KR20230155753A - Method and apparatus of determining transmission power of base station for wireless communication - Google Patents

Abstract

The present disclosure provides a method of determining transmission power for a specific terminal based on an MCS value to be applied to data to be transmitted for a specific terminal.

Description

Method and device for determining base station transmission power {METHOD AND APPARATUS OF DETERMINING TRANSMISSION POWER OF BASE STATION FOR WIRELESS COMMUNICATION}

The present invention provides a method for determining base station transmission power in a 3GPP NR system.

In one aspect, the present embodiments may provide a method of determining the transmission power for a specific terminal based on an MCS value to be applied to data to be transmitted for the specific terminal.

Figure 1 is a diagram briefly illustrating the structure of an NR wireless communication system to which this embodiment can be applied.
Figure 2 is a diagram for explaining the frame structure in an NR system to which this embodiment can be applied.
FIG. 3 is a diagram illustrating a resource grid supported by wireless access technology to which this embodiment can be applied.
Figure 4 is a diagram for explaining the bandwidth part supported by the wireless access technology to which this embodiment can be applied.
Figure 5 is a diagram illustrating a synchronization signal block in a wireless access technology to which this embodiment can be applied.
Figure 6 is a diagram for explaining a random access procedure in wireless access technology to which this embodiment can be applied.
Figure 7 is a diagram to explain CORESET.
FIG. 8 is a diagram illustrating an example of symbol level alignment among different SCSs to which this embodiment can be applied.
Figure 9 is a diagram showing a conceptual example of a bandwidth part to which this embodiment can be applied.
Figure 10 is a diagram showing the configuration of a base station according to another embodiment.
Figure 11 is a diagram showing the configuration of a user terminal according to another embodiment.

Hereinafter, some embodiments of the present disclosure will be described in detail with reference to illustrative drawings. In adding reference numerals to components in each drawing, the same components may have the same reference numerals as much as possible even if they are shown in different drawings. Additionally, in describing the present embodiments, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present technical idea, the detailed description may be omitted. When “comprises,” “has,” “consists of,” etc. mentioned in the specification are used, other parts may be added unless “only” is used. When a component is expressed in the singular, it can also include the plural, unless specifically stated otherwise.

Additionally, in describing the components of the present disclosure, terms such as first, second, A, B, (a), and (b) may be used. These terms are only used to distinguish the component from other components, and the nature, sequence, order, or number of the components are not limited by the term.

In the description of the positional relationship of components, when two or more components are described as being “connected,” “coupled,” or “connected,” the two or more components are directly “connected,” “coupled,” or “connected.” ", but it should be understood that two or more components and other components may be further "interposed" and "connected," "combined," or "connected." Here, other components may be included in one or more of two or more components that are “connected,” “coupled,” or “connected” to each other.

In the description of temporal flow relationships related to components, operation methods, production methods, etc., for example, temporal precedence relationships such as “after”, “after”, “after”, “before”, etc. Or, when a sequential relationship is described, non-continuous cases may be included unless “immediately” or “directly” is used.

On the other hand, when a numerical value or corresponding information (e.g., level, etc.) for a component is mentioned, even if there is no separate explicit description, the numerical value or corresponding information is related to various factors (e.g., process factors, internal or external shocks, It can be interpreted as including the error range that may occur due to noise, etc.).

The wireless communication system in this specification refers to a system for providing various communication services such as voice and data packets using wireless resources, and may include a terminal, a base station, or a core network.

The present embodiments disclosed below can be applied to wireless communication systems using various wireless access technologies. For example, the present embodiments include code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), and single carrier frequency division multiple access (SC-FDMA). Alternatively, it can be applied to a variety of different wireless access technologies such as NOMA (non-orthogonal multiple access). In addition, wireless access technology not only refers to a specific access technology, but also refers to communication technology for each generation established by various communication consultative organizations such as 3GPP, 3GPP2, WiFi, Bluetooth, IEEE, and ITU. For example, CDMA can be implemented as a wireless technology such as universal terrestrial radio access (UTRA) or CDMA2000. TDMA may be implemented with wireless technologies such as global system for mobile communications (GSM)/general packet radio service (GPRS)/enhanced data rates for GSM evolution (EDGE). OFDMA can be implemented with wireless technologies such as IEEE (institute of electrical and electronics engineers) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, E-UTRA (evolved UTRA), etc. IEEE 802.16m is an evolution of IEEE 802.16e and provides backward compatibility with systems based on IEEE 802.16e. UTRA is part of the universal mobile telecommunications system (UMTS). 3GPP (3rd generation partnership project) LTE (long term evolution) is a part of E-UMTS (evolved UMTS) that uses E-UTRA (evolved-UMTS terrestrial radio access), employing OFDMA in the downlink and SC- in the uplink. FDMA is adopted. In this way, the present embodiments can be applied to wireless access technologies currently disclosed or commercialized, and can also be applied to wireless access technologies currently under development or to be developed in the future.

Meanwhile, the terminal in this specification is a comprehensive concept meaning a device including a wireless communication module that communicates with a base station in a wireless communication system, and is used in WCDMA, LTE, NR, HSPA, and IMT-2020 (5G or New Radio), etc. It should be interpreted as a concept that includes not only UE (User Equipment), but also MS (Mobile Station), UT (User Terminal), SS (Subscriber Station), and wireless devices in GSM. In addition, a terminal may be a user portable device such as a smart phone depending on the type of use, and in a V2X communication system, it may mean a vehicle, a device including a wireless communication module within the vehicle, etc. Additionally, in the case of a machine type communication system, it may mean an MTC terminal, M2M terminal, URLLC terminal, etc. equipped with a communication module to perform machine type communication.

The base station or cell in this specification refers to an end point that communicates with a terminal in terms of a network, and includes Node-B (Node-B), evolved Node-B (eNB), gNode-B (gNB), Low Power Node (LPN), Sector, site, various types of antennas, BTS (Base Transceiver System), access point, point (e.g. transmission point, reception point, transmission/reception point), relay node ), mega cell, macro cell, micro cell, pico cell, femto cell, RRH (Remote Radio Head), RU (Radio Unit), and small cell. Additionally, a cell may mean including a bandwidth part (BWP) in the frequency domain. For example, a serving cell may mean the UE's Activation BWP.

Since the various cells listed above have a base station that controls one or more cells, base station can be interpreted in two ways. 1) It may be the device itself that provides mega cells, macro cells, micro cells, pico cells, femto cells, and small cells in relation to the wireless area, or 2) it may indicate the wireless area itself. In 1), all devices providing a predetermined wireless area are controlled by the same entity or all devices that interact to collaboratively configure the wireless area are directed to the base station. Depending on how the wireless area is configured, a point, transmission/reception point, transmission point, reception point, etc. become an example of a base station. In 2), the wireless area itself where signals are received or transmitted from the user terminal's perspective or the neighboring base station's perspective may be indicated to the base station.

In this specification, a cell refers to the coverage of a signal transmitted from a transmission/reception point, a component carrier having coverage of a signal transmitted from a transmission point or transmission/reception point, or the transmission/reception point itself. You can.

Uplink (UL, or uplink) refers to a method of transmitting and receiving data from a terminal to a base station, and downlink (Downlink, DL, or downlink) refers to a method of transmitting and receiving data from a base station to a terminal. do. Downlink may refer to communication or a communication path from multiple transmission/reception points to a terminal, and uplink may refer to communication or a communication path from a terminal to multiple transmission/reception points. At this time, in the downlink, the transmitter may be part of a multiple transmission/reception point, and the receiver may be part of the terminal. Additionally, in the uplink, a transmitter may be part of a terminal, and a receiver may be part of a multiple transmission/reception point.

Uplink and downlink transmit and receive control information through control channels such as PDCCH (Physical Downlink Control CHannel) and PUCCH (Physical Uplink Control CHannel), and PDSCH (Physical Downlink Shared CHannel), PUSCH (Physical Uplink Shared CHannel), etc. Data is transmitted and received by configuring the same data channel. Hereinafter, the situation in which signals are transmitted and received through channels such as PUCCH, PUSCH, PDCCH and PDSCH may be expressed as 'transmitting and receiving PUCCH, PUSCH, PDCCH and PDSCH'. do.

For clarity of explanation, the technical idea below is mainly described in the 3GPP LTE/LTE-A/NR (New RAT) communication system, but the technical features are not limited to the corresponding communication system.

Following research on 4G (4th-Generation) communication technology, 3GPP develops 5G (5th-Generation) communication technology to meet the requirements of ITU-R's next-generation wireless access technology. Specifically, 3GPP develops LTE-A pro, which is a 5G communication technology that improves LTE-Advanced technology to meet the requirements of ITU-R, and a new NR communication technology that is separate from 4G communication technology. Both LTE-A pro and NR refer to 5G communication technology, and hereinafter, 5G communication technology will be explained focusing on NR in cases where a specific communication technology is not specified.

The operating scenario in NR defines a variety of operating scenarios by adding consideration of satellites, automobiles, and new verticals to the existing 4G LTE scenario, and in terms of service, the eMBB (Enhanced Mobile Broadband) scenario has a high terminal density but is wide. It is deployed in a wide range of applications, supporting mMTC (Massive Machine Communication) scenarios that require low data rates and asynchronous connections, and URLLC (Ultra Reliability and Low Latency) scenarios that require high responsiveness and reliability and can support high-speed mobility. .

To satisfy this scenario, NR is launching a wireless communication system with new waveform and frame structure technology, low latency technology, ultra-high frequency band (mmWave) support technology, and forward compatible technology. In particular, the NR system proposes various technical changes in terms of flexibility to provide forward compatibility. The main technical features of NR are explained below with reference to the drawings.

<NR system general>

Figure 1 is a diagram briefly illustrating the structure of an NR system to which this embodiment can be applied.

Referring to Figure 1, the NR system is divided into 5GC (5G Core Network) and NR-RAN parts, and NG-RAN controls the user plane (SDAP/PDCP/RLC/MAC/PHY) and UE (User Equipment). It consists of gNB and ng-eNB providing flat (RRC) protocol termination. gNB interconnection or gNB and ng-eNB are interconnected through Xn interface. gNB and ng-eNB are each connected to 5GC through the NG interface. 5GC may be composed of an Access and Mobility Management Function (AMF), which is responsible for the control plane such as terminal access and mobility control functions, and a User Plane Function (UPF), which is responsible for controlling user data. NR includes support for both the frequency band below 6 GHz (FR1, Frequency Range 1) and the frequency band above 6 GHz (FR2, Frequency Range 2).

gNB refers to a base station that provides NR user plane and control plane protocol termination to the terminal, and ng-eNB refers to a base station that provides E-UTRA user plane and control plane protocol termination to the terminal. The base station described in this specification should be understood to encompass gNB and ng-eNB, and may be used to refer to gNB or ng-eNB separately, if necessary.

<NR wave form, numerology and frame structure>

In NR, the CP-OFDM wave form using a cyclic prefix is used for downlink transmission, and CP-OFDM or DFT-s-OFDM is used for uplink transmission. OFDM technology is easy to combine with MIMO (Multiple Input Multiple Output) and has the advantage of being able to use a low-complexity receiver with high frequency efficiency.

Meanwhile, in NR, the requirements for data rate, delay rate, coverage, etc. are different for each of the three scenarios described above, so it is necessary to efficiently satisfy the requirements for each scenario through the frequency band that constitutes an arbitrary NR system. . To this end, a technology for efficiently multiplexing wireless resources based on a plurality of different numerologies has been proposed.

Specifically, the NR transmission numerology is determined based on sub-carrier spacing and CP (Cyclic prefix), and as shown in Table 1 below, the μ value is used as an exponent value of 2 based on 15 kHz, resulting in an exponential is changed to

μ Subcarrier spacing Cyclic prefix Supported for data Supported for synchronization 0 15 Normal Yes Yes One 30 Normal Yes Yes 2 60 Normal, Extended Yes No 3 120 Normal Yes Yes 4 240 Normal No Yes

As shown in Table 1 above, NR's numerology can be divided into five types depending on the subcarrier spacing. This is different from the subcarrier spacing of LTE, one of the 4G communication technologies, which is fixed at 15kHz. Specifically, the subcarrier intervals used for data transmission in NR are 15, 30, 60, and 120 kHz, and the subcarrier intervals used for synchronization signal transmission are 15, 30, 120, and 240 kHz. Additionally, the extended CP applies only to the 60kHz subcarrier spacing. Meanwhile, the frame structure in NR is defined as a frame with a length of 10ms consisting of 10 subframes with the same length of 1ms. One frame can be divided into half-frames of 5ms, and each half-frame contains 5 subframes. In the case of 15 kHz subcarrier spacing, one subframe consists of one slot, and each slot consists of 14 OFDM symbols.

Figure 2 is a diagram for explaining the frame structure in an NR system to which this embodiment can be applied.

Referring to FIG. 2, a slot is fixedly composed of 14 OFDM symbols in the case of normal CP, but the length of the slot in the time domain may vary depending on the subcarrier spacing. For example, in the case of numerology with a 15 kHz subcarrier spacing, a slot is 1 ms long and has the same length as a subframe. In contrast, in the case of numerology with a 30 kHz subcarrier spacing, a slot consists of 14 OFDM symbols, but two slots can be included in one subframe with a length of 0.5 ms. That is, subframes and frames are defined with a fixed time length, and slots are defined by the number of symbols, so the time length may vary depending on the subcarrier interval.

Meanwhile, NR defines the basic unit of scheduling as a slot, and also introduces a mini-slot (or sub-slot or non-slot based schedule) to reduce transmission delay in the wireless section. When a wide subcarrier spacing is used, the length of one slot is shortened in inverse proportion, so transmission delay in the wireless section can be reduced. Mini-slots (or sub-slots) are designed to efficiently support URLLC scenarios and can be scheduled in units of 2, 4, or 7 symbols.

Additionally, unlike LTE, NR defines uplink and downlink resource allocation at the symbol level within one slot. In order to reduce HARQ delay, a slot structure that can transmit HARQ ACK/NACK directly within the transmission slot has been defined, and this slot structure is described as a self-contained structure.

NR is designed to support a total of 256 slot formats, of which 62 slot formats are used in 3GPP Rel-15. In addition, it supports a common frame structure that forms an FDD or TDD frame through a combination of various slots. For example, a slot structure in which all slot symbols are set to downlink, a slot structure in which all symbols are set to uplink, and a slot structure in which downlink symbols and uplink symbols are combined are supported. Additionally, NR supports scheduling data transmission distributed over one or more slots. Therefore, the base station can use a slot format indicator (SFI) to inform the terminal whether the slot is a downlink slot, an uplink slot, or a flexible slot. The base station can indicate the slot format by indicating the index of the table configured through UE-specific RRC signaling using SFI, and can indicate it dynamically through DCI (Downlink Control Information) or statically or through RRC. It can also be indicated semi-statically.

<NR physical resources>

Regarding physical resources in NR, antenna port, resource grid, resource element, resource block, bandwidth part, etc. are considered. do.

An antenna port is defined so that a channel carrying a symbol on the antenna port can be inferred from a channel carrying another symbol on the same antenna port. If the large-scale properties of the channel carrying the symbols on one antenna port can be inferred from the channel carrying the symbols on the other antenna port, the two antenna ports are quasi co-located or QC/QCL. It can be said that they are in a quasi co-location relationship. Here, the wide range characteristics include one or more of delay spread, Doppler spread, frequency shift, average received power, and received timing.

FIG. 3 is a diagram illustrating a resource grid supported by wireless access technology to which this embodiment can be applied.

Referring to FIG. 3, since NR supports multiple numerology on the same carrier, a resource grid may exist for each numerology. Additionally, resource grids may exist depending on antenna ports, subcarrier spacing, and transmission direction.

A resource block consists of 12 subcarriers and is defined only in the frequency domain. Additionally, a resource element consists of one OFDM symbol and one subcarrier. Therefore, as shown in FIG. 3, the size of one resource block may vary depending on the subcarrier spacing. Additionally, NR defines "Point A", which serves as a common reference point for the resource block grid, common resource blocks, virtual resource blocks, etc.

Figure 4 is a diagram for explaining the bandwidth part supported by the wireless access technology to which this embodiment can be applied.

In NR, unlike LTE, where the carrier bandwidth is fixed at 20Mhz, the maximum carrier bandwidth is set from 50Mhz to 400Mhz for each subcarrier interval. Therefore, it is not assumed that all terminals use all of these carrier bandwidths. Accordingly, in NR, the terminal can use a designated bandwidth part (BWP) within the carrier bandwidth as shown in FIG. 4. Additionally, the bandwidth part is linked to one numerology and consists of a subset of consecutive common resource blocks, and can be activated dynamically over time. The terminal is configured with up to four bandwidth parts for each uplink and downlink, and data is transmitted and received using the bandwidth parts activated at a given time.

In the case of a paired spectrum, the uplink and downlink bandwidth parts are set independently, and in the case of an unpaired spectrum, to prevent unnecessary frequency re-tunning between downlink and uplink operations. For this purpose, the bandwidth parts of the downlink and uplink are set in pairs so that they can share the center frequency.

<NR initial access>

In NR, the terminal performs cell search and random access procedures to connect to the base station and perform communication.

Cell search is a procedure in which the terminal synchronizes to the cell of the base station, obtains a physical layer cell ID, and obtains system information using a synchronization signal block (SSB) transmitted by the base station.

Figure 5 is a diagram illustrating a synchronization signal block in a wireless access technology to which this embodiment can be applied.

Referring to FIG. 5, the SSB is composed of a primary synchronization signal (PSS) and a secondary synchronization signal (SSS), each occupying 1 symbol and 127 subcarriers, and a PBCH spanning 3 OFDM symbols and 240 subcarriers.

The terminal monitors the SSB in the time and frequency domains and receives the SSB.

SSB can be transmitted up to 64 times in 5ms. Multiple SSBs are transmitted through different transmission beams within 5ms, and the terminal performs detection assuming that SSBs are transmitted every 20ms period based on one specific beam used for transmission. The number of beams that can be used for SSB transmission within 5ms time can increase as the frequency band becomes higher. For example, up to 4 different SSB beams can be transmitted under 3 GHz, up to 8 different beams can be used in the frequency band from 3 to 6 GHz, and up to 64 different beams can be used in the frequency band above 6 GHz.

Two SSBs are included in one slot, and the start symbol and number of repetitions within the slot are determined according to the subcarrier spacing as follows.

Meanwhile, unlike SS in conventional LTE, SSB is not transmitted at the center frequency of the carrier bandwidth. In other words, SSBs can be transmitted even in places other than the center of the system band, and when broadband operation is supported, multiple SSBs can be transmitted in the frequency domain. Accordingly, the terminal monitors the SSB using a synchronization raster, which is a candidate frequency location for monitoring the SSB. The carrier raster and synchronization raster, which are the center frequency location information of the channel for initial access, have been newly defined in NR, and the synchronization raster has a wider frequency interval than the carrier raster, supporting fast SSB search of the terminal. You can.

The UE can obtain the MIB through the PBCH of the SSB. MIB (Master Information Block) contains the minimum information required for the terminal to receive the remaining system information (RMSI, Remaining Minimum System Information) broadcast by the network. In addition, the PBCH includes information about the location of the first DM-RS symbol in the time domain, information for the terminal to monitor SIB1 (e.g., SIB1 numerology information, information related to SIB1 CORESET, search space information, PDCCH (related parameter information, etc.), offset information between the common resource block and the SSB (the position of the absolute SSB within the carrier is transmitted through SIB1), etc. Here, the SIB1 numerology information is equally applied to some messages used in the random access procedure for accessing the base station after the terminal completes the cell search procedure. For example, numerology information of SIB1 may be applied to at least one of messages 1 to 4 for the random access procedure.

The above-mentioned RMSI may mean SIB1 (System Information Block 1), and SIB1 is broadcast periodically (ex, 160ms) in the cell. SIB1 contains information necessary for the terminal to perform the initial random access procedure and is transmitted periodically through PDSCH. In order for the terminal to receive SIB1, it must receive numerology information used for SIB1 transmission and CORESET (Control Resource Set) information used for scheduling SIB1 through the PBCH. The UE uses SI-RNTI in CORESET to check scheduling information for SIB1 and acquires SIB1 on the PDSCH according to the scheduling information. Except for SIB1, the remaining SIBs may be transmitted periodically or according to the request of the terminal.

Figure 6 is a diagram for explaining a random access procedure in wireless access technology to which this embodiment can be applied.

Referring to FIG. 6, when cell search is completed, the terminal transmits a random access preamble for random access to the base station. The random access preamble is transmitted through PRACH. Specifically, the random access preamble is transmitted to the base station through PRACH, which consists of continuous radio resources in a specific slot that is repeated periodically. Generally, when a UE initially accesses a cell, a contention-based random access procedure is performed, and when random access is performed for beam failure recovery (BFR), a non-contention-based random access procedure is performed.

The terminal receives a random access response to the transmitted random access preamble. The random access response may include a random access preamble identifier (ID), UL Grant (uplink radio resource), temporary C-RNTI (Temporary Cell - Radio Network Temporary Identifier), and TAC (Time Alignment Command). Since one random access response may include random access response information for one or more terminals, the random access preamble identifier may be included to indicate to which terminal the included UL Grant, temporary C-RNTI, and TAC are valid. The random access preamble identifier may be an identifier for the random access preamble received by the base station. TAC may be included as information for the terminal to adjust uplink synchronization. The random access response may be indicated by a random access identifier on the PDCCH, that is, RA-RNTI (Random Access - Radio Network Temporary Identifier).

The terminal that has received a valid random access response processes the information included in the random access response and performs scheduled transmission to the base station. For example, the terminal applies TAC and stores temporary C-RNTI. Additionally, using the UL Grant, data stored in the terminal's buffer or newly created data is transmitted to the base station. In this case, information that can identify the terminal must be included.

Finally, the terminal receives a downlink message to resolve contention.

<NR CORESET>

The downlink control channel in NR is transmitted in CORESET (Control Resource Set) with a length of 1 to 3 symbols, and transmits uplink/downlink scheduling information, SFI (Slot format Index), and TPC (Transmit Power Control) information. .

In this way, in order to secure the flexibility of the system, NR introduced the CORESET concept. CORESET (Control Resource Set) refers to time-frequency resources for downlink control signals. The terminal may decode the control channel candidate using one or more search spaces in the CORESET time-frequency resource. QCL (Quasi CoLocation) assumptions were set for each CORESET, and this is used for the purpose of informing the characteristics of the analog beam direction in addition to the delay spread, Doppler spread, Doppler shift, and average delay, which are the characteristics assumed by the conventional QCL.

Figure 7 is a diagram to explain CORESET.

Referring to FIG. 7, CORESET may exist in various forms within one slot and within the carrier bandwidth, and in the time domain, CORESET may be composed of up to three OFDM symbols. Additionally, CORESET is defined as a multiple of 6 resource blocks from the frequency domain to the carrier bandwidth.

The first CORESET is directed through the MIB as part of the initial bandwidth part configuration to enable it to receive additional configuration and system information from the network. After establishing a connection with the base station, the terminal can receive and configure one or more CORESET information through RRC signaling.

In this specification, frequencies, frames, subframes, resources, resource blocks, regions, bands, subbands, control channels, data channels, synchronization signals, various reference signals, various signals, or various messages related to NR (New Radio) can be interpreted in a variety of meanings that may be used in the past or present, or may be used in the future.

NR(New Radio)

NR, which was recently developed in 3GPP, was designed to not only provide improved data transmission rates compared to LTE, but also to satisfy various QoS requirements required for each detailed and specific usage scenario. In particular, eMBB (enhancement Mobile BroadBand), mMTC (massive MTC), and URLLC (Ultra Reliable and Low Latency Communications) have been defined as representative usage scenarios of NR, and a flexible frame compared to LTE is a method to satisfy the requirements for each usage scenario. Structure design is required. Since each usage scenario has different requirements for data rates, latency, reliability, coverage, etc., different numerology ( It is designed to efficiently multiplex radio resource units based on (e.g. subcarrier spacing, subframe, TTI, etc.).

As a method for this, a method of supporting multiplexing based on TDM, FDM or TDM/FDM through one or multiple NR component carrier(s) for numerology with different subcarrier spacing values and scheduling unit in the time domain In configuring, discussions were held on ways to support more than one time unit. In this regard, in NR, a subframe has been defined as a type of time domain structure, and 14 OFDM symbols of normal CP overhead based on 15kHz SCS (Sub-Carrier Spacing), the same as LTE, are used as reference numerology to define the subframe duration. It was decided to define a single subframe duration consisting of . Accordingly, in NR, a subframe has a time duration of 1ms. However, unlike LTE, the subframe of NR is an absolute reference time duration, and slots and mini-slots can be defined as time units based on actual up/down link data scheduling. In this case, the number and y value of OFDM symbols constituting the corresponding slot were determined to have a value of y = 14 regardless of the SCS value in the case of normal CP.

Accordingly, any slot consists of 14 symbols, and depending on the transmission direction of the slot, all symbols are used for DL transmission, all symbols are used for UL transmission, or DL portion + (gap) + It can be used in the form of a UL portion.

In addition, a mini-slot consisting of fewer symbols than the slot is defined in any numerology (or SCS), and based on this, a short time-domain scheduling interval is set for transmitting and receiving up/down link data, or slot aggregation A long time-domain scheduling interval can be configured for up/downlink data transmission and reception. In particular, in the case of transmission and reception of latency-critical data such as URLLC, it is difficult to satisfy latency requirements when scheduling is done in slot units based on 1ms (14 symbols) defined in a numerology-based frame structure with a small SCS value such as 15kHz. Therefore, for this purpose, a mini-slot consisting of a smaller number of OFDM symbols than the corresponding slot can be defined and based on this, scheduling for latency critical data such as URLLC can be defined.

Or, as described above, by supporting numerologies with different SCS values within one NR Carrier by multiplexing them using the TDM and/or FDM method, based on the slot (or mini-slot) length defined for each numerology. A plan to schedule data according to latency requirements is also being considered. For example, as shown in Figure 8 below, when the SCS is 60kHz, the symbol length is reduced to about 1/4 compared to the SCS at 15kHz, so when one slot is configured with the same 14 OFDM symbols, the corresponding 15kHz-based slot The length becomes 1ms, while the 60kHz-based slot length is reduced to about 0.25ms.

As such, discussions are underway in NR on how to satisfy the requirements of URLLC and eMBB by defining different SCS or different TTI lengths.

Wider bandwidth operations

In the case of the existing LTE system, scalable bandwidth operation was supported for any LTC CC (Component Carrier). In other words, depending on the frequency deployment scenario, any LTE operator could configure a bandwidth of at least 1.4 MHz to a maximum of 20 MHz when configuring one LTE CC, and a normal LTE terminal could configure a bandwidth of 20 MHz for one LTE CC. Transmission and reception capabilities were supported.

However, in the case of NR, the design is made to enable support for NR terminals with different transmission and reception bandwidth capabilities through one wideband NR CC, and accordingly, arbitrary NR CCs are subdivided as shown in Figure 9 below. It is required to support flexible wider bandwidth operation through different bandwidth part configuration and activation for each terminal by configuring one or more bandwidth part(s) composed of bandwidth.

Specifically, in NR, one or more bandwidth parts can be configured through one serving cell configured from the terminal's perspective, and the terminal activates one DL bandwidth part and one UL bandwidth part in the serving cell to provide up/down link data. It is defined to be used for sending and receiving. In addition, when multiple serving cells are set in the terminal, that is, for terminals to which CA is applied, one DL bandwidth part and/or UL bandwidth part is activated for each serving cell to provide up/download using the radio resources of the corresponding serving cell. It is defined to be used for sending and receiving link data.

Specifically, an initial bandwidth part for the UE's initial access procedure is defined in any serving cell, one or more UE-specific bandwidth part(s) is configured through dedicated RRC signaling for each UE, and a fallback is provided for each UE. A default bandwidth part for operation can be defined.

However, in any serving cell, it can be defined to activate and use multiple DL and/or UL bandwidth parts at the same time depending on the capability and bandwidth part(s) configuration of the terminal. However, in NR rel-15, any terminal can activate any It is defined to activate and use only one DL bandwidth part and UL bandwidth part at a time.

In Network Energy Saving, an item of 3GPP NR Rel-18, several ways to maximize power efficiency are discussed, and among these, technologies for measuring and improving power efficiency in the wireless section are beginning to be discussed.

In order to maximize power efficiency by determining the MCS value, a method of transmitting using as low an MCS value as possible as radio resources allow has been used. In particular, in the uplink, the transmission power can be determined according to the indicated MCS value. Transmission power can be adjusted through an RRC parameter called deltaMCS. Specifically, the transmission power can be scaled in dB by the value obtained by multiplying BPRE (Bits per resource element, message bits including CRC by the number of assigned REs) determined by the set MCS value by 1.25. However, from the base station's perspective, in the conventional 3GPP NR, the UE transmission power was implicitly determined by having the UE determine the power of the PDSCH, etc., through power measurements such as DM-RS or PT-RS in order to set power according to the situation. .

Designing a system to accurately know the transmission power is a key factor in determining transmission and reception performance. However, the determination of the existing base station transmission power is performed arbitrarily by the base station, and the terminal operates in a way that determines the received power of the corresponding value through RS, which inevitably reduces the accuracy of the transmission power due to various noises. can be brought.

The present invention provides a method for a base station to determine transmission power for a specific terminal in an NR transmission and reception environment, and a procedure for allowing the UE to know this. In particular, it provides a method for the UE to specify the transmission power of the data area to be currently transmitted using the difference between the previously transmitted MCS and the current MCS and the CSI value reported by the UE in the corresponding channel.

The present invention broadly includes (1) a method for a base station to determine transmission power based on MCS, (2) a method for a base station to determine transmission power based on MCS difference, and (2) a method for a base station to determine transmission power based on CQI. Provides a method.

(1) Method for the base station to determine transmission power based on MCS: This method determines transmission power based on the MCS value to be used by the base station for data to be delivered to the UE. It can be broadly divided into a method for determining parameters, a method for determining whether the terminal is operating, and a method for communicating whether the base station is operating.

① Parameter determination method: For this purpose, the power adjustment parameter determined by the MCS index can be used. The power adjustment parameter can be applied by directly using the MCS value, or by calculating BPRE. This parameter can be used to determine the absolute transmit power of the base station.

② How to determine whether the terminal will operate: The terminal receives using only the estimate by RS without assuming the transmission power of the base station in cases where retransmission is made rather than the first transmission, or when the set MCS value is a specific value or above/below a specific value, etc. You can try .

③ Method of communicating whether the base station is operating: Whether or not the power adjustment operation will be performed can be communicated in advance to the RRC or DCI, and at this time, the terminal can additionally transmit an MCS value that will not assume the transmission power.

(2) How the base station determines the transmission power based on the MCS difference: This method determines the transmission power based on the MCS value that the base station used for the data just before delivered to the UE and the MCS value to be used for the newly delivered data. This is how to do it. It can be broadly divided into a method for determining parameters, a method for determining whether the terminal is operating, and a method for communicating whether the base station is operating.

① Parameter determination method: For this purpose, the power adjustment parameter determined by the difference between the two MCS indices can be used. This parameter may also be determined by the time difference between the slot in which the previous MCS was used, that is, the slot in which the previous data was transmitted, and the current slot. The power adjustment parameter can be applied by directly using the MCS value, or by calculating the difference between the previous BPRE and the current BPRE. This parameter can be used to determine the relative transmit power value compared to the base station's previous transmission.

② How to determine whether the terminal will operate: The terminal determines whether the time difference between two data transmissions exceeds a certain value, the terminal performs channel-related reporting, a retransmission is made instead of the first transmission, or the set MCS value is a specific value or a specific value. In cases such as above/below the value, reception can be attempted using only the estimate by RS without assuming the transmission power of the base station.

③ Method of communicating whether the base station is operating: Whether or not the power adjustment operation is performed can be transmitted in advance through RRC or DCI, and at this time, the terminal can additionally transmit a time difference value or MCS value that does not assume the transmission power. there is. Additionally, the operation can be made effective only within the BWP where the previous operation was performed.

(3) Method for the base station to determine transmission power based on CQI: This method determines transmission power based on the channel state information value last reported by the terminal and the MCS value to be used for newly transmitted data. It can be broadly divided into a method for determining parameters, a method for determining whether the terminal is operating, and a method for communicating whether the base station is operating.

① Parameter determination method: For this purpose, a power adjustment parameter determined by the difference between the MCS index to which the CQI value maps and the MCS index to be used can be used. The CQI value may be different for each subband to which resources are allocated, and in this case, the average of the values indicated by each CQI or the highest/or lowest CQI value may be used. This parameter can also be determined by the time difference between the slot where the terminal reporting was sent and the current slot. The power adjustment parameter can be applied by directly using the MCS value difference, or by calculating the difference between the spectrum efficiency determined by the CQI index and the current BPRE. This parameter can be used to determine the absolute or relative transmit power value of the base station.

② How to determine whether the terminal will operate: The terminal determines whether the time difference exceeds a certain value, when retransmission is made instead of the first transmission, when the terminal reports the CQI value as a specific value, or above/below a specific value, or when the set In cases where the MCS value is a specific value or above/below a specific value, the terminal may attempt reception using only the estimate by RS without assuming the transmission power of the base station.

③ Method of communicating whether the base station is operating: Whether or not the power adjustment operation will be performed can be communicated to the RRC in advance, and at this time, the terminal may additionally add a time difference value that will not assume the transmission power, or a CQI value or MCS value that will determine the operation performance. It can be delivered. Additionally, the operation may be effective only within the BWP where reporting was performed, or only within a subband, or only within a subband reporting the same CQI value.

The methods provided in the present invention may be applied independently or may be operated in combination in any form. For example, the base station can determine the transmission power based on the more recently used value of the last transmitted data and the last received terminal CQI, and can transmit which of the two to use through RRC or DCI. In addition, in the case of new terms, the terms used in the present invention are arbitrary names whose meanings are easy to understand, and the present invention can be applied even when other terms with the same meaning are actually used.

Through the method provided by the present invention, power-efficient transmission can be performed according to radio resource conditions in an NR transmission and reception environment.

FIG. 10 is a diagram showing the configuration of a base station 1000 according to another embodiment.

Referring to FIG. 10, a base station 1000 according to another embodiment includes a control unit 1010, a transmitter 1020, and a receiver 1030.

In the method for determining the base station transmission power necessary to perform the present invention described above, the control unit 1010 determines the overall base station ( 1000).

The transmitting unit 1020 and the receiving unit 1030 are used to transmit and receive signals, messages, and data necessary to perform the present invention described above with the terminal.

FIG. 11 is a diagram showing the configuration of a user terminal 1100 according to another embodiment.

Referring to FIG. 11, a user terminal 1100 according to another embodiment includes a receiving unit 1110, a control unit 1120, and a transmitting unit 1130.

The receiving unit 1110 receives downlink control information, data, and messages from the base station through the corresponding channel.

In addition, in the method for determining the base station transmission power necessary to perform the present invention described above, the control unit 1120 determines the transmission power for a specific terminal based on the MCS value to be applied to the data to be transmitted for the overall user. Controls the operation of the terminal 1100.

The transmitter 1130 transmits uplink control information, data, and messages to the base station through the corresponding channel.

The above-described embodiments may be supported by standard documents disclosed in at least one of the wireless access systems IEEE 802, 3GPP, and 3GPP2. That is, steps, configurations, and parts that are not described in the present embodiments to clearly reveal the technical idea may be supported by the above-mentioned standard documents. Additionally, all terms disclosed in this specification can be explained by the standard documents disclosed above.

The above-described embodiments can be implemented through various means. For example, the present embodiments may be implemented by hardware, firmware, software, or a combination thereof.

In the case of hardware implementation, the method according to the present embodiments uses one or more ASICs (Application Specific Integrated Circuits), DSPs (Digital Signal Processors), DSPDs (Digital Signal Processing Devices), PLDs (Programmable Logic Devices), and FPGAs. (Field Programmable Gate Arrays), processors, controllers, microcontrollers, or microprocessors.

In the case of implementation by firmware or software, the method according to the present embodiments may be implemented in the form of a device, procedure, or function that performs the functions or operations described above. Software code can be stored in a memory unit and run by a processor. The memory unit is located inside or outside the processor and can exchange data with the processor through various known means.

Additionally, terms such as "system", "processor", "controller", "component", "module", "interface", "model", or "unit" described above generally refer to computer-related entities hardware, hardware and software. It may refer to a combination of, software, or running software. By way of example, but not limited to, the foregoing components may be a process, processor, controller, control processor, object, thread of execution, program, and/or computer run by a processor. For example, both an application running on a controller or processor and the controller or processor can be a component. One or more components may reside within a process and/or thread of execution, and the components may be located on a single device (e.g., system, computing device, etc.) or distributed across two or more devices.

The above description is merely an illustrative explanation of the technical idea of the present disclosure, and those skilled in the art will be able to make various modifications and variations without departing from the essential characteristics of the present disclosure. In addition, the present embodiments are not intended to limit the technical idea of the present disclosure, but rather to explain it, so the scope of the present technical idea is not limited by these embodiments. The scope of protection of this disclosure should be interpreted in accordance with the claims below, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of rights of this disclosure.

Claims (1)

In a method for determining base station transmission power,
A method of determining transmission power for a specific terminal based on an MCS value to be applied to data to be transmitted for the terminal.