A satellite return link resource allocation method and device

Abstract

The present application discloses a satellite return link resource allocation method and device, the method comprising: determining the priority of each user terminal and the service information corresponding to each service request according to at least one service request sent by at least one user terminal; allocating return link resources to each service request according to the service information and the priority. The present application solves the technical problem of the lack of a solution for return link resource allocation in the prior art.

Description

Technical Field

[0001] The present application relates to the field of satellite communication technology, and in particular to a method and device for allocating satellite return link resources. Background Art

[0002] The research on satellite network resource management is mainly aimed at call access control and resource management issues in various dimensions. The research on call access control is responsible for designing access control judgment criteria based on certain network management goals to determine whether a connection request is allowed or denied access. Resource management optimizes the allocation of various types of resources in the network among various beams or user terminals. At present, related research mainly discusses on-board resource optimization schemes from the perspectives of frequency domain, time domain and power domain to improve the communication performance of satellite systems. However, current research is still mainly based on bandwidth allocation and power control of the forward link, lacking research on the existing return link MF-TDMA system and actual system constraints and targeted resource allocation algorithm design. At the same time, compared with narrowband satellite communication systems, the types of user terminals and the types of services carried by broadband satellite communication systems are more diverse. It is necessary to distinguish the user terminal capabilities, service requirements and user terminal priorities of different user terminals, and provide differentiated service guarantees for user terminals with different priorities. However, when considering the priority of user terminals and services, there is no recognized standard for the service quality guarantee of each service request, and the comprehensive assessment of the priority of service requests in the network is still an open problem. Summary of the invention

[0003] The technical problem solved by this application is: in view of the lack of a solution for return link resource allocation in the prior art, this application provides a satellite return link resource allocation method and device. In the solution provided by the embodiment of this application, the user priority and service type are taken into consideration at the same time, and differentiated service quality guarantees can be provided for users of different priorities and different services of users of the same priority. At the same time, it can also take into account the balance between user priority and system communication performance.

[0004] In a first aspect, an embodiment of the present application provides a satellite return link resource allocation method, the method comprising:

[0005] Determining the priority of each user terminal and service information corresponding to each service request according to at least one service request sent by at least one user terminal;

[0006] Return link resources are allocated to each service request according to the service information and the priority.

[0007] Optionally, the service information includes a service type and a transmission rate, wherein the service type includes a real-time service, a non-real-time service, and a best-effort service;

[0008] The priorities are, in descending order, the first priority, the second priority and the third priority.

[0009] Optionally, allocating a return link resource to each service request according to the service information and the priority includes:

[0010] Determine, according to the priority and the service type, an allocation order of return link resources for each user terminal and / or at least one service request corresponding to each user terminal;

[0011] Return link resources are allocated to each service request according to the allocation order.

[0012] Optionally, the allocation order is: the service corresponding to the user terminal with the first priority, the service with the second priority and the service type is real-time service, the service with the third priority and the service type is real-time service, the service with the second priority and the service type is non-real-time service, the service with the third priority and the service type is non-real-time service, the service with the second priority or the third priority and the service type is best-effort service.

[0013] Optionally, allocating a return link resource to each service request according to the allocation order includes:

[0014] Determine a maximum processing bandwidth corresponding to each user terminal, determine a user terminal group corresponding to each user terminal according to the maximum processing bandwidth, and determine a subcarrier group corresponding to each user terminal group according to a preset mapping relationship between the user terminal group and the subcarrier group in the return link resource, wherein each subcarrier group includes at least one subcarrier with the same bandwidth;

[0015] According to the allocation order, a return link resource is allocated to each service request of each user terminal on the subcarrier group corresponding to the user terminal in turn.

[0016] Optionally, allocating a return link resource to each service request of each user terminal in the subcarrier group corresponding to the user terminal in sequence according to the allocation order includes:

[0017] According to the size of the bandwidth of each subcarrier in the subcarrier group, the subcarrier groups corresponding to the user terminal group are sorted in order from small to large to obtain a subcarrier group sequence;

[0018] According to the subcarrier group sequence and the allocation order, return link resources are allocated to at least one service request corresponding to each user terminal on the subcarrier group corresponding to each group of user terminals in turn.

[0019] Optionally, allocating return link resources for at least one service request corresponding to each user terminal on the subcarrier group corresponding to each group of user terminals in sequence according to the subcarrier group sequence and the allocation order includes:

[0020] Determine the number of time slots required for service transmission corresponding to at least one service request of each user terminal in each group of user terminals, and determine the total number of first time slots required for user terminals of the first priority, the total number of second time slots required for user terminals of the second priority, and the total number of third time slots required for user terminals of the third priority according to the number of time slots;

[0021] Starting from the first subcarrier group of the subcarrier group sequence, allocating time slots according to the first total number of time slots for at least one service request corresponding to the user terminal of the first priority, and determining whether the sum of the second total number of time slots and the third total number of time slots is greater than the total number of time slots remaining in the first subcarrier group;

[0022] If it is greater, then return link resources are allocated to at least one service request corresponding to the user terminal of the second priority and / or the third priority in sequence according to the allocation order; until resource allocation of all subcarrier groups in the subcarrier group sequence is completed.

[0023] Optionally, allocating a time slot to at least one service request corresponding to a user terminal of a first priority according to the total number of the first time slots includes:

[0024] An equal number of time slot resources are allocated to at least one service request corresponding to the user terminal of the first priority level in each subframe in a superframe corresponding to a subcarrier.

[0025] Optionally, the return link resources allocated to each user terminal are on one subcarrier.

[0026] Optionally, allocating return link resources for at least one service request corresponding to the user terminal of the second priority and / or the third priority in sequence according to the allocation order includes: determining whether there is a second subcarrier group in which the number of idle time slots of the second subcarrier is not less than the number of time slots required by the user terminal to be currently allocated, wherein the bandwidth of the carrier in the second subcarrier group is less than the bandwidth of the subcarrier in the first subcarrier group;

[0027] If so, a return link resource is allocated on the second subcarrier for at least one service request corresponding to the user terminal currently to be allocated.

[0028] Optionally, if the second subcarrier does not exist, determining whether there is at least one service among the services corresponding to the at least one service request that can be degraded for transmission;

[0029] If there is at least one service that can be downgraded for transmission, the at least one service will be downgraded until the number of times the at least one service is downgraded reaches a preset number or the time slot required for the service transmission corresponding to the at least one service request after the downgrade is less than the remaining time slots in the subcarrier group.

[0030] Optionally, it also includes: if there is no at least one service that can be downgraded for transmission, the total number of the first time slots is less than the total number of remaining time slots, or after at least one service is downgraded, it also includes: determining the service request allocated to each subcarrier according to a modified branch and bound method.

[0031] Optionally, determining the service request allocated to each subcarrier according to a modified branch and bound method includes:

[0032] Determine a weight value and a transmission volume of a service corresponding to each service request, and calculate the value of each service according to the weight value and the transmission volume;

[0033] Determine an upper bound and a lower bound according to the value of each service and the number of remaining time slots of the subcarrier group corresponding to each group of user terminals, wherein the upper bound and the lower bound refer to the service request of the user terminal corresponding to each subcarrier and the information of the user terminal;

[0034] The service request of the user terminal and the user terminal allocated to each subcarrier are determined according to the preset constraint condition, the upper bound and the lower bound.

[0035] Optionally, the preset constraint conditions include: the time slots required for at least one service request corresponding to each user are allocated on one subcarrier; and the total value of the services corresponding to the service requests allocated on all subcarriers in each subcarrier group is the largest.

[0036] In a second aspect, an embodiment of the present application provides a satellite return link resource allocation device, the device comprising:

[0037] A determination module, determining the priority of each user terminal and the service information corresponding to each service request according to at least one service request sent by at least one user terminal received;

[0038] The resource allocation module allocates return link resources to each service request according to the service information and the priority.

[0039] Optionally, the resource allocation module includes: a highest priority user resource allocation submodule, a bandwidth adjustment submodule, a service degradation submodule, a user scheduling and subcarrier allocation submodule, and a time slot allocation submodule; wherein,

[0040] The highest priority user resource allocation submodule is used to allocate resources to the service request corresponding to the first priority user terminal with the highest priority;

[0041] The bandwidth adjustment submodule is used to adjust the service request of a user terminal to the subcarrier group with narrower bandwidth for resource allocation when the number of remaining idle time slots of a subcarrier in the subcarrier group with narrower bandwidth is not less than the number of time slots required for the service request of a user terminal;

[0042] The service degradation submodule is used to downgrade at least one service that is allowed to be transmitted at a downgraded level when the total number of time slots required for service requests of the second priority and third priority user terminals is greater than the total number of remaining idle time slots of the corresponding subcarrier groups;

[0043] The user scheduling and subcarrier allocation submodule is used to determine the relationship between the subcarrier and the service request corresponding to the user terminal;

[0044] The time slot allocation submodule is used to allocate resources to the service requests corresponding to the user terminals. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 A schematic diagram of the structure of a satellite communication system provided in an embodiment of the present application;

[0046] Figure 2 A schematic diagram of a flow chart of a satellite return link resource allocation method provided in an embodiment of the present application;

[0047] Figure 3 A schematic diagram of a subcarrier group resource allocation process provided in an embodiment of the present application;

[0048] Figure 4 A schematic diagram of planning resources within a superframe provided in an embodiment of the present application;

[0049] Figure 5 A schematic diagram of a user terminal that may initiate multiple service requests simultaneously provided by an embodiment of the present application;

[0050] Figure 6 A schematic diagram of the structure of a satellite return link resource allocation device provided in an embodiment of the present application;

[0051] Figure 7 A schematic diagram of the operation flow of a user scheduling and subcarrier allocation submodule provided in an embodiment of the present application. DETAILED DESCRIPTION

[0052] In the solutions provided in the embodiments of this application, the described embodiments are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0053] In order to better understand the above technical scheme, the technical scheme of the present application is described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present application and the specific features in the embodiments are detailed descriptions of the technical scheme of the present application, rather than limitations on the technical scheme of the present application. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments can be combined with each other.

[0054] See also Figure 1 A schematic diagram of the structure of a satellite communication system provided in an embodiment of the present application. Figure 1 In the embodiment, the satellite communication system includes at least one user terminal, a satellite and a network control center (Network Control Center, NCC); wherein each user terminal can communicate with the satellite and send at least one service request to the satellite, for example, a service transmission request such as voice, video, email or picture; after receiving at least one service request, the satellite forwards at least one service request to the network control center, and the network control center allocates return link resources for the at least one service request and sends the allocated resource status to the satellite. As an example, if the satellite provided in the embodiment of the present application has a resource allocation capability, then after receiving at least one service request, the satellite can directly allocate return link resources for at least one service request.

[0055] The following is a further detailed description of a satellite return link resource allocation method provided by an embodiment of the present application in conjunction with the accompanying drawings. The specific implementation of the method may include the following steps (the method flow is as follows: Figure 2 shown):

[0056] Step 201: Determine the priority of each user terminal and service information corresponding to each service request according to at least one service request received from at least one user terminal.

[0057] In the solution provided in the embodiment of the present application, the satellite can receive a service request sent by at least one user terminal, wherein each service request corresponds to a service, and each user terminal can send service requests for different service types. For example, the service request carries information such as service information, transmission rate, and priority of the user terminal sending the service request.

[0058] In one possible implementation, the service information includes service type and transmission rate, wherein the service type includes real-time service, non-real-time service and best effort service; the priorities are first priority, second priority and third priority in order of processing from high to low.

[0059] As an example, in the scheme provided in the embodiment of the present application, in terms of service types, the priorities of three types of user terminals and three types of services are considered; wherein, the three types of services include real-time services, non-real-time services, and best-effort services (services with extremely low QoS requirements), for example, real-time services include voice and video; non-real-time services include web browsing, picture transmission and other services; best-effort services include email, background interaction and other services with extremely low QoS requirements. In addition, real-time services and non-real-time services have several different transmission rates based on the service bit rate or audio and video quality. The scheme provided in the embodiment of the present application refers to the Digital Video Broadcasting (DVB) protocol, and supports providing two types of service guarantees for service requests of user terminals: rate guarantee and capacity guarantee; wherein, rate guarantee requires that specific time slot resources be allocated to the service in each subframe of the superframe to ensure the transmission quality of time-sensitive services; capacity guarantee only needs to ensure that sufficient time slot resources are provided in one scheduling cycle.

[0060] In terms of user terminal priority, in the scheme provided by the embodiment of the present application, the user terminals in the system are divided into three categories according to their priorities, namely, the first priority, the second priority and the third priority. For example, a={1,2,3} is used to represent the first priority, the second priority and the third priority, where the smaller the value of a is, the higher the priority. For the user terminal with the highest priority (first priority), for example, such as the head of state and the wartime command center, on the one hand, a constant rate guarantee is provided for the requirements proposed by them regardless of the service category, so as to ensure that their data can be transmitted quickly; on the other hand, when the satellite allocates time slots, it is given priority to arrange available time slots for them, that is, it has priority to choose and occupy resources. For the user terminal with the second priority (a=2), resources are allocated for the non-background services it transmits according to the QoS requirements proposed by the user terminal. For the user terminal with the lowest priority (third priority), when the system traffic is light, the QoS requirements proposed by it are guaranteed. When the system traffic is heavy and resources are scarce, the services with adaptive characteristics (QoS adjustable) are downgraded, such as transmitting videos with lower clarity, reducing the resource requirements of the user terminal for the system, so that the system resources are expected to meet the requirements of the user terminal, and all services can be scheduled.

[0061] Step 202: Allocate return link resources for each service request according to the service information and the priority.

[0062] In one possible implementation, allocating return link resources to each service request based on the service information and the priority includes: determining an allocation order of return link resources for each user terminal and / or at least one service request corresponding to each user terminal based on the priority and the service type; and allocating return link resources to each service request based on the allocation order.

[0063] In one possible implementation, the allocation order is: the service corresponding to the user terminal with the first priority, the service with the second priority and the service type is real-time service, the service with the third priority and the service type is real-time service, the service with the second priority and the service type is non-real-time service, the service with the third priority and the service type is non-real-time service, and the service with the second priority or the third priority and the service type is best-effort service.

[0064] In the solution provided in the embodiment of the present application, the priority of the user terminal and the service type are considered to provide 6 types of service request resource allocation priorities for a service request of the user terminal, as shown in the following Table 1. As an example, in the solution provided in the embodiment of the present application, when allocating resources, resources are allocated to each type of service request in the order of the priority of the user terminal requests of categories 1 to 6 in Table 1.

[0065] Table 1 User terminal request priority

[0066]

[0067]

[0068] Further, in a possible implementation, allocating return link resources for each service request according to the allocation order includes: determining a maximum processing bandwidth corresponding to each user terminal, determining a user terminal group corresponding to each user terminal according to the maximum processing bandwidth, and determining a subcarrier group corresponding to each user terminal group according to a preset mapping relationship between the user terminal group and the subcarrier group in the return link resources, wherein each subcarrier group includes at least one subcarrier with the same bandwidth; and allocating return link resources for each service request of each user terminal in the subcarrier group corresponding to the user terminal according to the allocation order.

[0069] As an example, in an actual satellite communication system, the subcarrier bandwidth of the system and the number of subcarriers of each width are determined by the configuration of the network control center NCC. Since there are heterogeneous user terminals (large stations, small stations) in the network, the maximum bandwidth supported by user terminals with different processing capabilities is different. The user terminals are divided into several user terminal groups according to their maximum processing capabilities. Among them, the service requests corresponding to the user terminals in the same group will be allocated subcarriers of the same bandwidth for service transmission. For example, the bandwidth of the subcarrier is 500K, 1M or 2M.

[0070] As another example, when the user terminal is turned on and connected to the network, it receives the network clock reference information (NCR), superframe composition table (SCT), frame composition table (FCT), broadcast configuration table (BCT), etc. broadcast by the satellite through the underlying signaling stream (L2S), completes synchronization and determines the composition configuration of the superframe and subframe, for example, the size and format of the time slot, and obtains the subcarrier width, number and time slot configuration of the superframe according to the size and format of the time slot. In the scheme provided in the embodiment of the present application, the system bandwidth is 50M, which is divided into 8 500k, 10 1M, 6 2M and 6 4M subcarriers. Each superframe consists of 8 frames, each frame contains 32 time slots, and the time length of each time slot is 3ms. Among them, 8 500k subcarriers constitute the first subcarrier group, 10 1M bandwidth subcarriers constitute the second subcarrier group, and so on. The 50M bandwidth is divided into 4 subcarrier groups. There are 64 user terminals in the network, of which 14 have a maximum processing bandwidth less than 1 MHz. The above 14 user terminals constitute the first user terminal group, and a 500 kHz subcarrier is used by default; 15 user terminals have a maximum processing bandwidth less than 2M, constituting the second user terminal group, and a 1 MHz subcarrier is used by default; 16 user terminals have a maximum processing bandwidth less than 4M, constituting the third user terminal group, and a 2 MHz subcarrier is used by default; the rest are user terminals with a maximum processing bandwidth greater than 4 MHz, constituting the fourth user terminal group, and a 4 MHz subcarrier is used by default.

[0071] For example, each group of user terminals has a number of user terminals with first priority, second priority and third priority, and each user terminal can initiate multiple services including audio and video, data transmission / web browsing, ftp file download / mail. The audio service is divided into services with rate requirements of 64k, 128k, and 256k according to the bit rate and audio quality, the video is divided into services with rate requirements of 5M, 2.5M, and 1M according to the bit rate or clarity, and the data / web browsing services are divided into services with rate requirements of 192k, 384k, and 576k. The user terminal initiates a service request to the network for each service and reports the service type and rate requirement. The user terminal adopts adaptive coding that complies with the DVB-S2 protocol.

[0072] Further, in a possible implementation, return link resources are allocated to at least one service request corresponding to each user terminal on the subcarrier group corresponding to each group of user terminals according to the subcarrier group sequence and the allocation order, including: determining the number of time slots required for service transmission corresponding to at least one service request of each user terminal in each group of user terminals, and determining the total number of first time slots required for user terminals of the first priority, the total number of second time slots required for user terminals of the second priority, and the total number of third time slots required for user terminals of the third priority according to the number of time slots; starting from the first subcarrier group of the subcarrier group sequence, allocating time slots to at least one service request corresponding to user terminals of the first priority according to the first total number of time slots, and determining whether the sum of the second total number of time slots and the third total number of time slots is greater than the total number of time slots remaining in the first subcarrier group; if greater, allocating return link resources to at least one service request corresponding to user terminals of the second priority and / or the third priority according to the allocation order; until resource allocation of all subcarrier groups in the subcarrier group sequence is completed.

[0073] See also Figure 3 , is a schematic diagram of a subcarrier group resource allocation process provided by an embodiment of the present application. Figure 3 For resource allocation of any subcarrier group, the number of time slots required for service transmission corresponding to at least one service request of each user terminal in each group of user terminals must first be determined. As an example, assume that the average rate required by service d of user terminal u is In order to meet the QoS requirements of service d, the number of time slots that need to be allocated to service d in each scheduling cycle is:

[0074]

[0075] Among them, t ud The number of time slots allocated to service d of user u; B u Indicates the subcarrier bandwidth used by user u; u represents the signal-to-interference-and-noise ratio of user u; m represents the time slot length.

[0076] When each user terminal initiates multiple service requests, the total number of time slots required by each user terminal is:

[0077]

[0078] Among them, t u The total number of time slots required for each user terminal; D u Indicates the service set corresponding to each user terminal.

[0079] Further, in a possible implementation method, time slots are allocated to at least one service request corresponding to a user terminal of a first priority based on the total number of the first time slots, including: an equal number of time slot resources are allocated to at least one service request corresponding to the user terminal of the first priority in each subframe in a superframe corresponding to a subcarrier.

[0080] Specifically, after determining the total number of time slots required by each user terminal, resources are allocated to at least one service request corresponding to the first priority (highest priority) user terminal. As an example, according to the number of remaining time slots of each subcarrier, a subcarrier that can meet the time slot requirements of the user terminal is selected, and for each service of the user terminal, the time slot requirements of the service are evenly carried in the available time slots of each subframe.

[0081] Further, in a possible implementation method, return link resources are allocated to at least one service request corresponding to the user terminal of the second priority and / or the third priority in sequence according to the allocation order, including: determining the number of remaining time slots of each subcarrier in the first subcarrier group corresponding to the user terminal to be currently allocated, and judging whether the number of remaining time slots of the first subcarrier is greater than the number of time slots; if so, allocating return link resources on the first subcarrier for at least one service request corresponding to the user terminal to be currently allocated.

[0082] Further, in a possible implementation method, return link resources are allocated to at least one service request corresponding to the user terminal of the second priority and / or the third priority in sequence according to the allocation order, including: determining whether there is a second subcarrier group whose number of idle time slots of the second subcarrier is not less than the number of time slots required by the user terminal to be currently allocated, wherein the bandwidth of the carriers in the second subcarrier group is less than the bandwidth of the subcarriers in the first subcarrier group; if so, allocating return link resources on the second subcarrier for at least one service request corresponding to the user terminal to be currently allocated.

[0083] Specifically, the number of remaining time slots V(n) in each subcarrier in the current subcarrier group is counted to determine whether the remaining time slots can meet the time slot requirements of user terminals with user terminal priorities of 2 and 3 ∑ u t u If ∑ u t u > V(n), and the current subcarrier group is not the subcarrier group with the narrowest subcarrier bandwidth, bandwidth adjustment is performed. As an example, bandwidth adjustment is to sort the user terminals by priority, and for each user terminal, determine whether a narrower subcarrier can be allocated to it according to the following principles:

[0084] a) The current subcarrier group is not the first (i.e., the narrowest) subcarrier group;

[0085] b) In the subcarrier group with narrower bandwidth, there is at least one subcarrier with idle time slot;

[0086] c) For a channel with idle time slots, the number of idle time slots is sufficient to carry all services of a user terminal in the current subcarrier group.

[0087] If all services of a user terminal can be carried by a narrower subcarrier, the user terminal is removed from the user terminal group corresponding to the current subcarrier group. The above operation is performed for each service in turn until the time slot requirements of the remaining services can be accommodated by the used time slots of the current subcarrier group, that is, where t u is the total number of time slots for user terminals, or there are no user terminals that can perform bandwidth degradation.

[0088] Further, in one possible implementation, if the second subcarrier does not exist, it is determined whether there is at least one service among the services corresponding to the at least one service request that can be downgraded for transmission; if there is at least one service that can be downgraded for transmission, the at least one service is downgraded until the at least one service is downgraded a preset number of times or the time slot required for the service transmission corresponding to the at least one service request after the downgrade is less than the remaining time slots in the subcarrier group.

[0089] In the solution provided in the embodiment of the present application, a user terminal set that is not allocated but still needs to be carried in the current subcarrier group is determined, the number of time slots required by the user terminal set and the number of idle time slots in the current subcarrier group are calculated, and it is determined whether the number of idle time slots in the current subcarrier group is not less than the number of time slots required by the user terminal set, that is, ∑ u t u ≤V(n). If ∑ u t u > V(n), bandwidth downgrade is performed. Assume that for each type of service, the user terminal requests audio and video resources of different quality or bit rate according to its capabilities and personal preferences. Different quality audio and video resources correspond to different average transmission rate requirements. In order not to excessively reduce the user terminal experience, it is stipulated that the network can downgrade the service request of each user terminal by at most two levels. Let l u Indicates the number of times the user terminal has been downgraded, that is, when a user terminal request has been transmitted using the lowest rate, or the user terminal has been downgraded twice, the service will no longer be downgraded for the user terminal. Record the downgraded user terminals and services, and update the average transmission rate and time slot requirements for the service.

[0090] As an example, in the solution provided in the embodiment of the present application, the return link resource (time slot) allocated to each user terminal is on one superframe or subcarrier. Figure 4 As shown, the satellite or network management center NCC needs to plan the resources within a superframe based on the current subcarrier and time slot system configuration and the service request of the user terminal currently received in the superframe. Figure 4 Two superframes are shown, namely superframe 1 and superframe 2, and the two superframes have the same size. In addition, each superframe includes multiple subframes, and each subframe includes multiple time slots; wherein, the service corresponding to the highest priority user, real-time service 1, non-real-time service and best-effort service are allocated on superframe 1, and real-time service 2 is allocated on superframe 2. It should be understood that the superframe provided in the embodiment of the present application refers to the channel with a specific bandwidth in the time domain, and the subcarrier is the channel with a specific bandwidth in the frequency domain.

[0091] Specifically, broadband satellite networks have a variety of user terminals in actual applications, with different sizes and capabilities. In addition to personal user terminals, there are also large-scale site or router-type user terminals with larger calibers and stronger capabilities. These user terminals aggregate the service requests and transmission streams of multiple small or personal user terminals, and uniformly request communication resources from the satellite. At the same time, with the enhancement of satellite user terminal processing capabilities and the intelligence of operating systems, user terminals can also initiate multiple non-conflicting services at the same time and transmit services in parallel. Therefore, considering more practical application scenarios, user terminals in the system may initiate multiple service requests at the same time, as follows Figure 5 shown.

[0092] For each service, the user terminal initiates a service request to the satellite. In order to avoid power fallback of the user terminal, the user terminal cannot work on two subcarriers at the same time, that is, multiple services initiated by each user terminal need to be carried by the same subcarrier. Therefore, although the satellite receives a request for each service, in the scenario where the user terminal has multiple services, the service requests are not independent of each other. The multiple service requests initiated by the same user terminal are coupled with each other, which increases the difficulty of the satellite's resource allocation decision. In order to take into account the user terminal priority and the network transmission rate, the weighted rate sum is still used as the optimization target. The return link time-frequency resource allocation problem in the user terminal multi-service scenario can be modeled as:

[0093]

[0094]

[0095] or

[0096] Among them, D u is the service request set of user terminal u, The binary variable, whether the service d of the user terminal u is selected by the subcarrier n, is the core decision variable of this problem. ^ is an AND operation. C1 indicates that the number of time slots required for the service carried by subchannel n does not exceed the total number of time slots in the superframe; C2 describes the constraint that the user terminal cannot transmit across channels in the scenario where some user terminals have multiple services.

[0097] question The solution algorithm is still divided into five steps: resource allocation for the highest priority user terminal, bandwidth adjustment, service degradation, user terminal scheduling and subcarrier allocation, and time slot allocation. Starting from the narrowest subcarrier group, the time slot requirements of each service of the user terminal in the group are calculated and the above five steps are performed in sequence. Then, the carrier group with the narrowest subcarrier width is selected from the remaining carrier groups, and the above operations are repeated until the resource allocation for the last subcarrier group is completed.

[0098] Assume that the average rate required by service d of user terminal u is In order to meet the QoS requirements of service d, the number of time slots that need to be allocated to service d in each scheduling cycle is:

[0099]

[0100] When a user terminal initiates multiple service requests, its total time slot requirement is:

[0101]

[0102] When the system resources are sufficient, multiple services of the user terminal can be fully served and must be transmitted in the same subcarrier; when there are too many service requests and the system resources are insufficient to meet all the service needs of the user terminal, there will be some user terminals in the system whose service requests are only partially responded to by the system, but the different services served by the same user terminal are still transmitted in the same subcarrier. In order to deal with the problem of mutual binding and coupling of multiple services of the user terminal, it is necessary to adaptively adjust the algorithm process related to user terminal scheduling, subcarrier allocation and time slot allocation. It should be noted that when each user terminal only initiates one service request, the user terminal and the service are equivalent. When the user terminal has multiple services, it is necessary to distinguish the needs of the user terminal and each service. Among them, the research object of resource allocation and bandwidth adjustment of the highest priority user terminal is the user terminal, and it is necessary to consider the sum of the time slot requirements of all services of the user terminal t uThe research object of service degradation is the service. Service degradation is performed on each service request of the user terminal. When the user terminal has multiple service requests, some of its services may be downgraded while the other services maintain the original QoS requirements.

[0103] Furthermore, in the solution provided in the embodiment of the present application, if there is not at least one service that can be downgraded for transmission, the total number of the first time slots is less than the total number of remaining time slots, or after at least one service is downgraded, it also includes: determining the service request allocated to each subcarrier according to the modified branch and bound method.

[0104] In one possible implementation, the service request assigned to each subcarrier is determined based on a modified branch and bound method, including: determining the weight value and transmission volume of the service corresponding to each service request, and calculating the value of each service based on the weight value and the transmission volume; selecting part or all of the service allocation time slot resources based on a preset first constraint condition, and calculating the total value range based on the value corresponding to the allocated service; adjusting the service allocation method based on a preset second constraint condition and the total value range until the total value corresponding to the adjusted service is maximized.

[0105] Specifically, in the solution provided in the embodiment of the present application, a set of user terminals that are not allocated but still need to be carried in the current subcarrier group is determined, as well as the average rate and number of time slots required for each service of each user terminal in the set. With the goal of maximizing the weighted rate sum of the carried services, it is determined which user terminals are carried on each subcarrier, and which services of the user terminals are carried.

[0106] In order to balance the differentiated service quality assurance of user terminals with different priorities and the communication performance of the satellite communication system, the resource allocation problem in each subcarrier group is modeled as an integer programming problem with the goal of maximizing the weighted rate sum of the service business. To further solve this problem, we equate this problem to a multi-knapsack problem. Each subcarrier can be regarded as a knapsack, and the total number of time slots on the superframe corresponding to the subcarrier corresponds to the capacity of the knapsack, i.e., V(n). Each service can be regarded as an item, and the product of the service transmission volume and the weight is defined as the value of the item, i.e., v u =w u f(R u ), where w u is the weight of the service request of each user terminal, and f(·) is a function of the transmission volume, which can be designed as f(x)=x or f(x)=log(x), etc. For simplicity, f(x)=x is taken.

[0107] Then the The problem is equivalent to: there is a set of N ibackpacks, each backpack has a size of V(n), There is a set of items The weights of the items are v u =w u f(R u ), weight is t u Find out which items should be put into which backpack so that the total value of the items in the backpack is maximized.

[0108] Furthermore, the knapsack problem can be quickly solved by the dynamic programming algorithm, but the multi-knapsack problem cannot be solved by dynamic programming alone. In order to solve the multi-knapsack problem, the solution provided in the embodiment of the present application adopts the bound-and-bound algorithm, which is a modified branch and bound algorithm. It finds the upper and lower bounds of the branch problem respectively, and performs judgment and pruning. represents the total number of remaining time slots, v u is the value of the selected item in the u-th item group, For the remaining items, is the current strategy, n is the current subcarrier number, S n is a set of services that have been determined to be carried or not carried on subcarrier n. To facilitate understanding, the modified branch and bound algorithm process involved in the embodiment of the present application is briefly introduced below.

[0109] In the solution provided in the embodiment of the present application, the modified branch-and-bound algorithm based on the multi-knapsack problem is mainly divided into four steps: initialization, heuristic algorithm, definition of current strategy and pruning. Specifically, the process of the modified branch-and-bound algorithm based on the multi-knapsack problem is as follows:

[0110] Step 1. Initialization: Find the upper bound U.

[0111] Specifically, let UB = U, the total value of the items in the backpack z = 0, and the subcarrier number n = 1. The initial backpack size is Item Collection Then use the dynamic programming algorithm to solve the item set as The 0-1 knapsack problem with a knapsack size of V, the maximum value is

[0112] Step 2. Heuristic algorithm: Find the lower bound L and determine the corresponding allocation strategy x′. The specific algorithm process is as follows:

[0113]

[0114] Step 3. Define the current policy. The specific content is as follows:

[0115]

[0116] Step 4. Pruning

[0117]

[0118]

[0119] Among them, UB represents the upper bound of the entire backpack problem; U represents the upper bound; L represents the lower bound; z represents the total value of the backpack items obtained by the most recent lower bound; represents the strategy obtained by calculating the most recent lower bound; Indicates whether subcarrier n is assigned to item u, Indicates that subcarrier n is assigned to item u, Indicates that subcarrier n is not allocated to item u; I represents the set of items allocated to subcarrier n according to the current strategy; j represents the item with the smallest number in set I; S n Indicates the set of items that have been determined to be allocated to subcarrier n or prohibited from being allocated to subcarrier n.

[0120] To facilitate understanding, the following is a brief introduction to the dynamic programming process involved in solving the upper and lower bounds.

[0121] As an example, for a service set of a user terminal u, we first use dynamic programming to solve a 0-1 knapsack problem and get dp[i][t], which represents the maximum value that can be obtained when selecting items from the first i items in a knapsack and the maximum weight does not exceed t. After a 0-1 knapsack problem, the selection of multiple services can be converted into multiple items with a weight of at most mint ud , of The value of each item is Each item is actually a subset of the original service set, that is, a combination of several selected services. At this point, the service set of each user terminal is converted into an item group. The items in each group are mutually exclusive, that is, only one item can be selected to be loaded into the backpack, and the problem is converted into a grouped backpack problem. However, since there are multiple channels at this time, the problem is still a multi-knapsack problem, so the problem is finally converted into a grouped multi-knapsack problem. Let The maximum total value of items that can be loaded into the backpack when the maximum load is t, C t Record the contents of the items put in, and the item group conversion algorithm based on dynamic programming is as follows:

[0122] Initialization: The i-th group of users to be assigned U i (including users in the second and third priority groups that are not adjusted to other subcarrier groups), service set D of user u in the user setu , the dth service in the service set and each service request u d (After service degradation) Required time slot resources t ud .

[0123]

[0124] For every user u∈U i ,from

[0125]

[0126] Remove The zero and duplicate values ​​in the , and record the corresponding C k , where C k Represents the business set corresponding to the kth item in the item group.

[0127] After conversion, multiple services of a user can be converted into a u An item group of items, each item is represented by a business subset C of user u a ,α=1,2,.,α u The weight of each item is Value At this point, the original 0-1 knapsack problem is transformed into a grouped knapsack problem. The grouped single knapsack problem can still be solved using the dynamic programming method, as shown below, where dp[t] represents the maximum total value of the items that can be loaded when the maximum load of the knapsack is t, and C t Record the selected item group and the item's group number.

[0128] Initialization: The number of available time slots for subcarrier n is V(n), dp[0,…V(n)]=0,

[0129]

[0130] The selected item is C V(n) , the corresponding item value is dp[V(n)].

[0131] Through the selected item set C V(n) It is possible to obtain the users and their service combinations C selected to be carried on subchannel n a .

[0132] Furthermore, after the knapsack problem is solved, when the user has multiple services, the time slot allocation process is still divided into two steps: non-background service and background service time slot allocation. Among them, the time slot allocation of non-background services is not affected, and each service request is still used as the operation object. For non-background services, since the user may initiate background and non-background services at the same time, and the non-background services are already carried on a certain subcarrier, the background services that have not yet been allocated time-frequency resources must also be transmitted on the subcarrier, and the subcarrier cannot be selected arbitrarily. Therefore, the time slot allocation of background services needs to take into account the allocation results of the front-end services. For each background service to be allocated, it is first necessary to determine whether the user u has initiated non-background services at the same time, and whether the user has been allocated a subcarrier. If user u only initiates a background service, the subcarrier can be selected arbitrarily for transmission. Otherwise, the background service needs to find an available time slot on the same subcarrier. If there is no available time slot, it is necessary to find out whether there is a user who meets the following conditions:

[0133] 1) The user has been assigned to subcarrier n;

[0134] 2) The user only has background services.

[0135] If there are qualified users, the relevant users can be moved to other subcarriers for transmission, thereby freeing up some resources for the background services of user u. The time slot allocation algorithm for background services in scenarios where users have multiple services is mainly divided into two situations: 1) User u has been allocated a subcarrier, that is, the user has initiated a non-background service application in addition to the background service and the system has allocated resources for the non-background service; 2) User u has not been allocated a subcarrier, that is, the user only has background services, or the user's other non-background service requests have not been responded to due to shortage of system resources. The time slot allocation algorithm for background services is shown in the following table.

[0136] Initialization: the number of remaining time slots V(n) in each subcarrier n in subcarrier group i, the set of background service requests to be allocated Q B .

[0137] Average number of time slots calculation:

[0138]

[0139]

[0140] The solution provided in the embodiment of the present application takes into account both the user priority and the service type, and can provide differentiated service quality assurance for users of different priorities and different services of users of the same priority. At the same time, it can also balance the user priority and system communication performance.

[0141] See also Figure 6A satellite return link resource allocation device provided in an embodiment of the present application includes a determination module 61, which determines the priority of each user terminal and the service information corresponding to each service request based on at least one service request sent by at least one user terminal; and a resource allocation module 62, which allocates return link resources to each service request based on the service information and the priority.

[0142] Further, in a possible implementation, the resource allocation module 62 includes: a highest priority user resource allocation submodule 63, a bandwidth adjustment submodule 64, a service degradation submodule 65, a user scheduling and subcarrier allocation submodule 66, and a time slot allocation submodule 67; wherein,

[0143] The highest priority user resource allocation submodule 63 is used to allocate resources to the service request corresponding to the first priority user terminal with the highest priority;

[0144] The bandwidth adjustment submodule 64 is used to adjust the service request of a user terminal to the subcarrier group with narrower bandwidth for resource allocation when the number of remaining idle time slots of a subcarrier in the subcarrier group with narrower bandwidth is not less than the number of time slots required for the service request of a user terminal;

[0145] The service degradation submodule 65 is used to downgrade at least one service that is allowed to be transmitted when the total number of time slots required for the service requests of the second priority and third priority user terminals is greater than the total number of remaining idle time slots of the corresponding subcarrier groups;

[0146] The user scheduling and subcarrier allocation submodule 66 is used to determine the relationship between the subcarrier and the service request corresponding to the user terminal;

[0147] The time slot allocation submodule 67 is used to allocate resources to the service requests corresponding to the user terminals.

[0148] To facilitate understanding, the functions of each module in the resource allocation module 62 are briefly introduced below.

[0149] 1. Highest priority user resource allocation submodule 63

[0150] This submodule performs the following operations on the first priority user in turn: according to the current number of remaining time slots of each subcarrier, a subcarrier that can meet the time slot requirements of the user is selected according to a certain principle, and for each service of the user, the time slot requirements of the service are evenly carried in the available time slots of each subframe.

[0151] 2. Bandwidth adjustment submodule 64

[0152] Specifically, the number of remaining time slots V(n) in each subcarrier in the current subcarrier group is counted to determine whether the remaining number of time slots can meet the time slot requirements of users with user priority levels 2 and 3 ∑ u t u If ∑ u t u > V(n), and the current subcarrier group is not the first subcarrier group, then the bandwidth adjustment step is performed, which is completed by submodule 2. This submodule sorts the users according to priority and determines for each user whether a narrower subcarrier can be allocated to it according to the following principles:

[0153] a) The current subcarrier group is not the first (i.e., the narrowest) subcarrier group;

[0154] b) In the channel group with narrower bandwidth, there is at least one subcarrier with idle time slot;

[0155] c) For channels with idle time slots, the number of idle time slots is sufficient to carry all services of a user in subcarrier group i.

[0156] If the service can be carried by a narrower subcarrier, the user is removed from the user group corresponding to the current subcarrier group. The above operation is performed for each service in turn until the time slot requirements of the remaining non-background services can be accommodated by the used time slots of the current channel group, that is, where t u is the total time slot requirement of user u, or the user who is not capable of bandwidth degradation.

[0157] After the above process is completed, if ∑ u t u >V(n), or the current subcarrier group is the first, the bandwidth degradation submodule 63 is activated, otherwise the user scheduling and subcarrier allocation submodule 64 is directly activated.

[0158] 3. Bandwidth degradation submodule 65

[0159] Read the set of users that still need to be carried in the current subcarrier group, calculate their time slot requirements, and determine whether the number of time slots in the current subcarrier group is sufficient. u t u > V(n), bandwidth downgrade is performed, which is completed by bandwidth downgrade submodule 63. Assume that for each type of service, users request audio and video resources of different quality or bit rate according to their terminal capabilities and personal preferences. Different quality audio and video resources correspond to different average transmission rate requirements. In order not to excessively reduce the user experience, it is stipulated that the network can downgrade the service request of each user by at most two levels. Let l uIndicates the number of times user u has been downgraded. That is, when a user request has been transmitted using the lowest rate, or the user has been downgraded twice, the service will no longer be downgraded for the user. Record the downgraded users and services, and update the average transmission rate and time slot requirements for the service.

[0160] 4. User scheduling and subcarrier allocation submodule 66

[0161] First, read the set of users that still need to be carried in the current subcarrier group, and the average rate and number of time slots required for each service of the users in the set. With the goal of maximizing the weighted rate sum of the carried services, optimize which users are carried on each subcarrier and which services the users carry.

[0162] In order to make the best decision, the user scheduling and subcarrier allocation submodule involved in the present invention can adopt a decision-making solution based on dynamic programming and bound-and-bound group multi-knapsack solution algorithm. To complete the response decision, the user scheduling and subcarrier allocation submodule 64 submodule includes 5 functions: item group conversion, group knapsack solution, upper bound, lower bound, and multi-knapsack solution.

[0163] The item group conversion function first converts the user's multiple businesses into an item group, where each item is a combination of one or more user businesses. Each user corresponds to an item group, and the items in the item group are mutually exclusive, that is, multiple items in the same item group cannot be selected at the same time, and only one item can be put into the backpack. After conversion, a user's multiple businesses can be converted into a group containing α u An item group of items, each item is represented by a business subset C of user u α ,α=1,2,.,α u The weight of each item is Value

[0164] The grouped backpack function can use the dynamic programming algorithm to obtain the optimal solution to the grouped backpack problem with multiple mutually exclusive groups of items. It is called as a sub-function by the upper bound and lower bound function sub-modules. The multi-knapsack problem solving sub-module uses the bound-and-bound algorithm to solve the multi-knapsack problem. The upper and lower bounds of the problem can be provided by the upper and lower bound functions. Figure 7 A schematic diagram of the operation flow of a user scheduling and subcarrier allocation submodule provided in an embodiment of the present application.

[0165] 5. Time slot allocation submodule 67

[0166] It is completed by the time slot allocation submodule 67, with the result of the user scheduling and subcarrier allocation submodule 66 as input, and is divided into two steps: time slot allocation for non-background services and time slot allocation for background services. First, the time slot allocation for non-background services is performed according to the results of user scheduling and subcarrier allocation, and it is determined to which user each time slot should be allocated. An allocation scheme with rate or capacity guarantee needs to be provided according to the real-time or non-real-time characteristics of the service. When the non-background user service selected to be carried has been allocated, the remaining time slot resources can be allocated to the user requesting the background service. At this point, the time-frequency resource allocation for a group of users on their corresponding group of subcarriers is completed. Then, the above process is repeated for other groups of users and subcarriers in turn until all services of all users are allocated corresponding time-frequency resources or there are no redundant resources in the system.

[0167] From the perspective of user priority, for the highest priority users, such as heads of state and important enterprise-level users, the highest priority user resource allocation submodule 61 ensures that they can obtain resources first, and provides them with rate-guaranteed services, so that the information required to be transmitted by important users can be transmitted in time. For low priority users, such as ordinary civilian users, when resources are sufficient, they are provided with the service quality guarantee they require. When resources are insufficient, their service quality is downgraded. For example, when a user requires the transmission of 1080p video, when resources are actually allocated to them, only resources for transmitting 720p video are provided. By downgrading the service quality of low priority users, the system can accommodate more users and services.

[0168] From the perspective of service type, real-time, non-real-time and background services are distinguished, and rate, capacity or best effort service is provided for different types of services through the time slot allocation submodule 67. Taking into account user priority and service type, six types of service quality guarantees can be provided.

[0169] Finally, in the user scheduling and subcarrier allocation submodule 66, since the value determination of each service request not only considers the priority of the user and the service, but also considers the transmission rate of the service, a balance between user priority and system communication performance is taken into account.

[0170] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage and optical storage, etc.) that contain computer-usable program code.

[0171] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0172] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0173] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0174] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A satellite return link resource allocation method, characterized in that: include: Determining the priority of each user terminal and service information corresponding to each service request according to at least one service request sent by at least one user terminal; Allocating return link resources to each service request according to the service information and the priority; The service information includes service type and transmission rate, wherein the service type includes real-time service, non-real-time service and best-effort service; The priorities are, in descending order, the first priority, the second priority and the third priority; Allocating return link resources to each service request according to the service information and the priority includes: Determine, according to the priority and the service type, an allocation order of return link resources for each user terminal and / or at least one service request corresponding to each user terminal; Allocating return link resources to each service request according to the allocation order; The allocation order is: the service corresponding to the user terminal with the first priority, the service type with the second priority and the real-time service, the service type with the third priority and the real-time service, the service type with the second priority and the non-real-time service, the service type with the third priority and the non-real-time service, the service type with the second priority or the third priority and the best-effort service; Allocating return link resources to each service request according to the allocation order, including: determining a maximum processing bandwidth corresponding to each user terminal, determining a user terminal group corresponding to each user terminal according to the maximum processing bandwidth, and determining a subcarrier group corresponding to each user terminal group according to a preset mapping relationship between the user terminal group and a subcarrier group in the return link resource, wherein each subcarrier group includes at least one subcarrier with the same bandwidth; Allocating return link resources for each service request of each user terminal in the subcarrier group corresponding to the user terminal in turn according to the allocation order; Allocating a return link resource to each service request of each user terminal in the subcarrier group corresponding to the user terminal in turn according to the allocation order, including: According to the size of the bandwidth of each subcarrier in the subcarrier group, the subcarrier groups corresponding to the user terminal group are sorted in order from small to large to obtain a subcarrier group sequence; According to the subcarrier group sequence and the allocation order, return link resources are allocated to at least one service request corresponding to each user terminal on the subcarrier group corresponding to each group of user terminals in turn.

2. The method according to any one of claims 1, characterized in that Allocating return link resources for at least one service request corresponding to each user terminal on the subcarrier group corresponding to each group of user terminals in turn according to the subcarrier group sequence and the allocation order, comprising: Determine the number of time slots required for service transmission corresponding to at least one service request of each user terminal in each group of user terminals, and determine the total number of first time slots required for user terminals of the first priority, the total number of second time slots required for user terminals of the second priority, and the total number of third time slots required for user terminals of the third priority according to the number of time slots; Starting from the first subcarrier group of the subcarrier group sequence, allocating time slots according to the first total number of time slots for at least one service request corresponding to the user terminal of the first priority, and determining whether the sum of the second total number of time slots and the third total number of time slots is greater than the total number of time slots remaining in the first subcarrier group; If it is greater than, then allocating return link resources to at least one service request corresponding to the user terminal of the second priority and / or the third priority in sequence according to the allocation order; until resource allocation of all subcarrier groups in the subcarrier group sequence is completed; Allocating a return link resource to at least one service request corresponding to the user terminal of the second priority and / or the third priority in sequence according to the allocation order includes: Determine whether there is a second subcarrier group and the number of idle time slots of the second subcarrier is not less than the number of time slots required by the user terminal to be currently allocated, wherein the bandwidth of the carrier in the second subcarrier group is less than the bandwidth of the subcarrier in the first subcarrier group; If so, allocating return link resources on the second subcarrier for at least one service request corresponding to the user terminal currently to be allocated; If the second subcarrier does not exist, determining whether at least one service among the services corresponding to the at least one service request can be downgraded for transmission; If there is at least one service that can be downgraded for transmission, downgrade the at least one service until the number of downgrades of the at least one service reaches a preset number or the time slot required for service transmission corresponding to the at least one service request after the downgrade is less than the remaining time slots in the subcarrier group; It also includes: if there is no at least one service that can be downgraded for transmission, the total number of the first time slots is less than the total number of remaining time slots, or after at least one service is downgraded, it also includes: determining the service request allocated to each subcarrier according to the modified branch and bound method.

3. The method according to claim 2, characterized in that The service request allocated to each subcarrier is determined according to a modified branch and bound method, including: Determine a weight value and a transmission volume of a service corresponding to each service request, and calculate the value of each service according to the weight value and the transmission volume; Determine an upper bound and a lower bound according to the value of each service and the number of remaining time slots of the subcarrier group corresponding to each group of user terminals, wherein the upper bound and the lower bound refer to the service request of the user terminal corresponding to each subcarrier and the information of the user terminal; The service request of the user terminal and the user terminal allocated to each subcarrier are determined according to the preset constraint condition, the upper bound and the lower bound.

4. A satellite return link resource allocation device, used in the method according to any one of claims 1 to 3, characterized in that: include: A determination module, determining the priority of each user terminal and the service information corresponding to each service request according to at least one service request sent by at least one user terminal received; The resource allocation module allocates return link resources to each service request according to the service information and the priority.

5. The device according to claim 4, characterized in that The resource allocation module includes: a highest priority user resource allocation submodule, a bandwidth adjustment submodule, a service degradation submodule, a user scheduling and subcarrier allocation submodule, and a time slot allocation submodule; wherein, The highest priority user resource allocation submodule is used to allocate resources to the service request corresponding to the first priority user terminal with the highest priority; The bandwidth adjustment submodule is used to adjust the service request of a user terminal to the subcarrier group with narrower bandwidth for resource allocation when the number of remaining idle time slots of a subcarrier in the subcarrier group with narrower bandwidth is not less than the number of time slots required for the service request of a user terminal; The service degradation submodule is used to downgrade at least one service that is allowed to be transmitted at a downgraded level when the total number of time slots required for service requests of the second priority and third priority user terminals is greater than the total number of remaining idle time slots of the corresponding subcarrier groups; The user scheduling and subcarrier allocation submodule is used to determine the relationship between the subcarrier and the service request corresponding to the user terminal; The time slot allocation submodule is used to allocate resources to the service requests corresponding to the user terminals.

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