KR102420813B1 - Method and apparatus for transmitting and receiving data in a mobile communication system - Google Patents

Abstract

The present disclosure relates to a communication technique that converges a 5G communication system for supporting a higher data rate after a 4G system with IoT technology, and a system thereof. The present disclosure provides intelligent services (eg, smart home, smart building, smart city, smart car or connected car, healthcare, digital education, retail business, security and safety related services, etc.) based on 5G communication technology and IoT-related technology. ) can be applied to The present invention discloses a technique for a cell reselection operation in a mobile communication system.
The present invention provides a method of a terminal in a wireless communication system, the method comprising: receiving scheduling information for a first band from a base station; switching a bandwidth to a first band according to the scheduling information; starting a timer for the first band; and switching to the second band when the timer expires.

Description

Method and apparatus for transmitting and receiving data in a mobile communication system

The present disclosure relates to a mobile communication system, and more particularly, to a cell reselection method of a terminal.

In addition, the present disclosure relates to a cell measurement and mobility management operation using signals transmitted through beamforming in a beamforming-based system.

In addition, the present disclosure relates to a method of transmitting a reference signal for a terminal in a radio resource control (RRC) connection state.

In addition, the present disclosure relates to a method of switching a bandwidth of a terminal in a mobile communication system.

Efforts are being made to develop an improved 5G communication system or pre-5G communication system in order to meet the increasing demand for wireless data traffic after commercialization of the 4G communication system. For this reason, the 5G communication system or the pre-5G communication system is called a system after the 4G network (Beyond 4G Network) communication system or the LTE system after (Post LTE). In order to achieve a high data rate, the 5G communication system is being considered for implementation in a very high frequency (mmWave) band (eg, such as a 60 gigabyte (60 GHz) band). In order to alleviate the path loss of radio waves and increase the propagation distance of radio waves in the very high frequency band, in the 5G communication system, beamforming, massive MIMO, and Full Dimensional MIMO (FD-MIMO) are used. ), array antenna, analog beam-forming, and large scale antenna technologies are being discussed. In addition, for network improvement of the system, in the 5G communication system, an evolved small cell, an advanced small cell, a cloud radio access network (cloud radio access network: cloud RAN), an ultra-dense network (ultra-dense network) , Device to Device communication (D2D), wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), and interference cancellation Technology development is underway. In addition, in the 5G system, the advanced coding modulation (ACM) methods FQAM (Hybrid FSK and QAM Modulation) and SWSC (Sliding Window Superposition Coding), and advanced access technologies FBMC (Filter Bank Multi Carrier), NOMA (non orthogonal multiple access), and sparse code multiple access (SCMA) are being developed.

On the other hand, the Internet is evolving from a human-centered connection network where humans create and consume information to an Internet of Things (IoT) network that exchanges and processes information between distributed components such as objects. Internet of Everything (IoE) technology, which combines big data processing technology through connection with cloud servers, etc. with IoT technology, is also emerging. In order to implement IoT, technology elements such as sensing technology, wired and wireless communication and network infrastructure, service interface technology, and security technology are required. , M2M), and MTC (Machine Type Communication) are being studied. In the IoT environment, an intelligent IT (Internet Technology) service that collects and analyzes data generated from connected objects and creates new values in human life can 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, advanced medical service, etc. can be applied to

Accordingly, various attempts are being made to apply the 5G communication system to the IoT network. For example, in technologies such as sensor network, machine to machine (M2M), and MTC (Machine Type Communication), 5G communication technology is implemented by techniques such as beam forming, MIMO, and array antenna. there will be The application of a cloud radio access network (cloud RAN) as the big data processing technology described above is an example of the convergence of 5G technology and IoT technology.

The above information is provided as background information to aid in understanding the subject matter of this disclosure. No determination has been made and no claim has been made as to whether any of the above may be applied as prior art with respect to the present disclosure.

The present invention is made to solve at least the above problems and/or disadvantages and to provide at least the advantages described below.

According to the present disclosure, at least the aforementioned problems and/or disadvantages are solved and at least the advantages described below are provided. An object of the present disclosure is to provide a method for the UE to preferentially reselect a specific cell to enable fast data transmission/reception of the UE and to prevent an increase in signaling overhead that occurs during a data transmission/reception preparation procedure.

Another object of the present disclosure is to provide a system, method and apparatus for performing cell measurement and mobility management operations using signals transmitted through beamforming in a beamforming-based system including one or more base stations and one or more terminals. will be.

In addition, another object of the present disclosure is to provide a method and apparatus for transmitting a reference signal for a terminal in a radio resource control (RRC) connection state.

Another object of the present disclosure is to provide a procedure for receiving a base station signal in a limited band in consideration of the power consumption of the terminal on a single carrier, and to provide a method for the base station and the terminal to dynamically and flexibly utilize the entire system bandwidth. will provide In addition, the present disclosure is to provide a method and procedure for a terminal to save power in such a flexible bandwidth (flexible BW) system.

According to an aspect of the present disclosure, a method of a terminal in a wireless communication system is provided. The method includes: receiving first scheduling information for a first frequency band from a base station; switching a bandwidth to a first frequency band according to the first scheduling information; starting a timer for the first frequency band; and switching to the second frequency band when the timer expires.

Further, according to an aspect of the present disclosure, a method of a base station in a wireless communication system is provided. The method includes transmitting first scheduling information for a first frequency band to the terminal; switching a bandwidth to a first frequency band according to the first scheduling information; starting a timer for the first frequency band; and switching to the second frequency band when the timer expires.

In addition, according to an aspect of the present disclosure, a terminal in a wireless communication system is provided. The terminal includes a transceiver; and receiving first scheduling information for a first frequency band from a base station, switching a bandwidth to a first frequency band according to the first scheduling information, starting a timer for the first frequency band, and the timer expires It is characterized in that it comprises a control unit for switching to the second frequency band when it is.

In addition, a base station in a wireless communication system is provided according to an aspect of the present disclosure. The base station includes a transceiver; and transmitting first scheduling information for a first frequency band to the terminal, switching a bandwidth to a first frequency band according to the first scheduling information, starting a timer for the first frequency band, and the timer expires It is characterized in that it comprises a control unit for switching to the second frequency band when it is.

According to an embodiment of the present disclosure, the terminal preferentially reselects a specific cell capable of fast data transmission and reception, thereby enabling fast data transmission and reception of the terminal and preventing an increase in signaling overhead that occurs during a data transmission/reception preparation procedure. .

In addition, according to another embodiment of the present disclosure, each base station can transmit two or more types of reference signals generated by different signal generation rules using two or more types of beams having different beam areas, coverages, transmission periods, etc. have.

In addition, according to another embodiment of the present disclosure, the base station can determine a beam to be used for data transmission by transmitting a reference signal for the terminal in the RRC connection state, and use the beam for data transmission and reception.

Also, according to another embodiment of the present disclosure, the base station may control multiple terminals using bands of various sizes to evenly use resources in the operating band of the system. In addition, the base station allows the UE to perform scheduling, Modulation and Coding Scheme (MCS), Channel State Indication (CSI) reporting, and measurement within the configured partial band, but reduces scheduling and handover performance for the entire band. can be minimized. In addition, when a connection problem occurs within the partial band configured by the terminal, it can be recovered within a short delay.

Other aspects, advantages, and salient features of the present disclosure will become apparent to those skilled in the art from the following detailed description taken in conjunction with the accompanying drawings, which discloses various embodiments of the present disclosure.

These and other aspects, features and advantages of any embodiment of the present disclosure will become more apparent from the following description taken in conjunction with the accompanying drawings.
1 is a diagram illustrating a situation in which a terminal moves in a radio access network (RAN) area after transitioning from a connected mode to an inactive mode according to an embodiment of the present disclosure.
FIG. 2 is a diagram illustrating an operation in which an inactive mode terminal receives downlink (DL) data from a base station having a valid cell radio network temporary identifier (C-RNTI) according to an embodiment of the present disclosure.
3 is a diagram illustrating an operation in which an inactive mode terminal receives DL data from all base stations in a RAN area through an area radio network temporary identifier (A-RNTI) according to an embodiment of the present disclosure.
4 is a base station in which an inactive mode terminal receives a paging signal through A-RNTI from all base stations in a RAN area, performs a 2-step random access channel (RACH), and then receives a RACH preamble according to an embodiment of the present disclosure; It is a diagram illustrating an operation of receiving DL data from the A-RNTI.
5 is a diagram illustrating an inactive mode terminal receiving a paging signal through A-RNTI from all base stations in a RAN area, performing 4-step RACH, and then receiving an A-RNTI from a base station that has received a RACH preamble according to an embodiment of the present disclosure. It is a diagram illustrating an operation of receiving DL data through the
6 is a diagram for explaining a difference between a base station having a valid C-RNTI and a base station not having a valid C-RNTI in cell reselection of an inactive mode terminal according to an embodiment of the present disclosure.
7 is a diagram for explaining a cell reselection operation in a situation in which an inactive mode terminal moves from a base station having a valid C-RNTI to a base station not having a valid C-RNTI according to an embodiment of the present disclosure.
8 is a diagram for explaining a cell reselection operation in a situation in which an inactive mode terminal moves from a base station not having a valid C-RNTI to a base station having a valid C-RNTI according to an embodiment of the present disclosure.
9 is a diagram for explaining a cell reselection operation in a situation in which an inactive mode terminal moves from a base station not having a valid C-RNTI to a base station not having a valid C-RNTI according to an embodiment of the present disclosure.
10 is a diagram for explaining a cell reselection operation in a situation in which an inactive mode terminal moves from a base station having a valid C-RNTI to a base station having a valid C-RNTI according to an embodiment of the present disclosure.
11 is a diagram illustrating that different types of reference signals having the same period are transmitted through different frequency bands according to an embodiment of the present disclosure.
12 is a diagram illustrating that different types of reference signals having the same period are transmitted through the same frequency band according to an embodiment of the present disclosure.
13 is a diagram illustrating that different types of reference signals having different periods are transmitted through the same frequency band according to an embodiment of the present disclosure.
14 is a diagram illustrating a method in which a terminal calculates a measurement value of a cell in which corresponding signals are transmitted using different reference signals according to an embodiment of the present disclosure.
15 is a diagram illustrating a method of classifying measured signals by reference signals of the same type and calculating a representative value of one cell using a measured value according to an embodiment of the present disclosure.
16 is a diagram illustrating a method of calculating a cell representative value using all reference signals measured according to an embodiment of the present disclosure.
17 is a diagram illustrating a method of calculating a cell representative value according to an embodiment of the present disclosure.
18 is a diagram illustrating an example of a signal that a base station transmits to a terminal and that can be used to calculate a cell measurement value according to an embodiment of the present disclosure.
19 is a diagram illustrating an example of a signal that a base station transmits to a terminal and that can be used to calculate a cell measurement value according to an embodiment of the present disclosure.
20 is a diagram illustrating an example in which weights are included in signals transmitted from a base station to a terminal and transmitted according to an embodiment of the present disclosure.
21 is a diagram for explaining a method for a UE to calculate a cell representative value for each RS (reference signal) through a separate procedure from different RSs according to an embodiment of the present disclosure.
22 is a diagram illustrating a method of controlling a change in mobility using different types of reference signals according to an embodiment of the present disclosure.
23 is a diagram illustrating a method of determining a representative value for each reference signal with respect to different types of reference signals and deriving a cell representative value by multiplying the representative value by a weight according to an embodiment of the present disclosure.
24 is a diagram illustrating a method of deriving a cell representative value by multiplying each beam measurement signal by the same weight for the same type of reference signal according to an embodiment of the present disclosure.
25 is a diagram illustrating a method of selecting a specific number of beam measurement signals with respect to different types of reference signals and deriving a cell representative value by multiplying them by different weights according to an embodiment of the present disclosure.
26 is a diagram illustrating another method of selecting a specific number of beam measurement signals with respect to different types of reference signals and deriving a cell representative value by multiplying different weights according to an embodiment of the present disclosure.
27 is a diagram illustrating another method of selecting a different number of beam measurement signals for different types of reference signals and deriving a cell representative value by multiplying different weights according to an embodiment of the present disclosure.
28 is a diagram illustrating a method of deriving a cell representative value by multiplying all beam measurement signals by different weights with respect to different types of reference signals according to an embodiment of the present disclosure.
29 is a diagram illustrating a method of controlling a change in mobility using different types of reference signals according to an embodiment of the present disclosure.
30 is a diagram illustrating a terminal according to an embodiment of the present disclosure.
31 is a diagram illustrating a base station according to an embodiment of the present disclosure.
32 is a flowchart illustrating an initial access operation according to an embodiment of the present disclosure.
33 is a flowchart illustrating a handover operation according to an embodiment of the present disclosure.
34 is a flowchart illustrating an operation according to an embodiment of the present disclosure.
35 is a flowchart illustrating a method of determining a beam to be used for data transmission/reception in a handover process according to an embodiment of the present disclosure.
36 is a flowchart illustrating another method of determining a beam to be used for data transmission/reception in a handover process according to an embodiment of the present disclosure.
37 is a flowchart illustrating another method of determining a beam to be used for data transmission/reception in a handover process according to an embodiment of the present disclosure.
38 is a flowchart illustrating another method of determining a beam to be used for data transmission/reception in a handover process according to an embodiment of the present disclosure.
39 is a flowchart illustrating another method of determining a beam to be used for data transmission/reception in a handover process according to an embodiment of the present disclosure.
40 is a flowchart illustrating another method of determining a beam to be used for data transmission/reception in a handover process according to an embodiment of the present disclosure.
41 is a flowchart illustrating another method of determining a beam to be used for data transmission/reception in a handover process according to an embodiment of the present disclosure.
42 is a flowchart illustrating a random access operation according to an embodiment of the present disclosure.
43 is a flowchart illustrating a method of determining a beam to be used for data transmission/reception in a random access process according to an embodiment of the present disclosure.
44 is a flowchart illustrating another method of determining a beam to be used for data transmission/reception in a random access process according to an embodiment of the present disclosure.
45 is a flowchart illustrating another method of determining a beam to be used for data transmission/reception in a random access process according to an embodiment of the present disclosure.
46 is a flowchart illustrating another method of determining a beam to be used for data transmission/reception in a random access process according to an embodiment of the present disclosure.
47 is a flowchart illustrating another method of determining a beam to be used for data transmission/reception in a random access process according to an embodiment of the present disclosure.
48 is a diagram illustrating an LTE Scalable BW system.
49 is a diagram illustrating features of a 5G NR Flexible BW system according to an embodiment of the present disclosure.
50 is a diagram illustrating various band division schemes in a 5G NR Flexible BW system according to an embodiment of the present disclosure.
51 is a diagram illustrating a self/cross-band scheduling operation according to an embodiment of the present disclosure.
52 is a diagram illustrating Example-I of BW expansion and reduction operation by a physical layer control signal according to an embodiment of the present disclosure.
53 is a diagram illustrating Example-II of a BW expansion and reduction operation by a physical layer control signal according to an embodiment of the present disclosure.
54 is a diagram illustrating Example-III of BW expansion and reduction operation by a physical layer control signal according to an embodiment of the present disclosure.
55 is a diagram illustrating an example-I of BW expansion and reduction operations using a physical layer and an RRC control signal according to an embodiment of the present disclosure.
56 is a diagram illustrating Example-II of BW expansion and reduction operations using a physical layer and an RRC control signal according to an embodiment of the present disclosure.
57 is a diagram illustrating Example-III of BW expansion and reduction operations using a physical layer and an RRC control signal according to an embodiment of the present disclosure.
58 is a diagram illustrating an example-IV of BW expansion and reduction operations using a physical layer and an RRC control signal according to an embodiment of the present disclosure.
59 is a diagram illustrating Example-I of C-DRX operation for adaptive BW according to an embodiment of the present disclosure.
60 is a diagram illustrating Example-II of C-DRX operation for adaptive BW according to an embodiment of the present disclosure.
61 is a diagram illustrating an example of DRX configuration for each wideband and narrowband according to an embodiment of the present disclosure.
62 is a diagram illustrating Example-I according to the DRX configuration and priority rule for each wideband and narrowband according to an embodiment of the present disclosure.
63 is a diagram illustrating Example-II according to the DRX configuration and priority rule for each wideband and narrowband according to an embodiment of the present disclosure.
64 is a flowchart for an example of a C-DRX procedure in consideration of BW switching according to an embodiment of the present disclosure.
65 is a diagram illustrating an operation according to a definition of a DRX variable when a normal TTI is switched to a short TTI according to an embodiment of the present disclosure.
FIG. 66 is a diagram illustrating an example in which a TTI value is differently determined according to a situation according to a control channel monitoring periodicity and a transmission duration according to an embodiment of the present disclosure.
67 is a diagram for explaining an operation of switching a band based on a timer according to an embodiment of the present disclosure.
68 is a diagram illustrating a switching operation between bands based on a timer according to an embodiment of the present disclosure.
69 is another diagram illustrating a switching operation between bands based on a timer according to an embodiment of the present disclosure.
70 is another diagram illustrating an inter-band switching operation based on a timer according to an embodiment of the present disclosure.
71 is another diagram illustrating an inter-band switching operation based on a timer according to an embodiment of the present disclosure.
72 is a diagram illustrating a configuration of a terminal device according to an embodiment of the present disclosure.
73 is a diagram illustrating a configuration of a base station according to an embodiment of the present disclosure.
It should be noted that throughout the drawings, the same reference numbers are used to refer to the same or similar elements, features, and structures.

The following description with reference to the accompanying drawings is provided to provide a comprehensive understanding of various embodiments of the disclosure as defined by the claims and their equivalents. It contains various specific details to aid its understanding, but these should be considered as examples only. Accordingly, those skilled in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and configurations may be omitted for clarity and brevity.

The terms and words used in the following detailed description and claims are not limited to the meaning of the bibliography, but are used solely by the inventors to enable a clear and consistent understanding of the present disclosure. Accordingly, it will be apparent to those skilled in the art that the following description of various embodiments of the present disclosure is for illustrative purposes only and is not intended to limit the disclosure as defined by the appended claims and their equivalents.

It is to be understood that the singular forms "a", "an" and "the" include plural objects unless the context clearly dictates otherwise. Thus, for example, reference to “a component surface” includes reference to one or more such surfaces.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the art to which the present invention pertains. It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

<First embodiment>

In New Radio (NR), which is currently under discussion in 3GPP, introduction of an inactive mode has been confirmed in addition to the connected mode and idle mode defined in LTE. Inactive mode features and requirements are as follows.

- Signaling and resource use in a radio access network (RAN) and a core network (CN) should be minimized.

- The time required to transmit data in the inactive state should be minimized. Here, data transmission may be performed while the terminal maintains an inactive state or may be performed in a connected state.

- In addition to paging by CN of existing LTE, paging by RAN should be supported.

- A RAN-based notification area (hereinafter, RAN area) is defined, and the UE moves without location update in the RAN area. And base stations in the RAN area maintain an access stratum (AS) context of the terminal.

According to the above requirements, the inactive mode terminal must be able to perform an operation for fast data transmission and reception. One of them is cell reselection. Basically, as in the above requirements, the inactive mode terminal moves without location update within the RAN area. However, when the inactive mode terminal performs cell reselection through the same operation as the idle mode terminal in the existing LTE, it may be inappropriate in terms of fast data transmission and reception.

1 is a diagram illustrating a situation in which a terminal moves in a RAN area after transitioning to an inactive mode according to an embodiment of the present disclosure.

1 shows an environment considered in the present disclosure, in which a plurality of base stations are gathered to form a RAN notification area, and in the RAN notification area, a base station having a C-RNTI effective for an inactive mode terminal and a base station not and shows a situation in which the inactive mode terminal is freely moving within the RAN notification area.

Referring to FIG. 1, FIG. 1 shows a situation in which a terminal connected to a base station 110 having a C-RNTI is freely moving within a RAN area after transitioning from a connected mode to an inactive mode.

In FIG. 1 , the base station 110 is a base station from which the terminal last received a service, and thus the C-RNTI (Cell Radio Network Temporary Identifier) used by the terminal is also maintained according to the definition of the inactive state maintaining the AS context of the terminal. Therefore, if the inactive mode terminal transmits/receives data to and from the base station 110 , there is no need to reconfigure the C-RNTI.

Next, the base station 120 that does not have the C-RNTI of FIG. 1 corresponds to a base station that belongs to the RAN area of the terminal but does not have the C-RNTI of the inactive mode terminal that was last serviced by the base station 110 . Therefore, when the inactive mode terminal communicates with the base station 120 instead of the base station 110 having the terminal's C-RNTI while moving within the RAN area, the corresponding base station needs a procedure for allocating the C-RNTI to the terminal. . This may be a factor that increases the delay when the inactive mode terminal performs fast data transmission and reception.

Currently, in 3GPP, a discussion is underway to introduce a separate RNTI (radio network temporary identifier) for data transmission and reception of an inactive mode terminal. In the present disclosure, this is called A-RNTI (Area RNTI). The A-RNTI is an identifier designed to be uniquely assigned to all terminals in the RAN area. Since the RAN area includes a plurality of cells, the A-RNTI has a higher overhead than the C-RNTI designed to be uniquely allocated to terminals within the cell.

2 to 5 below show an operation in which an inactive mode terminal receives DL data from a base station in a RAN area according to an embodiment of the present disclosure.

FIG. 2 is a diagram illustrating an operation in which an inactive mode terminal receives DL data from a base station maintaining its C-RNTI in a RAN area according to an embodiment of the present disclosure.

Referring to FIG. 2 , since the base station has the C-RNTI, the base station may transmit data using the C-RNTI in step S210.

3 to 5 are diagrams illustrating an operation in which an inactive mode terminal receives DL data from a base station that does not maintain its own C-RNTI in a RAN area according to an embodiment of the present disclosure.

More specifically, FIG. 3 shows an operation (S310) in which all base stations belonging to the RAN area transmit DL data to the inactive mode terminal by using the A-RNTI. In most cases, since an actual terminal is adjacent to one base station, it is inefficient use of resources for all base stations in the RAN area to transmit DL data using the unique A-RNTI as described above.

4 and 5 show that the base station adjacent to the terminal transmits DL data after the inactive mode terminal performs the operation of checking the base station adjacent to the terminal by performing step 2 and step 4 RACH, respectively, according to an embodiment of the present disclosure. It is a drawing showing the operation.

First, all base stations belonging to the RAN area perform paging by using the A-RNTI of the terminal (S410, S510). Next, the terminal responding to the paging performs step 2 or step 4 RACH and informs the base station that it is a terminal corresponding to the A-RNTI included in the paging signal in RACH message 1 (S420) or RACH message 3 (S520). Upon receiving this, the base station understands that the inactive mode terminal is in its vicinity and transmits DL data. This operation causes overhead because all base stations in the RAN area transmit a paging signal. In addition, there is an overhead in the procedure for the UE to perform the 2nd or 4th stage RACH operation.

Referring to FIGS. 2 to 5 , it can be confirmed that data transmission and reception of the inactive mode terminal has the least delay and requires the least signaling between the terminal and the base station when the base station has a valid C-RNTI. Therefore, it is advantageous for the inactive mode terminal to stay in the base station having a valid C-RNTI for as long as possible. This aspect should be reflected in the cell reselection operation of the inactive mode terminal. The present disclosure proposes a cell selection operation for allowing the terminal to stay in the base station having a valid C-RNTI for as long as possible for the inactive mode terminal.

First, the cell reselection operation of the UE in LTE will be described. In LTE, cell reselection of an idle mode terminal means an operation of selecting a cell that receives a paging signal while the terminal acquires system information while camping and maintains synchronization. In order to understand the cell reselection operation, it is necessary to understand the cell selection operation. Cell selection includes the operation of checking whether Srxlev > 0 after the UE measures and induces the Srxlev below (details are the same as in the LTE standard, so in this document, to be omitted). Here, Srxlev is composed of Qrxlevmeas, Qrxlevmin, Qrxlevminoffset, Pcompensation, etc. Qrxlevmeas corresponds to the RSRP (reference signal received power) value measured by the UE, and the remaining Qrxlevmin, Qrxlevminoffset, Pcompensation, etc. It is a parameter that informs

[Table 1]

Based on the concept of a suitable cell, that is, a cell in which Srxlev > 0, described above, LTE performs cell reselection through the following operation. First, the terminal derives Rs and Rn after measuring the signal strength of the cell currently camping and surrounding cells. Here, Qmeas,s and Qmeas,n refer to the signal strength (RSRP) for the cell currently camping and surrounding cells. In addition, Qhyst,s and Qoffset,n are parameters provided by the base station to the terminal in order to prevent frequent cell reselection. After measuring the signal strength for the cell in this way, the terminal selects the cell with the highest Rs or Rn among the cells with Srxlev > 0 and performs camping in the corresponding cell. Here, if the cell currently camping and the newly selected cell are different, the terminal is said to have performed cell reselection.

[Table 2]

So far, the cell reselection process of idle mode UEs in LTE has been described. In addition, in the inactive mode, which is expected to be newly introduced in NR, it is advantageous in terms of fast data transmission and reception of the inactive mode terminal for the terminal to stay in the cell having a valid C-RNTI for as long as possible. Considering this point, we propose a cell reselection operation suitable for fast data transmission and reception of a terminal in inactive mode. For reference, in this document, a base station is used in parallel with the term cell. Therefore, a cell having a C-RNTI effective to the inactive mode terminal can be considered to have the same meaning as a base station, gNB, or eNB having a C-RNTI effective to the inactive mode terminal.

In the present disclosure, during cell reselection, an additional offset is applied to a base station that has a valid C-RNTI for an inactive mode terminal, regardless of whether a specific cell is a serving cell or a neighbor cell, so that the inactive mode terminal provides a valid C-RNTI to itself. We propose a method that allows you to stay in the base station you have for as long as possible.

6 is a diagram illustrating a cell reselection method of an inactive mode terminal according to an embodiment of the present disclosure.

Referring to FIG. 6 , for the base station 610 having a C-RNTI effective for the inactive mode terminal, the inactive mode terminal adds QC-RNTI, which is an additional offset during cell reselection, to the cell ranking and reflects it in the cell ranking, and the effective C for the inactive mode terminal - Shows a method of performing cell ranking without an additional offset for the base station 620 that does not have an RNTI.

The basic cell reselection operation is the same as described above, and as shown in FIG. 6 , in the case of a base station having a valid C-RNTI of an inactive mode terminal, the terminal applies an additional offset (specified as Q _C-RNTI in this document) can do. According to the present disclosure, for a base station that does not have a C-RNTI valid for the inactive mode terminal, the terminal does not apply an additional offset Q _C-RNTI . The cell reselection formula according to the present disclosure is as follows.

[Table 3]

Or it could be:

[Table 4]

The inactive mode terminal performs a cell reselection operation according to the above formula in three situations as shown in FIGS. 7 to 9 below.

7 is a diagram illustrating a cell reselection operation in a situation in which an inactive mode terminal moves from a base station having a valid C-RNTI to a base station not having a valid C-RNTI according to an embodiment of the present disclosure.

Referring to Figure 7, it is assumed that the current terminal is camping in a base station having a valid C-RNTI. According to the present disclosure, it is advantageous in terms of fast data transmission and reception for a terminal to stay as long as possible in a cell currently camping, that is, a base station having a valid C-RNTI. Therefore, when deriving Rs for the cell currently camping in the ranking process for cell reselection, the terminal adds Q _C-RNTI,s to Q _meas,s and Q _hyst,s .

However, since the base station 720 to which the terminal is moving does not have a valid C-RNTI, the terminal does not apply an additional offset other than Q _meas,n and Q _offset,n . In this example, the inactive mode terminal derives Rs and Rn in this way and compares them with each other to perform final cell reselection.

[Table 5]

8 is a diagram illustrating a cell reselection operation in a situation in which an inactive mode terminal moves from a base station not having a valid C-RNTI to a base station having a valid C-RNTI according to an embodiment of the present disclosure.

Referring to FIG. 8, it is assumed that the current terminal is camping in a base station that does not have a valid C-RNTI. According to the present disclosure, it is advantageous in terms of fast data transmission and reception for a terminal to stay as long as possible in a neighbor cell, that is, a base station having a valid C-RNTI, rather than staying in a cell currently camping, that is, a base station that does not have a valid C-RNTI. . Therefore, in the ranking process for cell reselection, when deriving Rs for the currently camping cell, the terminal does not apply any additional offset other than Q _meas,s and Q _hyst,s .

On the other hand, since the base station 810 to which the terminal is moving has a C-RNTI valid for the terminal, the terminal adds Q _C-RNTI,n to Q _meas,n and Q _offset,s,n when deriving Rn for a neighbor cell. do. In this example, the inactive mode terminal derives Rs and Rn in this way and compares them to perform final cell reselection.

[Table 6]

9 is a diagram illustrating a cell reselection operation in a situation in which an inactive mode terminal moves from a base station not having a valid C-RNTI to a base station not having a valid C-RNTI according to an embodiment of the present disclosure.

Referring to FIG. 9 , it is assumed that the current terminal is camping in the base station 920 that does not have a valid C-RNTI. The present disclosure mainly produces an effect different from the existing method in cell reselection between a base station having a valid C-RNTI and a base station not having a valid C-RNTI. Therefore, the situation of FIG. 9 is similar to the conventional cell reselection operation. That is, the terminal does not apply additional offsets other than Q _meas,s and Q _hyst,s when deriving Rs for the cells currently camping in the ranking process for cell reselection. In addition, the UE does not apply additional offsets other than Q _meas,n and Q _hyst,n when deriving Rn for the neighbor cell. In this example, the inactive mode terminal derives Rs and Rn in this way and compares them to perform final cell reselection.

[Table 7]

10 is a diagram illustrating a cell reselection operation in a situation in which an inactive mode terminal moves from a base station having a valid C-RNTI to a base station having a valid C-RNTI according to an embodiment of the present disclosure.

In an environment where cooperative transmission/reception is performed, a plurality of base stations may have C-RNTIs. In this situation, the terminal can apply an additional offset in addition to Q _meas,s and Q _hyst,s when deriving Rs for the cell currently camping in the ranking process for cell reselection. In addition, when deriving Rn for a neighbor cell, the UE may apply an additional offset in addition to Q _meas,n and Q _offset,s,n . In this example, the inactive mode terminal can perform final cell reselection by deriving Rs and Rn in this way and comparing them with each other.

[Table 8]

In the present disclosure, when the inactive mode terminal performs cell reselection, an additional offset is applied to the base station having a valid C-RNTI, so that the terminal can stay in the base station having a valid C-RNTI for as long as possible. In the present disclosure, the operation and gist of the present disclosure is limited to a base station having a valid C-RNTI, but this may be extended to any base station. Here, an arbitrary base station includes the following examples.

- Example 1: Macro cell

- Example 2: Home cell (HeNB)

- Example 3: A specific cell designated by the base station to the terminal through system information or RRC signaling

- Example 4: Cells using a specific frequency, for example, frequencies below or above 6 GHz

- Example 5: Cell installed and operated by a specific operator

Therefore, when the present disclosure is applied, the UE can preferentially perform cell reselection for the cell as in the example described above.

<Second embodiment>

Due to the advent of smart phones, users' smart phone usage is increasing exponentially, and the demand for battery life increase for continuous smart phone use of these users is increasing. This means that an efficient power saving technology is required, and for this, the terminal needs to operate in a power saving mode. Various techniques have been proposed and standardized for efficient terminal power saving, to enable the terminal to operate in a power saving mode more frequently, and to re-establish a connection with a network more quickly.

In order to achieve the high data rate considered in this patent, the 5G communication system is being considered for implementation in a very high frequency (mmWave) band (eg, 60 gigabytes (60 GHz) band). In order to mitigate the path loss of radio waves and increase the propagation distance of radio waves in the ultra-high frequency band, in the 5G communication system, beamforming, massive multiple-input multiple-output (MIMO), and all-dimensional multiple-input/output (Full Dimensional MIMO: FD-MIMO), array antenna (array antenna), analog beam-forming (analog beam-forming), and large-scale antenna (large scale antenna) technologies are being discussed.

In addition, for network improvement of the system, in the 5G communication system, an evolved small cell, an advanced small cell, a cloud radio access network (cloud radio access network: cloud RAN), an ultra-dense network (ultra-dense network) , Device to Device communication (D2D), wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), and interference cancellation Technology development is underway.

In addition, in the 5G system, Advanced Coding Modulation (ACM) methods FQAM (Hybrid FSK (frequency shift key) and QAM (quadrature amplitude) Modulation) and SWSC (Sliding Window Superposition Coding) and advanced access technology Filter bank multi carrier (FBMC), non orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) are being developed.

In a communication system, a terminal requires an initial cell selection method and a cell reselection method in IDLE mode for selecting the best base station to access. In addition, in the CONNECTED mode, for handover for the UE to move to a better cell, radio resource observation and cell selection method (radio resource management: RRM measurement), etc. must be performed. In this way, in order to determine a cell and compare the performance between cells, each UE must be able to observe or calculate a measurement value representing each cell or a value derived from the measurement. To this end, in LTE, different base stations reserve orthogonal resources in a shared frequency band using Omni-beam and transmit a cell specific reference signal using this, and the UE measures the received signal of each cell. Get the century (RSRP).

In addition, in a next-generation communication system that considers beamforming, different base stations rotate using different beams to transmit reference signals of each cell and each beam to different resources, and the terminal Various methods are needed for deriving one representative value corresponding to the cell by using the measurement values for a plurality of beams transmitted from one cell.

In addition, when each base station transmits two or more types of reference signals generated by different signal generation rules using two or more types of beams having different beam areas, coverages, transmission periods, etc., one representative corresponding to the cell A method of deriving a value has not been previously studied.

The present disclosure relates to a next-generation wireless communication system, and in particular, a system and method for performing cell measurement and mobility management operations using signals transmitted through beamforming in a beamforming-based system including one or more base stations and one or more terminals , and to the device.

In addition, the present disclosure relates to a beam measurement, a beam measurement report, and a handover start condition procedure in a wireless system in which a base station and a terminal using multiple antennas exist.

The present disclosure discloses a beam observed and measured by a beam measurement subject (terminal) in a system and environment using beamforming, particularly beamforming using multiple antennas, among wireless communication systems in which a base station and a terminal using multiple antennas exist. A method of deriving a representative value of a beam using subject (base station) using information and a trigger condition for transmitting a beam measurement report using the derived representative value of a beam using subject (base station) are proposed.

The present disclosure discloses a beam measurement value reported by a beam measurement subject (terminal) in a system and environment using beamforming, particularly beamforming using multiple antennas, among wireless communication systems in which a base station and a terminal using multiple antennas exist. Alternatively, a trigger condition for the beam user (base station) to transmit a signal for additional beam measurement to the corresponding beam measurement subject (terminal) is proposed using a representative value of the beam user (base station), whether a specific condition is satisfied, or the like.

The present disclosure discloses a beam measurement value reported by a beam measurement subject (terminal) in a system and environment using beamforming, particularly beamforming using multiple antennas, among wireless communication systems in which a base station and a terminal using multiple antennas exist. Alternatively, the beam user (base station) exchanges information with the adjacent beam user (base station) related to the report of the beam measurement subject (terminal) using the representative value of the beam user (base station), whether a specific condition is satisfied, etc. A procedure is proposed so that an adjacent beam user (base station) can also transmit a signal for additional beam measurement.

<How to transmit/receive two or more different types of reference signals>

11 to 13 are diagrams illustrating a method for transmitting different types of reference signals according to an embodiment of the present disclosure.

Referring to FIG. 11 , different types of reference signals (RS) may have the same period as 1100 , and may be transmitted using different frequency bands on the same time resource.

Alternatively, referring to FIG. 12 , different types of reference signals (RS) may have the same period as in 1210 , and may be transmitted on different time resources and using the same frequency band.

Alternatively, referring to FIG. 13 , different types of reference signals (RS) may have different periods as shown in 1310 , and may be transmitted on different time resources and using the same frequency band.

In addition, different types of reference signals (RS) may have different periods and may be transmitted using the same or different sequences in the same or different time and frequency resources.

<How the terminal calculates the cell measurement value>

Signals having different beam characteristics inevitably have significantly different received signal strength and transmission performance. For example, in the case of a wider beam, since power is distributed, when a terminal in the same position receives a signal, its reception signal strength (RSRP) and reception signal quality ( a channel quality indicator (CQI), reference signal received quality (RSRQ), signal-to-interference ration (SINR), and signal-to-noise ratio (SNR)) are inevitably low.

As such, when the base station(s) in the cell, the antenna(s) in the cell, or the transmission point(s) in the cell transmit different reference signals having different beam characteristics, the UE may measure different reference signals. It goes without saying that the reference signal measurement values measured in this way may show a relative difference according to the beam characteristics, as described above.

14 is a diagram illustrating a method in which a terminal calculates a measurement value of a cell in which the corresponding signals are transmitted using different reference signals according to an embodiment of the present disclosure;

Referring to FIG. 14 , the terminal may receive and measure all observable reference signals (S1410). Then, the terminal may classify the received reference signals for the same type of reference signals (S1420). For example, the UE may distinguish the received sync signals (synchronizaiton signals: SS), cell specific RSs, and beam specific RSs. Also, it goes without saying that the UE may classify signals having the same sequence generation rule/function by distinguishing them from other signals.

Then, the UE may calculate a cell representative value using the classified reference signal measurement value (S1430).

Thereafter, the UE may select an idle mode cell or perform RRM measurement using the cell representative value (S1440).

15 is a diagram illustrating a method of classifying measured signals according to the same type of reference signals and calculating a representative value of one cell using the measured values according to an embodiment of the present disclosure.

Referring to FIG. 15 , the terminal may classify the received signal by type. In addition, the UE that has distinguished the different signals may calculate a cell representative value 1500 using the measured values of the divided signals, and use the calculated cell representative value for IDLE mode cell selection or CONNECTED mode RRM measurement, etc.

Various methods may be considered for a method of calculating a cell representative value using a measurement result of one type of signals transmitted through beams having the same characteristic. For example, a method of summing, averaging, weighted summing, or weighted averaging of the measured values may be used. Also, the measured value may be a value obtained by applying L1 filtering or L3 filtering to a measurement result measured by sweeping the base station beam and the terminal beam. At this time, the measured value may be calculated as one value through a method such as summing, averaging, weighted summing, or weighted average before and after L1 filtering or before and after L3 filtering, and a cell representative value can be calculated through a subsequent process have. Also, the measurement value may be measured for each beam pair, for the same base station beam, or for the same terminal beam. These methods may be equally used as a method of calculating a cell representative value using only one type of signals considered in this patent.

16 is a diagram illustrating a method of calculating a cell representative value using all reference signals measured according to an embodiment of the present disclosure.

Referring to FIG. 16 , the method of calculating the cell representative value 1600 using all the measurable beams by the UE is, for example, summing the beam with the highest signal strength, N beams with good signal strength, or all beams. , average, weighted summation, weighted average 1610, etc. may be used. In this case, the above-described methods may be used for calculating the measurement value for each beam and calculating the cell representative value.

17 is a diagram illustrating a method of calculating a cell representative value according to an embodiment of the present disclosure.

Referring to FIG. 17 , the UE recognizes the types of classified reference signals, and may calculate a cell representative value by selecting one or more types of reference signals among them.

Specifically, the terminal may select the reference signal type 1 ( 1710 ) and calculate the cell representative value 1700 using measurement values of reference signals transmitted through various beams included in the corresponding type. Here, as a method of calculating a cell representative value using only beams included in the same type of reference signal, it goes without saying that the above-described methods may be used.

Referring to FIG. 17 , the rule used by the terminal to select a specific type of reference signal and calculate the representative value of the corresponding cell has already been determined in a system including the terminal and the base station, so that there is no need for special information exchange and signal transmission. There may be rules that the terminal and the base station know in advance. A rule for selecting such a reference signal may be determined by considering the same as one of the following examples or overlapping one or more examples:

If the type of reference signal beam prioritized by the standard is observed and measured, the UE can calculate the cell representative value only with the reference signal beam of the type. For example, when a beam specific reference signal (Beam RS, Additional RS, Beamformed demodulation RS (DM-RS), channel state indicator (CSI)-RS (CSI-RS), etc.) is measured, the UE only uses the corresponding reference signal type. can be used to calculate cell representative values.

As another method, when a reference signal type having a relatively narrow beam width is observed and measured than other types of reference signals, the terminal prioritizes the reference signal type having the narrowest beam width and selects the corresponding standard A cell representative value can be calculated using only the signal type.

As another method, when a reference signal type having a relatively wider beam width than other types of reference signals is observed and measured, the terminal prioritizes the reference signal type having the widest beam width and selects the corresponding reference signal type. A cell representative value may be calculated using only the reference signal type.

As another method, when a reference signal type that is relatively more frequently transmitted than other types of reference signals is observed and measured, the terminal prioritizes the most frequently transmitted reference signal type and uses only the reference signal type to calculate the cell representative value.

As another method, when a relatively more sparsely transmitted (sparse) reference signal type is observed and measured than other types of reference signals, the terminal prioritizes the least transmitted reference signal type and uses only the corresponding reference signal type to calculate the cell representative value.

As another method, when a reference signal type transmitted over a relatively wider area than other types of reference signal is observed and measured, the terminal prioritizes the reference signal type transmitted over the widest area and the corresponding reference signal Cell representative values can be calculated using only the type.

As another method, when a reference signal type transmitted in a relatively narrower area (smaller coverage) is observed and measured compared to other types of reference signals, the terminal prioritizes the reference signal type transmitted to the narrowest area and the corresponding reference signal Cell representative values can be calculated using only the type.

In another embodiment, the UE may manage mobility with respect to different base stations (serving and target) using only reference signals simultaneously supported by two base stations.

In addition, in FIG. 17 , in order for the terminal to select a specific type of reference signal, the base station may transmit a certain signal and participate in the determination (config).

18 and 19 show an example of a signal that a base station transmits to a terminal and can use to calculate a cell measurement value according to an embodiment of the present disclosure.

Referring to FIG. 18 , various pieces of information for a method 1820 in which the base station provides one preferred reference signal type 1810 to the terminal and determines a cell representative value by using the reference signal, for example, a cell representative The number of beams (1, K, All) to be used to determine the value, information on how to select a beam (for example, an index can indicate whether to select an arbitrary beam or a beam with good performance) , the type of the cell representative value calculation formula (sum, average, weighted sum with different weights for different K beams) and the like can be transmitted.

The index for each cell representative value calculation method may be known in advance by the base station and the terminal as shown in Table 9 below. In the case of weighted summation, as shown in FIG. 20 , the base station must also include weights for transmission.

[Table 9] Derivation index in the base station transmission signal for measuring the cell representative value of the terminal

(Derivation index for cell level measurement)

Alternatively, with reference to FIG. 19 , alternatively, the base station provides the indices (1910, 1920, 1930) of the reference signal types to the terminal in a preferred order and uses the reference signal to determine the cell representative value. Various pieces of information (1940, 1950, 1960), for example, the number of beams (1, K, All) to be used to determine a cell representative value, information on how to select a beam (for example, whether to select an arbitrary beam) Alternatively, whether to select a beam with good performance may be indicated by an index), a type of a cell representative value calculation formula (sum, average, weighted sum with different weights for different K beams), etc. may be included and transmitted. The index of each reference signal type may be known in advance by the base station and the terminal as shown in Table 10 below.

[Table 10] Reference signal index for cell representative value measurement of the terminal

(RS index for cell level measurement)

The information may be included as a part of any RRC message as an information element, or may be included as a part of any MAC message as a media access control (MAC) control element (CE), and any PHY message as a physical (PHY) element may be included as part of

20 is a diagram illustrating an example in which weights are included in signals transmitted from a base station to a terminal and transmitted according to an embodiment of the present disclosure.

Referring to FIG. 20 , the base station provides the preferred type of reference signal (2010) to the terminal, and information for a method of determining a cell representative value (eg, the number of beams to be used in this figure (2020) and cell Information on the method 2030 for determining the representative value) may be transmitted to the terminal. However, the scope of the present embodiment is not limited thereto, and information used in FIGS. 18 and 19 may be included. In addition, when the method of determining the cell representative value in FIG. 20 is a weighted average or weighted summation, the base station may transmit each weight value 2040 to the terminal. 21 is a diagram for explaining a method for a UE to calculate a cell representative value for each RS through a separate procedure from different RSs according to an embodiment of the present disclosure.

Referring to FIG. 21 , the UE may calculate a cell representative value for each RS through separate procedures without mixing or selecting different beam measurement information received from different types of RSs. In this case, the filtering and cell representative value calculation formulas for different types of RS may be the same or different.

At this time, if different filtering and cell representative value calculation formulas are used for different types of RS, the base station transmits this information to the terminal, and the terminal may perform filtering and cell representative value calculation using this information.

22 is a diagram illustrating a method of controlling a change in mobility using different types of reference signals according to an embodiment of the present disclosure.

Referring to FIG. 22 , the terminal may report the measurement result of reference signal type 1 in step S2210.

According to the measurement result, the base station may determine whether transmission of the reference signal type 2 is necessary in step S2220.

When it is determined that transmission of the reference signal type 2 is necessary, the base station may transmit the reference signal type 2 to the terminal in step S2230. Then, the base station may receive the measurement result of the reference signal type 2 in step S2240.

The base station may determine whether a mobility change (handover, etc.) is necessary in step S2250 based on the measurement result, and if necessary, may request or instruct a mobility change in step S2260.

In this case, the base station may determine a cell representative value using values measured using different types of reference signals according to the method described above and a method to be described later, and determine whether a mobility change is required using this value.

23 to 28, a different number of beam measurement signals for different types of reference signals are selected in the order of good performance, respectively, up to N1, N2, ..., Nk, and multiplied by different weights to represent cells Examples of deriving values are shown. Weight may be positive or negative, and may be greater than or less than 1.

Referring to FIG. 23, representative values (2310, 2320) for each RS are calculated through separate procedures for different types of reference signals, and one cell representative value (2330) is calculated using the representative values. indicate how to decide. Referring to FIG. 23 , the UE may determine the cell representative value by multiplying the measured value determined for each reference signal by a weight.

Referring to FIG. 24 , a method of determining a cell representative value 2420 by multiplying each beam measurement signal by the same weight 2410 for the same type of reference signal is shown. Also, different weights (weight 1 and weight 2) may be applied to different types of reference signals. However, the weight 1 and the weight 2 may have the same value.

Referring to FIG. 25 , a method of deriving a cell representative value by selecting a specific number of beam measurement signals for different types of reference signals and multiplying a representative value for each RS by a weight is shown. Referring to FIG. 25, the UE selects N1 best beams 2510 and N2 best beams 2520 for additional RS and idle mode RS, respectively, and can determine representative values (2530, 2540) for each RS. and a cell representative value 2550 can be calculated by applying a weight to the representative value for each RS.

Referring to FIG. 26 , a specific number of beam measurement signals are selected for different types of reference signals, each of the selected beam measurement signals is multiplied by a weight to calculate a representative value for RS, and the representative value for each RS is Shows how to derive cell representative values by multiplying weights. In this figure, a case in which weights applied to each of the beam measurement signals are different from each other will be described as an example, but the present disclosure is not limited thereto, and the weights may be the same for each RS.

Referring to FIG. 26, the UE selects N1 best beams 2610 and N2 best beams 2620 for additional RS and idle mode RS, respectively, and multiplies each of the selected beam measurement signals with weights (2630, 2640) Determine a representative value (2650, 2660) for each RS. In addition, the UE may calculate the cell representative value 2670 by applying a weight to the representative value for each RS.

27 illustrates another method of selecting a different number of beam measurement signals for different types of reference signals and deriving a cell representative value by multiplying them by different weights according to an embodiment of the present disclosure.

Referring to FIG. 27, the UE selects N1 best beams 2710 and N2 best beams 2720 for additional RS and idle mode RS, respectively, and multiplies each of the selected beam measurement signals with weights (2730, 2740). can And the UE may calculate the cell representative value 2770 using the result. In this figure, a case in which weights applied to each of the beam measurement signals are different from each other will be described as an example, but the present disclosure is not limited thereto, and the weights may be the same for each RS.

28 is a diagram illustrating a method of deriving a cell representative value by multiplying all beam measurement signals by different weights with respect to different types of reference signals according to an embodiment of the present disclosure.

Referring to FIG. 27 , the UE may multiply all beam measurement signals by weights (2810, 2820) for the additional RS and the idle mode RS. And the UE may calculate the cell representative value 2830 using the result. In this figure, a case in which weights applied to each of the beam measurement signals are different from each other will be described as an example, but the present disclosure is not limited thereto, and the weights may be the same for each RS.

29 is a diagram illustrating a method of controlling a change in mobility using different types of reference signals according to an embodiment of the present disclosure.

Referring to FIG. 29 , the terminal may receive reference signal type 1 from the first base station and the second base station (S2910, S2920), and may report the measurement result to the first base station (S2930).

Based on the measurement result, the first base station may determine whether transmission of the reference signal type 2 is necessary (S2940), and if it is determined that it is necessary, may request the second base station for the reference signal type (S2950).

Accordingly, the second base station can recognize the need to transmit the reference signal type 2 (S2960), and the first base station and the second base station can transmit the reference signal type 2 to the terminal (S2970, S2975). Accordingly, the terminal may transmit the measurement result for the reference signal type 2 to the first base station (S2980), and the first base station determines whether a mobility change is necessary based on the result (S2985), and if necessary, the terminal A mobility change request or indication may be transmitted (S2990).

<Measurement report triggering events using measurement values of different RSs>

[event NR1]

[event NR2]

The following tables are for explaining the description based on the event (NR3), and it is preferable to be understood as content that is interconnected with each other.

[event NR3]

[event NR4]

The following tables are for explaining the description based on the event (NR5), and it is preferable to be understood as content that is interconnected with each other.

[event NR5]

The following tables are for explaining the description based on the event (NR6), and it is preferable to be understood as content that is interconnected with each other.

[event NR6]

The following tables are for explaining the description based on the event (NR7), and it is preferable to be understood as content that is interconnected with each other.

[event NR7]

30 is a diagram illustrating a terminal according to an embodiment of the present disclosure.

Referring to FIG. 30 , the terminal 3000 may include a transceiver 3010 and a control unit 3030 for transmitting and receiving signals.

The terminal 3000 may transmit and/or receive a signal, information, message, etc. through the transceiver 3010 .

The controller 3030 may control the overall operation of the terminal 3000 . The controller 3030 may include at least one processor. The controller 3030 may control the operation of the terminal described in the present disclosure. For example, the controller 3030 may control a signal flow between blocks to perform an operation according to the above-described flowchart.

31 is a diagram illustrating a base station according to an embodiment of the present disclosure.

Referring to FIG. 31 , the base station 3100 may include a transceiver 3110 and a control unit 3130 for transmitting and receiving signals.

The base station 3100 may transmit and/or receive a signal, information, message, etc. through the transceiver 3110 . The controller 3130 may control the overall operation of the base station 3100 . The controller 3130 may include at least one processor.

The controller 3130 may control the operation of the base station described in the present disclosure.

For example, the controller 3130 may control a signal flow between blocks to perform an operation according to the above-described flowchart.

<Third embodiment>

Meanwhile, in the present disclosure, in a situation in which a reference signal (hereinafter referred to as idle mode RS) for both the idle mode terminal and the connected mode terminal and the connected mode RS only for the connected mode terminal coexist, the terminal performs RRM measurement through the idle mode RS. After performing (a) the terminal requests the connected mode RS at an appropriate time, or (b) the base station transmits the connected mode RS at an appropriate time, the terminal reports the connected mode RS measurement result to the base station.

32 is a diagram illustrating an initial connection operation according to an embodiment of the present disclosure.

Referring to FIG. 32 , in the present disclosure, in an RRC connection establishment procedure, (a) when a terminal requests connected mode RS transmission to a base station, (b) when a base station transmits connected mode RS, and (c) a base station We propose a method for allocating resources for reporting the connected mode RS measurement result of the UE. The operation proposed in the present disclosure is based on FIG. 32 .

That is, according to the present disclosure, based on the random access procedure and RRC connection procedure shown in S3210 to S3260 of FIG. 32, the terminal requests transmission of common mode RS, the base station transmits the connected mode RS, and the base station transmits the connected mode RS of the terminal. It is possible to allocate resources for reporting mode RS measurement result. Specific details will be described below.

<Connected mode RS request>

When transmitting the random access preamble (S3220), the UE may request connected mode RS transmission from the base station through preamble classification.

To this end, the base station classifies the random access preamble into two groups, and the terminal that has transmitted the random access preamble belonging to one group understands that it has requested a connected mode RS, and the terminal that has transmitted the random access preamble belonging to the other group is in connected mode. I understand that RS is not requested.

If the terminal requests the connected mode RS, the terminal continuously performs blind decoding on the PDCCH so that the base station understands the resource for transmitting the connected mode RS and resource allocation information for the terminal to transmit the measurement result report. .

Alternatively, when transmitting the RRC connection request message (S3240), the UE sets a bit indicating a connected mode RS transmission request to 1 in the corresponding message to request connected mode RS transmission from the base station.

If the corresponding bit is set to 0, the base station understands that the terminal does not request connected mode RS transmission to the base station.

Alternatively, when transmitting the RRC connection setup complete message (S3260), the UE sets a bit indicating a connected mode RS transmission request in the message to 1 and requests the base station to transmit the connected mode RS.

<Connected mode RS resource allocation>

When transmitting a random access response message (S3230), the base station allocates a resource for transmitting the connected mode RS in the message.

Alternatively, when transmitting the RRC connection setup message (S3250), the base station allocates a resource for transmitting the connected mode RS in the corresponding message.

The resource referred to herein is a time/frequency resource and may be expressed as a resource block index or the like.

Alternatively, the base station allocates a resource for transmitting the connected mode RS through a separate signal, for example, PDCCH Downlink Control Information (DCI).

< Connected mode RS measurement result feedback resource allocation>

When transmitting the random access response message (S3230), the base station allocates a resource for reporting the connected mode RS measurement result in the corresponding message.

Alternatively, when transmitting the RRC connection setup message (S3250), the base station allocates a resource for reporting the connected mode RS measurement result in the corresponding message.

Alternatively, the base station allocates a resource for reporting the connected mode RS measurement result through a separate signal, for example, PDCCH Downlink Control Information (DCI).

< Connected mode RS measurement result Feedback>

When transmitting the RRC connection request message (S3240), the UE may include connected mode RS measurement result information in the message.

Here, the connected mode RS measurement result includes the N beam indexes having the highest signal strength after the connected mode RS measurement and the corresponding signal strength (RSRP or RSRQ). Here, N may be set by the base station through an RRC message or the like.

Alternatively, when transmitting the RRC connection setup complete message (S3260), the UE may include connected mode RS measurement result information in the message.

The base station transmits connected mode RS measurement result information to the base station through a separate signal, for example, a physical uplink control channel (PUCCH), a physical uplink shared channel (PUSCH), and the like.

33 is a diagram illustrating a handover operation according to an embodiment of the present disclosure.

Referring to FIG. 33, in the present disclosure, in the handover procedure, (a) when the terminal requests connected mode RS transmission to the base station, (b) when the base station transmits the connected mode RS, and (c) when the base station transmits the connected mode RS of the terminal We propose a method for allocating resources for measurement result reporting. The operation proposed in the present disclosure is based on FIG. 33 .

That is, according to the present invention, based on the handover procedure shown in steps S3310 to S3370 of FIG. 33, the terminal requests connected mode RS transmission to the base station, the base station transmits the connected mode RS, and the base station reports the connected mode RS measurement result of the terminal resources can be allocated for Specific details will be described below.

<Connected mode RS request>

When transmitting the measurement report (S3320), the UE sets a bit indicating a connected mode RS transmission request to 1 in the corresponding message and requests the base station to transmit the connected mode RS.

Alternatively, when transmitting the random access preamble (S3350), the UE requests the base station to transmit the connected mode RS through preamble classification. The source gNB and the target gNB may initiate a handover request and response in step S3330.

Alternatively, when transmitting the RRC connection reconfiguration complete message (S3370), the UE sets a bit indicating a connected mode RS transmission request to 1 in the corresponding message to request connected mode RS transmission from the base station.

<Connected mode RS resource allocation>

When transmitting an RRC connection reconfiguration (mobility control information or handover command) message (S3340), the base station allocates a resource for transmitting the connected mode RS in the message.

Alternatively, when transmitting a random access response message (S3360), the base station allocates a resource for transmitting the connected mode RS in the message.

Alternatively, the base station allocates a resource for transmitting the connected mode RS through a separate signal, for example, PDCCH DCI.

<Connected mode RS measurement result feedback resource allocation>

When transmitting the RRC connection reconfiguration (mobility control information or handover command) message (S3340), the base station allocates a resource for reporting the connected mode RS measurement result in the corresponding message.

Alternatively, when transmitting the random access response message (S3360), the base station allocates a resource for reporting the connected mode RS measurement result in the corresponding message.

Alternatively, the base station allocates a resource for reporting the connected mode RS measurement result through a separate signal, for example, PDCCH Downlink Control Information (DCI).

<Connected mode RS measurement result Feedback>

When the UE transmits the RRC connection reconfiguration complete message (S3370), the connected mode RS measurement result information is included in the corresponding message.

Alternatively, the terminal transmits the connected mode RS measurement result information to the base station through a separate signal, for example, PUCCH or PUSCH.

As another example, the operation proposed in the present disclosure is based on FIG. 34 .

34 illustrates an operation according to an embodiment of the present disclosure.

Referring to FIG. 34 , the terminal of the present disclosure may request the source base station to receive an additional RS from the target base station in the step of transmitting the RRC connection setup request (S3410), and the source base station requests the target base station to schedule the additional RS. and (S3420), and a response may be received (S3430). Accordingly, the source base station may transmit a response message to the RRC connection setup request to the terminal (S3440), and additional RS scheduling information may be included in the message. In this case, the additional RS may mean, for example, a CSI-RS.

Accordingly, the terminal may receive RS from the source base station and the target base station (S3450, S3460).

In the present disclosure, a system in which a base station uses a synchronization signal (SS) and a CSI-RS is considered. Here, the SS may include both a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS). Also, SS corresponds to a cell-specific signal and CSI-RS may be a cell-specific signal, a UE-specific signal, or a UE group-specific signal.

In the present disclosure, a situation in which a UE accesses a base station for the first time (initial access) or a handover from a serving base station to a target base station is considered. In addition, the present disclosure considers a situation in which the base station uses the SS signal when determining whether to perform initial access or handover of the terminal.

In this situation, the present disclosure proposes an operation in which the terminal is quickly allocated a beam to be used for data communication from an accessed base station or a handover target base station after performing initial access or handover. In general, a relatively wide beam may be used for the beam through which the SS is transmitted in order to reduce the required time for beam sweeping or for other reasons. However, a relatively narrow beam may be used for a beam through which CSI-RS or data is transmitted to obtain a high beamforming gain. Therefore, the base station or the terminal determines whether to perform initial access or handover through the SS transmitted through the wide beam, and the terminal receives the CSI-RS from the connected base station or target base station to determine the narrow beam to be used for data communication.

Also, since the terminal does not know when to access the base station, the SS can be viewed as an always-on signal that is always transmitted. However, the CSI-RS may or may not be viewed as an always-on signal depending on the overhead of time and frequency resources required for transmission. In the present disclosure, it is assumed that the SS is an always-on signal and the CSI-RS is not an always-on signal. That is, the CSI-RS assumes that the base station can determine whether to transmit as needed.

In the present disclosure, it is assumed that the SS is transmitted through a relatively wide beam and the CSI-RS is transmitted through a relatively narrow beam. A mapping relationship can be established. In the present disclosure, it is assumed that such a relationship is established, and examples thereof are shown in the table below.

[Table 11]

So far, the assumptions considered in the present disclosure have been identified. The present disclosure is not limited thereto and may be generalized to a method of operating it during initial access and handover in a system in which two types of RS (Reference Signal) are mixed.

35 to 41 illustrate a method of determining a beam to be used for data transmission and reception in a handover procedure according to an embodiment of the present disclosure.

First, the operation of the present disclosure will be described in a situation in which the terminal performs handover from the serving base station to the target base station.

1. Referring to FIG. 35, the serving base station provides measurement configuration information to the terminal (S3510).

A. Here, the measurement configuration information includes the frequency to be measured by the terminal and the measurement report triggering condition.

2. The terminal performs measurement according to the measurement configuration information received from the base station.

A. Here, the UE measures the signal strength or quality of the SS transmitted by the serving base station and the target base station.

B. In the present disclosure, it is assumed that the base station transmits SS while sweeping a plurality of beams directed in different directions. Therefore, the UE can classify the SS transmitted through different beams into the received time and frequency resources.

3. As a result of comparing the signal strength of the serving base station with that of the target base station, if an event is detected in which the signal strength of the target base station is better than the signal intensity of the serving base station by an offset (S3520), the terminal transmits a measurement report to the serving base station (S3530).

A. The UE may transmit/receive (S3520) a Scheduling Request (SR), a Buffer Status Report (BSR), a UL grant, etc. with the base station in order to transmit a measurement report.

B. In the present disclosure, the A3 event has been described as an example, but the same principle may be applied even when other events are applied.

4. When the serving base station receives the measurement report from the terminal, the serving base station transmits a handover request to the target base station (S3550) to perform admission control.

A. If the target base station can accommodate the terminal, it transmits an acknowledgment (ACK) for the handover request to the serving base station (S3550) to provide the necessary information when the terminal accesses the target base station.

B. The information required when the terminal accesses the target base station includes a dedicated RAP (Random Access Preamble) transmitted by the terminal to synchronize uplink with the target base station, and C-RNTI required for data transmission/reception between the terminal and the target base station .

5. Serving The base station provides the necessary information when the terminal accesses the target base station by sending a handover command to the terminal (S3560).

A. Here, the handover command may include dedicated RAP and C-RNTI information received from the target base station through the handover request ACK.

6. The terminal transmits (S3570) a random access preamble (RAP) to the target base station based on the information included in the handover command. This is an operation in which the terminal controls transmission (TX) timing and power to perform uplink transmission/reception with the target base station.

7. After the target base station receives the RA preamble transmitted by the terminal, it transmits a random access response (RAR) in response.

A. After receiving the RAP, the target base station informs the UE of the TX timing and power adjustment level through RAR, and requests to transmit the RAP again if necessary. Also, after the uplink synchronization is achieved in this way, the base station allocates a UL grant so that the terminal can transmit a handover confirm (S3580).

8. After receiving the RAR, the UE with uplink synchronization transmits a handover confirm to the target eNB through the UL grant included therein (S3590).

A. Through this, the UE completes handover from the serving base station to the target base station.

This handover operation is designed to suit the situation where the base station uses only one RS. This is not suitable for the situation considered in the present disclosure, that is, the determination of whether to perform handover is based on the SS transmitted through the wide beam, but is not suitable for the situation in which a narrow beam is used when actually transmitting and receiving data. This is because, despite the completion of the handover, the terminal has not determined through which narrow beam the target base station should transmit and receive data.

In the present disclosure, the UE determines whether to perform handover through measurement on SS transmitted through a wide beam, and performs measurement on CSI-RS transmitted through narrow beam during the handover procedure so that the UE can use the narrow beam to be used by the target base station as soon as possible. Explain the behavior you found. From now on, each of several embodiments will be described.

[Handover: proposed 1]

An embodiment of Handover: proposed 1 will be described with reference to FIG. 36 .

1. Serving The base station provides measurement configuration information to the terminal (S3610).

2. The terminal performs measurement according to the measurement configuration information received from the base station.

A. Here, the UE measures the signal strength or quality of the SS transmitted by the serving base station and the target base station.

3. As a result of comparing the signal strength of the serving base station with that of the target base station, if an event is detected in which the signal strength of the target base station is better than the signal intensity of the serving base station by an offset (S3620), the terminal transmits a measurement report to the serving base station (S3640).

4. When the serving base station receives the measurement report from the terminal, the serving base station transmits a handover request to the target base station (S3650) to perform admission control.

5. Serving The base station provides the necessary information when the terminal accesses the target base station by sending a handover command to the terminal (S3660).

6. The terminal transmits the RAP to the target base station based on the information included in the handover command (S3670).

A. Here, the target base station can receive the terminal's RAP while sweeping a wide beam used for SS transmission. In this case, the target base station memorizes the wide beam that received the terminal's RAP and uses it in the next step. If the target base station receives the terminal's RAP through a plurality of wide beams, the target base station memorizes the wide beam with the highest signal strength among them and uses it in the next step.

7. After receiving the RA preamble transmitted by the terminal, the target base station transmits the RAR in response to it (S3680).

A. After the target base station receives the RAP, it informs the terminal of the TX timing and power adjustment level through the RAR, and if necessary, the target base station requests to transmit the RAP again. Also, after this uplink synchronization is achieved, the base station allocates a UL grant so that the terminal can transmit handover confirm.

B. Additionally, in the present disclosure, the UE transmits the CSI-RS configuration information 3600 along with the RAR to the UE. Details of the CSI-RS configuration will be described after the entire operation is described.

8. The target base station transmits the CSI-RS through a plurality of narrow beams corresponding to the wide beams from which the RAP is received (S3690).

9. The UE measures the signal strength or quality of the CSI-RS transmitted by the target base station based on the CSI-RS configuration information.

10. After receiving the RAR, the UE with uplink synchronization transmits a handover confirm to the target base station through the UL grant included therein (S3691).

A. When the UE transmits the handover confirm, it feedbacks (3601) the measurement result for the CSI-RS. When transmitting this, the UE utilizes the UL grant included in the RAR.

B. Through this, the UE completes handover from the serving base station to the target base station.

11. The target base station selects a narrow beam to be used by the terminal based on the CSI-RS feedback of the terminal and informs the terminal of this (S3692).

In the present disclosure, the target base station provides CSI-RS configuration information to the terminal. This is similar to CSI-RS configuration information used in LTE. Additionally, the target base station needs to inform the UE of beam information for transmitting the CSI-RS. Accordingly, the target base station may include the SS beam information on which the RAP is received or CSI-RS beam information corresponding thereto in the CSI-RS configuration information. Tables 11 and 12 below show antenna port information for transmitting CSI-RS in CSI-RS configuration information, time and frequency resource information, subframe information, power information, wide SS beam information for receiving RAP, and narrow CSI-RS transmission An example in which CSI-RS beam information, a CSI-RS transmission period, and a time during which the CSI-RS configuration is valid are included is shown.

[Table 12]

Tables 13 to 16 below show a method for determining a CSI-RS transmission period, an offset, and a resource location in CSI-RS configuration information used in the present disclosure. The CSI-RS transmission period, offset, resource location, and power information (p-C) may be determined according to the CSI-RS configuration information and the table below.

[Table 13] CSI reference signal subframe configuration

[Table 14] Mapping from CSI reference signal configuration to (k', l') for normal cyclic prefix

Note: n _s '=n _s mod 2. Configurations 0 - 19 for normal subframes are available for frame structure types 1, 2 and 3. Configurations 20 - 31 and configurations for special subframes are only available for frame structure type 2.

[Table 15] Mapping from CSI reference signal configuration to (k', l') for extended cyclic prefix.

Note: n _s '=n _s mod 2. Configurations 0 - 15 for normal subframes are available for both frame structure type 1 and type 2. Configurations 16 - 27 and configurations for special subframes are only available for frame structure type 2.

[Table 16]

In addition, in the present disclosure, the UE feedbacks (3701) the measurement result for the CSI-RS to the target base station. Table 17 below shows the contents of feedback from the terminal.

[Table 17]

[Handover: proposed 2]

An embodiment of Handover: proposed 2 will be described with reference to FIG. 37 .

1. Referring to FIG. 37 , the serving base station provides measurement configuration information to the UE (S3710).

2. The terminal performs measurement according to the measurement configuration information received from the base station.

A. Here, the UE measures the signal strength or quality of the SS transmitted by the serving base station and the target base station.

3. As a result of comparing the signal strength of the serving base station with that of the target base station, if an event is detected in which the signal strength of the target base station is better than the signal intensity of the serving base station by an offset (S3720), the terminal transmits a measurement report to the serving base station (S3740).

4. When the serving base station receives the measurement report from the terminal, the serving base station transmits a handover request to the target base station (S3750) to perform admission control.

5. Serving The base station provides the necessary information when the terminal accesses the target base station by sending a handover command to the terminal (S3760).

6. The terminal transmits the RAP to the target base station based on the information included in the handover command (S3770).

A. Here, the target base station can receive the terminal's RAP while sweeping a wide beam used for SS transmission. In this case, the target base station memorizes the wide beam that received the terminal's RAP and uses it in the next step. If the target base station receives the terminal's RAP through a plurality of wide beams, the target base station memorizes the wide beam with the highest signal strength among them and uses it in the next step.

7. After the target base station receives the RA preamble transmitted by the terminal, it transmits the RAR in response to it (S3780).

A. After the target base station receives the RAP, it informs the terminal of the TX timing and power adjustment level through the RAR, and if necessary, the target base station requests to transmit the RAP again. Also, after this uplink synchronization is achieved, the base station allocates a UL grant so that the terminal can transmit handover confirm.

B. Additionally, in the present disclosure, the UE transmits the CSI-RS configuration information 3700 together with the RAR to the UE. Details of the CSI-RS configuration information have been described above.

8. The target base station transmits the CSI-RS through a plurality of narrow beams corresponding to the wide beams on which the RAP is received (S3790).

9. The UE measures the signal strength or quality of the CSI-RS transmitted by the target base station based on the CSI-RS configuration information.

10. After receiving the RAR, the UE with uplink synchronization transmits a handover confirm to the target base station through the UL grant included therein (S3791).

A. Through this, the UE completes handover from the serving base station to the target base station.

11. The target base station allocates a UL grant for receiving feedback of the CSI-RS measurement result to the terminal (S3792).

12. The UE feedbacks (S3793) the CSI-RS measurement result by using the allocated UL grant.

13. The target base station selects a narrow beam to be used by the terminal based on the CSI-RS feedback of the terminal and informs the terminal of this (S3794).

[Handover: proposed 3]

An embodiment of Handover: proposed 3 will be described with reference to FIG. 38 .

1. Referring to FIG. 38 , the serving base station provides measurement configuration information to the UE (S3810).

2. The terminal performs measurement according to the measurement configuration information received from the base station.

A. Here, the UE measures the signal strength or quality of the SS transmitted by the serving base station and the target base station.

3. As a result of comparing the signal strength of the serving base station with the signal strength of the target base station, if an event is detected in which the signal strength of the target base station is better than the signal intensity of the serving base station by an offset (S3820), the terminal transmits a measurement report to the serving base station (S3840).

4. When the serving base station receives the measurement report from the terminal, the serving base station transmits a handover request to the target base station (S3850) to perform admission control.

A. In this disclosure, the serving base station transmits information included in the measurement report to the target base station. The information includes the SS beam index of the target base station measured by the terminal and the signal strength corresponding thereto.

B. In addition, the target base station determines the CSI-RS configuration based on the measurement report received from the serving base station and delivers it to the serving base station through handover request ACK.

5. Serving The base station provides the necessary information when the terminal accesses the target base station by sending a handover command to the terminal (S3860).

A. Additionally, in the present disclosure, CSI-RS configuration information 3800 is transmitted to the UE together with a handover command. Details of the CSI-RS configuration information have been described above.

6. The terminal transmits the RAP to the target base station based on the information included in the handover command (S3870).

A. Here, the target base station can receive the terminal's RAP while sweeping a wide beam used for SS transmission. In this case, the target base station memorizes the wide beam that received the terminal's RAP and uses it in the next step. If the target base station receives the terminal's RAP through a plurality of wide beams, the target base station memorizes the wide beam with the highest signal strength among them and uses it in the next step.

7. After the target base station receives the RA preamble transmitted by the terminal, it transmits the RAR in response to it (S3880).

A. After receiving the RAP, the target base station informs the UE of the TX timing and power adjustment level through RAR, and requests to transmit the RAP again if necessary. In addition, after the uplink synchronization is achieved in this way, the base station allocates a UL grant so that the terminal can transmit handover confirm.

8. The target base station transmits the CSI-RS through a plurality of narrow beams corresponding to the wide beam receiving the RAP (S3890).

9. The UE measures the signal strength or quality of the CSI-RS transmitted by the target base station based on the CSI-RS configuration information.

10. After receiving the RAR, the UE with uplink synchronization transmits a handover confirm to the target base station through the UL grant included therein (S3891).

A. When transmitting the handover confirm, the UE feeds back the measurement result 3801 for the CSI-RS. When transmitting this, the UE utilizes the UL grant included in the RAR.

B. Through this, the UE completes handover from the serving base station to the target base station.

11. The target base station selects a narrow beam to be used by the terminal based on the CSI-RS feedback of the terminal and informs the terminal thereof (S3892).

[Handover: proposed 4]

An embodiment of Handover: proposed 4 will be described with reference to FIG. 39 .

1. Referring to FIG. 39, the serving base station provides measurement configuration information to the terminal (S3910).

2. The terminal performs measurement according to the measurement configuration information received from the base station.

A. Here, the UE measures the signal strength or quality of the SS transmitted by the serving base station and the target base station.

3. As a result of comparing the signal strength of the serving base station with the signal strength of the target base station, if an event is detected in which the signal strength of the target base station is better than the signal intensity of the serving base station by an offset (S3920), the terminal transmits a measurement report to the serving base station (S3940).

4. When the serving base station receives the measurement report from the terminal, the serving base station transmits a handover request to the target base station (S3950) to perform admission control.

A. In this disclosure, the serving base station transmits information included in the measurement report to the target base station. The information includes the SS beam index of the target base station measured by the terminal and the signal strength corresponding thereto.

B. In addition, the target base station determines the CSI-RS configuration based on the measurement report received from the serving base station and delivers it to the serving base station through handover request ACK.

5. Serving The base station provides the necessary information when the terminal accesses the target base station by sending a handover command to the terminal (S3960).

A. Additionally, in the present disclosure, CSI-RS configuration information 3900 is transmitted to the UE together with a handover command. Details of the CSI-RS configuration information have been described above.

6. The target base station transmits the CSI-RS through a plurality of narrow beams corresponding to the wide beams having the largest signal strength measured by the terminal included in the measurement report (S3970).

7. The UE measures the signal strength or quality of the CSI-RS transmitted by the target base station based on the CSI-RS configuration information.

8. The terminal transmits the RAP to the target base station based on the information included in the handover command (S3980).

9. After the target base station receives the RA preamble transmitted by the terminal, it transmits the RAR in response to it (S3990).

A. After receiving the RAP, the target base station informs the UE of the TX timing and power adjustment level through RAR, and requests to transmit the RAP again if necessary. In addition, after the uplink synchronization is achieved in this way, the base station allocates a UL grant so that the terminal can transmit handover confirm.

10. After receiving the RAR, the UE with uplink synchronization transmits a handover confirm to the target eNB through the UL grant included therein (S3991).

A. When transmitting the handover confirm, the UE feeds back the measurement result 3901 for the CSI-RS. When transmitting this, the UE utilizes the UL grant included in the RAR.

B. Through this, the UE completes handover from the serving base station to the target base station.

11. The target base station selects a narrow beam to be used by the terminal based on the CSI-RS feedback of the terminal and informs the terminal of this (S3992).

[Handover: proposed 5]

An embodiment of Handover: proposed 5 will be described with reference to FIG. 40 .

1. Referring to FIG. 40, the serving base station provides measurement configuration information to the terminal (S4010).

2. The terminal performs measurement according to the measurement configuration information received from the base station.

A. Here, the UE measures the signal strength or quality of the SS transmitted by the serving base station and the target base station.

3. As a result of comparing the signal strength of the serving base station with that of the target base station, if an event is detected in which the signal strength of the target base station is better than the signal intensity of the serving base station by an offset (S4020), the terminal transmits a measurement report to the serving base station (S4040).

4. When the serving base station receives the measurement report from the terminal, the serving base station transmits a handover request to the target base station (S4050) to perform admission control.

A. In this disclosure, the serving base station transmits information included in the measurement report to the target base station. The information includes the SS beam index of the target base station measured by the terminal and the signal strength corresponding thereto.

B. In addition, the target base station determines the CSI-RS configuration based on the measurement report received from the serving base station and delivers it to the serving base station through handover request ACK.

5. Serving The base station provides the necessary information when the terminal accesses the target base station by sending a handover command to the terminal (S4060).

A. Additionally, in the present disclosure, CSI-RS configuration information 4000 is transmitted to the UE together with a handover command. Details of the CSI-RS configuration information have been described above.

6. The terminal transmits a random access preamble (RAP) to the target base station based on the information included in the handover command (S4070).

A. Here, the target base station can receive the terminal's RAP while sweeping a wide beam used for SS transmission. In this case, the target base station memorizes the wide beam that received the terminal's RAP and uses it in the next step. If the target base station receives the terminal's RAP through a plurality of wide beams, the target base station memorizes the wide beam with the highest signal strength among them and uses it in the next step.

7. After receiving the RA preamble transmitted by the terminal, the target base station transmits a random access response (RAR) in response to it (S4080).

A. After receiving the RAP, the target base station informs the UE of the TX timing and power adjustment level through RAR, and requests to transmit the RAP again if necessary. In addition, after the uplink synchronization is achieved in this way, the base station allocates a UL grant so that the terminal can transmit handover confirm.

B. In addition, the present disclosure includes an indicator 4001 for instructing the UE to measure the CSI-RS to the RAR.

8. If the target base station sets the CSI-RS measurement command indicator included in the RAR to 1, the target base station transmits the CSI-RS through a plurality of narrow beams corresponding to the wide beams that have received the RAP (S4090).

A. If the target base station sets the CSI-RS measurement command indicator included in the RAR to 0, the target base station does not transmit the CSI-RS.

9. In addition, when the CSI-RS measurement command indicator included in the RAR is set to 1, the UE determines the signal strength or quality of the CSI-RS transmitted by the target base station based on the CSI-RS configuration information transmitted along with the handover command. measure

A. If the CSI-RS measurement command indicator included in the RAR is set to 0, the target base station does not transmit CSI-RS, so the UE does not perform CSI-RS measurement related operations.

10. After receiving the RAR, the UE with uplink synchronization transmits a handover confirm to the target eNB through the UL grant included therein (S4091).

A. When the UE transmits the handover confirm, it feeds back the measurement result 4002 for the CSI-RS. When transmitting this, the UE utilizes the UL grant included in the RAR.

B. Through this, the UE completes handover from the serving base station to the target base station.

11. The target base station selects a narrow beam to be used by the terminal based on the CSI-RS feedback of the terminal and informs the terminal of this (S4092).

[Handover: proposed 6]

An embodiment of Handover: proposed 8 will be described with reference to FIG. 41 .

1. Referring to FIG. 41, the serving base station provides measurement configuration information to the terminal (S4110).

2. The terminal performs measurement according to the measurement configuration information received from the base station.

A. Here, the UE measures the signal strength or quality of the SS transmitted by the serving base station and the target base station.

3. As a result of the UE comparing the signal strength of the serving BS with that of the target BS, if an event is detected in which the signal strength of the target BS is better than the signal strength of the serving BS by an offset (S4120), the MS sends a measurement report to the serving BS (S4140).

4. When the serving base station receives the measurement report from the terminal, the serving base station transmits a handover request to the target base station (S4150) to perform admission control.

A. In this disclosure, the serving base station transmits information included in the measurement report to the target base station. The information includes the SS beam index of the target base station measured by the terminal and the signal strength corresponding thereto.

B. In addition, the target base station determines the CSI-RS configuration based on the measurement report received from the serving base station and delivers it to the serving base station through handover request ACK.

5. Serving The base station provides the necessary information when the terminal accesses the target base station by sending a handover command to the terminal (S4160).

A. Additionally, in the present disclosure, CSI-RS configuration information 4100 is transmitted to the UE together with a handover command. Details of the CSI-RS configuration information have been described above.

6. The terminal transmits the RAP to the target base station based on the information included in the handover command (S4170).

A. Here, the target base station can receive the terminal's RAP while sweeping a wide beam used for SS transmission. In this case, the target base station memorizes the wide beam that received the terminal's RAP and uses it in the next step. If the target base station receives the terminal's RAP through a plurality of wide beams, the target base station memorizes the wide beam with the highest signal strength among them and uses it in the next step.

7. After receiving the RA preamble transmitted by the terminal, the target base station transmits the RAR in response to it (S4180).

A. After receiving the RAP, the target base station informs the UE of the TX timing and power adjustment level through RAR, and requests to retransmit the RAP if necessary. In addition, after the uplink synchronization is achieved in this way, the base station allocates a UL grant so that the terminal can transmit handover confirm.

B. Additionally, in the present disclosure, by utilizing RAR, the UE may instruct the UE to measure ( 4101 ) only a part of the CSI-RS transmission resources specified in the CSI-RS configuration.

C. Here, the target base station may limit the antenna port through which the CSI-RS is transmitted among information included in the CSI-RS configuration through the RAR and inform the terminal. For example, although the CSI-RS configuration for four antenna ports is configured and transmitted, the UE may be informed through RAR that the CSI-RS will be transmitted using only two antenna ports among them.

D. In addition, the base station transmits after setting the CSI-RS configuration for M SS beams or CSI-RS beam sets, but among them, only CSI-RSs for N (< M) SS beams or CSI-RS beam sets are transmitted. The UE may be informed through RAR.

E. In addition, the base station transmits to the terminal after including M resource blocks in the CSI-RS configuration, but among them, only N (< M) resource blocks are used to transmit the CSI-RS. You can inform the terminal through RAR.

F. In addition, the base station sets M subframe as a period and transmits it to the terminal after including it in the CSI-RS configuration, but in fact, it can inform the terminal through RAR that it will transmit the CSI-RS by setting N (> M) subframe as the period.

G. In this disclosure, CSI-RS configuration information is transmitted together with a handover command. At this time, the target base station sets the CSI-RS configuration based on the signal strength of the target base station included in the measurement report and transmits it to the terminal. However, the UE transmits an uplink RAP after receiving the handover command, and the base station can more accurately determine the CSI-RS beam set corresponding to the SS beam through which the CSI-RS is to be transmitted to the UE by receiving it. Therefore, in the present disclosure, the base station may use a part of the CSI-RS transmission resource included in the CSI-RS configuration information to transmit the CSI-RS beam set corresponding to the RAP reception SS beam.

8. The target base station transmits the CSI-RS through a plurality of narrow beams corresponding to the wide beams from which the RAP is received (S4190).

A. Here, the CSI-RS may be transmitted using only a part of the CSI-RS transmission resources specified in the CSI-RS configuration as indicated by the RAR to the UE.

9. The UE measures the signal strength or quality of the CSI-RS transmitted by the target base station based on the CSI-RS configuration information transmitted along with the handover command and the CSI-RS subset information 4101 included in the RAR.

10. After receiving the RAR, the UE with uplink synchronization transmits a handover confirm to the target base station through the UL grant included therein (S4191).

A. When the UE transmits the handover confirm, it feedbacks 4102 the measurement result for the CSI-RS. When transmitting this, the UE utilizes the UL grant included in the RAR.

B. Through this, the UE completes handover from the serving base station to the target base station.

11. The target base station selects a narrow beam to be used by the terminal based on the CSI-RS feedback of the terminal and informs the terminal of this (S4192).

Next, the operation of the present disclosure will be described in a situation in which the idle mode terminal initially accesses the base station. The initial connection operation is as follows.

[Initial access]

42 is a diagram illustrating a random access operation according to an embodiment of the present disclosure.

An initial connection operation will be described with reference to FIG. 42 .

1. While performing RX beam sweeping, the UE measures the signal strength or quality of each beam for the SS transmitted by the base station through TX beam sweeping.

2. The UE transmits the RAP toward one or more base station beams having the largest signal strength when SS is measured (S4210).

3. When the base station receives the RAP, it transmits the RAR to the terminal using one or more base station beams having the largest signal strength (S4220).

A. A UL grant is included in the RAR so that the UE can transmit the RRC connection request.

4. After receiving the RAR, the UE transmits an RRC connection request to the base station through the UL grant included therein (S4230).

5. The base station receives the RRC connection request from the terminal and transmits the RRC connection setup to the terminal (S4240).

6. The terminal receives the RRC connection setup from the base station and transmits the RRC connection setup complete to the base station (S4250).

A. Through this, the terminal completes the initial access to the base station.

Since this is the same as the initial access operation defined in LTE, a detailed description of each message will be omitted. This existing initial access operation is designed to suit the situation where the base station uses only one RS. This is not suitable for the situation considered in the present disclosure, that is, the determination of whether to perform initial access is based on the SS transmitted through the wide beam, but is not suitable for the situation in which a narrow beam is used when actually transmitting and receiving data. This is because even though the initial access has been completed, the terminal has not determined through which narrow beam to transmit and receive data to the base station.

In the present disclosure, the UE determines whether to perform initial access through measurement on the SS transmitted through the wide beam, and performs measurement on the CSI-RS transmitted through the narrow beam during the initial access procedure to enable the UE to use a narrow beam for the base station. Ask them to describe the action they found quickly. Hereinafter, various embodiments will be respectively described.

43 to 47 are diagrams illustrating a method of determining a beam to be used for data transmission and reception in a random access procedure according to various embodiments of the present disclosure.

[Initial access: proposed 1]

An embodiment of Initial access: proposed 1 will be described with reference to FIG. 43 .

1. Referring to FIG. 43, while performing RX beam sweeping, the UE measures signal strength or quality for each beam for SS transmitted by the base station through TX beam sweeping.

2. The UE transmits the RAP toward one or more base station beams having the largest signal strength when SS is measured (S4310).

3. When the base station receives the RAP, it transmits the RAR to the terminal using one or more base station beams having the greatest signal strength (S4320).

A. The RAR includes a UL grant so that the UE can transmit an RRC connection request.

B. Additionally, in the present disclosure, CSI-RS configuration information 4300 is transmitted to the UE together with the RAR. Details of the CSI-RS configuration have been described above.

4. The base station transmits the CSI-RS through a plurality of narrow beams corresponding to the wide beam receiving the RAP or the beam having the highest signal strength among the plurality of wide beams receiving the RAP (S4330).

5. The UE measures the signal strength or quality of the CSI-RS transmitted by the base station based on the CSI-RS configuration information.

6. After receiving the RAR, the UE transmits an RRC connection request to the base station through the UL grant included therein (S4340).

A. When the UE transmits the RRC connection request, it feedbacks the measurement result for the CSI-RS (4301).

7. The base station receives the RRC connection request from the terminal and transmits the RRC connection setup to the terminal (S4350).

A. Here, the RRC connection setup may be transmitted using a wide beam used for RAR transmission or a beam having the largest signal strength measured by the UE among narrow beams included in CSI-RS feedback.

8. The terminal receives the RRC connection setup from the base station and transmits the RRC connection setup complete to the base station (S4360).

A. Through this, the terminal completes the initial access to the base station.

[Initial access: proposed 2]

An embodiment of Initial access: proposed will be described with reference to FIG. 44 .

1. Referring to FIG. 44, the UE measures the signal strength or quality of each beam for the SS transmitted by the base station through TX beam sweeping while performing RX beam sweeping.

2. The UE transmits the RAP toward one or more base station beams having the largest signal strength when SS is measured (S4410).

3. When the base station receives the RAP, it transmits the RAR to the terminal using one or more base station beams having the greatest signal strength (S4420).

A. The RAR includes a UL grant so that the UE can transmit an RRC connection request.

B. Additionally, in the present disclosure, CSI-RS configuration information 4400 is transmitted to the UE together with the RAR. Details of the CSI-RS configuration have been described above.

4. The base station transmits the CSI-RS through a plurality of narrow beams corresponding to a wide beam receiving RAP or a beam having the highest signal strength among a plurality of wide beams receiving RAP (S4430).

5. The UE measures the signal strength or quality of the CSI-RS transmitted by the base station based on the CSI-RS configuration information.

6. After receiving the RAR, the UE transmits an RRC connection request to the base station through the UL grant included therein (S4440).

7. The base station receives the RRC connection request from the terminal and transmits the RRC connection setup to the terminal (S4450).

8. The terminal receives the RRC connection setup from the base station and transmits the RRC connection setup complete to the base station (S4460).

A. When the UE transmits the RRC connection setup complete, it feedbacks (4401) the measurement result for the CSI-RS.

B. Through this, the terminal completes the initial access to the base station.

[Initial access: proposed 3]

An embodiment of Initial access: proposed 3 will be described with reference to FIG. 45 .

1. Referring to FIG. 45, while performing RX beam sweeping, the UE measures the signal strength or quality of each beam for SS transmitted by the base station through TX beam sweeping.

2. The UE transmits the RAP toward one or more base station beams having the largest signal strength when SS is measured (S4510).

3. When the base station receives the RAP, it transmits the RAR to the terminal using one or more base station beams having the greatest signal strength (S4520).

A. The RAR includes a UL grant so that the UE can transmit an RRC connection request.

B. Additionally, in the present disclosure, CSI-RS configuration information 4500 is transmitted to the UE together with the RAR. Details of the CSI-RS configuration have been described above.

4. The base station transmits the CSI-RS through a plurality of narrow beams corresponding to the wide beam receiving the RAP or the beam having the highest signal strength among the plurality of wide beams receiving the RAP (S4530).

5. The UE measures the signal strength or quality of the CSI-RS transmitted by the base station based on the CSI-RS configuration information.

6. After receiving the RAR, the UE transmits an RRC connection request to the base station through the UL grant included therein (S4540).

7. The base station receives the RRC connection request from the terminal and transmits the RRC connection setup to the terminal (S4550).

8. The terminal receives the RRC connection setup from the base station and transmits the RRC connection setup complete to the base station (S4560).

A. Through this, the terminal completes the initial access to the base station.

9. The base station allocates a UL grant for receiving CSI-RS feedback to the terminal, and the terminal feedbacks the CSI-RS measurement result to the base station through the UL grant (S4570).

[Initial access: proposed 4]

An embodiment of Initial access: proposed 4 will be described with reference to FIG. 46 .

1. Referring to FIG. 46, the UE measures the signal strength or quality of each beam for the SS transmitted by the base station through TX beam sweeping while performing RX beam sweeping.

2. The UE transmits the RAP toward one or more base station beams having the largest signal strength when SS is measured (S4610).

3. When the base station receives the RAP, it transmits the RAR to the terminal using one or more base station beams having the greatest signal strength (S4620).

A. The RAR includes a UL grant so that the UE can transmit an RRC connection request.

4. After receiving the RAR, the UE transmits an RRC connection request to the base station through the UL grant included therein (S4630).

5. The base station receives the RRC connection request from the terminal and transmits the RRC connection setup to the terminal (S4640).

A. Additionally, in the present disclosure, CSI-RS configuration information 4600 is transmitted to the UE together with the RAR. Details of the CSI-RS configuration have been described above.

6. The base station transmits the CSI-RS through a plurality of narrow beams corresponding to the wide beam receiving the RAP or the beam having the highest signal strength among the plurality of wide beams receiving the RAP (S4650).

7. The UE measures the signal strength or quality of the CSI-RS transmitted by the base station based on the CSI-RS configuration information.

8. The terminal receives the RRC connection setup from the base station and transmits the RRC connection setup complete to the base station (S4660).

A. When the UE transmits the RRC connection setup complete, it feedbacks (4601) the measurement result for the CSI-RS.

B. Through this, the terminal completes the initial access to the base station.

[Initial access: proposed 5]

An embodiment of Initial access: proposed 5 will be described with reference to FIG. 47 .

1. Referring to FIG. 47, while performing RX beam sweeping, the UE measures the signal strength or quality of each beam for the SS transmitted by the base station through TX beam sweeping.

2. The UE transmits the RAP toward one or more base station beams having the greatest signal strength when SS is measured (S4710).

3. When the base station receives the RAP, it transmits the RAR to the terminal using one or more base station beams having the greatest signal strength (S4720).

A. The RAR includes a UL grant so that the UE can transmit an RRC connection request.

4. After receiving the RAR, the UE transmits an RRC connection request to the base station through the UL grant included therein (S4730).

5. The base station receives the RRC connection request from the terminal and transmits the RRC connection setup to the terminal (S4740).

A. Additionally, in the present disclosure, CSI-RS configuration information 4700 is transmitted to the UE together with the RAR. Details of the CSI-RS configuration have been described above.

6. The base station transmits the CSI-RS through a plurality of narrow beams corresponding to the wide beam receiving the RAP or the beam having the highest signal strength among the plurality of wide beams receiving the RAP (S4750).

7. The UE measures the signal strength or quality of the CSI-RS transmitted by the base station based on the CSI-RS configuration information.

8. The terminal receives the RRC connection setup from the base station and transmits the RRC connection setup complete to the base station (S4760).

A. Through this, the terminal completes the initial access to the base station.

9. The base station allocates a UL grant for receiving CSI-RS feedback to the terminal, and the terminal feedbacks the CSI-RS measurement result to the base station through the UL grant (4701).

In addition, the embodiments disclosed in the present specification and drawings are merely provided for specific examples to easily explain the contents of the present invention and help understanding, and are not intended to limit the scope of the present invention. Accordingly, the scope of the present invention should be construed as including all changes or modifications derived from the technical spirit of the present invention in addition to the embodiments disclosed herein as being included in the scope of the present invention.

<Fourth embodiment>

In the LTE system, a multi-carrier method in which a plurality of component carriers (CC) are bundled and operated, such as carrier aggregation (CA) and dual connectivity (DC), is introduced to support broadband. When up to 32 CCs are interlocked (aggregation), a bandwidth of 640 MHz based on 20 MHz CC can be supported. However, if a method such as LTE CA is applied to support ultra-wideband, such as 1 GHz, in the 5G NR (New Radio) system, the number of CC combinations to be used by the terminal increases exponentially, and the size of the terminal's capability report increases. And, the UE has no choice but to operate within a limited CC combination. In addition, as the number of CCs in CA increases, the reception complexity of the terminal and the control complexity of the base station also increase. However, despite these problems of CA or DC, CA or DC shows high flexibility in resource usage compared to a single carrier. This is because the extension band can be changed with SCell Addition/Release and resource transmission/reception for other CCs can be scheduled with cross-carrier scheduling.

In addition, in the 5G system, energy-efficient operation is defined with the main goal of improving the power efficiency [bit/J] of the terminal and base station networks by more than 1000 times. To this end, it is necessary to control the size of the operating band of the terminal in order to solve the possibility of additional power consumption due to the wideband transmission scheme, which is essential for mmW operation in the high frequency band.

The present invention proposes a technique for an operation method of a base station and a terminal to achieve Energy Efficiency key performance indicators (KPI) discussed in 3GPP RAN 5G SI. More specifically, the present invention relates to Layer 1/2 layer operations of a terminal and a base station in a mobile communication system. More specifically, it relates to a method and apparatus for changing an operating band of a terminal in order to reduce power consumption of the terminal when a base station intends to perform ultra-wideband signal transmission/reception with the terminal.

The present invention proposes a control and setting method for ultra-wideband transmission and reception in a 5G mobile communication system. In particular, a method for scheduling, handover, and power saving in ultra-wideband is considered. Various services (or slices) such as enhanced Mobile BroadBand (eMBB), Ultra Reliable and Low Latency Communication (URLLC), and enhanced Machine Type Communication (eMTC) are expected to be supported in the 5G mobile communication system. This can be understood in the same context that the 4G mobile communication system, LTE, supports voice-specific services such as VoIP (Voice over Internet Protocol) and BE (Best Effort) services. In addition, it is expected that various numerologies will be supported in the 5G mobile communication system. This is specifically indicated by a difference in subcarrier spacing or Transmission Time Interval (TTI). Therefore, it is expected that TTI of various lengths will be supported in the 5G mobile communication system. This can be seen as one of the characteristics of the 5G mobile communication system, which is very different from the support of only one type of TTI (1 ms) in LTE standardized so far. If the 5G mobile communication system supports a much shorter TTI (eg 0.1 ms) than the 1 ms TTI of LTE, it is expected to be of great help in supporting URLLC that requires a short delay time. Note that in the present invention, numerology is used as a term that plays a role such as subcarrier spacing, subframe length, symbol/sequence length, and the like. Also, the UE may be configured with different BWs in different numerology areas. The base station may be used interchangeably with various terms such as gNB, eNB, NB, and BS. The terminal may be used interchangeably with various terms such as UE, MS, and STA.

48 is a diagram illustrating an LTE scalable BW system according to an embodiment of the present disclosure.

49 is a diagram illustrating a 5G NR flexible BW system according to an embodiment of the present disclosure.

Referring to FIG. 48 , LTE introduces a scalable BW concept to support various BWs. According to FIG. 48, the LTE system supports terminals having various BWs (eg, 5/10/20 MHz) having the same center frequency. For example, in the case of a UE supporting 5 MHz for UE1 4810 and 10 MHz for UE2 4820, the LTE base station configures a control channel appropriately and transmits a control signal so that both UE1 and UE2 can receive it. However, in this method, when the total available band of the base station is very large, that is, in the ultra-wideband, the resources available to the terminal of a relatively small band are extremely limited. For example, when the UE3 4830 of FIG. 48 operates at the edge of the band used by the base station, the UE3 4830 cannot distinguish and receive the control signal of the base station.

Referring to FIG. 49 , in the 5G NR communication system, an operating band should be flexibly set as shown in FIG. 49 . That is, after the UE succeeds in RRC Connection Setup through the access BW 4900 set from the synchronization signal reception and system information (SI) acquisition information, the operating band is configured according to the control of the base station. It is possible to switch from a relatively narrow BW 4910 to a wide BW 4920 . The terminal may contribute to the improvement of control signal performance by receiving the control signal of the base station in a wide band, or may improve resource efficiency by performing data transmission/reception (DL or UL).

In addition, in the 5G NR communication system, even in a band not supported by the existing scalable BW system, the terminal must be able to transmit and receive important control signals to maintain the connection with the base station. An important control signal is transmitted through the PCell as a Signaling Radio Bearer (SRB) in the case of LTE. In addition, the PCell transmits and receives control signals for scheduling and hybrid automatic-repeat-request (HARQ) procedures in the PCell itself and the SCell. All LTE PCells or SCells can be viewed as one independent Cell. In addition, for each cell, a separate MAC entity and a corresponding Link Adaptation and HARQ entity are required. However, in the 5G NR Single Carrier communication system, the entire band corresponds to one cell. In addition, the functions of PCell for terminal access, connection setup/maintenance, and data transmission/reception should be basically provided.

On the other hand, even if the base station is operated in the ultra-wideband, the terminal can transmit/receive only a partial band at a time due to limited implementation and complexity. In order to operate in a band larger than the maximum available band (Capable BW) of the terminal, it has to be divided in time to operate. The base station divides the ultra-wideband into bands or subbands of an appropriate size for ease of management, and sets various functions (control signal transmission/reception, data signal transmission/reception, RS, measurement, scheduling, measurement) in a specific band to the UE. , Link Adaptation, modulation coding scheme (MCS), HARQ, etc.). In addition, based on the band, the terminal may determine and receive the structure of the control channel and the reference signal.

50 is a diagram illustrating various band division schemes in a 5G NR Flexible BW system according to an embodiment of the present disclosure.

Referring to FIG. 50 , in case A, UE1 (UE1) 5000 may operate only in a part of an available band, not the entire band, due to the band configuration of a fixed size.

In case of UE2 (UE2) 5010 in Case B, since the maximum available band is smaller than the band 5011 of band 4 set by the base station, UE2 5010 cannot be supported in band 4.

When the band unit is minimized as in Case C, since the band to be used by the terminal is expressed as a bundle of small bands, the terminal 5020 having a band of various sizes can be supported. On the other hand, too many bands may increase the overload.

Therefore, like Case D, a method in which the band size can be freely set is useful.

In the present disclosure, in order to improve the problem of the method in which the base station divides the entire band into bands up to Case A-D of FIG. 50 and sets it to the terminal, the base station sets bands of different sizes for each terminal, but from the standpoint of the system, the subbands of the same size Consider a method in which a band set by the terminal can be expressed by a combination of (sub-band). In addition, instead of performing independent scheduling, Link Adaptation, MCS, and HARQ procedures like the existing CA in the subband divided from the system point of view, one scheduling, Link Adaptation, MCS, and HARQ procedure is performed in the band set from the terminal point of view.

The structure of the physical layer control channel should be designed in a scalable structure for one or a plurality of subbands in one band. This means that at least a terminal having a band that can be expressed as a multiple of a subband within the band can be supported. The size of a band, which is a bundle of subbands, is determined by at least one of channel characteristics between the terminal and the base station, numerology, the size of the control subband, and the minimum packet size. The UE performs one MAC function set (scheduling, MCS, HARQ, etc.) for one service.

Functions that can be provided by the system structure proposed in this disclosure can be considered as follows.

Configuration of control/RS/CSI report/HARQ feedback per band

· Self-/cross-band scheduling

Band-aggregation to transmit single transport block

· Cross-band HARQ retransmission

· RRM measurement

Power saving with adaptive BW

[Configuration of control/RS/CSI report/HARQ feedback per band]

The base station may inform the terminal by expressing the range (start, size, or center frequency and bandwidth) of the band as a multiple of the basic unit (RB or subband) when configuring the band. Since the position and range of the band is a part of one carrier on which the network system operates, the base station may set the band to the terminal as a frequency offset for the center frequency of the entire carrier band and the bandwidth of the band. Alternatively, the base station may set a band in the terminal with a frequency offset for the center frequency in which the synchronization signal detected by the terminal is located and the bandwidth of the band. On the other hand, the center frequency of the carrier band understood by the terminal is always the center frequency of the synchronization signal detected by the terminal, or the same as the center frequency information of the carrier indicated by the SI connected to the synchronization signal detected by the terminal, or the terminal is It may be the same as the center frequency information of the carrier indicated by the base station in the RRC connection establishment procedure. The UE understands the range of the band as a system band. Therefore, even if bands of different ranges are allocated, the UE must be designed to receive a signal according to the same reception rule.

For example, the position of the reference signal (RS) or the control channel transmitted by the base station should be determined based on the start and size of the band set for the terminal. In addition, the location of the CSI report or HARQ feedback transmitted by the terminal should also be determined based on the start and size of the band configured for the terminal. On the other hand, when receiving the configuration of a plurality of bands, the terminal may be additionally configured by the base station whether to share the HARQ process for the plurality of bands or to separate each band.

A band configured to be monitored by the UE is referred to as a primary band (p-band), and the UE monitors in a resource area other than the p-band before a separate control/configuration is given in the p-band. may not be performed.

The s-band operates selectively according to configuration through the p-band, and the p-band and the s-band may be referred to as a first radio frequency (RF) band and a second RF band, respectively, according to an embodiment. Also, the p-band may be switched to an active state through an RRC message or MAC CE among at least one or more configured band candidates. Also, the s-band may be switched to an active state through an RRC message or MAC CE or DCI among at least one or more configured band candidates. In the same way, the base station may instruct the terminal to a deactivation signal or message through an RRC message or MAC CE or DCI to switch one or more bands from an active state to an inactive state (deactivated). In the present disclosure, active band and p-band are used interchangeably with similar meanings, but in detail, when configuring p-band, the DL band and the UL band must be combined. Therefore, p-band is an active band, but not all active bands are p-band. Also, p-band is not deactivated except for a separate band conversion procedure. In the case of TDD, the frequency positions of the DL band and the UL band of the p-band may be the same.

The P-band configuration includes at least one DL band and one or more UL bands, and the base station may indicate the p-band configuration to the UE. When the UE reports to the base station including RF information in the UE capability report, the base station may configure p-bands for different RFs of the UE.

- Hereinafter, an operation associated with a band switch/activation instruction in a single or multiple active bands will be described.

The UE may monitor one or more of one or more configured bands at the same time according to RF conditions. Therefore, it is advantageous in terms of scalability that the band indication of the base station is commonly applied to terminals in different RF conditions. However, the base station needs to know in advance other RF conditions of the terminal through the terminal's capability report. Otherwise, when Band#1 gives an activation instruction for Band#2 to a certain terminal, it is not known whether Band#1 has been deactivated due to the RF restriction of the terminal, so there is a possibility of malfunction.

When a terminal operating as a single active band receives an indication of a band activation indication from a base station, the previous band is deactivated while switching to the indicated band. When a terminal operating with multiple active bands receives an indication of a band activation indication from a base station, it activates the indicated band and maintains the band in use by activating it.

However, band setting according to the terminal's Capability Report may cause malfunction. Therefore, the base station should be able to set the maximum number of active bands of the terminal and clearly indicate the deactivation of the bands.

The activation/deactivation operation rule for the band may be preset or set by the base station/network according to any one of the following two methods. In addition, this operation can be equally applied even when band switch/activation occurs in conjunction with a cross-band scheduling indication in addition to a separate band activation indication of the base station.

a) Multiple Active Bands are set, but each Active Band can only be switched to a different Deactivated Band. Therefore, changing the number of active bands is only possible with RRC.

b) Set Multiple Active Bands, and give Activated/Deactivated instructions for each band. Since the number of active bands can be changed, the base station must operate so that the maximum number of active bands of the terminal is not exceeded or all bands are deactivated. If the base station instructs to exceed the maximum active band, the terminal 1) deactivates the first activated band among the previous active bands, 2) deactivates the last activated band, or 3) the lowest band in the order of the band index. Deactivates the band of 4) Deactivates the lowest band according to the priority between bands determined by the base station, 5) Deactivates the band arbitrarily determined by the terminal; may be operated by at least one of In addition, the band to be deactivated may be set to exclude the P-band.

- Hereinafter, a procedure for determining a movement time including retuning latency when activating a band with DCI or MAC CE will be described.

The RF retuning time may vary depending on the terminal's active band switching condition and the relationship between the switching bands. The base station may set the time required for switching to another band compared to one band (eg, P-band) as RRC to the terminal based on the terminal's capability report. When the terminal does not follow this setting, the terminal may reject the band switching for each band.

In the case where the base station instructs the band to be switched to DCI, 1) the UE may consider the switching delay time from the DCI reception time (subframe/slot/minislot) already set to RRC to completing the switch. Therefore, the terminal can monitor the control channel starting from the earliest effective control channel in the activated band after the switching delay time from the DCI reception time based on the band ID included in the DCI. Alternatively, 2) DCI may include a switching delay time k from the DCI reception time (subframe/slot/minislot) to completion of switching along with the Band ID. Accordingly, the terminal can monitor the control channel starting from the earliest effective control channel after the time point determined according to the k value.

In the case where the base station instructs to switch the band to the MAC CE, 1) the UE considers the switching time already set in RRC based on the Band ID included in the MAC CE, and the HARQ ACK success time for MAC CE reception (subframe) After the transition delay time from /slot/minislot) to completion of the conversion, the control channel can be monitored from the earliest effective control channel in the activated band. Alternatively, 2) the UE may consider the switching delay time already set in RRC. After the UE determines the band switching based on the Band ID included in the MAC CE, the UE transmits the indication to the PHY (subframe/slot/minislot) after the transition delay time until the transition is completed. Control channels can be monitored starting from the earliest effective control channel in the activated band. Alternatively, 3) MAC CE may include a switching delay time k from a successful MAC CE reception time (subframe/slot/minislot) to completion of switching along with a Band ID. Therefore, the UE can monitor the control channel from the earliest effective control channel in the activated band after the transition delay time from the successful MAC CE reception time (subframe/slot/mini-slot) to completion of the transition. Alternatively, 4) the switching delay time k from the time (subframe/slot/minislot) of transmitting the HARQ ACK for MAC CE reception success along with the Band ID to the MAC CE until the switching is completed may be included. Therefore, the UE monitors the control channel starting from the earliest effective control channel in the activated band after the transition delay time from the successful HARQ ACK time (subframe/slot/mini-slot) to the completion of the conversion for the MAC CE reception success time. can do; The terminal follows at least one of the above-described operations.

[Self-/cross-band scheduling]

51 is a diagram illustrating a self/cross-band scheduling operation according to an embodiment of the present disclosure.

Referring to FIG. 51 , the base station uses a data channel 5120 in the same subband or a data channel 5140 in another subband through control sub-bands 5110, 5130, and 5150 in the p-band. A control channel 5160 in another subband may be scheduled.

The base station may control transmission and reception of signals through the control channel or data channel of the terminal through a control sub-band within the p-band set for each terminal. The base station may indicate a DL (downlink) or UL (uplink) data transmission/reception area by self-band data scheduling or cross-band data scheduling. In addition, the base station may indicate a change in the location or size of a control sub-band within the same band through self-band control scheduling. In addition, the base station may indicate the location or size of an additional control sub-band in another band through cross-band control scheduling.

When the position or size of the second control sub-band is indicated by the first control sub-band, the UE checks whether the first control sub-band and the second control sub-band are simultaneously monitored. If so, the UE may simultaneously receive a control signal through both control sub-bands. Otherwise, since it means that the UE monitors only the first control sub-band, a delay for RF retuning of a certain or more is required to monitor the second control sub-band.

In general, in the case of uplink scheduling, the base station may indicate a predetermined delay value (eg, 4 ms) or a separate delay value to the terminal through the control subband.

In the system considered in the present disclosure, in the case of cross-band scheduling that may require a bandwidth change even for downlink scheduling, in general, a downlink shared channel (PDSCH) for data transmission and reception in the same subframe as a downlink control channel (PDCCH). On the other hand, it is necessary to separately indicate a specific subframe that follows temporally.

This is because processing time is required for retuning the RF and BB (Baseband) circuits as the position of the used band is rapidly changed. That is, in consideration of the available band information included in the capability report of the terminal and the extent to which the base station changes the use band of the terminal by the control of the base station, the base station transmits and receives the downlink signal after the delay time set after transmission of the control signal. should be instructed to do. The delay time may be included in each control signal, or the base station may preset at least one delay time value during capability negotiation and connection setup procedure of the terminal. Since the terminal's used band partially overlaps, and the delay when the terminal's used band is completely changed compared to the case where only the bandwidth is changed, the base station transmits the delay time through every control signal in consideration of this situation, By sending indexes for two or more delay values through a control signal, the UE may perform downlink reception operation after an appropriate delay.

Meanwhile, the base station may configure an asymmetric p-band having different bands (position, size) in downlink and uplink for one terminal. However, since the main control function smoothly operates only when both downlink and uplink are supported in the p-band, the UE understands it as one p-band even if other bands are allocated.

[Adaptive BW method and procedure for power saving]

In the LTE system, a power saving mode (PSM) and DRX are provided to save power. The PSM mainly refers to a state in which only tracking area update (TAU) or routing area update (RAU) is performed and paging from the base station is not received. It is almost similar to power off, but since the terminal is still registered in the network, there is no need to re-attach the network or re-establish the PDN connection.

DRX is divided into idle mode DRX and connected mode DRX. According to Idle mode DRX, that is, Idle-DRX, the Idle mode terminal does not receive a signal from the base station except for the time (Paging Frame Number and Paging Occasion) for periodically monitoring the paging signal. At this time, since the terminal does not have an RRC connection with the network, the network does not have context information of the terminal. The UE is registered with the MME and is considered to reside in the Tracking Area List (TAL). The purpose of connected mode DRX is to reduce power consumption caused by the connected mode terminal monitoring the control signal (PDCCH) of the base station every DL subframe. If the terminal arbitrarily skips monitoring for the DL subframe, it becomes difficult for the base station to control the terminal as desired. Accordingly, the base station and the terminal must perform transmission and reception by the base station in a DL subframe at a predetermined location according to a predetermined agreement.

The LTE Connected DRX operation is briefly described as follows. The base station may set a DRX-related variable among RRC parameters through an RRC connection setup request message or an RRC connection reestablishment request message. DRX-related variables include, for example, DRX cycle, On duration timer, and Inactivity timer. The DRX cycle represents the length of one section in which the UE repeats On and Off, and the On duration timer represents the length of the On section. The length of the off duration can be calculated from the DRX cycle and the on duration timer. These variables are expressed in units of subframes. The basic operation of the terminal is to monitor the DL signal of the PDCCH of the base station during the On period indicated by the On duration timer and do not monitor the DL signal in the PDCCH of the base station in the Off period. Meanwhile, when the UE succeeds in receiving the DL signal in a subframe, the inactivity timer starts from that subframe. Until the inactivity timer expires, the UE must monitor the DL signal on the PDCCH of the base station. Finally, after successfully receiving the DL signal, if the subframe at the time the inactivity timer expires is reached and the subframe belongs to the Off duration, the UE does not monitor the DL signal.

More specifically, C-DRX can be divided into short DRX and long DRX according to the cycle of the DRX cycle. In accordance with the activity of the DL signal, the UE always switches to short DRX in an awake state in every subframe, then to long DRX, and then to a state in which DRX is not performed again after the long DRX cycle is completed. To set this operation, a short DRX cycle timer indicating the number of repetitions of the short DRX cycle is used. In case of Long DRX, the UE switches to the sleep state after one long DRX cycle. The base station may switch the terminal back to short DRX or instruct the start of short or long DRX with the MAC Command Element (CE) in order to maintain the long DRX state of the terminal. Exceptionally, at the time of DL HARQ packet retransmission defined as HARQ RTT (Round Trip Time), the UE must monitor the DL signal regardless of DRX. In addition, when UL HARQ packet retransmission is expected, the UE must monitor the DL control signal, that is, the UL grant during the period set as the DRX retransmission timer.

Short DRX is expressed by the following equation according to LTE:

[(SFN * 10) + subframe number] modulo (shortDRX-Cycle) = (drxStartOffset) modulo (shortDRX-Cycle)

Long DRX is expressed by the following equation according to LTE:

[(SFN * 10) + subframe number] modulo ( longDRX-Cycle ) = drxStartOffset

A similar formula can be used when applying LTE connected mode DRX (C-DRX) to 5G NR.

If LTE C-DRX is applied to 5G NR, the terminal receiving high-speed data traffic monitors the base station's wide band (broadband) DL signal in the On duration and operates not to monitor the DL signal in the Off duration. However, it is not necessary to receive a wideband DL signal in every subframe according to traffic characteristics. For example, in the case of a streaming service, an encoding method for transmitting only image change information between periodic large-capacity information is used. Therefore, in the 5G NR communication system, the size of the bandwidth (BW) of the resource monitored by the terminal should be adaptively varied as needed.

52 to 54 are diagrams illustrating BW expansion and reduction operations by a physical layer control signal according to an embodiment of the present disclosure.

If the variable BW control is performed in the L1 layer, that is, the physical layer, the operations shown in FIGS. 52 to 55 are possible. In order to save power, it is reasonable that the terminal is basically in a narrow BW state and then switches to a wide BW when necessary.

Referring to FIG. 52 , the UE monitors the narrowband control sub-band (CSB#1) 5210 provided by L1 in the RRC connection setup step and receives the L1 signal 5230 indicating BW extension from the base station. If so, the terminal monitors the wideband control sub-band (CSB#2) 5320 in a subframe of a location having a specific interval.

The interval between the time when the BW extension indication control signal is received and the subframe switched to CSB#2 is a) a fixed interval, b) an interval set by the RRC variable, c) an interval set by the L1 control signal, d) the terminal Interval that can be calculated according to the reported BW capability information and the current state of the terminal, e) whether the center frequency of the BW to be switched overlaps; determined according to at least one of

On the other hand, when the terminal continuously requests large-capacity traffic, the BW extension indication control signal must be frequently sent, and in the worst case, half of the subframes have to be serviced in a narrow band due to the limitation of the switching delay. In addition, a load of the terminal and additional power consumption may occur due to frequent BW and RF switching.

Referring to FIG. 53 , an example of further using the BW reduction indication control signal is shown in order to solve the problem of using only the BW expansion indication control signal.

According to this operation, when the terminal receives the BW extension indication control signal 5330 by monitoring the CBS#1 5310, it switches the bandwidth to monitor the CSB#2 5320 and continues to maintain the mode. And, when the terminal receives the BW reduction indication control signal 5360 through the CSB#2 5340, the bandwidth is switched to monitor the CSB#1 5350. However, in this method, when the reception of the BW extension or reduction instruction control signal fails, an error may occur in the operation of the terminal.

For example, the base station sends a BW extension indication control signal 5330 and sends a control signal (DCI) for data transmission/reception to CSB #2 5320 of the indicated subframe, but the terminal sends the BW extension indication control signal 5330 ), since the UE monitors CSB#1, it cannot receive the DCI transmitted through the CSB#2 5320. In this case, the base station does not receive the DCI transmitted through the CSB#2 5320 even though the terminal has successfully received the BW extension indication control signal 5330, or whether the terminal receives the BW extension indication control signal 5330 I don't know if it failed.

In addition, when the UE does not receive a DL signal for a certain period of time due to mismatch of the monitoring band, that is, CSB, it may operate in DRX Off or a problem may occur in the HARQ timeline.

According to the operations shown in FIGS. 54 and 55 , at least by not using the BW reduction indication control signal, the problem of L1 signal reception error can be reduced. That is, after the BW extension, the terminal operates in the wideband, CSB#2 only for a specific time period, and thereafter, it can return to the narrowband, CSB#1.

According to FIG. 54, the base station not only the CSB#2 location 5420 with the BW extension indication control signal 5430 in the CBS#1 5410, but also a duration 5440 for monitoring the CSB#2 is also provided to the terminal. let me know

On the other hand, the base station may preset the time period information for maintaining the wideband in consideration of the capacity and performance of the L1 signal as an RRC variable instead of the L1 signal. However, dynamic control may be limited in the case of presetting with RRC compared to the case of notifying with the L1 signal. Therefore, when notifying with RRC variable, it may be useful to use a timer like the existing DRX inactivity timer rather than a fixed time period.

55 to 58 are diagrams illustrating BW expansion and reduction operations using a physical layer and an RRC control signal according to an embodiment of the present disclosure.

According to FIG. 55, after monitoring CSB#2 indicated by the BW extension indication control signal 5530 in CBS#1 (5510), the UE cannot receive a DL signal from the next CSB#2 (5520) subframe. The RRC setup timer 5540 is started. If the timer expires after 3 subframes without receiving a DL signal, the UE returns to narrowband CSB#1 again in the next subframe. The start time of the timer may be changed.

If the timer value is set to be small, even though the control signal of the base station is actually transmitted to the terminal, the terminal may not continuously receive the base station signal due to deterioration of the channel quality. In this situation, a band mismatch may occur in which the base station transmits a signal in the wideband and the terminal attempts to receive the signal in the narrowband. The base station may start the timer from the point in time when the feedback of the terminal or the scheduled uplink signal does not arrive, or when the event that the uplink signal does not arrive, using a separate timer, satisfies a certain condition. When the timer of the base station expires, the base station transmits a base station signal through a narrowband control channel, that is, CSB#1. In order to support this operation, the location of the On duration for the control channel in the narrowband of the terminal may be preset. That is, the start of the operation in the wideband depends on the L1/MAC signal, and the reception operation of the control channel in the narrowband may follow the DRX cycle determined based on the system time like the existing DRX operation. When the wideband inactivity timer expires according to the inactivity of the control channel in the wideband, the terminal performs retuning in the narrowband and then receives the control channel according to the set DRX On duration.

On the other hand, the interpretation of inactivity may be applied differently depending on the case.

Referring to FIG. 56 , the terminal receives the BW reduction instruction control signal 5630 of the base station in the next subframe after switching to the wideband 5610 according to the BW extension instruction control signal 5620 . This is because the base station has determined that there is no more traffic to send over the broadband.

Here, even if the terminal monitors the narrowband CSB#1, the inactivity timer 5650 set for the RRC may be maintained without immediately expiring. That is, in a state where the terminal cannot directly receive the DL resource allocation control signal in wideband, that is, CSB#2, the operation of the terminal switching between wideband and narrowband by the control signal of the base station or a certain rule affects the inactivity timer. don't give The UE can stop the timer only after receiving the DL resource allocation control signal through CSB#2 in the broadband.

Referring to FIG. 57 , after the first timer 5710 is started, during BW switching of the terminal, the base station signal is successfully received through the wideband CSB #2 5730, the timer expires, and the DL signal is not received in the subsequent subframe, so the second The operation of starting the timer 5720 is shown.

Referring to FIG. 58 , in order to avoid the complicated operation as shown in FIGS. 56 and 57 , the base station may set a pattern 5810 of switching between wideband and narrowband as RRC after wideband switching of the terminal. As in other embodiments, the first wideband switching may be indicated by the base station to the terminal with the L1 control signal 5820 or the RRC signal. In the case of RRC control, the location should be determined based on the SFN and the subframe. In various examples of the present disclosure, when BW switching is not urgent, the L1 control signal may be replaced with MAC CE (Command Elements). In this case, the MAC CE should include absolute location information instead of relative interval information.

The pattern of BW switching may be set to an absolute position with respect to the SFN and the subframe, or may be set to a relative position based on the position specified by the L1 control signal. In addition, the subframe in which the pattern is valid may be limited to a subframe corresponding to DRX on duration or a subframe before the DRX cycle timer expires. In addition, the base station may indicate to which BW the terminal will switch to with the MAC CE.

When the base station instructs the BW switching operation using the physical layer signal or the RRC control signal, for dynamic setting, the setting by the L1 control signal may take precedence over the setting by the RRC control signal. However, in consideration of a case in which stable terminal operation is difficult due to a large number of L1 control signals, in a subframe at a predetermined position (period, offset), the setting by the RRC control signal can always take precedence over the setting by the L1 control signal. .

Meanwhile, apart from the BW control operation by the physical layer signal, the C-DRX operation of LTE, that is, the Connected DRX operation, may be modified to be linked with the BW control. The method using C-DRX may operate alone or may be operated together with the operation of controlling the BW with a physical layer signal. Specific details will be described with reference to FIG. 59 .

59 to 60 are diagrams illustrating a C-DRX operation for adaptive BW according to an embodiment of the present disclosure.

According to the LTE DRX setting, one DRX cycle is divided into On and Off duration. Similarly, referring to FIG. 59 , the base station may set one DRX cycle by dividing it into a wideband On duration (5910), a narrowband On duration (5920), and an Off duration (5930). For this method, the base station may additionally classify only On duration information for each band in the DRX configuration information and inform the terminal. However, when the size of the band to be gradually reduced is varied, it may take a considerable amount of time for the UE to completely transition to the Off state.

Referring to FIG. 60 , according to another embodiment, the terminal may operate in a DRX cycle for each band in which a wideband and narrowband monitoring period may be set differently in time. This is similar to the operation of converting to a long DRX cycle when a certain number of cycles are required from a short DRX cycle in LTE C-DRX operation. Therefore, the base station sets each DRX cycle information (DRX cycle, on duration, DRX cycle timer, etc.) (6010 to 6060) according to the band to be switched, and the band switching rule may be included in the C-DRX configuration. For example, it may be expressed in the order of band #1, band #2, band #3, ..., or the order of CSB #1, CSB #2, CSB #3, ....

Alternatively, according to an embodiment, the order of band switching may be entirely entrusted to the physical layer. In this case, the UE operates with a common DRX cycle and DRX cycle timer, but BW and CSB are determined according to the L1 control signal. The UE may inquire about the BW to be changed to L1 before one DRX cycle timer expires.

Alternatively, in the process of RRC connection setup or RRC connection reestablishment, the UE may request the L1 to set a plurality of BWs (CSBs) and their order. When one DRX cycle timer expires or the DRX cycle ends, the UE switches the BW (CSB) in the set order. If the terminal re-extends the BW by the BW resetting control signal of the base station or by a condition preset to the terminal, the BW (CSB) is switched from the extended BW again in the set order. If the DRX cycle or DRX cycle timer for the minimum BW (CSB) expires after conversion is made for all the configured BWs (CSB), the UE a) converts to long DRX while maintaining the minimum BW (CSB), or b) separately Convert to long DRX by switching to the configured BW (CSB) for long DRX, or c) switch to Idle DRX; works as one of

Meanwhile, without introducing a new C-DRX configuration, the existing LTE C-DRX configuration and operation may be maintained as it is, and the BW change operation may be controlled with an additional L1 configuration. According to an embodiment, the C-DRX settings controlled by RRC are the same, but the base station may set information (BW, SRB, number of subframes, etc.) for BW switching within the On duration using the L1 signal. According to another embodiment, the base station may set information (BW, SRB, etc.) for BW conversion, which is reduced every time it undergoes one short DRX cycle using the L1 signal. According to another embodiment, the base station may set the BW connected to the short DRX cycle and the BW connected to the long DRX cycle using the L1 signal.

The transformation operation of the C-DRX assumes that there are different variables for each BW in one DRX configuration. On the other hand, you can set different DRX settings for each BW for more free DRX settings. In this case, the terminal should operate while simultaneously reviewing a plurality of DRX settings, and in order to prevent confusion of operations according to the plurality of DRX settings, which DRX setting has priority should be set according to a predetermined rule.

61 is a diagram illustrating an example of DRX configuration for each wideband and narrowband according to an embodiment of the present disclosure.

Referring to FIG. 61 , a state in which wideband DRXs 6110 and 6115 and narrowband DRXs 6120 and 6125 are configured is shown, respectively. The UE receives the DRX configuration for the two bands, and must follow one of the DRX configurations for a subframe in which a conflicting operation occurs. If power consumption is important, the terminal may prioritize narrowband DRX configuration over wideband DRX.

62 and 63 are diagrams illustrating examples of DRX settings and priority rules for each wideband and narrowband according to an embodiment of the present disclosure.

Referring to FIG. 62, when both the wideband On duration (6210) and the narrowband On duration (6220) are set in one subframe with respect to the setting of FIG. 61, the narrowband On duration setting (6210) is followed and the terminal is narrow The operation of monitoring the DL signal by setting the band CSB#1 is shown.

Referring to FIG. 63, on the other hand, if the amount of data transmission is more important, the wideband On duration (6310) and the narrowband On duration (6320) for the setting of FIG. 61 are all set in one subframe as in FIG. 63 In this case, it follows the setting of the wideband On duration (6310) and indicates an operation in which the terminal monitors the DL signal by switching to the wideband CSB#2. The base station may additionally set priority information between DRX for each band as RRC to the terminal in order to support other settings as shown in FIGS. 62 and 63 .

When a DL signal is not received in the DRX configuration and operation of the plurality of bands, the UE starts an inactivity timer. If the inactivity timer for each band is set, the UE starts a) when the DL signal corresponding to the band is not received, starts the inactivity timer for each band, or b) when the DL signal corresponding to the band is not received, all bands start a star inactivity timer; It can work with either one.

If the inactivity timer is set to a single value regardless of the band, the condition for determining DRX inactivity may be determined by at least one of the following: 1) Inactivity timer only when DL signals are not received in all bands (all configured CSBs) or 2) starts the inactivity timer only when a DL signal corresponding to the band (CSB) selected by priority is not received; It can work with either one.

In the present disclosure, the type of the DL signal to be monitored related to the DRX operation is determined in the standard or may be set by the base station. If a DL signal that is not a DRX operation-related monitoring target is received, it may be considered that the DL signal is not received in the DRX operation.

In the BW adaptation and power saving procedure proposed in the present disclosure, it is additionally necessary to configure one or more bands configured for scheduling in association with the DRX procedure.

According to various proposed embodiments, a setting method in connection with the DRX procedure may be different. Broadly, each embodiment is classified as follows, and the DRX procedure association setting may be different according to the classification.

A. When the timing when the terminal switches from band1 to band2 follows the L1/MAC signal of the base station, and the timing when switching from band2 to band1 also follows the L1/MAC signal of the base station:

Since the band ID is included in the L1/MAC signal, there is no connection with a separate DRX setting. That is, DRX operates in common regardless of a band. However, the base station may set a specific band (eg, band 1) for a fallback operation when a reception error of the L1/MAC signal of the base station occurs. In this case, the base station may configure the DRX configuration to include a fallback band.

B. The timing when the terminal switches from band 1 to band 2 follows the L1/MAC signal of the base station, and the timing when switching from band 2 to band 1 follows the Inactivity Timer:

When the UE switches from band 1 to band 2, there is no need to configure band 2 associated with DRX. However, when switching from band 2 to band 1, it follows the timer, so the base station sets DRX to operate in band 1. After switching to band 2, the terminal must follow the inactivity timer of band 2, 1) using the inactivity timer of DRX in common, 2) using the inactivity timer set separately for band 2, or 3) using the inactivity timer of DRX. Use the scaled value, or 4) use the scaled value of the Inactivity Timer set separately for band 1; may be configured by the base station to operate according to one of the The scale value can be indicated by the DRX setting or a separate setting.

C. The terminal switches from band 1 to band 2 according to the L1/MAC signal of the base station, but the control channel reception timing is set separately, and the switching from band 2 to band 1 also follows the L1/MAC signal of the base station, but the control channel reception timing is If set separately:

In this case, the DRX cycle and On duration must be set for each band or for each band. In the case of common band, there is no need for a separate band setting for DRX setting. When DRX is set for each band, 1) adjust the DRX setting to the number of bands and indicate a band in each DRX setting, or 2) DRX setting is set to one, and a band for On duration and Off duration operations included in the DRX setting 3) DRX setting is set to one, indicating the band for each short DRX cycle and long DRX cycle included in the DRX setting, or 4) DRX setting is set to one, and On duration, short DRX included in the DRX setting. indicate the band for each cycle, long DRX cycle; set by at least one or more of the following methods.

In the configuration and procedure proposed in the present disclosure, Layer 2 of the terminal may not need to know the actual location and band of the band. That is, the physical information of the band is not visible in Layer2, but the logical location and size can be set. Layer 2 may configure a control channel or a transport channel based on location/size information of a logical band. In addition, the UE may manage the BW information as a list for DRX operation operation and display it by dividing it with an index.

In the examples proposed in the present disclosure, it is assumed that most terminals cannot simultaneously monitor narrowband and wideband BW. However, depending on the capability of the terminal, in some cases, narrowband and wideband BW can be monitored at the same time.

On the other hand, the BW provided through the L1 signal and the maximum BW of the terminal according to the UE capability may be different. Therefore, when receiving a plurality of DRX configurations for each BW, within the maximum BW of UE capability, the UE may simultaneously operate in On duration of one or more BW-specific DRX configurations. On duration of DRX configuration exceeding the maximum BW of UE capability is excluded from monitoring. For this operation, the priority of DRX configuration for each BW may be set from the base station to the terminal.

64 is a flowchart illustrating an operation of a terminal according to an embodiment of the present disclosure.

Referring to FIG. 64 , the UE requests (S6420) and obtains (S6430) information on the location of the operating BW or control subband (CSB) from the physical layer during the RRC Connection Setup procedure (S6410).

Based on the obtained information on the position of the operating BW or control subband, or by reporting the information to the base station, the terminal receives the DRX configuration for each BW or the configuration for the variable for each BW in the DRX from the base station (S6440).

When the connection is completed, the terminal starts an operation for short DRX among C-DRX. The terminal performs PDCCH monitoring for receiving the control signal of the base station every subframe (S6450). Then, the terminal determines whether the reception of the DL signal is successful (S6460).

If the DL signal reception is successful, the UE continues to monitor the PDCCH. In certain scenarios, despite successful PDCCH monitoring, it is sometimes switched to monitoring other BW or CSB by L1 control or RRC control.

If the UE does not receive a DL signal as a result of monitoring the PDCCH, the UE updates DRX variables such as the inactivity timer and the DRX cycle timer (S6465). If the inactivity timer or BW conversion timer condition is satisfied and BW conversion is required (S6470), the UE checks whether the short DRX termination condition is met (S6475). This condition corresponds to, for example, when PDCCH monitoring fails at the minimum BW, there is no more BW to decrease, or the short DRX cycle timer expires.

If the short DRX termination condition is not satisfied (S6470), the terminal decreases the BW (S6480) and resumes the short DRX operation again.

If the Short DRX termination condition is satisfied, the UE starts long DRX (S6485). Long DRX operation operates at minimum or set BW, and general operation is the same as LTE long DRX. The UE monitors the PDCCH according to the long DRX (S6490), and if it does not succeed in receiving the DL signal (S6491), it determines whether the long DRX termination condition is satisfied (S6492). If the Long DRX termination condition is satisfied, the terminal is switched to the idle mode (S6493).

- How to separately set conditions that determine inactivity in wideBWP:

The difference in the BW adaptation or switching operation of the present disclosure from SCell addition/release in the existing CA is that the CA always monitors the PCell because the PCell is activated. The point is to transmit/receive major control signals such as signals and MAC CE. Therefore, even if one band (band 1) is switched to another band (band 2) and there is no data traffic in band 2, the UE can receive the RRC/MAC control signal of the base station. However, the reception of the RRC/MAC control signal of the base station in the broadband band 2 affects power consumption of the terminal. Therefore, when the terminal determines inactivity in band 2, 1) the control channel activity for transmitting only the RRC/MAC control signal of the base station is not reflected in the inactivity timer operation, or 2) the inactivity timer operates only for scheduling assignments below a certain PRB 3) When a base station signal is received less than a certain number of times (or transmission amount) within a certain section, it is reflected in the inactivity timer operation, 4) only for a specific DCI format, is reflected in the inactivity timer operation, or 5) by a separate instruction from the base station Decide whether or not to be reflected in the Inactivity Timer operation; may operate according to at least one of

- Dual timer setup:

Previously, the timer operation for switching from wideband to narrowband was mainly described. On the other hand, the transition from the narrowband to the wideband may be indicated by the DCI/MAC signal of the base station. However, even when an error occurs in DCI/MAC signal reception, the UE must switch from wideband to narrowband for fallback. However, since the corresponding requirements in the two cases may be different, the base station may set this timer value differently. That is, when the terminal receives a DCI/MAC signal for switching to a wideband while monitoring in a narrowband, timer #1 is started. In the operation of the terminal related to the timer #1, if the base station signal in the broadband is not received until the timer #1 expires while performing the band switching operation, the terminal returns to the narrowband.

On the other hand, after the terminal has already succeeded in receiving the base station signal in the broadband, the terminal that has not received the base station signal after the On duration period ends starts timer #2. When this timer #2 expires, the terminal switches to the narrowband. In general, taking the value of Timer #1 shorter than the value of Timer #2 has an advantage as it enables fast fallback for error situations.

65 illustrates a DRX operation for TTI change according to an embodiment of the present disclosure.

Referring to FIG. 65 , a Transmit Time Interval (TTI) means a time taken to transmit one or more Transport Blocks (TBs) and is often used as a basic time unit for performing scheduling and HARQ operations in a MAC. The terminal receives TTI information preset in an initial access procedure or default TTI and BW information through SI.

For example, a normal TTI of 1 ms length may be set as a basic TTI. In addition, the terminal may receive additional TTI and BW information set in an RRC message during the random access procedure or after completion of the RRC connection setup. For example, the additional TTI may be set to a Short TTI of 0.5 ms length.

All variables for expressing DRX operation in LTE are expressed in units of subframes. Looking at the Normal TTI case 6510 of FIG. 65 , it can be seen that the On duration is expressed as 2 ms and the DRX cycle is expressed as 6 ms.

If the same DRX variable expression method as that of LTE is brought to 5G as it is, since the TTI is set to short TTI as in Short TTI case A (6520), the UE monitors the PDCCH for 2 ms On duration within the same DRX cycle (6 ms). do. At this time, in the Normal TTI case, the number of PDCCH monitoring is 2 in the same On duration (2ms), whereas in the Short TTI case A, the number of PDCCH monitoring is increased to 4 because the TTI length is halved, but the same PDCCH monitoring opportunity is not maintained, so the power consumption of the terminal may increase.

In the case of Short TTI case B (6530), the number of PDCCH monitoring is reduced from 2 ms to 1 ms according to the TTI with reduced On duration, and the number of PDCCH monitoring is also reduced to 2 within one On duration. However, since the DRX cycle is also reduced from 6 ms to 3 ms according to the reduced TTI, 4 PDCCH monitoring times are still set for the same time as in the Normal TTI case. Therefore, the power consumption of the terminal is the same in the Short TTI case A (6520) and the Short TTI case B (6530).

Therefore, the present disclosure proposes the following method. That is, among the DRX variables, Timers (On duration, Inactivity Timer, etc.) related to PDCCH monitoring are expressed as TTI and other variables are expressed as subframes.

Referring to Short TTI case C (6540), the On duration is reduced from 2 ms to 1 ms compared to the Normal TTI, and the number of PDCCH monitoring is also maintained at 2 times in one On duration. Also, within the DRX cycle 6 ms, the number of PDCCH monitoring compared to Normal TTI is kept the same as 2 times. In detail, On duration, Inactivity Timer, ULRetransmissionTimer, StartOffset, etc. may be expressed as TTI, and DRX cycle, shortCycleTimer, etc. may be expressed as a subframe.

The TTI length may be configured as SI or RRC, but additional TTI or PDCCH resources may be configured in the physical layer (L1) for convenience of dynamic scheduling. However, if the TTI length is dynamically changed according to additional TTI / PDCCH resource configuration, a delay may occur in recalculating the Timer in the L2 layer. This delay may cause a problem when scheduling/HARQ operation occurs in short TTI. Therefore, the present disclosure proposes a method in which the TTI dynamically changed according to the L1 signal is not included in the MAC timer calculation. According to an embodiment, according to the present disclosure, a change within a specific time length set as RRC may not be included in the MAC timer calculation, and a change over a set specific time length may be included in the MAC timer calculation.

According to an embodiment, the base station may set to the terminal what length of TTI for a specific timer is defined based on the RRC message. For example, On duration may be set as shortest TTI (0.25 ms), Inactivity Timer as shorter TTI (0.5 ms), and DRX cycle as normal TTI (1.0 ms). Alternatively, some variables may have their relationship specified in the standard in advance. For example, On duration may be specified according to the length of the mini-slot set in L1, and the DRX cycle may be specified to conform to the length of the slot set in L1.

According to an embodiment, the base station may set some of the variables necessary for the DRX procedure to fix a time unit and to change other time units according to numerology. The base station fixes DRX cycle, shortCycleTimer, etc. in units of subframes, and On duration, Inactivity Timer, ULRetransmissionTimer, StartOffset, etc. are expressed in units of [slots, minislots], but the control channel, Band, and It may be determined according to a combination of at least one of Index in DCI and TTI. For example, when the terminal receives the control channel in Band 1 for eMBB, the On duration value 4 is understood as 4 slots, and when the terminal receives the control channel in Band 2 for URLLC, the same On duration value 4 is 4 minislots. It is understood.

66 is a diagram illustrating an example in which a TTI value is determined differently depending on a situation according to a control channel observation period and a transmission length according to an embodiment of the present disclosure.

Referring to FIG. 66 , the value of the TTI may be determined differently according to circumstances as shown in FIG. 66 according to a control channel monitoring periodicity and a transmission duration.

In (a) and (b) of FIG. 66, since data channels are allocated only within the control channel observation period, the scheduling transmission period is the same as the control channel observation period. Therefore, the TTI is equal to the control channel observation period. However, in (c) 6630 of FIG. 66 , since a transmission length longer than the control channel observation period is indicated, the scheduling transmission period is ambiguous.

This may vary according to the control of the base station. When the base station instructs the terminal to have a transport block with a transmission length longer than the control channel observation period, if the TTI is controlled not to observe the overlapping control channel, the TTI is the same as the indicated transmission length. However, if the base station instructs the terminal to observe the control channel observation period even during the transmission length, the base station may schedule the terminal for every control channel observation period. Therefore, in this case, the TTI is equal to the control channel observation period.

A detailed embodiment of the operation of switching bands based on a timer as shown in FIGS. 54, 55, 56, and 60 will be described below. This timer may be a new timer such as a band switching timer or a band validity timer, or an existing timer such as a drx inactivity timer or a drx short cycle timer.

67 is a diagram for explaining an operation of switching a band based on a timer according to an embodiment of the present disclosure.

[Example 4-1]

Referring to FIG. 67 , the 4-1 embodiment shows an operation procedure for supporting A 6710 .

The MAC entity may be configured to have a DRX function for controlling PDCCH monitoring of the UE by RRC. When DRX is configured in the RRC_CONNECTED state of the UE, the MAC entity may monitor the PDCCH non-continuously according to the described DRX operation. When using the DRX operation, the MAC entity must monitor the PDCCH using a specific band at a specific time according to specific requirements. At least one of the following variables is set for DRX operation: drx_BandIndex, onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimer, drx-ULRetransmissionTimer, longDRX-Cycle, drxStartOffset, drxShortCycleTimer, shortDRX-Cycle.

The drx_BandIndex related to the band may be included in the DRX configuration or may be determined as an index of a band configured as a default band or a primary band in the band configuration included in the RRC Connection (re-)Configuration procedure without being included in the DRX configuration.

For example, it may be indicated as drx_BandIndex = defaultBandIndex, or drx_BandIndex = primaryBandIndex.

When the DRX cycle is set, the MAC entity of the terminal operates in Active Time at the following time.

- When at least one of onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimer, drx-ULRetransmissionTimer, and mac-ContentionResolutionTimer is running,

- When SR (Scheduling Request) is sent to PUCCH and pending,

- When a UL grant for unsent HARQ retransmission may occur,

- When a control signal is generated for the first transmission in the PDCCH after RAR reception,

When DRX is configured, the MAC entity of the terminal performs the following in every subframe (or a time unit configured as a slot, symbol, or RRC).

- When DRX Command MAC CE or Long DRX Command MAC CE is received,

Stop onDurationTimer and drx-Inactivity Timer.

- When drx-Inactivity Timer expires or DRX Command MAC CE is received,

■ If short DRX cycle is set, (re)start drxShortCycleTimer and use short DRX cycle.

■ If short DRX cycle is not set, long DRX cycle is used.

- When drxShortCycleTimer expires, a long DRX cycle is used.

- If the drxShortCycleTimer has not expired and a Long DRX Command MAC CE is received,

Stop drxShortCycleTimer and use long DRX cycle.

- If the terminal is using a short DRX cycle and the following equation is satisfied according to the current SFN and subframe values, onDurationTimer is started.

■ [(SFN * 10) + subframe number] modulo (shortDRX-Cycle) = (drxStartOffset) modulo (shortDRX-Cycle);

- If the terminal is using a long DRX cycle and the following equation is satisfied according to the current SFN and subframe values, onDurationTimer is started.

■ [(SFN * 10) + subframe number] modulo (longDRX-Cycle) = drxStartOffset;

The MAC entity of the UE monitors the PDCCH in a subframe (or a time unit set to a slot, symbol, or RRC) in which the PDCCH is present in Active Time and in a band indicated by drx_BandIndex. If the PDCCH indicates DL transmission in this subframe or DL assignment is set in this subframe, the UE starts the HARQ RTT Timer for the corresponding HARQ process and stops the drx-RetransmissionTimer for the same HARQ process.

If the PDCCH indicates UL transmission in this subframe or a UL grant is set in this subframe, the UE starts the UL HARQ RTT Timer for the HARQ process of the subframe including the last retransmission of the corresponding PUSCH transmission. Also, stop drx_ULRetransmissionTimer for the same HARQ process.

If the PDCCH indicates a new transmission, the UE (re)starts drx-InactivityTimer.

[Example 4-2]

Embodiment 4-2 shows an operation procedure supporting B 6720 of FIG. 67 .

The MAC entity may be configured to have a DRX function for controlling PDCCH monitoring of the UE by RRC. When DRX is configured in the RRC_CONNECTED state of the UE, the MAC entity may monitor the PDCCH non-continuously according to the described DRX operation. When using the DRX operation, the MAC entity must monitor the PDCCH using a specific band at a specific time according to specific requirements. At least one of the following variables is set for DRX operation: onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimer, drx-ULRetransmissionTimer, longDRX-Cycle, drxStartOffset, drx_BandIndex_longDRX-Cycle, drxShortCycleTimer, shortDRX-CycleTimer.

The drx_BandIndex_longDRX-Cycle related to the band is included in the DRX configuration or is not included in the DRX configuration and is included in the RRC Connection (re-)Configuration procedure. .

For example, it may be indicated as drx_BandIndex_longDRX-Cycle = defaultBandIndex or drx_BandIndex_longDRX-Cycle = primaryBandIndex.

When the DRX cycle is set, the MAC entity of the terminal operates in Active Time at the following time.

- When at least one of onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimer, drx-ULRetransmissionTimer, and mac-ContentionResolutionTimer is running,

- When SR (Scheduling Request) is sent to PUCCH and pending,

- When a UL grant for unsent HARQ retransmission may occur,

- When a control signal is generated for the first transmission in the PDCCH after RAR reception,

When DRX is configured, the MAC entity of the terminal performs the following in every subframe (or a time unit configured as a slot, symbol, or RRC).

- When DRX Command MAC CE or Long DRX Command MAC CE is received,

Stop onDurationTimer and drx-Inactivity Timer.

- When drx-Inactivity Timer expires or DRX Command MAC CE is received,

■ If short DRX cycle is set, (re)start drxShortCycleTimer and use short DRX cycle.

■ If short DRX cycle is not set, long DRX cycle is used.

- When drxShortCycleTimer expires, a long DRX cycle is used.

- If the drxShortCycleTimer has not expired and a Long DRX Command MAC CE is received,

Stop drxShortCycleTimer and use long DRX cycle.

- If the terminal is using a short DRX cycle and the following equation is satisfied according to the current SFN and subframe values, onDurationTimer is started.

■ [(SFN * 10) + subframe number] modulo (shortDRX-Cycle) = (drxStartOffset) modulo (shortDRX-Cycle);

- If the terminal is using a long DRX cycle and the following equation is satisfied according to the current SFN and subframe values, onDurationTimer is started.

■ [(SFN * 10) + subframe number] modulo (longDRX-Cycle) = drxStartOffset;

The MAC entity of the UE monitors the PDCCH in a subframe (or a time unit set by slot, symbol, or RRC) with PDCCH in Active Time, and in a band indicated by drx_BandIndex_longDRX-Cycle when Long DRX Cycle is used. If the PDCCH indicates DL transmission in this subframe or DL assignment is set in this subframe, the corresponding terminal starts the HARQ RTT Timer for the HARQ process and stops the drx-RetransmissionTimer for the same HARQ process.

If the PDCCH indicates UL transmission in this subframe or a UL grant is set in this subframe, the UE starts the UL HARQ RTT Timer for the HARQ process of the subframe including the last retransmission of the corresponding PUSCH transmission. Also, stop drx_ULRetransmissionTimer for the same HARQ process.

If the PDCCH indicates a new transmission, the UE (re)starts drx-InactivityTimer.

[Example 4-3]

Embodiment 4-3 shows an operation procedure supporting both A 6710 and B 6720 of FIG. 67 .

The MAC entity may be configured to have a DRX function for controlling PDCCH monitoring of the UE by RRC. When DRX is configured in the RRC_CONNECTED state of the UE, the MAC entity may monitor the PDCCH non-continuously according to the described DRX operation. When using the DRX operation, the MAC entity must monitor the PDCCH using a specific band at a specific time according to specific requirements. At least one of the following variables is set for the DRX operation: onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimer, drx-ULRetransmissionTimer, longDRX-Cycle, drxStartOffset, drx_BandIndex_longDRX-Cycle, drxShortDRX-Cycle, short drx_BandCycleTimer, drx_BandCycleTimer.

The drx_BandIndex_longDRX-Cycle or drx_BandIndex_shortDRX-Cycle related to the band is included in the DRX configuration or not included in the DRX configuration and is an index of a band set as the default band or primary band in the band configuration included in the RRC Connection (re-)Configuration procedure. can be determined

For example, it may be indicated as drx_BandIndex_shortDRX-Cycle = defaultBandIndex or drx_BandIndex_longDRX-Cycle = primaryBandIndex.

When the DRX cycle is set, the MAC entity of the terminal operates in Active Time at the following time.

- When at least one of onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimer, drx-ULRetransmissionTimer, and mac-ContentionResolutionTimer is running,

- When SR (Scheduling Request) is sent to PUCCH and pending,

- When a UL grant for unsent HARQ retransmission may occur,

- When a control signal is generated for the first transmission in the PDCCH after RAR reception,

When DRX is configured, the MAC entity of the terminal performs the following in every subframe (or a time unit configured as a slot, symbol, or RRC).

- When DRX Command MAC CE or Long DRX Command MAC CE is received,

Stop onDurationTimer and drx-Inactivity Timer.

- When drx-Inactivity Timer expires or DRX Command MAC CE is received,

■ If short DRX cycle is set, (re)start drxShortCycleTimer and use short DRX cycle.

■ If short DRX cycle is not set, long DRX cycle is used.

- When drxShortCycleTimer expires, a long DRX cycle is used.

- If the drxShortCycleTimer has not expired and a Long DRX Command MAC CE is received,

Stop drxShortCycleTimer and use long DRX cycle.

- If the terminal is using a short DRX cycle and the following equation is satisfied according to the current SFN and subframe values, onDurationTimer is started.

■ [(SFN * 10) + subframe number] modulo (shortDRX-Cycle) = (drxStartOffset) modulo (shortDRX-Cycle);

- If the terminal is using a long DRX cycle and the following equation is satisfied according to the current SFN and subframe values, onDurationTimer is started.

■ [(SFN * 10) + subframe number] modulo (longDRX-Cycle) = drxStartOffset;

The MAC entity of the UE is in the subframe (or slot, symbol, or time unit set to RRC) with PDCCH in Active Time, and in the band indicated by drx_BandIndex_shortDRX-Cycle when using Short DRX Cycle, or when using Long DRX Cycle In the band indicated by drx_BandIndex_longDRX-Cycle, the PDCCH is monitored. If the PDCCH indicates DL transmission in this subframe or DL assignment is set in this subframe, the UE starts the HARQ RTT Timer for the corresponding HARQ process and stops the drx-RetransmissionTimer for the same HARQ process.

If the PDCCH indicates UL transmission in this subframe or a UL grant is set in this subframe, the UE starts the UL HARQ RTT Timer for the HARQ process of the subframe including the last retransmission of the corresponding PUSCH transmission. Also, stop drx_ULRetransmissionTimer for the same HARQ process.

If the PDCCH indicates a new transmission, the UE (re)starts drx-InactivityTimer.

[Example 4-4]

Embodiment 4-4 shows an operation procedure supporting B 6720 of FIG. 67 .

The MAC entity may be configured to have a DRX function for controlling PDCCH monitoring of the UE by RRC. When DRX is configured in the RRC_CONNECTED state of the UE, the MAC entity may monitor the PDCCH non-continuously according to the described DRX operation. When using the DRX operation, the MAC entity must monitor the PDCCH using a specific band at a specific time according to specific requirements. At least one of the following variables is set for DRX operation: onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimer, drx-ULRetransmissionTimer, longDRX-Cycle, drxStartOffset, drx_BandIndex_longDRX-Cycle, drxShortCycleTimer, shortDRX-CycleTimer.

The drx_BandIndex_longDRX-Cycle related to the band is included in the DRX configuration or is not included in the DRX configuration and is included in the RRC Connection (re-)Configuration procedure. .

For example, it may be indicated as drx_BandIndex_longDRX-Cycle = defaultBandIndex or drx_BandIndex_longDRX-Cycle = primaryBandIndex.

When the DRX cycle is set, the MAC entity of the terminal operates in Active Time at the following time.

- When at least one of onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimer, drx-ULRetransmissionTimer, and mac-ContentionResolutionTimer is running,

- When SR (Scheduling Request) is sent to PUCCH and pending,

- When a UL grant for unsent HARQ retransmission may occur,

- When a control signal is generated for the first transmission in the PDCCH after RAR reception,

When DRX is configured, the MAC entity of the terminal performs the following in every subframe (or a time unit configured as a slot, symbol, or RRC).

- When DRX Command MAC CE or Long DRX Command MAC CE is received,

Stop onDurationTimer and drx-Inactivity Timer.

- When drx-Inactivity Timer expires or DRX Command MAC CE is received,

■ If short DRX cycle is set, (re)start drxShortCycleTimer and use short DRX cycle.

■ If short DRX cycle is not set, long DRX cycle is used and the band indicated by drx_BandIndex_longDRX-Cycle is used.

- When drxShortCycleTimer expires, long DRX cycle is used and the band indicated by drx_BandIndex_longDRX-Cycle is used.

- If the drxShortCycleTimer has not expired and a Long DRX Command MAC CE is received,

Stop drxShortCycleTimer, use long DRX cycle, and use the band indicated by drx_BandIndex_longDRX-Cycle.

- If the terminal is using a short DRX cycle and the following equation is satisfied according to the current SFN and subframe values, onDurationTimer is started.

■ [(SFN * 10) + subframe number] modulo (shortDRX-Cycle) = (drxStartOffset) modulo (shortDRX-Cycle);

- If the terminal is using a long DRX cycle and the following equation is satisfied according to the current SFN and subframe values, onDurationTimer is started.

■ [(SFN * 10) + subframe number] modulo (longDRX-Cycle) = drxStartOffset;

The MAC entity of the UE monitors the PDCCH in a subframe (or a time unit configured as a slot, symbol, or RRC) in which the PDCCH is present in Active Time. If the PDCCH indicates DL transmission in this subframe or DL assignment is set in this subframe, the UE starts the HARQ RTT Timer for the corresponding HARQ process and stops the drx-RetransmissionTimer for the same HARQ process.

If the PDCCH indicates UL transmission in this subframe or a UL grant is set in this subframe, the UE starts the UL HARQ RTT Timer for the HARQ process of the subframe including the last retransmission of the corresponding PUSCH transmission. Also, stop drx_ULRetransmissionTimer for the same HARQ process.

If the PDCCH indicates a new transmission, the UE (re)starts drx-InactivityTimer.

[Example 4-5]

Embodiment 4-5 shows an operation procedure supporting both A 6710 and B 6720 of FIG. 67 .

The MAC entity may be configured to have a DRX function for controlling PDCCH monitoring of the UE by RRC. When DRX is configured in the RRC_CONNECTED state of the UE, the MAC entity may monitor the PDCCH non-continuously according to the described DRX operation. When using the DRX operation, the MAC entity must monitor the PDCCH using a specific band at a specific time according to specific requirements. At least one of the following variables is set for the DRX operation: onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimer, drx-ULRetransmissionTimer, longDRX-Cycle, drxStartOffset, drx_BandIndex_longDRX-Cycle, drxShortDRX-Cycle, short drx_BandCycleTimer, drx_BandCycleTimer.

The drx_BandIndex_longDRX-Cycle or drx_BandIndex_shortDRX-Cycle related to the band is included in the DRX setting or not included in the DRX setting and is an index of a band set as the default band or primary band in the band setting included in the RRC Connection (re-)Configuration procedure. can be determined For example, it may be indicated as drx_BandIndex_shortDRX-Cycle = defaultBandIndex or drx_BandIndex_longDRX-Cycle = primaryBandIndex.

When the DRX cycle is set, the MAC entity of the terminal operates in Active Time at the following time.

- When at least one of onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimer, drx-ULRetransmissionTimer, and mac-ContentionResolutionTimer is running,

- When SR (Scheduling Request) is sent to PUCCH and pending,

- When a UL grant for unsent HARQ retransmission may occur,

- When a control signal is generated for the first transmission in the PDCCH after RAR reception,

When DRX is configured, the MAC entity of the terminal performs the following in every subframe (or a time unit configured as a slot, symbol, or RRC).

- When DRX Command MAC CE or Long DRX Command MAC CE is received,

Stop onDurationTimer and drx-Inactivity Timer.

- When drx-Inactivity Timer expires or DRX Command MAC CE is received,

■ If short DRX cycle is set, (re)start drxShortCycleTimer, use short DRX cycle, and use the band indicated by drx_BandIndex_shortDRX-Cycle.

■ If short DRX cycle is not set, long DRX cycle is used and the band indicated by drx_BandIndex_longDRX-Cycle is used.

- When drxShortCycleTimer expires, long DRX cycle is used and the band indicated by drx_BandIndex_longDRX-Cycle is used.

- If the drxShortCycleTimer has not expired and a Long DRX Command MAC CE is received,

Stop drxShortCycleTimer, use long DRX cycle, and use the band indicated by drx_BandIndex_longDRX-Cycle.

- If the terminal is using a short DRX cycle and the following equation is satisfied according to the current SFN and subframe values, onDurationTimer is started.

■ [(SFN * 10) + subframe number] modulo (shortDRX-Cycle) = (drxStartOffset) modulo (shortDRX-Cycle);

- If the terminal is using a long DRX cycle and the following equation is satisfied according to the current SFN and subframe values, onDurationTimer is started.

■ [(SFN * 10) + subframe number] modulo (longDRX-Cycle) = drxStartOffset;

The MAC entity of the UE monitors the PDCCH in a subframe (or a time unit configured as a slot, symbol, or RRC) in which the PDCCH is present in Active Time. If the PDCCH indicates DL transmission in this subframe or DL assignment is set in this subframe, the UE starts the HARQ RTT Timer for the corresponding HARQ process and stops the drx-RetransmissionTimer for the same HARQ process.

If the PDCCH indicates UL transmission in this subframe or a UL grant is set in this subframe, the UE starts the UL HARQ RTT Timer for the HARQ process of the subframe including the last retransmission of the corresponding PUSCH transmission. Also, stop drx_ULRetransmissionTimer for the same HARQ process.

If the PDCCH indicates a new transmission, the UE (re)starts drx-InactivityTimer.

[Example 4-6]

Embodiment 4-6 shows an operation procedure supporting C 6730 of FIG. 67 .

The MAC entity may be configured to have a DRX function for controlling PDCCH monitoring of the UE by RRC. When DRX is configured in the RRC_CONNECTED state of the UE, the MAC entity may monitor the PDCCH non-continuously according to the described DRX operation. When using the DRX operation, the MAC entity must monitor the PDCCH using a specific band at a specific time according to specific requirements. At least one of the following variables is set for DRX operation: drx_BandIndex, onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimer, drx-ULRetransmissionTimer, longDRX-Cycle, drxStartOffset, drxShortCycleTimer, shortDRX-Cycle.

The drx_BandIndex related to the band may be included in the DRX configuration or may be determined as an index of a band configured as a default band or a primary band in the band configuration included in the RRC Connection (re-)Configuration procedure without being included in the DRX configuration.

For example, it may be indicated as drx_BandIndex = defaultBandIndex, or drx_BandIndex = primaryBandIndex.

When the DRX cycle is set, the MAC entity of the terminal operates in Active Time at the following time.

- When at least one of onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimer, drx-ULRetransmissionTimer, and mac-ContentionResolutionTimer is running,

- When SR (Scheduling Request) is sent to PUCCH and pending,

- When a UL grant for unsent HARQ retransmission may occur,

- When a control signal is generated for the first transmission in the PDCCH after RAR reception,

When DRX is configured, the MAC entity of the terminal performs the following in every subframe (or a time unit configured as a slot, symbol, or RRC).

- When DRX Command MAC CE or Long DRX Command MAC CE is received,

Stop onDurationTimer and drx-Inactivity Timer.

- If the current active band is not the same as the band indicated by drx_BandIndex;

■ When drx-Inactivity Timer expires,

◆ Use the band indicated by drx_BandIndex.

◆ (re)start drx-InactivityTimer.

- If the current active band is the same as the band indicated by drx_BandIndex;

■ When drx-Inactivity Timer expires or DRX Command MAC CE is received,

◆ If short DRX cycle is set, (re)start drxShortCycleTimer and use short DRX cycle.

◆ If short DRX cycle is not set, long DRX cycle is used.

■ When drxShortCycleTimer expires, a long DRX cycle is used.

■ If drxShortCycleTimer has not expired and a Long DRX Command MAC CE is received,

Stop drxShortCycleTimer and use long DRX cycle.

■ If the terminal is using a short DRX cycle and the following equation is satisfied according to the current SFN and subframe values, onDurationTimer starts.

◆ [(SFN * 10) + subframe number] modulo (shortDRX-Cycle) = (drxStartOffset) modulo (shortDRX-Cycle);

■ If the terminal is using a long DRX cycle and the following equation is satisfied according to the current SFN and subframe values, onDurationTimer is started.

◆ [(SFN * 10) + subframe number] modulo (longDRX-Cycle) = drxStartOffset;

The MAC entity of the UE monitors the PDCCH in a subframe (or a time unit configured as a slot, symbol, or RRC) in which the PDCCH is present in Active Time. If the PDCCH indicates DL transmission in this subframe or DL assignment is set in this subframe, the UE starts the HARQ RTT Timer for the corresponding HARQ process and stops the drx-RetransmissionTimer for the same HARQ process.

If the PDCCH indicates UL transmission in this subframe or a UL grant is set in this subframe, the UE starts the UL HARQ RTT Timer for the HARQ process of the subframe including the last retransmission of the corresponding PUSCH transmission. Also, stop drx_ULRetransmissionTimer for the same HARQ process.

The UE (re)starts drx-InactivityTimer when the PDCCH indicates new transmission.

In the timer-based switching operation between bands of the present disclosure, a band to be moved due to timer expiration may be determined according to one of the following methods.

1) When switching from band1 to band2, return to band1 due to timer expiration

2) Set the switch band for each timer

3) Return to previous band due to timer expiration

4) Return to the preset priority band due to timer expiration

An inter-band timer-based switching operation of the present disclosure is as follows.

68 is a diagram illustrating a timer-based band switch operation according to an embodiment of the present disclosure.

Referring to FIG. 68, if a condition given in advance or set by the base station is satisfied, the terminal operates a timer for one band (S6810). Some of the operation characteristics of the timer, for example, timer increase/decrease time, timer increase/decrease value, and timer expiration value, may be given in advance or set by the base station.

Depending on whether the condition is satisfied, the UE may start a timer or increase or decrease the timer value. When the current value of the timer reaches the timer expiration value, the terminal switches to another band (second band) from the operating band (first band) (S6820). Also, the timer operation for the first band is stopped.

The second band, which is a band to be switched, may be given in advance or may be set by the base station.

69 is another diagram illustrating a switching operation between bands based on a timer according to an embodiment of the present disclosure.

Referring to FIG. 69, upon receiving a scheduling indication for the first band from the base station (S6910), the terminal starts a timer for the first band (S6920). The timer increases or decreases by a certain amount over time according to a preset rule.

Then, the terminal determines whether the timer expires (S6930). When the timer for the first band is received again even though the timer has not expired, the terminal restarts the timer for the first band.

When the timer value reaches a given timer expiration value, the terminal switches from the first band to the second band (S6940). Also, the terminal stops the timer operation for the first band.

70 is another diagram illustrating an inter-band switching operation based on a timer according to an embodiment of the present disclosure.

Referring to FIG. 70, when the terminal receives a switching indication from the base station to switch from the currently operating band to the first band (S7010), the terminal starts a timer for the first band. The timer increases or decreases by a certain amount over time according to a preset rule.

Then, the terminal determines whether the timer expires (S7030). When the scheduling instruction for the first band is received again even though the timer has not expired, the terminal restarts the timer for the first band.

When the timer value reaches a given timer expiration value, the terminal switches from the first band to the second band (S7040). Also, the terminal stops the timer operation for the first band.

71 is another diagram illustrating an inter-band switching operation based on a timer according to an embodiment of the present disclosure.

Referring to FIG. 71, when the terminal receives a switching indication to switch to the first band from the base station (S7110), the terminal starts a timer for the first band (S7120).

Subsequently, if the terminal operating in the first band does not receive the scheduling instruction for the first band at a given time point, a timer for the first band is performed (S7140) and the timer value is increased or decreased by a certain amount according to a preset rule do.

If a scheduling instruction for the first band is received even though the timer for the first band has not expired, the terminal restarts the timer for the first band. When the timer value reaches a given timer expiration value (S7150), the terminal switches from the first band to the second band (S7160). Also, the terminal stops the timer operation for the first band.

72 is a diagram illustrating a configuration of a terminal device according to an embodiment of the present disclosure.

Referring to FIG. 72 , the terminal may include a transceiver 7210 for performing signal transmission/reception with another terminal, and a control unit 8220 for controlling all operations of the terminal device. In the present invention, the controller may be defined as a circuit or an application specific integrated circuit or at least one processor.

It can be understood that all operations for BW control, DRX control, and system time provision described above in the present invention and operations of the terminal according to the first to first embodiments of the present invention are performed by the controller 7220 . For example, the controller 7220 may control the signal flow between blocks to perform the operations according to the first to fourth embodiments described above. However, the controller 7220 and the transceiver 7110 does not necessarily have to be implemented as a separate device, and may be implemented as a single component in the form of a single chip.

73 is a diagram illustrating the configuration of a base station according to an embodiment of the present invention.

Referring to FIG. 73 , the base station may include a transceiver 7310 , a controller 7320 , and a memory 7330 (ie, a storage device). In the present invention, the controller may be defined as a circuit or an application specific integrated circuit or at least one processor.

The transceiver 7310 may transmit/receive a signal. The controller 7320 may control the overall operation of the base station according to the first to fourth embodiments proposed in the present invention. For example, the controller 7320 may control the signal flow between blocks to perform the operations according to the first to fourth embodiments described above.

It should be noted that the configuration diagram of the terminal, the example diagram of the control/data signal transmission method, the operation procedure example of the terminal, and the configuration diagram of the terminal device exemplified in FIGS. 1 to 73 are not intended to limit the scope of the present disclosure. shall. That is, all components, entities, or steps of operation described in FIGS. 3A to 3R should not be construed as essential components for implementation of the disclosure, and even including only some components, the scope does not impair the essence of the disclosure. can be implemented in

The operations of the base station or the terminal described above can be realized by providing a memory device storing the corresponding program code in an arbitrary component in the base station or the terminal device. That is, the control unit of the base station or the terminal device may execute the above-described operations by reading and executing the program code stored in the memory device by a processor or a central processing unit (CPU).

The various components and modules of the entity, base station or terminal device described in this specification include a hardware circuit, for example, a complementary metal oxide semiconductor-based logic circuit, and firmware. and software and/or hardware circuitry, such as a combination of hardware and firmware and/or software embedded in a machine-readable medium. For example, various electrical structures and methods may be implemented using electrical circuits such as transistors, logic gates, and application-specific semiconductors.

On the other hand, in the drawings for explaining the method of the present invention, the order of description does not necessarily correspond to the order of execution, and the precedence relationship may be changed or may be executed in parallel.

In addition, the drawings for explaining the method of the present invention may omit some components and include only some components within a range that does not impair the essence of the present invention.

In addition, embodiments of the present invention may be implemented in combination within a range that does not impair the essence of the present invention, or some components may be combined and implemented.

Meanwhile, although specific embodiments have been described in the detailed description of the present disclosure, various modifications are possible without departing from the scope of the present disclosure. Therefore, the scope of the present disclosure should not be limited to the described embodiments and should be defined by the claims described below as well as the claims and equivalents.

Claims (15)

A method performed by a terminal in a wireless communication system, the method comprising:
Receiving configuration information including information on the first band from the base station;
receiving, from the base station, control information for band switching;
performing band switching to a second band indicated by the control information within a section determined based on information on switching delay time;
starting a timer to go back from the second band to the first band; and
and performing band switching to the first band when the timer expires. According to claim 1,
The setting information comprises information on the interval of the timer. 3. The method of claim 2,
after performing band switching to the second band, receiving data from the base station in the second band. 3. The method of claim 2,
and restarting the timer when the control information is received again before the timer expires. A method performed by a base station in a wireless communication system, comprising:
transmitting configuration information including information on the first band to the terminal;
transmitting control information for band switching to the terminal;
transmitting data to the terminal through a second band indicated by the control information, a timer associated with the second band is started for the terminal to return to the first band from the second band; and
Transmitting data to the terminal through the first band based on the expiration of the timer,
The band switching to the second band is performed within a section determined based on information on the switching delay time. 6. The method of claim 5,
The setting information comprises information on the interval of the timer. 7. The method of claim 6,
After band switching to the second band is performed, the method further comprising the step of transmitting data to the terminal through the second band. 7. The method of claim 6,
If the control information is transmitted again before the timer expires, the timer is restarted. In a terminal of a wireless communication system,
transceiver; and
connected to the transceiver,
Receive configuration information including information on the first band from the base station,
Receive control information for band switching from the base station,
performing a band switch to the second band indicated by the control information within a section determined based on the information on the switch delay time;
starting a timer for returning from the second band to the first band;
and a controller for performing band switching to the first band when the timer expires. 10. The method of claim 9,
The configuration information terminal, characterized in that it includes information about the interval of the timer. 11. The method of claim 10,
The control unit is
After performing the band switch to the second band, the terminal, characterized in that for receiving data from the base station in the second band. 11. The method of claim 10,
When the control information is received again before the timer expires, the terminal is restarted. In a base station of a wireless communication system,
transceiver; and
connected to the transceiver,
Transmitting configuration information including information about the first band to the terminal,
Transmitting control information for band switching to the terminal,
a timer associated with the second band is started for transmitting data to the terminal through the second band indicated by the control information, and for the terminal to return to the first band from the second band; and
A control unit for transmitting data to the terminal through the first band based on the expiration of the timer,
The base station, characterized in that the band switching to the second band is performed within a section determined based on information on the switching delay time. 14. The method of claim 13,
The setting information is a base station, characterized in that it includes information about the interval of the timer. 15. The method of claim 14,
The control unit is
After band switching to the second band is performed, data is transmitted to the terminal through the second band,
If the control information is transmitted again before the timer expires, the timer is restarted.

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