KR102463141B1 - A reservation base resource allocation method and apparatus under aperiodic traffic in V2X communication - Google Patents

Abstract

Disclosed are a reservation-based resource allocation method and an apparatus for vehicle communication. In the case of aperiodic packet transmission, the reservation-based resource allocation method includes: (a) when a packet is generated, when a value of a resource re-allocation counter (RC) is “1”, frequency resources other than the currently used frequency allocating subchannels by determining whether to use them; (b) reserving time slots in order of highest probability according to a Markov model after analyzing the previous m packet transmission intervals; and (c) transmitting the packet using the allocated subchannel within the reserved time slot.

Description

A reservation base resource allocation method and apparatus under aperiodic traffic in V2X communication}

An object of the present invention is to provide a method and apparatus for allocating resources based on reservation of vehicle communication in an aperiodic packet transmission situation.

3GPP has been standardizing cellular V2X communication technology since Release 14. Currently, work has been completed up to Release 16 using 5G technology, and cellular V2X is called NR V2X. One of the core technologies of this NR V2X technology is sidelink communication that enables direct communication between vehicles. Resources for sidelink communication can be allocated in centralized (Mode 1) or distributed mode (Mode 2). In Mode 1, the base station is in charge of radio resource allocation, but in Mode 2, the vehicle autonomously allocates radio resources using a distributed algorithm called Sensing-Based Semi-Persistent Scheduling (SB-SPS). Since the base station is not everywhere, Mode 2 is the default mode.

However, this SB-SPS algorithm assumes that packet transmission occurs periodically. In the periodic transmission situation, as shown in FIG. 1 , a chain-type resource reservation is made, and a packet is transmitted according to the reserved resource. However, in reality, packet transmission is not performed periodically. 2 shows an interval at which packets are transmitted, assuming that packets are generated according to the ETSI CAM generation rule in an actual driving situation. When the SB-SPS is used in an aperiodic transmission situation, as shown in FIG. 3 , the reservation is broken, which may cause two problems.

First, a situation arises in which packets cannot be transmitted according to the reserved resource, which causes other vehicles to intensify resource competition in a high channel occupancy situation.

Second, a situation occurs in which a packet is sent to an unreserved resource. Since the resource is not reserved, other vehicles may use the resource, and in this case, a collision may occur for several seconds.

An object of the present invention is to provide a reservation-based resource allocation method and apparatus for vehicle communication in an aperiodic packet transmission situation in which resource reservation and allocation can be efficiently performed even in an aperiodic packet transmission situation in which a packet is transmitted only when generating a packet.

In addition, the present invention provides a method of vehicle communication in an aperiodic packet transmission situation that can solve a packet non-transmission and/or collision problem that occurs by using the SB-SPS algorithm in an aperiodic packet transmission situation through a probability-based resource reservation method. To provide a reservation-based resource allocation method and an apparatus therefor.

According to one aspect of the present invention, there is provided a reservation-based resource allocation method for vehicle communication in an aperiodic packet transmission situation.

According to an embodiment of the present invention, in the reservation-based resource allocation method in the aperiodic packet transmission situation, (a) when a packet is generated, the value of the resource re-allocation counter (RC: Reselection Counter) is "1" , allocating a subchannel by determining whether to use a frequency resource other than the currently used frequency; (b) reserving time slots in order of highest probability according to a Markov model after analyzing the previous m packet transmission intervals; and (c) transmitting the packet using the allocated subchannel within the reserved time slot.

이 되도록 트래픽 쉐이핑하는 단계를 더 포함하되, 상기 n은 1 이상의 자연수이며,

는 최소 패킷 전송 주기일 수 있다. Before step (b), the packet transmission interval of the packet is the same as the previously transmitted packet

Further comprising the step of shaping the traffic so that n is a natural number equal to or greater than 1,

may be the minimum packet transmission period.

을 만족하도록 타임 슬롯을 예약할 수 있다. In step (b), the packet transmission interval is

A time slot can be reserved to satisfy .

The step (a) is,

When the value of the resource reallocation counter is "0", the method may further include executing a sensing-based semi-persistent scheduling (SB-SPS) process to generate a list of candidate subchannels and then allocating any one. .

In step (b), if there is a previous reservation remaining after reserving the time slot, the previous reservation may be canceled.

According to another aspect of the present invention, an apparatus for executing a reservation-based resource allocation method of vehicle communication in an aperiodic packet transmission situation is provided.

According to an embodiment of the present invention, in an apparatus for allocating a reservation-based resource in an aperiodic packet transmission situation, the apparatus is a device for performing V2X communication, a memory for storing at least one command; and a processor for executing the instruction stored in the memory, wherein the instruction executed by the processor includes (a) when a packet is generated, a value of a resource reallocation counter (RC: Reselection Counter) is "1", allocating a subchannel by determining whether to use a frequency resource other than the currently used frequency; (b) reserving time slots in order of highest probability according to a Markov model after analyzing the previous m packet transmission intervals; and (c) transmitting the packet using the allocated subchannel within the reserved time slot.

By providing a reservation-based resource allocation method and apparatus for vehicle communication in aperiodic packet transmission situation according to an embodiment of the present invention, resource reservation and allocation efficiently even in aperiodic packet transmission situation in which packets are transmitted only during packet generation can make this possible.

In addition, the present invention also has an advantage in that it is possible to solve the problem of packet non-transmission and/or collision caused by using the SB-SPS algorithm in an aperiodic packet transmission situation through the probability-based resource reservation method.

In addition, the present invention has an advantage in that a packet reception rate and a communication range are extended as resource reservation and allocation are efficiently made even in aperiodic packet transmission situation.

1 is a diagram for explaining packet transmission in a conventional periodic transmission situation.
2 is a diagram illustrating an interval at which packets are transmitted when a packet is generated according to an ETSI CAM generation rule in an actual driving situation.
3 is a diagram for explaining a problem in the case of using the SB-SPS in an aperiodic transmission situation.
4 is a flowchart illustrating a reservation-based resource allocation method in an aperiodic situation according to an embodiment of the present invention.
5 is a flowchart illustrating a resource allocation method according to an embodiment of the present invention.
6 is a diagram illustrating a traffic shaping process according to an embodiment of the present invention;
7 is a flowchart illustrating a resource reservation process according to an embodiment of the present invention.
8 is a diagram illustrating a result of packet reception rate according to a reservation-based resource allocation method in an aperiodic communication situation according to an embodiment of the present invention;
9 is a view showing a result showing a communication range according to a reservation-based resource allocation method in an aperiodic communication situation according to an embodiment of the present invention.
10 is a block diagram schematically illustrating an internal configuration of an apparatus according to an embodiment of the present invention;
11 is a diagram illustrating a pseudo code for a resource allocation process according to an embodiment of the present invention.
12 is a diagram illustrating a pseudo code for a resource reservation process according to an embodiment of the present invention.

As used herein, the singular expression includes the plural expression unless the context clearly dictates otherwise. In this specification, terms such as “consisting of” or “comprising” should not be construed as necessarily including all of the various components or various steps described in the specification, some of which components or some steps are It should be construed that it may not include, or may further include additional components or steps. In addition, terms such as "...unit" and "module" described in the specification mean a unit that processes at least one function or operation, which may be implemented as hardware or software, or a combination of hardware and software. .

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

4 is a flowchart illustrating a reservation-based resource allocation method in an aperiodic situation according to an embodiment of the present invention, FIG. 5 is a flowchart illustrating a resource allocation method according to an embodiment of the present invention, and FIG. 6 is this It is a diagram illustrating a traffic shaping process according to an embodiment of the present invention, and FIG. 7 is a flowchart illustrating a resource reservation process according to an embodiment of the present invention. Hereinafter, a method of allocating resources in an aperiodic situation in V2X communication will be described.

In step 410, the device 400 generates a packet to be transmitted.

Unlike the related art, resource reservation and allocation may be performed in an aperiodic situation in which packet resources are reserved and allocated only at the point in time when packets are generated. Here, the resource may include frequency (sub-channel) and time (slot) coordinates. Hereinafter, it should be understood that resources include frequency and time coordinates, even if there is no separate description.

As described above, a method for reserving and allocating resources in an aperiodic situation, that is, when a packet is generated, will be described in detail.

In step 415 , the device 400 allocates a resource (eg, a subchannel) to be used for packet transmission.

A method of allocating resources will be described in more detail with reference to FIG. 5 .

In step 510 , when a packet is generated, the device 400 decrements a value of a resource reselection counter (RC) by a specified size (eg, 1).

In step 515, the device 400 determines whether the value of the resource reselection counter is 1.

If the value of the resource reselection counter is 1, in step 520 , the device 400 determines whether to use a frequency resource other than the currently used frequency. When the value of the resource reselection counter is 1, the currently used frequency resource (subchannel resource) may be used as it is, or a frequency resource other than the currently used frequency resource may be used.

If it is decided to keep the current frequency resource (ie, the subchannel resource) as it is, in step 525 the device 400 randomly allocates any one of 5 to 15 as the value of the resource reselection counter and then the current resource reselection counter can be summed with the value of

After summing the values of the resource reselection counter, the device 400 proceeds to the resource reservation process of step 425 of FIG. 4 . The resource reservation process will be described in more detail below with reference to related drawings.

However, if the resource of the currently used subchannel is not maintained as it is, that is, when it is determined to use another frequency resource, the resource reservation process in step 425 of FIG. 4 is performed.

If it is determined in step 515 that the value of the resource reselection counter is not 1, in step 535 the device 400 determines whether the value of the resource reselection counter is 0.

If the value of the resource reselection counter is not 0, the resource reservation process of step 425 of FIG. 4 is performed.

However, if the value of the resource reselection counter is 0, in step 535, the device 400 randomly selects one of the values of 5 to 15 as the value of the resource reselection counter, and executes the SPS algorithm to generate a list of candidate resources. After that, it randomly selects from the list of candidate resources and uses the selected resource. Since the process is the same as the pre-emption process of NR V2X, the overlapping description will be omitted.

The pseudo code for this resource allocation process is shown in FIG. 11 . When all of these resource allocation processes are completed, a resource reservation process is performed. This will be described below with reference to the related drawings.

When the resource allocation process as shown in FIG. 5 is completed, in step 420 , the device 400 performs a traffic shaping process. Here, the trapping shaping process is a process for giving periodicity to aperiodic traffic.

When a packet is generated in the facilities layer, which is an upper layer, the packet is delivered to the access layer. The device 400 does not directly transmit the packet transferred to the access layer, but may transmit the packet at the determined transmission time after determining the transmission time.

이 되도록 패킷 전송 주기를 결정한다. 여기서, n은 1이상의 자연수이며,

는 최소 패킷 전송 주기를 나타낸다.

는 CAM에 따른 패킷 전송 규칙에 따라 결정되며, 표준에 정의되어 있다. 예를 들어,

는 100ms일 수 있다. That is, when the device 400 transmits a packet to the access layer, the packet transmission interval with the previously transmitted packet is

The packet transmission period is determined so that where n is a natural number greater than or equal to 1,

denotes the minimum packet transmission period.

is determined according to the packet transmission rule according to the CAM and is defined in the standard. for example,

may be 100 ms.

It will be described in more detail with reference to FIG. 6 .

이 되도록 패킷 전송 주기를 결정할 수 있다. As shown in FIG. 6 , when a packet is generated in the facilities layer and delivered to the access layer, the packet transmission period with the previously transmitted packet is

It is possible to determine the packet transmission period to be this.

In step 425, the device 400 analyzes the previous m packet transmission periods and reserves resources (eg, time slots) in the order of highest probability according to the Markov model.

FIG. 7 is a flowchart of a resource reservation process, and a pseudo code for this is shown in FIG. 12 . A resource reservation process will be described in more detail with reference to FIGS. 7 and 12 .

In step 710 , the device 400 determines the next packet transmission period by analyzing the previous m packet transmission periods. In this case, the device 400 may determine a maximum of two in the order of the highest probability according to the Markov model. That is, the device 400 may reserve the corresponding resource by using the resource pointer by predicting the next CAM transmission interval by looking at the last M CAM transmission intervals.

이 되도록 결정할 수 있다. In this way, in determining the next packet transmission period, the device 400 analyzes the previous m packet transmission periods and determines in the order of highest probability according to the Markov model, the next packet transmission period is the previous trapping shaping process (that is, , the packet transmission period with the previously transmitted packet determined in step 420)

It can be decided to be

이 되는 슬롯으로 결정할 수 있다. That is, in determining the next packet transmission period by analyzing the previous m packet transmission periods, the device 400 determines the packet transmission period with the previously transmitted packet.

It can be determined by the slot that becomes

In step 715 , the device 400 adds a bit for canceling the reservation when there are remaining reserved resources.

In step 720, the device 400 determines whether the value of the resource reselection counter is 1.

If the value of the resource reselection counter is not 1, in step 725, the device 400 selects and reserves a resource separated by the determined packet transmission period.

In step 730, the device 400 transmits a packet along with information on the reserved resource.

As a result of determination in step 720, if the value of the resource reselection counter is 1, in step 735, the device 400 executes the SPS process to determine a list of candidate resources, selects any one among them, and determines the starting point of execution of the next packet. After that, the process proceeds to step 730. An execution start point of the next packet may be determined in consideration of the determined packet transmission period.

8 is a result showing a packet reception rate according to a reservation-based resource allocation method in an aperiodic communication situation according to an embodiment of the present invention, and FIG. It is a result showing the communication range according to the resource allocation method.

As shown in FIG. 8 , it can be expected that resource reservation and allocation are efficiently made even in the aperiodic packet transmission situation, thereby increasing the packet reception rate (PRR). In addition, as shown in FIG. 9 , it can be seen that a communication range of up to 70 m or more is extended.

10 is a block diagram schematically illustrating an internal configuration of an apparatus according to an embodiment of the present invention. Here, the device 400 is a subject that performs V2X communication, and may be a vehicle or a terminal mounted on the vehicle.

Referring to FIG. 10 , an apparatus 400 according to an embodiment of the present invention includes a communication unit 1010 , a memory 1020 , and a processor 1030 .

The communication unit 1010 is a means for transmitting and receiving data with other devices through a communication network.

The memory 1020 stores at least one instruction.

The processor 1030 is a means for controlling internal components (eg, the communication unit 1010 , the memory 1020 , etc.) of the apparatus 400 according to an embodiment of the present invention.

Also, the processor 1030 may execute instructions stored in the memory 1020 . The instruction executed by the processor 1030 may perform respective steps as described with reference to FIGS. 4 to 9 .

Up to now, the present invention has been looked at focusing on the embodiments thereof. Those of ordinary skill in the art to which the present invention pertains will understand that the present invention may be implemented in a modified form without departing from the essential characteristics of the present invention. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the present invention is indicated in the claims rather than the foregoing description, and all differences within the scope equivalent thereto should be construed as being included in the present invention.

400: device
1010: communication department
1020: memory
1030: Processor

Claims (7)

In a reservation-based resource allocation method in an aperiodic packet transmission situation of a device performing V2X communication,
(a) allocating a subchannel by determining whether to use a frequency resource other than the currently used frequency when a value of a resource reselection counter (RC) is "1" when a packet is generated;
(b) reserving time slots in order of highest probability according to a Markov model after analyzing the previous m packet transmission intervals; and
(c) transmitting the packet based on the subchannel allocated within the reserved time slot.
The method of claim 1,
Before step (b),
The packet transmission interval of the packet is the same as the previously transmitted packet.

Further comprising the step of shaping the traffic so that
Wherein n is a natural number of 1 or more,

A reservation-based resource allocation method in an aperiodic packet transmission situation, characterized in that is the minimum packet transmission period.
3. The method of claim 2,
Step (b) is,
The packet transmission interval is

A reservation-based resource allocation method in an aperiodic packet transmission situation, characterized in that the resource is reserved to satisfy
The method of claim 1,
The step (a) is,
When the value of the resource reallocation counter is "0", the method further comprises the step of generating a list of candidate subchannels by executing a sensing-based semi-persistent scheduling (SB-SPS) process and then allocating any one A reservation-based resource allocation method in an aperiodic packet transmission situation.
The method of claim 1,
Step (b) is,
Reservation-based resource allocation method in an aperiodic packet transmission situation, characterized in that if there is a previous reservation remaining after reserving the time slot, the previous reservation is canceled.
A computer-readable non-transitory recording medium storing program code for performing the method according to any one of claims 1 to 5.
In the device for allocating a reservation-based resource in an aperiodic packet transmission situation, the device is a device for performing V2X communication,
a memory storing at least one instruction; and
A processor for executing instructions stored in the memory,
The instructions executed by the processor are
(a) allocating a subchannel by determining whether to use a frequency resource other than the currently used frequency when a value of a resource reselection counter (RC) is "1" when a packet is generated;
(b) reserving time slots in order of highest probability according to a Markov model after analyzing the previous m packet transmission intervals; and
(c) transmitting the packet using the allocated subchannel within the reserved time slot.

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