CN111404649A - A Beidou message feedback and retransmission method and system supporting multiple senders - Google Patents

Abstract

The invention relates to a Beidou message feedback and retransmission method and system supporting multiple senders, and belongs to the field of Beidou communication. The system includes: a prediction analysis module, installed at the message receiving end, connected to the Beidou message sending and receiving equipment, used to collect relevant data required for analysis, and establish a message frequency prediction model; a feedback control module, installed at the message receiving end, based on the results of the prediction analysis module Perform real-time message status judgment and provide the feedback receipt to the message sender; the historical message storage module, installed on the message sender, is connected to the Beidou message sending and receiving device to store the historical messages that have been sent, which is convenient for query and retransmission; receipt message processing The module, installed on the message sender, is used to process the packet loss receipt message, determine and resend the message. The invention greatly reduces the number of return receipt messages, reduces the difficulty of processing the return receipt messages by the sending end, and achieves the purpose of performing parallel feedback on monitoring messages of multiple sending ends.

Description

A Beidou message feedback and retransmission method and system supporting multiple senders

technical field

The invention belongs to the field of Beidou communication, and relates to a communication method and system in which a message receiver determines, feeds back and retransmits Beidou messages that are not successfully sent by a plurality of message senders.

Background technique

The Beidou satellite system provides short message communication services. The equipment connected to the satellite positioning terminal can use the satellite signal for two-way information transmission through the Beidou satellite and the Beidou ground service station. At present, the short message communication function is widely used in many aspects such as emergency rescue emergency communication, geological monitoring information transmission and so on. Due to the limitation of Beidou communication capacity and frequency, in current monitoring applications, multiple short messages are usually spliced into long messages and periodic message transmission is used to improve the Beidou communication capability.

Although short message communication is a major feature of the Beidou satellite system, due to various factors such as weather, obstacles, and clutter, the reliability of Beidou communication is low, and the packet loss rate of messages is about 5% to 25%. The prior art solution improves the reliability of Beidou message transmission through methods such as error correction coding of redundant messages, receipt feedback and retransmission mechanism at the message receiving end (such as patent applications with application numbers of 201610038674X, 201610296794X, 201711132710X, or 2017111031473). Once the message receiver successfully receives the Beidou message, it will send a receipt to the message sender. The message sender determines whether the message is successfully sent by receiving the receipt message. Although the existing message feedback and retransmission mechanism can improve the success rate of Beidou message communication to a certain extent, it has the following shortcomings:

① It is difficult to apply Beidou message transmission for one-to-many communication. Due to the limitation of the underlying mechanism of Beidou communication, the transmission frequency used by the message receiver is the same as that of the sender. When the message receiver receives BeiDou messages from multiple senders at the same time, it cannot send receipts to messages from multiple senders according to the receiving frequency.

②Receipt feedback is required for all successfully received messages, and both parties need to confirm the receipt message repeatedly, which increases the amount of messages in the channel and increases the complexity of round-trip message processing in the communication system. At the same time, as the volume of Beidou communication messages increases, in order to avoid satellite channel congestion, the transmission suppression function of Beidou satellites will further reduce the communication success rate.

③It may cause unnecessary retransmission of Beidou messages. If the acknowledgement for the successful reception of the marked message is lost, the sender may make a wrong judgment on the message sending status, send the received message repeatedly, and occupy the communication channel.

In view of the above deficiencies, a new Beidou message feedback and retransmission method is urgently needed. For the application of multiple different Beidou senders sending messages at a fixed frequency, it solves the problem of too large transmission volume of the successful receipt of the message. The failure judgment and feedback start, reduce the amount of receipt messages sent, reduce the complexity of the system's message processing process, and do not affect the retransmission of lost messages.

SUMMARY OF THE INVENTION

In view of this, the purpose of the present invention is to provide a Beidou message feedback and retransmission method and system that supports multiple senders. The message reception time interval determines the message delay status. By returning the message failure receipt to the sender instead of the successful receipt, the number of receipt messages is greatly reduced, and the difficulty of processing the receipt message by the sender is reduced, so as to achieve parallel feedback of monitoring messages from multiple receivers. Purpose.

To achieve the above object, the present invention provides the following technical solutions:

1. A Beidou message feedback and retransmission method supporting multiple senders, which specifically includes the following steps:

S1: Predictive analysis: collect relevant data required for analysis, and establish a message frequency prediction model;

S2: Feedback control: Real-time message status judgment based on the prediction analysis result and feedback receipt to the message sender;

S3: Store historical messages: store the sent historical messages;

S4: Process the receipt message: Process the packet loss receipt message, determine and resend the message.

Further, it is characterized in that the step S1 specifically includes:

S11: Collecting data: For each message sender _j , receive and collect n historical messages from the Beidou messaging device. The main collected information is the Beidou time Ti in the message, and the receiving time interval _ti between two adjacent messages. 1≤i≤n, etc.;

S12: Establish a prediction model: For each message sender j, select the latest n consecutive historical message interval data, and establish a prediction model for the next message interval:

t _i =f(t _i-1 , t _i-2 , t _i-3 ...t _in ) (1)

Solve the model based on methods such as least squares or matrix estimation, and use residual autocorrelation coefficients to test the model;

S13: Prediction time interval: Calculate the next message interval t _i+1 based on the prediction model of formula (1) and the collected historical interval time data;

S14: Decision coefficient selection: select the abnormal message interval decision coefficient α _i ∈ [1, 2) according to the state of the communication channel of different senders; this coefficient is used to amplify the prediction time α _i t _i+1 to avoid unnecessary message repetition pass.

Further, it is characterized in that the step S2 specifically includes:

S21: Waiting for a message: Obtain the waiting time α _i t _i+1 from the prediction model, and wait for the next Beidou message; if the Beidou message is not received within α _i t _i+1 , it is considered that there is a potential packet loss event, and enter the Step S22; if the message is received, enter step S23;

S22: message timeout feedback: check whether a timeout receipt has been sent during the previous waiting period; if it occurs, record the sending time of the previous timeout receipt as _xi ; if it does not occur, record the previous message reception time as _xi ; according to the sender The number j sends a message reception failure receipt to the message sender, and the content of the receipt includes: the time _xi when the previous message should be received, the current time _{xi +1} , and the time Ti when the previous message was sent. Record the current message sending time x _i+1 , and return to step S21 to continue predicting and waiting;

S23: message reception feedback: check the latest received message sending time T _i+1 and whether a timeout receipt was sent during the last waiting period; if it happens, and T _i+1 is before the last time-out receipt message sending time _xi , send the message to The sender of number j continues to send a message overtime receipt, and the content of the receipt includes: the time xi that the previous message should be received, the current time _{xi +1} , the sending time T _i+1 of the previous message, and the recording time xi ₊ 1 of the receipt message sending; In other cases, the message reception is considered successful, the message data is processed, the latest message reception time x _i+1 and the message sending time T _i+1 are recorded, and no receipt is sent; return to step S21 to continue predicting and waiting.

Further, it is characterized in that the step S3 specifically includes: storing a message after sending a message to the Beidou message receiving end, and the content of the stored message includes: the Beidou time _yi and other data that need to be stored, etc. when the message is sent, and the storage amount does not exceed k pieces .

Further, it is characterized in that the step S4 specifically includes:

S41: Receipt data reception: read the Beidou receipt message from the Beidou message sending and receiving device, including the terminal device number j, the previous message should receive the time _xi , the current time _{xi +1} , the previous message sending time Ti, etc.;

S42: Search for retransmitted messages: according to the receipt message sent by the receiving end; look up the message that needs to be retransmitted from the historical message repository, and the retransmitted message needs to meet the following conditions: the message sending time is after the sending time of the last received message y _i >T _i ; at the same time, when the message is sent, _xi ≤y _i ≤x _i+1 within the time interval when the message is not received;

S43: Message retransmission: For each piece of data that is successfully searched, determine the necessity of retransmission. If retransmission is required, it will be retransmitted to the receiving end through the Beidou transceiver; if the data or the importance of the data is not found in the storage queue If it is lower, it will not be retransmitted.

2. A Beidou message feedback and retransmission system that supports multiple senders. As shown in Figure 1, the system includes four parts: a prediction analysis module, a feedback control module, a historical message storage module and a receipt message processing module. The Beidou message sender sends monitoring messages to the receiver at an approximate fixed frequency according to the frequency limit of the Beidou communication card. The Beidou message receiver can simultaneously receive and analyze Beidou data from multiple different senders.

The prediction analysis module is installed at the message receiving end, connected to the Beidou message sending and receiving equipment, and used for collecting relevant data required for analysis and establishing a message frequency prediction model;

The feedback control module is installed at the message receiving end, performs real-time message status judgment based on the results of the predictive analysis module, and provides the feedback receipt to the message sending end;

The historical message storage module is installed at the message sending end, connected to the Beidou message sending and receiving equipment, and used to store the sent historical messages, which is convenient for query and retransmission;

The receipt message processing module is installed at the message sending end, and is used for processing the packet loss receipt message, and determining and resending the message.

The beneficial effects of the present invention are:

1) In the present invention, through the evaluation of the received timeout message, the Beidou message receiver can actively send the failure receipt instead of successfully receiving the receipt, which can reduce the number of receipt messages that need to be transmitted and processed in the channel, reduce the complexity of the system processing message flow, and at the same time. Does not affect retransmission of lost messages.

2) Due to the reduction in the number of receipts to be sent, the present invention enables one receiver to feed back messages from multiple senders at the same time, provides reliability guarantee for multiple Beidou transmission links, and is more suitable for monitoring application scenarios.

Other advantages, objects, and features of the present invention will be set forth in the description that follows, and will be apparent to those skilled in the art based on a study of the following, to the extent that is taught in the practice of the present invention. The objectives and other advantages of the present invention may be realized and attained by the following description.

Description of drawings

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be preferably described in detail below with reference to the accompanying drawings, wherein:

1 is a frame diagram of the Beidou message feedback and retransmission system according to the present invention;

Fig. 2 is the schematic flow chart that the message receiving end executes;

FIG. 3 is a schematic flowchart of the execution of the message sending end.

Detailed ways

The embodiments of the present invention are described below through specific specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the drawings provided in the following embodiments are only used to illustrate the basic idea of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

An embodiment is preferred in the present invention, and the implementation of the technical solution is described from two aspects of a message receiving end and a message sending end. The civilian card is used in the Beidou transceiver terminal, and the transmission frequency does not exceed times/60 seconds.

The execution flow of the message receiving end is shown in Figure 2.

1) The predictive analysis module collects the messages sent by the sender in advance, and the main collected information includes: the Beidou time T _i in the message, the receiving time interval t _i of two adjacent messages, and the sending terminal device number j, etc. Each sender normally receives message time interval data not less than 100 pieces (1≤i≤100).

将相邻的每50条t_i数据列为一组t _s，构建不少于50组t_s序列数据。例如t_s1＝{t₁，t₂，…，t₅₀}，t_s2＝{t₂，t₃，…，t₅₁}，…，。将50组数据及其后续数据代入预测模型中，通过最小二乘法或矩阵求解等方法求解参数

2) For each sender j, the prediction analysis module establishes the message time prediction model of the sender based on the historical interval data t _i as follows:

Each 50 adjacent pieces of ti data are listed as a group of t _s to construct no less than 50 groups of _{t s sequence} data. For example, t _s1 = {t ₁ , t ₂ , . . . , t ₅₀ }, t _s2 = {t ₂ , t ₃ , . . . , t ₅₁ }, . Substitute 50 sets of data and their subsequent data into the prediction model, and solve the parameters by methods such as least squares or matrix solution

选择某判定系数阈值如α_i＝1.5。3) For each sender j, the prediction analysis module predicts the interval time of the next message

Select a certain determination coefficient threshold such as α _i =1.5.

4) The feedback control module obtains the prediction time and the determination coefficient from the prediction analysis module, and starts to wait for the reception of the message in a loop.

5) In the real-time message receiving process, for each sender j, if the message waiting time exceeds 1.5t _i+1 and no message is received, it is determined that the message is lost. Check whether there is a timeout in the last waiting period 1.5t _i+1 , and if so, record the time _xi when the previous timeout receipt was sent, the current time _{xi +1} , and the time Ti when the previous message was sent. If it does not exist, record the previous message receiving time _xi , the current time _xi+1 , and the previous message sending time T _i . Go to step 8).

6) If the Beidou message sending and receiving device receives the message within the message waiting period, the feedback control module reads the sending terminal device number j, and the Beidou time Ti ₊₁ and the receiving time _xi+1 are included in the message.

7) For the corresponding sender j, check whether the timeout event was sent during the previous waiting period. If it occurs and T _i+1 ≤ the previous time-out receipt sending time _xi , record the previous time-out receipt sending time _xi , the current time _xi+1 , and the previous message sending time T _i+1 , and perform step 8). In other cases, it is determined that the message is received normally, and step 9) is executed.

8) According to the recorded time interval and the last message sending time, transmit a receipt failure acknowledgement message to the sender j. The receipt message includes: the start time x _i of the time interval in which the message was not received, the end time x _i+1 , and the sending time Ti or Ti _{+ 1} of the previous received message.

9) Parse the possibly received messages, and at the same time, the loop flow returns to step 3) to wait for re-prediction.

The execution flow of the message sender is shown in Figure 3.

1) The historical message storage module of each sender j stores the latest Beidou messages sent, and the storage amount does not exceed 10. The storage content includes: the Beidou time _yi and original information of the message sent. If more than 10 historical Beidou messages are stored, the stored messages will be overwritten and updated using the principle of first-in, first-out.

2) The receipt message processing module of each sender j receives the Beidou message from the Beidou message sending and receiving device, and if a certain message is a receipt message, it reads the receipt message data, including the terminal device number j, and the time interval in which the message is not received starts. Time _xi , end time _xi+1 , sending time T _i of the previous received message, etc.

3) The receipt message processing module searches for the messages that have been sent but not received from the 10 stored historical messages. The searched message satisfies that the sending time is after the sending time of the previous received message y _i >T _i , and the sending time is within the time interval when no message is received, _xi ≤y _i ≤x _i+1 . Historical messages that meet the above conditions are eligible for resending.

4) The message that needs to be resent is taken out from the historical message store, and the necessity of retransmission of each found message is checked. If retransmission is required, it is resent to the message receiver, otherwise the receipt message is discarded and no further processing is performed. Messages lost during transmission are retransmitted only once.

5) Send data normally and continuously update the coverage history message repository.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be Modifications or equivalent replacements, without departing from the spirit and scope of the technical solution, should all be included in the scope of the claims of the present invention.

Claims (6)

1. A Beidou message feedback and retransmission method supporting multiple sending ends is characterized by comprising the following steps:

s1: and (3) prediction analysis: collecting relevant data required by analysis, and establishing a message frequency prediction model;

s2: feedback control: performing real-time message state judgment based on the prediction analysis result and feeding back a receipt to a message sending end;

s3: storing the history message: storing the transmitted history message;

s4: and (4) processing the receipt message: and processing the packet loss receipt message, and judging and retransmitting the message.

2. The method according to claim 1, wherein the step S1 specifically includes:

s11: collecting data: aiming at each message sending end j, n historical messages are received and collected from Beidou message transmitting and receiving equipment, and the collected information is self-contained information in the messagesBig dipper time T_iTwo adjacent message reception intervals t_i，1≤i≤n；

S12: establishing a prediction model: aiming at each message sending end j, selecting the latest continuous n pieces of historical message interval data, and establishing a prediction model of the next message interval time:

t_i＝f(t_i-1，t_i-2，t_i-3...t_i-n) (1)

solving the model based on a least square method or a matrix estimation method and the like, and carrying out model test by adopting a residual autocorrelation coefficient and the like;

s13: the prediction time interval is as follows: calculating the next message interval t based on the prediction model of equation (1) and the collected historical interval time data_i+1；

S14 decision coefficient selection, selecting abnormal message interval decision coefficient α according to the state of different sender side communication channels_i∈ [1, 2) ] that amplifies the prediction time α_it_i+1。

3. The method according to claim 2, wherein the step S2 specifically includes:

s21 waiting for message obtaining wait time α from prediction model_it_i+1Wait for the next Beidou message, if α_it_i+1If the Beidou message is not received within the time, a potential packet loss event is considered to occur, and the step S22 is carried out; if the message is received, go to step S23;

s22: message timeout feedback: checking whether the previous waiting period sends a timeout receipt; if so, recording the sending time of the previous overtime receipt as x_i(ii) a If not, recording the receiving time of the previous message as x_i(ii) a And sending a message receiving failure receipt to the message sending end according to the sending end number j, wherein the receipt content comprises: the moment x when the previous message should be received_iCurrent time x_i+1The previous message sending time T_i(ii) a Recording the current message sending time x_i+1Returning to step S21 to continue prediction waiting;

s23: message reception feedback: checking the latest received message transmission time T_i+1And whether the timeout receipt is sent during the last waiting period; if so, and T_i+1At the last timeout receipt message sending time x_iBefore, the sender of the number j continues to send the message overtime receipt, and the receipt content includes: the moment x when the previous message should be received_iCurrent time x_i+1The previous message sending time T_i+1Recording the sending time x of receipt message_i+1(ii) a For other cases, the message is considered to be successfully received, the message data is processed, and the latest message receiving time x is recorded_i+1Time of message transmission T_i+1No receipt is sent; returning to step S21 continues prediction waiting.

4. The method according to claim 3, wherein the step S3 specifically includes: the Beidou information receiving terminal sends information and then stores the information, and the stored information content comprises the following steps: beidou time y for message sending_iAnd other data needing to be stored, and the storage capacity does not exceed k.

5. The method according to claim 4, wherein the step S4 specifically includes:

s41: receipt data reception: reading Beidou receipt message from Beidou message transceiver equipment, wherein the Beidou receipt message comprises a terminal equipment number j, and the previous message is received at a time x_iCurrent time x_i+1The previous message sending time T_i；

S42: searching for retransmission messages: according to the receipt message sent by the receiving end; searching a message needing to be retransmitted from a historical message storage library, wherein the retransmitted message needs to meet the following conditions: the message sending time being y after the last received message sending time_i>T_i(ii) a At the same time, the message sending time is x in the time interval of not receiving the message_i≤y_i≤x_i+1；

S43: and (3) message retransmission: judging the retransmission necessity of each piece of successfully searched data, and if the retransmission is needed, retransmitting the data to a receiving end through the Beidou transmitting and receiving equipment; if the data is not found in the store queue or is of low importance, no retransmission is performed.

6. A Beidou message feedback and retransmission system supporting multiple sending ends is characterized by comprising a prediction analysis module, a feedback control module, a historical message storage module and a receipt message processing module;

the prediction analysis module is arranged at a message receiving end, connected with the Beidou message transceiving equipment and used for acquiring relevant data required by analysis and establishing a message frequency prediction model;

the feedback control module is arranged at the message receiving end, performs real-time message state judgment based on the result of the prediction analysis module and provides a feedback receipt for the message sending end;

the history message storage module is arranged at the message sending end, connected with the Beidou message receiving and sending equipment and used for storing the sent history messages and facilitating query and retransmission;

and the receipt message processing module is arranged at the message sending end and used for processing the packet loss receipt message, judging and resending the message.

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