KR20180090718A - Control method of wireless communication in cellular system based on beamfoaming - Google Patents

Abstract

The present disclosure relates to a communication technique for fusing a 5G communication system supporting a higher data transfer rate than a 4G system with an IoT technology, and a system thereof. The present disclosure can be applied to intelligence type services (for example, a smart home, a smart building, a smart city, a smart car, or a connected car, healthcare, digital education, retail business, security and safety related services, etc.) based on a 5G communication technology and an IoT related technology. The present invention provides a method for transmitting a reference signal (RS) for supporting mobility based on an uplink. A method for processing a control signal in a wireless communication system comprises the following steps of: receiving a first control signal transmitted from a base station; processing the received first control signal; and transmitting a second control signal generated based on the process to the base station.

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.

According to an aspect of the present invention, there is provided a method of processing a control signal in a wireless communication system, the method comprising: receiving a first control signal transmitted from a base station; Processing the received first control signal; And transmitting the second control signal generated based on the process to the base station.

According to an embodiment of the present invention, an RS capable of supporting UL-based mobility can be expected to reduce the power of the UE and increase the efficiency of paging resource between cells.

Also, according to an embodiment of the present invention, efficient system operation can be performed through mapping between PTRS and another RS.

FIG. 1A is a diagram illustrating a conceptual diagram of uplink-based RRM measurement.
1B shows a PRACH configuration transmitted to the SIB.
1C is a diagram showing a prach configIndex indicating a subframe index for PRACH transmission in the FDD.
1D is a diagram showing a prach configIndex indicating a subframe index for PRACH transmission in TDD.
FIG. 1E is a diagram illustrating a UE-dedicated RRC message for receiving a RACH in a common region. FIG.
1F is a diagram showing a RACH preamble format in LTE.
FIG. 1G is a diagram illustrating an embodiment of a RACH configuration for performing UL beam measurement.
1 h is a diagram showing an embodiment of the PRACH format.
1I is a diagram showing an SRS configuration for periodic SRS transmission.
1J is a diagram illustrating a first method of setting a sub-time unit due to a fourth method supporting RS for RRM measurement.
FIG. 1K is a diagram illustrating a cell-specific SRS configuration for uplink RRM measurement.
FIG. 11 is a diagram illustrating a UE-specific SRS configuration for supporting uplink-based mobility.
1M is a diagram illustrating a method for indicating a mechanism for UL beam measurement.
FIG. 1n shows an embodiment of a cell-specific SRS configuration for UL beam measurement.
Figure 1 o illustrates one embodiment of a UE-specific SRS configuration for UL beam measurement.
FIG. 1P is a diagram illustrating an embodiment of how a UE specific SRS is generated within a UE specific BW.
FIG. 1Q is a diagram illustrating a method of transmitting SRS between UEs by partially overlapping using a minimum unit SRS sequence generation method.
FIG. 2A is a diagram showing the effect of phase noise. FIG.
FIG. 2B is a diagram illustrating a relationship between a PTRS port and a DMRS port in various TRP multi-panel environments.
FIG. 2C is a diagram illustrating a process of defining a relation between a PTRS port and a DRMS port by a pre-defined method.
FIG. 2D is a diagram illustrating a relationship between a PTRS port and a DMRS port through an indication signaling in a multi-TRP environment.
2E is a diagram illustrating an example of a process of resetting a PTRS port in a multi-TRP environment.
FIG. 2F is a diagram illustrating a procedure for defining a PTRS port setting and a DMRS port relationship in a multi-panel and multiple oscillator environment of a terminal.
FIG. 2G is a diagram illustrating a relationship between a CSI-RS port and a PTRS port.

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. Herein, the base station transmits an RS for RRM measurement to the UE, the UE measures the RRM of each cell using the RS, and reports the 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. 1A shows a conceptual diagram for measuring an uplink-based RRM. Assuming that there are N base stations, each of the N base stations must be able to receive the RS transmitted from the terminal at the same time. After receiving the RS from the terminal, the base station responds to the terminal with a result of the RRM measurement after a predetermined processing time. An important part here is that, in the uplink, it is necessary to define a common area (UL common region) in which all base stations such as the downlink can receive the RS.

FIG. 1A shows a conceptual diagram for measuring an uplink-based RRM. Assuming that there are N base stations, each of the N base stations must be able to receive the RS transmitted from the terminal at the same time. After receiving the RS from the terminal, the base station responds to the terminal with a result of the RRM measurement after a predetermined processing time. An important part here is that, in the uplink, it is necessary to define a common area (UL common region) in which all base stations such as the downlink can receive the RS.

FIG. 1B shows a RACH configuration transmitted to the SIB.

The PRACH configuration shown in FIG. 1B is a cell specific signal. That is, all terminals in the cell commonly receive and signify signals. Among the signals shown in FIG. 1B, prach_ConfigIndex is a parameter indicating a subframe in which a PRACH can be transmitted in a cell, and FDD is shown in FIG. 1c.

TDD is shown in Fig. 1d.

Referring to FIGS. 1C and 1D, the RACH in the cell can be informed via the SIB to the subframe index that the BS can receive / transmit from the UE. 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. 1C and FIG. 1D to the same value between adjacent cells. That is, all terminals can receive the PRACH transmitted by the UE by sharing the RACH transmit / receive subframe index between the cells. 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 measuring the uplink RRM of the UE includes transmitting the PRACH configuration shown in FIG. 1B to the UE using the RRC, and sharing the messages 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. In order to receive the RACH in the inter-cell common region shown in FIG. 1A, it is defined as RACH configCommonRegion.

A third method for the RS supporting the RS for measurement of the uplink RRM of the UE is to transmit the PRACH configuration shown in FIG. 1B 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 to be transmitted to the DCI, which may appear as OH in 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 . 1F shows a RACH preamble format defined in LTE. 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 CP length that is twice the cell coverage as shown in FIG. 1F. 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 shown in FIG. 1E 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 allocated so that there is no inter-cell collision. However, as shown in FIG. 1A, 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. 1F 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.

The prach_configBeam shown in FIG. 1G 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. As shown in FIG. 1 (h), different prach formats can be used for transmission according to the value of prach_preamble_format. Max_prach_format is a parameter that tells you how many prach symbols are repeated in a given format when using a preamble format.

1I is a diagram showing a configuration for transmitting periodic SRS defined in LTE.

The Sounding RS-UL-Config command shown in FIG. 1I 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 the subcarrier spacing for the SRS resource configuration.

A fourth method of supporting the RS for measuring the uplink RRM of the UE is a method in which all BSs share the cell specific SRS configuration shown in FIG. 1k. 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 defined as a cell-specific SRS configuration for the uplink RRM measurement as shown in FIG. 11, 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. 1J is a diagram illustrating a first method for setting a sub-time unit due to a fourth method for supporting RS for RRM measurement. The base station may also calculate the sub-time as shown in FIG. 1J and perform beam sweeping in each sub-time unit. Unlike the method shown in FIG. 1J, 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.

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 uplink RRM measurement as shown in FIG. 1k, and add this configuration to all 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.

FIG. 11 includes UE-specific configuration for periodic SRS transmission and aperiodic SRS transmission. It should be noted that the sharing between the neighboring cells of the configuration for RACH and SRS transmission described above is the same as setting the common region shown in FIG. 1A. Accordingly, neighbor BSs can receive the SRS / RACH transmitted by the UE and respond to the received SRS / RACH.

Also, SRS can be used for UL beam measurement like 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. 1m 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. The other mode can inform the SRS that it is used for CSI acquisition.

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

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 multiple SRSs, a cell-specific SRS configuration as shown in FIG. 1k 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.

A cell-specific SRS configuration, such as 1o, must be provided to transmit multiple SRSs within a symbol, a third method for transmitting multiple 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 1p is a diagram illustrating how a UE-specific SRS is generated within a UE-specific BW. In the figure, 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. When a sequence length of a minimum unit is allocated as shown in FIG. 1P, the orthogonality of the sequence can be satisfied in the RB of the minimum unit. Therefore, 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. Figure 2a shows this signal attenuation effect. 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. FIG. 2B is a diagram illustrating a relationship between a PTRS port and a DMRS port in various TRP multi-panel environments. Case 1 is an environment where two panels use one oscillator. In case 2, two panels use two oscillators. In case 1, since the phase noise source is one, the phase noise can be compensated by using one PTRS port. In case 2, however, two independent PTRS ports are needed to measure and compensate for independent phase noise for each panel. At this time 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 and DMRS port 3 of case 2 should use PTRS port. 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 that it operates without restriction to specific DL and 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. FIG. 2C shows a series of processes described above. 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. 2D is a diagram illustrating a relationship between a PTRS port and a DMRS port in a multi-TRP environment. 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. Specifically, as shown in FIG. 2E, 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 DMRS port and the PTRS port must be specified.

FIG. 2F shows a process of 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.

FIG. 2G 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.

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 (1)

A method for processing a control signal in a wireless communication system,
Receiving a first control signal transmitted from a base station;
Processing the received first control signal; And
And transmitting the second control signal generated based on the process to the base station.

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