Electronic device and method for channel estimation in wireless communication system

Abstract

This electronic device comprises: at least one processor including a processing circuit; and a memory storing instructions and including one or more storage media, wherein the instructions, when executed individually or collectively by the at least one processor, may cause the electronic device to: acquire uplink RSs in an estimated RS symbol of an estimated slot from among a plurality of slots for uplink transmission; be mapped across at least two slots from among the plurality of slots for uplink transmission; acquire a first channel estimation result for a set of RS symbols other than the estimated RS symbol and a second channel estimation result for an RS symbol adjacent to the estimated RS symbol from among the RS symbols of the set of RS symbols; and acquire a channel estimation result for the estimated slot on the basis of the result of comparing a first estimation index using the first channel estimation result and the uplink RSs with a second estimation index using the second channel estimation result and the uplink RSs.

Description

Electronic device and method for channel estimation in wireless communication systems

[0001] The present disclosure relates to a wireless communication system, and more particularly, to an electronic device and method for channel estimation in a wireless communication system.

[0002] In wireless communication systems, terminals transmitting or receiving wireless signals can move. This movement of the terminals causes changes in the wireless channel. Communication equipment providing the network can estimate channel changes caused by frequency dispersion, spread, and fluctuations due to the terminal's movement.

[0003] The above information may be provided as background art to aid in understanding the present disclosure. No claim or determination is made as to whether any of the above is applicable as prior art related to the present disclosure.

[0004] In embodiments of the present disclosure, an electronic device is provided. The electronic device may include at least one processor including a processing circuit. The electronic device may include a memory storing instructions and including one or more storage media. The instructions, when individually or collectively executed by the at least one processor, may cause the electronic device to obtain uplink reference signal (RS) symbols in an estimated RS (reference signal) symbol of an estimation slot among a plurality of slots for uplink transmission, obtain a first channel estimation result for a set of RS symbols that are mapped across at least two slots among the plurality of slots for uplink transmission and are different from the estimated RS symbol, obtain a second channel estimation result for an RS symbol adjacent to the estimated RS symbol among RS symbols of the set of RS symbols, and obtain a channel estimation result for the estimation slot based on a comparison result between a first estimation index using the first channel estimation result and the uplink RSs and a second estimation index using the second channel estimation result and the uplink RSs.

[0005] In embodiments of the present disclosure, a method performed by an electronic device is provided. The method may include: obtaining uplink reference signal (RS) symbols from an estimated RS (reference signal) symbol of an estimation slot among a plurality of slots for uplink transmission; obtaining a first channel estimation result for a set of RS symbols that are mapped across at least two slots among the plurality of slots for uplink transmission and are different from the estimated RS symbol; obtaining a second channel estimation result for an RS symbol adjacent to the estimated RS symbol among RS symbols of the set of RS symbols; and obtaining a channel estimation result for the estimation slot based on a comparison result between a first estimation index using the first channel estimation result and the uplink RSs and a second estimation index using the second channel estimation result and the uplink RSs.

[0006] In embodiments of the present disclosure, a non-transitory computer-readable storage medium is provided. The non-transitory computer-readable storage medium may include instructions that, when executed by a processor, cause an electronic device to perform operations including: obtaining uplink reference signal (RS) symbols from an estimated RS symbol of an estimation slot among a plurality of slots for uplink transmission; obtaining a first channel estimation result for a set of RS symbols that are mapped across at least two slots among the plurality of slots for uplink transmission and are different from the estimated RS symbol; obtaining a second channel estimation result for an RS symbol adjacent to the estimated RS symbol among RS symbols of the set of RS symbols; and obtaining a channel estimation result for the estimation slot based on a comparison result between a first estimation index using the first channel estimation result and the uplink RSs and a second estimation index using the second channel estimation result and the uplink RSs.

[0007] In embodiments of the present disclosure, an electronic device is provided. The electronic device may include at least one processor including a processing circuit. The at least one processor may be configured to obtain uplink reference signal (RS) symbols in an estimated RS symbol of an estimation slot among a plurality of slots for uplink transmission, obtain a first channel estimation result for a set of RS symbols that are mapped across at least two slots among the plurality of slots for uplink transmission and are different from the estimated RS symbol, obtain a second channel estimation result for an RS symbol adjacent to the estimated RS symbol among RS symbols of the set of RS symbols, and obtain a channel estimation result for the estimation slot based on a comparison result between a first estimation index using the first channel estimation result and the uplink RSs and a second estimation index using the second channel estimation result and the uplink RSs.

[0008] The above and other aspects, features and advantages of specific embodiments of the present disclosure will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:

[0009] Figure 1 shows a wireless communication system.

[0010] Figure 2 shows network entities according to distributed deployment.

[0011] Figure 3 shows an example of a resource structure in the time domain and frequency domain.

[0012] Figure 4 shows an example of function split of network entities.

[0013] Figure 5 shows examples of channels in a communication standard.

[0014] Figures 6a, 6b, and 6c show examples of reference signals (RSs) within a slot.

[0015] Figures 7a and 7b illustrate examples of slot aggregation.

[0016] Figure 7c shows an example of channel estimation performance according to Doppler frequency.

[0017] Figures 8a and 8b show examples of slots in slot aggregation.

[0018] Figures 9a, 9b, 9c, and 9d illustrate examples of comparisons between channel estimation using at least two slots and channel estimation using one slot.

[0019] Figure 10 shows an example of a complex plane for the equalized value of a received signal.

[0020] Figure 11 shows the operation flow of an electronic device for channel estimation.

[0021] Figures 12a and 12b are drawings for explaining the relationship between the comparison index and the Doppler frequency.

[0022] Figure 13 shows examples of channel estimation performance according to Doppler frequency.

[0023] Figure 14a illustrates the functional configuration of an electronic device.

[0024] Figure 14b illustrates the functional configuration of a wireless communication device.

[0025] The terms used in this disclosure are used only to describe specific embodiments and may not be intended to limit the scope of other embodiments. The singular expression may include plural expressions unless the context clearly indicates otherwise. Terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by those of ordinary skill in the art described in this disclosure. Terms defined in general dictionaries among the terms used in this disclosure may be interpreted as having the same or similar meaning in the context of the relevant technology, and shall not be interpreted in an idealized or overly formal sense unless explicitly defined in this disclosure. In some cases, even if a term is defined in this disclosure, it cannot be interpreted to exclude embodiments of the present disclosure.

[0026] The various embodiments of the present disclosure described below illustrate a hardware-based approach as an example. However, since the various embodiments of the present disclosure include techniques utilizing both hardware and software, the various embodiments of the present disclosure do not exclude a software-based approach.

[0027] In the following description, terms referring to signals (e.g., signal, information, message, signaling), terms referring to data types (e.g., list, set, subset), terms for operational states (e.g., step, operation, procedure), terms referring to data (e.g., packet, user stream, information, bit, symbol, codeword), terms referring to resources (e.g., symbol, slot, subframe, radio frame, subcarrier, resource element (RE), resource block (RB), bandwidth part (BWP), occasion), terms referring to channels, terms referring to network entities, terms referring to components of devices, etc. are examples for convenience of description. Therefore, the present disclosure is not limited to the terms described below, and other terms having equivalent technical meanings may be used. In addition, the terms '...bu', '...gi', '...mul', '...che', etc. used below may mean at least one shape structure or a unit that processes a function.

[0028] In addition, in the present disclosure, expressions such as "more than" or "less than" may be used to determine whether a specific condition is satisfied or fulfilled, but this is merely a description for expressing an example and does not exclude descriptions such as "more than" or "less than." A condition described as "more than" may be replaced with "more than," a condition described as "less than" may be replaced with "less than," and a condition described as "more than and less than" may be replaced with "more than and less than." In addition, hereinafter, "A" to "B" mean at least one of elements from A (including A) to B (including B). hereinafter, "C" and / or "D" mean at least one of "C" or "D," that is, including {"C", "D", "C" and "D"}.

[0029] Although the present disclosure describes various embodiments using terms used in some communication standards (e.g., 3rd Generation Partnership Project (3GPP), European Telecommunications Standards Institute (ETSI), extensible radio access network (xRAN), open-radio access network (O-RAN), etc.), these are merely examples for explanation. The various embodiments of the present disclosure can be easily modified and applied to other communication systems.

[0030] In the present disclosure, the communication quality may be, for example, at least one of RSRP (reference signal received power), BRSRP (beam reference signal received power), RSRQ (reference signal received quality), RSSI (received signal strength indicator), SINR (signal to interference and noise ratio), CINR (carrier to interference and noise ratio), SNR (signal to noise ratio), EVM (error vector magnitude), BER (bit error rate), and BLER (block error rate). In addition to the examples described above, other terms having equivalent technical meanings or other metrics indicating channel quality may be used. Hereinafter, in the present disclosure, high communication quality means a case where a communication quality value related to a signal size is large or a communication quality value related to an error rate is small. A higher communication quality may mean that a smooth wireless communication environment is guaranteed. In addition, an optimal beam may mean a beam having the highest communication quality among beams.

[0031] Figure 1 shows a wireless communication system.

[0032] Referring to FIG. 1, FIG. 1 illustrates a base station (110) and a terminal (120) as some of the nodes utilizing a wireless channel in a wireless communication system. Although FIG. 1 illustrates only one base station, the wireless communication system may further include other base stations identical or similar to the base station (110).

[0033] The base station (110) is a network infrastructure that provides wireless access to terminals (120). The base station (110) has coverage defined based on the distance at which a signal can be transmitted. In addition to the base station, the base station (110) includes an 'access point (AP)', a 'RAN (radio access network) node', an 'eNodeB (eNB)', and a '5G node (5 th The term "network node" may be referred to as "next generation node (gNB)", "wireless point", "transmission / reception point (TRP)", "communication node", "wireless communication device", "wireless communication equipment", "network node", "network entity", or other terms having equivalent technical meaning.

[0034] The terminal (120) is a device used by a user and communicates with the base station (110) via a wireless channel. The link from the base station (110) to the terminal (120) is referred to as a downlink (DL), and the link from the terminal (120) to the base station (110) is referred to as an uplink (UL). In addition, although not shown in FIG. 1, the terminal (120) and another terminal may communicate with each other via a wireless channel. In this case, the link between the terminal (120) and another terminal (device-to-device link, D2D) is referred to as a sidelink, and the sidelink may be used interchangeably with the PC5 interface. In some other embodiments, the terminal (120) may be operated without the involvement of a user. In one embodiment, the terminal (120) is a device that performs machine type communication (MTC) and may not be carried by the user. Additionally, according to one embodiment, the terminal (120) may be an NB (narrowband)-IoT (internet of things) device.

[0035] The terminal (120) may be referred to as a terminal, or other terms such as 'user equipment (UE),' 'customer premises equipment (CPE),' 'mobile station,' 'subscriber station,' 'remote terminal,' 'wireless terminal,' 'electronic device,' or 'user device,' or other terms having equivalent technical meanings.

[0036] The base station (110) can perform beamforming with the terminal (120). The base station (110) and the terminal (120) can transmit and receive wireless signals in a relatively low frequency band (e.g., FR 1 (frequency range 1) of NR). In addition, the base station (110) and the terminal (120) can transmit and receive wireless signals in a relatively high frequency band (e.g., FR 2 (or, FR 2-1, FR 2-2, FR 2-3), FR 3 of NR), millimeter wave (mmWave) band (e.g., 26 GHz, 28 GHz, 30 GHz, 38 GHz, 60 GHz)). To improve channel gain, the base station (110) and the terminal (120) can perform beamforming. Here, the beamforming can include transmission beamforming and reception beamforming. The base station (110) and the terminal (120) can impart directionality to the transmitted or received signal. To this end, the base station (110) and the terminal (120) can select serving beams through a beam search or beam management procedure. After the serving beams are selected, subsequent communication can be performed through resources that have a QCL relationship with the resource that transmitted the serving beams.

[0037] If large-scale characteristics of a channel carrying a symbol on a first antenna port can be inferred from a channel carrying a symbol on a second antenna port, the first antenna port and the second antenna port can be evaluated to have a QCL relationship. For example, the large-scale characteristics may include at least one of delay spread, Doppler spread, Doppler shift, average gain, average delay, and a spatial receiver parameter.

[0038] Although both the base station (110) and the terminal (120) are described as performing beamforming in FIG. 1, the embodiments of the present disclosure are not necessarily limited thereto. In some embodiments, the terminal may or may not perform beamforming. Furthermore, the base station may or may not perform beamforming. That is, either only one of the base station and the terminal may perform beamforming, or neither the base station nor the terminal may perform beamforming.

[0039] In the present disclosure, a beam refers to a spatial flow of a signal in a wireless channel, and is formed by one or more antennas (or antenna elements), and this forming process may be referred to as beamforming. Beamforming may include at least one of analog beamforming and digital beamforming (e.g., precoding). Reference signals transmitted based on beamforming may include, for example, a demodulation-reference signal (DMRS), a channel state information-reference signal (CSI-RS), a synchronization signal / physical broadcast channel (SS / PBCH), and a sounding reference signal (SRS). In addition, as a configuration for each reference signal, an IE such as a CSI-RS resource or an SRS-resource may be used, and this configuration may include information associated with the beam. Information associated with a beam may mean whether the configuration (e.g., a CSI-RS resource) uses the same spatial domain filter as another configuration (e.g., another CSI-RS resource within the same CSI-RS resource set) or a different spatial domain filter, or whether it is quasi-co-located (QCL) with a reference signal, and if so, what type it is (e.g., QCL type A, B, C, D).

[0040] FIG. 2 illustrates network entities according to a distributed arrangement. For example, the network entities may include a digital unit (DU) and a radio unit (RU) (220) (or a massive multiple input multiple output (MMU) unit). For example, the network entities may be connected via a fronthaul. Unlike the backhaul between a base station and a core network, the fronthaul refers to entities (e.g., DU (210), RU (220)) between a wireless LAN and a base station. Although FIG. 2 illustrates an example of a fronthaul structure between a DU (210) and one RU (220), this is merely for convenience of explanation and the present disclosure is not limited thereto. In other words, embodiments of the present disclosure may also be applied to a fronthaul structure between one DU and multiple RUs. For example, embodiments of the present disclosure may be applied to a fronthaul structure between one DU and two RUs. Additionally, the embodiments of the present disclosure can also be applied to a fronthaul structure between one DU and three RUs.

[0041] Referring to FIG. 2, the base station (110) may include a DU (210) and a RU (220). The front hole (215) between the DU (210) and the RU (220) is F xIt can be operated through an interface. For the operation of the fronthaul (215), for example, an interface such as eCPRI (enhanced common public radio interface) and ROE (radio over ethernet) can be used. Depending on the implementation example, in addition to the DU (digital unit), the DU (210) may be referred to as a baseband unit (BBU), a digital BBU, a baseband digital unit, a digital processing unit, a digital processing circuit, a baseband processing circuit, a baseband processing unit, and / or equivalent technical terms therefor. Depending on the implementation example, in addition to the RU (radio unit), the RU (220) may be referred to as a remote unit, a radio demote head (RRH), a radio processing circuit, a radio processing unit, an antenna integrated radio, an air radio device, an air scale communication device, a radio device, a radio communication device, and / or equivalent technical terms therefor. Also, according to the implementation example, the network entity connected to the DU (210) in the present disclosure is described as the RU (210), but it is of course possible for a massive multiple input multiple output (MMU) unit to be connected to the DU (210) and used instead of the RU (210).

[0042] As communication technology advances, mobile data traffic increases, significantly increasing the bandwidth requirements for the fronthaul between the digital unit and the wireless unit. In a deployment such as a centralized / cloud radio access network (C-RAN), the DU performs functions for the packet data convergence protocol (PDCP), radio link control (RLC), media access control (MAC), and physical (PHY) layer, while the RU can be implemented to perform functions for the PHY layer in addition to the radio frequency (RF) function. The DU (210) can be responsible for upper layer functions of the wireless network.

[0043] For example, DU (210) can perform functions of MAC layer and part of PHY layer. Here, part of PHY layer means functions performed at a higher level among the functions of PHY layer, and may include, for example, channel encoding (or channel decoding), scrambling (or descrambling), modulation (or demodulation), layer mapping (or layer demapping). According to an embodiment, if DU (210) complies with O-RAN standard, it may be referred to as O-DU (O-RAN DU). DU (210) may be replaced and expressed as a first network entity for a base station (e.g., gNB) in embodiments of the present disclosure, if necessary. RU (220) may be in charge of lower layer functions of a wireless network. For example, RU (220) may perform part of PHY layer and RF functions. Here, a part of the PHY layer refers to functions of the PHY layer that are performed at a relatively lower level than the DU (210), and may include, for example, iFFT transform (or FFT transform), CP insertion (CP removal), and digital beamforming. The RU (220) may be referred to as an 'access unit (AU)', an 'access point (AP)', a 'transmission / reception point (TRP)', a 'remote radio head (RRH)', a 'radio unit (RU)', or other terms having an equivalent technical meaning thereto. According to an embodiment, when the RU (220) complies with the O-RAN standard, it may be referred to as an O-RU (O-RAN RU). The RU (220) may be expressed by being replaced with a second network entity for a base station (e.g., gNB) in embodiments of the present disclosure, as needed.

[0044] In FIG. 2, the base station (110) is described as including a DU (210) and a RU (220), but the embodiments of the present disclosure are not limited thereto. The base station according to the embodiments may be implemented in a distributed deployment according to a centralized unit (CU) configured to perform functions of upper layers of an access network (e.g., packet data convergence protocol (PDCP), radio resource control (RRC)) and a distributed unit (DU) configured to perform functions of lower layers. For example, the digital unit (DU) (210) may be implemented by being separated into the CU and the DU. Between a core (e.g., 5GC (5G core) or NGC (next generation core)) network and a radio network (RAN), the base station may be implemented in a structure in which the CU, DU, and RU are arranged in that order. The interface between the CU and the distributed unit (DU) may be referred to as an F1 interface.

[0045] A centralized unit (CU) can be connected to one or more DUs and can be responsible for functions at a higher layer than the DU. For example, the CU can be responsible for functions at the RRC (radio resource control) and PDCP (packet data convergence protocol) layers, while the DU and RU can be responsible for functions at lower layers. The DU can perform some functions (high PHY) of the RLC (radio link control), MAC (media access control), and PHY (physical) layers, while the RU can be responsible for the remaining functions (low PHY) of the PHY layer. In addition, for example, a digital unit (DU) can be included in a distributed unit (DU) depending on the implementation of a distributed deployment of the base station. Hereinafter, unless otherwise defined, the operations of DU (digital unit) and RU are described, but various embodiments of the present disclosure can be applied to both a base station arrangement including a CU and an arrangement in which a DU is directly connected to a core network (i.e., a base station in which the CU and DU are integrated into a single entity (e.g., an NG-RAN node)).

[0046] Figure 3 illustrates examples of resource structures in the time and frequency domains. Figure 3 illustrates the basic structure of the time-frequency domain, a radio resource domain where data or control channels are transmitted in the downlink or uplink.

[0047] Referring to Figure 3, the horizontal axis represents the time domain and the vertical axis represents the frequency domain. The minimum transmission unit in the time domain is an OFDM symbol, N symbOFDM symbols (302) are grouped to form one slot (306). The length of a subframe is defined as 1.0 ms, and the length of a radio frame (314) is defined as 10 ms. The minimum transmission unit in the frequency domain is a subcarrier, and the carrier bandwidth constituting the resource grid is N BW It consists of a number of subcarriers (304).

[0048] The basic unit of resources in the time-frequency domain is a resource element (RE) (312), which can be represented by an OFDM symbol index and a subcarrier index. A resource block may include multiple resource elements. In the LTE system, a resource block (RB) (or physical resource block (PRB)) is N in the time domain. symb N consecutive OFDM symbols and frequency domain SC RB are defined as N consecutive subcarriers. In the NR system, a resource block (RB) (308) is defined as N in the frequency domain. SC RB can be defined as a series of consecutive subcarriers (310). One RB (308) is N in the frequency axis. SC RB It contains REs (312). In general, the minimum transmission unit of data is RB and the number of subcarriers is N. SC RB=12. The frequency domain may include common resource blocks (CRBs). Physical resource blocks (PRBs) may be defined in the bandwidth part (BWP) of the frequency domain. The CRB and PRB numbers may be determined based on the subcarrier spacing. The data rate may increase in proportion to the number of RBs scheduled to the terminal.

[0049] In the NR system, in the case of a frequency division duplex (FDD) system that operates the downlink and uplink by frequency division, the downlink transmission bandwidth and the uplink transmission bandwidth may be different. The channel bandwidth represents the radio frequency (RF) bandwidth corresponding to the system transmission bandwidth. [Table 1] shows part of the correspondence between the system transmission bandwidth, subcarrier spacing (SCS), and channel bandwidth defined in the NR system in a frequency band lower than x GHz (e.g., frequency range (FR) 1 (310 MHz to 7125 MHz)). And [Table 2] shows part of the correspondence between the transmission bandwidth, subcarrier spacing, and channel bandwidth defined in the NR system in a frequency band higher than y GHz (e.g., FR 2 (24250 MHz - 52600 MHz) or FR 2-2 (52600 MHz to 71000 MHz)). For example, an NR system with a 100 MHz channel bandwidth and a 30 kHz subcarrier spacing has a transmission bandwidth of 273 RBs. In [Table 1] and [Table 2], N / A may indicate a bandwidth-subcarrier combination not supported by the NR system.

[0050] Channel bandwidth [MHz] SCS 5 10 20 50 80 100 Transmission bandwidth configuration N RB15kHz2552106207N / AN / A30kHz11245113321727360kHzN / A112465107135

[0051] Channel bandwidth [MHz] SCS50100200400 Transmission bandwidth configuration N RB 60kHz66132264N / A120kHz3266132264

[0052] Figure 4 shows an example of function splitting of network entities. As wireless communication technology advances (e.g., 5G (5 th With the introduction of 5G communication systems (or NR (new radio) communication systems), the frequency bands used have increased further. As the cell radius of base stations has become significantly smaller, the number of RUs required for installation has also increased further. Furthermore, in 5G communication systems, the amount of data transmitted has increased by a factor of up to ten, significantly increasing the transmission capacity of wired networks transmitted to the fronthaul. Due to the factors described above, the installation cost of wired networks in 5G communication systems may increase significantly. Therefore, in order to lower the transmission capacity of wired networks and reduce the installation cost of wired networks, 'function split' can be utilized to transfer some of the functions of the modem of the DU to the RU, thereby lowering the transmission capacity of the fronthaul. Although described as RU below, the function split described below can be equally applied not only to RUs but also to the relationship between the MMU and the DU.

[0053] To reduce the burden on the DU, the role of the RU, which is traditionally solely responsible for RF functions, can be expanded to include some physical layer functions. As the RU performs higher-layer functions, its throughput increases, which can increase transmission bandwidth in the fronthaul while reducing latency requirements due to response processing. However, as the RU performs higher-layer functions, virtualization gains decrease, and the RU's size, weight, and cost increase. Considering the trade-offs between the advantages and disadvantages described above, implementing an optimal functional separation is required.

[0054] Referring to Figure 4, the functional separation in the physical layer below the MAC layer is illustrated. For the downlink (DL) that transmits a signal to a terminal through a wireless network, the base station can sequentially perform channel encoding / scrambling, modulation, layer mapping, antenna mapping, RE mapping, digital beamforming (e.g., precoding), iFFT transform / CP insertion, and RF transform. For the uplink (UL) that receives a signal from a terminal through a wireless network, the base station can sequentially perform RF transform, FFT transform / CP removal, digital beamforming (pre-combining), RE demapping, channel estimation, layer demapping, demodulation, and decoding / descrambling. The separation of uplink and downlink functions can be defined in various types depending on the needs of vendors, discussions in standards, etc., according to the above-mentioned trade-offs.

[0055] In the first functional separation (405), the RU performs the RF function, and the DU performs the PHY function. The first functional separation is one in which the PHY function is not substantially implemented in the RU, and may be referred to as Option 8, for example. In the second functional separation (410), the RU performs iFFT conversion / CP insertion in the DL and FFT conversion / CP removal in the UL of the PHY function, and the DU performs the remaining PHY functions. As an example, the second functional separation (410) may be referred to as Option 7-1. In the third functional separation (420a), the RU performs iFFT conversion / CP insertion in the DL and FFT conversion / CP removal and digital beamforming in the UL of the PHY function, and the DU performs the remaining PHY functions. As an example, the third functional separation (420a) may be referred to as Option 7-2x Category A. In the fourth functional separation (420b), the RU performs up to digital beamforming in both the DL and UL, and the DU performs upper PHY functions after the digital beamforming. For example, the fourth functional separation (420b) may be referred to as Option 7-2x Category B. In the fifth functional separation (425), the RU performs up to RE mapping (or RE demapping) in both the DL and UL, and the DU performs upper PHY functions after RE mapping (or RE demapping). For example, the fifth functional separation (425) may be referred to as Option 7-2. In the sixth functional separation (430), the RU performs up to modulation (or demodulation) in both the DL and UL, and the DU performs upper PHY functions after modulation (or demodulation). For example, the sixth functional separation (430) may be referred to as Option 7-3. In the seventh functional separation (440), the RU performs encoding / scrambling (or decoding / descrambling) in both the DL and UL, and the DU performs subsequent upper PHY functions up to modulation (or demodulation). For example, the seventh functional separation (440) may be referred to as Option 6.

[0056] In one embodiment, when a large amount of signal processing is expected, such as in the FR 1 MMU, functional separation at a relatively high layer (e.g., the fourth functional separation (420b)) may be required to reduce fronthaul capacity. In addition, functional separation at too high a layer (e.g., the sixth functional separation (430)) may complicate the control interface and cause a burden on the implementation of the RU due to the inclusion of a large number of PHY processing blocks within the RU. Therefore, appropriate functional separation may be required depending on the arrangement and implementation method of the DU and the RU.

[0057] In one embodiment, if the precoding of data received from the DU cannot be processed (i.e., if the precoding capability of the RU is limited), the third functional separation (420a) or a lower functional separation (e.g., the second functional separation (410)) may be applied. Conversely, if the DU has the capability to process the precoding of data received from the DU, the fourth functional separation (420b) or a higher functional separation (e.g., the sixth functional separation (430)) may be applied.

[0058] The O-RAN standard distinguishes the types of O-RUs depending on whether the precoding function is located at the interface of the O-DU or the O-RU interface. For example, the RU may perform operations according to the functional separation of the third functional separation (420a) (which may be referred to as category A (CAT-A)) or the fourth functional separation (420b) (which may be referred to as category B (CAT-B)) for performing beamforming processing. In other words, an O-RU that does not perform precoding (i.e., has low complexity) may be referred to as a CAT-A O-RU. An O-RU that performs precoding may be referred to as a CAT-B O-RU. In addition, for example, channel estimation may be performed in the O-RU instead of the O-DU. To improve uplink performance, the O-RU may also operate according to the sixth functional separation (430) (Option 7-3).

[0059] Hereinafter, the term "upper-PHY" refers to physical layer processing performed in the DU of the fronthaul interface. For example, the upper-PHY may include FEC encoding / decoding, scrambling, and modulation / demodulation. Hereinafter, the term "lower-PHY" refers to physical layer processing performed in the RU of the fronthaul interface. For example, the lower-PHY may include FFT / iFFT, digital beamforming, and PRACH (physical random access channel) extraction and filtering. However, the above-described criteria do not exclude embodiments through other functional separations. The functional configuration, signaling, or operation of FIGS. 5 to 14b described below may be applied not only to the third functional separation (420a), the fourth functional separation (420b), but also to other functional separations (e.g., the sixth functional separation (430). In addition, for example, channel estimation may be performed in the O-RU instead of the O-DU. To improve uplink performance, the O-RU may also operate according to the sixth functional separation (430) (Option 7-3).

[0060] Figure 5 shows examples of channels in a communication standard.

[0061] Referring to FIG. 5, the channels may include a physical channel (510), a transport channel (520), and a logical channel (530) according to layers defined in a communication standard. The physical channel (510) may provide functions (e.g., channel coding, HARQ processing, modulation, multi-antenna processing, resource mapping) necessary for generating physical signals in the physical layer. In the physical layer, the physical signals are modulated using OFDM and may be transmitted in a wireless environment through time-frequency resources (e.g., resources of the resource grid of FIG. 3).

[0062] In downlink transmission, a physical channel (510) may include at least one of a physical broadcast channel (PBCH), a physical downlink shared channel (PDSCH), or a physical downlink control channel (PDCCH). The PDCCH may be used to carry downlink control information (DCI). Generally, downlink data may refer to symbols transmitted through the PDSCH, and a downlink control signal may refer to symbols transmitted through the PDCCH. In addition, in the downlink, in addition to the channels illustrated in FIG. 4, a synchronization signal (e.g., a primary synchronization signal (PSS), a secondary synchronization signal (SSS)) and an SS / PBCH block including a broadcast signal (e.g., a PBCH)) may be transmitted for synchronization. In addition, in the downlink, a channel state information-reference signal (CSI-RS) for obtaining measurement or channel information, a demodulation reference signal (DMRS) for channel estimation and demodulation, and a phase tracking reference signal (PTRS) may be transmitted in the downlink.

[0063] In uplink transmission, a physical channel (510) may include at least one of a physical uplink shared channel (PUSCH), a physical uplink control channel (PUCCH), or a physical random access channel (PRACH). The PUSCH or PUCCH may be used to carry uplink control information (UCI). Generally, uplink data refers to symbols transmitted through the PUSCH, and the uplink control signal may mean symbols corresponding to the UCI. For example, the UCI may include at least one of a scheduling request (SR), a hybrid automatic request (HARQ)-acknowledge (ACK) bit(s), or channel state information (CSI). In addition, in the uplink, in addition to the channels illustrated in FIG. 4, DMRS and PTRS for channel estimation and demodulation may be transmitted in the downlink for channel estimation.

[0064] A transmission channel (520) connects a physical layer and a medium access channel (MAC) layer located at an upper level of the physical layer, and can be classified according to how data is transmitted via a wireless interface. In a downlink, a transmission channel (520) may include at least one of a paging channel (PCH) for paging, a broadcast channel (BCH) for broadcasting system information, or a downlink shared channel (DL-SCH) for transmitting downlink data. In an uplink, a transmission channel (520) may include at least one of a random access channel (RACH) for transmitting a random access preamble or an uplink shared channel (UL-SCH) for transmitting downlink data.

[0065] The logical channel (530) is located above the transport channel and is mapped to the transport channel (520). The logical channel (530) can be divided into a control channel for transmitting control region information and a traffic channel for transmitting user region information. The control channel of the logical channel (530) can include at least one of a paging control channel (PCCH), a broadcast control channel (BCCH), a common control channel (CCCH), or a dedicated control channel (DCCH). The traffic channel of the logical channel (530) can include a dedicated traffic channel (DTCH).

[0066] In describing embodiments of the present disclosure, "data" may refer to sequences other than reference signals. For example, "data" acquired by a receiver in uplink communication may refer to signals transmitted via the PUSCH. However, the PUSCH is merely exemplary, and it is understood that embodiments of the present disclosure may also be applied to other channels requiring channel estimation (e.g., PDSCH, PBCH, PDCCH, PUCCH).

[0067] Figures 6a, 6b, and 6c illustrate examples of reference signals (RSs) within a slot. The reference signals can be used for channel estimation. For example, a demodulation reference signal (DMRS) can be used for coherent demodulation with data (e.g., PDSCH, PUSCH). Hereinafter, channel estimation using DMRS is exemplified, but the embodiments of the present disclosure described below can also be applied to channel estimation using SRSs. Hereinafter, uplink transmission of an NR communication system is described as an example to explain the channel estimation of the present disclosure and operations using DMRS for channel estimation. However, the embodiments of the present disclosure are not limited to the uplink of an NR communication system. It goes without saying that the embodiments of the present disclosure can also be applied to the downlink or other communication systems.

[0068] Referring to FIG. 6A, an electronic device (e.g., base station (110), DU (210)) can receive uplink signals from a terminal (e.g., terminal (120)) on a slot (e.g., slot (306)). Hereinafter, an operation between the base station (110) and the terminal (120) is exemplified. The terminal (120) can transmit uplink signals to the base station (110) on the slot. The slot may include 14 symbols (e.g., symbol #0 (600), symbol #1 (601), symbol #2 (602), symbol #3 (603), symbol #4 (604), symbol #5 (605), symbol #6 (606), symbol #7 (607), symbol #8 (608), symbol #9 (609), symbol #10 (610), symbol #11 (611), symbol #12 (612), and symbol #13 (613)). At least some of the 14 symbols may be used to carry DMRS sequences. The symbols carrying the DMRS sequences may be referred to as RS symbols. Among the symbols in the slot, symbols other than the RS symbol are regions to which uplink data can be mapped and may be referred to as data symbols.

[0069] The received uplink signals may include data (hereinafter, “received data”) received on an uplink channel (e.g., PUSCH). The received data may be transmitted in data symbols in the time domain. In addition, the received uplink signals may include reference signals (hereinafter, “reception reference signals”) (e.g., DMRS) for channel estimation and coherent demodulation of the data symbols. The reception reference signals may be transmitted in RS symbols in the time domain. For example, the RS symbols may include symbol #2 (602) and symbol #11 (611). The base station (110) (e.g., DU (210)) may estimate a channel between the base station (110) (e.g., RU (220)) and the terminal (120) through the reception reference signals. The base station (110) may obtain information about the channel experienced by the reception reference signals. For example, the base station (110) can obtain information about the channel experienced by the received data through the relationship between the positions where the RS symbols of the reception reference signals are mapped and the positions where the data symbols of the received data are mapped. For example, the base station (110) can obtain information about the channel experienced by the received data by performing interpolation (or extrapolation) in the frequency domain or interpolation (or extrapolation) in the time domain based on the information about the channel experienced by the reception reference signals. The base station (110) can estimate the channel in each resource element in the time-frequency resource by using uplink reference signals (e.g., DMRS, SRS).

[0070] Although FIG. 6A illustrates an example in which channel estimation is performed using two RS symbols (e.g., symbol #2 (602) and symbol #11 (611)) within a single slot, embodiments of the present disclosure are not limited thereto. The mapping of RS symbols used for channel estimation may vary depending on the DMRS configuration. For example, more than two RS symbols may be mapped within a single slot, or only one RS symbol may be mapped within a single slot.

[0071] Referring to FIG. 6b, the slot may include 14 symbols (e.g., symbol #0 (600), symbol #1 (601), symbol #2 (602), symbol #3 (603), symbol #4 (604), symbol #5 (605), symbol #6 (606), symbol #7 (607), symbol #8 (608), symbol #9 (609), symbol #10 (610), symbol #11 (611), symbol #12 (612), and symbol #13 (613)). The RS symbols may include symbol #2 (602), symbol #3 (603), symbol #10 (610), and symbol #11 (611) among the 14 symbols. In this way, the positions and number of RS symbols to which uplink RSs are mapped within the slot may vary.

[0072] An electronic device (e.g., a base station (110), a DU (210)) can transmit an RS configuration to a terminal (e.g., a terminal (120)) via upper layer signaling (e.g., an RRC signaling). The following is an example of an operation between a base station (110) and a terminal (120). The terminal (120) can transmit uplink signals based on parameters in the RS configuration received from the base station (110). For example, the RS configuration can include a DMRS configuration for a PUSCH. The above RS configuration may include at least one of information on a DMRS configuration type (e.g., frequency resources corresponding to a corresponding antenna port may vary depending on whether the DMRS configuration type is type 1 or type 2), information on a DMRS mapping type (e.g., positions of RS symbols may vary depending on whether the PUSCH mapping type is Type A (indexing from the start symbol of a slot, e.g., symbol #0 (600))) or Type B (indexing from an area to which a PUSCH is allocated within a slot)), information on positions of symbols to which DMRS is mapped (e.g., the number and positions of RS symbols mapped within a slot may be determined according to a DMRS additional position IE), and / or information on a length of consecutive symbols to which DMRS is mapped (e.g., whether the length of consecutively mapped symbols is 1 (i.e., a single symbol) or 2 (i.e., a double symbol)).

[0073] The terminal (120) can transmit uplink signals based on the above parameters via a plurality of antennas. For example, each antenna can correspond to an antenna port for uplink DMRSs (e.g., one of DMRS antenna ports 1000, 1001, 1002, 1003, 1004, 1005, 1006, and 1007). The terminal (120) can map an RS sequence to a resource location (e.g., RE) of an RS symbol specified according to the antenna. The RS sequence can be dependent on the location of the mapping resource and / or the antenna port. For example, the terminal (120) can transmit DMRSs for PUSCH via four antennas. The four antennas can correspond to antenna port 1000, antenna port 1001, antenna port 1002, and antenna port 1003, respectively. Referring to FIG. 6c, the first grid (651) represents RE mapping of DMRSs transmitted through an antenna corresponding to antenna port 1000. The number of DMRS symbols in a slot is 2, and DMRS sequences can be mapped to REs of the 3rd symbol and the 12th symbol in the slot. The second grid (652) represents RE mapping of DMRSs transmitted through an antenna corresponding to antenna port 1001. The third grid (653) represents RE mapping of DMRSs transmitted through an antenna corresponding to antenna port 1002. The fourth grid (654) represents RE mapping of DMRSs transmitted through an antenna corresponding to antenna port 1003.

[0074] Figures 7a and 7b illustrate examples of slot aggregation. Slot aggregation refers to a technique for allocating data (e.g., PUSCH, PDSCH) to consecutive slots to improve decoding performance in weak electric fields in a communication system (e.g., LTE, NR). Hereinafter, the present disclosure exemplifies PUSCH transmission across multiple slots as an example of slot aggregation, but it is to be understood that embodiments of the present disclosure can be applied to downlink as well as uplink. Hereinafter, to explain the relationship between slot aggregation and RS symbols, a situation in which two RS symbols are mapped to one slot is described.

[0075] Referring to Fig. 7a, the horizontal axis represents time and the vertical axis represents frequency. An electronic device (e.g., a base station (110), a DU (210)) may sequentially allocate slots within the same frequency domain (e.g., the same RB) for slot aggregation of PUSCH. For example, the electronic device may transmit a PUSCH configuration with an aggregation factor set to 2 to a terminal (120). The terminal (e.g., the terminal (120)) may transmit uplink signals in a first slot (710) and a second slot (720). The first slot (710) may include a first RS symbol (711) and a second RS symbol (712). The second slot (720) may include a first RS symbol (721) and a second RS symbol (722). Thereafter, when performing retransmission, the terminal (120) can transmit uplink signals corresponding to the retransmission in the third slot (730) and the fourth slot (740). The third slot (730) can include a first RS symbol (731) and a second RS symbol (732). The fourth slot (740) can include a first RS symbol (741) and a second RS symbol (742). The terminal (120) can transmit uplink signals corresponding to the retransmission in the same frequency domain as the initial transmission (e.g., PUSCH transmission in the first slot (710) and the second slot (720).

[0076] Referring to FIG. 7B, the horizontal axis represents time and the vertical axis represents frequency. An electronic device (e.g., a base station (110), a DU (210)) may sequentially allocate slots within the same frequency domain (e.g., the same RB) for slot aggregation of PUSCH. For example, the electronic device may transmit a PUSCH configuration with an aggregation factor set to 2 to a terminal (120). The terminal (e.g., the terminal (120)) may transmit uplink signals in a first slot (710) and a second slot (720). The first slot (710) may include a first RS symbol (711) and a second RS symbol (712). The second slot (720) may include a first RS symbol (721) and a second RS symbol (722). Thereafter, when retransmitting, the terminal (120) may change the frequency domain. The terminal (120) may transmit uplink signals corresponding to the retransmission in a different frequency domain than the initial transmission (e.g., PUSCH transmission in the first slot (710) and the second slot (720). The terminal (120) may transmit the uplink signals corresponding to the retransmission in the third slot (730) and the fourth slot (740). The third slot (730) may include a first RS symbol (731) and a second RS symbol (732). The fourth slot (740) may include a first RS symbol (741) and a second RS symbol (742).

[0077] The frequency domains corresponding to multiple slots of slot aggregation may be the same or different frequency domains depending on the network configuration. To achieve frequency diversity, slots of slot aggregation may be allocated across different frequency domains. On the other hand, if slots of slot aggregation are allocated across the same frequency domain, a base station receiving uplink signals can obtain improved channel estimation results through reference signals transmitted across the slots. Hereinafter, the present disclosure describes a channel estimation technique for data transmitted across slots according to slot aggregation within the same frequency domain to achieve high channel estimation performance in a weak electric field.

[0078] As mentioned above, estimating the channel by considering all RS symbols transmitted across multiple slots within the same frequency range can provide performance improvements in weak electromagnetic fields. However, in environments with high Doppler frequencies (e.g., high-speed mobile environments), signal distortion may occur as channel estimation results accumulate across slots, which may actually reduce the accuracy of the channel estimation results. Therefore, in environments with low Doppler frequencies (e.g., low mobile speeds), the accumulated channel estimation results from slots assigned to the same frequency range should be utilized as much as possible. In environments with high Doppler frequencies (e.g., high mobile speeds), the instantaneous channel estimation values ​​within a single slot should be utilized.

[0079] Figure 7c shows an example of channel estimation performance according to Doppler frequency.

[0080] Referring to FIG. 7c, a graph (780) represents communication quality according to Doppler frequency. The horizontal axis of the graph (780) represents the Doppler frequency (unit: Hz (hertz)), and the vertical axis represents the SNR (unit: dB (decibel)) required to meet a BLER of 10% or less. The first line (781) represents the SNR when using the channel estimation results of eight slots, and the second line (782) represents the SNR when using the channel estimation result of one slot. For example, at a Doppler frequency of less than about 10 Hz, the first line (781) represents a higher communication SNR than the second line (782). At a Doppler frequency of about 100 Hz or more, the second line (782) represents that a higher SNR is required than the second line (781). In other words, as the Doppler frequency increases, utilizing channel estimation results for a single slot requires relatively less SNR than utilizing channel estimation results for multiple slots. This relatively lower SNR requirement may indicate higher channel estimation performance.

[0081] Hereinafter, the present disclosure proposes a technique for adaptively determining which method is more advantageous for performing channel estimation in a situation where signals are repeatedly transmitted across a plurality of slots (e.g., slot aggregation, repetition of signal transmissions for terminals such as MTC terminals or NB-IoT terminals, a situation where slots are allocated consecutively), and performing channel estimation according to the determined method, taking into account the matters mentioned in FIGS. 7A to 7C. For example, an electronic device (e.g., a base station (110), a DU (210), a terminal (120)) can adaptively determine a channel estimation method by comparing an estimation index according to a channel estimation result for at least two slots among a plurality of slots for repeated transmission (e.g., a plurality of slots configured by slot aggregation) with an estimation index according to a channel estimation result for a single slot, and demodulate data symbols according to the determined channel estimation method.

[0082] Figures 8a and 8b illustrate examples of slots in slot aggregation. Repeated transmission of PUSCHs can be performed on these slots.

[0083] Referring to FIG. 8A, an electronic device (e.g., a base station (110), a DU (210)) may transmit DCI (801) to a terminal (e.g., a terminal (120)) on a slot (810). The DCI (801) may indicate uplink resource allocation. The DCI (801) may indicate resource allocation for uplink data (e.g., a PUSCH) in the time domain and resource allocation for uplink data in the frequency domain. For example, the DCI (801) may be transmitted according to DCI format 0_0, DCI format 0_1, or DCI format 0_2. The electronic device may transmit a PUSCH configuration including an aggregation factor to the terminal (120) via RRC signaling. Repetitive PUSCH transmissions may be allocated to the terminal (120) via the DCI (801). PUSCH transmissions may be repeatedly allocated in a number according to the aggregation factor. For example, the aggregation factor may be set to '2'. The terminal (120) may identify scheduled uplink resources from the DCI (801). The terminal (120) may identify a first slot (710) and a second slot (720). The terminal (120) may repeatedly transmit uplink data (e.g., PUSCH) to the electronic device over the first slot (710) and the second slot (720). The first slot (710) may include a first RS symbol (711) and a second RS symbol (712). The first slot (710) may include a PUSCH region (715). Uplink data may be mapped to the PUSCH region (715). The second slot (720) may include a first RS symbol (721) and a second RS symbol (722). The second slot (720) may include a PUSCH region (725). Uplink data may be mapped to the PUSCH region (725).As a non-limiting example, uplink data in the PUSCH region (725) may correspond to the same transport block (TB) as the uplink data in the PUSCH region (715) and may have a different redundancy version (RV). For example, uplink data in the PUSCH region (715) may correspond to RV0. Uplink data in the PUSCH region (725) may correspond to RV2.

[0084] Referring to FIG. 8b, an electronic device (e.g., base station (110), DU (210)) may transmit DCI (801) to a terminal (e.g., terminal (120)) on a slot (810). The DCI (801) may indicate uplink resource allocation. Unlike FIG. 8a, the electronic device may transmit a PUSCH configuration including an aggregation factor set to '4' to the terminal (120) via RRC signaling. The terminal (120) may identify a plurality of slots according to slot aggregation. The plurality of slots may be consecutive in the time domain. As the aggregation factor is set to '4', the terminal (120) may identify four slots. For example, the terminal (120) may identify a first slot (710), a second slot (720), a third slot (830), and a fourth slot (840). The terminal (120) may repeatedly transmit uplink data to the electronic device across the plurality of slots. A first slot (710) may include a first RS symbol (711) and a second RS symbol (712). The first slot (710) may include a PUSCH region (715) corresponding to uplink data. A second slot (720) may include a first RS symbol (721) and a second RS symbol (722). The second slot (720) may include a PUSCH region (725) corresponding to uplink data. A third slot (830) may include a first RS symbol (831) and a second RS symbol (832). The third slot (830) may include a PUSCH region (835) corresponding to uplink data. A fourth slot (840) may include a first RS symbol (841) and a second RS symbol (842). The fourth slot (840) may include a PUSCH region (845) corresponding to uplink data. As a non-limiting example, uplink data in each PUSCH region may correspond to the same TB and have different RVs.For example, uplink data in the PUSCH region (715) may correspond to RV0. Uplink data in the PUSCH region (725) may correspond to RV2. Uplink data in the PUSCH region (835) may correspond to RV3. Uplink data in the PUSCH region (845) may correspond to RV1.

[0085] Figures 9a, 9b, 9c, and 9d illustrate examples of comparison between channel estimation using at least two slots (hereinafter, referred to as the first method) and channel estimation using one slot (hereinafter, referred to as the second method). An electronic device (e.g., a base station (110), a DU (210)) can receive RSs. The electronic device can estimate the channel experienced by the RSs and demodulate data signals using the estimation result. When estimating the channel experienced by the RSs, the electronic device can adaptively select one of various methods. For example, the electronic device can adaptively select one of the first method (901) that uses channel estimation results accumulated over multiple slots and the second method (902) that uses the channel estimation result in one slot. The purpose of comparing the first method (901) and the second method (902) may be to compensate for the influence of Doppler distortion that may occur during channel estimation.

[0086] Referring to FIG. 9A, an electronic device (e.g., a base station (110), a DU (210)) may receive uplink data on a plurality of slots according to slot aggregation. The plurality of slots may include a first slot (710) and a second slot (720). RSs for demodulating the uplink data may be mapped onto RS symbols. The first slot (710) may include a first RS symbol (711) and a second RS symbol (712). The second slot (720) may include a first RS symbol (721) and a second RS symbol (722).

[0087] The electronic device can receive uplink RSs in a second RS symbol (722). For example, the uplink RSs may be DMRSs for PUSCH. The electronic device can perform channel estimation for the second slot (720) through the uplink RSs. The electronic device can obtain a channel estimation result for the uplink RSs in order to demodulate uplink data in the second slot (720). In order to determine a channel scheme for the uplink RSs, the electronic device can use both an estimation index according to a first scheme (901) (hereinafter, referred to as a first estimation index) and an estimation index according to a second scheme (902) (hereinafter, referred to as a second estimation index). Hereinafter, a symbol to which the uplink RSs are mapped (e.g., a second RS symbol (722)) may be referred to as an estimation RS symbol, a target RS symbol, and / or equivalent technical terms thereto in terms of being a target for current channel estimation.

[0088] In the first method (901), the electronic device may determine a set (910) of RS symbols other than an estimated RS symbol (e.g., the second symbol (722)) from among RS symbols mapped to the first slot (710) and the second slot (720). The set (910) of RS symbols may include a first RS symbol (711) of the first slot (710), a second RS symbol (712) of the first slot (710), and a first RS symbol (721) of the second slot (720). The electronic device may obtain a channel estimation result (hereinafter, referred to as a first channel estimation result) for the set (910) of RS symbols. The electronic device may obtain one first channel estimation result by using all of the channel estimation results of the RS symbols of the set (910) of RS symbols. The channel estimation results of the RS symbols of the set (910) of RS symbols may be accumulated. For example, the electronic device may obtain the first channel estimation result through an operation (e.g., an average, an effective value) on channel estimation results of RS symbols of the set (910) of RS symbols. The RS symbol used for the first channel estimation result (e.g., an RS symbol of the set (910) of RS symbols) may be referred to as an accumulated RS symbol in terms of providing an accumulated channel estimation result.

[0089] In the second method (902), the electronic device may determine an RS symbol sample (960) to know an instantaneous channel state. The electronic device may determine, as the RS symbol sample (960), a first RS symbol (721) adjacent to an estimated RS symbol (e.g., a second RS symbol (722)) among RS symbols of the set of RS symbols (910). The electronic device may obtain a channel estimation result (hereinafter, referred to as a second channel estimation result) for a second RS symbol (722) corresponding to the RS symbol sample (960). The RS symbol used for the second channel estimation result (e.g., the RS symbol corresponding to the RS symbol sample (960)) may be referred to as a sample RS symbol in that it is selected from among symbols different from the estimated RS symbol, or may be referred to as an adjacent RS symbol in that it is a symbol adjacent to the estimated RS symbol.

[0090] Referring to FIG. 9b, an example of using accumulated RS symbols different from those in FIG. 9a in the first method (901) is described. For example, the estimated RS symbol may be the first symbol (721). The electronic device may determine a set (920) of RS symbols different from the estimated RS symbol (e.g., the first symbol (721)) among the RS symbols mapped to the first slot (710) and the second slot (720). The set (920) of RS symbols may include the first RS symbol (711) of the first slot (710), the second RS symbol (712) of the first slot (710), and the second RS symbol (722) of the second slot (720). The electronic device may obtain a channel estimation result (hereinafter, referred to as a first channel estimation result) for the set (920) of RS symbols. The electronic device may obtain a first channel estimation result by using all channel estimation results of RS symbols of the set of RS symbols (920). The channel estimation results of RS symbols of the set of RS symbols (920) may be accumulated. In the second method (902), the electronic device may determine an RS symbol sample (970) to know an instantaneous channel state. The electronic device may determine, as the RS symbol sample (970), a second RS symbol (722) adjacent to an estimated RS symbol (e.g., a first RS symbol (721)) among the RS symbols of the set of RS symbols (910). According to one embodiment, the electronic device may determine the sample (970) from among symbols included in an estimation slot of the estimated RS symbol. In other words, a symbol for obtaining the second channel estimation result may be included in the same slot as the estimated RS symbol. The electronic device can obtain a channel estimation result (hereinafter, the second channel estimation result) for a second RS symbol (722) corresponding to an RS symbol sample (970).

[0091] Referring to FIG. 9c, an example of using accumulated RS symbols different from those in FIGS. 9a and 9b in the first method (901) is described. For example, the estimated RS symbol may be the second symbol (842) of the fourth slot (840). The electronic device may determine a set (930) of RS symbols different from the estimated RS symbol (e.g., the second symbol (842)) among the RS symbols mapped to the first slot (710), the second slot (720), the third slot (830), and the fourth slot (840). The set (930) of RS symbols may include a first RS symbol (711) of a first slot (710), a second RS symbol (712) of the first slot (710), a first RS symbol (721) of a second slot (720), a second RS symbol (722) of a second slot (720), a first RS symbol (831) of a third slot (830), a second RS symbol (832) of a third slot (830), and a first RS symbol (841) of a fourth slot (840). The electronic device may obtain a channel estimation result (hereinafter, referred to as a first channel estimation result) for the set (930) of RS symbols. The electronic device may obtain one first channel estimation result by using all of the channel estimation results of the RS symbols of the set (930) of RS symbols. The channel estimation results of the RS symbols of the set (930) of RS symbols may be accumulated. In the second method (902), the electronic device can determine an RS symbol sample (980) to know an instantaneous channel state. The electronic device can determine, as the RS symbol sample (980), a first RS symbol (841) adjacent to an estimated RS symbol (e.g., a second RS symbol (842)) among the RS symbols of the set of RS symbols (930). The electronic device can obtain a channel estimation result (hereinafter, a second channel estimation result) for the first RS symbol (841) corresponding to the RS symbol sample (980).

[0092] Referring to FIG. 9d, an example of using accumulated RS symbols different from those in FIGS. 9a, 9b, and 9c in the first method (901) is described. For example, the estimated RS symbol may be the second symbol (842) of the fourth slot (840). The electronic device may determine a set (940) of RS symbols different from the estimated RS symbol (e.g., the second symbol (842)) among the RS symbols mapped to the second slot (720), the third slot (830), and the fourth slot (840). Even in a situation where four slots are configured for slot aggregation, slots for obtaining the first channel estimation result may be identified by the electronic device instead of using all slots. The set of RS symbols (940) may include a first RS symbol (721) of a second slot (720), a second RS symbol (722) of a second slot (720), a first RS symbol (831) of a third slot (830), a second RS symbol (832) of a third slot (830), and a first RS symbol (841) of a fourth slot (840). The electronic device may obtain a channel estimation result (hereinafter, referred to as a first channel estimation result) for the set of RS symbols (940). The electronic device may obtain one first channel estimation result by using all of the channel estimation results of the RS symbols of the set of RS symbols (940). The channel estimation results of the RS symbols of the set of RS symbols (940) may be accumulated. In the second method (902), the electronic device may determine an RS symbol sample (990) to know an instantaneous channel state. The electronic device may determine, as an RS symbol sample (990), a first RS symbol (841) adjacent to an estimated RS symbol (e.g., a second RS symbol (842)) among the RS symbols of the set of RS symbols (940). The electronic device may obtain a channel estimation result (hereinafter, a second channel estimation result) for the first RS symbol (841) corresponding to the RS symbol sample (990).

[0093] Comparing FIGS. 9A, 9B, 9C, and 9D, even if the electronic device performs channel estimation in the same manner (e.g., manner (901)), the set of RS symbols to be targeted can be configured differently. According to one embodiment, the electronic device can determine a set of RS symbols including all previous RS symbols based on a current estimated RS symbol among a plurality of slots for which uplink transmission is set. For example, the electronic device can obtain a first channel estimation result using channel estimation results for all slots prior to the estimation slot of the current estimated RS symbol. According to another embodiment, the electronic device can determine a set of RS symbols including RS symbols in slots according to a fixed number. For example, the electronic device can include RS symbols in two previous slots based on the current estimation target estimated RS symbol in the set of RS symbols (e.g., set of RS symbols (920)). For example, the electronic device may include RS symbols within a total of two slots, including the estimated slot of the estimated RS symbol that is currently the target of estimation, in the set of RS symbols (e.g., the set of RS symbols (910)). For example, the electronic device may include RS symbols within a total of three slots, including the estimated slot of the estimated RS symbol that is currently the target of estimation, in the set of RS symbols (e.g., the set of RS symbols (940)). According to another embodiment, the electronic device may determine the set of RS symbols based on communication quality (e.g., RSRP, CSI, BLER). The electronic device may determine the number of accumulated slots based on the communication quality. The electronic device may identify slots equal to the number of determined accumulated slots. The electronic device may determine the set of RS symbols including RS symbols within the identified slots.

[0094]

[0095] The electronic device can obtain uplink RSs received through at least one antenna. As described with reference to FIG. 7c, the sequences of uplink RSs may depend on the location of a transmitted resource and the antenna port. The electronic device can obtain uplink RSs corresponding to a corresponding antenna port from the estimated RS symbol. For example, the electronic device can obtain the uplink RSs through an antenna of the electronic device (e.g., corresponding to one of DMRS antenna ports 1000, 1001, 1002, 1003, 1004, 1005, 1006, 1007). For example, the electronic device can obtain the uplink RSs corresponding to a specific antenna port (e.g., a DMRS antenna port) through a separate device (e.g., an RU, an MMU) connected to the electronic device.

[0096] The uplink RSs received from the above estimated RS symbols can be expressed by the following mathematical formula.

[0097]

[0098]

[0099] [Mathematical formula 1] can be expressed as a formula for each antenna as follows.

[0100]

[0101]

[0102] Since the electronic device receives a previously known sequence (e.g., a DMRS sequence) from an estimated RS symbol, it can perform decorrelation on the received signal. The electronic device can obtain an equalization value as a result of the decorrelation. For example, the electronic device can determine an equalization value (hereinafter, referred to as a first equalization value) using the first channel estimation result, the sequence, and the signal received from the estimated RS symbol. For example, the first equalization value can be determined based on the following mathematical equation.

[0103]

[0104]

[0105]

[0106]

[0107] If we assume ideal channel estimation results, the ideal equalization values ​​are as follows.

[0108]

[0109]

[0110] If there is no noise and the channel estimation is accurate, the ideal equalization value can be a real value. On the other hand, if the channel estimation is inaccurate, the equalization value can be a complex value including a real part and an imaginary part. In other words, the closer the channel estimation result is to the actual channel value, the larger the size of the real part and the smaller the size of the imaginary part. The complex plane can be used to describe how close the channel estimation result is to the actual channel value.

[0111] Figure 10 shows an example of a complex plane for the equalized value of a received signal.

[0112] Referring to FIG. 10, the horizontal axis of the complex plane (1000) represents the real axis, and the vertical axis of the complex plane (1000) represents the imaginary axis. As described above, the smaller the noise and the more accurate the channel estimation result, the closer the electronic device can obtain an equalization value to the real axis. The less accurate the channel estimation result, the farther away it can be from the real axis. That is, since the electronic device knows in advance the sequence and modulation method (e.g., QPSK) transmitted from the terminal, the electronic device can evaluate the first equalization value and the second equalization value. According to one embodiment, if the phase (1007) is between about (+) 45 degrees and about (-) 45 degrees with respect to the real axis, the electronic device can determine that the corresponding equalization value is valid. The validity of the equalization value may indicate that the channel estimation was performed accurately to a certain level or higher.

[0113] The electronic device can determine a first estimation index using the first channel estimation result according to the first method (901). The first estimation index can indicate how close the first channel estimation result is to an actual channel. The electronic device can determine, for each of the subcarriers to which the estimated RS symbol is mapped, whether a first equalization value is located within a valid region (1005). For example, the electronic device can identify, as the first estimation index, the number of REs in which the first equalization value is located within the valid region (1005). In the same manner, the electronic device can determine a second estimation index using the second channel estimation result according to the second method (902). The second estimation index can indicate how close the second channel estimation result is to an actual channel. The electronic device can determine, for each of the subcarriers to which the estimated RS symbol is mapped, whether a second equalization value is located within a valid region (1005). For example, the electronic device may identify the number of REs in which the second equalization value is located within the valid area (1005) as the second estimated indicator. For example, the electronic device may determine the estimated indicator according to each of the first method (901) and the second method (902) based on the following mathematical equation.

[0114]

[0115]

[0116]

[0117]

[0118] The electronic device can determine an estimation index by performing the above-described judgment for all REs assigned to the estimated RS symbol. The electronic device can count REs located within a valid area (1005). The first estimation index indicates the number of REs whose equalization values ​​are located within the valid area (1005) when the first channel estimation result according to the first method (901) is used. The second estimation index indicates the number of REs whose equalization values ​​are located within the valid area (1005) when the second channel estimation result according to the second method (902) is used.

[0119] The electronic device can determine, by comparing the first estimation index and the second estimation index, whether it is advantageous to perform channel estimation of the current slot using channel estimation results accumulated over multiple slots, or whether it is advantageous to perform channel estimation only for the current slot. For example, the electronic device can determine a comparison index according to the following mathematical formula.

[0120]

[0121]

[0122]

[0123] Meanwhile, the comparison index of mathematical expression 8 is an example, and it is of course possible to perform division or other comparison operations in addition to subtraction. Depending on the type of the comparison index, the threshold value may vary. Similarly, the expression of mathematical expression 9 is an example operation, and any method of comparing two estimation indices can be understood as an embodiment of the present disclosure. According to one embodiment, the electronic device may determine a channel estimation method of an estimation slot including an estimation RS symbol based on a comparison result between the first estimation index and the second estimation index. The electronic device may identify one of a first method (901) that uses at least two slots among a plurality of slots according to slot aggregation and a second method (902) that uses a single slot.

[0124] Figure 11 shows the operation flow of an electronic device (e.g., base station (110), DU (210)) for channel estimation.

[0125] Referring to FIG. 11, in operation 1101, the electronic device may acquire uplink RSs in an estimated RS symbol among a plurality of slots for uplink transmission. The electronic device may receive uplink signals from another electronic device (e.g., terminal 120). The other electronic device may be configured to perform repeated transmission. The repeated transmission may be performed across multiple slots within the same frequency domain. For example, the other electronic device may transmit uplink signals across a plurality of slots according to slot aggregation or a separate number of repetitions setting according to a network configuration. The other electronic device may transmit uplink data within each slot. Each slot may include uplink RSs for demodulating uplink data. The electronic device may perform channel estimation on a slot-by-slot basis. The electronic device may perform channel estimation on RSs within a slot, and then perform channel estimation on uplink data within the slot using the results of the channel estimation for the RSs. The electronic device can demodulate the uplink data using the result of channel estimation for the uplink data. The slot where such channel estimation is performed may be referred to as an estimation slot. The estimation RS symbol represents an RS symbol in the estimation slot where channel estimation for the current uplink RS is performed. The electronic device can receive the uplink RSs. The electronic device can determine the RS sequence that the other electronic device actually transmitted based on the resource location of the estimation RS symbol.

[0126] In operation (1103), the electronic device may obtain a first channel estimation result for a set of RS symbols (e.g., set of RS symbols (910), set of RS symbols (910), set of RS symbols (930), set of RS symbols (940)) that is mapped across at least two slots among a plurality of slots for uplink transmission and is different from an estimated RS symbol. The electronic device may perform channel estimation according to a first method (e.g., first method (901)) that uses accumulated channel estimation results for a plurality of slots. The electronic device may obtain the first channel estimation result by using all of the channel estimation results of the RS symbols of the set of RS symbols. For example, the first channel estimation result may be an average of estimated values ​​accumulated across a plurality of slots.

[0127] In operation (1105), the electronic device can obtain a second channel estimation result for an RS symbol (e.g., RS symbol sample (960), RS symbol sample (970), RS symbol sample (980), and RS symbol sample (990)) adjacent to the estimated RS symbol among symbols of the set of RS symbols. The electronic device can perform channel estimation according to a second method (e.g., second method (902)) that utilizes a channel estimation result in a single slot (e.g., a channel estimation result in an instantaneous symbol). For example, the electronic device can utilize a previously obtained channel estimation result for the RS symbol. For example, the electronic device can perform channel estimation for the RS symbol by comparing a signal received in an RS symbol adjacent to the estimated RS symbol with a predefined sequence.

[0128] In operation (1107), the electronic device can obtain a channel estimation result for an estimation slot based on a comparison result between a first estimation index using a first channel estimation result and uplink RSs and a second estimation index using a second channel estimation result and uplink RSs.

[0129] The electronic device may determine a first equalization value using the first channel estimation result of operation (1103), the uplink RSs, and the uplink sequence in the estimated RS symbol. For example, the electronic device may determine the first equalization value in each of the subcarriers corresponding to the estimated RS symbol in the time domain. For example, to determine the first equalization value, descriptions of [Mathematical Formula 3] may be referred to. The electronic device may determine a first estimation index using the first equalization value. The first estimation index may indicate how close the first channel estimation result is to an actual channel (i.e., the accuracy of the channel estimation). For example, to determine the first estimation index, the electronic device may determine, for each of the subcarriers, how much the first equalization value differs from an ideal value. For example, the electronic device may determine, for each subcarrier, whether a phase (e.g., phase (1007)) of the first equalization value is within a threshold range. The phase may represent the angle between the real and imaginary parts of the equalization value in the complex plane. The better the channel estimation is performed, the closer the equalization value can be to a real number. The electronic device may determine the number of subcarriers in which the first equalization value is located within a critical range from the real axis. For the first estimation index, the descriptions of [Mathematical Formula 6] may be referred to.

[0130] The electronic device may determine a second equalization value using the second channel estimation result of operation (1103) and the uplink RSs and the uplink sequence in the estimated RS symbol. For example, the electronic device may determine the second equalization value in each of the subcarriers corresponding to the estimated RS symbol in the time domain. For example, to determine the first equalization value, descriptions regarding [Mathematical Formula 4] may be referenced. A second estimation index may be determined using the second equalization value. The second estimation index may indicate how close the first channel estimation result is to an actual channel (i.e., accuracy of channel estimation). For example, to determine the second estimation index, the electronic device may determine, for each of the subcarriers, how much the second equalization value differs from an ideal value. The electronic device may determine, for each subcarrier, whether a phase (e.g., phase (1007)) of the second equalization value is within a threshold range. The electronic device can determine the number of subcarriers in which the second equalization value is located within a critical range from the real axis. For the first estimated index, the descriptions of [Mathematical Formula 6] can be referred to.

[0131] The electronic device can compare a first estimation index and a second estimation index. Based on the comparison result between the first estimation index and the second estimation index, the electronic device can select which estimation method is more advantageous for the current channel state among the first method (901) and the second method (902). In an RS symbol, the electronic device can identify a channel estimation method (e.g., the first method (901), the second method (902)) suitable for the RS symbol by comparing the first estimation index and the second estimation index. For example, when the first estimation index is higher than the second estimation index, the electronic device can identify a method (e.g., the first method (901)) that uses channel estimation results accumulated over at least two or more slots. When the first estimation index is lower than the second estimation index, the electronic device can identify a method (e.g., the second method (902)) that uses a channel estimation result for a single slot (e.g., an RS symbol sample). Meanwhile, an offset may be set for a specific estimated indicator. For example, a comparison may be performed using a threshold value (e.g., "TH"), as in [Equations 8] and [Equations 9]. If the threshold value is positive, the equations may be understood to have set an offset favorable to the first estimated indicator.

[0132] The electronic device may perform channel estimation for an estimation slot according to an identified method. The electronic device may utilize channel estimation results of a plurality of slots including the estimation slot, or may utilize only the channel estimation results of the estimation slot.

[0133] For example, the electronic device can obtain a channel estimation result by using a signal received in the estimated RS symbol and a sequence in the estimated RS symbol. If the first method (901) is identified, the electronic device can perform channel estimation on data symbols in the estimation slot by using the obtained channel estimation result and estimation results of previous slots. If the second method (902) is identified, the electronic device can perform channel estimation on data symbols in the estimation slot by using only the channel estimation result for the RS symbol of the estimation slot (including the obtained channel estimation result).

[0134] In FIG. 11, the RS symbol sample is described as a symbol adjacent to the estimated RS symbol, but embodiments of the present disclosure are not limited thereto. According to one non-limiting embodiment, the electronic device may determine the RS symbol sample as an RS symbol at a predefined location within a slot (e.g., the first RS symbol within the slot, or the first RS symbol among RS symbols located within the area to which the PUSCH is mapped).

[0135] Figures 12a and 12b are drawings for explaining the relationship between the comparison index and the Doppler frequency.

[0136] Referring to Fig. 12a, a graph (1200) represents a PDF (probability density function) according to a comparison index. The horizontal axis of the graph (1200) represents the comparison index. The vertical axis of the graph (1200) represents the PDF. The comparison index may be a result of comparing a first estimated index obtained through a first channel estimation result with a second estimated index obtained through a second channel estimation result. For example, the comparison index may be a value obtained by subtracting the first estimated index obtained through the first channel estimation result from the second estimated index obtained through the second channel estimation result. As an example, [Mathematical Formula 8] may be referred to for the comparison index.

[0137] The first line (1201) represents the PDF according to the comparison index when the Doppler frequency is 10 Hz. The second line (1202) represents the PDF according to the comparison index when the Doppler frequency is 100 Hz. The third line (1203) represents the PDF according to the comparison index when the Doppler frequency is 200 Hz. Comparing the first line (1201), the second line (1202), and the third line (1203), it can be confirmed that the comparison index relatively increases as the Doppler frequency increases. It can be confirmed that the larger the comparison index, the more advantageous the second estimation index is over the first estimation index. In other words, in an environment with a high Doppler frequency (e.g., a communication environment with a high-speed mobile terminal), using the channel estimation result in a single slot (e.g., the second method (902)) may be more advantageous in terms of channel estimation performance than using the channel estimation results of accumulated slots (e.g., the first method (901)). Similarly, in an environment with a low Doppler frequency (e.g., a communication environment with a low-speed mobile terminal), using channel estimation results of accumulated slots (e.g., the first method (901)) may be more advantageous in terms of channel estimation than using channel estimation results of a single slot (e.g., the second method (902)).

[0138] Referring to FIG. 12b, a graph (1250) represents a cumulative distribution function (CDF) according to a comparison index. The horizontal axis of the graph (1250) represents the comparison index. The vertical axis of the graph (1250) represents the CDF. The comparison index may be a result of comparing a first estimated index obtained through a first channel estimation result with a second estimated index obtained through a second channel estimation result. For example, the comparison index may be a value obtained by subtracting the first estimated index obtained through the first channel estimation result from the second estimated index obtained through the second channel estimation result. As an example, [Mathematical Formula 8] may be referred to for the comparison index.

[0139] The first line (1251) represents the CDF according to the comparison index when the Doppler frequency is 10 Hz. The second line (1252) represents the CDF according to the comparison index when the Doppler frequency is 100 Hz. The third line (1253) represents the CDF according to the comparison index when the Doppler frequency is 200 Hz. Comparing the first line (1251), the second line (1252), and the third line (1253), it can be confirmed that as the Doppler frequency increases, the value of the comparison index converging to 1 gradually increases. It can be confirmed that as the comparison index increases, the second estimated index is larger than the first estimated index. The size of the estimated index can indicate the accuracy of the estimation result of the estimated index. In other words, as in FIG. 12A, the graph (1250) may indicate that the second method (902) has a better channel estimation performance than the first method (901) in an environment with a high Doppler frequency (e.g., a communication environment with a high-speed mobile terminal). Similarly, the graph (1250) may indicate that the first method (901) has a better channel estimation performance than the second method (902) in an environment with a low Doppler frequency (e.g., a communication environment with a low-speed mobile terminal).

[0140] Figure 13 shows examples of channel estimation performance according to Doppler frequency.

[0141] Referring to Fig. 13, a graph (1380) represents communication quality according to Doppler frequency. The horizontal axis of the graph (1380) represents the Doppler frequency (unit: Hz), and the vertical axis represents the SNR (unit: dB) to satisfy a BLER of 10% or less. The first line (1381) represents the required SNR when using the channel estimation results of 8 slots, and the second line (1382) represents the required SNR when using the channel estimation result of 1 slot. The third line (1383) represents the communication quality when using the channel estimation result obtained by adaptively selecting one of the first method (901) and the second method (902) according to the comparison index described through Figs. 9a to 12b. The third line (1383) represents a lower SNR than the first line (1381) and the second line (1382) at any Doppler frequency. A method of adaptively selecting one of the first method (901) and the second method (902) can provide higher channel estimation performance than a fixed method (e.g., the first method (901) of the first line (1381), the second method (902) of the second line (1382)).

[0142] Fig. 14a illustrates the functional configuration of an electronic device. The configuration illustrated in Fig. 14a can be understood as the configuration of a base station (e.g., a base station (110)) or a DU (e.g., a DU (210) of Fig. 2) as part of a base station. Terms such as "... unit" and "... device" used hereinafter mean a unit that processes at least one function or operation, and this can be implemented by hardware, software, or a combination of hardware and software.

[0143] Referring to FIG. 14a, an electronic device (1400) (e.g., DU (210)) includes a transceiver (1410), a memory (1420), and a processor (1430).

[0144] The transceiver (1410) can perform functions for transmitting and receiving signals in a wired communication environment. The transceiver (1410) can include a wired interface for controlling direct connections between devices via a transmission medium (e.g., copper wire, optical fiber). For example, the transceiver (1410) can transmit electrical signals to other devices via copper wire, or perform conversion between electrical signals and optical signals. The electronic device (1400) can communicate with a radio unit (RU) via the transceiver (1410).

[0145] The transceiver (1410) may perform functions for transmitting and receiving signals in a wireless communication environment. For example, the transceiver (1410) may perform a conversion function between baseband signals and bit streams according to the physical layer specifications of the system. For example, when transmitting data, the transceiver (1410) encodes and modulates the transmitted bit stream to generate complex symbols. Furthermore, when receiving data, the transceiver (1410) demodulates and decodes the baseband signal to restore the received bit stream. Furthermore, the transceiver (1410) may include multiple transmission and reception paths.

[0146] The transceiver (1410) can transmit and receive signals. For example, the transceiver (1410) can transmit management plane (M-plane) messages. For example, the transceiver (1410) can transmit management plane (S-plane) messages. For example, the transceiver (1410) can transmit control plane (C-plane) messages. For example, the transceiver (1410) can transmit user plane (U-plane) messages. For example, the transceiver (1410) can receive user plane messages. Although only the transceiver (1410) is illustrated in FIG. 14A, according to other implementation examples, the electronic device (1400) may include two or more transceivers.

[0147] The transceiver (1410) transmits and receives signals as described above. Accordingly, all or part of the transceiver (1410) may be referred to as a 'communication unit', a 'transmitter', a 'receiver', or a 'transmitter-receiver'. In addition, in the following description, transmission and reception performed through a wireless channel are used to mean that processing as described above is performed by the transceiver (1410). According to one embodiment, the transceiver (1410) may obtain random access signals related to an NPRACH on which physical layer processing has been performed from an RU (e.g., RU (220)). For example, the transceiver (1410) may obtain signals (e.g., frequency domain signals) on which CP removal and FFT have been performed on the received signals.

[0148] Although not illustrated in FIG. 14A, the transceiver (1410) may further include a backhaul transceiver for connection to the core network or other base stations. The backhaul transceiver may provide an interface for communicating with other nodes within the network. That is, the backhaul transceiver converts a bit stream transmitted from the base station to other nodes, such as other access nodes, other base stations, upper nodes, the core network, etc., into a physical signal, and converts a physical signal received from other nodes into a bit stream.

[0149] The memory (1420) stores data such as basic programs, application programs, and setting information for the operation of the electronic device (1400). The memory (1420) may be referred to as a storage unit. The memory (1420) may be composed of volatile memory, non-volatile memory, or a combination of volatile memory and non-volatile memory. In addition, the memory (1420) may provide stored data upon request from the processor (1430).

[0150] The processor (1430) controls the overall operations of the electronic device (1400). The processor (1430) may be referred to as a control unit. For example, the processor (1430) transmits and receives signals via the transceiver (1410) (or via the backhaul communication unit). In addition, the processor (1430) records and reads data from the memory (1420). In addition, the processor (1430) may perform functions of a protocol stack required by a communication standard. Although only the processor (1430) is illustrated in FIG. 14A, the electronic device (1400) may include two or more processors according to other implementation examples.

[0151] According to one embodiment, the processor (1430) may perform physical layer processing on signals received from an RU (e.g., RU (220)). For example, the processor (1430) may perform subcarrier demapping (RE demapping) on ​​the received signals. For example, the processor (1430) may obtain a noise-interference component (e.g., a noise-interference covariance matrix) based on the received reference signals. Furthermore, for example, the processor (1430) may perform channel estimation based on the received reference signals. The processor (1430) may determine weights for a receive combiner. The processor (1430) may determine data corresponding to an uplink signal.

[0152] The configuration of the electronic device (1400) illustrated in FIG. 14A is merely an example, and examples of DUs performing embodiments of the present disclosure are not limited to the configuration illustrated in FIG. 14A. In some embodiments, some configurations may be added, deleted, or changed.

[0153] Fig. 14b illustrates the functional configuration of a wireless electronic device (e.g., RU (220), MMU). Hereinafter, RU (220) is exemplified as the wireless electronic device, but at least some of the descriptions described below may be applied to other wireless electronic devices. The configuration illustrated in Fig. 11b may be understood as the configuration of RU (220) of Fig. 2 as part of a base station. Terms such as "... unit" and "... device" used hereinafter mean a unit that processes at least one function or operation, and this may be implemented by hardware, software, or a combination of hardware and software.

[0154] Referring to FIG. 14b, a wireless electronic device (1450) (e.g., RU (220)) includes an RF transceiver (1460), a fronthaul transceiver (1465), a memory (1470), and a processor (1480).

[0155] The RF transceiver (1460) performs functions for transmitting and receiving signals via a wireless channel. For example, the RF transceiver (1460) upconverts a baseband signal into an RF band signal and transmits the upconverted signal via an antenna, and downconverts an RF band signal received via the antenna into a baseband signal. For example, the RF transceiver (1460) may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, and the like.

[0156] The RF transceiver (1460) may include multiple transmission and reception paths. Furthermore, the RF transceiver (1460) may include an antenna unit. The RF transceiver (1460) may include at least one antenna array composed of multiple antenna elements. In terms of hardware, the RF transceiver (1460) may be composed of digital circuits and analog circuits (e.g., a radio frequency integrated circuit (RFIC)). Here, the digital circuits and analog circuits may be implemented in a single package. In addition, the RF transceiver (1460) may include multiple RF chains. The RF transceiver (1460) may perform beamforming. The RF transceiver (1460) may apply beamforming weights to a signal to be transmitted and received in order to impart directionality to the signal according to the settings of the processor (1480). According to one embodiment, the RF transceiver (1460) may be equipped with multiple antennas.

[0157] According to one embodiment, the RF transceiver (1460) may transmit and receive signals over a radio access network. For example, the RF transceiver (1460) may transmit a downlink signal. The downlink signal may include a synchronization signal (SS), a reference signal (RS) (e.g., a cell-specific reference signal (CRS), a demodulation (DM)-RS), system information (e.g., a MIB, a SIB, remaining system information (RMSI), other system information (OSI)), a configuration message, control information, or downlink data. In addition, for example, the RF transceiver (1460) may receive an uplink signal. For example, the uplink signal may include a random access related signal (e.g., an NPRACH, an NPUSCH). According to one embodiment, the RF transceiver (1460) may receive signals including random access signals via multiple antennas provided in the RF transceiver (1460). Although only the RF transceiver (1460) is illustrated in FIG. 14B , in other implementations, the wireless electronic device (1450) may include two or more RF transceivers.

[0158] The fronthaul transceiver (1465) can transmit and receive signals. According to one embodiment, the fronthaul transceiver (1465) can transmit and receive signals on the fronthaul interface. For example, the fronthaul transceiver (1465) can receive a management plane (M-plane) message. For example, the fronthaul transceiver (1465) can receive a management plane (S-plane) message. For example, the fronthaul transceiver (1465) can receive a control plane (C-plane) message. For example, the fronthaul transceiver (1465) can transmit a user plane (U-plane) message. For example, the fronthaul transceiver (1465) can receive a user plane message. In one embodiment, the fronthaul transceiver (1465) may transmit a signal (e.g., a frequency domain signal) on which CP removal and FFT have been performed to a DU (e.g., DU (210)). Although only the fronthaul transceiver (1465) is illustrated in FIG. 14B , in other implementations, the wireless electronic device (1450) may include two or more fronthaul transceivers.

[0159] The RF transceiver (1460) and the fronthaul transceiver (1465) transmit and receive signals as described above. Accordingly, all or part of the RF transceiver (1460) and the fronthaul transceiver (1465) may be referred to as a 'communication unit', a 'transmitter', a 'receiver', or a 'transmitter-receiver unit'. In addition, in the following description, transmission and reception performed through a wireless channel are used to mean that the processing as described above is performed by the RF transceiver (1460). In the following description, transmission and reception performed through a wireless channel are used to mean that the processing as described above is performed by the RF transceiver (1460).

[0160] The memory (1470) stores data such as basic programs, applications, and setting information for the operation of the wireless electronic device (1450). The memory (1470) may be referred to as a storage unit. The memory (1470) may be composed of volatile memory, non-volatile memory, or a combination of volatile and non-volatile memory. In addition, the memory (1470) may provide stored data upon request from the processor (1480).

[0161] The processor (1480) controls the overall operations of the wireless electronic device (1450). The processor (1480) may be referred to as a control unit. For example, the processor (1480) transmits and receives signals through the RF transceiver (1460) or the fronthaul transceiver (1465). In addition, the processor (1480) writes and reads data to and from the memory (1470). In addition, the processor (1480) may perform functions of the protocol stack required by the communication standard. Although only the processor (1480) is illustrated in FIG. 14B , the wireless electronic device (1450) may include two or more processors according to other implementation examples. The processor (1480) may be a set of instructions or codes stored in the memory (1470), or may be a storage space storing instructions / codes or instructions / codes that are temporarily residing in the processor (1480), or may be a part of the circuitry constituting the processor (1480). In addition, the processor (1480) may include various modules for performing communication. The processor (1480) may control the wireless electronic device (1450) to perform operations according to the embodiments described below.

[0162] The configuration of the wireless electronic device (1450) illustrated in FIG. 14b is merely an example, and examples of RUs performing embodiments of the present disclosure are not limited to the configuration illustrated in FIG. 14b. In some embodiments, some configurations may be added, deleted, or changed.

[0163] In the present disclosure, a technique is described for adaptively selecting whether to use channel estimation results accumulated over multiple slots or the channel estimation result for the current slot in a weak-field situation (e.g., slot aggregation, situations where repeated transmissions are performed for low-power terminals (e.g., MTC terminals, RedCap (reduced capability) UEs, NB-IoT terminals)). An electronic device can provide robust channel estimation performance to changes in channel conditions by adaptively selecting a channel estimation method based on an estimation index. Even in situations where Doppler estimation of a fading channel is difficult, high channel estimation performance can be provided by selecting a channel estimation method that takes into account the influence of Doppler.

[0164] The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects that are not mentioned can be clearly understood by a person having ordinary skill in the art to which the present disclosure belongs from the description below.

[0165] In embodiments of the present disclosure, an electronic device is provided. The electronic device may include at least one processor including a processing circuit. The electronic device may include a memory storing instructions and including one or more storage media. The instructions, when individually or collectively executed by the at least one processor, may cause the electronic device to obtain uplink reference signal (RS) symbols in an estimated RS (reference signal) symbol of an estimation slot among a plurality of slots for uplink transmission, obtain a first channel estimation result for a set of RS symbols that are mapped across at least two slots among the plurality of slots for uplink transmission and are different from the estimated RS symbol, obtain a second channel estimation result for an RS symbol adjacent to the estimated RS symbol among RS symbols of the set of RS symbols, and obtain a channel estimation result for the estimation slot based on a comparison result between a first estimation index using the first channel estimation result and the uplink RSs and a second estimation index using the second channel estimation result and the uplink RSs.

[0166] For example, among the plurality of slots, at least two slots may be consecutive in the time domain. RS symbols within the set of RS symbols may be consecutive within the entire RS symbols of the at least two consecutive slots.

[0167] For example, the instructions, when executed by the at least one processor, may cause the electronic device to obtain the channel estimation result based on channel estimation for RS symbols of slots including the estimation slot if the first estimation index is greater than the second estimation index, and to obtain the channel estimation result based on channel estimation for RS symbols of the estimation slot if the first estimation index is not greater than the second estimation index.

[0168] For example, the first estimation index may represent the number of REs (resource elements) in which the phase of the first equalization value using the first channel estimation result is within a critical range. The second estimation index may represent the number of REs in which the phase of the second equalization value using the second channel estimation result is within a critical range.

[0169] For example, the first equalization value may be determined through the first channel estimation result, the uplink sequence in the estimated RS symbol, and the received signal in the estimated RS symbol. The second equalization value may be determined through the second channel estimation result, the uplink sequence in the estimated RS symbol, and the received signal in the estimated RS symbol.

[0170] For example, the uplink sequence in the estimated RS symbol can be determined according to the antenna port corresponding to the received signal in the estimated RS symbol and the position of the estimated RS symbol.

[0171] For example, the instructions, when individually or collectively executed by the at least one processor, may cause the electronic device to demodulate uplink data in the estimation slot based on the channel estimation result.

[0172] For example, the number of the plurality of slots according to slot aggregation may be 2, 4, or 8. Uplink data in the at least two slots may be received within the same frequency range. The uplink RSs may include demodulation reference signals (DMRSs) for the uplink data.

[0173] For example, an RS symbol adjacent to the estimated RS symbol may be included within the estimated slot that includes the estimated RS symbol.

[0174] For example, the estimated RS symbol may be the earliest symbol among the RS symbols of the estimated slot. An RS symbol adjacent to the estimated RS symbol may be included in a previous slot adjacent to the estimated slot.

[0175] In embodiments of the present disclosure, a method performed by an electronic device is provided. The method may include: obtaining uplink reference signal (RS) symbols from an estimated RS (reference signal) symbol of an estimation slot among a plurality of slots for uplink transmission; obtaining a first channel estimation result for a set of RS symbols that are mapped across at least two slots among the plurality of slots for uplink transmission and are different from the estimated RS symbol; obtaining a second channel estimation result for an RS symbol adjacent to the estimated RS symbol among RS symbols of the set of RS symbols; and obtaining a channel estimation result for the estimation slot based on a comparison result between a first estimation index using the first channel estimation result and the uplink RSs and a second estimation index using the second channel estimation result and the uplink RSs.

[0176] For example, among the plurality of slots, at least two slots may be consecutive in the time domain. RS symbols within the set of RS symbols may be consecutive within the entire RS symbols of the at least two consecutive slots.

[0177] For example, the method may include an operation of obtaining the channel estimation result based on channel estimation for RS symbols of slots including the estimation slot when the first estimation index is greater than the second estimation index, and an operation of obtaining the channel estimation result based on channel estimation for RS symbols of the estimation slot when the first estimation index is not greater than the second estimation index.

[0178] For example, the first estimation index may represent the number of REs (resource elements) in which the phase of the first equalization value using the first channel estimation result is within a critical range. The second estimation index may represent the number of REs in which the phase of the second equalization value using the second channel estimation result is within a critical range.

[0179] For example, the first equalization value may be determined through the first channel estimation result, the uplink sequence in the estimated RS symbol, and the received signal in the estimated RS symbol. The second equalization value may be determined through the second channel estimation result, the uplink sequence in the estimated RS symbol, and the received signal in the estimated RS symbol.

[0180] For example, the uplink sequence in the estimated RS symbol can be determined according to the antenna port corresponding to the received signal in the estimated RS symbol and the resource location of the estimated RS symbol.

[0181] For example, the method may include an operation of demodulating uplink data in the estimation slot based on the channel estimation result.

[0182] For example, the number of the plurality of slots according to slot aggregation may be 2, 4, or 8. Uplink data in the at least two slots may be received within the same frequency range. The uplink RSs may include demodulation reference signals (DMRSs) for the uplink data.

[0183] For example, an RS symbol adjacent to the estimated RS symbol may be included within the estimated slot that includes the estimated RS symbol.

[0184] For example, the estimated RS symbol may be the earliest symbol among the RS symbols of the estimated slot. An RS symbol adjacent to the estimated RS symbol may be included in a previous slot adjacent to the estimated slot.

[0185] In embodiments of the present disclosure, a non-transitory computer-readable storage medium is provided. The non-transitory computer-readable storage medium may include instructions that, when executed by a processor, cause an electronic device to perform operations including: obtaining uplink reference signal (RS) symbols from an estimated RS symbol of an estimation slot among a plurality of slots for uplink transmission; obtaining a first channel estimation result for a set of RS symbols that are mapped across at least two slots among the plurality of slots for uplink transmission and are different from the estimated RS symbol; obtaining a second channel estimation result for an RS symbol adjacent to the estimated RS symbol among RS symbols of the set of RS symbols; and obtaining a channel estimation result for the estimation slot based on a comparison result between a first estimation index using the first channel estimation result and the uplink RSs and a second estimation index using the second channel estimation result and the uplink RSs.

[0186] In embodiments of the present disclosure, an electronic device is provided. The electronic device may include at least one processor including a processing circuit. The at least one processor may be configured to obtain uplink reference signal (RS) symbols in an estimated RS symbol of an estimation slot among a plurality of slots for uplink transmission, obtain a first channel estimation result for a set of RS symbols that are mapped across at least two slots among the plurality of slots for uplink transmission and are different from the estimated RS symbol, obtain a second channel estimation result for an RS symbol adjacent to the estimated RS symbol among RS symbols of the set of RS symbols, and obtain a channel estimation result for the estimation slot based on a comparison result between a first estimation index using the first channel estimation result and the uplink RSs and a second estimation index using the second channel estimation result and the uplink RSs.

[0187] For example, the at least one processor may be configured to obtain the channel estimation result based on channel estimation for RS symbols of slots including the estimation slot when the first estimation index is greater than the second estimation index, and to obtain the channel estimation result based on channel estimation for RS symbols of the estimation slot when the first estimation index is not greater than the second estimation index.

[0188] For example, the at least one processor, when individually or collectively executed by the at least one processor, may be configured to cause the electronic device to demodulate uplink data in the estimation slot based on the channel estimation result.

[0189] For one or more embodiments, at least one of the components described in one or more of the preceding drawings may be configured to perform one or more operations, techniques, processes, and / or methods as described herein. For example, a processor (e.g., a baseband processor) described herein with respect to one or more of the preceding drawings may be configured to operate according to one or more examples described herein. For another example, circuitry associated with a user equipment (UE), a base station, a network element, and the like, as described above with respect to one or more of the preceding drawings, may be configured to operate according to one or more examples described herein.

[0190] Any of the embodiments described above may be combined with any other embodiment (or combination of embodiments) unless explicitly stated otherwise. The foregoing description of one or more implementations provides examples and descriptions, but is not intended to be exhaustive or limit the scope of the embodiments to the precise forms disclosed. Modifications and variations are possible in light of the above teachings or may be learned from practicing various embodiments.

[0191] The 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.

[0192] When implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium are configured to be executed by one or more processors in an electronic device. The one or more programs include instructions that cause the electronic device to execute methods according to embodiments described in the claims or specification of the present disclosure. The one or more programs may be provided as a computer program product. The computer program product may be traded between a seller and a buyer as a commodity. The computer program product may be distributed in the form of a machine-readable storage medium (e.g., compact disc read only memory (CD-ROM)), or may be distributed online (e.g., downloaded or uploaded) via an application store (e.g., Play Store™) or directly between two user devices (e.g., smart phones). In the case of online distribution, at least a portion of the computer program product may be temporarily stored or temporarily created in a device-readable storage medium, such as the memory of a manufacturer's server, an application store's server, or an intermediary server.

[0193] These 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, or may be stored in memories formed by a combination of some or all of these. In addition, each configuration memory may include multiple copies.

[0194] Additionally, the program may be stored on an attachable storage device that is accessible via a communication network, such as the Internet, an intranet, a local area network (LAN), a wide area network (WAN), a storage area network (SAN), or a combination thereof. Such a storage device may be connected to a device implementing an embodiment of the present disclosure via an external port. Additionally, a separate storage device on the communication network may be connected to a device implementing an embodiment of the present disclosure.

[0195] In the specific embodiments of the present disclosure described above, components included in the disclosure are expressed singularly or plurally, depending on the specific embodiment presented. However, the singular or plural expressions are selected to suit the presented situation for convenience of explanation, and the present disclosure is not limited to singular or plural components. Components expressed in plural may be composed of singular elements, or components expressed in singular may be composed of plural elements.

[0196] According to embodiments, one or more of the components or operations of the aforementioned components may be omitted, or one or more other components or operations may be added. Alternatively or additionally, a plurality of components (e.g., modules or programs) may be integrated into a single component. In such a case, the integrated component may perform one or more functions of each of the plurality of components identically or similarly to those performed by the corresponding component among the plurality of components prior to the integration. According to embodiments, the operations performed by a module, program, or other component may be executed sequentially, in parallel, iteratively, or heuristically, or one or more of the operations may be executed in a different order, omitted, or one or more other operations may be added.

[0197] Meanwhile, although the detailed description of the present disclosure has described specific embodiments, it is obvious that various modifications are possible within the scope of the present disclosure.

Claims

1. In electronic devices, At least one processor comprising a processing circuit; and A memory comprising one or more storage media for storing instructions, The above instructions, when individually or collectively executed by the at least one processor, cause the electronic device to: Obtain uplink RSs from the estimated RS (reference signal) symbol of the estimated slot among multiple slots for uplink transmission, Obtaining a first channel estimation result for a set of RS symbols other than the estimated RS symbol, mapped across at least two slots among a plurality of slots for the above uplink transmission, Obtaining a second channel estimation result for an RS symbol adjacent to the estimated RS symbol among the RS symbols of the set of RS symbols, Based on the comparison result of the first channel estimation result and the first estimation index using the uplink RSs and the second estimation index using the second channel estimation result and the uplink RSs, a channel estimation result for the estimation slot is obtained. Electronic devices.

2. In claim 1, Among the plurality of slots, at least two slots are continuous in the time domain, The RS symbols within the set of said RS symbols are consecutive within the entire RS symbols of at least two consecutive slots. Electronic devices.

3. In claim 1, When the above instructions are executed by the at least one processor, the electronic device: If the first estimated index is greater than the second estimated index, the channel estimation result is obtained based on channel estimation for RS symbols of slots including the estimated slot, If the first estimated index is not greater than the second estimated index, the channel estimation result is obtained based on the channel estimation for the RS symbols of the estimation slot. Electronic devices.

4. In claim 3, The above first estimation index represents the number of REs (resource elements) whose phase of the first equalization value using the first channel estimation result is within a critical range, The second estimation index indicates the number of REs in which the phase of the second equalization value using the second channel estimation result is within the critical range. Electronic devices.

5. In claim 4, The first equalization value is determined through the first channel estimation result, the uplink sequence in the estimated RS symbol, and the received signal in the estimated RS symbol, The second equalization value is determined through the second channel estimation result, the uplink sequence in the estimated RS symbol, and the received signal in the estimated RS symbol. Electronic devices.

6. In claim 5, The uplink sequence in the above estimated RS symbol is determined according to the antenna port corresponding to the received signal in the above estimated RS symbol and the position of the above estimated RS symbol. Electronic devices.

7. In claim 3, The above instructions, when individually or collectively executed by the at least one processor, cause the electronic device to: Causing to demodulate uplink data in the estimation slot based on the channel estimation result, Electronic devices.

8. In claim 1, The number of the plurality of slots according to slot aggregation is 2, 4, or 8, Uplink data in at least two slots above is received within the same frequency range, The above uplink RSs include DMRSs (demodulation reference signals) for the uplink data. Electronic devices.

9. In claim 1, An RS symbol adjacent to the estimated RS symbol is included in the estimated slot containing the estimated RS symbol. Electronic devices.

10. In claim 1, The above estimated RS symbol is the leading symbol among the RS symbols of the above estimated slot, The RS symbol adjacent to the above estimated RS symbol is included in the previous slot adjacent to the above estimated slot. Electronic devices.

11. In a method performed by an electronic device, An operation of obtaining uplink RSs from an estimated RS (reference signal) symbol of an estimated slot among multiple slots for uplink transmission, An operation of obtaining a first channel estimation result for a set of RS symbols different from the estimated RS symbol, wherein the first channel estimation result is mapped across at least two slots among a plurality of slots for the above uplink transmission; An operation of obtaining a second channel estimation result for an RS symbol adjacent to the estimated RS symbol among the RS symbols of the set of RS symbols; An operation of obtaining a channel estimation result for the estimation slot based on a comparison result between a first estimation index using the first channel estimation result and the uplink RSs and a second estimation index using the second channel estimation result and the uplink RSs, method.

12. In claim 11, Among the plurality of slots, at least two slots are continuous in the time domain, The RS symbols within the set of said RS symbols are consecutive within the entire RS symbols of at least two consecutive slots. method.

13. In claim 11, An operation of obtaining the channel estimation result based on channel estimation for RS symbols of slots including the estimation slot, when the first estimation index is greater than the second estimation index; If the first estimated index is not greater than the second estimated index, the method further includes obtaining the channel estimation result based on channel estimation for RS symbols of the estimation slot. method.

14. In claim 13, The above first estimation index represents the number of REs (resource elements) whose phase of the first equalization value using the first channel estimation result is within a critical range, The second estimation index indicates the number of REs in which the phase of the second equalization value using the second channel estimation result is within the critical range. method.

15. In claim 14, The first equalization value is determined through the first channel estimation result, the uplink sequence in the estimated RS symbol, and the received signal in the estimated RS symbol, The second equalization value is determined through the second channel estimation result, the uplink sequence in the estimated RS symbol, and the received signal in the estimated RS symbol. method.

Images