Apparatus and method for radio resource muting for interference signal measurement in wireless communication system

Abstract

The present disclosure generally relates to a wireless communication system, and more specifically to a method and apparatus for muting a wireless resource for measuring interference signals in a wireless communication system. A method of operation of a first base station according to one embodiment of the present disclosure exchanges information related to the configuration of a wireless resource for measuring Cross-Link Interference (CLI) with a second base station, sets a semi-static configuration of a muting resource to be applied when transmitting an uplink (UL) to a terminal, performs a measurement of a CLI reference signal (RS) received from the second base station in the muting resource, and sets the number of muting symbols applied when calculating the Transport Block Size (TBS) to be fixed or semi-static.

Description

Technology Field

[0001] The present disclosure generally relates to wireless communication systems, and more specifically to a method and apparatus for wireless resource muting for measuring interference signals in a wireless communication system. Background Technology

[0002] Mobile communication technology evolves in cycles of approximately 10 years, and with the emergence of a new generation, the performance and capabilities of communication have advanced dramatically. Since the completion of the 5G NR (New Radio) standard, the fifth-generation mobile communication technology, in June 2018, global attention has naturally turned toward the next generation, 6G. While communication systems from 2G to 5G have evolved with a focus on communication performance, such as improved transmission speeds and reduced latency, 6G is expected to present a new paradigm for providing innovative services while offering even higher data transmission speeds, ultra-low latency, and massive connectivity than current 5G.

[0003] At the 44th meeting of the International Telecommunication Union (ITU) Working Group on Mobile Communication (ITU-R WP5D), held in Geneva, Switzerland in June 2023, the next-generation mobile communication expected to be commercialized around 2030 was named 'IMT-2030,' and the '6G Vision' recommendations for the IMT-2030 framework were announced. These recommendations include 6G use scenarios and key performance indicators that present 6G services and technical characteristics. Representative 6G use scenarios consist of three extended from existing 5G (Immersive Communication, Hyper reliable and low-latency communication, and Massive communication) and three newly introduced for 6G (Ubiquitous connectivity, Integrated AI and communication, and Integrated sensing and communication). Therefore, in 6G, IBFD (Inband Full Duplex), which enables Immersive Communication through improved spectrum efficiency; SBFD (Subband Full Duplex), which expands uplink (UL) transmission rates and UL coverage; and ISAC (Integrated Sensing and Communication), which provides new sensing services, are attracting attention as key technologies that will represent 6G.

[0004] ISAC tightly integrates communication and sensing technologies, enabling them to operate complementarily and simultaneously provide data transmission and object sensing capabilities. In 6G, not only the millimeter wave band introduced in existing 5G but also the Upper-mid and Sub-THz bands are scheduled to be newly introduced. The utilization of these high frequency bands enables wider bandwidth and large-scale antenna arrays in 6G, facilitating the implementation of high-precision and high-resolution sensing. Therefore, 6G holds the potential to provide new services that were previously impossible, such as autonomous driving, environmental monitoring, and digital twins, through ISAC technology.

[0005] ISAC technology can be broadly classified into Communication-Aided Sensing (CAS) and Sensing-Aided Communication (SAC). CAS is a concept that performs sensing using mobile communication infrastructure, while SAC is a method that utilizes sensing results to improve communication performance. In CAS, sensing methods are broadly categorized into Monostatic sensing, Bistatic sensing, and Multistatic sensing. Currently, the ongoing 3GPP RAN1 standardization activities place higher priority on supporting Monostatic sensing and Bistatic sensing using base stations and terminals.

[0006] Meanwhile, ISAC supports various levels of integration. Communication and sensing systems can share the same location, spectrum, and hardware; they can design and use separate, optimized signal waveforms for each, or design a common signal waveform to utilize together. Among these integration methods, the approach of sharing location, spectrum, and hardware is considered the most reasonable and effective method for 6G ISAC systems. However, in this case, various interferences may occur between communication and sensing.

[0007] First, Mutual Interference (MI) is the most representative type of interference that occurs when sensing and communication are performed simultaneously. It is a phenomenon where the sensing signal from a base station interferes with the communication terminal, while conversely, the signal from the communication terminal increases the noise level of the base station's sensing receiver. Second, Crosstalk interference is interference that occurs between different network nodes (e.g., distributed antennas, repeaters, terminals) in an ISAC system. For instance, when one base station transmits a Downlink (DL) sensing signal and another base station transmits a DL communication signal, the sensing base station must receive the echo signal reflected from the sensing target simultaneously with the transmission of the DL sensing signal. However, the DL communication signal transmitted by the communication base station acts as interference to the sensing base station's reception of the echo signal, which can degrade sensing performance. Third, Self-Interference (SI) can occur when implementing a Monostatic Sensing-based ISAC system. It is interference caused by a collision between a transmitted signal and an echo signal reflected back by a target, which can degrade the accuracy of the sensing signal. Fourth, clutter is an interference signal that is problematic even in existing radar systems, and signals reflected by unintended moving targets or surrounding scatterers can degrade sensing performance.

[0008] Meanwhile, Time Division Duplex (TDD) is a half-duplex method in which a base station performs transmission and reception within the same frequency band by dividing them into time slots. TDD is currently widely used in commercial 5G NR and divides time domain resources into DL and UL. However, if limited time resources are allocated to UL in TDD, problems such as reduced UL coverage, increased communication latency, and reduced UL capacity occur. To address these limitations, the Study Item (SI) of 3GPP Release 18 conducted research on full-duplex communication, in which DL and UL coexist within the existing TDD band, as one of the key features of 5G-Advanced. More specifically, the necessity and feasibility of supporting Subband Non-Overlapping Full Duplex (SBFD) were investigated.

[0009] In the 3GPP Release 18 NR Duplex SI standardization work, specifically, deployment scenarios applicable to SBFD and dynamic / flexible TDD were identified, and research and evaluation were conducted on the feasibility of SBFD and its performance, including User Perceived Throughput (UPT), latency, and UL coverage. The results of this SI research are summarized in 3GPP TR 38.858. As concluded in 3GPP TR 38.858, it was determined that in 3GPP Release 19, it is necessary to specify SBFD operation at the base station side within the TDD carrier, methods for handling Cross-Link Interference (CLI) between base stations and between terminals for SBFD operation, and Radio Frequency (RF) requirements for SBFD operation at the base station. Consequently, standardization of the 3GPP Release 19 Work Item (WI) for SBFD specification is currently underway.

[0010] In SBFD, just as in Dynamic TDD, inter-base station CLIs and inter-terminal CLIs can occur. Current standardization efforts are promoting the standardization of a technique that mutes UL radio resources during Physical Uplink Shared Channel (PUSCH) transmission as a method for handling inter-base station CLIs. This aims to clearly measure and analyze inter-base station CLIs by ensuring that the signal transmitted for measuring inter-base station CLIs does not conflict with the UL signal transmitted by the terminal. For example, by muting some UL transmission resources according to a predefined pattern, base stations can receive inter-base station CLI reference signals (RS) without interference. Using this, base stations can calculate the covariance matrix of the inter-base station CLIs and apply it to a Minimum Mean Square Error and Interference Rejection Combiner (MMSE-IRC) receiver to suppress inter-base station CLIs.

[0011] In summary, in ISAC, when a base station performs monostatic sensing, the echo signal reception performance of the sensing base station is degraded by crosstalk interference (i.e., signals from adjacent base stations), and in SBFD, the UL reception performance of a base station can be degraded by inter-base station CLI (i.e., DL interference signals from adjacent base stations). Therefore, an effective radio resource muting method is required to resolve these interference problems. The problem to be solved

[0012] Based on the discussion above, the present disclosure provides an apparatus and method for accurately measuring cross-link interference (CLI) signals between base stations in a wireless communication system.

[0013] In addition, the present disclosure provides an apparatus and method for improving interference signal measurement performance by muting wireless resources during uplink transmission in a wireless communication system.

[0014] In addition, the present disclosure provides an apparatus and method for performing stable communication without recalculating the Transport Block Size (TBS) despite dynamic changes in muting symbols in a wireless communication system.

[0015] In addition, the present disclosure provides an apparatus and method for solving a power mismatch problem between a muting symbol and a phase tracking reference signal (PT-RS) in a wireless communication system. means of solving the problem

[0016] According to various embodiments of the present disclosure, a method of operation of a first base station for measuring interference signals in a wireless communication system may exchange information related to the configuration of wireless resources for measuring Cross-Link Interference (CLI) with a second base station, set a semi-static configuration of a muting resource to be applied when transmitting an uplink (UL) to a terminal, perform a measurement of a CLI reference signal (RS) received from the second base station in the muting resource, and set the number of muting symbols applied when calculating the Transport Block Size (TBS) to be fixed or semi-static.

[0017] According to various embodiments of the present disclosure, a method of operation of a terminal for measuring interference signals in a wireless communication system receives a semi-static configuration of a muting resource to be applied during uplink (UL) transmission from a first base station, mutes a resource specified during UL transmission according to the semi-static configuration, and can transmit data based on the number of muting symbols set as fixed or semi-static that are applied when calculating the transmission block size (TBS).

[0018] According to various embodiments of the present disclosure, a first base station for measuring interference signals in a wireless communication system includes a transceiver and a processor operably connected to the transceiver, and the processor exchanges information related to the configuration of wireless resources for measuring cross-link interference (CLI) with a second base station, sets a semi-fixed configuration of a muting resource to be applied when transmitting uplink (UL) to a terminal, performs a measurement of a CLI reference signal (RS) received from the second base station in the muting resource, and can set the number of muting symbols applied when calculating the transmission block size (TBS) to be fixed or semi-fixed.

[0019] According to various embodiments of the present disclosure, a terminal for measuring interference signals in a wireless communication system includes a transceiver and a processor operably connected to the transceiver, and the processor receives a semi-fixed configuration of muting resources to be applied during uplink (UL) transmission from a first base station, mutes resources specified during UL transmission according to the semi-fixed configuration, and can transmit data based on the number of muting symbols set as fixed or semi-fixed to be applied when calculating the Transport Block Size (TBS). Effects of the invention

[0020] The apparatus and method according to various embodiments of the present disclosure enable stable data transmission without the burden of recalculation even in an environment where muting symbols change dynamically by applying a semi-fixed transmission block size calculation method.

[0021] In addition, the apparatus and method according to various embodiments of the present disclosure can improve the accuracy of phase noise estimation and prevent degradation of communication quality by maintaining power consistency of the phase tracking reference signal through differentiated power boosting or symbol relocation techniques in muting symbols.

[0022] The effects obtainable from the present disclosure are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present disclosure belongs from the description below. Brief explanation of the drawing

[0023] FIG. 1 illustrates an ISAC use case according to various embodiments of the present disclosure. FIG. 2 illustrates the interference types of an ISAC system according to various embodiments of the present disclosure. FIG. 3 illustrates an example of inter-base station cross-link interference (gNB-to-gNB CLI) of an SBFD according to various embodiments of the present disclosure. FIG. 4 illustrates an example of receiving a CLI reference signal between base stations (gNB-to-gNB CLI RS) through uplink signal muting according to various embodiments of the present disclosure. FIG. 5 illustrates a method for avoiding overlap between PT-RS and muting symbols through muting symbol deactivation according to one embodiment of the present disclosure. FIG. 6 illustrates a method for avoiding overlap with muting symbols through PT-RS deactivation according to one embodiment of the present disclosure. FIG. 7 illustrates a method for avoiding overlap between PT-RS and muting symbols through muting symbol rearrangement according to one embodiment of the present disclosure. FIG. 8 illustrates a method for avoiding overlap with muting symbols through PT-RS rearrangement according to one embodiment of the present disclosure. FIG. 9 is a flowchart illustrating the operation method of a first base station for measuring an interference signal in a wireless communication system according to one embodiment of the present disclosure. FIG. 10 is a flowchart illustrating a method of operation of a terminal for measuring an interference signal in a wireless communication system according to one embodiment of the present disclosure. FIG. 11 illustrates a configuration diagram of a terminal in a wireless communication system according to various embodiments of the present disclosure. FIG. 12 illustrates a configuration diagram of a base station in a wireless communication system according to various embodiments of the present disclosure. Specific details for implementing the invention

[0024] The terms used in this disclosure are used merely to describe specific embodiments and are not intended to limit the scope of other embodiments. A singular expression may include a plural expression unless the context clearly indicates otherwise. Terms used herein, including technical or scientific terms, may have the same meaning as generally understood by those skilled in the art described in this disclosure. Terms used in this disclosure that are defined in a general dictionary may be interpreted as having the same or similar meaning as they have in the context of the relevant technology, and are not to be interpreted in an ideal or overly formal sense unless explicitly defined in this disclosure. In some cases, even terms defined in this disclosure are not to be interpreted to exclude the embodiments of this disclosure.

[0025] In the various embodiments of the present disclosure described below, a hardware-based approach is described as an example. However, since the various embodiments of the present disclosure include techniques using both hardware and software, the various embodiments of the present disclosure do not exclude a software-based approach.

[0026] Additionally, in the detailed description and claims of the present disclosure, “at least one of A, B, and C” may mean “only A,” “only B,” “only C,” or “any combination of A, B, and C.” Additionally, “at least one of A, B, or C” or “at least one of A, B, and / or C” may mean “at least one of A, B, and C.”

[0027] The present disclosure relates to a method and apparatus for radio resource muting for measuring interference signals in a wireless communication system. Specifically, the present disclosure describes a technology for performing stable and efficient interference signal measurement through radio resource muting for measuring cross-link interference between base stations in a wireless communication system, a semi-fixed transmission block size calculation method, and a method for resolving power mismatch between a phase tracking reference signal and a muting symbol.

[0028] Terms referring to signals, channels, control information, network entities, and device components used in the following description are examples provided for the convenience of explanation. Accordingly, the present disclosure is not limited to the terms described below, and other terms having equivalent technical meanings may be used.

[0029] Additionally, the present disclosure describes various embodiments using terms used in some communication standards (e.g., 3GPP (3rd Generation Partnership Project)), but this is merely illustrative. Various embodiments of the present disclosure can be easily modified and applied to other communication systems.

[0030] FIG. 1 illustrates an ISAC use case according to various embodiments of the present disclosure.

[0031] Mobile communication technology evolves in cycles of approximately 10 years, and with the emergence of a new generation, the performance and capabilities of communication have advanced dramatically. Since the completion of the 5G NR (New Radio) standard, the fifth-generation mobile communication technology, in June 2018, global attention has naturally turned toward the next generation, 6G. At the 44th session of the International Telecommunication Union (ITU) Working Group on Mobile Communication (ITU-R WP5D) held in Geneva, Switzerland, in June 2023, the next-generation mobile communication expected to be commercialized around 2030 was named 'IMT-2030,' and the '6G Vision' recommendation for the IMT-2030 framework was announced. This recommendation includes 6G usage scenarios and key performance indicators that present 6G services and technical characteristics.

[0032] Representative 6G usage scenarios consist of three extended from existing 5G (Immersive Communication, Hyper reliable and low-latency communication, Massive communication) and three newly introduced in 6G (Ubiquitous connectivity, Integrated AI and communication, Integrated sensing and communication). Among these, ISAC (Integrated Sensing and Communication) is attracting attention as a core 6G technology that integrates communication and sensing.

[0033] ISAC closely integrates communication and sensing technologies, enabling them to operate complementarily and simultaneously provide data transmission and object sensing capabilities. In 6G, not only the millimeter wave band introduced in 5G but also the upper-mid and sub-terahertz (Sub-THz) bands are scheduled to be newly introduced. The utilization of these high-frequency bands enables wider bandwidth and large-scale antenna arrays in 6G, facilitating the implementation of high-precision and high-resolution sensing. Furthermore, high-frequency bands such as millimeter waves and sub-terahertz waves exhibit a characteristic where the signal attenuation rate varies depending on changes in oxygen and water vapor content. While this characteristic may be a disadvantage in terms of communication, it can be usefully applied to sensing weather conditions.

[0034] Referring to Figure 1, representative use cases achievable through ISAC technology are presented. First, in the field of autonomous driving, safe autonomous driving can be supported by performing high-precision sensing of obstacles, pedestrians, and other vehicles simultaneously with real-time communication between the vehicle and the surrounding environment. Second, in the field of environmental monitoring, communication infrastructure can be utilized to continuously detect atmospheric conditions, weather conditions, and environmental pollution, and related data can be transmitted in real time. Third, in the field of digital twins, precise sensing information regarding physical space is collected and transmitted via a communication network to recreate it in a virtual space in real time, thereby enabling applications such as smart cities and smart factories. This ISAC technology has the potential to provide new services that were previously impossible and is expected to bring innovation to various industrial sectors as a core technology of the 6G era.

[0035] FIG. 2 illustrates the interference types of an ISAC system according to various embodiments of the present disclosure.

[0036] ISAC technology can be broadly classified into Communication-Aided Sensing (CAS) and Sensing-Aided Communication (SAC). CAS is a concept that performs sensing using mobile communication infrastructure, while SAC is a method that utilizes sensing results to improve communication performance. In CAS, sensing methods are broadly categorized into Monostatic sensing, Bistatic sensing, and Multistatic sensing. Currently, the ongoing 3GPP RAN1 standardization activities place higher priority on supporting Monostatic sensing and Bistatic sensing using base stations and terminals.

[0037] Meanwhile, ISAC supports various levels of integration. Communication and sensing systems can share the same location, spectrum, and hardware; they can design and use separate, optimized signal waveforms for each, or design a common signal waveform to utilize together. Among these integration methods, the approach of sharing location, spectrum, and hardware is considered the most reasonable and effective method for 6G ISAC systems. However, in this case, various interferences may occur between communication and sensing.

[0038] Referring to FIG. 2, various types of interference that may occur in an ISAC system are presented. FIG. 2 illustrates a first ISAC base station (ISAC-BS 1), a second ISAC base station (ISAC-BS 2), a third ISAC base station (ISAC-BS 3), a communication terminal (201), a sensing target (202), a communication signal (203), and a sensing signal (204).

[0039] First, mutual interference (MI) is the most representative type of interference that occurs when sensing and communication are performed simultaneously. In FIG. 2, the phenomenon in which the sensing signal (204) of the first ISAC base station causes interference to the communication terminal (201), and conversely, the communication signal (203) of the communication terminal (201) increases the noise level of the sensing receiver of the first ISAC base station, corresponds to mutual interference.

[0040] Second, crosstalk interference is interference that occurs between different network nodes (e.g., distributed antennas, repeaters, terminals) in an ISAC system. In FIG. 2, the second ISAC base station transmits a downlink (DL) sensing signal (204), and the third ISAC base station transmits a DL communication signal (203). The second ISAC base station must receive an echo signal reflected from a sensing target (202) simultaneously with transmitting the DL sensing signal; however, the DL communication signal transmitted by the third ISAC base station acts as interference to the second ISAC base station's reception of the echo signal, which may degrade the sensing performance. Additionally, the sensing signal transmitted by the second ISAC base station may also interfere with the reception performance of the communication terminal (201). Both of these types of interference correspond to crosstalk interference.

[0041] Third, self-interference (SI) can occur when implementing a monostatic sensing-based ISAC system. As shown in Figure 2, this is interference that occurs when a transmitted signal collides with an echo signal reflected back by a target, such as the third ISAC base station, and can degrade the accuracy of the sensing signal.

[0042] Fourth, clutter is an interference signal that is problematic even in existing radar systems, and as shown in Fig. 2, signals reflected by unintended moving targets or surrounding scatterers can degrade sensing performance.

[0043] FIG. 3 illustrates an example of inter-base station cross-link interference (gNB-to-gNB CLI) of an SBFD according to various embodiments of the present disclosure.

[0044] Time Division Duplex (TDD) is a half-duplex method in which a base station performs transmission and reception within the same frequency band by dividing them into time slots. TDD is currently widely used in commercial 5G NR and divides time domain resources into downlink (DL) and uplink (UL). However, if limited time resources are allocated to the UL in TDD, problems such as reduced UL coverage, increased communication latency, and reduced UL capacity occur. To address these limitations, the Study Item (SI) of 3GPP Release 18 conducted research on full-duplex communication, where DL and UL coexist within the existing TDD band, as one of the key features of 5G-Advanced. More specifically, the necessity and feasibility of supporting Subband Non-Overlapping Full Duplex (SBFD) were investigated.

[0045] Referring to FIG. 3, various scenarios of cross-link interference between base stations (gNB-to-gNB CLI) that may occur in an SBFD system are presented. At the top of FIG. 3, a first base station (301) and a second base station (302), and terminals 1 (303) and 2 (304) connected to each base station are shown. Here, the first base station (301) operates as an Aggressor gNB (A-gNB) that generates an interference signal, and the second base station (302) operates as a Victim gNB (V-gNB) that is affected by the interference.

[0046] Figure 3 presents three representative CLI occurrence cases. Case 1 illustrates an interference scenario that occurs when both base stations operate in SBFD mode. When the first base station (301) operates in SBFD mode and performs DL transmission in a specific subband, and the second base station (302) also operates in SBFD mode and performs UL reception in the same time-frequency resource, the DL signal of the first base station acts as interference on the UL reception of the second base station, causing cross-link interference.

[0047] Case 2 represents interference occurring between two SBFD base stations similar to Case 1, but with a different time-frequency resource allocation pattern. Even if the first base station (301) and the second base station (302) use different SBFD configurations, CLI between base stations can occur in frequency domains where DL and UL overlap at the same time.

[0048] Case 3 illustrates an interference scenario that occurs when one base station operates in the existing TDD mode and another base station operates in the SBFD mode. When the first base station (301) performs DL transmission in the entire band in TDD mode, and the second base station (302) performs UL reception in some subbands in SBFD mode, the DL signal of the first base station may cause strong interference with the UL reception of the second base station.

[0049] Such inter-base station CLIs can significantly degrade the performance of SBFD systems, and therefore, effective interference measurement and mitigation techniques are required. The radio resource muting method proposed in this disclosure can be utilized to accurately measure and mitigate such inter-base station CLIs.

[0050] FIG. 4 illustrates an example of receiving a CLI reference signal between base stations (gNB-to-gNB CLI RS) through uplink signal muting according to various embodiments of the present disclosure.

[0051] In SBFD, just as in Dynamic TDD, CLIs between base stations and CLIs between terminals can occur. The ongoing 3GPP Release 19 SBFD Work Item (WI) standardization is promoting the standardization of a technique for muting UL radio resources during Physical Uplink Shared Channel (PUSCH) transmission as a method for handling CLIs between base stations. This is intended to clearly measure and analyze CLIs between base stations by ensuring that the signal transmitted to measure CLIs between base stations does not conflict with the UL signal transmitted by the terminal.

[0052] Referring to FIG. 4, a wireless resource muting procedure for measuring CLI between base stations is presented. FIG. 4 illustrates a first base station (401) generating an interference signal, a second base station (402) affected by interference, a terminal 1 (403) connected to the first base station, and a terminal 2 (404) connected to the second base station.

[0053] To measure CLI between base stations, the first base station (401) and the second base station (402) exchange information regarding the configuration of wireless resources for CLI measurement. The first base station (401) operates as an Aggressor gNB (A-gNB) that generates an interference signal and transmits CLI-RS. The second base station (402) operates as a Victim gNB (V-gNB) affected by interference and performs measurement of CLI in muting resources.

[0054] The second base station (402) can set a muting resource to be applied when the terminal 2 (404) transmits UL. To do this, the second base station (402) sets a semi-static configuration of the UL muting resource for the terminal 2 (404). Accordingly, when transmitting UL, the terminal 2 (404) mutes the specified resource according to the semi-static configuration of the base station.

[0055] By muting some UL transmission resources according to a predefined pattern in FIG. 4, the second base station (402) can receive the CLI-RS transmitted by the first base station (401) without interference with the UL signal of terminal 2 (404). The second base station (402) can suppress the CLI between base stations by calculating the covariance matrix of the CLI between base stations using the received CLI-RS and applying it to a Minimum Mean Square Error and Interference Rejection Combiner (MMSE-IRC) receiver.

[0056] The UL muting resource may partially or entirely overlap with the CLI-RS resource transmitted by the first base station (401), but may not overlap. The second base station (402) is assumed to perform CLI measurements based on the muting resource. If only a part of the muting resource overlaps with the CLI-RS, the entire muting resource may be used for CLI measurements, but only the CLI-RS resource that overlaps with the muting resource may be used.

[0057] FIG. 5 illustrates a method for avoiding overlap between PT-RS and muting symbols through muting symbol deactivation according to one embodiment of the present disclosure.

[0058] A common approach in communication system design is to ensure that UL transmission power does not change across symbols by performing power boosting (e.g., 3 dB power boosting for comb-2 muting symbols) on resource muting symbols. However, the issue becomes complex when the Phase Tracking Reference Signal (PT-RS) is assigned to muting symbols. This is because in the FR2 band, which is susceptible to phase noise, PT-RS signals are assigned at very narrow intervals along the time axis; if power boosting is performed only on the PT-RS assigned to muting symbols, the power will differ from that of the PT-RS assigned to normal symbols. Consequently, power mismatches between PT-RS symbols can lead to a decrease in the accuracy of phase noise estimation and correction.

[0059] Referring to FIG. 5, a method is presented to avoid the aforementioned problem by ensuring that the muting symbol and PT-RS do not overlap on the same symbol. The left figure of FIG. 5 shows an initial state where the muting symbol (shaded symbol 5) and PT-RS overlap. In this state, muting symbols 1, 2, and 3 are set to the ON state, and PT-RS and muting occur simultaneously on symbol 5, causing a power mismatch problem.

[0060] The right figure of Fig. 5 shows the result of disabling the muting symbol. By switching the muting of symbol 5, to which the PT-RS is assigned, to OFF, overlap between the PT-RS and the muting symbol is avoided. In this case, muting symbol 1 is set to OFF, muting symbol 2 is set to OFF, and muting symbol 3 is set to ON. This allows the PT-RS to maintain the same power level across all symbols, and ensures the accuracy of phase noise estimation and correction.

[0061] This method of disabling muting symbols can be implemented through dynamic signaling, and the base station can instruct the terminal not to perform muting on symbols assigned to PT-RS. Through this, both interference measurement performance and phase noise correction performance can be satisfied.

[0062] FIG. 6 illustrates a method for avoiding overlap with muting symbols through PT-RS deactivation according to one embodiment of the present disclosure.

[0063] As explained in Fig. 5, when muting symbols and PT-RS overlap on the same symbol, a problem may arise where the accuracy of phase noise estimation and correction is degraded due to power mismatch between PT-RS symbols. Fig. 6 presents a method to solve the overlap problem by disabling PT-RS instead of disabling muting symbols, using a different approach from Fig. 5.

[0064] Referring to Fig. 6, the left figure of Fig. 6 shows an initial state in which the muting symbol (shaded symbol 5) and PT-RS are superimposed. In this state, muting symbols 1, 2, and 3 are set to the ON state, and PT-RS and muting occur simultaneously on symbol 5, causing a power mismatch problem.

[0065] The right figure of Fig. 6 shows the result of disabling PT-RS. By switching the PT-RS assigned to muting symbol 5 to OFF, overlap between PT-RS and muting symbols is avoided. In this case, muting symbols 1, 2, and 3 all remain ON, and PT-RS is not transmitted from symbol 5. This allows for maximizing muting resources for interference measurement while maintaining power consistency among the remaining PT-RS symbols.

[0066] This PT-RS disable method prioritizes securing resources required for muting while sacrificing some phase noise correction capabilities. It can be effectively utilized in cases where phase noise estimation is possible even if the time axis interval of PT-RS is somewhat widened, or in cases where securing muting resources is more important. Depending on the system situation, the base station may select and apply an appropriate method between the method of Fig. 5 (muting symbol disable) and the method of Fig. 6 (PT-RS disable).

[0067] Method 1: Power boosting method excluding PT-RS within muting symbols

[0068] According to one embodiment of the present disclosure, a method is provided to maintain the same power level as the PT-RS in a normal symbol by not applying power boosting to the PT-RS resource element (RE) when performing power boosting on a muting symbol.

[0069] In one embodiment, 3 dB of power boosting is applied to the data RE in the comb-2 muting symbol, and the PT-RS can match the power of the PT-RS in the general symbol.

[0070] In another embodiment, instead of boosting the power of the data RE within the muting symbol by K dB (e.g., K=3), if the total power of the muting symbol is increased by K dB, the PT-RS RE power is not increased, so it is necessary to increase the power of the data RE by more than K dB. The power factor of the data RE to increase the total power of the muting symbol by K dB can be determined according to the following Equation 1.

[0071] [Mathematical Formula 1]

[0072]

[0074] Here,

[0075] · B: Number of data REs within the muting symbol

[0076] · C: Number of PT-RS REs in muting symbols

[0077] · K_linear =

[0078] Equation 1 is the power increase factor β that must be applied to the data RE to increase the total power of the muting symbol by K dB without changing the power of the PT-RS RE. data This is the formula for calculating it. Since the power of the PT-RS RE is kept constant, in order to increase the total symbol power by K dB, the power of the data RE must be increased by more than K dB.

[0079] A specific example of the above mathematical formula 1 is as follows.

[0080] Total number of REs = 24 (Number of muted REs = 12) B = 6 (Number of data REs) C = 6 (Number of PT-RS REs) K = 3 dB (Increases total symbol power by 3 dB)

[0081] In this case, It becomes 2, and if substituted into Formula 1:

[0082]

[0083] Therefore, β_data,dB = 10 × log10(3) Power boosting of 4.77 dB must be applied to the data RE.

[0084] Through this method, the total symbol power in muted symbols can be increased by the target value (K dB), while the PT-RS RE maintains the same power as the PT-RS of normal symbols. This ensures the accuracy of phase noise estimation and correction while minimizing the degradation of transmission performance caused by muting.

[0085] FIG. 7 illustrates a method for avoiding overlap between PT-RS and muting symbols through muting symbol rearrangement according to one embodiment of the present disclosure.

[0086] Figures 5 and 6 respectively present a method for disabling the muting symbol or PT-RS. Figure 7 presents a different approach to solving the overlap problem by relocating the muting symbol or PT-RS to an adjacent symbol.

[0087] Referring to Fig. 7, the left figure of Fig. 7 shows an initial state in which the muting symbol (shaded symbol 5) and PT-RS are superimposed. In this state, muting symbols 1, 2, and 3 are set to the ON state, and PT-RS and muting occur simultaneously on symbol 5, causing a power mismatch problem.

[0088] The right figure of Fig. 7 shows the result of relocating the muting symbols. By moving the muting of Symbol 5, to which PT-RS is assigned, to an adjacent symbol (Symbol 6), overlap between PT-RS and the muting symbols is avoided. After relocation, muting symbols 1, 2, and 3 remain ON, while the muting of Symbol 5 is OFF and, instead, the muting of Symbol 6 is ON. This allows PT-RS to maintain the same power level across all symbols while maintaining the total amount of muting resources.

[0089] The relocation of muting symbols can be implemented by moving to the immediately preceding or subsequent non-muting symbol, avoiding the symbol to which PT-RS is assigned. This method has the advantage of maintaining the total amount of muting resources required for interference measurement even if the temporal distribution of muting resources changes slightly. Additionally, the time axis interval of PT-RS can be maintained as is, so the phase noise estimation performance is not degraded.

[0090] The base station may instruct the terminal to a relocated muting symbol pattern through a semi-static configuration or dynamic signaling, and the terminal performs muting at a position adjusted accordingly.

[0091] FIG. 8 illustrates a method for avoiding overlap with muting symbols through PT-RS rearrangement according to one embodiment of the present disclosure.

[0092] Figure 7 presents a method for relocating muting symbols. Conversely, Figure 8 presents a method for solving the overlap problem by relocating PT-RS to adjacent symbols.

[0093] Referring to Fig. 8, the left figure of Fig. 8 shows an initial state in which the muting symbol (shaded symbol 5) and PT-RS are superimposed. In this state, muting symbols 1, 2, and 3 are set to the ON state, and PT-RS and muting occur simultaneously on symbol 5, causing a power mismatch problem.

[0094] The right figure of Fig. 8 shows the result of relocating the PT-RS. By moving the PT-RS assigned to muting symbol 5 to an adjacent symbol (symbol 6), overlap between the PT-RS and the muting symbol is avoided. After relocation, muting symbols 1, 2, and 3 all remain ON, and the PT-RS in symbol 5 is moved to symbol 6. This allows the PT-RS to maintain the same power level across all symbols without changing the location of the muting resource.

[0095] The reallocation of PT-RS can be implemented by moving the PT-RS that was scheduled to be assigned to the muting symbol to the immediately preceding or subsequent non-muting symbol. This method has the advantage of maintaining the original location of the muting resource. Even if the time axis interval of the PT-RS is partially adjusted, it may not significantly affect the phase noise estimation performance as long as the overall PT-RS density is maintained.

[0096] The base station can set a relocated PT-RS pattern for the terminal, and the terminal transmits or receives PT-RS at an adjusted location by avoiding muting symbols. This allows the time axis interval of the PT-RS to be maintained to some extent while preventing phase noise correction errors caused by power mismatch.

[0097] Through Method 2 (Figs. 5 and 6) and Method 3 (Figs. 7 and 8), the base station can selectively apply the most appropriate overlap avoidance method by considering system conditions, interference measurement priority, phase noise correction requirements, etc.

[0098] FIG. 9 is a flowchart illustrating the operation method of a first base station for measuring an interference signal in a wireless communication system according to one embodiment of the present disclosure.

[0099] Referring to FIG. 9, in step (910), the first base station exchanges information regarding radio resource configuration for measuring Cross-Link Interference (CLI) with the second base station. The first base station may operate as a Victim gNB (V-gNB) affected by interference, and the second base station may operate as an Aggressor gNB (A-gNB) generating an interference signal. The exchange of information regarding radio resource configuration may be performed via a wired or wireless link between the base stations. The first base station may receive CLI-RS radio resource configuration information from the second base station, or the first base station may determine CLI-RS radio resource configuration information and transmit it to the second base station, thereby requesting the second base station to transmit CLI-RS according to the corresponding CLI-RS radio resource configuration.

[0100] In step (920), the first base station sets a semi-static configuration of the muting resources to be applied to the terminal during uplink (UL) transmission. The first base station may set the semi-static configuration of the UL muting resources to the terminal through RRC (Radio Resource Control) signaling, MAC CE (Medium Access Control Element), or DCI (Downlink Control Information), etc. The terminal mutes the specified resources during UL transmission according to this semi-static configuration. The muting resources may be configured as a comb-2 pattern in each Physical Resource Block (PRB) to which a PUSCH (Physical Uplink Shared Channel) is allocated, and may be applied up to two symbols in the time domain.

[0101] In step (930), the first base station performs a measurement of the CLI reference signal (RS) received from the second base station in the muting resource. The UL muting resource may partially or entirely overlap with the CLI-RS resource transmitted by the second base station, but may not overlap. The first base station performs a CLI measurement based on the muting resource. If only a part of the muting resource overlaps with the CLI-RS, the entire muting resource may be used for the CLI measurement, or only the CLI-RS resource that overlaps with the muting resource may be used. The first base station can suppress the CLI between base stations by calculating the covariance matrix of the CLI between base stations using the measured CLI-RS and applying it to the MMSE-IRC (Minimum Mean Square Error and Interference Rejection Combiner) receiver.

[0102] In step (940), the first base station sets the number of muting symbols applied when calculating the Transport Block Size (TBS) to be fixed or semi-fixed. The first base station may apply a semi-fixed TBS calculation method. In one embodiment, the first base station may apply a worst-case TBS method that performs TBS calculation and rate matching by applying the maximum number of mutable symbols. In another embodiment, the first base station may perform TBS calculation and rate matching by applying the average expected number of muting symbols. Through this semi-fixed TBS calculation method, stable data transmission can be performed without the need to recalculate the TBS even if the muting symbols change dynamically.

[0103] FIG. 10 is a flowchart illustrating a method of operation of a terminal for measuring an interference signal in a wireless communication system according to one embodiment of the present disclosure.

[0104] Referring to FIG. 10, in step (1010), the terminal receives a semi-static configuration of muting resources to be applied during uplink (UL) transmission from the first base station. The first base station may be configured to mute some resources during the terminal's UL transmission for inter-base station CLI measurement. The terminal may receive the semi-static configuration of muting resources through Radio Resource Control (RRC) signaling, Medium Access Control Element (MAC CE), or Downlink Control Information (DCI), etc. The semi-static configuration of muting resources may include the location of the time-frequency resource to which muting is applied, a muting pattern (e.g., comb-2), and the maximum number of muting symbols.

[0105] In step (1020), the terminal mutes a designated resource during UL transmission according to the semi-fixed configuration. During PUSCH (Physical Uplink Shared Channel) transmission, the terminal does not transmit a signal from a specific resource element (RE) according to the muting pattern set by the base station. The muting resources can be configured as a comb-2 pattern in each physical resource block (PRB) and can be applied to up to two symbols in the time domain. The terminal can perform power boosting on the unmuted REs to ensure that the transmission power of all symbols remains constant. Muting is applied when the terminal is in RRC connection mode (RRC_CONNECTED mode), and muting is not applied to Msg A PUSCH and Msg 3 PUSCH.

[0106] In step (1030), the terminal transmits data based on the number of muting symbols set as fixed or semi-fixed when calculating the transmission block size (TBS). The terminal performs TBS calculation and rate matching by applying the number of fixed or semi-fixed muting symbols set by the base station. Through this, even if the number of muting symbols changes in each actual slot, the same TBS and rate matching structure can be used without the need to recalculate the TBS. The terminal can assume that the muting pattern does not overlap with the DMRS (Demodulation Reference Signal) or PT-RS (Phase Tracking Reference Signal) in the muting symbol, and power boosting in the muting symbol is applied per RE so that the PUSCH transmission power does not change across the symbol.

[0107] FIG. 11 illustrates a configuration diagram of a terminal in a wireless communication system according to various embodiments of the present disclosure. Terms such as ‘… unit’, ‘… unit’ used below refer to a unit that processes at least one function or operation, and this may be implemented in hardware or software, or a combination of hardware and software.

[0108] Referring to FIG. 11, the terminal may include a communication unit (1110), a storage unit (1120), and a control unit (1130).

[0109] The communication unit (1110) can perform functions for transmitting and receiving signals through a wireless channel. For example, the communication unit (1110) can perform conversion functions between a baseband signal and a bit sequence according to the physical layer specifications of the system. For example, when transmitting data, the communication unit (1110) can generate complex symbols by encoding and modulating the transmitted bit sequence. When receiving data, the communication unit (1110) can restore the received bit sequence by demodulating and decoding the baseband signal. Additionally, the communication unit (1110) can up-convert the baseband signal into an RF band signal and transmit it through an antenna, and down-convert the RF band signal received through the antenna into a baseband signal. For example, the communication unit (1110) may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, etc.

[0110] Additionally, the communication unit (1110) may include a plurality of transmission and reception paths. Furthermore, the communication unit (1110) may include at least one antenna array composed of a plurality of antenna elements. In terms of hardware, the communication unit (1110) may be composed of digital circuits and analog circuits (e.g., RFIC (radio frequency integrated circuit)). Here, the digital circuits and analog circuits may be implemented as a single package. Additionally, the communication unit (1110) may include a plurality of RF chains. Furthermore, the communication unit (1110) may perform beamforming.

[0111] The communication unit (1110) transmits and receives signals as described above. Accordingly, all or part of the communication unit (1110) may be referred to as a 'transmitter', a 'receiver', or a 'transceiver'. Additionally, in the following description, transmission and reception performed via a wireless channel may be used to include the processing performed by the communication unit (1110) as described above.

[0112] The storage unit (1120) can store data such as basic programs, application programs, and setting information for the operation of the terminal. The storage unit (1120) may be composed of volatile memory, non-volatile memory, or a combination of volatile memory and non-volatile memory. Additionally, the storage unit (1120) can provide the stored data upon a request from the control unit (1130).

[0113] The control unit (1130) can control the overall operations of the terminal. For example, the control unit (1130) can transmit and receive signals through the communication unit (1110). Additionally, the control unit (1130) can write and read data from the storage unit (1120). The control unit (1130) can perform the functions of the protocol stack required by the communication standard. To this end, the control unit (1130) may include at least one processor or microprocessor, or be part of a processor. Additionally, part of the communication unit (1110) and the control unit (1130) may be referred to as a communication processor (CP).

[0114] According to various embodiments, the control unit (1130) receives a semi-static configuration of a muting resource to be applied during uplink (UL) transmission from the first base station, mutes the resource specified during UL transmission according to the semi-static configuration, and can control the transmission of data based on the number of muting symbols set as fixed or semi-static applied when calculating the transmission block size (TBS). For example, the control unit (1130) can control the terminal to perform operations according to various embodiments described below.

[0115] FIG. 12 illustrates a configuration diagram of a base station in a wireless communication system according to various embodiments of the present disclosure. Terms such as ‘… unit’, ‘… unit’ used below refer to a unit that processes at least one function or operation, and this may be implemented in hardware or software, or a combination of hardware and software.

[0116] Referring to FIG. 12, the base station may include a wireless communication unit (1210), a backhaul communication unit (1220), a storage unit (1230), and a control unit (1240).

[0117] The wireless communication unit (1210) can transmit and receive wireless signals through a wireless channel. For example, the wireless communication unit (1210) can perform a conversion function between a baseband signal and a bit sequence according to the physical layer specifications of the system. In addition, when transmitting data, the wireless communication unit (1210) can generate complex symbols by encoding and modulating the transmitted bit sequence. When receiving data, the wireless communication unit (1210) can restore the received bit sequence by demodulating and decoding the baseband signal.

[0118] The wireless communication unit (1210) can up-convert a baseband signal into an RF (radio frequency) band signal and transmit it through an antenna, and down-convert an RF band signal received through an antenna into a baseband signal. To this end, the wireless communication unit (1210) may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC (digital to analog converter), and an ADC (analog to digital converter).

[0119] The wireless communication unit (1210) may include a plurality of transmission and reception paths, and the wireless communication unit (1210) may include at least one antenna array composed of a plurality of antenna elements.

[0120] In terms of hardware, the wireless communication unit (1210) may include a digital unit and an analog unit, and the analog unit may include a plurality of sub-units depending on operating power, operating frequency, etc. The digital unit may be implemented with at least one processor (e.g., a digital signal processor (DSP)).

[0121] The wireless communication unit (1210) can transmit and receive wireless signals as described above. Accordingly, all or part of the wireless communication unit (1210) may be referred to as a 'transmitter', 'receiver', or 'transceiver'. In addition, in the following description, transmission and reception performed through a wireless channel may include processing as described above being performed by the wireless communication unit (1210).

[0122] The backhaul communication unit (1220) can provide an interface for communicating with other nodes within the network. That is, the backhaul communication unit (1220) can convert a bit sequence transmitted from a base station to another node, e.g., another connection node, another base station, an upper node, and a core network, etc., into a physical signal, and can convert a physical signal received from another node into a bit sequence.

[0123] The storage unit (1230) can store data such as basic programs, application programs, and configuration information for the operation of the base station. The storage unit (1230) may be composed of volatile memory, non-volatile memory, or a combination of volatile memory and non-volatile memory. Additionally, the storage unit (1230) can provide the stored data upon request from the control unit (1240).

[0124] The control unit (1240) can control the overall operations of the base station. For example, the control unit (1240) can transmit and receive signals through the wireless communication unit (1210) or through the backhaul communication unit (1220). In addition, the control unit (1240) can write and read data to and from the storage unit (1230). Furthermore, the control unit (1240) can perform the functions of the protocol stack required by the communication standard.

[0125] To this end, the control unit (1240) may include at least one processor.

[0126] According to various embodiments of the present disclosure, the control unit (1240) may exchange information regarding the configuration of wireless resources for cross-link interference (CLI) measurement with the second base station, set a semi-fixed configuration of the muting resources to be applied when transmitting an uplink (UL) to the terminal, perform a measurement of the CLI reference signal (RS) received from the second base station in the muting resources, and control the number of muting symbols applied when calculating the transmission block size (TBS) to be fixed or semi-fixed. For example, the control unit (1240) may control the base station to perform operations according to various embodiments described below.

[0127] Methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0128] When implemented in software, a computer-readable storage medium may be provided for storing one or more programs (software modules). One or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. One or more programs include instructions that cause the electronic device to execute methods according to the embodiments described in the claims or specification of this disclosure.

[0129] Such programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), magnetic disc storage devices, compact disc-ROM (CD-ROM), digital versatile discs (DVDs), or other forms of optical storage devices, magnetic cassettes. Alternatively, they may be stored in memory composed of some or all of these. Additionally, each constituent memory may include multiple units.

[0130] Additionally, the program may be stored on an attachable storage device that can be accessed via a communication network such as the Internet, Intranet, LAN (local area network), WAN (wide area network), or SAN (storage area network), or a combination thereof. Such a storage device may be connected to a device performing an embodiment of the present disclosure through an external port. Additionally, a separate storage device on a communication network may be connected to a device performing an embodiment of the present disclosure.

[0131] In the specific embodiments of the present disclosure described above, the components included in the disclosure are expressed in a singular or plural form according to the specific embodiments presented. However, the singular or plural expression is selected to suit the situation presented for convenience of explanation, and the present disclosure is not limited to singular or plural components; even if a component is expressed in the plural form, it may be composed of a singular form, and even if a component is expressed in the singular form, it may be composed of a plural form.

[0132] Meanwhile, although specific embodiments have been described in the detailed description of the present disclosure, it is understood that various modifications are possible within the scope of the present disclosure. Therefore, the scope of the present disclosure should not be limited to the described embodiments, but should be defined by the claims set forth below as well as equivalents thereof.

Claims

Claim 1 A method of operation of a terminal for measuring interference signals in a wireless communication system, comprising: receiving a semi-static configuration of a muting resource to be applied during uplink (UL) transmission from a first base station; muting a resource specified during UL transmission according to the semi-static configuration; transmitting data based on the number of muting symbols set as fixed or semi-static applied when calculating a transmission block size (TBS); and, when a muting symbol and a phase tracking reference signal (PT-RS) overlap in the same symbol, relocating at least one of the muting symbol and the PT-RS to an adjacent symbol.

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