CN115515259B - A method and device for reporting MSD via RTCP - Google Patents

Abstract

Translated fromChinese

本发明公开了一种通过RTCP上报MSD的方法，包括如下步骤。步骤S1：在APP类型的RTCP包中增加6种子类型。步骤S2：在eCall建立后，IVS向PSAP发送RTCP同步包；PSAP收到RTCP同步包后，向IVS回复RTCP确认包；IVS收到RTCP确认包后，计算RTCP同步包和RTCP确认包在网络传输的往返时间RTT，并向PSAP回复携带RTT的RTCP告知收到确认包。步骤S31：在eCall通话过程中，IVS向PSAP发送RTCP MSD数据包，其中携带有MSD数据；如果PSAP顺利地收到了RTCP MSD数据包，则向IVS回复RTCP告知收到MSD数据包；当IVS在重传时间后仍未收到RTCP告知收到MSD数据包，IVS向PSAP重新发送RTCP MSD数据包，其中携带有MSD数据；重传时间与RTT成正比。本发明根据往返时间成正比地设置重传时间，提升了丢包重传效率。

The present invention discloses a method for reporting MSD through RTCP, comprising the following steps. Step S1: adding 6 subtypes to the RTCP packet of APP type. Step S2: after the eCall is established, the IVS sends an RTCP synchronization packet to the PSAP; after the PSAP receives the RTCP synchronization packet, it replies with an RTCP confirmation packet to the IVS; after the IVS receives the RTCP confirmation packet, it calculates the round-trip time RTT of the RTCP synchronization packet and the RTCP confirmation packet in the network transmission, and replies with an RTCP notification receipt packet carrying the RTT to the PSAP. Step S31: during the eCall call process, the IVS sends an RTCP MSD data packet to the PSAP, which carries MSD data; if the PSAP successfully receives the RTCP MSD data packet, it replies with an RTCP notification receipt of the MSD data packet to the IVS; when the IVS still does not receive the RTCP notification receipt of the MSD data packet after the retransmission time, the IVS resends the RTCP MSD data packet to the PSAP, which carries the MSD data; the retransmission time is proportional to the RTT. The present invention sets the retransmission time in direct proportion to the round-trip time, thereby improving the efficiency of packet loss retransmission.

Description

Method and device for reporting MSD through RTCP

Technical Field

The invention relates to a method for transmitting data information by an on-board system through RTCP (RTP Control Protocol, real-time transport control protocol).

Background

With the development of wireless communication technology, more and more vehicles have wireless communication capability in emergency situations. For example, when a traffic accident occurs In the vehicle, the IVS (In-VEHICLE SYSTEM ) may automatically call the PSAP (Public SAFETY ANSWERING Point) by means of an emergency call (EMERGENCY CALL, eCall) to make the driver or passenger timely contact with the PSAP, and the IVS may also send the MSD (Minimum Set of Data, minimum data set) to the PSAP. The MSD may contain a vehicle identification number, vehicle location information, number of people on the vehicle, current time stamp, and other information related thereto.

The rapid and accurate reporting of the MSD (i.e., the IVS sends the MSD information to the PSAP) is critical to the rescue of the vehicle. The chinese patent application CN102362476a, CN104580218a, discloses a method for transmitting MSD using RTCP protocol, wherein negotiation of MSD transmission mode (e.g. whether RTCP transmission is used), timeout retransmission of RTCP, etc. are described. It is mentioned that the predetermined time T2 is used as the timeout retransmission time, but it is not explained how the T2 value is decided.

Various types (types) of RTCP packets (packets) are defined in the internet standard (INTERNET STANDARD) RFC 3550, including specifically SR type (type=200), RR type (type=201), SDES type (type=202), BYE type (type=203), APP type (type=204). The first four protocol types belong to the RFC 3550 standard definition, and APP types can be defined by different application programs. The RFC 3550 standard allows applications to define their own subtype (subtype) and thus define new RTCP packets.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a method for timely and reliably transmitting MSD (MSD over RTCP) through an RTCP protocol, which can accurately realize timeout retransmission.

In order to solve the technical problems, the invention discloses a method for reporting MSD through RTCP, which comprises the following steps. Step S1, adding 6 seed types, namely RTCP synchronous packets, into real-time transmission control protocol (RTCP) packets of an APP type, wherein the RTCP synchronous packets are used for handshake of an IVS of a vehicle-mounted system to a Public Safety Answering Point (PSAP), and a local time field is arranged for recording the current time point of the IVS when the IVS sends the RTCP synchronous packets. The system comprises a PSAP, an RTCP acknowledgement packet, a remote time field and a delay time field, wherein the PSAP is used for sending a response to the IVS after receiving the RTCP synchronous packet, the remote time field is used for recording the content of a local time field in the RTCP synchronous packet received by the PSAP, and the delay time field is used for recording the time delayed by the PSAP between the time of receiving the RTCP synchronous packet and the time of sending the RTCP acknowledgement packet. The RTCP notification reception confirmation packet is used for notifying the PSAP of reception after the IVS receives the RTCP confirmation packet, and a round trip time field is arranged in the RTCP notification reception confirmation packet and is used for recording the calculated round trip time of the RTCP synchronization packet and the RTCP confirmation packet transmitted in the network after the IVS receives the RTCP confirmation packet. -an MSD request packet for the PSAP to request the IVS to send the minimum data set MSD. The RTCP MSD data packet is used for the IVS to send MSD data to the PSAP, wherein the MSD data field is set for recording the MSD data sent by the IVS to the PSAP. -RTCP tells receipt of the MSD packet for the PSAP to tell the IVS that it has received after receipt of the MSD data. Step S2, after the emergency call eCall is established, the IVS sends an RTCP synchronous packet to the PSAP, the PSAP replies an RTCP confirmation packet to the IVS after receiving the RTCP synchronous packet, the IVS calculates round trip time RTT of the RTCP synchronous packet and the RTCP confirmation packet transmitted in the network after receiving the RTCP confirmation packet, and replies an RTCP notification received confirmation packet carrying the RTT to the PSAP. Step S31, in the eCall process, the IVS sends an RTCP MSD data packet to the PSAP, wherein the RTCP MSD data packet carries MSD data, if the PSAP successfully receives the RTCP MSD data packet, the IVS replies an RTCP notification to the IVS that the MSD data packet is received, when the IVS still does not receive the RTCP notification to the IVS after the retransmission time, the IVS retransmits the RTCP MSD data packet to the PSAP, wherein the RTCP MSD data packet carries MSD data, and the retransmission time is in direct proportion to RTT.

Further, the local time field, the remote time field, the delay time field or the absolute time of the record or the relative time of the record, wherein the lengths of the local time field, the remote time field and the delay time field are all 2 bytes, and if the time required to be recorded is represented by binary system and exceeds 2 bytes, only the lower 16 bits are taken to be recorded in the corresponding fields.

Further, in the step S2, the method of calculating RTT by the IVS is rtt=time_cur-time_last-time_delay, time_cur represents the current time, time_last represents the content of the remote time field in the RTCP acknowledgement packet, that is, the time when the IVS last transmitted the RTCP synchronization packet, and time_delay represents the content of the delay time field in the RTCP acknowledgement packet.

Further, in the step S3, if the maximum retransmission number is reached, the IVS does not receive the RTCP sent by the PSAP to inform the received MSD packet, and then the IVS tries to retransmit the RTCP MSD packet once every fixed time until the IVS receives the RTCP sent by the PSAP to inform the received MSD packet, where the fixed time is far longer than the retransmission time.

Further, in the step S31, if the IVS receives the MSD request packet sent from the PSAP, the IVS stops attempting to retransmit the RTCP MSD packet every fixed time, and immediately responds to the MSD request packet to send the RTCP MSD packet to the PSAP.

Further, in the step S31, if the MSD data of the IVS is updated, the IVS stops attempting to retransmit the RTCP MSD packet every fixed time.

Alternatively, step S31 is replaced with step S32. Step S32, in the eCall process, the PSAP actively transmits an MSD request packet to the IVS to request for obtaining MSD data, the IVS transmits an RTCP MSD data packet to the PSAP after receiving the MSD request packet, wherein the MSD data packet carries the MSD data, if the PSAP successfully receives the RTCP MSD data packet, the PSAP replies the RTCP to the IVS to inform that the MSD data packet is received, when the PSAP still does not receive the RTCP MSD data packet after the retransmission time, the PSAP retransmits the MSD request packet to the IVS to request for obtaining the MSD data, and the retransmission time is in direct proportion to RTT.

Further, in the step S32, if the maximum retransmission times are reached, the PSAP still does not receive the RTCP MSD packet sent by the IVS, and then the PSAP tries to retransmit the MSD request packet every fixed time until the PSAP receives the RTCP MSD packet sent by the IVS, where the fixed time is far longer than the retransmission time.

The invention also discloses a device for reporting the MSD through the RTCP, which comprises an added subtype unit, a synchronous handshake unit and a push data unit. The adding subtype unit is used for adding 6 seed types in real-time transmission control protocol (RTCP) packets of an APP type, and the added seed types are respectively an RTCP synchronous packet used for handshake of an IVS of a vehicle-mounted system to a Public Safety Answering Point (PSAP), an RTCP acknowledgement packet used for sending a response to the IVS after the PSAP receives the RTCP synchronous packet, an RTCP notification receipt acknowledgement packet used for sending the RTCP acknowledgement packet to the PSAP after the IVS receives the RTCP acknowledgement packet, an MSD request packet used for the PSAP to request the IVS to send a minimum data set (MSD), an RTCP MSD data packet used for the IVS to send MSD data to the PSAP, and an RTCP notification received MSD data packet used for sending acknowledgement information to the IVS after the PSAP receives the MSD data. And a local time field is arranged in the RTCP synchronous packet and is used for recording the current time point of the IVS when the IVS sends the RTCP synchronous packet. The RTCP acknowledgement packet is provided with a remote time field and a delay time field, wherein the remote time field is used for recording the content of a local time field in an RTCP synchronous packet received by the PSAP, and the delay time field is used for recording the time delayed between the time when the PSAP receives the RTCP synchronous packet and the time when the RTCP acknowledgement packet is sent. The RTCP notification receiving confirmation packet is provided with a round trip time field which is used for recording the calculated round trip time of the RTCP synchronous packet and the RTCP confirmation packet in the network transmission after the RTCP confirmation packet is received by the IVS. And the RTCP MSD data packet is provided with an MSD data field used for recording MSD data sent by the IVS to the PSAP. The synchronization handshake unit is used for sending an RTCP synchronization packet to the PSAP by the IVS after the emergency call eCall is established, replying an RTCP confirmation packet to the IVS after the RTCP synchronization packet is received by the PSAP, calculating round trip time RTT of the RTCP synchronization packet and the RTCP confirmation packet transmitted by the network after the RTCP confirmation packet is received by the IVS, and replying an RTCP notification received confirmation packet carrying the RTT to the PSAP. The push data unit is used for sending an RTCP MSD data packet to the PSAP by the IVS in the eCall process, wherein the RTCP MSD data packet carries MSD data, replying an RTCP to the IVS to inform that the MSD data packet is received if the RTCP MSD data packet is successfully received by the PSAP, informing that the MSD data packet is received when the RTCP is not received by the IVS after the retransmission time, and retransmitting the RTCP MSD data packet to the PSAP by the IVS, wherein the RTCP MSD data packet carries MSD data, and the retransmission time is in direct proportion to RTT.

Alternatively, the push data unit is replaced with the pull data unit. The pulling data unit is used for actively sending an MSD request packet to the IVS by the PSAP in the eCall process to request to acquire MSD data, sending an RTCP MSD data packet to the PSAP by the IVS after the MSD request packet is received, wherein the MSD data packet carries the MSD data, replying an RTCP to the IVS to inform that the MSD data packet is received if the RTCP MSD data packet is successfully received by the PSAP, retransmitting the MSD request packet to the IVS by the PSAP when the RTCP MSD data packet is not received by the PSAP after retransmission time, and requesting to acquire the MSD data by the PSAP, wherein the retransmission time is in direct proportion to RTT.

The invention has the technical effects that (1) MSD data is carried by RTCP packets for sending, and the RTCP packets have no too much control data except MSD data and are light for receiving and sending. (2) The sending and receiving of RTCP packets does not affect RTP (Real timeTransport Protocol, real-time transport protocol) packets and does not affect voice transmission. (3) The reliability of the RTCP packet in network transmission is improved, and the sender can judge whether the MSD data is received by the receiver through the RTCP informing the MSD data packet. And (4) the packet loss retransmission efficiency is improved. The round trip time of the RTCP packet in the network is calculated through the handshake of RTCP (step S2), and the retransmission time is set in proportion to the round trip time, so that the timeout retransmission is efficiently performed.

Drawings

Fig. 1 is a flowchart of a first embodiment of a method for reporting an MSD via RTCP according to the present disclosure.

FIG. 2 is a schematic diagram of an exemplary data structure of a newly added RTCP synchronization packet in accordance with the present invention.

FIG. 3 is a schematic diagram of an exemplary data structure of a newly added RTCP acknowledgement packet according to the present invention.

FIG. 4 is a diagram of an exemplary data structure of an additional RTCP notification acknowledgement packet according to the present invention.

Fig. 5 is a schematic diagram of an exemplary data structure of a new MSD request packet in accordance with the present invention.

FIG. 6 is a schematic diagram of an exemplary data structure of a newly added RTCP MSD packet according to the present invention.

FIG. 7 is a diagram illustrating an exemplary data structure of an added RTCP notification received MSD packets according to the present invention.

Fig. 8 is a flowchart of a second embodiment of a method for reporting an MSD via RTCP.

Fig. 9 is a schematic structural diagram of a first embodiment of an apparatus for reporting MSD through RTCP according to the present invention.

Fig. 10 is a schematic structural diagram of a second embodiment of an apparatus for reporting MSD through RTCP according to the present disclosure.

Reference numerals in the figure illustrate that 1 is an add subtype unit, 2 is a synchronous handshake unit, 31 is a push data unit, and 32 is a pull data unit.

Detailed Description

Referring to fig. 1, a method for reporting MSD via RTCP according to an embodiment of the present invention includes the following steps.

Step S1, adding 6 seed types to the RTCP packet of the APP type (type=204), wherein the seed types are respectively an 'RTCP synchronous packet' (RTCP SYNC PACKET) used for the IVS to handshake to the PSAP, an 'RTCP acknowledgement packet' (RTCPconfirm packet) used for the PSAP to send a response to the IVS after receiving the RTCP synchronous packet, an 'RTCP notification receipt acknowledgement packet' (RTCP ack for confirm packet) used for the IVS to send the MSD after receiving the RTCP acknowledgement packet, an 'MSD request packet' (MSD request packet) used for the PSAP to request the IVS to send the MSD, an 'RTCP MSD data packet' (RTCP MSD DATA PACKET) used for the IVS to send the MSD data to the PSAP, and an 'RTCP notification MSD data packet' (RTCP ack for MSDDATA PACKET) used for the PSAP to send acknowledgement information to the IVS after receiving the MSD data. As an example, the subtype (subtype) fields of these 6 subtype RTCP packets have values of 0, 1, 2,3, 4, 5, respectively. These 6 sub-types of RTCP packets (or RTCP data frames) are essentially extensions within the framework of the RFC 3550 standard.

Referring to FIG. 2, an exemplary data structure of the newly added RTCP synchronization packet of the present invention is shown. The first row represents bytes (type) and the second row represents bits (bit). The subtype field in the third row has a value of, for example, 0, indicating that the RTCP packet is an RTCP sync packet. Some fields are defined in the RFC3550 standard, and the present invention is consistent with the RFC3550 standard and will not be described in detail. The invention adds a local time field in the RTCP synchronous packet to record the current time point of the IVS when the IVS sends the RTCP synchronous packet. The local time field may record absolute time, or may record relative time (e.g., time the device is powered on to the current time). Preferably, the local time field is 2 bytes in length, i.e., 16 bits, and ranges from 0 to 65535 in milliseconds. The field length of the current time recorded in the common network protocol is usually 4 bytes, and the local time field of 2 bytes is more space-saving. Typically, the current time of the IVS exceeds this range of values after being represented in binary form, and only the lower 16 bits (bits) of the binary form of the current time of the IVS are recorded in the local time field when the RTCP sync packet is constructed.

Referring to FIG. 3, an exemplary data structure of the newly added RTCP acknowledgement packet of the present invention is shown. The first row represents bytes and the second row represents bits. The subtype field in the third row has a value of, for example, 1, indicating that the RTCP packet is an RTCP acknowledgement packet. Some fields are defined in the RFC 3550 standard, and the present invention is consistent with the RFC 3550 standard and will not be described in detail. The present invention adds a remote time (remote time) field and a delay time (DELAY TIME) field to the RTCP acknowledgement packet. The remote time field is used to record the contents of the local time field within the RTCP sync packet received by the PSAP. The delay time field is used to record the time delayed by the PSAP between the receipt of the RTCP sync packet and the transmission of the RTCP acknowledgement packet. Preferably, the length of the remote time field is 2 bytes and the length of the delay time field is 2 bytes, all in milliseconds. The field length of the current time recorded in the common network protocol is usually 4 bytes, and the remote time field and the delay time field of 2 bytes are more space-saving.

Referring to FIG. 4, an exemplary data structure of the present invention for an additional RTCP notification acknowledgement packet is shown. The first row represents bytes and the second row represents bits. The subtype field in the third row has a value of, for example, 2, indicating that the RTCP packet is an RTCP notification receipt of an acknowledgement packet. Some fields are defined in the RFC 3550 standard, and the present invention is consistent with the RFC 3550 standard and will not be described in detail. The invention adds Round Trip Time (RTT) field in RTCP informing and receiving acknowledgement packet, which is used to record the calculated Round trip time of RTCP synchronous packet and RTCP acknowledgement packet transmitted by network after IVS receives RTCP acknowledgement packet, and this Round trip time is used in the following timeout retransmission mechanism.

Referring to fig. 5, an exemplary data structure for a new MSD request packet of the present invention is shown. The first row represents bytes and the second row represents bits. The subtype field in the third row has a value of, for example, 3, indicating that the RTCP packet is an MSD request packet. All fields are defined in the RFC 3550 standard, and the invention is consistent with the RFC 3550 standard and will not be described in detail. The present invention does not add a new field in the MSD request packet.

Referring to FIG. 6, an exemplary data structure of the newly added RTCP MSD packet of the present invention is shown. The first row represents bytes and the second row represents bits. The subtype field in the third row has a value of, for example, 4, indicating that the RTCP packet is an RTCP MSD packet. Some fields are defined in the RFC 3550 standard, and the present invention is consistent with the RFC 3550 standard and will not be described in detail. The present invention adds an MSD data (MSD data) field to the RTCP MSD packet to record the MSD data sent by the IVS to the PSAP, e.g., at the end of the RTCP MSD packet.

Referring to FIG. 7, an exemplary data structure of the present invention for an additional RTCP notification of the receipt of an MSD packet is shown. The first row represents bytes and the second row represents bits. The subtype field in the third row has a value of, for example, 5, indicating that the RTCP packet is RTCP to inform the receipt of the MSD packet. All fields are defined in the RFC 3550 standard, and the invention is consistent with the RFC 3550 standard and will not be described in detail. The invention informs the received MSD data packet of not adding new field in RTCP.

And step S2, after the eCall is established, the IVS sends an RTCP synchronization packet to the PSAP. After receiving the RTCP synchronization packet, the PSAP replies an RTCP acknowledgement packet to the IVS. After the IVS receives the RTCP acknowledgement packet, calculating the round trip time RTT of the RTCP synchronous packet and the RTCP acknowledgement packet transmitted by the network, and replying RTCP notification received acknowledgement packet carrying RTT to the PSAP. RTT is used for a subsequent timeout retransmission policy by the IVS or PSAP.

The method of calculating RTT is as follows. The IVS obtains the current time, noted as time_cur. The IVS obtains the content of the remote time field in the RTCP acknowledgement packet, i.e., the time the IVS last sent the RTCP sync packet, and marks it as time_last. The IVS obtains the content of the delay time field in the RTCP acknowledgement packet, denoted as time_delay. The calculation formula of RTT is rtt=time_cur-time_last-time_delay.

In step S31, in the eCall process, the IVS sends an RTCP MSD data packet to the PSAP, wherein the RTCP MSD data packet carries MSD data. If the PSAP receives the RTCP MSD data packet successfully, the IVS is replied with RTCP to inform that the MSD data packet is received. If the PSAP does not receive an RTCP MSD packet, e.g., an RTCP MSD packet is lost in the network, then the RTCP notification of receipt of the MSD packet is not sent to the IVS. When the IVS does not receive the RTCP after the retransmission time (timeout) and notifies the received MSD packet, the IVS retransmits (i.e., retransmits) the RTCP MSD packet, which carries the MSD data, to the PSAP. The retransmission time is typically set to 2 times RTT, or proportional. If the PSAP receives the retransmitted RTCP MSD data packet successfully, the RTCP is replied to the IVS to inform that the MSD data packet is received. The number of retransmissions is not limited. In general, it is preferable to multiplex a maximum of 3 times, plus a total of up to 4 times for the first transmission.

If the IVS does not receive RTCP from the PSAP to inform the MSD packet after the maximum number of retransmissions is reached, the transmission is considered to be failed, which indicates that the network condition is very poor. The later IVS attempts to retransmit the RTCP MSD packet every 5 seconds, and the RTCP MSD packet is transmitted every 5 seconds without taking up too much RTP bandwidth. After the network is restored, the MSD data can be sent out in time until the sending is successful (that is, the IVS informs that the MSD data packet is received after receiving the RTCP sent by the PSAP). But will terminate the above every 5 seconds attempt retransmission if there are 2 cases where (1) the IVS receives the MSD request packet from the PSAP. For example, immediately after the network recovers, the PSAP sends an MSD request packet. At this point, the IVS immediately responds to the MSD request packet by attempting retransmission every 5 seconds before stopping, and sends the RTCP MSD data packet to the PSAP. (2) The MSD data may be updated after a period of time, such as changes in vehicle information (vehicle position movement, vehicle angle change (rollover), temperature change in the vehicle (fire), etc.). If the MSD data of the IVS is updated, the previous attempt to retransmit every 5 seconds is stopped and the new MSD data is subsequently sent to the PSAP.

Referring to FIG. 8, a second embodiment of the method for reporting MSD over RTCP is disclosed. In the second embodiment, only the step S31 in the first embodiment is replaced with the step S32.

And step S32, in the eCall process, the PSAP actively transmits an MSD request packet to the IVS to request to acquire MSD data. After receiving the MSD request packet, the IVS sends an RTCP MSD data packet to the PSAP, wherein the RTCP MSD data packet carries MSD data. If the PSAP receives the RTCP MSD data packet successfully, the IVS is replied with RTCP to inform that the MSD data packet is received. If the PSAP does not receive an RTCP MSD packet, e.g., an MSD request packet is lost in the network, then the RTCP is not sent to the IVS informing of the receipt of the MSD packet. When the PSAP still does not receive the RTCP MSD data packet after the retransmission time, the PSAP retransmits (i.e., retransmits) the MSD request packet to the IVS, requesting acquisition of the MSD data. The retransmission time is typically chosen to be 2 times RTT, or proportional. After receiving the retransmitted MSD request packet, the IVS sends an RTCP MSD data packet to the PSAP, wherein the RTCP MSD data packet carries MSD data. If the PSAP receives the RTCP MSD data packet successfully, the IVS is replied with RTCP to inform that the MSD data packet is received. The number of retransmissions is not limited. In general, it is preferable to multiplex a maximum of 3 times, plus a total of up to 4 times for the first transmission.

If the PSAP does not receive the RTCP MSD data packet sent by the IVS after the maximum retransmission times are reached, the request transmission is considered to be failed, which indicates that the network condition is very bad at the moment. The PSAP then attempts to retransmit the MSD request packet every 5 seconds until the PSAP receives the RTCP MSD packet from the IVS.

Comparing the two embodiments, the first embodiment is that the IVS pushes (push) the MSD data to the PSAP, which includes a process of retransmitting the RTCP MSD packet in a specific scenario. The second embodiment is that the PSAP pulls (pull) MSD data from the IVS, which includes the process of retransmitting the MSD request packet in the specific scenario.

Referring to fig. 9, an embodiment of an apparatus for reporting MSD via RTCP according to the present invention includes an add subtype unit 1, a synchronization handshake unit 2, and a push data unit 31. The apparatus shown in fig. 9 corresponds to the method shown in fig. 1.

The adding subtype unit 1 is configured to add 6 seed types in an RTCP packet of an APP type, which are respectively a "RTCP synchronization packet" for handshake by the IVS to the PSAP, a "RTCP acknowledgement packet" for sending a response to the IVS after the PSAP receives the RTCP synchronization packet, a "RTCP notification receipt acknowledgement packet" for sending the PSAP after the IVS receives the RTCP acknowledgement packet, a "MSD request packet" for the PSAP to request the IVS to send the MSD, a "RTCP MSD data packet" for the IVS to send the MSD data to the PSAP, and a "RTCP notification receipt MSD data packet" for sending acknowledgement information to the IVS after the PSAP receives the MSD data.

And a local time field is arranged in the RTCP synchronous packet and is used for recording the current time point of the IVS when the IVS sends the RTCP synchronous packet.

The RTCP acknowledgement packet is provided with a remote time field and a delay time field. The remote time field is used to record the contents of the local time field within the RTCP sync packet received by the PSAP. The delay time field is used to record the time delayed by the PSAP between the receipt of the RTCP sync packet and the transmission of the RTCP acknowledgement packet.

The RTCP notification receiving confirmation packet is provided with a round trip time field which is used for recording the calculated round trip time of the RTCP synchronous packet and the RTCP confirmation packet in the network transmission after the RTCP confirmation packet is received by the IVS.

And the RTCP MSD data packet is provided with an MSD data field used for recording MSD data sent by the IVS to the PSAP.

The synchronization handshake unit 2 is configured to send an RTCP synchronization packet to the PSAP by the IVS after the eCall is established. After receiving the RTCP synchronization packet, the PSAP replies an RTCP acknowledgement packet to the IVS. After the IVS receives the RTCP acknowledgement packet, calculating the round trip time RTT of the RTCP synchronous packet and the RTCP acknowledgement packet transmitted by the network, and replying RTCP notification received acknowledgement packet carrying RTT to the PSAP.

The push data unit 31 is configured to send, during the eCall call, an RTCP MSD packet to the PSAP by the IVS, where the RTCP MSD packet carries MSD data. If the PSAP receives the RTCP MSD data packet successfully, the IVS is replied with RTCP to inform that the MSD data packet is received. When the IVS does not receive the RTCP after the retransmission time, the IVS informs that the MSD packet is received, and the IVS resends the RTCP MSD packet to the PSAP, where the RTCP MSD packet carries the MSD data. The retransmission time is proportional to RTT. Further, if the IVS does not receive the RTCP to inform the reception of the MSD packet after the maximum number of retransmissions is reached, the retransmission of the RTCP MSD packet is attempted every fixed time interval. The fixed time is much longer (greater than or equal to 10 times) than the retransmission time.

Referring to fig. 10, a second embodiment of the apparatus for reporting MSD via RTCP is disclosed. In the second embodiment, only the push data unit 31 in the first embodiment is replaced by the pull data unit 32. The apparatus shown in fig. 10 corresponds to the method shown in fig. 8.

The pull data unit 32 is configured to, during an eCall call, the PSAP actively sends an MSD request packet to the IVS to request for obtaining MSD data. After receiving the MSD request packet, the IVS sends an RTCP MSD data packet to the PSAP, wherein the RTCP MSD data packet carries MSD data. If the PSAP receives the RTCP MSD data packet successfully, the IVS is replied with RTCP to inform that the MSD data packet is received. When the PSAP still does not receive the RTCP MSD data packet after the retransmission time, the PSAP resends the MSD request packet to the IVS to request to acquire the MSD data. The retransmission time is proportional to RTT. Further, if the PSAP does not receive the RTCP MSD packet after the maximum number of retransmissions is reached, the MSD request packet is attempted to be retransmitted every fixed time interval until the PSAP receives the RTCP MSD packet. The fixed time is much longer than the retransmission time.

Compared with the prior art, the invention discloses a method for transmitting MSD data through an RTCP protocol and an RTCP packet, which comprises the steps of calculating the round trip time of the RTCP packet in a network, setting the round trip time of the time-out retransmission time to be 2 times, sending the time-out retransmission instance of the RTCP MSD data packet to a PSAP by an IVS, and sending the time-out retransmission instance of the MSD request packet to the IVS by the PSAP, so that the time-out retransmission can be timely and accurately realized. When retransmitting, firstly, the retransmission is carried out at a smaller time interval (namely retransmission time), and then the retransmission is carried out at a larger time interval (namely fixed time) after the maximum retransmission times are reached, so that normal RTP voice communication is not interfered, and successful retransmission can be realized in time after the network is recovered to be normal.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Various modifications and variations of the present invention will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (4)

Translated fromChinese

1.一种通过RTCP上报MSD的方法，其特征是，包括如下步骤；1. A method for reporting MSD via RTCP, comprising the following steps:步骤S1：在APP类型的实时传输控制协议RTCP包中增加6种子类型，分别是：Step S1: Add 6 subtypes to the APP type Real-time Transport Control Protocol RTCP packet, namely:——RTCP同步包，用于车载系统IVS向公共安全应答点PSAP握手；其中设置有本地时间字段，用来记录IVS发送RTCP同步包时IVS当前的时间点；-- RTCP synchronization packet, used by the vehicle system IVS to shake hands with the public safety answering point PSAP; a local time field is set in it to record the current time point of the IVS when the IVS sends the RTCP synchronization packet;——RTCP确认包，用于PSAP收到RTCP同步包后向IVS发送响应；其中设置有远程时间字段和延迟时间字段；远程时间字段用来记录PSAP收到的RTCP同步包里面的本地时间字段的内容；延迟时间字段用来记录PSAP在收到RTCP同步包后到发送RTCP确认包之间所延迟的时间；-- RTCP confirmation packet, used by PSAP to send a response to IVS after receiving the RTCP synchronization packet; it contains a remote time field and a delay time field; the remote time field is used to record the content of the local time field in the RTCP synchronization packet received by PSAP; the delay time field is used to record the delay between PSAP receiving the RTCP synchronization packet and sending the RTCP confirmation packet;——RTCP告知收到确认包，用于IVS收到RTCP确认包后向PSAP告知已收到；其中设置有往返时间字段，用来记录IVS在收到RTCP确认包后，计算出的RTCP同步包和RTCP确认包在网络传输的往返时间；--RTCP notification of receipt of confirmation packet, used by IVS to inform PSAP of receipt after receiving RTCP confirmation packet; a round-trip time field is set to record the round-trip time of RTCP synchronization packet and RTCP confirmation packet transmitted in the network calculated by IVS after receiving RTCP confirmation packet;——MSD请求包，用于PSAP请求IVS发送最小数据集MSD；——MSD request packet, used by PSAP to request IVS to send minimum data set MSD;——RTCP MSD数据包，用于IVS向PSAP发送MSD数据；其中设置有MSD数据字段，用来记录IVS向PSAP发送的MSD数据；--RTCP MSD data packet, used by IVS to send MSD data to PSAP; an MSD data field is provided to record the MSD data sent by IVS to PSAP;——RTCP告知收到MSD数据包，用于PSAP收到MSD数据后向IVS告知已收到；——RTCP notifies the receipt of MSD data packet, which is used by PSAP to inform IVS of the receipt after receiving MSD data;步骤S2：在紧急呼叫eCall建立后，IVS向PSAP发送RTCP同步包；PSAP收到RTCP同步包后，向IVS回复RTCP确认包；IVS收到RTCP确认包后，计算RTCP同步包和RTCP确认包在网络传输的往返时间RTT，并向PSAP回复携带RTT的RTCP告知收到确认包；RTT＝time_cur―time_last―time_delay；time_cur表示当前时间；time_last表示RTCP确认包中的远程时间字段的内容，也就是IVS上次发送RTCP同步包的时间；time_delay表示RTCP确认包中的延迟时间字段的内容；RTT用于IVS或PSAP后续的超时重传策略；Step S2: After the emergency call eCall is established, the IVS sends an RTCP synchronization packet to the PSAP; after receiving the RTCP synchronization packet, the PSAP replies with an RTCP confirmation packet to the IVS; after receiving the RTCP confirmation packet, the IVS calculates the round-trip time (RTT) between the RTCP synchronization packet and the RTCP confirmation packet in the network transmission, and replies with an RTCP packet carrying the RTT to inform the PSAP of the receipt of the confirmation packet; RTT = time_cur - time_last - time_delay; time_cur represents the current time; time_last represents the content of the remote time field in the RTCP confirmation packet, that is, the time when the IVS last sent the RTCP synchronization packet; time_delay represents the content of the delay time field in the RTCP confirmation packet; RTT is used for the subsequent timeout retransmission strategy of the IVS or PSAP;步骤S31：在eCall通话过程中，IVS向PSAP发送RTCP MSD数据包，其中携带有MSD数据；如果PSAP顺利地收到了RTCP MSD数据包，则向IVS回复RTCP告知收到MSD数据包；当IVS在重传时间后仍未收到RTCP告知收到MSD数据包，IVS向PSAP重新发送RTCP MSD数据包，其中携带有MSD数据；重传时间与RTT成正比；如果到达最大重传次数后，IVS还是没有收到PSAP发来的RTCP告知收到MSD数据包，后面IVS每隔固定时间尝试重传一次RTCP MSD数据包，直至IVS收到PSAP发来的RTCP告知收到MSD数据包为止；所述固定时间远大于所述重传时间；如果IVS的MSD数据有更新，则IVS停止每隔固定时间的重传尝试，改为发送新的MSD数据给PSAP；Step S31: During the eCall call, the IVS sends an RTCP MSD packet carrying MSD data to the PSAP; if the PSAP successfully receives the RTCP MSD packet, it replies to the IVS with an RTCP notification that the MSD packet has been received; when the IVS still does not receive the RTCP notification that the MSD packet has been received after the retransmission time, the IVS resends the RTCP MSD packet carrying MSD data to the PSAP; the retransmission time is proportional to the RTT; if the IVS still does not receive the RTCP notification that the MSD packet has been received from the PSAP after the maximum number of retransmissions, the IVS will attempt to retransmit the RTCP MSD packet at a fixed time interval until the IVS receives the RTCP notification that the MSD packet has been received from the PSAP; the fixed time is much longer than the retransmission time; if the MSD data of the IVS is updated, the IVS stops the retransmission attempt at the fixed time interval and sends new MSD data to the PSAP instead;或者，将步骤S31替换为步骤S32；Alternatively, step S31 is replaced by step S32;步骤S32：在eCall通话过程中，PSAP主动向IVS发送MSD请求包，请求获取MSD数据；IVS收到MSD请求包后，向PSAP发送RTCP MSD数据包，其中携带有MSD数据；如果PSAP顺利地收到了RTCP MSD数据包，则向IVS回复RTCP告知收到MSD数据包；当PSAP在重传时间后仍未收到RTCP MSD数据包，PSAP向IVS重新发送MSD请求包，请求获取MSD数据；重传时间与RTT成正比；如果到达最大重传次数后，PSAP还是没有收到IVS发来的RTCP MSD数据包，后面PSAP每隔固定时间尝试重传一次MSD请求包，直至PSAP收到IVS发来的RTCP MSD数据包为止；所述固定时间远大于所述重传时间。Step S32: During the eCall call, the PSAP proactively sends an MSD request packet to the IVS, requesting to obtain MSD data; after receiving the MSD request packet, the IVS sends an RTCP MSD data packet carrying the MSD data to the PSAP; if the PSAP successfully receives the RTCP MSD data packet, it replies RTCP to the IVS to inform it of the receipt of the MSD data packet; when the PSAP still does not receive the RTCP MSD data packet after the retransmission time, the PSAP resends the MSD request packet to the IVS, requesting to obtain the MSD data; the retransmission time is proportional to the RTT; if the PSAP still does not receive the RTCP MSD data packet sent by the IVS after the maximum number of retransmissions is reached, the PSAP will try to retransmit the MSD request packet at a fixed time until the PSAP receives the RTCP MSD data packet sent by the IVS; the fixed time is much longer than the retransmission time.2.根据权利要求1所述的通过RTCP上报MSD的方法，其特征是，所述本地时间字段、远程时间字段、延迟时间字段或者记录绝对时间，或者记录相对时间；所述本地时间字段、远程时间字段、延迟时间字段的长度均为2字节；如果需记录的时间以二进制表示后超过2各字节，只取低16位记录到相应字段中。2. The method for reporting MSD through RTCP according to claim 1 is characterized in that the local time field, remote time field, and delayed time field either record absolute time or relative time; the length of the local time field, remote time field, and delayed time field are all 2 bytes; if the time to be recorded exceeds 2 bytes after being expressed in binary, only the lower 16 bits are recorded in the corresponding field.3. 根据权利要求1所述的通过RTCP上报MSD的方法，其特征是，所述步骤S31中，如果IVS收到PSAP发来的MSD请求包，则IVS停止每隔固定时间的尝试重传RTCP MSD数据包，立即响应MSD请求包，发送RTCP MSD数据包给PSAP。3. The method for reporting MSD via RTCP according to claim 1, wherein in step S31, if the IVS receives the MSD request packet from the PSAP, the IVS stops attempting to retransmit the RTCP MSD data packet at fixed intervals, immediately responds to the MSD request packet, and sends the RTCP MSD data packet to the PSAP.4.一种通过RTCP上报MSD的装置，其特征是，包括增加子类型单元、同步握手单元、以及推送数据单元；4. A device for reporting MSD via RTCP, characterized by comprising a subtype adding unit, a synchronous handshake unit, and a push data unit;所述增加子类型单元用于在APP类型的实时传输控制协议RTCP包中增加6种子类型，分别是用于车载系统IVS向公共安全应答点PSAP握手的“RTCP同步包”、用于PSAP收到RTCP同步包后向IVS发送响应的“RTCP确认包”、用于IVS收到RTCP确认包后发送给PSAP的“RTCP告知收到确认包”、用于PSAP请求IVS发送最小数据集MSD的“MSD请求包”、用于IVS向PSAP发送MSD数据的“RTCP MSD数据包”、用于PSAP收到MSD数据后向IVS发送确认信息的“RTCP告知收到MSD数据包”；The added subtype unit is used to add 6 subtypes in the real-time transport control protocol RTCP packet of the APP type, namely, an "RTCP synchronization packet" for the in-vehicle system IVS to shake hands with the public safety answering point PSAP, an "RTCP confirmation packet" for the PSAP to send a response to the IVS after receiving the RTCP synchronization packet, an "RTCP notification receipt confirmation packet" for the IVS to send to the PSAP after receiving the RTCP confirmation packet, an "MSD request packet" for the PSAP to request the IVS to send a minimum data set MSD, an "RTCP MSD data packet" for the IVS to send MSD data to the PSAP, and an "RTCP notification receipt MSD data packet" for the PSAP to send confirmation information to the IVS after receiving the MSD data;所述RTCP同步包中设置有本地时间字段，用来记录IVS发送RTCP同步包时IVS当前的时间点；The RTCP synchronization packet is provided with a local time field, which is used to record the current time point of the IVS when the IVS sends the RTCP synchronization packet;所述RTCP确认包中设置有远程时间字段和延迟时间字段；远程时间字段用来记录PSAP收到的RTCP同步包里面的本地时间字段的内容；延迟时间字段用来记录PSAP在收到RTCP同步包后到发送RTCP确认包之间所延迟的时间；The RTCP acknowledgment packet is provided with a remote time field and a delay time field; the remote time field is used to record the content of the local time field in the RTCP synchronization packet received by the PSAP; the delay time field is used to record the time delayed between the PSAP receiving the RTCP synchronization packet and sending the RTCP acknowledgment packet;所述RTCP告知收到确认包中设置有往返时间字段，用来记录IVS在收到RTCP确认包后，计算出的RTCP同步包和RTCP确认包在网络传输的往返时间；The RTCP notification confirmation packet is provided with a round trip time field, which is used to record the round trip time of the RTCP synchronization packet and the RTCP confirmation packet calculated by the IVS after receiving the RTCP confirmation packet.所述RTCP MSD数据包中设置有MSD数据字段，用来记录IVS向PSAP发送的MSD数据；The RTCP MSD data packet is provided with an MSD data field for recording the MSD data sent by the IVS to the PSAP;所述同步握手单元用于在紧急呼叫eCall建立后，IVS向PSAP发送RTCP同步包；PSAP收到RTCP同步包后，向IVS回复RTCP确认包；IVS收到RTCP确认包后，计算RTCP同步包和RTCP确认包在网络传输的往返时间RTT，并向PSAP回复携带RTT的RTCP告知收到确认包；RTT＝time_cur―time_last―time_delay；time_cur表示当前时间；time_last表示RTCP确认包中的远程时间字段的内容，也就是IVS上次发送RTCP同步包的时间；time_delay表示RTCP确认包中的延迟时间字段的内容；RTT用于IVS或PSAP后续的超时重传策略；The synchronous handshake unit is used for the IVS to send an RTCP synchronization packet to the PSAP after the emergency call eCall is established; after the PSAP receives the RTCP synchronization packet, it replies with an RTCP confirmation packet to the IVS; after the IVS receives the RTCP confirmation packet, it calculates the round-trip time RTT of the RTCP synchronization packet and the RTCP confirmation packet in the network transmission, and replies to the PSAP with an RTCP carrying RTT to inform the PSAP of the receipt of the confirmation packet; RTT = time_cur - time_last - time_delay; time_cur represents the current time; time_last represents the content of the remote time field in the RTCP confirmation packet, that is, the time when the IVS last sent the RTCP synchronization packet; time_delay represents the content of the delay time field in the RTCP confirmation packet; RTT is used for the subsequent timeout retransmission strategy of the IVS or PSAP;所述推送数据单元用于在eCall通话过程中，IVS向PSAP发送RTCP MSD数据包，其中携带有MSD数据；如果PSAP顺利地收到了RTCP MSD数据包，则向IVS回复RTCP告知收到MSD数据包；当IVS在重传时间后仍未收到RTCP告知收到MSD数据包，IVS向PSAP重新发送RTCP MSD数据包，其中携带有MSD数据；重传时间与RTT成正比；如果到达最大重传次数后，IVS还是没有收到PSAP发来的RTCP告知收到MSD数据包，后面IVS每隔固定时间尝试重传一次RTCP MSD数据包，直至IVS收到PSAP发来的RTCP告知收到MSD数据包为止；所述固定时间远大于所述重传时间；如果IVS的MSD数据有更新，则IVS停止每隔固定时间的重传尝试，改为发送新的MSD数据给PSAP；The push data unit is used for the IVS to send an RTCP MSD data packet carrying MSD data to the PSAP during an eCall call; if the PSAP successfully receives the RTCP MSD data packet, it replies to the IVS with an RTCP notification of receipt of the MSD data packet; when the IVS still does not receive the RTCP notification of receipt of the MSD data packet after the retransmission time, the IVS resends the RTCP MSD data packet carrying MSD data to the PSAP; the retransmission time is proportional to the RTT; if the IVS still does not receive the RTCP notification of receipt of the MSD data packet from the PSAP after the maximum number of retransmissions is reached, the IVS will attempt to retransmit the RTCP MSD data packet at a fixed time interval until the IVS receives the RTCP notification of receipt of the MSD data packet from the PSAP; the fixed time is much longer than the retransmission time; if the MSD data of the IVS is updated, the IVS stops the retransmission attempt at the fixed time interval and sends new MSD data to the PSAP instead;或者，将推送数据单元替换为拉取数据单元；Alternatively, replace the push data unit with the pull data unit;所述拉取数据单元用于在eCall通话过程中，PSAP主动向IVS发送MSD请求包，请求获取MSD数据；IVS收到MSD请求包后，向PSAP发送RTCP MSD数据包，其中携带有MSD数据；如果PSAP顺利地收到了RTCP MSD数据包，则向IVS回复RTCP告知收到MSD数据包；当PSAP在重传时间后仍未收到RTCP MSD数据包，PSAP向IVS重新发送MSD请求包，请求获取MSD数据；重传时间与RTT成正比；如果到达最大重传次数后，PSAP还是没有收到IVS发来的RTCP MSD数据包，后面PSAP每隔固定时间尝试重传一次MSD请求包，直至PSAP收到IVS发来的RTCP MSD数据包为止；所述固定时间远大于所述重传时间。The data pulling unit is used for the PSAP to actively send an MSD request packet to the IVS during an eCall call to request MSD data; after receiving the MSD request packet, the IVS sends an RTCP MSD data packet carrying the MSD data to the PSAP; if the PSAP successfully receives the RTCP MSD data packet, it replies RTCP to the IVS to inform it of the receipt of the MSD data packet; when the PSAP still does not receive the RTCP MSD data packet after the retransmission time, the PSAP resends the MSD request packet to the IVS to request MSD data; the retransmission time is proportional to the RTT; if the PSAP still does not receive the RTCP MSD data packet sent by the IVS after the maximum number of retransmissions is reached, the PSAP will try to retransmit the MSD request packet once at a fixed time until the PSAP receives the RTCP MSD data packet sent by the IVS; the fixed time is much longer than the retransmission time.