User equipment communicating with base station and operation method of user equipment

Abstract

A user equipment (UE) communicating with a base station (BS) and an operation method of the UE are provided. The operation method of a UE communicating with a base station (BS) includes calculating a frequency offset difference between a serving cell and an interfering cell based on a first frequency offset of the serving cell and a second frequency offset of the interfering cell, the frequency offset difference including a subcarrier offset and a residual frequency offset, the subcarrier offset being an integer multiple of a subcarrier spacing (SCS); and removing an interference signal from a received signal received by the UE by compensating the frequency offset difference based on the residual frequency offset.

Description

[0001] This application is based on and claims priority to Korean Patent Application No. 10-2024-0062195, filed on May 10, 2024, with the Korean Intellectual Property Office, and Korean Patent Application No. 10-2024-0094007, filed on July 16, 2024, the entire disclosure of which is incorporated herein by reference. Technical Field

[0002] The inventive concept relates to wireless communication, and more specifically, to a user equipment (UE) and a method of operation for removing interference signals caused by neighboring cells. Background Technology

[0003] Satellite communication systems have been developed as the next generation of mobile communication systems to meet the explosive growth in demand for wireless data services due to the commercialization of existing terrestrial networks (such as Long Term Evolution (LTE) or New Radio (NR) communication systems) and the increase in multimedia services, and to overcome the coverage limitations of existing terrestrial networks.

[0004] Satellite communication systems can offer wider coverage, but they can also suffer significant interference due to overlapping coverage between cells. Specifically, because base stations (BSs) transmit cell-specific reference signals (CRS) across the entire bandwidth, CRS interference can occur between neighboring cells. UE performance and network performance are degraded due to CRS interference between neighboring cells. Summary of the Invention

[0005] The inventive concept provides a user equipment (UE) and an operating method for the UE, wherein the UE divides a frequency offset difference into a subcarrier offset and a residual frequency offset, and performs an interference signal removal operation to compensate for the frequency offset difference based on the residual frequency offset. An embodiment provides a UE and its operating method for effectively removing interference signals caused by neighboring cells.

[0006] Furthermore, the inventive concept is not limited to those described above, and those skilled in the art will clearly understand the inventive concept from the following description.

[0007] According to one aspect of the inventive concept, an operating method for a UE communicating with a base station (BS) is provided, the operating method comprising: calculating a frequency offset difference between the serving cell and the interfering cell based on a first frequency offset of the serving cell and a second frequency offset of the interfering cell, the frequency offset difference including a subcarrier offset and a residual frequency offset, the subcarrier offset being an integer multiple of the subcarrier spacing (SCS); and removing the interfering signal from a received signal received by the UE by compensating for the frequency offset difference based on the residual frequency offset.

[0008] According to one aspect of the inventive concept, a method for operating a UE communicating with a BS is provided, the method comprising: detecting a first frequency offset of a serving cell provided by the BS and a second frequency offset of an interfering cell; calculating a normalized frequency offset by normalizing the frequency offset difference with a subcarrier spacing (SCS), the frequency offset difference being the difference between the first frequency offset and the second frequency offset; calculating a residual frequency offset and a subcarrier offset based on the normalized frequency offset, the subcarrier offset being an integer multiple of the SCS; determining whether the absolute value of the residual frequency offset is greater than or equal to a threshold; and responding to determining the absolute value of the residual frequency offset... If the value is greater than or equal to a threshold, a first interference signal removal operation of repeatedly compensating for frequency offset difference is performed on the received signal received by the UE; in response to determining that the absolute value of the residual frequency offset is less than the threshold, it is determined whether there is an interfering cell-specific reference signal (CRS) conflict, which is caused by the overlap of the CRS position of the interfering cell and the CRS position of the serving cell; in response to determining that there is an interfering CRS conflict, a second interference signal removal operation of repeatedly compensating for subcarrier offset is performed on the received signal; and in response to determining that there is no interfering CRS conflict, a third interference signal removal operation of compensating for subcarrier offset only once is performed on the received signal.

[0009] According to one aspect of the inventive concept, a UE communicating with a BS is provided, the UE comprising: a processing circuitry configured to: calculate a frequency offset difference between the serving cell and the interfering cell based on a first frequency offset of the serving cell and a second frequency offset of the interfering cell, the frequency offset difference including a subcarrier offset and a residual frequency offset, the serving cell being provided by the BS, and the subcarrier offset being an integer multiple of the subcarrier spacing (SCS); and perform an interference signal removal operation to remove an interfering signal from a received signal by compensating the frequency offset difference based on the residual frequency offset, the interfering signal being caused by the interfering cell, and the received signal being received by the UE.

[0010] According to one aspect of the inventive concept, the processing circuit system is configured to: perform a second interference signal removal operation in response to determining that an interference CRS conflict exists, and perform a third interference signal removal operation in response to determining that an interference CRS conflict does not exist.

[0011] According to one aspect of the inventive concept, the threshold is based on one of the following: Reference Signal Received Power (RSRP), Received Signal Strength Indicator (RSSI), or Signal-to-Interference-plus-Noise Ratio (SINR).

[0012] According to one aspect of the inventive concept, the subcarrier offset is a maximum integer less than or equal to twice the normalized frequency offset, which is normalized in terms of SCS, and the residual frequency offset is a value obtained by subtracting the subcarrier offset from the normalized frequency offset.

[0013] According to one aspect of the inventive concept, the processing circuitry is configured to receive bandwidth information of the interfering cell from the BS via one of Radio Resource Control (RRC) signaling, Media Access Control-Control Element (MAC-CE) signaling, or Downlink Control Indicator (DCI) signaling, and to perform an interference signal removal operation corresponding to the bandwidth of the interfering cell based on the bandwidth information. Attached Figure Description

[0014] Brief descriptions of the various figures are provided to obtain a detailed description of the inventive concept and a full understanding of the figures.

[0015] The embodiments will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings.

[0016] Figure 1 This is a block diagram illustrating a wireless communication system according to an embodiment.

[0017] Figure 2 This is a diagram illustrating the basic time-frequency domain structure of a radio resource region in a wireless communication system according to an embodiment.

[0018] Figure 3 This is a flowchart of an operation method of a user equipment (UE) according to an embodiment.

[0019] Figure 4 This is a flowchart of the operation method of the UE according to an embodiment.

[0020] Figure 5 This is a flowchart of the first interference signal removal operation according to an embodiment.

[0021] Figure 6 This is a flowchart of the second interference signal removal operation according to an embodiment.

[0022] Figure 7 This is a flowchart of the third interference signal removal operation according to an embodiment.

[0023] Figure 8 This is a flowchart of an operation method of a wireless communication system according to an embodiment.

[0024] Figure 9 This is a block diagram of the UE according to an embodiment.

[0025] Figure 10 This is a block diagram of an electronic device according to an embodiment.

[0026] Figure 11 This is a conceptual diagram illustrating an Internet of Things (IoT) network system with an applied embodiment. Detailed Implementation

[0027] Although the embodiments described below are based on wireless communication systems using New Radio (NR) networks or Long Term Evolution (LTE) networks (particularly the 3rd Generation Partnership Project (3GPP)), the inventive concept is not limited to NR or LTE networks. The inventive concept can also be applied to other wireless communication systems with similar technical backgrounds or channel settings (e.g., cellular communication systems for next-generation communications (such as LTE-A Advanced, WiBro, GSM, and / or 6G)) and / or short-range communication systems (such as Bluetooth, Near Field Communication (NFC), etc.).

[0028] In the embodiments described below, hardware methods are presented as examples. However, because the embodiments include techniques using both hardware and software, the embodiments do not exclude software-based methods (e.g., methods using both software and hardware).

[0029] The various functions described below can be implemented or supported by artificial intelligence techniques or one or more computer programs, each of which can be implemented as computer-readable program code and can be executed on a non-transitory computer-readable recording medium. The terms "application" and "program" mean one or more computer programs, software components, instruction sets, procedures, functions, objects, classes, instances, associated data, or portions thereof suitable for implementing appropriate computer-readable program code. The term "computer-readable program code" includes any type of computer code, including source code, object code, and executable code. The term "computer-readable recording medium" includes any type of memory accessible by a computer (such as read-only memory (ROM), random access memory (RAM), hard disk drive, optical disc (CD), digital video disc (DVD), or any other type of memory). "Non-transitory" computer-readable recording media excludes wired, wireless, optical, or other communication links that transmit transient electrical or other signals. Non-transitory computer-readable recording media includes media that allow data to be stored permanently, as well as media that allow data to be stored and later rewritten (such as rewritable optical discs or erasable memory devices).

[0030] In the following description, embodiments will be described in detail with reference to the accompanying drawings.

[0031] Figure 1 This is a block diagram illustrating a wireless communication system 10 according to an embodiment. Figure 2 This is a diagram illustrating the basic structure of the time-frequency domain as a radio resource area in the wireless communication system 10 according to an embodiment.

[0032] Reference Figure 1 The wireless communication system 10 may include base stations (BS) 110, 120 and / or 130, and / or user equipment (UE) 140. In this specification, only BS 110, 120 and / or 130 and UE 140 are shown, but the inventive concept is not limited thereto. For example, other UEs (not shown) may also be included, and only some of BS 110, 120 and / or 130 may be included, or other BSs (not shown) may also be included.

[0033] BS 110, 120, and / or 130 may represent a fixed station communicating with UE 140 and / or another BS (not shown), or may represent a mobile satellite (e.g., a geostationary orbit (GEO) satellite or a low Earth orbit (LEO) satellite communicating with UE 140 and / or another BS (not shown). For example, BS 110 and 120 may support non-terrestrial networks, and BS 130 may support terrestrial networks.

[0034] BS 110, 120, and / or 130 can exchange data and control information with UE 140 and / or other BS (not shown) while communicating with UE 140 and / or other BS (not shown). For example, BS 110, 120, and / or 130 may be referred to as serving cell, cell, Node B, evolved Node B (eNB), next-generation Node B (gNB), sector, site, base transceiver system (BTS), access point (AP), relay node, remote radio head (RRH, also known as a remote radio head), radio unit (RU), small cell, device, etc. BS 110, 120, and / or 130 can provide wireless broadband access to UE 140 within their coverage areas 111, 121, and / or 131.

[0035] UE 140 may refer to any device, whether stationary or mobile, capable of communicating with BS 110, 120, and / or 130 to send and receive data and / or control information to and from BS 110, 120, and / or 130. For example, UE 140 may be referred to as a terminal, terminal equipment, mobile station (MS), mobile terminal (MT), user terminal (UT), subscriber station (SS), wireless communication device, wireless device, handheld device, etc.

[0036] In this embodiment, UE 140 may initially connect to and perform wireless communication with BS 110, and may be located in an area where the coverage areas 111 of BS 110, 121 of BS 120, and 131 of BS 130 overlap. Because of this overlapping coverage, interference signals may arise from cells adjacent to BS 110 (e.g., BS 120 and / or 130). For example, a cell-specific reference signal (CRS) may be allocated to an entire resource block (RB) of bandwidth. UE 140, located at the edge of the coverage area 111 of BS 110, may receive CRS as interference signals from cells adjacent to BS 110 (e.g., BS 120 and / or 130), and the CRS received from the adjacent cells may be referred to as interfering CRS. Hereinafter, the cell communicating with UE 140 is referred to as the serving cell, and the cell among the cells adjacent to the serving cell that may affect the received signal received by UE 140 is referred to as the interfering cell.

[0037] When interference signals are generated due to interfering cells, the performance of UE 140 or wireless communication system 10 may be degraded. In a comparative example, further enhanced inter-cell interference coordination (FeICIC) can be used to remove interference signals. FeICIC can represent an interference signal removal method in which BS 110 informs UE 140 of the location of the interfering CRS without sending data to it, enabling UE 140 to remove the interfering CRS.

[0038] However, FeICIC can be used when the frequency offset difference between the serving cell and the interfering cell is relatively small (e.g., approximately 0.05 ppm). BSs supporting non-terrestrial networks (e.g., BS 110 or 120) can move at relatively high speeds, and the frequency offset difference between the serving cell and the interfering cell may be relatively large due to Doppler shift.

[0039] For example, BS 110 may move at a high speed (e.g., 300 km / h), and due to Doppler shift, the frequency offset difference between the serving cell (e.g., BS 110) and the stationary interfering cell (e.g., BS 130) may be approximately 328 Hz. For example, the frequency offset difference between the serving cell and the interfering cell due to Doppler shift may be greater than half of the subcarrier spacing (SCS). SCS can represent a constant-amplitude frequency spacing between adjacent subcarriers. Therefore, it may not be possible to remove the interfering signal by using FeICIC according to the comparative example.

[0040] Refer to the explanation of SCS Figure 2The horizontal axis represents the time domain, and the vertical axis represents the frequency domain. The smallest transmission unit in the time domain is an orthogonal frequency division multiplexing (OFDM) symbol, and N symb One OFDM symbol 202 can be aggregated to configure a time slot 206. Two time slots can be aggregated to configure a subframe 205. In an embodiment, the length of time slot 206 can be 0.5 ms, and the length of subframe 205 can be 1.0 ms. However, this is only an example. The length of time slot 206 can vary depending on the configuration of time slot 206, and the number of time slots 206 included in subframe 205 can vary depending on the length of time slot 206. On the other hand, in an NR network, the time-frequency domain can be defined centered on time slot 206. Furthermore, radio frame 214 can be a time-domain unit comprising ten subframes 205.

[0041] The smallest transmission unit in the frequency domain is a subcarrier, and the total system transmission bandwidth can be configured with a total of N. BW There are 204 subcarriers. SCS can represent N. BW A constant amplitude frequency interval between subcarriers 204. The basic unit of a resource in the time-frequency domain is a resource element (RE) 212, which can be represented by OFDM symbol index and subcarrier index. A resource block (RB) 208 can be defined as N in the time domain. symb 202 consecutive OFDM symbols and N in the frequency domain RB 210 consecutive subcarriers. Therefore, an RB 208 may include N symb *N RB Each RE 212. An RB pair is a unit of two RBs cascaded in the time domain, and may include N. symb *2N RB RE 212.

[0042] Return to reference Figure 1 FeICIC can be used according to the comparison example when the bandwidth of the serving cell is equal to the bandwidth of the interfering cell. Because BSs supporting non-terrestrial networks (e.g., BS 110 or 120) can use relatively narrow bandwidth, the bandwidth of the serving cell may differ from that of the interfering cell.

[0043] For example, when the serving cell is BS 110 and the interfering cell is BS 120, the bandwidth of BS 110 may include Figure 2 N BW There are 204 subcarriers, and the bandwidth of BS 120 can include more than Figure 2 N BW With 204 fewer subcarriers, the serving cell's bandwidth may differ from the interfering cell's bandwidth. Therefore, using FeICIC according to the comparative example may not remove the interfering signal.

[0044] To address this issue, the wireless communication system 10 according to the inventive concept can divide the frequency offset difference between the serving cell (e.g., BS 110) and the interfering cell (e.g., BS 130) into subcarrier offset and residual frequency offset, and can perform interference signal removal operations based on the residual frequency offset, either compensating for the subcarrier offset or compensating for both the subcarrier offset and the residual frequency offset. The subcarrier offset has a value corresponding to an integer multiple of the SCS. Therefore, even when the frequency offset difference between the serving cell and the interfering cell is relatively large, the interference signal caused by the interfering cell can be effectively removed, and the performance of the wireless communication system 10 can be improved.

[0045] Furthermore, the UE 140 according to the inventive concept can obtain the bandwidth information of the interfering cell (e.g., BS 120) through signaling with the serving cell (e.g., BS 110), and perform interference signal removal operations corresponding to the bandwidth of the interfering cell based on the bandwidth information of the interfering cell. Therefore, even when the bandwidth of the serving cell is different from the bandwidth of the interfering cell, the interference signal caused by the interfering cell can be effectively removed. Thus, the performance of the UE 140 can be improved.

[0046] The following reference Figures 3 to 11 Describe a specific example of the interference signal removal operation based on the inventive concept.

[0047] Figure 3 This is a flowchart of a UE operation method according to an embodiment. (Refer to...) Figure 3 The operation method 30 for removing interference signals caused by interfering cells in a UE may include multiple operations S310 and S320.

[0048] Further reference Figure 1 In operation S310, UE 140 can calculate the frequency offset difference between the serving cell and the interfering cell, which includes subcarrier offset and residual frequency offset. The subcarrier offset can be expressed as an integer multiple of the SCS, and the residual frequency offset can represent the remaining frequency offset difference excluding the subcarrier offset. In an embodiment, UE 140 can perform wireless communication by initially connecting to BS 110. When assuming the frequency offset of the serving cell signal transmitted by BS 110 is 0, the received signal received by UE 140 can be expressed as the following equation.

[0049] [Equation 1] .

[0050] This can represent the received signal in the time domain received by UE 140. It can represent the serving cell signal, and It can represent interfering cell signals, which are interference signals that reflect the frequency offset difference between the serving cell and the interfering cell. It can represent the size of the Fast Fourier Transform (FFT). It can be represented as the frequency offset obtained by normalizing the frequency offset difference between the serving cell and the interfering cell to the SCS, and can be called the normalized frequency offset. Noise can be represented. According to the embodiment, "n" can represent time (e.g., symbol, time slot, etc.). Equation 1 above can be applied even when the frequency offset of the serving cell signal is not 0. For example, UE 140 can set the frequency offset of the serving cell signal to 0 by adjusting the center frequency based on the frequency offset of the serving cell.

[0051] Interference with cell signals It can be represented in the frequency domain as the following equation.

[0052] [Equation 2] .

[0053] This can represent interfering cell signals in the frequency domain received by UE 140. According to an embodiment, "k" can represent a frequency (e.g., a subcarrier, etc.).

[0054] In this embodiment, the subcarrier offset is defined as being less than or equal to the normalized frequency offset. The maximum (or highest) integer is twice the normalized frequency offset, and the residual frequency offset is defined by the normalized frequency offset. When the value obtained by subtracting the subcarrier offset is used, the interfering cell signal is considered when the frequency offset difference is divided into subcarrier offset and residual frequency offset. It can be represented by the following equation.

[0055] [Equation 3] .

[0056] This can represent subcarrier offset. It can represent the residual frequency offset and can have a value greater than or equal to -0.5 and less than 0.5. UE 140 can calculate, including subcarrier offset, based on the frequency offset of the serving cell and the frequency offset of the interfering cells. and residual frequency offset Frequency offset difference.

[0057] In operation S320, UE 140 can perform interference signal removal operations based on the residual frequency offset. The closer the absolute value of the residual frequency offset is to 0, the relatively smaller the impact of interference CRS; conversely, the closer the absolute value of the residual frequency offset is to 0.5, the relatively larger the impact of interference CRS. For example, when the absolute value of the residual frequency offset is 0, interference signal removal operations can be performed on the received signal received by UE 140 by considering the subcarrier offset; and when the absolute value of the residual frequency offset is 0.5, interference signal removal operations can be performed on the received signal received by UE 140 by considering both the subcarrier offset and the residual frequency offset.

[0058] In an embodiment, the interference signal removal operation may include: a first interference signal removal operation that repeatedly compensates for the frequency offset difference (e.g., subcarrier offset and residual frequency offset) between the serving cell and the interfering cell on the received signal received by UE 140; a second interference signal removal operation that repeatedly compensates for the subcarrier offset on the received signal received by UE 140; and / or a third interference signal removal operation that compensates for the subcarrier offset once on the received signal received by UE 140. UE 140 may perform the first to third interference signal removal operations based on the absolute value of the residual frequency offset.

[0059] For example, UE 140 may perform a first interference removal operation when (e.g., in response to determining) the absolute value of the residual frequency offset is greater than or equal to a threshold, a second interference removal operation when (e.g., in response to determining) the absolute value of the residual frequency offset is less than the threshold and an interference CRS conflict exists, and a third interference removal operation when (e.g., in response to determining) the absolute value of the residual frequency offset is less than the threshold and no interference CRS conflict exists. An interference CRS conflict may indicate that the CRS location of the interfering cell overlaps with the CRS location of the serving cell. See below for reference. Figures 4 to 7 Describe specific examples of the first to third interference signal removal operations.

[0060] The first interference removal operation consumes relatively more power than the second or third interference removal operation, but it can remove interference signals more accurately. The UE 140 according to the inventive concept can perform interference removal operations based on residual frequency offset, or on both subcarrier offset and residual frequency offset. Therefore, interference signals caused by interfering cells can be effectively removed, thus improving the performance of the UE 140.

[0061] Figure 4 This is a flowchart of a UE operation method according to an embodiment. (Refer to...) Figure 4The UE operation method 40 for removing interference signals caused by interfering cells may include multiple operations S410 to S480.

[0062] Further reference Figure 1 In operation S410, UE 140 can detect a first frequency offset of the serving cell and a second frequency offset of the interfering cell. In an embodiment, UE 140 can receive information about the serving cell and interfering cell from BS 110, with which UE 140 initially connects and performs wireless communication, and can detect the first and second frequency offsets by searching for the serving cell and interfering cell based on the information received from the signal.

[0063] In operation S420, UE 140 can calculate the normalized frequency offset by normalizing the frequency offset difference with SCS. The frequency offset difference can represent the difference between a first frequency offset and a second frequency offset. In an embodiment, UE 140 can calculate the frequency offset difference based on the first and second frequency offsets detected in operation S410, and can signal information about SCS from BS 110, with which UE 140 initially connects and performs wireless communication. UE 140 can calculate the normalized frequency offset by normalizing the frequency offset difference with SCS. The offset after normalization of the frequency can be equal to the normalized frequency offset in Equation 1 above. .

[0064] In operation S430, UE 140 can calculate the residual frequency offset and subcarrier offset based on the normalized frequency offset. In an embodiment, UE 140 can calculate a frequency offset less than or equal to the normalized frequency offset. The subcarrier offset is calculated by taking twice the largest (or highest) integer from the normalized frequency offset. The value obtained by subtracting the subcarrier offset is used as the residual frequency offset.

[0065] In operation S440, UE 140 may determine whether the absolute value of the residual frequency offset is greater than or equal to a threshold. The threshold may represent a specific preset (or optionally, given) value. In embodiments, the threshold may be a preset (or optionally, given) value from 0 to 0.5 based on any one of the Reference Received Power (RSRP), Received Signal Strength Indicator (RSSI), or Signal-to-Interference-plus-Noise Ratio (SINR). For example, when any one of RSRP, RSSI, or SINR has a relatively large value, the threshold may be set relatively closer to 0.5, and when any one of RSRP, RSSI, or SINR has a relatively small value, the threshold may be set relatively closer to 0.

[0066] In operation S450, when UE 140 determines in operation S440 that the absolute value of the residual frequency offset is greater than or equal to a threshold, UE 140 may perform a first interference signal removal operation on the received signal received by UE 140 to repeatedly compensate for the frequency offset difference between the serving cell and the interfering cell.

[0067] In operation S460, when UE 140 determines in operation S440 that the absolute value of the residual frequency offset is less than a threshold, UE 140 can determine whether an interfering CRS conflict exists. An interfering CRS conflict can indicate that the CRS location of the interfering cell overlaps with the CRS location of the serving cell. In an embodiment, when UE 140 determines that the absolute value of the residual frequency offset is less than the threshold, UE 140 may disregard the residual frequency offset. Therefore, the frequency offset difference can be equal to the subcarrier offset. When in a resource block (e.g., Figure 2 If, within RB208, there exists at least one serving cell CRS location and at least one interfering cell CRS location that satisfy the following equation, UE 140 can determine that an interfering CRS conflict exists.

[0068] [Equation 4] .

[0069] It can represent a resource block (e.g., Figure 2 The CRS location of the serving cell within RB 208, and It can represent a resource block (e.g., Figure 2 The CRS location of the interfering cell within RB 208. This can represent subcarrier offset.

[0070] In operation S470, when UE 140 determines in operation S460 that there is an interfering CRS conflict, UE 140 may perform a second interference signal removal operation on the received signal received by UE 140 to compensate for the subcarrier offset.

[0071] In operation S480, when UE 140 determines in operation S460 that there is no interfering CRS conflict, UE 140 may perform a third interference signal removal operation to compensate for the first subcarrier offset on the received signal received by UE 140.

[0072] Figure 5 This is a flowchart of the first interference signal removal operation according to an embodiment. (Refer to...) Figure 5 The first interference signal removal operation 50 may include multiple operations S510 to S560.

[0073] Further reference Figure 1In operation S510, UE 140 may perform a first operation to compensate for the frequency offset difference based on the interference signal caused by the interfering cell. In an embodiment, UE 140 may do so by adjusting the received signal in Equation 1 above. The frequency offset difference is compensated to generate the compensated interference signal as shown in the equation below.

[0074] [Equation 5] .

[0075] This can represent the compensated interference signal obtained by compensating for the frequency offset difference in the time domain, and It can represent the signal obtained by adding noise to the serving cell signal.

[0076] In operation S520, UE 140 can perform a second operation to estimate the interference CRS channel based on the compensated interference signal. In an embodiment, UE 140 can use FFT to calculate the compensated interference signal in the time domain. The frequency domain is converted, and interfering cell CRS channel estimation can be performed using the received signal at the CRS location of the interfering cell (e.g., at the time / frequency resources of the interfering cell's CRS transmission signal) and the interfering cell's CRS transmission signal. UE140 can obtain information about the interfering cell's CRS transmission signal (e.g., the RE location and RB area of ​​the interfering cell's CRS transmission signal) based on the BS 110 that performs wireless communication with UE140 or the interfering cell's Master Information Block (MIB).

[0077] For example, the compensated interference signal in the frequency domain through FFT can be expressed as Equation 6 below, and the interference CRS estimated channel can be expressed as Equation 7 below based on Equation 6 below.

[0078] [Equation 6] .

[0079] It can represent the compensated interference signal in the frequency domain.

[0080] [Equation 7] .

[0081] It can represent the CRS transmission signal of the interfering cell in the frequency domain, and CE(y,x) can represent the channel estimation operation using channels y and x. This can represent the interference CRS estimation channel using CE(y,x).

[0082] In operation S530, UE 140 may perform a third operation to remove interference signals from the received signal based on interference CRS channel estimation. In this embodiment, UE 140 may estimate the channel based on interference CRS. To recover the interference signal, the frequency offset difference in the time domain is compensated in operation S510, and then the interference signal is removed from the entire received signal.

[0083] For example, the interference signal recovered by UE 140 can be represented as Equation 8 below, and the received signal with the interference signal removed based on Equation 8 below can be represented as Equation 9 below.

[0084] [Equation 8] .

[0085] This can represent channel estimation based on interference CRS. The recovered interference signal.

[0086] [Equation 9] .

[0087] It can represent the received signal in the time domain after interference has been removed, and This can be represented by applying the inverse FFT to the recovered interference signal. The recovered interference signal in the time domain is obtained. It can represent residual interference signals and noise, and the residual interference signal can represent When the residual interference signal is 0, it indicates that the interference signal has been completely removed.

[0088] In operation S540, UE 140 may perform a fourth operation of estimating the serving CRS channel based on the received signal after interference has been removed. In an embodiment, UE 140 may use FFT to perform the received signal after interference has been removed. (This can also be referred to here as the updated received signal) is converted to the frequency domain and the serving CRS channel estimation is performed based on the serving cell's CRS transmitted signal.

[0089] For example, the received signal in the frequency domain after interference has been removed by FFT can be represented as Equation 10 below, and the serving CRS estimated channel can be represented as Equation 11 below based on Equation 10 below.

[0090] [Equation 10] .

[0091] It can represent the received signal in the frequency domain after interference has been removed.

[0092] [Equation 11] .

[0093] It can represent the CRS transmission signal of the serving cell in the frequency domain, and This can represent the service CRS estimation channel using CE(y,x).

[0094] In operation S550, UE 140 may perform a fifth operation to recover the received signal received from the serving cell based on serving CRS channel estimation. In an embodiment, UE 140 may estimate the channel based on serving CRS. To restore the received signal from the serving cell.

[0095] For example, the received signal recovered by UE 140 can be represented by the following equation 12.

[0096] [Equation 12] .

[0097] Channel can be estimated based on service CRS. The received signal from the serving cell has been restored.

[0098] In operation S560, UE 140 may sequentially repeat operations one through five. In an embodiment, UE 140 may sequentially repeat operations one through five based on the received signal received from the serving cell after recovery. For example, UE 140 may repeat the entire received signal from the first operation that was immediately preceding (or immediately preceding) the previous operation (e.g., the received signal in Equation 1). The effects of the recovered received signal from the serving cell in the fifth operation, which is performed immediately before (or immediately before), are removed, and then operations one through five are performed. According to an embodiment, operations one through five can be performed on the remaining portion of the received signal obtained by removing (e.g., subtracting) the recovered received signal from the entire received signal. The entire received signal, from which the effects of the recovered received signal from the serving cell have been removed, can be represented by the following equation.

[0099] [Equation 13] .

[0100] It can represent the entire received signal in the time domain, after removing the effects of the recovered received signal from the serving cell, and It can represent the recovered received signal from the serving cell in the time domain, and the inverse FFT is applied to the recovered received signal from the serving cell. . It can represent residual service signals and noise, and the residual service signal can be represented as When the residual service signal is 0, it indicates that the influence of the received signal from the serving cell has been completely removed.

[0101] In an embodiment, UE 140 may sequentially repeat operations one through five until a convergence condition is met. For example, a convergence condition may be that the difference between the SINR of the first iteration operation and the SINR of the second iteration operation following the first iteration operation (e.g., between successive iterations) is less than a threshold SINR. For example, a convergence condition may be that the mean square error (MSE) of the serving cell's channel (e.g., channel estimation) in the first iteration operation and the serving cell's channel (e.g., channel estimation) in the second iteration operation following the first iteration operation is less than a specific value (e.g., a preset (or optionally, a given) value).

[0102] Figure 6 This is a flowchart of the second interference signal removal operation according to an embodiment. (Refer to...) Figure 6 The second interference signal removal operation 60 may include multiple operations S610 to S660.

[0103] Further reference Figure 1 In operation S610, UE 140 may perform a first operation to compensate for subcarrier offset based on the interference signal caused by the interfering cell. In an embodiment, UE 140 may calculate the received signal in the frequency domain by applying an FFT to the received signal and generate the compensated interference signal by compensating for the subcarrier offset. When UE 140 determines that the absolute value of the residual frequency offset is less than a threshold, UE 140 may disregard the residual frequency offset. Because the frequency offset difference may be equal to (or similar to) the subcarrier offset (or considered to be equal to the subcarrier offset), the received signal may be expressed as Equation 15 below, and the compensated interference signal may be expressed as Equation 16 below.

[0104] [Equation 15] .

[0105] This can represent the received signal in the time domain when the residual frequency offset is not considered, and This can represent subcarrier offset.

[0106] [Equation 16] .

[0107] It can represent the compensated interference signal, and This can represent the received signal in the frequency domain where FFT is applied and subcarrier offset is compensated.

[0108] In operation S620, UE 140 may perform a second operation of estimating the interference CRS channel based on the compensated interference signal. In an embodiment, UE 140 may use the received signal present at the CRS location of the interfering cell and the CRS transmitted signal of the interfering cell to compensate the interference signal. Perform CRS channel estimation for the interfering cell. UE 140 can obtain information about the CRS transmission signal of the interfering cell (e.g., the RE location and RB area of ​​the interfering cell's CRS transmission signal) based on BS 110, which performs wireless communication with UE 140, or the MIB of the interfering cell. For example, UE 140 can calculate the interfering CRS estimated channel using CE(y,x) in the same manner (or similarly) as in Equation 7 above.

[0109] In operation S630, UE 140 may perform a third operation to remove interference signals from the received signal from the serving cell based on interference CRS channel estimation. In an embodiment, UE 140 may recover the interference signal based on the calculated interference CRS estimated channel, compensate for subcarrier offset based on the serving cell, and then remove the interference signal from the entire received signal in operation S630.

[0110] For example, the interference signal recovered by UE 140 can be calculated in the same way (or similarly) as in Equation 8 above, and the received signal after removing the interference signal can be expressed as the following equation: [Equation 17] .

[0111] It can represent the received signal in the frequency domain after interference has been removed.

[0112] In operation S640, UE 140 may perform a fourth operation of estimating the serving CRS channel based on the received signal after interference has been removed. In an embodiment, UE 140 may calculate the serving CRS estimated channel by using CE(y,x) in the same manner (or similarly) as in Equation 11 above.

[0113] In operation S650, UE 140 may perform a fifth operation to recover the received signal received from the serving cell based on the serving CRS channel estimation. In an embodiment, UE 140 may recover the received signal received from the serving cell based on the serving CRS estimated channel. For example, the received signal recovered by UE 140 may be calculated in the same manner (or similarly) as in Equation 12 above.

[0114] In operation S660, UE 140 may sequentially repeat operations one through five. In an embodiment, UE 140 may sequentially repeat operations one through five based on the recovered received signal from the serving cell. For example, UE 140 may repeat the entire received signal from the first operation that was immediately followed (or immediately) previously performed (e.g., the received signal for which FFT is applied in Equation 15). The signal is removed from the influence of the recovered received signal from the serving cell in the fifth operation performed immediately before (or immediately after), and then the first to fifth operations are performed. The entire received signal, after the influence of the recovered received signal from the serving cell has been removed, can be represented by the following equation.

[0115] [Equation 18] .

[0116] It can represent the entire received signal in the frequency domain after the effects of the recovered received signal from the serving cell have been removed.

[0117] In an embodiment, UE 140 may sequentially repeat the first to fifth operations until a convergence condition is met. For example, the convergence condition may be that the difference between the SINR of the first iteration operation and the SINR of the second iteration operation following the first iteration operation is less than a threshold SINR. For example, the convergence condition may be that the MSE of the serving cell's channel in the first iteration operation and the serving cell's channel in the second iteration operation following the first iteration operation is less than a specific value (e.g., a preset (or optionally, a given) value).

[0118] Figure 7 This is a flowchart of the third interference signal removal operation according to an embodiment. (Refer to...) Figure 7 The third interference signal removal operation 70 may include multiple operations S710 to S740.

[0119] Further reference Figure 1 In operation S710, UE 140 can compensate for subcarrier offset based on interference signals caused by interfering cells. In an embodiment, operation S710 can be combined with... Figure 6 The operation is the same as (or similar to) S610.

[0120] In operation S720, UE 140 can perform interference CRS channel estimation based on the compensated interference signal. In an embodiment, operation S720 can be combined with... Figure 6 The operation is the same as (or similar to) that of S620.

[0121] In operation S730, UE 140 can remove interference signals from the received signal from the serving cell based on interference CRS channel estimation. In an embodiment, operation S730 can be combined with... Figure 6 The operation is the same as (or similar to) that of S630.

[0122] In operation S740, UE 140 can perform serving CRS channel estimation based on the received signal after interference signals have been removed. In an embodiment, operation S740 can be combined with... Figure 6 The operation is the same as (or similar to) that of S640.

[0123] Figure 8 This is a flowchart illustrating an operation method of a wireless communication system according to an embodiment. (Refer to...) Figure 8 The operation method 80 of the wireless communication system may include multiple operations S810 and S820. BS 110a and UE 140a may be respectively Figure 1 Examples of BS 110 and UE140. (Compared to...) Figure 1 Redundant descriptions have been omitted.

[0124] In operation S810, UE 140a can receive bandwidth information of the interfering cell from BS 110a. In an embodiment, UE 140a can receive bandwidth information of the interfering cell via any of Radio Resource Control (RRC) signaling, Media Access Control-Control Element (MAC-CE) signaling, or Downlink Control Indicator (DCI) signaling.

[0125] In operation S820, UE 140a can perform interference signal removal operations corresponding to the bandwidth of the interfering cell based on bandwidth information. In this embodiment, UE 140a can perform the above-mentioned operation on the bandwidth of the interfering cell. Figures 3 to 7 The described interference signal removal operation. For example, when an interfering cell (e.g., Figure 1 When the bandwidth of BS 120 is narrower than that of BS 110a, which serves as the cell, UE 140a may perform the above-mentioned operation only on the bandwidth of the interfering cell. Figures 3 to 7 The interference signal removal operation is described. By performing interference signal removal operations corresponding to the bandwidth of the interfering cell based on the bandwidth information of the interfering cell, interference signals caused by the interfering cell can be effectively removed even when the bandwidth of the serving cell is different from that of the interfering cell, and the performance of UE 140a can be improved.

[0126] Figure 9 This is a block diagram of the UE according to an embodiment. Figure 9 The UE 90 implementation example can be applied to Figure 1 UE 140.

[0127] UE 90 may include a controller 91, a memory 92, processing circuitry 93, a radio frequency (RF) transceiver 94, and / or multiple antennas 94_1 to 94_n. The RF transceiver 94 can receive signals from antennas 94_1 to 94_n. Figure 1 The RF transceiver 94 can down-convert the received RF signal into an intermediate frequency (IF) signal or a baseband signal. The RF transceiver 94 can up-convert the IF signal or baseband signal output from the processing circuit 93 into an RF signal and transmit the RF signal through antennas 94_1 to 94_n.

[0128] The processing circuit 93 can generate a data signal by filtering, decoding, and / or digitizing the intermediate frequency signal or baseband signal, and can receive the data signal from the controller 91. The processing circuit 93 can encode, multiplex, and / or analogize the received data signal.

[0129] In this embodiment, the controller 91 can control the operation of the processing circuit 93, and the processing circuit 93 can perform the above-mentioned... Figures 1 to 8 The interference signal removal operation is described. For example, processing circuit 93 can divide the frequency offset difference between the serving cell and the interfering cell into subcarrier offset and residual frequency offset, and can perform interference signal removal operation based on the residual frequency offset, either compensating for the subcarrier offset or compensating for both the subcarrier offset and the residual frequency offset. The subcarrier offset has a value corresponding to an integer multiple of the SCS. Therefore, even when the frequency offset difference between the serving cell and the interfering cell is relatively large, the interference signal caused by the interfering cell can be effectively removed, and the performance of UE 90 can be improved. For example, processing circuit 93 can obtain the bandwidth information of the interfering cell by performing signaling with the serving cell via antennas 94_1 to 94_n. Furthermore, by performing an interference signal removal operation corresponding to the bandwidth of the interfering cell based on the bandwidth information of the interfering cell, processing circuit 93 can effectively remove the interference signal caused by the interfering cell even when the bandwidth of the serving cell is different from the bandwidth of the interfering cell. Therefore, the performance of UE 90 can be improved.

[0130] According to an embodiment, after the processing circuit 93 removes interference signals from the received signal, the UE 90 can perform network communication with the BS 110. For example, the UE 90 can (e.g., using the controller 91 and / or the processing circuit 93) generate a first signal, process the first signal to perform one or more of modulation, up-conversion, filtering, amplification, and / or encryption on the first signal, and transmit the processed first signal to the BS 110 via antennas 94_1 to 94_n. Additionally or optionally, the UE 90 can receive a second signal from the BS 110 via antennas 94_1 to 94_n, process the second signal (e.g., using the controller 91 and / or the processing circuit 93) to perform one or more of demodulation, down-conversion, filtering, amplification, and / or decryption on the second signal, and perform one or more further operations based on the processed second signal. For example, one or more further operations may include one or more of the following: providing the processed second signal to the corresponding application executed on UE 90, storing the processed second signal (e.g., storing it in memory 92), and (e.g., sending a response signal to BS 110 based on the processing result of the corresponding application executed on UE 90).

[0131] The controller 91 may additionally process data signals and execute programs and / or processes stored in the memory 92 to control the overall operation of the UE 90.

[0132] The memory 92 may have any data storage structure. For example, the memory 92 may include volatile memory devices (such as dynamic random access memory (DRAM) or static random access memory (SRAM)) and / or may also include non-volatile memory devices (such as flash memory or resistive random access memory (RRAM)).

[0133] Figure 10 This is a block diagram of an electronic device according to an embodiment. The electronic device 1000 according to the embodiment may be a UE.

[0134] Reference Figure 10 The electronic device 1000 may include a memory 1010, a processor unit 1020, an input / output controller 1040, a display 1050, an input device 1060, and / or a communication processor 1090. Multiple memories 1010 may also be provided. The individual components are described below.

[0135] The memory 1010 may include a program storage device 1011 for storing programs for controlling the operation of the electronic device 1000 and a data storage device 1012 for storing data generated during the execution of the program. The data storage device 1012 may store data required for (or otherwise used by) the operation of the application program 1013 and / or the data demodulation program 1014, and / or may store data generated during the operation of the application program 1013 and / or the data demodulation program 1014.

[0136] Program storage device 1011 may include application program 1013 and data demodulation program 1014. The program included in program storage device 1011 may be a set of instructions and may be referred to as an instruction set. Application program 1013 may include program code for performing various applications operating on electronic device 1000. That is, application program 1013 may include code (or commands) related to various applications driven by processor 1022.

[0137] Electronic device 1000 may include a communication processor 1090 that performs communication functions for voice and data communication. Peripheral device interface 1023 controls the connection between input / output controller 1040, communication processor 1090, processor 1022, and / or memory interface 1021. Processor 1022 can control (or communicate with) multiple BSs to provide corresponding services using at least one software program. In this case, processor 1022 can execute at least one program stored in memory 1010 to provide (or receive) services corresponding to that program.

[0138] Processor 1022 can execute the above reference. Figures 1 to 8 The interference signal removal operation is described. For example, the processor 1022 can divide the frequency offset difference between the serving cell and the interfering cell into subcarrier offset and residual frequency offset, and can perform interference signal removal operation based on the residual frequency offset, either compensating for the subcarrier offset or compensating for both the subcarrier offset and the residual frequency offset. The subcarrier offset has a value corresponding to an integer multiple of the SCS. Therefore, even when the frequency offset difference between the serving cell and the interfering cell is relatively large, the interference signal caused by the interfering cell can be effectively removed, and the performance of the electronic device 1000 can be improved. For example, the processor 1022 can obtain the bandwidth information of the interfering cell by performing signaling with the serving cell. Furthermore, by performing an interference signal removal operation corresponding to the bandwidth of the interfering cell based on the bandwidth information of the interfering cell, the processor 1022 can effectively remove the interference signal caused by the interfering cell even when the bandwidth of the serving cell is different from the bandwidth of the interfering cell. Therefore, the performance of the electronic device 1000 can be improved.

[0139] The input / output controller 1040 provides an interface between input / output devices (such as display 1050 and input device 1060) and the peripheral device interface 1023. Display 1050 can display status information, input text, moving images, and / or still images. For example, display 1050 can display information about applications driven by processor 1022.

[0140] Input device 1060 can provide input data to processor unit 1020 via input / output controller 1040, and the input data is generated by selection by electronic device 1000. Input device 1060 may include keypad with at least one hardware button, touchpad that senses touch information, etc. For example, input device 1060 can provide touch information (e.g., touch, touch motion and / or touch release detected by touchpad) to processor 1022 via input / output controller 1040.

[0141] Figure 11 This is a conceptual diagram illustrating an Internet of Things (IoT) network system with an applied embodiment.

[0142] Reference Figure 11 The IoT network system 2000 may include multiple IoT devices 2100, 2120, 2140 and / or 2160, access point 2200, gateway 2250, wireless network 2300 and / or server 2400. IoT can represent a network between things using wired and / or wireless communication.

[0143] IoT devices 2100, 2120, 2140, and / or 2160 can be grouped according to the characteristics of each IoT device. For example, IoT devices can be grouped into a home appliance group 2100, a home appliance / furniture group 2120, an entertainment group 2140, or a vehicle group 2160. IoT devices 2100, 2120, and 2140 can connect to a communication network or other IoT devices via access point 2200. Access point 2200 can be embedded in an IoT device. Gateway 2250 can modify the protocol to connect access point 2200 to an external wireless network. IoT devices 2100, 2120, and 2140 can connect to an external communication network via gateway 2250. Wireless network 2300 may include the Internet and / or a public network. IoT devices 2100, 2120, 2140 and 2160 can connect to a server 2400 that provides specific services via wireless network 2300, and users can use the services through at least one of IoT devices 2100, 2120, 2140 and 2160.

[0144] Each of the IoT devices 2100, 2120, 2140, and 2160 can execute the above reference. Figures 1 to 8The interference signal removal operation is described. For example, IoT devices 2100, 2120, 2140, and 2160 can divide the frequency offset difference between the serving cell and the interfering cell into subcarrier offset and residual frequency offset, and can perform interference signal removal operations based on the residual frequency offset, either compensating for the subcarrier offset or compensating for both the subcarrier offset and the residual frequency offset. The subcarrier offset has a value corresponding to an integer multiple of the SCS. Therefore, even when the frequency offset difference between the serving cell and the interfering cell is relatively large, the interference signal caused by the interfering cell can be effectively removed, and the performance of IoT devices 2100, 2120, 2140, and 2160 can be improved. For example, IoT devices 2100, 2120, 2140, and 2160 can obtain the bandwidth information of the interfering cell by performing signaling with the serving cell. Furthermore, by performing interference signal removal operations corresponding to the bandwidth of the interfering cell based on the bandwidth information of the interfering cell, IoT devices 2100, 2120, 2140, and 2160 can effectively remove interference signals caused by the interfering cell, even when the bandwidth of the serving cell differs from that of the interfering cell. Therefore, the performance of IoT devices 2100, 2120, 2140, and 2160 can be improved.

[0145] Conventional apparatuses and methods for compensating for inter-cell interference rely on enhanced inter-cell interference coordination (FeICIC) to remove interfering signals. However, FeICIC cannot remove interfering signals from the interfering cell when the frequency offset difference between the interfering cell and the serving cell is large. For example, in scenarios where one of these cells is a terrestrial cell and the other is a non-terrestrial cell (e.g., a satellite), a large frequency offset difference may occur due to the Doppler frequency shift corresponding to the higher traversable speed of the non-terrestrial cell. Therefore, conventional apparatuses and methods suffer from excessive inter-cell interference when high frequency offset differences are involved, resulting in poor communication performance.

[0146] However, according to embodiments, improved apparatus and methods are provided to remove or reduce inter-cell interference. For example, the improved apparatus and methods may involve obtaining the frequency offset difference between the serving cell and the interfering cell, and removing interfering signals from the received signal based on one or more of the subcarrier offset and / or residual frequency offset in the frequency offset difference. In doing so, the improved apparatus and methods can remove interfering signals from the received signal even when a high frequency offset difference is involved. Therefore, the improved apparatus and methods overcome the shortcomings of conventional apparatus and methods to at least improve communication performance.

[0147] According to embodiments, operations described herein, such as those performed via wireless communication system 10, BS 110, BS 120, BS 130, UE 140, BS 110a, UE 140a, UE 90, controller 91, processing circuitry 93, RF transceiver 94, electronic device 1000, processor unit 1020, input / output controller 1040, communication processor 1090, peripheral device interface 1023, processor 1022, memory interface 1021, IoT network system 2000, each of multiple IoT devices 2100, 2120, 2140 and / or 2160, access point 2200, gateway 2250 and / or server 2400, can be performed via the processing circuitry system. As used herein, the term "processing circuitry system" may mean, for example, hardware including logic circuitry; a hardware / software combination (such as a processor executing software); or a combination thereof. For example, the processing circuit system may more specifically include, but is not limited to, a central processing unit (CPU), an arithmetic logic unit (ALU), a graphics processing unit (GPU), a digital signal processor, a microcomputer, a field-programmable gate array (FPGA), a system-on-a-chip (SoC), a programmable logic unit, a microprocessor, an application-specific integrated circuit (ASIC), etc.

[0148] The various operations of the methods described above can be performed by any suitable device capable of performing the operations (such as the processing circuitry system discussed above). For example, as mentioned above, the operations of the methods described above can be performed by various hardware and / or software implemented in some form of hardware (e.g., processor, ASIC, etc.).

[0149] The software may include an ordered list of executable instructions for implementing logical functions and may be embodied in any processor-readable medium for use by or in conjunction with an instruction execution system, device, or apparatus (such as a single-core or multi-core processor or a system containing a processor).

[0150] The blocks or operations and / or functions of the methods or algorithms described in conjunction with the embodiments disclosed herein may be embodied directly in hardware, in software modules executed by a processor, or a combination of both. If implemented in software, the functions may be stored as one or more instructions or code on a physical, non-transitory computer-readable medium (e.g., memory 92, memory 1010, etc.), or transferred on a physical, non-transitory computer-readable medium (e.g., memory 92, memory 1010, etc.). The software modules may reside in random access memory (RAM), flash memory, read-only memory (ROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), registers, hard disks, removable disks, CD ROMs, or any other form of storage medium known in the art.

[0151] Although the inventive concept has been specifically shown and described with reference to embodiments thereof, it will be understood that various changes in form and detail may be made therein without departing from the spirit and scope of the appended claims.

Claims

1. A method for operating a user equipment communicating with a base station, the method comprising: The frequency offset difference between the serving cell and the interfering cell is calculated based on the first frequency offset of the serving cell and the second frequency offset of the interfering cell. The frequency offset difference includes subcarrier offset and residual frequency offset. The subcarrier offset is an integer multiple of the subcarrier spacing. as well as Interference signals are removed from the received signal received by the user equipment by compensating for the frequency offset difference based on the residual frequency offset.

2. The operating method as described in claim 1, wherein, The steps for removing interference signals include: removing interference signals by performing a first interference signal removal operation, a second interference signal removal operation, or a third interference signal removal operation; The first interference signal removal operation is a repeated compensation operation for the frequency offset difference. The second interference removal operation is a repeated subcarrier offset compensation operation; and The third interference removal operation is an operation that compensates for the subcarrier offset only once.

3. The operation method as described in claim 2, wherein, The steps for removing interference signals include: in response to determining that the absolute value of the residual frequency offset is greater than or equal to a first threshold, removing the interference signal by performing a first interference signal removal operation, the first interference signal removal operation including: The first operation is to compensate for the frequency offset difference based on the interference signal in order to obtain the compensated interference signal. The second operation is to perform interfering cell-specific reference signal channel estimation based on the compensated interference signal; The third step is to remove the interference signal from the received signal based on the specific reference signal channel estimation of the interfering cell to obtain the updated received signal. The fourth operation is to perform serving cell-specific reference signal channel estimation based on the updated received signal; The fifth operation involves recovering the received signal based on the serving cell-specific reference signal channel estimation to obtain the recovered received signal; and The first to fifth operations are repeated sequentially based on the recovered received signal.

4. The operating method as described in claim 3, wherein, The steps of sequentially repeating the first to fifth operations include: sequentially repeating the first to fifth operations until the convergence condition is met; and The convergence condition is that the difference between the signal-to-interference-plus-noise ratio of the first iteration and the signal-to-interference-plus-noise ratio of the second iteration is less than the threshold signal-to-interference-plus-noise ratio, and the second iteration occurs after the first iteration.

5. The operating method as described in claim 2, wherein, The steps for removing interference signals include: in response to determining that the absolute value of the residual frequency offset is less than a first threshold and that there is a conflict with a reference signal specific to the interfering cell, removing the interference signal by performing a second interference signal removal operation, the second interference signal removal operation including: The first operation is to compensate for the subcarrier offset based on the interference signal in order to obtain the compensated interference signal. The second operation is to perform interfering cell-specific reference signal channel estimation based on the compensated interference signal; The third step is to remove the interference signal from the received signal based on the specific reference signal channel estimation of the interfering cell to obtain the updated received signal. The fourth operation is to perform serving cell-specific reference signal channel estimation based on the updated received signal; The fifth operation involves recovering the received signal based on the serving cell-specific reference signal channel estimation to obtain the recovered received signal; and The first to fifth operations are repeated sequentially based on the recovered received signal.

6. The operating method as described in claim 2, wherein, The steps for removing interference signals include: in response to determining that the absolute value of the residual frequency offset is less than a first threshold and there is no interference cell-specific reference signal conflict, removing the interference signal by performing a third interference signal removal operation, the third interference signal removal operation including: The subcarrier offset is compensated based on the interference signal to obtain the compensated interference signal; Perform cell-specific reference signal channel estimation based on the compensated interference signal; Interference signals are removed from the received signal based on the channel estimation of the specific reference signal of the interfering cell to obtain an updated received signal; and Perform serving cell-specific reference signal channel estimation based on the updated received signal.

7. The operating method according to any one of claims 1 to 6, wherein, The subcarrier offset is the largest integer less than or equal to twice the normalized frequency offset, which is obtained by normalizing the frequency offset difference by subcarrier spacing. and The residual frequency offset is obtained by subtracting the subcarrier offset from the normalized frequency offset.

8. The operating method according to any one of claims 1 to 6, further comprising: Receive bandwidth information of interfering cells from the base station. The step of removing interference signals includes removing interference signals corresponding to the bandwidth of the interfering cell based on the bandwidth information.

9. The operating method as described in claim 8, wherein, The steps of receiving the bandwidth information include receiving the bandwidth information via one of radio resource control signaling, media access control-control element signaling, and downlink control indicator signaling.

10. The operating method as described in claim 1, wherein, The base station supports non-terrestrial networks.

11. A method for operating a user equipment communicating with a base station, the method comprising: Detect the first frequency offset of the serving cell provided by the base station and the second frequency offset of the interfering cell; The normalized frequency offset is calculated by normalizing the frequency offset difference with the subcarrier spacing. The frequency offset difference is the difference between the first frequency offset and the second frequency offset. The residual frequency offset and subcarrier offset are calculated based on the normalized frequency offset. The subcarrier offset is an integer multiple of the subcarrier spacing. Determine whether the absolute value of the residual frequency offset is greater than or equal to the threshold; In response to determining that the absolute value of the residual frequency offset is greater than or equal to a threshold, a first interference signal removal operation is performed on the received signal received by the user equipment to repeatedly compensate for the frequency offset difference. In response to the determination that the absolute value of the residual frequency offset is less than a threshold, it is determined whether there is a conflict of the interfering cell-specific reference signal. The conflict of the interfering cell-specific reference signal is caused by the overlap of the cell-specific reference signal position of the interfering cell with the cell-specific reference signal position of the serving cell. In response to the determination that there is a specific reference signal conflict in the interfering cell, a second interference signal removal operation is performed on the received signal to repeatedly compensate for subcarrier offset; as well as In response to the determination that there is no interference cell-specific reference signal conflict, a third interference removal operation is performed on the received signal to compensate for the subcarrier offset only once.

12. The operating method as described in claim 11, wherein, The threshold is based on one of the following: the received power of the reference signal, the received signal strength indicator, and the signal-to-interference-plus-noise ratio.

13. The operating method as described in claim 11 or 12, further comprising: The first frequency offset is set to 0 by adjusting the center frequency based on the first frequency offset. The first interference signal removal operation includes: The first step involves compensating for the frequency offset difference based on the interference signal to obtain the compensated interference signal. The interference signal is caused by the interfering cell. The second operation involves performing channel estimation for a specific reference signal of the interfering cell based on the compensated interference signal. The third step involves removing interference signals from the received signal based on the channel estimation of the interference cell-specific reference signal to obtain an updated received signal. The fourth operation involves performing serving cell-specific reference signal channel estimation based on the updated received signal. The fifth operation involves recovering the received signal based on the serving cell-specific reference signal channel estimation, in order to obtain the recovered received signal. The first to fifth operations are repeated sequentially based on the recovered received signal.

14. The operating method as described in claim 11 or 12, further comprising: The first frequency offset is set to 0 by adjusting the center frequency based on the first frequency offset. The second interference signal removal operation includes: The first operation involves compensating for subcarrier offset based on the interference signal to obtain the compensated interference signal. The interference signal is caused by the interfering cell. The second operation involves performing channel estimation for a specific reference signal of the interfering cell based on the compensated interference signal. The third step involves removing interference signals from the received signal based on the channel estimation of the interference cell-specific reference signal to obtain an updated received signal. The fourth operation involves performing serving cell-specific reference signal channel estimation based on the updated received signal. The fifth operation involves recovering the received signal from the serving cell based on the serving cell-specific reference signal channel estimation, to obtain the recovered received signal. The first to fifth operations are repeated sequentially based on the recovered received signal.

15. The operating method as described in claim 14, wherein, The steps of sequentially repeating the first to fifth operations include: sequentially repeating the first to fifth operations until the convergence condition is met; and The convergence condition is that the difference between the signal-to-interference-plus-noise ratio of the first iteration and the signal-to-interference-plus-noise ratio of the second iteration is less than the threshold signal-to-interference-plus-noise ratio, and the second iteration occurs after the first iteration.

16. The operating method as described in claim 11 or 12, further comprising: The first frequency offset is set to 0 by adjusting the center frequency based on the first frequency offset. The third interference signal removal operation includes: The compensated interference signal is obtained by compensating for subcarrier offset based on the interference signal. The interference signal is caused by the interfering cell. Perform interfering cell-specific reference signal channel estimation based on the compensated interference signal. Based on the interference cell-specific reference signal channel estimation, interference signals are removed from the received signal to obtain an updated received signal, and Perform serving cell-specific reference signal channel estimation based on the updated received signal.

17. The operating method as described in claim 11 or 12, wherein, The steps for calculating the residual frequency offset and subcarrier offset include: The subcarrier offset is calculated as the largest integer less than or equal to twice the normalized frequency offset; and... The residual frequency offset is calculated as the value obtained by subtracting the subcarrier offset from the normalized frequency offset.

18. The operating method as described in claim 11 or 12, further comprising: Bandwidth information of the interfering cell is received from the base station via one of the radio resource control signaling, media access control-control element signaling, and downlink control indicator signaling. The first interference signal removal operation, the second interference signal removal operation, or the third interference signal removal operation includes removing the interference signal corresponding to the bandwidth of the interfering cell based on the bandwidth information.

19. A user equipment communicating with a base station, the user equipment comprising: Multiple antennas are configured to transmit signals to and receive signals from the base station; as well as The processing circuit system is configured as follows: The frequency offset difference between the serving cell and the interfering cell is calculated based on the first frequency offset of the serving cell and the second frequency offset of the interfering cell. This frequency offset difference includes subcarrier offset and residual frequency offset. The serving cell is provided by the base station, and the subcarrier offset is an integer multiple of the subcarrier spacing. Interference removal is performed by compensating for the frequency offset difference based on the residual frequency offset to remove interference signals from the received signal, which is caused by the interfering cell and is received by the user equipment.

20. The user equipment as claimed in claim 19, wherein, Interference signal removal operations include one of the following: The first interference signal removal operation involves repeatedly compensating for the frequency offset difference. The second interference removal operation involves repeated compensation for subcarrier offset, and The third interference removal operation only compensates for one subcarrier offset; and The processing circuit system is configured as follows: Determine whether the absolute value of the residual frequency offset is greater than or equal to a threshold. In response to determining that the absolute value of the residual frequency offset is greater than or equal to a threshold, a first interference signal removal operation is performed. In response to the determination that the absolute value of the residual frequency offset is less than a threshold, it is determined whether there is an interfering cell-specific reference signal conflict to obtain a determination result. The interfering cell-specific reference signal conflict is based on the overlap between the cell-specific reference signal position of the interfering cell and the cell-specific reference signal position of the serving cell. Based on the determined result, perform a second or third interference signal removal operation.

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