Low-delay co-transmission communication method for narrowband satellite Internet of Things

Abstract

The invention belongs to the technical field of wireless ad hoc networks, and discloses a narrow-band satellite Internet of Things-oriented low-delay co-transmission communication method, which comprises the following steps of: randomly deploying M ground nodes in an area A, and initializing the current local data size Di of each ground node; in each unit time, M ground nodes are traversed repeatedly, a ground node i which has the largest current local data, is idle and is not selected is selected as a sending node i, and a corresponding receiving node j is determined, so that the sending node which has data and is idle can be diverged outwards as far as possible to search for nodes for data transmission. Therefore, more nodes on the ground can obtain the data so as to carry out uplink data transmission. Meanwhile, through a reasonable data transmission strategy, the priority of uplink data transmission is the highest, ground data is transmitted to a satellite as soon as possible, ground nodes can participate in cooperative data transmission step by step, and finally the whole data transmission task is completed with small time delay.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless ad hoc networks, and more specifically, relates to a low-latency cooperative transmission communication method for narrowband satellite Internet of Things. Background Art

[0002] As a key solution for realizing Internet of Things connections globally, the Satellite Internet of Things (SIoT) plays an important role in the emergency information backhaul in network environments with poor conditions such as relatively remote areas or complex terrains. In this scenario, ground nodes need to transmit ground data to satellites in a timely manner for processing. Since the uplink transmission bandwidth of a single ground node is limited, its uplink transmission delay is often large. For this reason, people often utilize surrounding idle ground nodes. By quickly distributing data to them and then using their idle uplink transmission bandwidth for cooperative transmission, the entire data transmission task can be completed with a relatively small delay.

[0003] Considering the half-duplex transmission characteristics of nodes and limitations such as link capacity, designing a reasonable data distribution method will involve two aspects: First, the algorithm needs to reasonably schedule the transceiver behavior of nodes to maximize the bandwidth utilization rate of nodes to obtain cooperative transmission data, so as to participate in uplink data transmission as much as possible. Second, design a suitable uplink transmission strategy so that ground data can be transmitted to satellites as soon as possible.

[0004] Regarding the scheduling of transceiver nodes, existing research mainly relies on link quality and energy consumption considerations to select receiving nodes, which may lead to problems such as load imbalance and energy consumption imbalance, thereby affecting data transmission delay. Regarding the design of uplink transmission strategies, existing research mostly considers physical layer cooperative fusion, and generally requires unified scheduling of uplinks by ground nodes, which will cause risks such as scheduling delay and data congestion. Summary of the Invention

[0005] Aiming at the above defects or improvement requirements of the existing technology, the present invention provides a low-latency cooperative transmission communication method for narrowband satellite Internet of Things, and its purpose is to complete the uplink transmission task of ground nodes with a relatively low delay.

[0006] To achieve the above purpose, the present invention provides a low-latency cooperative transmission communication method for narrowband satellite Internet of Things, including:

[0007] Step 1: Randomly deploy M ground nodes in area A, initialize the current local data D of one ground node i i with a size of P, and the current local data sizes of other ground nodes are 0. Initialize the status of each ground node as idle and not selected; where P is the initial data to be transmitted, i ∈ {1, 2,..., M}, and M > 1;

[0008] Step 2: Within the current unit of time, traverse the M ground nodes, select the ground node i with the largest current local data that is idle and has not been selected as the sending node i, and determine the corresponding receiving node j; where the receiving node j is one of the ground nodes and i ≠ j;

[0009] Step 3: When D i ≤ T, update the status of the sending node i to selected and jump to Step 4; when T < D i < T + C i,j , the sending node i transmits data of size T to the satellite and data of size D i - T to the receiving node j, and then update D i = 0, and set the status of both the ground nodes i and j to busy; at the same time, judge the receiving node j: if (D i - T) + D j < T, the receiving node j transmits the current local data (D i - T) + D j to the satellite, and then update D j = 0; if (D i - T) + D j ≥ T, the receiving node j transmits data of size T to the satellite, and then update D j = D j +(D i - T) - T; where T is the set size of the uplink transmission rate and C i,j is the size of the ground link capacity between the ground nodes i and j;

[0010] Step 4: Loop and execute Step 2 and Step 3 until there is no selectable sending node i within the current unit of time; or until all the idle ground nodes i among the M ground nodes satisfy D i ≤ T. At this time, the idle ground nodes i that satisfy D i ≤ T directly transmit data D i to the satellite, and then update D i = 0;

[0011] Step 5: Update the status of all M ground nodes to idle and not selected, and take the next unit of time as the current unit of time. Loop and execute Step 2 to Step 4 until the local data of all ground nodes is 0. At this time, all the initial data P to be transmitted is uploaded to the satellite.

[0012] Furthermore, in Step 3, it also includes: when D i ≥ T + C i,j , the sending node i transmits data of size T to the satellite and data of size C i,j to the receiving node j, and then update D i= D i -(T + C i,j ); The receiving node j transmits data of size T to the satellite and then updates D j = D j + C i,j - T, and sets the states of ground nodes i and j to busy.

[0013] Furthermore, in step 2, determining the receiving node j corresponding to the sending node i includes:

[0014] Calculating the probability f that each idle ground node j that can communicate with the sending node i becomes the receiving node j , and selecting the ground node j with the maximum probability f j as the receiving node j.

[0015] Furthermore, in step 3, when T < D i < T + C i,j and D i ≥ T + C i,j , after the sending node i transmits data to the satellite and the receiving node j, it also includes: incrementing by 1 the number of times that ground nodes i and j have been selected as transceiver nodes;

[0016] The calculation method of the probability f j is as follows:

[0017]

[0018] where k 1 , k 2 , k 3 represent random coefficients; f 1 is inversely proportional to D i ; f 2 is inversely proportional to the number of times the ground node j has been selected as a transceiver node; f 3 is inversely proportional to d i,j , and d i,j represents the distance d i,j between the ground node j and the sending node i.

[0019] Furthermore, the hardware devices of the M ground nodes are the same.

[0020] Furthermore, if ground nodes i and j communicate, then both ground nodes i and j are in the busy state, otherwise they are in the idle state; among them, if the Euclidean distance d i,j between ground nodes i and j ≤ R, then the two nodes can communicate, and R is the communication range of each ground node.

[0021] The present invention also provides a low-latency cooperative transmission communication system for narrowband satellite Internet of Things, including a computer-readable storage medium and a processor;

[0022] The computer-readable storage medium is used to store executable instructions;

[0023] The processor is used to read the executable instructions stored in the computer-readable storage medium and execute the low-latency cooperative transmission communication method for narrowband satellite Internet of Things described in any one of the above.

[0024] The present invention also provides a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, it implements the low-latency cooperative transmission communication method for narrowband satellite Internet of Things described in any one of the above.

[0025] The present invention also provides a computer program product, including a computer program, and when the computer program runs on a computer, it enables the computer to execute the low-latency cooperative transmission communication method for narrowband satellite Internet of Things described in any one of the above.

[0026] Generally speaking, through the above technical solutions conceived by the present invention, the following beneficial effects can be achieved:

[0027] (1) The present invention provides an efficient cooperative transmission communication method, and obtains a smaller overall transmission delay by reasonably distributing data in ground nodes. Specifically, in terms of the design of the uplink transmission strategy, the present invention provides a method based on the highest priority of uplink transmission, that is, when a ground node transmits data, it first considers transmitting the data to the satellite. When there is excess data at the ground node, it then transmits it to other ground nodes. It is a cooperative communication method based on the physical layer. Specifically, for the current sending node i and receiving node j, when the current local data size D i does not exceed the set uplink transmission rate size T, the data is directly transmitted to the satellite; and when T < D i < T + C i,j at the same time, the current local data is transmitted to the receiving node j and the satellite, and the receiving node also assists the sending node to distribute all or part of the current local data to the satellite according to this priority, so that the data can be transmitted to the satellite as soon as possible. The cooperative transmission communication method based on the physical layer of the present invention can immediately perform uplink transmission as long as the node has data, without waiting for the scheduling period, which can greatly reduce the data delay and ensure that the data will not accumulate on the ground for a long time, reducing risks such as data congestion.

[0028] (2) Further, when D i ≥ T + C i,jWhen the time comes, the sending node i simultaneously transmits the current local data to the receiving node j and the satellite. The receiving node j assists the sending node i in uploading part of the data to the satellite without waiting for the scheduling period. The uplink data transmission has the highest priority to ensure that the data can be transmitted to the satellite as soon as possible in various scenarios.

[0029] (3) Further, regarding the scheduling of the transceiver nodes, the calculation method of the probability f of determining the receiving node designed in the present invention innovatively proposes the concept of the historical selection times, and takes the number of times being selected as the transceiver node in history as an important influencing factor to participate in the determination of the receiving node, which helps to prevent some nodes from being overused, thereby improving the overall fairness and long-term stability of the system; at the same time, combining the local data volume and distance conditions, it is ensured that the sending nodes with data and idle can diverge as much as possible to find nodes for data transmission, so that more ground nodes can obtain data for uplink data transmission. In this way, the link quality and efficiency can be better guaranteed, and the data transmission delay can be further reduced. j The calculation method of determines the receiving node probability f, innovatively proposes the concept of historical selection times, takes the number of times being selected as the transceiver node in history as an important influencing factor to participate in the determination of the receiving node, which helps to prevent some nodes from being overused, thereby improving the overall fairness and long-term stability of the system; at the same time, combining the local data volume and distance conditions, it is ensured that the sending nodes with data and idle can diverge as much as possible to find nodes for data transmission, so that more ground nodes can obtain data for uplink data transmission. In this way, the link quality and efficiency can be better guaranteed, and the data transmission delay can be further reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a flowchart of the low-latency cooperative transmission communication method for narrowband satellite Internet of Things in the embodiment of the present invention;

[0031] Figure 2 is a schematic diagram of ground node data distribution in the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0033] Embodiment 1

[0034] As Figure 1 shown, the embodiment of the present invention provides a low-latency cooperative transmission communication method for narrowband satellite Internet of Things, including:

[0035] Step 1: Randomly deploy M ground nodes in area A, where M > 1; in the embodiment of the present invention, the hardware devices of the M ground nodes are the same; area A is generally a relatively remote area or a complex terrain area with a poor network environment. Arbitrarily select one of the M ground nodes as node 1, initialize the local data size of node 1 to P (P > 0), where P is the initial data to be transmitted, and initialize the local data of other ground nodes to 0; D iis the current local data size of the ground node i (i ∈ {1, 2, …, M}). At the initial moment, when i = 1, D i = P; T is the uplink transmission bandwidth size of the M ground nodes, that is, the set uplink transmission rate size; C i,j is the ground link capacity size between the ground nodes i and j (i, j ∈ {1, 2, …, M}, and i ≠ j) (C i,j >> P), which is calculated by Shannon's theorem. Each ground node has its own communication range R. In the embodiments of the present invention, the communication ranges of the M ground nodes are the same; if the Euclidean distance d i,j between the ground nodes i and j > R, the two nodes cannot communicate, otherwise they can communicate. At the same time, if the ground node i communicates with the ground node j, both the ground nodes i and j are in a busy state, otherwise they are in an idle state. Initialize the states of each ground node to idle and not selected; where not selected means that the node has not been selected as the current sending node within the current unit time.

[0036] Step 2: Within the current unit time, traverse the M ground nodes, and select the ground node with the largest current local data, idle and not selected as the current sending node i; where selecting a ground node that has not been selected avoids always selecting the same ground node as the current sending node every time when D i ≤ T in Step 3; calculate the probability f j that each idle ground node j that can communicate with the current sending node i becomes the current receiving node;

[0037] Preferably, in the embodiments of the present invention, a calculation method for determining the probability f j of the receiving node is provided, and its calculation formula is:

[0038]

[0039] where k 1 , k 2 , k 3 represent random coefficients, which are empirical values and are determined through experiments in the embodiments of the present invention; f 1 is inversely proportional to D j , the smaller D j , the larger f 1 ; f 2 is inversely proportional to the number of times the ground node j has been selected as a transceiver node. The fewer the number of times it has been selected, the larger f 2 ; f 3 is inversely proportional to d i,j , d i,j represents the distance d i,j size between the ground node j and the sending node i, di,j The smaller, the f 3 The larger. In other embodiments, other calculation methods may also be selected to calculate the probability f j .

[0040] Select the ground node j with the highest probability in {f j} as the receiving node of the sending node i.

[0041] Step 3: After selecting the current sending node i and receiving node j, data transmission is performed according to the following rules: (1) If D i ≤T, update the status of the sending node i to selected and jump to Step 4; (2) If T<D i <T + C i,j , the sending node i transmits data of size T to the satellite and data of size D i -T to the receiving node j, then set the current local data D i to 0, and increment the number of times the ground nodes i and j have been selected as transceiver nodes by 1, and set the status of the ground nodes i and j to busy and selected. In this case, the receiving node j also needs to be judged: ① If (D i -T)+D j <T, the receiving node j transmits all the current local data of size (D i -T)+D j to the satellite, then set the current local data D j to 0; ② If (D i -T)+D j ≥T, the receiving node j transmits data of size T to the satellite, then update the local data D j size to D j = D j +(C i -T)-T. (3) If D i ≥T + C i,j , the sending node i transmits data of size T to the satellite and data of size C i,j to the receiving node j, then update the current local data size to D i = D i -(T + C i,j ); the receiving node j transmits data of size T to the satellite, then update the current local data size to D j = D j +C i,j -T. And increment the number of times the ground nodes i and j have been selected as transceiver nodes by 1, and set the status of the ground nodes i and j to busy and selected.

[0042] Step 4: Execute steps 2 and 3 repeatedly until there is no selectable sending node in the current unit time, or the idle ground nodes i (regardless of whether they have been selected) among the M ground nodes all satisfy D i ≤T, the current iteration ends. If all idle ground nodes i among the M ground nodes satisfy D i ≤T, then directly transmit the data size D to the satellite i , and then D i =0.

[0043] Step 5: Update the status of all M ground nodes to idle and unselected, and use the next unit time as the current unit time, and repeat steps 2 to 4 until the local data of all ground nodes is 0 at a certain moment. At this time, all the initial data P to be transmitted are transmitted to the satellite, completing the entire data transmission task.

[0044] like Figure 2 As shown, it is a schematic diagram of ground node data distribution in an embodiment of the present invention, with 11 ground nodes randomly deployed in rectangular area A. Assume that P is 100Mbit, T is 10^5bit / s, and the ground link capacity is obtained by Shannon's calculation formula. According to the cooperative communication method designed in the embodiment of the present invention, idle sending nodes with data can diverge outward as much as possible to find nodes for data transmission, so that more nodes on the ground can obtain data for uplink data transmission. At the same time, through a reasonable data transmission strategy, the uplink data transmission has the highest priority, so that the ground data can be transmitted to the satellite as soon as possible. Figure 2 As shown, according to the steps of this method, the ground nodes can gradually participate in the collaborative data transmission and finally complete the entire data transmission task with a smaller delay.

[0045] The present invention provides an efficient cooperative communication method, which obtains a smaller overall transmission delay by reasonably distributing data in ground nodes. In terms of uplink transmission strategy design, the present invention provides a method based on the highest priority of uplink transmission, that is, when the ground node transmits data, it gives priority to transmitting data to the satellite. When there is excess data in the ground node, it transmits it to other ground nodes. This is a cooperative communication method based on the physical layer. Specifically, for the current sending node i and receiving node j, the current local data size D i When the uplink transmission rate does not exceed the set value T, the data is directly transmitted to the satellite; when D iWhen it is ≥T, the current local data is simultaneously transmitted to the receiving node j and the satellite, and the receiving node also assists the sending node to distribute all or part of the current local data to the satellite according to this priority, so that the data can be transmitted to the satellite as soon as possible. In the co - transmission communication method based on the physical layer of the present invention, as long as the node has data, it immediately performs uplink transmission without waiting for the scheduling period, which can greatly reduce data delay and ensure that the data will not accumulate on the ground for a long time, reducing risks such as data congestion.

[0046] Furthermore, regarding the scheduling of the transceiver nodes, the calculation method for determining the probability f of the receiving node proposed innovatively by the present invention introduces the concept of the historical selection times, taking the number of times being selected as the transceiver node in history as an important influencing factor to participate in the determination of the receiving node, which helps to prevent some nodes from being over - used, thereby improving the overall fairness and long - term stability of the system; at the same time, combining the local data volume and distance conditions can better ensure the link quality and efficiency, and further reduce the data transmission delay. j In the low - latency co - transmission communication method for narrow - band satellite Internet of Things provided in the embodiments of the present invention, by reasonably designing and coordinating the transceiver behavior and transmission priority of the nodes, the uplink transmission task of the ground nodes is completed with low latency.

[0047] In the embodiment 2 of the present invention, a low - latency co - transmission communication system for narrow - band satellite Internet of Things is provided, including a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the steps of the low - latency co - transmission communication method for narrow - band satellite Internet of Things in the above - mentioned embodiment 1.

[0048] Embodiment 2

[0049] The relevant technical solutions are the same as above and will not be elaborated here.

[0050] The relevant technical solutions are the same as above and will not be elaborated here.

[0051] Embodiment 3

[0052] The embodiment of the present invention provides a computer - readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it implements the steps of the low - latency co - transmission communication method for narrow - band satellite Internet of Things in the above - mentioned embodiment 1.

[0053] Specifically, the memory may include a high - speed random - access memory, and may also include a non - volatile memory, such as a hard disk, a memory, a plug - in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, at least one magnetic disk storage device, a flash memory device, or other volatile solid - state storage devices.

[0054] The relevant technical solutions are the same as above and will not be elaborated here.

[0055] Example 4

[0056] An embodiment of the present application provides a computer program product, including a computer program. When the computer program runs on a computer, it causes the computer to execute the steps of the low-latency cooperative transmission communication method for narrowband satellite Internet of Things in Embodiment 1 above.

[0057] The related technical solutions are the same as above and will not be elaborated here.

[0058] Those skilled in the art can easily understand that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A low-latency cooperative communication method for narrowband satellite Internet of Things, characterized in that: include: Step 1: Randomly deploy M ground nodes in area A and initialize the current local data D of one of the ground nodes i i The size is P, the current local data size of other ground nodes is 0, and the status of each ground node is initialized to be idle and unselected; where P is the initial data to be transmitted, i∈{1, 2, …, M}, M>1; Step 2: In the current unit time, traverse M ground nodes, select the ground node i with the largest current local data, idle and unselected as the sending node i, and determine the corresponding receiving node j; where the receiving node j is one of the ground nodes, and i≠j; Step 3: D i When D ≤ T, update the status of the sending node i as selected and jump to Step 4; when T < D i < T + C i,j At this time, the sending node i transmits data of size T to the satellite and data of size D i - T to the receiving node j, and then update D i = 0, and set the status of the ground nodes i and j to busy; at the same time, judge the receiving node j: if (D i - T) + D j < T, the receiving node j transmits the current local data (D i - T) + D j to the satellite, and then update D j = 0; if (D i - T) + D j ≥ T, the receiving node j transmits data of size T to the satellite, and then update D j = D j + (D i - T) - T; where T is the set size of the uplink transmission rate, and C i,j is the ground link capacity between the ground nodes i and j; Step 4: Execute steps 2 and 3 repeatedly until there is no optional sending node i in the current unit time; or until all idle ground nodes i among the M ground nodes satisfy D i ≤T, then D is satisfied i Idle ground nodes i with a value less than T directly transmit data D to the satellite i , and then update D i =0; Step 5: Update the status of all M ground nodes to idle and unselected, and use the next unit time as the current unit time, and repeat steps 2 to 4 until the local data of all ground nodes is 0. At this time, all the initial data P to be transmitted are uploaded to the satellite.

2. The low-latency cooperative communication method according to claim 1, characterized in that: In step 3, also include: D i ≥T+C i,j When the sending node i transmits data of size T to the satellite, and transmits data of size C to the receiving node j i,j , and then update D i =D i -(T+C i,j ); The receiving node j transmits data of size T to the satellite, and then updates D j =D j +C i,j -T, and set the status of ground nodes i and j to busy.

3. The low-latency cooperative communication method according to claim 2, characterized in that: In step 2, the receiving node j corresponding to the sending node i is determined, including: Calculate the probability f that each idle ground node j that can communicate with the sending node i becomes a receiving node j , select probability f j The largest ground node j serves as the receiving node j.

4. The low-latency cooperative communication method according to claim 3, characterized in that: In step 3, T <D i <T+C i,j and D i ≥T+C i,j When the sending node i transmits data to the satellite and the receiving node j, it also includes: adding 1 to the number of times that the ground nodes i and j are selected as the sending and receiving nodes; The probability f j The calculation method is: Among them, k1, k2, k3 represent random coefficients; f1 and D j Inversely proportional; f2 is inversely proportional to the number of times ground node j has been selected as a transmitting and receiving node; f3 is inversely proportional to d i,j Inversely proportional, d i,j represents the distance d between ground node j and sending node i i,j size.

5. The low-latency cooperative communication method according to any one of claims 1 to 4, characterized in that: The hardware devices of the M ground nodes are the same.

6. The low-latency cooperative communication method according to claim 5, characterized in that: If ground nodes i and j communicate, then ground nodes i and j are both busy, otherwise they are idle. If the Euclidean distance d between ground nodes i and j is i,j ≤R, the two nodes can communicate, and R is the communication range of each ground node.

7. A low-latency cooperative transmission communication system for narrowband satellite Internet of Things, characterized in that: comprising a computer readable storage medium and a processor; The computer-readable storage medium is used to store executable instructions; The processor is used to read the executable instructions stored in the computer-readable storage medium to execute the low-latency cooperative communication method for narrowband satellite Internet of Things as described in any one of claims 1-6.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by the processor, the low-latency cooperative communication method for narrowband satellite Internet of Things is implemented as described in any one of claims 1-6.

9. A computer program product, characterized in that It includes a computer program, which, when running on a computer, enables the computer to execute the low-latency cooperative communication method for narrowband satellite Internet of Things as described in any one of claims 1-6.

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