KR20180090758A - Control method of wireless communication in cellular system based on beamfoaming - Google Patents

Abstract

The present disclosure relates to a communications technique for fusing a 5G communications system with an Internet-of-things (IoT) technique to support a higher data transmission rate than a 4G system, and a system thereof. The present disclosure can be applied to intelligent services (for example, smart home, smart building, smart city, smart car, connected car, healthcare, digital education, retail business, security- and safety-related services, and the like) on the basis of a 5G communications technique and an IoT-related technique. The present disclosure relates to a wireless network technique in a beamforming-based cellular system. According to one embodiment of the present specification, a method for compensating for phase noise of a terminal comprises the steps of: receiving information on an association relationship between at least one PTRS port and at least one DMRS port from a base station; confirming phase noise between the terminal and the base station on the basis of the information on the association relationship; and compensating for the phase noise on the basis of a confirmation result.

Description

TECHNICAL FIELD [0001] The present invention relates to a wireless communication control method in a beamforming-based cellular system,

The present invention relates to wireless network technology in a beamforming based cellular system.

Efforts are underway to develop an improved 5G or pre-5G communication system to meet the growing demand for wireless data traffic after commercialization of the 4G communication system. For this reason, a 5G communication system or a pre-5G communication system is called a system after a 4G network (Beyond 4G network) communication system or after a LTE system (Post LTE). To achieve a high data rate, 5G communication systems are being considered for implementation in very high frequency (mmWave) bands (e.g., 60 gigahertz (60GHz) bands). In order to mitigate the path loss of the radio wave in the very high frequency band and to increase the propagation distance of the radio wave, in the 5G communication system, beamforming, massive MIMO, full-dimension MIMO (FD-MIMO ), Array antennas, analog beam-forming, and large scale antenna technologies are being discussed. In order to improve the network of the system, the 5G communication system has developed an advanced small cell, an advanced small cell, a cloud radio access network (cloud RAN), an ultra-dense network, (D2D), a wireless backhaul, a moving network, cooperative communication, Coordinated Multi-Points (CoMP), and interference cancellation Have been developed. In addition, in the 5G system, the Advanced Coding Modulation (ACM) scheme, Hybrid FSK and QAM Modulation (FQAM) and Sliding Window Superposition Coding (SWSC), the advanced connection technology, Filter Bank Multi Carrier (FBMC) (non-orthogonal multiple access), and SCMA (sparse code multiple access).

On the other hand, the Internet is evolving into an Internet of Things (IoT) network in which information is exchanged between distributed components such as objects in a human-centered connection network where humans generate and consume information. IoE (Internet of Everything) technology, which combines IoT technology with big data processing technology through connection with cloud servers, is also emerging. In order to implement IoT, technology elements such as sensing technology, wired / wireless communication, network infrastructure, service interface technology and security technology are required. In recent years, sensor network, machine to machine , M2M), and MTC (Machine Type Communication). In the IoT environment, an intelligent IT (Internet Technology) service can be provided that collects and analyzes data generated from connected objects to create new value in human life. IoT is a field of smart home, smart building, smart city, smart car or connected car, smart grid, health care, smart home appliance, and advanced medical service through fusion of existing information technology . ≪ / RTI >

Accordingly, various attempts have been made to apply the 5G communication system to the IoT network. For example, technologies such as a sensor network, a machine to machine (M2M), and a machine type communication (MTC) are implemented by techniques such as beamforming, MIMO, and array antennas It is. The application of the cloud RAN as the big data processing technology described above is an example of the convergence of 5G technology and IoT technology.

The present invention provides a method for transmitting an RS in order to support uplink-based mobility.

In addition, the present invention provides a method and apparatus for operating phase tracking reference signal (PTRS) for phase noise compensation.

A method of compensating for phase noise of a UE in a wireless communication system according to an embodiment of the present invention includes calculating a correlation between at least one phase tracking reference signal (PTRS) port and at least one demodulation reference signal (DMRS) Receiving information from a base station; checking phase noise between the terminal and the base station based on the information about the association; and compensating for the phase noise based on the result of the checking .

The association information may indicate that the PTRS port is quasi-co-located with the DMRS port and may be received via higher layer signaling.

According to an embodiment, in a multi-transmission and reception point environment, a PTRS port may be used to estimate phase noise occurring in an oscillator corresponding to the PTRS port.

According to an embodiment, the information about the association is at least one of a delay spread, a doppler spread, a doppler shift, an average delay, and an average gain One can be included.

A method of compensating a phase noise of a base station in a wireless communication system according to an embodiment of the present invention includes determining a correlation between at least one phase tracking reference signal (PTRS) port and at least one demodulation reference signal (DMRS) And transmitting the information on the association relationship to the terminal so that the phase noise between the terminal and the base station is compensated based on the information on the association relationship.

The association information may indicate that the PTRS port is quasi-co-location with the DMRS port and may be transmitted through higher layer signaling.

According to an embodiment, in a multi-transmission and reception point environment, a PTRS port may be used to estimate phase noise occurring in an oscillator corresponding to the PTRS port.

According to an embodiment, the information about the association is at least one of a delay spread, a doppler spread, a doppler shift, an average delay, and an average gain One can be included.

A terminal that compensates for phase noise in a wireless communication system according to an embodiment of the present invention includes a transceiver and at least one phase tracking reference signal (PTRS) port and at least one DMRS a demodulation reference signal control unit for controlling the demodulation reference signal to receive from the base station information relating to the inter-port association, checking phase noise between the terminal and the base station based on the information about the association, For example.

A base station that compensates for phase noise in a wireless communication system according to an embodiment of the present invention includes a transmitter and receiver, and at least one phase tracking reference signal (PTRS) port and at least one DMRS a demodulation reference signal generating unit for generating information on an association between ports of the mobile station and transmitting the information on the association relation to the mobile station so that the phase noise between the mobile station and the base station is compensated based on the information about the association, . ≪ / RTI >

According to an embodiment of the present invention, by transmitting a reference signal (RS) capable of supporting mobility based on uplink (UL), power reduction of the UE and increase of paging resources efficiency .

Also, according to another embodiment of the present invention, phase noise can be efficiently compensated by defining a correlation (or mapping) between a phase tracking reference signal (PTRS) and another RS (reference signal).

FIG. 1 is a conceptual diagram illustrating uplink-based RRM measurement according to a first embodiment of the present invention.
2 is a diagram illustrating a PRACH configuration transmitted to an SIB according to the first embodiment of the present invention.
3 is a diagram illustrating a prach configIndex indicating a subframe index for PRACH transmission in the FDD according to the first embodiment of the present invention.
4 is a diagram illustrating a prach configIndex indicating a subframe index for PRACH transmission in the TDD according to the first embodiment of the present invention.
5 is a diagram illustrating a UE-dedicated RRC message for receiving a RACH in a common region according to the first embodiment of the present invention.
6 is a diagram illustrating a RACH preamble format in LTE according to the first embodiment of the present invention.
7 is a view illustrating an embodiment of a RACH configuration for performing UL beam measurement according to the first embodiment of the present invention.
FIG. 8 is a diagram illustrating an embodiment of a PRACH format according to the first embodiment of the present invention.
9 is a diagram illustrating an SRS configuration for periodic SRS transmission according to the first embodiment of the present invention.
10 is a diagram illustrating a first method of setting a sub-time unit due to a fourth method supporting RS for RRM measurement according to the first embodiment of the present invention.
11 is a diagram illustrating cell-specific SRS configuration for uplink RRM measurement according to the first embodiment of the present invention.
12 is a diagram illustrating a UE-specific SRS configuration for supporting uplink-based mobility according to the first embodiment of the present invention.
13 is a diagram illustrating a method for indicating a mechanism for UL beam measurement according to the first embodiment of the present invention.
FIG. 14 is a view showing an embodiment of cell-specific SRS configuration for UL beam measurement according to the first embodiment of the present invention.
15 is a view illustrating an embodiment of UE-specific SRS configuration for UL beam measurement according to the first embodiment of the present invention.
16 is a diagram illustrating an exemplary method of generating a UE specific SRS in a UE specific BW according to the first embodiment of the present invention.
FIG. 17 is a diagram illustrating a method of transmitting a partially overlapping SRS between UEs using a minimum unit SRS sequence generation method according to the first embodiment of the present invention.
18 is a graph showing the influence of phase noise according to the second embodiment of the present invention.
19 is a diagram illustrating the relationship between a PTRS port and a DMRS port in various TRP multi-panel environments according to a second embodiment of the present invention.
20 is a diagram illustrating a process of defining a relationship between a PTRS port and a DRMS port in a pre-defined method according to a second embodiment of the present invention.
FIG. 21 is a diagram illustrating a relationship between a PTRS port and a DMRS port through an indication signaling in a Multi-TRP environment according to a second embodiment of the present invention.
22 is a diagram illustrating an example of a process of resetting a PTRS port in a Multi-TRP environment according to a second embodiment of the present invention.
23 is a diagram illustrating a procedure for defining a PTRS port setting and a DMRS port relationship in a multi-panel and multi-oscillator environment of a UE according to a second embodiment of the present invention.
24 is a diagram illustrating a relationship between a CSI-RS port and a PTRS port according to a second embodiment of the present invention.
25 is a diagram illustrating a structure of a terminal according to embodiments of the present invention.
26 is a diagram illustrating a structure of a base station according to embodiments of the present invention.

In describing the embodiments of the present invention, descriptions of technologies which are well known in the art to which the present invention belongs and which are not directly related to the present invention are not described. This is for the sake of clarity of the present invention without omitting the unnecessary explanation.

For the same reason, some of the components in the drawings are exaggerated, omitted, or schematically illustrated. Also, the size of each component does not entirely reflect the actual size. In the drawings, the same or corresponding components are denoted by the same reference numerals.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

At this point, it will be appreciated that the combinations of blocks and flowchart illustrations in the process flow diagrams may be performed by computer program instructions. These computer program instructions may be loaded into a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus, so that those instructions, which are executed through a processor of a computer or other programmable data processing apparatus, Thereby creating means for performing functions. These computer program instructions may also be stored in a computer usable or computer readable memory capable of directing a computer or other programmable data processing apparatus to implement the functionality in a particular manner so that the computer usable or computer readable memory The instructions stored in the block diagram (s) are also capable of producing manufacturing items containing instruction means for performing the functions described in the flowchart block (s). Computer program instructions may also be stored on a computer or other programmable data processing equipment so that a series of operating steps may be performed on a computer or other programmable data processing equipment to create a computer- It is also possible for the instructions to perform the processing equipment to provide steps for executing the functions described in the flowchart block (s).

In addition, each block may represent a module, segment, or portion of code that includes one or more executable instructions for executing the specified logical function (s). It should also be noted that in some alternative implementations, the functions mentioned in the blocks may occur out of order. For example, two blocks shown in succession may actually be executed substantially concurrently, or the blocks may sometimes be performed in reverse order according to the corresponding function.

Herein, the term " part " used in the present embodiment means a hardware component such as software or an FPGA or an ASIC, and 'part' performs certain roles. However, 'part' is not meant to be limited to software or hardware. &Quot; to " may be configured to reside on an addressable storage medium and may be configured to play one or more processors. Thus, by way of example, 'parts' may refer to components such as software components, object-oriented software components, class components and task components, and processes, functions, , Subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. The functions provided in the components and components may be further combined with a smaller number of components and components or further components and components. In addition, the components and components may be implemented to play back one or more CPUs in a device or a secure multimedia card. Also, in an embodiment, 'to' may include one or more processors.

≪ Embodiment 1 >

In LTE, radio resource management (RRM) measurements for terminal mobility are performed on a downlink basis. Here, the base station transmits a reference signal (RS) for RRM measurement to the UE, and the UE measures the RRM of each cell using the RS, and reports the measured RRM to the BS. Meanwhile, the uplink-based RRM measurement process refers to a process in which the UE transmits the RS and the serving and neighboring BSs receive the RS differently from the downlink based on the RRM measurement.

The uplink-based RRM measurement is advantageous in comparison with the downlink-based RRM measurement.

First, the power reduction effect of the terminal can be expected. The downlink-based RRM measurement is performed by a base station transmitting a signal and a terminal measuring a signal quality of each base station. Here, the terminal must receive and process N adjacent signals. On the other hand, uplink-based RRM measurement requires only a process of generating and transmitting a signal, so that power consumption of the UE can be expected.

Second, the resource efficiency of the base station can be expected to increase. It is difficult for the base station to accurately grasp the position of the UE when only the downlink-based RRM measurement is considered. Therefore, to perform a page, the base station must perform a page in a large area. On the other hand, in the uplink-based RRM measurement process, since the base station receives the RS of the UE, the location of the UE can be grasped and it is advantageous that the page is not performed in a wide area such as the downlink.

To measure the uplink-based RRM, an RS for performing the uplink RRM is required. The RS that can perform the uplink-based RRM among the LTE-based RSs is as follows.

One. Random Access Channel (RACH)

2. UL DMRS (UL Demodulation RS)

3. UL SRS (UL Sounding RS)

FIG. 1 is a conceptual diagram for measuring uplink-based RRM according to the first embodiment of the present invention.

Assuming that there are N base stations in FIG. 1, all N base stations must be able to receive RSs transmitted from the terminals at the same time. The base station receiving the RS from the UE responds to the UE with the result of the RRM measurement after a predetermined processing time. At this time, in the uplink-based RRM, it is necessary to define a common area (UL common region) in which all the base stations can receive the RS like the downlink-based RRM.

FIG. 2 shows a RACH configuration transmitted to the SIB according to the first embodiment of the present invention.

The PRACH configuration shown in FIG. 2 is a cell specific signal. That is, the PRACH configuration refers to a signal received by all UEs in a cell in common. Among the signals shown in FIG. 2, prach_ConfigIndex is a parameter indicating a subframe in which a PRACH can be transmitted in a cell. In the case of FDD, the PRACH Configuration Index is shown in FIG. 3, and in the case of TDD, the PRACH Configuration Index is shown in FIG.

FIG. 3 is a diagram illustrating prach configIndex indicating a subframe index for PRACH transmission in the FDD according to the first embodiment of the present invention. FIG. 4 is a diagram illustrating a subframe index for PRACH transmission in the TDD according to the first embodiment of the present invention. ≪ / RTI >

As shown in FIG. 3 and FIG. 4, the RACH in the cell can be informed via the SIB by the subframe index that the base station can receive / transmit from the terminal. Basically, in order to minimize the collision probability, each cell allocates different values of prach configIndex so that the subframe index between adjacent cells does not overlap.

The first method for the BS to support the RS for measuring the uplink RRM of the UE is to allocate the prach configIndex informed in the SIB shown in FIG. 3 and FIG. 4 to the same value between adjacent cells. That is, by sharing the RACH transmit / receive subframe index between cells, all terminals can receive the PRACH transmitted by the UE. In addition, all parameters in the PRACH configuration must be shared between cells. However, PRACH for initial access and PRACH for UL RRM are not distinguished from each other and operate based on contention, and it is impossible for a base station to determine which terminal has transmitted a RACH for UL RRM only by RACH transmission. Also, there is a disadvantage that the collision probability of RACH for initial access increases.

The second method of supporting the RS for measurement of the uplink RRM of the UE in the base station can transmit the PRACH configuration shown in FIG. 2 to the UE using the RRC and share the message in the RRC with neighboring BSs. Here, a new RRC message must be defined in order to transmit the PRACH configuration to the UE through the RRC. The RACH configCommonRegion is defined to receive the RACH in the inter-cell common region shown in FIG.

A third method in which the BS supports the RS for measurement of the uplink RRM of the UE is a method of transmitting the PRACH configuration shown in FIG. 2 to the UE through the DCI. This DCI information should also be shared by all base stations. However, a very large number of bits is required for transmission to the DCI, which may appear as an overhead of the PDCCH information.

The uplink RRM measurement is performed in the CONNECTED state of the UE. Although the RACH configuration described above is defined without distinguishing between the CONNECTED mode and the IDLE mode, the RACH transmission in the CONNECTED state can be newly defined to reduce the power of the UE and increase the resource efficiency of the BS differently from the RACH transmission for the IDLE mode .

FIG. 5 is a diagram illustrating a UE-dedicated RRC message for receiving a RACH in the Common Region according to the first embodiment of the present invention. FIG. 6 is a diagram illustrating a RACH preamble format in LTE according to the first embodiment of the present invention. FIG.

 The RACH preamble consists of Tcp and Tseq, and five formats are defined according to cell coverage. Here, the Tcp interval is designed to cover twice the cell coverage considering the round trip delay between the BS and the MS. This is because the IDLE mode UE does not perform uplink synchronization with the BS.

As described above, since the RRM measurement is performed in the CONNECTED mode of the UE, it is not necessary to have the length of the CP which is twice as large as the cell coverage as shown in FIG. That is, the Tcp of the RACH for the CONNECTED mode has a length corresponding to half the length of the Tcp of the RACH for the IDLE mode. Therefore, the UE receiving the RACH configuration of FIG. 5 can transmit the RACH with the CP length corresponding to one-half of the Tcp for the IDLE mode RACH.

Another feature for CONNECTED RACH is that it must support a larger number of preamble IDs than the RACH in IDLE mode. In LTE, RACH for IDLE mode supports 64 preamble IDs per cell. These preamble IDs are assigned so that there is no collision between cells. However, as shown in FIG. 1, since all cells and TRPs receive RACHs transmitted in the common region, a preamble ID that can be shared between cells must be allocated. That is, as many as 64 preamble sets must be increased by at least D times the number of cells and TRPs received in the common region (e.g., D), the terminals in D cells can transmit RACH. That is, the prach-ConfigIndex in the PRACH-ConfigInfoCommd must provide 64 * number of cells.

The PRACH can also be used for UL beam measurement. That is, in a beamforming based system, the RACH can be transmitted for uplink beam measurement. Since the UL beam measurement can be UE-specific, UL beam measurement can be performed through a signaling method such as FIG. 6 or DCI. The UL beam measurement can be considered as a U-1 process for training both the transmission and reception beams of the BS and the UE, a U-2 process for training the reception beam of the BS, and a U-3 process for training the transmission beam of the UE have. Therefore, a 2-bit indicator indicating one of the U-1 through U-3 processes is additionally required.

7 is a view illustrating an embodiment of a RACH configuration for performing UL beam measurement according to the first embodiment of the present invention.

The prach_configBeam shown in FIG. 7 is information indicating the U-1, U-2, and U-3 described above, and may be added to the RRC message for the common region shown in FIG. That is, when all base stations / TRPs in the common region receive the RACH, they can share the RRC message and perform UL beam measurement of the UE. When the Prach_beam_procedure is 0, the UL beam measurement is not performed. If it is 1, the U-1 process can be performed. The Prach_preamble_format information is a parameter representing prach_format for multi-beam operation.

FIG. 8 is a diagram illustrating an embodiment of a PRACH format according to the first embodiment of the present invention.

As shown in FIG. 8, different prach formats can be used according to the value of prach_preamble_format. Max_prach_format is a parameter that indicates how many prach symbols are repeated in a given format when using a preamble format.

9 is a diagram illustrating an SRS configuration for periodic SRS transmission according to the first embodiment of the present invention.

The Sounding RS-UL-Config command shown in FIG. 9 is transmitted to the UE through the SIB in a cell specific configuration. Sounding RS-UL-ConfiDedicated represents a UE-specific configuration transmitted via RRC. The cell-specific configuration indicates the location of all subframes that can transmit SRS in the cell, and this can be allocated to the adjacent cells without overlapping through coordination. The UE-specific configuration is a configuration indicating the location of the SRS transmission subframe unique to the UE. The UE can transmit periodic SRSs at the indexes of subframes that coincide among the indexes of the detected subframes through these two configurations. The subcarrier spacing transmitted in the cell specific SRS configuration represents subcarrier spacing for SRS resource configuration.

10 is a diagram illustrating a first method of setting a sub-time unit due to a fourth method supporting RS for RRM measurement according to the first embodiment of the present invention.

Referring to FIG. 10, a UE may acknowledge a reference numerology and receive a cell-specific SRS configuration. The UE can confirm the subcarrier spacing of the cell-specific SRS setting and calculate the subcarrier spacing / reference numerology (L).

A fourth method of supporting RS for uplink RRM measurement of a UE by a base station is a method in which all base stations share a cell specific SRS configuration shown in FIG. Through this, all base stations can receive the SRS transmitted by the UE, but the probability of collision of the SRS increases, resulting in deterioration of performance of the uplink RRM measurement using the SRS. Here, the sub-time unit for shortening the beam measurement time can use the transmissionComb transmitted in the dedicated SRS configuration.

The fifth method of supporting the RS for measuring the uplink RRM of the UE is to newly define a cell-specific SRS configuration for uplink RRM measurement as shown in FIG. 10, and this configuration is shared by all the BSs. Also, the SRS for UL beam measurement can be transmitted in the subframe determined in cell specific SRS configuration. Here, in order to reduce the beam measurement time, a sub-time unit can be applied, which can be expressed as transmission comb or subcarrier spacing. That is, the SRS resource is determined by the numerology of the reference numerology / or data and the control channel, and the numerology of the SRS can be determined using the subcarrier spacing which is carried in the cell specific SRS configuration. The UE can determine the value of the subcarrier spacing / reference number (L) by using the reference numerology and the subcarrier spacing value delivered in the SRS configuration.

10 is a diagram illustrating a first method of setting a sub-time unit due to a fourth method supporting RS for RRM measurement. The base station may also calculate the sub-time as shown in FIG. 10 and perform beam sweeping in each sub-time unit. Unlike the method shown in FIG. 10, the sub-time unit can be set using the transmission comb value of the cell specific SRS configuration. In this case, a UE-specific SRS configuration that does not allow UE multiplexing can be configured for accurate beam measurements.

11 is a diagram illustrating cell-specific SRS configuration for uplink RRM measurement according to the first embodiment of the present invention.

The sixth method of supporting the RS for measuring the uplink RRM of the UE in the base station is to define a new cell-specific SRS configuration for the uplink RRM measurement as shown in FIG. 11 and add this configuration to all the BSs The UE-specific SRS configuration is newly defined, and this configuration is also shared by all base stations. Also, the SRS for UL beam measurement can be transmitted in the subframe determined in cell specific SRS configuration. Here, in order to reduce the beam measurement time, a sub-time unit can be applied, which can be expressed as transmission comb or subcarrier spacing. That is, the SRS resource is determined by the numerology of the reference numerology / or data and the control channel, and the numerology of the SRS can be determined using the subcarrier spacing which is carried in the cell specific SRS configuration. The UE can determine the value of the subcarrier spacing / reference number (L) by using the reference numerology and the subcarrier spacing value delivered in the SRS configuration. Also, the sub-time unit can be set using the transmission comb value of the cell specific SRS configuration. In this case, a UE-specific SRS configuration that does not allow UE multiplexing can be configured for accurate beam measurements.

12 is a diagram illustrating a UE-specific SRS configuration for supporting uplink-based mobility according to the first embodiment of the present invention.

Figure 12 includes a UE-specific configuration for periodic SRS transmissions and aperiodic SRS transmissions. It should be noted that the sharing of the neighboring cells of the configuration for RACH and SRS transmission described above is the same as setting the common region shown in FIG. Accordingly, neighbor BSs can receive the SRS / RACH transmitted by the UE and respond to the received SRS / RACH.

13 is a diagram illustrating a method for indicating a mechanism for UL beam measurement according to the first embodiment of the present invention.

SRS can be used for UL beam measurement as well as PRACH. That is, in a beamforming based system, SRS can be transmitted for uplink beam measurement. Since the UL beam measurement can be UE-specific, UL beam measurement can be performed through a signaling method such as FIG. 13 or DCI. The UL beam measurement includes a U-1 process of training both the transmission / reception beams of the base station and the UE, a U-2 process of training the reception beam of the base station (e.g., an indicator of '01' , And a U-3 process (e.g., an indicator '11') for training the terminal's transmission beam can be considered. Therefore, a 2-bit indicator indicating one of the U-1 through U-3 processes is additionally required. The other mode may indicate that the SRS is used for CSI acquisition purposes (e.g., the indicator is '00').

In the case of the PRACH described above, a format capable of transmitting a plurality of RACH preambles is supported to conform to the UL beam measurement. On the other hand, the SRS is being transmitted to the last symbol of the subframe. Also, since the shortest period is 2ms, it is not suitable to support UL beam measurement through the current SRS configuration. Therefore, signaling is required to transmit multiple SRSs in a subframe capable of SRS transmission. Such signaling may be provided in a DCI, MAC CE or RRC configuration. The following cases can be considered for the multiple transmission of SRS.

One. Allows SRS transmission of one or more PUSCH sybmol so that it can transmit / receive while modifying the beam in SRS transmittable subframe (resource)

2. SRS Assigns a number of subframes (resources) so that the beam can be transmitted / received based on the subframe (resource) that can be transmitted.

3. Reduces the SRS transmission time to transmit multiple SRSs within an OFDM symbol

FIG. 14 is a view showing an embodiment of cell-specific SRS configuration for UL beam measurement according to the first embodiment of the present invention.

In order to transmit the SRS using the PUSCH symbol, which is the first method for transmitting a plurality of SRSs, the following cell-specific SRS configuration should be provided. Here, srs-MaxTrans means a plurality of SRS transmissions. That is, when a subframe index for transmitting SRS is set through cell-specific / ue-specific configuration, SRS is transmitted from the corresponding subframe to srs-MaxTrans. A terminal that does not transmit SRS in the corresponding subframe can perform PUSCH transmission by referring to srs-MaxTrans. It should be noted that the parameter srs-MaxTrans can be transmitted in a UE-specific SRS configuration. In this case, a terminal that does not transmit SRS should know how many symbols are allocated to the PUSCH in the corresponding subframe through the DCI.

In order to allocate consecutive subframes, which is the second method for transmitting a plurality of SRSs, a cell-specific SRS configuration as shown in FIG. 10 must be provided. Here, srs-MaxTrans means a plurality of SRS transmissions, which means the number of consecutive subframes, not the PUSCH symbols in one subframe, as described above. That is, when a subframe index for transmitting SRS is set through a cell-specific / ue-specific configuration, SRS is transmitted during a subframe of srs-MaxTrans from the corresponding subframe. A terminal that does not transmit SRS in the corresponding subframe can perform PUSCH transmission by referring to srs-MaxTrans. The parameter srs-MaxTrans can also be transmitted in a UE-specific SRS configuration. In this case, a terminal that does not transmit the SRS should recognize whether the SRS is being transmitted in the corresponding subframe through the DCI.

15 is a view illustrating an embodiment of UE-specific SRS configuration for UL beam measurement according to the first embodiment of the present invention.

A cell-specific SRS configuration as shown in FIG. 15 must be provided in order to transmit a plurality of SRSs in a symbol, which is a third method for transmitting a plurality of SRSs.

Here, the srs-type has values of 0 and 1, and according to the srs-type, it is possible to determine whether SRS is transmitted using consecutive OFDM symbols in a subframe or whether SRS transmission is consecutively performed in an adjacent subframe . srs-MaxTrans means multiple SRS transmissions, which means the number of PUSCH symbols or consecutive subframes in one subframe depending on the srs-type. SRS-SCS denotes a subcarrier spacing value for SRS transmission, and the effect of transmitting a plurality of SRSs in one OFDM symbol may be exhibited.

The following describes how to assign an SRS sequence. The reference signal in LTE is determined by the number of RBs to which RS is assigned. For example, RS and 4RB allocated to 100RB generate different sequences. Therefore, when transmitting SRSs between UEs, terminals transmitting SRS having different lengths can not share the same time / frequency resources. Therefore, there is a limitation in SRS transmission resource management. The SRS sequence is different depending on the allocated band, and another sequence may be generated according to the cyclic shift and transmission comb values configured for each UE.

In order to operate SRS resources efficiently, it is necessary to share partial or total resources between different terminals. The SRS sequence design method for sharing partial or total resources between different terminals is a method for generating SRS sequence by block. For example, if the minimum unit RB for the SRS transmission is N, the SRS sequence is generated for the N RB length.

Figure 16 is a diagram illustrating how a UE-specific SRS is generated within a UE-specific BW; In FIG. 16, the 2N RB represents the SRS bandwidth (BW) allocated by a specific UE. Here, in the existing LTE, an SRS sequence for a 2N RB length is generated. The base station can inform the UE in a cell specific or UE-specific SRS configuration how many SRB sequences are to be generated in units of RBs. If it is informed through the cell specific SRS configuration, all UEs can make an SRS sequence of the same length, and if UE-specific SRS configuration is informed, it is advantageous to use resources more efficiently. However, allocation is complicated.

However, in the same manner as LTE, it is difficult to transmit SRS because it is partially overlapped between UEs. This is because orthogonality between sequences is not established when SRS transmission is partially overlapped.

FIG. 17 is a diagram illustrating a method of transmitting a partially overlapping SRS between UEs using a minimum unit SRS sequence generation method according to the first embodiment of the present invention.

16, since the orthogonality of the sequence can be satisfied within the RB of the minimum unit, the SRS can be partially overlapped and transmitted as shown in FIG.

Here, the sequence generation method may include the index of the RB in order that the minimum unit of SRS transmission satisfies the orthononality between sequences in the corresponding band. That is, the SRS in the band including the i-th RB can generate the SRS including the i-th RB index. In this case, the inter-UE SRSs within the RB can satisfy orthogonality with each other. That is, when generating the SRS sequence, it can include the RB index as well as the length of the RB. However, since a cyclic shift value usable due to a short sequence may be reduced compared with LTE, a method of generating various SRS sequence IDs can be considered.

In the existing LTE, all UEs in the cell use the same SRS sequence ID. That is, transmission comb and cyclic shift are used for UE multipelxing. Here, the UE can increase the multiplexing gain using the UE-specific SRS ID, and the UE-specific SRS ID can be delivered to the UE through the SRS configuration. Also, it can transmit SRS ID through DCI / MAC CE for dynamic scheduling.

≪ Embodiment 2 >

In order to secure an efficient frequency band, it is expected to use a high frequency band such as mmWave in the next generation communication environment. In this high frequency band, the signal attenuation due to the influence of the phase noise largely occurs. Phase noise is an effect caused by the incompleteness of the oscillator. This is caused by the common phase error (CPE) caused by the phase noise in the communication environment using the higher order modulation scheme (ex. 16QAM, 64QAM, 256QAM) The signal restoration capability is rapidly deteriorated due to the signal attenuation.

18 is a graph showing the influence of phase noise according to the second embodiment of the present invention. Even in the ideal channel environment, the phase of the constellation changes due to the influence of the phase noise, and it is confirmed that the ICI occurs. Therefore, a new reference signal is needed to estimate the phase noise to compensate for this phase noise. This is called PTRS.

The number of ports in PTRS is determined by the phase noise source, which is related to the number of oscillators. In other words, since the phase noise of each oscillator may occur differently, the number of PTRS ports corresponding to the corresponding number of phase noise is required to measure each phase noise. The relationship between the PTRS port and the DMRS port may vary depending on the structure of the transmitter.

19 is a diagram illustrating a relationship between a PTRS port and a DMRS port in various TRP multi-panel environments according to a second embodiment of the present invention.

Case 1 is an environment in which two panels (panel) use one oscillator and in case 2, two panels (panel) use two oscillators. That is, in case 1, since there is one phase noise source, one PTRS port can be used to compensate for phase noise. In case 2, however, two independent PTRS ports are needed to measure and compensate for independent phase noise for each panel. In this case, ambiguity occurs in relation to the DMRS port transmitted through each panel.

Specifically, DMRS port 2 and DMRS port 3 of case 1 use PTRS port 0, but DMRS port 2 of case 2 and PTRS port 1 of DMRS port 3 should be used. Therefore, a method of properly defining the relationship between the DMRS port and the PTRS port is needed. The technique proposed in the present invention considers operation without restriction to a specific downlink (DL) and uplink (UL) environments.

There are two methods for defining the relationship between the PTRS port and the DMRS port.

The first is to define the relationship between the pre-defined PTRS port and the DMRS port, and periodically follow the promised relationship rules without additional indication signaling. For example, if multiple oscillators are used, the phase noise can be compensated by calculating the offset value that can estimate the phase noise of the other oscillator based on the phase noise of the reference oscillator and informing related information. In this case, the PTRS port requires only one port to measure the phase noise of the reference oscillator. Each DMRS port newly estimates and compensates for phase noise by reflecting the corresponding offset value.

20 is a diagram illustrating a process of defining a relationship between a PTRS port and a DRMS port by a pre-defined method according to a second embodiment of the present invention

Referring to FIG. 20, the process of defining the relationship between the PTRS port and the DRMS port includes a reference phase noise estimation (S2010), a phase noise offset estimation for each oscillator S2020 ). In the case where a multi-PTRS port is applied, the above process may include a predefined mapping method (S2030) between the PTRS port and the DMRS port and / or a predefined mapping method (S2040) using the RRC / capability / MIB have.

Reference Shares information between transceivers through signaling such as RRC, capability information, MIB, SIB offset value measured based on oscillator. It is possible to decide which signal to transmit information according to the time during which the relationship between the DMRS port and the PTRS port is maintained constant. In addition, when a plurality of PTRS ports are utilized without using an offset, the relationship between a plurality of PTRS ports and a DMRS port can be pre-defined and the corresponding information can be signaled. This is in a trade-off relationship between PTRS overhead and phase noise estimation and compensation.

The second method is to periodically specify the relationship between the PTRS port and the DMRS port through indication signaling. This can be effectively used when the relationship between the DMRS port and the PTRS port changes dynamically. Quasis-co-location (QCL) signaling can be utilized as an embodiment of indication signaling. QCL can assume a QCL if the large-scale properties of the two ports are similar. Therefore, the relationship between the DMRS port and the PTRS port can be defined dynamically through QCL assumption and signaling between the DMRS port and the corresponding PTRS port. This indication signaling method can be used effectively in a single TRP transmission with different oscillator and panel configurations, and can be useful in multi-TRP environments.

FIG. 21 is a diagram illustrating a relationship between a PTRS port and a DMRS port in a multi-TRP environment according to a second embodiment of the present invention. TRP1's panel1 and panel2 use one oscillator and panel1 and panel2 of TRP2 use two separate oscillators. In total, three PTRS ports are required to estimate the phase noise of each oscillator. Therefore, the re-configuration of the PTRS port must be performed, and the relation between the PTRS port and the DMRS port may vary according to the transmission technique used in the multi-TRP environment. Therefore, the relationship between the ports must be defined through indication signaling.

22 is a diagram illustrating an example of a process of resetting a PTRS port in a Multi-TRP environment according to a second embodiment of the present invention.

Referring to FIG. 22, the reconfiguration process of the PTRS port includes a multi-TRP operation confirmation S2210, a PTRS port reset S2220, a PTRS port and a DMRS port mapping S2230, a transmission scheme change S2240, And an indicator signaling method (S2250).

As shown in FIG. 22, the number of DMRS ports and the number of PTRS ports can be set differently according to utilization of joint transmission (same CW / different CW) and dynamic point selection, which is a transmission technique used in a multi-TRP environment. The relationship between the port and the PTRS port must be specified.

23 is a diagram illustrating a procedure for defining a PTRS port setting and a DMRS port relationship in a multi-panel and multi-oscillator environment of a UE according to a second embodiment of the present invention.

Referring to FIG. 23, the process of defining the PTRS port setting and the DMRS port relationship includes DMRS port and PTRS port mapping (S2310), phase noise estimation using PTRS (S2320) (DMRS, S2330) using DMRS, phase noise compensation (DMRS, S2340) using DMRS, channel estimation compensation in PTRS (S2350) using PTRS, (Enhanced data detection, S2360).

FIG. 23 shows a series of processes for performing phase noise compensation and channel estimation through the relationship between the PTRS port and the DMRS port. By using PTRS to estimate phase noise and correcting it before channel estimation using DMRS, more accurate channel estimation can be achieved. In contrast, when a plurality of DMRS ports are mapped to one PTRS port, more accurate phase noise tracking can be performed by performing phase noise estimation using CPEs measured at a plurality of DMRS ports. Ultimately, it is possible to maximize signal restoration performance by repeating this series of processes.

It is necessary to define the relationship between the PTRS port and the CSI-RS ports, similar to the one discussed above in relation to defining the relationship between the PTRS port and the DMRS ports. When estimating the channel quality through the CSI-RS, the CQI measurement may cause an error in the CQI measurement because it reflects a different value from the actual channel quality due to the phase noise. Therefore, before acquiring CQI information through CSI-RS, phase noise should be estimated through PTRS and proper CPE compensation should be performed. Similar to the ambiguity between the DMRS port and the PTRS port described above, ambiguity may occur between the CSI-RS resource and the PTRS port depending on the environment in which the CSI-RS resource is assigned to each panel. Therefore, a mapping method is needed to resolve the ambiguity between the PTRS port and the CSI-RS resource.

24 is a diagram illustrating a relationship between a CSI-RS port and a PTRS port according to a second embodiment of the present invention.

FIG. 24 is a diagram illustrating a relationship between a CSI-RS resource allocation and a PTRS port according to a panel. Each panel uses a separate CSI-RS resource, panel 1 and panel 2 share one oscillator, and panel 3 and panel 4 use separate oscillators. In this case, there are three PTRS ports in order to estimate and compensate the phase noise occurring in each oscillator, and thus the relationship between the CSI-RS resource and the PTRS port must be defined. As a method of defining the relationship between the CSI-RS resource and the PTRS port, both a pre-defined method similar to the method of defining the relationship between the DMRS port and the PTRS port, and an indication signaling method can be used. Specifically, if the CSI-RS resource setting of the panel is maintained constant, it can be set to pre-defined and operated without periodic signaling. In addition, when CSI-RS resource setting is performed dynamically, it can be operated by using indication signaling. CQI measurement and phase noise enhancement can be obtained through QCL assumption and signaling between CSI-RS resource and PTRS port similar to the case of using QCL assumption and signaling between DMRS port and PTRS port. Also, the relationship between the PTRS port and the CSI-RS resource in the multi-TRP environment can be similar to the operation of the PTRS port and the DMRS port described above. That is, the PTRS port is re-configured according to the multi-TRP environment and transmission technology, and the relationship with the CSI-RS resources in the multi-TRP environment is defined.

A concrete method for defining the relationship between the PTRS port and the DMRS / CSI-RS using the QCL assumption and indication described above may be as follows. The QCL assumption parameters for the PTRS port and the DMRS / CSI-RS are additionally set in the higher layer signaling set of the RRC, and the parameter set is set to one of the parameter sets through the PQI (PDSCH RE mapping and quasi-co- To the user. The large-scale parameter used in the QCL assumption can be specified as one or more parameters of delay spread, doppler spread, doppler shift, average delay and average gain. The receiver obtains the relationship between the PTRS port and the DMRS / CSI-RS phase noise compensation, channel estimation, and CQI measurement.

25 is a diagram illustrating a structure of a terminal according to embodiments of the present invention.

25, the terminal may include a transmission / reception unit 2510, a control unit 2520, and a storage unit 2530. In the present invention, the control unit may be defined as a circuit or an application specific integrated circuit or at least one processor.

The transmission / reception unit 2510 can transmit and receive signals with other network entities. The transmission / reception unit 2510 can receive system information from, for example, a base station and can receive a synchronization signal or a reference signal.

The controller 2520 can control the overall operation of the terminal according to the first and second embodiments proposed by the present invention. For example, the controller 2520 may control the signal flow between each block to perform the operation according to the flowcharts described above.

Specifically, the controller 2520 controls to receive from the base station information related to the association between at least one phase tracking reference signal (PTRS) port and at least one demodulation reference signal (DMRS) port, And the phase noise between the base station and the base station is compensated based on the result of the check.

At this time, the information on the association indicates that the PTRS port is quasi-co-located with the DMRS port and can be received through higher layer signaling.

According to an embodiment, in a multi-transmission and reception point environment, a PTRS port may be used to estimate phase noise occurring in an oscillator corresponding to the PTRS port.

According to an embodiment, the information about the association is at least one of a delay spread, a doppler spread, a doppler shift, an average delay, and an average gain One can be included.

The storage unit 2530 may store at least one of the information transmitted / received through the transmission / reception unit 2510 and the information generated through the control unit 2520. For example, the storage unit 2530 may store information about a relationship between at least one phase tracking reference signal (PTRS) port and at least one demodulation reference signal (DMRS) port.

26 is a diagram illustrating a structure of a base station according to embodiments of the present invention.

Referring to FIG. 26, the base station may include a transmission / reception unit 2610, a control unit 2620, and a storage unit 2630. In the present invention, the control unit may be defined as a circuit or an application specific integrated circuit or at least one processor.

Transceiver 2610 can send and receive signals with other network entities. The transmission / reception unit 2610 may transmit system information to the terminal, for example, and may transmit a synchronization signal or a reference signal.

The controller 2620 can control the overall operation of the base station according to the first and second embodiments of the present invention. For example, the controller 2620 may control the signal flow between each block to perform the operations according to the flowcharts described above.

Specifically, the controller 2620 generates information about at least one phase tracking reference signal (PTRS) port and at least one demodulation reference signal (DMRS) port association information, and based on the information about the association relationship, And may transmit information on the association to the terminal so that the phase noise between the terminal and the base station is compensated.

At this time, the information on the association indicates that the PTRS port is quasi-co-located with the DMRS port and can be transmitted through higher layer signaling.

According to an embodiment, in a multi-transmission and reception point environment, a PTRS port may be used to estimate phase noise occurring in an oscillator corresponding to the PTRS port.

According to an embodiment, the information about the association is at least one of a delay spread, a Doppler spread, a Doppler shift, an average delay, and an average gain One can be included.

The storage unit 2630 may store at least one of information transmitted and received through the transmission / reception unit 2610 and information generated through the control unit 2520. For example, the storage unit 2630 may store at least one information related to a relationship between a phase tracking reference signal (PTRS) port and at least one demodulation reference signal (DMRS) port.

It should be noted that the embodiments of the present invention disclosed in the present specification and drawings are only illustrative of the present invention in order to facilitate the understanding of the present invention and are not intended to limit the scope of the present invention. That is, it will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible. Further, each of the above embodiments can be combined with each other as needed. For example, the base station and the terminal can be operated by combining the first and second embodiments of the present invention. Also, although the above embodiments are presented on the basis of the LTE / LTE-A system, other systems based on the technical idea of the above embodiment may be applicable to other systems such as 5G and NR systems.

Claims (20)

A method of compensating phase noise of a terminal in a wireless communication system,
Receiving from a base station information relating to at least one phase tracking reference signal (PTRS) port and at least one demodulation reference signal (DMRS) port;
Checking phase noise between the subscriber station and the base station based on information about the association; And
And compensating for the phase noise based on the verification result. 2. The method according to claim 1,
And the PTRS port is quasi-co-located with the DMRS port. 2. The method of claim 1, wherein the information about the association is received via higher layer signaling. 2. The method of claim 1, wherein a PTRS port in a multi-transmission and reception point environment is used to estimate phase noise occurring in an oscillator corresponding to the PTRS port. 2. The method according to claim 1,
Characterized in that it comprises at least one of a delay spread, a doppler spread, a doppler shift, an average delay, and an average gain. A method for compensating phase noise of a base station in a wireless communication system,
Generating information relating to at least one phase tracking reference signal (PTRS) port and at least one demodulation reference signal (PDRS) port; And
And transmitting information on the association to the terminal so that phase noise between the terminal and the base station is compensated based on the information on the association. 7. The method according to claim 6,
And the PTRS port is quasi-co-located with the DMRS port. 7. The method of claim 6, wherein the information about the association is sent via higher layer signaling. 7. The method of claim 6, wherein in a multi-transmission and reception point environment, a PTRS port is used to estimate phase noise occurring in an oscillator corresponding to the PTRS port. 7. The method according to claim 6,
Characterized in that it comprises at least one of a delay spread, a doppler spread, a doppler shift, an average delay, and an average gain. A terminal for compensating for phase noise in a wireless communication system,
A transmission / reception unit; And
And controls to receive from the base station information related to the association between at least one phase tracking reference signal (PTRS) port and at least one demodulation reference signal (DMRS) port, And a controller for checking the phase noise between the subscriber station and the base station based on the result of the checking and compensating the phase noise based on the checking result. 12. The method according to claim 11,
Wherein the PTRS port indicates quasi-co-location with the DMRS port. 12. The terminal of claim 11, wherein the information about the association is received through higher layer signaling. 12. The terminal of claim 11, wherein in a multi-transmission and reception point environment, a PTRS port is used for estimating phase noise occurring in an oscillator corresponding to the PTRS port. 12. The method according to claim 11,
Wherein the at least one terminal comprises at least one of a delay spread, a doppler spread, a doppler shift, an average delay, and an average gain. A base station that compensates for phase noise in a wireless communication system,
A transmission / reception unit; And
And generates information on association between at least one phase tracking reference signal (PTRS) port and at least one demodulation reference signal (DMRS) port, And a controller for controlling the terminal to transmit information on the association to compensate for phase noise between the base station and the base station. The information processing method according to claim 16,
Wherein the PTRS port indicates quasi-co-location with the DMRS port. 17. The base station of claim 16, wherein the information about the association is transmitted through higher layer signaling. 17. The base station of claim 16, wherein a PTRS port in a multi-transmission and reception point environment is used to estimate phase noise occurring in an oscillator corresponding to the PTRS port. The information processing method according to claim 16,
Wherein the base station comprises at least one of a delay spread, a Doppler spread, a Doppler shift, an average delay, and an average gain.

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