A multi-potential forwarding node transmission method based on NDN and vehicle coordinates in Internet of Vehicles

Abstract

The present invention discloses a multi-potential forwarding node transmission method based on NDN and vehicle coordinates in an Internet of Vehicles, which is particularly suitable for networks with high node mobility such as Internet of Vehicles. This invention aims at the problem that there is only a unique next-hop forwarding node in the traditional TCP / IP Internet of Vehicles transmission path, which easily causes unstable transmission. A method for constructing multiple potential forwarding nodes for content transmission based on the content-oriented nature of NDN and vehicle coordinate information is proposed. By extending the PIT table and FIB table in the Internet of Vehicles based on NDN, the coordinate information of multiple potential forwarding nodes is recorded in the PIT table and the FIB table for forwarding data packets and interest packets respectively; and the master forwarding node and the slave forwarding node are specified according to the coordinate information of the vehicle, and the forwarding is staggered or canceled by monitoring and setting random time to avoid transmission redundancy and conflict; finally, a dynamic multi-potential forwarding node path is constructed in the Internet of Vehicles to improve the content transmission performance of the Internet of Vehicles.

Description

Technical Field

[0001] The present invention relates to the field of wireless multi-hop networks, and more specifically to a method for content transmission in a vehicle network with high node mobility. More specifically, it relates to a method for transmitting multiple potential forwarding nodes based on NDN and vehicle coordinates by utilizing the content-oriented concept of an NDN network and based on vehicle coordinate information. Background Art

[0002] With the development of Internet technology, wireless connection to the Internet has gradually become the main way to access the Internet. The Internet of Vehicles can realize intelligent traffic management, intelligent dynamic information services and intelligent vehicle control, and is a typical application of Internet of Things technology in the field of transportation systems; and realizing efficient content transmission in the Internet of Vehicles is the basis of various functions of the Internet of Vehicles.

[0003] In Internet of Vehicles applications such as in-car entertainment and smart transportation, mobile vehicles generally act as requesters of network content and need to request content from other vehicles or roadside infrastructure in the network. Other vehicles and roadside infrastructure may be within one hop or may require multiple hops for transmission.

[0004] However, the current typical implementation of the Internet of Vehicles is based on the TCP / IP protocol, which is not suitable for highly mobile wireless networks such as the Internet of Vehicles. The protocols used in current wireless networks are generally transplanted directly from IP-based wired networks. For example, in content transmission, IP-based unicast is generally used for content transmission. Unicast transmission requires selecting an optimal node sequence between the source node and the destination node and forwarding each packet through this sequence. It cannot fully utilize the natural broadcast characteristics of wireless networks, and due to the mobility of nodes, the unicast path may be frequently interrupted. Summary of the invention

[0005] The purpose of the present invention is to solve the above problems in the prior art and to propose a multi-potential forwarding node transmission method based on NDN and vehicle coordinates in the Internet of Vehicles.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A method for transmitting content in multiple potential forwarding nodes based on NDN and vehicle coordinates in an Internet of Vehicles, the method comprising the following steps:

[0008] S1. Expand the PIT table and FIB table in the NDN-based Internet of Vehicles. In the PIT table and FIB table, respectively, forward data packets and interest packets, and record the coordinate information of multiple potential forwarding nodes;

[0009] S2. The content requester vehicle broadcasts the interest packet for searching the content. The vehicles in the network forward the interest packet for searching the content in a restricted broadcast manner until the content provider receives the interest packet or the interest packet exceeds the maximum forwarding hop count. All vehicles that forward the interest packet for searching the content are recorded as forwarding vehicles, and the information of the interest packet is added to the PIT table during the forwarding process.

[0010] S3. After receiving the interest packet, the content provider returns a data packet without a payload. All forwarding vehicles must forward the data packet and add the information of the data packet to the FIB table during the forwarding process.

[0011] S4. During the forwarding process of the data packet without payload, each neighbor forwarding vehicle of the forwarding vehicle collects the coordinate information of the upstream and downstream neighbor forwarding vehicles from the forwarded data packet, and adds the coordinate information of the upstream (vehicle close to the content provider) neighbor forwarding vehicle into the FIB table, and adds the coordinate information of the downstream (vehicle close to the content requester) neighbor forwarding vehicle into the PIT table;

[0012] S5. If the content requester receives data packets without payload sent by multiple providers, it selects one with the smallest hop count as the content provider and sends an interest packet to the content provider to request the data packet.

[0013] S6. The interest packet is forwarded in the following way until the content provider arrives: the content requester or forwarding vehicle as the sending node randomly selects one as the main forwarding node from multiple potential forwarding nodes in its own FIB table, adds its coordinate information to the interest packet, and then sends the interest packet; if the forwarding vehicle that receives the interest packet is the main forwarding node, go to step S6.1; if it is the slave forwarding node, go to step S6.2; otherwise, the forwarding vehicle cancels forwarding the interest packet;

[0014] S6.1. The current forwarding vehicle becomes the sending vehicle and immediately forwards the interest packet;

[0015] S6.2. Wait for a random time T. If, during the random time, the forwarding vehicle hears that other nodes closer to or at the same distance from the provider continue to forward the interest packet, it stops forwarding, otherwise it continues forwarding;

[0016] S7. After receiving the interest packet, the content provider returns the corresponding data packet;

[0017] S8. The data packet adopts the following forwarding method until the content requester: the content provider or forwarding vehicle as the sending node randomly selects one as the main forwarding node from multiple potential forwarding nodes in its own PIT table, adds its coordinate information to the data packet, and then sends the data packet; if the main forwarding node receives the data packet, go to step S8.1, if it is a slave forwarding node, go to step S8.2, otherwise the forwarding vehicle cancels forwarding the data packet;

[0018] S8.1. The current forwarding vehicle becomes the sending vehicle and immediately forwards the data packet;

[0019] S8.2. Wait for a random time T. If, during the random time, the forwarding vehicle hears that other nodes that are closer to or at the same distance from the requester continue to forward the data packet, it stops forwarding, otherwise it continues forwarding.

[0020] Furthermore, the PIT table records “content name”, “requester ID”, “requester hop count” and “list of potential forwarding nodes for data packets”, and the FIB table records “content name”, “provider ID”, “provider hop count” and “list of potential forwarding nodes for interest packets”.

[0021] Furthermore, the interest packet for searching the content includes information such as "content name", "requester ID", "requester hop count" and "remaining maximum forwarding hop count". When forwarding the interest packet, the forwarding vehicle adds the "content name", "requester ID" and "requester hop count" information to the PIT table, adds 1 to the "requester hop count" in the interest packet, subtracts 1 from the "remaining maximum forwarding hop count" and then forwards the interest packet.

[0022] Furthermore, the data packet without payload contains information such as "content name", "requester ID", "requester hop count", "provider ID", "provider hop count", "forwarding vehicle ID" and "forwarding vehicle coordinates". When forwarding the data packet, the forwarding vehicle adds the "content name", "provider ID" and "provider hop count" information to the FIB table, subtracts 1 from the "requester hop count" in the data packet, adds 1 to the "provider hop count" and then forwards the data packet.

[0023] Furthermore, when a forwarding vehicle forwards a data packet without a payload, all neighboring forwarding vehicles will collect the identification and coordinate information of the forwarding vehicle by listening to the data packet without a payload. If the forwarding vehicle that sends the data packet is closer to the content provider than the forwarding vehicle that receives the data packet, the neighboring vehicle will record the coordinate information of the forwarding vehicle that sends the data packet in the FIB table; if the forwarding vehicle that sends the data packet is closer to the content requester than the neighboring forwarding vehicle that receives the data packet, it will be recorded in the PIT table.

[0024] Furthermore, if the coordinates of the main forwarding node specified in the interest packet or data packet received by the forwarding vehicle are the coordinates of the vehicle when forwarding the data packet without load, then the vehicle is the main forwarding node for this forwarding.

[0025] Furthermore, if the geometric distance between the forwarding vehicle and the main forwarding node in the received interest packet or data packet is denoted as D, and satisfies: D≤0.5R, where R is the transmission distance of the wireless signal, then the forwarding vehicle is a slave forwarding node.

[0026] Furthermore, the random time to wait after receiving an interest packet or a data packet from a forwarding node is:

[0027] T=random{1,W}*slotTime (1)

[0028] Among them, W is a fixed integer (such as 100), random{1,W} represents a random integer between 1 and W, and slotTime is the unit backoff duration of the IEEE 802.11p protocol adopted by the Internet of Vehicles at the link layer.

[0029] Compared with the prior art, the present invention has the following advantages and effects:

[0030] (1) The Internet of Vehicles in the present invention can use broadcasting to transmit content, thereby increasing the robustness of the transmission link.

[0031] (2) The present invention constructs a dynamic multi-potential forwarding node path in the Internet of Vehicles to improve the content transmission performance of the Internet of Vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of vehicle networking content transmission of the present invention;

[0033] Figure 2 The present invention expands the PIT table and FIB table of potential forwarding nodes. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] Example

[0036] like Figure 1The schematic diagram of the content transmission process in the Internet of Vehicles shows that node R is the content requester node, and node P is the provider node that caches the target content.

[0037] In the content search phase, the requester R broadcasts the content search interest packet; the interest packet is forwarded in the network in a restricted broadcast manner; when the neighbor node receives the interest packet, it waits for a random time T:

[0038] T=random{1,W}*slotTime (1)

[0039] Among them, W is a fixed integer (such as 100), random{1,W} represents a random integer between 1 and W, and slotTime is the unit backoff duration of the IEEE 802.11p protocol adopted by the Internet of Vehicles at the link layer.

[0040] For example, if R's neighbor nodes A1, A2, A3, A4, and A5 all receive the interest packet, they wait for random times T(A1), T(A2), T(A3), T(A4), and T(A5) respectively. During this period, A1, A2, and A3 do not hear that other nodes have forwarded the interest packet, so they continue to forward it after T(A1), T(A2), and T(A3) time has passed, and in their PIT tables (such as Figure 2 (a)) Record "content name", "requester ID" and "number of hops from requester R" (number of hops is 1); and A4 and A5 listen to other nodes sending the interest packet at T(A4) and T(A5), so they cancel forwarding. Similarly, after B1, B2 and B3 receive the interest packet, they record the relevant information in the PIT table and continue forwarding according to the above mechanism until the provider node P.

[0041] During the content search interest packet forwarding process, A1, A2, A3, B1, B2 and B3 forwarded the interest packet, and they are the forwarding vehicles.

[0042] After receiving the interest packet, the provider P returns a data packet without a payload. Only the forwarding vehicle (i.e., the vehicle that has forwarded the interest packet for the search content) will forward the data packet and, when forwarding, add the packet to their FIB table (e.g. Figure 2 (b)) records information such as "content name", "provider ID" and "provider hop count".

[0043] During the forwarding process of the data packet without payload, the neighbor forwarding vehicles of the forwarding vehicle record the coordinate information of the potential forwarding node. For example, when vehicle B1 forwards the data packet without payload, p, B2, B3, A1, A2 and A3 are all neighbor forwarding vehicles. They know from the data packet without payload forwarded by B1 that: 1) B1 has the same number of hops from the requester and provider as B2 and B3, so they do not record B1 as a potential forwarding node; 2) B1 is the next hop forwarding vehicle of P, so P records the vehicle coordinates of B1 in the PIT table; B1 is the upstream neighbor forwarding vehicle of A1, A2 and A3, so A1, A2 and A3 have the vehicle coordinates of B1 in the FIB table.

[0044] In the content transfer phase, the requester sends an interest packet and the provider returns the corresponding data packet with payload.

[0045] like Figure 1 As shown, the requester R sends an interest packet to the provider, and the forwarding vehicles in the network transmit it using a broadcast method based on vehicle coordinates.

[0046] For example, the interest packet sent by the content requester vehicle R specifies A3 as the main forwarding node, then:

[0047] 1) If A3 can receive the interest packet, A3 will immediately forward the interest packet;

[0048] 2) If A1 receives the interest packet, it finds that the distance between itself and A3 is greater than 0.5R through the coordinates of A3 in the interest packet, so A1 cancels the forwarding;

[0049] 3) If A2 receives the interest packet, it finds that its distance from A3 is less than 0.5R through the coordinates of A3 in the interest packet, so A2 waits for a random time T:

[0050] T=random{1,W}*slotTime (1)

[0051] Where W is a fixed integer (such as 100), random{1, W} represents a random integer between 1 and W, and slotTime is the unit backoff duration of the IEEE 802.11p protocol adopted by the Internet of Vehicles at the link layer. A2 detects that A3 has forwarded the interest packet during the waiting time, so it cancels the forwarding.

[0052] All forwarding vehicles forward the interest packets according to the above rules until they reach the content provider node.

[0053] After receiving the interest packet, the provider P node returns the corresponding data packet with payload, which is transmitted using the following broadcast method based on vehicle coordinates.

[0054] For example, the data packet sent by the content provider vehicle P specifies B3 as the main forwarding node, then:

[0055] 1) If B3 can receive the data packet, B3 will forward the data packet immediately;

[0056] 2) If B1 and B2 receive the data packet, they find that their distance from B3 is less than 0.5R through the coordinates of B3 in the data packet, so B1 and B2 wait for a random time T:

[0057] T=random{1,W}*slotTime (1)

[0058] Where W is a fixed integer (such as 100), random{1,W} represents a random integer between 1 and W, and slotTime is the unit backoff duration of the IEEE 802.11p protocol adopted by the Internet of Vehicles at the link layer. B1 and B2 hear that B3 has forwarded the interest packet during the waiting time, so they cancel the forwarding.

[0059] All forwarding nodes forward the data packet according to the above rules until it reaches the requester node.

[0060] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention shall be equivalent replacement methods and shall be included in the protection scope of the present invention.

Claims

1. A multi-potential forwarding node transmission method based on NDN and vehicle coordinates in a vehicle network, characterized in that: The transmission method comprises the following steps: S1. Expand the PIT table and FIB table in the NDN-based Internet of Vehicles. In the PIT table and FIB table, respectively, forward data packets and interest packets, and record the coordinate information of multiple potential forwarding nodes; S2. The content requester vehicle broadcasts the interest packet for searching the content. The vehicles in the network forward the interest packet for searching the content in a restricted broadcast manner until the content provider receives the interest packet or the interest packet exceeds the maximum forwarding hop count. All vehicles that forward the interest packet for searching the content are recorded as forwarding vehicles, and the information of the interest packet is added to the PIT table during the forwarding process. S3. After receiving the interest packet, the content provider returns a data packet without a payload. All forwarding vehicles must forward the data packet and add the information of the data packet to the FIB table during the forwarding process. S4. During the forwarding process of the data packet without payload, each neighbor forwarding vehicle of the forwarding vehicle collects the coordinate information of the upstream and downstream neighbor forwarding vehicles from the forwarded data packet, and adds the coordinate information of the upstream (vehicle close to the content provider) neighbor forwarding vehicle into the FIB table, and adds the coordinate information of the downstream (vehicle close to the content requester) neighbor forwarding vehicle into the PIT table; S5. If the content requester receives data packets without payload sent by multiple providers, it selects one with the smallest hop count as the content provider and sends an interest packet to the content provider to request the data packet. S6. The interest packet is forwarded in the following way until the content provider arrives: the content requester or forwarding vehicle as the sending node randomly selects one as the main forwarding node from multiple potential forwarding nodes in its own FIB table, adds its coordinate information to the interest packet, and then sends the interest packet; if the forwarding vehicle that receives the interest packet is the main forwarding node, go to step S6.1; if it is the slave forwarding node, go to step S6.2; otherwise, the forwarding vehicle cancels forwarding the interest packet; S6.

1. The current forwarding vehicle becomes the sending vehicle and immediately forwards the interest packet; S6.

2. Wait for a random time T. If, during the random time, the forwarding vehicle hears that other nodes closer to or at the same distance from the provider continue to forward the interest packet, it stops forwarding, otherwise it continues forwarding; S7. After receiving the interest packet, the content provider returns the corresponding data packet; S8. The data packet adopts the following forwarding method until the content requester: the content provider or forwarding vehicle as the sending node randomly selects one as the main forwarding node from multiple potential forwarding nodes in its own PIT table, adds its coordinate information to the data packet, and then sends the data packet; if the main forwarding node receives the data packet, go to step S8.1, if it is a slave forwarding node, go to step S8.2, otherwise the forwarding vehicle cancels forwarding the data packet; S8.

1. The current forwarding vehicle becomes the sending vehicle and immediately forwards the data packet; S8.

2. Wait for a random time T. If, during the random time, the forwarding vehicle hears that other nodes that are closer to or at the same distance from the requester continue to forward the data packet, it stops forwarding, otherwise it continues forwarding.

2. According to claim 1, a multi-potential forwarding node transmission method based on NDN and vehicle coordinates in a vehicle network is characterized in that: The PIT table records "content name", "requester ID", "requester hop count" and "list of potential forwarding nodes for data packets", and the FIB table records "content name", "provider ID", "provider hop count" and "list of potential forwarding nodes for interest packets".

3. According to claim 1, a multi-potential forwarding node transmission method based on NDN and vehicle coordinates in a vehicle network is characterized in that: The interest packet for searching content contains information such as "content name", "requester identifier", "requester hop count" and "remaining maximum forwarding hop count". When forwarding the interest packet, the forwarding vehicle adds the "content name", "requester identifier" and "requester hop count" information to the PIT table, adds 1 to the "requester hop count" in the interest packet, subtracts 1 from the "remaining maximum forwarding hop count" and then forwards the interest packet.

4. According to claim 1, a multi-potential forwarding node transmission method based on NDN and vehicle coordinates in a vehicle network is characterized in that: The data packet without payload contains information such as "content name", "requester ID", "requester hop count", "provider ID", "provider hop count", "forwarding vehicle ID" and "forwarding vehicle coordinates". When forwarding the data packet, the forwarding vehicle adds the "content name", "provider ID" and "provider hop count" information to the FIB table, subtracts 1 from the "requester hop count" and adds 1 to the "provider hop count" in the data packet, and then forwards the data packet.

5. According to claim 1, a multi-potential forwarding node transmission method based on NDN and vehicle coordinates in a vehicle network is characterized in that: When a forwarding vehicle forwards a data packet without a payload, all neighboring forwarding vehicles will collect the forwarding vehicle's identification and coordinate information by listening to the data packet without a payload. If the forwarding vehicle that sends the data packet is closer to the content provider than the forwarding vehicle that receives the data packet, the neighboring vehicle will record the coordinate information of the forwarding vehicle that sends the data packet in the FIB table; if the forwarding vehicle that sends the data packet is closer to the content requester than the neighboring forwarding vehicle that receives the data packet, it will be recorded in the PIT table.

6. The method for transmitting multiple potential forwarding nodes in a vehicle network based on NDN and vehicle coordinates according to claim 1, characterized in that: If the coordinates of the primary forwarding node specified in the interest packet or data packet received by the forwarding vehicle are the coordinates of this vehicle when forwarding the data packet without payload, then this vehicle is the primary forwarding node for this forwarding.

7. The method for transmitting multiple potential forwarding nodes in a vehicle network based on NDN and vehicle coordinates according to claim 1, characterized in that: If the geometric distance between the forwarding vehicle and the main forwarding node in the received interest packet or data packet is recorded as D, and satisfies: D≤0.5R, where R is the transmission distance of the wireless signal, then the forwarding vehicle is a slave forwarding node.

8. The method for transmitting multiple potential forwarding nodes in a vehicle network based on NDN and vehicle coordinates according to claim 1, characterized in that: The random time to wait after receiving an interest packet or a data packet from a forwarding node is: T=random{1,W}*slotTime (1) Among them, W is a fixed integer (such as 100), random{1, W} represents a random integer between 1 and W, and slotTime is the unit backoff duration of the IEEE 802.11p protocol adopted by the Internet of Vehicles at the link layer.

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