slice; the packet request includes a reserved information frame selected according to the time slot state list of itself;

[0009] The target receiving node confirms the information frame reserved by the sending node based on the time slot state list of itself, and sends a packet response in the time slot response time slice of the corresponding frequency domain slice, while updating the time slot state list of itself;

[0010] The sending node receives the response in the time slot response time slice and updates the time slot state list of itself;

[0011] The sending node and the target receiving node broadcast the updated time slot state list in the broadcast time slice;

[0012] The sending node and the target receiving node send and receive data according to the reserved information frame.

[0013] Further, the content of the grouping request includes a source address, a destination address, a frequency domain slice serial number occupied by the sending node, a serial number of the information frame reserved by the sending node, a data transmission priority and a data transmission frequency band; wherein the neighbor node of the sending node judges whether it is the target receiving node based on the destination address in the grouping request.

[0014] Further, the content of the grouping response includes a source address, a destination address, a response code, a serial number of the information frame allowed, a data transmission priority and a data transmission frequency band; wherein the sending node confirms the grouping request sent by it based on the serial number of the information frame allowed in the response.

[0015] Further, each target receiving node generates a response according to the data transmission priority and the serial number of the information frame reserved in the grouping request sent by each sending node; the content of the response includes a time slot request allowed response, a time slot request partially allowed response, a time slot request rejected response or a time slot request conflict response.

[0016] Wherein, the target receiving node confirms whether the information frame reserved by the sending node is allowed to be received by itself based on the time slot state list; if the information frame reserved is allowed to be received by itself, the content of the response is the time slot request allowed response; if the information frame reserved is partially allowed to be received by itself, the content of the response is the time slot request partially allowed response; if the information frame reserved is not allowed to be received by itself, the content of the response is the time slot request rejected response; if there are multiple source addresses of the information frame reserved from the same frequency domain slice in the same reserved frame, the content of the response is the time slot request conflict response.

[0017] Further, each sending node updates the time slot state list according to the response sent by its target receiving node, including:

[0018] If the response code is the time slot request allowed response, the time slot state list is updated according to the content of the grouping request sent and a broadcast is sent;

[0019] If the response code is the time slot request partially allowed response, the time slot state list is updated according to the serial number of the information frame allowed and a broadcast is sent, and the network layer is informed that this time the grouping request is partially allowed, and the sending node waits for the next superframe to resend the grouping request for the part not sent;

[0020] If the response code is the time slot request rejected response, the time slot state list is updated to include the failure of the information frame reserved by the grouping request sent, and a broadcast is sent, and the network layer is informed that this time the grouping request is failed, and the sending node waits for the next superframe to resend the grouping request;

[0021] If the response code is a time slot request conflict response, updating the time slot state list content includes sending a packet request decoding failure and issuing a broadcast, while informing the network layer that the packet request sending fails this time, and waiting for the subsequent superframe to reissue the packet request sending;

[0022] If no response code is received within a specified time, updating the time slot state list content includes issuing a broadcast that this packet request sending encounters a collision and waiting for the next superframe to reissue the packet request sending.

[0023] Further, the identity codes of the sending nodes are mapped to corresponding frequency domain slices through a hash algorithm.

[0024] Further, the bandwidths of the plurality of frequency domain slices are equal, and a guard interval is left between the frequency domain slices.

[0025] Further, the sending nodes and the target receiving nodes send and receive data according to the reserved information frames, including that in the plurality of information frames, the sending nodes send data according to the data transmission frequency band determined by the packet request sending and the packet response and the reserved information frames, and the target receiving nodes receive and process the information sent by the corresponding sending nodes in the determined data transmission frequency band and the reserved information frames.

[0026] Further, if the information of a node in the time slot state list is not updated for more than a preset number of superframes, the contents of the time slot state list are deleted by the remaining nodes when updating the time slot state list.

[0027] Further, if the response code is a time slot request conflict response, each sending node retreats to a different subsequent superframe to re-send a packet request according to a data transmission priority.

[0028] Compared with the prior art, the present application can achieve at least one of the following beneficial effects:

[0029] 1. The present application designs a wireless channel link layer transmission control method that combines the advantages of TDMA and CSMA, including a reservation frame and a plurality of information frames; the reservation frame is divided into a plurality of frequency domain slices; each frequency domain slice successively includes a time slot request time slice, a time slot response time slice and a broadcast time slice; no frame interval is required between the time slices; a plurality of sending nodes can simultaneously send packet requests in the time slot request time slice of the reservation frame; a plurality of target receiving nodes can simultaneously send packet responses in the time slot response time slice of the reservation frame; the overhead of control frames is reduced, and the data transmission efficiency is improved; an optimized resource allocation strategy is adopted to realize dynamic and flexible allocation of time slots, frequency bands and other resources, and to improve the channel resource utilization rate; thereby the overall performance of the wireless self-organizing network link layer is improved, and the practicability and reliability of the network are enhanced.

[0030] 2、The packet request content sent by the multiple sending nodes in the time slot request time slice in the form of broadcast includes the source address of the sending data, the destination address, the frequency domain slice serial number occupied by the sending node, the information frame serial number of the data transmission reservation, the data transmission priority and the data transmission frequency band; wherein the neighbor node of the sending node judges whether it is the target receiving node based on the destination address in the packet request. Each receiving node judges whether it is the target receiving node according to the destination address, and judges whether it can allow data reception in the reserved information frame serial number according to the broadcast data transmission priority and the information frame serial number of the sending data reservation. The time slot allocation certainty of TDMA and the dynamic flexible access feature of CSMA are combined, which can not only avoid the waste of idle time slots caused by the fixed time slot allocation of TDMA protocol, but also reduce the probability of data conflict compared with the CSMA protocol in the multi-node and high-load environment, and optimize the use efficiency of wireless resources. The transmission time arrangement is made in a full-distributed, parallel and fast manner based on local network information, idle monitoring and retransmission conflict are reduced, and the energy consumption of the whole communication system can be reduced.

[0031] 3、The broadcast sending mechanism and the packet request content of the application allow the nodes to allocate the reserved information frame as the transmission time slot when the network structure and the bandwidth demand change.

[0032] 4、In the application, each node transmits and receives data in the reserved frame to keep accurate timing, so as to synchronize the time slots in the whole network; the channel used by the wireless network is a wideband channel, and there can be multiple available channels for transmitting data in the information frame.

[0033] 5、The data transmitted and received in different frequency domain slices will not interfere with each other; the link between each pair of transmitting and receiving nodes is a symmetrical channel, and the two nodes can normally communicate with each other without interfering with each other.

[0034] 6、During the operation of the protocol, the nodes can move but the topology changes slowly, once a transmission time arrangement is calculated, the TDMA transmission time arrangement can still be used for a period of time before the network topology changes force another transmission time arrangement (or update) to be made.

[0035] In the application, the above technical solutions can be combined with each other to realize more preferred combination schemes. Other features and advantages of the application will be described in the subsequent specification, and some advantages will become apparent from the specification or can be understood by implementing the application. The purpose and other advantages of the application can be achieved and obtained from the contents specifically pointed out in the specification and the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0036] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the principles of the application. In the drawings:

[0037] Figure 1 A schematic diagram of the superframe structure of the present application;

[0038] Figure 2 A schematic diagram of the contention and data transmission of the present application;

[0039] Figure 3 A schematic diagram of the working principle of the conventional CSMA protocol;

[0040] Figure 4 A network topology diagram of the data transmission network of the self-organizing network of the embodiment of the present application. DETAILED DESCRIPTION

[0041] The preferred embodiments of the present application will be described in detail below with reference to the drawings, in which the same reference numerals denote the same elements throughout the drawings, and the principles of the present application are explained with the embodiments of the present application serving to illustrate the principles of the present application, but not to limit the scope of the present application.

[0042] One specific embodiment of the present application discloses an optimized wireless channel link layer transmission control method, as shown in Figure 1 and Figure 2 , which specifically includes steps S1-S5.

[0043] Step S1, a multi-node self-organizing network is established to transmit data in superframes; the superframes include a reservation frame and multiple information frames in sequence, the reservation frame includes multiple frequency domain slices corresponding to each node; each frequency domain slice includes a time slot request time slice, a time slot response time slice and a broadcast time slice in sequence.

[0044] The multiple frequency domain slices have equal bandwidth, and a guard interval is left between each frequency domain slice.

[0045] A self-organizing network topology diagram of the embodiment is shown in Figure 4 , in which there are 8 nodes in the network, and the dashed arrows represent the wireless communication links between the nodes.

[0046] The frame structure provided by the embodiment is shown in Figure 1 .

[0047] Specifically, in the time domain, the frame structure channel is divided into two functional parts, a contention period and a user information period.

[0048] The competition period is used to complete the competition of required time slots and the update of transmission time arrangement; the competition period is before the information period and is composed of a reservation frame (RF); in the frequency domain, one reservation frame is divided into M frequency domain chips (RC); for a given broadband wireless network, the parameter M needs to be configured according to the transmission bandwidth of the target broadband wireless network. In the time domain, each frequency domain chip is divided into 3 time slices:

[0049] a) The first time slice is a time slot request time slice, which is used to send a packet request RTS;

[0050] b) The second time slice is a time slot response time slice, which is used to transmit a packet response CTS;

[0051] c) The third time slice is a broadcast time slice, which is used for broadcasting the update of transmission time arrangement.

[0052] The user information period is used to transmit user data, and the user information period is composed of N information frames (IF) with equal length TIF. Among the N information frames, K (K < N) consecutive information frames can be recombined into a large information frame for transmitting a packet data.

[0053] In the competition period, the time slot competition function and the time slot allocation function are completed. The node completes the competition and allocation of its required time slots and the number of information frames thereof by using the RTS / CTS control packet interaction, and finally synchronously updates the transmission time arrangement of the whole network through the broadcast mechanism. The system generates one or more transmission time arrangements for sending packet data according to the real-time network conditions (such as node density, link quality). Then in each information frame (IF) of the information period, the generated transmission time arrangements are used until a new scheduling scheme is generated in the next competition period. The competition period and the information period work alternately and are repeated in turn.

[0054] In the user information period, the network node has the ability to flexibly schedule all information frames. Relying on the dynamic resource reservation mechanism, the node can flexibly allocate frequency resources and transmission time slots for single node, multiple nodes or even all adjacent nodes according to actual business needs, to realize accurate and efficient transmission of data. When the network topology structure changes or the bandwidth demand between nodes fluctuates, the transmission arrangements of the previous and next periods will be dynamically adjusted in time, avoiding conflicts in the process of network data transmission and ensuring the efficiency and accuracy of information transmission.

[0055] In each information frame, each node performs the operation of directional transmission and reception of packet data with adjacent nodes according to the user information time schedule. The number of information frames occupied by a node for data transmission in a single transmission process, and the designated target receiving node depend on the type and size of the data being transmitted by the node. The protocol meets these transmission requirements by periodically updating the user information time schedule (time slot status list) in the contention period.

[0056] Both the packet request and the packet response control packets carry time schedule (time slot reservation) information, which has two functions: one is used for the negotiation and adjustment of time slot allocation between the sending node and the receiving node, and the other is used for the sending node to compete with surrounding sending nodes and the receiving node to compete with surrounding receiving nodes for time slots. The role of competition is for the sending node to compete with all adjacent nodes within one hop and two-hop range for the right to transmit time slots, and for the receiving node to compete with all adjacent nodes within one hop and two-hop range for the right to receive time slots.

[0057] Step S2: Each sending node transmits a packet request in the time slot request time slice corresponding to the frequency domain slice; the packet request includes the reserved information frame selected according to the time slot status list of the sending node.

[0058] The identity codes of the sending nodes are mapped to the corresponding frequency domain slices by a hash algorithm.

[0059] Specifically, the unique identity code ID value of the network node is calculated by a hash function using a hash randomization algorithm to obtain a hash value, and the network node is mapped to different frequency domain slices. If the hash function is designed properly, it can uniformly distribute network nodes to each frequency domain slice, reducing the probability of conflict when multiple network node objects are mapped to the same frequency domain slice. This method uses the Consistent Hashing algorithm, whose basic principle is as follows:

[0060] ① Ring-shaped Hash Space: The hash value range is abstracted as a ring-shaped space (usually an integer scale ring from 0 to 2 32 -1). The ID value of the sending node is mapped to a certain position on the ring by a hash function.

[0061] ② Data Mapping Rule: For a certain data key Key, find the nearest frequency domain slice sequence number clockwise along the integer scale ring.

[0062] Step-by-step analysis of the Consistent Hashing algorithm:

[0063] ① Hash Function Selection: Common hash functions include MD5, SHA-1, FNV Hash, etc., which need to ensure uniform distribution of hash values.

[0064] ②Node mapping to ring: for each node, calculate the hash value according to the ID, and map to the corresponding position on the ring.

[0065] ③Data mapping to node: calculate the hash value for the data key, and find the nearest node along the ring clockwise,

[0066] Determine the home frequency domain slice sequence number.

[0067] A plurality of sending nodes map the nodes to M available frequency domain slices using a consistent hash algorithm according to their own identity ID in a contention period. Each sending node sends a packet request (RTS) outwards in the time slot request time slice of the corresponding frequency domain slice RC i When a plurality of nodes in the network have the need to send data, they can send packet requests (RTS) according to their time slot state list in the same contention period by selecting the frequency domain slice corresponding to the node.

[0068] The M frequency domain slice resources do not interfere with each other in the frequency domain, and all different receiving nodes can detect multiple packet requests in parallel, and filter out the packet requests sent to themselves according to the destination address of the packet request. After the target receiving node of the packet request receives the packet request, it generates a packet response CTS according to the time slot state list, and sends it out in the time slot response time slice by broadcast. After all the neighboring nodes around the receiving node receive the CTS packet response, they re-arrange their transmission time and update their time slot state list.

[0069] The content of the packet request includes the source address, the destination address, the frequency domain slice sequence number occupied by the sending node, the information frame sequence number of the data transmission reservation, the data transmission priority and the data transmission frequency band; wherein, the neighboring nodes of the sending node receive the packet request, and judge whether it is the target receiving node based on the destination address in the packet request.

[0070] Specifically, a sending node can select its new transmission time slot based on the transmission time arrangement information broadcasted by all its one-hop neighboring nodes in the last superframe. The sending node reserves an information frame in the user information time arrangement reservation information time slot according to its transmission requirements (such as single target receiving node transmission, multi-target receiving node transmission, broadcast transmission). If there are multiple time slots that meet the transmission requirements, the sending node randomly selects one of them to arrange the reservation information frame.

[0071] When the network layer has data to send, the sending node selects a frequency domain slice to initiate a reservation information frame request service in the contention period, preliminarily arranges the time according to the node time slot state list, encapsulates the arrangement into a packet request, and then broadcasts the packet request in the time slot request time slice, and waits for the packet response sent back by the target receiving node of the packet request.

[0072] Step S3, the target receiving node confirms the information frame reserved by the sending node based on its own time slot state list, and sends a group response in the time slot response time slice corresponding to the frequency domain slice, while updating its own time slot state list; the sending node receives the response in the time slot response time slice and updates its own time slot state list.

[0073] The group response content includes the source address and destination address of the data sent by the target receiving node, a response code, allowed reserved information frame serial numbers, data transmission priority, and data transmission frequency band; wherein the sending node formally confirms the group request sent by it based on the allowed reserved information frame serial numbers in the received response.

[0074] Each target receiving node generates a response according to the data transmission priority and reserved information frame serial numbers in the group request sent by each sending node; the response content includes a time slot request allowed response, a time slot request partially allowed response, a time slot request rejected response, or a time slot request conflict response.

[0075] The target receiving node confirms whether the information frame reserved by the sending node is allowed to be received by itself based on the time slot state list; if all the reserved information frames are allowed to be received by itself, the response content is a time slot request allowed response; if some of the reserved information frames are allowed to be received by itself, the response content is a time slot request partially allowed response; if none of the reserved information frames is allowed to be received by itself, the response content is a time slot request rejected response; if there are multiple source addresses of the reserved information frames from the same frequency domain slice in the same reserved frame, the response content is a time slot request conflict response.

[0076] Specifically, after receiving the group request, the receiving node confirms the time slot request proposed in the group request sent to itself according to its own time slot state list and the group request broadcasted by each sending node in the time slot request time slice in step S2.

[0077] If no time slot request group request is received, no response will be made.

[0078] Each sending node updates the time slot state list according to the response sent by its target receiving node, including:

[0079] If the response code is a time slot request allowed response, the time slot state list is updated according to the content of the sent group request and a broadcast is sent;

[0080] If the response code is a time slot request partially allowed response, the time slot state list is updated according to the allowed reserved information frame serial numbers and a broadcast is sent, while the network layer is notified that this time sending group request is partially allowed, and the sending node waits for the next superframe to resend the sending group request for the part not sent;

[0081] If the response code is time slot request rejection response, updating the time slot state list content includes sending packet request reservation information frame failure and issuing a broadcast, while informing the network layer of the failure of this packet request, waiting for the next superframe to reissue the packet request;

[0082] If the response code is time slot request conflict response, updating the time slot state list content includes decoding the packet request failure and issuing a broadcast, while informing the network layer of the failure of this packet request, waiting for the subsequent superframe to reissue the packet request;

[0083] If no response code is received within the specified time, updating the time slot state list content includes this packet request encountering a collision and issuing a broadcast, waiting for the next superframe to reissue the packet request.

[0084] Specifically, the sending node processes the packet response (CTS) returned by its target receiving node:

[0085] a) If a time slot request permission response is received, the time schedule preliminarily made before is formally determined, the time slot state list is updated, and the update is broadcast in the broadcast time slice, and this time slot request is successfully completed;

[0086] b) If a time slot request partial permission response is received, the time schedule is re-made according to the permitted part, the time slot state list is updated, the update is broadcast in the broadcast time slice, and then the network layer is informed that this time slot request can only be partially satisfied;

[0087] c) If it is a time slot request rejection response, the time slot state list still needs to be updated, the updated time slot state list is broadcast in the broadcast time slice, and then the network layer is informed that this time slot request has completely failed, and the time slot request operation is ended;

[0088] d) If no packet response returned by the target receiving node is received within the specified time, it is considered that this time slot request encounters a collision and fails, the time slot state list still needs to be updated, the update is broadcast in the broadcast time slice, and the time slot request is re-performed in the next superframe.

[0089] If multiple sending nodes receive a response code of time slot request conflict response, each sending node retreats to a different subsequent superframe according to the data transmission priority to re-send the packet request.

[0090] Specifically, if there are many nodes in the network that have data sending requirements at the same time, the receiving node detects multiple packet requests of sending nodes on the same frequency domain slice of the same contention period, and these packet requests overlap in time domain and frequency domain, which will interfere with each other and cause the receiving node to fail to correctly decode. The receiving node will generate a report of the conflicting packet response, and the corresponding multiple sending nodes will update their time slot state lists after receiving the packet response and back off to the next contention period to re-arrange their transmission time.

[0091] Step S4, the sending node and the target receiving node broadcast the updated time slot state list in the broadcast time slice.

[0092] If the information of a node in the time slot state list is not updated for more than a preset number of superframes, the remaining nodes will delete the content of the time slot state list when updating the time slot state list.

[0093] Specifically, the receiving node adjusts its transmission time arrangement based on the received information of the transmission time arrangement of the adjacent nodes each time it receives the information, and updates its time slot state list. If the information of a certain adjacent node in the time slot state list has not been updated for a period of time, the node is considered to have been disconnected from the network, and its content is deleted in the broadcast time slice.

[0094] Step S5, the sending node and the target receiving node transmit and receive data according to the reserved information frames.

[0095] The sending node and the target receiving node transmit and receive data according to the reserved information frames, including: in the plurality of information frames, each sending node transmits data according to the data transmission frequency band determined by the sending packet request and the packet response and the reserved information frame; and the target receiving node receives and processes the information sent by the corresponding sending node in the determined data transmission frequency band and the reserved information frame.

[0096] In the user information period, the nodes in the network determine their transmission and reception states according to their time slot state lists. When the allocated time slot in the contention period arrives, the sending node transmits information in the manner agreed by the sending packet and the response packet; the receiving node switches to the receiving state in the corresponding time slot, and receives information in the manner agreed by the sending packet and the response packet.

[0097] It should be noted that the steps S2-S5 are cyclically performed for multi-node ad hoc network data transmission and reception.

[0098] The above process will be described in the form of a specific example.

[0099] In one embodiment of the present application, there are 8 nodes in the wireless self-organizing network, the system operating bandwidth is 8M, the contention period divides the operating bandwidth into 4 frequency domain slices in the frequency domain, each frequency domain slice occupies 2M bandwidth, and there is a protection interval bandwidth of 0.2M between each frequency domain slice. As shown in Table 1. The data transmission in the information period occupies the entire 8M operating bandwidth in the frequency domain, and is completed according to the time slot negotiated in the contention period in the time domain.

[0100] Table 1

[0101]

[0102] As shown in Table 1, in a self-organizing network consisting of 8 nodes, node 2 plans to send a group of data to node 3 in the information period, and the operation process of the protocol is as follows:

[0103] ① Node 2 has the demand to send data to node 3, and the pre-scheduling time is calculated to approximately occupy 4 information frames, and according to the node time slot state list, information period IF1-4 is selected to transmit user data;

[0104] ② Use the sending node ID to map node 2 to the frequency domain slice RC i

[0105] by using the consistency hash algorithm;

[0106] ③ Node 2 sends a packet request in the time slot request time slice of the contention period frequency domain slice RC i , and the packet content includes the source address, the destination address, the frequency domain slice serial number, the reserved information frame serial number (IF

[0107] serial number), the data transmission priority, etc.;

[0108] ④ The neighbor nodes 1 and 3 of node 2 are in a receiving state at the time slot request time slice;

[0109] a) Node 1 receives the packet request and parses the packet content, judges that the data is not sent to itself according to the destination address, and directly discards the packet;

[0110] b) Node 3 receives the packet request and parses the packet content, judges that the data is sent to itself according to the destination address, and queries the time slot state list of itself to confirm that node 2 requests to occupy the information period IF 1-4 (the reserved information frame serial number);

[0111] ⑤ Node 3 completely approves the time slot request of node 2, generates a packet response, and sends the response packet in the time slot response time slice of the frequency domain slice RC i , and the packet content includes the source address, the destination address, the response code, the occupied information period IF serial number, the transmission priority, etc.;

[0112] (6) Node 2 and node 4 are in the receiving state at the time slot response time slice;

[0113] a) Node 2 parses the packet response content, and formally confirms the time slot request made before;

[0114] b) Node 4 parses the packet response content, and directly discards the packet according to the destination address;

[0115] (7) Node 2 and node 3 broadcast the updated time slot state list in the frequency domain slice RC i broadcast time slice;

[0116] (8) Node 1 is a neighbor of node 2, and node 4 is a neighbor of node 3, and receives the broadcast of the time slot state list in the update broadcast time slice of the frequency domain slice RC i , and updates the time slot state list according to the content received by the broadcast;

[0117] (9) In the user information period, node 2 sends data according to the frequency and IF number negotiated by the packet request and the packet response; node 3 switches to the receiving state on the negotiated frequency band and information frame, receives and processes the information frame sent by node 2; node 1 is in the idle state according to the time slot state list, and does not need to do anything.

[0118] Another specific example of the application is shown in Table 1, in a self-organizing network consisting of 8 nodes, node 6 plans to send a set of data to node 5 in the information period, and node 8 plans to send a set of data to node 7 in the information period, and the operation process of the protocol is as follows:

[0119] (1) Node 6 has the demand to send data to node 5, and calculates that about 3 information frames are needed to be occupied during pre-scheduling, and selects IF 1-3 to transmit user data according to the node time slot state list; node 8 has the demand to send data to node 7, and calculates that about 3 information frames are needed to be occupied during pre-scheduling, and selects IF 3-5 to transmit user data according to the node time slot state list; (2) using node ID to map node 6 to RC j resources through a consistent hash algorithm, and mapping node 8 to RC k resources;

[0120] (3) Node 6 sends a packet request RTS in the time slot request time slice of the frequency domain slice RC j in the contention period,

[0121] Node 8 sends a packet request RTS in the time slot request time slice of the frequency domain slice RC k in the contention period; the packet content includes the source address, the destination address, the RC resource number corresponding to the frequency domain slice, the information frame number (IF number) occupied in the information period, and the transmission priority.

[0122] IV. The neighbor nodes 5 and 7 of the node 6 and the node 8 are in the receiving state at the time slot request time slice; a) The node 5 receives the packet request and analyzes the packet content, judges according to the destination address that the data is sent to itself, and queries the information frame number (IF number) of the information period occupied by the node 6 according to the time slot state list;

[0123] b) The node 7 receives the RTS request packets of the node 6 and the node 8 at the same time, analyzes the packet content, and according to the destination address, the occupied information period IF number, and the transmission priority of the two packet requests, queries the information frame number (IF number) of the information period occupied by the node 8 according to the time slot state list;

[0124] V. The node 5 fully approves the time slot request of the node 6, generates a packet response, and sends it at the time slot response time slice of the frequency domain slice RC j , and the packet content includes the source address, the destination address, the response code, the occupied information frame number (IF number 1-3), the transmission priority, etc.

[0125] VI. The node 7 partially approves the time slot request of the node 8, generates a packet response, and sends it at the time slot response time slice of the frequency domain slice RC k , and the packet content includes the source address, the destination address, the response code, the occupied information period IF number 4-5, the transmission priority, etc.

[0126] VII. The node 4, the node 6, and the node 8 are in the receiving state at the time slot response time slice;

[0127] a) The node 4 analyzes the packet response content, judges according to the destination address that it is not sent to itself, and directly discards the packet;

[0128] b) The node 6 analyzes the packet response content, and according to the time slot request made before the packet response of the node 5 is officially confirmed;

[0129] c) The node 8 analyzes the packet response content, according to the partial confirmation of the time slot request made before the packet response of the node 7, and according to the time slot resources confirmed by negotiation, re-sends the pre-schedule of the data (updates the time slot state list);

[0130] VIII. The node 5 and the node 6 broadcast their updated time slot state lists at the broadcast time slice of the frequency domain slice RC j , and the node 7 and the node 8 broadcast their updated time slot state lists at the broadcast time slice of the frequency domain slice RC k ;

[0131] IX. The node 4, as a neighbor of the node 5, will receive the broadcast of the time slot state list at the broadcast time slice of the frequency domain slice RC j , and updates its own time slot state list according to the content received by the broadcast;

[0132] d) User information period,

[0133] a) Node 6 sends data according to the agreed frequency band and the reserved information frame in the group request and group response, and node 5 switches to the receiving state on the agreed frequency band and information frame to receive and process the information frame sent by node 6;

[0134] b) Node 8 sends the rescheduled data according to the agreed frequency band and the reserved information frame in the group request and group response, and node 7 switches to the receiving state on the agreed frequency and the reserved information frame IF to receive and process the information frame sent by node 8;

[0135] c) Node 4 places itself in the Idle state according to the time slot state list and does not need to do anything.

[0136] Compared with the prior art, the embodiment provides a wireless channel link layer transmission control method which combines the advantages of TDMA and CSMA, and includes a reservation frame and multiple information frames; the reservation frame is divided into multiple frequency domain slices; each frequency domain slice sequentially includes a time slot request time slice, a time slot response time slice and a broadcast time slice; no frame interval is set between each time slice; multiple sending nodes can simultaneously send packet requests in the time slot request time slice of the reservation frame; multiple target receiving nodes can simultaneously send packet responses in the time slot response time slice of the reservation frame; the overhead of control frames is reduced, and the transmission efficiency of data is improved; an optimized resource allocation strategy is adopted to realize dynamic and flexible allocation of time slots, frequency bands and other resources, and improve the utilization rate of channel resources; thereby the overall performance of the link layer of the wireless self-organizing network is improved, and the practicability and reliability of the network are enhanced. The packet request content sent by the multiple sending nodes in the form of broadcast in the time slot request time slice includes the source address of the sending data, the destination address, the frequency domain slice sequence number occupied by the sending node, the information frame sequence number reserved for the sending data, the data transmission priority and the data transmission frequency band; wherein the neighbor nodes of the sending node judge whether they are target receiving nodes based on the destination address in the packet request. Each receiving node judges whether it is a target receiving node according to the destination address, and judges whether it can allow data reception in the reserved information frame sequence number according to the broadcast data transmission priority and the information frame sequence number reserved for the sending data. The time slot allocation certainty of TDMA and the dynamic and flexible access feature of CSMA are combined, which can not only avoid the waste of idle time slots caused by the fixed time slot allocation of the TDMA protocol, but also reduce the probability of data collision compared with the CSMA protocol in a multi-node and high-load environment, thereby optimizing the use efficiency of wireless resources. The technical scheme of the embodiment is based on local network information, and makes transmission time arrangement in a full-distributed, parallel and fast manner, reduces idle monitoring and retransmission conflicts, and can reduce the energy consumption of the entire communication system. The broadcast sending mechanism and the packet request content of the embodiment allow nodes to allocate the reserved information frames as transmission time slots when the network structure and bandwidth demand change. In the embodiment, the data transmission and reception of all nodes in the network remain accurate in time, so as to realize time slot synchronization in the entire network; the channel used by the wireless network is a wideband channel, and there can be multiple available channels for sending data in the information frame. The data transmission and reception of different frequency domain slices do not interfere with each other; the link between each pair of receiving and transmitting nodes is a symmetric channel, and the two nodes can normally communicate with each other without interference. During the operation of the protocol, the nodes can move but the topology changes slowly, and once a transmission time arrangement is calculated, the TDMA transmission time arrangement can be used for a period of time before the network topology changes force another transmission time arrangement (or update) to be made.

[0137] Those skilled in the art can understand that all or part of the processes of the above-mentioned embodiment methods can be completed by instructing the relevant hardware by a computer program, and the program can be stored in a computer readable storage medium. The computer readable storage medium is a disk, an optical disk, a read-only memory, a random access memory, etc.

[0138] The above description is merely preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. An optimized wireless channel link layer transmission control method, characterized by, The application relates to a multi-node self-organizing network for transmitting data in superframes. The superframe comprises a reservation frame and a plurality of information frames in sequence, and the reservation frame comprises a plurality of frequency domain slices corresponding to the nodes; each frequency domain slice comprises a time slot request time slice, a time slot response time slice and a broadcast time slice in sequence. Each sending node sends a packet request in the time slot request time slice of the corresponding frequency domain slice; the packet request comprises a reserved information frame selected according to a time slot state list of the sending node. A target receiving node confirms the information frame reserved by the sending node based on a time slot state list of the target receiving node, sends a packet response in the time slot response time slice of the corresponding frequency domain slice, and updates the time slot state list of the target receiving node. The sending node receives the response in the time slot response time slice and updates the time slot state list of the sending node. The sending node and the target receiving node broadcast the updated time slot state list in the broadcast time slice. The sending node and the target receiving node send and receive data according to the reserved information frame. The content of the packet request comprises a source address, a destination address, a frequency domain slice serial number occupied by the sending node, a reserved information frame serial number, a data transmission priority and a data transmission frequency band; wherein a neighbor node of the sending node judges whether the neighbor node is the target receiving node based on the destination address in the packet request.

2. The wireless channel link layer transmission control method of claim 1, wherein, The content of the packet response comprises a source address, a destination address, a response code, an allowed reserved information frame serial number, a data transmission priority and a data transmission frequency band; wherein the sending node formally confirms the packet request sent by the sending node based on the allowed reserved information frame serial number in the received response.

3. The wireless channel link layer transmission control method of claim 2, wherein, Each target receiving node generates a response according to the data transmission priority and the reserved information frame serial number in the packet request sent by each sending node; the response content comprises a time slot request permission response, a time slot request partial permission response, a time slot request rejection response or a time slot request conflict response.

4. The wireless channel link layer transmission control method of claim 3, wherein, Wherein, the target receiving node confirms whether the information frame reserved by the sending node is allowed to be received by the target receiving node based on the time slot state list; if all the reserved information frames are allowed to be received by the target receiving node, the response content is the time slot request permission response; if part of the reserved information frames are allowed to be received by the target receiving node, the response content is the time slot request partial permission response; if none of the reserved information frames are allowed to be received by the target receiving node, the response content is the time slot request rejection response; if there are multiple source addresses of the reserved information frames from the same frequency domain slice in the same reservation frame, the response content is the time slot request conflict response. Each sending node updates the time slot state list according to the response sent by the target receiving node, comprising:

5. The wireless channel link layer transmission control method of claim 4, wherein, if the response code is the time slot request permission response, updating the time slot state list according to the content of the sent packet request and sending a broadcast; if the response code is the time slot request partial permission response, updating the time slot state list of the sending node according to the allowed reserved information frame serial number and sending a broadcast, and informing the network layer that the current sent packet request is partially allowed, and waiting for the next superframe to resend the sending packet request for the unsent part. ​ If the response code is time slot request rejection response, updating the time slot state list content includes sending packet request reservation information frame failure and issuing a broadcast, while informing the network layer of the failure of this packet request, waiting for the next superframe to resend the packet request; If the response code is time slot request conflict response, updating the time slot state list content includes decoding the packet request failure and issuing a broadcast, while informing the network layer of the failure of this packet request, waiting for the subsequent superframe to resend the packet request; If no response code is received within the specified time, updating the time slot state list content includes this packet request encountering a collision and issuing a broadcast, waiting for the next superframe to resend the packet request.

6. The wireless channel link layer transmission control method of claim 1, wherein, Each sending node identity code is mapped to the corresponding frequency domain slice through a hash algorithm.

7. The wireless channel link layer transmission control method of claim 1, wherein, The bandwidths of the plurality of frequency domain slices are equal, and a guard interval is left between each frequency domain slice.

8. The wireless channel link layer transmission control method of claim 1, wherein, The sending nodes and the target receiving node send and receive data according to the reserved information frames, including: in the plurality of information frames, each sending node will send data according to the data transmission frequency band determined by the packet request and the packet response, and the reserved information frames; the target receiving node receives and processes the information sent by the corresponding sending node in the determined data transmission frequency band and the reserved information frames.

9. The wireless channel link layer transmission control method of claim 1, wherein, If the information of a node in the time slot state list is not updated for more than a preset number of superframes, the contents of the time slot state list of the remaining nodes are deleted when updating the time slot state list.

10. The wireless channel link layer transmission control method of claim 5, wherein, If multiple sending nodes receive a response code of time slot request conflict response, each sending node backs off to a different subsequent superframe according to the data transmission priority to resend the packet request.

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