KR20210034834A - Method and apparatus for dynamically controlling SRS based on UE Capability - Google Patents

Abstract

The present invention relates to an SRS control method and apparatus therefor. According to one embodiment of the present invention, a sounding reference signal (SRS) control method for a terminal which is connectable to a non-stand-alone (NSA) 5G network, includes the following steps of: setting a signaling radio bearer (SRB) by performing an initial connection procedure with a first base station; receiving a terminal capability query message from the first base station through the SRB; identifying a standard version applied to the network based on an information element (IE) included in the terminal capability query message; and transmitting a terminal capability information message including CA-ParameterNR-v1550 IE to the first base station if the identified standard version is no less than a reference version.

Description

TECHNICAL FIELD The method and apparatus for dynamically controlling SRS based on UE capability

The present invention relates to a mobile communication technology, and in detail, to an SRS control method capable of dynamically controlling a sounding reference signal (SRS) start offset based on terminal capability information, and an apparatus and system therefor.

The content described in this section merely provides background information on the present embodiment and does not constitute the prior art.

A mobile communication service provider can separate and operate a core network for each service for the purpose of ensuring service quality and easy management according to network expansion.

^{3GPP (3 rd Generation Partnership Project)} 4G (4 th Generation) communication system, LTE (Long Term Evolution) is in accordance with increases in demand since the commercialization of data traffic explosion 3GPP is the 5G (5 ^th more improved 5. Communication system Generation) NR (New Radio) system has been standardized.

In the initial commercialization stage of NR, a 5G standard system, mobile operators are providing 5G services by constructing a Non Stand Alone (NSA) system to support both the existing LTE service and NR.

In order to achieve a high data rate, the 5G system is considering implementation in an ultra-high frequency (mmWave) band (for example, a 60 gigabyte (60 GHz) band).

In order to mitigate the path loss of radio waves in the ultra-high frequency band and increase the propagation distance of radio waves, in 3GPP, beamforming technology and massive multi-input multi-output (massive MIMO) technology in connection with 5G systems , Full Dimensional MIMO (FD-MIMO) technology, array antenna technology, analog beam-forming technology, and large scale antenna technology are discussed.

In addition, 3GPP members and related industries include Hybrid FSK and QAM Modulation (FQAM) and Sliding Window Superposition Coding (SWSC), which are advanced coding modulation (ACM) methods, and Filter Bank Multi Carrier (FBMC), which is an advanced access technology. , NOMA (Non Orthogonal Multiple Access) and SCMA (sparse code multiple access) are being developed.

The LTE system uses a reference signal for channel estimation and scheduling.

The reference signal can be largely divided into a downlink reference signal and an uplink reference signal.

The downlink reference signal is a reference signal transmitted from the base station to a specific terminal or within a cell, and the uplink reference signal is a reference signal transmitted from the terminal to the base station.

The downlink reference signal in the LTE system includes a discovery reference signal (DRS), and the DRS is a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and cell specific. It includes a cell-specific reference signal (CRS) that is a reference signal.

The uplink reference signal is largely divided into a demodulation reference signal (DM-RS) and a sounding reference signal (SRS).

Hereinafter, the NR reference signal will be described.

As described above, the LTE system uses a cell-specific RS (CRS), which is a downlink reference signal that can be referred to as a kind of “one size fits all”. However, the use of CRS is a very energy-inefficient method while limiting the flexibility of network configuration. In addition, the CRS is difficult to apply to a high frequency region of 6 GHz or higher and is not suitable for a MIMO system using a plurality of antennas.

Therefore, in order to compensate for these shortcomings, the NR system guarantees stable tracking performance and obtains synchronization, TRS (Tracking RS), DM-RS (DeModulation RS) and CSI-RS (Channel Status Information RS) for channel estimation, and high-frequency By introducing a new reference signal (RS) called PT-RS (Phase Tracking RS) for phase noise compensation of the band, it is possible to cope with different frequency bands and various scenarios.

In addition, signals such as CSI-RS and SRS are designed to support transmission/reception beam switching for beam-based communication.

Currently, the 5G standard is still being maintained within the 3GPP international standard.

The 3GPP meets four times a year, and the standard version is updated every three months.

Even after the official 5G primary standard (Release 15) was officially released in June 2018, standardization members and companies are continuing maintenance by finding errors in the standard.

In particular, in the case of Korea, which started commercialization of 5G as quickly as possible, serious errors may occur if the standard version applied to the network and the standard version applied to the terminal are different in the presence of standard errors.

Whenever the standard version reflecting the actual error correction is released, it takes a lot of time and cost to update the versions of all terminals to the latest version at once.

Therefore, in the initial stage of commercialization, it is important to provide a mobile communication system that minimizes the occurrence of errors by adaptively performing exception processing according to the terminal version-that is, terminal capability.

The present invention has been devised to solve the problems of the prior art, and an object of the present invention is to provide an SRS control method and devices therefor.

As an embodiment, another object of the present invention is to provide an SRS control method and apparatuses for the same capable of dynamically controlling an SRS start offset based on terminal capability information.

As an embodiment, another object of the present invention is to provide an SRS control method and devices for preventing an error caused by inconsistency between standard versions of SRS start offset definitions.

As an embodiment, another object of the present invention is to identify a standard version applied to a 5G terminal in a network and adaptively set an SRS start offset according to the identified version, thereby preventing communication performance degradation, and an SRS control method and apparatus therefor To provide them.

The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems that are not mentioned will be clearly understood by those of ordinary skill in the technical field to which the present invention belongs from the following description. I will be able to.

The present invention can provide an SRS control method and devices therefor.

A method of controlling a Sounding Reference Signal (SRS) in a terminal capable of accessing a Non Stand Alone (NSA) 5G network according to an embodiment of the present invention is to set a Signaling Radio Bearer (SRB) by performing an initial access procedure with a first base station. Receiving a terminal capability query message from the first base station through the step and the SRB, and identifying a standard version applied to the network based on an information element (IE) included in the terminal capacity query message; and If the identified standard version is greater than or equal to the reference version, transmitting a terminal capability information message including the CA-ParameterNR-v1550 IE to the first base station.

As an example, when the uecapabilityenquiry-v1550 IE is included in the terminal capability query message, the terminal may determine that the standard version applied to the network is greater than or equal to the reference version.

As an example, the CA-ParameterNR-v1550 IE may include an aperiodic-CSI-diffSCS field indicating whether the terminal supports triggering of aperiodic Channel State Indicator-Reference Signal (CSI-RS).

As an example, the aperiodic-CSI-diffSCS field value may be set to “Supported”.

As an example, the terminal may be a 5G terminal, and the first base station may be a 4G Long Term Evolution (LTE) base station.

As an example, the terminal capability information message may be transmitted to a second base station through the first base station, and the second base station may be a 5G NR (New Radio) base station.

In an embodiment, the second base station identifies the standard version applied to the terminal based on the IE included in the terminal capability information message, compares the standard version applied to the terminal with the reference version, and SRS start position change mode Can be determined.

For example, if the standard version applied to the terminal is greater than or equal to the reference version, the SRS start position change mode may be determined as the first mode.

_{In an embodiment, in the first mode, N shift, which} is a start offset of the SRS in a carrier component (CC), may be smaller than _{a start offset BWP start} of a band-wide part (BWP) through which the SRS is transmitted.

For example, if the standard version applied to the terminal is smaller than the reference version, the SRS start position change mode may be determined as the second mode.

For example, in the second mode, the N _shift may be greater than or equal to the BWP _start.

_{In an embodiment, the reference point of the BWP start} corresponding to the first to second modes is Point A, which is a starting point of 5G radio resources, and _{the reference point of N shift} corresponding to the first mode is a starting point of the CC, and the first The reference point of the _{N shift} corresponding to the 2 mode may be the Point A.

A method for controlling a Sounding Reference Signal (SRS) in a system including a 4G Long Term Evolution (LTE) base station and a 5G NR (New Radio) base station according to another embodiment of the present invention is an initial access procedure for the 4G LTE base station with a 5G terminal. Performing the step of setting a Signaling Radio Bearer (SRB), and the 4G LTE base station transmitting a terminal capability query message to the 5G terminal through the SRB, and the 4G LTE base station transmitting a terminal capacity query message from the 5G terminal. Receiving a ruty information message and transmitting it to the 5G NR base station, and the 5G NR base station identifying a standard version applied to the terminal based on an information element (IE) included in the terminal capability information message, and the terminal It may include the step of determining the SRS start position change mode by comparing the standard version applied to the reference version.

For example, when the CA-ParameterNR-v1550 IE is included in the terminal capability information message, the 5G NR base station may determine the SRS start position change mode as the first mode.

As an example, when the terminal capability query message includes the uecapabilityenquiry-v1550 IE, the 5G terminal determines that the standard version applied to the system is equal to or greater than the reference version, and the terminal including the CA-ParameterNR-v1550 IE Capability information message can be transmitted.

In an embodiment, the CA-ParameterNR-v1550 IE includes an aperiodic-CSI-diffSCS field indicating whether the terminal supports triggering of aperiodic Channel State Indicator-Reference Signal (CSI-RS), and the aperiodic- The CSI-diffSCS field value may be set to “Supported”.

As an example, when the CA-ParameterNR-v1550 IE is not included in the terminal capability information message, the 5G NR base station may determine the SRS start position change mode as the second mode.

_{In an embodiment, in the first mode, N shift, which} is a start offset of the SRS in a carrier component (CC), may be smaller than _{a start offset BWP start} of a band-wide part (BWP) through which the SRS is transmitted.

For example, in the second mode, the N _shift may be greater than or equal to the BWP _start.

_{In an embodiment, the reference point of the BWP start} corresponding to the first to second modes is Point A, which is a starting point of 5G radio resources, and _{the reference point of N shift} corresponding to the first mode is a starting point of the CC, and the first The reference point of the _{N shift} corresponding to the 2 mode may be the Point A.

Another embodiment of the present invention may provide a recording medium in which a program for executing the above-described SRS control method is recorded.

The aspects of the present invention are only some of the preferred embodiments of the present invention, and various embodiments reflecting the technical features of the present invention will be described in detail below by those of ordinary skill in the art. It can be derived and understood on the basis of.

The effect of the method and apparatus according to the present invention will be described as follows.

As an embodiment, the present invention has an advantage of providing an SRS control method and apparatuses for dynamically controlling an SRS start offset based on terminal capability information.

As an embodiment, the present invention has an advantage of providing an SRS control method and devices for preventing an error caused by inconsistent SRS start offset definitions between standard versions.

As an embodiment, the present invention identifies a standard version applied to a 5G terminal in a network, and adaptively sets an SRS start offset according to the identified version, thereby providing an SRS control method and devices for preventing communication performance degradation. There is this.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings are provided to aid understanding of the present invention and provide embodiments of the present invention together with a detailed description. However, the technical features of the present invention are not limited to a specific drawing, and features disclosed in each drawing may be combined with each other to constitute a new embodiment.
1 is a block diagram of a mobile communication system according to an embodiment.
2 is a diagram illustrating a structure of an SA and NSA (EN-DC) system supporting the use of 5G NR according to an embodiment.
3 is a diagram illustrating a detailed structure of a 5G NSA system according to an embodiment.
4 is a flowchart illustrating a terminal access procedure according to an embodiment.
5 is a diagram for explaining the structure of a UE Capability Inquiry message according to an embodiment.
6 is a diagram for explaining the structure of a UE Capability Information message according to an embodiment.
7 is a diagram illustrating a method of setting an SRS start offset according to an embodiment.
8 is a diagram for describing a method of setting an SRS start offset according to another embodiment.
9 is a flowchart illustrating an SRS control method in an NSA system according to an embodiment.

Hereinafter, an apparatus and various methods to which embodiments of the present invention are applied will be described in more detail with reference to the drawings. The suffixes "module" and "unit" for constituent elements used in the following description are given or used interchangeably in consideration of only the ease of writing the specification, and do not themselves have a distinct meaning or role from each other.

In the description of the embodiment, in the case of being described as being formed on the “top (top) or bottom (bottom)” of each component, the top (top) or bottom (bottom) is that the two components are in direct contact with each other, or It includes all of the one or more other components formed by being disposed between the two components. In addition, when expressed as "upper (upper) or lower (lower)", the meaning of not only an upward direction but also a downward direction based on one component may be included.

1 is a diagram illustrating a structure of a mobile communication network according to an embodiment.

The mobile communication network according to the present invention may be configured based on the 4G standard 3GPP LTE (Long Term Evolution) and/or the 5G standard NR (New Radio), but this is only one embodiment, and the 4G standard and the 5G It can be configured to interwork with devices of a network other than the network element defined in the standard-for example, an IoT network.

Referring to FIG. 1, a mobile communication network according to an embodiment includes User Equipment (UE) 10, evolved Node B (eNB, 20), Serving Gateway (S-GW) 30, and Packet Data Network Gateway (P-GW) 40. ), MME (Mobility Management Entity, 50), HSS (Home Subscriber Server, 60), SPR (Subscriber Profile Repository, 70), OFCS (Offline Charging System, 80), OCS (Online Charging System, 90), PCRF (Policy and Charging Rule Function, 100).

The UE 10 is a user terminal conforming to the LTE and/or NR standard, and may connect the LTE Uu interface 15 with the eNB 20. Here, the LTE Uu interface 15 is a wireless interface and defines a control plane for transmitting and receiving a control message and a user plane for providing user data.

The UE 10 according to an embodiment may also interwork with gNB, which is a base station supporting the NR standard, or en-gNB, which is a base station supporting both LTE and NR standards.

The eNB 20 is a device that provides a radio interface to the UE 10 and provides radio resource management functions such as radio bearer control, radio admission control, dynamic radio resource allocation, load balancing, and inter-cell interference control. do.

S-GW (30) is the end of the E-UTRAN (Evolved Universal Terrestrial Radio Access Network) and Evolved Packet Core (EPC), the anchoring point (Anchoring point) when handover between eNBs (20) and handover between 3GPP systems do. Here, the E-UTRAN is composed of at least one eNB (20), and the EPC is composed of S-GW (30), P-GW (40) and MME (50).

The P-GW 40 connects the UE 10 with an external PDN (Packet Data Network) 110 and performs a packet filtering function.

In addition, the P-GW 40 allocates an IP address to the UE 10 and operates as a mobility anchoring point during handover between the 3GPP system and the non-3GPP system.

In particular, the P-GW (40) receives the PCC (Policy and Charging Control) rule from the PCRF (100), applies it to the service flow, and provides a charging function for each UE (10) / Service Date Flow (SDF). do.

The MME 50 provides an access control function for network connection of the UE 10, a network resource allocation function, a tracking function, a paging function, a roaming function, a handover function, etc. can do.

The MME 50 may manage a plurality of eNBs 20 and select a gateway by performing predetermined signaling for handover to an existing 2G/3G network.

In addition, the MME 50 may perform an authentication and security setting procedure for the accessing UE 10 in conjunction with the HSS 60, and may manage location information for idle terminals.

The MME 50 may obtain an authentication vector from the HSS 60 and perform mutual authentication with the UE 10 using the authentication vector. When the authentication procedure is completed, the MME 50 may set a security key for security between the UE 10 and the MME 50.

Another function of the MME 50 will become clearer through the description of the drawings to be described later.

The HSS 60 is a database in which a subscriber profile is stored, and provides user authentication information and a user profile to the MME 50.

The SPR 70 provides subscriber and subscription-related information to the PCRF 100, and the PCRF 100 generates a subscriber-based PCC rule using the subscriber and subscription-related information.

OFCS (80) provides charging information based on CDR (Charging Data Record).

The OCS 90 provides a billing function based on volume, time, and event through real-time credit control.

The PCRF 100 is an entity that performs policy and billing control and provides a policy control decision and billing control function. The PCC rule generated by the PCRF 100 is transmitted to the P-GW 40.

The PCRF 100 and the P-GW 40 according to the embodiment may interwork with an IP Multimedia Subsystem (IMS) network that provides various IP services of mobile operators.

Hereinafter, an interface between elements constituting an LTE network will be briefly described.

The LTE-Uu 15 provides a control plane and a user plane as a radio interface between the UE 10 and the eNB 20.

The S1-U 25 is an interface between the eNB 20 and the S-GW 30 and provides a user plane. At this time, GTP tunneling for each bearer is provided.

The S5 (35) is an interface between the S-GW (30) and the P-GW (40), and provides a control plane and a user plane. At this time, the user plane provides GTP tunneling for each bearer, and the control plane provides GTP tunnel management.

The SGi 45 defines a user plane and a control plane as an interface between the P-GW 40 and the PDN 110. IETF-based IP packet forwarding protocol is used in the user plane, and protocols such as DHCP and RADIUS/Diameter are used in the control plane.

S11 (55) is an interface between the MME (50) and the S-GW (30), the control plane is defined, and GTP tunneling is provided per bearer.

The X2 65 is an interface between two eNBs 20 or two base stations supporting different radio access technologies (RATs), and provides a control plane and a user plane. In the control plane, the X2-AP protocol is used, and in the user plane, GTP (GPRS Tunneling Protocol) tunneling is provided per bearer for data forwarding during X2 handover.

S6a (75) is an interface between the HSS (60) and the MME (50) is provided with a control plane, and is used to exchange UE subscription information and authentication information.

Gx (85) is an interface between the PCRF (100) and the P-GW (40), a control plane is defined, and is used to deliver a policy control rule and billing rule for QoS (Quality of Service) policy and billing control. .

Sp (95) is an interface between the SPR (70) and PCRF (100), a control plane is defined, and is used to deliver a user profile.

Gz 105 is an interface between the OFCS 80 and the P-GW 40, a control plane is defined, and is used for CDR transmission from the P-GW 40 to the OFCS 80.

Gy (115) is an interface between the OCS (90) and the P-GW (40), a control plane is defined, and is used for real-time credit (Credit) control information exchange.

The S1-AP 125 is an interface between the eNB 20 and the MME 50, and a control plane is defined, and is used for exchanging control information for mobility management.

FIG. 2 is a diagram illustrating a structure of an SA and NSA (EN-DC) system supporting the use of 5G NR according to an embodiment.

In the process of discussing the 5G structure at the general meeting of the 3GPP standards group, the demand to satisfy telecommunications operators in countries with rapid commercialization demand before 2020 and that it takes time to research and create standard technologies that can create new services. A request was made.

In the process of discussing these two conflicting demands, various post-structural security were discussed, and as a result of the discussion, a new NR (New Radio) technology for operators who want to quickly commercialize was used together with the existing LTE system to simultaneously use LTE coverage and NR coverage. A 　Non Standalone (NSA) 　 structure (FIG. 2(b)) and a Stand Alone (SA) 　 structure (FIG. 2(a)) providing only NR coverage were introduced.

The following three types of base station types may be defined in the SA system and the NSA system supporting the use of 5G NR of FIG. 2.

1) eNB: A base station used in an LTE system that supports interworking between LTE technology and EPC (Enhanced Packet Core).

2) gNB: Next-generation base station that supports interworking with NR technology and 5G Core

3) en-gNB: A new type of base station that supports interworking with NR technology and 5G Core, and at the same time interlocks with the LTE system core 　EPC and eNB

Of the three base station types, gNB is used only in the 5G SA structure, as shown in FIG. 2A.

This is because in the 5G SA structure, the UE uses only the resources of the gNB controlled by the NR technology.

In contrast, the UE in the 5G NSA structure uses not only the resources of the eNB supporting LTE technology, but also the resources of the en-gNB supporting NR technology while interworking with the eNB and EPC.

As shown in (b) of FIG. 2, a technology in which a terminal supporting one or more RX/TX simultaneously uses a resource controlled by one or more base stations is called Dual Connectivity (DC).The 5G NSA structure is DC defined by the 3GPP standard organization. It is based on technology.

3 is a diagram illustrating a detailed structure of a 5G NSA system according to an embodiment.

3 is a diagram illustrating a detailed structure of a 5G NSA system according to an embodiment.

The 5G NSA structure in the current 3GPP standard not only supports the use of NR in the Master Node (MN) or Secondary Node (SN), but also supports the use of the 5G Core or EPC for the core network.

The standard is defined to support various combinations of NSA structures, but in reality, in the case of a telecommunications operator using an LTE system composed of EPC and LTE macro base stations as a nationwide network, the structure of the combination that utilizes the existing LTE system to the maximum is fast 5G. It is being considered for commercialization.

As an example, the 5G NSA structure may be the structure of FIG. 4 in which the EPC of the LTE system is used as a core network, the eNB, which is an LTE base station, is used as the MN, and the en-gNB, which is an NR base station, is used as the SN.

An eNB operating as an MN can relay the transmission and reception of NAS (Nan Access Stratum) messages between the MME and the UE by creating an S1-MME control connection with the control entity MME of the EPC, which is the core of the LTE system.

The NAS layer is the uppermost layer of the control plane and can transmit and receive control messages between the MME and the UE. NAS messages include Mobility Management Messages such as location registration messages and handover messages, Session Management Messages related to session establishment and termination, and authentication and security related messages related to subscriber authentication and message security. Can include.

In addition, the eNB may create a radio resource control (RRC) connection with the UE using LTE radio technology, and manage the RRC state based on the RRC connection.

The en-gNB operating as an SN does not participate in the control connection related to the EPC and relaying of NAS messages, but can only participate in the additional data connection for transmitting and receiving high-capacity data.

The en-gNB, which transmits and receives data through an additional data connection, can transmit and receive data with the EPC using one of the following two paths, unlike the eNB, which is an MN.

The first path may be a PGW/SGW<-->eNB<-->en-gNB connection path for transmitting and receiving data through an eNB.

In this path, the eNB, the MN, acts as a split node that divides the first data that is directly sent to the UE using LTE radio resources and the second data that transmits data to the UE using NR resources through en-gNB. You can do it.

The second path is a PGW/SGW<-->en-gNB connection path that transmits and receives data directly to and from the PGW/SGW.

In this path, the SGW may serve as a split node that divides the first data transmitted and received with the UE through the eNB and the second data transmitted and received with the UE through the en-gNB.

Which one of the above two connection paths is used for data transmission/reception between the SN and the EPC may be determined according to a choice of a person skilled in the art.

4 is a flowchart illustrating a terminal access procedure according to an embodiment.

4, the UE 410 receives a system information message from the eNB 420 and transmits a random access channel (RACH) message according to the received system information message to perform an LTE RRC connection setup procedure. Can be started (S401). Here, the system information may be composed of one MIB (Master Information Block) and a plurality of SIB (System Information Block).

The description of the MIB and SIB is replaced by the content disclosed in 3GPP TS 36.331.

When the LTE RRC connection setup procedure is completed, a signaling radio bearer (SRB) capable of transmitting and receiving a control message is set between the UE 410 and the eNB 420.

The UE 410 may transmit an Attach Request message to the MME 430 using the configured SRB (S402).

At this time, the LTE eNB 420 does not set up a default radio bearer (DRB) with an NR link while performing the initial access procedure.

The UE 410 and the MME 430 may perform authentication and security procedures with the MME 430 through a predetermined non-access stratum (NAS) message (S403). Here, the NAS message collectively refers to a control message exchanged between the UE 410 and the MME 430.

Upon completion of the authentication and security procedure, the MME 430 may transmit an Initial Context Setup Request Message to the eNB 420.

The eNB 420 may transmit a UE Capability Inquiry message to the UE 410 (S404).

The UE 410 may perform a measurement procedure according to the previously received system information, generate a measurement report message, and transmit it to the MME 430.

The MME 430 may determine whether the UE 410 is in NR coverage through the measurement report message.

The terminal 410 may identify a Radio Access Technology (RAT) type, generate a UE Capability Information message according to the identified RAT type, and transmit it to the MME 430 (S405).

Here, the terminal capacity information may include NR capacity information of the terminal and/or existing LTE capacity information.

The UE 410 and the eNB 420 may set a radio bearer (RB) for user data transmission and reception through a predetermined LTE RRC connection reconfiguration procedure (S406).

When the RB is set up, the MME 430 may transmit an Attach Accept message and an Activate Default Bearer Request message to the UE 410 (S407).

After activating the default bearer, the UE 410 may transmit an Attach Complete message and an Activate Default Bearer Context Accept message to the MME 430 (S408).

When the UE 410 is an NSA 5G terminal, the UE 410 basically initiates an initial access procedure through the LTE eNB 420 as shown in FIG. 4 to complete the RRC connection setup, and the RRC connection setup is completed. In the LTE eNB (420) receives a UE Capability Inquiry message and provides the terminal capability information to the MME (430).

In this case, the UE 410 may transmit not only existing LTE capability information but also NR capability information in order to receive not only LTE service but also NR service.

5 is a diagram for explaining the structure of a UE Capability Inquiry message according to an embodiment.

As shown in FIG. 5, the UE Capability Inquiry message may include at least one version information 510 as well as RAT type information 520 that can be provided by a corresponding network.

Referring to reference number 510, the UE Capability Inquiry message may include IE for each version so that added functions for each released version can be identified.

For example, reference numeral 510 shows that the network can support V1510, V1530, and V1550.

Here, V1550 is the latest version applied to the network, and means 3GPP Release 15.5.0.

As the 3GPP standard specification is revised, the version included in the UE Capability Inquiry message may be added.

The UE may identify the standard version and RAT type that can be provided in the connected network through the UE Capability Inquiry message.

6 is a diagram for explaining the structure of a UE Capability Information message according to an embodiment.

Referring to FIG. 6, a UE Capability Information message is transmitted from a UE to a network-eg, E-UTRAN (LTE base station)- in an acknowledgment mode (AM) through an SRB.

The UE Capability Information message is a NAS message that is transmitted to the MME by mapping a dedicated control channel, a dedicated control channel (DCCH).

The UE Capability Information message may include at least one IE (Information Element) in which the release version and numbering are indicated, as shown in reference numerals 601 to 604.

That is, the UE Capability Information message may be configured so that the added function for each published standard version can be easily identified.

7 is a diagram illustrating a method of setting an SRS start offset according to an embodiment.

NR is a technology that operates over a very wide broadband compared to LTE, and has several design principles different from LTE in order to support a flexible broadband operation method.

First, the capabilities of the bandwidth supported by the network and the terminal may be different.

Second, the downlink and uplink bandwidth capabilities supported by the UE may be different.

Third, the capabilities of the bandwidth supported by each terminal may be different, and accordingly, terminals supporting different bandwidths may coexist within one network frequency band.

Fourth, in order to reduce the power consumption of the terminal, the bandwidth allocated to the terminal may be differently set according to the traffic load state of the terminal.

In order to satisfy the above design principle, the NR standard newly introduced the BWP (Band-Width Part) operation method in addition to the existing LTE carrier aggregation method.

The BWP operation method has the following characteristics.

Bandwidth-related capabilities supported by each terminal are different, and a carrier bandwidth from a network standpoint and a carrier bandwidth from a terminal standpoint may be different. To support this operation, carriers for each terminal may be configured differently, and one or several BWPs may be configured in each carrier.

In the phase 1 NR standard, which is the initial version of NR, it is assumed that only one BWP can be activated at one time in one carrier from the viewpoint of the terminal.

In order to reduce the power consumption of the terminal, the frequency bandwidth of the BWP can be dynamically changed, and the terminal can receive one or more BWPs and dynamically activate one of them.

A terminal operation may be performed within a BWP activated in one component carrier (CC).

The BWP can be largely divided into an uplink BWP and a downlink BWP, and each can be configured with a maximum of 4 carrier bandwidth parts.

The UE can receive a Physical Downlink Shared Channel (PDSCH), a Physical Downlink Control Channel (PDCCH), a CSI-RS, and a Tracking Reference Signal (TRS) only in the activated downlink BWP.

In addition, the UE may transmit a Physical Uplink Shared Channel (PUSCH) or a Physical Uplink Control Channel (PUCCH) only in an activated uplink BWP.

For example, within the activated BWP, the terminal monitors the control channel, CSI feedback. An operation such as sounding reference signal (SRS) transmission may be performed.

The SRS is a reference signal periodically or aperiodically transmitted by the terminal to the base station. In the network, the uplink radio channel state of the corresponding frequency band may be estimated based on the SRS received from the terminal.

One BWP may consist of a series of consecutive Physical Resource Blocks (PRBs).

In detail, FIG. 7 shows a method of setting an SRS start offset supported by the 3GPP standard prior to March 2019.

Referring to FIG. 7, Point A means a 5G radio resource-that is, a starting point of resource block grids--a common reference point -, and Point A may have the same starting point as a CC, which is a carrier bandwidth.

BWPstart means an offset from the start point of Point A or CC to the start point of BWP.

Nshift means the offset from the starting point of Point A to the starting point of the SRS in the BWP. Here, Nshift may have a value between 0 and 268.

According to the above definition, Nshift will always be greater than or equal to BWPstart.

8 is a diagram for describing a method of setting an SRS start offset according to another embodiment.

In detail, FIG. 8 shows a method of setting the SRS start offset supported by the 3GPP standard after March, 2019.

RP-190773, a change request (CR) document approved by the 3GPP General Assembly in March 2019, is a revised version of the existing RP-190219 document, and deals with the contents of "SRS starting position change".

8 is a view for explaining the SRS start position proposed in the document RP-190773.

Referring to FIG. 8, Point A means a 5G radio resource-that is, a starting point of resource block grids--a common reference point -, and Point A may not have the same starting point as a carrier bandwidth CC.

In this case, BWPstart means an offset from the start point of Point A to the start point of BWP, and Nshift means an offset from the start point of CC to the start point of SRS in BWP.

Here, Nshift may have a value between 0 and 268.

According to the embodiment of FIG. 8, Nshift is always smaller than BWPstart.

The definition of the SRS start offset of FIG. 8 contradicts the definition of FIG. 7.

The method according to FIG. 8 is a good suggestion to compensate for exceptional situations that the existing 5G standard did not consider, but as in Korea, the upgrade of the base station and the terminal in the future from the standpoint of starting 5G commercial services with a version earlier than December 2018. In addition, it takes a lot of time for the operation, and if all 5G terminals sold nationwide and all 5G terminals are not implemented as suggested by RP-190773, errors may occur in some terminals.

In addition, when the network does not accurately identify which 5G terminal is implemented as suggested by RP-190773, there is a problem that the configuration as shown in FIG. 8 cannot be made to the terminal.

If the network is implemented as suggested by RP-190773 and the network cannot identify the version mounted on the 5G terminal, it may not be possible to accurately set the SRS starting point corresponding to various BWP locations, which means that the network is uplinked. There is a problem in that communication performance is deteriorated by not accurately estimating the state of a radio channel.

9 is a flowchart illustrating an SRS control method in an NSA system according to an embodiment.

Referring to FIG. 9, a 5G terminal 910 may generate an SRB by performing an LTE basic Attach procedure with an eNB 920 that is a 4G LTE base station (S901).

The 5G terminal 910 may receive a UE Capability Inquiry message through the configured SRB (S902).

The 5G terminal 910 may identify the standard version applied to the network based on the IE included in the UE Capability Inquiry message (S903).

As an example, the 5G terminal 910 may identify a standard applied to the network by identifying whether the uecapabilityenquiry-v1550 IE is included in the UE Capability Inquiry message.

The 5G terminal 910 may compare the identified standard version with the reference version (S904). Here, the reference version may mean a standard version to which the CR of RP-190773 is first applied. For example, the reference version may be V1550.

If the identified standard version is greater than or equal to the reference version, the 5G terminal 910 may generate a CA-ParameterNR-v1550 IE including the aperiodic-CSI-diffSCS field (S905).

Here, aperiodic-CSI-diffSCS is a field indicating whether the UE supports triggering of aperiodic CSI-RS.

The 5G terminal 910 may set the aperiodic-CSI-diffSCS field value to “supported” (S906).

The 5G terminal 910 may transmit a UE Capability Information message including the CA-ParameterNR-v1550 IE-for convenience of description below, a first UE Capability Information message, a business card"-to the eNB 920 (S907).

The eNB 920 may transmit the received first UE Capability Information message to the en-gNB 930, which is a 5G NR base station (S908).

When the standard version identified in step 904 is a standard version prior to the reference version, the 5G terminal 910 provides a UE Capability Information message without CA-ParameterNR-v1550 IE-for convenience of description below, the second UE It is a Capability Information message, it is possible to transmit a business card”- to the eNB 920 (S909).

The eNB 920 may transmit the received second UE Capability Information message to the en-gNB 930, which is a 5G NR base station (S910).

The en-gNB 930 may determine whether the identified terminal version is greater than or equal to the reference version based on the IE included in the UE Capability Information message (S911).

For example, the en-gNB 930 may identify the terminal version based on whether the CA-ParameterNR-v1550 IE is included in the UE Capability Information message.

As a result of the determination in step 911, if the identified terminal version is greater than or equal to the reference version, the en-gNB 930 is assigned to a unique identifier in the cell of the version-identified terminal-for example, a cell radio network temporary identifier (C-RNTI). A corresponding SRS start position setting mode may be determined as the first mode (S912). Here, the first mode may be a mode operating in the SRS start offset setting method according to FIG. 8 described above.

As a result of the determination in step 911, if the identified terminal version is greater than or equal to the reference version, the en-gNB 930 is assigned to a unique identifier in the cell of the version-identified terminal-for example, a cell radio network temporary identifier (C-RNTI). A corresponding SRS start position setting mode may be determined as the second mode (S913). Here, the second mode may be a mode operating in the SRS start offset setting method according to FIG. 7 described above.

Although the embodiment of FIG. 9 is described in terms of the NSA system, the 5G NR base station may perform the role of the 4G LTE base station in the SA system.

In the above, even though all the components constituting the embodiments of the present invention are described as being combined into one and operating, the present invention is not necessarily limited to these embodiments. That is, within the scope of the object of the present invention, all of the constituent elements may be selectively combined and operated in one or more. In addition, although all the components may be implemented as one independent hardware, a program module that performs some or all functions combined in one or a plurality of hardware by selectively combining some or all of the components. It may be implemented as a computer program having Codes and code segments constituting the computer program may be easily inferred by those skilled in the art of the present invention. Such a computer program is stored in a computer-readable storage medium, and is read and executed by a computer, thereby implementing an embodiment of the present invention. The storage medium of the computer program may include a magnetic recording medium, an optical recording medium, and the like.

In addition, the terms such as "include", "consist of" or "have" described above mean that the corresponding component may be included unless otherwise stated, excluding other components. It should not be construed as being able to further include other components. All terms, including technical or scientific terms, unless otherwise defined, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms generally used, such as terms defined in the dictionary, should be interpreted as being consistent with the meaning in the context of the related technology, and are not interpreted as ideal or excessively formal meanings unless explicitly defined in the present invention.

In addition, in describing the constituent elements of the present invention, terms such as first, second, A, B, (a) and (b) may be used. These terms are for distinguishing the constituent element from other constituent elements, and the nature, order, or order of the constituent element is not limited by the term. When a component is described as being "connected", "defective" or "connected" to another component, that component may be directly connected or connected to that other component, but another component between each component It should be understood that an element may be “connected”, “defective” or “connected”.

The above-described methods may be implemented as computer-readable codes on a computer-readable recording medium. Computer-readable recording media include all types of recording media in which data that can be decoded by a computer system are stored. For example, there may be read only memory (ROM), random access memory (RAM), magnetic tape, magnetic disk, flash memory, optical data storage device, and the like. In addition, the computer-readable recording medium may be distributed to a computer system connected through a computer communication network, stored as a code that can be read in a distributed manner, and downloaded to the corresponding device to be executed.

In addition, although the above has been described with reference to a preferred embodiment of the present invention, those of ordinary skill in the relevant technical field can use the present invention within the scope not departing from the spirit and scope of the present invention described in the following claims. It will be appreciated that various modifications and changes can be made.

Claims (21)

In the SRS (Sounding Reference Signal) control method in a terminal accessible to a non-stand alone (NSA) 5G network,
Configuring a signaling radio bearer (SRB) by performing an initial access procedure with a first base station;
Receiving a terminal capability query message from the first base station through the SRB;
Identifying a standard version applied to a network based on an information element (IE) included in the terminal capability query message; And
If the identified standard version is greater than or equal to the reference version, transmitting a terminal capability information message including CA-ParameterNR-v1550 IE to the first base station
SRS control method in the terminal comprising a. The method of claim 1,
When the uecapabilityenquiry-v1550 IE is included in the terminal capability query message, the SRS control method at the terminal determines that the standard version applied to the network is greater than or equal to the reference version. The method of claim 1,
The CA-ParameterNR-v1550 IE includes an aperiodic-CSI-diffSCS field indicating whether the terminal supports triggering of aperiodic Channel State Indicator-Reference Signal (CSI-RS). The method of claim 3,
The aperiodic-CSI-diffSCS field value is set to "Supported" SRS control method in the terminal. The method of claim 1,
The terminal is a 5G terminal, the first base station is a 4G LTE (Long Term Evolution) base station SRS control method in the terminal. The method of claim 5,
The terminal capability information message is transmitted to a second base station through the first base station, and the second base station is a 5G NR (New Radio) base station. The method of claim 6,
The second base station identifies the standard version applied to the terminal based on the IE included in the terminal capability information message, and determines the SRS start position change mode by comparing the standard version applied to the terminal with the reference version. SRS control method in the terminal, characterized in that. The method of claim 7,
If the standard version applied to the terminal is equal to or greater than the reference version, the SRS start position change mode is determined as the first mode. The method of claim 8,
In the first mode, the SRS in the terminal, characterized in that _{N shift, which} is the start offset of the SRS in the carrier component (CC _{), is smaller than the start offset BWP start} of the Band-Width Part (BWP) through which the SRS is transmitted. Control method. The method of claim 9,
When the standard version applied to the terminal is smaller than the reference version, the SRS start position change mode is determined as a second mode. The method of claim 10,
The second mode SRS control method in the terminal, characterized in that _{the N shift} is greater than or equal to the BWP _start. The method of claim 11,
_{The reference point of the BWP start} corresponding to the first to second modes is Point A, which is a starting point of 5G radio resources,
_{The reference point of the N shift} corresponding to the first mode is the starting point of the CC,
The SRS control method in the terminal, characterized in that the reference point of _{the N shift} corresponding to the second mode is the Point A. In the SRS (Sounding Reference Signal) control method in a system including a 4G LTE (Long Term Evolution) base station and a 5G NR (New Radio) base station,
Configuring a signaling radio bearer (SRB) by the 4G LTE base station performing an initial access procedure with a 5G terminal;
Transmitting, by the 4G LTE base station, a terminal capability query message to the 5G terminal through the SRB;
Receiving, by the 4G LTE base station, a terminal capability information message from the 5G terminal and transmitting it to the 5G NR base station; And
The 5G NR base station identifies the standard version applied to the terminal based on the information element (IE) included in the terminal capability information message, compares the standard version applied to the terminal with the reference version, and SRS start position change mode Steps to determine
SRS control method in a system comprising a. The method of claim 13,
The 5G NR base station determines the SRS start position change mode as the first mode when the CA-ParameterNR-v1550 IE is included in the terminal capability information message. The method of claim 14,
When the uecapabilityenquiry-v1550 IE is included in the terminal capability query message, the 5G terminal determines that the standard version applied to the system is equal to or greater than the reference version, and the terminal capability including the CA-ParameterNR-v1550 IE SRS control method in a system that transmits an information message. The method of claim 15,
The CA-ParameterNR-v1550 IE includes an aperiodic-CSI-diffSCS field indicating whether the terminal supports triggering of aperiodic Channel State Indicator-Reference Signal (CSI-RS),
SRS control method in a system in which the aperiodic-CSI-diffSCS field value is set to “Supported”. The method of claim 16,
When the 5G NR base station does not include the CA-ParameterNR-v1550 IE in the terminal capability information message, the SRS control method in a system for determining the SRS start position change mode as a second mode. The method of claim 17,
In the first mode, the SRS in the system, characterized in that _{N shift, which} is the start offset of the SRS in the carrier component (CC _{), is smaller than the start offset BWP start} of the Band-Width Part (BWP) through which the SRS is transmitted. Control method. The method of claim 18,
In the second mode, the N _shift is greater than or equal to the BWP _start. The method of claim 19,
_{The reference point of the BWP start} corresponding to the first to second modes is Point A, which is a starting point of 5G radio resources,
_{The reference point of the N shift} corresponding to the first mode is the starting point of the CC,
The SRS control method in a system, characterized in that the reference point of _{the N shift} corresponding to the second mode is the Point A. A recording medium on which a program for executing the method according to any one of claims 1 to 20 is recorded.

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