CN109688566B - Multi-channel MAC layer data self-adaptive transmission method, medium and system in Internet of vehicles - Google Patents
Multi-channel MAC layer data self-adaptive transmission method, medium and system in Internet of vehicles Download PDFInfo
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
- H04W4/30—Services specially adapted for particular environments, situations or purposes
- H04W4/40—Services specially adapted for particular environments, situations or purposes for vehicles, e.g. vehicle-to-pedestrians [V2P]
- H04W4/46—Services specially adapted for particular environments, situations or purposes for vehicles, e.g. vehicle-to-pedestrians [V2P] for vehicle-to-vehicle communication [V2V]
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L5/00—Arrangements affording multiple use of the transmission path
- H04L5/003—Arrangements for allocating sub-channels of the transmission path
- H04L5/0053—Allocation of signaling, i.e. of overhead other than pilot signals
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L67/00—Network arrangements or protocols for supporting network services or applications
- H04L67/01—Protocols
- H04L67/12—Protocols specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L69/00—Network arrangements, protocols or services independent of the application payload and not provided for in the other groups of this subclass
- H04L69/26—Special purpose or proprietary protocols or architectures
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W72/00—Local resource management
- H04W72/12—Wireless traffic scheduling
- H04W72/1263—Mapping of traffic onto schedule, e.g. scheduled allocation or multiplexing of flows
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W74/00—Wireless channel access, e.g. scheduled or random access
- H04W74/08—Non-scheduled or contention based access, e.g. random access, ALOHA, CSMA [Carrier Sense Multiple Access]
- H04W74/0808—Non-scheduled or contention based access, e.g. random access, ALOHA, CSMA [Carrier Sense Multiple Access] using carrier sensing, e.g. as in CSMA
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W84/00—Network topologies
- H04W84/18—Self-organising networks, e.g. ad-hoc networks or sensor networks
Abstract
The invention discloses a method, a medium and a system for multi-channel MAC layer data self-adaptive transmission in Internet of vehicles, which comprises the following steps: dividing a channel into a control channel and a service channel based on a MAC layer protocol of a multi-channel operation; dividing the period of the control channel into a broadcasting period and a negotiation period; in a broadcast period, a vehicle node acquires vehicle state information sent by a neighbor vehicle node, and performs self-adaptive adjustment on the total number of MAC frame time slots according to the vehicle state information; a competition type access mechanism is adopted in a negotiation period, so that the vehicle nodes negotiate the use right of the service channel; determining the frame length of each service channel according to the negotiation result; vehicle nodes in the Internet of vehicles transmit service information with high throughput requirement on a service channel and transmit safe service information and control signaling information on a control channel; therefore, the transmission reliability of the safety message is improved, the use fairness of the service channel is ensured, meanwhile, the channel utilization rate is improved, and the throughput requirement of service message transmission is met.
Description
Technical Field
The invention relates to the technical field of vehicle networking, in particular to a multi-channel MAC layer data self-adaptive transmission method, medium and system in the vehicle networking.
Background
Vehicle Ad-hoc Networks (VANETs), also known as car networking, are one of the more accepted solutions in the academic and industrial circles to implement intelligent transportation systems.
In the existing MAC protocol standard of the car networking, a Dedicated Short Range Communication (DSRC) protocol is mainly used, and a binary backoff contention access mechanism based on CSMA/CA is adopted in the MAC layer of the protocol. When the density of the vehicle nodes is high, the vehicle nodes often cannot compete for channel resources and generate a large amount of packet loss. In addition, the hidden termination problem in DSRC causes message collision to be aggravated and communication efficiency to be reduced, and the hidden termination problem greatly reduces network throughput. Thus, the DSRC protocol does not guarantee reliable transmission of safety messages and transmission throughput requirements of service messages in a complex vehicle networking environment.
Disclosure of Invention
The present invention is directed to solving, at least to some extent, one of the technical problems in the art described above. Therefore, an object of the present invention is to provide a method for adaptively transmitting data on a multi-channel MAC layer in an internet of vehicles, which can improve the transmission reliability of a safety message, ensure the fairness in use of a service channel, and improve the utilization rate of the channel to meet the transmission throughput requirement of the service message.
A second object of the invention is to propose a computer-readable storage medium.
The third purpose of the invention is to provide a vehicle networking system.
In order to achieve the above object, an embodiment of a first aspect of the present invention provides a method for adaptive transmission of multichannel MAC layer data in an internet of vehicles, including the following steps: dividing a channel into a control channel and a plurality of service channels based on a MAC layer protocol of multi-channel operation; dividing the period of the control channel into a broadcasting period and a negotiation period; in a broadcast period, each vehicle node which has access to a channel acquires vehicle state information sent by a neighbor vehicle node, and performs self-adaptive adjustment on the total number of MAC frame time slots of the vehicle node according to the vehicle state information; a competitive access mechanism is adopted in the negotiation period, so that the vehicle nodes negotiate the use right of the service channel through a multi-handshake protocol; determining the frame length of each service channel according to the negotiation result of the negotiation period; and vehicle nodes in the Internet of vehicles transmit service information with high throughput requirement according to the service channel with the determined frame length, and transmit delay sensitive safety service information and control signaling information according to the control channel.
The multi-channel MAC layer data self-adaptive transmission method in the Internet of vehicles comprises the following steps: dividing a channel into a control channel and a plurality of service channels based on a MAC layer protocol of multi-channel operation; dividing the period of the control channel into a broadcasting period and a negotiation period; in a broadcast period, each vehicle node which has access to a channel acquires vehicle state information sent by a neighbor vehicle node, and performs self-adaptive adjustment on the total number of MAC frame time slots of the vehicle node according to the vehicle state information; a competitive access mechanism is adopted in the negotiation period, so that the vehicle nodes negotiate the use right of the service channel through a multi-handshake protocol; determining the frame length of each service channel according to the negotiation result of the negotiation period; vehicle nodes in the Internet of vehicles transmit service information with high throughput demand according to a service channel with determined frame length, and transmit delay-sensitive safety service information and control signaling messages according to a control channel; therefore, the transmission reliability of the safety message is improved, the use fairness of the service channel is ensured, and meanwhile, the utilization rate of the channel is improved so as to meet the transmission throughput requirement of the service message.
In addition, the method for adaptively transmitting the multichannel MAC layer data in the internet of vehicles according to the embodiment of the present invention may further have the following additional technical features:
optionally, in the broadcast period, the method further includes: a vehicle node to be accessed into a channel monitors the period of at least one control channel of the channel, acquires vehicle state information sent by a neighbor vehicle node, and acquires time slot occupation information in a two-hop communication range according to the vehicle state information sent by the neighbor vehicle node; and the vehicle node to be accessed into the channel randomly selects an idle time slot to be accessed into the channel according to the time slot occupation information, and periodically sends the state information of the vehicle per se on the accessed time slot.
Optionally, the vehicle state information includes vehicle identification information, occupied time slot information, available time slot values, total number of frame time slots, neighbor information, and safety information.
Optionally, the adaptively adjusting the total number of the MAC frame time slots according to the vehicle state information includes: judging whether the available time slot value per se is smaller than a preset minimum time slot threshold value or not according to vehicle state information sent by the neighbor vehicle node; if so, increasing the frame time slot of the vehicle node; if not, further judging whether the self available time slot value is larger than or equal to a preset maximum time slot threshold value; and if so, recovering the frame time slot of the vehicle node, which is larger than the minimum time slot threshold value.
Optionally, when the frame time slot of the vehicle node is recovered, whether the vehicle node occupies the frame time slot to be recovered is also judged; if yes, the vehicle node is switched to other available time slots in the period of the next control channel, and the frame time slot to be recovered is recovered after the switching is completed.
Optionally, the vehicle node negotiates the right to use the service channel through a multiple handshake protocol, including: and the vehicle node sends a service request to other vehicle nodes in the Internet of vehicles in the negotiation period according to the competitive access mechanism, so that the other vehicle nodes respond to the service request, generate a negotiation result according to the response result when receiving the response result, and broadcast the negotiation result.
Optionally, each of said vehicle nodes is equipped with a half-duplex transceiver to alternately switch operation between said control channel and said service channel.
Optionally, the control channel has a period of 100 ms.
In order to achieve the above object, a second embodiment of the present invention provides a computer-readable storage medium, on which an implementation program of a multi-channel MAC data adaptive transmission method in an internet of vehicles is stored, and when the implementation program of the multi-channel MAC data adaptive transmission method in the internet of vehicles is executed by a processor, the multi-channel MAC data adaptive transmission method in the internet of vehicles is implemented.
In order to achieve the above object, an embodiment of a third aspect of the present invention provides a vehicle networking system, which includes a plurality of vehicle nodes, and data transmission is performed between the vehicle nodes based on an adaptive multi-channel MAC layer frame structure, where an implementation apparatus of the multi-channel MAC layer data transmission method includes: the protocol stack module is used for dividing a channel into a control channel and a plurality of service channels based on an MAC layer protocol of multi-channel operation, and dividing the period of the control channel into a broadcasting period and a negotiation period, wherein the negotiation period adopts a competitive access mechanism; the service processing module is used for processing different types of service messages and sending corresponding message sending or receiving requests to the control module; the multi-channel transceiver module is used for the node to send or receive messages; transmitting vehicle state information in a control channel broadcast period and acquiring the vehicle state information transmitted by a neighbor vehicle node; sending or receiving a control signaling message in a control channel negotiation period; transmitting or receiving a service type message on a service channel; (ii) a The control module is used for adaptively adjusting the total number of the MAC frame time slots of the vehicle nodes according to the vehicle state information and carrying out a multi-time handshake protocol through the multi-channel transceiver module in a negotiation period so as to negotiate the use right of a service channel; the control module is further configured to determine a frame length of each service channel according to a negotiation result of the negotiation period.
The vehicle networking system comprises a plurality of vehicle nodes, and data transmission is carried out between the vehicle nodes based on a self-adaptive multichannel MAC layer frame structure, wherein an implementation device of the multichannel MAC layer data transmission method comprises the following steps: the protocol stack module is used for dividing a channel into a control channel and a plurality of service channels based on an MAC layer protocol of multi-channel operation, and dividing the period of the control channel into a broadcasting period and a negotiation period, wherein the negotiation period adopts a competitive access mechanism; the service processing module is used for processing different types of service messages and sending corresponding message sending or receiving requests to the control module; the multi-channel transceiver module is used for the node to send or receive messages; transmitting vehicle state information in a control channel broadcast period and acquiring the vehicle state information transmitted by a neighbor vehicle node; sending or receiving a control signaling message in a control channel negotiation period; transmitting or receiving a service type message on a service channel; (ii) a The control module is used for adaptively adjusting the total number of the MAC frame time slots of the vehicle nodes according to the vehicle state information and carrying out a multi-time handshake protocol through the multi-channel transceiver module in a negotiation period so as to negotiate the use right of a service channel; the control module is also used for determining the frame length of each service channel according to the negotiation result of the negotiation period; therefore, the transmission reliability of the safety message is improved, the use fairness of the service channel is ensured, and meanwhile, the utilization rate of the channel is improved so as to meet the transmission throughput requirement of the service message.
Drawings
Fig. 1 is a schematic flow chart of a method for adaptively transmitting multi-channel MAC layer data in an internet of vehicles according to an embodiment of the present invention;
fig. 2 is a schematic flow chart of a method for adaptive transmission of multichannel MAC layer data in the internet of vehicles according to another embodiment of the present invention;
FIG. 3 is a schematic diagram of a frame structure of a MAC layer of the Internet of vehicles according to an embodiment of the invention;
FIG. 4 is a schematic diagram of a vehicle networking network topology and vehicle node timeslot occupancy in accordance with an embodiment of the present invention;
FIG. 5 is a schematic diagram of a vehicle status information transmission format according to an embodiment of the present invention;
FIG. 6 is a diagram illustrating a process of a vehicle node negotiating a usage right of a service channel according to an embodiment of the present invention;
fig. 7 is a schematic structural diagram of an apparatus for implementing multi-channel MAC layer data adaptive transmission in an internet of vehicles system according to an embodiment of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
In the existing MAC protocol of the vehicle networking, a DSRC protocol is mostly adopted, and the protocol cannot ensure the reliable transmission of safety messages and the transmission throughput requirement of service messages in a complex vehicle networking environment; the multi-channel MAC layer data self-adaptive transmission method in the Internet of vehicles comprises the following steps: dividing a channel into a control channel and a plurality of service channels based on a MAC layer protocol of multi-channel operation; dividing the period of the control channel into a broadcasting period and a negotiation period; in a broadcast period, each vehicle node which has access to a channel acquires vehicle state information sent by a neighbor vehicle node, and performs self-adaptive adjustment on the total number of MAC frame time slots of the vehicle node according to the vehicle state information; a competitive access mechanism is adopted in the negotiation period, so that the vehicle nodes negotiate the use right of the service channel through a multi-handshake protocol; determining the frame length of each service channel according to the negotiation result of the negotiation period; vehicle nodes in the Internet of vehicles transmit service information with high throughput demand according to a service channel with determined frame length, and transmit delay-sensitive safety service information and control signaling messages according to a control channel; therefore, the transmission reliability of the safety message is improved, the use fairness of the service channel is ensured, and meanwhile, the utilization rate of the channel is improved so as to meet the transmission throughput requirement of the service message.
In order to better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
In order to better understand the technical solution, the technical solution will be described in detail with reference to the drawings and the specific embodiments.
Fig. 1 is a schematic flow chart of a method for adaptively transmitting multichannel MAC layer data in an internet of vehicles according to an embodiment of the present invention, and as shown in fig. 1, the method for adaptively transmitting multichannel MAC layer data in an internet of vehicles includes the following steps:
the channel is divided into a control channel and a plurality of service channels based on the MAC layer protocol of the multi-channel operation S101.
That is, the MAC layer protocol based on the multi-channel operation divides a channel to divide the channel into one control channel and a plurality of service channels, so that different types of messages are transmitted through the control channel and the service channels.
As an example, the channel is divided into one control channel for transmitting the delay-sensitive security traffic information and the control signaling information and six service channels for transmitting the traffic information with high throughput requirement.
In some embodiments, to ensure the transmission of information, each vehicle node is equipped with a half-duplex transceiver to alternately switch between control and service channels and transmit corresponding safety traffic information, control signaling messages, and high throughput-demand traffic information.
In some embodiments, the control channel has a period of 100 ms.
S102, dividing the period of the control channel into a broadcast period and a negotiation period.
That is, the period of the control channel is further divided into a broadcasting period and a negotiation period, so as to divide the periods in which the vehicle nodes broadcast the vehicle state information, broadcast the safety service information, negotiate the use right of the service channel, and the like.
As an example, the broadcast period employs a tdma (time division multiple access) time division multiple access mechanism, so that each vehicle node that has accessed the internet of vehicles can obtain a time slot to periodically broadcast the vehicle status information and the safety service information; the negotiation period adopts a competitive access mechanism, so that each vehicle node which has accessed the Internet of vehicles can negotiate the service channel use right in the negotiation period.
S103, in a broadcast period, each vehicle node which has access to the channel acquires vehicle state information sent by the neighbor vehicle node, and self-adaptive adjustment of the total number of the MAC frame time slots of the vehicle node is carried out according to the vehicle state information.
That is to say, in a broadcast period, each vehicle node having access to a channel receives vehicle state information sent by a neighboring vehicle node, and after the vehicle state information is acquired, determines the traffic condition of the vehicle node, so as to adaptively adjust the total number of the MAC frame time slots of the vehicle node according to the traffic condition of the vehicle node, thereby improving the flexibility of the MAC layer of the internet of vehicles.
Wherein the total number of frame slots refers to the total number of slots of the broadcast period in the vehicle node frame structure.
And S104, adopting a competitive access mechanism in the negotiation period so that the vehicle nodes negotiate the use right of the service channel through a multi-handshake protocol.
That is, the negotiation period employs a contention-based access mechanism, so that the vehicle node can negotiate the usage rights of the service channel through a multiple-handshake protocol within the negotiation period.
As an example, a contention-based access mechanism based on binary backoff is adopted in a negotiation period, when the negotiation period starts, a vehicle node which needs to initiate a service request randomly selects a random number from a preset backoff number set, and broadcasts the service request when the random number is reduced to 0; therefore, other vehicle nodes can receive the service request, judge whether the service request can be met by the other vehicle nodes, and send response results to the vehicle node corresponding to the service request in the binary backoff mode when the judgment result is yes; then, the vehicle node initiating the service request may generate a negotiation result according to the received response result to complete the negotiation process of the service channel usage right.
And S105, determining the frame length of each service channel according to the negotiation result of the negotiation period.
That is, after the vehicle node determines the negotiation result in the negotiation period, the frame length of the service channel is determined according to the negotiation result, so that the channel resource of the service channel can be fully utilized, the channel utilization rate is improved, and the throughput requirement of the service business information is met.
And S106, the vehicle nodes in the Internet of vehicles transmit the service information with high throughput requirement according to the service channel with the determined frame length, and transmit the time delay sensitive safety service information and the control signaling message according to the control channel.
As an example, fig. 3 is a schematic diagram of an MAC layer structure of an internet of vehicles according to an embodiment of the present invention, as shown in fig. 3, a synchronization interval is a period of a control channel, the period of the control channel is divided into a broadcast period and a negotiation period, and each vehicle node sends a REQ \ ACK \ RES negotiation message in the negotiation period to negotiate a right of use of a service channel, where the channel is divided into one control channel and multiple service channels, so as to transmit delay-sensitive security traffic information and control signaling messages through the control channel, and transmit traffic information with high throughput requirement through the service channel.
In summary, the method for adaptively transmitting data of a multi-channel MAC layer in an internet of vehicles according to the embodiment of the present invention includes the following steps: dividing a channel into a control channel and a plurality of service channels based on a MAC layer protocol of multi-channel operation; dividing the period of the control channel into a broadcasting period and a negotiation period; in a broadcast period, each vehicle node which has access to a channel acquires vehicle state information sent by a neighbor vehicle node, and performs self-adaptive adjustment on the total number of MAC frame time slots of the vehicle node according to the vehicle state information; a competitive access mechanism is adopted in the negotiation period, so that the vehicle nodes negotiate the use right of the service channel through a multi-handshake protocol; determining the frame length of each service channel according to the negotiation result of the negotiation period; vehicle nodes in the Internet of vehicles transmit service information with high throughput demand according to a service channel with determined frame length, and transmit delay-sensitive safety service information and control signaling messages according to a control channel; therefore, the transmission reliability of the safety message is improved, the use fairness of the service channel is ensured, and meanwhile, the utilization rate of the channel is improved so as to meet the transmission throughput requirement of the service message.
Fig. 2 is a schematic flow chart of a method for adaptive transmission of multichannel MAC layer data in an internet of vehicles according to another embodiment of the present invention, and as shown in fig. 2, the method for adaptive transmission of multichannel MAC layer data in an internet of vehicles includes the following steps:
s201, the channel is divided into a control channel and a plurality of service channels based on the MAC layer protocol of the multi-channel operation.
S202, dividing the period of the control channel into a broadcast period and a negotiation period.
The above steps are the same as the steps of the method for adaptively transmitting multi-channel MAC layer data in the car networking described in fig. 1, and are not described herein again.
S203, in the broadcast period, the vehicle node to be accessed to the channel monitors the period of at least one control channel of the channel, acquires the vehicle state information sent by the neighbor vehicle node, and acquires the time slot occupation information in the two-hop communication range according to the vehicle state information sent by the neighbor vehicle node.
S204, the vehicle node to be accessed into the channel randomly selects an idle time slot to be accessed into the channel according to the time slot occupation information, and periodically sends the state information of the vehicle per se on the accessed time slot.
That is to say, when a vehicle node needs to access a channel, the channel needs to be monitored for a period of controlling the channel, so that, in the process of sending vehicle state information on the respective acquired time slots by the neighboring vehicle nodes, the vehicle node to be accessed into the channel can acquire the vehicle state information sent by the neighboring vehicle nodes, and further acquire time slot occupation information in a two-hop communication range according to the vehicle state information sent by the neighboring vehicle nodes, and after acquiring the time slot occupation information in the two-hop communication range, an idle time slot access channel is randomly selected according to the occupation situation of the time slot, so that the vehicle state information is periodically sent on the time slot after the channel is accessed.
In some embodiments, the vehicle state information includes, but is not limited to, vehicle identification information, occupied time slot information, available time slot values, total number of frame time slots, neighbor information, and security information; the vehicle identification information refers to a unique identifiable tag of a vehicle and is used for distinguishing each vehicle node, a time slot occupied by the current vehicle node and indicated by the time slot information is occupied, the available time slot value refers to the number of idle time slots in a frame time slot of the current vehicle node, and the total number of the frame time slots refers to the total number of the frame time slots of the current vehicle node. Therefore, after the vehicle node to be accessed to the channel acquires the vehicle state information sent by the neighbor vehicle node, the time slot occupation information in the two-hop communication range can be acquired according to the vehicle state information sent by the neighbor vehicle node, and then the idle time slot in the two-hop communication range is selected for access; the neighbor information is used for indicating that the time slot occupation information of the neighbor vehicle node in the two-hop communication range and the neighbor node corresponding to the vehicle identification information are one-hop nodes or two-hop nodes; the safety information refers to safety indication information which is used for broadcasting to other vehicle nodes when necessary, so that the other vehicle nodes can make corresponding decisions, such as braking, changing a journey and the like, according to the safety information when receiving the safety information.
As an example, as shown in fig. 4, the diagram is a schematic diagram of a car networking network topology and time slot occupation of vehicle nodes, where, taking a vehicle node with a vehicle number of 1 in the diagram as an example, the total number of vehicle frame time slots is 9, the number of available time slots is 4 (i.e., the number of idle time slots occupied by no vehicle node currently), and the occupied time slot is 3rd time slot; for the vehicle node with the vehicle number 1, the vehicle nodes with the vehicle numbers 2 and 3 are neighboring vehicle nodes thereof, the vehicle nodes with the vehicle numbers 4, 7, 8 and 9 are two-hop neighboring vehicle nodes thereof, and after receiving and analyzing the vehicle state information sent by the vehicle nodes with the vehicle numbers 2 and 3, the vehicle node with the vehicle number 1 can acquire the time slot occupation information of the vehicle nodes with the vehicle numbers 4, 7, 8 and 9 in the broadcast period, that is, the vehicle node with the vehicle number 1 can acquire the time slot occupation condition in the two-hop communication range through the vehicle state information sent by the neighboring vehicle nodes.
It should be noted that, in order to ensure that message transmission between vehicle nodes in the network does not collide, initially, it may be defined that the number of frame slots of all vehicle nodes in the two-hop communication range is equal to and equal to the maximum number of frame slots owned in the two-hop communication range in the vehicle networking network; namely Ntsi＝max{Nts1,Nts2,…,Ntsi,…,NtsKIn which N istsiAnd K represents the total K vehicle nodes in the current two-hop communication range.
S205, each vehicle node which has access to the channel acquires the vehicle state information sent by the neighbor vehicle node.
That is, each vehicle node having access to the channel receives the vehicle state information transmitted by the neighboring vehicle node, so as to determine the traffic condition and other information of the vehicle node according to the vehicle state information.
As an example, as shown in fig. 5, the vehicle state information may include vehicle identification information, occupied time slot information (N)basic) Available slot value (N)ava) Total number of frame slots (N)ts) Time slot occupation information and safety information of the neighbor vehicle nodes; the ID represents vehicle identification information to distinguish each vehicle node by vehicle ID, ID + Nrcmd refers to a suggested time slot for suggesting and guiding a time slot conversion behavior of the vehicle node, for example, when the internet of vehicles needs to recover a frame time slot of the vehicle node, the vehicle node occupying the frame time slot to be recovered may select an available time slot according to the ID + Nrcmd bit if the frame time slot to be recovered is occupied by the vehicle node; the time slot occupation information of the neighbor vehicle node includes ID information of the neighbor vehicle node and occupation time slot information (N) of the neighbor vehicle nodebasic) And state information S _ slot of occupied time slots, preferably, when the value of S _ slot is 0, the occupied time slot of the neighbor vehicle node is occupied by the one-hop neighbor vehicle node of the vehicle node, and when the value of S _ slot is 1, the occupied time slot of the neighbor vehicle node is occupied by the two-hop neighbor vehicle node of the vehicle node. The safety information is safety indication information which is used for broadcasting to inform other vehicle nodes when necessary, so that the other vehicle nodes can make corresponding decisions, such as braking, changing a journey and the like, according to the safety information when receiving the safety information.
S206, judging whether the available time slot value per se is smaller than a preset minimum time slot threshold value according to the vehicle state information sent by the neighbor vehicle node; if yes, go to step S207, otherwise go to step S208.
And S207, increasing the frame time slot of the vehicle node, and continuing to execute the step S210.
S208, determine whether the available timeslot value is greater than or equal to the preset maximum timeslot threshold, if so, execute step S209.
S209, recovering the frame time slot of the vehicle node which is larger than the minimum time slot threshold value.
That is, a minimum time slot threshold and a maximum time slot threshold are preset in the internet of vehicles, and whether the number of the MAC frame time slots of the vehicle node is properly set is judged according to the vehicle state information received by the vehicle node and sent by the neighboring vehicle node, so as to adjust the frame time slots of the vehicle node according to different situations.
As an example, first, the preset minimum timeslot threshold is NthreN with twice the maximum slot thresholdthreThen, when the available time slot value of the ith vehicle node is NavaiThen, judge NavaiWhether or not less than NthreAnd is in Navai＜NthreIncreasing the number of frame time slots of the ith vehicle node to ensure that the available time slot value is not less than Nthre(ii) a Then, if N isavaiGreater than NthreThen further judge NavaiWhether or not to be more than or equal to twice NthreIf N is presentavai≥2NthreAnd recovering the frame time slot of the ith vehicle node to improve the time slot utilization rate.
In some embodiments, in order to prevent message collision of each vehicle node in the process of recovering a frame time slot, in the method for adaptive transmission of multi-channel MAC layer data in an internet of vehicles according to an embodiment of the present invention, when recovering a frame time slot of a vehicle node, it is further determined whether a vehicle node occupies the frame time slot to be recovered, and when the determination result is yes, the vehicle node is converted to another available time slot in the next control channel period, and the frame time slot to be recovered is recovered after the conversion action is completed.
As an example, as shown in fig. 4, taking a vehicle node with a vehicle number of 3 in the figure as an example, a minimum timeslot threshold preset in the current internet of vehicles is 3, a maximum timeslot threshold is 6, the number of available timeslots of the vehicle node with the vehicle number of 3 is 6, and the internet of vehicles determines that the number of available timeslots of the vehicle node with the vehicle number of 3 is equal to the maximum timeslot threshold, at this time, the frame timeslot of the vehicle node with the vehicle number of 3 should be recycled to improve the timeslot utilization; whether the three time slots to be recovered, namely 7th time slot, 8th time slot and 9th time slot, are occupied by the vehicle node is further judged, and it can be understood that the frame time slot to be recovered in the vehicle node with the vehicle number of 3 is not occupied by the vehicle node, the frame time slot to be recovered is directly recovered; if a vehicle node occupies a current frame time slot to be recovered, the vehicle node can be proposed to perform time slot conversion in the period of the next control channel so as to convert the frame time slot to an available time slot, as shown in fig. 5, the available time slot can be obtained through an ID + Nrcmd bit in the vehicle state information, so that the vehicle node performs time slot conversion; and the frame time slot to be recovered is recovered after the conversion action is completed.
S210, a competitive access mechanism is adopted in the negotiation period, so that the vehicle nodes negotiate the use right of the service channel through a multi-handshake protocol.
That is, the negotiation period employs a contention-based access mechanism, so that the vehicle node can negotiate the usage rights of the service channel through a multiple-handshake protocol within the negotiation period.
As an example, as shown in fig. 6, during the negotiation period, each vehicle node transmits a signaling message required for contending for a channel resource using a backoff mechanism of dcf (distributed coordination function) for negotiating the use right of the service channel, when the vehicle node A needs service, the vehicle node A sends a service request to other vehicle nodes in the Internet of vehicles by broadcasting a REQ (request) message, so that other vehicle nodes in the internet of vehicles (vehicle nodes B, C, D and E) after receiving the REQ message broadcast by vehicle node a, judging whether the self can meet the service request of the vehicle node A, after the judgment, the vehicle node C and the vehicle node D acquire that the self meets the service request of the vehicle node A, the vehicle node C and the vehicle node D reply ACK (correct acknowledgement) messages to the vehicle node a to indicate that the corresponding service can be provided for the vehicle node a; then, the vehicle node a determines a final negotiation result according to the received multiple ACK messages to determine to receive a response result from the vehicle node D, sends the RES message to the vehicle node D to determine to receive the service from the vehicle node D, and broadcasts the RES message to inform other vehicle nodes in the internet of vehicles of the negotiation result.
S211, determining the frame length of each service channel according to the negotiation result of the negotiation period.
That is, after the negotiation result is determined, the frame length of the service channel is determined according to the negotiation result.
As an example, when each vehicle node is a mechanism that transmits a negotiation message using binary backoff contention, the frame length of the service channel may vary according to different negotiation results, and based on the fact that the formula T may be usedSCH＝TSyncInterval-(Nts*tdua1+DΣ*tdua2) Performing a service channel frame length calculation, wherein TSyncIntervalIndicating the period length, t, of a control channeldua1And tdua2Respectively indicating the time slot widths of a broadcast period and a negotiation period in a period of a control channel; dΣ＝DREQ+DACK+DRESThe obtained value is used for representing the sum of backoff numbers required by the nodes before sending REQ \ ACK \ RES messages in the negotiation process based on binary backoff, so that the frame length of the service channel can be determined according to different negotiation results, and the throughput of the service channel in the Internet of vehicles is improved.
It should be noted that, since the vehicle node uses the service mode of point-to-point communication on the service channel, after the vehicle completes the negotiation, the transceiver may be switched to the corresponding service channel frequency channel to transmit the service information.
S212, the vehicle nodes in the Internet of vehicles transmit the service information with high throughput requirement according to the service channel with the determined frame length, and transmit the time delay sensitive safety service information and the control signaling message according to the control channel.
That is, after the negotiation result is determined according to the negotiation period, the frame length of the service channel is determined according to the negotiation result, and then the vehicle node can transmit the service information with high throughput demand according to the service channel with the determined frame length, and meanwhile, when the control channel performs the next period, the vehicle node performs transmission of the safety service information and the control signaling message on the time slot of the vehicle node.
In summary, according to the method for adaptively transmitting data of a multi-channel MAC layer in an internet of vehicles according to the embodiment of the present invention, first, a channel is divided into a control channel and a plurality of service channels based on a MAC layer protocol of multi-channel operation; then, dividing the period of the control channel into a broadcasting period and a negotiation period; then, in a broadcast period, a vehicle node to be accessed to a channel monitors the period of at least one control channel of the channel, acquires vehicle state information sent by a neighbor vehicle node, and acquires time slot occupation information in a two-hop communication range according to the vehicle state information sent by the neighbor vehicle node; then, the vehicle node to be accessed into the channel randomly selects an idle time slot to be accessed into the channel according to the time slot occupation information, and periodically sends the state information of the vehicle per se on the accessed time slot; then, each vehicle node which has access to the channel acquires vehicle state information sent by a neighbor vehicle node; then, judging whether the self available time slot value is smaller than a preset minimum time slot threshold value according to the vehicle state information sent by the neighbor vehicle node; if so, increasing the frame time slot of the vehicle node; if not, further judging whether the available time slot value per se is larger than or equal to a preset maximum time slot threshold value, and if so, recovering the frame time slot of the vehicle node; then, a competitive access mechanism is adopted in a negotiation period, so that the vehicle nodes negotiate the use right of the service channel through a multi-time handshake protocol; then, determining the frame length of each service channel according to the negotiation result of the negotiation period; then, vehicle nodes in the Internet of vehicles transmit service information with high throughput demand according to a service channel with determined frame length, and transmit delay-sensitive safety service information and control signaling information according to a control channel; therefore, the transmission reliability of the safety message is improved, the use fairness of the service channel is ensured, and meanwhile, the utilization rate of the channel is improved so as to meet the transmission throughput requirement of the service message.
In order to implement the foregoing embodiment, an embodiment of the present invention further provides a computer-readable storage medium, on which an implementation program of a multi-channel MAC data adaptive transmission method in an internet of vehicles is stored, where the implementation program of the multi-channel MAC data adaptive transmission method in the internet of vehicles is executed by a processor to implement the multi-channel MAC layer data adaptive transmission method in the internet of vehicles as described above.
In order to implement the foregoing embodiment, as shown in fig. 7, an embodiment of the present invention further provides a vehicle networking system, where the vehicle networking system includes a plurality of vehicle nodes, and data transmission is performed between the vehicle nodes based on an adaptive multi-channel MAC layer frame structure, where an implementation apparatus of the multi-channel MAC layer data transmission method includes:
a protocol stack module 10, configured to divide a channel into a control channel and multiple service channels based on a MAC layer protocol of a multi-channel operation, and divide a period of the control channel into a broadcast period and a negotiation period;
that is, the protocol stack module 10 is configured to divide the data transmission channel based on the MAC layer protocol of the multi-channel operation, to divide the data transmission channel into one control channel and a plurality of service channels, and further, to divide the period of the control channel into a broadcast period and a negotiation period, wherein the negotiation period employs a contention-based access mechanism.
As an example, the protocol stack module 10 has physical layer functions such as modulation/demodulation, and MAC layer data framing/deframing functions; thus, the protocol stack module 10 can divide the channel into a control channel and a plurality of service channels, and further divide the period of the control channel on the basis of the control channel, so as to divide the period of the control channel into a broadcast period and a negotiation period; wherein, the period of each control channel is preferably 100 ms; meanwhile, the protocol stack module 10 may also determine a broadcast period, a negotiation period, and a mechanism adopted by a service channel; for example, the mechanism of the broadcast period and the service channel may be determined by the protocol stack module 10 as adopting a TDMA mechanism, and the negotiation period may be determined as adopting a CSMA/CA binary back-off contention transmission mechanism.
The service processing module 20 divides services in the internet of vehicles into real-time services and non-real-time services, and the service processing module 20 is configured to process different types of service messages and send corresponding message sending or receiving requests to the control module 40.
A multi-channel transceiver module 30, configured to send or receive a message by a node; transmitting vehicle state information in a control channel broadcast period and acquiring the vehicle state information transmitted by a neighbor vehicle node; sending or receiving a control signaling message in a control channel negotiation period; a service type message is transmitted or received on a service channel.
That is, the multi-channel transceiving module 30 is configured such that the vehicle node transmits its own vehicle state information and acquires vehicle state information transmitted by a neighboring vehicle node through the multi-channel transceiving module 30 in a broadcast period, and transmits or receives a control signaling message in a negotiation period of a control channel and transmits or receives a service type message in a service channel.
As an example, the multi-channel transceiver module 30 is a half-duplex transceiver because the vehicle node needs to switch between different channels to receive different types of information; therefore, the channel switching is carried out through a half-duplex transceiver, so that when the half-duplex transceiver works in a control channel, the state information and the safety service information from the neighbor vehicle node are received in a broadcasting period, and the control signaling message is received and sent in a negotiation period; and, when one half-duplex transceiver is operating in the service channel, performing point-to-point communication with other vehicle nodes for transmission of service messages.
The control module 40 is used for adaptively adjusting the total number of the MAC frame time slots of the vehicle nodes according to the vehicle state information and sending a multi-time handshake protocol message through the multi-channel transceiver module in a negotiation period so as to negotiate the use right of a service channel;
that is, the control module 40 is configured to analyze the vehicle state information received by the vehicle node, and generate a decision according to the vehicle state information to adaptively adjust the total number of MAC frame timeslots of the vehicle node itself, and transmit and receive control signaling messages through the multi-channel transceiver module 30 in the negotiation period, so that a plurality of vehicle nodes negotiate the usage right of the service channel in the negotiation period.
As an example, after receiving the vehicle state information sent by the neighboring vehicle node through the multi-channel transceiver module 30, the protocol stack module 10 sends the vehicle state information to the control module 40, so that the control module 40 generates a corresponding decision according to the received vehicle state information, and receives and sends the control signaling message according to the decision, thereby achieving the purpose of adaptively adjusting the total number of MAC frame slots of the vehicle node according to the vehicle state information, and receiving and sending the control signaling message according to the corresponding decision in the negotiation period.
The control module 40 is further configured to determine a frame length of each service channel according to a negotiation result of the negotiation period;
that is, the control module 40 also makes a determination of the frame length of each service channel according to the negotiation result of the negotiation period.
As an example, the multi-channel transceiver module 30 is further configured to perform the transmission of the traffic information with high throughput requirement through the service channel with the frame length determined by the control module 40, and when the multi-channel transceiver module 30 operates on the control channel, the multi-channel transceiver module 30 performs the transmission of the delay-sensitive safety traffic information and the control signaling message through the control channel.
As an example, after the control module 40 obtains the negotiation result of the negotiation period, the length of the service channel frame corresponding to the service information transfer behavior required by the current vehicle node and the number of time slots corresponding to the service information transfer behavior may be determined, so as to transfer the service information according to the determination result of the control module 40.
It should be noted that the above description about the multi-channel MAC layer data adaptive transmission method in the car networking system in fig. 1 and fig. 2 is also applicable to the car networking system, and is not repeated herein.
In summary, the vehicle networking system according to the embodiment of the present invention includes a plurality of vehicle nodes, and data transmission is performed between the vehicle nodes based on a self-adaptive multi-channel MAC layer frame structure, wherein an implementation apparatus of the multi-channel MAC layer data transmission method includes: the protocol stack module is used for dividing a channel into a control channel and a plurality of service channels based on an MAC layer protocol of multi-channel operation, and dividing the period of the control channel into a broadcasting period and a negotiation period, wherein the negotiation period adopts a competitive access mechanism; the service processing module is used for processing different types of service messages and sending corresponding message sending or receiving requests to the control module; the multi-channel transceiver module is used for the node to send or receive messages; transmitting vehicle state information in a control channel broadcast period and acquiring the vehicle state information transmitted by a neighbor vehicle node; sending or receiving a control signaling message in a control channel negotiation period; transmitting or receiving a service type message on a service channel; the control module is used for adaptively adjusting the total number of the MAC frame time slots of the vehicle nodes according to the vehicle state information and carrying out a multi-time handshake protocol through the multi-channel transceiver module in a negotiation period so as to negotiate the use right of a service channel; the control module is also used for determining the frame length of each service channel according to the negotiation result of the negotiation period; therefore, the transmission reliability of the safety message is improved, the use fairness of the service channel is ensured, and meanwhile, the utilization rate of the channel is improved so as to meet the throughput requirement of the service message.
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.
It should be noted that in the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by one and the same item of hardware. The usage of the words first, second and third, etcetera do not indicate any ordering. These words may be interpreted as names.
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 changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations 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 include such modifications and variations.
In the description of the present invention, it is to be understood that the terms "first", "second" and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above should not be understood to necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (8)
1. A multi-channel MAC layer data self-adaptive transmission method in the Internet of vehicles is characterized by comprising the following steps:
dividing a channel into a control channel and a plurality of service channels based on a MAC layer protocol of multi-channel operation;
dividing the period of the control channel into a broadcasting period and a negotiation period;
in the broadcast period, each vehicle node which has access to the channel acquires vehicle state information sent by a neighboring vehicle node, and performs self-adaptive adjustment of the total number of MAC frame time slots according to the vehicle state information;
the negotiation period adopts a competitive access mechanism, so that the vehicle node negotiates the use right of the service channel through a multi-time handshake protocol;
determining the frame length of each service channel according to the negotiation result of the negotiation period;
the vehicle nodes in the Internet of vehicles transmit service information with high throughput demand according to the service channel with the determined frame length, and transmit delay-sensitive safety service information and control signaling messages according to the control channel;
the vehicle state information comprises vehicle identification information, occupied time slot information, available time slot values, total frame time slots, neighbor information and safety information;
and performing self-adaptive adjustment on the total number of the MAC frame time slots according to the vehicle state information, wherein the self-adaptive adjustment comprises the following steps:
judging whether the available time slot value per se is smaller than a preset minimum time slot threshold value or not according to vehicle state information sent by the neighbor vehicle node;
if so, increasing the frame time slot of the vehicle node;
if not, further judging whether the self available time slot value is larger than or equal to a preset maximum time slot threshold value;
and if so, recovering the frame time slot of the vehicle node, which is larger than the minimum time slot threshold value.
2. The method for adaptive transmission of multichannel MAC layer data in car networking according to claim 1, further comprising during the broadcast period:
a vehicle node to be accessed into a channel monitors the period of at least one control channel of the channel, acquires vehicle state information sent by a neighbor vehicle node, and acquires time slot occupation information in a two-hop communication range according to the vehicle state information sent by the neighbor vehicle node;
and the vehicle node to be accessed into the channel randomly selects an idle time slot to be accessed into the channel according to the time slot occupation information, and periodically sends the state information of the vehicle per se on the accessed time slot.
3. The method for the adaptive transmission of the multi-channel MAC layer data in the internet of vehicles according to claim 1, wherein when the frame time slot of the vehicle node is recovered, whether the vehicle node occupies the frame time slot to be recovered is also judged;
if yes, the vehicle node is switched to other available time slots in the period of the next control channel, and the frame time slot to be recovered is recovered after the switching is completed.
4. The method for the adaptive transmission of the multi-channel MAC layer data in the internet of vehicles according to claim 1, wherein the vehicle node negotiates the right of use of the service channel through a multi-handshake protocol, which includes:
and the vehicle node sends a service request to other vehicle nodes in the Internet of vehicles in the negotiation period according to the competitive access mechanism, so that the other vehicle nodes respond to the service request, generate a negotiation result according to the response result when receiving the response result, and broadcast the negotiation result.
5. The method for the adaptive transmission of the multi-channel MAC layer data in the internet of vehicles according to any one of claims 1 to 4, wherein each vehicle node is equipped with a half-duplex transceiver to alternately switch the operation between the control channel and the service channel.
6. The method for the adaptive transmission of the multi-channel MAC layer data in the Internet of vehicles according to any one of claims 1 to 4, wherein the control channel has a period of 100 ms.
7. A computer-readable storage medium, on which an implementation program of a multi-channel MAC data adaptive transmission method in an internet of vehicles is stored, which, when executed by a processor, implements the multi-channel MAC data adaptive transmission method in the internet of vehicles as recited in any one of claims 1 to 4.
8. The vehicle networking system is characterized by comprising a plurality of vehicle nodes, wherein data transmission is carried out between the vehicle nodes based on an adaptive multichannel MAC layer frame structure, and an implementation device of the multichannel MAC layer data transmission method comprises the following steps:
the system comprises a protocol stack module, a protocol selection module and a control module, wherein the protocol stack module is used for dividing a channel into a control channel and a plurality of service channels based on an MAC layer protocol of multi-channel operation, and dividing the period of the control channel into a broadcast period and a negotiation period, wherein the negotiation period adopts a competitive access mechanism;
the service processing module is used for processing different types of service messages and sending corresponding message sending or receiving requests to the control module;
the multi-channel transceiver module is used for the node to send or receive messages; transmitting vehicle state information in a control channel broadcast period and acquiring the vehicle state information transmitted by a neighbor vehicle node; sending or receiving a control signaling message in a control channel negotiation period; transmitting or receiving a service type message on a service channel;
the control module is used for adaptively adjusting the total number of the MAC frame time slots of the vehicle nodes according to the vehicle state information and carrying out a multi-time handshake protocol through the multi-channel transceiver module in a negotiation period so as to negotiate the use right of the service channel;
the control module is further configured to determine a frame length of each service channel according to a negotiation result of the negotiation period;
the vehicle state information comprises vehicle identification information, occupied time slot information, available time slot values, total frame time slots, neighbor information and safety information;
and performing self-adaptive adjustment on the total number of the MAC frame time slots according to the vehicle state information, wherein the self-adaptive adjustment comprises the following steps:
judging whether the available time slot value per se is smaller than a preset minimum time slot threshold value or not according to vehicle state information sent by the neighbor vehicle node;
if so, increasing the frame time slot of the vehicle node;
if not, further judging whether the self available time slot value is larger than or equal to a preset maximum time slot threshold value;
and if so, recovering the frame time slot of the vehicle node, which is larger than the minimum time slot threshold value.
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| CN112422373B (en) * | 2021-01-25 | 2021-08-24 | 北京理工大学 | Method for analyzing aggregated service time of domain control architecture of electric vehicle |
| CN113242530B (en) * | 2021-04-06 | 2022-05-24 | 华南理工大学 | Vehicle networking MAC layer data transmission method, device and medium based on time slot reservation |
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