CN104581819A

CN104581819A - Slot resource collision determination method and device

Info

Publication number: CN104581819A
Application number: CN201310512686.8A
Authority: CN
Inventors: 李凤; 冯媛; 赵丽
Original assignee: China Academy of Telecommunications Technology CATT
Current assignee: Datang Telecom Technology Industry Holding Co Ltd
Priority date: 2013-10-25
Filing date: 2013-10-25
Publication date: 2015-04-29

Abstract

The invention relates to the field of communication, and discloses a slot resource collision determination method and a slot resource collision determination device, which are used for reducing interference between nodes. In the embodiment of the invention, after a first node receives FI (Frame Information) from another node, if learning about that the other node determines that collision occurs to a slot resource according to the received FI, the first node determines that the slot resource is in a collision state when determining that a node occupying the slot resource is a one-hop neighbor node of the first node according to locally stored slot state information. In such a manner, in case of collision of a certain slot resource in the system, the node detecting the collision state can timely and effectively transmit slot resource collision information to peripheral nodes, so that severe interference between the nodes using the same slot resource during the transmission of the FI and/or data is effectively avoided, and meanwhile, the use efficiency of the slot resource is improved.

Description

Method and device for determining time slot resource collision

Technical Field

The present invention relates to the field of communications, and in particular, to a method and an apparatus for determining a time slot resource collision.

Background

With the development of vehicle-mounted communication systems and the gradual maturity of mobile ad hoc network technologies, in order to realize real-time, dynamic and intelligent management of vehicles, a Dedicated Short Range Communication (DSRC) protocol for vehicle networking is internationally and specially developed. The DSRC organically connects the vehicle with the vehicle, the vehicle and the infrastructure of the road side through bidirectional information transmission, and supports point-to-point and point-to-multipoint communication.

A Mobile Slotted ALOHA (MS-ALOHA) mechanism is a time-sharing based DSRC Medium Access Control (MAC) layer Access and resource allocation mechanism, and resource allocation is based on a frame structure and takes a slot as a unit. Referring to fig. 1, each N slots form a Frame (denoted as Frame), and slots in each Frame are numbered 0 to N-1, and cycle through frames. Only one vehicle is allowed to transmit in each slot, that is, the Time Division Multiple Access (TDMA) mode is adopted between vehicles. The vehicle not only transmits data of the application layer but also needs to transmit Frame Information (FI) in the occupied time slot, where the FI indicates the occupied status of each slot in one Frame, for example, one possible FI structure is shown in fig. 2.

The basic idea of the MS-ALOHA mechanism is: when any node (such as a vehicle) joins the network, it needs to occupy a timeslot through the idle timeslot resources in the monitoring frame, and if the node does not actively give up the occupied timeslot resources, the occupied timeslot can be used all the time to transmit data, during which other nodes cannot use the timeslot. In an occupied time slot, a node needs to periodically send FI, which carries the condition that other nodes within a two-hop range away from the node occupy the time slot, obtained by the node, indicates the occupation status information (also called time slot status information and time slot information) of each time slot perceived by the node, and gives the time slot for each time slot: time slot occupation state information, a temporary resource Identifier (STI) corresponding to a node occupying a time slot, or a node Identifier, and a priority state of the node occupying the time slot (which may also be considered as a priority state corresponding to data sent by the node occupying the time slot in the time slot); the timeslot occupation state information may express four occupation states of the timeslot: (00) the time slot is represented as an idle state, (10) the time slot is represented as being occupied by other nodes which are one hop away from the node (for short, occupied by one hop of adjacent nodes) or the node, (11) the time slot is represented as being occupied by other nodes which are two hops away from the node (for short, occupied by two hop of adjacent nodes), (01) the time slot is represented as being occupied by more than two other nodes, namely, a collision state; in the time slot which is not occupied by the node, each node can judge the condition that each node occupies the time slot in the adjacent three-hop range by monitoring FI (Fi) sent by the node of the adjacent one hop, and when the time slot resource occupied by the node is found to collide with the resource used by other nodes, a new idle time slot is reserved again. In order to facilitate subsequent description, the following description modes are uniformly adopted for FI and internal information content thereof in the invention:

the node transmitting Frame Information (FI) is called: an FI message, which may also be referred to as FI for short;

referring to fig. 2, the occupancy status information corresponding to each slot indicated in FI is referred to as: a time slot information domain corresponding to each time slot in the FI message;

three types of information (namely, the slot occupation state, the STI and the priority information) given in the occupation status information corresponding to each slot in the FI are respectively called as: the time slot occupation state sub-field, STI sub-field and priority sub-field contained in the time slot information field of each time slot;

it should be noted that the above description is only provided for convenience of the following description, and other description manners may be adopted.

Under the MS-ALOHA mechanism, in the maintenance process of occupied time slots, a node needs to maintain an (N-1) × N time slot state cache table for storing time slot information fields of each time slot carried in FI messages sent by adjacent nodes received on corresponding time slots. For example, referring to fig. 3, the dimension of the time slot state cache table shown in fig. 3 is N × N, and since FI messages sent by the nodes themselves in occupied time slots do not need to be stored, the time slot state cache table actually maintained by the nodes is N-1 rows (assuming that each node only occupies one time slot), and all the (N-1) × N time slot state cache tables described in the subsequent contents of the present invention refer to time slot information for sending FI without storing the time slots occupied by the nodes themselves; the detection field corresponding to the timeslot refers to a timeslot information field corresponding to the timeslot in the FI message sent by occupying the timeslot and is called a "detection field" of the timeslot, and the non-detection field refers to a timeslot information field corresponding to the timeslot in the FI sent by not occupying the timeslot and is called a non-detection field "of the timeslot. Wherein the default value is the default value.

When a node receives an FI message on a time slot, the information content of the row corresponding to the time slot in the time slot state cache table (namely, the content recorded before covering a frame period) is always covered by the information content of the time slot carried in the newly received FI message. The specific process is as follows:

the FI message is generated and sent by the node in the time slot occupied by the node, and each field (domain) needs to be filled according to a certain rule, wherein the field comprises a time slot occupation state sub-domain, an STI sub-domain and a priority sub-domain. After the transmission is finished, the node clears the transmitted FI information.

The method comprises the steps that a node needs to receive FI messages sent by surrounding nodes on a time slot which is not occupied by the node, a time slot state cache table is updated according to the received FI messages, whether the time slot occupied by the node is maintained successfully or not and the occupied state of each time slot of the time slot which is not occupied by the node are judged before the time slot occupied by the node is reached, wherein when the FI is not received on the time slot which is not occupied by the node, the node fills a default value into each domain of a line corresponding to the time slot in the time slot state cache table. The Default value is currently processed in the idle state (00), although other processing manners may be defined.

Under the MS-ALOHA mechanism, any node judges that the time slot resource has collision and has the following two conditions:

1) and the time slot resources occupied by the nodes are collided.

In the (N-1) × N time slot state cache table, if any one of the following conditions occurs in the time slot information indicated on the column (N-1 elements) corresponding to the time slot occupied by the node itself, the time slot occupied by the node itself is considered to be collided:

a. one or more time slot information corresponding to the N-1 element indicates that the time slot is occupied by other nodes different from the node STI (the corresponding time slot occupation status is indicated as 10), and the priority of the node itself is not the highest of all nodes occupying the time slot (including all other nodes indicating that the time slot is the same as that occupied by the node in the time slot information corresponding to the node and the N-1 element).

b. One or more time slot information corresponding to the N-1 element indicates that the time slot is occupied by other nodes different from the node STI (the corresponding time slot occupation status is indicated as 10), and the priority of the node is the highest priority but not the only highest priority node (since there are only 4 priority levels, there may be multiple nodes with the same priority level) in all nodes occupying the time slot (including all other nodes indicating that the time slot corresponding to the node and the N-1 element occupies the same time slot as the node). The node may choose to send FI on its currently occupied slot + N, and in the following flow, if this occurs again, the node may send at slot p +2 × N again with probability p, and think that slot resource collision occurs with probability (1-p).

2) And the time slot resources occupied by the non-nodes are collided.

For N-1 elements in a time slot state cache table corresponding to any time slot occupied by a non-node, if two or more time slot information indicating that the time slot is occupied by two or more nodes (namely STI is different) occurs (the corresponding time slot occupation state indication is 10), the time slot resource is determined to be collided.

As can be seen from the above description, under the MS-ALOHA mechanism, when two or more node occupancies occur in a column corresponding to a timeslot in the (N-1) × N-dimensional timeslot status cache table (i.e., when the timeslot occupational status is indicated as 10), it can be determined that the timeslot has a collision, and at this time, the node sets the timeslot status in FI to 01. However, in the FI generation process, how to process the 01 in the (N-1) × N slot state cache table is not described, which results in that when a certain node has found a slot resource collision, it cannot effectively communicate the information to the node where the slot resource is collided.

For example, referring to fig. 4, assuming that node a and node d occupy the same time slot m, when node d enters, the different transmission time slots of node b and node c result in different time for determining that node d and node a collide. Assuming that after receiving FI sent by node d, node c arrives at its own sending time slot first, according to MS-ALOHA collision mechanism, node a (known by FI of receiving node b) and node d occupy simultaneously in the column corresponding to time slot m in the (N-1) N-dimensional time slot state cache table maintained by node c, therefore, node c determines that time slot m has collided (i.e. time slot occupied state is 01) and generates FI sending, but only node a's occupied state and node c's sending collision state are in the column corresponding to time slot m in the (N-1) N-dimensional time slot state cache table maintained by node a, and only node d's occupied state and node c's sending collision state are in the column corresponding to time slot m in the (N-1) N-dimensional time slot state cache table maintained by node d, and node c's sending collision state, according to the judgment rule that time slot resources occupied by node itself in MS-ALOHA mechanism collide, the node a and the node d both cannot determine that the time slot m is collided in time, and both continue to occupy the time slot m, and because the distance between the node a and the node d is only three hops away (the node more than three hops away can multiplex the time slot resource), when the node a and the node d transmit data on the time slot m at the same time, serious interference can be brought to each other.

Disclosure of Invention

The embodiment of the invention provides a method and a device for determining time slot resource collision, which are used for reducing the interference between nodes.

The embodiment of the invention provides the following specific technical scheme:

in a first aspect, a method for determining a timeslot resource collision includes:

the first node receives FIs sent by other nodes, and learns that the other nodes determine that a time slot resource is collided according to the received FIs;

and when the first node determines that the node occupying the time slot resource is a one-hop neighbor node of the first node according to the locally stored time slot state information, the first node judges that the time slot resource is in a collision state.

Therefore, when the time slot resources in the system collide, the nodes detecting the collision state can timely and effectively transmit the information of the time slot resource collision to the peripheral nodes, so that the nodes using the same time slot resources are effectively prevented from generating strong interference to each other when FI and/or data are transmitted, and meanwhile, the use efficiency of the time slot resources is improved.

With reference to the first aspect, in a first possible implementation manner, a first node determines, according to locally stored timeslot status information, that a node occupying a timeslot resource is a one-hop neighbor node of the first node, including:

if the first node stores a historical time slot state table, the first node determines the node occupying the time slot resource as a one-hop neighbor node of the first node according to the time slot state information recorded in the historical time slot state table; the historical time slot state table records time slot state information stored by a first node in L frames before the current frame, wherein L is a positive integer;

or,

if the first node stores a one-hop neighbor node time slot state table, the first node determines the node occupying the time slot resources as the one-hop neighbor node of the first node according to the node information recorded in the one-hop neighbor node time slot state table; after the first node sends the FI, the time slot state table of the one-hop neighbor node records that the time slot state information corresponding to the non-self-occupation time slot in the time slot state vector is reset, and the saved time slot occupation state is the node information corresponding to the non-self-occupation time slot occupied by the one-hop neighbor node.

Therefore, the first node can obtain the required time slot state information in time, and can quickly judge whether the node occupying the time slot resource is a one-hop neighbor node of the first node.

With reference to the first aspect and the first possible implementation manner of the first aspect, in a second possible implementation manner, after the determining, by the first node, that the timeslot resource is in the collision state, the method further includes:

if the first node maintains a corresponding time slot state vector for each sending time slot, the first node sets the time slot occupation state corresponding to the time slot resource to be a collision state in each maintained time slot state vector;

if the first node maintains a unified time slot state vector for each sending time slot, the first node sets the time slot occupation state corresponding to the time slot resource to be a collision state in the maintained unified time slot state vector.

Therefore, the time slot state information recorded in the maintained time slot state vector can be updated in time so as to be used in the subsequent process.

With reference to the second possible implementation manner of the first aspect, in a third possible implementation manner, the method further includes:

and if the historical time slot state table is stored in the first node, the first node sets the time slot occupation state corresponding to the time slot resource to be a collision state in the historical time slot state table.

Therefore, the time slot state information recorded in the maintained historical time slot state vector can be updated in time so as to be used in the subsequent process.

With reference to the second possible implementation manner of the first aspect, in a fourth possible implementation manner, the method further includes:

and if the first node stores the one-hop neighbor node time slot state table, after the first node sends FI, before resetting the time slot state information corresponding to the non-self-occupation time slot in the time slot state vector, updating the one-hop neighbor node time slot state table according to the node information corresponding to the non-self-occupation time slot occupied by the one-hop neighbor node in the time slot state vector, wherein the time slot occupation state recorded in the time slot state vector is the one-hop neighbor node time slot.

Therefore, the time slot state information recorded in the maintained one-hop neighbor node time slot state table can be updated in time so as to be used in the subsequent process.

In a second aspect, a vehicle node comprises:

the communication unit is used for receiving FIs sent by other nodes and learning that the other nodes judge that a time slot resource is collided according to the received FIs;

and the processing unit is used for judging that the time slot resource is in a collision state when the node occupying the time slot resource is determined to be a one-hop neighbor node of the vehicle node according to the locally stored time slot state information.

With reference to the second aspect, in a first possible implementation manner, the determining, by the processing unit according to locally stored time slot state information, that a node occupying the time slot resource is a one-hop neighbor node of a host vehicle node includes:

if the historical time slot state table is stored, determining the node occupying the time slot resource as a one-hop neighbor node of the vehicle node according to the time slot state information recorded in the historical time slot state table; the historical time slot state table records time slot state information stored by the vehicle node in L frames before the current frame, wherein L is a positive integer;

or,

if the one-hop neighbor node time slot state table is stored, determining the node occupying the time slot resources as the one-hop neighbor node of the vehicle node according to the node information recorded in the one-hop neighbor node time slot state table; after the FI is sent by the vehicle node and before the time slot state information corresponding to the non-self-occupation time slot in the time slot state vector is reset, the stored time slot occupation state is the node information corresponding to the non-self-occupation time slot occupied by the one-hop neighbor node.

Therefore, the vehicle node can obtain the required time slot state information in time, and can quickly judge whether the node occupying the time slot resource is a one-hop neighbor node of the first node.

With reference to the second aspect and the first possible implementation manner of the second aspect, in a second possible implementation manner, the processing unit is further configured to:

after the time slot resource is judged to be in the collision state, if corresponding time slot state vectors are respectively maintained for each sending time slot, the time slot occupation state corresponding to the time slot resource is set to be in the collision state in each maintained time slot state vector; and if a unified time slot state vector is maintained for each sending time slot, setting the time slot occupation state corresponding to the time slot resource in the maintained unified time slot state vector as a collision state.

With reference to the second possible implementation manner of the second aspect, in a third possible implementation manner, the processing unit is further configured to:

and if the historical time slot state table is stored, setting the time slot occupation state corresponding to the time slot resource as a collision state in the historical time slot state table.

With reference to the second possible implementation manner of the second aspect, in a fourth possible implementation manner, the processing unit is further configured to:

and if the one-hop neighbor node time slot state table is stored, after FI is sent, before time slot state information corresponding to the non-self-occupation time slot in the time slot state vector is reset, updating the one-hop neighbor node time slot state table according to node information corresponding to the non-self-occupation time slot occupied by the one-hop neighbor node in the time slot state vector, wherein the time slot occupation state recorded in the time slot state vector is the one-hop neighbor node.

In a third aspect, a vehicle node comprises:

the communication port is used for receiving FIs sent by other nodes and learning that the other nodes determine that a time slot resource is collided according to the received FIs;

and the processor is used for judging that the time slot resource is in a collision state when the node occupying the time slot resource is determined to be a one-hop neighbor node of the vehicle node according to the locally stored time slot state information.

With reference to the third aspect, in a first possible implementation manner, the determining, by the processor, that a node occupying the time slot resource is a one-hop neighbor node of a host vehicle node according to locally stored time slot state information includes:

or,

With reference to the third aspect and the first possible implementation manner of the third aspect, in a second possible implementation manner, the processor is further configured to:

With reference to the second possible implementation manner of the third aspect, in a third possible implementation manner, the processor is further configured to:

With reference to the second possible implementation manner of the third aspect, in a fourth possible implementation manner, the processor is further configured to:

Drawings

Fig. 1 is a diagram illustrating a superframe structure in the prior art;

FIG. 2 is a schematic diagram of a FI structure according to the prior art;

FIG. 3 is a representation of a prior art slot state cache in accordance with an embodiment of the present invention;

FIG. 4 is a schematic diagram of node distribution in the prior art;

FIG. 5 is a diagram illustrating a timeslot status vector according to an embodiment of the present invention;

FIG. 6 is a flowchart illustrating a first node determining a collision of time slot resources according to an embodiment of the present invention;

FIG. 7 is a schematic diagram illustrating occupied time slots of nodes according to an embodiment of the present invention;

fig. 8 and 9 are schematic diagrams of the vehicle node structure in the embodiment of the invention.

Detailed Description

For better understanding of the scheme of the present invention, a one-dimensional slot state table mechanism, a historical slot state table and a priority service collision mechanism are introduced first.

One-dimensional slot state table mechanism:

the one-dimensional time slot state table mechanism (SU-ALOHA for short) has the same basic idea as the MS-ALOHA mechanism: and the nodes sense the time slot occupation situation of the surrounding nodes by receiving the FI, and generate the FI for transmission according to the maintained latest time slot occupation situation of the surrounding nodes in the self transmission time slot.

The SU-ALOHA mechanism differs from the MS-ALOHA mechanism in that: the MS-ALOHA maintains and senses the timeslot occupation status of the surrounding nodes by using a (N-1) × N-dimensional timeslot status cache table, while the SU-ALOHA stores FI in an iterative manner, that is, the node only stores a vector related to the current occupation status of each timeslot, which is called a timeslot status vector (also called a timeslot status table), a possible timeslot status vector is shown in fig. 5, when the node receives FI sent by other nodes, the timeslot information unit corresponding to each timeslot in the locally stored timeslot status vector is updated according to the timeslot information field corresponding to each timeslot in the newly received FI, timeslot status information corresponding to the timeslot is recorded in each timeslot information unit, and the timeslot status information is maintained by maintaining the timeslot status vector. When a node needs to transmit the FI determined by the node, the FI to be transmitted is generated according to the information in the saved time slot state vector (table).

Preferably, in order to ensure that the timeslot status vector only processes timeslot status information of at most one frame timeslot, timeslot resources can be quickly found and released, and the influence caused by wrong history information can be eliminated. And after the FI is sent by the node, resetting the time slot state information corresponding to the non-self-occupation time slot in the time slot state vector to 00.

When the node has only one sending time slot, only one time slot state vector needs to be maintained inside the node, and when the node has a plurality of sending time slots, 2 time slot state vector maintenance schemes exist, wherein one scheme is to maintain one time slot state vector for each sending time slot, and the scheme is called a multi-table scheme for short; the other is to maintain only one time slot state vector in the node, which is called a single table scheme for short.

The sending time slot of the node comprises a self-occupation time slot and an application time slot. The self-occupation time slot means that the node successfully sends the FI and/or the data packet in the corresponding time slot, and the time slot is the self-occupation time slot from the time when the node occupies the time slot to send the FI and/or the data packet to the time when the node releases the time slot; the application time slot refers to that a node applies for a time slot according to the requirement of high-level service, the time slot is an application time slot before the node successfully sends an FI and/or a data packet in the time slot, and the application time slot becomes the self-occupied time slot of the node after the node successfully sends the FI and/or the data packet in the time slot.

The specific processing method of the multi-table scheme is as follows:

when a node receives FIs sent by other nodes in a receiving time slot, updating a time slot information domain corresponding to each time slot in a time slot state vector corresponding to each sending time slot according to the received time slot state information corresponding to each time slot in the FIs;

when a node reaches each sending time slot, the FI is generated and sent according to each time slot information domain recorded in the time slot state vector of the current sending time slot, wherein the time slot information content of other self-occupied time slots in the FI can be obtained from the time slot state vectors corresponding to the other self-occupied time slots.

And after the FI is sent by the node, clearing the time slot information fields corresponding to the other time slots except the sending time slot in the time slot state vector corresponding to the sending time slot.

The specific processing method of the single-table scheme is as follows:

when a node receives FIs sent by other nodes in a receiving time slot, updating a time slot information domain corresponding to each time slot in a time slot state vector according to the received time slot state information corresponding to each time slot in the FIs;

when the node reaches each sending time slot, the FI is organized and generated according to each time slot information domain recorded in the current time slot state vector and sent.

(II) historical time slot state table:

the method comprises the steps that a node resets a one-dimensional time slot state table after transmitting FI on a transmission time slot, so that the time slot condition of the node known by a non-self-occupation time slot in a frame is incomplete, and only time slot state information of M time slots (M < N, N represents the number of time slots contained in the frame) is obtained, and if the node selects an application time slot according to the incomplete time slot state information, time slot collision is easy to occur; therefore, a concept of a historical time slot state table is proposed, the historical time slot state table indicates a time slot occupation situation of a node in L frames (L is a positive integer, e.g., L =1 or 2, and may also be other values, which is only an example here) before a current frame, and the node selects an application time slot according to time slot state information recorded in the historical time slot state table. The maintenance of the time slot state is a dynamic updating process, which is related to the starting point of the start maintenance, in order to ensure that the historical time slot state table and the time slot state vector are maintained synchronously, the historical time slot state table and the time slot state vector can be associated to the same time slot resource, the time slot resource can be a real sending time slot of a node (when the node actually occupies the time slot) or a virtual sending time slot (when the node does not occupy the time slot), the node resets the time slot state vector at the time slot, updates the historical time slot state table (namely records the time slot occupation condition of the node in L frame time from the current frame), and after the time slot state vector is reset at the time slot, the time slot state vector and the historical time slot state table are continuously updated synchronously according to the received FI.

(III) priority service collision mechanism:

under the SU-ALOHA mechanism, the priority indication domain corresponding to each time slot in FI occupies 2 bits, and can indicate 4 priority levels. The processing principle of the priority mechanism is as follows:

when time slot resources used by a node sending a high-priority service and a node sending a low-priority service collide, the node sending the high-priority service continues to use the time slot resources, the node sending the low-priority service initiates an access process again, the STI of the collided time slot is filled in a maintained time slot state vector by other nodes as the STI of the node sending the high-priority service, and the time slot state is collision;

when the time slot resources used by two nodes sending the same priority service collide, the two nodes release the occupied time slot resources and initiate the access process again, the STI of the collided time slot is filled as the special STI by other nodes in the maintained time slot state vector, and the time slot state is set as collision.

Based on the established application rule, in the embodiment of the present invention, the time slot occupation state information may express four occupation states of the time slot: (00) the time slot is represented as an idle state, (10) the time slot is represented as being occupied by other nodes which are one hop away from the node (for short, occupied by one hop of adjacent nodes) or the node, (11) the time slot is represented as being occupied by other nodes which are two hops away from the node (for short, occupied by two hop of adjacent nodes), (01) the time slot is represented as being occupied by more than two other nodes, namely, a collision state;

referring to fig. 6, in the embodiment of the present invention, a detailed flow of the first node determining that the timeslot resource is collided is as follows:

step 600: and the first node receives FIs sent by other nodes and learns that the other nodes judge that a time slot resource is collided according to the received FIs.

In this embodiment of the present invention, the timeslot resource determined to be collided may be any timeslot in a frame period, and when the first node determines that the timeslot occupation state indicated by the timeslot state information of the timeslot resource is 01 according to FI sent by another node, it is known that another node determines that the timeslot resource is collided.

Step 610: and when the first node determines that the node occupying the time slot resource is a one-hop neighbor node of the first node according to the locally stored time slot state information, the first node judges that the time slot resource is in a collision state.

In the embodiment of the present invention, when determining that the node occupying the time slot resource is a one-hop neighbor node of the first node according to the locally stored time slot state information, the following two methods may be adopted, but are not limited to:

the first mode is as follows: if the first node stores a historical time slot state table, the first node determines the node occupying the time slot resource as a one-hop neighbor node of the first node according to the time slot state information recorded in the historical time slot state table; the historical time slot state table records time slot state information stored in L frames (L is a positive integer, e.g., L =1 or 2) before the current frame by the first node.

For example: and the first node determines the node occupying the time slot resource as a one-hop neighbor node of the first node when knowing that the time slot occupation state corresponding to the time slot resource is 10 according to the time slot state information recorded in the locally stored historical time slot state table.

The second way is: if the first node stores a one-hop neighbor node time slot state table, the first node determines the node occupying the time slot resources as the one-hop neighbor node of the first node according to the node information recorded in the one-hop neighbor node time slot state table; after the first node sends FI and before resetting the timeslot state information corresponding to the non-self-occupation timeslot in the timeslot state vector, the timeslot occupation state stored in the timeslot state table is the node information (e.g., STI of the node) corresponding to the non-self-occupation timeslot occupied by the one-hop neighbor node (i.e., the timeslot occupation state is 10).

For example: the first node directly knows that the node occupying the time slot resource is the one-hop neighbor node of the first node according to the node information recorded in the locally stored one-hop neighbor node time slot state table.

On the other hand, after step 610 is executed, that is, when the first node determines that the timeslot resource is in the collision state, the method updates timeslot status information corresponding to the timeslot resource in a locally maintained timeslot status vector, that is, updates a timeslot occupation state in the timeslot status information to a collision state 10, and specifically includes:

if the first node maintains a corresponding time slot state vector for each sending time slot (that is, a multi-table scheme is adopted to maintain time slot state information), the first node sets the time slot occupation state corresponding to the time slot resource in each maintained time slot state vector as a collision state;

if the first node maintains a unified slot state vector for each transmission slot (i.e., a single table scheme is adopted to maintain the slot state information), the first node sets the slot occupation state corresponding to the slot resource in the maintained unified slot state vector to a collision state.

On the other hand, after step 610 is executed, that is, when the first node determines that the timeslot resource is in the collision state, the timeslot state information corresponding to the timeslot resource in the locally maintained timeslot state vector is updated, that is, the timeslot occupation state in the timeslot state information is updated to the collision state 10, after that, the first node further performs the following operations:

if the first node stores the historical time slot state table, the first node can update the time slot occupation state corresponding to the time slot resource in the maintained historical time slot state table to be a collision state;

if the first node stores the one-hop neighbor node time slot state table, after the first node sends the FI, before resetting the corresponding time slot state information in the non-self-occupation time slot in the time slot state vector (namely resetting to 00), updating the one-hop neighbor node time slot state table according to the node information corresponding to the non-self-occupation time slot occupied by the one-hop neighbor node in the time slot state vector, wherein the time slot occupation state is recorded in the time slot state vector.

The above embodiments are further described in detail with reference to specific application scenarios.

The first scenario is: and the first node acquires the relevant information of the one-hop neighbor node from the historical time slot state table.

Referring to fig. 4, nodes a, b, and c belong to a cluster, that is, a, b, and c can receive FI information transmitted by each other, and assume that node a occupies time slot 7, node b occupies time slot 3, and node c occupies time slot 5, node d is an isolated node (i.e., node d cannot receive FI transmitted by node a, node b, and node c), and node d also occupies time slot 7; assuming that the positions of the node d and the node c are changed, cluster merging is performed, that is, the node d and the node c can receive FI sent by each other, and the priorities of the node a and the node d are the same and are both 00.

For convenience of explanation, it is assumed in this embodiment that a frame has 10 slots, and the slots occupied by each node are as shown in fig. 7.

The specific processing procedure is as follows:

1) before node d and node c perform cluster merging, the slot state vectors of slot 7 of node a, node b and node c in one frame period are shown in table 1:

TABLE 1

As shown in table 1, in the timeslot 7, the timeslot state vector of the node a indicates that the node b occupies the timeslot 3, the node c occupies the timeslot 5, and the timeslot 7 is a self-occupied timeslot of the node a; since the node b just sends FI in the time slot 3 of the same frame period and resets its own time slot state vector, the FI sent by the node c is received in the time slot 5, and since the FI is not sent by the node a at this time, the node b does not know that the node a occupies the time slot 7, the time slot state vector of the node b indicates that the node b occupies the time slot 3, and the node c occupies the time slot 5; since the node c just transmits FI and resets its own slot state vector in slot 5 of the same frame period, the slot state vector of the node c only indicates that the node c occupies slot 5.

The slot state vectors for slot 3 in the next frame period for node a, node b and node c are shown in table 2:

TABLE 2

As shown in table 2, at slot 3, node a sends FI and resets its slot state vector at slot 7 in the previous frame period, so that at this time, only node a is indicated to occupy slot 7 in the slot state vector of slot a; because the node b receives the FI sent by the node a, the time slot state vector of the node b indicates that the node b occupies the time slot 3, the node c occupies the time slot 5, and the time slot a occupies the time slot 7; and node c still does not receive the FI sent by node b, so that only node c is indicated to occupy slot 5 in the slot state vector of node c at this time.

The slot state vectors for node a, node b and node c at slot 5 are shown in table 3:

TABLE 3

As shown in table 3, in time slot 5, node a receives FI transmitted by node b in time slot 3, so that the time slot state vector of node a indicates that node b occupies time slot 3, node c occupies time slot 5, and time slot a occupies time slot 7; since the node b sends FI in the time slot 3 and resets the time slot state vector of the node b, the time slot state vector of the node b only indicates that the node b occupies the time slot 3; since the node c receives the FI transmitted by the node b in the time slot 3, the time slot state vector of the node c indicates that the node b occupies the time slot 3, the node c occupies the time slot 5, and the time slot a occupies the time slot 7.

In this embodiment, it is assumed that the historical timeslot status table and timeslot status vector of each node are both associated with respective transmission timeslots. The states of the historical slot state tables of each of the node a, the node b and the node c at the corresponding transmission slot (i.e., the state before the reset) are as shown in table 4:

TABLE 4

The slot state vector and the historical slot state table for node d at slot 7 are shown in table 5:

TABLE 5

2) After the node d and the node c perform cluster merging, if the node d does not receive the FI sent by the node c, during merging the initial first frame, it is assumed that the slot state vectors of the node a, the node b, the node c, and the node d in the slot 3 are as shown in table 6:

TABLE 6

As shown in table 6, it is assumed that, in merging the initial first frame, the node a has sent FI in slot 7 of the previous frame period and resets its slot state vector, so that only the node a is indicated to occupy slot 7 in the slot state vector of slot a at this time; because the node b receives the FI sent by the node a, the time slot state vector of the node b indicates that the node b occupies the time slot 3, the node c occupies the time slot 5, and the time slot a occupies the time slot 7; and node c still does not receive the FI sent by node b, so that only node c is indicated to occupy slot 5 in the slot state vector of node c at this time.

After receiving the FI sent by the node b, according to the method provided in the embodiment of the present invention, it can be determined that the one-hop neighbor node (i.e., node d) and the two-hop neighbor node (i.e., node a) of the node c collide, and the priorities of the node a and the node d are the same, so that according to the same priority service timeslot resource collision processing mechanism, the timeslot state vectors of the node a, the node b, the node c, and the node d in timeslot 5 are as shown in table 7:

TABLE 7

As shown in table 7, since the node a receives the FI transmitted by the node b in the time slot 3, the time slot state vector of the node a indicates that the node b occupies the time slot 3, the node c occupies the time slot 5, and the time slot a occupies the time slot 7; since the node b sends FI in the time slot 3 and resets the time slot state vector of the node b, the time slot state vector of the node b only indicates that the node b occupies the time slot 3; since the node c receives the FI sent by the node b in the time slot 3, the time slot state vector of the node c indicates that the node b occupies the time slot 3, the node c occupies the time slot 5, the time slot a occupies the time slot 7, and the time slot 7 has resource collision, and since the node d still does not receive the FI sent by the node c, the time slot state vector of the node d only indicates that the node d occupies the time slot 7.

After receiving the FI sent by the node c in the time slot 5, the node d can judge that the self-occupied time slot 7 is collided, and according to the same priority service time slot resource collision processing mechanism, the node d releases the self-occupied time slot 7.

Meanwhile, the historical slot state table of node b at slot 5 is shown in table 8:

TABLE 8

After receiving the FI sent by the node c in the time slot 5, the node b obtains the information that the time slot 7 collides, and the node b checks the historical time slot state table stored by the node b, finds that the time slot 7 has detection domain information and is occupied by the own one-hop neighbor node (i.e. the node a), and then the node b considers that the own one-hop neighbor node and the two-hop neighbor node collide, so that the state of the time slot 7 is updated to be the collision (i.e. the time slot occupation state is 01).

3) In the second frame after cluster combination, when the node b sends FI in the time slot 3, the time slot 7 is indicated to have resource collision (that is, the time slot occupation state is set to 01), after the node a receives the FI information sent by the node b, the node a learns the time slot collision of self sending, and according to the time slot resource collision processing mechanism of the same priority, the node a releases the time slot 7 occupied by the node a.

The second scenario is: and the first node acquires the relevant information of the one-hop neighbor node from the historical time slot state table.

In this embodiment, it is assumed that the topology and the timeslot occupation of the node a, the node b, the node c, and the node d are as shown in fig. 4 and fig. 7, and the priority of the node a is lower than that of the node d, and it is assumed that the priority of the node a is 02 and the priority of the node d is 00,

the specific processing procedure is as follows:

1) before the node d and the node c perform cluster merging, the time slot state vectors and the historical time slot state tables of the node a, the node b and the node c in the time slot 7, the time slot 3 and the time slot 5 are consistent with those in the first scene, and are not described again here.

And the slot state vector and historical slot state table for node d at slot 7 are shown in table 9:

TABLE 9

2) After the node d and the node c perform cluster merging, if the node d does not receive the FI sent by the node c, the slot state vectors of the node a, the node b, the node c, and the node d in the slot 3 in the initial first frame after merging are shown in table 10:

watch 10

As shown in table 10, it is assumed that, in merging the initial first frame, the node a has sent FI in slot 7 of the previous frame period and resets its slot status vector, so that, in the slot status vector of slot a at this time, only the node a is indicated to occupy slot 7 and have a priority of 02 (lower than priority 00); the FI sent by the node a is received by the node b, so that the time slot state vector of the node b indicates that the node b occupies the time slot 3, the node c occupies the time slot 5, the time slot a occupies the time slot 7 and the priority is 02; however, the node c still does not receive the FI sent by the node b, so that at this time, the time slot state vector of the node c only indicates that the node c occupies the time slot 5, the node d occupies the time slot 7, and the priority is 00; node d does not receive FI sent by node c, and therefore, only indicates that node d occupies slot 7 and has a priority of 00 in the slot state vector of node d at this time.

After receiving the FI sent by the node b, the node c may determine that a collision occurs between its own one-hop neighboring node (i.e., node d) and two-hop neighboring node (i.e., node a), and the priority of the node a is lower than that of the node d, and according to the collision processing mechanism of different service time slot resources with different priorities, the time slot state vectors of the node a, the node b, the node c, and the node d in the time slot 5 are shown in table 11:

TABLE 11

As shown in table 11, since node a receives FI transmitted by node b in slot 3, the slot state vector of node a indicates that node b occupies slot 3, node c occupies slot 5, and slot a occupies slot 7 with a priority of 02; since the node b sends FI in the time slot 3 and resets the time slot state vector of the node b, the time slot state vector of the node b only indicates that the node b occupies the time slot 3; because the node c receives the FI sent by the node b in the time slot 3, the time slot state vector of the node c indicates that the node b occupies the time slot 3, the node c occupies the time slot 5, the time slot d occupies the time slot 7, the priority is 00, and the time slot 7 has resource collision; since the node d still does not receive the FI sent by the node c, at this time, the slot state vector of the node d only indicates that the node d occupies the slot 7 and has the priority of 00.

After receiving the FI sent by the node c in the time slot 5, the node d can judge that the time slot 7 occupied by the node d is collided, and according to a time slot resource collision processing mechanism with different priorities, the node d continues to occupy the time slot 7.

The historical slot state table for node b at slot 5 is shown in table 12:

TABLE 12

After receiving the FI sent by the node c in the time slot 5, the node b obtains the information that the time slot 7 collides, and checks the historical time slot state table currently stored by the node b, and finds that the time slot 7 has detection domain information and is occupied by the one-hop neighbor node (i.e., the node a), the node b determines that the one-hop neighbor node and the two-hop neighbor node collide, so that the state of the time slot 7 is updated to be the collision (i.e., the time slot occupation state is set to be 01).

3) In the second frame after cluster combination, when the node b sends FI in the time slot 3, the time slot 7 is indicated to have resource collision (that is, the time slot occupation state is set to 01), after the node a receives the FI information sent by the node b, the node a learns the time slot collision sent by itself, and according to the time slot resource collision processing mechanism of different services with different priorities, the node a releases the time slot 7 occupied by itself.

The third scenario is: and the first node acquires the relevant information of the one-hop neighbor node from the one-hop neighbor node time slot state table.

In this embodiment, the topology and the timeslot occupation of the node a, the node b, the node c, and the node d are all as shown in fig. 4 and fig. 7, and the priorities of the node a and the node d are both 00.

The specific processing procedure is as follows:

1) before node d and node c perform cluster merging, the slot state vectors of node a, node b and node c in slot 7 are shown in table 13:

watch 13

The slot state vectors for node a, node b and node c at slot 3 are shown in table 13:

TABLE 14

The slot state vectors for node a, node b and node c at slot 5 are shown in table 15:

watch 15

After the node a, the node b, and the node c transmit the slot FI, and before the slot state information corresponding to the non-self-occupied slot in the slot state vector is reset to 00, the one-hop neighbor node slot state tables maintained by the node a, the node b, and the node c are respectively shown in table 16, table 17, and table 18:

TABLE 16

TABLE 17

Watch 18

The storage manner of the one-hop neighbor node time slot state table is only an example, and in practical application, other storage manners are not excluded.

The slot state vector for node d at slot 7 is shown in table 19:

watch 19

At this time, the node d does not have the one-hop neighbor node information, and the one-hop neighbor node time slot state table of the node d is empty.

2) After the node d and the node c perform cluster merging, if the node d does not receive the FI sent by the node c, the timeslot state vectors of the node a, the node b, the node c, and the node d in timeslot 3 in the initial first frame after merging are shown in table 20:

watch 20

After receiving the FI sent by the node b, the node c may determine that a one-hop neighbor node (i.e., node d) and a two-hop neighbor node (i.e., node a) of the node c collide with each other, and the priorities of the node a and the node b are the same, and according to the same priority service timeslot resource collision processing mechanism, the timeslot state vectors of the node a, the node b, the node c, and the node d in timeslot 5 are shown in table 21:

TABLE 21

After receiving the FI sent by the node c in the time slot 5, the node d can judge that the time slot 7 occupied by the node d is collided, and according to the same priority service time slot resource collision processing mechanism, the node b releases the time slot 7 occupied by the node b.

The one-hop neighbor node time slot state table of the node b in the time slot 5 is as follows:

TABLE 22

After receiving the FI sent by the node c in the time slot 5, the node b obtains the information that the time slot 7 collides, and the node b checks the state table of the one-hop neighbor node currently stored by the node b, and finds that the time slot 7 is occupied by the one-hop neighbor node (i.e., the node a), the node b determines that the one-hop neighbor node and the two-hop neighbor node collide, thereby updating the state of the time slot 7 to be the collision (i.e., the state of the occupied time slot is set to 01).

3) In the second frame after cluster combination, when the node b sends FI in the time slot 3, the time slot 7 is indicated to have resource collision (i.e. the time slot occupation state is set to 01), after the node a receives the FI sent by the node b, the node a learns that the time slot 7 occupied by itself has sent collision, and according to the same priority service time slot resource collision processing mechanism, the node a releases the time slot 7 occupied by itself.

The above embodiment only exemplifies that the node only occupies one time slot, when the node occupies a plurality of time slots, if a single table scheme is adopted, the information of the self-occupied time slot is added in the above time slot state vector, and the judgment and processing process of the whole time slot collision state is the same as the above embodiment; if a multi-table scheme is adopted, each sending time slot has a time slot state vector, and the judgment and processing process of the time slot collision state of each time slot state vector is the same as the embodiment.

Referring to fig. 8, in an embodiment of the present invention, a vehicle node (e.g., a first node) includes a communication unit 80 and a processing unit 81, wherein,

the communication unit 80 is configured to receive the FI sent by the other node, and learn, according to the received FI, that the other node determines that a time slot resource is collided;

and the processing unit 81 is configured to determine that the time slot resource is in a collision state when determining that the node occupying the time slot resource is a one-hop neighbor node of the vehicle node according to the locally stored time slot state information.

The processing unit 81 determines, according to the locally stored time slot state information, that the node occupying the time slot resource is a one-hop neighbor node of the own vehicle node, and includes:

or,

if the one-hop neighbor node time slot state table is stored, determining the node occupying the time slot resources as the one-hop neighbor node of the vehicle node according to the node information recorded in the one-hop neighbor node time slot state table; after FI is sent by the vehicle node and before time slot state information corresponding to the non-self-occupation time slot in the time slot state vector is reset, the stored time slot occupation state is the node information corresponding to the non-self-occupation time slot occupied by the one-hop neighbor node.

The processing unit 81 is further configured to:

if the historical time slot state table is stored, setting the time slot occupation state corresponding to the time slot resource in the historical time slot state table as a collision state.

The processing unit 81 is further configured to:

and if the one-hop neighbor node time slot state table is stored, after FI is sent, before time slot state information corresponding to the non-self-occupation time slot in the time slot state vector is reset, updating the one-hop neighbor node time slot state table according to the node information corresponding to the non-self-occupation time slot occupied by the one-hop neighbor node in the time slot state vector, wherein the time slot occupation state recorded in the time slot state vector is the one-hop neighbor node time slot.

Referring to fig. 9, in an embodiment of the present invention, a vehicle node (e.g., a first node) includes a communication port 90 and a processor 91, wherein,

the communication port 90 is used for receiving FIs sent by other nodes and learning that the other nodes determine that a time slot resource is collided according to the received FIs;

and the processor 91 is configured to determine that the time slot resource is in a collision state when determining that the node occupying the time slot resource is a one-hop neighbor node of the vehicle node according to the locally stored time slot state information.

The processor 91 determines, according to the locally stored time slot state information, that the node occupying the time slot resource is a one-hop neighbor node of the own vehicle node, including:

or,

The processor 91 is further configured to:

In summary, in the embodiment of the present invention, after the first node receives the FI sent by the other node, if it is known that the other node determines that a time slot resource is collided according to the received FI, the first node determines that the time slot resource is in a collision state when determining, according to the locally stored time slot state information, that the node occupying the time slot resource is a one-hop neighbor node of the first node. Therefore, when the time slot resources in the system collide, the nodes detecting the collision state can timely and effectively transmit the information of the time slot resource collision to the peripheral nodes, so that the nodes using the same time slot resources are effectively prevented from generating strong interference to each other when FI and/or data are transmitted, and meanwhile, the use efficiency of the time slot resources is improved.

As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various modifications and variations can be made in the embodiments of the present invention without departing from the spirit or scope of the embodiments of the invention. Thus, if such modifications and variations of the embodiments of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to encompass such modifications and variations.

Claims

1. A method for determining a slot resource collision, comprising:

the first node receives frame information FI sent by other nodes, and learns that the other nodes judge that a time slot resource is collided according to the received FI;

2. The method of claim 1, wherein the first node determines the node occupying the time slot resource as a one-hop neighbor node of the first node according to locally stored time slot state information, comprising:

or,

3. The method of claim 1 or 2, wherein after the first node determines that the time slot resource is in the collision state, further comprising:

4. The method of claim 3, further comprising:

5. The method of claim 3, further comprising:

6. A vehicle node, comprising:

the communication unit is used for receiving frame information FI sent by other nodes and learning that the other nodes judge that a time slot resource is collided according to the received FI;

7. The vehicle node of claim 6, wherein the processing unit determines the node occupying the time slot resource as a one-hop neighbor node of the vehicle node according to the locally stored time slot status information, and comprises:

or,

8. The vehicle node of claim 6 or 7, wherein the processing unit is further to:

9. The vehicle node of claim 8, wherein the processing unit is further to:

10. The vehicle node of claim 8, wherein the processing unit is further to: