Random access method for wireless ad hoc network system

Abstract

The invention is applicable to the technical field of wireless ad hoc networks, and provides a random access method for a wireless ad hoc network system, and the ad hoc network system adopts a TDMA (Time Division Multiple Access) scheme. Random access resources are distributed in a time division and frequency division combined mode, and the method comprises the following specific steps: a new node accesses a network; the new node exchanges random access resource information with all network nodes; according to the ad hoc network scale, the node number and the target conflict probability, the new node initiates a random access resource updating request; and all network nodes process the random access resource update requests of new nodes, negotiate and authorize the access resource update requests, update respective corresponding random access resource information, and apply new random access resource configuration. According to the invention, based on a TDMA (Time Division Multiple Access) scheme, the conflict probability in the random access process is effectively avoided and the performance, efficiency and reliability of the random access of the ad hoc network system are optimized under the condition that the resource overhead is as little as possible through the resource allocation design of combining time division and frequency division.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless ad hoc networks, and specifically to a random access method for a wireless ad hoc network system. Background Art

[0002] A wireless ad hoc network is a network that does not require infrastructure support, in which mobile devices can form a network through direct communication. Such a network can be automatically formed and managed in the absence of fixed base stations or network devices. A key feature of a wireless ad hoc network is the ability of nodes to communicate directly with each other, thus forming an autonomous and decentralized communication structure. The topology of a wireless ad hoc network is flexible and self-adaptive, making it widely used in scenarios where fixed infrastructure is lacking or rapid deployment is required, such as military operations, disaster relief, etc. Random access technology is a mechanism in a wireless communication environment for mobile devices to access the network. In a wireless ad hoc network, due to the constantly changing network topology and member nodes, random access technology becomes particularly important. This technology can effectively handle the situation of nodes joining and leaving the network, ensuring the stability and reliability of the network.

[0003] Currently, there have been some studies and solutions on random access technology in the field of wireless ad hoc networks. These solutions involve technologies such as distributed coordination, resource allocation, and collision avoidance. However, there are some challenges in current wireless ad hoc networks, such as limited spectrum resources, topology changes caused by node mobility, conflicts and competitions during random access, etc. These problems may lead to troubles such as decreased network performance, increased energy consumption, and degraded quality of service. Therefore, a random access method for a wireless ad hoc network system is needed to address the above problems. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a random access method for a wireless ad hoc network system to overcome the limitations and challenges in the prior art and optimize the performance, efficiency, and reliability of random access in the ad hoc network system.

[0005] The present invention is implemented as follows. A random access method for a wireless ad hoc network system, the ad hoc network system adopts a TDMA multiple access scheme. In the frame structure of the ad hoc network system, a superframe is composed of several frames, a frame is composed of several subframes, and a subframe contains several OFDM symbols; random access resources are allocated by combining time division and frequency division. The specific steps are as follows:

[0006] A new node joins the network;

[0007] The new node exchanges random access resource information with all the nodes in the network;

[0008] According to the scale of the ad hoc network, the number of nodes, and the probability of target conflict, the new node initiates a random access resource update request;

[0009] All nodes on the network process the random access resource update request of the new node, negotiate and authorize the access resource update request, and update their corresponding random access resource information and apply the new random access resource configuration.

[0010] As a further solution of the present invention: one subframe contains 14 OFDM symbols, and parallel transmission of high-speed serial data is achieved through frequency division multiplexing. OFDM is divided into 100 resource blocks in the frequency domain. To support random access, the 100 resource blocks are divided into resource block groups with 6 resource blocks as a group.

[0011] As a further solution of the present invention: when a new node joins the ad hoc network, the new node completes the synchronization of the ad hoc network nodes through synchronous search and parses the system message of the corresponding node; the new node selects an optimal node for random access.

[0012] As a further solution of the present invention: the step of the new node selecting an optimal node for random access specifically includes:

[0013] The new node sends a random access preamble signal to the network node;

[0014] The node on the network sends the corresponding sending resource authorization to the new node;

[0015] The new node sends the random access request content at the time domain and frequency domain position specified by the sending resource grant;

[0016] The network node receives the random access request content and sends the random access authorization content to the new node.

[0017] As a further solution of the present invention: the random access resource information includes: the random access time domain subframe and frequency domain resource block group number of each online node.

[0018] As a further solution of the present invention: the random access resource update request includes the random access resources that the new node needs to apply for and the random access resources that the networked nodes need to modify accordingly.

[0019] As a further solution of the present invention: when the number of nodes in the network is lower than a certain threshold value, the new node sharing the resource group with the nodes in the network through frequency division, at this time, the random access preamble and the random access sending resource authorization only need 1 subframe in the time domain; for the random access request content and the random access authorization content, it is necessary to reserve 2 subframes of resources.

[0020] As a further solution of the present invention: when the number of online nodes exceeds a certain threshold value, the newly-entered node adds the corresponding reserved time domain subframes of random access preamble, random access sending resource authorization, random access request content and random access authorization content, and sends random access resource update request information to the online node.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] In the present invention, after a new node enters the network, the new node exchanges random access resource information with all nodes in the network, and then the new node initiates a random access resource update request according to the scale of the self-organizing network, the number of nodes and the target conflict probability; all nodes in the network process the random access resource update request of the new node, negotiate and authorize the access resource update request, and update their respective corresponding random access resource information, and apply the new random access resource configuration. Based on the TDMA multiple access scheme, the present invention effectively avoids the conflict probability in the random access process with as little resource overhead as possible through the resource allocation design combining time division and frequency division, and optimizes the performance, efficiency and reliability of random access in the self-organizing network system. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is a flow chart of a random access method for a wireless ad hoc network system.

[0024] Figure 2 The present invention is a frame structure diagram of a wireless ad hoc network system in a random access method of the wireless ad hoc network system.

[0025] Figure 3 The present invention is a time domain and frequency domain structure diagram of a subframe of a wireless ad hoc network system in a random access method of the wireless ad hoc network system.

[0026] Figure 4 The present invention is an example diagram of random access resource allocation when the number of nodes in the network is lower than a threshold value in a random access method of a wireless ad hoc network system.

[0027] Figure 5 The present invention is an example diagram of random access resource allocation when the number of nodes in the network is higher than a threshold value in a random access method of a wireless ad hoc network system. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and specific 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.

[0029] The specific implementation of the present invention is described in detail below in conjunction with specific embodiments.

[0030] like Figure 1 , Figure 2and Figure 3 As shown in Figure 3 , an embodiment of the present invention provides a method for random access in a wireless ad hoc network system. The method includes the following steps:

[0031] S100, a new node accesses the network;

[0032] S200, the new node exchanges random access resource information with all the nodes in the network;

[0033] S300, according to the ad hoc network scale, the number of nodes, and the target collision probability, the new node initiates a random access resource update request;

[0034] S400, all the nodes in the network process the random access resource update request of the new node, negotiate and authorize the access resource update request, and update their respective corresponding random access resource information, and apply the new random access resource configuration. Thus, the random access resource update is completed.

[0035] It should be noted that the ad hoc network system adopts a TDMA (Time Division Multiple Access) multiple access scheme. TDMA is a wireless communication technology used to achieve time division multiple access in a wireless ad hoc network. Compared with other multiple access schemes, TDMA ad hoc networks have the advantages of high time efficiency, good synchronization performance, and strong anti-interference ability. In the frame structure of the ad hoc network system, a superframe consists of several (N) frames, and the numbers of each frame are 0, 1, …, N - 1 and repeat in units of superframes. A frame consists of several (M) subframes, and the numbers of each subframe are 0, 1, …, M - 1. A subframe contains 14 OFDM symbols; the random access resources are allocated by a combination of time division and frequency division. OFDM (Orthogonal Frequency Division Multiplexing) is a kind of orthogonal frequency division multiplexing technology, which actually belongs to a type of multi-carrier modulation. It realizes the parallel transmission of high-speed serial data through frequency division multiplexing. It has good anti-multipath fading ability and is widely used in high data rate communications. In the embodiment of the present invention, OFDM is divided into 100 resource blocks (RBs) in the frequency domain. To support random access, the 100 resource blocks are divided into 16 resource block groups with 6 resource blocks in each group.

[0036] In the embodiment of the present invention, in a wireless ad hoc network system, each ad hoc network node needs to reserve a random access resource for other newly joined nodes to access the network through it. If more random access resources are reserved, the probability of random access conflict when multiple nodes access a node simultaneously can be reduced, but the corresponding reservation overhead will increase; conversely, if fewer random access resources are reserved, the reservation overhead will be reduced accordingly, but the probability of random access conflict will also increase. Therefore, how to compromise between the reservation resource overhead and the random access conflict probability to ensure that the random access performance is not affected with as little overhead as possible is the difficulty in implementing random access in the ad hoc network system.

[0037] To achieve efficient random access, the present invention adopts a resource allocation design combining time division and frequency division, and combines a dynamic random access resource allocation and scheduling method to achieve as little random access reservation resource overhead as possible under a reasonable random access conflict probability. When a new node joins the ad hoc network, the new node completes the synchronization of the ad hoc network nodes through synchronization search and parses the system message of the corresponding node; the new node selects an optimal node for random access.

[0038] In the embodiment of the present invention, the step of the new node selecting an optimal node for random access specifically includes: the new node sends a random access preamble signal to the in-network nodes; the in-network nodes send corresponding transmission resource authorizations to the new node; the new node sends random access request content at the time domain and frequency domain positions specified by the transmission resource authorization; the in-network nodes receive the random access request content and send random access authorization content to the new node. The random access resource information includes: the random access time domain subframe and the frequency domain resource block group number of each in-network node. The random access resource update request includes the random access resources that the new node needs to apply for and the random access resources that the in-network nodes need to modify correspondingly.

[0039] As Figure 4 and Figure 5 shown, as a preferred embodiment of the present invention, when the number of in-network nodes is lower than a certain threshold, the newly joined nodes share the resource group with the in-network nodes through frequency division. At this time, the random access preamble and the random access transmission resource authorization only need 1 subframe in the time domain; for the random access request content and the random access authorization content, since the message content they carry is more, 2 subframes of resources need to be reserved. When the number of in-network nodes exceeds a certain threshold, only using frequency division cannot ensure that the conflict probability is lower than the target threshold. Therefore, the newly joined nodes increase the reserved time domain subframes for the corresponding random access preamble, random access transmission resource authorization, random access request content, and random access authorization content, and send random access resource update request information to the in-network nodes.

[0040] The above only describes the preferred embodiments of the present invention in detail and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

[0041] It should be understood that although the steps in the flowcharts of the embodiments of the present invention are shown sequentially as indicated by the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise clearly stated in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, at least a part of the steps in each embodiment may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential either, but can be executed alternately or in turn with at least a part of other steps or sub-steps or stages of other steps.

[0042] Those of ordinary skill in the art can understand that all or part of the processes of implementing the methods in the above embodiments can be completed by instructing relevant hardware through a computer program. The program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, storage, database, or other medium used in the embodiments provided in the present application can include non-volatile and / or volatile memories. Non-volatile memories can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memories can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and Rambus dynamic RAM (RDRAM), etc.

[0043] Other embodiments of the present disclosure will be readily contemplated by those skilled in the art in view of the disclosure in the specification and the embodiments. This application is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include known common general knowledge or conventional technical means in the technical field not disclosed in the present disclosure. The specification and the embodiments are only regarded as exemplary, and the true scope and spirit of the present disclosure are pointed out by the claims.

Claims

1. A random access method for a wireless ad hoc network system, characterized in that, The self-organizing network system adopts the TDMA multiple access scheme. In the frame structure of the self-organizing network system, a superframe is composed of several frames, a frame is composed of several subframes, and a subframe contains several OFDM symbols; random access resources are allocated by combining time division and frequency division, and the specific steps are as follows: New nodes join the network; The new node exchanges random access resource information with all nodes on the network; According to the scale of the ad hoc network, the number of nodes, and the probability of target conflict, the new node initiates a random access resource update request; All nodes on the network process the random access resource update request of the new node, negotiate and authorize the access resource update request, and update their corresponding random access resource information and apply the new random access resource configuration.

2. The random access method of the wireless ad hoc network system according to claim 1, characterized in that One subframe contains 14 OFDM symbols, and parallel transmission of high-speed serial data is achieved through frequency division multiplexing. OFDM is divided into 100 resource blocks in the frequency domain. To support random access, the 100 resource blocks are divided into resource block groups with 6 resource blocks as a group.

3. The random access method of the wireless ad hoc network system according to claim 1, wherein When a new node joins the ad hoc network, the new node completes the synchronization of the ad hoc network nodes through synchronous search and parses the system message of the corresponding node; the new node selects an optimal node for random access.

4. The random access method of the wireless ad hoc network system according to claim 3, wherein The step of the new node selecting an optimal node for random access specifically includes: The new node sends a random access preamble signal to the network node; The node on the network sends the corresponding sending resource authorization to the new node; The new node sends the random access request content at the time domain and frequency domain position specified by the sending resource grant; The network node receives the random access request content and sends the random access authorization content to the new node.

5. The random access method of the wireless ad hoc network system according to claim 1, characterized in that, The random access resource information includes: random access time domain subframe and frequency domain resource block group number of each online node.

6. The random access method of the wireless ad hoc network system according to claim 1, characterized in that The random access resource update request includes the random access resources that the new node needs to apply for and the random access resources that the networked nodes need to modify accordingly.

7. The random access method of the wireless ad hoc network system according to claim 1, characterized in that When the number of nodes in the network is lower than a certain threshold, the new nodes share resource groups with the nodes in the network through frequency division. At this time, the random access preamble and random access sending resource authorization only require 1 subframe in the time domain; for the random access request content and random access authorization content, 2 subframes of resources need to be reserved.

8. The random access method of the wireless ad hoc network system according to claim 7, wherein When the number of nodes in the network exceeds a certain threshold, the newly-entered node adds the corresponding reserved time domain subframes of random access preamble, random access sending resource authorization, random access request content and random access authorization content, and sends random access resource update request information to the network node.

Images