CN107005880B - Communication method, server, roadside unit and node - Google Patents

Abstract

The application provides a communication method, an RRM server, an RSU and a node. The method includes: the radio resource management RRM server segments the area in the communication network to form at least one segment for at least one RSU; the RRM server allocates a channel for the at least one segment; the RRM server sends the at least Each RSU in an RSU sends network segment information and channel allocation information, wherein the network segment information indicates the segment of the RSU, and the channel allocation information indicates the channel allocated for the segment, so that the RSU can pass the channel allocated for the segment Channels communicate with nodes entering the segment.

Description

Communication method, server, roadside unit and node

technical field

The present invention generally relates to the technical field of communication, and more specifically, relates to a communication method, a server, a roadside unit and a node.

Background technique

Vehicular Ad hoc Networks (VANET) enable communication between nearby vehicles and between vehicles and nearby fixed infrastructure. This leads to the design of multiple applications to improve the safety of future transportation systems and to provide many industrial services and entertainment services. Dedicated Short Range Communication (DSRC, Dedicated Short Range Communication), as the main communication technology, enables vehicle-to-vehicle (V2V, vehicle-to-vehicle) and vehicle-to-infrastructure (V2I, vehicle-to-infrastructure) communication to realize such applications. Due to the large number of vehicles and the complex road architecture, in terms of large networks and a large number of nodes, it is expected to form large dense vehicle networks in highways and urban VANETs.

The medium access control (MAC, Medium Access Control) sublayer of the widely used DSRC system relies on random access channels such as carrier sensing medium access/collision avoidance (CSMA/CA, Carrier Sensing Medium Access/CollisionAvoidance) Sharing technology, and use Enhanced Distributed Channel Access (EDCA) business differentiation and multi-channel function to expand. For example, the network access in the vehicle environment (WAVE, Vehicular Environment) and the European Telecommunications Standards Institute (ETSI, European Telecommunications Standards Institute) intelligent transportation system (ITS, Intelligent Transport Systems) G5 standard use electrical and Institute of Electronics Engineers (IEEE) 802.11p MAC sublayer.

There are 6 traffic channels (SCH) and 1 control channel (CCH) in the existing standard, and the channel access time is divided into synchronization intervals. Each interval consists of a guard interval and alternating fixed-length intervals called CCH intervals and SCH intervals. In the standard, the duration of the CCH interval and the SCH interval is defined as 50 milliseconds (ms). During the CCH interval, all nodes monitor the CCH to exchange safety messages and other control packets. During the SCH interval, a node sends potentially non-secure application data on the SCH.

However, in the above-mentioned existing standards, it is impossible to effectively utilize radio resources adapted to such network conditions: in congested urban areas with dense VANETs, a large number of safety messages and control messages need to be transmitted within the CCH interval. The fixed length of CCH may not provide enough bandwidth in these scenarios, leading to potential collisions and QoS degradation. On the other hand, if the node density is sparse, the CCH interval will be idle for a long time.

Contents of the invention

Embodiments of the present invention provide a communication method, a server, a roadside unit, and a node that can improve the utilization rate of wireless resources.

In a first aspect, the present application provides a communication method. The RRM server receives network state information sent by at least one RSU. The network state information sent by each RSU of the at least one RSU indicates a density of nodes covered by the RSU. The RRM server segments the areas in the communication network according to the network state information, so as to form at least one segment respectively for the at least one RSU. The RRM server allocates a channel for the at least one segment. The RRM server sends network segmentation information and channel allocation information to each RSU of the at least one RSU. The network segment information indicates the segment of the RSU, and the channel allocation information indicates the channel allocated for the segment, so that the RSU communicates with the node entering the segment through the channel allocated for the segment to communicate.

According to an embodiment of the present invention, the RRM server performs network segmentation and channel allocation for segments according to the network status information reported by the RSU, and notifies the RSU of the network segmentation information and channel allocation information , so that the RSU communicates with the node entering the segment through the channel allocated for the segment, thereby reducing the probability of collision and quality degradation, thereby improving the utilization rate of wireless resources.

According to a first implementation manner of the method in the first aspect, the node density includes the number of nodes within different distances from the RSU. In this case, before the RRM server segments the area in the communication network, the RRM server also determines that the area is congested according to the number of nodes within different distances from the RSU. Therefore, instead of using a fixed-length CCH, segmentation and channel allocation are performed based on whether the area is congested, so as to reduce the collision probability according to different network conditions and realize dynamic channel allocation.

According to the second implementation manner of the method described in the first implementation manner, the method further includes: the RRM server determines that the area becomes less congested, and sends a packet to each RSU of the at least one RSU segment revocation information. The segment revocation information indicates to revoke the segment and channel allocation so that the RSU communicates with nodes entering the coverage of the RSU through legacy channels. The solution of the present application can be compatible with traditional channel allocation solutions since the segments can be withdrawn when the area becomes less congested.

According to a third implementation of the method of the first aspect or any of the preceding implementations of the first aspect, the RRM server divides the area into a plurality of squares, each square has an RSU in the center, and the sides of the square of RSU(a) The length L _S is:

L _S =min(D _max ,L), where:

D _max ＝max({D _i |N _i ≤N _desired (a)})

where (x _a , y _a ) is the longitude and latitude of RSU(a), N _i is the number of nodes in different ranges of RSU(a), N _desired (a) is the desired node of said square of RSU(a) density. Due to the presence of L and _Dmax described above, adjacent segments can use non-overlapping channels to avoid interference from nodes in adjacent segments.

In a second aspect, the present application provides a method for transmitting data. The RSU sends network status information to the RRM server. The network state information indicates the density of nodes covered by the RSU. The RSU receives network segmentation information and channel allocation information sent by the server. The network segment information indicates a segment of the RSU, the channel allocation information indicates a channel allocated for the segment, and the segment is formed by segmenting an area in the communication network by the RRM server are respectively directed to one of the at least one segment of the at least one RSU. The RSU sends the network segmentation information and the channel allocation information to the nodes covered by the RSU. The RSU communicates with nodes in the segment over the channel allocated for the segment.

According to an embodiment of the present invention, the RRM server performs network segmentation and channel allocation for segments according to the network status information reported by the RSU, and notifies the RSU of the network segmentation information and channel allocation information , so that the RSU can communicate with the node entering the segment through the channel allocated for the segment, thereby reducing the collision probability and quality degradation, and improving the utilization rate of wireless resources.

According to the first implementation manner of the method described in the second aspect, the method further includes: the RSU acquiring network status information according to the report of the node covered by the RSU.

According to a second implementation of the method according to the second aspect or any preceding implementation of the second aspect, the density of nodes includes the number of nodes within different distances from the RSU, and the method further includes: the RSU according to the The number of nodes within different distances from the RSU determines the coverage congestion of the RSU.

According to a third implementation of the method according to the first aspect or any of the foregoing implementations of the second aspect, the method further includes: the RSU receives segment revocation information from the RRM server, and The RSU's covered nodes communicate. The segment revocation information indicates revocation of the segment and channel allocation.

According to a fourth implementation of the method in any of the foregoing implementations of the first aspect or the second aspect, the RSU reports the network status information to the NCC periodically, or reports the network status information to the NCC when at least one of the predetermined conditions is met. status information.

In a third aspect, the present application provides a method for transmitting data. The node receives the network segment information and channel allocation information from the roadside unit RSU, determines that the node is in the segment according to the network segment information, and communicates the channel allocated for the segment with the RSUs communicate. The network segment information indicates a segment of the RSU, the channel allocation information indicates a channel allocated for the segment, and the segment is formed by segmenting an area in the communication network by the RRM server are respectively directed to one of the at least one segment of the at least one RSU.

According to a first implementation manner of the method described in the third aspect, the method further includes: the node receiving segment revocation information from the RSU, and communicating with the RSU through a legacy channel. The segment revocation information indicates revocation of the segment and channel allocation.

In a fourth aspect, the present application provides a server. The server comprises means for performing the method of the first aspect.

In a fifth aspect, the present application provides an RSU. The RSU comprises means for performing the method of the second aspect.

In a sixth aspect, the present application provides a node. The node comprises means for performing the method of the third aspect.

In some embodiments, a node is a vehicle including an OBU.

In some embodiments, the allocating channels for the at least one segment includes: allocating channels for the at least one segment from one PCCH, two LCCHs and four LSCHs, and assigning channels to the other segments adjacent to the segment One segment allocates the PCCH, another LCCH and two other LSCHs. The PCCH can be shared between adjacent segments in order to be compatible with legacy solutions. Within each segment, a node is allowed to use one LCCH and two LSCHs. Adjacent segments may use non-overlapping channels to avoid interference from nodes in adjacent segments. Since each segment is assigned an LCCH for sending control messages, the collision probability and QoS degradation are reduced, thereby improving the utilization of radio resources. Furthermore, if both LCCHs for the segment are occupied, the LCCH can be used for data transmission in order to support more nodes in the segment.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present invention more clearly, the drawings required in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to these drawings without creative efforts.

FIG. 1 depicts an architecture diagram of a communication system according to an embodiment of the present invention.

FIG. 2 depicts a schematic diagram of functional entities of a communication system 100 according to an embodiment of the present invention.

Fig. 3 depicts a schematic flowchart of a communication method according to an embodiment of the present invention.

Fig. 4 depicts a schematic flowchart of a communication method according to another embodiment of the present invention.

Fig. 5 depicts a schematic flowchart of a communication method according to another embodiment of the present invention.

Fig. 6 depicts a schematic flowchart of a communication process according to another embodiment of the present invention.

Figure 7 depicts the format of packets sent from the RSU to the RRM server according to one embodiment of the invention.

Figure 8 depicts the format of a packet sent from an RRM server to an RSU according to an embodiment of the invention.

Figure 9 depicts the format of a packet sent from an RSU to a node according to an embodiment of the invention.

Figure 10 depicts an example table of the number of nodes at different distances from an RSU according to an embodiment of the invention.

Fig. 11 depicts a schematic flowchart of a communication process according to another embodiment of the present invention.

Figure 12 depicts the format of another packet sent from the RRM server to the RSU according to an embodiment of the present invention.

Fig. 13 depicts a schematic flow diagram of segmentation of a network according to an embodiment of the invention.

Fig. 14 is a schematic network model according to an embodiment of the present invention.

Figure 15 is a simplified block diagram of a server according to an embodiment of the present invention.

Figure 16 is a simplified block diagram of an RSU according to an embodiment of the invention.

Figure 17 is a simplified block diagram of a node according to another embodiment of the invention.

18 is a simplified block diagram of a computing device.

Detailed ways

The technical solutions of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, these embodiments are only some exemplary embodiments of the present invention, and the present invention is not limited to these embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention also belong to the protection scope of the present invention.

The technology involved in the embodiment of the present invention may be called Dynamic Network Segmentation-based Multi-channel MAC Protocol (DNSM-MAC).

FIG. 1 depicts an architecture diagram of a communication system 100 according to an embodiment of the present invention.

The communication system 100 may be a VANET including a network control center (NCC) 110 , a plurality of roadside units (RSUs) 120 and a plurality of nodes (eg, vehicles) 130 . It should be understood that the nomenclature of these network nodes in communication system 100 is for identification only and should not be construed as limiting.

The NCC 110 includes an RRM server 111 that plays a key role in the implementation of the embodiment of the present invention and further implements other functions. However, for ease of description, only the RRM server 111 is described in detail. The RRM server 111 is used to segment the areas in the network and allocate channels to the segments.

RSU 120 is connected to NCC 110 via a wired or wireless link such as Long Term Evolution (LTE) or Internet 140 . The RSUs 120 are usually located on the side of the road at a distance from each other. The distance between two RSUs 120 may be equal to the effective communication range of the underlying DSRC technology (eg, 500m for IEEE 802.11p). The RSU 120 is used to collect network status information from the nodes 130 within its coverage area, and to forward packets between the nodes 130 and the NCC 110 .

FIG. 2 depicts a schematic diagram of functional entities of a communication system 100 according to an embodiment of the present invention.

Referring to FIG. 2 , the functional blocks of these entities are shown in FIG. 2 , including NCC 110 , RSU 120 and OBU 131 in node 130 . The RRM server 111 is located in the NCC 110 and assumes the function of channel allocation. The network segmentation function is distributed between RSU 120 and RRM server 111 . Each node 130 is equipped with a DSRC network interface for communication with each other and with the RSUs. The DSRC interface may include DNSM-MAC layer, 802.11p PHY layer and other layers. The RRM server and the RSU can communicate with each other through the Internet interface.

Embodiments of the present invention provide an efficient dynamic technique for allocating channels in a multi-channel VANET, wherein, with the assistance of RSU and RRM servers, available channels are dynamically allocated to Different segments of a dynamically defined network near the RSU.

Fig. 3 depicts a schematic flowchart of a communication method according to an embodiment of the present invention. The method in FIG. 3 is implemented by the RRM in FIG. 1 .

310. The RRM server receives network state information sent by at least one RSU, where the network state information sent by each RSU of the at least one RSU indicates the density of nodes covered by the RSU.

320. The RRM server segments the areas in the communication network according to the network state information, so as to form at least one segment respectively for the at least one RSU.

For example, the area may refer to a highway or a section of an urban area. After segmentation, each RSU can only correspond to one segment, and each RSU can be located at the center of the segment. The segment sizes of different RSUs can be different or the same.

330. The RRM server allocates a channel for the at least one segment.

For example, the RRM server may allocate multiple channels to each segment, for example, the channels allocated to each segment may include a common CCH, a local CCH and two local SCHs. Adjacent segments can share a common CCH, or have different local CCHs and local SCHs.

340. The RRM server sends network segment information and channel allocation information to each RSU of the at least one RSU, where the network segment information indicates a segment of the RSU, and the channel allocation information indicates a channel allocated for the segment , so that the RSU communicates with the nodes entering the segment through the channel allocated for the segment.

According to the embodiment of the present invention, the RRM server performs network segmentation and channel allocation for the segments according to the network status information reported by the RSU, and notifies the RSU of the network segment information and channel allocation information, so that the RSU The channel assigned by the segment communicates with the nodes entering the segment, thereby reducing the probability of collision and quality degradation, and improving the utilization of wireless resources.

Specifically, when a node equipped with an on-board unit (OBU) is within the communication range or coverage of the RSU, the node communicates with the RSU. The RSU can determine the network state information according to the information reported by the nodes covered by the RSU, and send the network state information to the RRM server. For example, in normal state, during CCH intervals, RSU and nodes monitor the CCH for exchanging safety messages and other control packets, while during SCH intervals, RSUs and nodes send potentially non-safety application data on SCH. However, when the RRM server detects a congested area according to the network state information, the RRM server may perform network segmentation according to the network state information to provide a plurality of segments respectively centered on RSUs, and allocate channels for each segment. The RRM server sends network segment segment information indicating the segment of the RSU and channel allocation information indicating channel allocation for the RSU, and the RSU broadcasts the network segment information and channel allocation information to the nodes, and then the nodes pass The channel assigned by the segment communicates with the RSU.

Optionally, as another embodiment, the node density includes the number of nodes within different distances from the RSU, and before 320, the method further includes: the RRM server determines that the area is congested according to the number of nodes within different distances from the RSU .

For example, if the number of nodes within 50m from the RSU exceeds 10, or the number of nodes within 100m from the RSU exceeds 20, the coverage area of the RSU is regarded as a congested area. Additionally, multiple thresholds can be set to determine congested areas. The purpose of introducing multiple thresholds is to make some areas with super popular traffic flow have more nodes than others. For example, the node density of urban centers is much higher than that of subordinate rural areas. In order to avoid that some areas with very popular traffic flow are divided into ultra-small segments that cannot be supported by enough RSUs, which will lead to many problems such as channel allocation, interference between adjacent segments, and unaware of CAM from adjacent vehicles, etc., the coverage Different thresholds can be set. Therefore, instead of using a fixed-length CCH, segmentation and channel allocation are performed based on whether the area is congested, so as to reduce the collision probability according to different network conditions and realize dynamic channel allocation.

Optionally, as another embodiment, the method in FIG. 3 further includes: the RRM server determines that the area becomes uncongested, and sends segment revocation information to each RSU in the at least one RSU, wherein the segment revocation The information indicates that the segment and channel allocation are revoked so that the RSU communicates with nodes entering the RSU's coverage through the legacy channel. The solution of the present application can be compatible with traditional channel allocation solutions since the segmentation can be withdrawn when the area becomes less congested.

For example, if the number of nodes within 50m from the RSU is less than 10, or the number of nodes within 100m from the RSU is less than 20, the coverage area of the RSU is considered as an uncongested area. In this case, no segmentation is necessary, so the segmentation is undone. The RSU and vehicle are then switched to legacy channels for listening to control messages and data, thus providing a flexible channel allocation scheme.

At 320, the RRM server divides the area into a plurality of squares, each square has an RSU in the center, and the side length L of the square of the RSU (a) is:

L _S =min(D _max ,L), where:

D _max ＝max({D _i |N _i ≤N _desired (a)})

where (x _a , y _a ) is the longitude and latitude of RSU(a), N _i is the number of nodes in different ranges of RSU(a), N _desired (a) is the desired node density of the square of RSU(a). Here N, a, b, c and i are all positive integers.

Due to the above L and D _max , adjacent segments can use non-overlapping channels to avoid interference from nodes in adjacent segments.

In 330, the RRM server allocates channels for the at least one segment from a common control channel PCCH, two local control channels LCCH and four local traffic channels LSCH, wherein the segment is allocated the PCCH, one LCCH and two LSCH, and assign the PCCH, another LCCH, and two other LSCHs to another segment adjacent to this segment.

In a conventional channel allocation scheme, 7 channels (1 CCH and 6 SCHs) are allocated to RSUs in the communication network. That is, two adjacent RSUs must share one CCH, and in such a scenario, sufficient bandwidth may not be provided, resulting in a potential high collision rate and QoS deterioration. However, in the embodiment of the present invention, two LCCHs can be assigned to two adjacent RSUs, thereby further reducing collision probability and QoS deterioration, and realizing dynamic channel allocation.

Fig. 4 depicts a schematic flowchart of a communication method according to another embodiment of the present invention. The method in Fig. 4 is realized by the RSU in Fig. 1 .

410. The roadside unit (RSU) sends network state information to the radio resource management RRM server, where the network state information indicates the density of nodes covered by the RSU.

420. The RSU receives network segment information and channel allocation information sent by the RRM server, where the network segment information indicates the segment of the RSU, the channel allocation information indicates the channel allocated for the segment, and the segment is the One of the at least one segment respectively for the at least one RSU formed by segmenting the area in the communication network by the RRM server.

430. The RSU sends network segmentation information and channel allocation information to the nodes covered by the RSU. For example, the RSU may broadcast the segmentation information and the channel assignment information to nodes.

440. The RSU communicates with the nodes in the segment through the channel allocated for the segment.

According to an embodiment of the present invention, the RRM server performs network segmentation and channel allocation for the segments according to the network state information reported by the RSU, and notifies the RSU of the network segmentation information and channel allocation information, so that the RSU can pass The channel allocated for the segment communicates with the nodes entering the segment, thereby reducing the probability of collision and quality degradation, thereby improving the utilization of wireless resources.

Optionally, as another embodiment, the method in FIG. 4 further includes: the RSU acquires network state information.

Optionally, as another embodiment, the density of nodes includes the number of nodes within different distances from the RSU, and before step 430, the method in FIG. 4 further includes: determining the number of nodes of the RSU according to the number of nodes within different distances from the RSU Coverage congestion.

Optionally, as another embodiment, the method in FIG. 4 further includes: the RSU receives segment revocation information from the RRM server, and communicates with a node that enters the coverage of the RSU by switching to a legacy channel, wherein the segment revocation The information indicates that the segment and channel allocation are revoked.

In 430, the RSU periodically reports network status information to the NCC.

Optionally, as another embodiment, in 430, when at least one of the predetermined conditions is met, the RSU reports the network status information to the NCC.

According to an embodiment of the present invention, a common control channel PCCH, two local control channels LCCH and four local traffic channels are allocated for the at least one segment, a PCCH, an LCCH and two LSCHs are allocated for the segment, and for Another segment adjacent to this segment allocates the PCCH, another LCCH and two other LSCHs.

Fig. 5 depicts a schematic flowchart of a communication method according to another embodiment of the present invention. The method in FIG. 5 is implemented by the nodes in FIG. 1 .

510. The node receives network segment information and channel allocation information from the roadside unit RSU, wherein the network segment information indicates the segment of the RSU, the channel allocation information indicates the channel allocated for the segment, and the segment is One of the at least one segment respectively for the at least one RSU formed by segmenting the area in the communication network by the RRM server.

520. The node determines that the node is in the segment according to the network segment information.

530. The node communicates with the RSU through the channel allocated for the segment.

According to an embodiment of the present invention, the RRM server performs network segmentation and channel allocation to the segments according to the network status information reported by the RSU, and notifies the RSU of the network segmentation information and channel allocation information, so that the RSU can pass The channel allocated by the segment communicates with the nodes entering the segment, thereby reducing the probability of collision and quality deterioration, thereby improving the utilization rate of wireless resources.

Optionally, as another embodiment, the method in FIG. 5 further includes: the node receives segment revocation information from the RRM server, and communicates with the RSU through a legacy channel, wherein the segment revocation information indicates that the segment is revoked and channel allocation.

According to an embodiment of the present invention, a common control channel PCCH, two local control channels LCCH and four local traffic channels are allocated for the at least one segment, a PCCH, an LCCH and two LSCHs are allocated for the segment, and for Another segment adjacent to this segment allocates the PCCH, another LCCH and two other LSCHs.

According to an embodiment of the invention, the node is a vehicle comprising an on-board unit OBU.

Fig. 6 depicts a schematic flowchart of a communication process according to another embodiment of the present invention.

610. The RSU collects node IDs and location information from nodes within the coverage of the RSU by grouping.

For example, once a new node (e.g., a vehicle) enters the coverage (or communication range) of the RSU, each time a packet (e.g., ACK, RTS, CTS, DATA) is sent, the RSU obtains the node ID of the node and lists it in the table Create an entry for this node in . Then when the node broadcasts a Cooperative Awareness Message (CAM, Cooperative Awareness Message) or a decentralized environment notification message (DENM, Decentralized Environmental Notification Message), or sends a packet through multicast/unicast, the RSU collects position information and motion information, and Update the node's entry in the table. This can be achieved, for example, by Local Dynamic Mapping (LDM) in the ITS architecture ETSI TR 102 863 (V1.1.1).

615. The RSU determines the network status information according to the collected location information of the nodes.

For example, the RSU can determine the number of nodes within the communication range and the number of nodes at different distances from the RSU according to the location information of the nodes.

Figure 10 depicts a table indicating the number of nodes at different distances from an RSU, according to an embodiment of the invention. Referring to Figure 10, within the range 0-100m corresponding to range index 1, the number of adjacent nodes of RSU is 50, within the range 0-200m corresponding to range index 2, the number of adjacent nodes of RSU is 80, and in Within the range 0-500m corresponding to the range index 3, the number of adjacent vehicles of the RSU is 200, and so on.

620. The RSU sends a report to the RRM server in the NCC.

The RSU can send a report to the RRM server in the NCC to help find suitable coverage for the network segment. This report includes network status information.

Figure 7 depicts the format of packets sent from the RSU to the RRM server according to one embodiment of the invention. Referring to FIG. 7 , the sender ID field 710 indicates the ID of the RSU, and the length of the field 710 may be 32 bits. The destination ID field 720 indicates the ID of the RRM, and the length of the field 720 may be 32 bits. Since the embodiment of the present invention is implemented in the MAC sublayer, the MAC address can be used as the ID of the network node. The packet type field 730 indicates the type of the packet, for example, the packet type indicates that the packet is an RSU report packet, and the length of the field 730 may be 4 bits. The length field 740 indicates the size of the packet, and the length of the field 740 may be 16 bits. The range number (Range No.) field 750 indicates the range index 1 of the RSU, and the length of the field 750 may be 8 bits. The vehicle number field (No. of Veh.) 760 indicates the total number of active vehicles within the distance D1 corresponding to the range index 1, and the length of the field 760 may be 16 bits. The range number field 770 indicates the range index n of the RSU, and the length of the field 770 may be 8 bits. The vehicle number field 780 indicates the total number of active vehicles within the distance Dn corresponding to the range index 1, and the length of the field 780 may be 16 bits. For simplicity, similar range index fields 2 to n-1 and corresponding vehicle number fields D ₂ to D _n-1 are omitted in FIG. 7 , where n represents the number of coverage areas of the RSU, and n is a positive integer.

In addition, the RSU can send reports to the NCC periodically or only when certain trigger conditions (for sending network status information updates) are met. An example in the latter case is to define a set of predefined thresholds for the level of network congestion that can be configured for individual RSUs. The RSU can alert the RRM server only when the number of vehicles within the corresponding range of the RSU is greater than a predefined threshold.

It should be understood that each RSU in the communication network can collect location information and movement information from vehicles within the coverage of the RSU, and send a report carrying network status information to the RRM server.

630. The RRM server detects a congested area of the network.

The RRM server can identify whether there is congestion in the area according to the number of active nodes (node density) within the communication range of the RSU in the area. If the node density in a certain area is greater than the threshold N _desired (can be adjusted or preset), it is identified as congestion.

Optionally, as another embodiment, congestion may be identified for different ranges of each RSU. For example, thresholds for different communication ranges can be predefined in the RRM server.

640. If the RRM server determines that there is a congested area in the communication network, the RRM server performs network segmentation.

The RRM can divide the congested area into multiple segments, for example, into multiple squares, each square centered on the RSU. Embodiments of the present invention are not limited thereto, for example, the segments may have other shapes, such as circles, hexagons, and the like.

The following takes a square segment as an example to describe a congested network segment.

First, the RRM server calculates the side length L _s of the square (section) centered on the RSU. The side length of the square may also be adapted to at least one of the presence of adjacent RSUs, latency constraints of the ITS use case, and node density.

In the following, network segmentation is described by taking a network with adjacent RSUs and node density as an example.

a) Consider the presence of adjacent RSUs:

If multiple RSUs are available in a congested area, the RRM server divides the area into multiple squares, each square is centered on the RSU, and the side length L is given by the following formula:

Where (x _a , y _a ) is the longitude and latitude of RSU(a), a, b and c can be integers.

b) Consider the desired node density:

The RRM server takes into account the reported node density around each RSU to calculate edge lengths. The RRM server obtains the maximum distance D _max when the node density in a certain area meets the required node density by the following formula:

D _max ＝max({D _i |N _i ≤N _desired (a)})

Where N _i is the number of nodes in a certain area (distance from RSU(a) 0 to D _i m), i can be an integer, and N _desired (a) is the desired node density of a square for RSU(a).

c) Finally, the RRM server chooses the minimum value between D _max and L as the final result of the side length L _S of each segment.

L _S =min(D _max ,L)

It should be understood that the above-mentioned methods for performing segmentation are merely examples. Embodiments of the present invention are not limited thereto, and other segmentation methods (for example, evenly dividing congested areas) may also be used.

650. The RRM server allocates channels for the network segment.

After the network is segmented, the RRM server can allocate channels for the network segment. In order to be compatible with existing standards (eg, IEEE1609.4), 7 channels are still used. One of the seven channels is designated as a common control channel (PCCH) shared between adjacent segments. Of the remaining six channels, two are called local control channels (LCCH), and the remaining four are used as local traffic channels (LSCH). In this embodiment, the vehicle initially operates with a multi-channel MAC. If a new vehicle (entering the network after segmentation) misses the message, the RSU occupies the Common Control Channel (PCCH) in the segmented network to broadcast the segmented information. Within each segment, a node is allowed to use one LCCH and two LSCHs. Adjacent segments can use non-overlapping channels to avoid interference from nodes in adjacent segments. For example, in the example scene shown in FIG. 13 , it is assumed that an area in road 1310 can be divided into segments 1311 , 1312 and 1313 , and another area in road 1320 can be divided into segments 1321 , 1322 and 1323 . Furthermore, segment 1321 may be assigned LCCH 1 , LSCH 1 , and LSCH 2 , and segment 1322 may be assigned LCCH 2 , LSCH 3 , and LSCH 4 . The nodes in segment 1323 can then reuse the same channel as segment 1321 without causing any interference to the nodes in segment 1323 because the nodes in segment 1323 are far enough apart.

The LCCH is used as the segment local CCH over which emergency messages, channel negotiation and segment cancellation are sent, while the LSCH is used as the segment local SCH for data transmission. Since only two traffic channels in each segment can be used for data transmission, there may be no channels for multiple pairs of nodes. Therefore, if both traffic channels of the segment are occupied at this time, the LCCH may be allowed for data transmission after successful channel negotiation. The channel access mechanism in each segment is similar to the Asynchronous Multi-Channel MAC (AMCMAC, Asynchronous MultiChannel MAC) scheme.

660. The RRM server sends network segmentation information and channel allocation information to the RSU.

After network segmentation and channel allocation, the RRM server sends a packet carrying network segmentation information and channel allocation information to each RSU. The network segment information includes a side length of the segment for the RSU, and the channel allocation information includes a list of channels allocated for the segment.

Figure 8 depicts the format of a packet sent from an RRM server to an RSU according to an embodiment of the invention. Referring to FIG. 8 , the sender ID field 810 indicates the ID of the RRM server, and the length of the field 810 may be 32 bits. The destination ID field 820 indicates the ID of the RSU, and the length of the field 820 may be 32 bits. Since the embodiments of the present invention are implemented in the MAC sublayer, the MAC address can be used as the ID of the network node. The packet type field 830 indicates the type of the packet, and the length of the field 830 may be 4 bits. The LS field 840 indicates the side length of the segment for the RSU, and the length of the field 840 may be 12 bits. The channel field 850 represents a list of channels allocated for the segment, and the length of the field 850 may be (8 bits)*the total number of channels allocated for the segment.

670. The RSU notifies the node of network segmentation information and channel allocation information.

After receiving the network segmentation information and channel allocation information from the NCC, the RSU will broadcast the network segmentation information and channel allocation information to the vehicles within its coverage through the PCCH. The network segment information and channel allocation information can be carried in packets.

Figure 9 depicts the format of a packet sent from an RSU to a node according to an embodiment of the invention.

Referring to FIG. 9 , the sender ID field 910 indicates the ID of the RSU, and the length of the field 910 may be 32 bits. The destination ID field 920 includes the ID of the vehicle, and the length of the field 920 may be 32 bits. The packet type field 930 indicates the type of the packet, and the length of the field 930 may be 4 bits. A segment center (Centre of seg.) field 950 indicates the longitude and latitude of the center of the segment, and the length of the field 950 may be 64 bits (32 bits for longitude and 32 bits for latitude). The LS field 960 indicates the side length of the segment for the RSU, and the length of the field 960 may be 12 bits. The channel field 970 represents a list of channels allocated for the segment, and the length of the field 970 may be (8 bits)*the total number of channels allocated for the segment.

680. After receiving the network segmentation information and channel allocation information from the RSU, the node switches to the LCCH to monitor the control message.

Since there is no congestion in the communication range of the RSU under normal network conditions, the vehicle monitors control messages on the legacy CCH and service data on the legacy SCH. In the congestion state, the vehicle will receive network segment information and corresponding channel allocation information broadcast by RSU on PCCH. After receiving the segmentation information and the corresponding channel allocation information, the vehicle will immediately switch to the corresponding dedicated LCCH to monitor the control messages. In addition, when the updated network segment information and channel allocation information are received again, the vehicle should update its own segment ID (SID) according to the updated network segment information and channel allocation information, and immediately switch to the corresponding Dedicated LCCH to monitor control messages.

Fig. 11 depicts a schematic flowchart of a communication process according to another embodiment of the present invention.

In this embodiment, it is assumed that the RRM server has performed network segmentation and channel allocation for the congested area, and if the congested area becomes uncongested, the network segmentation and channel allocation will be revoked.

1110. The RRM server determines that the congested area becomes uncongested.

Also, as described in 630, the RRM server can identify whether a congested area becomes uncongested based on the number of active nodes (node density) within the communication range of the RSU in the area. For example, if the node density in a certain area is lower than a threshold N _desired (which can be adjusted or preset), then the area identified as congested becomes less congested. Optionally, as another embodiment, thresholds of different communication ranges may be predefined in the RRM server.

1120. The RRM server sends a segment withdrawal packet to the RSU.

After providing the network status information, the RRM server in the NCC determines that the network has become uncongested and thus the previous segment is no longer needed. Therefore, the NCC will send a segment withdraw packet to the RSU to revoke the previous segment and channel assignment.

Figure 12 depicts the format of packets sent from the RRM server to the RSU.

Referring to FIG. 12, the sender ID field 1210 includes the ID of the RRM server, and the length of the field 1210 may be 32 bits. The destination ID field 1220 contains the ID of the RSU, and the length of the field 1220 may be 32 bits. The packet type field 1230 includes the type of the packet, which is used to indicate that the packet is a network segment withdrawal message, and the length of the field 1230 may be 4 bits. The revocation flag field 1240 includes the segment side length of the RSU for indicating that the segment is revoked, and the length of the field 1240 may be 4 bits.

1130. The RSU sends a segment withdrawal packet to the nodes it covers.

After the RSU receives the segment withdrawal packet from the NCC, it broadcasts the same packet to the vehicles within its coverage.

1140. The node switches back to the legacy CCH to monitor the control message.

For example, after the vehicle receives the packet, it will switch back to monitor the legacy CCH and perform medium access based on the multi-channel MAC protocol.

Fig. 14 depicts a schematic diagram of a network model according to an embodiment of the present invention. The scenario in Figure 14 considers networks with multiple hops within a large reference area.

In an example scenario, the performance of the embodiments of the present invention is evaluated in terms of throughput, packet transfer rate and transmission collision rate using the well-known simulation tool NS-2.

For example, the area under consideration is a 500m x 1500m area with traffic in a Manhattan grid pattern, where nodes travel along the grid (ie, representing lanes). Assume that RSU exists in the system model. In urban areas, RSUs are typically used in busy/congested areas (eg, traffic lights). In highway scenarios, RSUs are often placed along popular highways to assist ITS and help collect and disseminate information for various applications. The segmentation mechanism is based on geographic location. Each segment uses an RSU as a local coordinator to help forward packets to distant hops, propagate emergency messages, and serve as a service provider to provide information to ITS service users. It is assumed that the RSU has another network interface (eg Ethernet/LTE) in addition to DSRC access.

Taking into account the different network sizes, i.e. single-hop and multi-hop are evaluated differently. The single-hop scene covers an area of 500m×500m, and the multi-hop scene consists of three single-hop areas. Assuming that an RSU is placed every 500m along the area boundary, as shown in Figure 14, the vehicles are randomly distributed in the grid. The average speed of the nodes is 27mi/h, which is close to the speed limit of the urban traffic scene. The density of nodes in each subnetwork is equal.

The results of the overall throughput versus the total number of nodes in a large-scale reference region show that the DNSM-MAC scheme outperforms other multi-channel MAC schemes from small-scale to large-scale networks except for very sparse networks.

In order to analyze the actual system performance, the middle area is chosen as the reference area, because nodes in this area will naturally receive interference from both sides from nodes outside the area. The results of the normalized throughput of nodes in the intermediate region versus the total number of nodes in the reference region show that, in all dense and sparse networks, the normalized throughput achieved by the DNSM-MAC scheme is higher than that of the other three benchmarks Multi-channel scheme. In a network with 90 nodes, the normalized throughput of the DNSM-MAC scheme is 357% higher than that of AMCP and AMCMAC.

Another result is obtained by comparing the packet transfer rate and collision rate on traffic channels between different multi-channel MAC schemes in a large vehicle environment. The results show that both the DNSM-MAC scheme and the AMCMAC scheme are superior to the other two multi-channel MAC schemes in terms of packet transfer rate and collision rate on traffic channels. Under different network scales, compared with AMCP scheme and IEEE 1609.4 standard, DNSM-MAC scheme and AMCMAC scheme have higher and more stable packet transmission rate on the service channel. For the collision rate on the traffic channel, compared with the AMCP scheme, the proposed scheme achieves a lower collision rate and maintains a collision level similar to the standard IEEE 1609.4.

Another result of the cumulative penetration rate of segmented messages versus the number of times messages are broadcasted for different network scale scenarios is also obtained. It should be noted that, usually after the first two broadcasts of segment information, it can penetrate to more than half of the nodes in most scenarios.

Another result of penetration rate versus time in milliseconds shows that the switching latency between different MAC modes (i.e., AMCMAC scheme and DNSM-MAC scheme) is less than 1ms, and all nodes can be notified of the distribution of the reference network within 2 seconds. part.

The above-mentioned process may be performed by a unit in an apparatus or a software module in a computing device. These devices and computing devices are described in the following sections of this application.

Figure 15 is a simplified block diagram of a server according to an embodiment of the present invention.

The server 1500 includes a receiving unit 1510 , a segmenting unit 1520 , an allocating unit 1530 and a sending unit 1540 .

The receiving unit 1510 is configured to receive network state information sent by at least one RSU, wherein the network state information sent by each RSU of the at least one RSU indicates the density of nodes covered by the RSU. The segmentation unit 1520 is configured to segment the area in the communication network according to the network state information, so as to form at least one segment for the at least one RSU respectively. The allocating unit 1530 is configured to allocate a channel for the at least one segment. The sending unit 1540 is configured to send network segment information and channel allocation information to each RSU in the at least one RSU, where the network segment information indicates a segment of the RSU, and the channel allocation information indicates a channel allocated for the segment, In order for the RSU to communicate with the nodes entering the segment through the channel allocated for the segment.

Optionally, the node density includes the number of nodes within different distances from the RSU, and the server further includes a determining unit 1550 configured to determine the area congestion according to the number of nodes within different distances from the RSU.

Optionally, the determining unit 1550 is further configured to determine that the area becomes uncongested, and the sending unit 1540 is further configured to send segment revocation information to each RSU in the at least one RSU, wherein the segment revocation information indicates the revocation The segmentation and channel assignments are such that the RSU communicates with nodes entering the RSU's coverage over legacy channels.

Optionally, the segment is configured to be divided into a plurality of squares, each with an RSU at the center, the side length _L of the square of RSU(a) is given by:

L _S =min(D _max ,L), where:

D _max = max({D _i | N _i ≤ N _desired (a)}),

where (x _a , y _a ) is the longitude and latitude of RSU(a), N _i is the number of nodes in different ranges of RSU(a), N _desired (a) is the desired node of said square of RSU(a) density.

Optionally, the allocating unit 1530 allocates channels for the at least one segment from one common control channel PCCH, two local control channels LCCH, and four local traffic channels LSCH, wherein the PCCH, one LCCH, and two LSCH, and assign the PCCH, another LCCH, and two other LSCHs to another segment adjacent to this segment.

The server can execute each process of the method shown in FIG. 3 , so details are not repeated here.

Figure 16 is a simplified block diagram of an RSU 1600 according to an embodiment of the invention.

The RSU 1600 includes a sending unit 1610 , a receiving unit 1620 and a communication unit 1630 .

The sending unit 1610 is configured to send network state information to the RRM server, where the network state information indicates the density of nodes covered by the RSU.

The receiving unit 1620 is configured to receive network segment information and channel allocation information sent by the server, wherein the network segment information indicates the segment of the RSU, the channel allocation information indicates the channel allocated for the segment, and the segment is One of the at least one segment for the at least one RSU formed by segmenting the area in the communication network by the RRM server, wherein the sending unit 1610 is also configured to send the network segment information and the channel to the nodes covered by the RSU Assignment information.

The communication unit 1630 is configured to communicate with the nodes in the segment through the channel allocated for the segment.

Optionally, the RSU 1600 further includes an acquisition unit 1640 . The obtaining unit 1640 is configured to obtain network state information according to the reports of the nodes covered by the RSU.

Optionally, the node density includes the number of nodes within different distances from the RSU, and the RSU further includes a determining unit 1650 . The determining unit 1650 is configured to determine the coverage congestion of the RSU according to the number of nodes within different distances from the RSU.

Optionally, the receiving unit 1620 is further configured to receive segment revocation information from the RRM server, wherein the segment revocation information indicates that the segment and channel allocation are revoked, and the communication unit 1630 is further configured to switch to the legacy channel and enter the The RSU's covered nodes communicate.

Optionally, the sending unit 1610 is configured to: the RSU periodically reports the network state information to the NCC; or when at least one of the predetermined conditions is met, the RSU reports the network state information to the NCC.

Optionally, a common control channel PCCH, two local control channels LCCH and four local traffic channels are allocated for the at least one segment, a PCCH, an LCCH and two LSCHs are allocated for the segment, and for the segment Another segment adjacent to the segment allocates the PCCH, another LCCH and two other LSCHs.

The RSU can execute each process of the method shown in FIG. 4 , so details will not be repeated here.

Figure 17 is a simplified block diagram of a node 1700 according to an embodiment of the invention.

The node 1700 includes a receiving unit 1710 , a determining unit 1720 and a communication unit 1730 .

The receiving unit 1710 is configured to receive network segment information and channel allocation information from the RSU, wherein the network segment information indicates the segment of the RSU, the channel allocation information indicates the channel allocated for the segment, and the segment is RRM One of the at least one segment respectively for the at least one RSU formed by segmenting the area in the communication network by the server.

The determining unit 1720 is configured to determine that the node is in the segment according to the network segment information.

The communication unit 1730 is configured to communicate with the RSU through the channel allocated for the segment.

Optionally, the receiving unit 1710 is also configured to receive segment revocation information from the RSU, wherein the segment revocation information indicates that the segment and channel allocation are revoked, and the communication unit 1730 is configured to communicate with the RSU through a legacy channel .

Optionally, a common control channel PCCH, two local control channels LCCH and four local traffic channels are allocated for the at least one segment, a PCCH, an LCCH and two LSCHs are allocated for the segment, and for the segment Another segment adjacent to the segment allocates the PCCH, another LCCH and two other LSCHs.

Optionally, a node is a vehicle including an OBU.

The node can execute each process of the method shown in FIG. 5 , so details are not repeated here.

It should be noted that the server 1500, the RSU 1600 and the node 1700 are presented here in the form of functional units. The term "unit" may refer to an application-specific integrated circuit (ASIC), electronic circuit, processor (shared, dedicated, or group) and memory, combinational logic, and/or to provide the described Other suitable components of the function are used here without limitation. In a specific example, those skilled in the art will appreciate that server 1500, RSU 1600, and node 1700 may take the form of computing device 1800 of FIG. 18 . For example, the determining unit, the allocating unit, the segmenting unit, the acquiring unit, and the communication unit may be implemented by a processor, a storage unit, and a communication interface of the host, and specifically may be implemented by the processor executing a module in the storage unit.

FIG. 18 is a simplified block diagram of a computing device 1800 . The computing device includes a processor 1810 coupled with one or more data storage devices. The data storage device may include a storage medium 1850 and a storage unit 1820 . The storage medium 1850 may be read-only, such as read-only memory (ROM), or read/writable, such as a hard disk or flash memory. The storage unit 1820 may be a random access memory (RAM). The storage unit 1820 may be physically integrated with the processor or inside the processor, or configured as an independent unit or multiple units.

Processor 1810 provides sequencing and processing facilities for executing instructions, performing interrupt actions, providing timing functions, and possibly other functions. Optionally, processor 1810 includes one or more central processing units (CPUs). Optionally, computing device 1800 includes more than one processor. The term "processor" refers to one or more devices, circuits and/or processing cores configured to process data such as computer program instructions.

The program codes executed by the processor 1810 may be stored in the storage unit 1820 or in the storage medium 1850 . Optionally, the program codes stored in the storage medium 1850 may be copied into the storage unit for execution by the processor 1810.

Computing device 1800 also includes communication interface 1860 for communicating directly with another device or system via an external network. Optionally, the computing device 1800 also includes an output device 1830 and an input device 1840 . Output device 1830 is coupled to processor 1810 and can display information in one or more ways. Input device 1840 is also coupled to processor 1810 and capable of receiving input from a user of computing device 1800 in one or more ways.

The above-mentioned elements of the computing device 1800 may be coupled to each other through a bus.

Computing device 1800 may be a general-purpose computing device or an application-specific computing device. As a practical example, the above-mentioned computing device may be a desktop computer, a laptop computer, a web server, a personal digital assistant (PDA), a mobile phone, a tablet computer, a wireless terminal device, a telecommunication device, Embedded system or any other device. However, the present application is of course not limited to any particular type of computing device.

As another embodiment, the present application provides a server. The functionality of the server may be implemented by the computing device described in FIG. 18 .

The server includes: a storage unit storing computer-executable program code, a communication interface, and a processor coupled to the storage unit and the communication interface, wherein the program code includes instructions, and when the processor executes the instructions, the processor: receiving network state information sent by at least one roadside unit RSU, segmenting areas in the communication network according to the network state information to form at least one segment for the at least one RSU, and assigning the at least one segment channel, and send network segment information and channel allocation information to each RSU of the at least one RSU. The network state information sent by each RSU of the at least one RSU indicates the density of nodes covered by the RSU. The network segment information indicates the segment of the RSU, and the channel allocation information indicates the channel allocated for the segment, so that the RSU communicates with the nodes entering the segment through the channel allocated for the segment.

Optionally, the density of the nodes includes the number of nodes within different distances from the RSU, and the program code further includes instructions that, when the processor executes the instructions, cause the processor to The area is congested according to the number of nodes within different distances from the RSU.

Optionally, the program code further includes instructions, which, when executed by the processor, cause the processor to determine that the area becomes uncongested, and send segment withdrawal information to each RSU of the at least one RSU. The segment revocation information indicates that the segment and channel allocation are revoked so that the RSU communicates with the nodes entering the coverage of the RSU through the legacy channel.

According to an embodiment of the present invention, when the processor executes the instruction, the processor is made to divide the area into a plurality of squares, each square has an RSU in the center of the segmentation process, and the side length _L of the square of the RSU (a) is :

L _S =min(D _max ,L), where:

D _max = max({D _i | N _i ≤ N _desired (a)}),

where (x _a , y _a ) is the longitude and latitude of RSU(a), N _i is the number of nodes in different ranges of RSU(a), N _desired (a) is the desired node of said square of RSU(a) density.

According to an embodiment of the present invention, when the processor executes the instruction, the processor is configured to allocate channels for the at least one segment from a common control channel PCCH, two local control channels LCCH and four local traffic channels LSCH, The PCCH, one LCCH and two LSCHs are allocated to the segment, and the PCCH, another LCCH and two other LSCHs are allocated to another segment adjacent to the segment.

The server can execute each process of the method shown in FIG. 3 , so details are not repeated here.

As another embodiment, the present application provides an RSU. The functionality of the RSU may be implemented by the computing device described in FIG. 18 .

The server includes: a storage unit storing computer-executable program code, a communication interface, and a processor coupled to the storage unit and the communication interface, wherein the program code includes instructions, and when the processor executes the instructions, the processor: Send network status information to the radio resource management RRM server, receive network segment information and channel allocation information sent by the server, send network segment information and channel allocation information to the nodes covered by the RSU, and communicate with the channel allocated for the segment The nodes in this segment communicate. The network status information indicates the density of nodes covered by the RSU. The network segment information indicates the segment of the RSU, the channel allocation information indicates the channel allocated for the segment, and the segment is formed by the RRM server segmenting the area in the communication network for the at least one One of at least one segment of the RSU.

Optionally, the program code further includes an instruction, which, when the processor executes the instruction, causes the processor to acquire network status information according to the report of the nodes covered by the RSU.

Optionally, the density of the nodes includes the number of nodes within different distances from the RSU, and the program code further includes instructions, when the processor executes the instructions, the processor sends the network status information to the radio resource management RRM server The coverage congestion of the RSU is determined according to the number of nodes within different distances from the RSU.

Optionally, the program code further includes an instruction, when the processor executes the instruction, the processor receives segment revocation information from the RRM server, and communicates with the node that enters the coverage of the RSU by switching to the legacy channel . The segment revocation information indicates the revocation of the segment and channel allocation.

According to an embodiment of the present invention, when the processor executes the instruction, the processor is made to report the network status information to the NCC periodically, or to report the network status information to the NCC when at least one of the predetermined conditions is met.

According to an embodiment of the present invention, a common control channel PCCH, two local control channels LCCH and four local traffic channels are allocated for the at least one segment, a PCCH, an LCCH and two LSCHs are allocated for the segment, and for Another segment adjacent to this segment allocates the PCCH, another LCCH and two other LSCHs.

The RSU can execute each process of the method shown in FIG. 4 , so details are not repeated here.

As another embodiment, the present application provides a node. The functionality of this node may be implemented by the computing device described in FIG. 18 .

The node includes: a storage unit storing computer-executable program code, a communication interface, and a processor coupled to the storage unit and the communication interface, wherein the program code includes instructions, and when the processor executes the instructions, the processor: Receive network segment information and channel allocation information from the roadside unit RSU, determine that the node is in the segment according to the network segment information, and communicate with the RSU through the channel allocated for the segment. The network segment information indicates the segment of the RSU, the channel allocation information indicates the channel allocated for the segment, and the segment is formed by the RRM server for segmenting the area in the communication network for the at least one RSU One of at least one segment of the .

Optionally, the program code further includes instructions. When the processor executes the instructions, the processor receives segment revocation information from the RRM server and communicates with the RSU through a legacy channel. The segment revocation information indicates the revocation of the segment and channel allocation.

According to an embodiment of the present invention, a common control channel PCCH, two local control channels LCCH and four local traffic channels are allocated for the at least one segment, a PCCH, an LCCH and two LSCHs are allocated for the segment, and for Another segment adjacent to this segment allocates the PCCH, another LCCH and two other LSCHs.

According to an embodiment of the invention, the node is a vehicle comprising an on-board unit OBU.

The node can execute each process of the method shown in FIG. 5 , so details are not repeated here.

According to the above embodiments of the present invention, the RRM server performs network segmentation and channel allocation for the segments according to the network status information reported by the RSU, and notifies the RSU of the network segmentation information and channel allocation information, so that the RSU The channel allocated for the segment communicates with the nodes entering the segment, thereby reducing the probability of collision and quality degradation, thereby improving the utilization rate of wireless resources.

Those skilled in the art can clearly understand that for the convenience and brevity of the description, the specific working process of the above-described system, device and unit can refer to the corresponding process in the foregoing method embodiment, which will not be repeated here.

In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods may be implemented in other ways. For example, the device embodiments described above are only illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or May be integrated into another system, or some features may be ignored, or not implemented. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces, and the indirect coupling or communication connection of devices or units may be in electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place, or may be distributed to multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, each unit may exist separately physically, or two or more units may be integrated into one unit. An integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

When the integrated unit is realized in the form of a software function unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, the essence of the technical solution of the present invention or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of software products. The computer software product is stored in a storage medium, and includes several instructions for making a computer device (which may be a personal computer, a server network device, etc.) execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: a USB flash drive, a removable hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and the like that can store program codes.

The transmit diversity method, related equipment and system according to the present invention have been described in detail above. Based on the spirit of the embodiments of the present invention, those skilled in the art may modify the specific implementation manner and application scope of the present invention. Therefore, the contents of the specification should not be construed as limiting the present invention.

If the functions described above are realized in the form of software function units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or the part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including Several instructions are used to make a computer device (which may be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), magnetic disk or optical disk and other media that can store program codes. .

The above is only a specific implementation of the application, but the scope of protection of the application is not limited thereto. Anyone familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the application. Should be covered within the protection scope of this application. Therefore, the protection scope of the present application should be determined by the protection scope of the claims.

Claims (24)

1. A method of communication, comprising:

receiving network state information sent by at least one RSU (road side unit), by a RRM (radio resource management) server, wherein the network state information sent by each RSU in the at least one RSU indicates the density of nodes covered by the RSU;

the RRM server segmenting regions in the communication network according to the network state information to form at least one segment for the at least one RSU, respectively;

the RRM server allocates a channel for the at least one segment;

the RRM server transmitting network segment information and channel allocation information to each of the at least one RSU, wherein the network segment information indicates a segment of the RSU and the channel allocation information indicates a channel allocated for the segment so that the RSU communicates with a node entering the segment through the channel allocated for the segment;

wherein the density of nodes comprises a number of nodes within different distances from the RSU, and before the RRM server segments a region in the communication network, the method further comprises:

and the RRM server determines the region congestion according to the number of nodes in different distances from the RSU.

2. The method of claim 1, further comprising:

the RRM server determining that the area becomes uncongested;

the RRM server sends segment revocation information to each of the at least one RSU, wherein the segment revocation information indicates that the segment and channel allocation are revoked so that the RSU communicates with nodes entering the coverage of the RSU through a legacy channel.

3. The method of claim 1, wherein the RRM server segments the regions in the communication network according to the network state information, comprising:

the RRM server divides the area into a plurality of squares, each square having an RSU at the center, the side length L of the square of RSU (a)_SComprises the following steps:

L_S＝min(D_max,L)

wherein,

wherein (x)_a,y_a) Longitude and latitude, N, of RSU (a)_iIs the number of nodes, N, in different ranges of the RSU (a)_desired(a) Is the desired node density of said square of RSU (a), dist () denotes the distance between the nodes, D_iRepresenting different distances to the rsu (a) at said different ranges.

4. The method of any of claims 1-3, wherein the allocating channels for the at least one segment comprises:

allocating channels for said at least one segment from among one common control channel PCCH, two local control channels LCCH and four local traffic channels LSCH, wherein said PCCH, one LCCH and two LSCHs are allocated for said segment and said PCCH, one other LCCH and two other LSCHs are allocated for another segment adjacent to said segment.

5. A method of transmitting data, comprising:

the method comprises the steps that a RSU sends network state information to a RRM server, wherein the network state information indicates the density of nodes covered by the RSU;

the RSU receives network segment information and channel allocation information transmitted by a server, wherein the network segment information indicates a segment of the RSU, the channel allocation information indicates a channel allocated for the segment, and the segment is one of at least one segment formed by segmenting a region in a communication network by the RRM server and aiming at least one RSU respectively;

the RSU sends network segmentation information and the channel allocation information to nodes covered by the RSU;

the RSU communicates with nodes in the segment over the channel allocated for the segment;

further comprising:

and the RSU acquires network state information according to the report of the node covered by the RSU.

6. The method of claim 5, wherein the density of nodes comprises a number of nodes within different distances from the RSU, and before the RSU sends network status information to the RRM server, the method further comprises:

and the RSU determines the coverage area congestion of the RSU according to the number of nodes in different distances from the RSU.

7. The method of claim 6, further comprising:

the RSU receiving segment revocation information from the RRM server, wherein the segment revocation information indicates that the segment and channel allocation are revoked;

the RSU communicates with nodes that enter the RSU's coverage by switching to legacy channels.

8. The method of claim 5, wherein the transmitting network status information by the Road Side Unit (RSU) to a Radio Resource Management (RRM) server comprises:

the RSU periodically reports the network state information to a Network Control Center (NCC); or

The RSU reports the network status information to the NCC when at least one of predetermined conditions is met.

9. The method according to any of claims 5 to 8, wherein said at least one segment is allocated one common control channel, PCCH, two local control channels, LCCH, and four local traffic channels, LSCH, one PCCH, one LCCH, and two LSCH for said segment, and another segment adjacent to said segment is allocated said PCCH, another LCCH, and another two LSCH.

10. A method of transmitting data, comprising:

a node receives network segment information and channel allocation information from a Road Side Unit (RSU), wherein the network segment information indicates a segment of the RSU, the channel allocation information indicates a channel allocated for the segment, and the segment is one of at least one segment formed by a Radio Resource Management (RRM) server segmenting a region in a communication network and aiming at least one RSU;

the node determines that the node is in the segment according to the network segment information;

the node communicating with the RSU over the channel allocated for the segment;

further comprising:

the node receiving segment revocation information from the RSU, wherein the segment revocation information indicates that the segment and channel allocation are revoked;

the node communicates with the RSU over a legacy channel.

11. The method of claim 10, wherein the at least one segment is allocated one common control channel PCCH, two local control channels LCCH and four local traffic channels LSCH, the segment is allocated one PCCH, one LCCH and two LSCHs, and another segment adjacent to the segment is allocated the PCCH, another LCCH and another two LSCHs.

12. The method according to claim 10 or 11, wherein the node is a vehicle comprising an on board unit, OBU.

13. A server, comprising:

a receiving unit configured to receive network status information transmitted by at least one Road Side Unit (RSU), wherein the network status information transmitted by each RSU of the at least one RSU indicates a density of nodes covered by the RSU;

a segmentation unit configured to segment a region in the communication network according to the network state information to form at least one segment for the at least one RSU, respectively;

an allocation unit configured to allocate a channel for the at least one segment;

a transmitting unit configured to transmit network segment information and channel allocation information to each RSU of the at least one RSU, wherein the network segment information indicates a segment of the RSU, and the channel allocation information indicates a channel allocated for the segment, so that the RSU communicates with a node entering the segment through the channel allocated for the segment;

wherein the density of the nodes comprises the number of nodes within different distances from the RSU, and the server further comprises a determining unit configured to determine the zone congestion according to the number of nodes within different distances from the RSU.

14. The server according to claim 13, wherein the determining unit is further configured to determine that the area becomes uncongested, the transmitting unit is further configured to transmit segment revocation information to each of the at least one RSU, wherein the segment revocation information indicates that the segment and channel allocation are revoked so that the RSU communicates with nodes entering coverage of the RSU over legacy channels.

15. The server of claim 13, wherein the segment is configured to be divided into a plurality of squares, each square having an RSU at the center, the RSU (a) square having a side length L_SComprises the following steps:

L_S＝min(D_max,L)

wherein,

wherein (x)_a,y_a) Longitude and latitude, N, of RSU (a)_iIs the number of nodes, N, in different ranges of the RSU (a)_desired(a) Is the desired node density of said square of RSU (a), dist () denotes the distance between the nodes, D_iRepresenting different distances to the rsu (a) at said different ranges.

16. The server according to any of claims 13 to 15, wherein the allocating unit allocates channels for the at least one segment from one common control channel, PCCH, two local control channels, LCCH, and four local traffic channels, LSCH, wherein the PCCH, one LCCH, and two LSCHs are allocated for the segment, and the PCCH, another LCCH, and another two LSCHs are allocated for another segment adjacent to the segment.

17. A roadside unit comprising:

a transmitting unit configured to transmit network state information to a radio resource management RRM server, wherein the network state information indicates a density of nodes covered by the RSU;

a receiving unit configured to receive network segment information and channel allocation information transmitted by a server, wherein the network segment information indicates a segment of the RSU, the channel allocation information indicates a channel allocated for the segment, and the segment is one of at least one segment respectively for at least one RSU formed by segmenting a region in a communication network by the RRM server, wherein the transmitting unit is further configured to transmit the network segment information and the channel allocation information to nodes covered by the RSU;

a communication unit configured to communicate with nodes in the segment through the channel allocated for the segment;

further comprising:

and the acquisition unit is configured to acquire the network state information according to the report of the node covered by the RSU.

18. The RSU of claim 17, wherein the density of nodes comprises a number of nodes within different distances from the RSU, and further comprising:

and the determining unit is configured to determine the coverage area congestion of the RSU according to the number of nodes in different distances from the RSU.

19. The road side unit of claim 18, wherein the receiving unit is further configured to receive segment revocation information from the RRM server, wherein the segment revocation information indicates that the segments and channel allocations are revoked, and the communication unit is further configured to communicate with nodes that enter coverage of the RSU by switching to legacy channels.

20. The roadside unit of claim 17, wherein the transmitting unit is configured to: the RSU periodically reports the network state information to a Network Control Center (NCC); or at least one of predetermined conditions is met, the RSU reports the network status information to the NCC.

21. The rsu of any of claims 17-20, wherein the at least one segment is allocated one common control channel, PCCH, two local control channels, LCCH, and four local traffic channels, LSCH, one PCCH, one LCCH, and two LSCHs, for the segment, and another segment adjacent to the segment is allocated the PCCH, another LCCH, and another two LSCHs.

22. A communication node, comprising:

a receiving unit configured to receive network segment information and channel allocation information from a road side unit, RSU, wherein the network segment information indicates a segment of the RSU, the channel allocation information indicates a channel allocated for the segment, and the segment is one of at least one segment respectively for at least one RSU formed by a RRM server segmenting a region in a communication network;

a determining unit configured to determine that the node is in the segment according to the network segment information;

a communication unit configured to communicate with the RSU through the channel allocated for the segment;

wherein the receiving unit is further configured to receive segment revocation information from the RSU, wherein the segment revocation information indicates that the segment and channel allocation are revoked, and the communication unit is further configured to communicate with the RSU over a legacy channel.

23. The node of claim 22, wherein the at least one segment is allocated one common control channel, PCCH, two local control channels, LCCH, and four local traffic channels, LSCH, one PCCH, one LCCH, and two LSCHs are allocated for the segment, and another segment adjacent to the segment is allocated the PCCH, another LCCH, and another two LSCHs.

24. A node according to claim 22 or 23, wherein said node is a vehicle comprising an on board unit, OBU.