Method and system for recovery of loss frames in an operated network

Abstract

The invention discloses a method for recovering a lost frame in an airborne network, which comprises the following steps of: performing time marking on the lost frame between a transmitting end and a receiving end in the airborne network, the lost frame representing a frame which is not correctly received or processed in a bandwidth allocation interval (BAG); creating a virtual link for the lost frame; based on the predicted transmission time T of the lost frame and the round-trip time RTT of the sending end and the receiving end, determining whether fragmentation processing needs to be carried out on the lost frame, wherein the predicted transmission time T comprises a time period from the time when the lost frame is marked to the time when the receiving end receives the lost frame; when it is determined that fragmentation processing needs to be carried out on the lost frame, the lost frame is fragmented into a specific number of fragments; transmitting a specific number of fragments to a receiving end through a virtual link; and recovering the lost frame according to the fragment received by the receiving end. Systems and computer media for restoring lost frames in an onboard network are also disclosed.

Description

Technical Field

[0001] The present invention relates to the field of avionics technology, and more particularly to a method and system for recovering lost frames in an airborne network. Background Art

[0002] AFDX (Avionics Full-Duplex Switched Ethernet) is often used in avionics systems for in-flight communications. AFDX is a high-speed Ethernet protocol that uses full-duplex switched Ethernet to achieve high reliability and low latency data transmission. However, although AFDX was originally designed to improve reliability and reduce frame loss, frame loss may still occur in actual applications.

[0003] When network traffic exceeds the processing capacity of the switch or onboard network, network congestion occurs, resulting in data frame loss. At the same time, incorrect network configuration (such as port configuration or bandwidth allocation) may also cause data frame loss.

[0004] The current frame loss in the onboard network will increase the risk factor of flight safety. In addition, the handshake retransmission between the sender and the receiver cannot guarantee that the lost frame will be successfully received through retransmission. Even if the lost frame can be successfully received by the receiver through retransmission, it cannot be guaranteed that the receiver can receive the lost frame in a reasonable time. This makes it impossible to ensure the timely provision of data frames at all times during the flight of the aircraft. During the flight of the aircraft, the loss of key flight data (data frames) will reduce the safety margin of the aircraft.

[0005] There are very few existing methods for recovering lost data frames on aircraft, including network monitoring and management, equipment redundancy, handshake retransmission, etc. These methods cannot restore lost frames in a timely and reliable manner.

[0006] In view of the above, it is desirable to provide an improved method and system for recovering from lost frames in an airborne network. Summary of the invention

[0007] A brief summary of one or more aspects is given below to provide a basic understanding of these aspects. This summary is not an exhaustive overview of all conceived aspects, and is neither intended to identify the key or critical elements of all aspects nor to define the scope of any or all aspects. Its only purpose is to give some concepts of one or more aspects in a simplified form as a prelude to a more detailed description that will be given later.

[0008] The present invention provides a method for recovering lost frames in an airborne network, including: time-stamping lost frames between a sending end and a receiving end in the airborne network, where the lost frames represent frames that are not correctly received or processed within a bandwidth allocation gap (BAG); creating a virtual link for the lost frames; determining whether to fragment the lost frames based on the estimated transmission time T of the lost frames and the round-trip time RTT between the sending end and the receiving end, where the estimated transmission time T includes the time period from the time when the lost frames are marked to the time when it is estimated that the receiving end receives the lost frames; in the case where it is determined that the lost frames need to be fragmented, cutting the lost frames into a specific number of fragments; transmitting the specific number of fragments to the receiving end through the virtual link; and recovering the lost frames according to the fragments received by the receiving end.

[0009] In some embodiments, the method further includes: determining the priority of lost frames based on the chronological order of the time when the lost frames are marked; and scheduling the retransmission of lost frames according to the priority.

[0010] In some embodiments, determining whether to fragment the lost frames based on the estimated transmission time T of the lost frames and the round-trip time RTT between the sending end and the receiving end further includes: if T < RTT, determining that there is no need to fragment the lost frames; and if T ≥ RTT, determining that it is necessary to fragment the lost frames.

[0011] In some embodiments, the method further includes: in the case where it is determined that there is no need to fragment the lost frames, retransmitting the lost frames to the receiving end through the virtual link.

[0012] In some embodiments, the method further includes: determining whether any of the fragments in the specific number of fragments is lost during transmission based on the frame headers of each of all the fragments received by the receiving end, where the frame header of each fragment includes the frame sequence number of the frame to which the fragment belongs, the total number of fragments, and the fragment sequence number; if there are lost fragments, fragmenting the lost fragments to obtain sub-fragments; and retransmitting the sub-fragments to the receiving end until the receiving end receives the specific number of fragments.

[0013] In some embodiments, the method further includes: sorting all the received fragments according to the total number of fragments, frame sequence number, and fragment sequence number included in the frame headers of the fragments received by the receiving end; and packetizing the sorted fragments to recover the lost frames.

[0014] In some embodiments, creating a virtual link for the lost frames further includes: creating new UDP addresses and new communication ports for the sending end and the receiving end, and keeping the MAC addresses and IP addresses of the sending end and the receiving end unchanged.

[0015] In some embodiments, each of a specific number of fragments occupies a new UDP address and a new communication port, and releases the corresponding UDP address and communication port after the fragment is received at the receiving end.

[0016] The present invention also provides a system for recovering lost frames in an airborne network, including: a time marking module configured to: mark the time of lost frames between a sending end and a receiving end in the airborne network, where the lost frames represent frames that are not correctly received or processed within a bandwidth allocation gap (BAG); a virtual link creation module configured to: create a virtual link for the lost frames; a fragmentation determination module configured to: determine whether to perform fragmentation processing on the lost frames based on the estimated transmission time T of the lost frames and the round-trip time RTT between the sending end and the receiving end, where the estimated transmission time T includes the time period from the time when the lost frames are marked to the time when it is estimated that the receiving end receives the lost frames; a fragmentation processing module configured to: in the case where it is determined that fragmentation processing is required for the lost frames, cut the lost frames into a specific number of fragments; a transmission module configured to: transmit the specific number of fragments to the receiving end through the virtual link; and a recovery module configured to: recover the lost frames according to the fragments received by the receiving end.

[0017] In some embodiments, the system further includes a frame retransmission scheduling module configured to: determine the priority of lost frames based on the chronological order of the times when the lost frames are marked; and schedule the retransmission of lost frames according to the priority.

[0018] In some embodiments, the fragmentation determination module is further configured to: if T < RTT, determine that fragmentation processing is not required for the lost frames; and if T ≥ RTT, determine that fragmentation processing is required for the lost frames.

[0019] In some embodiments, the transmission module is further configured to: in the case where it is determined that fragmentation processing is not required for the lost frames, retransmit the lost frames to the receiving end through the virtual link.

[0020] In some embodiments, the transmission module is further configured to: determine whether any of the specific number of fragments is lost during transmission based on the frame headers of each of all the fragments received by the receiving end, where the frame header of each fragment includes the frame sequence number of the frame to which the fragment belongs, the total number of fragments, and the fragment sequence number; if any fragment is lost, perform fragmentation processing on the lost fragment to obtain sub-fragments; and retransmit the sub-fragments to the receiving end until the receiving end receives the specific number of fragments.

[0021] In some embodiments, the recovery module is further configured to: sort all received fragments according to the total number of fragments, frame sequence number, and fragment sequence number included in the frame header of the fragments received by the receiving end; and group the sorted fragments to recover the lost frame.

[0022] In some embodiments, the virtual link creation module is further configured to: create a new UDP address and a new communication port for the sender and the receiver, and keep the MAC address and IP address of the sender and the receiver unchanged.

[0023] In some embodiments, each fragment in a specific number of fragments occupies a new UDP address and a new communication port, and the corresponding UDP address and communication port are released after the receiving end receives the fragment.

[0024] The present invention also provides a computer-readable medium storing a computer program for recovering lost frames in an airborne network. The computer program can be executed by a processor to perform the aforementioned method for recovering lost frames in an airborne network.

[0025] The technical solution of the present invention time-marks the lost frames to record the time when they are discarded, and uses the order of discarded time to schedule the retransmission of the lost frames, so that the receiving end can receive the lost frames in time within the BAG without affecting the transmission of data frames before and after the BAG. In addition, by performing fragment judgment and fragment transmission on the lost frames, it can ensure that the receiving end receives 100% of all data frames sent by the sending end, thereby ensuring the reliability and efficiency of data transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The features, nature and advantages of the present invention will become more apparent when the detailed description set forth below is understood in conjunction with the accompanying drawings. In the accompanying drawings, the same reference numerals are always used for corresponding identification. It should be noted that the drawings described are only schematic and non-limiting. In the drawings, the sizes of some components may be exaggerated and are not drawn to scale for illustrative purposes.

[0027] Figure 1 A schematic architecture diagram of the present invention for recovering lost frames in an airborne network is shown.

[0028] Figure 2 The method of the present invention for recovering lost frames in an airborne network is shown.

[0029] Figure 3 A schematic diagram showing the retransmission scheduling according to the marking time of the lost frame according to the present invention.

[0030] Figure 4 A schematic diagram of the fragment retransmission mechanism of the present invention is shown.

[0031] Figure 5 A system block diagram of the present invention for recovering lost frames in an airborne network is shown.

[0032] Figure 6 A block diagram of an apparatus including a system for recovering lost frames in an airborne network according to the present invention is shown. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. In the following detailed description, many specific details are set forth to provide a thorough understanding of the described exemplary embodiments. However, it is obvious to those skilled in the art that the described embodiments can be practiced without some or all of these specific details. In other exemplary embodiments, well-known structures are not described in detail to avoid unnecessarily obscuring the concepts of the present disclosure. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. At the same time, in the absence of conflict, the various aspects described in the embodiments can be combined arbitrarily.

[0034] Figure 1 A schematic architecture diagram 100 of the present invention for recovering lost frames in an airborne network is shown.

[0035] The redundancy management system on the aircraft will perform redundancy management and integrity checks on the transmission in the airborne network. For data frames transmitted from the sender to the receiver in the airborne network, the redundancy management system on the aircraft will read the frames within the specified bandwidth allocation gap (BAG) according to the aircraft's A and B networks. Frames that are not correctly received or processed due to network congestion or configuration errors are "discarded" by the redundancy management system. Such discarded frames are also referred to as "lost frames" or "discarded frames" in this article.

[0036] In the present invention, the transmitting end and receiving end in the airborne network are relative concepts. Any device / module with a transmitting and receiving function in the aircraft can be operated as a transmitting end or a receiving end. For example, a device E on the aircraft sends a data frame to another device F in a first time period, then device E is a transmitting end and device F is a receiving end. In another time period, device F sends a data frame to device E, then device E is a receiving end and device F is a transmitting end.

[0037] For frames lost between the transmitter and the receiver, the frames may first be time-stamped to record the time when the frame was discarded by the redundancy management system. At the same time, the lost frames may also be stored in the cache. The above operations may be performed by a corresponding system / module (e.g., a frame cache injection time-stamping system). The purpose of time-stamping the lost frames is to schedule the retransmission of the lost frames according to the time priority when rescheduling the retransmission of the lost frames. For example, in the case of multiple lost frames, the retransmission of these lost frames may be scheduled according to the time stamps of the respective lost frames.

[0038] After time stamping, a virtual link can be created for the lost frame. For a specific lost frame, a new UDP address and a new communication port can be created for the sender and receiver of the lost frame, while the MAC and IP addresses of the sender and receiver remain unchanged.

[0039] Then, it can be determined whether the lost frame needs to be fragmented.

[0040] The RTT (Round-Trip Time) of the sender and the receiver represents the total time from when the sender sends a data frame until the receiver returns an ACK message. In this article, RTT is also called the handshake retransmission time.

[0041] In airborne network communications, when a sender sends a data frame to a receiver and does not receive an ACK message from the receiver within the RTT, if a lost frame is scheduled and sent at this time, the new data frame cannot be retransmitted.

[0042] If the lost frame can be transmitted within the RTT of the sender and the receiver, it means that the lost frame can be transmitted within the handshake retransmission time (without triggering the scheduling of new data frames). At this time, it can be determined that there is no need to fragment the lost frame. In this case, the lost frame can be directly retransmitted to the receiver according to the priority of the time stamp.

[0043] If the lost frame cannot be transmitted within the RTT of the sender and the receiver, it means that the lost frame cannot be transmitted within the handshake retransmission time (because scheduling new data frames will cause the lost frame to be unable to be retransmitted, and the receiver will give priority to receiving new data frames). At this time, it can be determined that the lost frame needs to be fragmented. In such cases, the lost frame can be fragmented and transmitted. Specifically, the lost frame can be cut into multiple fragments, and a corresponding virtual link is created for each fragment, and the fragment is transmitted to the receiver through the virtual link. Through fragmentation processing and fragmentation transmission, the data transmission speed can be accelerated and the reliability of data transmission can be improved.

[0044] When the receiver receives the fragments, it can repack the fragments to restore the lost frames.

[0045] If the receiver receives all fragments (no fragments are lost), the receiver can successfully recover the lost frame.

[0046] If the receiving end does not receive all the fragments (a fragment is lost), the receiving end may send a negative acknowledgement (NACK) message of the lost fragment to the sending end, so that the sending end can retransmit the lost fragment.

[0047] When retransmitting lost fragments, the lost fragments may be fragmented again to improve the success rate of fragment transmission.

[0048] In addition, the scheduler can schedule the retransmission of lost frames and the transmission / retransmission of fragments. For example, the scheduler can create a new UDP address and a new communication port for the sender and receiver of the lost frame according to the time stamp of the lost frame. In the case of fragment loss, the scheduler can schedule the retransmission of the lost fragment.

[0049] By time-stamping the lost frames, it is possible to ensure that the receiving end can receive the data frames sent by the sending end within the BAG without affecting the data frames before and after the BAG, thereby improving the efficiency of data transmission. By fragmenting and transmitting / retransmitting the lost frames, it is possible to ensure that the receiving end receives all the data frames sent by the sending end, thereby improving the reliability of data transmission.

[0050] Figure 2 A method 200 of the present invention for recovering from lost frames in an onboard network is shown.

[0051] like Figure 2 As shown, the method 200 starts at step 205. At step 205, time-stamping is performed on lost frames between a transmitting end and a receiving end in the airborne network, where the lost frames represent frames that are not correctly received or processed in the BAG.

[0052] As mentioned above, due to network congestion or configuration errors, the redundant management system may "discard" data frames in the airborne network.

[0053] BAG represents the minimum time interval between the start positions of two adjacent frames in the same link without jitter. In an aircraft network, ideally, it is expected to transmit a data frame within each BAG to enable traffic control while providing continuous real-time flight data.

[0054] If the frames transmitted in the BAG on the A and B networks are not aligned (for example, due to jitter or delay), it is possible that the frames transmitted in the same BAG on the A and B networks cannot be read by the redundant management system at the same time. For example, it is possible that the redundant management system can read the data frames in a specific BAG on the A network, but fails to read the data frames in the same BAG on the B network. In this case, the redundant management system will discard the data frames on the B network. However, the lost frames often contain important data on the aircraft (for example, flight attitude information such as pressure altitude and pitch angle), and should not be "discarded" by the redundant management system at will.

[0055] In addition, in some cases, there may be no data frame in a certain BAG, which may result in a lack of continuity in the data provided to the pilot, increasing flight risks.

[0056] In various embodiments of the present invention, the frame buffer injection time-stamping system can time-stamp the lost frame to record the time when it is discarded. By using the time-stamping of the lost frame, scheduling can be performed according to the priority of the time-stamping when retransmitting the lost frame / segment, so that the receiving end can ensure that the data frame sent by the sending end is received in time within the BAG. The details of retransmission scheduling based on the marking time of the lost frame will be described below in conjunction with Figure 3 Further explanation is provided and will not be repeated here.

[0057] At step 210, a virtual link is created for the lost frame.

[0058] In various embodiments of the present invention, creating a virtual link may include: creating a new UDP address and a new communication port for the sender and receiver of the lost frame, and keeping the MAC address and IP address of the sender and receiver unchanged.

[0059] In conventional lost frame recovery schemes, lost frames are usually resent on the original link. However, this approach is prone to link congestion, so that the receiving end cannot receive the lost frames in time (for example, within the current BAG).

[0060] In contrast, by creating a new UDP address and a new communication port, link congestion can be avoided and the retransmission success rate can be improved.

[0061] In step 215, it is determined whether the lost frame needs to be fragmented based on the estimated transmission time T of the lost frame and the round-trip time RTT between the sender and the receiver, and the estimated transmission time T includes a time period from the time when the lost frame is marked to the time when the lost frame is expected to be received by the receiver. Specifically, the estimated transmission time T includes a first time period from the time when the lost frame is marked to the time when the sender sends the lost frame and a second time period from the time when the sender sends the lost frame to the time when the receiver is expected to receive the lost frame.

[0062] As described above, RTT represents the total time elapsed from when a data frame is sent from the sender until an acknowledgment (ACK) message is returned from the receiver, and is also referred to as the handshake retransmission time in this article.

[0063] If T < RTT, it means that the lost frame can be transmitted within the handshake retransmission time between the sender and the receiver. In this case, it can be determined that there is no need to fragment the lost frame. In this situation, the entire lost frame can be retransmitted to the receiver through the virtual link.

[0064] If T ≥ RTT, it means that the lost frame cannot be transmitted within the handshake retransmission time between the sender and the receiver. In this case, it can be determined that the lost frame needs to be fragmented to improve the transmission speed of the lost frame and reduce the expected transmission time of the lost frame to be less than the handshake retransmission time.

[0065] In practice, the RTT between a specific sender and a specific receiver is relatively fixed. Thus, the RTT between all senders and all receivers in the airborne network can be calculated and stored in advance. When making the judgment in step 215, the stored RTT of the sender and the receiver can be directly called to compare with T without calculating the RTT. In this way, the speed of determining whether to perform fragmentation processing can be accelerated, thereby improving the retransmission efficiency.

[0066] In some embodiments, to improve the success rate of lost frame retransmission, a certain amount of redundancy can also be incorporated when making the fragmentation judgment. For example, if T is less than RTT but the difference between them is not large (for example, the difference ΔT between them is less than a certain preset threshold), it can be considered that the expected transmission time of the lost frame is close to the handshake retransmission time and it may not be possible to complete the actual transmission of the lost frame within the handshake retransmission time. In this case, it can be determined that the lost frame needs to be fragmented to further improve the retransmission success rate.

[0067] In step 220, when it is determined that the lost frame needs to be fragmented, the lost frame is cut into a specific number of fragments.

[0068] In some embodiments, the number of fragments can be determined according to the number of failures. For example, when the receiver fails to receive the lost frame for the first time, the lost frame (for example, the valid frame of the lost frame) can be cut into 2 fragments, and then these 2 fragments are transmitted to the receiver on the virtual link. When the receiver fails to successfully receive these 2 fragments (the second failure), the lost frame can be cut into 4 fragments, and then these 4 fragments are transmitted to the receiver on the virtual link. The shorter the fragment length, the greater the probability of successful reception and the faster the data transmission speed. In other words, in such embodiments, the lost frame can be cut into 2 k ^k^ fragments, where k represents the number of failures.

[0069] In some other embodiments, the number of fragments can be determined according to the size of T and RTT. For example, if T is much larger than RTT (for example, T=6RTT), the lost frame can be cut into 8 fragments (instead of 2 fragments) during the first fragmentation, and these fragments can be transmitted to the receiving end on the virtual link. In this way, the number of fragments can be made more reasonable, thereby improving the success rate of the initial transmission of the fragments. If the initial transmission of the fragment fails, the number of fragments can be further increased and transmitted again.

[0070] In the above embodiment, when a segment transmission fails in a segment transmission (for example, the receiving end fails to receive one or more segments), all the segments of this transmission may be retransmitted, or only the failed segments may be retransmitted, thereby reducing bandwidth occupancy. In actual implementation, those skilled in the art may adopt a suitable retransmission strategy according to actual conditions.

[0071] In addition, in the case of fragmentation of lost frames, each fragment occupies a new UDP address and a new communication port, and the corresponding UDP address and communication port are released after the receiving end receives the fragment. In other words, in the case of fragmentation, a corresponding virtual link is created for each fragment.

[0072] By releasing the corresponding UDP address and communication port after receiving the fragment, the UDP address and communication port can be used for virtual link creation of other lost frames, thereby improving resource utilization and data transmission efficiency.

[0073] In step 225, a specific number of slices are transmitted to a receiving end via a virtual link.

[0074] During the fragment transmission process, it can be determined whether a fragment is lost (for example, a fragment is not received or a fragment is not received on time within a specified time).

[0075] Specifically, whether any fragment in a specific number of fragments is lost during transmission can be determined based on the frame header of each fragment among all the fragments received by the receiving end, where the frame header of each fragment includes the frame sequence number of the frame to which the fragment belongs, the total number of fragments, and the fragment sequence number.

[0076] For example, the frame header of the fragment can be marked in the form of Sum_N_T1_SN, where Sum represents the total number of fragments, N represents the sequence number of the fragment, T1 represents the time when the frame to which the fragment belongs is discarded, and SN represents the frame sequence number of the frame to which the fragment belongs.

[0077] After receiving the fragments, the receiver will first parse the MAC, IP, and UDP addresses, then identify the frame sequence number in the frame header, and then determine the order of each fragment based on the N before the frame sequence number.

[0078] Assume that Sum=3, and the receiving end has only received fragments N=1 and N=3, which means that fragment N=2 is lost.

[0079] If a fragment is lost, the lost fragment can be retransmitted until the receiving end receives all the fragments. The fragment retransmission mechanism will be discussed in detail below. Figure 4 A detailed description is given and will not be repeated here.

[0080] In step 230, the lost frames are restored according to the fragments received by the receiving end.

[0081] Specifically, all received fragments may be sorted according to the total number of fragments, frame sequence number, and fragment sequence number included in the frame header of the fragments received by the receiving end, and the sorted fragments may be packaged to restore the lost frame.

[0082] Data frames are generally sorted according to the frame sequence number, and the frame sequence number is in an increasing form. However, for lost frames, the size of the frame sequence number cannot reflect the time when the lost frame was discarded. This may cause the frames discarded earlier to be retransmitted later, so that it cannot be guaranteed that the receiving end can receive the retransmitted lost frames within the current BAG. In view of this, the present invention proposes to time-mark the lost frames and schedule retransmission according to the marking time of the lost frames to ensure that the receiving end receives the lost frames within the current BAG.

[0083] Figure 3 A schematic diagram 300 is shown of the present invention for performing retransmission scheduling according to the marking time of the lost frame.

[0084] For ease of explanation, assume that the redundancy management system discards a total of three frames: lost frame A, lost frame B, and lost frame C.

[0085] For each lost frame, a time stamp may be added to record the time when the lost frame is discarded. As an example, assume that the time (stamp time) when the lost frame A is discarded is T A , the time when the lost frame B is discarded is T B , and the time when the lost frame C is discarded is T C .

[0086] Afterwards, the order of the marking times of the lost frames can be determined. As an example but not a limitation, assume that T B Earlier than T A Earlier than T C In other words, among the three lost frames, lost frame B is discarded first, lost frame A is discarded next, and lost frame C is discarded last.

[0087] Next, the priority of each lost frame may be determined according to the order of the marking time, and the retransmission of each lost frame may be scheduled according to the priority.

[0088] In order to enable the receiving end to receive the lost frames in time within the BAG, the earliest lost frame should be retransmitted first. Thus, the earliest lost frame (lost frame B) can be given the highest priority, while the latest lost frame (lost frame C) can be given the lowest priority.

[0089] exist Figure 3 , the priority of lost frame B is determined / assigned as priority 1 (highest priority), the priority of lost frame C is determined / assigned as priority 3 (lowest priority), and the priority of lost frame A is determined / assigned as priority 2 (middle priority).

[0090] After determining the priority of each lost frame, retransmission of each lost frame may be scheduled according to the priority.

[0091] Specifically, in Figure 3 In the example, since the priority of lost frame B is the highest, the retransmission of lost frame B is scheduled first. When retransmitting lost frame B, it can be further determined whether to perform fragment processing and fragment transmission on lost frame B, such as Figure 3 As shown in the dotted box in . If it is determined that the lost frame B does not need to be fragmented and transmitted, the entire lost frame B is directly retransmitted to the receiving end on the created virtual link. If it is determined that the lost frame needs to be fragmented and transmitted, the lost frame B is cut into multiple fragments and the fragments are transmitted to the receiving end.

[0092] After the retransmission of lost frame B is completed, lost frame A has the highest priority among the remaining lost frames (lost frame A and lost frame C), so lost frame A can be scheduled for retransmission. Similarly, when retransmitting lost frame A, it can be further determined whether to perform fragment processing and fragment transmission on lost frame A.

[0093] After completing the retransmission of lost frame A, the retransmission of lost frame C can be scheduled. In other words, since lost frame C has the lowest priority, it can be scheduled last. Similarly, when retransmitting lost frame C, it can be further determined whether to perform fragment processing and fragment transmission on lost frame C.

[0094] In a specific implementation, if the number of lost frames to be retransmitted is large, when the lost frames need to be fragmented, the number of fragments may be increased to further increase the transmission speed of the lost frames and avoid affecting the retransmission of subsequent lost frames.

[0095] Figure 4 A schematic diagram 400 of a fragment retransmission mechanism of the present invention is shown.

[0096] As mentioned above, when performing segment transmission, if a segment is lost, the lost segment can be retransmitted. For the sake of explanation, it is assumed that there is a lost frame and the sender determines that the lost frame needs to be segmented.

[0097] like Figure 4 As shown in , during the first fragmentation, the sender cuts the lost frame into three fragments: fragment 1, fragment 2, and fragment 3.

[0098] Then, the sender may transmit the three fragments to the receiver. For example, the sender may create three virtual links for the three fragments and transmit the three fragments through the corresponding virtual links.

[0099] The receiving end may determine whether a fragment is lost based on the frame header of the received fragment. As an example, assume that the receiving end does not receive fragment 2. Therefore, the receiving end may send a NACK for fragment 2 to the transmitting end.

[0100] After receiving the NACK, the sender can determine that fragment 2 is lost and retransmit the lost fragment.

[0101] In a preferred implementation, the sending end may further fragment the lost fragment (fragment 2) ("second fragmentation" in the figure).

[0102] As an example, in Figure 4 In the example, the second fragmentation divides fragment 2 into two sub-fragments: sub-fragment 21 and sub-fragment 22. Subsequently, the sender can transmit the two sub-fragments to the receiver. For example, the sender can create two virtual links for the two sub-fragments and transmit the two sub-fragments through the corresponding virtual links.

[0103] After the receiving end successfully receives sub-segment 21 and sub-segment 22, the receiving end can restore segment 2 based on the two sub-segments. Thus, the receiving end receives all three segments.

[0104] After receiving all the fragments, the receiver recovers the lost frame based on these fragments.

[0105] It should be noted that Figure 4 The fragment retransmission mechanism shown in is only exemplary and not restrictive. In actual implementation, those skilled in the art may implement fragment retransmission in different ways. For example, if sub-fragments are still lost after the second fragmentation, those skilled in the art may also perform a third fragmentation until the receiving end receives all fragments and associated sub-fragments. In addition, Figure 4It is shown that the lost frame is cut into three slices and the lost slice is cut into two sub-slices, but those skilled in the art can also cut the lost frame into different numbers of slices and cut the lost slice into different numbers of sub-slices according to actual conditions.

[0106] Figure 5 A block diagram of a system 500 for recovering from lost frames in an airborne network according to the present invention is shown.

[0107] In some implementations, the system 500 may be installed in a device with transceiver functions on an aircraft, wherein the device may operate as a transmitter or a receiver. In other implementations, the system 500 may also be installed in other devices that control transmission between a transmitter and a receiver.

[0108] See also Figure 5 The system 500 may include a time stamp module 502, a virtual link creation module 504, a fragmentation determination module 506, a fragmentation processing module 508, a transmission module 510, a recovery module 512, and an optional frame retransmission scheduling module 514. Each of these modules may be directly or indirectly connected or communicated with each other on one or more buses 516. When the device in which the system 500 is installed operates as a transmitting end or a receiving end, the recovery module 512 in the above modules may operate when the device operates as a receiving end, and the other modules may operate when the device operates as a transmitting end.

[0109] In various embodiments of the present invention, the time marking module 502 is configured to: time mark lost frames between a transmitter and a receiver in an airborne network, where lost frames represent frames that are not correctly received or processed in a BAG.

[0110] In various embodiments of the present invention, the virtual link creation module 504 is configured to create a virtual link for the lost frame.

[0111] In some embodiments, the virtual link creation module 504 is further configured to: create a new UDP address and a new communication port for the sender and the receiver, and keep the MAC address and IP address of the sender and the receiver unchanged.

[0112] In various embodiments of the present invention, the fragmentation judgment module 506 is configured to determine whether it is necessary to fragment the lost frame based on the expected transmission time T of the lost frame and the round-trip time RTT between the sender and the receiver, and the expected transmission time T includes the time period from the time when the lost frame is marked to the time when the lost frame is expected to be received by the receiver.

[0113] In some embodiments, the fragmentation determination module 506 is further configured to: if T < RTT, determine that there is no need to perform fragmentation processing on the lost frame; and if T ≥ RTT, determine that fragmentation processing on the lost frame is required.

[0114] In various embodiments of the present invention, the fragmentation processing module 508 is configured to: in the case where it is determined that fragmentation processing on the lost frame is required, cut the lost frame into a specific number of fragments.

[0115] In various embodiments of the present invention, the transmission module 510 is configured to: transmit a specific number of fragments to the receiving end through a virtual link.

[0116] In some embodiments, the transmission module 510 is further configured to: in the case where it is determined that there is no need to perform fragmentation processing on the lost frame, retransmit the lost frame to the receiving end through a virtual link.

[0117] In some embodiments, the transmission module 510 is further configured to: determine whether any of the specific number of fragments is lost during transmission based on the frame headers of each of all the fragments received by the receiving end, where the frame header of each fragment includes the frame sequence number of the frame to which the fragment belongs, the total number of fragments, and the fragment sequence number; if any fragment is lost, perform fragmentation processing on the lost fragment to obtain sub - fragments; and retransmit the sub - fragments to the receiving end until the receiving end receives a specific number of fragments.

[0118] In various embodiments of the present invention, the restoration module 512 may be configured to: restore the lost frame according to the fragments received by the receiving end.

[0119] In some embodiments, the restoration module 512 is further configured to: sort all the received fragments according to the total number of fragments, frame sequence number, and fragment sequence number included in the frame headers of the fragments received by the receiving end; and packetize the sorted fragments to restore the lost frame.

[0120] In various embodiments of the present invention, the frame retransmission scheduling module 514 is configured to: determine the priority of the lost frames based on the chronological order of the times when the lost frames are marked; and schedule the retransmission of the lost frames according to the priority.

[0121] In specific practice, the above modules of system 500 can all be implemented in the form of configuration files. For example, each of these modules can be configured as a configuration file in the end system of each device of the aircraft and the switch of the AFDX network. In this way, the function of the corresponding module can be implemented by calling the configuration file (for example, by the operating system and processing unit of each end system), thereby realizing the recovery of lost frames. In this way, the technical solution of the present invention can be implemented without adding additional equipment, and the existing equipment and its interface settings on the aircraft are not affected. At the same time, the corresponding module can be updated or upgraded by changing the configuration file, which is easy to implement.

[0122] Although Figure 5 Specific modules of system 500 are shown in FIG. 5 , but it should be understood that these modules are exemplary and non-restrictive. In different implementations, one or more of these modules may be combined, split, removed, or additional modules may be added. For example, in some implementations, the slicing determination module 506 and the slicing processing module 508 may be combined into a single module. In some implementations, system 500 may also include additional modules.

[0123] Figure 6 A block diagram of a device 600 including a system for recovering lost frames in an airborne network according to the present invention is shown. The device 600 may be a transmitter, a receiver, or other devices controlling transmission between a transmitter and a receiver in the airborne network.

[0124] The apparatus illustrates a general hardware environment in which the present invention may be applied according to its exemplary embodiments.

[0125] Now refer to Figure 6 Device 600 is described, which is an exemplary embodiment of a hardware device that can be applied to various aspects of the present invention. Device 600 can be any machine configured to perform processing and / or computing, and can be, but is not limited to, a workstation, a server, a desktop computer, a laptop computer, a tablet computer, a personal digital assistant (PDA), a smart phone, or any combination thereof. The above system can be implemented in whole or in part by device 600 or similar devices or systems.

[0126] The device 600 may include components that may be connected or in communication with the bus 612 via one or more interfaces. For example, the device 600 may include the bus 612, a processor 602, a memory 604, an input device 708, and an output device 610, among other things.

[0127] Processor 602 may be any type of processor and may include, but is not limited to, a general purpose processor and / or a dedicated processor (e.g., a special processing chip), an intelligent hardware device (e.g., a general purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, processor 602 may be configured to operate a memory array using a memory controller. In other cases, a memory controller (not shown) may be integrated into processor 602. Processor 602 may be responsible for managing the bus and general processing, including executing software stored on memory. Processor 602 may also be configured to perform various functions described herein related to recovering lost frames in an onboard network. For example, the processor 602 may be configured to: time-mark lost frames between a transmitter and a receiver in an airborne network, where a lost frame indicates a frame that is not correctly received or processed within a bandwidth allocation interval (BAG); create a virtual link for the lost frame; determine whether the lost frame needs to be fragmented based on an estimated transmission time T of the lost frame and a round-trip time RTT between the transmitter and the receiver, where the estimated transmission time T includes a time period from the time when the lost frame is marked to the time when the lost frame is expected to be received by the receiver; if it is determined that the lost frame needs to be fragmented, cut the lost frame into a specific number of fragments; transmit the specific number of fragments to the receiver via the virtual link; and restore the lost frame based on the fragments received by the receiver.

[0128] The memory 604 may be any storage device that enables data storage. The memory 604 may include, but is not limited to, a disk drive, an optical storage device, a solid-state memory, a floppy disk, a hard disk, a magnetic tape or any other magnetic medium, an optical disk or any other optical medium, a ROM (read-only memory), a RAM (random access memory), a cache memory, and / or any other memory chip or cartridge, and / or any other medium from which a computer can read data, instructions, and / or code. The memory 604 may store computer executable software 606 including computer readable instructions that, when executed, cause the processor to perform various functions described herein related to recovery of lost frames in an airborne network.

[0129] Input device 608 may be any type of device that can be used to input information.

[0130] Output device 610 may be any type of device for outputting information. In one embodiment, output device 1010 may be any type of output device that can display information.

[0131] The technical solution of the present invention effectively improves the reliability and efficiency of data frames in airborne network transmission. The time stamp of lost frames ensures the priority of retransmission scheduling, and the fragmented transmission and retransmission mechanism further optimizes bandwidth utilization and significantly improves the overall performance of data transmission. The technical solution of the present invention can prevent the loss of onboard data and reduce the flight risk caused by the loss of important data on the aircraft.

[0132] The detailed description described above in conjunction with the accompanying drawings describes examples and does not represent all examples that can be implemented or fall within the scope of the claims. The terms "example" and "exemplary" when used in this specification mean "used as an example, instance or illustration" and do not mean "better or better than other examples".

[0133] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, use of these phrases may refer to more than just one embodiment. Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0134] The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the universal principles defined herein may be applied to other aspects. Therefore, the claims are not intended to be limited to the aspects shown herein, but should be granted the full scope consistent with the claims in language, wherein the singular reference to the elements is not intended to mean "there is and only one", but "one or more", unless otherwise specifically stated. Unless otherwise specifically stated, the term "some" refers to one or more. The elements of the various aspects described throughout the present invention are all structurally and functionally equivalent schemes currently or hereafter known to those of ordinary skill in the art and are expressly incorporated herein by reference, and are intended to be covered by the claims.

[0135] It should also be noted that these embodiments may be described as a process depicted as a flow chart, flow diagram, structure diagram, or block diagram. Although the flow chart may describe the operations as sequential processes, many of these operations can be performed in parallel or concurrently. In addition, the order of these operations can be rearranged.

[0136] Although various embodiments have been illustrated and described, it should be understood that the embodiments are not limited to the precise configuration and components described above. Various modifications, substitutions and improvements obvious to those skilled in the art may be made in the arrangement, operation and details of the devices disclosed herein without departing from the scope of the claims.

Claims

1. A method for recovering lost frames in an airborne network, comprising: Time-stamping the lost frames between a sending end and a receiving end in the airborne network, where the lost frames represent frames that are not correctly received or processed within a bandwidth allocation gap (BAG); Creating a virtual link for the lost frames; Determining whether to fragment the lost frames based on the estimated transmission time T of the lost frames and the round-trip time RTT between the sending end and the receiving end, where the estimated transmission time T includes the time period from the time when the lost frames are marked to the time when it is estimated that the receiving end receives the lost frames; In the case where it is determined that the lost frames need to be fragmented, cutting the lost frames into a specific number of fragments; Transmitting the specific number of fragments to the receiving end through the virtual link; and Recovering the lost frames according to the fragments received by the receiving end.

2. The method according to claim 1, characterized in that Further comprising: Determining the priority of the lost frames based on the chronological order of the time when the lost frames are marked; And Scheduling the retransmission of the lost frames according to the priority.

3. The method according to claim 1, characterized in that Determining whether to fragment the lost frames based on the estimated transmission time T of the lost frames and the round-trip time RTT between the sending end and the receiving end further comprises: If T < RTT, determining that there is no need to fragment the lost frames; and If T ≥ RTT, determining that the lost frames need to be fragmented.

4. The method according to claim 1, characterized in that: Further comprising: In the case where it is determined that there is no need to fragment the lost frames, retransmitting the lost frames to the receiving end through the virtual link.

5. The method according to claim 1, characterized in that Further comprising: Based on the frame headers of each of all the fragments received by the receiving end, determining whether any of the fragments in the specific number of fragments are lost during transmission, where the frame header of each fragment includes the frame sequence number of the frame to which the fragment belongs, the total number of fragments, and the fragment sequence number; If there are lost fragments, fragmenting the lost fragments to obtain sub-fragments; And Retransmitting the sub-fragments to the receiving end until the receiving end receives the specific number of fragments.

6. The method according to claim 5, characterized in that Further comprising: Sorting all the received fragments according to the total number of fragments, frame sequence number, and fragment sequence number included in the frame headers of the fragments received by the receiving end; And Packetizing the sorted fragments to recover the lost frames.

7. The method according to claim 1, characterized in that Creating a virtual link for the lost frames further comprises: Creating new UDP addresses and new communication ports for the sending end and the receiving end, and keeping the MAC addresses and IP addresses of the sending end and the receiving end unchanged.

8. The method according to claim 7, characterized in that Each of the specific number of fragments occupies a new UDP address and a new communication port, and the corresponding UDP address and communication port are released after the receiving end receives the fragment.

9. A system for recovering lost frames in an airborne network, comprising: A time-stamping module configured to: time-stamp the lost frames between a sending end and a receiving end in the airborne network, where the lost frames represent frames that are not correctly received or processed within a bandwidth allocation gap (BAG); A virtual link creation module, which is configured to: create a virtual link for the lost frame; A fragmentation determination module, which is configured to: determine whether fragmentation processing needs to be performed on the lost frame based on the estimated transmission time T of the lost frame and the round-trip time RTT between the sending end and the receiving end, where the estimated transmission time T includes the time period from the time when the lost frame is marked to the time when it is estimated that the receiving end receives the lost frame; A fragmentation processing module, which is configured to: cut the lost frame into a specific number of fragments in the case where it is determined that fragmentation processing needs to be performed on the lost frame; A transmission module, which is configured to: transmit the specific number of fragments to the receiving end through the virtual link; And A restoration module, which is configured to: restore the lost frame according to the fragments received by the receiving end.

10. The system according to claim 9, characterized in that Further includes a frame retransmission scheduling module, which is configured to: Determine the priority of the lost frame based on the chronological order of the time when the lost frame is marked; and Schedule the retransmission of the lost frame according to the priority.

11. The system according to claim 9, characterized in that The fragmentation determination module is further configured to: If T < RTT, determine that fragmentation processing does not need to be performed on the lost frame; and If T ≥ RTT, determine that fragmentation processing needs to be performed on the lost frame.

12. The system according to claim 9, characterized in that The transmission module is further configured to: In the case where it is determined that fragmentation processing does not need to be performed on the lost frame, retransmit the lost frame to the receiving end through the virtual link.

13. The system according to claim 9, characterized in that The transmission module is further configured to: Determine whether any of the specific number of fragments is lost during transmission based on the frame header of each of all the fragments received by the receiving end, and the frame header of each fragment includes the frame sequence number of the frame to which the fragment belongs, the total number of fragments, and the fragment sequence number; If there are lost fragments, perform fragmentation processing on the lost fragments to obtain sub-fragments; And Retransmit the sub-fragments to the receiving end until the receiving end receives the specific number of fragments.

14. The system according to claim 13, characterized in that The restoration module is further configured to: Sort all the received fragments according to the total number of fragments, frame sequence number, and fragment sequence number included in the frame header of the fragments received by the receiving end; and Packetize the sorted fragments to restore the lost frame.

15. The system according to claim 9, characterized in that The virtual link creation module is further configured to: create a new UDP address and a new communication port for the sending end and the receiving end, and keep the MAC address and IP address of the sending end and the receiving end unchanged.

16. The system according to claim 15, characterized in that Each of the specific number of fragments occupies a new UDP address and a new communication port, and the corresponding UDP address and communication port are released after the receiving end receives the fragment.

17. A computer-readable medium that stores a computer program for restoring lost frames in an airborne network, and the computer program can be executed by a processor to perform the method according to any one of claims 1-8.

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