KR-20260066599-A - OPTIMIZATION OF POWER ALLOCATION AND COMPRESSION RATE FOR UPLINK USER PACKET IN LEO BASED OPEN-NTN NETWORK

KR20260066599AKR 20260066599 AKR20260066599 AKR 20260066599AKR-20260066599-A

Abstract

A technology for optimizing the data and pilot transmission power allocation and compression ratio of uplink packets in a low-orbit satellite-based open non-ground network structure is disclosed. A method for optimizing the data and pilot transmission power allocation and compression ratio of uplink packets, performed by a communication system according to one embodiment, may include the steps of: configuring a system model based on a low-orbit satellite (LEO)-based open non-ground network structure; and determining the transmission power of uplink packets and the compression ratio of the inter-satellite link to maximize the user's uplink speed within the bandwidth resources used for the inter-satellite link in the configured system model.

Inventors

유희정
이준석

Assignees

고려대학교 세종산학협력단

Dates

Publication Date: 20260512
Application Date: 20250203
Priority Date: 20241104

Claims (15)

In a method for optimizing the data and pilot transmission power allocation and compression ratio of uplink packets performed by a communication system, A step of configuring a system model based on an open non-ground network architecture based on a low Earth orbit (LEO) satellite; and A step of determining the transmission power of uplink packets and the compression rate of the inter-satellite link to maximize the user's uplink speed within the bandwidth resources used for the inter-satellite link in the system model configured above. A method for optimizing data and pilot transmission power allocation and compression ratio of uplink packets including
In paragraph 1, The step of configuring the above system model is, Includes low-orbit satellites with a direct link to a ground gateway or low-orbit satellites without a direct link, A low-orbit satellite with a direct link to the above-mentioned ground gateway includes a Distributed Unit (DU) and a Radio Unit (RU) functional block, and The above-mentioned low-orbit satellite without a direct link includes an RU functional block, and Uplink packets are transmitted to low-orbit satellites containing DU function blocks using an Inter-Satellite Link (ISL) acting as a fronthaul. A method for optimizing data and pilot transmission power allocation and compression ratio of uplink packets, characterized by the following:
In paragraph 1, The above-mentioned determining step is, A step of receiving uplink packets transmitted from each user at the Mth low-orbit satellite and transmitting the received uplink packets via an inter-satellite link to the M+1th low-orbit satellite having a DU function block to connect to a ground gateway. A method for optimizing data and pilot transmission power allocation and compression ratio of uplink packets including
In paragraph 3, The above-mentioned determining step is, A step of determining whether to proceed with compression based on the bandwidth allocated to the above-mentioned inter-satellite link A method for optimizing data and pilot transmission power allocation and compression ratio of uplink packets including
In paragraph 4, The above-mentioned determining step is, A step of transmitting the received uplink packet if, through the above determination, the bandwidth allocated to the inter-satellite link is greater than or equal to a preset standard, and performing compression on the uplink packet if the bandwidth allocated to the inter-satellite link is less than a preset standard. A method for optimizing data and pilot transmission power allocation and compression ratio of uplink packets including
In paragraph 5, The above-mentioned determining step is, When an uplink packet transmitted from each user arrives at the M+1th low-orbit satellite, a channel value is obtained by performing channel estimation for each user using the pilot symbol within the uplink packet, and the obtained channel value is decoded and transmitted to a ground gateway. A method for optimizing data and pilot transmission power allocation and compression ratio of uplink packets including
In paragraph 6, The above-mentioned determining step is, A step of estimating each user's channel based on pilot symbols within each user's uplink packet using MMSE (Minimum Mean Square Error). A method for optimizing data and pilot transmission power allocation and compression ratio of uplink packets including
In paragraph 6, The above-mentioned determining step is, A step of acquiring the data symbols of each user that arrived at the M+1th low-orbit satellite based on the channel estimation of each user performed above. A method for optimizing data and pilot transmission power allocation and compression ratio of uplink packets including
In paragraph 8, The above-mentioned determining step is, A step of defining the user's achievable uplink speed based on the data symbols of each user obtained above. A method for optimizing data and pilot transmission power allocation and compression ratio of uplink packets including
In Paragraph 9, The above-mentioned determining step is, A step of adopting rate-distortion theory to verify the relationship between the bandwidth and compression rate of the inter-satellite link, and constructing an optimization problem to maximize the uplink transmission rate under inter-satellite link bandwidth constraints by utilizing Jensen's inequality for the transmission rates of compressed user pilot symbols and data symbols from low-orbit satellites. A method for optimizing data and pilot transmission power allocation and compression ratio of uplink packets including
In Paragraph 10, The above optimization problem is, It consists of a first subproblem of exploring the compression ratio of an inter-satellite link in the transmission power allocation of fixed pilot symbols and data symbols, and a second subproblem of exploring the transmission power of pilot symbols and data symbols in the compression ratio of a fixed inter-satellite link. A method for optimizing data and pilot transmission power allocation and compression ratio of uplink packets, characterized by the following:
In Paragraph 10, The above-mentioned determining step is, A step of deriving each optimal solution through each mathematical formula using the first sub-problem and the second sub-problem configured in the above optimization problem. A method for optimizing data and pilot transmission power allocation and compression ratio of uplink packets including
In Paragraph 12, The above-mentioned determining step is, A step of calculating the transmission power of the user's pilot symbols and data symbols at the compression rate of a fixed inter-satellite link through a power allocation optimization algorithm. Includes, A method for optimizing data and pilot transmission power allocation and compression ratio of uplink packets, characterized in that the above power allocation optimization algorithm sets the distortion rates of fixed pilot symbols and data symbols, and then performs an operation to determine whether specific conditions are satisfied for the transmission power calculated through a mathematical formula, thereby deriving the calculated transmission power as an optimal solution.
In Paragraph 12, The above-mentioned determining step is, A step of alternately performing the operation of searching for the transmission power of pilot symbols and data symbols that maximize the user's uplink speed through a cross-optimization algorithm, and the operation of searching for the compression rate of the inter-satellite link. A method for optimizing data and pilot transmission power allocation and compression ratio of uplink packets including
In communication systems, A system model component that constitutes a system model based on an open non-ground network structure based on a low Earth orbit (LEO) satellite; and A decision unit that determines the transmission power of uplink packets and the compression rate of the inter-satellite link to maximize the user's uplink speed within the bandwidth resources used for the inter-satellite link in the system model configured above. A communication system including

Description

Optimization of Data and Pilot Transmit Power Allocation and Compression Rate for Uplink USER Packets in a Low Earth Orbit Satellite-Based Open-Non Network Architecture The following description concerns wireless communication technology utilizing low-orbit satellites. Network structures utilizing non-terrestrial networks are increasingly being adopted to configure three-dimensional communication environments or to build communication networks robust against natural disasters or physical attacks. Among the various platforms of non-terrestrial networks, low-orbit satellites are located at low altitudes, requiring anywhere from hundreds to thousands of them to provide communication services across the entire globe. Furthermore, because they orbit the Earth at high speeds to overcome gravity, each low-orbit satellite is utilized only when passing over a specific service area; consequently, it is difficult for a single operator to configure the entire system. FIG. 1 is a diagram illustrating an open non-ground network structure in one embodiment. FIG. 2 is a diagram illustrating the functional separation of RU/DU/CU in an open non-terrestrial network in one embodiment. FIG. 3 is a diagram illustrating the process of transmitting data from a ground user to a ground gateway via several low-orbit satellites in one embodiment. FIG. 4 is a diagram illustrating an uplink packet in one embodiment. FIG. 5 is a block diagram for explaining a communication system in one embodiment. FIG. 6 is a flowchart illustrating a method for optimizing the data and pilot transmission power allocation and compression ratio of an uplink packet in one embodiment. FIG. 7 is a diagram illustrating a power allocation optimization algorithm in one embodiment. FIG. 8 is a diagram illustrating a cross-optimization algorithm in one embodiment. Hereinafter, embodiments will be described in detail with reference to the attached drawings. FIG. 1 is a diagram illustrating an open non-ground network structure in one embodiment. A communication system can configure a system model based on an open non-ground network architecture based on low Earth orbit (LEO) satellites. In this case, the communication system can provide an open non-ground network architecture where multiple service operators can share low Earth orbit satellites for cost-effective network deployment utilizing low Earth orbit satellites based on an open wireless access network architecture. As shown in Fig. 1, the communication system can define an Open Non-Ground Network (Open NTN) by integrating an open base station with a low Earth orbit satellite-based regenerative payload. In this case, the functions of the next-generation node B (gNB) in an open non-terrestrial network may include Centralized Unit (CU), Distributed Unit (DU), and radio unit (RU) function blocks. In the embodiment, the CU may be located at the terrestrial gateway. Low-orbit satellites that have a direct link with the terrestrial gateway include Distributed Unit (DU) and radio unit (RU) function blocks, while low-orbit satellites that do not have a direct link have only the RU function block. To transmit data to the core network, data must be transmitted to low-orbit satellites containing the DU function block using an Inter-Satellite Link (ISL). Here, the Inter-Satellite Link and the Feeder Link replace the roles of Fronthaul and Midhaul in existing terrestrial base stations. FIG. 2 is a diagram illustrating the functional separation of RU/DU/CU in an open non-terrestrial network in one embodiment. Referring to Figure 2, the functional separation boundary in an open non-terrestrial network is shown by incorporating the functional blocks and functional separation of the RU, DU, and CU proposed in existing open base stations. By adopting functional separation, the data subcarrier and the pilot subcarrier can be separated after Frequency Division Multiplexing (OFDM) demodulation at the RU. Therefore, in signal compression for inter-satellite link fronthall transmission, separate compression rates for the data and pilot signals can be considered. FIG. 3 is a diagram illustrating the process of transmitting data from a ground user to a ground gateway via several low-orbit satellites in one embodiment. Figure 3 shows a system model based on an open non-ground network structure based on a low-orbit satellite (LEO). The I-th user (UE) can transmit uplink packets to the low-orbit satellite located above each ground user (closest to itself). At this time, referring to Figure 4, the uplink packet consists of a total of Nt symbols and can be composed of pilot symbols (N p ) and data symbols (N d ). A low-orbit satellite can receive uplink packets transmitted from each user. A low-orbit satellite that receives uplink packets from each user possesses only an RU function block and can perform part of the reception process according to the RU block function of FIG. 2. When an uplink packet from each user arrives at the low-orbit