WO2020050653A1 - Method and device for generating reference signal sequence for papr reduction in mobile communication system - Google Patents

Abstract

The present disclosure relates to a method for transmitting or receiving a signal by a terminal in a wireless communication system. A terminal according to an embodiment may: transmit terminal capability information relating to sequence initialization of a demodulation reference signal (DMRS) to a base station; receive DMRS configuration information determined on the basis of the terminal capability information from the base station; and receive the DMRS from the base station on the basis of the DMRS configuration information, wherein the DMRS is generated on the basis of a sequence initialization parameter determined on the basis of a code division multiplexing (CDM) group identifier included in the DMRS configuration information.

Description

Method and apparatus for generating a reference signal sequence for PAPR reduction in a mobile communication system

The present disclosure relates to a method and apparatus for generating a reference signal sequence for PAPR reduction in this mobile communication system.

Efforts have been made to develop an improved 5G communication system or a pre-5G communication system to meet the increasing 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) or a system after an LTE system (Post LTE). The 5G communication system established by 3GPP is called a New Radio (NR) system. To achieve high data rates, 5G communication systems are being considered for implementation in the ultra-high frequency (mmWave) band (eg, 60 gigahertz (60 GHz) band). In order to mitigate the path loss of radio waves in the ultra-high frequency band and increase the transmission distance of radio waves, in 5G communication systems, beamforming, massive array multiple input / output (massive MIMO), full dimensional multiple input / output (FD-MIMO) ), Array antenna, analog beam-forming, and large scale antenna techniques have been discussed and applied to NR systems. In addition, in order to improve the network of the system, in the 5G communication system, an evolved small cell, an advanced small cell, a cloud radio access network (cloud RAN), an ultra-dense network , Device to Device communication (D2D), wireless backhaul, mobile network, cooperative communication, coordinated multi-points (CoMP), and interference cancellation Technology development is being conducted. In addition, in the 5G system, advanced coding modulation (Advanced Coding Modulation (ACM)), hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC), advanced access technologies, FBMC (Filter Bank Multi Carrier), and NOMA (non-orthogonal multiple access), and SCMA (sparse code multiple access) are being developed.

Meanwhile, the Internet is evolving from a human-centered connection network in which humans generate and consume information, to an Internet of Things (hereinafter referred to as IoT) network that exchanges information between distributed components such as objects. The Internet of Everything (IoE) technology, which combines big data processing technology through connection with cloud servers and the like, is emerging. In order to implement the IoT, technical elements such as sensing technology, wired / wireless communication and network infrastructure, service interface technology, and security technology are required, and recently, a sensor network for connection between things, a machine to machine , M2M), Machine Type Communication (MTC), etc. are being studied. In an IoT environment, an intelligent IT (Internet Technology) service that collects and analyzes data generated from connected objects to create new values in human life may be provided. IoT is a field of smart home, smart building, smart city, smart car or connected car, smart grid, health care, smart home appliance, high-tech medical service through convergence and combination between existing information technology (IT) technology and various industries. It can be applied to.

Accordingly, various attempts have been made to apply a 5G communication system to an IoT network. For example, 5G communication 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 antenna. It may be said that the application of cloud radio access network (cloud RAN) as the big data processing technology described above is an example of 5G technology and IoT technology convergence.

As it is possible to provide various services according to the above-mentioned and development of a mobile communication system, a method for effectively providing these services is required.

The disclosed embodiment provides an apparatus and method capable of effectively providing a service in a mobile communication system.

The present disclosure relates to a method for a terminal to transmit / receive a signal in a wireless communication system, and the terminal according to an embodiment transmits capability information of the terminal regarding sequence initialization of a demodulation reference signal (DMRS) to the base station, and the terminal from the base station DMRS configuration information is determined based on the capability information of the DMRS, DMRS is received from a base station based on the DMRS configuration information, and DMRS is based on a code division multiplexing (CDM) group identifier included in the DMRS configuration information. It can be generated based on the determined sequence initialization parameter.

According to the disclosed embodiment, it is possible to effectively provide a service in a mobile communication system.

1 is a view showing a structure of a time-frequency domain, which is a radio resource domain in which data or control channels are transmitted in a downlink of an LTE / LTE-A system.

FIG. 2 is a diagram illustrating a structure of a time-frequency domain, which is a radio resource domain in which data or a control channel is transmitted in an uplink of an LTE / LTE-A system.

FIG. 3 is a diagram illustrating radio resources of 1 Resource Block (RB), which is a minimum unit that can be scheduled in a downlink of an LTE / LTE-A system.

4 is a diagram illustrating a scrambling code generation process.

5 is a block diagram showing the structure of a base station according to an embodiment.

6 is a block diagram showing the structure of a terminal according to an embodiment.

In a wireless communication system according to an embodiment, a method for a terminal to transmit / receive a signal includes: transmitting capability information of a terminal regarding sequence initialization of a demodulation reference signal (DMRS) to a base station; Receiving DMRS configuration information determined based on the capability information of the terminal from the base station; And receiving the DMRS from the base station based on the DMRS configuration information, and the DMRS may be generated based on a sequence initialization parameter determined based on a code division multiplexing (CDM) group identifier included in the DMRS configuration information. .

In a method for a terminal to transmit and receive a signal in a wireless communication system according to an embodiment, the sequence initialization parameter is a parameter corresponding to the CDM group identifier and the CDM group identifier

Is determined on the basis of,

The initialization parameter of each of the different CDM group identifiers determined in the same manner may have different values based on the CDM group identifier.

In a method for a terminal to transmit and receive a signal in a wireless communication system according to an embodiment, the parameter corresponding to the CDM group identifier

, May be determined for each CDM group identifier using the parameter value obtained through DCI.

In a method for a terminal to transmit / receive a signal in a wireless communication system according to an embodiment, a sequence initialization parameter determined based on a DCM group identifier may be applied to both DMRS type 1 and DMRS type 2.

In a method for a terminal to transmit / receive a signal in a wireless communication system according to an embodiment, DMRS is a PUSCH or a PDSCH scheduled by a DCI format other than DCI format 0_0 or DCI format 1_0, the code division multiplexing (CDM) It can be generated based on the sequence initialization parameter determined based on the group identifier.

In a wireless communication system according to an embodiment, a method for a base station to transmit / receive a signal includes: receiving capability information of a terminal regarding sequence initialization of a demodulation reference signal (DMRS) from the terminal; Transmitting DMRS configuration information determined based on the capability information of the terminal to the terminal; And transmitting the DMRS to the terminal, the DMRS may be generated based on a sequence initialization parameter determined based on a code division multiplexing (CDM) group identifier included in the DMRS configuration information.

In a method for a base station to transmit and receive signals in a wireless communication system according to an embodiment, the sequence initialization parameter is a parameter corresponding to the CDM group identifier and the CDM group identifier.

Is determined on the basis of,

The initialization parameter of each of the different CDM group identifiers determined in the same manner may have different values based on the CDM group identifier.

In a method for a base station to transmit and receive signals in a wireless communication system according to an embodiment, the sequence initialization parameter determined based on the DCM group identifier may be applied to both DMRS type 1 and DMRS type 2.

A terminal for transmitting and receiving signals in a wireless communication system according to an embodiment includes: a transmitting and receiving unit; And a processor, the processor transmits the capability information of the terminal regarding the sequence initialization of the DMRS (demodulation reference signal) to the base station, and receives the DMRS configuration information determined based on the capability information of the terminal from the base station And, to receive and receive the DMRS from the base station based on the DMRS configuration information, and controls the transceiver, DMRS is generated based on the sequence initialization parameters determined based on the code division multiplexing (CDM) group identifier included in the DMRS configuration information You can.

In a wireless communication system according to an embodiment, a base station for transmitting and receiving signals includes: a transmitting and receiving unit; And a processor, the processor receives the capability information of the terminal regarding the sequence initialization of the demodulation reference signal (DMRS) from the terminal, and transmits the DMRS configuration information determined based on the capability information of the terminal to the terminal And, to control the transmitting and receiving unit to transmit the DMRS to the terminal, DMRS may be generated based on the sequence initialization parameter determined based on the code division multiplexing (CDM) group identifier included in the DMRS configuration information.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In describing the embodiments, descriptions of technical contents that are well known in the art to which the present disclosure belongs and are not directly related to the present disclosure will be omitted. This is to more clearly and without obscuring the subject matter of the present disclosure by omitting unnecessary description.

For the same reason, some components in the accompanying drawings are exaggerated, omitted, or schematically illustrated. Also, the size of each component does not entirely reflect the actual size. The same or corresponding elements in each drawing are given the same reference numerals.

Advantages and features of the present disclosure, and a method of achieving them will be apparent with reference to embodiments described below in detail together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only the present embodiments allow the present disclosure to be complete, and those skilled in the art to which the present disclosure pertains. It is provided to fully inform the person of the scope of the invention, and the present disclosure is only defined by the scope of the claims. The same reference numerals refer to the same components throughout the specification.

At this time, it will be understood that each block of the process flow chart drawings and combinations of the flow chart drawings can be performed by computer program instructions. These computer program instructions may be mounted on a processor of a general purpose computer, special purpose computer, or other programmable data processing equipment, so that instructions performed through a processor of a computer or other programmable data processing equipment are described in flowchart block (s). It creates a means to perform functions. These computer program instructions can also be stored in computer readable or computer readable memory that can be oriented to a computer or other programmable data processing equipment to implement a function in a particular manner, so that computer readable or computer readable memory It is also possible for the instructions stored in to produce an article of manufacture containing instructions means for performing the functions described in the flowchart block (s). Since computer program instructions may be mounted on a computer or other programmable data processing equipment, a series of operational steps are performed on the computer or other programmable data processing equipment to create a process that is executed by the computer to generate a computer or other programmable data. It is also possible for instructions to perform processing equipment to provide steps for executing the functions described in the flowchart block (s).

Also, 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, it is also possible that the functions mentioned in the blocks occur out of sequence. For example, two blocks shown in succession may in fact be executed substantially simultaneously, or it is also possible that the blocks are sometimes executed in reverse order according to a corresponding function.

At this time, the term '~ unit' used in this embodiment means a hardware component such as software or an FPGA or an ASIC, and '~ unit' performs certain roles. However, '~ wealth' is not limited to software or hardware. The '~ unit' may be configured to be in an addressable storage medium or may be configured to reproduce one or more processors. Thus, as an example, '~' means components such as software components, object-oriented software components, class components, and task components, and processes, functions, properties, procedures, and the like. Subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within components and '~ units' may be combined into a smaller number of components and '~ units', or further separated into additional components and '~ units'. In addition, the components and '~ unit' may be implemented to play one or more CPUs in the device or secure multimedia card. Also, in the embodiment, '~ unit' may include one or more processors.

Terms used to identify connection nodes, terms referring to network entities, terms referring to messages, terms referring to interfaces between network objects, and terms referring to various identification information used in the following description. Etc. are illustrated for convenience of description. Therefore, it is not limited to the terms used in the present disclosure, and other terms indicating objects having equivalent technical meanings may be used.

For convenience of description below, the present disclosure uses terms and names defined in a standard for 5G or NR, LTE system. However, the present disclosure is not limited by these terms and names, and may be equally applied to systems conforming to other standards.

In other words, in specifically describing the embodiments of the present disclosure, 3GPP will mainly target a communication standard for which a standard is set, but the main subject matter of the present disclosure is to greatly expand the scope of the present invention to other communication systems having similar technical backgrounds. It can be applied with a slight modification within a range that does not deviate, which will be possible by the judgment of a person skilled in the technical field of the present disclosure.

In FIG. 1, the horizontal axis represents the time domain and the vertical axis represents the frequency domain. The minimum transmission unit in the time domain is an OFDM symbol, and Nsymb (102) OFDM symbols are aggregated to form one slot 106, and two slots are aggregated to form one subframe (105). The length of the slot is 0.5 ms, and the length of the subframe is 1.0 ms. The radio frame 114 is a time domain section composed of 10 subframes. The minimum transmission unit in the frequency domain is a subcarrier, and the bandwidth of the entire system transmission bandwidth is composed of a total of NBW 104 subcarriers.

The basic unit of resources in the time-frequency domain is a resource element (112, Resource Element, RE), which may be represented by an OFDM symbol index and a subcarrier index. The resource block 108 (Resource Block, RB or Physical Resource Block, PRB) is defined by Nsymb (102) consecutive OFDM symbols in the time domain and NRB (110) consecutive subcarriers in the frequency domain. Therefore, one RB 108 is composed of Nsymb x NRB REs 112. Generally, the minimum transmission unit of data is an RB unit. In LTE systems, Nsymb = 7, NRB = 12, and NBW and NRB are generally proportional to the bandwidth of the system transmission band. The data transmission rate increases in proportion to the number of RBs scheduled for the terminal. The LTE system operates by defining six transmission bandwidths. In the case of an FDD system in which the downlink and the uplink are divided into frequencies, the downlink transmission bandwidth and the uplink transmission bandwidth may be different. The channel bandwidth represents the RF bandwidth corresponding to the system transmission bandwidth. [Table 1] shows the correspondence between the system transmission bandwidth and channel bandwidth defined in the LTE system. For example, in an LTE system having a 10 MHz channel bandwidth, the transmission bandwidth is composed of 50 RBs.

[Table 1]

FIG. 2 is a diagram illustrating a structure of a time-frequency domain, which is a radio resource domain in which data or a control channel is transmitted in an uplink of LTE / LTE-A system.

2, the horizontal axis represents the time domain, and the vertical axis represents the frequency domain. The minimum transmission unit in the time domain is the SC-FDMA symbol 202,                 

One SC-FDMA symbol is collected to form one slot 206. In addition, two slots are collected to form one subframe 205. The minimum transmission unit in the frequency domain is a subcarrier, and the total system transmission bandwidth (204) is the total NBW.                  It consists of two subcarriers. NBW has a value in proportion to the system transmission band.

The basic unit of resources in the time-frequency domain is a resource element (RE, 212), which can be defined as an SC-FDMA symbol index and a subcarrier index. Resource block pair (208, Resource Block pair, RB pair) in the time domain

SC-FDMA symbols and frequency domains

It is defined as two consecutive subcarriers 210. Therefore, one RB

x

It consists of REs. Generally, the minimum transmission unit of data or control information is an RB unit. In the case of PUCCH, it is mapped to a frequency domain corresponding to 1 RB and transmitted during 1 subframe.

Even in the case of 5G or new radio (NR) system, a downlink / uplink structure similar to that of Figs. 1 and 2 is supported. The 5G or NR system has a more flexible structure in the time axis than the LTE system, specifically a slot structure composed of 14 OFDM symbols and 1, 2, 3, 4, or 7 OFDM symbols. Support non-slot structures. The non-slot structure can also be referred to as a mini-slot structure.

FIG. 3 is a diagram illustrating radio resources of 1 Resource Block (RB), which is a minimum unit that can be scheduled in a downlink of an LTE / LTE-A system.

3, a plurality of different types of signals may be transmitted to the radio resource shown in FIG.

1. CRS (Cell Specific RS): This is a reference signal that is periodically transmitted for all terminals belonging to one cell and can be commonly used by a plurality of terminals.

2. DMRS (Demodulation Reference Signal): a reference signal transmitted for a specific terminal and transmitted only when data is transmitted to the corresponding terminal. The DMRS can consist of a total of 8 DMRS ports. In the LTE / LTE-A system, ports 7 to 14 correspond to DMRS ports, and the ports maintain orthogonality so that they do not interfere with each other by using Code Division Multiplexing (CDM) or Frequency Division Multiplexing (FDM). .

3.PDSCH (Physical Downlink Shared Channel): a data channel transmitted in a downlink, used by a base station to transmit traffic to a terminal, and transmitted using RE in which a reference signal is not transmitted in the data region of FIG. 3

4. CSI-RS (Channel Status Information Reference Signal): a reference signal transmitted for UEs belonging to one cell, used to measure channel status. Multiple CSI-RSs can be transmitted to one cell.

5. Other control channels (PHICH, PCFICH, PDCCH): Provides control information necessary for the UE to receive PDSCH or transmits ACK / NACK to operate HARQ for uplink data transmission

4 is a diagram illustrating a scrambling code generation process.

Referring to FIG. 4, in the case of the LTE system, the CRS, DMRS, and CSI-RS reference signal sequences, and the sequences for scrambling of various channels such as PDCCH, PDSCH, and PMCH are Gold sequences of length 31. It is generated as a PN (Pseudo-random) sequence. More specifically, as in FIG. 4, the polynomial of the upper register

Polynomial of the first m-sequence x1 (n) and the lower register generated from

PN sequence c (n) is generated by concatenating the second m-sequence x2 (n), which can be expressed by Equation 1 below.

[Equation 1]

Here, Nc = 1600, and the initialization of the register is performed as follows.

-The first m-sequence x1 (n) generated from the upper register is initialized as the following fixed pattern x1 (0) = 1, x1 (n) = 0, n = 1,2, ..., 30 .

 -The first m-sequence x2 (n) generated from the upper register is initialized by the following equation according to the scrambling condition required by each signal.

[Equation 2]

In [Equation 2], Cinit may be determined by applying different methods according to a detailed application.

For example, a bit block on each codeword q

Can be scrambled according to [Equation 3]. here,

Is a number of bits included in codeword q transmitted in one slot in a corresponding channel (PDSCH, PDCCH, or PMCH).

[Equation 3]

Scrambling sequence in Equation 3

Is determined by [Equation 1], and the corresponding scrambling sequence is initialized by Cinit at the beginning of each subframe. At this time, the cinit is defined as [Equation 4] according to the type of the transport channel.

[Equation 4]

here,

Is an RNTI (Radio Network Temporary Identifier) allocated when transmitting PDSCH,

Is the slot number in the transmission frame,

Is Cell ID, and

Indicates MBSFN area identity. Up to two codewords can be transmitted in one subframe.

{0, 1}. If a single codeword is transmitted, q becomes 0.

Block of scrambled bits through [Equation 3]

Is then mapped and transmitted to RE through appropriate procedures, such as modulation, codeword-to-layer mapping, and precoding.

As another example, in the case of CRS, within one radio frame

The reference signal having the slot number of and the OFDM symbol number of l in the corresponding slot has a sequence as shown in [Equation 5].

[Equation 5]

At this time, c (i) is determined by Equation 1 and is initialized by Cinit at the beginning of every OFDM symbol. At this time, Cinit is determined by [Equation 6].

[Equation 6]

In Equation 6, Ncp has a value of 1 for normal CP and 2 for extended CP.

The CRS sequence generated through Equation 5 is slot through Equation 7.

It is mapped to the reference signal for the antenna port p of.

[Equation 7]

Here, subcarrier number k, OFDM symbol number l, and sequence number m 'have the following relationship.

[Equation 8]

In addition, in the equation (8), the variable v and

Defines the reference signal position on the frequency axis as shown in [Equation 9] according to l and p.

[Equation 9]

As another example, in the case of LTE DMRS, [Equation 2] is represented by [Equation 10] below to transmit the DMRS port p = 5.

[Equation 10]

In [Equation 10]

Indicates a slot number in a transmission frame,

Indicates the UE ID. And

Indicates Cell ID. In contrast, the DMRS port

To transmit {7,8, ... 14}, [Equation 2] is represented as [Equation 11] below.

[Equation 11]

In [Equation 11]

Indicates a slot number in a transmission frame,

Indicates a Scrambling ID having a value of 0 or 1, and the value of the Scrambling ID is assumed to be 0 when there is no specific mention. Also,

Is determined as follows.

-

, if no value for

is provided by higher layers or if DCI format 1A, 2B or 2C is used for the DCI associated with the PDSCH transmission

-

, otherwise

As described above, in the case of DMRS, initialization is performed every subframe and the DMRS port

The reference signal for transmitting {7,8, ... 14} is expressed as [Equation 12] below.

[Equation 12]

here,

As a maximum number of RBs supported for DL in the LTE system. In addition, since the LTE system uses a fixed DMRS pattern for the normal CP and the extended CP, the DMRS sequence is generated as shown in [Equation 11] in consideration of the number of DMRS REs per PRB.

As another example, LTE CSI-RS in one radio frame

The reference signal having the slot number of and the OFDM symbol number of l in the corresponding slot has a sequence as shown in [Equation 13].

[Equation 13]

At this time, c (i) is determined by Equation 1 and is initialized by Cinit at the beginning of every OFDM symbol. At this time, Cinit is determined by Equation (14).

[Equation 14]

In Equation 14, Ncp has a value of 1 for normal CP and 2 for extended CP.

In the case of, it can be set separately through higher layer signaling, and if it is not configured as higher layer signaling

It has the same value as

Reference signal sequence as shown in [Equation 15] below for the antenna port p based on [Equation 13]

Maps.

[Equation 15]

Here, orthogonal cover code (OCC)

, subcarrier number k, OFDM symbol number l, and sequence number m 'have the following relationship.

[Equation 16]

On the other hand, unlike the LTE system, in the 5G or NR system, increased cell-ID, increased channel bandwidth, various subcarrier spacing support, slot-based transmission and slot aggregation support, and various reference signal RE mapping structures are considered. Accordingly, the method of generating the reference signal and the scrambling sequence may also be changed in consideration of this.

For example, since the 5G or NR system supports numerologies such as [Table 2], the number of slots in one frame composed of 10 subframes having 1 ms duration is shown in [Table 3]. Same as [Table 3]

Is one frame, that is, the number of slots included in 10 ms.

Is a number of subframes, that is, slots included in 1 ms.

[Table 2]

Table 2 shows the supported transmission numerologies.

[Table 3]

[Table 3] shows the Number of OFDM symbols per slot for the normal cyclic prefix.

And slot number based on one frame as in the LTE system.

If you define

It means that the maximum value of may vary depending on the numerology. In the description below, slot numbers that vary according to numerology are

It is named as.

In 5G or NR system, CSI-RS supports the following sequence initialization method considering the variable numerology of 5G or NR system. First, in a 5G or NR system, CSI-RS uses the same method as the sequence generation described in [Equation 1] to [Equation 5], and at this time, sequence initialization as shown in [Equation 17] is used.

[Equation 17]

[Equation 17]

And

Is followed by the above description, l is the OFDM symbol index in the slot, and n _ID is the scrambling ID set through the upper layer. According to the above description, the sequences generated through [Equation 1], [Equation 5], and [Equation 17] follow the rules of [Equation 18] below.

Is mapped to RE.

[Equation 18]

In [Equation 18], p is the CSI-RS port index,

Is a transmission power of CSI-RS, and Wf (k ') and Wt (l') are orthogonal cover code values according to k 'and l' values of Tables 4 and 5,

Means a sequence value. At this time, the sequence index m 'is PRB index n, CSI-RS density

Decided by

, And the starting position of the frequency axis of the CSI-RS CDM group determined according to [Table 4]

And time axis starting position

It is defined as a function of

[Table 4]

[Table 5]

Referring to [Equation 18] and [Table 4], all CSI-RS ports in one CSI-RS resource use the same sequence, and one or more CDM groups constituting one CSI-RS resource have the same OFDM. It can be seen that it can be transmitted in symbol. Specifically, this means that in the case of a CSI-RS resource including more than 4 ports, a sequence of the same value in the OFDM symbol can be repeated and mapped to subcarriers, and the OFDM symbol including the CSI-RS Deterioration of peak-to-average-power-ratio (PAPR) characteristics can increase the dynamic range of base station power amplifiers (PAs) and increase implementation and maintenance costs. Similar problems can occur in other RSs, such as DMRS.

In order to solve this problem, the present disclosure describes a method of improving the PAPR characteristics of OFDM symbols including RS by improving the sequence initialization method of CSI-RS and DMRS.

More specifically, the present disclosure describes a method and apparatus for generating a reference signal sequence for reducing peak-to-average power ratio (PAPR) of a mobile communication system. In the case of CSI-RS in a 5G or NR system, the same RS sequence is applied to all CSI-RS ports in one CSI-RS resource. Accordingly, when a plurality of CSI-RS ports are transmitted in one OFDM symbol, the same sequence values are repeated to increase the PAPR of the transmitted signal, which in turn leads to an increase in base station implementation and maintenance cost. In addition, the present disclosure is a reference signal in a 5G or NR system through various methods such as extension of the reference signal sequence length, time / frequency resource index modulo operation, combination adjustment of various input values, and initialization of a sequence according to a CDM or antenna port number. Describes how to create a sequence and initialize it.

Hereinafter, an embodiment of the present disclosure will be described using an LTE or LTE-A system as an example, but the embodiment of the present disclosure may be applied to other communication systems having similar technical backgrounds or channel types. For example, 5G mobile communication technology (5G, new radio, NR) developed after LTE-A may be included in this. More specifically, in a 5G or NR system, a basic structure of a time-frequency domain in which signals are transmitted in downlink and uplink may be different from FIGS. 1 and 2. In addition, the types of signals transmitted through downlink and uplink may also be different. For example, in the case of 5G or NR systems, additional reference signals may be supported compared to LTE systems such as PT-RS (phase tracking RS), TRS (time / frequency tracking RS), and CSI-RS and DMRS are also set in various forms. It is possible. Accordingly, the embodiments of the present disclosure may be applied to other communication systems through some modifications within a range not significantly departing from the scope of the present disclosure as determined by a person having skilled technical knowledge.

In addition, in describing the present disclosure, when it is determined that a detailed description of related functions or configurations may unnecessarily obscure the subject matter of the present disclosure, the detailed description will be omitted. In addition, terms to be described later are terms defined in consideration of functions in the present disclosure, which may vary according to a user's or operator's intention or practice. Therefore, the definition should be made based on the contents throughout this specification. Hereinafter, the base station is a subject that performs resource allocation of a terminal, and may be at least one of an eNode B, a Node B, a base station (BS), a radio access unit, a base station controller, or a node on a network. The terminal may include a user equipment (UE), a mobile station (MS), a cellular phone, a smart phone, a computer, or a multimedia system capable of performing a communication function. In the present disclosure, a downlink (DL) is a radio transmission path of a signal transmitted by a base station to a terminal, and an uplink (UL) means a radio transmission path of a signal transmitted by a terminal to a base station.

The data scrambling described below includes all scrambling applied to a bit sequence including information other than a predetermined signal such as a reference signal and a sync signal, and can be expressed in various terms such as PDSCH scrambling, PUSCH scrambling, and PMCH scrambling.

The CSI-RS described below refers to a reference signal transmitted by a base station to enable a UE to measure downlink channel state information, and the UE performs various operations such as CSI reporting, beam management, and UE mobility related reporting. can do.

The SRS described below refers to a reference signal transmitted by the terminal to enable the base station to measure uplink channel state information, and the base station determines an uplink beamforming or precoding direction through this, and instructs the terminal to this. Various operations can be performed.

The DMRS (Demodulation reference signal) described below refers to a reference signal having a feature capable of performing demodulation without receiving additional precoding information by transmitting UE-specific precoding on a reference signal and transmitting an LTE system. Use the name used in. However, the term for DMRS may be expressed in other terms according to a user's intention and purpose of using a reference signal. For example, it may be expressed in terms such as UE-specific RS or dedicated RS.

Terms such as data scrambling / CSI-RS / DMRS / SRS are merely illustrative of the technical contents of the present disclosure and provided with specific examples to help understanding of the present disclosure, that is, other terms based on the technical spirit of the present disclosure. It is obvious to those of ordinary skill in the art to which the above operation can be performed.

In the first embodiment of the present disclosure described below, a CSI-RS sequence initialization method in a 5G or NR system and signaling methods therefor are described. In Embodiment 2 of the present disclosure, a method for initializing a DMRS sequence in a 5G or NR system and signaling methods for the same are described. In Embodiment 3 of the present disclosure, a method for initializing CSI-RS and DMRS sequences according to network synchronization (whether it is a synchronous network or an asynchronous network) and signaling methods for the same are described.

<First Example>

In the first embodiment, an initialization method for generating a CSI-RS sequence is described. In the case of the Rel-15 NR system, the base station and the terminal use a sequence generator based on [Equation 1] and [Equation 5] and generate a sequence. At this time, use [Equation 19] below in every OFDM symbol. To initialize the sequence.

[Equation 19]

As described above, in the case of [Equation 19], there is a risk of deteriorating the PAPR characteristics of the CSI-RS OFDM symbol by assigning the same sequence value to multiple CDM groups. One of the methods to solve this is to use different sequence initialization for each CDM group in CSI-RS.

For example, it is possible for the base station and the terminal to additionally use the CDM group index j of [Table 4] for sequence initialization.

[Equation 20] is a method of determining the sequence initialization value by adding the CDM group index j to the OFDM symbol position l. This allows CDM groups in one OFDM symbol to use an RS sequence similar to CDM groups of adjacent OFDM symbols, and reuses existing (eg, in Rel-15) RS sequence cell planning of the base station. It makes it easy.

[Equation 20]

[Equation 21] is a method of determining the sequence initialization value by multiplying the OFDM symbol position l by the CDM group index j. This has the effect of differently allocating intervals of sequence initialization values used by CDM groups in one OFDM symbol over time, and can increase the randomness of reference signal interference.

[Equation 21]

[Equation 22] is the slot number

This is a method of determining the sequence initialization value by multiplying CDM group index j by. This has the effect of preventing CDM groups from using the same sequence initialization value in one slot, which is easy to manage reference signal interference.

[Equation 22]

[Equation 23] is the scrambling ID term

This is a method of determining the sequence initialization value by summing up the CDM group index j. This has the effect of preventing the CDM groups from using the same sequence initialization value regardless of the time position of the CSI-RS OFDM symbol, so it is easy to manage reference signal interference.

[Equation 23]

[Equation 24] is a method of determining the sequence initialization value by adding the CDM group index j to the Rel-15 sequence initialization value. This allows CDM groups in one OFDM symbol to use consecutive sequence initialization, and facilitates reuse of the base station's existing RS sequence cell planning (eg, in Rel-15).

[Equation 24]

[Equations 20] to [Equation 24] are examples for helping understanding of the first embodiment, and it is possible to apply other methods similar to the present invention without being limited thereto.

Meanwhile, one of [Equation 20] to [Equation 24] is not used alone, but can be used with [Equation 19] for backward compatibility. For example, the UE is capable of supporting only the initialization of the sequence by [Equation 19], or whether the initialization method by one of [Equation 20] to [Equation 24] other than [Equation 19] is also possible. It is possible to report to the base station through. Based on this, the base station uses the initialization method according to [Equation 19] through upper layer signaling for a terminal capable of using the initialization method according to Equation 20 to [Equation 24] or [Equation 19]. 20] to [Equation 24] may indicate whether to use the initialization method. At this time, if there is no upper layer signaling for the sequence initialization selection, the terminal may be promised to assume (use) the sequence initialization by [Equation 19] as the default.

Similarly, the base station uses the 1 bit included in the DCI to determine whether the UE uses sequence initialization according to [Equation 19] or one of [Equation 20] to [Equation 24] other than [Equation 19]. It is also possible to indicate whether to use the initialization method by.

Although the methods using CDM group index j in CSI-RS resource have been described in [Equation 20] to [Equation 24], the present invention is not limited thereto, and various modifications are possible.

For example, considering that up to four CDM groups can be transmitted in one OFDM symbol from the perspective of one CSI-RS resource, 'j' in [Equation 20] to [Equation 24] is defined as' j mod Can be modified to 4 '. Through this, if a large number of CDM groups in one CSI-RS resource is generated, such as when CDM-2 is set in 32-port CSI-RS and there are 16 CDM groups, generating a large number of unnecessary sequences Can be prevented.

As another example, in [Equation 20] to [Equation 24], the CDM group index 'j' may be replaced with a CSI-RS port index 'p'. Here, 'p' is the total number of P ports in the CSI-RS resource, {3000, 3001, ... , 3000 + P-1} or {0, 1,… , It is possible to use one of the values of P-1}. Through this, different sequences are used for each CSI-RS port within the CDM group, and interference randomization performance can be further improved.

If, in view of one CSI-RS resource, considering that up to eight CSI-RS ports can be transmitted to one OFDM symbol, 'j' in [Equation 20] to [Equation 24] is set to 'p mod 8 '. Here, 'p' is the CSI-RS port index in the CSI-RS resource. If there are a total of P ports in the corresponding CSI-RS resource, {3000, 3001… , 3000 + P-1} or {0, 1,… , It is possible to use one of the values of P-1}. Here, by modifying the 'j' to 'p mod 4', if a large number of ports in one CSI-RS resource, such as 32-port CSI-RS, is prevented from generating an unnecessarily large number of sequences. You can.

<Second Example>

In the second embodiment, an initialization method for generating a DMRS sequence is described. In the case of Rel-15 NR, the base station and the terminal use a sequence generator based on [Equation 1] and [Equation 5] and generate a sequence. At this time, in each OFDM symbol, use [Equation 25] below. Initialize the sequence.

[Equation 25]

Similar to the case of CSI-RS, in the case of [Equation 25], there is a risk of deteriorating the PAPR characteristic of the DMRS OFDM symbol by assigning the same sequence value to multiple DMRS ports. One way to solve this is to use different sequence initialization for each DMRS port (or for each DMRS CDM group).

For example, the base station and the terminal 1) DMRS port number (eg 1000, 1001, ..., 1011) or 2) assigned DMRS port order (allocated DMRS port order) p or 3) DMRS CDM group number (eg 0 , 1, 2,…) can be additionally used for sequence initialization. Method 1) or 3) uses fixed sequence initialization according to the actual DMRS port number regardless of DMRS allocation, and thus has the advantage of easier prediction of interference management. In the case of method 2), a limited number of terminals can be used. Considering that only the DMRS port is allocated, there is an advantage that the sequence initialization change can be minimized. In the following, for convenience of explanation, the DMRS indexes in the above methods 1), 2) or 3) are all referred to as p.

[Equation 20] is a method of determining the sequence initialization value by adding the DMRS port index p to the OFDM symbol position l. This feature allows DMRS ports in one OFDM symbol to use an RS sequence similar to DMRS ports of adjacent OFDM symbols, and facilitates reuse of an existing (eg, in Rel-15) RS sequence cell planning of a base station. Do it.

[Equation 26]

[Equation 21] is a method of determining the sequence initialization value by multiplying the OFDM symbol position l by the DMRS port index p. This has an effect of differently allocating intervals of sequence initialization values used by DMRS ports in one OFDM symbol over time, and can increase the randomness of reference signal interference.

[Equation 27]

[Equation 22] is the slot number

It is a method of determining the sequence initialization value by multiplying the DMRS port index p by. This has the effect of preventing DMRS ports from using the same sequence initialization value in one slot, which is easy to manage reference signal interference.

[Equation 28]

[Equation 23] is the scrambling ID term

It is a method of determining the sequence initialization value by adding the DMRS port index p to. This has the effect of preventing the DMRS ports from using the same sequence initialization value regardless of the time position of the DMRS OFDM symbol, which is easy to manage reference signal interference.

[Equation 29]

[Equation 24] is a method of determining a sequence initialization value by adding the DMRS port index p to the Rel-15 sequence initialization value. This allows DMRS ports in one OFDM symbol to use consecutive sequence initialization, and facilitates reuse of the base station's existing RS sequence cell planning (for example, in Rel-15).

Equation 30

[Equations 26] to [Equation 30] are examples for helping understanding of the second embodiment, and it is possible to apply other methods similar to the actual application without being limited thereto.

Meanwhile, one of [Equation 26] to [Equation 30] is not used alone, but can be used with [Equation 25] for backward compatibility. For example, the UE is capable of supporting only the initialization of the sequence by [Equation 25], or whether the initialization method by one of [Equation 26] to [Equation 30] other than [Equation 25] is also supported. It is possible to report to the base station through. Based on this, the base station uses the initialization method according to [Equation 25] through upper layer signaling for a terminal capable of using the initialization method according to Equation 26 to [Equation 30] or [Equation 26]. ] To [30] may indicate whether to use the initialization method. At this time, if there is no upper layer signaling for the sequence initialization selection, the terminal may be promised to assume (use) the sequence initialization by [Equation 25] as the default.

Similarly, the base station uses the 1 bit included in the DCI to determine whether the UE uses sequence initialization according to [Equation 19] or one of [Equation 20] to [Equation 24] other than [Equation 19]. It is also possible to indicate whether to use the initialization method by. At this time, the UE can be guaranteed to use only sequence initialization according to [Equation 19] for PDSCH or PUSCH scheduled by DCI format 0_0 or 0_1, which is a fallback mode.

<Third Example>

In the third embodiment, an initialization method for generating a CSI-RS sequence is described.

One of the main uses of CSI-RS (Channel Status Information Reference Signal) is for measuring mobility of a terminal, where the terminal can measure CSI-RS transmitted from neighboring cells as well as its own serving cell. .

If the CSI-RS sequence is initialized based on n _s that is not repeated within one frame, the UE can obtain the correct value of the CSI-RS sequence until it decodes the PBCH (Physical Broadcast Channel) of the neighboring cell. Difficult to grasp However, if the CSI-RS sequence is repeated in 5 ms units, that is, in half frame units, the UE performs CSI only by receiving a PBCH demodulation reference signal (DMRS) transmitting 3 bits of a least significant bit (LSB) among the SS / PBCH block index. -The RS sequence can be accurately known, and the advantage (effect) of not having to decode the PBCH of the neighboring cell can be obtained.

To this end, sequence generation and initialization may be used, and this will be described with reference to [Equation 31] below.

Equation 31

In Equation 31, M is 1) the number of CSI-RS ports included in one CSI-RS CDM group, or 2) the number of CSI-RS ports included in one CSI-RS resource, or 3) higher It may be a CSI-RS RE density that is set in a layer.

For example, when M is 1), M may be set to a higher layer up to 8, and in another example, when M is 2), M may be set to a maximum layer up to 32. This is to generate a long length gold sequence output in one CDM group or CSI-RS resource and use it properly by port.

System bandwidth in [Equation 31]

Is used, but when applied to other systems, it is possible to change to a different value such as the bandwidth of the bandwidth part (BWP) set and allocated to the terminal or the maximum bandwidth set for the terminal. At this time, in order to share the same sequence (sequence) between the terminals that are assigned to the BWP of different bands, the base station and the terminal first system bandwidth (or

) Based sequence (that is, the sequence is generated based on the absolute index of the PRB), and in actual transmission, only the sequence corresponding to the allocated band (that is, the band of the activated BWP) is set to be used ( Promise) is possible.

In the above-described embodiment, the system bandwidth information can be known to the terminal by various methods, for example, the terminal through a frequency offset value set based on the lowest (or highest) Synchronization Signal (SS) band. It is possible to recognize the beginning (or end) of the system bandwidth.

Equation 32

If, as in [Equation 32], a sequence initialization method similar to the LTE system is used as it is, as shown in [Table 3] and [Table 4], it can be expressed in various terms such as subcarrier spacing, numerology, etc. follow

The number of possible cases of possible Cinit by increasing

Can exceed dogs (in [Equation 32]

Is the slot number in one transmission frame (within a frame), l is the OFDM symbol number in the slot,

Is a CSI-RS ID (scrambling ID) to be set in the upper layer).

Therefore, it is prevented by using a modulo operation as shown in [Equation 33] below.

[Equation 33]

In [Equation 33]

Is a slot number in one transmission frame, l is an OFDM symbol number in a slot,

Is a CSI-RS ID (scrambling ID) that is set in an upper layer. Referring to [Equation 33], the terminal to receive the CSI-RS

It is necessary to know exactly, but in the case of an asynchronous network, the terminal

The case of unknown is generated. Therefore, it is possible to consider a change such as [Equation 34].

Equation 34

In [Equation 34]

Is a slot number in one transmission frame, l is an OFDM symbol number in a slot,

Is 0 ~ (

One of the values of -1) is a CSI-RS ID (scrambling ID) that is set in the upper layer,

Is the number of slots in one frame determined by the SCS as shown in Table 4. In addition, in [Equation 34], M is a variable for adjusting the sequence initialization repetition period, 1) defined as a fixed value, 2) determined by a higher layer setting value, or 3) implicit by other parameters Or 4) implicitly depending on the reference signal (RS) use.

In one embodiment, {M = 10 / sequence repetition period [ms]} is a representative example of defining M as a fixed value. Here, it is possible to define M = 2 for 5 ms repetition or M = 10 for 1 ms repetition.

In another embodiment, the M value may indicate one of several candidate values through higher layer signaling. For example, the base station may instruct the terminal to use one of {1, 2, 10} or {1, 2, 5, 10} as M.

If M is promised as a value changed by other parameters, M is an SCS value.

It is possible to change by parameters such as. for example,

In other words, if SCS = 15kHz or 30kHz is set, M = 10, and the sequence is repeated every 1 ms.

That is, when SCS = 60kHz or 120kHz or 240kHz is set, it is possible to make M = 2 and repeat the sequence every 5 ms. This takes into account that it is difficult to obtain timing information by PBCH DMRS when the SCS value is large, that is, 5 ms boundary information is obtained by the PBCH DMRS in the high frequency band, that is, when the SCS value is small, that is, in the low frequency band. will be.

It should be noted that different values can be mapped when the values of M according to the values are applied as examples.

In another embodiment, M may be determined according to the use of RS. For example, CSI-RS is set for tracking (or, when the upper layer parameter TRS-INFO of the CSI-RS is set to 'ON'), CSI-RS is beam management (beam management) Or (if CSI-RS is set for L1-RSRP reporting / computation) and / or CSI-RS is set for CSI acquisition (or CSI-RS connects to one or more reporting settings) If possible), the terminal may use a sequence initialization period of 10 ms assuming M = 1. As another example, if any CSI-RS is configured for mobility, the UE may use a sequence initialization period of 5 ms assuming M = 2. In this case, when the CSI-RS is configured for mobility, 1) the CSI-RS is associated / connected by the upper layer parameter RLM-CSI RS, or 2) the corresponding CSI-RS is the upper layer parameter CSI-RS-. Set by ResourceConfig-Mobility to CSI-RS-Resource-Mobility, or 3) one of various conditions, such as when serving cell timing cannot be used for neighbor cell SS and RS measurement because the upper layer parameter useServingCellTiming is set to Disabled or OFF. it means.

On the other hand, the above-described mapping of the M value for each RS use is an embodiment, and it is obvious that the system can be changed / applied when applied. In addition, although the above-described embodiments have been separately described for convenience of description, they are not mutually exclusive, and it is possible that two or more embodiments are simultaneously applied. For example, it is possible for M to be determined by being influenced by RS usage while being changed by the SCS value.

In one embodiment, if any CSI-RS is configured for tracking, CSI-RS is configured for beam management, or CSI-RS is configured for CSI acquisition, the UE sets M = 1. It is assumed that a sequence initialization period of 10 ms can be used (the M may be changed depending on the use of RS). In another embodiment, when CSI-RS is configured for mobility, the UE may determine M according to the SCS value applied to CSI-RS (eg,

In other words, if SCS = 15kHz or 30kHz is set, M = 10, and the sequence is repeated every 1 ms.

That is, when SCS = 60kHz or 120kHz or 240kHz is set, M = 2, and the sequence can be repeated every 5ms).

Through [Equation 34], the UE can perform PBCH of another cell even in an asynchronous network (for example, when serving cell timing is not available for neighbor cell SS and RS measurement because the upper layer parameter useServingCellTiming is set to Disabled or OFF). Without decoding (of the neighbor cell

Of the current cell without information

Based on) it is possible to receive CSI-RS of another cell.

The base station can use an additional CSI-RS sequence generation method similar to [Equation 34] other than the CSI-RS sequence generation method according to [Equation 33], and any CSI-RS sequence generation method to the UE. It is possible to tell if it has been used.

When two or more CSI-RS sequence generation methods are supported, a method for the base station to inform the UE which CSI-RS sequence generation method is used is: 1) CSI- selected by higher layer signaling such as RRC signaling; It is necessary to explicitly indicate the RS sequence generation method, 2) implicitly determine the CSI-RS sequence generation method according to the PDSCH transmission type, or 3) implicitly determine the CSI-RS sequence generation method according to the RS use. It is possible.

When the CSI-RS sequence generation method is indicated by RRC signaling, the base station may indicate one CSI-RS sequence generation method for all PDSCH (Physical Downlink Shared Channel) transmissions, but extends this to extend the PDSCH transmission type. It is obvious that different CSI-RS sequence generation methods can be indicated. Here, the PDSCH transmission type is divided according to slot-based scheduling (14 OFDM symbol based scheduling) or non-slot-based scheduling (2- / 4- / 7-OFDM symbol based scheduling), eMBB / mMTC / URLLC / Classification according to service type such as LAA, classification according to RNTI type applied to the corresponding PDSCH such as C-RNTI / P-RNTI / SI-RNTI, synchronous network (synchronous network, upper layer parameter useServingCellTiming is set to Enable or ON, and neighbor cells When serving cell timing can be used for SS and RS measurements), according to an asynchronous network (when serving cell timing is not available for neighbor cell SS and RS measurements because asynchronous network, upper layer parameter useServingCellTiming is set to Disabled or OFF). It should be noted that it can be used in various ways such as classification.

For example, in the case of a synchronous network (when serving cell timing is used to measure neighbor cell SS and RS when the upper layer parameter useServingCellTiming is set to Enable or ON), Equation 33 is applied, In the case of asynchronous network (when serving cell timing is not available for neighbor cell SS and RS measurement because the upper layer parameter useServingCellTiming is set to Disabled or OFF), CSI-RS for CSI acquisition / beam management / time-frequency tracking 33] is applied and another method similar to [Equation 34] having a sequence generation repetition period of 5 ms is applied to CSI-RS for mobility (ie, CSI-RS from another cell to support L3 mobility). By applying, it is possible to facilitate the mobility RS reception of the terminal.

Among the above-described embodiments, an embodiment related to an indication of a method for generating a sequence by higher layer signaling includes a method in which a base station provides one or more subframe numbers (SFN) or one or more SFN offsets to a terminal through higher layer signaling. For example, the UE is based on the subframe number (SFN) or one or more SFN offsets, CSI-RS for CSI acquisition / beam management / time-frequency tracking in [Equation 35] below.

And CSI-RS for mobility

It is possible to apply.

[Equation 35]

<Fourth Example>

In the fourth embodiment, another example of an initialization method for generating a DMRS sequence is described. In the case of Rel-15 NR, the base station and the terminal use a sequence generator based on [Equation 1] and [Equation 5] and generate a sequence. At this time, each OFDM symbol uses [Equation 36] below. You can initialize the sequence.

[Equation 36]

In the case of [Equation 36], there is a risk of deteriorating the PAPR characteristics of the DMRS OFDM symbol by assigning the same sequence value to multiple DMRS ports. One way to solve this is to use different sequence initialization for each DMRS CDM group.

For example, the base station and the terminal can additionally use the DMRS CDM group number (e.g. 0, 1, 2, ...) for sequence initialization. DMRS can have up to two DMRS CDM groups (CDM group # 0, CDM group # 1) in one DMRS OFDM symbol for DMRS type 1, depending on the type specified as the upper layer, and up to 3 for DMRS type 2 There may be DMDM CDM group (CDM group # 0, CDM group # 1, CDM group # 2). For example, through DMRS configuration information designated as a higher layer, the base station and the terminal may determine whether to use the DMRS CDM group number for sequence initialization of CDM group # 1 and CDM group # 2.

The base station according to an embodiment is capable of instructing whether the UE uses the DMRS CDM group number (e.g. 0, 1, 2, ...) for sequence initialization using higher layer signaling. At this time, the UE uses only sequence initialization that is not based on the CDM group number regardless of signaling whether to use the DMRS CDM group number-based sequence initialization for PUSCH or PDSCH scheduled by DCI format 0_0 or 1_0, which is a fallback mode, For PUSCH or PDSCH scheduled by other non-fallback mode DCI format (for example, DCI format 0_1 or 1_1), CDM group number (eg 0, according to signaling of whether to use the DMRS CDM group number-based sequence initialization) You can promise to decide whether to use sequence initialization using 1, 2, ...).

[Table 6]

On the other hand, referring to [Equation 36], the base station transmits two virtual cell IDs (

and

) And 1 bit with DCI

By indicating (0 or 1), it is possible to dynamically even one of the two virtual cell IDs described above. This is to enable DMRS port allocation as well as sequence scrambling to be dynamically changed when performing MU MIMO or cooperative communication (cooperative multi point operation, CoMP, multi-TRP) through multiple base stations.

At this time, in the case of type 1 DMRS (DMRS configuration type 1), it is possible to distribute two virtual cell IDs set through the upper layer one by one to the CDM group by using up to two DMRS CDM groups that can be allocated to the terminal. For example, the first virtual cell ID (

) Is assigned to the first CDM group (CDM group # 0) and the second virtual cell ID (

) Can be assigned to the second CDM group (CDM group # 1). DMRS port 1000, 1001, 1004, and 1005 belonging to the first CDM group use c_init such as [Equation 37], and DMRS port 1002, 1003, 1006, and 1007 belonging to the second CDM group are expressed as Equation 38. It means using c_init.

[Equation 37]

[Equation 38]

In [Equation 37] to [Equation 38]

Indicates the CDM group index and maintains the same notation in the following description. Equations 37 to 38 may be represented by a single equation such as Equation 39.

[Equation 39]

Meanwhile, when a DMRS sequence is generated according to [Equation 37] to [Equation 38] or [Equation 39], the DCI is

There may be a disadvantage that the effect of changing the sequence based on weakens. To overcome this

Depending on the value, modification such as changing the mapping between the CDM group and the virtual cell ID is possible. For example, the base station and the terminal

If indicated as 0, {CDM group # 0 is the first virtual cell ID (

) And the second virtual cell ID in CDM group # 1 (

Promise to map),

= 1, the second virtual cell ID in {CDM group # 0 (

) And the first virtual cell ID in CDM group # 1 (

It is possible to promise to map).

This is 1)

When = 0, DMRS ports 1000, 1001, 1004, and 1005 belonging to the first CDM group use c_init as in Equation 40, 2)

When = 0, DMRS ports 1002, 1003, 1006, and 1007 belonging to the second CDM group use c_init as in Equation 41, 3)

When = 1, DMRS ports 1000, 1001, 1004, and 1005 belonging to the first CDM group use c_init like Equation 42, and 4)

When = 1, DMRS ports 1002, 1003, 1006, and 1007 belonging to the second CDM group mean using c_init as in Equation 43.

 [Equation 40]

 [Equation 41]

 [Equation 42]

 [Equation 43]

[Equation 40] to [Equation 43] may be represented by a single equation such as [Equation 44].

[Equation 44]

[Equation 44]

Is the maximum number of CDM groups, that is, the part that needs to be modified according to the DMRS type.

, where w = 2 for DMRS configuration type 1 is possible.

Examples of [Equation 37] to [Equation 44] can be extended as follows for type 2 DMRS.

The first method is to set a total of 6 virtual cell IDs through a higher layer to enable selection of up to 3 CDM groups and 2 virtual cell IDs per CDM group. At this time, the six virtual cell IDs may include two virtual cell IDs previously set for release 15 DMRS. In one embodiment, the base station may 1) additionally set 6 virtual cell IDs separately from 2 virtual cell IDs for release 15 DMRS, but 2) add 2 virtual cell IDs for release 15 DMRS by reusing them. It is also possible to set four more cell IDs. For example, 6 virtual cell IDs {

,

,

,

,

,

}, The base station through DCI

When indicated as = 0, the terminal is the first 3 virtual cell IDs in CDM group # 0, # 1, # 2

,

,

Understand that each is assigned to generate a sequence,

If indicated as = 1, the terminal is later 3 virtual cell IDs in CDM group # 0, # 1, # 2

,

,

It is possible to understand that each is assigned to generate a sequence. The expression of the equation in this embodiment is similar to the examples of [Equation 37] to [Equation 44], and thus is omitted.

The second method is to extend and apply the method of DMRS type 1, the same method as DMRS type 1 is applied to the first two CDM group # 0 and # 1, but two additional virtual cell IDs are applied to the third CDM group # 2. By setting

It is a method of selecting one according to the value. According to an embodiment, the base station has two virtual cell IDs for release 15 DMRS used for CDM group # 0 and # 1 (

,

) And 2 virtual cell IDs used for CDM group # 2 (

,

) To total 4 virtual cell IDs can be set to the terminal. For example, the base station and the terminal

If indicated as 0, {CDM group # 0 is the first virtual cell ID (

), The second virtual cell ID in CDM group # 1 (

), And the third virtual cell ID in CDM group # 2 (

Promise to map),

= 1, the second virtual cell ID in {CDM group # 0 (

), The first virtual cell ID in CDM group # 1 (

), And the fourth virtual cell ID in CDM group # 2 (

It is possible to promise to map). Since the expression of the equation in this embodiment is similar to the examples of equations 37 to 44, it is omitted.

The third method is another example of extending the method of DMRS type 1, by setting a total of three virtual cell IDs

This is a method to determine the order in which virtual cell IDs are mapped to CDM groups # 0, # 1, and # 2 according to the values. According to an embodiment, the base station has two virtual cell IDs for release 15 DMRS (

,

) And 1 additional virtual cell ID (

) To set a total of 3 virtual cell IDs to the terminal. For example, the base station and the terminal

If indicated as 0, {CDM group # 0 is the first virtual cell ID (

), The second virtual cell ID in CDM group # 1 (

), And the third virtual cell ID in CDM group # 2 (

Promise to map),

When indicated as = 1, the above virtual cell ID mapping is cyclic shifted one by one, and the second virtual cell ID in (CDM group # 0) (

), The third virtual cell ID in CDM group # 1 (

), And the first virtual cell ID in CDM group # 2 (

It is possible to promise to map). An example of the mathematical expression of this embodiment is shown in Equation (45).

[Equation 45]

[Equation 45]

Is the maximum number of CDM groups, that is, the part that needs to be modified according to the DMRS type

, where w = 3 for DMRS configuration type 2 is possible.

Referring to the above-described embodiments, [Equation 46] may be considered as an integrated solution of DMRS configuration type 1 and type 2.

[Equation 46]

5 is a block diagram showing the structure of a base station according to an embodiment.

As illustrated in FIG. 5, a base station according to an embodiment may include a transceiver 510, a memory 520, and a processor 530. The processor 530, the transceiver 510, and the memory 520 of the base station may operate according to the communication method of the base station described above. However, the components of the base station are not limited to the above-described examples. For example, the base station may include more components or fewer components than the components described above. In addition, the processor 530, the transceiver 510, and the memory 520 may be implemented as a single chip. Also, the processor 530 may include at least one processor.

The transmitting and receiving unit 510 collectively refers to a base station receiving unit and a base station transmitting unit, and may transmit and receive signals to and from a terminal. The signal transmitted and received with the terminal may include control information and data. The transmitter / receiver 510 may be composed of an RF transmitter that up-converts and amplifies the frequency of the transmitted signal, an RF receiver that amplifies the received signal with low noise, and down-converts the frequency. However, this is only an embodiment of the transceiver 510, and the components of the transceiver 510 are not limited to the RF transmitter and the RF receiver.

In addition, the transmission / reception unit may receive a signal through a wireless channel, output the signal to the processor 530, and transmit a signal output from the processor 530 through a wireless channel.

The memory 520 may store programs and data necessary for the operation of the base station. In addition, the memory 520 may store control information or data included in a signal obtained from a base station. The memory 520 may be formed of a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media.

The processor 530 may control a series of processes so that the base station can operate according to the above-described embodiment of the present disclosure. For example, the transmission / reception unit 510 receives a data signal including a control signal transmitted by the terminal, and the processor 530 may determine the reception result of the control signal and data signal transmitted by the terminal. In one embodiment, the processor 530 determines the structure of the reference signal, generates configuration information of the reference signal to be delivered to the terminal, and based on the configuration information, CSI-RS (Channel State Information Reference Signal) or DMRS (DeModulation Reference) Signal) sequence, and can be controlled to transmit CSI-RS or DMRS to the terminal.

6 is a block diagram showing the structure of a terminal according to an embodiment.

As shown in FIG. 6, the terminal of the present disclosure may include a transceiver 610, a memory 620, and a processor 630. The processor 630, the transceiver 610, and the memory 620 of the terminal may operate according to the aforementioned communication method of the terminal. However, the components of the terminal are not limited to the above-described examples. For example, the terminal may include more components or fewer components than the aforementioned components. In addition, the processor 630, the transceiver 610, and the memory 620 may be implemented as a single chip (chip). In addition, the processor 630 may include at least one processor.

The transmitting and receiving unit 610 collectively refers to a receiving unit of the terminal and a transmitting unit of the terminal, and can transmit and receive signals to and from the base station. Signals transmitted and received by the base station may include control information and data. To this end, the transmitter / receiver 610 may be composed of an RF transmitter for up-converting and amplifying the frequency of the transmitted signal, an RF receiver for low-amplifying the received signal and down-converting the frequency. However, this is only one embodiment of the transceiver 610, and the components of the transceiver 610 are not limited to the RF transmitter and the RF receiver.

Also, the transceiver 610 may receive a signal through a wireless channel, output the signal to the processor 630, and transmit a signal output from the processor 630 through a wireless channel.

The memory 620 may store programs and data necessary for the operation of the terminal. In addition, the memory 620 may store control information or data included in a signal acquired by the terminal. The memory 620 may be composed of a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media.

The processor 630 may control a series of processes so that the terminal operates according to the above-described exemplary embodiment. For example, the transmission / reception unit 610 receives a data signal including a control signal, and the processor 630 may determine a reception result for the data signal. In one embodiment, the processor 630 may control to receive a reference signal from a base station and interpret a method of applying the reference signal. In addition, it may be controlled to transmit the reference signal through the transceiver 610.

Methods according to embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

When implemented in software, a computer readable storage medium or computer program product storing one or more programs (software modules) may be provided. One or more programs stored in a computer readable storage medium or computer program product are configured to be executable by one or more processors in an electronic device. The one or more programs include instructions that cause an electronic device to execute methods according to embodiments described in the claims or specification of the present disclosure.

Such programs (software modules, software) include random access memory, non-volatile memory including flash memory, read only memory (ROM), and electrically erasable programmable ROM. (EEPROM: Electrically Erasable Programmable Read Only Memory), magnetic disc storage device (CD-ROM: Compact Disc-ROM), digital versatile discs (DVDs) or other forms It can be stored in an optical storage device, a magnetic cassette. Alternatively, it may be stored in a memory composed of a combination of some or all of them. Also, a plurality of configuration memories may be included.

In addition, the program may be accessed through a communication network composed of a communication network such as the Internet, an intranet, a local area network (LAN), a wide LAN (WLAN), or a storage area network (SAN), or a combination thereof. It may be stored in an attachable storage device. Such a storage device may connect to a device performing an embodiment of the present disclosure through an external port. In addition, a separate storage device on the communication network may access a device that performs embodiments of the present disclosure.

In the specific embodiments of the present disclosure described above, elements included in the present disclosure are expressed in singular or plural according to the specific embodiments presented. However, the singular or plural expressions are selected to suit the circumstances presented for convenience of description, and the present disclosure is not limited to the singular or plural elements, and the singular or plural elements may be used in the singular or the singular. Even expressed components may be composed of a plurality.

On the other hand, the embodiments disclosed in the present specification and drawings are merely to provide a specific example to easily describe the technical content of the present disclosure and to understand the present disclosure, and are not intended to limit the scope of the present disclosure. That is, it is obvious to those skilled in the art to which other modifications based on the technical spirit of the present disclosure can be practiced. In addition, each embodiment can be operated in combination with each other as necessary. For example, portions of one embodiment of the present disclosure and parts of another embodiment may be combined with each other. Further, the embodiments may be implemented in other systems, for example, LTE systems, 5G or NR systems, and other modifications based on the technical spirit of the above-described embodiment.

Claims (15)

1. In a method for a terminal to transmit and receive signals in a wireless communication system,

   Transmitting capability information of a terminal regarding sequence initialization of a demodulation reference signal (DMRS) to a base station;

   Receiving DMRS configuration information determined based on capability information of the terminal from the base station; And

   And receiving the DMRS from the base station based on the DMRS configuration information.

   The DMRS is generated based on a sequence initialization parameter determined based on a code division multiplexing (CDM) group identifier included in the DMRS configuration information.
2. The method of claim 1, wherein the sequence initialization parameter,

   A parameter corresponding to the CDM group identifier and the CDM group identifier

   

   Is determined on the basis of,

   remind

   

   The initializing parameter of each of the different CDM group identifiers, which is determined to be the same, has a different value based on the CDM group identifier.
3. The method of claim 2, which is a parameter corresponding to the CDM group identifier.

   

   Is,

   It is determined by each CDM group identifier using the parameter value obtained through DCI.
4. According to claim 1, Sequence initialization parameter determined based on the DCM group identifier,

   Method that applies to both DMRS Type 1 and DMRS Type 2.
5. According to claim 1,

   The DMRS is generated based on a sequence initialization parameter determined based on the CDM group identifier in the case of a PUSCH or a PDSCH scheduled by a DCI format other than DCI format 0_0 or DCI format 1_0.
6. In a method for transmitting and receiving signals from a base station in a wireless communication system,

   Receiving capability information of a terminal on sequence initialization of a demodulation reference signal (DMRS) from the terminal;

   Transmitting DMRS configuration information determined based on the capability information of the terminal to the terminal; And

   And transmitting the DMRS to the terminal,

   The DMRS is generated based on a sequence initialization parameter determined based on a code division multiplexing (CDM) group identifier included in the DMRS configuration information.
7. The method of claim 6, wherein the sequence initialization parameter,

   A parameter corresponding to the CDM group identifier and the CDM group identifier

   

   Is determined on the basis of,

   remind

   

   The initializing parameter of each of the different CDM group identifiers, which is determined to be the same, has a different value based on the CDM group identifier.
8. The method of claim 6, wherein the sequence initialization parameter determined based on the DCM group identifier,

   Method that applies to both DMRS Type 1 and DMRS Type 2.
9. In the terminal for transmitting and receiving a signal in a wireless communication system,

   Transceiver; And

   Including a processor,

   The processor,

   Transmits the capability information of the terminal regarding the sequence initialization of the DMRS (demodulation reference signal) to the base station,

   DMRS configuration information determined based on the capability information of the terminal is received from the base station,

   Control the transceiver to receive the DMRS from the base station based on the DMRS configuration information,

   The DMRS is generated based on a sequence initialization parameter determined based on a code division multiplexing (CDM) group identifier included in the DMRS configuration information.
10. 10. The method of claim 9, The sequence initialization parameter,

    A parameter corresponding to the CDM group identifier and the CDM group identifier

    

    Is determined on the basis of,

    remind

    

    The initializing parameter of each of the different CDM group identifiers, which is determined to be the same, has a different value based on the CDM group identifier.
11. 11. The method of claim 10, It is a parameter corresponding to the CDM group identifier

    

    Is,

    The terminal is determined for each CDM group identifier using the parameter value obtained through DCI.
12. The sequence initialization parameter according to claim 9, which is determined based on the DCM group identifier,

    A terminal that is applied to both DMRS type 1 and DMRS type 2.
13. In the base station for transmitting and receiving signals in a wireless communication system,

    Transceiver; And

    Including a processor,

    The processor,

    Receiving capability information of the terminal regarding sequence initialization of a demodulation reference signal (DMRS) from the terminal,

    DMRS configuration information determined based on the capability information of the terminal is transmitted to the terminal,

    Control the transmitting and receiving unit to transmit the DMRS to the terminal,

    The DMRS is generated based on a sequence initialization parameter determined based on a code division multiplexing (CDM) group identifier included in the DMRS configuration information.
14. The method of claim 9, wherein the sequence initialization parameter,

    A parameter corresponding to the CDM group identifier and the CDM group identifier

    

    Is determined on the basis of,

    remind

    

    The base station, wherein the initialization parameter of each of the different CDM group identifiers determined to be the same has a different value based on the CDM group identifier.
15. The sequence initialization parameter of claim 13, which is determined based on the DCM group identifier,

    Base station, which applies to both DMRS type 1 and DMRS type 2.

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