KR20210017777A - Apparatus and method of frequency-domain PRS muting in new radio - Google Patents

Abstract

In the present invention, more flexible PRS setting is possible by additionally defining frequency domain muting in addition to the existing time domain muting. The inter-cell PRS interference can be effectively controlled by newly applying frequency domain PRS muting according to the present proposal.

Description

[Apparatus and method of frequency-domain PRS muting in new radio}

The present invention proposes a method for setting a frequency domain downlink position positioning signal for 5G NR (New Radio). Since NR can set a larger system bandwidth than LTE, the PRS transmission band is divided into several smaller bandwidths. Therefore, by additionally defining frequency domain muting in addition to the existing time domain muting, a more flexible PRS setting becomes possible. By newly applying the frequency domain PRS muting according to this proposal, PRS interference between cells can be effectively controlled. .

In one aspect, the present embodiments can provide a more flexible PRS transmission setting by further defining frequency domain muting in addition to time domain muting.

1 is a diagram schematically illustrating a structure of an NR wireless communication system to which the present embodiment can be applied.
2 is a diagram for explaining a frame structure in an NR system to which this embodiment can be applied.
3 is a diagram illustrating a resource grid supported by a radio access technology to which the present embodiment can be applied.
4 is a diagram for explaining a bandwidth part supported by a wireless access technology to which the present embodiment can be applied.
5 is a diagram illustrating a synchronization signal block in a wireless access technology to which the present embodiment can be applied.
6 is a diagram for explaining a random access procedure in a radio access technology to which the present embodiment can be applied.
7 is a diagram for explaining CORESET.
8 is a diagram for explaining Example of symbol level alignment among different SCS.
9 is a diagram for explaining the LTE-A CSI-RS structure.
10 is a diagram for describing NR component CSI-RS RE patterns.
11 is a diagram for explaining NR CDM patterns.
12 is a diagram for explaining mapping of positioning reference signals (normal cyclic prefix).
13 is a conceptual diagram of OTDOA-based positioning.
14 is a diagram showing a PRS muting concept with muting pattern='1100'.
15 is a conceptual diagram of frequency domain NR PRS muting (in case of N _PRS = 4).
16 is a diagram showing a configuration of a base station according to another embodiment.
17 is a diagram showing a configuration of a user terminal according to another embodiment.

Hereinafter, some embodiments of the present disclosure will be described in detail with reference to exemplary drawings. In adding reference numerals to elements of each drawing, the same elements may have the same numerals as possible even if they are indicated on different drawings. In addition, in describing the embodiments, when 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 "include", "have", "consists of" and the like mentioned in the present specification are used, other parts may be added unless "only" is used. In the case of expressing the constituent elements in the singular, the case including plural may be included unless there is a specific explicit description.

In addition, in describing the constituent elements of the present disclosure, terms such as first, second, A, B, (a) and (b) may be used. These terms are only for distinguishing the component from other components, and the nature, order, order, or number of the component is not limited by the term.

In the description of the positional relationship of the 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" "It may be, but it should be understood that two or more components and other components may be further "interposed" to be "connected", "coupled" or "connected". Here, the other components may be included in one or more of two or more components "connected", "coupled" or "connected" to each other.

In the description of the temporal flow relationship related to the components, the operation method or the manufacturing method, for example, the temporal predecessor relationship such as "after", "after", "after", "before", etc. Alternatively, a case where a flow forward and backward relationship is described may also include a case that is not continuous unless "direct" or "direct" is used.

On the other hand, when a numerical value for a component or its corresponding information (e.g., level, etc.) is mentioned, the numerical value or its corresponding information is related to various factors (e.g., process factors, internal or external impacts, etc.) It can be interpreted as including an error range that may be caused by noise, etc.).

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

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

Meanwhile, a terminal in the present specification is a generic concept that refers to a device including a wireless communication module that performs communication with a base station in a wireless communication system, and is used in WCDMA, LTE, NR, HSPA, and IMT-2020 (5G or New Radio). It should be interpreted as a concept that includes all of the UE (User Equipment) of, as well as the MS (Mobile Station), UT (User Terminal), SS (Subscriber Station), and wireless device in GSM. In addition, the terminal may be a user's portable device such as a smart phone according to the usage type, and in the V2X communication system, it may mean a vehicle, a device including a wireless communication module in the vehicle, and the like. In addition, in the case of a machine type communication system, it may mean an MTC terminal, an M2M terminal, a URLLC terminal, etc. equipped with a communication module so that machine type communication is performed.

The base station or cell of the present specification refers to the end of communication with the terminal in terms of the network, and Node-B (Node-B), eNB (evolved Node-B), gNB (gNode-B), LPN (Low Power Node), Sector, Site, various types of antennas, BTS (Base Transceiver System), Access Point, Point (e.g., Transmit Point, Receiving Point, Transmitting Point), Relay Node ), a mega cell, a macro cell, a micro cell, a pico cell, a femto cell, a remote radio head (RRH), a radio unit (RU), and a small cell. Also, the cell may mean including a bandwidth part (BWP) in the frequency domain. For example, the serving cell may mean an activation BWP of the terminal.

In the various cells listed above, since there is a base station that controls one or more cells, the base station can be interpreted in two meanings. 1) In relation to the radio area, the device itself may provide a mega cell, a macro cell, a micro cell, a pico cell, a femto cell, and a small cell, or 2) the radio area itself may be indicated. In 1), all devices that are controlled by the same entity that provide a predetermined wireless area are controlled by the same entity, or all devices that interact to form a wireless area in collaboration are instructed to the base station. A point, a transmission/reception point, a transmission point, a reception point, etc. may be an embodiment of a base station according to the configuration method of the wireless area. In 2), it is also possible to instruct the base station to the radio region itself to receive or transmit a signal from the viewpoint of the user terminal or the viewpoint of a neighboring base station.

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

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

Uplink and downlink transmit and receive control information through a control channel such as Physical Downlink Control CHannel (PDCCH), Physical Uplink Control CHannel (PUCCH), and the like, and The same data channel is configured to transmit and receive data. Hereinafter, a situation in which signals are transmitted and received through channels such as PUCCH, PUSCH, PDCCH, and PDSCH is expressed in the form of'transmitting and receiving PUCCH, PUSCH, PDCCH and PDSCH'. do.

In order to clarify the description, hereinafter, the present technical idea is mainly described with a 3GPP LTE/LTE-A/NR (New RAT) communication system, but the present technical feature is not limited to the corresponding communication system.

3GPP develops 5G (5th-Generation) communication technology to meet the requirements of ITU-R's next-generation wireless access technology after research on 4G (4th-Generation) communication technology. Specifically, 3GPP develops a new NR communication technology separate from 4G communication technology and LTE-A pro, which has improved LTE-Advanced technology as a 5G communication technology to meet the requirements of ITU-R. Both LTE-A pro and NR refer to 5G communication technology. Hereinafter, 5G communication technology will be described centering on NR when a specific communication technology is not specified.

The operation scenario in NR defined various operation scenarios by adding considerations to satellites, automobiles, and new verticals from the existing 4G LTE scenario.In terms of service, eMBB (Enhanced Mobile Broadband) scenario, high terminal density, but wide It is deployed in the range and supports the mMTC (Massive Machine Communication) scenario that requires a low data rate and asynchronous connection, and the URLLC (Ultra Reliability and Low Latency) scenario that requires high responsiveness and reliability and supports high-speed mobility. .

In order to satisfy this scenario, NR discloses a wireless communication system to which a new waveform and frame structure technology, a low latency technology, a mmWave support technology, and a forward compatible provision technology are applied. In particular, in the NR system, various technological changes are proposed in terms of flexibility to provide forward compatibility. The main technical features of the NR will be described below with reference to the drawings.

<NR system general>

1 is a diagram schematically showing a structure of an NR system to which this embodiment can be applied.

1, the NR system is divided into 5GC (5G Core Network) and NR-RAN parts, and NG-RAN controls user plane (SDAP/PDCP/RLC/MAC/PHY) and UE (User Equipment). It is composed of gNB and ng-eNB that provide plane (RRC) protocol termination. The gNB or gNB and ng-eNB are interconnected through an Xn interface. The gNB and ng-eNB are each connected to 5GC through the NG interface. The 5GC may include an Access and Mobility Management Function (AMF) in charge of a control plane such as a terminal access and mobility control function, and a User Plane Function (UPF) in charge of a control function for user data. NR includes support for both frequency bands below 6GHz (FR1, Frequency Range 1) and frequencies above 6GHz (FR2, Frequency Range 2).

gNB means a base station that provides NR user plane and control plane protocol termination to a terminal, and ng-eNB means a base station that provides E-UTRA user plane and control plane protocol termination to a terminal. The base station described in the present specification should be understood in a sense encompassing gNB and ng-eNB, and may be used as a means to distinguish between gNB or ng-eNB as necessary.

<NR wave form, numer roller and frame structure>

In NR, a CP-OFDM waveform 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.

On the other hand, in NR, since the requirements for data rate, delay rate, and coverage are different for each of the three scenarios described above, it is necessary to efficiently satisfy the requirements for each scenario through a frequency band constituting an arbitrary NR system. . To this end, a technique for efficiently multiplexing a plurality of different numerology-based radio resources has been proposed.

Specifically, the NR transmission neuron is determined based on sub-carrier spacing and CP (cyclic prefix), and the value of μ is used as an exponential value of 2 based on 15khz as shown in Table 1 below. Is changed to.

μ Subcarrier spacing Cyclic prefix Supported for data Supported for synch 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, the NR neuron can be classified into 5 types according to the subcarrier interval. This is different from the fixed subcarrier spacing of 15khz of LTE, one of the 4G communication technologies. Specifically, subcarrier intervals used for data transmission in NR are 15, 30, 60, and 120khz, and subcarrier intervals used for synchronization signal transmission are 15, 30, 12, and 240khz. In addition, the extended CP is applied only to the 60khz subcarrier interval. On the other hand, a frame structure in NR is defined as a frame having a length of 10 ms consisting of 10 subframes having the same length of 1 ms. One frame can be divided into 5 ms half frames, and each half frame includes 5 subframes. In the case of the 15khz subcarrier interval, one subframe consists of 1 slot, and each slot consists of 14 OFDM symbols.

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

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

Meanwhile, NR defines a basic unit of scheduling as a slot, and introduces a mini-slot (or sub-slot or non-slot based schedule) in order to reduce the transmission delay of the radio section. If a wide subcarrier spacing is used, the length of one slot is shortened in inverse proportion, so that transmission delay in the radio section can be reduced. The mini-slot (or sub-slot) is for efficient support for the URLLC scenario, and scheduling is possible in units of 2, 4, or 7 symbols.

In addition, unlike LTE, NR defines uplink and downlink resource allocation as a symbol level within one slot. In order to reduce HARQ delay, a slot structure capable of transmitting HARQ ACK/NACK directly within a transmission slot has been defined, and this slot structure is named and 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, a common frame structure constituting an FDD or TDD frame is supported through a combination of various slots. For example, a slot structure in which all symbols of a slot are set to downlink, a slot structure in which all symbols are set to uplink, and a slot structure in which a downlink symbol and an uplink symbol are combined are supported. In addition, NR supports that data transmission is distributed and scheduled in one or more slots. Accordingly, the base station may inform the UE of whether the slot is a downlink slot, an uplink slot, or a flexible slot using a slot format indicator (SFI). The base station can indicate the slot format by indicating the index of the table configured through UE-specific RRC signaling using SFI, and dynamically indicates through Downlink Control Information (DCI) or statically or through RRC. It can also be quasi-static.

<NR physical resource>

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

The antenna port is defined so that a channel carrying a symbol on an antenna port can be inferred from a channel carrying another symbol on the same antenna port. When the large-scale property of a channel carrying a symbol on one antenna port can be inferred from a channel carrying a symbol on another antenna port, the two antenna ports are QC/QCL (quasi co-located or quasi co-location) relationship. Here, the wide-range characteristic includes at least one of delay spread, Doppler spread, frequency shift, average received power, and received timing.

3 is a diagram illustrating a resource grid supported by a radio access technology to which the present embodiment can be applied.

Referring to FIG. 3, since the NR supports a plurality of neurons in the same carrier, a resource grid may exist according to each neuron in the resource grid. In addition, the resource grid may exist according to an antenna port, a subcarrier interval, and a transmission direction.

A resource block consists of 12 subcarriers, and is defined only in the frequency domain. In addition, a resource element consists of one OFDM symbol and one subcarrier. Accordingly, as shown in FIG. 3, the size of one resource block may vary according to the subcarrier interval. In addition, NR defines “Point A” that serves as a common reference point for the resource block grid, a common resource block, and a virtual resource block.

4 is a diagram for explaining a bandwidth part supported by a wireless access technology to which the present 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 the NR, as shown in FIG. 4, a bandwidth part (BWP) can be designated within the carrier bandwidth and used by the terminal. In addition, the bandwidth part is associated with one neurology and is composed of a subset of consecutive common resource blocks, and can be dynamically activated over time. The UE is configured with up to four bandwidth parts, respectively, in uplink and downlink, and data is transmitted and received using the active bandwidth part at a given time.

In the case of a paired spectrum, uplink and downlink bandwidth parts are independently set, and in the case of an unpaired spectrum, unnecessary frequency re-tuning between downlink and uplink operations is prevented. For this purpose, the downlink and uplink bandwidth parts are set in pairs to share a center frequency.

<NR initial connection>

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

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

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

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

The terminal receives the SSB by monitoring the SSB in the time and frequency domain.

SSB can be transmitted up to 64 times in 5ms. A plurality of SSBs are transmitted in different transmission beams within 5 ms time, and the UE performs detection on the assumption that SSBs are transmitted every 20 ms period based on one specific beam used for transmission. The number of beams that can be used for SSB transmission within 5 ms time may increase as the frequency band increases. For example, under 3GHz, up to 4 SSB beams can be transmitted, in a frequency band of 3 to 6GHz, up to 8, and in a frequency band of 6GHz or higher, SSBs can be transmitted using up to 64 different beams.

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

Meanwhile, the SSB is not transmitted at the center frequency of the carrier bandwidth, unlike the conventional LTE SS. That is, the SSB may be transmitted even in a place other than the center of the system band, and a plurality of SSBs may be transmitted in the frequency domain when broadband operation is supported. Accordingly, the UE monitors the SSB by using a synchronization raster, which is a candidate frequency location for monitoring the SSB. The carrier raster and synchronization raster, which are information on the center frequency 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 to support fast SSB search of the terminal. I can.

The UE can acquire the MIB through the PBCH of the SSB. The MIB (Master Information Block) includes minimum information for the terminal to receive remaining system information (RMSI, Remaining Minimum System Information) broadcast by the network. In addition, PBCH is information about the location of the first DM-RS symbol in the time domain, information for the UE to monitor SIB1 (e.g., SIB1 neurology 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 in the carrier is transmitted through SIB1), and the like. Here, the SIB1 neurology 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, the neurology information of SIB1 may be applied to at least one of messages 1 to 4 for a random access procedure.

The aforementioned RMSI may mean System Information Block 1 (SIB1), and SIB1 is periodically broadcast (ex, 160ms) in a cell. SIB1 includes information necessary for the UE to perform an initial random access procedure, and is periodically transmitted through the PDSCH. In order for the UE to receive SIB1, it is necessary to receive newer roller information used for SIB1 transmission and CORESET (Control Resource Set) information used for SIB1 scheduling through the PBCH. The UE checks scheduling information for SIB1 using SI-RNTI in CORESET, and acquires SIB1 on the PDSCH according to the scheduling information. SIBs other than SIB1 may be periodically transmitted or may be transmitted according to the request of the terminal.

6 is a diagram for explaining a random access procedure in a radio access technology to which the present embodiment can be applied.

Referring to FIG. 6, when the cell search is completed, the UE transmits a random access preamble for random access to the base station. The random access preamble is transmitted through the PRACH. Specifically, the random access preamble is transmitted to the base station through a PRACH consisting of consecutive radio resources in a specific slot that is periodically repeated. In general, when a terminal initially accesses a cell, a contention-based random access procedure is performed, and when a random access is performed for beam failure recovery (BFR), a contention-free 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), a UL Grant (uplink radio resource), a temporary C-RNTI (Temporary Cell-Radio Network Temporary Identifier), and a 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 inform 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 UE to adjust uplink synchronization. The random access response may be indicated by a random access identifier on the PDCCH, that is, a Random Access-Radio Network Temporary Identifier (RA-RNTI).

Upon receiving a valid random access response, the terminal processes information included in the random access response and performs scheduled transmission to the base station. For example, the UE applies TAC and stores a temporary C-RNTI. Also, by using UL Grant, data stored in the buffer of the terminal or newly generated data is transmitted to the base station. In this case, information for identifying the terminal should be included.

Finally, the terminal receives a downlink message for resolving contention.

<NR CORESET>

The downlink control channel in NR is transmitted in CORESET (Control Resource Set) having 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, NR introduced the concept of CORESET to secure system flexibility. CORESET (Control Resource Set) means a time-frequency resource for a downlink control signal. The terminal may decode the control channel candidate using one or more search spaces in the CORESET time-frequency resource. A QCL (Quasi CoLocation) assumption for each CORESET is set, and this is used to inform the characteristics of the analog beam direction in addition to the delay spread, Doppler spread, Doppler shift, and average delay, which are characteristics assumed by conventional QCL.

7 is a diagram for explaining CORESET.

Referring to FIG. 7, CORESET may exist in various forms within a carrier bandwidth within one slot, and CORESET may consist of up to 3 OFDM symbols in the time domain. In addition, CORESET is defined as a multiple of 6 resource blocks up to the carrier bandwidth in the frequency domain.

The first CORESET is indicated through the MIB as part of the initial bandwidth part configuration so that additional configuration information and system information can be received from the network. After establishing the connection with the base station, the terminal may 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 as a meaning used in the past or present, or in various meanings used in the future.

[5G NR (New RAT)]

3GPP recently approved “Study on New Radio Access Technology”, a study item for research on next-generation/5G radio access technology, and based on this, RAN WG1 provides frame structure, channel coding & modulation for NR (New Radio) , waveform & multiple access scheme, etc. NR is required to be designed to satisfy not only an improved data transmission rate compared to LTE, but also various QoS requirements required for each detailed and detailed usage scenario. In particular, eMBB (enhancement Mobile BroadBand), mMTC (massive MTC), and URLLC (Ultra Reliable and Low Latency Communications) are defined as representative usage scenarios of NR. Structure design is required. Since each usage scenario has different requirements for data rates, latency, reliability, coverage, etc., it is a method to efficiently satisfy the requirements for each usage scenario through the frequency band constituting an arbitrary NR system. eg subcarrier spacing, subframe, TTI, etc.) There is a need for a method of efficiently multiplexing based radio resource units.

As a method for this, a method of multiplexing and supporting based on TDM, FDM or TDM/FDM through one or more NR component carrier(s) for numerology having different subcarrier spacing values, and scheduling units in the time domain. In the configuration, a discussion was made on how to support more than one time unit. In this regard, in NR, a subframe was defined as a kind of time domain structure, and 14 OFDM symbols of normal CP overhead based on 15kHz SCS (Sub-Carrier Spacing), which is the same as LTE, as a reference numerology for defining the corresponding subframe duration. It was decided to define a single subframe duration composed of. Accordingly, in NR, the subframe has a time duration of 1 ms. However, unlike LTE, a subframe of NR is an absolute reference time duration, and slots and mini-slots may be defined as time units that are the basis of actual uplink/downlink data scheduling. In this case, the number of OFDM symbols constituting the corresponding slot, y value is defined as y=7 and 14 for numerology having an SCS value of up to 60 kHz, and y=14 for numerology having an SCS value greater than 60 kHz. It was decided to have a value.

Accordingly, an arbitrary slot may be composed of 7 or 14 symbols, and according to the transmission direction of the corresponding slot, all symbols are used for DL transmission, or all symbols are used for UL transmission, or DL portion It can be used in the form of + (gap) + UL portion.

In addition, a mini-slot consisting of fewer symbols than the corresponding slot in an arbitrary numerology (or SCS) is defined, and a short time-domain scheduling interval for uplink/downlink data transmission/reception is set based on this, or slot aggregation A long time-domain scheduling interval for transmitting/receiving uplink/downlink data may be configured through. In particular, in the case of transmission and reception of latency critical data such as URLLC, when scheduling is performed in a slot unit based on 0.5ms (7 symbols) or 1ms (14 symbols) defined in a numerology-based frame structure with a small SCS value such as 15 kHz. For this purpose, since it may be difficult to satisfy the latency requirement, a mini-slot consisting of fewer OFDM symbols than the corresponding slot can be defined, and based on this, it can be defined to perform scheduling for latency critical data such as the corresponding URLLC.

Alternatively, as described above, by multiplexing and supporting numerology having different SCS values in one NR Carrier in a TDM and/or FDM method, based on the slot (or mini-slot) length defined for each numerology. Scheduling data according to latency requirements is also being considered. For example, as shown in FIG. 8 below, when the SCS is 60 kHz, the symbol length is reduced by about 1/4 compared to the SCS 15 kHz, so when one slot is configured with the same 7 OFDM symbols, the corresponding 15 kHz-based slot While the length becomes 0.5ms, the slot length based on 60kHz is reduced to about 0.125ms.

As described above, in NR, by defining different SCS or different TTI lengths, a discussion on a method of satisfying the requirements of URLLC and eMBB is in progress.

[LTE CSI-RS]

CSI provides a channel state for the network as a Channel State Indicator instead of channel estimation through the existing CRS. It is cell specific but is configured by the RRC signal of the UE. The CSI Reference signal was introduced in LTE Release 10. The CSI-RS estimates the demodulated RS and uses the UE to obtain channel state information.

In the existing LTE Rel-8/9, up to four cell-specific RSs (CRSs) were supported in a cell. However, as LTE-A (Rel-10) evolved, there was a need to expand CSI for cell reference signals supporting up to 8 layer transmission. Here, the antenna ports are allocated as 15-22 as shown in FIG. 9, and the transmission period and mapping are determined through RRC configuration for resource allocation. Table 2 defines the mapping method through CSI-RS configuration in normal CP.

[NR CSI-RS]

In NR, it was finally defined that the X-port CSI-RS is allocated to N consecutive/non-contiguous OFDM symbols. Here, the X-port, which is a CSI-RS port, has a maximum of 32 ports, and a symbol N to which a CSI-RS is allocated has a maximum of 4.

10 and 11 show the CSI-RS pattern and CDM pattern of NR.

Basically, the CSI-RS has a total of three component RE patterns as shown in FIG. 10. Hereinafter, Y and Z denote the length of the frequency axis and the length of the time axis of the CSI-RS RE pattern, respectively.

- (Y,Z)∈{(2,1),(2,2),(4,1)}

In addition, NR supports a total of three CDM patterns as shown in FIG. 11.

- FD-CDM2, CDM4(FD2,TD2), CDM8(FD2,TD4)

Referring to TS38.211, the spreading sequence actually allocated to each CDM pattern is as follows.

[LTE PRS]

In the existing LTE, higher-layer signaling can be transmitted through antenna port 6 as shown in FIG. 12 below. Through this, the terminal performs location positioning. Basically, PRS is transmitted to a predefined area through higher-layer signaling parameter setting.

-Δ _PRS : subframe offset

-T _PRS : Periodicity 160,320, 640, 1280 subframes

-N _PRS : Duration (=No. of consecutive subframes) 1,2,4,6 subframes

Basically, PRS uses Pseudo Rando Sequence, that is, Quasi-orthogonal feature sequence. That is, PRS sequences that overlap on the code can be separated using this orthogonal characteristic. Next, in the frequency domain, a total of 6 cells including 5 adjacent cells may be orthogonally allocated in the frequency domain using frequency reuse factor=6 in the frequency domain as shown in FIG. 12. At this time, the frequency domain location of the PRS RE basically uses PCI (physical cell ID) as an offset value.

Finally, if all the PRS transmission intervals are taken equally in the target cells in the time domain, collisions occur.Therefore, a muting interval can be set for each cell and adjusted so that PRS transmission can occur in an orthogonal time interval between specific cells or cell groups. .

The basic principle of positioning is estimating the received signal time difference (RSTD), that is, observed time difference of arrival (OTDOA). The basic principle is to estimate the location of the terminal by estimating the cross-region based on the time difference from at least three or more cells as shown in FIG. 13 below. In the PRS, PRS transmission information for up to 24X3 (3-sector) cells can be set to the UE through higher-layer signaling.

In addition, the UE must report the RSTD values estimated from each cell to the base station. The table below shows values used to report the time difference value estimated by the terminal.

Basically, an interval from -15391Ts to 15391Ts is defined as a reporting range, and a resolution of 1 Ts is up to -4096 Ts ≤ RSTD ≤ 4096 Ts. The resolution of the remaining section is 5 Ts.

Table 9.1.10.3-1: RSTD report mapping (TS36.133)

In addition, reporting on high resolution was also included in the standard, and the contents are shown in the table below. This value can be transmitted together with the previously estimated RSTD. In -2260 T _s ≤ RSTD ≤ 10451 T _s , reporting using RSTD_delta_0 and RSTD_delta_1 is possible, and 0000T _s ≤ RSTD ≤ 2259 T _s , 10452 T _s ≤ RSTD ≤ In the 12711 T _s interval, all values except RSTD_delta_1 can be used. For reference, 1 T _s means about 9.8m. The method calculated based on LTE subcarrier-spacing = 15 kHz is as follows.

- SCS=15kHz, reference OFDM symbol length = 66.7us

- Based on 2048FFT, 2048 samples in the time axis are generated (based on oversampling not applied).

-Length per 1 sample of time axis (=1T _s ) = 66.7us/2048samples in time * (3*108m/s) = 9.8m

[LTE PRS muting]

The PRS is transmitted with a constant power set for individual positioning occasions. However, the transmission power may be set to zero power at a specific point in time when PRS is transmitted, which is defined as PRS muting. For example, when the serving gNB performs muting and the UE receives the PRS signal, the probability that the PRS signal transmitted from the neighboring base station is more accurately detected by the UE increases.

The PRS muting configuration is set as a periodic muting sequence, and the period T _REP is positioning occasion 2,4,8,16,... , Can have a value of 1024. As shown in the table below, PRS muting has a length of 2,4,8,16,... , 1024 bits, and the sequence consists of '0' and '1'. If the PRS muting information is set to '0', the PRS is muted on the corresponding PRS positioning occasion. The first bit of the PRS muting sequence is applied from the first PRS positioning occasion after the time point after SFN = 0 of the reference cell.

Basically, the muting pattern can be applied within the period of T _REP × T _PRS > 10240 subframes. Here, T _PRS means a transmission period of the PRS. If it exceeds 10240 subframe, only the preceding n-bit is applied.

PRS-Info [TS 36.355-f40]

The IE PRS-Info provides the information related to the configuration of PRS in a cell.

14 below shows an example of a PRS muting pattern having T _REP of 4 Positioning occasions. The PRS muting bit string (= muting sequence) applied here is '1100', and the part marked in yellow indicates the PRS muting area, that is, the period in which the PRS is not transmitted.

Currently, NR PRS does not have a frequency domain muting method.

The present invention proposes a method for setting a frequency domain downlink position positioning signal for 5G NR. In the current NR, a larger system bandwidth can be set than that of LTE, so the PRS transmission band can be divided into several smaller bandwidths. Therefore, more flexible PRS transmission setting is possible by further defining frequency domain muting in addition to the existing time domain muting. PRS interference between cells can be effectively controlled by newly applying the frequency domain PRS muting according to this proposal.

Currently, NR Positioning was first discussed at the RAN1#94bis conference with Study Item'Study on NR positioning support'. The positioning use case suggested to most companies basically refers to the positioning use case and accuracy of TR 22.862. Briefly summarized in a table is as follows.

If NR requirements are summarized briefly, it can be seen that higher resolution should be provided than LTE and various use-cases should be supported. In addition, some scenarios require three-dimensional positioning.

Therefore, information on the vertical or horizontal direction must be additionally provided in addition to the existing OTDOA-based time difference. In addition, there is a need to provide single cell-based location positioning information based on the signal strength value and beam information.

The present invention proposes a frequency domain PRS muting method capable of increasing the detection accuracy of NR PRS based on the aforementioned various use-cases.

In the conventional PRS muting, the power actually set in the PRS transmission area of the corresponding eNB is set to 0 through the zero-power setting in the time domain. However, in NR, unlike the existing LTE, since the system bandwidth is relatively large and numerology can be flexibly set, it is possible to selectively improve the PRS reception accuracy of the terminal by applying muting in the frequency domain. In addition, more flexible PRS control may be possible by providing the gNB with trade-off autonomy of detection in consideration of the PRS sequence length and the bandwidth of the UE.

Scheme 1. In NR PRS transmission, set frequency domain muting.

Unlike conventional PRS muting, this proposal proposes frequency domain muting. This proposal can be used in parallel with the existing time domain muting method or separately set.

In the conventional PRS muting, when a muting sequence is applied in consecutive N _PRS consecutive subframes or consecutive slot intervals in the selected time domain, muting is performed to set all PRSs allocated to the entire band with zero-power. Here, N _PRS provided 1,2,4,6 consecutive subframe sections in the existing LTE. The setting value N _PRS may be used in the same manner in the NR PRS, but may be replaced with a slot that is a basic unit of NR instead of a subframe.

In this proposal, unlike the conventional method, frequency domain muting is applied to enable only a specific band to be turned on/off rather than collectively muting the entire system band allocated to the terminal.

Basically, through this proposal, unlike LTE, in NR, the system bandwidth can be set to 20MHz or higher, so the gNB has a flexible seat that can selectively turn on/off its own signal or the signal of the neighboring base station for the detection accuracy of the terminal Can provide.

For example, as shown in FIG. 15, it is assumed that the entire bandwidth is divided by half and a PRS sequence is allocated and transmitted only in the upper part. In this case, assuming that the interval N _PRS =4 in which the NR PRS is continuously transmitted, it can be seen that the PRS is not transmitted in the following four slot intervals. In this proposal, specific frequency domain PRS muting information is signaled to the terminal through this configuration, and the terminal attempts to detect only the band in which the PRS sequence is transmitted through the corresponding information.

Therefore, in this proposal, frequency domain muting information may be included in PRS_info (refer to existing TS 36.355), which is the PRS configuration information below. Here, the time domain setting information assumes a muting sequence length of 2,4,8,16, and a positioning occasion, and in actual setting, up to 1024*SFN beyond the corresponding range can be set. In addition,'prs-freq-MutingInfo', which is the frequency domain setting information, can be set in a bit string concept similar to the existing time domain muting. The definition of the muting bit setting information in the frequency domain can be performed in various ways.

As a result, by dividing the entire system bandwidth into N, one or several bands can be muted or transmitted simultaneously.

PRS-Info [TS 36.355-f40]

The IE PRS-Info provides the information related to the configuration of PRS in a cell.

Option 1-1. The frequency domain muting of the NR PRS can be set to different bands between PRS positioning occasions.

In FIG. 15 of Method 1 mentioned above, the concept of frequency muting within a PRS positioning occasion is described. The PRS positioning occasion period is defined as T _PRS and continuous slot/subframe N _PRS . In this proposal, different bands can be muted for each positioning occasion. Here, basically, only the first part of the frequency muting pattern at the point when SFN=0 is set, and can be implemented in a shifted form. It can also be implemented in a form of frequency hopping. Actual definition methods include increasing/decreasing order, staggered pattern, and predefined method.

Option 1-2. The frequency domain muting of the NR PRS can be applied in a different pattern even in a continuous slot/subframe period within a positioning occasion.

Basically, the PRS positioning occasion, which is a basic unit in which PRS is transmitted, consists of consecutive slots or subframes. In this case, frequency muting may perform muting by selecting different frequency bands even between slots of a corresponding region. For example, if the total bandwidth is divided into 3 bands,

-1 ^st slot → 1 ^st BW,

-2 ^nd slot → 2 ^nd BW,

-3 ^rd slot → 3 ^rd BW,

-4 ^th slot → 1 ^st BW

- ...

It can be set to.

Actual definition methods include increasing/decreasing order, staggered pattern, and predefined method.

Option 1-3. The frequency domain PRS Muting setting value is collectively determined.

In this proposal, it means that the frequency domain PRS muting pattern is configured according to a default value set in PRS-info signaling. That is, according to the set information, the terminal determines whether or not PRS frequency muting, a specific pattern, and the like.

Option 1-4. Some information of the frequency domain PRS Muting configuration values is implicitly determined based on the existing configuration information.

In this proposal, unlike'Scheme 1-3', basic information is used for PRS muting in the frequency domain. The following parameters can be considered regardless of the bandwidth size of the active BWP set to the terminal. For example, in defining a frequency muting pattern, an assisted information-based method may be applied, and there may be a cell ID, a slot index, and an SFN.

That is, the UE can know the starting point and pattern of frequency muting using the cell ID, SFN, etc. at the starting point of each SFN allocation. For example, if two frequency muting bands are set in cells with Cell ID=3, a simple modulo operation (3 mod 2 =1) is performed, and in the first positioning occasion, the first frequency muting is performed at 2 ^nd BW.

The present invention proposes a method for setting a frequency domain downlink position positioning signal for 5G NR. In the current NR, a larger system bandwidth can be set than that of LTE, so the PRS transmission band can be divided into several smaller bandwidths. Therefore, more flexible PRS transmission setting is possible by further defining frequency domain muting in addition to the existing time domain muting. PRS interference between cells can be effectively controlled by newly applying the frequency domain PRS muting according to this proposal.

16 is a diagram showing a configuration of a base station 1000 according to another embodiment.

Referring to FIG. 16, a base station 1000 according to another embodiment includes a control unit 1010, a transmission unit 1020, and a reception unit 1030.

The control unit 1010 controls the overall operation of the base station 1000 according to the additional definition and application of frequency domain muting in addition to the time domain muting required for carrying out the present invention.

The transmission unit 1020 and the reception unit 1030 are used to transmit and receive signals, messages, and data necessary for carrying out the above-described present invention with the terminal.

17 is a diagram showing a configuration of a user terminal 1100 according to another embodiment.

Referring to FIG. 17, a user terminal 1100 according to another embodiment includes a receiving unit 1110, a control unit 1120, and a transmitting unit 1130.

The receiver 1110 receives downlink control information, data, and a message from the base station through a corresponding channel.

In addition, the controller 1120 controls the overall operation of the user terminal 1100 according to the additional definition and application of frequency domain muting in addition to the time domain muting required for carrying out the present invention.

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

The above-described embodiments may be supported by standard documents disclosed in at least one of IEEE 802, 3GPP and 3GPP2 wireless access systems. That is, steps, configurations, and parts not described in order to clearly reveal the present technical idea among the embodiments may be supported by the aforementioned standard documents. In addition, all terms disclosed in the present specification can be described 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 implementation by hardware, the method according to the embodiments includes one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), and FPGAs. (Field Programmable Gate Arrays), a processor, a controller, a microcontroller, or a microprocessor.

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

In addition, terms such as "system", "processor", "controller", "component", "module", "interface", "model", or "unit" described above generally refer to computer-related entity hardware, hardware and software. It may mean a combination of, software or running software. For example, the above-described components may be, but are not limited to, a process driven by a processor, a processor, a controller, a control processor, an object, an execution thread, a program, and/or a computer. For example, both the controller or processor and the application running on the controller or processor can be components. One or more components may reside within a process and/or thread of execution, and the components may be located on one device (eg, a system, a computing device, etc.) or distributed across two or more devices.

The above description is merely illustrative of the technical idea of the present disclosure, and those of ordinary skill in the technical field to which the present disclosure pertains will be able to make various modifications and variations without departing from the essential characteristics of the technical idea. In addition, the present embodiments are not intended to limit the technical idea of the present disclosure, but to explain the technical idea, and thus the scope of the technical idea is not limited by these embodiments. The scope of protection of the present disclosure should be interpreted by the claims below, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present disclosure.

Claims (1)

In the method of processing a PRS signal,
A method of processing through more flexible PRS transmission settings by further defining frequency domain muting in addition to time domain muting.

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