Space-time ripple effect suppression method of sky-ground integrated network

Abstract

The invention discloses a space-time ripple effect suppression method for a sky-ground integrated network, and the method comprises the following steps: S1, giving the sky-ground integrated network comprising a communication satellite, M unmanned planes and N ground base stations; S2, enabling access points of all layers to use a shared frequency spectrum for communication, employing a unified frame structure, dividing the frequency spectrum, and carrying out the division of the frequency spectrum; constraint conditions required to be met by channel allocation are given; and S3, space-time ripple effect modeling is carried out by combining space and time interferences, and representation and suppression conditions of the space-time ripple effect are obtained. According to the method, space-time interference existing in the sky-ground integrated network is analyzed, modeling is carried out on the space-time interference, the space-time interference is defined as a ripple effect, and interference relations and suppression conditions among different access points are described.

Description

Technical Field

[0001] The present invention relates to the field of communications, and in particular to a method for suppressing space-time ripple effects in a sky-ground integrated network. Background Art

[0002] The rapid development of communication technology has brought many challenges to traditional networks in terms of low latency, high reliability and ultra-large-scale connection requirements. In this context, based on the concept of space-air-ground uniformly integrated network, the concept of space-air-ground uniformly integrated network (SAGUIN) was proposed. This network provides users with wide coverage, high dynamic and high throughput communication services by integrating satellite networks, air networks and ground networks. However, in this architecture, due to the overlap of coverage areas between multiple layers of access points (APs), there are differences in propagation delays between access points in different layers, which causes complex spatiotemporal interference during communication. How to model and quantify the spatiotemporal interference between different access points in the network is still an unresolved research problem, and the relevant research field is still blank. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for suppressing the spatiotemporal ripple effect of a sky-ground integrated network. The spatiotemporal interference existing in the sky-ground integrated network is analyzed, modeled and defined as a ripple effect, and the interference relationship and suppression conditions between different access points are characterized.

[0004] The object of the present invention is achieved through the following technical solution: A method for suppressing the space-time ripple effect of a sky-ground integrated network, comprising the following steps: S1. Given a communication satellite, M A drone, N An integrated sky-ground network with 10 ground base stations: The communication satellites constitute a satellite network, namely the satellite layer, for providing coverage for wide-area users; the M drones constitute an aerial network, namely the aerial layer, for dynamically covering designated hotspot areas; the N ground base stations constitute a ground network, namely the ground layer, for providing high data rate access for users; access points are provided in the satellite layer, the aerial layer and the ground layer; the access points communicate with each other through intra-layer links and cross-layer links; S2. Each layer of access points uses shared spectrum for communication and adopts a unified frame structure to divide the spectrum and give constraints that need to be met for channel allocation: any resource block will not be allocated to multiple users at the same time; S3. Combine spatial and temporal interference to model the spatiotemporal ripple effect and obtain the characterization and inhibition conditions of the spatiotemporal ripple effect.

[0005] The beneficial effects of the present invention are: the present invention analyzes the spatiotemporal interference existing in the integrated sky-ground network, models and defines it as a ripple effect, describes the interference relationship between different access points, provides conditions for coordinating and preventing mutual interference between access points, and provides a new theoretical basis and technical method for this research field. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 is a flow chart of the method of the present invention; Figure 2 This is a schematic diagram of the sky-ground integrated network; Figure 3 Schematic diagram of the frame structure of the sky-ground integrated network; Figure 4 Modeling scene graphs for spatiotemporal ripple effects. DETAILED DESCRIPTION

[0007] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following.

[0008] like Figure 1 As shown, a method for suppressing the space-time ripple effect of a sky-ground integrated network includes the following steps: S1. Given a sky-ground integrated network architecture including satellite network, air network and ground network: like Figure 2 As shown in the figure, the Space-Air-Ground Uniformly Integrated Network (SAGUIN) is composed of a satellite network, an aerial network, and a ground network: the satellite network includes one or more communication satellites to provide coverage for wide-area users; the aerial network includes unmanned aerial vehicles (UAVs) and high-altitude platforms (HAPs) to dynamically cover specific hotspots; the base stations of the ground network provide users with high data rate access. Access points can communicate with each other through intra-layer links and cross-layer links. In this architecture, users connect to the network through access points to obtain services, and data is transmitted through the corresponding network to the Data and Control Center (DCC) for processing, thereby achieving unified coordination and management of resources.

[0009] To simplify the scene structure, such as Figure 4 As shown, consider a communication satellite. M A drone, N An integrated sky-ground network with 10 ground base stations: The communication satellites constitute a satellite network, namely the satellite layer, for providing coverage for wide-area users; the M drones constitute an aerial network, namely the aerial layer, for dynamically covering designated hotspot areas; the N ground base stations constitute a ground network, namely the ground layer, for providing high data rate access for users; access points are provided in the satellite layer, the aerial layer and the ground layer; the access points communicate with each other through intra-layer links and cross-layer links; S2. Each layer of access points uses a shared spectrum for communication and adopts a unified frame structure to divide the spectrum and give constraints that need to be met for channel allocation; like Figure 3 As shown in Figure 1, access points (APs) at each layer use shared spectrum for communication and adopt a unified frame structure. In each frame, frequency division multiple access technology is used to divide the spectrum into P Resource Block (RB). Access Point k At the moment t The action set is defined as ,in: U Indicates the total number of users. P Indicates the total number of channels; Indicates latitude U*P 0-1 matrix of; express The u,p ) elements. Specifically, Indicates at time t , access point k Resource Block p Assigned to user u ;and This means that the channel is not assigned. t , any one resource block will not be allocated to multiple users at the same time, and the allocation of each channel must meet the following constraints: in, K Indicates the total number of access points. P Indicates the total number of available channels. U Indicates the total number of users.

[0010] S3. Combine spatial and temporal interference to model the space-time ripple effect and obtain a representation of the space-time ripple effect.

[0011] The ripple effect is a complex spatiotemporal interference phenomenon caused by overlapping coverage and propagation delays of multiple access points. To accurately describe the ripple effect, consider Figure 4 The scene contains a communication satellite. M A drone, NFor the sake of indexing clarity, the communication satellite index is defined as k = 0, the drone index is: , the base station index is: The following modeling method is proposed: In order to characterize the spatial and temporal interference in the network, the following definitions are made: make Indicates access point k The ground level communication radius of the access point k and users u The coordinates of are expressed as and If the distance between them is less than or equal to , then the user u Considered to be at the access point k Within the coverage area, and set ,in, is a coverage indicator parameter; otherwise, the user is not within the coverage area and . Access Point k and users u The coverage relationship between is expressed as: Access Point k and users u The propagation delay between It is determined by the physical distance between the two and the type of access point. It can be calculated as: in, represents the bi-norm of the variable, c Represents the speed of light. When the access point is a ground base station, the propagation delay is 0.

[0012] Spatial interference is defined as: when the users covered by different access points overlap with the spatial area, the downlink transmission process will cause relevant interference between the access points and users at the corresponding spatial positions. The spatial interference formula is expressed as: in, is with k Compared to the lower-level access nodes; Indicates access point exist Actions in time slots; Indicates access point With users u The propagation delay of U , P , K Represent the total number of users, total number of channels and total number of access points respectively.

[0013] Time interference is defined as: the propagation delays of each access point are inconsistent. Data packets transmitted by different access points at different times may arrive at the user end at the same time after different propagation delays, thus causing interference. The time interference formula is expressed as: in, Indicates access node k exist Transmission action of time slot; summation term Indicates all covered users u The formula shows that in any time slot, the user receives service data from at most one access point.

[0014] Based on the above analysis, the interference of the sky-ground integrated network originates from the transmitter, propagates through each layer, and gradually dissipates over time, similar to the ripple effect caused by an object dropping into the water surface. Combining the interference of space and time, it is defined as the space-time ripple effect, and the final expression of the space-time ripple effect is given: The suppression conditions of space-time ripple effect are given as follows: Item 1 , check the access point k Whether to choose Select service; item 2 Evaluate the number of access points from all other access points in the resource block p This equation ensures proper coordination and prevents mutual interference between access points, depending on the transmission situation on the access point.

[0015] Since there are multiple access points in the network, it is necessary to determine whether there is mutual interference between the access points. In formula (7), the first term Indicates whether access point k is in Use channel p to transmit data to user u at time: 0 means no, 1 means yes; the second item Indicates that all access points except access point k cover user u (i.e. ) is the access point k' in the corresponding Channel p is used at all times to serve user u (here it refers to the same user u): 0 means no, non-zero means yes. The services in these two items undergo their own propagation delay ( ) will reach user u at time t. Since it is necessary to count the situations of all access points except access point k, this is the reason for the sum of the second term (since the second term is a summation term, the value of the second term may be 1, 2, 3...). When neither of these two items occurs or only one of them occurs (when the second item occurs, its value must be 1, otherwise mutual interference will occur), no interference will occur on the user side (neither of them occurs, indicating that the user side has not received the service, and only one of them occurs, indicating that the user service is successful), and the value of the expression is 0 or 1. If the two items occur at the same time, then at time t, the user will receive services from multiple APs on channel p at the same time, which will cause co-channel interference (the value of the expression is greater than 1 at this time), and the service cannot be successfully provided at this time. Therefore, the condition here must use an inequality and require the value of the overall expression to be less than or equal to 1 to limit the user to only receive services from one access point at time t, thereby avoiding mutual interference.

[0016] The above is a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not deviate from the spirit and scope of the present invention, and should be within the scope of protection of the claims attached to the present invention.

Claims

1. A method for suppressing space-time ripple effects in a sky-ground integrated network, characterized in that: The following steps are involved: S1. Given a communication satellite, M A drone, N An integrated sky-ground network with 10 ground base stations: The communication satellites constitute a satellite network, i.e., a satellite layer, for providing coverage for wide-area users; the M drones constitute an aerial network, i.e., an aerial layer, for dynamically covering designated hotspot areas; the N ground base stations constitute a ground network, i.e., a ground layer, for providing high data rate access to users; the communication satellites, drones or ground base stations serve as access points; the access points communicate with each other via intra-layer links and cross-layer links; S2. Each layer of access points uses shared spectrum for communication and adopts a unified frame structure to divide the spectrum and give constraints that need to be met for channel allocation: any resource block will not be allocated to multiple users at the same time; S3. Combine spatial and temporal interference to model the spatiotemporal ripple effect and obtain the characterization and inhibition conditions of the spatiotemporal ripple effect.

2. The method for suppressing the space-time ripple effect of a sky-ground integrated network according to claim 1, characterized in that: In step S2, the frequency division multiple access technology is used in each frame to divide the spectrum into P resource blocks, each resource block is a channel, access point k At the moment t The action set is defined as ,in: U Indicates the total number of users. The dimension is U*P 0-1 matrix of; express The u,p ) elements; Indicates at time t , access point k Resource Block p Assigned to user u ;and It means that the channel has not been allocated; In order to ensure that at any time t , any one resource block will not be allocated to multiple users at the same time, and the allocation of each channel must meet the following constraints: in, K = Indicates the total number of access points. P Indicates the total number of available channels. U Indicates the total number of users.

3. The method for suppressing the space-time ripple effect of a sky-ground integrated network according to claim 1, characterized in that: The step S3 comprises: S301. Define the spatiotemporal ripple effect as a complex spatiotemporal interference phenomenon caused by overlapping coverage and propagation delays of multiple layers of access points, and give the indexes of satellites, drones, and ground base stations; S302. Define time interference and space interference; S303. Model the space-time ripple effect by combining spatial and temporal interference to obtain the characterization and inhibition conditions of the space-time ripple effect.

4. The method for suppressing the spatiotemporal ripple effect of a sky-ground integrated network according to claim 3, characterized in that: The step of communication satellite index is defined as k = 0, the drone index is: , the ground base station index is: .

5. The method for suppressing the space-time ripple effect of a sky-ground integrated network according to claim 3, characterized in that: The step S302 includes: In order to characterize the spatial and temporal interference in the network, the following definitions are made: make Indicates access point k The ground level communication radius of the access point k and users u The coordinates of are expressed as and ; If the distance between them is less than or equal to , then the user u Considered to be at the access point k Within the coverage area, and set ,in, is a coverage indicator parameter; otherwise, the user is not within the coverage area and ; Access Point k and users u The coverage relationship between is expressed as: Access Point k and users u The propagation delay between It is determined by the physical distance between the two and the type of access point, and can be calculated as: in, represents the bi-norm of the variable, c Represents the speed of light. When the access point is a ground base station, the propagation delay is 0. Definition of spatial interference: When the users covered by different access points overlap with the spatial area, the downlink transmission process will cause relevant interference between the access points and users at the corresponding spatial positions. The spatial interference formula is expressed as: in, is with k Compared to the lower-level access nodes; Indicates access point exist Actions in time slots; Indicates access point With users u The propagation delay of U , P , K Respectively represent the total number of users, the total number of channels and the total number of access points; Definition of time interference: The propagation delays of each access point are inconsistent. Data packets transmitted by different access points at different times may arrive at the user end at the same time after different propagation delays, thus causing interference. The time interference formula is expressed as: in, Indicates access node k exist Transmission action of time slot; summation term Indicates all covered users u The total transmission result of the access points is shown in the formula. In any time slot, the user receives service data from at most one access point.

6. The method for suppressing the space-time ripple effect of a sky-ground integrated network according to claim 3, characterized in that: The step S303 includes: The interference of the sky-ground integrated network originates from the transmitter, propagates through each layer, and gradually dissipates over time, similar to the ripple effect caused by an object dropping into the water surface. Combining the interference of space and time, it is defined as the space-time ripple effect, and the final expression of the space-time ripple effect is given: The suppression conditions of space-time ripple effect are given as follows: Item 1 , check the access point k Whether to choose Select service; item 2 Evaluate the number of access points from all other access points in the resource block p This equation ensures proper coordination and prevents mutual interference between access points, depending on the transmission situation on the access point.

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