A Satellite Network Mobility Management Method Based on Pre-Interaction

Abstract

The present invention discloses a satellite network mobility management method based on pre-interaction, which includes: the target satellite sending a downlink frequency band announcement packet to the user with successful access; the user listening to the satellite pilot frequency band and sending an uplink status report packet to the target satellite; after receiving the packet, the target satellite sending a handover request packet to the target neighbor satellite; after receiving the packet, when the remaining resources meet the user allocation requirements, the target neighbor satellite sending a handover response packet representing successful allocation to the target satellite; after receiving the packet, the target satellite sending a downlink handover command packet to the user; the user accessing a target neighbor satellite based on the downlink handover command packet and sending an information update packet to the location manager, carrying the message of the updated access satellite in the information update packet sent to the peer user; and judging the completion situation of the update by parsing the update response packets sent by the location manager and the peer user. The present invention can reduce the conflict during user access, save the overhead of sending update signaling to the peer, reduce the handover delay, and reduce the packet loss during the handover process.

Description

Technical Field

[0001] The present invention belongs to the technical field of satellite mobile communication, and particularly relates to a satellite network mobility management method based on pre-interaction. Background Art

[0002] In a LEO satellite constellation network, due to the wide satellite coverage, relatively short distance from the ground, and high moving speed, ground users based on satellite communication will frequently switch between the coverage areas of different satellites. Therefore, mobility management is required to solve the problem of discontinuous communication caused by handovers.

[0003] The commonly used mobility management methods in satellite communication systems mainly include the Mobile IP protocol and improved methods based on the Mobile IP protocol. The main idea of the Mobile IP protocol is that the end user applies for and obtains a home address at the home agent. When the user moves to an external network, the user applies for and obtains a care-of address from the foreign agent. When the user communicates in the home network, the home address is used. When communicating in the external network, the care-of address is bound to the home address by sending a binding update to the home agent. When sending data, it is sent based on the home address, and when receiving data, the data is obtained through the tunnel between the home agent and the foreign agent forwarded by the home agent.

[0004] In scenarios where the communication duration between the end user and the peer is relatively long, there are obvious deficiencies in using the Mobile IP protocol for mobility management: First, the protocol does not consider the access conflict problem that may occur when the user randomly accesses the foreign agent at the data link layer when switching to a new network; Second, the handover process needs to complete four parts: random access, application for a new address, binding update, and routing optimization. The handover delay is relatively large, affecting the continuity of data transmission and reception; Third, each time the user switches, the user needs to apply for a new address from the foreign agent and send a binding update to the home agent. When the handover is frequent, the overhead is relatively large.

[0005] The improved methods based on the Mobile IP protocol include the Hierarchical Mobile IP protocol, the Fast Mobile IP protocol, and the Proxy Mobile IP protocol, etc. The Hierarchical Mobile IP protocol distinguishes between local handovers and foreign handovers, and effectively reduces the signaling overhead in the network by introducing a mobile anchor to handle local handover problems, but there are certain limitations when applied to dynamic network topologies; In the Fast Mobile IP protocol, the end user pre-generates a new address by itself, effectively reducing the delay of applying for a new address during the handover process, but at the same time introducing the signaling overhead of interaction between the new satellite and the old satellite; The Proxy Mobile IP protocol mainly introduces a local mobile anchor and a mobile access gateway to relieve the signaling interaction of the user terminal in the mobility management solution, and is applicable to scenarios where the user terminal capabilities are limited. Although the above improved methods based on the Mobile IP protocol have made certain improvements in terms of handover delay or signaling overhead, there are still problems such as not considering the conflicts during access and limited application scenarios. Summary of the Invention

[0006] To solve the above problems existing in the prior art, the present invention provides a satellite network mobility management method based on pre-interaction. The technical problems to be solved by the present invention are realized through the following technical solutions:

[0007] The target satellite sends a downlink frequency band announcement packet to the user who has completed the access work;

[0008] After receiving and parsing the downlink frequency band announcement packet, the user continuously monitors the pilot frequency bands of the target satellite and its neighboring satellites, and determines whether to send an uplink status report packet to the target satellite according to the comparison of the monitored pilot signal strengths; wherein, the uplink status report packet indicates the target neighboring satellite of the target satellite, and the pilot signal strength of the target neighboring satellite is greater than that of the target satellite;

[0009] The target satellite determines whether to send a handover request packet to the target neighboring satellite according to whether it receives the uplink status report packet;

[0010] If the target neighboring satellite receives the handover request packet, it determines the type of handover response packet to be sent to the target satellite according to whether its remaining resources can meet the allocation requirements of the user;

[0011] The target satellite determines whether to send a downlink handover command packet to the user according to the type of handover response packet received;

[0012] The user determines the method of accessing the target neighboring satellite according to whether it receives the downlink handover command packet; and sends an information update packet to the location manager after successful access; and, the user determines the format of the information update packet to be sent to the peer user according to whether there are uplink data packets waiting to be sent and completes the sending;

[0013] After receiving and parsing the information update packet sent by the user, the location manager updates the mapping relationship table and sends an update response packet to the user;

[0014] After receiving and parsing the information update packet in any format sent by the user, the peer user updates the user information table, and determines the format of the update response packet to be returned to the user according to whether there are uplink data packets waiting to be sent to the user and completes the sending;

[0015] The user determines the update completion situation according to whether it receives the update response packets sent by the location manager and the peer user and the corresponding formats.

[0016] In an embodiment of the present invention, determining whether to send an uplink status report packet to the target satellite according to the monitored pilot signal strength includes:

[0017] The user determines whether there is a target neighbor satellite among the neighbor satellites of the target satellite whose pilot signal strength is greater than that of the target satellite according to the monitored pilot signal strength;

[0018] If there is, it is determined whether there is an uplink data packet waiting to be sent to the target satellite; if so, the user first sends an uplink status report packet to the target satellite and then sends the uplink data packet; if not, the user directly sends an uplink status report packet to the target satellite; wherein, the uplink status report packet carries the user's identity information, the identity information of the target satellite, and a satellite list containing the target neighbor satellite;

[0019] If not, it is determined whether there is an uplink data packet waiting to be sent to the target satellite; if so, the user only sends an uplink data packet to the target satellite; if not, no sending operation is performed.

[0020] In an embodiment of the present invention, the target satellite determines whether to send a handover request packet to the target neighbor satellite according to whether it receives the uplink status report packet, including:

[0021] If the target satellite receives the uplink status report packet, it parses the uplink status report packet to obtain the user's identity information and the satellite list, and sends a handover request packet to the target neighbor satellite in the satellite list; wherein, in the handover request packet, the identity information of the user about to switch to the target neighbor satellite and the user's requested resource information are carried;

[0022] If the target satellite does not receive the uplink status report packet, no handover request packet is sent.

[0023] In an embodiment of the present invention, if the target neighbor satellite receives the handover request packet, it determines the type of handover response packet to be sent to the target satellite according to whether its remaining resources can meet the allocation requirements of the user, including:

[0024] If the remaining resources on the target neighbor satellite can meet the allocation requirements of the user, the target neighbor satellite pre-allocates resources for the user, parses the user's identity information from the handover request packet, the target neighbor satellite records the user's identity information and the resources allocated for the user in the resource allocation table, and returns a handover response packet indicating successful allocation to the target satellite;

[0025] If the remaining resources on the target neighbor satellite cannot meet the allocation requirements of the user, the target neighbor satellite returns a handover response packet indicating non - allocation to the target satellite;

[0026] Among them, the handover response packet carries the identity information of the user, the flag indicating whether the user is successfully allocated, and the resource information corresponding to the successfully allocated user.

[0027] In an embodiment of the present invention, the target satellite determines whether to send a downlink handover command packet to the user according to the received handover response packet type, including:

[0028] If the target satellite receives a handover response packet indicating successful allocation, parses it to obtain the identity information of the user, the flag indicating whether the user is successfully allocated, and the resource information corresponding to the successfully allocated user, updates the handover user information table stored in the target satellite, and sends a downlink handover command packet to the user; among them, the handover user information table contains the identity information of the users who initiate the status report and successfully obtain the resources allocated by the target neighbor satellite, and the identity information of the corresponding target neighbor satellite; the downlink handover command packet carries the identity information of the user, the flag indicating whether the user is successfully allocated, and the resource information corresponding to the successfully allocated user;

[0029] If the target satellite receives a handover response packet indicating non - allocation, no further processing is performed.

[0030] In an embodiment of the present invention, the user determines the method of accessing the target neighbor satellite according to whether the downlink handover command packet is received, including:

[0031] If the user does not receive the downlink handover command packet, the user determines the handover moment according to the relative signal strength between the target satellite and the target neighbor satellite, and randomly accesses a target neighbor satellite based on contention during handover;

[0032] If the user receives the downlink handover command packet, the user immediately accesses the specified target neighbor satellite without conflict based on the resource information in the downlink handover command packet.

[0033] In an embodiment of the present invention, the user determines the format of the information update packet sent to the peer user and completes the sending according to whether there is an uplink data packet waiting to be sent, including:

[0034] If the user has an uplink data packet waiting to be sent, carry an update flag in the uplink data packet, merge the information update packet sent to the peer user and the uplink data packet, and send it to the peer user in the user information table; among them, the user information table contains the identity information of the peer users who communicate with the user recently and the identity information of the satellites accessed by the peer users;

[0035] If the user has no uplink data packet waiting to be sent, directly send an information update packet to the peer user; wherein, the format types of the information update packets sent by the user include information update packets and uplink data packets carrying update identifiers; the information update packets sent by the user to the peer user carry the user's identity information and the user's current access satellite identity information.

[0036] In an embodiment of the present invention, after receiving and parsing the information update packet sent by the user, the location manager updates the mapping relationship table and sends an update response packet to the user, including:

[0037] After receiving the information update packet sent by the user, the location manager parses to obtain the user identity identifier and access satellite information, updates the mapping relationship table and sends an update response packet to the user; wherein, the mapping relationship table contains the identity information of all users in the whole network, as well as the user's current access satellite identity information; the update response packet sent by the location manager carries the location manager's identity information and access satellite identity information.

[0038] In an embodiment of the present invention, after receiving and parsing the information update packet of any format sent by the user, the peer user updates the user information table, and determines the format of the update response packet to be returned to the user and completes the sending according to whether there is an uplink data packet waiting to be sent to the user, including:

[0039] After receiving the information update packet or the uplink data packet carrying the update identifier sent by the user, the peer user parses to obtain the user's identity information and access satellite identity information, and updates the stored user information table;

[0040] When the peer user has an uplink data packet waiting to be sent to the user, carry the update identifier in the uplink data packet, merge the update response packet to be sent to the user and the uplink data packet, and send them to the user;

[0041] When the peer user has no uplink data packet waiting to be sent to the user, send an update response packet to the user; wherein, the format types of the update response packets sent by the peer user include update response packets and uplink data packets carrying update identifiers; the update response packets sent by the peer user carry the peer user's identity information and access satellite identity information.

[0042] In an embodiment of the present invention, the user determines the update completion situation according to whether it receives the update response packets sent by the location manager and the peer user and the corresponding formats, including:

[0043] If the format type of the update response packet sent by the peer user received by the user is an update response packet, it indicates that the user information table stored by the peer user has been updated successfully;

[0044] If the format type of the update response packet sent by the peer user received by the user is an uplink data packet carrying an update identifier, and the update identifier in the uplink data packet is successfully updated, it indicates that the user information table stored by the peer user has been updated successfully;

[0045] If the format type of the update response packet sent by the peer user received by the user is an uplink data packet carrying an update identifier, and the update identifier in the uplink data packet is not updated, it indicates that the user information table stored by the peer user has not been updated completely. Then the user continues to send an information update packet or an uplink data packet carrying an update identifier to the peer user;

[0046] If the user does not receive an update response packet of any format type sent by the peer user, it indicates that the user information table stored by the peer user has not been updated completely. Then the user continues to send an information update packet or an uplink data packet carrying an update identifier to the peer user;

[0047] If the user receives the update response packet sent by the location manager, it indicates that the mapping relationship table stored by the location manager has been updated successfully;

[0048] If the user does not receive the update response packet sent by the location manager, it indicates that the mapping relationship table stored by the location manager has not been updated completely. Then the user continues to send an information update packet to the location manager.

[0049] The solution provided by the embodiments of the present invention has the following advantages compared with the prior art:

[0050] First, through the pre-interaction mechanism in the embodiments of the present invention, before the current user switches to the newly accessed satellite, the user can apply for resources from the newly accessed satellite through the forwarding of the old accessed satellite. During the actual handover, the conflict-free access process is completed based on the pre-applied resources, which overcomes the problem in the prior art that resources must be applied for from the newly accessed satellite during the handover, avoids the possible conflicts when accessing the new satellite, and reduces the handover delay;

[0051] Second, by storing the handover user information table on the old accessed satellite in the embodiments of the present invention, the data packets sent to the old accessed satellite during the handover can be forwarded to the newly accessed satellite by looking up the table. The current handover user does not need to send binding update messages to the peer user and the location manager during the handover, which reduces the handover delay and packet loss during the handover;

[0052] Thirdly, in the embodiments of the present invention, by carrying an update mechanism, when the current user sends an information update packet to the peer user, it can be achieved by carrying an update identifier in the data packet sent to the peer user. When the peer user replies with an update response packet, it can also be achieved by carrying an update completion identifier in the data packet sent to the current user. The current user does not need to separately send an information update or an update response packet, reducing the signaling overhead. Brief Description of the Drawings

[0053] Figure 1 It is a schematic flowchart of a satellite network mobility management method based on pre-interaction provided by an embodiment of the present invention;

[0054] Figure 2 It is a schematic diagram of the composition of the satellite network in an embodiment of the present invention;

[0055] Figure 3 It is a schematic flowchart of another satellite network mobility management method based on pre-interaction provided by an embodiment of the present invention. Detailed Embodiments

[0056] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0057] The purpose of the embodiments of the present invention is to propose a satellite network mobility management method based on pre-interaction in view of the deficiencies of the prior art, to avoid conflicts when the user terminal accesses a new satellite, reduce the access delay during the handover process, and reduce the signaling overhead for binding updates when the user makes a handover.

[0058] As Figure 1 shown, a satellite network mobility management method based on pre-interaction provided by an embodiment of the present invention may include the following steps:

[0059] S1, the target satellite sends a downlink frequency band announcement packet to the user who has completed the access work;

[0060] The satellite network scenario of the embodiments of the present invention relates to a low-earth orbit satellite network, which may include multiple satellites and users, as well as a location manager. Among them, the users in the embodiments of the present invention refer to ground users, and the satellites may be LEO satellites. The target satellite refers to the satellite that has completed the access work with the user, and the user who has completed the access work refers to the user who first accesses the target satellite and establishes a connection with the target satellite through random access.

[0061] The downlink frequency band announcement packet carries the pilot frequency band information of multiple neighbor satellites of the target satellite. Specifically, the downlink frequency band announcement packet includes multiple neighbor satellite identity fields and neighbor satellite pilot information fields.

[0062] S2. After the user receives and parses the downlink frequency band announcement packet, the user continuously monitors the pilot frequency bands of the target satellite and its neighbor satellites, and determines whether to send an uplink status report packet to the target satellite according to the comparison of the monitored pilot signal strengths.

[0063] After the user receives the downlink frequency band announcement packet, the user parses to obtain the pilot frequency band information of the neighbor satellites of the target satellite, and starts to continuously monitor the pilot frequency bands of the target satellite and its neighbor satellites.

[0064] Among them, determining whether to send an uplink status report packet to the target satellite according to the comparison of the monitored pilot signal strengths includes:

[0065] The user determines whether there is a target neighbor satellite among the neighbor satellites of the target satellite whose pilot signal strength is greater than that of the target satellite according to the monitored pilot signal strength.

[0066] If there is, it is determined whether there is an uplink data packet waiting to be sent to the target satellite; if so, the user first sends an uplink status report packet to the target satellite and then sends the uplink data packet; if not, the user directly sends an uplink status report packet to the target satellite.

[0067] If there is none, it is determined whether there is an uplink data packet waiting to be sent to the target satellite; if so, the user only sends the uplink data packet to the target satellite; if not, no sending operation is performed.

[0068] Among them, the uplink status report packet indicates the target neighbor satellite of the target satellite, and the pilot signal strength of the target neighbor satellite is greater than that of the target satellite. Specifically, the uplink status report packet carries the user's identity information, the target satellite's identity information, and a satellite list containing the target neighbor satellite. Among them, the user's identity information is represented by the user's identity identification field; the satellite list is represented by the neighbor satellite list field.

[0069] It can be understood that the number of target neighbor satellites in the satellite list may be more than one.

[0070] S3. The target satellite determines whether to send a handover request packet to the target neighbor satellite according to whether it receives the uplink status report packet.

[0071] This step specifically includes:

[0072] If the target satellite receives the uplink status report packet, it parses the uplink status report packet to obtain the identity information of the user and the satellite list, and sends a handover request packet to the target neighbor satellite in the satellite list;

[0073] Among them, in the handover request packet, the identity information of the user who is about to hand over to the target neighbor satellite and the user's requested resource information are carried. Specifically, the handover request packet includes a user identity identification field and a user requested resource field.

[0074] If the target satellite does not receive the uplink status report packet, it does not send a handover request packet, that is, it does not perform the next step of processing.

[0075] S4. If the target neighbor satellite receives the handover request packet, it determines the type of handover response packet to be sent to the target satellite according to whether its remaining resources can meet the allocation requirements of the user;

[0076] This step specifically includes:

[0077] If the remaining resources on the target neighbor satellite can meet the allocation requirements of the user, the target neighbor satellite first parses the identity information of the user from the handover request packet, then pre-allocates resources for the user. The target neighbor satellite records the identity information of the user and the resource information allocated for the user in the resource allocation table, and returns a handover response packet indicating successful allocation to the target satellite; The handover response packet indicating successful allocation means that the resource allocation field is "yes" and the resource content field contains the resource information pre-allocated by the target neighbor satellite for the user.

[0078] If the remaining resources on the target neighbor satellite cannot meet the allocation requirements of the user, the target neighbor satellite returns a handover response packet indicating non-allocation to the target satellite; The handover response packet indicating non-allocation means that the resource allocation field is "no" and the resource content field is "no resource information".

[0079] Among them, the remaining resources on a satellite refer to the idle physical resources such as beams, channels, and frequencies currently owned by the satellite and available for accessing users.

[0080] Among them, the handover response packet carries the identity information of the user, the identification of whether the user is successfully allocated, and the resource information corresponding to the successfully allocated user. Specifically, the handover response packet includes a user identity identification field, a resource allocation field, and a resource content field.

[0081] S5. The target satellite determines whether to send a downlink handover command packet to the user according to the type of handover response packet received;

[0082] This step specifically includes:

[0083] If the target satellite receives a handover response packet indicating successful allocation, it parses the packet to obtain the user's identity information, the flag indicating whether the user is successfully allocated, and the resource information corresponding to the successfully allocated user, updates the handover user information table stored in the target satellite, and sends a downlink handover command packet to the user;

[0084] Among them, the handover user information table contains the identity information of users who initiate a status report and successfully obtain resources allocated by the target neighbor satellite, and the identity information of the corresponding target neighbor satellite; specifically, the handover user information table contains a user identity identification field and an access satellite identity identification field.

[0085] The downlink handover command packet carries the user's identity information, the flag indicating whether the user is successfully allocated, and the resource information corresponding to the successfully allocated user. Specifically, the downlink handover command packet contains a user identity identification field and a resource content field, and the downlink handover command packet designates a single target neighbor satellite to be accessed by the user.

[0086] If the target satellite receives a handover response packet indicating non-allocation, no further processing is performed.

[0087] S6. The user determines the method of accessing the target neighbor satellite according to whether the downlink handover command packet is received; and sends an information update packet to the location manager after successful access; and, the user determines the format of the information update packet to be sent to the peer user according to whether there is an uplink data packet waiting to be sent and completes the sending;

[0088] Among them, the user determines the method of accessing the target neighbor satellite according to whether the downlink handover command packet is received, including:

[0089] If the user does not receive the downlink handover command packet, the user determines the handover moment according to the relative signal strength between the target satellite and the target neighbor satellite, and randomly accesses a target neighbor satellite based on contention during handover; specifically, the handover moment refers to the moment when the signal strength of the target neighbor satellite is greater than that of the target satellite, and the signal strength of the target satellite is about to drop to 0. At the handover moment, the user sends an access request to each target neighbor satellite in the neighbor satellite list field of the previously sent uplink status report packet. After receiving the request, the target neighbor satellite will send a response to the user, and the user will complete the access process with the target neighbor satellite corresponding to the first received feedback response.

[0090] If the user receives the downlink handover command packet, the user immediately accesses the specified target neighbor satellite without conflict based on the resource information in the downlink handover command packet.

[0091] In S6, the information update packet sent by the user to the location manager after successful access carries the user's identity information and the identity information of the satellite accessed by the user, specifically including the user's identity identification field and the identity identification field of the accessed satellite.

[0092] In S6, the user determines the format of the information update packet sent to the peer user according to whether there is an uplink data packet waiting to be sent and completes the sending, including:

[0093] If the user has an uplink data packet waiting to be sent, an update identifier is carried in the uplink data packet, and the information update packet sent to the peer user and the uplink data packet are merged and sent to the peer user in the user information table;

[0094] If the user has no uplink data packet waiting to be sent, the information update packet is directly sent to the peer user.

[0095] Among them, merging and sending the information update packet sent to the peer user and the uplink data packet means that the update identifier field in the uplink data packet is a request for update.

[0096] The user information table contains the identity information of the peer users who have communicated with the user recently and the identity information of the satellites accessed by the peer users, specifically including the user's identity identification field and the identity identification field of the accessed satellite.

[0097] The format types of the information update packets sent by the user include information update packets and uplink data packets carrying update identifiers; the information update packets sent by the user to the peer users carry the user's identity information and the current satellite access identity information of the user, specifically including the user's identity identification field and the identity identification field of the accessed satellite.

[0098] In S7, after receiving and parsing the information update packet sent by the user, the location manager updates the mapping relationship table and sends an update response packet to the user;

[0099] This step specifically includes:

[0100] After receiving the information update packet sent by the user, the location manager parses to obtain the user identity identification and satellite access information, updates the mapping relationship table and sends an update response packet to the user;

[0101] Among them, the mapping relationship table contains the identity information of all users in the whole network and the current satellite access identity information of the users; specifically, the mapping relationship table contains the user's identity identification field and the identity identification field of the accessed satellite.

[0102] The update response packet sent by the location manager carries the identity information of the location manager and the identity information of the access satellite. Specifically, the update response packet sent by the location manager includes an identity identification field of the location manager and an identity identification field of the access satellite.

[0103] S8. After the peer user parses the information update packet in any format sent by the user, it updates the user information table, and determines the format of the update response packet to be returned to the user and completes the sending according to whether there is an uplink data packet waiting to be sent to the user;

[0104] This step specifically includes:

[0105] After the peer user receives the information update packet or the uplink data packet carrying the update identifier sent by the user, it parses to obtain the identity information of the user and the identity information of the access satellite, and updates the stored user information table;

[0106] When the peer user has an uplink data packet waiting to be sent to the user, it carries the update identifier in the uplink data packet, merges the update response packet to be sent to the user and the uplink data packet, and sends them to the user;

[0107] When the peer user has no uplink data packet waiting to be sent to the user, it sends an update response packet to the user;

[0108] Among them, merging and sending the update response packet to be sent to the user and the uplink data packet means that the update identifier field in the uplink data packet is a successful update.

[0109] The format types of the update response packet sent by the peer user include an update response packet and an uplink data packet carrying an update identifier; the update response packet sent by the peer user carries the identity information of the peer user and the identity information of the access satellite; specifically, the update response packet sent by the peer user includes an identity identification field of the user and an identity identification field of the access satellite.

[0110] S9. The user determines the update completion status according to whether it receives the update response packets sent by the location manager and the peer user and the corresponding formats.

[0111] This step specifically includes:

[0112] If the format type of the update response packet received by the user from the peer user is an update response packet, it indicates that the user information table stored by the peer user has been updated;

[0113] If the format type of the update response packet sent by the peer user received by the user is an uplink data packet carrying an update identifier, and the update identifier in the uplink data packet is successfully updated, it indicates that the user information table stored by the peer user has been updated;

[0114] If the format type of the update response packet sent by the peer user received by the user is an uplink data packet carrying an update identifier, and the update identifier in the uplink data packet is not updated, it indicates that the user information table stored by the peer user has not been updated. Then the user continues to send an information update packet or an uplink data packet carrying an update identifier to the peer user;

[0115] If the user does not receive an update response packet of any format type sent by the peer user, it indicates that the user information table stored by the peer user has not been updated. Then the user continues to send an information update packet or an uplink data packet carrying an update identifier to the peer user;

[0116] If the user receives the update response packet sent by the location manager, it indicates that the mapping relationship table stored by the location manager has been updated;

[0117] If the user does not receive the update response packet sent by the location manager, it indicates that the mapping relationship table stored by the location manager has not been updated. Then the user continues to send an information update packet to the location manager.

[0118] The solution provided by the embodiments of the present invention has the following advantages compared with the prior art:

[0119] First, through the pre-interaction mechanism in the embodiments of the present invention, before the current user switches to a newly accessed satellite, the user can apply for resources from the newly accessed satellite through the forwarding of the old accessed satellite. During the actual handover, the conflict-free access process is completed based on the pre-applied resources, overcoming the problem in the prior art that resources must be applied for from the newly accessed satellite during the handover, avoiding the possible conflicts when accessing the new satellite, and reducing the handover delay;

[0120] Second, by storing the handover user information table on the old accessed satellite in the embodiments of the present invention, the data packets sent to the old accessed satellite during the handover can be forwarded to the newly accessed satellite by looking up the table. The current handover user does not have to send binding update messages to the peer user and the location manager during the handover, reducing the handover delay and reducing the packet loss during the handover;

[0121] Thirdly, in the embodiments of the present invention, by carrying an update mechanism, when the current user sends an information update packet to the peer user, it can be achieved by carrying an update identifier in the data packet sent to the peer user. When the peer user replies with an update response packet, it can also be achieved by carrying an update completion identifier in the data packet sent to the current user. The current user does not need to separately send an information update or an update response packet, reducing the signaling overhead.

[0122] The following combines Figure 2 the schematic diagram of the satellite network composition of the example and Figure 3 another flowchart of the satellite network mobility management method provided based on pre-interaction. This figure shows the detailed process, and based on this figure, the satellite network mobility management method based on pre-interaction will be specifically described.

[0123] From Figure 2 it can be seen that the satellite network scenario of the embodiments of the present invention includes 2 LEO satellites, 2 ground users, and 1 location manager. User and satellite access and handover are performed in this satellite network scenario. Among them, the 2 LEO satellites are satellite A and satellite Y respectively; the neighbor satellites of satellite A include satellite X, satellite Y, satellite M, and satellite N; the 2 ground users are user a and user b respectively. Please refer to Figure 3 to understand the detailed process of the satellite network mobility management method based on pre-interaction.

[0124] Step 1, after user a randomly accesses satellite A, satellite A sends a downlink frequency band announcement packet to user a.

[0125] The downlink frequency band announcement packet contains the pilot frequency band information of the neighbor satellites of satellite A, namely satellite X, satellite Y, satellite M, and satellite N.

[0126] Step 2, user a starts to monitor the signal strength of the pilot frequency bands of satellite A and its neighbor satellites.

[0127] Specifically, after receiving the downlink frequency band announcement packet, user a parses the satellite information and the corresponding pilot frequency band information in the downlink frequency band announcement packet, and monitors the pilot frequency bands of satellite A and its neighbor satellites.

[0128] Specifically, user node a monitors the pilot frequency bands of satellite A, satellite X, satellite Y, satellite M, and satellite N.

[0129] Step 3, user a determines whether to send an uplink status report packet to satellite A.

[0130] User a decides whether to send an uplink status report packet to satellite A by comparing the pilot signal strengths of satellite A and its neighbor satellites monitored. Specifically:

[0131] If user a monitors that the pilot signal strength of satellite A is greater than that of its neighboring satellites, and user a has uplink data packets waiting to be sent to satellite A, then user a does not send an uplink status report packet to satellite A, but only sends uplink data packets;

[0132] If user a monitors that the pilot signal strength of satellite A is less than that of at least one neighboring satellite, and user a has uplink data packets waiting to be sent to satellite A, then user a first sends an uplink status report packet to satellite A and then sends uplink data packets;

[0133] For example, in this embodiment, after user a monitors that the pilot signal strength of satellite Y is greater than that of satellite A, user a sends an uplink status report packet to satellite A. At this time, only one target neighboring satellite, satellite Y, is included in the satellite list in the uplink status report packet.

[0134] Step 4, satellite A decides whether to send a handover request packet to a neighboring satellite.

[0135] Satellite A decides whether to send a handover request packet to a certain neighboring satellite according to whether it receives an uplink status report packet. Specifically:

[0136] If satellite A receives the uplink status report packet sent by user a, it parses the user identity information and satellite list in the uplink status report packet, and sends a handover request packet to the target neighboring satellite in the satellite list;

[0137] If satellite A does not receive the uplink status report packet sent by user a, it does not perform the next step of processing.

[0138] Specifically, in the example of this embodiment of the present invention, satellite A receives the uplink status report packet sent by user a, parses the satellite list in the packet as satellite Y, and satellite A forms a handover request packet and sends it to satellite Y.

[0139] Step 5, satellite Y determines the type of handover response packet to be sent to satellite A.

[0140] As the target neighboring satellite, satellite Y determines the type of handover response packet to be sent to satellite A according to whether the remaining resources on its own satellite can meet the allocation requirements of user a. Specifically:

[0141] If the remaining resources on satellite Y can meet the allocation requirements of user a, then satellite Y pre-allocates resources for user a, records the identity information of user a and the resource information allocated for user a in the resource allocation table, and returns a "successful allocation" handover response packet to the current satellite node, that is, a handover response packet representing successful allocation;

[0142] If the remaining resources on the neighboring satellite node cannot meet the allocation requirements of the current user, the neighboring satellite node returns an "unallocated" handover response packet to the current satellite node, that is, a handover response packet indicating unallocation.

[0143] In the example of the embodiment of the present invention, after receiving the handover request packet, satellite Y parses the user a identity information and requested resource information in the packet, pre-allocates resources for user a after access grant judgment, updates the resource allocation table stored on its own satellite, adds the corresponding entry for user a, and returns a "successfully allocated" handover response packet to satellite A.

[0144] Step 6, satellite A decides whether to send a downlink handover command packet to user a.

[0145] Satellite A decides whether to send a handover command packet to user a according to the type of the received handover response packet. Specifically:

[0146] If satellite A receives a "successfully allocated" handover response packet, parses the user node identity information for user a, the flag indicating whether the user node is successfully allocated, and the resource information corresponding to the successfully allocated user node, updates the handover user information table stored on its own satellite, and sends a downlink handover command packet to user a;

[0147] If satellite A receives an "unallocated" handover response packet, no further processing is performed;

[0148] In the example of the embodiment of the present invention, satellite A receives a "successfully allocated" handover response packet, parses the user node a identity information, the flag indicating that user node a is successfully allocated, and the resource information corresponding to user node a, updates the handover user information table stored on its own satellite, adds the corresponding entry for user node a, and sends a downlink handover command packet to user node a.

[0149] Step 7, user a determines the way to access satellite Y.

[0150] User a determines the way to access satellite Y according to whether a downlink handover command packet is received. Specifically:

[0151] If user a does not receive a downlink handover command packet, the handover moment is determined according to the relative signal strength between satellite A and all target neighboring satellites, and a target neighboring satellite node is randomly accessed based on contention during handover;

[0152] If user a receives a downlink handover command packet, it immediately accesses the specified only one target neighboring satellite without conflict based on the resource information in the downlink handover command packet;

[0153] In the example of the embodiment of the present invention, user a receives a downlink handover command packet, parses the successfully allocated information for user a and the corresponding resource information, and starts to access satellite Y based on the pre-allocated resources.

[0154] Step 8, user a sends an information update packet to the location manager.

[0155] Specifically, in the example of the embodiment of the present invention, after user a successfully accesses satellite Y, user a sends an information update packet to the location manager.

[0156] Step 9, user a determines the format of the information update packet to be sent to peer user b.

[0157] User a determines the format of the information update packet to be sent to peer user b in the user information table according to whether there is an uplink data packet waiting to be sent to peer user b. Specifically:

[0158] If user a has an uplink data packet waiting to be sent to peer user b, an update identifier is carried in the uplink data packet, and the information update packet sent to peer user b is carried in the uplink data packet and sent together.

[0159] If user a does not have an uplink data packet waiting to be sent to peer user b, an information update packet is directly sent to peer user b.

[0160] In the example of the embodiment of the present invention, user node a has an uplink data packet waiting to be sent to peer user b, so the update identifier field of the uplink data packet is set to 1 and then sent to user b, indicating that the satellite node accessed by user a has been updated.

[0161] Step 10, the location manager sends an update response packet to user a.

[0162] In the example of the embodiment of the present invention, after receiving the information update packet, the location manager parses to obtain the identity information of user a and the identity information of the accessed satellite node, updates the stored mapping relation table, and sends an update response packet to user a.

[0163] Step 11, peer user b determines the way to send an update response packet to user a.

[0164] After receiving the information update packet or the uplink data packet carrying the update identifier, peer user b parses to obtain the identity information of the user node for user a and the identity information of the accessed satellite node, updates the stored user information table, and determines the way to send an update response packet to user a according to whether there is an uplink data packet waiting to be sent to user a. Specifically:

[0165] If peer user b has an uplink data packet waiting to be sent to user a, an update identifier is carried in the uplink data packet, and the update response packet sent to user a is carried in the uplink data packet and sent together.

[0166] If peer user b does not have an uplink data packet waiting to be sent to user a, an update response packet is directly sent to user a.

[0167] In the example of the embodiment of the present invention, after user b receives the uplink data packet carrying the update identifier, user b parses to obtain the identity identifier of user a, the access satellite identity identifier, and the update identifier. User b updates the corresponding entry of user a in the stored user information table, and sets the update identifier field in the uplink data packet sent to user a to 2, indicating that the update is completed.

[0168] Step 12, user a determines the update completion status.

[0169] User a determines the update completion status of user b according to whether it receives the uplink data packet or the update response packet carrying the update identifier sent by user b. Specifically:

[0170] If user a receives the update response packet sent by user b, it indicates that the user information table stored by user b as the peer user has been updated successfully;

[0171] If user a receives the uplink data packet carrying the update identifier sent by user b, and the update identifier in the uplink data packet is successfully updated, it indicates that the user information table stored by user b has been updated successfully;

[0172] If user a receives the uplink data packet carrying the update identifier sent by user b, and the update identifier in the uplink data packet is not updated, it indicates that the update of the user information table stored by user b is not completed, and user a needs to resend the information update packet or the uplink data packet carrying the update identifier to user b;

[0173] If user a does not receive the uplink data packet or the update response packet carrying the update identifier sent by user b, it indicates that the update of the user information table stored by user b is not completed, and user a needs to resend the information update packet or the uplink data packet carrying the update identifier to user b;

[0174] In the example of the embodiment of the present invention, user a receives the uplink data packet carrying the update identifier sent by user b, parses to obtain the identity identifier of user b, the access satellite identity identifier, and the update identifier. The update identifier value of 2 indicates that the update of user b is completed.

[0175] User a determines the update completion status of the location manager according to whether it receives the update response packet sent by the location manager. Specifically:

[0176] If user a receives the update response packet sent by the location manager, it indicates that the mapping relationship table stored by the location manager has been updated;

[0177] If user a does not receive the update response packet sent by the location manager, it indicates that the mapping relationship table stored by the location manager is not updated, and user a needs to continue to send the information update packet to the location manager.

[0178] In the example of the embodiment of the present invention, user a receives the update response packet sent by the location manager, indicating that the mapping relation table stored in the location manager has been updated.

[0179] For the specific content and related effects, please refer to the relevant content described above.

[0180] The above are only the preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention are all included in the protection scope of the present invention.

Claims

1. A satellite network mobility management method based on pre-interaction, characterized in that, Including: The target satellite sends a downlink frequency band announcement packet to the user who has completed the access work; After receiving and parsing the downlink frequency band announcement packet, the user continuously monitors the pilot frequency bands of the target satellite and its neighboring satellites, and determines whether to send an uplink status report packet to the target satellite according to the comparison of the monitored pilot signal strengths; wherein, the uplink status report packet specifies the target neighboring satellite of the target satellite, and the pilot signal strength of the target neighboring satellite is greater than that of the target satellite; The target satellite determines whether to send a handover request packet to the target neighboring satellite according to whether the uplink status report packet is received; If the target neighboring satellite receives the handover request packet, it determines the type of handover response packet to be sent to the target satellite according to whether its remaining resources can meet the allocation requirements of the user; The target satellite determines whether to send a downlink handover command packet to the user according to the type of handover response packet received, including: if the target satellite receives a handover response packet indicating successful allocation, it parses the identity information of the user, the flag indicating whether the user is successfully allocated, and the resource information corresponding to the successfully allocated user, updates the handover user information table stored in the target satellite, and sends a downlink handover command packet to the user; wherein, the handover user information table contains the identity information of the user who initiates the status report and successfully obtains the resources allocated by the target neighboring satellite, and the identity information of the corresponding target neighboring satellite; the downlink handover command packet carries the identity information of the user, the flag indicating whether the user is successfully allocated, and the resource information corresponding to the successfully allocated user; The user determines the method of accessing the target neighbor satellite according to whether the downlink handover command packet is received; and sends an information update packet to the location manager after successful access; and, the user determines the format of the information update packet sent to the peer user according to whether there is an uplink data packet waiting to be sent and completes the sending; wherein, the user determines the method of accessing the target neighbor satellite according to whether the downlink handover command packet is received, including: if the user receives the downlink handover command packet, the user immediately accesses the specified target neighbor satellite without conflict based on the resource information in the downlink handover command packet; the user determines the format of the information update packet sent to the peer user according to whether there is an uplink data packet waiting to be sent and completes the sending, including: if the user has an uplink data packet waiting to be sent, an update identifier is carried in the uplink data packet, and the information update packet sent to the peer user and the uplink data packet are merged and sent to the peer user in the user information table; wherein, the user information table contains the identity information of the peer user who has communicated with the user recently and the identity information of the satellite to which the peer user is connected; if the user has no uplink data packet waiting to be sent, an information update packet is directly sent to the peer user; wherein, the format types of the information update packet sent by the user include an information update packet and an uplink data packet carrying an update identifier; the information update packet sent by the user to the peer user carries the user's identity information and the identity information of the satellite to which the user is currently connected; After receiving and parsing the information update packet sent by the user, the location manager updates the mapping relationship table and sends an update response packet to the user; After receiving and parsing the information update packet of any format sent by the user, the peer user updates the user information table and determines the format of the update response packet returned to the user according to whether there is an uplink data packet waiting to be sent to the user and completes the sending, including: when the peer user has an uplink data packet waiting to be sent to the user, an update identifier is carried in the uplink data packet, and the update response packet sent to the user and the uplink data packet are merged and sent to the user; The user determines the update completion status according to whether the update response packets sent by the location manager and the peer user are received and the corresponding formats.

2. The satellite network mobility management method based on pre-interaction according to claim 1, wherein The determination of whether to send an uplink status report packet to the target satellite according to the comparison of the monitored pilot signal strengths includes: The user judges whether there is a target neighbor satellite among the neighbor satellites of the target satellite whose pilot signal strength is greater than that of the target satellite according to the monitored pilot signal strength; If there is, it is judged whether there is an uplink data packet waiting to be sent to the target satellite; if so, the user first sends an uplink status report packet to the target satellite and then sends the uplink data packet; if not, the user directly sends an uplink status report packet to the target satellite; wherein, the uplink status report packet carries the user's identity information, the identity information of the target satellite, and a satellite list containing the target neighbor satellite; If not, determine whether there is an uplink data packet waiting to be sent to the target satellite; if so, the user only sends the uplink data packet to the target satellite; if not, no sending operation is performed.

3. The satellite network mobility management method based on pre-interaction according to claim 2, characterized in that The target satellite determines whether to send a handover request packet to the target neighbor satellite based on whether it receives the uplink status report packet, including: If the target satellite receives the uplink status report packet, parse the uplink status report packet to obtain the user's identity information and satellite list, and send a handover request packet to the target neighbor satellite in the satellite list; wherein, in the handover request packet, the identity information of the user who is about to switch to the target neighbor satellite and the user's requested resource information are carried. If the target satellite does not receive the uplink status report packet, no handover request packet is sent.

4. The satellite network mobility management method based on pre-interaction according to claim 3, wherein If the target neighbor satellite receives the handover request packet, determine the type of handover response packet sent to the target satellite according to whether its remaining resources can meet the allocation requirements of the user, including: If the remaining resources on the target neighbor satellite can meet the allocation requirements of the user, the target neighbor satellite pre-allocates resources for the user, and parses the user's identity information from the handover request packet. The target neighbor satellite records the user's identity information and the resource information allocated for the user in the resource allocation table, and returns a handover response packet indicating successful allocation to the target satellite. If the remaining resources on the target neighbor satellite cannot meet the allocation requirements of the user, the target neighbor satellite returns a handover response packet indicating non-allocation to the target satellite. Among them, the handover response packet carries the user's identity information, the identifier of whether the user is successfully allocated, and the resource information corresponding to the successfully allocated user.

5. The satellite network mobility management method based on pre-interaction according to claim 4, characterized in that, The target satellite determines whether to send a downlink handover command packet to the user according to the type of the received handover response packet, and also includes: If the target satellite receives a handover response packet indicating non-allocation, no further processing is performed.

6. The method for satellite network mobility management based on pre-interaction according to claim 5, wherein The user determines the method of accessing the target neighbor satellite according to whether it receives the downlink handover command packet, and also includes: If the user does not receive the downlink handover command packet, the user determines the handover moment according to the relative signal strength between the target satellite and the target neighbor satellite, and randomly accesses a target neighbor satellite based on contention during handover.

7. The method for satellite network mobility management based on pre-interaction according to claim 6, wherein After receiving and parsing the information update packet sent by the user, the location manager updates the mapping relationship table and sends an update response packet to the user, including: After receiving the information update packet sent by the user, the location manager parses to obtain the user identity identifier and access satellite information, updates the mapping relationship table and sends an update response packet to the user; wherein, the mapping relationship table contains the identity information of all users in the whole network and the identity information of the access satellite where the user is currently located; the update response packet sent by the location manager carries the identity information of the location manager and the identity information of the access satellite.

8. The method for satellite network mobility management based on pre-interaction according to claim 7, wherein After parsing the information update packet in any format sent by the user, the peer user updates the user information table, and determines the format of the update response packet to be returned to the user and completes the sending according to whether there is an uplink data packet waiting to be sent to the user. It further includes: After receiving the information update packet or the uplink data packet carrying the update identifier sent by the user, the peer user parses to obtain the user's identity information and the access satellite identity information, and updates the stored user information table; When there is no uplink data packet waiting to be sent to the user, the peer user sends an update response packet to the user; wherein, the format types of the update response packet sent by the peer user include an update response packet and an uplink data packet carrying the update identifier; the update response packet sent by the peer user carries the peer user's identity information and the access satellite identity information.

9. The method for satellite network mobility management based on pre-interaction according to claim 8, wherein The user determines the update completion status according to whether it receives the update response packets sent by the location manager and the peer user and the corresponding formats, including: If the format type of the update response packet received by the user from the peer user is an update response packet, it indicates that the user information table stored by the peer user has been updated; If the format type of the update response packet received by the user from the peer user is an uplink data packet carrying the update identifier, and the update identifier in the uplink data packet is successfully updated, it indicates that the user information table stored by the peer user has been updated; If the format type of the update response packet received by the user from the peer user is an uplink data packet carrying the update identifier, and the update identifier in the uplink data packet is not updated, it indicates that the user information table stored by the peer user has not been updated, then the user continues to send an information update packet or an uplink data packet carrying the update identifier to the peer user; If the user does not receive an update response packet of any format type sent by the peer user, it indicates that the user information table stored by the peer user has not been updated, then the user continues to send an information update packet or an uplink data packet carrying the update identifier to the peer user; If the user receives the update response packet sent by the location manager, it indicates that the mapping relation table stored by the location manager has been updated; If the user does not receive the update response packet sent by the location manager, it indicates that the mapping relation table stored by the location manager has not been updated, then the user continues to send an information update packet to the location manager.

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