CN115842800B

CN115842800B - Mail downloading and inquiring method, system and related device in Beidou communication system

Info

Publication number: CN115842800B
Application number: CN202111212370.8A
Authority: CN
Inventors: 钱锋; 甘雯昱; 朱颖; 朱旭东; 徐海博; 王宝
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2021-08-06
Filing date: 2021-10-18
Publication date: 2024-05-14
Anticipated expiration: 2041-10-18
Also published as: CN115842800A

Abstract

The application discloses a mail downloading and inquiring method, a system and a related device in a Beidou communication system, wherein the method can comprise the following steps: the terminal can send a mail downloading inquiry request message to the north fight network equipment, wherein the mail downloading inquiry request message comprises a service type field and a message ID field; the service type field is used for indicating the service type of the mail downloading inquiry request message, and the message ID field is used for indicating the ID of the mail which is successfully received by the terminal last time. The terminal receives a letter downloading inquiry result message sent by Beidou network equipment; the mail downloading inquiry result message comprises a mail original sending time field and a mail content field; the original sending time field of the letter is used for indicating the original sending time of the letter content in the letter content field; the letter content field is used to indicate the letter content that the one or more target terminals send to the terminal. Thus, the user can receive letters sent by other users in the cellular network in the Beidou network.

Description

Mail downloading and inquiring method, system and related device in Beidou communication system

Technical Field

The application relates to the technical field of Beidou communication, in particular to a mail downloading and inquiring method, system and related device in a Beidou communication system.

Background

The Beidou satellite navigation system is an important infrastructure which is independently developed in China and integrates positioning, time service and communication. The Beidou short message system utilizes a Beidou satellite system to realize the sending of short message information. The method is particularly suitable for communication in areas where mobile communication is uncovered or not covered or the communication system is destroyed, such as oceans, deserts, grasslands, unmanned areas and the like. When the terminal is in an environment where mobile communication is not covered, or coverage is not available, or a communication system is destroyed for communication, the terminal cannot timely learn whether there is a letter sent to the terminal through a cellular network or a wireless local area network (for example, wireless fidelity (WIRELESSFIDELITY, wi-Fi)).

Therefore, how to obtain letters sent to the terminal by the terminal under other cellular networks is a problem to be solved when the environment where the terminal is located does not have a cellular network or a wireless local area network.

Disclosure of Invention

The embodiment of the application provides a mail downloading and inquiring method, a system and a related device in a Beidou communication system. By the mail downloading query method in the Beidou communication system, when the environment where the terminal is located does not have a cellular network or a wireless local area network, the terminal can download mails sent to the terminal by other terminals.

In a first aspect, an embodiment of the present application provides a mail downloading and querying method in a beidou communication system, where the method may include: the first terminal sends a mail downloading inquiry request message to the north-fighting network equipment, wherein the mail downloading inquiry request message is used for downloading the content of the mail sent to the first terminal by one or more second terminals, the mail downloading inquiry request message comprises a message ID field, the message ID field is used for indicating the ID of the first mail which is successfully received by the first terminal last time, and the ID of the first mail is used for indicating the Beidou network equipment to delete the first mail; the method comprises the steps that a first terminal receives a letter downloading inquiry result message sent by Beidou network equipment; the mail downloading inquiry result message comprises a mail content field and a mail ID field; the letter content field is used for indicating the content of a second letter sent by one or more second terminals to the first terminal, the letter ID field is used for indicating the ID of the second letter, the ID of the second letter is arranged in sequence with the ID of the first letter, and the ID of the second letter is arranged behind the ID of the first letter.

In this way, the terminal may also download letters sent by other terminals to the first terminal in the case where there is no cellular network or wireless local area network in the environment in which the first terminal is located.

With reference to the first aspect, in one possible implementation manner, the letter download query request packet further includes a service type field, where in a case that the service type field is a first value, the service type field is used to indicate that the letter download query request packet is used to download content of a second letter sent to the first terminal by the second terminal in the whitelist; in the case that the service type field is the second value, the service type field is used for indicating that the mail downloading inquiry request message is used for downloading the content of the second mail sent to the first terminal by the second terminal in the non-white list; the service type field is used for indicating a letter downloading inquiry request message to be used for downloading the contents of the second letters sent to the first terminal by all the second terminals under the condition that the service type field is a third value; the first terminal is provided with a white list, and the white list is used for storing the identification of the second terminal associated with the first terminal and the serial number of the second terminal associated with the first terminal.

Thus, the first terminal may specify a specific service type of the letter download query request message through the service type field. After receiving the mail downloading inquiry request message, the Beidou network equipment can acquire the service type of the mail downloading inquiry request message through the service type field.

With reference to the first aspect, in a possible implementation manner, in a case that the service type field is a first value, the mail downloading query request packet further includes a first sender ID field, where the first sender ID field is used to indicate a sequence number of the second terminal in the whitelist; in the case that the traffic type field is the second value, the letter download query request message further includes a first sender ID field, where the first sender ID field is used to indicate an identity of the second terminal in the non-whitelist.

In this way, after receiving the mail downloading query request message, the Beidou network equipment can determine which terminal of the first terminal is to download the mail sent to the first terminal according to the identifier in the ID field of the sender.

With reference to the first aspect, in one possible implementation manner, the mail downloading query request packet further includes a receipt indication field, where the receipt indication field may be used to indicate whether a receiving device (e.g., a beidou network device) of the mail downloading query request packet needs to reply to the application layer receipt to the first terminal. The application layer receipt may be used to indicate whether the receiving device successfully received the letter download query request message. The length of the response piece indication field may be 1bit. When the receipt indication field is a value D1 (e.g., 0), the receiving device, which may be used to indicate that the letter download query request message does not need to reply to the first terminal with an application layer receipt. When the receipt indication field is a value D2 (e.g., 1), it may be used to indicate that the receiving device of the mail download query request message needs to reply to the application layer receipt to the first terminal.

With reference to the first aspect, in a possible implementation manner, the mail downloading query request packet further includes an encryption indication field, where the encryption indication field may be used to indicate whether the mail downloading query request packet is encrypted.

Further, in one possible implementation, the encryption indication field may be 2 bits in length.

With reference to the first aspect, in a possible implementation manner, the mail downloading query request packet further includes a compression indication field, where the compression indication field may be used to indicate whether the mail downloading query request packet is compressed or not.

Further, in one possible implementation, the length of the compressed indication field may be 2 bits.

With reference to the first aspect, in a possible implementation manner, the mail downloading query request message further includes an application layer authentication code field, where the application layer authentication code field may be used for authentication of the application layer.

Further, in one possible implementation, the application layer authentication code field may be 16 bits in length.

With reference to the first aspect, in a possible implementation manner, the mail downloading query result message further includes a whitelist indication field and a second sender ID field; the white list indication field is used for indicating the mobile phone number of the second terminal in the non-white list in the second sender ID field under the condition that the white list indication field is a fourth value; and under the condition that the white list indication field is a fifth value, the white list indication field is used for indicating that the second sender ID field is the serial number of the second terminal in the white list.

Thus, after receiving the mail downloading query result message, the first terminal knows how to analyze the second sender ID field in the mail downloading query result message according to the white list indication field. The first terminal can determine which second terminal sent the letter to the first terminal based on the second sender ID field.

With reference to the first aspect, in one possible implementation manner, the letter download query result packet further includes a message type indication field, where in a case that the message type indication field is a sixth value, the message type indication field is used to indicate that the letter download query result packet indicates a number of second letters sent by the one or more second terminals to the first terminal; and in the case that the message type indication field is a seventh value, the message type indication field is used for indicating that the letter download inquiry result message indicates the content of the second letters sent by the one or more second terminals to the first terminal.

Thus, after receiving the letter download inquiry result message, the first terminal can determine the type of the letter download inquiry result message according to the message type indication field in the letter download inquiry result message. Therefore, the first terminal can correctly analyze the mail downloading inquiry result message.

With reference to the first aspect, in a possible implementation manner, the letter download query result packet further includes a letter download completion indication field; the mail downloading completion indication field is used for indicating whether a mail sent by the second terminal to the first terminal exists after the Beidou network equipment sends the second mail under the condition that the service type field is a first value or a second value; and if the service type field is the third value, the letter download completion indication field is used for indicating whether all the letters sent by the second terminal to the first terminal exist after the Beidou network equipment sends the second letters.

In this way, the first terminal can determine whether there is a letter to be downloaded subsequently according to the letter download completion indication field.

With reference to the first aspect, in one possible implementation manner, the letter download query result packet further includes an original message sending time field, where the original message sending time field is used to indicate an original sending time of the second letter.

In this way, the first terminal can determine the original time of transmission of the letter from the original message time field.

With reference to the first aspect, in a possible implementation manner, the letter download query result packet further includes a location information indication field; the position information indication field is used for indicating that no position information field exists in the subsequent field when the position indication field is an eighth value, and is used for indicating that the position information field exists in the subsequent field when the position indication field is a ninth value.

Thus, the first terminal can correctly analyze the subsequent fields in the mail downloading inquiry result message according to the position information indication field.

With reference to the first aspect, in a possible implementation manner, in a case that the location information indication field is a ninth value, the letter download query result packet further includes a location information field; the location information field is used to indicate location information of the second terminal indicated by the sender ID field.

Thus, the user of the first terminal finds the user of the second terminal as soon as possible according to the position information sent by the second terminal. Or when the first terminal is not far from the second terminal, but the second terminal is positioned at a position with cellular network coverage, and the first terminal is positioned at a position without cellular network coverage. Then, the first terminal can find the place covered by the cellular network as soon as possible according to the position information sent by the second terminal. In this way, the first terminal can also get in touch with the second terminal as soon as possible.

With reference to the first aspect, in one possible implementation manner, the letter download query result packet further includes a data format indication field, where the data format indication field is used to indicate a format of the content of the second letter.

In this way, the first terminal can correctly parse the content of the second letter according to the data format indication field.

With reference to the first aspect, in one possible implementation manner, the mail downloading query result packet further includes an encryption indication field, where the encryption indication field may be used to indicate whether the mail downloading query result packet is encrypted.

With reference to the first aspect, in one possible implementation manner, the letter download query result packet further includes a compression indication field, where the compression indication field may be used to indicate whether the letter download query result packet is compressed.

With reference to the first aspect, in a possible implementation manner, the mail downloading query result message further includes an application layer authentication code field, where the application layer authentication code field may be used for authentication of the application layer.

With reference to the first aspect, in one possible implementation manner, before the first terminal sends the letter download query request packet to the north-bucket network device, the method may further include: the first terminal detects a first operation and generates a letter download inquiry request message based on the first operation.

With reference to the first aspect, in one possible implementation manner, the sending, by the first terminal, a letter download query request packet to the north bucket network device includes: the first terminal downloads a mail downloading inquiry request message to a message data convergence MDCP layer of the first terminal at an application APP layer, and the message data convergence MDCP layer is used as an MDCP service data unit SDU of the MDCP layer; the first terminal adds MDCP SDU into filling data and redundant length indication field, and then splits the MDCP SDU into one or more MDCP protocol data units PDU; the one or more MDCP PDUs comprise a first MDCP PDU; the first terminal transmits a first MDCP PDU to a satellite link control SLC layer to serve as an SLC SDU of the SLC layer; the first terminal splits the SLC SDU into one or more SLC PDUs; and the first terminal sends the one or more SLC PDUs to the Beidou network equipment.

With reference to the first aspect, in one possible implementation manner, the receiving, by a first terminal, a letter download query result packet sent by the beidou network device includes: the method comprises the steps that a first terminal receives P SLC PDUs sent by Beidou network equipment; p is a positive integer; the first terminal spells P SLC PDUs into Q SLC SDUs at the SLC layer; q is a positive integer, and Q is less than or equal to P; the first terminal uploads Q SLC SDUs to an MDCP layer to serve as Q MDCP PDUs of the MDCP layer; the first terminal spells Q MDCP PDUs into MDCP SDUs in an MDCP layer; and the first terminal removes the filling data and the redundant length indication field from the MDCP SDU at the MDCP layer, and then uploads the data to the APP layer to serve as a letter downloading query result message.

With reference to the first aspect, in one possible implementation manner, after the first terminal receives the letter download query result message sent by the beidou network device, the method may further include: the first terminal analyzes the content of the second letters of the first terminal, which is sent by one or more second terminals in the letter content field in the letter downloading inquiry result message; the first terminal displays the content of the second letter in the display screen.

In a second aspect, an embodiment of the present application provides a mail downloading and querying method in a beidou communication system, where the method may include: the Beidou network equipment receives a mail downloading query request message sent by a first terminal, wherein the mail downloading query request message is used for downloading the content of a mail sent by one or more second terminals to the first terminal, the mail downloading query request message comprises a message ID field, the message ID field is used for indicating the ID of the first mail which is successfully received by the first terminal last time, and the ID of the first mail is used for indicating the Beidou network equipment to delete the first mail; based on the mail downloading query request message, the Beidou network equipment generates a mail downloading query result message, wherein the mail downloading query result message comprises a mail content field and a mail ID field; the letter content field is used for indicating the content of a second letter sent to the first terminal by one or more second terminals, the letter ID field is used for indicating the ID of the second letter, the ID of the second letter is arranged in sequence with the ID of the first letter, and the ID of the second letter is arranged behind the ID of the first letter; and the Beidou network equipment sends a letter downloading query result message to the first terminal.

With reference to the second aspect, in one possible implementation manner, the letter download query request packet further includes a service type field, where in a case that the service type field is a first value, the service type field is used to indicate that the letter download query request packet is used to download content of a second letter sent to the first terminal by the second terminal in the whitelist; in the case that the service type field is the second value, the service type field is used for indicating that the mail downloading inquiry request message is used for downloading the content of the second mail sent to the first terminal by the second terminal in the non-white list; the service type field is used for indicating a letter downloading inquiry request message to be used for downloading the contents of the second letters sent to the first terminal by all the second terminals under the condition that the service type field is a third value; the first terminal is provided with a white list, and the white list is used for storing the identification of the second terminal associated with the first terminal and the serial number of the second terminal associated with the first terminal.

With reference to the second aspect, in one possible implementation manner, in a case that the service type field is a first value, the mail downloading query request packet further includes a first sender ID field, where the first sender ID field is used to indicate a sequence number of the second terminal in the whitelist; in the case that the traffic type field is the second value, the letter download query request message further includes a first sender ID field, where the first sender ID field is used to indicate an identity of the second terminal in the non-whitelist.

With reference to the second aspect, in one possible implementation manner, the mail downloading query request packet further includes a receipt indication field, where the receipt indication field may be used to indicate whether a receiving device (e.g., a beidou network device) of the mail downloading query request packet needs to reply to the application layer receipt to the first terminal. The application layer receipt may be used to indicate whether the receiving device successfully received the letter download query request message. The length of the response piece indication field may be 1bit. When the receipt indication field is a value D1 (e.g., 0), the receiving device, which may be used to indicate that the letter download query request message does not need to reply to the first terminal with an application layer receipt. When the receipt indication field is a value D2 (e.g., 1), it may be used to indicate that the receiving device of the mail download query request message needs to reply to the application layer receipt to the first terminal.

With reference to the second aspect, in one possible implementation manner, the mail download query request packet further includes an encryption indication field, where the encryption indication field may be used to indicate whether the mail download query request packet is encrypted.

With reference to the second aspect, in one possible implementation manner, the mail downloading query request packet further includes a compression indication field, where the compression indication field may be used to indicate whether the mail downloading query request packet is compressed or not.

With reference to the second aspect, in one possible implementation manner, the mail download query request message further includes an application layer authentication code field, where the application layer authentication code field may be used for authentication of the application layer.

With reference to the second aspect, in one possible implementation manner, the mail downloading query result packet further includes a whitelist indication field and a second sender ID field; the white list indication field is used for indicating the mobile phone number of the second terminal in the non-white list in the second sender ID field under the condition that the white list indication field is a fourth value; and under the condition that the white list indication field is a fifth value, the white list indication field is used for indicating that the second sender ID field is the serial number of the second terminal in the white list.

With reference to the second aspect, in one possible implementation manner, the letter download query result packet further includes a message type indication field, where in the case that the message type indication field is a sixth value, the message type indication field is used to indicate that the letter download query result packet indicates the number of second letters sent by the one or more second terminals to the first terminal; and in the case that the message type indication field is a seventh value, the message type indication field is used for indicating that the letter download inquiry result message indicates the content of the second letters sent by the one or more second terminals to the first terminal.

With reference to the second aspect, in a possible implementation manner, the letter download query result packet further includes a letter download completion indication field; the mail downloading completion indication field is used for indicating whether a mail sent by the second terminal to the first terminal exists after the Beidou network equipment sends the second mail under the condition that the service type field is a first value or a second value; and if the service type field is the third value, the letter download completion indication field is used for indicating whether all the letters sent by the second terminal to the first terminal exist after the Beidou network equipment sends the second letters.

With reference to the second aspect, in one possible implementation manner, the letter download query result packet further includes an original message sending time field, where the original message sending time field is used to indicate an original sending time of the second letter.

With reference to the second aspect, in a possible implementation manner, the letter download query result packet further includes a location information indication field; the position information indication field is used for indicating that no position information field exists in the subsequent field when the position indication field is an eighth value, and is used for indicating that the position information field exists in the subsequent field when the position indication field is a ninth value.

With reference to the second aspect, in a possible implementation manner, in a case that the location information indication field is a ninth value, the letter download query result packet further includes a location information field; the location information field is used to indicate location information of the second terminal indicated by the sender ID field.

With reference to the second aspect, in one possible implementation manner, the letter download query result packet further includes a data format indication field, where the data format indication field is used to indicate a format of the content of the second letter.

With reference to the second aspect, in one possible implementation manner, the letter download query result packet further includes an encryption indication field, where the encryption indication field may be used to indicate whether the letter download query result packet is encrypted.

With reference to the second aspect, in one possible implementation manner, the letter download query result packet further includes a compression indication field, where the compression indication field may be used to indicate whether the letter download query result packet is compressed.

With reference to the second aspect, in one possible implementation manner, the mail downloading query result message further includes an application layer authentication code field, where the application layer authentication code field may be used for authentication of the application layer.

With reference to the second aspect, in one possible implementation manner, the receiving, by the beidou network device, a letter download query request packet sent by the first terminal includes: the Beidou network equipment receives X SLC PDUs sent by the first terminal; x is a positive integer; the Beidou network equipment spells the X SLC PDUs into Y SLC SDUs at the SLC layer; y is a positive integer, and is smaller than or equal to X, and the Beidou network equipment uploads Y SLC SDUs to the MDCP layer to serve as Y MDCP PDUs of the MDCP layer; the Beidou network equipment splices Y MDCP PDUs into MDCP SDUs at an MDCP layer; and the Beidou network equipment removes the filling data and the redundant length indication field from the MDCP SDU at the MDCP layer, and uploads the data to the APP layer to serve as a mail downloading query request message.

With reference to the second aspect, in one possible implementation manner, based on the letter download query request packet, the generating, by the beidou network device, a letter download query result packet includes: the Beidou network equipment inquires the content of the second letters sent to the first terminal by one or more second terminals after the sending time of the first letters in the short message center according to the letter downloading inquiry request message; and the Beidou network equipment generates a letter downloading query result message based on the content of the second letter.

With reference to the second aspect, in one possible implementation manner, the sending, by the beidou network device, a letter download query result packet to the first terminal includes: the Beidou network equipment downloads a letter downloading query result message to a message data convergence MDCP layer of the Beidou network equipment at an application APP layer, and the message data convergence MDCP layer is used as an MDCP service data unit SDU of the MDCP layer; the Beidou network equipment adds MDCP SDUs into filling data and redundant length indication fields and then splits the MDCP SDUs into one or more MDCP protocol data units PDU; the one or more MDCP PDUs comprise a second MDCP PDU; the first terminal transmits the second MDCP PDU to a satellite link control SLC layer to serve as an SLC SDU of the SLC layer; the Beidou network equipment splits the SLC SDU into one or more SLC PDUs; and the Beidou network equipment sends one or more SLC PDUs to the first terminal.

In a third aspect, a beidou communication system is provided, the system may include a terminal and a beidou network device, wherein:

the first terminal is used for sending a mail downloading query request message to the Beidou network equipment, the mail downloading query request message is used for downloading the content of the mails sent to the first terminal by one or more second terminals, the mail downloading query request message comprises a message ID field, the message ID field is used for indicating the ID of the first mail which is successfully received last time by the first terminal, and the ID of the first mail is used for indicating the Beidou network equipment to delete the first mail;

The Beidou network equipment is used for receiving a mail downloading query request message sent by the first terminal;

The Beidou network equipment is used for generating a mail downloading query result message based on the mail downloading query request message, wherein the mail downloading query result message comprises a mail content field and a mail ID field; the letter content field is used for indicating the content of a second letter sent by one or more second terminals to the first terminal after the sending time of the first letter, the letter ID field is used for indicating the ID of the second letter, the ID of the second letter is arranged in sequence with the ID of the first letter, and the ID of the second letter is arranged after the ID of the first letter;

the Beidou network equipment is used for sending a letter downloading query result message to the first terminal;

the first terminal is used for receiving a mail downloading inquiry result message sent by the Beidou network equipment.

With reference to the third aspect, in one possible implementation manner, the letter download query request packet further includes a service type field, where in a case that the service type field is a first value, the service type field is used to indicate that the letter download query request packet is used to download content of a second letter sent to the first terminal by the second terminal in the whitelist; in the case that the service type field is the second value, the service type field is used for indicating that the mail downloading inquiry request message is used for downloading the content of the second mail sent to the first terminal by the second terminal in the non-white list; the service type field is used for indicating a letter downloading inquiry request message to be used for downloading the contents of the second letters sent to the first terminal by all the second terminals under the condition that the service type field is a third value; the first terminal is provided with a white list, and the white list is used for storing the identification of the second terminal associated with the first terminal and the serial number of the second terminal associated with the first terminal.

With reference to the third aspect, in one possible implementation manner, in a case that the service type field is a first value, the mail downloading query request packet further includes a first sender ID field, where the first sender ID field is used to indicate a sequence number of the second terminal in the whitelist; in the case that the traffic type field is the second value, the letter download query request message further includes a first sender ID field, where the first sender ID field is used to indicate an identity of the second terminal in the non-whitelist.

With reference to the third aspect, in one possible implementation manner, the mail downloading query request packet further includes a receipt indication field, where the receipt indication field may be used to indicate whether a receiving device (e.g., a beidou network device) of the mail downloading query request packet needs to reply to the application layer receipt to the first terminal. The application layer receipt may be used to indicate whether the receiving device successfully received the letter download query request message. The length of the response piece indication field may be 1bit. When the receipt indication field is a value D1 (e.g., 0), the receiving device, which may be used to indicate that the letter download query request message does not need to reply to the first terminal with an application layer receipt. When the receipt indication field is a value D2 (e.g., 1), it may be used to indicate that the receiving device of the mail download query request message needs to reply to the application layer receipt to the first terminal.

With reference to the third aspect, in one possible implementation manner, the mail download query request packet further includes an encryption indication field, where the encryption indication field may be used to indicate whether the mail download query request packet is encrypted.

With reference to the third aspect, in one possible implementation manner, the mail downloading query request packet further includes a compression indication field, where the compression indication field may be used to indicate whether the mail downloading query request packet is compressed.

With reference to the third aspect, in one possible implementation manner, the mail download query request packet further includes an application layer authentication code field, where the application layer authentication code field may be used for authentication of the application layer.

With reference to the third aspect, in one possible implementation manner, the mail downloading query result packet further includes a whitelist indication field and a second sender ID field; the white list indication field is used for indicating the mobile phone number of the second terminal in the non-white list in the second sender ID field under the condition that the white list indication field is a fourth value; and under the condition that the white list indication field is a fifth value, the white list indication field is used for indicating that the second sender ID field is the serial number of the second terminal in the white list.

With reference to the third aspect, in one possible implementation manner, the letter download query result packet further includes a message type indication field, where in the case that the message type indication field is a sixth value, the message type indication field is used to indicate that the letter download query result packet indicates the number of second letters sent by the one or more second terminals to the first terminal; and in the case that the message type indication field is a seventh value, the message type indication field is used for indicating that the letter download inquiry result message indicates the content of the second letters sent by the one or more second terminals to the first terminal.

With reference to the third aspect, in one possible implementation manner, the letter download query result packet further includes a letter download completion indication field; the mail downloading completion indication field is used for indicating whether a mail sent by the second terminal to the first terminal exists after the Beidou network equipment sends the second mail under the condition that the service type field is a first value or a second value; and if the service type field is the third value, the letter download completion indication field is used for indicating whether all the letters sent by the second terminal to the first terminal exist after the Beidou network equipment sends the second letters.

With reference to the third aspect, in one possible implementation manner, the letter download query result packet further includes an original message sending time field, where the original message sending time field is used to indicate an original sending time of the second letter.

With reference to the third aspect, in one possible implementation manner, the letter download query result packet further includes a location information indication field; the position information indication field is used for indicating that no position information field exists in the subsequent field when the position indication field is an eighth value, and is used for indicating that the position information field exists in the subsequent field when the position indication field is a ninth value.

With reference to the third aspect, in one possible implementation manner, in a case that the location information indication field is a ninth value, the letter download query result packet further includes a location information field; the location information field is used to indicate location information of the second terminal indicated by the sender ID field.

With reference to the third aspect, in one possible implementation manner, the letter download query result packet further includes a data format indication field, where the data format indication field is used to indicate a format of the content of the second letter.

With reference to the third aspect, in one possible implementation manner, the letter download query result packet further includes an encryption indication field, where the encryption indication field may be used to indicate whether the letter download query result packet is encrypted.

With reference to the third aspect, in one possible implementation manner, the letter download query result packet further includes a compression indication field, where the compression indication field may be used to indicate whether the letter download query result packet is compressed.

With reference to the third aspect, in one possible implementation manner, the mail downloading query result message further includes an application layer authentication code field, where the application layer authentication code field may be used for authentication of the application layer.

With reference to the third aspect, in one possible implementation manner, the first terminal is further configured to: and detecting a first operation, and generating a mail downloading inquiry request message based on the first operation.

With reference to the third aspect, in one possible implementation manner, the first terminal is specifically configured to: message data of a letter download inquiry request message is issued to a first terminal by an application APP layer to be converged into an MDCP layer as an MDCP service data unit SDU of the MDCP layer; after adding the MDCP SDU into the filling data and the redundant length indication field, splitting the MDCP SDU into one or more MDCP protocol data units PDU; the one or more MDCP PDUs comprise a first MDCP PDU; the first MDCP PDU is issued to a satellite link control SLC layer and used as an SLC SDU of the SLC layer; splitting the SLC SDU into one or more SLC PDUs; and sending the one or more SLC PDUs to the Beidou network equipment.

With reference to the third aspect, in one possible implementation manner, the first terminal may be specifically configured to: receiving P SLC PDUs sent by Beidou network equipment; p is a positive integer; splicing the P SLC PDUs into Q SLC SDUs at the SLC layer; q is a positive integer, and Q is less than or equal to P; uploading the Q SLC SDUs to an MDCP layer to serve as Q MDCP PDUs of the MDCP layer; splicing the Q MDCP PDUs into MDCP SDUs in an MDCP layer; and after the MDCP SDU removes the filling data and the redundant length indication field, uploading the filling data and the redundant length indication field to the APP layer to serve as a letter downloading query result message.

With reference to the third aspect, in one possible implementation manner, the first terminal may further be configured to: analyzing the content of the second letters of the first terminal, which are sent by one or more second terminals in the letter content field in the letter downloading inquiry result message; the content of the second letter is displayed in the display screen.

With reference to the third aspect, in one possible implementation manner, the beidou network device may be configured to: receiving X SLC PDUs sent by the first terminal; x is a positive integer; splicing the X SLC PDUs into Y SLC SDUs at the SLC layer; y is a positive integer, and Y is less than or equal to X; uploading Y SLC SDUs to the MDCP layer to serve as Y MDCP PDUs of the MDCP layer; splicing Y MDCP PDUs into MDCP SDU in the MDCP layer; and after the MDCP SDU removes the filling data and the redundant length indication field, uploading the filling data and the redundant length indication field to the APP layer to serve as a letter downloading query request message.

With reference to the third aspect, in one possible implementation manner, the beidou network device may be configured to: inquiring the content of the second letters sent to the first terminal by one or more second terminals after the sending time of the first letters in a short message center according to the letter downloading inquiry request message; and generating a letter downloading query result message based on the content of the second letter.

With reference to the third aspect, in one possible implementation manner, the beidou network device may be configured to: message data of a letter download inquiry result message is issued to a Beidou network device at an application APP layer to be converged into an MDCP layer, and the message data is used as an MDCP service data unit SDU of the MDCP layer; after adding the MDCP SDU into the filling data and the redundant length indication field, splitting the MDCP SDU into one or more MDCP protocol data units PDU; the one or more MDCP PDUs comprise a second MDCP PDU; the second MDCP PDU is issued to a satellite link control SLC layer and used as an SLC SDU of the SLC layer; splitting the SLC SDU into one or more SLC PDUs; one or more SLC PDUs are sent to the first terminal.

With reference to the third aspect, in a possible implementation manner, the terminal may further perform the method in any one of the possible implementation manners of the first aspect.

In a fourth aspect, the present application provides a communications apparatus comprising one or more processors, one or more memories, and a transceiver. The transceiver, the one or more memories being coupled to one or more processors, the one or more memories being for storing computer program code comprising computer instructions that, when executed by the one or more processors, cause the communications apparatus to perform the method in any of the possible implementations of the first aspect described above.

The communication device may be a terminal or other product-form device.

In a fifth aspect, the present application provides a communications apparatus comprising one or more processors, one or more memories, and a transceiver. The transceiver, the one or more memories being coupled to one or more processors, the one or more memories being for storing computer program code comprising computer instructions that, when executed by the one or more processors, cause the communications apparatus to perform the method of any of the possible implementations of the second aspect described above.

The communication device may be a Beidou network device, or any network element or a combination of multiple network elements in the Beidou network device.

In a sixth aspect, the application provides a computer storage medium comprising computer instructions which, when run on a computer, cause the computer to perform the method of any one of the possible implementations of the first aspect.

In a seventh aspect, the present application provides a computer storage medium comprising computer instructions which, when run on a computer, cause the computer to perform the method of any one of the possible implementations of the second aspect described above.

In an eighth aspect, the application provides a computer program product for, when run on a computer, causing the computer to perform the method of any one of the possible implementations of the first aspect.

In a ninth aspect, the application provides a computer program product for, when run on a computer, causing the computer to perform the method of any one of the possible implementations of the second aspect.

In a tenth aspect, the present application provides a chip or chip system for use in a terminal, comprising processing circuitry and interface circuitry, the interface circuitry being for receiving code instructions and for transmitting to the processing circuitry, the processing circuitry being for executing the code instructions to perform the method of any one of the possible implementations of the first aspect.

Drawings

Fig. 1 is a schematic architecture diagram of a beidou communication system 10 according to an embodiment of the present application;

Fig. 2 is a schematic diagram of a beidou communication protocol layer provided by an embodiment of the present application;

Fig. 3 is a schematic diagram of a protocol encapsulation architecture of inbound data of the beidou communication system 10 according to an embodiment of the present application;

Fig. 4 is a schematic diagram of a protocol parsing architecture of inbound data of the beidou communication system 10 according to an embodiment of the present application;

fig. 5 is a schematic diagram of a protocol encapsulation architecture of outbound data of the beidou communication system 10 according to an embodiment of the present application;

Fig. 6 is a schematic diagram of a protocol parsing architecture of outbound data of the beidou communication system 10 according to an embodiment of the present application;

fig. 7 is a schematic flow chart of a mail downloading and inquiring method in a beidou communication system provided by the embodiment of the application;

FIG. 8A is a schematic diagram of a user interface provided by an embodiment of the present application;

FIG. 8B is a schematic diagram of a user interface provided by an embodiment of the present application;

FIG. 8C is a schematic diagram of a user interface provided by an embodiment of the present application;

Fig. 8D is a schematic structural diagram of a terminal according to an embodiment of the present application;

fig. 9 is a schematic structural diagram of a communication device according to an embodiment of the present application;

fig. 10 is a schematic structural diagram of another communication device according to an embodiment of the present application;

fig. 11 is a schematic structural diagram of another communication device according to an embodiment of the present application;

fig. 12 is a schematic structural diagram of another communication device according to an embodiment of the present application.

Detailed Description

The terminology used in the following embodiments of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the specification of the present application and the appended claims, the singular forms "a," "an," "the," and "the" are intended to include the plural forms as well, unless the context clearly indicates to the contrary. It should also be understood that the term "and/or" as used in this disclosure refers to and encompasses any or all possible combinations of one or more of the listed items.

The terms "first," "second," and the like, are used below for descriptive purposes only and are not to be construed as implying or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature, and in the description of embodiments of the application, unless otherwise indicated, the meaning of "a plurality" is two or more.

The following describes a Beidou communication system 10 provided in an embodiment of the present application.

Fig. 1 shows a schematic architecture diagram of a beidou communication system 10 in an embodiment of the present application.

As shown in fig. 1, in the beidou communication system 10, the beidou communication system 10 may include a terminal 100, a beidou short message satellite 21, a beidou network device 200, and a short message center (short MESSAGE SERVICE CENTER, SMSC) 41.

The terminal 100 is in the beidou network, that is, the beidou communication module in the terminal 100 is turned on, and the terminal 100 does not reside in the cellular network. Terminal 100 may query, via Beidou network device 200, one or more terminals residing in the cellular network (e.g., terminal 300 shown in FIG. 1) for letters sent to terminal 100.

Specifically, the terminal 100 may transmit a letter download query request to the north-fighting network device 200 for querying the north-fighting network device 200 for letters transmitted to the terminal 100 by other terminals, and download the letters. Based on the mail downloading query request, the Beidou network device 200 can query the short message center 41 for the mails sent by other terminals to the terminal 100. Then, the beidou network device 200 may reply to the terminal 100 with the query result, that is, the specific letter content or no letter.

The beidou network device 200 may include a beidou ground receiving station 31, a signal receiving processing device 32, a signal processing center 33, a beidou ground transmitting station 35, a signal sending processing device 36, an operation control center 37, and a beidou short message fusion communication platform 34.

In some embodiments, the signal processing center 33 and the operation control center 37 may be referred to as a Beidou center station. In other embodiments, the signal receiving processing device, the signal processing center 33, the signal sending processing device 36, and the operation control center 37 may be referred to as a beidou center station.

Illustratively, the beidou ground receiving station 31 may receive a mail downloading inquiry request sent by the terminal 100 forwarded by the beidou short message satellite 21. The beidou ground receiving station 31 can send the mail downloading inquiry request to the signal receiving processing device 32, and then the signal receiving processing device 32 can send the message to the signal processing center 33. The signal processing center 33 and the beidou short message fusion communication platform 34 can analyze the mail downloading query request forwarded by the beidou short message satellite 21 according to the protocol, and forward the content of the analyzed mail downloading query request to the short message center (SMSC) 41. The short message center 41 can search for letters sent from other target terminals to the terminal 100 according to the contents of the letter request.

In some examples, terminal 100 may also send data to terminal 300 through Beidou network device 200.

The Beidou network equipment 200 can send data to the terminal 100 through the Beidou short message satellite 21. For example, the terminal 100 queries letters sent to the terminal 100 by other terminals through the beidou network, and the beidou network device 200 may return a letter downloading query result to the terminal 100. Specifically, the operation control center 37 may send the letter download query result to the signal sending processing device 36, and then the signal sending processing device 36 may send the letter download query result to the beidou ground emission station 35, where the beidou ground emission station 35 sends the letter download query result to the beidou short message satellite 21, and sends the letter download query result to the terminal 100 after relaying via the beidou short message satellite 21. The mail download inquiry results in the operation control center 37 may also be obtained from the signal processing center 33.

Here, the beidou ground transmitter station 35 and the beidou ground receiver station 31 may be composed of one or more devices having a transmitting function and one or more devices having a receiving function, respectively, or may be one or more devices having a transmitting function and a receiving function, which are not limited herein.

In this way, even if the terminal 100 is under the beidou network and does not reside in the cellular network, for example, if the terminal 100 is in an area without coverage of the cellular network, the terminal 100 may query whether there is a terminal under the cellular network that transmits a letter to the terminal 100, and may acquire contents of letters transmitted to the terminal 100 by terminals under other cellular networks.

In the embodiment of the present application, data, such as a message, or a short message, a mail, or the like, transmitted to the terminal 100 is referred to as a letter. In particular, a letter may refer to a short message sent by a user a (e.g., terminal 100 shown in fig. 1) to a user a in a webless state (i.e., not residing in a cellular network, nor connected to Wi-Fi) received by other terminals (e.g., terminal 300 shown in fig. 1). The letter download query refers to: the user sends a letter download inquiry message to the beidou network device 200, so as to obtain the content of the letter sent to the terminal 100 by the target terminal under the cellular network. The Beidou short message fusion communication platform 34 in the Beidou network device 200 receives the mail downloading query message. The mail downloading inquiry message carries inquiry information which indicates the number information of the short message sender which needs to be inquired by the user. The letter downloading query result refers to that the terminal 100 receives the content of the letter returned by the beidou network device 200 or none (i.e. the target terminal does not send the letter to the terminal 100). The letter result is the content of the letter in the particular letter box. For example, the user of the terminal 100 inquires whether a parent has a letter sent to him, and the returned letter download inquiry result is the content of the letter sent by his parent (e.g. "you are safe to home").

Fig. 2 shows a schematic diagram of a beidou communication protocol layer of the beidou communication system 10 in the embodiment of the present application.

As shown in fig. 2, the beidou communication protocol layer may include an application (application layer protocol, APP) layer, a message data convergence (MESSAGE DATA convergence protocol, MDCP) layer, a Satellite Link Control (SLC) layer, and a physical (PHYSICAL LAYER) layer.

The beidou ground receiving station 31 and the beidou ground transmitting station 35 can be used for processing functions of the beidou network equipment 200 on data at the PHY layer. The signal receiving processing device 32, the signal sending processing device 36, the signal processing center 33, and the operation control center 37 may be used for processing data in the SLC layer and the MDCP layer by the beidou network device 200. The Beidou short message fusion communication platform 34 can be used for processing data at an APP layer.

Only special terminals can receive short messages (hereinafter referred to as letters) forwarded by Beidou satellites in a webless state at present. The specific process is that when the special terminal captures and tracks the Beidou signal, the start report is actively initiated, after the short message receiving and transmitting processing system station receives the message, if the buffer storage message (hereafter called letters) of the user exists, all letters of the user are directly issued, and according to receipt of the user (feedback information aiming at the case of receiving letters), the Beidou network equipment 200 decides whether to delete the buffer storage letters. The cached letters are communicated and managed through a special server built by the Beidou system, no cellular operator network element directly participates in management, and the application range is limited.

Aiming at the fact that a public civil terminal mailbox mechanism of Beidou satellite short messages is still blank at present, the embodiment of the application carries out brand new design on a data transmission protocol in a Beidou communication system and mainly comprises a mail downloading and inquiring part.

In an embodiment of the present application, the data transmitted by the terminal 100 to the north fight network device 200 may be referred to as inbound data, and the data transmitted by the terminal 100 to the north fight network device 200 may be referred to as inbound data. The data sent by the beidou network device 200 to the terminal 100 may be referred to as outbound data, and the data sent by the beidou network device 200 to the terminal 100 may be referred to as outbound data.

The following describes a process of packaging a mail download inquiry request by the terminal 100 when the terminal 100 transmits the mail download inquiry request to the north-bucket network device 200. And when the Beidou network equipment 200 receives the mail downloading query request, analyzing the mail downloading query request by the Beidou network equipment 200.

The following describes a protocol encapsulation architecture for inbound data of the beidou communication system 10 provided in the embodiment of the present application.

Fig. 3 illustrates a protocol encapsulation architecture diagram of inbound data of the beidou communication system 10 according to an embodiment of the present application.

As shown in fig. 3, the beidou messaging protocol layer on the terminal 100 may be divided into an application layer (application layer protocol, APP), a message data convergence layer (MESSAGE DATA convergence protocol, MDCP), a satellite link control layer (SLC) and a physical layer (PHYSICAL LAYER protocol, PHY).

When the terminal 100 sends data to the beidou network device 200, the workflow of the beidou message transmission protocol on the terminal 100 may be as follows:

At the APP layer, the terminal 100 may encapsulate the original data (e.g., a letter download query request) into an application layer message, and then the terminal 100 may send the application layer message to the MDCP layer through an interlayer interface. The format of the application layer message will be described in detail below, and will not be described in detail here.

In the MDCP layer, the terminal 100 may acquire an application layer packet sent by the APP layer through an interlayer interface, and use the application layer packet as an MDCP service data unit (servicedataunit, SDU). At the MDCP layer, the terminal 100 may add padding data (padding) to a designated length at the end of the MDCP SDU and add a redundant length indication field at the head of the MDCP SDU. The redundant length indication field may be used to indicate the length of the padding data. The terminal 100 may split the padding data and the MDCP SDU after adding the redundant length indication field into one or more MDCP segment data (m_ segement) of fixed length, and add a subsequent indication field to the header of each MDCP segment data, to obtain a MDCP protocol data unit (protocoldataunit, PDU), i.e. the MDCP PDU includes m_ segement and the subsequent indication field. Wherein the subsequent indication field may be used to indicate that the current MDCP PDU is a starting MDCP PDU or an intermediate MDCP PDU or a last MDCP PDU of the plurality of MDCP PDUs that are consecutively transmitted; or a separately transmitted MDCP PDU.

In the SLC layer, the terminal 100 may acquire the MDCP PDU delivered from the MDCP layer as the SLC SDU through the interlayer interface. At the SLC layer, the terminal 100 may segment the SLC SDU into one or more (up to 4) SLC segment data (s_ segement) of a fixed length, and add frame header information at each s_ segement header to obtain SLC PDUs. The frame header information includes a service data unit alternation indication (SERVICE DATA unit alternated Indicator, SAI) field, a total number of frames field, and a frame number field.

The SAI field may be used to indicate whether the SLC PDU belongs to an undelivered SLC SDU.

The total number of frames field may be used to indicate the total number of SLC PDUs included in the SLC SDU to which the SLC PDU belongs.

A frame sequence number field, which may be used to indicate the sequence number of the SLC PDU in the SLC SDU to which it belongs.

At the PHY layer, the terminal 100 may obtain, through an interlayer interface, an SLC PDU issued by the SLC layer as a code block (code block) of the PHY layer, and add a synchronization header to the header of the code block, and add a check bit field to the tail of the code block. In the beidou communication system 10, a cyclic redundancy check (cyclic redundancy check, CRC) may be used to check the encoded block, so that the check bit field may include a CRC code. The terminal 100 may encode (e.g., pole encode) the code block and the check bit field to obtain encoded data (encoded data), and insert a pilot into the encoded data to obtain pilot encoded data (pilot+data). Then, the terminal 100 sequentially modulates the synchronization header and the pilot coded data by the underlying hardware to obtain modulated data. The terminal 100 may spread the modulated data to obtain spread modulated data. The terminal 100 may send the spread spectrum modulation data to the beidou short message satellite 21, and relay the spread spectrum modulation data to the beidou network device 200 via the beidou short message satellite 21.

The following describes a protocol parsing architecture for inbound data of the beidou communication system 10 provided in the embodiment of the present application.

Fig. 4 is a schematic diagram of a protocol parsing architecture of inbound data of the beidou communication system 10 according to an embodiment of the present disclosure.

As shown in fig. 4, the beidou short message transmission protocol layer of the beidou network device 200 may be divided into an application layer (application layer protocol, APP), a message data convergence layer (MESSAGE DATA convergence protocol, MDCP), a satellite link control layer (SATELLITE LINK control protocol, SLC) and a physical layer (PHYSICAL LAYER protocol, PHY). The beidou network device 200 may include a beidou ground receiving station 31, a signal receiving processing device 32, a signal processing center 33, a beidou ground transmitting station 35, a signal sending processing device 36, an operation control center 37, and a beidou short message fusion communication platform 34.

When the beidou network device 200 receives the data sent by the terminal 100, the workflow of the beidou short message transmission protocol layer of the beidou network device 200 may be as follows:

At the PHY layer, the beidou network device 200 may acquire the modulated and spread pilot coded data sent by the terminal 100. The Beidou network device 200 can despread the received spread modulation data (spread+modulated data) to obtain modulated data (modulated data). The Beidou network device 200 may then demodulate the modulated data to obtain pilot coded data (pilot+data). Then, the beidou network device 200 removes pilot information in the pilot coded data to obtain coded data (code data). Then, the beidou network device 200 may decode the encoded data and verify the integrity of a code block (code block) through the check data in the check bit field. If the data is complete, the Beidou network device 200 can extract a code block (code block), and present the code block to the SLC layer through an interlayer interface to serve as an SLC PDU of the SLC layer.

In the SLC layer, the beidou network device 200 may splice SLC PDUs belonging to the same SLC SDU into one SLC SDU based on frame header information of the SLC PDUs. The beidou network device 200 may present SLC SDUs to the MDCP layer through the inter-layer interface, as MDCP PDUs of the MDCP layer.

In the MDCP layer, the beidou network device 200 may splice all MDCP PDUs belonging to the same MDCP SDU into one MDCP SDU. The beidou network equipment 200 can present the MDCP SDU to the APP layer through the interlayer interface, and the MDCP SDU is used as an application layer message received by the APP layer.

At the APP layer, the beidou network device 200 may decrypt and decompress the application layer packet based on the header of the application layer packet to obtain the original data. The original data may be a letter download query request.

In the embodiment of the present application, the protocol processing procedure is merely an example, and the specific operation of the protocol processing is not limited in the present application.

After receiving the mail downloading query request sent by the terminal 100, the Beidou network equipment 200 may reply to the terminal 100 with the mail downloading query result. The following describes a process of packaging the letter download query result by the beidou network device 200 when the beidou network device 200 sends the letter download query result to the terminal 100. And when the terminal 100 receives the letter download inquiry result, the terminal 100 analyzes the letter download inquiry result.

The protocol encapsulation architecture of outbound data of the beidou communication system 10 provided in the embodiment of the present application is described below.

Fig. 5 shows a schematic diagram of a protocol encapsulation architecture of outbound data of the beidou communication system 10 according to an embodiment of the present application.

As shown in fig. 5, the beidou short message transmission protocol layer of the beidou network device 200 may be divided into an application layer (application layer protocol, APP), a message data convergence layer (MESSAGE DATA convergence protocol, MDCP), a satellite link control layer (SATELLITE LINK control protocol, SLC) and a physical layer (PHYSICAL LAYER protocol, PHY). The beidou network device 200 may include a beidou ground receiving station 31, a signal receiving processing device 32, a signal processing center 33, a beidou ground transmitting station 35, a signal sending processing device 36, an operation control center 37, and a beidou short message fusion communication platform 34.

When the beidou network device 200 sends data to the terminal 100, the workflow of the beidou short message transmission protocol in the beidou network device 200 may be as follows:

At the APP layer, the beidou network device 200 may encapsulate raw data (e.g., a letter download query result) into an application layer packet. Then, the beidou network device 200 may send the application layer message to the MDCP layer through the interlayer interface. The format of the application layer message will be described in detail below, and will not be described in detail here.

Optionally, in one possible implementation manner, the beidou network device 200 segments the MDCP SDU into a plurality of MDCP PDUs in the MDCP layer, and the beidou network device 200 may transmit the plurality of MDCP PDUs to the SLC layer of the beidou network device 200 together.

In the MDCP layer, the beidou network device 200 may acquire an application layer packet sent by the APP layer through an interlayer interface, and use the application layer packet as an MDCP SDU. At the MDCP layer, the beidou network device 200 may split one MDCP SDU into one or more MDCP segment data (m_ segement) with a fixed length, and add a subsequent indication field to the header of each MDCP segment data, to obtain an MDCP PDU, that is, the MDCP PDU includes m_ segement and the subsequent indication field. Wherein the subsequent indication field may be used to indicate that the current MDCP PDU is a starting MDCP PDU or an intermediate MDCP PDU or a last MDCP PDU of the plurality of MDCP PDUs that are consecutively transmitted; or a separately transmitted MDCP PDU.

In the SLC layer, the beidou network device 200 may acquire the MDCP PDU issued by the MDCP layer through the interlayer interface, and use the MDCP PDU as the SLC SDU. At the SLC layer, the beidou network device 200 may segment the SLC SDU into one or more (at most 4) SLC segment data (s_ segement) with a fixed length, and add frame header information to each of the s_ segement header to obtain the SLC PDU.

At the PHY layer, the beidou network device 200 may acquire the SLC PDU issued by the SLC layer through an interlayer interface. The beidou network device 200 may obtain SLC PDUs of one user or a plurality of users from the SLC layer. The Beidou network device 200 may splice SLC PDUs of a plurality of users together, add a frame header (e.g., version number) of a physical frame as a code block (code block) of the PHY layer, add check bits (e.g., cyclic redundancy check (cyclic redundancy check, CRC) code) at the tail of the code block, and encode (e.g., pole encode) the code block and the CRC code, where the encoded physical frame is added with encoded data of a message branch (s2c_d branch) where a reserved segment may form a physical slot with a fixed length. The beidou network device 200 may put a plurality of SLC PDUs of one user into different physical frames respectively. Then, the beidou network device 200 composes the coded data of the s2c_d branch and the pilot information of the pilot branch (s2c_p branch) into pilot coded data, that is, outbound data. The Beidou network device 200 can send the outbound data to the Beidou short message satellite 21, and relay the outbound data to the terminal 100 through the Beidou short message satellite 21.

It will be appreciated that the pilot information of the s2c_p leg is associated with the satellite beam. When the information is known at the satellite beam number, the pilot information for the s2c_p leg is also known, and decoding is not required. And the encoded data of the s2c_d branch is to be decoded.

The protocol analysis architecture of outbound data of the beidou communication system 10 provided in the embodiment of the present application is described below.

Fig. 6 shows a schematic diagram of a protocol parsing architecture of outbound data of the beidou communication system 10 according to an embodiment of the present application.

As shown in fig. 6, the beidou short message transmission protocol layer of the terminal 100 may be divided into an application layer (application layer protocol, APP), a message data convergence layer (MESSAGE DATA convergence protocol, MDCP), a satellite link control layer (SLC) and a physical layer (PHYSICAL LAYER protocol, PHY).

When receiving data sent by the beidou network device, the terminal 100 may have the following workflow of the beidou short message transmission protocol layer of the terminal 100:

At the PHY layer, the terminal 100 may obtain the modulated and spread pilot coded data sent by the beidou network device 200. The terminal 100 may despread the received spread modulation data (spread+modulated data) to obtain the modulation data (modulated data). The terminal 100 may then demodulate the modulated data to obtain pilot-encoded data (pilot+data). Then, the terminal 100 may remove pilot information in the pilot coded data to obtain coded data (code data). The terminal 100 may then decode the encoded data and verify the integrity of the code block by the check data in the check bit field. If complete, the terminal 100 may extract a code block (code block), present to the SLC layer through the inter-layer interface, and act as an SLC PDU of the SLC layer.

Here, the pilot code data is the outbound data sent by the beidou network device 200, where the outbound data is composed of code data of the s2c_d branch and pilot information of the pilot branch (s2c_p branch).

At the SLC layer, the terminal 100 may splice SLC PDUs belonging to the same SLC SDU into one SLC SDU based on frame header information of the SLC PDUs. The terminal 100 may present SLC SDUs to the MDCP layer through an inter-layer interface as MDCP PDUs of the MDCP layer.

In the MDCP layer, the terminal 100 may splice all MDCP PDUs belonging to the same MDCP SDU into one MDCP SDU. The terminal 100 may present the MDCP SDU to the APP layer through the interlayer interface, as an application layer packet received by the APP layer.

At the APP layer, the terminal 100 may decrypt and decompress the application layer packet based on the header of the application layer packet to obtain the original data.

In an embodiment of the present application, a method for downloading and querying letters in a beidou communication system is provided, where the method may include: the terminal 100 may send a letter download query request message to the north bucket network device 200, where the letter download query request message includes a service type field and a message ID field; the service type field indicates the service type of the letter download inquiry request message, and the message ID field indicates the ID of the letter that the terminal 100 last received successfully. The terminal 100 receives a letter downloading query result message sent by the Beidou network equipment 200; the mail downloading inquiry result message comprises a data format indication field and a mail file field; the data format indication field is used for how the terminal 100 parses the letter text field; the letter text field is used to indicate the content of the letter that the target terminal or terminals sent to the terminal 100. In this way, the user can also obtain the content of the letter sent by the terminal to the terminal 100 under the cellular network under the Beidou network.

In the embodiment of the present application, the terminal 100 may be referred to as a first terminal, and the target terminal may be referred to as a second terminal.

Fig. 7 is a schematic flow chart of a mail downloading query method in a beidou communication system according to an embodiment of the present application. As shown in fig. 7, the mail downloading and querying method in the beidou communication system provided by the embodiment of the application can include the following steps:

S701, the terminal 100 generates a letter download query request packet based on the user operation, where the letter download query request packet is used to download the content of the letters sent to the terminal 100 by one or more target terminals.

The terminal 100 is in the Beidou network, namely, the terminal 100 is in the scene without the cellular network and the wireless local area network, the terminal 100 does not reside in the cellular network, and the Beidou communication module in the terminal 100 is started. The terminal 100 may communicate with the beidou network device 200 through the beidou communication module. The terminal 100 may obtain, through the beidou network, the content of the letter sent by the one or more target terminals to the terminal 100. The identity of the one or more target terminals may or may not be present in the whitelist configured by the terminal 100.

The terminal 100 may be configured with a whitelist comprising the identities of the N terminals associated with the terminal 100 and the serial numbers of the identities in the whitelist. For example, the identification of the N terminals may be a mobile phone number of each of the N terminals. Optionally, the whitelist configured by the terminal 100 may be stored in the terminal 100 and the beidou network device 200 (e.g., the beidou short message fusion communication platform 34). Optionally, the whitelist configured by the terminal 100 may also be stored in a server (e.g., the short message center 41 shown in fig. 1) of an operator (e.g., chinese mobile, chinese communication, chinese telecommunication) corresponding to the identifier of the terminal 100, which is not limited by the embodiment of the present application.

It will be appreciated that in the white list, the number of identities of the N terminals may be adjustable.

In the embodiment of the present application, the identifier of the terminal may be a mobile phone number, a login number, an international mobile equipment identification (international mobile equipment identity, IMEI), an international mobile subscriber identification (international mobile subscriber identification number, IMSI), or a mobile subscriber international integrated services digital network number (mobile subscriber international INTEGRATED SERVICE DIGITAL network number, MSISDN) of the terminal. The following description will take the identification of the terminal as an example of the mobile phone.

When the user of the terminal 100 wants to acquire the content of the letter sent by the target terminal to the terminal 100, the user can click on a control of the terminal 100 for acquiring the content of the letter (or download of the letter). Based on the user clicking on the control of the terminal 100 for acquiring the content of the letter, the terminal 100 may generate a letter download query request message.

The terminal 100 may acquire the content of the letter transmitted to the terminal 100 by the next target terminal in the cellular network, or may acquire the content of the letters transmitted to the terminal 100 by a plurality of target terminals in the cellular network.

In one possible implementation, if the identity (e.g., the mobile phone number) of the target terminal a is in the white list, the user may select to obtain, in the terminal 100, the content of the letter sent by the target terminal a to the terminal 100, e.g., the user may input, in the terminal 100, the serial number of the target terminal a in the white list, or the user may also input, in the terminal 100, the mobile phone number of the target terminal a. The user may then click on a control in the terminal 100 for acquiring the letter content.

In the embodiment of the application, the target terminals marked in the white list can be called target terminals in the white list, and the target terminals not marked in the white list can be called target terminals in the non-white list.

In one possible implementation, if the identity (e.g., the mobile phone number) of the target terminal B is not in the white list, the user may select to query the terminal 100 for the content of the letter sent by the target terminal B to the terminal 100, e.g., the user may input the mobile phone number of the target terminal B in the terminal 100. The user may then click on a control in the terminal 100 for acquiring the letter content.

Further, there may be control 1, control 2, control 3 in terminal 100. Wherein control 1 may be used to download the content of letters sent by the target terminal to terminal 100 in the whitelist. Control 2 is used to download the content of the letters of the individual target terminal sending terminal 100, which is not within the white list. Control 3 is used to download the content of the correspondence sent to terminal 100 by all target terminals, including all target terminals not in the white list and all target terminals in the white list.

In one possible implementation, the format of the mail download query request message may be as shown in table 1 below.

TABLE 1

As shown in table 1 above, the mail download query request message may include a receipt indication field, a traffic type field, an encryption indication field, a compression indication field, an application layer authentication code field, a sender ID field, a message ID field. It can be understood that, in the embodiment of the present application, the specific fields and the arrangement order of the fields are not limited in the mail downloading query request message. For example, when the mail download query request message defaults to not require an application layer receipt, the mail download query request message may not include a receipt indication field.

A specific description of each field in the letter download inquiry request message shown in table 1 can be shown in table 2 below. Table 2 exemplarily shows lengths corresponding to the respective fields in table 1 and a specific description.

TABLE 2

As shown in table 2, the receipt indication field may be used to indicate whether the receiving device (e.g., the beidou network device 200) of the mail download query request message needs to reply to the application layer receipt to the terminal 100. The application layer receipt is used for indicating whether the receiving device successfully receives the mail downloading inquiry request message. The length of the response piece indication field may be 1bit. When the receipt indication field is a value D1 (e.g., 0), the receiving device, which may be used to indicate that the letter download query request message does not need to reply to the application layer receipt to the terminal 100. When the receipt indication field is a value D2 (e.g., 1), the receiving device, which may be used to indicate that the receipt download query message needs to reply to the application layer receipt to the terminal 100. It will be appreciated that the length of the receipt indication field and the specific value of the receipt indication field are not limited in this embodiment of the present application.

As shown in table 2, a service type field may be used to indicate the service type of the letter download query request message. In the beidou communication system, the service types of the messages may include general messages, mailbox services (including mailbox profile query service and letter download query service), and the like. The length of the traffic type field may be 3bits. It will be appreciated that the length of the service type field is not limited in this embodiment of the present application. As the variety of traffic types increases, the length of the fields of the traffic type may increase. The embodiment of the application takes the length of the service type field as 3bits as an example for illustration. When the service type field in the message is 000, the service type field may be used to indicate that the service type of the message is a generic message. When the service type field in the message is 001, the service type that may be used to indicate the message may be a mailbox profile query service in a mailbox service, and the mailbox profile query request message only queries the number of letters sent by the target terminal to the terminal 100 in the whitelist. When the service type field is 010, the service type of the message may be used to indicate that the service type of the message is a mailbox profile query service in a mailbox service, specifically, to query the number of letters sent to the terminal 100 by all target terminals (including all target terminals in a non-whitelist and all target terminals in a whitelist). When the service type field in the message is 011, the service type of the message may be used to indicate that the service type of the message is a mailbox profile query service in a mailbox service, and specifically may be used to query the number of letters sent to the terminal 100 by the target terminal in a separate non-white list. When the service type field in the message is 100, the service type of the message may be used to indicate that the service type of the message is a letter download service in a mailbox service, and specifically may be used to obtain the content of a letter sent by the target terminal to the terminal 100 in a white list. When the service type field in the message is 101, the service type of the message may be used to indicate that the service type of the message is a letter download service in a mailbox service, and specifically may be that letters sent to the terminal user by all target terminals (including all target terminals in a non-whitelist and all target terminals in a whitelist) are acquired. When the service type field in the message is 110, the service type of the message may be used to indicate that the service type of the message is a letter download service in a mailbox service, and specifically may be used to obtain a letter sent to the terminal 100 by a separate non-whitelist target terminal. "111" is a reserved field.

In the embodiment of the present application, taking the service type shown in table 2 as an example, when the letter download query request packet is used to obtain the content of the letter sent from the target terminal to the terminal in the white list, the service type field in the letter download query request packet may be 100. When the letter download query request packet is used to download the contents of letters sent by all target terminals to the terminal 100, the service type field in the letter download query request packet may be 101. When the letter download query request packet is used to download the content of a letter sent to the terminal 100 by the target terminal in a separate non-whitelist, the service type field in the letter download query request packet may be 110.

In one possible implementation, when the service type of the mail download query request message is to download the content of the mail that all target terminals send to the terminal 100, the mail download query request message may not include the sender ID field.

As shown in table 2, an encryption indication field may be used to indicate whether the letter download inquiry request message is encrypted. Illustratively, the encryption indication field may be 2 bits in length. When the encryption indication field is a value D3 (e.g., 00), the letter download inquiry request message is indicated as not encrypted. It may be appreciated that the length of the encryption indication field and the specific value of the encryption indication field are not limited in the embodiments of the present application.

As shown in table 2, a compression indication field may be used to indicate whether the letter download inquiry request message is compressed. Illustratively, the length of the compression indication field may be 2 bits. When the encryption indication field is a value D4 (e.g., 00), the letter download inquiry request message is indicated to be uncompressed. It can be understood that the length of the compression indication field and the specific value of the compression indication field are not limited in the embodiment of the present application.

As shown in table 2, the application layer authentication code field may be used for authentication of the application layer. The application layer authentication code field may be, for example, 16 bits in length. It will be appreciated that the length of the application layer authentication code field is not limited in the embodiments of the present application.

As shown in table 2, the sender ID field may be used to indicate the identity of the target terminal for which the terminal 100 is to obtain the content of the letter sent to the terminal 100. If the target terminal is in the whitelist configured by the terminal 100, the sender ID field is a whitelist bitmap. If the target terminal is not in the whitelist configured by terminal 100, then the sender ID field is an identification of the target terminal (e.g., a cell phone number).

The white list contains the identifiers of the N target terminals, and then the length of the bitmap of the white list may be Nbit. For example, if the white list includes the identities of 10 target terminals, the length of the white list bitmap may be 10 bits. In the embodiment of the application, N is an integer, and the specific value of N is not limited. The following description will be given by taking N equal to 10 as an example.

Illustratively, the whitelist configured in the terminal 100 may be as shown in table 3 below.

TABLE 3 Table 3

As shown in table 3, the whitelist configured by the terminal 100 may include the identifiers of the 10 target terminals and the serial numbers corresponding to the 10 target terminals, respectively. It will be appreciated that the whitelists set by different users may be different, and the whitelist shown in table 3 is only an example, and the identifier and serial number of a specific terminal in the whitelist are not limited in the embodiment of the present application.

Illustratively, the whitelist may be as shown in table 4 or table 5 below, taking Bai Mingshan as an example shown in table 3.

TABLE 4 Table 4

TABLE 5

As shown in table 4, the whitelist bitmap may take up 10 bits, where the identifier of each target terminal in the whitelist takes up 1 bit. In one possible implementation, the identifier of the target terminal with sequence number 1 in the white list may occupy the highest bit (MSB) of the 10 bits, i.e. bit9. The identity of the target terminal with sequence number 10 in the white list may then occupy the lowest bit (leastsignificantbit, LSB) of the 10 bits, i.e. bit0. The identifier of the target terminal with the sequence number of 2 in the white list may occupy bit8 in 10 bits. The identifier of the target terminal with the sequence number of 3 in the white list may occupy bit7 in 10 bits. The identifier of the target terminal with the sequence number of 4 in the white list may occupy bit6 in 10 bits. The identifier of the target terminal with the sequence number of 5 in the white list may occupy bit5 in 10 bits. The identifier of the target terminal with the sequence number of 6 in the white list may occupy bit4 in 10 bits. The identifier of the target terminal with the sequence number of 7 in the white list may occupy bit3 in 10 bits. The identifier of the target terminal with the sequence number of 8 in the white list may occupy bit2 in 10 bits. The identifier of the target terminal with the sequence number of 9 in the white list may occupy bit1 in 10 bits. For example, if the user wants to obtain the content of the letter sent to the terminal 100 by the target terminal with the number 1 in the white list, the white list bitmap filled in the sender ID field by the terminal 100 may be "1000000000".

Alternatively, in one possible implementation, as shown in table 5, the identifier of the target terminal with the sequence number 10 in the whitelist may occupy the MSB in 10 bits, i.e. bit9. Then, the identifier of the target terminal with the serial number of 1 in the white list may occupy the LSB in 10 bits, i.e. bit0. The identifier of the target terminal with the sequence number 9 in the white list may occupy bit8 in 10 bits. The identifier of the target terminal with the sequence number of 8 in the white list may occupy bit7 in 10 bits. The identifier of the target terminal with the sequence number of 7 in the white list may occupy bit6 in 10 bits. The identifier of the target terminal with the sequence number of 6 in the white list may occupy bit5 in 10 bits. The identifier of the target terminal with the sequence number of 5 in the white list may occupy bit4 in 10 bits. The identifier of the target terminal with the sequence number of 4 in the white list may occupy bit3 in 10 bits. The identifier of the target terminal with the sequence number of 3 in the white list may occupy bit2 in 10 bits. The identifier of the target terminal with the sequence number of 2 in the white list may occupy bit1 in 10 bits. For example, if the user wants to obtain the content of the letter sent to the terminal 100 by the target terminal with the number 1 in the white list, the white list bitmap filled in the sender ID field by the terminal 100 may be "0000000001".

If the user inquires about the content of the letter sent to the terminal 100 by the target terminal in the non-white list, the sender ID field contains the mobile phone number of the target terminal, and the length of the sender ID field may be 44 bits or 34 bits, which is not limited herein. For example, the user of the terminal 100 wants to query the content of the letter sent to the terminal 100 by the target terminal with the phone number "158 xxxxx". If the target terminal is not in the white list of the terminal 100, the terminal 100 may fill the sender ID field with binary data encoded into 44 bits by the mobile phone number "158 xxxxxxx" of the target terminal. Alternatively, the terminal 100 may also fill the sender ID field with binary data encoded into 34 bits after compressing the mobile phone number "158 xxxxxxx" of the target terminal.

As shown in table 2, the message ID field may be used to indicate the ID of the first letter that the terminal 100 last received successfully. The last time the terminal 100 receives the successful first letter means that before the user clicks the control for acquiring the letter content, the receiving time of the letter received by the terminal 100 and clicking the letter with the shortest time interval between the control for acquiring the letter content. The first letter is sent to the first terminal by the target terminal, specifically, the target terminal sends the first letter to the short message center 41 first, and then, when the terminal 100 side initiates the downloading of the letter, the beidou network device 200 may acquire the first letter from the short message center 41 and send the first letter to the terminal 100.

Optionally, after the terminal 100 receives the first letter, the beidou network device 200 may receive a notification that the terminal 100 successfully downloads the first letter. Upon receiving the notification of successful downloading of the first letter, the Beidou network device may notify the short message center 41 to delete the content of the first letter. The short message center may have the ID and the sending time of the first letter reserved. The transmission time of the first letter may refer to a time when the target terminal transmits the first letter, that is, a time when the target terminal transmits the first letter to the short message center 41.

Alternatively, if the terminal 100 sends a mail download inquiry request message to the north funnel network device 200 for the first time, i.e., the terminal 100 has not downloaded a mail before, the message ID field may be an initial value (e.g., 0). When the message ID field is an initial value, the message ID field indicates that the letter download inquiry request message is used to download the contents of a letter transmitted from the one or more target terminals to the terminal 100, starting from the first letter stored in the short message center 41 and transmitted to the terminal 100.

It will be appreciated that the ID of the first letter is numbered by the beidou network device 200 when sending the first letter to the terminal 100.

S702, the terminal 100 segments the mail download inquiry request message into one or more satellite link control SLC layer protocol data units PDU1.

Specifically, the terminal 100 may send a mail download query request message to the MDCP layer through an interlayer interface. The terminal 100 may segment the letter download inquiry request message into one or more MDCP PDUs at the MDCP layer. The terminal 100 then issues one or more MDCP PDUs to the SLC layer. The terminal 100 may segment each MDCP PDU into one or more SLC PDU1 at the SLC layer. At the SLC layer, the terminal 100 may fill in a user ID field in the header of each SLC PDU1 with an identification of the terminal 100 (e.g., a cell phone number of the terminal 100). Reference may be made specifically to the description of the inbound data encapsulation process in the Beidou communication system 10 of fig. 3, and details are not repeated here.

It will be appreciated that the number of fragments of the letter download inquiry request message into SLC PDU1 depends on the data length of the letter download inquiry request message and the maximum data carrying capacity of one SLC PDU1. For example, when the data length of the letter download inquiry request message is multiple times the maximum data carrying capacity of one SLC PDU1, the terminal 100 may segment the letter download inquiry request message into a plurality of SLC PDU1. When the data length of the letter download inquiry request message is equal to or less than the maximum data carrying capacity of one SLC PDU1, the terminal 100 may divide the letter download inquiry request message into one SLC PDU1. The embodiment of the present application does not limit the specific number of SLC PDU1 obtained by segmenting the mail download inquiry request message by the terminal 100.

Illustratively, as shown in table 1, the receipt indication field in the mail download inquiry request message may be 1bit, the service type field may be 3 bits, the encryption indication field may be 2 bits, the compression indication field may be 2 bits, the application layer authentication code field may be 16 bits, the sender ID field may be 10 bits or 34 bits, the message ID may be 4 bits, and the data length of the mail download inquiry request message may be 38 bits or 62 bits. If the maximum data carrying capacity of one SLC PDU1 in the terminal 100 is 128 bits, the letter download inquiry request message may be divided into one SLC PDU1.

S703, the terminal 100 transmits one or more SLC PDU1 to the north bucket network device 200.

The terminal 100 may transmit one or more SLC PDU1 to the beidou network device 200. Specifically, the terminal 100 may send one SLC PDU1, and send a second SLC PDU1 to the north bucket network device 200 after receiving the SLC PDU1 successfully received by the beidou network device 200. Alternatively, the terminal 100 may sequentially send one or more SLC PDU1 to the beidou network device 200, and the beidou network device 200 replies to the terminal 100 that the SLC PDU1 is successfully received after receiving all the SLC PDU1.

S704, the beidou network device 200 receives one or more SLC PDU1.

The Beidou network device 200 may receive one or more SLC PDU1.

In one possible implementation, after the beidou network device 200 registers one or more SLC PDU1, the terminal 100 is replied to the registered one or more SLC PDU1. When the terminal 100 has transmitted one or more SLC PDU1, but the beidou network device 200 does not receive one or more SLC PDU1, the beidou network device 200 may transmit an Acknowledgement (ACK) frame to the terminal 100, where the ACK frame is used to indicate that the beidou network device 200 does not receive the SLC PDU1. The terminal 100 may again transmit SLC PDU1 to the north bucket network device 200, which is not registered by the Beidou network device 200.

Further, the beidou network device 200 may parse the identifier (for example, the mobile phone number 138 xxxxx) of the terminal 100 in the user ID field in the frame header of each SLC PDU1 at the SLC layer.

S705, the Beidou network equipment 200 spells one or more SLC PDU1 into a letter download inquiry request message.

Specifically, the beidou network device 200 may splice one or more SLC PDU1 into one or more SLC SDUs at the SLC layer. Then, the beidou network device 200 uploads one or more SLC SDUs to the MDCP layer as one or more MDCP PDUs of the MDCP layer. Then, the beidou network device 200 may splice one or more MDCP PDUs into a MDCP SDU at the MDCP layer. Then, the beidou network device 200 may upload the MDCP SDU to the APP layer as a mail downloading query request message. Reference may be made to the description of the decapsulation procedure of inbound data for the beidou communication system in fig. 4, which is not repeated here.

S706, the Beidou network equipment 200 generates a letter downloading query result message based on the letter downloading query request message, wherein the letter downloading query result message is used for indicating the content of a letter sent to the terminal 100 by the target terminal.

The beidou network device 200 may query the short message center 41 for the content of the letter sent to the terminal 100 based on the letter download query request message. The short message center 41 may store the content of the letter sent from the target terminal to the terminal 100, or may store no letter sent from the target terminal to the terminal 100 (i.e., no letter is sent from the target terminal to the terminal 100). Then, the beidou network device 200 may generate a letter download query result message from the query result, where the letter download query result message is used to indicate the content of a letter sent by the target terminal to the terminal 100 or indicate that the target terminal does not send a letter to the terminal 100.

Specifically, in one possible implementation, when the letter download query request packet indicates to query the content of the letters sent to the terminal 100 by all the target terminals, the beidou network device 200 may parse the ID (e.g., "1") of the first letter received last by the terminal 100 according to the identification of the terminal 100 parsed from the SLC PDU1 (e.g., the mobile phone number 138xxxxxxx of the terminal 100) and the message ID field in the letter download query request packet. The Beidou network device 200 can acquire the content of letters sent to the mobile phone number 138xxxxx by all target terminals according to the identification of the terminal 100. The Beidou network device 200 may number the letters when sending the letters to the terminal 100 (in the embodiment of the present application, the number obtained by encoding the letters by the Beidou network device 200 may be referred to as the ID of the letters). Specifically, the beidou network device 200 may sequentially number the letters sent to the terminal 100 from the ID of the first letter, to obtain the ID of each letter. For example, if the ID of the first letter is 1, the ID of the first letter that the beidou network device 200 sends to the terminal 100 this time is 2, and the ID of the second letter that is sent to the terminal 100 is 3.

Further, when the beidou network device 200 receives that the ID of the first letter indicated by the message ID field in the letter download query request message sent by the terminal 100 is 1, the beidou network device 200 can learn that the terminal 100 has successfully received the letter with the ID of 1 according to the ID of the first letter indicated in the message ID field. If the Beidou network device 200 further stores a letter with an ID of 1, the Beidou network device 200 may delete the letter with the ID of 1. In this way, the Beidou network device 200 can be prevented from sending the letter with the ID of 1 to the terminal 100 again.

Optionally, in another possible implementation, when the letter download query request packet indicates to obtain the content of the letter sent by the target terminal to the terminal 100 in the white list, the beidou network device 200 may parse the identifier of the terminal 100 (for example, the mobile phone number 138xxxxxxx of the terminal 100) from the SLC PDU 1. The beidou network device 200 may also parse the identifier of the target terminal in the whitelist (for example, the mobile phone number "13xxxxx 0") from the whitelist bitmap in the sender ID field of the mail downloading query request message, and parse the ID (for example, "1") of the first mail received last time by the terminal 100 from the message ID field. The Beidou network device 200 can obtain the content of letters sent to the mobile phone number 138xxxxx by the mobile phone number 13xxxxx 0 in the white list according to the identification of the terminal 100 and the identification of the target terminal in the white list. The Beidou network equipment 200 numbers the letters sent to the mobile phone number 138xxxxx by the mobile phone number 13xxxxx 0 in the white list based on the ID of the first letter, and obtains the ID of the letter. For example, if the ID of the first letter is 1, the ID of the letter sent to the mobile phone number 138xxxxx by the mobile phone number 13xxxxx 0 may be 2.

Optionally, in another possible implementation, when the letter download query message indicates that the content of the letter sent by the target terminal to the terminal 100 in the single non-whitelist is acquired, the beidou network device 200 may parse the identity of the terminal 100 (for example, the mobile phone number 138xxxxxxx of the terminal 100) from the SLC PDU 1. The beidou network device 200 may also parse the ID of the letter received last time by the terminal 100 (e.g., "1") from the message ID field, and parse the ID of the letter (e.g., "158 xxxxxxxx 0") from the sender ID field of the letter download query request message, and the identification of the target terminal in the non-whitelist. The beidou network device 200 may obtain, according to the identifier of the terminal 100, the identifier of the target terminal in the whitelist, after obtaining the letter sending time with the ID of the letter being a1 in the short message center 41, the content of the letter sent to the mobile phone number 138xxxxxxxx by the mobile phone number 158 xxxxxxxx 0 in the non-whitelist. The Beidou network equipment 200 numbers letters sent to the mobile phone number 138xxxxx by the mobile phone number 158xxxxx 0 in the non-white list based on the ID of the first letter, and obtains the ID of the letter. For example, if the ID of the first letter is 1, the ID of the letter sent to the phone number 138xxxxxxx by the phone number 158xxxxxxx0 in the non-whitelist may be 2.

It will be appreciated that the short message center 41 may have stored therein the content of letters sent by different terminals to the terminal 100. Illustratively, the format of the content of the letter transmitted to the terminal 100 by the different terminals stored in the short message center 41 may be as shown in table 6A below.

TABLE 6A

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As shown in table 6A, the short message center 41 may store the recipients of different mobile phone numbers, and the sending time of the letter. For example, the receiving party is a mobile phone number 138xxxxx (i.e., the mobile phone number of the terminal 100 described above), and the sending party in the whitelist corresponding to the mobile phone number 138xxxxx (e.g., mobile phone number 13xxxxx 0, mobile phone number 13xxxxx 1, etc.), the sending party in the non-whitelist (e.g., mobile phone number 158xxxxxx 0, mobile phone number 158xxxxx 1, etc.), and the sending time of the letter, the content of the letter, etc. The receiving party is a sender in a white list corresponding to the mobile phone number 136xxxxx (for example, mobile phone number 159xxxxx 0, mobile phone number 159xxxxx 1, etc.), a sender in a non-white list (for example, mobile phone number 166xxxxx 0, mobile phone number 166xxxxx 1, etc.), and a letter sending time, a content of a letter, etc. corresponding to the mobile phone number 136 xxxxx. The following will specifically describe an example in which the receiver is a mobile phone number "138 xxxxxxx".

Specifically, as shown in table 6A, 13xxxxxxxx0 is in a whitelist corresponding to the mobile phone number 138 xxxxxxxx. The mobile phone number 13xxxxxxx 0 is sent to a letter of the mobile phone number 138xxxxx in 2021/09/01 08:00:00, and the content of the letter is "tomorrow". 13xxxxxxx 0 sends letters to the phone number 138xxxxx at 2021/09/01 18:30:05, the content of the letters being "tomorrow eat together".

Specifically, as shown in table 6A, 13xxxxxxxx1 is in a whitelist corresponding to the mobile phone number 138 xxxxxxxx. The mobile phone number 13xxxxxxx 1 is sent to a letter of the mobile phone number 138xxxxx in 2021/09/01 14:30:05, and the content of the letter can be "safe after going home". 13xxxxxxx 1 sends letters to the phone number 138xxxxx at "2021/09/01 19:35:40", the content of which may be "you are home.

Specifically, as shown in table 6A, 158 xxxxxxxx 0 is not within the whitelist corresponding to the cell phone number 138 xxxxxxxx. The cell phone number 158xxxxxx 0 is sent to the letter of cell phone number 138xxxxxx at "2021/09/0219:00:00", the content of which may be "where you are". 158 xxxxxxxx 1 is not within the whitelist corresponding to the cell phone number 138 xxxxxxxx. The mobile phone number 158xxxxx 1 is sent to a letter of the mobile phone number 138xxxxx in 2021/09/0219:05:10, and the content of the letter can be "call me after seeing a short message".

It should be understood that table 6A is merely an example, and the format of the letters and the specific contents of the letters sent to the terminal 100 by the different target terminals stored in the short message center 41 in the embodiment of the present application are not limited.

Alternatively, the short message center 41 may not know the white list information of the terminal 100, that is, the white list corresponding to the terminal 100 is not stored in the short message center 41, but only the short messages sent to the terminal 100 by different terminals are cached. The short message center 41 only sends the content of the letters sent by the one or more target terminals to the beidou network equipment 200, and the beidou network equipment 200 determines whether the one or more target terminals are target terminals in the whitelist according to the saved whitelist.

In one possible implementation, after receiving the letter sent to the terminal 100, the short message center 41 sends the letter sent to the terminal 100 to the beidou network device 200 after determining that the terminal 100 is under the beidou network.

Optionally, in another possible implementation manner, when the beidou network device 200 receives the mail downloading query request message of the terminal 100, the beidou network device 200 acquires the mail sent to the terminal 100 from the short message center 41 based on the mail downloading query request message.

Further, in one possible implementation, the communications sent to the terminal 100 may be stored in the beidou network device 200. The beidou network device 200 may store the letters transmitted to the terminal 100 in the form of a queue according to the original transmission time of the letters. The queue storing letters may follow a first-in first-out principle. If the same target terminal sends multiple letters to the terminal 100, the Beidou network device 200 can send the letters with the previous original sending time to the terminal 100. And then the Beidou network equipment 200 sends the letters with the original letters after the sending time to the terminal 100.

Illustratively, the format of the content of the letter transmitted to the terminal 100 by the different terminals stored in the beidou network device 200 may be as shown in table 6B below.

TABLE 6B

As shown in table 6B, letters sent from different terminals to the terminal 100 are stored in the beidou network device 200. Specifically, the beidou network device 200 may store letters of different terminals 100 in a queue form, and arrange the letters sent to the terminals 100 by the different terminals according to the sequence of the letter sending time. The beidou network device 200 may also store an identifier (for example, a mobile phone number) of each sender transmitting letters to the terminal 100, whether the identifier of the sender is in a white list, a letter transmission time, contents of the letters, and the like. The letters stored in the beidou network device 200 may follow the principle of first-in first-out, that is, when the terminal 100 downloads a letter sent by a single target terminal, the beidou network device 200 sends the letter with the earliest letter sending time in multiple letters sent by the single target terminal to the terminal 100. And when the terminal downloads the letters sent by all the target terminals, the Beidou network equipment 200 sends the letters with earliest letter sending time in the multiple letters sent by all the target terminals to the terminal 100.

In some scenarios, the user downloads, at terminal 100, the letter dad sent to terminal 100. As shown in table 6B, two letters sent to terminal 100 by dad are the first and third letters in the queue of letters sent to terminal 100 stored by beidou network device 200 (i.e. letters with letter sending times 2021/09/01 08:00:00 and 2021/09/01 18:30:05, respectively). When the message ID field in the mail download query request message sent by the terminal 100 to the beidou network device 200 indicates that the ID of the mail that was last successfully received by the terminal 100 is 1, the beidou network device 200 may set the mail ID of the mail whose mail sending time is 2021/09/01 08:00:00 sent by dad to 2 and set the mail ID of the mail whose mail sending time is 2021/09/01 18:30:05 sent by dad to 3. Then, the beidou network device 200 first transmits the letter with the letter ID of 2 to the terminal 100. After the beidou network device 200 sends the letter with the letter ID of 2, if the beidou network device 200 receives the prompt message that the terminal 100 successfully receives the letter with the letter ID of 2, the beidou network device 200 may delete the letter with the letter ID of 2 and send the letter with the letter ID of 3 to the terminal 100. After the Beidou network equipment 200 sends the letters with the letter ID of 3, if the Beidou network equipment 200 receives a prompt message that the terminal 100 successfully receives the letters with the letter ID of 3, the Beidou network equipment 200 can delete the letters with the letter ID of 3; if the Beidou network device 200 does not receive the prompt message that the terminal 100 successfully receives the letter with the letter ID of 3, the Beidou network device 200 can continuously store the letter with the letter ID of 3 and record the letter ID of the letter.

In one possible implementation, if the beidou network device 200 does not receive the prompt message that the terminal 100 successfully receives the letter with the letter ID 2, the beidou network device 200 may continue to save the letter with the letter ID 2 and record the letter ID of the letter. And, the beidou network device 200 stops sending the letters to the terminal 100, i.e. the beidou network device 200 no longer sends letters with the letter ID of 3 to the terminal 100.

In some scenarios, after the user downloads the letter sent by dad to terminal 100 in terminal 100, the user downloads the letter sent by mom to terminal 100 in terminal 100 again. At this time, the message ID field in the letter download inquiry request message sent by the terminal 100 to the beidou network device 200 indicates that the ID of the letter successfully received last time by the terminal 100 is 3. The Beidou network device 200 can set the letter ID of the letter sent by the mother at 2021/09/01 08:00:00 to 4 and set the letter ID of the letter sent by the mother at 2021/09/01 19:35:40 to 5. Then, the beidou network device 200 transmits the letter with the letter ID of 4 to the terminal 100, and then transmits the letter with the letter ID of 5 to the terminal 100.

In some scenarios, after the user downloads the letters sent by dad to terminal 100 in terminal 100, the user downloads all the letters sent by the target terminal to terminal 100 in terminal 100 again. At this time, the message ID field in the letter download inquiry request message sent by the terminal 100 to the beidou network device 200 indicates that the ID of the letter successfully received last time by the terminal 100 is 3. If the Beidou network device 200 determines that the Beidou network device 200 stores the mail with the mail ID of 3, the Beidou network device 200 can delete the mail with the mail ID of 3. Then, the beidou network device 200 sequentially sets IDs of other letters starting from ID 4.

In this way, the Beidou network device 200 can be prevented from repeatedly sending the same letters to the terminal 100.

In some scenarios, the number of letters stored by the beidou network device 200 and sent to the terminal 100 is M, which is greater than a first threshold, where the first threshold is N, and M is greater than N. The Beidou network device 200 can set IDs of the first through N-th letters in sequence from 1, wherein the ID of the first letter is 1, the ID of the second letter is 2, …, and the N-th letter is N. The Beidou network device 200 then sets the IDs of the letters in order from 1 for the (n+1) -th to (M) -th letters. When M is greater than N and less than or equal to 2N, the letter ID of the (n+1) th letter is 1, the letter ID of the (n+2) th letter is 2, and the letter of the (…) th letter is M-N. For example, taking N as 16 and M as 17 as an example, the beidou network device 200 may set IDs of the first to sixteenth letters in order from 1, that is, the letter ID of the first letter is 1 and the letter ID of the sixteenth letter is 16. The beidou network device 200 then sets the IDs of the seventeenth letters again in order from 1, i.e. the letter ID of the seventeenth letter is 1. It will be appreciated that when the beidou network device 200 sends the seventeenth letter, the beidou network device 200 has successfully sent the first sixteen letters to the terminal 100, and the beidou network device 200 may delete the first sixteen letters.

In one possible implementation, the short message center 41, and/or the Beidou network device 200, only holds letters for a preset time. For example, if the beidou network device 200 only holds letters within three days, the beidou network device 200 deletes letters with a letter sending time of three days before three days after three days. As shown in table 6B, if the terminal 100 does not download the letter with the sending time of "2021/09/0408:00:00" in "2021/09/01 08:00:00", the beidou network device 200 deletes the letter with the sending time of "2021/09/01 08:00:00" in "2021/09/0408:00:00". When the terminal 100 performs the mail downloading query in the '2021/09/0408:00:00', the Beidou network equipment does not send the mails sent by other terminals in the '2021/09/01 08:00:00' and '2021/09/01 08:00:00' to the terminal 100. Therefore, the buffer capacity of the Beidou network equipment can be timely reduced, and the memory space of the Beidou network equipment can be timely released.

After the Beidou network device 200 queries the content of the letter sent to the terminal 100 by the target terminal in the letter download query request message from the short message center 41, the Beidou network device 200 may generate a letter download query result message based on the content of the letter.

In one possible implementation, the format of the mail download query result message may be as shown in Table 7 below.

TABLE 7

As shown in table 7 above, the mail download query result message may include a message type indication field, a mail download complete indication field, an encryption indication field, a compression indication field, an application layer authentication code field, a whitelist indication field, a sender ID field, a message original transmission time field, a message ID field, a location information indication field, a location information field, a data format field, and a mail content field. It can be understood that, in the embodiment of the present application, the specific fields and the arrangement order of the fields are not limited in the letter download query result message. For example, if the beidou network device 200 does not encrypt the mail downloading query result message, the mail downloading query result message may not include the encryption indication field.

A specific description of each field in the letter download inquiry result message shown in table 7 can be shown in table 8 below. Table 8 exemplarily shows lengths corresponding to the respective fields in table 7 and detailed descriptions.

TABLE 8

As shown in table 8, a message type indication field may be used to indicate the specific type of the letter download query result message in the mailbox service. The message type indication field may be 1bit in length. Illustratively, when the message type indication field in a message may be a value M1 (e.g., 0), it may be used to indicate that the particular traffic type of the message is a mailbox profile. When the message type indication field in the message may be a value M2 (e.g., 1), the specific service type that may be used to indicate the mail download query result message is a mail download. In the embodiment of the present application, the message type indication field in the letter download inquiry result message may be a value M2. It will be appreciated that the length and specific value of the message type indication field are not limited in this embodiment of the present application.

As shown in table 8, a letter download completion indication field may be used to indicate whether a letter is subsequently sent to the terminal 100. The length of the mail download complete indication field may be 1bit. When the letter download completion indication field is a value M3 (e.g., 1), it may be used to indicate that there is a letter to be sent to the terminal 100 in the following. When the letter download completion indication field is a value M4 (e.g., 0), it may be used to indicate that no letters are subsequently sent to the terminal 100. It will be appreciated that the length and specific value of the indication field for downloading the letter are not limited in the embodiment of the present application.

It may be appreciated that, when the terminal 100 queries the content of the letters sent to the terminal 100 by all the target terminals, the beidou network device 200 may package the content of each letter sent by each target terminal after the sending time of the first letter into a letter download query result message. Then, the beidou network device 200 sequentially transmits each letter download inquiry result message to the terminal 100. Illustratively, the letter download completion indication field in the first letter download inquiring result message sent by the beidou network device 200 is a value M3, the letter download completion indication field in the second letter download inquiring result message is a value M3, the letter download completion indication field in the N-1 th letter download inquiring result message is a value M3, and the letter download completion indication field in the last (i.e., N-th) letter download inquiring result message is a value M4.

As shown in table 8, an encryption indication field may be used to indicate whether the letter download inquiry request message is encrypted. Illustratively, the encryption indication field may be 2 bits in length. When the encryption indication field is a value D3 (e.g., 00), the letter download inquiry request message is indicated as not encrypted. It may be appreciated that the length of the encryption indication field and the specific value of the encryption indication field are not limited in the embodiments of the present application.

As shown in table 8, a compression indication field may be used to indicate whether the letter download inquiry request message is compressed. Illustratively, the length of the compression indication field may be 2 bits. When the encryption indication field is a value D4 (e.g., 00), the letter download inquiry request message is indicated to be uncompressed. It can be understood that the length of the compression indication field and the specific value of the compression indication field are not limited in the embodiment of the present application.

As shown in table 8, the application layer authentication code field may be used for authentication of the application layer. The application layer authentication code field may be, for example, 16 bits in length. It will be appreciated that the length of the application layer authentication code field is not limited in the embodiments of the present application.

As shown in table 8, a whitelist indication field may be used to instruct the terminal 100 to parse the sender ID field. The length of the whitelist indication field may be 1bit. When the whitelist indication field is a value D5 (e.g., 0), it is used to instruct the terminal 100 to parse the sender ID field by 34 bits. When the whitelist indication field is a value D6 (e.g., 1), the whitelist indication field is used to instruct the terminal 100 to parse the sender ID field according to the whitelist translation. It can be understood that the length of the whitelist indication field and the specific value of the whitelist indication field are not limited in the embodiment of the present application.

As shown in table 8, the sender ID field may be used to indicate the identity of the target terminal that sent the letter to the terminal 100. When the whitelist indication field is a value D5 (e.g., 0), the sender ID field may be an identification of a 34bit target terminal (e.g., a mobile phone number). When the whitelist indication field is a value D6 (e.g., 1), the whitelist translation field of 4 bits in the sender ID field may be a sequence number of the target terminal in the whitelist. The terminal 100 may translate the whitelist number into an identification of the target terminal. It will be appreciated that the length of the sender ID field and the specific value of the sender ID field are not limited in this embodiment of the present application.

The detailed definition of the whitelist translation field may be as shown in table 9 below, with table 9 showing specific whitelist numbers corresponding to different values of the whitelist translation field.

TABLE 9

White list translation field	Sequence numbers in white list	Identification of corresponding target terminal
			0000	1	13xxxxxxxx0
0001	2	13xxxxxxxx1
			…	…	…
1010	10	13xxxxxxxx9

As shown in table 5, the identification of 10 target terminals associated with the terminal 100 in the white list is taken as an example. When the whitelist translation field is 0000, the identifier of the target terminal with the sequence number of "1" in the whitelist may be indicated, and the identifier of the target terminal is specifically "13xxxxxxx 0". When the whitelist translation field is 0001, the identification of the target terminal with the sequence number of "2" in the whitelist may be indicated, and the identification of the whitelist may be "13xxxxx 1" specifically. When the whitelist translation field is 1010, the identifier may be used to indicate the identifier of the target terminal with the sequence number of "10" in the whitelist, and the identifier of the target terminal may be "13xxxxx 9".

As shown in table 8, the original message transmission time field may be used to indicate the original transmission time of a letter, i.e., the time when the target terminal transmitted the letter. The original message transmission time field detailed definition may be as shown in table 10.

Table 10

As shown in table 10, the original message transmission time field may be 7 bits in length. Since the carrier (i.e. the short message center 41) only caches letters within 3 days, for 72 hours, the time that the letters are cached in the carrier server is represented by 7 bits, and the terminal side can calculate the time that the letters reach the carrier server according to the value and display the time. It will be appreciated that if the operator can buffer letters longer than 72 hours, the original message transmission time field may be greater than 7 bits in length. The length of the original message sending time field is not limited in the embodiment of the application.

As shown in table 8, a letter ID field may be used to indicate the ID of the letter. The letter ID field may be 4 bits in length. It will be appreciated that the length of the letter ID field is not limited by the embodiments of the present application.

As shown in table 8, the location information indication field may be used to indicate whether the subsequent field is location information. The length of the location information indication field may be 1bit. Illustratively, when the location information indication field is 0, it may be used to indicate that the location information field is empty, i.e., that there is no subsequent location information field. When the location information indication field is 1, it may be used to indicate the subsequent 47 bits as location information. It will be appreciated that the length and specific value of the location information indicator field are not limited in this embodiment of the present application.

As shown in table 8, the location information field may be used to indicate location information of the target terminal. When the location information indication field is 0, there may be no location information field in the mail download inquiry result message. When the location information indication field is 1, 47 bits after the location information indication field are the location information of the target terminal. The length of the location information field may be 47 bits, and specifically, the location information field may be longitude and latitude information of the target terminal. It will be appreciated that the length and specific value of the location information field are not limited in this embodiment of the present application.

The detailed definition of the location information field can be as shown in table 11 below.

TABLE 11

As shown in table 11 above, the location information field may include a longitude field and a latitude field, and the length of the longitude field may be 24 bits. The length of the latitude field may be 23 bits.

The longitude field may include a sign bit field and a longitude value field. The sign bit field may be 1bit in length and the longitude value field may be 23 bits in length. The east meridian is indicated when the sign bit field is a value S1, and the west meridian is indicated when the sign bit field is a value S2. The value S1 is different from the value S2. Specifically, the value S1 may be 0 and the value S2 may be 1. Alternatively, the value S1 may be 1 and the value S2 may be 0. The longitude value field indicates a range of longitude values from 0 to 648000 in units of angle, seconds.

The latitude field may include a sign bit field and a latitude value field. The length of the sign bit field may be 1bit and the length of the latitude value field may be 22 bits. When the sign bit field is a value T1, north latitude is indicated, and when the sign bit field is a value T2, south latitude is indicated. The value T1 is different from the value T2. Specifically, the value T1 may be 0 and the value T2 may be 1. Alternatively, the value T1 may be 1 and the value T2 may be 0. The latitude value field indicates a longitude value ranging from 0 to 324000 in units of angle in seconds.

In this way, the target terminal may report its location to the terminal 100.

In some scenarios, the target terminal may also be under the beidou network, i.e. the target terminal does not reside in the cellular network, and the target terminal reports the position of the target terminal to the terminal 100 through the beidou network device 200, so that the terminal 100 may acquire the position information of the target terminal. When the user of the target terminal is in the dangerous zone or lost, the user of the terminal 100 may search for and rescue the user of the target terminal according to the location information of the target terminal.

In other scenarios, the target terminal may also be in a cellular network, and the target terminal may send location information of the target terminal to the terminal 100. The user of the terminal 100 finds the user of the target terminal as soon as possible based on the location information sent by the target terminal. Or when the terminal 100 is not far from the target terminal, but the target terminal is located at a position having cellular network coverage, the terminal 100 is located at a position having no cellular network coverage. The target terminal may then send location information to the terminal 100, and the terminal 100 may find a place covered by the cellular network as soon as possible based on the location information sent by the target terminal. In this way, the terminal 100 can also get in touch with the target terminal as soon as possible.

As shown in table 8, the data format field may be used to instruct the terminal 100 how to parse the letter content field. The length of the data format field may be 1bit. When the data format field is a value M5 (e.g., 1), it may be used to instruct the terminal 100 to parse the letter content field in a fixed text. When the data format field is a value M6 (e.g., 0), it may be used to instruct the terminal 100 to parse the letter content field in an indefinite length text. The length of the data format field and the specific value of the data format field are not limited in the embodiment of the application.

As shown in table 8, the letter content field may be used to indicate the content of the letter sent by the target terminal to the terminal 100. When the data format indication field is a value M5 (e.g., 1), the letter content field is a text of a fixed length (e.g., 5 bits). When the data format indication field is a value M6 (e.g., 0), text of indefinite length (e.g., nbit) is in the message data field. It will be appreciated that embodiments of the present application are not limited in the length of the letter content fields.

It will be appreciated that the destination terminal may send its own location information to the terminal 100 when sending a letter to the terminal 100.

Alternatively, when only the location information of the target terminal is included in the letter transmitted only to the terminal 100 by the target terminal, the location information indication field and the location information field may be included in the result of the letter download inquiry, and the data format indication field and the letter content field may not be included.

S707, the Beidou network equipment 200 segments the mail downloading query result message into one or more SLC PDU2.

Specifically, the beidou network device 200 may send the mail downloading query result message to the MDCP layer through the interlayer interface. The beidou network device 200 may segment the letter download inquiry result message into one or more MDCP PDUs at the MDCP layer. Then, the beidou network device 200 issues one or more MDCP PDUs to the SLC layer, as SLC SDUs of the SLC layer. The Beidou network device 200 may segment each SLC SDU into one or more SLC PDU2 at the SLC layer. At the SLC layer, the beidou network device 200 may fill in the user ID field in the header of each SLC PDU2 with the identity of the terminal 100 (e.g., the mobile phone number of the terminal 100). Reference may be made specifically to the description of the outbound data encapsulation process in the Beidou communication system 10 in fig. 5, and details are not repeated here.

It will be appreciated that the number of fragments of the letter download query result message into SLC PDU2 depends on the data length of the letter download query result message and the maximum data carrying capacity of one SLC PDU2. For example, when the data length of the letter download inquiry result message is multiple times of the maximum data carrying capacity of one SLC PDU2, the beidou network device 200 may segment the letter download inquiry result message into a plurality of SLC PDU2. When the data length of the letter download inquiry result message is equal to or less than the maximum data carrying capacity of one SLC PDU2, the beidou network device 200 may divide the letter download inquiry result message into one SLC PDU2. The specific number of SLC PDU2 obtained by segmenting the mail downloading inquiry result message by the beidou network equipment 200 is not limited in the embodiment of the present application.

S708, the beidou network device 200 sends one or more SLC PDU2 to the terminal 100.

The beidou network device 200 may send one or more SLC PDU2 to the terminal 100. Specifically, the beidou network device 200 may send one SLC PDU2, and send a second SLC PDU2 to the terminal 100 after receiving the SLC PDU2 successfully received by the terminal 100. Optionally, the beidou network device 200 may also sequentially send one or more SLC PDU2 to the terminal 100, and after receiving all the SLC PDU2, the terminal 100 replies to the beige network device 200 that the SLC PDU2 is successfully received. Or the terminal 100 may not reply. The embodiment of the present application is not limited thereto.

S709, the terminal 100 receives one or more SLC PDU2.

The terminal 100 may receive one or more SLC PDU2.

In one possible implementation, after the terminal 100 has registered one or more SLC PDU1, the north bucket network device 200 replies that the one or more SLC PDU2 has been registered.

When the letter download completion indication field in the letter download query result message indicates that there is a letter in the follow-up, the terminal 100 may receive one or more SLC PDU2 in the letter download query result message, and after the terminal 100 collects one SLC SDU, the terminal 100 may reply to the north bucket network device 200 with an ACK acknowledgement. After receiving the ACK information corresponding to all SLC SDUs, the beidou network device 200 may send a letter sending indication message to the application layer. After receiving the letter sending indication message, the application layer of the beidou network equipment 200 continues to send the content of the letter. The Beidou network device 200 can package the content of the letter into another letter downloading query result message.

Alternatively, when the letter download completion indication field in the letter download query result message indicates that there is a letter in the follow-up, the terminal 100 may receive a download indication from the user after completing one letter, and the terminal 100 downloads the follow-up letter based on the download indication.

Illustratively, the data format of the letter transmission indication message may be as shown in table 12 below.

Table 12

As shown in table 12, the receiver number field and the ACK indication field may be included in the letter transmission indication message. Wherein the receiving party number field is used for indicating the mobile phone number of the receiving equipment of the letter. In the embodiment of the present application, the receiving number field may be a mobile phone number of the terminal 100. The ACK indication field is used to indicate whether the beidou network device 200 successfully transmits the last letter download query result message. The ACK indication field may be 1bit in length. For example, when the ACK indication field is 0, the ACK indication field may be used to indicate that the beidou network device 200 has not successfully sent the last letter download query result message. When the ACK indication field is 1, the ACK indication field may be used to indicate that the beidou network device 200 successfully sends the last letter download query result packet.

Further, the terminal 100 may parse out the user ID field in the frame header of each SLC PDU2 at the SLC layer. If the terminal 100 parses the identity (e.g., the mobile phone number 138 xxxxxxx) of the terminal 100 from the user ID field to be the same, the terminal 100 uploads the one or more SLC PDU2 to the MDCP layer for further parsing; if the terminal 100 does not parse the identity of the terminal 100 from the user ID field, the terminal 100 may determine that the SLC PDU2 is not transmitted to the terminal 100, and the terminal 100 may discard the SLC PDU2.

S710, the terminal 100 spells one or more SLC PDU2 into a letter download inquiry result message.

Specifically, the terminal 100 may splice one or more SLC PDU2 into one or more SLC SDUs at the SLC layer. The terminal 100 then uploads one or more SLC SDUs to the MDCP layer as one or more MDCP PDUs of the MDCP layer. The terminal 100 may then splice one or more MDCP PDUs into a MDCP SDU at the MDCP layer. The terminal 100 may then upload the MDCP SDU to the APP layer as a letter download query result message. Reference may be made to the description of the process of decapsulating the outbound data of the beidou communication system in fig. 6, which is not repeated here.

S711, the terminal 100 analyzes the content of the letter sent to the terminal 100 by the target terminal in the letter downloading inquiry result message.

The terminal 100 may parse the letter content field in the letter download query result message at the APP layer, and obtain the content of the letter sent by the target terminal to the terminal 100 from the letter content field.

S712, the terminal 100 displays the content of the letter sent by the target terminal to the terminal 100.

The terminal 100 may display the contents of the letter the target terminal sends to the terminal 100 in a display screen. Or the terminal 100 voice broadcasts the content of the letter sent by the target terminal to the terminal 100, which is not limited in the embodiment of the present application. It can be understood that, after the beidou network device 200 sends a letter download query result message, the following letters are sent to the terminal 100, and the letter content of the next letter can be continuously sent to the terminal according to the steps S706-S712.

Alternatively, the user of the terminal 100 may first inquire about the mailbox profile before downloading the letter. I.e. inquire about the number of letters sent by other terminals to the terminal 100. After the beidou network device 200 sends the number of letters sent to the terminal 100 by other terminals to the terminal 100, the terminal 100 can select the letters to be downloaded for downloading the letters.

In this way, by the mail downloading query method in the Beidou communication system provided by the embodiment of the application, the terminal 100 does not reside in the cellular network under the Beidou network, and can query the content of the mail sent to the terminal 100 by other terminals.

In the embodiment of the present application, the sender ID field in the mail download inquiry request message may be referred to as a first sender ID field. The sender ID field in the letter download inquiry result message may be referred to as a second sender ID field.

For example, the contents of the letters transmitted from the terminal 100 to the terminal 100 by the terminal 100 displaying the target terminals in the white list, the target terminals in the non-white list, and all the target terminals in the display screen may be as shown in fig. 8A to 8C.

As shown in fig. 8A, when a user downloads content of a letter addressed to the terminal 100 by a single target terminal (target terminal in a white list or target terminal in a non-white list) at the terminal 100, for example, a dad terminal, the terminal 100 may display the user interface 80A. The user interface 80A may include: status bar 803, message notification box 804, wherein:

the status bar 803 may include a signal strength indicator 801 of a mobile communication signal (which may be also referred to as a cellular signal) and a beidou communication icon 802, where the signal strength indicator 801 of the mobile communication signal (which may be also referred to as a cellular signal) is used to indicate that the current terminal 100 has no mobile communication signal, and the beidou communication icon 802 is used to indicate that the terminal 100 has turned on the beidou communication function.

The message notification box 804 is used to display the content of the letter sent by the target terminal to the terminal 100. The message notification box 804 may display the time of receipt of the letter, the sender of the letter, and the content of the letter, the original time of transmission of the letter. For example, the time for receipt of the letter is "3 minutes ago", the sender of the letter "dad", the content of the letter "when you return home", the original time for transmission of the letter is "36 hours ago", etc.

It will be appreciated that the content of the letters sent to the terminal 100 by a single target terminal (target terminal in the white list or target terminal in the non-white list) may be downloaded by the user at the terminal 100, and the letters sent to the terminal 100 by the single target terminal may be one letter or multiple letters, which is not limited by the embodiment of the present application. If there are multiple letters of a letter sent by a single target terminal 100 to the terminal 100, the terminal 100 may download the contents of the multiple letters sent by the single target terminal to the terminal 100.

In one possible implementation, when the user downloads all letters sent by all target terminals to the terminal 100 at the terminal 100, the terminal 100 may download all letters at once and display the contents of all letters.

Illustratively, as shown in fig. 8B, when a user downloads at the terminal 100 all letters (for example, all letters are 3 letters) that the target terminal sends to the terminal 100, the terminal 100 may display the user interface 80B. The user interface 80B may include: status bar 803, message notification box 804, message notification box 805, message notification box 806, message notification box 807, wherein:

The status bar 803 and the message notification bar 804 may refer to the description in fig. 8A, and are not described herein.

The message notification box 805 is for displaying the content of the letter sent by the target terminal to the terminal 100. The message notification box 805 may display the time of receipt of the letter, the sender of the letter, and the content of the letter, the original time of transmission of the letter. For example, the letter receiving time is "3 minutes ago", the letter sender "mom", the letter content "safety is noted outside", the original sending time of the letter is "38 hours ago", and so on.

The message notification box 807 is for displaying the content of the letter sent by the target terminal to the terminal 100. The message notification box 807 may have displayed therein the time of receipt of the letter, the sender of the letter, and the content of the letter, the original time of transmission of the letter. For example, the time of sending the letter is "3 minutes ago", the sender of the letter is "small", the content of the letter is "where you are", the original time of sending the letter is "40 hours ago", etc.

The message notification box 806 is used to prompt that the letter has been downloaded. The message notification box 806 may display a prompt, such as "mail download complete".

Alternatively, in one possible implementation, when the user downloads, at the terminal 100, all letters sent by the target terminal to the terminal 100, the terminal 100 may download a letter first, and then prompt the user whether to download a subsequent letter. If the user selects to download, the terminal 100 downloads the next letter; if the user chooses not to download, the terminal 100 stops downloading the correspondence.

Illustratively, as shown in FIG. 8C, when the user downloads at the terminal 100 all letters sent by the target terminal to the terminal 100, the terminal 100 may display the user interface 80B. The user interface 80B may include: status bar 803, message notification box 804, message prompt box 808, wherein:

Message prompt box 808 is used to prompt the user whether to download a subsequent letter. As shown in fig. 8C, controls 8081 and 8082 may be included in the message prompt 808. If the user clicks the control 8081, the terminal 100 may continue to download the next letter based on the user operation. If the user clicks the control 8082, the terminal 100 may stop downloading letters based on the user operation.

Further, in one possible implementation, when the user downloads, at the terminal 100, all the letters sent to the terminal 100 by the target terminal, the beidou network device 200 queries, in the short message center 41, that the number of letters sent to the terminal 100 is greater than a first threshold (for example, 16), and the beidou network device 200 sends only the letters of the first threshold number to the terminal 100. When the terminal 100 reloads all the letters sent to the terminal 100 by the target terminal next time, the Beidou network equipment 200 sends the letters after the first threshold value to the terminal 100.

An exemplary terminal 100 provided by an embodiment of the present application is described below.

Fig. 8D is a schematic structural diagram of a terminal 100 according to an embodiment of the present application.

The embodiment will be specifically described below with reference to the terminal 100 as an example. It should be understood that terminal 100 may have more or fewer components than shown, may combine two or more components, or may have a different configuration of components. The various components shown in the figures may be implemented in hardware, software, or a combination of hardware and software, including one or more signal processing and/or application specific integrated circuits.

The terminal 100 may include: processor 110, external memory interface 120, internal memory 121, universal serial bus (universal serial bus, USB) interface 130, charge management module 140, power management module 141, battery 142, antenna 1, antenna 2, mobile communication module 150, wireless communication module 160, audio module 170, speaker 170A, receiver 170B, microphone 170C, headset interface 170D, sensor module 180, keys 190, motor 191, indicator 192, camera 193, display 194, and subscriber identity module (subscriber identification module, SIM) card interface 195, etc. The sensor module 180 may include a pressure sensor 180A, a gyro sensor 180B, an air pressure sensor 180C, a magnetic sensor 180D, an acceleration sensor 180E, a distance sensor 180F, a proximity sensor 180G, a fingerprint sensor 180H, a temperature sensor 180J, a touch sensor 180K, an ambient light sensor 180L, a bone conduction sensor 180M, and the like.

It should be understood that the structure illustrated in the embodiments of the present application does not constitute a specific limitation on the terminal 100. In other embodiments of the application, terminal 100 may include more or less components than shown, or certain components may be combined, or certain components may be split, or different arrangements of components. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

The processor 110 may include one or more processing units, such as: the processor 110 may include an application processor (application processor, AP), a modem processor, a graphics processor (graphics processing unit, GPU), an image signal processor (IMAGE SIGNAL processor, ISP), a controller, a memory, a video codec, a digital signal processor (DIGITAL SIGNAL processor, DSP), a baseband processor, and/or a neural Network Processor (NPU), etc. Wherein the different processing units may be separate devices or may be integrated in one or more processors.

The controller may be a neural hub and a command center of the terminal 100, among others. The controller can generate operation control signals according to the instruction operation codes and the time sequence signals to finish the control of instruction fetching and instruction execution.

A memory may also be provided in the processor 110 for storing instructions and data. In some embodiments, the memory in the processor 110 is a cache memory. The memory may hold instructions or data that the processor 110 has just used or recycled. If the processor 110 needs to reuse the instruction or data, it can be called directly from the memory. Repeated accesses are avoided and the latency of the processor 110 is reduced, thereby improving the efficiency of the system.

In some embodiments, the processor 110 may include one or more interfaces. The interfaces may include an integrated circuit (inter-INTEGRATED CIRCUIT, I2C) interface, an integrated circuit built-in audio (inter-INTEGRATED CIRCUIT SOUND, I2S) interface, a pulse code modulation (pulse code modulation, PCM) interface, a universal asynchronous receiver transmitter (universal asynchronous receiver/transmitter, UART) interface, a mobile industry processor interface (mobile industry processor interface, MIPI), a general-purpose input/output (GPIO) interface, a subscriber identity module (subscriber identity module, SIM) interface, and/or a universal serial bus (universal serial bus, USB) interface, among others.

The I2C interface is a bi-directional synchronous serial bus comprising a serial data line (SERIAL DATA LINE, SDA) and a serial clock line (derail clock line, SCL). In some embodiments, the processor 110 may contain multiple sets of I2C buses. The processor 110 may be coupled to the touch sensor 180K, charger, flash, camera 193, etc., respectively, through different I2C bus interfaces. For example: the processor 110 may be coupled to the touch sensor 180K through an I2C interface, so that the processor 110 and the touch sensor 180K communicate through an I2C bus interface to implement a touch function of the terminal 100.

The I2S interface may be used for audio communication. In some embodiments, the processor 110 may contain multiple sets of I2S buses. The processor 110 may be coupled to the audio module 170 via an I2S bus to enable communication between the processor 110 and the audio module 170. In some embodiments, the audio module 170 may transmit an audio signal to the wireless communication module 160 through the I2S interface, to implement a function of answering a call through the bluetooth headset.

PCM interfaces may also be used for audio communication to sample, quantize and encode analog signals. In some embodiments, the audio module 170 and the wireless communication module 160 may be coupled through a PCM bus interface. In some embodiments, the audio module 170 may also transmit audio signals to the wireless communication module 160 through the PCM interface to implement a function of answering a call through the bluetooth headset. Both the I2S interface and the PCM interface may be used for audio communication.

The UART interface is a universal serial data bus for asynchronous communications. The bus may be a bi-directional communication bus. It converts the data to be transmitted between serial communication and parallel communication. In some embodiments, a UART interface is typically used to connect the processor 110 with the wireless communication module 160. For example: the processor 110 communicates with a bluetooth module in the wireless communication module 160 through a UART interface to implement a bluetooth function. In some embodiments, the audio module 170 may transmit an audio signal to the wireless communication module 160 through a UART interface, to implement a function of playing music through a bluetooth headset.

The MIPI interface may be used to connect the processor 110 to peripheral devices such as a display 194, a camera 193, and the like. The MIPI interfaces include camera serial interfaces (CAMERA SERIAL INTERFACE, CSI), display serial interfaces (DISPLAY SERIAL INTERFACE, DSI), and the like. In some embodiments, processor 110 and camera 193 communicate through a CSI interface to implement the photographing function of terminal 100. The processor 110 and the display 194 communicate through a DSI interface to implement the display function of the terminal 100.

The GPIO interface may be configured by software. The GPIO interface may be configured as a control signal or as a data signal. In some embodiments, a GPIO interface may be used to connect the processor 110 with the camera 193, the display 194, the wireless communication module 160, the audio module 170, the sensor module 180, and the like. The GPIO interface may also be configured as an I2C interface, an I2S interface, a UART interface, an MIPI interface, etc.

The SIM interface may be used to communicate with the SIM card interface 195 to perform functions of transferring data to or reading data from the SIM card.

The USB interface 130 is an interface conforming to the USB standard specification, and may specifically be a Mini USB interface, a Micro USB interface, a USB Type C interface, or the like. The USB interface 130 may be used to connect a charger to charge the terminal 100, or may be used to transfer data between the terminal 100 and a peripheral device. And can also be used for connecting with a headset, and playing audio through the headset. The interface may also be used to connect other terminals, such as AR devices, etc.

It should be understood that the interfacing relationship between the modules illustrated in the embodiment of the present application is only illustrative, and does not limit the structure of the terminal 100. In other embodiments of the present application, the terminal 100 may also use different interfacing manners in the above embodiments, or a combination of multiple interfacing manners.

The charge management module 140 is configured to receive a charge input from a charger. The charger can be a wireless charger or a wired charger.

The power management module 141 is used for connecting the battery 142, and the charge management module 140 and the processor 110. The power management module 141 receives input from the battery 142 and/or the charge management module 140 and provides power to the processor 110, the internal memory 121, the external memory, the display 194, the camera 193, the wireless communication module 160, and the like.

The wireless communication function of the terminal 100 may be implemented by the antenna 1, the antenna 2, the mobile communication module 150, the wireless communication module 160, a modem processor, a baseband processor, and the like.

The antennas 1 and 2 are used for transmitting and receiving electromagnetic wave signals. Each antenna in terminal 100 may be configured to cover a single or multiple communication bands. Different antennas may also be multiplexed to improve the utilization of the antennas. For example: the antenna 1 may be multiplexed into a diversity antenna of a wireless local area network. In other embodiments, the antenna may be used in conjunction with a tuning switch.

The mobile communication module 150 may provide a solution including 2G/3G/4G/5G wireless communication applied to the terminal 100. The mobile communication module 150 may include at least one filter, switch, power amplifier, low noise amplifier (low noise amplifier, LNA), etc. The mobile communication module 150 may receive electromagnetic waves from the antenna 1, perform processes such as filtering, amplifying, and the like on the received electromagnetic waves, and transmit the processed electromagnetic waves to the modem processor for demodulation. The mobile communication module 150 can amplify the signal modulated by the modem processor, and convert the signal into electromagnetic waves through the antenna 1 to radiate. In some embodiments, at least some of the functional modules of the mobile communication module 150 may be disposed in the processor 110. In some embodiments, at least some of the functional modules of the mobile communication module 150 may be provided in the same device as at least some of the modules of the processor 110.

The modem processor may include a modulator and a demodulator. The modulator is used for modulating the low-frequency baseband signal to be transmitted into a medium-high frequency signal. The demodulator is used for demodulating the received electromagnetic wave signal into a low-frequency baseband signal. The demodulator then transmits the demodulated low frequency baseband signal to the baseband processor for processing. The low frequency baseband signal is processed by the baseband processor and then transferred to the application processor. The application processor outputs sound signals through an audio device (not limited to the speaker 170A, the receiver 170B, etc.), or displays images or video through the display screen 194. In some embodiments, the modem processor may be a stand-alone device. In other embodiments, the modem processor may be provided in the same device as the mobile communication module 150 or other functional module, independent of the processor 110.

The wireless communication module 160 may provide solutions for wireless communication including wireless local area network (wireless local area networks, WLAN) (e.g., wireless fidelity (WIRELESS FIDELITY, wi-Fi) network), bluetooth (BT), global navigation satellite system (global navigation SATELLITE SYSTEM, GNSS), beidou communication module, frequency modulation (frequency modulation, FM), near field communication technology (NEAR FIELD communication, NFC), infrared technology (IR), etc., applied to the terminal 100. The wireless communication module 160 may be one or more devices that integrate at least one communication processing module. The wireless communication module 160 receives electromagnetic waves via the antenna 2, modulates the electromagnetic wave signals, filters the electromagnetic wave signals, and transmits the processed signals to the processor 110. The wireless communication module 160 may also receive a signal to be transmitted from the processor 110, frequency modulate it, amplify it, and convert it to electromagnetic waves for radiation via the antenna 2.

The Beidou communication module can be used for communicating with the Beidou network equipment 200. The Beidou communication module can support short message transmission with the Beidou network equipment 200.

In some embodiments, antenna 1 and mobile communication module 150 of terminal 100 are coupled, and antenna 2 and wireless communication module 160 are coupled, such that terminal 100 may communicate with a network and other devices via wireless communication techniques. The wireless communication techniques can include the Global System for Mobile communications (global system for mobile communications, GSM), general packet radio service (GENERAL PACKET radio service, GPRS), code division multiple access (code division multiple access, CDMA), wideband code division multiple access (wideband code division multiple access, WCDMA), time division code division multiple access (time-division code division multiple access, TD-SCDMA), long term evolution (long term evolution, LTE), BT, GNSS, WLAN, NFC, FM, and/or IR techniques, among others. The GNSS may include a global satellite positioning system (global positioning system, GPS), a global navigation satellite system (global navigation SATELLITE SYSTEM, GLONASS), a beidou satellite navigation system (beidou navigation SATELLITE SYSTEM, BDS), a quasi zenith satellite system (quasi-zenith SATELLITE SYSTEM, QZSS) and/or a satellite based augmentation system (SATELLITE BASED AUGMENTATION SYSTEMS, SBAS).

Terminal 100 implements display functions via a GPU, display 194, and application processor, etc. The GPU is a microprocessor for image processing, and is connected to the display 194 and the application processor. The GPU is used to perform mathematical and geometric calculations for graphics rendering. Processor 110 may include one or more GPUs that execute program instructions to generate or change display information.

The display screen 194 is used to display images, videos, and the like. The display 194 includes a display panel. The display panel may employ a Liquid Crystal Display (LCD) CRYSTAL DISPLAY, an organic light-emitting diode (OLED), an active-matrix organic LIGHT EMITTING diode (AMOLED), a flexible light-emitting diode (FLED), miniled, microLed, micro-oLed, a quantum dot LIGHT EMITTING diode (QLED), or the like. In some embodiments, the terminal 100 may include 1 or N display screens 194, N being a positive integer greater than 1.

The terminal 100 may implement photographing functions through an ISP, a camera 193, a video codec, a GPU, a display 194, an application processor, and the like.

The ISP is used to process data fed back by the camera 193. For example, when photographing, the shutter is opened, light is transmitted to the camera photosensitive element through the lens, the optical signal is converted into an electric signal, and the camera photosensitive element transmits the electric signal to the ISP for processing and is converted into an image visible to naked eyes. ISP can also optimize the noise, brightness and skin color of the image. The ISP can also optimize parameters such as exposure, color temperature and the like of a shooting scene. In some embodiments, the ISP may be provided in the camera 193.

The camera 193 is used to capture still images or video. The object generates an optical image through the lens and projects the optical image onto the photosensitive element. The photosensitive element may be a charge coupled device (charge coupled device, CCD) or a Complementary Metal Oxide Semiconductor (CMOS) phototransistor. The photosensitive element converts the optical signal into an electrical signal, which is then transferred to the ISP to be converted into a digital image signal. The ISP outputs the digital image signal to the DSP for processing. The DSP converts the digital image signal into an image signal in a standard RGB, YUV, or the like format. In some embodiments, terminal 100 may include 1 or N cameras 193, N being a positive integer greater than 1.

The digital signal processor is used for processing digital signals, and can process other digital signals besides digital image signals. For example, when the terminal 100 selects a frequency bin, the digital signal processor is used to fourier transform the frequency bin energy, etc.

Video codecs are used to compress or decompress digital video. The terminal 100 may support one or more video codecs. In this way, the terminal 100 may play or record video in a variety of encoding formats, such as: dynamic picture experts group (moving picture experts group, MPEG) 1, MPEG2, MPEG3, MPEG4, etc.

The NPU is a neural-network (NN) computing processor, and can rapidly process input information by referencing a biological neural network structure, for example, referencing a transmission mode between human brain neurons, and can also continuously perform self-learning. Applications such as intelligent cognition of the terminal 100 can be implemented by the NPU, for example: image recognition, face recognition, speech recognition, text understanding, etc.

The internal memory 121 may include one or more random access memories (random access memory, RAM) and one or more non-volatile memories (NVM).

The random access memory may include a static random-access memory (SRAM), a dynamic random-access memory (dynamic random access memory, DRAM), a synchronous dynamic random-access memory (synchronous dynamic random access memory, SDRAM), a double data rate synchronous dynamic random-access memory (doubledata rate synchronous dynamic random access memory, DDR SDRAM, such as fifth generation DDR SDRAM is commonly referred to as DDR5 SDRAM), etc.;

The nonvolatile memory may include a disk storage device, a flash memory (flash memory).

The FLASH memory may include NOR FLASH, NAND FLASH, 3D NAND FLASH, etc. divided according to an operation principle, may include single-level memory cells (SLC-LEVEL CELL), multi-level memory cells (multi-LEVEL CELL, MLC), triple-level memory cells (LEVEL CELL, TLC), quad-LEVEL CELL, QLC), etc. divided according to a memory cell potential order, may include general FLASH memory (english: universal FLASH storage, UFS), embedded multimedia memory card (eMMC) MEDIA CARD, eMMC), etc. divided according to a memory specification.

The random access memory may be read directly from and written to by the processor 110, may be used to store executable programs (e.g., machine instructions) for an operating system or other on-the-fly programs, may also be used to store data for users and applications, and the like.

The nonvolatile memory may store executable programs, store data of users and applications, and the like, and may be loaded into the random access memory in advance for the processor 110 to directly read and write.

The terminal 100 may implement audio functions through an audio module 170, a speaker 170A, a receiver 170B, a microphone 170C, an earphone interface 170D, an application processor, and the like. Such as music playing, recording, etc.

The audio module 170 is used to convert digital audio information into an analog audio signal output and also to convert an analog audio input into a digital audio signal. The audio module 170 may also be used to encode and decode audio signals. In some embodiments, the audio module 170 may be disposed in the processor 110, or a portion of the functional modules of the audio module 170 may be disposed in the processor 110.

The speaker 170A, also referred to as a "horn," is used to convert audio electrical signals into sound signals. The terminal 100 can listen to music or to handsfree calls through the speaker 170A.

A receiver 170B, also referred to as a "earpiece", is used to convert the audio electrical signal into a sound signal. When the terminal 100 receives a telephone call or voice message, it is possible to receive voice by approaching the receiver 170B to the human ear.

Microphone 170C, also referred to as a "microphone" or "microphone", is used to convert sound signals into electrical signals. When making a call or transmitting voice information, the user can sound near the microphone 170C through the mouth, inputting a sound signal to the microphone 170C. The terminal 100 may be provided with at least one microphone 170C. In other embodiments, the terminal 100 may be provided with two microphones 170C, and may implement a noise reduction function in addition to collecting sound signals. In other embodiments, the terminal 100 may be further provided with three, four or more microphones 170C to collect sound signals, reduce noise, identify the source of sound, implement directional recording functions, etc.

The earphone interface 170D is used to connect a wired earphone. The earphone interface 170D may be a USB interface 130 or a 3.5mm open mobile terminal platform (open mobile terminal platform, OMTP) standard interface, a american cellular telecommunications industry association (cellular telecommunications industry association of the USA, CTIA) standard interface.

The pressure sensor 180A is used to sense a pressure signal, and may convert the pressure signal into an electrical signal. In some embodiments, the pressure sensor 180A may be disposed on the display screen 194. The pressure sensor 180A is of various types, such as a resistive pressure sensor, an inductive pressure sensor, a capacitive pressure sensor, and the like. The capacitive pressure sensor may be a capacitive pressure sensor comprising at least two parallel plates with conductive material. The capacitance between the electrodes changes when a force is applied to the pressure sensor 180A. The terminal 100 determines the strength of the pressure according to the change of the capacitance. When a touch operation is applied to the display 194, the terminal 100 detects the intensity of the touch operation according to the pressure sensor 180A. The terminal 100 may also calculate the location of the touch based on the detection signal of the pressure sensor 180A. In some embodiments, touch operations that act on the same touch location, but at different touch operation strengths, may correspond to different operation instructions. For example: and executing an instruction for checking the short message when the touch operation with the touch operation intensity smaller than the first pressure threshold acts on the short message application icon. And executing an instruction for newly creating the short message when the touch operation with the touch operation intensity being greater than or equal to the first pressure threshold acts on the short message application icon.

The gyro sensor 180B may be used to determine a motion gesture of the terminal 100. In some embodiments, the angular velocity of terminal 100 about three axes (i.e., x, y, and z axes) may be determined by gyro sensor 180B. The gyro sensor 180B may be used for photographing anti-shake. Illustratively, when the shutter is pressed, the gyro sensor 180B detects the angle of the shake of the terminal 100, calculates the distance to be compensated by the lens module according to the angle, and allows the lens to counteract the shake of the terminal 100 by the reverse motion, thereby realizing anti-shake. The gyro sensor 180B may also be used for navigating, somatosensory game scenes.

The air pressure sensor 180C is used to measure air pressure. In some embodiments, the terminal 100 calculates altitude from barometric pressure values measured by the barometric pressure sensor 180C, aiding in positioning and navigation.

The magnetic sensor 180D includes a hall sensor. The terminal 100 may detect the opening and closing of the flip cover using the magnetic sensor 180D. In some embodiments, when the terminal 100 is a folder, the terminal 100 may detect opening and closing of the folder according to the magnetic sensor 180D. And then according to the detected opening and closing state of the leather sheath or the opening and closing state of the flip, the characteristics of automatic unlocking of the flip and the like are set.

The acceleration sensor 180E may detect the magnitude of acceleration of the terminal 100 in various directions (typically three axes). The magnitude and direction of gravity may be detected when the terminal 100 is stationary. The method can also be used for identifying the gesture of the terminal, and is applied to the applications such as horizontal and vertical screen switching, pedometers and the like.

A distance sensor 180F for measuring a distance. The terminal 100 may measure the distance by infrared or laser. In some embodiments, the terminal 100 may range using the distance sensor 180F to achieve quick focusing.

The proximity light sensor 180G may include, for example, a Light Emitting Diode (LED) and a light detector, such as a photodiode. The light emitting diode may be an infrared light emitting diode. The terminal 100 emits infrared light outward through the light emitting diode. The terminal 100 detects infrared reflected light from nearby objects using a photodiode. When sufficient reflected light is detected, it may be determined that there is an object near the terminal 100. When insufficient reflected light is detected, the terminal 100 may determine that there is no object in the vicinity of the terminal 100. The terminal 100 can detect that the user holds the terminal 100 close to the ear by using the proximity light sensor 180G, so as to automatically extinguish the screen for the purpose of saving power. The proximity light sensor 180G may also be used in holster mode, pocket mode to automatically unlock and lock the screen.

The ambient light sensor 180L is used to sense ambient light level. The terminal 100 may adaptively adjust the brightness of the display 194 according to the perceived ambient light level. The ambient light sensor 180L may also be used to automatically adjust white balance when taking a photograph. The ambient light sensor 180L may also cooperate with the proximity light sensor 180G to detect whether the terminal 100 is in a pocket to prevent false touches.

The fingerprint sensor 180H is used to collect a fingerprint. The terminal 100 can utilize the collected fingerprint characteristics to realize fingerprint unlocking, access an application lock, fingerprint photographing, fingerprint incoming call answering and the like.

The temperature sensor 180J is for detecting temperature. In some embodiments, terminal 100 performs a temperature processing strategy using the temperature detected by temperature sensor 180J. For example, when the temperature reported by the temperature sensor 180J exceeds a threshold, the terminal 100 performs a reduction in performance of a processor located near the temperature sensor 180J in order to reduce power consumption for implementing thermal protection. In other embodiments, when the temperature is below another threshold, the terminal 100 heats the battery 142 to avoid the terminal 100 from being abnormally shut down due to low temperatures. In other embodiments, when the temperature is below a further threshold, terminal 100 performs boosting of the output voltage of battery 142 to avoid abnormal shutdown caused by low temperatures.

The touch sensor 180K, also referred to as a "touch panel". The touch sensor 180K may be disposed on the display screen 194, and the touch sensor 180K and the display screen 194 form a touch screen, which is also called a "touch screen". The touch sensor 180K is for detecting a touch operation acting thereon or thereabout. The touch sensor may communicate the detected touch operation to the application processor to determine the touch event type. Visual output related to touch operations may be provided through the display 194. In other embodiments, the touch sensor 180K may be disposed on the surface of the terminal 100 at a different location than the display 194.

The keys 190 include a power-on key, a volume key, etc. The keys 190 may be mechanical keys. Or may be a touch key. The terminal 100 may receive key inputs, generating key signal inputs related to user settings and function controls of the terminal 100.

The motor 191 may generate a vibration cue. The motor 191 may be used for incoming call vibration alerting as well as for touch vibration feedback. For example, touch operations acting on different applications (e.g., photographing, audio playing, etc.) may correspond to different vibration feedback effects. The motor 191 may also correspond to different vibration feedback effects by touching different areas of the display screen 194. Different application scenarios (such as time reminding, receiving information, alarm clock, game, etc.) can also correspond to different vibration feedback effects. The touch vibration feedback effect may also support customization.

The indicator 192 may be an indicator light, may be used to indicate a state of charge, a change in charge, a message indicating a missed call, a notification, etc.

The SIM card interface 195 is used to connect a SIM card. The SIM card may be contacted and separated from the terminal 100 by being inserted into the SIM card interface 195 or by being withdrawn from the SIM card interface 195. The terminal 100 may support 1 or N SIM card interfaces, N being a positive integer greater than 1. The SIM card interface 195 may support Nano SIM cards, micro SIM cards, and the like. The same SIM card interface 195 may be used to insert multiple cards simultaneously. The types of the plurality of cards may be the same or different. The SIM card interface 195 may also be compatible with different types of SIM cards. The SIM card interface 195 may also be compatible with external memory cards. The terminal 100 interacts with the network through the SIM card to realize functions such as call and data communication.

The foregoing details of the method provided by the present application, and in order to facilitate better implementing the foregoing aspects of the embodiments of the present application, the embodiments of the present application further provide corresponding apparatuses or devices.

The embodiment of the present application may divide the functional modules of the terminal 100 and the beidou network device 200 according to the above method example, for example, each functional module may be divided corresponding to each function, or two or more functions may be integrated into one processing module. The integrated modules may be implemented in hardware or in software functional modules. It should be noted that, in the embodiment of the present application, the division of the modules is schematic, which is merely a logic function division, and other division manners may be implemented in actual implementation.

The communication device according to the embodiment of the present application will be described in detail with reference to fig. 9 to 12.

In the case of using an integrated unit, referring to fig. 9, fig. 9 is a schematic structural diagram of a communication device 900 according to an embodiment of the present application. The communication device 900 may be the terminal 100 in the above embodiment. Alternatively, the communication device 900 may be a chip/chip system, such as a Beidou communication chip. As shown in fig. 9, the communication apparatus 900 may include a transceiving unit 910 and a processing unit 920.

In one design, the transceiver unit 910 may be configured to send a mail download query request message to the north bucket network device 200;

optionally, the transceiver unit 910 may be further configured to receive a letter download query result packet.

The processing unit 920 may be configured to issue the letter download query request packet to the MDCP layer, where the letter download query request packet may be segmented into one or more MDCP PDUs.

Optionally, the processing unit 920 may be further configured to issue one or more MDCP PDUs to the SLC layer, where each MDCP PDU may be segmented into one or more SLC PDU1.

Optionally, the transceiver unit 910 may be further configured to perform the functional steps related to transmission and reception performed by the terminal 100 in the method embodiment shown in fig. 7.

Optionally, the processing unit 920 may be further configured to perform the functional steps related to protocol parsing and encapsulation and operation determination performed by the terminal 100 in the method embodiment shown in fig. 7.

It should be understood that the communication device 900 in this design may correspond to the method steps performed by the terminal 100 in the foregoing embodiment, and are not described herein for brevity.

In the case of using an integrated unit, referring to fig. 10, fig. 10 is a schematic structural diagram of a communication device 1000 according to an embodiment of the present application. The communication device 1000 may be the beidou network device 200 in the above embodiment. Alternatively, the communication apparatus 1000 may be a specific network element in the beidou network device 200, for example, a beidou ground receiving station 31, a beidou ground transmitting station 35, a signal receiving processing device 32, a signal processing center 33, a signal sending processing device 36, an operation control center 37, and a beidou short message fusion communication platform 34, or a combination of a plurality of network elements. As shown in fig. 10, the communication device 1000 may include a transceiver unit 1010 and a processing unit 1020.

In one design, the transceiver 1010 may be configured to receive a mail download query request message.

The transceiver 1010 may be further configured to send a letter download query result message.

The processing unit 1020 may be configured to splice one or more SLC PDU1 into a letter download query request message.

The processing unit 1020 may be further configured to splice one or more SLC PDU1 into one or more SLC SDUs at the SLC layer, and upload the one or more SLC SDUs to the MDCP layer as one or more MDCP PDU of the MDCP layer; splicing one or more MDCP PDUs into MDCP SDUs at an MDCP layer; and then, the MDCP SDU can be used for uploading the MDCP SDU to an APP layer as a mail downloading inquiry request message.

Optionally, the transceiver 1010 may be further configured to perform the function steps related to sending and receiving performed by the beidou network device 200 in the method embodiment shown in fig. 7.

Optionally, the processing unit 1020 may be further configured to execute the functional steps related to protocol parsing and packaging and operation determination performed by the beidou network device 200 in the method embodiment shown in fig. 7.

It should be understood that the communication device 1000 in this design may correspond to the method steps executed by the beidou network device 200 in the foregoing embodiment, and are not described herein for brevity.

While the terminal 100 and the beidou network device 200 according to the embodiments of the present application have been described above, it should be understood that any product having any form of the functions of the terminal 100 described in fig. 9, and any product having any form of the functions of the beidou network device 200 described in fig. 10 fall within the protection scope of the embodiments of the present application.

As one possible product form, the terminal 100 according to the embodiments of the present application may be implemented by a general bus architecture.

Referring to fig. 11, fig. 11 is a schematic structural diagram of a communication device 1100 according to an embodiment of the present application. The communication device 1100 may be the terminal 100, or a device therein. As shown in fig. 11, the communication device 1100 includes a processor 1101 and a transceiver 1102 in communication with the processor's internal connections. The processor 1101 is a general-purpose processor, a special-purpose processor, or the like. For example, a baseband processor or a central processing unit for satellite communications. The baseband processor of satellite communications may be used to process satellite communications protocols and satellite communications data, and the central processor may be used to control communications devices (e.g., baseband chips, terminals, terminal chips, etc.), execute computer programs, and process data for the computer programs. The transceiver 1102 may be referred to as a transceiver unit, a transceiver circuit, or the like, for implementing a transceiver function. The transceiver 1102 may include a receiver, which may be referred to as a receiver or a receiving circuit, etc., for implementing a receiving function; the transmitter may be referred to as a transmitter or a transmitting circuit, etc., for implementing a transmitting function. Optionally, the communication device 1100 may further comprise an antenna 1103 and/or a radio frequency unit (not shown). The antenna 1103 and/or the radio frequency unit may be located inside the communication device 1100 or may be separate from the communication device 1100, i.e. the antenna 1103 and/or the radio frequency unit may be remotely or distributively deployed.

Optionally, the communication device 1100 may include one or more memories 1104, on which instructions may be stored, which may be a computer program that may be executed on the communication device 1100, such that the communication device 1100 performs the methods described in the method embodiments above. Optionally, the memory 1104 may also have data stored therein. The communication device 1100 and the memory 1104 may be provided separately or may be integrated.

The processor 1101, transceiver 1102, and memory 1104 may be connected by a communication bus.

In one design, the communication device 1100 may be used to perform the functions of the terminal 100 in the foregoing embodiments: the processor 1101 may be configured to perform the functional steps described above with respect to protocol parsing and encapsulation and operational determination performed by the terminal 100 in the embodiments illustrated in fig. 3 and 5 and fig. 7 and/or other processes for the techniques described herein; the transceiver 1102 may be used to perform the functional steps described above with respect to protocol parsing and encapsulation and operational determination performed by the terminal 100 in the embodiments illustrated in fig. 3 and 5 and fig. 7 and/or other processes for the techniques described herein.

In either of the designs described above, a transceiver for implementing the receive and transmit functions may be included in the processor 1101. For example, the transceiver may be a transceiver circuit, or an interface circuit. The transceiver circuitry, interface or interface circuitry for implementing the receive and transmit functions may be separate or may be integrated. The transceiver circuit, interface or interface circuit may be used for reading and writing codes/data, or the transceiver circuit, interface or interface circuit may be used for transmitting or transferring signals.

In any of the above designs, the processor 1101 may store instructions, which may be a computer program, running on the processor 1101 may cause the communication device 1100 to perform the method steps performed by the terminal 100 in the above-described method embodiments. The computer program may be solidified in the processor 1101, in which case the processor 1101 may be implemented by hardware.

In one implementation, the communications apparatus 1100 can include circuitry that can implement the functions of transmitting or receiving or communicating in the foregoing method embodiments. The processors and transceivers described in this application may be implemented on integrated circuits (INTEGRATED CIRCUIT, ICs), analog ICs, radio frequency integrated circuits RFICs, mixed signal ICs, application SPECIFIC INTEGRATED Circuits (ASICs), printed circuit boards (printed circuit board, PCBs), terminals, and the like. The processor and transceiver may also be fabricated using a variety of IC process technologies such as complementary metal oxide semiconductor (complementary metal oxide semiconductor, CMOS), N-type metal oxide semiconductor (NMOS), P-type metal oxide semiconductor (PMOS), bipolar junction transistor (bipolar junction transistor, BJT), bipolar CMOS (BiCMOS), silicon germanium (SiGe), gallium arsenide (GaAs), etc.

The scope of the communication device described in the present application is not limited thereto, and the structure of the communication device may not be limited by fig. 11. The communication apparatus 1100 may be a stand-alone device or may be part of a larger device. For example, the communication device 1100 may be:

(1) A stand-alone integrated circuit IC, or chip, or a system-on-a-chip or subsystem;

(2) A set of one or more ICs, optionally including storage means for storing data, a computer program;

(3) An ASIC, such as a Modem (Modem);

(4) Modules that may be embedded within other devices;

(5) Receivers, terminals, smart terminals, cellular telephones, wireless devices, handsets, mobile units, vehicle devices, network devices, cloud devices, artificial intelligence devices, etc.;

(6) Others, and so on.

As a possible product form, any network element (for example, the beidou ground receiving station 31, the beidou ground transmitting station 35, the signal receiving processing device 32, the signal processing center 33, the signal sending processing device 36, the operation control center 37 and the beidou short message fusion communication platform 34) in the beidou network device 200 in the embodiment of the present application may be implemented by a general bus architecture.

Referring to fig. 12, fig. 12 is a schematic structural diagram of a communication device 1200 according to an embodiment of the present application. The communication device 1200 may be the Beidou network device 200, or a device therein. As shown in fig. 12, the communication device 1200 includes a processor 1201 and a transceiver 1202 in communication with the processor internal connection. The processor 1201 is a general-purpose processor, a special-purpose processor, or the like. For example, a baseband processor or a central processing unit for satellite communications. The baseband processor of satellite communications may be used to process satellite communications protocols and satellite communications data, and the central processor may be used to control communications devices (e.g., baseband chips, etc.), execute computer programs, and process data for the computer programs. The transceiver 1202 may be referred to as a transceiver unit, transceiver circuitry, or the like, for implementing a transceiver function. The transceiver 1202 may include a receiver, which may be referred to as a receiver or a receiving circuit, etc., for implementing a receiving function; the transmitter may be referred to as a transmitter or a transmitting circuit, etc., for implementing a transmitting function. Optionally, the communication device 1200 may further comprise an antenna 1203 and/or a radio frequency unit (not illustrated). The antenna 1203 and/or radio frequency unit may be located inside the communication device 1200 or may be separate from the communication device 1200, i.e. the antenna 1203 and/or radio frequency unit may be remotely located or distributed.

Optionally, the communication device 1200 may include one or more memories 1204, on which instructions may be stored, which may be a computer program that may be executed on the communication device 1200, such that the communication device 1200 performs the method described in the method embodiments above. Optionally, the memory 1204 may also store data. The communication device 1200 and the memory 1204 may be provided separately or may be integrated.

Wherein the processor 1201, the transceiver 1202, and the memory 1204 may be connected by a communication bus.

In one design, the communication apparatus 1200 may be configured to perform the functions of the beidou network device 200 in the foregoing embodiment: processor 1201 may be configured to perform the functional steps described above with respect to protocol parsing and encapsulation and operational determination performed by Beidou network device 200 in the embodiment illustrated in FIG. 7 and/or other processes for the techniques described herein; the transceiver 1202 may be configured to perform the functional steps of protocol parsing and encapsulation and operational determination performed by the Beidou network device 200 in the embodiments illustrated in FIGS. 4, 6 and 7 and/or other processes for the techniques described herein.

In either of the designs described above, a transceiver for implementing the receive and transmit functions may be included in the processor 1201. For example, the transceiver may be a transceiver circuit, or an interface circuit. The transceiver circuitry, interface or interface circuitry for implementing the receive and transmit functions may be separate or may be integrated. The transceiver circuit, interface or interface circuit may be used for reading and writing codes/data, or the transceiver circuit, interface or interface circuit may be used for transmitting or transferring signals.

In any of the above designs, the processor 1201 may have instructions stored therein, which may be a computer program, running on the processor 1201, may cause the communication apparatus 1200 to perform the method steps performed by the terminal 100 in the above method embodiments. The computer program may be solidified in the processor 1201, in which case the processor 1201 may be implemented in hardware.

The embodiments of the present application also provide a computer readable storage medium having stored therein computer program code which, when executed by the above-mentioned processor, causes a communication device to perform the method of any of the previous embodiments.

Embodiments of the present application also provide a computer program product which, when run on a computer, causes the computer to perform the method of any of the preceding embodiments.

The embodiment of the application also provides a communication device which can exist in the form of a chip product, and the structure of the device comprises a processor and an interface circuit, wherein the processor is used for communicating with other devices through a receiving circuit, so that the device executes the method in any of the previous embodiments.

The embodiment of the application also provides a Beidou communication system, which comprises the terminal 100 and the Beidou network equipment 200, wherein the terminal 100 and the Beidou network equipment 200 can execute the method in any of the previous embodiments.

The application introduces the communication function of the short message in the Beidou communication system, and can be understood that the communication function supporting the short message can also exist in other satellite systems. Therefore, the method is not limited to the Beidou communication system, and the method is also applicable to the communication of other satellite systems if other satellite systems also support the communication function of short messages.

The above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the application.

As used in the above embodiments, the term "when …" may be interpreted to mean "if …" or "after …" or "in response to determination …" or "in response to detection …" depending on the context. Similarly, the phrase "at the time of determination …" or "if detected (a stated condition or event)" may be interpreted to mean "if determined …" or "in response to determination …" or "at the time of detection (a stated condition or event)" or "in response to detection (a stated condition or event)" depending on the context.

In the above embodiments, it may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When loaded and executed on a computer, produces a flow or function in accordance with embodiments of the present application, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable apparatus. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by a wired (e.g., coaxial cable, fiber optic, digital subscriber line), or wireless (e.g., infrared, wireless, microwave, etc.). The computer readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that contains an integration of one or more available media. The usable medium may be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid state disk), etc.

Those of ordinary skill in the art will appreciate that implementing all or part of the above-described method embodiments may be accomplished by a computer program to instruct related hardware, the program may be stored in a computer readable storage medium, and the program may include the above-described method embodiments when executed. And the aforementioned storage medium includes: ROM or random access memory RAM, magnetic or optical disk, etc.

Claims

1. A mail downloading and inquiring method in a Beidou communication system is characterized by comprising the following steps:

the method comprises the steps that a first terminal sends a mail downloading query request message to north-fighting network equipment, wherein the mail downloading query request message is used for downloading the content of a mail sent to the first terminal by one or more second terminals, the mail downloading query request message comprises a message ID field, the message ID field is used for indicating the ID of a first mail which is successfully received last time by the first terminal, and the ID of the first mail is used for indicating the Beidou network equipment to delete the first mail;

The first terminal receives a letter downloading inquiry result message sent by the Beidou network equipment; the mail downloading inquiry result message comprises a mail content field and a mail ID field; the letter content field is used for indicating the content of a second letter sent to the first terminal by the one or more second terminals, the letter ID field is used for indicating the ID of the second letter, the ID of the second letter and the ID of the first letter are arranged in sequence, and the ID of the second letter is arranged behind the ID of the first letter.

2. The method according to claim 1, wherein the letter download query request message further includes a service type field, and wherein in the case that the service type field is a first value, the service type field is used to indicate that the letter download query request message is used to download content of a second letter sent to the first terminal by a second terminal in a whitelist;

The service type field is used for indicating the letter downloading inquiry request message to be used for downloading the content of a second letter sent to the first terminal by the second terminal in a non-white list under the condition that the service type field is a second value;

the service type field is used for indicating the letter downloading inquiry request message to be used for downloading the contents of the second letters sent to the first terminal by all the second terminals under the condition that the service type field is a third value;

The first terminal is provided with the white list, and the white list is used for storing an identification of a second terminal associated with the first terminal and a serial number of the second terminal associated with the first terminal.

3. The method of claim 2, wherein the step of determining the position of the substrate comprises,

The mail downloading inquiry request message further comprises a first sender ID field, wherein the first sender ID field is used for indicating the sequence number of the second terminal in a white list under the condition that the service type field is the first value;

and if the service type field is the second value, the mail downloading inquiry request message further comprises a first sender ID field, wherein the first sender ID field is used for indicating the identification of a second terminal in a non-white list.

4. The method of claim 3, wherein the letter download query result message further comprises a whitelist indication field, a second sender ID field;

The white list indication field is used for indicating the mobile phone number of the second terminal in the non-white list in the second sender ID field under the condition that the white list indication field is a fourth value;

and under the condition that the white list indication field is a fifth value, the white list indication field is used for indicating that the second sender ID field is a serial number of the second terminal in a white list.

5. The method of claim 4, wherein the letter download query result message further includes a message type indication field, and wherein the message type indication field is used to indicate that the letter download query result message is used to indicate the number of second letters sent by the one or more second terminals to the first terminal if the message type indication field is a sixth value;

And in the case that the message type indication field is a seventh value, the message type indication field is used for indicating that the letter download inquiry result message is used for indicating the content of the second letters sent to the first terminal by the one or more second terminals.

6. The method of claim 5, wherein in the case where the traffic type in the letter download query result message is the first value, the whitelist indication field in the letter download query result message is the fifth value, and the message type indication field in the letter download query result message is the seventh value;

And in the case that the service type in the mail downloading query request message is the second value, the whitelist indication field in the mail downloading query result message is the fourth value, and the message type indication field in the mail downloading query result message is the seventh value.

7. The method of claim 2, wherein the letter download query result message further comprises a letter download complete indication field; the mail downloading completion indication field is used for indicating whether a mail sent by the second terminal to the first terminal exists after the Beidou network equipment sends the second mail or not under the condition that the service type field is a first value or a second value; and under the condition that the service type field is a third value, the letter downloading completion indication field is used for indicating whether all letters sent by the second terminal to the first terminal exist after the Beidou network equipment sends the second letters.

8. The method of claim 7, wherein the letter download query result message further comprises an original message transmission time field for indicating an original transmission time of the second letter.

9. The method of claim 8, wherein the letter download query result message further comprises a location information indicator field; and when the position information indication field is a ninth value, the position information indication field is used for indicating that the position information field exists in the subsequent field.

10. The method of claim 9, wherein in the case where the location information indicator field is a ninth value, the letter download query result message further includes a location information field; the location information field is used to indicate the location information of the second terminal indicated by the sender ID field.

11. The method of any of claims 1-10, wherein the letter download query result message further comprises a data format indication field for indicating a format of the content of the second letter.

12. The method of claim 11, wherein before the first terminal sends the letter download inquiry request message to the north-fighting network device, the method further comprises:

the first terminal detects a first operation and generates a mail downloading inquiry request message based on the first operation.

13. The method of claim 12, wherein the first terminal sending a letter download query request message to a north-fighting network device, comprises:

The first terminal transmits the letter downloading inquiry request message to a message data convergence MDCP layer of the first terminal at an application APP layer, and the message data convergence MDCP layer is used as an MDCP service data unit SDU of the MDCP layer;

The first terminal adds the MDCP SDU into filling data and redundant length indication fields and then splits the MDCP SDU into one or more MDCP protocol data units PDU; the one or more MDCP PDUs comprise a first MDCP PDU;

the first terminal transmits the first MDCP PDU to a satellite link control SLC layer to serve as an SLC SDU of the SLC layer;

the first terminal splits the SLC SDU into one or more SLC PDUs;

And the first terminal sends the one or more SLC PDUs to the Beidou network equipment.

14. The method of claim 13, wherein the first terminal receiving the letter download query result message sent by the beidou network device includes:

The first terminal receives P SLC PDUs sent by the Beidou network equipment; the P is a positive integer;

The first terminal composes the P SLC PDUs into Q SLC SDUs at the SLC layer; q is a positive integer, and Q is smaller than or equal to P;

the first terminal uploads the Q SLC SDUs to the MDCP layer to serve as Q MDCP PDUs of the MDCP layer;

The first terminal splices the Q MDCP PDUs into MDCP SDUs at the MDCP layer;

And the first terminal uploads the MDCP SDU to the application APP layer after removing the filling data and the redundant length indication field by the MDCP layer, and takes the MDCP SDU as a mail downloading query result message.

15. The method of claim 14, wherein after the first terminal receives the letter download query result message sent by the beidou network device, the method further comprises:

the first terminal analyzes the content of the second letters of the first terminal, which is sent by one or more second terminals in the letter content field in the letter downloading inquiry result message;

The first terminal displays the content of the second letter in a display screen.

16. A mail downloading and inquiring method in a Beidou communication system is characterized by comprising the following steps:

The method comprises the steps that Beidou network equipment receives a mail downloading query request message sent by a first terminal, wherein the mail downloading query request message is used for downloading the content of a mail sent by one or more second terminals to the first terminal, the mail downloading query request message comprises a message ID field, the message ID field is used for indicating the ID of a first mail which is successfully received last time by the first terminal, and the ID of the first mail is used for indicating the Beidou network equipment to delete the first mail;

Based on the mail downloading query request message, the Beidou network equipment generates a mail downloading query result message, wherein the mail downloading query result message comprises a mail content field and a mail ID field; the letter content field is used for indicating the content of a second letter sent to the first terminal by the one or more second terminals, the letter ID field is used for indicating the ID of the second letter, the ID of the second letter is arranged in sequence with the ID of the first letter, and the ID of the second letter is arranged behind the ID of the first letter;

and the Beidou network equipment sends a letter downloading query result message to the first terminal.

17. The method of claim 16, wherein the mail download query message further comprises a service type field, and wherein the service type field is used to indicate that the mail download query message is used to download content of a second mail sent by a second terminal in a whitelist to the first terminal if the service type field is a first value;

18. The method of claim 17, wherein the step of determining the position of the probe is performed,

In the case that the service type field is the first value, the mail downloading query request message further includes a first sender ID field, where the first sender ID field is a whitelist bitmap, and a first bit of the whitelist bitmap is used to indicate an identifier of a second terminal with a first sequence number in a whitelist;

And under the condition that the service type field is the second value, the mail downloading inquiry request message further comprises a first sender ID field, wherein the first sender ID field is used for indicating the mobile phone number of the second terminal in the non-white list.

19. The method of claim 18, wherein the letter download query result message further comprises a whitelist indication field, a second sender ID field;

The white list indication field is used for indicating the identification of the second terminal which is in the non-white list in the second sender ID field under the condition that the white list indication field is a fourth value;

and under the condition that the white list indication field is a fifth value, the white list indication field is used for indicating that the second sender ID field is a serial number of a second terminal in a white list.

20. The method of claim 19, wherein the letter download query result message further includes a message type indication field, and wherein the message type indication field is used to indicate that the letter download query result message indicates a number of second letters sent by the one or more second terminals to the first terminal if the message type indication field is a sixth value;

And in the case that the message type indication field is a seventh value, the message type indication field is used for indicating that the letter download inquiry result message indicates the content of the second letters sent to the first terminal by the one or more second terminals.

21. The method of claim 20, wherein in the case where the traffic type in the letter download query result message is the first value, the whitelist indication field in the letter download query result message is the fifth value, and the message type indication field in the letter download query result message is the seventh value;

and under the condition that the service type in the mail downloading query request message is the second value, the white list indication field in the mail downloading query result message is the fourth value, and the message type indication field in the mail downloading query result message is the seventh value.

22. The method of claim 17, wherein the letter download query result message further comprises a letter download complete indication field; the mail downloading completion indication field is used for indicating whether a mail sent by the second terminal to the first terminal exists after the Beidou network equipment sends the second mail or not under the condition that the service type field is a first value or a second value; and under the condition that the service type field is a third value, the letter downloading completion indication field is used for indicating whether all letters sent by the second terminal to the first terminal exist after the Beidou network equipment sends the second letters.

23. The method of claim 22, wherein the letter download query result message further comprises an original message transmission time field, the original message transmission time field indicating an original transmission time of the second letter.

24. The method of claim 23, wherein the letter download query result message further comprises a location information indicator field; and when the position information indication field is a ninth value, the position information indication field is used for indicating that the position information field exists in the subsequent field.

25. The method of claim 24, wherein in the case where the location information indicator field is a ninth value, the letter download query result message further includes a location information field; the location information field is used to indicate the location information of the second terminal indicated by the sender ID field.

26. The method of any of claims 16-25, wherein the letter download query result message further comprises a data format indication field for indicating a format of the content of the second letter.

27. The method of claim 26, wherein the receiving, by the beidou network device, the letter download query request message sent by the first terminal includes:

The Beidou network equipment receives X satellite link control layer protocol data units (SLC PDUs) sent by the first terminal; x is a positive integer;

the Beidou network equipment composes the X SLC PDUs into Y SLC service data units SDU at an SLC layer; y is a positive integer, and is less than or equal to X;

The Beidou network equipment uploads the Y SLC SDUs to a message data aggregation MDCP layer to serve as Y MDCP PDUs of the MDCP layer;

The Beidou network equipment splices the Y MDCP PDUs into MDCP SDUs at the MDCP layer;

And the Beidou network equipment uploads the MDCP SDU to an application APP layer after removing the filling data and the redundant length indication field by the MDCP layer, and takes the MDCP SDU as a mail downloading query request message.

28. The method of claim 27, wherein the generating, by the beidou network device, a letter download query result message based on the letter download query request message comprises:

The Beidou network equipment inquires the content of the second letters sent to the first terminal by the one or more second terminals after the sending time of the first letters in a short message center according to the letter downloading inquiry request message;

And the Beidou network equipment generates a letter downloading query result message based on the content of the second letter.

29. The method of claim 28, wherein the sending, by the beidou network device, a letter download query result message to the first terminal includes:

The Beidou network equipment downloads the letter downloading query result message to a message data convergence MDCP layer of the Beidou network equipment at an application APP layer, and the message data convergence MDCP layer is used as an MDCP service data unit SDU of the MDCP layer;

the Beidou network equipment adds the MDCP SDU into filling data and redundant length indication fields and then splits the MDCP SDU into one or more MDCP protocol data units PDU; the one or more MDCP PDUs comprise a second MDCP PDU;

the Beidou network equipment transmits the second MDCP PDU to a satellite link control SLC layer to serve as an SLC SDU of the SLC layer;

The Beidou network equipment splits the SLC SDU into one or more SLC PDUs;

And the Beidou network equipment sends the one or more SLC PDUs to the first terminal.

30. The method of claim 29, wherein after the beidou network device transmits the one or more SLC PDUs to the first terminal, the method further comprises:

And the Beidou network equipment receives confirmation information sent by the first terminal, wherein the confirmation information is used for indicating the first terminal to collect the SLC SDU.

31. The method of claim 30, wherein in a case where the letter download complete indication field of the letter download query result message indicates that there is a letter to be sent to the first terminal after the letter download query result message, the Beidou network device receives the confirmation information sent by the first terminal, the method further comprises:

the Beidou network equipment generates a letter sending indication message at the SLC layer, wherein the letter sending indication message is used for indicating the application APP layer to send the content of a third letter;

And sending the indication message based on the letters, wherein the Beidou network equipment sends the content of the third letters at the application APP layer.

32. The Beidou communication system is characterized by comprising a first terminal and Beidou network equipment; wherein:

The first terminal is configured to send a letter download query request packet to a beidou network device, where the letter download query request packet is configured to download contents of letters sent by one or more second terminals to the first terminal, and the letter download query request packet includes a message ID field, where the message ID field is configured to indicate an ID of a first letter that was received successfully by the first terminal last time, and the ID of the first letter is configured to indicate the beidou network device to delete the first letter;

The Beidou network equipment is used for receiving a mail downloading query request message sent by a first terminal;

The Beidou network equipment is used for generating a mail downloading query result message based on the mail downloading query request message, wherein the mail downloading query result message comprises a mail content field and a mail ID field; the letter content field is used for indicating the content of a second letter sent to the first terminal by the one or more second terminals after the sending time of the first letter, the letter ID field is used for indicating the ID of the second letter, the ID of the second letter is arranged in sequence with the ID of the first letter, and the ID of the second letter is arranged after the ID of the first letter;

The first terminal is used for receiving a letter downloading query result message sent by the Beidou network equipment.

33. A communications device comprising one or more processors, one or more memories, and a transceiver; wherein the transceiver, the one or more memories are coupled to the one or more processors, the one or more memories for storing computer program code comprising computer instructions that, when executed by the one or more processors, cause the communications apparatus to perform the method of any of claims 1-15.

34. The communication device of claim 33, wherein the communication device is a terminal.

35. A communication device comprising one or more processors, one or more memories, and a transceiver; wherein the transceiver, the one or more memories are coupled to the one or more processors, the one or more memories for storing computer program code comprising computer instructions that, when executed by the one or more processors, cause the communications apparatus to perform the method of any of claims 16-31.

36. The communication apparatus of claim 35, wherein the communication apparatus is a beidou network device.

37. A computer readable storage medium having instructions stored therein which, when run on a computer, cause the computer to perform the method of any of claims 1-15.

38. A computer readable storage medium having instructions stored therein which, when run on a computer, cause the computer to perform the method of any of claims 16-31.

39. A chip for a terminal, comprising processing circuitry and interface circuitry, the interface circuitry to receive code instructions and to transmit to the processing circuitry, the processing circuitry to execute the code instructions to perform the method of any of claims 1-15.