A non-uniform speed vehicle task offloading method based on V2V collaboration

Abstract

The present invention claims protection for a non-uniform speed vehicle task unloading method based on V2V collaboration, and belongs to the field of communication technology. In a non-uniform speed vehicle edge network, due to the dynamic and disordered changes in network topology and resource status, problems such as decreased network resource utilization and task scheduling failure may be caused. In view of this problem, a non-uniform speed vehicle task unloading method based on V2V collaboration is proposed. This method searches for available cooperative vehicles within a reasonable communication range according to the real-time speed of the vehicle and the positional relationship between the vehicles, dynamically plans the unloading cycle and the task scheduling between the cooperative vehicles, thereby improving the network resource utilization and task completion rate, and reducing the task unloading delay.

Description

Technical Field

[0001] The present invention belongs to the technical field of communication networks, and in particular relates to a non-uniform speed vehicle task unloading method based on V2V collaboration. Background Art

[0002] With the rapid development of mobile communication networks, the application of vehicle-mounted services has received widespread attention from academia and industry. Vehicle-to-vehicle (V2V) communication can be achieved through technologies such as cellular vehicle-to-everything (C_V2X) or dedicated short-range communication (DSRC) based on the IEEE802.11p protocol. At the same time, mobile vehicles equipped with on-board units (OBU) also have certain computing and storage capabilities and can support certain task processing, such as path planning, real-time navigation, etc. Therefore, cars are regarded as one of the important terminals of the current mobile communication network.

[0003] However, the limitations of vehicle terminals in computing and storage capabilities may make it difficult to meet the resource requirements of some vehicle applications, thus affecting the user's service quality experience. Therefore, in the vehicle edge network, offloading tasks to other network nodes with computing and storage resources is an effective way to process tasks. As an information interaction technology between vehicles, V2V can provide close-range information sharing and resource sharing services for moving vehicles. Therefore, using V2V technology to offload tasks generated by vehicles to surrounding idle vehicles for execution can reduce task processing latency and improve network service quality.

[0004] Existing research on V2V cooperative offloading usually only considers simple assumptions about mobility, that is, the vehicle is stationary or driving at a constant speed, and a single unloading destination is used for task scheduling during the unloading process. However, in real life, due to vehicle types, road conditions and the subjective will of the driver, vehicles often have different driving modes and speeds, which may cause dynamic and disordered changes in network topology and resource status. At the same time, the use of a single unloading destination may also cause a decrease in network resource utilization and task scheduling failure, resulting in the deterioration of task completion delay and completion rate indicators. To address the above problems, a non-uniform speed vehicle task offloading method based on V2V collaboration is proposed. This method uses a dynamic programming unloading cycle to find available cooperative vehicles within a reasonable communication range according to the real-time speed of the vehicle and the position relationship between vehicles, so as to schedule tasks at multiple unloading destinations, thereby speeding up task processing and improving network resource utilization and task completion rate. Summary of the invention

[0005] The present invention aims to solve the above problems of the prior art. A non-uniform speed vehicle task unloading method based on V2V collaboration is proposed. The technical solution of the present invention is as follows:

[0006] A method for unloading tasks of non-uniform-speed vehicles based on V2V collaboration, wherein a set of road vehicles is represented as I, and each vehicle is equipped with a corresponding on-board unit OBU to provide task unloading services, characterized in that task unloading is performed in a dynamic periodic scheduling manner, and specifically includes the following steps:

[0007] Step 101: Vehicle i initiates a task unloading request Z i , where i∈I, obtain the task data volume d i , task computational complexity c i , Task delay threshold Initialize the vehicle's completed tasks The number of cycles k = 0, the system time t = 0;

[0008] Step 102: Let k = k + 1, according to the real-time speed v of vehicle i i , calculate the duration of its kth cycle τ i,k ;

[0009] Step 103: Create a temporary set I temp , for each vehicle i′ without unloading task within the communication range of vehicle i, according to its speed v i′ and the relative distance l from vehicle i i,i′ Calculate the sustainable communication time t i,i′ , t i,i′ ≥τ i,k The vehicle i′ is placed in I temp , so that the cooperative vehicle task completion mark

[0010] Step 104: for set I temp For each vehicle i′ in the normalized continuous communication time t with vehicle i i,i′ and available computing resources f i′ , and according to the normalized sustainable communication time t′ i,i′ and normalized computational resources f′ i′ Calculate its comprehensive screening index e′ i′ ;

[0011] Step 105: Set I temp Press e′ for all vehicles in i′ Arrange in descending order, and put the first n vehicles into the cooperative vehicle set I′, and delete the set I temp ;

[0012] Step 106: For each vehicle i′ in the set I′, the computing resources f that can be provided by the vehicle i′ are i′ and the transmission rate r of vehicle i i , calculate the amount of collaborative unloading tasks that can be performed by vehicle i in the kth cycle Perform task scheduling and offloading;

[0013] Step 107: If Jump to step 108, otherwise, jump to step 110;

[0014] Step 108: If Jump to step 109, otherwise, set Jump to step 110;

[0015] Step 109: For each cooperative vehicle i′ in I′, if the cooperative task is completed Calculate and return the result, let Release the computing resources of cooperative vehicles i′ , delete i′ from the set I′ and jump to step 107; otherwise, jump to step 107;

[0016] Step 110: Update the mission delay threshold of vehicle i according to Determine the amount of completed tasks for vehicle i make If d i >0, jump to step 102, otherwise, jump to step 111;

[0017] Step 111, the algorithm ends;

[0018] The k-th cycle duration τ of vehicle i in step 102 i,k The calculation method is shown in formula (1):

[0019]

[0020] In formula (1), τ0 represents the minimum unloading period, γ and η are constants, and v i represents the current speed of vehicle i;

[0021] In step 103, the vehicle i and the cooperative vehicle i′ can continue to communicate for a time t i,i′ The calculation method is shown in formula (2):

[0022]

[0023] In formula (2), R V2V represents the communication range between vehicles, l i,i′ represents the distance between vehicle i and vehicle i′, vi′ represents the current speed of vehicle i′;

[0024] The normalized sustainable communication time t′ in step 104 i,i′ and normalized computational resources f′ i′ The calculation method of is shown in formula (3) and formula (4):

[0025]

[0026] The comprehensive screening index e′ of vehicle i′ in step 104 i′ The calculation method of is shown in formula (5):

[0027] e′ i′ =α·t′ i,i′ +β·f′ i′ (5)

[0028] In formula (5), α and β represent weight factors;

[0029] The amount of collaborative unloading tasks of the collaborative vehicle i′ in step 106 The calculation method of is shown in formula (6):

[0030]

[0031] In formula (6), f i′ represents the computing resources that cooperative vehicle i′ can provide, r i represents the transmission rate of vehicle i, c i Indicates the computational complexity of the task;

[0032] The amount of completed tasks of vehicle i in step 110 The calculation method of is shown in formula (7):

[0033]

[0034] The advantages and beneficial effects of the present invention are as follows:

[0035] Existing research on V2V cooperative unloading mainly focuses on scenarios of stationary vehicles or vehicles moving at a uniform speed, and usually uses a single unloading destination for task scheduling, without considering the problem of multi-vehicle cooperative unloading under non-uniform speed conditions. The non-uniform movement of vehicles may cause dynamic and disordered changes in network topology and resource status, resulting in a decrease in network resource utilization and failure of task scheduling, which in turn leads to the deterioration of task completion delay and completion rate indicators. In response to the above problems, a non-uniform speed vehicle task unloading method based on V2V collaboration is proposed. According to the real-time speed of the vehicle and the position relationship between the vehicles, this method searches for available cooperative vehicles within a reasonable communication range, constructs a workshop cooperative unloading model based on dynamic periodic scheduling, and plans the unloading cycle and task scheduling between cooperative vehicles in real time, thereby improving network resource utilization and task completion rate, and reducing task unloading delay. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The present invention provides a flowchart of a method for unloading tasks of non-uniform-speed vehicles based on V2V collaboration in a preferred embodiment. DETAILED DESCRIPTION

[0037] The following will describe the technical solutions in the embodiments of the present invention in detail in conjunction with the accompanying drawings in the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention.

[0038] The technical solution of the present invention to solve the above technical problems is:

[0039] The concepts and models involved in the content of the present invention are as follows.

[0040] 1. Network Model

[0041] The set of road vehicles is represented as I (i∈I), and each vehicle is equipped with a corresponding on-board unit OBU to provide task offloading services. Task offloading is performed between vehicles through V2V.

[0042] 2. Other symbols involved in the present invention are explained as follows.

[0043] v i : Current vehicle speed

[0044] τ i,k : The current uninstall cycle

[0045] d i : Task data size

[0046] c i :Task computational complexity

[0047] Task delay threshold

[0048] The amount of tasks completed by vehicle i

[0049] t i,i′ : The sustainable communication time between vehicle i′ and vehicle i

[0050] f i′ :Vehicle i′ can provide computing resources

[0051] t′ i,i′ : Normalized sustainable communication time between vehicle i′ and vehicle i

[0052] f′ i′ :The normalization of vehicle i′ can provide computing resources f i′

[0053] e′ i′ : Comprehensive screening index of vehicle i′

[0054] The amount of collaborative unloading tasks for vehicle i′

[0055] R V2V :Communication range between vehicles

[0056] τ0: Minimum unloading period

[0057] γ, η: period adjustment factors

[0058] α, β: weight factors

[0059] l i,i′ : The distance between vehicle i and cooperative vehicle i′

[0060] n: size of cooperative vehicle set

[0061] The technical solution of the present invention is described as follows.

[0062] 1. The k-th cycle duration τ of vehicle i i,k

[0063] The calculation method is shown in formula (1):

[0064]

[0065] In formula (1), τ0 represents the minimum unloading period, γ and η are constants, and v i Represents the current speed of vehicle i.

[0066] 2. The continuous communication time t between vehicle i and cooperative vehicle i′ i,i′

[0067] The calculation method is shown in formula (2):

[0068]

[0069] In formula (2), R V2V represents the communication range between vehicles, l i,i′ represents the distance between vehicle i and vehicle i′, v i′ represents the current speed of vehicle i′.

[0070] 3. Normalized sustainable communication time t′ i,i′ and normalized computational resources f′ i′

[0071] The calculation method is shown in formula (3) and formula (4):

[0072]

[0073] 4. Comprehensive screening index e′ of vehicle i′ i′

[0074] The calculation method is shown in formula (5):

[0075] e′ i′ =α·t′ i,i′ +β·f′ i′ (5)

[0076] In formula (5), α and β represent weight factors.

[0077] 5. The amount of collaborative unloading tasks for vehicle i′

[0078] The calculation method is shown in formula (6):

[0079]

[0080] In formula (6), f i′ represents the computing resources that cooperative vehicle i′ can provide, r i represents the transmission rate of vehicle i, c i Indicates the computational complexity of the task.

[0081] 6. Completed tasks of vehicle i

[0082] The calculation method is shown in formula (7):

[0083]

[0084] A method for unloading tasks of non-uniform speed vehicles based on V2V collaboration, and its specific implementation method includes the following steps.

[0085] Step 1: Vehicle i initiates a task offloading request Z i , get the task data volume d i, the computational complexity of the task is c i , task delay threshold Initialize the vehicle's completed tasks The number of cycles k = 0, the system time t = 0;

[0086] Step 2: Let k = k + 1, according to the real-time speed v of vehicle i i , calculate the duration of its kth cycle τ i,k ;

[0087] Step 3: Create a temporary collection I temp , for each vehicle i′ without unloading task within the communication range of vehicle i, according to its speed v i′ and the relative distance l from vehicle i i,i′ Calculate the sustainable communication time t i,i′ , t i,i′ ≥τ i,k The vehicle i′ is placed in I temp , so that the cooperative vehicle task completion mark

[0088] Step 4: For set I temp For each vehicle i′ in the normalized continuous communication time t with vehicle i i,i′ and available computing resources f i′ , and according to the normalized sustainable communication time t′ i,i′ and normalized computational resources f′ i′ Calculate its comprehensive screening index e′ i′ ;

[0089] Step 5: Set I temp Press e′ for all vehicles in i′ Arrange in descending order, and put the first n vehicles into the cooperative vehicle set I′, and delete the set I temp ;

[0090] Step 6: For each vehicle i′ in the set I′, the computing resources f that can be provided by vehicle i′ i′ and the transmission rate r of vehicle i i , calculate the amount of collaborative unloading tasks that can be performed by vehicle i in the kth cycle Perform task scheduling and offloading;

[0091] Step 7: If Jump to step 8, otherwise, jump to step 10;

[0092] Step 8: If Jump to step 9, otherwise, let Jump to step 10;

[0093] Step 9: For each cooperative vehicle i′ in I′, if the cooperative task is completed Calculate and return the result, let Release the computing resources of cooperative vehicles i′ , delete i′ from the set I′ and jump to step 7, otherwise, jump to step 7;

[0094] Step 10: Update the mission delay threshold of vehicle i according to Determine the amount of completed tasks for vehicle i make If d i >0, jump to step 2, otherwise, jump to step 11;

[0095] Step 11: The algorithm ends.

[0096] The systems, devices, modules or units described in the above embodiments may be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer. Specifically, the computer may be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices.

[0097] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0098] The above embodiments should be understood to be only used to illustrate the present invention and not to limit the protection scope of the present invention. After reading the contents of the present invention, technicians can make various changes or modifications to the present invention, and these equivalent changes and modifications also fall within the scope defined by the claims of the present invention.

Claims

1. A non-uniform speed vehicle task unloading method based on V2V collaboration, wherein a set of road vehicles is represented as I, and each vehicle is equipped with a corresponding on-board unit OBU to provide task unloading service, characterized in that: The task offloading is performed by dynamic periodic scheduling, which specifically includes the following steps: Step 101: Vehicle i initiates a task unloading request Z i , where i∈I, obtain the task data volume d i , task computational complexity c i , task delay threshold t i thr , initialize the vehicle's completed task volume d i c =0, cycle number k=0, system time t=0; Step 102: Let k = k + 1, according to the real-time speed v of vehicle i i , calculate the duration of its kth cycle τ i,k ; Step 103: Create a temporary set I temp , for each vehicle i′ without unloading task within the communication range of vehicle i, according to its speed v i′ and the relative distance l from vehicle i i,i′ Calculate the sustainable communication time t i,i′ , t i,i′ ≥τ i,k The vehicle i′ is placed in I temp , so that the cooperative vehicle task completion mark Step 104: for set I temp For each vehicle i′ in the normalized continuous communication time t with vehicle i i,i′ and available computing resources f i’ , and according to the normalized sustainable communication time t i ' ,i‘ and normalized computing resources f i’ 'Calculate its comprehensive screening index e i‘ '; Step 105: Set I temp Press e for all vehicles in i’ 'Sort in descending order, and put the first n vehicles into the cooperative vehicle set I', delete the set I temp ; Step 106: For each vehicle i′ in the set I′, the computing resources f that can be provided by the vehicle i′ are i′ and the transmission rate r of vehicle i i , calculate the amount of collaborative unloading tasks that can be performed by vehicle i in the kth cycle Perform task scheduling and offloading; Step 107: If Jump to step 108, otherwise, jump to step 110; Step 108: If Jump to step 109, otherwise, set Jump to step 110; Step 109: For each cooperative vehicle i′ in I′, if the cooperative task is completed Calculate and return the result, let Release the computing resources of cooperative vehicles i′ , delete i′ from the set I′ and jump to step 107; otherwise, jump to step 107; Step 110: Update the mission delay threshold of vehicle i according to Determine the amount of completed tasks for vehicle i make If d i >0, jump to step 102, otherwise, jump to step 111; Step 111, the algorithm ends; The k-th cycle duration τ of vehicle i in step 102 i,k The calculation method is shown in formula (1): In formula (1), τ0 represents the minimum unloading period, γ and η are constants, and v i represents the current speed of vehicle i; In step 103, the vehicle i and the cooperative vehicle i′ can continue to communicate for a time t i,i′ The calculation method is shown in formula (2): In formula (2), R V2V represents the communication range between vehicles, l i,i′ represents the distance between vehicle i and vehicle i′, v i′ represents the current speed of vehicle i′; The normalized sustainable communication time t in step 104 i ' ,i′ and normalized computing resources f i’ The calculation method of ' is shown in formula (3) and formula (4): The comprehensive screening index e of vehicle i′ in step 104 i‘ The calculation method of ' is shown in formula (5): e i‘ '=α·t i ′ ,i′ +β·f i‘ ' (5) In formula (5), α and β represent weight factors; The amount of collaborative unloading tasks of the collaborative vehicle i′ in step 106 The calculation method of is shown in formula (6): In formula (6), f i′ represents the computing resources that cooperative vehicle i′ can provide, r i represents the transmission rate of vehicle i, c i Indicates the computational complexity of the task; The amount of completed tasks of vehicle i in step 110 The calculation method of is shown in formula (7):

Images