A rate-aware network coding method and device based on instantly decodable network coding

Abstract

The present invention discloses a rate-aware network coding method and device based on instant decodable network coding, comprising: step (1) constructing a corresponding RA-IDNC coding relationship graph according to the link capacity from the base station to the user in the cell, the data packet information that the user needs to receive, and the RA-IDNC network coding condition; step (2) calculating the weights of all nodes corresponding to the user with the maximum initial completion time in the IDNC graph in the RA-IDNC coding relationship graph, selecting the node with the largest weight, and adding the node to the maximum weight group; step (3) retaining only the nodes with connecting edges with the selected maximum weight node in the RA-IDNC coding relationship graph, and updating the RA-IDNC coding relationship graph; step (4) if the node set in the updated RA-IDNC coding relationship graph is not an empty set, calculating the weights of all nodes and going to step (3); otherwise, outputting the maximum weight coding group.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless communications, and relates to a rate-aware network coding method and device based on instantly decodable network coding IDNC. Background Art

[0002] The concept of instantaneous decodable network coding (IDNC) was first proposed by D. Tmskov et al. Sorour et al. conducted in-depth research on IDNC and used binary XOR operation to implement IDNC coding, thereby eliminating the complex operation on the large Galois field required by RLNC. Similarly, this XOR coding performed at the transmitter only requires similar binary XOR decoding at the receiver, which can be decoded immediately to restore the original data packet. Compared with RLNC, it can achieve a smaller decoding delay and the decoding calculation complexity is much simpler. Moreover, no buffer is required at the receiver to store the encoded data packets. The next generation network is characterized by high data throughput, low latency, and high transmission reliability. Rate-aware network coding provides a potential technical approach to meet the above performance indicators. Most previous works optimize different parameters in systems based on instantaneous decodable network coding, consider the upper layer view of the network and abstract its physical layer conditions (e.g., fading, shadowing, etc.) into a simple erasure channel model, assuming that all coding packet combinations have the same physical layer data transmission rate, which does not conform to realistic channel conditions. As is known to all, different users in a cellular network experience different channel conditions, and therefore different data transmission rates may be provided by the base station. The differences in the coded data transmission rates will affect the selection of data packets to be combined in each transmission and the selection of the coded data transmission rate. The selection of the coded data packets and the selection of the coded data transmission rate need to be considered jointly to reduce the system data transmission completion time. Summary of the invention

[0003] Purpose: In order to overcome the deficiencies in the prior art, the present invention provides a rate-aware network coding method and device based on instantly decodable network coding, thereby reducing the system data transmission completion time.

[0004] Technical solution: To solve the above technical problems, the technical solution adopted by the present invention is:

[0005] In a first aspect, a rate-aware network coding method based on instantly decodable network coding is provided, comprising:

[0006] Step (1): constructing a corresponding RA-IDNC coding relationship diagram according to the link capacity from the base station to the user, the data packet information that the user needs to receive, and the rate-aware-instantaneously-decodable network coding RA-IDNC network coding conditions;

[0007] Step (2): Calculate the weights of all nodes corresponding to the user with the maximum initial completion time in the instant decodable network coding IDNC graph in the RA-IDNC coding relationship graph, select the node with the largest weight, and add this node to the maximum weight group;

[0008] Step (3): in the RA-IDNC coding relationship graph, only the nodes that have a connection edge with the selected maximum weight node are retained, and the RA-IDNC coding relationship graph is updated;

[0009] Step (4): If the node set in the updated RA-IDNC coding relationship graph is not an empty set, calculate the weights of all nodes and go to step (3); otherwise, output the maximum weight coding group.

[0010] In some embodiments, step (1), constructing a corresponding RA-IDNC coding relationship diagram according to the link capacity from the base station to the user in the cell, the data packet information that the user needs to receive, and the RA-IDNC network coding condition, includes:

[0011] Node v in the RA-IDNC coding relationship diagram u,j,r Indicates receiving user C u Request Data Packet P j , the data packet transmission rate is r; node v in the RA-IDNC coding relationship diagram u,j,r With v u',j',r' The existence of a coded connection edge is determined by satisfying at least one of the following two conditions:

[0012] (3) r = r';

[0013] (4)P j =P j' or (P j ,P j' )∈H u' ×H u

[0014] Where u,j and u',j' are the numbers of the user and data packet respectively, H u' , H u Indicates user C u' , C u Already owned data packet (H=has).

[0015] In some embodiments, step (2) comprises:

[0016] Step 2.1: At a given time slot t, calculate the lower bound of the individual completion time for all users; this lower bound is calculated for each user individually, without exploiting the interdependence of user packet reception; and select the user U with the largest individual completion time m;

[0017] Step 2.2: Calculate user U m The weights of all nodes, select the node with the largest weight, and add this node to the maximum weight group.

[0018] Furthermore, in step 2.1, at a given time slot t, the lower bound of the single completion time for all users is calculated. k (t), including:

[0019]

[0020] Where W k (0) is user U k The initial requirement set size is, B is the data packet size, Is user U k The cumulative time delay, From base station to user U k channel capacity.

[0021] Furthermore, in step 2.2, the user U is calculated m The weight of all nodes include:

[0022]

[0023] Where δ(v u,j,r ) indicates that it is related to v in the RA-IDNC coding relationship diagram m,j,r The set of nodes that have edges connecting them.

[0024] In some embodiments, before step (2), the maximum weight clique is initialized to an empty set.

[0025] In a second aspect, the present invention provides a rate-aware network coding device based on instantly decodable network coding, comprising a processor and a storage medium;

[0026] The storage medium is used to store instructions;

[0027] The processor is used to operate according to the instructions to execute the steps of the method according to the first aspect.

[0028] In a third aspect, the present invention provides a storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the method described in the first aspect.

[0029] Beneficial effects: The rate-aware network coding method and device based on instantly decodable network coding provided by the present invention have the following advantages: Based on the instantly decodable network coding technology, the present invention fully combines the dynamic transmission rate and the use of the lower limit of a single completion time, and minimizes the completion time of the current time slot coding data transmission by selecting the coding group. Studies have shown that the rate-aware instantly decodable network coding system can achieve significant performance gains compared to the traditional instantly decodable network coding system, which is specifically reflected in reducing the system transmission data completion time. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic diagram of a process of constructing a maximum weighted clique according to a method of an embodiment of the present invention;

[0031] Figure 2 is a RA-IDNC coding relationship diagram according to an embodiment of the present invention;

[0032] Figure 3 It is a matlab simulation diagram according to one embodiment of the present invention. DETAILED DESCRIPTION

[0033] The present invention will be further described below in conjunction with the accompanying drawings and embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0034] In the description of the present invention, "several" means more than one, "many" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0035] In the description of the present invention, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0036] Example 1

[0037] A rate-aware network coding method based on instantly decodable network coding comprises the following steps:

[0038] Step (1): constructing a corresponding RA-IDNC coding relationship diagram according to the link capacity from the base station to the user in the cell, the data packet information that the user needs to receive, and the RA-IDNC network coding conditions;

[0039] Step (2): Initialize the maximum weight group to an empty set;

[0040] Step (3): Calculate the weights of all nodes corresponding to the user with the maximum initial completion time in the IDNC graph in the RA-IDNC coding relationship graph, select the node with the largest weight, and add it to the maximum weight group;

[0041] Step (4): only retain the nodes that have connecting edges with the selected maximum weight node in the RA-IDNC coding relationship graph, and update the RA-IDNC coding relationship graph;

[0042] Step (5): If the node set in the updated RA-IDNC coding relationship graph is not an empty set, calculate the weights of all nodes and go to step (3); otherwise, output the maximum weight coding group.

[0043] The formula for minimizing completion time can be expressed as:

[0044]

[0045] Where W k (0) is device U k The initial requirement set size is, B is the data packet size, Is the device U k In Scheduling The cumulative time delay in strategy middle Is the device U k The harmonic mean of the transfer rate that can be immediately decoded.

[0046] Given a time slot t, calculate the lower bound of the single completion time for all users. This lower bound is calculated for each user individually, without exploiting the interdependence of user packet reception. And select the user U with the largest single completion time m , calculate user U m The weights of all nodes, select the node with the largest weight, and add it to the maximum weight group.

[0047] In order to reduce the computational complexity, the following calculation method is used to calculate the lower limit of the single completion time of all users:

[0048]

[0049] By selecting the optimal transformation of the coding group formula, the problem of minimizing the completion time of all users after the current time slot coding transmission can be solved by selecting the maximum weight group algorithm. Figure 1 As shown, the specific method is:

[0050] Step 1: Initialization;

[0051] The RA-IDNC coding relationship diagram corresponding to the user node is as follows:

[0052] Initialize the maximum weight group

[0053] Calculate the weights of all nodes of the user with the maximum initial completion time

[0054] Take the node with the largest weight v * u,j,r ,renew

[0055] Step 2: Iterative operation;

[0056] The node v * u,j,r and nodes that are not connected to it from Delete and get the subgraph

[0057] if Continue to iterate and calculate all node weights and update Run until Otherwise, output the maximum weight group

[0058] Compared with traditional IDNC, RA-IDNC generates more nodes because it includes the choice of rate. To generate a node set, RA-IDNC first generates a node set for each user C. u Introducing Achievable Rate Sets in represents the set of all user link capacities, Indicates user C u link capacity.

[0059] After obtaining the user's achievable rate set, the corresponding RA-IDNC coding relationship graph can be constructed by combining the data packet information that the user needs to receive and the RA-IDNC network coding conditions. u,j,r Indicates receiving user C u Request Data Packet P j , the data packet transmission rate is r.

[0060] like Figure 2 The following is an example of the RA-IDNC coding relationship diagram. The base station broadcasts 4 data packets P1, P2, P3, and P4 to 3 users C1, C2, and C3. The link capacity from the base station to the users is R1 = 4.4 bit / s, R2 = 3.2 bit / s, and R1 = 1.8 bit / s. It is assumed that user C1 has not received data packet P1, user C2 has not received data packets P2 and P4, and user C3 has not received data packets P1 and P3. The rate sets of users C1, C2, and C3 are Therefore, the base station to user C1 can generate node v 1,1,4.4 , v 1,1,3.2 , v 1,1,1.8 ; User C2 can generate node v 2,2,3.2 , v 2,2,1.8 , v 2,4,3.2 , v 2,4,1.8 ; Similarly, user C3 can generate node v 3,1,1.8 , v 3,3,1.8 .

[0061] Node v in the RA-IDNC coding relationship diagram u,j,r With v u',j',r' The existence of a coded connection edge is determined by satisfying at least one of the following two conditions:

[0062] (1) r = r';

[0063] (2)P j =P j' or (P j ,P j' )∈H u' ×H u .

[0064] According to the formula T k (t) Calculate the lower limit completion time of each user and select the node set formed by the user with the maximum completion time from the constructed RA-IDNC relationship graph, according to the weight formula Calculate the maximum weight node v * u,j,r . Compute Node v 3,1,1.8 and v 3,3,1.8 The weight is ω 3,1,1.8 =9.72,ω 3,3,1.8 =6.48, select node v 3,1,1.8 For the node with the largest weight, delete it and the nodes that are not connected to it in the graph and calculate the remaining nodes v 1,1,1.8 , v 2,4,1.8 and v 2,2,1.8 The weight is ω 1,1,1.8 =6.48,ω 2,4,1.8 =ω 2,2,1.8=3.24, similarly, we can then select the node with the largest weight v 1,1,1.8 and v 2,4,1.8 , can form an independent coding node subset (i.e., an independent maximum weight group) κ = {v 3,1,1.8 ,v 1,1,1.8 ,v 2,4,1.8}, the corresponding network coding method is that the base station sends the coded data packet The coded data transmission rate is 1.8 bit / s. If each user can correctly receive the coded packet, users C1 and C3 can obtain the data packet P1 they need through network decoding, and user C2 can obtain the data packet P4 they need through network decoding.

[0065] Figure 3 This is a simulation diagram of the performance comparison between the rate-aware network coding method based on IDNC of the embodiment of the present invention and the traditional IDNC coding method and uncoded broadcast transmission, which is mainly aimed at the completion time comparison achieved by different numbers of users. The base station is located in the center of the cellular cell, and the users are evenly distributed in the cell. The physical layer parameters adopted by the present invention are: cellular cell diameter 400m, ideal channel estimation, Rayleigh fading channel model, transmission power -43.2dBm / Hz, and noise power -172dBm / Hz. The number of fixed data packets N = 20, and the data packet size B = 1Mb. It can be seen that the completion time of the three schemes is constantly increasing with the increase in the number of users, and the rate-aware network coding method based on IDNC proposed by the present invention is superior to the traditional IDNC and uncoded broadcast transmission methods because it uses a new IDNC graph and considers the lower limit of the dynamic transmission rate and the single completion time in the decision. Moreover, the traditional IDNC blindly adopts the minimum channel capacity from the base station to other users as the transmission rate, and cannot jointly consider the transmission rate selection and the coding data packet selection. As expected, the uncoded broadcast scheme performs poorly due to the neglect of network coding and dynamic rate adaptation.

[0066] Example 2

[0067] In a second aspect, the present embodiment provides a rate-aware network coding device based on instantly decodable network coding, including a processor and a storage medium;

[0068] The storage medium is used to store instructions;

[0069] The processor is used to operate according to the instructions to execute the steps of the method according to embodiment 1.

[0070] Example 3

[0071] In a third aspect, this embodiment provides a storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of the method described in Example 1 are implemented.

[0072] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0073] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0074] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0075] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0076] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A rate-aware network coding method based on instantly decodable network coding, characterized in that: include: Step (1): constructing a corresponding RA-IDNC coding relationship diagram according to the link capacity from the base station to the user, the data packet information that the user needs to receive, and the rate-aware-instantaneously-decodable network coding RA-IDNC network coding conditions; Step (2): Calculate the weights of all nodes corresponding to the user with the maximum initial completion time in the instant decodable network coding IDNC graph in the RA-IDNC coding relationship graph, select the node with the largest weight, and add this node to the maximum weight group; specifically include: Step 2.1: At a given time slot t, calculate the lower bound of the individual completion time for all users; this lower bound is calculated for each user individually, without exploiting the interdependence of user packet reception; and select the user U with the largest individual completion time m ; where, at a given time slot t, the lower bound of the single completion time for all users is calculated k (t), including: Where W k (0) is user U k The initial requirement set size is, B is the data packet size, Is user U k The cumulative time delay, From base station to user U k The channel capacity of Step 2.2: Calculate user U m The weights of all nodes are calculated, and the node with the largest weight is selected and added to the maximum weight group; among them, the user U is calculated m The weight of all nodes include: Where δ(v m,j,r ) represents the relationship between node v in the RA-IDNC coding relationship diagram m,j,r There is a set of nodes with connected edges; r represents user C u The data packet transmission rate; v u',j',r' It represents the node in the RA-IDNC coding relationship graph, u', j' are the numbers of the user and data packet respectively; Step (3): in the RA-IDNC coding relationship graph, only the nodes that have a connection edge with the selected maximum weight node are retained, and the RA-IDNC coding relationship graph is updated; Step (4): If the node set in the updated RA-IDNC coding relationship graph is not an empty set, calculate the weights of all nodes and go to step (3); otherwise, output the maximum weight coding group.

2. The rate-aware network coding method based on instantly decodable network coding according to claim 1, characterized in that: According to the link capacity from the base station to the user in the cell, the data packet information that the user needs to receive, and the RA-IDNC network coding conditions, the corresponding RA-IDNC coding relationship diagram is constructed, including: Node v in the RA-IDNC coding relationship diagram u,j,r Indicates receiving user C u Request Data Packet P j , the data packet transmission rate is r; the judgment rule for the existence of a coding connection edge between nodes vu,j,r and vu',j',r' in the RA-IDNC coding relationship graph is to satisfy at least one of the following two conditions: (1) r＝r'； (2)P j =P j' or (P j ,P j' )∈H u' ×H u Where u, j and u', j' are the numbers of the user and data packet respectively, H u' , H u Indicates user C u' , C u Already have the data package.

3. The rate-aware network coding method based on instantly decodable network coding according to claim 1, characterized in that: Before step (2), the maximum weight group is initialized to an empty set.

4. A rate-aware network coding apparatus based on instantly decodable network coding, characterized in that: including processor and storage medium; The storage medium is used to store instructions; The processor is configured to operate according to the instructions to execute the steps of the method according to any one of claims 1 to 3.

5. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 3 are implemented.

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