CN110192415B

CN110192415B - Method, apparatus and system for terminal identification and paging signal transmission for terminal in power saving state

Info

Publication number: CN110192415B
Application number: CN201880006105.4A
Authority: CN
Inventors: 郑柄薰; A.阿吉瓦尔; 郑丁寿; 孙革敏; 柳善姬; 文廷敃; 朴承勋
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2017-01-05
Filing date: 2018-01-05
Publication date: 2022-11-18
Anticipated expiration: 2038-01-05
Also published as: KR20190095341A; CN110192415A; EP3549375A1; KR102408713B1; KR20180080966A; EP3549375A4

Abstract

The present disclosure relates to communication methods and systems for utilizing internet of things (IoT) technology to fuse fifth generation (5G) communication systems to support higher data rates than fourth generation (4G) systems. The present disclosure can be applied to intelligent services based on 5G communication technology and internet of things related technology, such as smart homes, smart buildings, smart cities, smart cars, networked cars, healthcare, digital education, smart retail, security, and security services. The present invention relates to a method of operating a terminal in a power saving state, a method for identifying a terminal and transmitting a paging signal to the terminal at a base station, and a system comprising such a terminal and such a base station.

Description

Method, apparatus and system for terminal identification and paging signal transmission for terminal in power saving state

Technical Field

The present disclosure relates to a next generation wireless communication system, and more particularly, to an operation method of a terminal in a power saving state, a method for identifying (identity) the terminal at a base station and transmitting a paging signal to the terminal, and a system including such a terminal and such a base station.

Background

Wireless data traffic has increased since the deployment of 4G communication systems. In order to meet this increased demand for traffic, efforts have been made to develop improved 5 th generation (5G) or first 5G communication systems. Accordingly, the 5G or first 5G communication system is also referred to as a "super 4G network" or a "Long Term Evolution (LTE) system". The 5G communication system is implemented in a higher frequency band (e.g., 60GHz band) in order to achieve a higher data rate. In order to reduce propagation loss of radio waves and increase transmission distance, beamforming, massive Multiple Input Multiple Output (MIMO), full-dimensional MIMO (FD-MIMO), array antenna, analog beamforming, and massive antenna techniques are discussed in the 5G communication system. In addition, in the 5G communication system, deployment of improvement for a system network is being made based on: advanced small cells, cloud Radio Access Networks (RANs), ultra-dense networks, device-to-device (D2D) communications, wireless backhaul, mobile networks, cooperative communications, coordinated multipoint (CoMP), and receive end interference cancellation, among others. In the 5G system, there have been developed: hybrid Frequency Shift Keying (FSK), quadrature Amplitude Modulation (QAM), sliding Window Superposition Coding (SWSC) as Advanced Coding Modulation (ACM); filterbank multi-carrier (FBMC), non-orthogonal multiple access (NOMA), and Sparse Code Multiple Access (SCMA) as advanced access technologies.

The internet is now evolving towards the internet of things (IoT), where distributed entities exchange and process information without human intervention. Internet of everything (IoE) has emerged as a combination of IoT technology and big data processing technology through connection with cloud servers. Because technical elements such as "sensing technology", "wired/wireless communication and network infrastructure", "service interface technology", and "security technology" are required for IoT implementations, sensor networks, machine-to-machine (M2M) communication, and Machine Type Communication (MTC) have recently been studied. Such IoT environments may provide intelligent Internet Technology (IT) services that create new value for human life by collecting and analyzing data generated between networked objects. Through the convergence and combination of existing Information Technology (IT) and various industrial applications, ioT can be applied to various fields, including: smart homes, smart buildings, smart cities, smart cars or networked cars, smart grids, healthcare, smart homes and advanced medical services.

In line with this, various attempts have been made to apply the 5G communication system to the IoT network. For example, technologies such as sensor networks, MTC, and M2M communication may be implemented through beamforming, MIMO, and array antennas. The application of a cloud Radio Access Network (RAN), which is a big data processing technology as described above, may also be considered as an example of the convergence between 5G technology and IoT technology.

Compared with the existing 4G system, the 5G system supports various services. For example, representative services are enhanced mobile broadband (eMBB) service, ultra-reliable and low latency communication (URLLC) service, large-scale machine type communication (mtc) service, and evolved multimedia broadcast/multicast service (eMBMS). A system providing an eMBB service may be referred to as an eMBB system. Similarly, a system providing URLLC service may be referred to as URLLC system, and a system providing mtc service may be referred to as mtc system. In addition, the terms "service" and "system" may be used interchangeably.

Disclosure of Invention

Technical problem

The present disclosure has been made to solve at least the above problems and/or disadvantages and to provide at least the advantages described below.

Accordingly, aspects of the present disclosure provide: methods of operating a terminal in a power saving state, methods for identifying a terminal at a base station and transmitting a paging signal to the terminal, and systems including such a terminal and such a base station.

Technical scheme

According to an aspect of the present disclosure, a method of operating a base station in a wireless communication system includes: receiving beam measurement information from a terminal; determining a base station transmission beam change for the terminal based on the beam measurement information; and changing the base station transmission beam based on a relationship between the new base station transmission beam included in the beam measurement information and the current reception beam of the terminal.

According to an aspect of the disclosure, a base station includes: a transceiver configured to transmit and receive a signal; and a controller configured to control: receiving beam measurement information from a terminal, determining a base station transmission beam change for the terminal based on the beam measurement information, and changing a base station transmission beam based on a relationship between a new base station transmission beam included in the beam measurement information and a current reception beam of the terminal.

According to an aspect of the present disclosure, a method of operating a terminal in a wireless communication system includes: performing beam measurements for at least one base station transmit beam and at least one terminal beam; transmitting beam measurement information to the base station based on the beam measurements; and receiving downlink information through a new base station transmission beam, wherein the new base station transmission beam is changed based on a relationship between the new base station transmission beam included in the beam measurement information and a current reception beam of the terminal.

According to an aspect of the present disclosure, a terminal includes: a transceiver configured to transmit and receive a signal; and a controller configured to control: the method includes performing beam measurements for at least one base station transmission beam and at least one terminal beam, transmitting beam measurement information to the base station based on the beam measurements, and receiving downlink information through a new base station transmission beam, wherein the new base station transmission beam changes based on a relationship between the new base station transmission beam included in the beam measurement information and a current reception beam of the terminal.

Advantageous effects of the invention

Accordingly, an aspect of the present disclosure provides a system, method and apparatus for performing beam tracking and feedback operations in a beamforming-based system.

Another aspect of the present invention provides a system, method and apparatus for performing beam tracking and feedback operations in a beamforming-based system.

Another aspect of the present invention provides a beam feedback and management method in a wireless communication system having a base station and a terminal both using multiple antennas.

Another aspect of the present invention provides a beam feedback and tracking method in a system and environment using beamforming based on multiple antennas, by which a terminal informs a base station of beam measurement information through an indicator.

Another aspect of the present disclosure provides a beam feedback and management method in a wireless communication system having a base station and a terminal both using multiple antennas.

Another aspect of the present disclosure provides a system including at least one base station and at least one terminal, wherein the terminal operates in a power saving state, and the base station identifies and recognizes an individual terminal and transmits a paging signal to the terminal.

Drawings

The above and other aspects, features and advantages of the present disclosure will become more apparent from the following description taken in conjunction with the accompanying drawings in which:

fig. 1A illustrates a RAN paging procedure in accordance with an embodiment of the present disclosure;

fig. 1B illustrates a paging receiving method of a terminal operating in a power saving state according to an embodiment of the present disclosure;

fig. 1C illustrates a method for using a new Radio Network Temporary Identifier (RNTI) for RAN paging in accordance with an embodiment of the present disclosure;

figure 1D illustrates various methods for constructing a RAN paging-temporary mobile subscription identity (RP-TMSI) (or new TMSI) in accordance with embodiments of the present disclosure;

fig. 1E illustrates RAN and Core Network (CN) paging procedures when adding an RP-TMSI and the operation of the corresponding terminal according to an embodiment of the present disclosure;

FIG. 1F illustrates a method of using both RP-RNTI and RP-TMSI in accordance with an embodiment of the disclosure;

fig. 1G illustrates a method of a last serving base station simplifying paging by using a cell-radio network temporary identifier (C-RNTI), according to an embodiment of the present disclosure;

FIG. 1HA and FIG. 1HB illustrate a method of a last serving base station transmitting a C-RNTI included in a paging message according to an embodiment of the present disclosure;

fig. 1I illustrates an environment where CN paging and RAN paging coexist with different periods and paging occasions according to an embodiment of the present disclosure;

fig. 1J illustrates an environment where CN paging and RAN paging coexist with the same periodicity and paging occasions according to an embodiment of the disclosure;

fig. 1K illustrates minimum/additional System Information (SI) modification period operation, in accordance with an embodiment of the present disclosure;

FIG. 1L illustrates a System Information Update (SIU) update operation according to an embodiment of the present disclosure;

fig. 1M illustrates uplink transmission (transmission) resource allocation in a paging Physical Downlink Control Channel (PDCCH) for fast reconnection according to an embodiment of the present disclosure;

fig. 1N illustrates uplink transmission resource allocation in a paging PDCCH for fast reconnection according to an embodiment of the present disclosure;

fig. 1O illustrates uplink transmission resource allocation in a paging PDCCH for fast reconnection according to an embodiment of the present disclosure;

fig. 1P illustrates a fast network reconnection method using a Paging Channel (PCH) configuration including a (uplink shared channel) UL-SCH in accordance with an embodiment of the present disclosure;

fig. 1Q illustrates uplink transmission resource allocation and indicator addition in a paging PDCCH for fast reconnection according to an embodiment of the present disclosure;

fig. 1R illustrates uplink transmission resource allocation and indicator addition in a paging PDCCH for fast reconnection according to an embodiment of the present disclosure;

fig. 1S illustrates uplink transmission resource allocation and indicator addition in a paging PDCCH for fast reconnection according to an embodiment of the present disclosure;

fig. 1T illustrates a fast network reconnection method using a paging PCH configuration including an UL-SCH and an indicator in accordance with an embodiment of the present disclosure;

fig. 1U is a diagram illustrating transmitting an RNTI according to an embodiment of the present disclosure;

fig. 1V is a diagram illustrating a fast network reconnection method using a paging PCH configuration including a dedicated Random Access Channel (RACH) preamble according to an embodiment of the present disclosure;

fig. 1W is a diagram illustrating transmission of a paging message and a preamble according to an embodiment of the present disclosure;

fig. 1X is a diagram illustrating a fast network reconnection method using a paging message including a dedicated RACH preamble according to an embodiment of the present disclosure;

fig. 1Y is a diagram illustrating a terminal according to an embodiment of the present disclosure;

fig. 1Z is a diagram illustrating a base station according to an embodiment of the present disclosure;

fig. 2A is a diagram illustrating a multi-beam system according to an embodiment of the present disclosure;

fig. 2B is a diagram illustrating a frame structure for feeding back multi-beam IDs and beam measurements according to an embodiment of the present disclosure;

fig. 2C is a diagram illustrating a frame structure for feeding back multi-beam IDs and beam measurements according to an embodiment of the present disclosure;

fig. 2D is a diagram illustrating a frame structure for feeding back multi-beam IDs and beam measurements according to an embodiment of the present disclosure;

fig. 2E is a diagram illustrating beam changes through beam feedback according to an embodiment of the present disclosure;

fig. 2F and 2G are diagrams illustrating a frame structure for transmitting beam feedback according to an embodiment of the present disclosure;

fig. 2H is a diagram illustrating operations of a base station and a terminal for changing a currently used base station beam to a base station beam having an on indicator according to an embodiment of the present disclosure;

fig. 2I is a diagram illustrating operations of a base station and a terminal in a case where an indicator specifies that the base station can freely change without transmitting a Beam Change Indication (BCI) to the terminal according to an embodiment of the present disclosure;

fig. 2J is a diagram illustrating operations of a base station and a terminal according to a first beam feedback transmission method for selecting a beam for use at an initial connection, according to an embodiment of the present disclosure; and

fig. 2K-2P illustrate a method of a terminal attempting a beam recovery request transmission when a certain condition is satisfied in association with a Radio Link Failure (RLF) operation according to an embodiment of the present disclosure.

Detailed Description

Embodiments of the present disclosure are described in detail with reference to the drawings, wherein like reference numerals may be used to refer to like elements throughout. However, it should be understood that: it is not intended to be limited to the specific form set forth herein; on the contrary, the disclosure is to be construed as covering various modifications, equivalents, and/or alternatives to the embodiments of the disclosure.

In the present disclosure, the terms "base station" and "eNB" may be used interchangeably. In addition, the terms "terminal" and "User Equipment (UE)" may be used interchangeably.

Example a: inactive UE ID

With the advent of smart phones, the use of smart phones has grown exponentially, and there is a growing need to increase battery life to use smart phones for long periods of time. This means that an efficient power saving technique is required and the terminal is also required to operate in a power saving state. For efficient power saving of a terminal, various techniques have been proposed and standardized in order to make the terminal operate in a power saving state more frequently and to reestablish a connection with a network more quickly.

Typical power saving techniques in smart phones are: a power saving State UE operation in a sub-State of an RRC Connected State (RRC Connected State), a power saving State UE operation in a sub-State of an RRC IDLE State (RRC IDLE State), or a power saving State UE operation in a new RRC State, an LTE light Connected State operation, a 5G NR RRC _inactivestate operation, and a WLAN (IEEE 802.11) power saving mode operation.

If no information is transmitted/received for a certain period of time or if another condition is satisfied, the terminal performs a transition to a power saving state (LC: a lightly connected state, INACTIVE: RRC _ INACTIVE state). This state differs from the IDLE state in that: the base station and the terminal hold (main) terminal information and network connection information of the terminal (S1 information), and the core network assumes that the terminal is still in a Connected state (RRC _ Connected). The reason for maintaining the S1 information in this way is that the network can thus perform reconnection of the terminal very quickly. Terminal operating in power saving state: if there is information to send, it will wake up itself and reconnect to the network; and if the base station receives any downlink information from the network, it will wake up through the base station's page and reconnect with the network.

For paging of base stations (RAN-based paging), a group (bundle) of base stations that transmit a page is defined as a RAN paging area, and corresponding information is provided to a terminal. A terminal that is aware of RAN paging area information periodically wakes up during power save state operation and determines whether the terminal is still in a known RAN paging area. If so, the terminal should check the committed subframe (committed subframe) to determine if downlink paging information is present. If the terminal leaves the RAN paging area while sleeping, the terminal should re-establish a connection with a neighboring base station and perform RAN paging area update.

Fig. 1A illustrates a structure for RAN page transmission according to an embodiment of the present disclosure, including a core network, a base station, and a terminal.

In order to transmit paging information to a terminal operating in a power saving state, a terminal identifier for identifying the terminal is required, and a procedure for transmitting a paging message including the identifier may be required.

In the case of idle mode paging (i.e., CN paging) sent by a Mobility Management Entity (MME), a paging radio network temporary identifier (P-RNTI) is used to specify a subframe in which there is paging.

If there is a terminal that receives any paging, the P-RNTI is transmitted while including the P-RNTI in a Physical Downlink Control Channel (PDCCH) of a subframe that is received by a periodically awake terminal at a given paging occasion.

Fig. 1B illustrates a paging receiving method of a terminal operating in a power saving state according to an embodiment of the present disclosure.

Referring to fig. 1B, in operation 1B-05, a base station receives a paging message for a terminal from an MME.

In operation 1b-10, the base station transmits the P-RNTI on the PDCCH of the subframe received by the periodically awake terminal at a given paging occasion.

In operation 1b-15, the terminal receives the P-RNTI and determines that the corresponding subframe includes a paging message to be transmitted.

In operation 1b-20, the base station transmits a paging message through a Physical Downlink Shared Channel (PDSCH) of the same subframe or a PDSCH of a subframe indicated through a PDCCH. The paging message may include a System Architecture Evolution (SAE) -temporary mobile subscriber identity (S-TMSI) or International Mobile Subscriber Identity (IMSI), which is a unique terminal ID in the MME.

In operation 1b-25, the terminal checks whether the S-TMSI or IMSI, which is an identifier corresponding to the terminal, is included in the corresponding subframe. If included, operations 1b-30 are performed. If not, operations 1b-35 are performed. In operation 1b-30, the terminal performs a network reconnection operation. In operations 1b-35, the terminal resumes sleep operation. The terminal may perform a sleep operation until the next paging occasion.

A method of specifying a RAN paging subframe by defining a new RNTI will now be described.

The method is for defining a new RNTI (RAN paging RNTI: RP-RNTI) different from the P-RNTI, and for enabling a base station to perform paging for a terminal through the RP-RNTI.

The base station may transmit the P-RNTI and/or the RP-RNTI through a PDCCH of a subframe received by the periodically awake terminal at a given paging occasion. The transmission method may be a method of scrambling a Cyclic Redundancy Check (CRC) of transmitted Downlink Control Information (DCI). A terminal receiving the PDCCH in one subframe can distinguish CN paging and RAN paging through P-RNTI and RP-RNTI, and can distinguish a terminal corresponding to CN paging and RAN paging through P-RNTI and RP-RNTI. At this time, only a terminal receiving its own P-RNTI or RP-RNTI can additionally decode the PDSCH, and other terminals can quickly return to the sleep mode.

Table 1 shows new RNTI values, while table 2 shows an example of using a new RNTI.

In addition, figure 1C illustrates a method for using a new RNTI for RAN paging in accordance with an embodiment of the present disclosure.

TABLE 1

Value (hexadecimal)	RNTI
		…	…
FFFC	RP-RNTI
		FFFE	P-RNTI
…	…

TABLE 2

Referring to fig. 1C, a base station, a RAN paging terminal, and an idle terminal are included.

In operation 1c-05, the base station receives a paging message for the terminal from the MME or a paging request including terminal ID information and a paging message for the terminal from the base station in the RAN paging area.

In operation 1c-10, the base station transmits the RP-RNTI through a PDCCH of a subframe which is a paging occasion of the terminal. The base station may send the RP-RNTI on the PDCCH of the subframe that is the paging occasion for the corresponding terminal to the RAN paging terminal and/or the idle terminal.

In operation 1c-20, the idle terminal receiving the RP-RNTI recognizes that the RP-RNTI is different from the P-RNTI and resumes the sleep operation. The idle terminal may maintain (maintain) sleep state until the next paging occasion.

In operation 1c-15, the RAN paging terminal receiving the RP-RNTI recognizes that the subframe receiving the RP-RNTI includes a paging message transmitted to a specific terminal.

In operation 1c-25, the base station transmits a paging message through a PDSCH of the same subframe as that in which the RP-RNTI is transmitted or a PDSCH of a subframe indicated by a PDCCH including the RP-RNTI. The paging message may include an S-TMSI or IMSI, which is a unique terminal ID in the MME. Operations 1c-25 may be performed concurrently with operations 1 c-10. That is, information corresponding to operations 1c-10 may be transmitted on a PDCCH of the same subframe and information corresponding to operations 1c-25 may be transmitted on a PDSCH. This also applies to other embodiments of the present disclosure.

In operation 1c-30, the ran paging terminal checks whether its own S-TMSI or IMSI is included in the paging message. If the paging message includes an S-TMSI or IMSI corresponding to the RAN paging terminal, operations 1c-40 are performed. If the paging message does not include the S-TMSI or IMSI corresponding to the RAN paging terminal, operations 1c-45 are performed.

In operations 1c-40, the ran paging terminal recognizes the paging message for itself and performs a network reconnection operation. In operations 1c-45, the ran paging terminal recognizes that the paging message is not for itself and resumes sleep operation. The RAN paging terminal may maintain the sleep state until the next paging occasion.

A method of distinguishing RAN paging by defining a new UE specific ID will now be described.

The method is for defining a new UE-specific ID (RAN paging TMSI: RP-TMSI) different from S-TMSI and IMSI, and for enabling a base station to perform paging for a terminal by using the RP-TMSI.

A terminal receiving a paging message through the PDSCH in one subframe may recognize that the corresponding paging message designates the terminal itself operating in RAN paging.

Table 3 shows the PagingUE-Identity field value including the new UE ID.

TABLE 3

The RP-TMSI may be a unique UE ID under the MME, a unique UE ID in the RAN paging area, or a unique UE ID in the eNB.

FIG. 1D illustrates various methods for constructing an RP-TMSI (or a new TMSI) in accordance with embodiments of the present disclosure.

Figure 1E illustrates RAN and CN paging procedures when adding an RP-TMSI and the operation of the corresponding terminal according to an embodiment of the present disclosure.

A procedure in which the system uses the same RNTI (P-RNTI) as the RNTI for CN paging and RAN paging, and uses a method of distinguishing UEs with UE-specific IDs is shown in fig. 1E.

Referring to fig. 1E, in operation 1E-05, a base station receives a paging message for a terminal from an MME or a paging request including terminal ID information and a terminal paging message from a base station in a RAN paging area.

In operation 1e-10, the base station transmits the P-RNTI through a PDCCH of a subframe which is a paging occasion of the terminal. The base station may send the P-RNTI on the PDCCH of the subframe as a paging occasion for the corresponding terminal to the RAN paging terminal and/or idle terminal.

In operation 1e-15, a RAN paging terminal receiving a P-RNTI recognizes that a subframe receiving the P-RNTI includes a paging message to be transmitted to a specific terminal. In operation 1e-20, an idle terminal receiving the P-RNTI recognizes that a subframe receiving the P-RNTI includes a paging message to be transmitted to a specific terminal.

In operation 1e-25, the base station transmits a paging message through a PDSCH of the same subframe as a subframe in which the P-RNTI is transmitted or a subframe indicated by a PDCCH including the P-RNTI. The paging message may include RP-TMSI, S-TMSI, or IMSI, which is the unique terminal ID in the MME.

In operation 1e-30, the RAN paging terminal checks whether the paging message includes its own RP-TMSI or IMSI. If the RP-TMSI or IMSI corresponding to the RAN paging terminal is included in the paging message, operations 1e-35 are performed. If the paging message does not include the RP-TMSI or IMSI corresponding to the RAN paging terminal, operations 1e-40 are performed.

In operations 1e-35, the ran pages the terminal to recognize that the paging message is for itself and performs a network reconnection operation. In operations 1e-40, the ran paging terminal recognizes that the paging message is not for itself, and resumes the sleep operation. The RAN paging terminal may maintain the sleep state until the next paging occasion.

In operation 1e-45, the idle terminal checks whether the paging message includes its own S-TMSI or IMSI. If the paging message includes an S-TMSI or IMSI corresponding to the idle terminal itself, operations 1e-50 are performed. If the paging message does not include the S-TMSI or IMSI corresponding to the idle terminal itself, operations 1e-55 are performed.

In operation 1e-50, the idle terminal recognizes the paging message for itself and performs a network reconnection operation. In operation 1e-55, the idle terminal recognizes that the paging message is not for itself, and resumes the sleep operation. The idle terminal may maintain the sleep state until the next paging occasion.

A method for using both the new RNTI and the new UE-specific ID will now be described.

FIG. 1F illustrates a method for using both RP-RNTI and RP-TMSI in accordance with an embodiment of the disclosure.

The operation procedure of the terminal when RAN paging is performed using both the new RNTI (RP-RNTI) and the new UE-specific ID (RP-TMSI) proposed above is shown in fig. 1F.

Referring to fig. 1F, in operation 1F-05, a base station receives a paging message for a terminal from an MME or a paging request including terminal ID information and a terminal paging message from a base station in a RAN paging area.

In operation 1f-10, the base station transmits the RP-RNTI through a PDCCH of a subframe which is a paging occasion of the terminal. The base station may send the RP-RNTI to the RAN paging terminal and/or idle terminal on the PDCCH of the subframe that is the paging occasion for the corresponding terminal.

In operation 1f-20, the idle terminal receiving the RP-RNTI recognizes that the RP-RNTI is different from the P-RNTI and resumes the sleep operation. The idle terminal may maintain the sleep state until the next paging occasion.

In operation 1f-15, the RAN paging terminal receiving the RP-RNTI recognizes that the subframe receiving the RP-RNTI includes a paging message transmitted to a specific terminal.

In operation 1f-25, the base station transmits a paging message through a PDSCH of the same subframe as that in which the RP-RNTI is transmitted or a PDSCH of a subframe indicated by the PDCCH including the RP-RNTI. The paging message may include the RP-TMSI or IMSI, which is the unique terminal ID in the MME.

In operation 1f-30, the RAN paging terminal checks whether the paging message includes its own RP-TMSI or IMSI. If the RP-TMSI or IMSI corresponding to the RAN paging terminal is included in the paging message, operations 1f-40 are performed. If the paging message does not include the RP-TMSI or IMSI corresponding to the RAN paging terminal, operations 1f-45 are performed.

In operation 1f-40, the ran pages the terminal to recognize that the paging message is for itself and performs a network reconnection operation. In operations 1f-45, the ran paging terminal recognizes that the paging message is not for itself and resumes sleep operation. The RAN paging terminal may maintain the sleep state until the next paging occasion.

The method for allocating a unique terminal ID in a RAN paging area by a base station in the RAN paging area may include the following operations (1) - (4).

(1) A method of allocation by a management agent, comprising:

(A) Selecting a base station; and

(B) And allocating the MME.

(2) There is no arbitrary allocation method to manage principals.

(3) An allocation method within the unique ID pool of each base station.

(4) A method for mutually advertising distributed IDs allocated by base stations.

A method of paging a terminal by the last serving base station and the neighbor base stations using different RNTIs will now be described.

The last serving base station that the terminal accesses before performing the transition to the power saving state has the C-RNTI of the terminal and also maintains the S1 connection to exchange information between the terminal and the core network. With this feature, the last serving base station can perform more efficient paging using a different method from other base stations in the RAN paging area of the corresponding terminal.

The base station and the terminal operate as follows. A terminal operating in a power saving state wakes up periodically and checks a committed subframe at an agreed (agreed) time to check whether paging information is received. To this end, the terminal periodically wakes up, re-establishes downlink synchronization before receiving a subframe and selects a camping cell by selecting a cell receiving the subframe (the same or similar to the cell reselection operation in idle mode).

Fig. 1G illustrates a method of simplifying paging by using a C-RNTI by a last serving base station according to an embodiment of the present disclosure.

Referring to fig. 1G, base stations in a RAN paging area other than a last serving base station to which a terminal is connected may not use C-RNTI of the corresponding terminal, and thus paging for the terminal should be performed by using P-RNTI or RP-RNTI. However, the serving base station may finally perform paging using the C-RNTI of the known (know) terminal. In this case, the C-RNTI may be transmitted while being included in the PDCCH (by scrambling the CRC of the DCI), and a resource scheduling (RB) size in the PDCCH including the C-RNTI may be set to zero. If there is a PDCCH message including C-RNTI (scrambled with C-RNTI) in a subframe in a paging occasion received by a periodically awake terminal, the terminal can recognize that there is downlink data to receive (it is determined that paging is successfully received) and attempt to reconnect to the network. At this time, if the resource scheduling size is zero except for the C-RNTI, the terminal may perform the above operation.

Referring to fig. 1G, in operation 1G-05, the serving base station finally receives a paging message for the terminal from the MME.

In operations 1g-10, the serving base station finally transmits a paging request including terminal ID information and a terminal message to base stations in a RAN paging area (RAN PA).

In operations 1g-15, the last serving base station transmits the C-RNTI to the terminal in the last serving base station region through the PDCCH of the subframe as a paging occasion of the terminal. At this time, the RB size in the PDCCH including the corresponding C-RNTI may be set to zero.

A base station in the ran PA may transmit a P-RNTI or RP-RNTI to terminals in its area in operation 1 g-20. The base station in the RAN PA may send the RP-RNTI or the P-RNTI to the PDCCH of the subframe that is the paging occasion of the terminal.

In operations 1g-25, a terminal in the last serving base station region that received a message in a PDCCH that includes a C-RNTI or includes a C-RNTI with an RB size set to zero recognizes that the page is for the terminal itself in the corresponding subframe. When there is a PDCCH message including C-RNTI (scrambled with the C-RNTI), the terminal may recognize that there is downlink data to be received (it is determined that paging is successfully received), and may attempt to reconnect to the network in operations 1 g-40.

In operation 1g-30, a terminal receiving a P-RNTI or RP-RNTI confirms that a subframe receiving the P-RNTI or RP-RNTI includes a CN paging message or a RAN paging message transmitted to a specific terminal.

In operation 1g-35, the base station transmits a paging message through a PDSCH of the same subframe as a subframe in which the P-RNTI or the RP-RNTI is transmitted or a PDSCH of a subframe indicated by a PDCCH including the P-RNTI or the RP-RNTI. The paging message may include RP-TMSI, S-TMSI, or IMSI, which is the unique terminal ID in the MME.

In operation 1g-45, a terminal in the base station area in the RAN PA checks whether the paging message includes its own RP-TMSI, S-TMSI, or IMSI. If the paging message includes RP-TMSI, S-TMSI, or IMSI corresponding to the terminal itself, operations 1g-50 are performed. If the paging message does not include the RP-TMSI, S-TMSI, or IMSI corresponding to the terminal itself, operations 1g-55 are performed.

In operation 1g-50, the terminal recognizes that the paging message is for itself and performs a network reconnection operation. In operation 1g-55, the terminal recognizes that the paging message is not for itself, and resumes the sleep operation. The terminal may maintain the sleep state until the next paging occasion.

Fig. 1HA and 1HB illustrate a method in which a last serving base station transmits a C-RNTI included in a paging message according to an embodiment of the present disclosure.

Referring to fig. 1HA and fig. 1HB, when a base station in a RAN paging area performs paging for a terminal by using P-RNTI and RP-RNTI and transmits a paging message for a PDSCH designating the terminal, a last serving base station can transmit C-RNTI that is aware of the terminal. In this case, other base stations in the RAN paging area may use RP-TMSI, S-TMSI, or IMSI instead of C-RNTI.

In operation 1h-05, the serving base station finally receives a paging message for the terminal from the MME.

In operation 1h-10, the last serving base station sends a paging request including terminal ID information and a terminal message to base stations in a RAN paging area (RAN PA).

In operation 1h-15, the last serving base station transmits the P-RNTI or the RP-RNTI to the terminal in the last serving base station region through the PDCCH, which is a subframe of the paging occasion of the terminal. In operation 1h-20, the base station in the RAN PA sends either the P-RNTI or the RP-RNTI to the terminals in its area. A base station in the RAN PA may send the RP-RNTI or the P-RNTI to a PDCCH of a subframe that is a paging occasion of the terminal. In operation 1h-25, a terminal in the last serving base station area receiving the P-RNTI or RP-RNTI recognizes that a subframe receiving the P-RNTI or RP-RNTI includes a CN paging message or RAN paging message transmitted to a specific terminal. In operation 1h-30, a terminal receiving the P-RNTI or RP-RNTI recognizes that a subframe receiving the P-RNTI or RP-RNTI includes a CN paging message or a RAN paging message transmitted to a specific terminal.

In operation 1h-35, the last serving base station transmits a paging message through a PDSCH of the same subframe as the subframe in which the P-RNTI or RP-RNTI is transmitted or a PDSCH of a subframe indicated by a PDCCH including the P-RNTI or RP-RNTI. The paging message may include the C-RNTI.

In operation 1h-45, the terminal in the last serving base station area checks whether the C-RNTI as the terminal ID is included in the paging message. If the C-RNTI is included in the paging message, operations 1h-50 are performed. Otherwise, operations 1h-55 are performed. In operation 1h-50, the terminal recognizes that the paging message is for itself, and performs a network reconnection operation. In operation 1h-55, the terminal recognizes that the paging message is not for itself, and resumes the sleep operation. The terminal may maintain the sleep state until the next paging occasion.

In operation 1h-40, the base station in the RAN PA transmits a paging message through a PDSCH of the same subframe as that of the P-RNTI or the RP-RNTI or a PDSCH of a subframe indicated by a PDCCH including the P-RNTI or the RP-RNTI. The paging message may include RP-TMSI, S-TMSI, or IMSI, which is the unique terminal ID in the MME.

In operation 1h-60, a terminal in the base station area in the RAN PA checks whether the paging message includes its own RP-TMSI, S-TMSI or IMSI. If the paging message includes RP-TMSI, S-TMSI or IMSI corresponding to the terminal itself, operation 1h-65 is performed. If the paging message does not include RP-TMSI, S-TMSI or IMSI corresponding to the terminal itself, operations 1h-70 are performed.

In operation 1h-65, the terminal recognizes that the paging message is for itself, and performs a network reconnection operation. In operation 1h-70, the terminal recognizes that the paging message is not for itself, and resumes the sleep operation. The terminal may maintain the sleep state until the next paging occasion.

A method of distinguishing RAN-based paging by adding an indicator will now be described.

There may be a method of distinguishing paging by using RNTI and TMSI instead of using new RNTI and TMSI and also by adding an indicator to other fields.

A method for adding a 1-bit indicator to DCI in a PDCCH is as follows.

Table 4 shows a 1-bit RAN paging indicator for DCI format 1A/1C, and table 5 shows a 2-bit RAN paging indicator for DCI format 1A/1C.

TABLE 4

TABLE 5

A method of distinguishing RAN paging from CN paging by adding a 1-bit indicator in addition to UE identity in PDSCH is as follows. Table 6 shows a 1-bit RAN paging indicator after paging ue-identity.

TABLE 6

A terminal receiving the above indicator can distinguish whether a corresponding paging UE-identity and a paging message are a RAN page or a CN page, perform an operation according to its own state and ignore pages transmitted for other state purposes.

A new RAN paging Discontinuous Reception (DRX) configuration will now be described.

In the new power saving state, the terminal performs sleep and awake operations, such as idle mode operations, according to certain rules. Such discontinuous reception operation of the terminal is called DRX and terminal DRX operation in a power saving state should be signaled and controlled by the base station.

The DRX cycle of the terminal can be signaled and controlled in the following manner.

Table 7 shows INACTIVE (INACTIVE) paging cycles in DRX configuration, while table 8 shows INACTIVE paging cycles in PDCCH configuration.

TABLE 7

TABLE 8

When RAN paging is newly defined as above and signaled in an environment where two kinds of paging coexist such as CN paging and RAN paging, a system (a base station and a terminal) may configure and use CN paging and RAN paging with different paging occasions and paging cycles. In this case, the terminal operating in the power saving state may use only the RAN paging cycle, and the terminal operating in the idle mode may use only the CN paging cycle. In addition, a terminal desiring more frequent and faster page reception, such as SI update or radio link failure recovery (cell reselection), may check both paging occasions regardless of the state of the terminal. Of course, in this case, power consumption may be increased due to frequent paging of the terminal, compared to the case of receiving only one paging type.

Fig. 1I illustrates an environment where CN paging and RAN paging with different periods and paging occasions coexist according to an embodiment of the present disclosure.

An example of a terminal configured for CN paging and RAN paging to have different periods is shown in fig. 1I.

On the other hand, terminals configured for CN paging and RAN paging to have the same period and have different states (idle and power saving) may wake up simultaneously. In this case, if there is a new RAN paging DRX configuration, the corresponding value may be set to be the same as the CN paging and may be signaled. In addition, the CN paging configuration may be used for RAN paging without adding a new DRX configuration.

An example configuration for reusing (reuse) CN paging in RAN paging is shown in fig. 1J and table 9.

Fig. 1J shows an environment where CN paging and RAN paging coexist with the same period and paging occasion, and table 9 shows a RadioResourceConfigCommon field description.

TABLE 9

Alternatively, the indicator may be used to inform the terminal that the CN paging and the RAN paging in the PCCH configuration are the same.

Table 10 shows an inactive paging cycle in a PDCCH configuration with an indicator, and table 11 shows a RadioResourceConfigCommon field description.

TABLE 10

TABLE 11

A method for deleting terminal information at a terminal, a base station, and a network will now be described.

When the terminal performs a transition to an idle state or cannot use the network due to an inevitable change, unique information of the terminal operating in the power saving state and network connection information should be deleted from the terminal and the base station. The information deletion timing of the terminal and the network may be a case where various conditions are satisfied, and these conditions are as follows.

The opportunity (when) for the UE to reconnect to the other cell may be satisfied when (a) the UE itself reconnects to the other cell and reconfigures or (b) the other cell signals the last serving cell that the UE reconnects.

The timing of the UE updated paging area may be satisfied when (a) the UE itself moves out of the RAN paging area and successfully updates the paging area or (b) other cells send a signal to the last serving cell that the UE updates the RAN paging area.

In case (a) the Reference Signal Received Power (RSRP), the Reference Signal Received Quality (RSRQ), the Channel Quality Indicator (CQI), the signal-to-interference-plus-noise ratio (SINR), the signal-to-noise ratio (SNR) of the serving channel is less than threshold1 (threshold 1), or (b) the currently measured RSRP, RSRQ, CQI, SINR of the serving channel is less than the last measured RSRP, RSRQ, CQI, SINR, SNR of the serving channel (threshold 2)), when the channel quality degradation is measured at this time, in case the eNB indicates a signal (RRC message, MAC message), the occasion of the UE state change to idle mode (UE operation) may be satisfied. Alternatively, the UE status change to idle mode (UE operation) may be satisfied by expiration of a timer started at the last successful data transmission/reception (tx/rx), the last channel measurement result.

(a) When the number of paging retransmissions reaches a maximum threshold3 (threshold 3); (b) When channel quality degradation is measured if (i) RSRP, RSRQ, CQI, SINR, SNR of the serving channel is less than threshold1 (threshold 1), or (ii) currently measured RSRP, RSRQ, CQI, SINR, SNR of the serving channel is less than the last measured RSRP, RSRQ, CQI, SINR, SNR of the serving channel (threshold 2); (c) expiration by a timer; or (d) the maximum threshold4 (threshold 4) is reached by the number of NACK (or non-ACK) responses, which may satisfy the timing when the eNB detects that the UE is no longer in the power saving state.

A method for transmitting a page for system information update will now be described.

In 5G, the system information may be divided into two or more components. Herein, the minimum system information periodically transmitted for network connection may be referred to as a minimum SI, and other system information transmitted through broadcasting or unicasting (on demand) may be referred to as an additional SI. In this case, the minimum SI and the additional SI may be updated at the same period, or only one of the minimum SI and the additional SI may be updated.

In order to update different kinds of system information, the next standard may set a system information update period to two or more different periods. In this case, the different system information update periods may be as follows.

Table 12 shows the minimum/additional SI update period in TS36.331 (3 gpp standard specification number), and table 13 shows the minimum/additional SI update period in TS 36.331.

TABLE 12

Watch 13

Fig. 1K illustrates minimum/additional SI modification period operation in accordance with an embodiment of the present disclosure.

The periods for updating different kinds of system information may be individually allocated to different times so as not to overlap with each other, as shown in fig. 1K. When system information update and change notification therefor are performed in such non-overlapping times, the terminal may update only corresponding information in a corresponding period after receiving a specific change notification. Therefore, the terminal may not need to update all the system information. Alternatively, it is possible to allocate different periods to the same time so as to overlap each other.

To update heterogeneous system information, the system may transmit a paging message including a change notification in a period immediately before a modification period in which the system information is actually updated. The paging message may be a CN page, a RAN page, or both.

A terminal connected to the network, operating in a power saving state in the network or residing in the network receives such paging information and updates system information in the next modification period.

At this time, the system information update (change) notification included in the paging message may be classified into the minimum SI and the additional SI. This may be reflected in the terminal operation as follows.

Table 14 shows the minimum/additional SI update for the UE in TS 36.331.

TABLE 14

Alternatively, the case where the reception of the additional SI information is performed on demand at the time of the UE request is as follows:

table 15 shows the minimum/additional SI update for the UE in TS 36.331.

Watch 15

When receiving paging information including a change notification indicating that system information will change soon, each paging information reception cycle may be considered to be smaller than a modification period (paging cycle < modification period) in which the change notification is continuously transmitted. In this case, the terminal receives the paging message including the same change notification every time, and this information is not only redundant but also causes power consumption of the terminal. Accordingly, if the terminal decodes only the paging message including the first notification, and if the paging message including only the same SI update change notification among the paging messages transmitted in the same modification period can be distinctively ignored, power consumption of the terminal can be reduced.

To this end, embodiments of the present disclosure propose a new paging information identifier (SIU-RNTI), as described below.

If paging is used only for SI update notification, SIU-RNTI is used. SIU-RNTI (P-RNTI may be used) may not be used if the page contains other information, such as data pages. A UE receiving one SI update may ignore other SIU-RNTIs during the same BCCH modification period.

Table 16 shows new RNTI values for SI updates, and [ fig. 1L ] shows an embodiment of SIU update operations according to the present disclosure.

TABLE 16

Value (hexadecimal)	RNTI
		…	…
FFFB	SIU-RNTI
		FFFE	P-RNTI
…	…

A method in which a terminal operating in a power saving state quickly reconnects to a network will now be described.

There may be various methods by which a terminal operating in a power saving state is quickly reconnected to a network. The method considered by the present disclosure is used when the uplink channel and the downlink channel have similar characteristics due to a short distance between the transmitting end and the receiving end and also due to similar synchronization. In this method, uplink resources are occupied in downlink paging information, and a terminal immediately performs uplink transmission without a special uplink synchronization operation (e.g., RACH). The detailed procedure of uplink transmission resource allocation in the paging PDCCH for fast reconnection is as follows:

the base station transmits UL-SCH resource reservation (reservation) for a response from the terminal (or recovery request transmission of the terminal) included in the paging PDCCH, and the terminal receiving this recognizes that the corresponding paging message is a request for network reconnection of the terminal (via an implicit indication of UL-SCH configuration).

According to embodiments of the present disclosure, a C-RNTI + paging PCH + UL SCH configuration may be employed.

Fig. 1M illustrates uplink transmission resource allocation in a paging PDCCH for fast reconnection according to an embodiment of the present disclosure.

A base station (e.g., the last serving eNB) having a C-RNTI previously used (or promised) with the terminal transmits a paging PDCCH using the C-RNTI to request the terminal operating in the power saving state to reconnect to the network (connection recovery). At this time, more than 3 Transmission Time Intervals (TTIs) later in time should be allocated to the UL-SCH resource allocation compared to the paging message transmission resource allocated by the paging PCH configuration. The terminal receiving the message receives paging information through the paging PCH and transmits a connection recovery request on the UL-SCH. After successfully completing the transmission/reception of the connection restoration request, the network and the terminal recognize the completion of the connectivity and perform the transition of the terminal state to RRC _ CONNECTED.

According to embodiments of the present disclosure, a C-RNTI + UL SCH configuration may be employed.

Fig. 1N illustrates uplink transmission resource allocation in a paging PDCCH for fast reconnection according to an embodiment of the present disclosure.

A base station (e.g., the last serving eNB) having a C-RNTI previously used (or promised) with the terminal transmits a paging PDCCH using the C-RNTI to request the terminal operating in the power saving state to reconnect to the network (connection recovery). The terminal receiving the message transmits a connection recovery request on the UL-SCH. After successfully completing transmission/reception of the connection restoration request, the network and the terminal recognize that the connectivity is completed, and perform transition of the terminal state to RRC _ CONNECTED.

According to embodiments of the present disclosure, RNTI + paging PCH + UL SCH configurations may be employed.

Fig. 1O illustrates uplink transmission resource allocation in a paging PDCCH for fast reconnection according to an embodiment of the present disclosure.

The base station transmits a paging PDCCH using the RNTI to request the terminal operating in the power saving state to reconnect to the network (connection recovery). At this time, more than 3 TTIs later in time should be allocated to the UL-SCH resource allocation compared to the paging message transmission resource allocated by the paging PCH configuration. The terminal receiving the message receives paging information through the paging PCH and transmits a connection recovery request on the UL-SCH if the received information contains its UE-specific ID. After successfully completing the transmission/reception of the connection restoration request, the network and the terminal recognize the completion of the connectivity and perform the transition of the terminal state to RRC _ CONNECTED.

Fig. 1P illustrates a fast network reconnection method using a paging PCH configuration including UL-SCH in accordance with an embodiment of the present disclosure.

Referring to fig. 1P, the system includes a base station and a terminal. The terminal may be in a Light Connection (LC) state or in an inactive state.

In operation 1p-05, the base station transmits a paging PDCCH to the terminal using the RNTI. The RNTI may be at least one of a P-RNTI, a C-RNTI, or an RP-RNTI. The paging PDCCH may include a paging PCH configuration and also an UL-SCH configuration. The UL-SCH configuration resource may be allocated a subframe or TTI later in time than a paging message transmission resource allocated by the paging PCH configuration. The UL-SCH resource may be allocated more than 3 TTIs later than the paging message transmission resource.

In operation 1p-10, a base station transmits a paging message to a terminal. The paging message may include a terminal identifier, which may include at least one of an IMSI, S-TMSI, C-RNTI, and RP-TMSI.

In operation 1p-15, the terminal receives paging information through the paging PCH and checks whether the received information contains its own terminal identifier.

If the terminal identifier does not exist, the terminal proceeds to operation 1p-20. In operation 1p-20, the terminal performs a sleep operation until the next paging occasion.

If there is its own terminal identifier, the terminal proceeds to operation 1p-25. In operation 1p-25, the terminal transmits an RRC connection recovery request through the UL-SCH. The UL-SCH transmission resource may use the UL-SCH resource allocated at operation 1 p-10.

In operation 1p-30, the base station may transmit a Random Access Response (RAR) and an RRC connection recovery to the terminal. The terminal may receive the RAR through the PDSCH. If transmission and reception of the RRC connection restoration request and RRC connection restoration are successfully completed, the network and the terminal may recognize that the connectivity is completed and may perform a transition of the terminal state to RRC _ CONNECTED.

A method of uplink transmission resource allocation and indicator addition in the paging PDCCH for fast reconnection will now be described.

The base station transmits an UL-SCH resource reservation for a response from the terminal (or a recovery request transmission of the terminal) included in the paging PDCCH, and also transmits an indicator using the resource to request the terminal to perform reconnection. The terminal recognizes that the corresponding message is a request for network reconnection of the terminal (explicit indication). At this time, the indicator may be included in the UL-SCH configuration.

Fig. 1Q illustrates uplink transmission resource allocation and indicator addition in a paging PDCCH for fast reconnection according to an embodiment of the present disclosure.

A base station (e.g., last serving eNB) having a C-RNTI that was previously used (or promised) with the terminal transmits a paging PDCCH using the C-RNTI to request the terminal operating in a power saving state to reconnect to the network (connection resumption). At this time, more than 3 TTIs later in time should be allocated to the UL-SCH resource allocation compared to the paging message transmission resource allocated by the paging PCH configuration. The terminal receiving the message receives paging information through the paging PCH and transmits a connection resumption request on the UL-SCH if the reconnection request indicator is a predetermined value (typically 1). Upon successful completion of transmission/reception of the connection restoration request, the network and the terminal recognize that the connectivity is completed, and perform transition of the terminal state to RRC _ CONNECTED.

Fig. 1R illustrates uplink transmission resource allocation and indicator addition in a paging PDCCH for fast reconnection according to an embodiment of the present disclosure.

A base station (e.g., the last serving eNB) having a C-RNTI previously used (or promised) with the terminal transmits a paging PDCCH using the C-RNTI to request the terminal operating in the power saving state to reconnect to the network (connection recovery). If the reconnection request indicator is a predetermined value (typically 1), the terminal receiving the message transmits a connection resumption request on the UL-SCH. Upon successful completion of transmission/reception of the connection restoration request, the network and the terminal recognize that the connectivity is completed, and perform transition of the terminal state to RRC _ CONNECTED.

Fig. 1S illustrates uplink transmission resource allocation and indicator addition in a paging PDCCH for fast reconnection according to an embodiment of the present disclosure.

The base station transmits a paging PDCCH using the RNTI to request the terminal operating in the power saving state to reconnect to the network (connection recovery). At this time, more than 3 TTIs later in time should be allocated to the UL-SCH resource allocation compared to the paging message transmission resource allocated by the paging PCH configuration. The terminal receiving the message receives paging information on the paging PCH and sends a connection recovery request on the UL-SCH if the reconnection request indicator is a predetermined value (typically 1) and if the received information contains its UE-specific ID. Upon successful completion of the transmission/reception of the connection restoration request, the network and the terminal recognize the completion of the connectivity and perform the transition of the terminal state to RRC _ CONNECTED.

Fig. 1T shows a fast network reconnection method using a paging PCH configuration including an UL-SCH and an indicator.

Referring to fig. 1T, the system includes a base station and a terminal. The terminal may be in a Light Connection (LC) state or in an inactive state.

In operation 1t-05, the base station transmits a paging PDCCH to the terminal using the RNTI. The RNTI may be at least one of a P-RNTI, a C-RNTI, or an RP-RNTI. The paging PDCCH may include a paging PCH configuration and also an UL-SCH configuration and a connection request indicator (or connection resumption request indicator). The UL-SCH configuration resource may be allocated a subframe or TTI later in time than a paging message transmission resource allocated by the paging PCH configuration. The UL-SCH resource may be allocated more than 3 TTIs later than the paging message transmission resource.

In operation 1t-10, a base station transmits a paging message to a terminal. The paging message may include a terminal identifier, which may include at least one of an IMSI, S-TMSI, C-RNTI, and RP-TMSI.

In operation 1t-15, the terminal receives paging information through the paging PCH and checks whether the received information contains its own terminal identifier.

If the terminal identifier does not exist, the terminal proceeds to operation 1t-20. In operation 1t-20, the terminal performs a sleep operation until the next paging occasion.

If there is its own terminal identifier, the terminal proceeds to operation 1t-25. In operation 1t-25, if the reconnection request indicator is a predetermined value (typically 1), the terminal transmits an RRC connection resumption request through the UL-SCH. The UL-SCH transmission resource may use the UL-SCH resource allocated at operation 1 t-10.

In operation 1t-30, the base station transmits a Random Access Response (RAR) and an RRC connection recovery to the terminal. The terminal may receive the RAR through the PDSCH. If transmission and reception of the RRC connection restoration request and RRC connection restoration are successfully completed, the network and the terminal may recognize that the connectivity is completed and may perform a transition of the terminal state to RRC _ CONNECTED.

The method for allocating dedicated resources (time, frequency, code (preamble)) that can be used for the limited uplink access request to allow the corresponding terminal to perform fast network connection may be an RNTI + preamble transmission method.

Fig. 1U is a diagram illustrating transmission of an RNTI and a preamble.

When the UE-specific ID of the RNTI receiving terminal is included in the reception information, the RNTI receiving terminal starts the RACH using the dedicated preamble and indicates that the corresponding RACH is a RACH for an uplink reconnection request. The base station receiving the dedicated RACH preamble recognizes that the terminal performs a network reconnection request, thereby reconfiguring and restoring the connection.

Fig. 1V is a diagram illustrating a fast network reconnection method using a paging PCH configuration including a dedicated RACH preamble.

Referring to fig. 1V, a system includes a base station and a terminal. The terminal may be in a Light Connection (LC) state or in an inactive state.

In operation 1v-05, the base station transmits a paging PDCCH to the terminal using the RNTI. The RNTI may be at least one of a P-RNTI, a C-RNTI, or an RP-RNTI. The paging PDCCH may include a paging PCH configuration and also a dedicated RACH preamble.

In operation 1v-10, a base station transmits a paging message to a terminal. The paging message may include a terminal identifier, which may include at least one of an IMSI, S-TMSI, C-RNTI, and RP-TMSI.

In operation 1v-15, the terminal receives paging information through the paging PCH and checks whether the received information contains its own terminal identifier.

If the terminal identifier does not exist, the terminal proceeds to operation 1v-20. In operation 1v-20, the terminal performs a sleep operation until the next paging occasion.

If there is its own terminal identifier, the terminal proceeds to operation 1v-25. In operation 1v-25, the terminal initiates a RACH using a dedicated preamble, thereby indicating that the corresponding RACH is a RACH for an RRC connection recovery request.

The base station receiving the dedicated RACH preamble recognizes that the terminal performs a network reconnection request. Then, the base station resets and resumes the connection with the terminal in operation 1 v-30. The base station may send the RAR and the RRC connection recovery to the terminal. The terminal may receive RAR through PDSCH. If transmission and reception of the RRC connection recovery request and RRC connection recovery are successfully completed, the network and the terminal may recognize that the connectivity is completed and may perform transition of the terminal state to RRC _ CONNECTED.

A paging message + resource (time, frequency, code (preamble)) transmission method will now be described

Fig. 1W is a diagram illustrating transmission of a paging message and a preamble.

When its UE-specific ID is included in the reception information, a terminal receiving a corresponding paging message on the paging PCH starts RACH using a dedicated resource and indicates that the corresponding RACH is a RACH for uplink reconnection request. The base station receiving the dedicated RACH preamble recognizes that the terminal performs a network reconnection request, thereby reconfiguring and restoring the connection.

Fig. 1X is a diagram illustrating a fast network reconnection method using a paging message including a dedicated RACH preamble.

Referring to fig. 1X, a system includes a base station and a terminal. The terminal may be in a Light Connection (LC) state or in an inactive state.

In operation 1x-05, the base station transmits a paging PDCCH to the terminal using the RNTI. The RNTI may be at least one of a P-RNTI, a C-RNTI, or an RP-RNTI. The paging PDCCH may include a paging PCH configuration.

In operation 1x-10, a base station transmits a paging message to a terminal. The paging message may include a terminal identifier, which may include at least one of an IMSI, S-TMSI and C-RNTI, RP-TMSI. The paging message may include the dedicated preamble or the dedicated preamble together with the paging message.

In operation 1x-15, the terminal receives paging information through the paging PCH and checks whether the received information contains its own terminal identifier.

If the terminal identifier does not exist, the terminal proceeds to operation 1x-20. In operation 1x-20, the terminal performs a sleep operation until the next paging occasion.

If there is its own terminal identifier, the terminal proceeds to operation 1x-25. In operation 1x-25, the terminal initiates a RACH using a dedicated preamble, thereby indicating that the corresponding RACH is a RACH for an RRC connection recovery request.

The base station receiving the dedicated RACH preamble recognizes that the terminal performs a network reconnection request. Then, the base station resets and restores the connection with the terminal in operation 1 x-30. The base station may send the RAR and the RRC connection recovery to the terminal. The terminal may receive RAR through PDSCH. If transmission and reception of the RRC connection recovery request and RRC connection recovery are successfully completed, the network and the terminal may recognize that the connectivity is completed and may perform transition of the terminal state to RRC _ CONNECTED.

A direct transmission method of downlink data using RNTI will now be described.

In the case where it is desired to transmit a short message in downlink to a terminal operating in a power saving state, the network can identify the terminal by using a known C-RNTI (or other new RNTI) and allocate downlink resources to the terminal to transmit information.

In this case, if the terminal does not need to perform uplink synchronization through random access, the base station may allocate uplink ACK/NACK resources to downlink transmission, receive a response from the terminal, and perform retransmission and HARQ operations to improve the success rate (success rate) of DL transmission.

In this case, if the terminal needs to perform uplink synchronization through random access, the base station may repeatedly perform downlink transmission a certain number of times or more by using repetition to improve the success rate.

Fig. 1Y is a diagram illustrating a terminal according to an embodiment of the present disclosure.

Referring to fig. 1Y, the terminal may include a transceiver 1Y-10 for transmitting and receiving signals and a controller 1Y-30. The terminal may send and/or receive signals, information and messages through the transceivers 1 y-10. The controllers 1y-30 may control the overall operation of the terminal. The controller 1y-30 may include at least one processor. The controllers 1y-30 may control the operation of the terminal described with reference to fig. 1A to 1X.

The controllers 1y-30 may receive the beam feedback trigger condition and determine whether the beam feedback trigger condition is satisfied. If it is determined that the beam feedback trigger condition is satisfied, the controller 1y-30 may trigger beam feedback on a Medium Access Control (MAC) layer of the terminal and control transmission of a MAC control element (MAC CE) including beam feedback information based on the beam feedback trigger. The beam feedback trigger condition may include a case where a channel measurement value of at least one beam is greater than a sum of a predetermined threshold value and a channel measurement value of a current serving beam.

In addition, if the uplink of the terminal is synchronous, the controller 1y-30 may control transmission of beam feedback information by using uplink allocation resources received through a Scheduling Request (SR) procedure. The terminal may transmit the SR and receive information on resources allocated for beam feedback in response to the SR transmission. The resource allocation may be performed periodically or aperiodically.

If the uplink of the terminal is not synchronized, the controllers 1y-30 may control the transmission of the beam feedback information through a random access procedure. When beam feedback is triggered, the controller 1y-30 may control: the method includes transmitting a random access preamble, receiving a random access response in response to the transmission of the random access preamble, transmitting beam feedback information in response to the reception of the random access, and receiving a random access contention result in response to the transmission of the beam feedback information. The message transmitting the beam feedback information may be message 3 (MSG 3) in the random access procedure.

In addition, the controller 1y-30 may control reception of the beam change instruction information, and control the change of the beam based on the beam feedback information after a predetermined time when the beam change instruction information is received.

Fig. 1Z is a diagram illustrating a base station according to an embodiment of the present disclosure.

Referring to fig. 1Z, a base station may include transceivers 1Z-10 for transmitting and receiving signals and a controller 1Z-30. The base station may send and/or receive signals and information, messages, through the transceivers 1 z-10. The controllers 1z-30 may control the overall operation of the base station. The controller 1z-30 may include at least one processor. The controllers 1z-30 may control the operation of the base stations described with reference to fig. 1A to 1X.

In addition, the controller 1z-30 may control transmission of the beam feedback trigger condition to the terminal and also control reception of the MAC CE including the beam feedback information from the terminal. The beam feedback information may be triggered when it is determined that the beam feedback condition is satisfied at the MAC layer of the terminal. That is, the beam feedback condition may be triggered according to the determination of the MAC layer of the terminal. The beam feedback trigger condition may include a case where a channel measurement value of at least one beam is greater than a sum of a predetermined threshold and a channel measurement value of a current serving beam.

If the uplink of the terminal is synchronized, the controller 1z-30 may allocate uplink resources to the terminal through an SR process and control reception of beam feedback information from the allocated uplink resources.

In addition, if the uplink of the terminal is not synchronized, the controller 1z-30 may control reception of the beam feedback information through a random access procedure. The controller 1z-30 can control: the method includes receiving a random access preamble, transmitting a random access response in response to the reception of the random access preamble, receiving beam feedback information in response to the transmission of the random access response, and transmitting a random access contention result in response to the reception of the beam feedback information. The message to receive the beam feedback information may be MSG3 in a random access procedure.

Further, the controller 1z-30 may control transmission of the beam change indication information in response to reception of the beam feedback information and then control change of the beam based on the beam feedback information after a predetermined time.

Example B: beam grouping ]

According to an embodiment of the present disclosure, there may be provided a beam management method for a terminal and a base station, including the operations of: the method includes transmitting beam measurement information to a base station at a terminal, selecting a beam to be used based on the beam measurement information of the terminal at the base station, notifying information on the selected beam to the terminal at the base station, and changing a currently used beam to a new beam at the base station and the terminal.

In addition, according to an embodiment of the present disclosure, a method may be provided, by which a terminal inserts an indicator in beam measurement information to be transmitted to a base station to indicate whether a beam change message needs to be transmitted when the base station changes a beam. In addition, a beam change method of the base station using the indicator may be provided.

The wireless communication system considers the following structure: in which a single base station including a plurality of transmitting/receiving ends supports a wide physical area in order to improve delay due to frequent information exchange and achieve efficient resource utilization.

A Distributed Antenna System (DAS) transmits or receives the same signal by implementing different transmitting/receiving ends as physical antennas under a single base station.

A Remote Radio Head (RRH) system can transmit or receive different signals by implementing different transmitting/receiving ends under a single base station as a structure including an antenna and a simple Radio Frequency (RF) end.

A coordinated multipoint transmission/reception (CoMP) system is the following system: wherein, different transmitting/receiving ends under one or more base stations simultaneously transmit or receive the same synchronous information to or from one user, or when one transmitting/receiving end transmits or receives the information, other transmitting/receiving ends are silent.

Analog beamforming is used to form a beam having physical directivity in a specific direction, and antenna gain is obtained by transmitting different transmission power and phase using a plurality of array antennas and superimposing radiation patterns (radiation patterns) of the antennas.

Analog beamforming can set beams from multiple antennas in a desired direction without channel information of a target receiving end and allow transmission/reception in only one direction at a time (radiation patterns in other directions are shifted) to form beams that reach farther away with the same power and have high antenna gain (different beam widths/lengths according to the number of antennas).

Digital beamforming is the following technique: multiple orthogonal beams that offset the desired inter-channel interference are formed by applying different codes to each set of information before transmission for each antenna using multi-channel information between antennas having different strengths in a multi-antenna transmission/reception environment.

Digital beamforming exploits as many different channel characteristics as possible by using a precoding technique on the data transmitted through each antenna.

In addition, digital beamforming supports single-user MIMO and multi-user MIMO.

Hybrid beamforming is a technique that uses both analog and digital beamforming.

Hybrid beamforming uses digital beamforming using different precoding techniques for respective transmit antennas and beams formed by analog beamforming.

The techniques described in embodiments of the present disclosure may use one of analog beamforming, digital beamforming, and hybrid beamforming. In addition, a method of occupying and transmitting resources that can be physically or employing frequency, time, code, or signal distinguishing for information transmission is called beamforming, and is applicable to all systems in which the occupied resources are called beams.

In addition, features of the related art used in the wireless communication technology conforming to the 3GPP standard are as follows.

The uplink transmission (from the terminal to the base station) should be performed using the reserved resources through resource allocation of the base station.

A terminal requiring uplink transmission should be allocated resources for uplink transmission by transmitting a resource allocation request (i.e., SR) previously allocated by the base station. The terminal transmits an SR and then transmits a Buffer Status Report (BSR) to inform the amount of data to be transmitted in uplink, receives resource allocation, and performs uplink transmission. Alternatively, the terminal may perform uplink transmission through a Random Access Channel (RACH) capable of contention-based transmission.

The channel measurement information feedback includes a technique for notifying the base station of channel information measured by the terminal and channel measurement and feedback performed on the physical layer. Examples of such information include Reference Signal Received Power (RSRP), reference Signal Received Quality (RSRQ), signal-to-noise ratio (SNR), signal-to-interference-plus-noise ratio (SINR), channel Quality Indicator (CQI), and channel state information reference signal (CSI-RS). The terminal may acquire such information by measuring a specific signal (cell-specific reference signal or Common Reference Signal (CRS), dedicated Reference Signal (DRS), CSI-RS, or demodulation reference signal (DMRS)) transmitted by the base station.

The terminal may transmit the acquired information by using resources allocated by the base station according to the uplink transmission rule. Without the resources allocated by the base station, the wireless communication technology has no way or need to provide such information to the base station.

To improve efficiency, the wireless communication system transmits signals for maintaining connectivity, such as control signals and reference signals, by using frequency channels and time resources that can be commonly received by all users.

On the other hand, in the case of a multi-antenna beamforming system in which different resources such as frequency channels, time, beams, and codes are allocated and used differently for different beams, the resources may not be used due to a change in beam characteristics (i.e., directions or channels) caused between a resource reservation time and a use time.

For example, in a system using a plurality of analog beams for transmission/reception, a terminal and a base station transmit and receive information by selecting a specific beam that is estimated to be good. At this time, the base station reserves the best (or least problem-free) beam resource known at the time of reserving the resource for uplink transmission of the terminal. However, a change in the channel of the reserved beam resource may occur due to terminal movement or other variables, such as a sudden traffic (traffic) obstruction or climate change. This problem cannot be solved with the prior art when uplink information transmission fails due to a change in the characteristics of the reserved beam resources.

Accordingly, in the case of a multi-antenna beamforming system in which different resources, such as frequency channels, time, beams, and codes, are allocated and used differently for different beams, a beam management technique for exchanging beam state information between a terminal and a base station and for rapidly tracking and applying beam changes is required.

In addition, in the case of the related art that transmits signals for maintaining connectivity (such as control signals and reference signals) by using frequency channels and time resources that can be commonly received by all users, if a channel state deteriorates, there is only the following method: a method of changing a channel to another channel of a different frequency or attempting to reconnect to a network after a failure is declared when a radio link failure (radio link failure) condition is satisfied.

However, in the case of a multi-antenna beamforming system in which different resources such as frequency channels, time, beams, and codes are allocated and used differently for different beams, it is likely that another available beam exists at the same location despite deterioration in beam characteristics. Accordingly, since a terminal has an opportunity to maintain connectivity, a technology that can utilize it is required.

In general, a terminal informs a base station of a channel state change through channel information feedback allowed only on a physical layer. Specifically, the terminal may know a channel state by receiving a specific signal (CRS, DRS, RS, beam RS, or CSI-RS) from the base station, process and encapsulate the channel state information as feedback information (e.g., CQI, rank Indicator (RI), or Precoding Matrix Indicator (PMI)) and transmit it to the base station through a resource (e.g., physical Uplink Control Channel (PUCCH) or Physical Uplink Shared Channel (PUSCH)) allocated by the base station, which is capable of uplink transmission; or the terminal may send an uplink transmission request (or request resource allocation for uplink transmission) to the base station, receive the resource allocation, and send channel state information.

However, in the case of a multi-antenna beamforming system in which different resources such as frequency channels, time, beams, and codes are allocated and used differently for different beams, if the performance of unique resources (e.g., analog beams or mixed beams) has been used by a terminal and a base station, a new procedure is required to inform the base station of other available resources and then use the corresponding resources allocated later.

Fig. 2A is a diagram illustrating a multi-beam system according to an embodiment of the present disclosure.

Referring to fig. 2A, the system includes a base station and a terminal that form analog beams having various directions. Here, the analog beam used by the base station and the terminal may be composed of a plurality of small antenna arrays, and wireless transmission/reception may be performed in one direction by using one antenna array group at a time. If one or more antenna array sets are simultaneously operable, wireless transmission/reception may be performed in one or more directions at a time.

Embodiments of the present disclosure provide the following environments: in a multi-antenna beamforming system in which different resources such as frequency channels, time, beams, and codes are allocated and used differently for different beams, a base station (or transmission/reception end) and a terminal transmit/receive using one or more beams using a pair of beams at a time.

In addition, a beam information exchange method suitable for a case where a base station or a terminal does not use a plurality of beams is provided, such as a case where a base station uses one beam and a terminal uses one beam or a case where a base station uses one beam and a terminal uses one or more beams.

Specifically, the terminal finds and uses an appropriate beam by exchanging and changing information on a beam used in measuring beam information at the same base station, providing beam information, and changing the beam being used. In a multi-antenna beamforming system in which different resources, such as frequency channels, time, beams, and codes, are differently allocated and used for different beams, a base station and a terminal should be able to detect and track channel states of transmission/reception beams in real time and maintain and change used (used) beams.

Beam measurements are performed to measure the channels of beam pairs resulting from various combinations of beams between the terminal and neighboring base stations. The beam measurement may be performed periodically or aperiodically by the terminal or the base station.

Embodiments of the present disclosure are not limited by any beam measurement method, and assume that a terminal or a base station can measure channel states of beams paired with each other. It is also assumed that the terminal performs an operation of measuring beam information in a specific manner, and performs an operation of updating and identifying a measurement value according to each beam information measurement.

The beam feedback is an operation of notifying the base station of beam information measured by the terminal. Feedback from the terminal (or base station) is necessary because the base station (or terminal) as the transmitting end cannot know downlink (or uplink) beam information. The beam information feedback may be performed periodically or aperiodically by the terminal or the base station.

Embodiments of the present disclosure provide an operation of transmitting beam information measured by a terminal to a base station. However, the scope of the present disclosure is not limited to beam feedback or reporting of the terminal, and an operation of transmitting beam information measured by the base station to the terminal is also possible. Accordingly, the following procedures for beam feedback and beam change of the terminal may be equally or similarly applied to the operation of the base station.

In an embodiment of the present disclosure, the beam feedback information may be Beam State Information (BSI) and/or Beam Refinement Information (BRI).

To perform beam change, the base station or the terminal may determine a beam pair to be used in the future based on the received beam feedback information. The base station or the terminal may perform various operations to use the determined beam pair.

The terminal refers to a beam measurement entity that performs beam measurement, and the base station refers to a beam use entity that transmits a reference signal for beam measurement, allocates resources for the beam measurement entity, and uses beam information through measurement when the beam measurement entity notifies the beam information through feedback.

Although the terminal and the base station serve as an entity performing beam measurement and feedback and an entity transmitting a beam reference signal and allocating resources, respectively, their roles are not limited thereto. Alternatively, the base station may be an entity that performs beam measurement and feedback, and the terminal may be an entity that transmits a beam reference signal and allocates resources.

The best beam refers to a beam pair or two beams of the beam pair when one beam of the beam measurement entity and one beam of the beam usage entity are determined to be assumed to have the best performance among the analog beams available by the beam measurement entity and the beam usage entity. Additionally, the best beam may generally be, but is not limited to: in the best beam pair measured according to the reference signal transmitted by the beam using entity, the best performance beam used by the beam using entity (base station) to communicate with the beam measuring entity (terminal).

The beam measuring entity may inform the beam using entity about the best beam pair by feedback, or the beam using entity may inform the corresponding beam measuring entity about only one beam to be used. For example, the terminal may notify the base station of information on only one beam belonging to the base station to be used for transmission/reception of information.

Fig. 2B is a diagram illustrating a frame structure for feeding back multi-beam IDs and beam measurement values according to an embodiment of the present disclosure.

Referring to fig. 2B, an embodiment of a MAC-CE structure for transmitting N-beam information (ID 9 bits, BRSRP 7 bits) is shown. BI (9 bits) is a field indicating a beam index. BRSRP (7 bits) is a field indicating RSRP of a beam.

Although fig. 2B shows 9-bit BI and 7-bit BRSRP, the fields may have different bit sizes.

Fig. 2C is a diagram illustrating a frame structure for feeding back multi-beam IDs and beam measurements according to an embodiment of the present disclosure.

Referring to fig. 2C, a MAC-CE structure for transmitting N beam information (eNB beam ID 3 bits, BRSRP 7 bits) is shown. An RBI (3 bits) is a field indicating a beam index. RB-RSRP (7 bits) is a field indicating received RSRP of a beam. R is a reserved bit set to "0".

Although fig. 2C shows a 9-bit RBI and a 7-bit RB-RSRP, the fields may have different bit sizes.

Fig. 2D is a diagram illustrating a frame structure for feeding back multi-beam IDs and beam measurements according to an embodiment of the present disclosure.

Referring to fig. 2D, a MAC-CE structure for transmitting N beam information (eNB ID 9 bits, UE ID 5 bits, BRSRP 7 bits) is shown. BI _1 (9 bits) is a field indicating a beam index of the base station. BI _2 (9 bits) is a field indicating a beam index of the terminal. BRSRP (7 bits) is a field indicating RSRP of a beam.

In an embodiment of the present disclosure, a method for improving efficiency of exchanging information with a base station while minimizing information transmitted by a terminal to the base station is proposed.

A method for adding an indicator to request transmission of beam change information will now be discussed.

Fig. 2E is a diagram illustrating beam change by beam feedback, and fig. 2F and 2G are diagrams illustrating a frame structure for transmitting beam feedback.

The terminal has channel/link measurement values for each base station transmit beam and terminal receive beam through the observed and measured information. Based on these channel measurements, the terminal feeds back measurements of the top-rank (top-rank) or best beam of the base station and its beam ID information. When the terminal provides the base station with only information about the beam of the base station, and when the base station receiving the information uses a specific beam, the terminal does not have information about which beam is used. In other words, if the base station desires to change a currently used beam to a new beam when receiving beam feedback information, the base station should inform the terminal to which beam the beam is to be changed. Then, the base station and the terminal should wait until a designated time and then change beams.

When the beam change request message is a Beam Change Indication (BCI) message, an example of a corresponding operation procedure is shown in fig. 2E.

As shown in fig. 2E, when only beam information of the base station is fed back without beam information of the terminal, a beam change request message is transmitted/received at every beam change, and the beam is changed by waiting until a designated time. However, if the base station beam needs to be changed but the terminal does not need to change the beam, latency for transmitting the beam change request message and changing the beam is wasted.

In a system environment in which multipath and separated (separated) transmission reception points are considered, a terminal can receive multiple beams of the same cell by using one Rx beam. In this case, if Rx beam information of the corresponding terminal is not included in beam measurement information fed back to the base station, it is impossible to distinguish a case where it is not necessary to transmit a BCI message as described above. Thus, the network may send a BCI message each time and perform a beam change after a certain time.

To eliminate such waste, the present disclosure proposes a method of transmitting beam feedback by adding a 1-bit indicator to beam information of a base station, as shown in fig. 2F and 2G.

Fig. 2F and 2G illustrate structures for transmitting base station beam feedback with a 1-bit indicator added according to an embodiment of the present disclosure.

The indicator may provide terminal beam information to the base station and be used in the following manner.

When the base station changes the used beam to a corresponding beam, an indicator is set to indicate that a beam change request message must be transmitted to the terminal. The terminal can manage the measured beam pair information according to table 17.

Table 17 is a beam pair measurement information management table of the terminal.

TABLE 17

Cell (or gNB, TRP) Tx beam ID	UE Rx Beam ID	Beam quality (RSRP)
			1	1	RSRP _1,1
1	2	RSRP _1,2
			…	…	…
1	NRx	RSRP				_{1,N_Rx}
			2	1	RSRP _2,1
2	2	RSRP _2,2
			…	…	…
2	NRx	RSRP _{2,N_Rx}
			…	…	…
NTx	NRx	RSRP _{N_Tx,N_Rx}

The terminal generates beam feedback information to be transmitted to the network in descending order of beam pairs having the best performance (i.e., best quality, best RSRP, RSRQ, CQI, SNR, or SINR).

Table 18 is an example of K-beam pair measurement information feedback for the terminal.

Watch 18

Cell (or gNB, TRP) Tx beam ID	UE Rx Beam ID	Beam quality (RSRP)
			2	1	RSRP _2,1
4	4	RSRP _4,4
			…	…	…
1	1	RSRP _1,1

The indicator is set to 0 if the UE Rx beam ID of the beam measurement information feedback table is equal to the currently used serving beam ID (last beam ID), and is set to 1 otherwise.

Alternatively, the same indicator may be allocated if the UE Rx beam ID of the beam measurement information feedback table is for Rx beams that may be simultaneously received by the terminal, and a different indicator may be allocated if the UE Rx beam ID is for Rx beams that may not be simultaneously received.

Table 19 shows an example in which an indicator is included in the K beam pair measurement information feedback of the terminal when the serving beam ID currently used by the terminal is 1.

Watch 19

The UE Rx beam ID is removed from the above information to complete the beam feedback information.

Table 20 shows an example of K-beam pair measurement information feedback of the terminal when the serving beam ID currently used by the terminal is 1.

Watch 20

Fig. 2H is a diagram illustrating operations of a base station and a terminal for changing a currently used base station beam to a base station beam having an on indicator according to an embodiment of the present disclosure.

In this case, the corresponding indicator of on (1) indicates that the terminal should perform communication using a terminal beam different from the currently used terminal beam.

At this time, when the currently used base station beam is changed to the base station beam having the indicator of off (0), the base station may arbitrarily change the beam without providing any information to the terminal. In this case, time consumption such as committing and waiting for BCI message transmission and beam change is reduced, and thus efficient and rapid beam change becomes possible.

In various embodiments of the present disclosure, the

values

0 and 1 of the indicator may also be applied inversely, and the indicator is not limited to 1-bit information.

In addition, if the indicators are the same value, it may be indicated that the terminal can simultaneously receive the base station beams. In this case, the indicator may indicate that the terminal may employ the same Rx beam (or simultaneously receivable and available Rx beams) to simultaneously receive the base station beam indicated by the corresponding indicator. In this case, the base station may perform transmission to the terminal using two or more base station beams simultaneously indicated by the indicator.

Referring to fig. 2H, in operation 2H-05, the terminal transmits beam measurement report information to the base station. The terminal may measure channel quality between a terminal reception beam and a base station transmission beam and generate beam measurement report information. The beam measurement report information may include information described in tables 17 to 20. In addition, the beam measurement report information may include a base station transmission beam ID, beam RSRP, RSRQ, CQI, SNR, SINR, and an indicator.

In operation 2h-10, the base station changes the currently used beam of the terminal. The base station may change the beam based on the beam measurement report information received from the terminal.

In operation 2h-15, the base station identifies an indicator included in the beam measurement report information. The base station may determine whether it is necessary to transmit the BCI message based on the indicator, or may determine whether it is necessary to wait for a certain time while the beam is changed. For example, it may be checked whether the indicator of the beam to be changed is 1. If the indicator is 0, operations 2h-20 are performed. If the indicator is 1, operations 2h-25 are performed. The base station may identify the beam pair having the indicator 0 as one group and also identify the beam pair having the indicator 1 as one group.

If the indicator is 0, the base station changes the beam without transmitting the BCI message to the terminal at operation 2h-20. Indicator 0 may indicate a base station transmission beam that may be received with the current reception beam of the terminal.

If the indicator is 1, the base station transmits a BCI message to the terminal in operation 2h-25. The BCI message may include identification information (e.g., beam ID) of the beam that the base station wishes to change. Indicator 1 may indicate a base station transmission beam that may not be received with the current reception beam of the terminal. In this case, when the base station changes to the corresponding transmission beam, the terminal needs to change the reception beam.

In operation 2h-30, the base station waits for a given time (or a specific TTI, subframe) after the transmission of the BCI message and then uses a new beam. In operations 2h-35, the terminal waits for a given time (or a specific TTI, subframe) after the BCI message reception and then uses a new beam. The base station may use the changed transmission beam, and the terminal may use the changed reception beam.

The base station may transmit downlink information by using the changed transmission beam, and the terminal may receive downlink information transmitted by the base station by using the changed reception beam or the current reception beam when the reception beam change is not required.

In the case of changing to a beam having an indicator other than 1, BCI message transmission and waiting time may be omitted, thereby reducing delay.

In addition, the indicator may indicate base station beams that the terminal may receive simultaneously. In this case, it may indicate that the terminal may use the same Rx beam(s) to simultaneously receive the base station beams indicated by the corresponding indicators. In this case, the base station may perform transmission to the terminal using two or more base station beams simultaneously indicated by the indicator.

When the base station changes the used beam to the corresponding beam, an indicator indicating that the beam can be freely changed at any time without any special message is provided.

Fig. 2I is a diagram illustrating operations of a base station and a terminal in a case where an indicator specifies that the base station can freely change without transmitting BCI to the terminal according to an embodiment of the present disclosure.

In contrast to fig. 2H, the indicator in fig. 2I may indicate that the base station may freely change without sending a BCI message to the terminal.

The base station transmission beam with the indicator of 0 may be simultaneously used at the determination of the base station and used for MIMO transmission to the terminal.

Referring to fig. 2I, in operation 2I-05, the terminal transmits beam measurement report information to the base station. The terminal may measure the channel quality between the terminal receive beam and the base station transmit beam and then generate a beam measurement report. The beam measurement report may include information described in tables 17 to 20. In addition, the beam measurement report is not limited thereto, and may include one of beam pair measurement information feedbacks. For example, it may include a transmission beam ID, beam RSRP, RSRQ, CQI, SNR, SINR, and indicator of the base station. The indicator may indicate that the base station may freely change without sending a BCI message to the terminal.

In operation 2i-10, the base station determines to change a currently used beam of the terminal. The base station may determine whether to change the beam based on the beam measurement report received from the terminal.

In operations 2i-15, the base station identifies an indicator included in the beam measurement report. The base station may determine whether it is necessary to transmit the BCI message based on the indicator, or may determine whether it is necessary to wait for a certain time while the beam is changed. For example, it may be checked whether the indicator of the beam to be changed is 1 or 0. If the indicator is 0, operations 2i-20 are performed. If the indicator is 1, operations 2i-25 are performed. The base station may identify the beam pair having the indicator 0 as one group and also identify the beam pair having the indicator 1 as one group.

If the indicator is 0, the base station changes the beam without transmitting the BCI message to the terminal at operation 2i-20. Indicator 0 may indicate a base station transmission beam that may be received with the current reception beam of the terminal.

If the indicator is 1, the base station transmits a BCI message to the terminal in operation 2i-25. The BCI message may include identification information (e.g., beam ID) of the beam that the base station wishes to change. Indicator 1 may indicate a base station transmission beam that is not receivable with the current reception beam of the terminal. In this case, when the base station changes to a corresponding transmission beam, the terminal needs to change a reception beam.

In operation 2i-30, the base station waits for a given time (or a specific TTI, subframe) after BCI message transmission and then uses a new beam. In operations 2i-35, the terminal waits for a given time (or a specific TTI, subframe) after the BCI message reception and then uses a new beam. The base station uses the changed transmission beam, and the terminal may use the changed reception beam.

Even if the base station simultaneously uses the transmission beams, the indicator may indicate that the terminal can simultaneously receive information of the same time.

When the indicator indicates that the terminal can simultaneously receive information, the indicator may indicate that the terminal can simultaneously receive the base station beam indicated by the corresponding indicator using the same Rx beam(s). In this case, the base station may simultaneously perform simultaneous transmission to the terminal using two or more base station beams indicated by the corresponding indicators.

In addition, the indicator need not be 1 bit, and the same value indicator may indicate a plurality of beams that can be simultaneously transmitted.

In addition, the indicator may be used as any arbitrary beam group ID set by the terminal. In this case, the base station may recognize that the terminal divides the base station beams into groups, identify different groups, and instruct specific operations (e.g., beam measurement and reporting).

If the terminal can operate one Rx beam at a time and if beam transmissions of different base stations can be received simultaneously using the corresponding Rx beam, a method for generating feedback information including a beam indication of the terminal is as follows.

Table 21 is a beam pair measurement information management table of the terminal.

TABLE 21

Table 22 is an example of K-beam pair measurement information feedback of the terminal.

TABLE 22

Cell (or gNB, TRP) Tx beam ID	UE Rx Beam ID	Beam quality (RSRP)
			2	1	RSRP _2,1
4	4	RSRP _4,4
			3	4	RSRP3 _,4
6	5	RSRP _6,5
			…	…	…
1	1	RSRP _2,1

Table 22 is a table in which measurement information grouped into pairs of base station Tx beams and terminal Rx beams is arranged in performance order. For example, in table 22, the channel performance (RSRP) of the second base station Tx beam and the first terminal Rx beam is optimal, while the channel performance (RSRP) of the fourth base station Tx beam and the fourth terminal Rx beam is sub-optimal.

After the sorting is completed according to the signal strength of the received beam pairs, the terminal may allocate an indicator by grouping simultaneously receivable beam pairs having the same indicator.

Table 23a is a table for allocating indicators by grouping the simultaneously receivable beams in the order of performance.

TABLE 23a

Cell (or gNB, TRP) Tx beam ID	UE Rx Beam ID	Indicator (I)	Beam quality (RSRP)
				2	1	0	RSRP _2,1
4	4	1	RSRP _4,4
				3	4	1	RSRP _3,4
6	5	2	RSRP _6,5
				…	…	…	…
1	1	0	RSRP _2,1

In table 23a, the terminal assigns groups in the order of the same Rx beam ID, distinguishes base station-terminal beam pairs belonging to the corresponding group and assigns them to the same indicator.

In table 23a, the terminal assigns indicator 0 to the group to which the best base station-terminal beam pair belongs, and then assigns new group indicator 1 to the next best base station-terminal beam pair. Since the third best base station-terminal beam pair has the same Rx beam as the second best base station-terminal beam pair and can receive at the same time, it is assigned the same group indicator 1 as the second best base station-terminal beam pair. With this rule, the terminal can sequentially group information for base station-terminal beam pairs to be transmitted to the network.

Here, the terminal Rx beam ID train may be removed from information actually fed back to the base station by the terminal. Of course, another case including the terminal Rx beam ID is also considered.

Table 23b is a table for allocating indicators by grouping beams that can be received at the same time in the order in which the beams are received by the terminal.

TABLE 23b

Cell (or gNB, TRP) Tx beam ID	UE Rx Beam ID	Indicator symbol	Beam quality (RSRP)
				2	1	1	RSRP _2,1
4	4	4	RSRP _4,4
				3	4	4	RSRP _3,4
6	5	5	RSRP _6,5
				…	…	…	…
1	1	1	RSRP _2,1

In table 23b, the terminal assigns groups in the order of the same Rx beam ID, distinguishes base station-terminal beam pairs belonging to the corresponding group and assigns them to the same indicator.

In table 23b, the terminal allocates an indicator of each beam pair group by using its Rx beam ID. For example, in the case of a base station-terminal beam pair having a terminal Rx beam ID of 4, this indicator is also assigned 4. The method has a disadvantage in that the number of bits for indicator transmission should be secured according to the number of Rx beams of the terminal regardless of the amount of beam information transmitted by the terminal in feedback. For example, if a specific terminal has 12 Rx beams and transmits only 4 beam measurement information at a time, the number of bits in the signal for the indicator should be 4 bits, so that the number of bits in the signal may be a maximum of 12.

Here, the terminal Rx beam ID column may be removed from information actually fed back to the base station by the terminal. Of course, other scenarios including the terminal Rx beam ID are also contemplated.

Table 23c is a table for constructing feedback transmission by grouping receivable beams having the same number.

TABLE 23c

Cell (or gNB, TRP) Tx beam ID	UE Rx Beam ID	Indicator (I)	Beam quality (RSRP)
				2	1	0	RSRP _2,1
1	1	0	RSRP _1,1
				4	4	1	RSRP _4,4
3	4	1	RSRP _3,4
				6	5	2	RSRP _6,5
5	5	2	RSRP _5,5
				…	…	…	…

In table 23c, the terminal assigns group indicators to beam pairs having the same Rx beam ID in order of performance in the same manner as in table 23a, and then reconstructs a group to contain information on the same number of beam pairs.

Although the group indicators of the terminals are allocated in order of performance, the table 23c allocates the group indicators as in the table 23b (or using any other method), and then rearranges the number of beam pairs belonging to the corresponding group and to be fed back to the base station into the same 2.

If the same number of beam information sets are included in each group and provided to the network, the network may deliver the number of beam pairs to be transmitted by the terminal for each group to the terminal through a downlink signal.

For example, as shown in table 23c, a base station that wishes to receive information on two beam pairs per group may deliver the number of beam pairs per group to a terminal by using one of the following methods.

The total number of beam pairs to be reported in the Radio Resource Management (RRM) measurement report configuration signal, the number of beam pairs to be reported per group, and the number of groups to be reported may be transmitted. In this case, the terminal transmits an RRM measurement report which is uplink-transmitted according to the condition to include the group and the number of beam pairs to be reported per group. For example, if the total number of beam pairs to be reported is K, the number of beam pairs to be reported per group is L and the number of groups to be reported is M, the terminal may report in the following manner.

If K > L M, the terminal provides a total of L M beam pair information to the network through L for M groups.

If K < L M, the terminal arranges the beam pairs in the performance order of the corresponding beam pairs and provides information to the network by constructing a report signal such that each group includes a maximum of L beams within a range not exceeding a maximum of M beam groups, and thus the total number of beam pairs is K.

If L =0 and M =0, or if L = ∞ and M = ∞ the terminal does not care about the number of beams per beam group and provides information to the network by constructing a report signal so that the beam pairs become K in order or performance as in tables 23a and 23 b.

The beam measurement information provided by the terminal may include information on: the base station transmits a beam ID, a terminal reception beam ID, a beam measurement amount, RSRP, RSRQ, SNR, SINR, CQI, and a group indicator.

It is possible to send: the total number of beam pairs reported in the downlink physical layer control signal (DCI on PDCCH) or MAC-CE signal, the number of beam pairs to report per group, and the number of groups to report. In this case, the terminal transmits an uplink control signal (UCI on PUCCH), an uplink data signal (data on PUSCH), or an uplink MAC-CE which is uplink-transmitted according to conditions to include groups and the number of beam pairs to be reported per group. For example, if the total number of beam pairs to be reported is K, the number of beam pairs to be reported per group is L, and the number of groups to be reported is M, the terminal may report in the following manner.

On the other hand, the terminal Rx beam ID sequence may be removed from the information actually fed back to the base station by the terminal. Of course, another case including the terminal Rx beam ID is also considered.

A method for adding an indicator to request transmission of beam change information of a terminal capable of simultaneously using a plurality of Rx beams will now be described.

The terminal has channel/link measurement values for Tx beam of each base station and Rx beam pair of the terminal through the observed and measured information.

Based on these channel measurements, the terminal feeds back measurements of the top-level or best beam of the base station and its beam ID information, while adding an indicator.

In this method for providing beam feedback information to a base station with an indicator added, when a terminal can simultaneously operate two or more different Rx beams, the indicator and the beam feedback information may be configured in the following manner.

When a terminal needs to change to an Rx beam other than two or more Rx beams currently used for wireless communication, a method for transmitting beam feedback with an indicator denoted ON (1, true) is provided.

An indicator of Tx of the base station that can be received using the beam used by the terminal is denoted as 0 and transmitted. For the other beams, the indicator is denoted 1 and is transmitted.

Table 24 is a table including indicators in the K beam pair measurement information feedback of the terminal when the UE Rx beam IDs currently being used by the terminal are 1 and 2.

TABLE 24

Cell (or gNB, TRP) Tx beam ID	UE Rx Beam ID	Indicator symbol	Beam quality (RSRP)
				2	1	0	RSRP _2,1
4	4	1	RSRP _4,4
				3	2	0	RSRP _3,2
5	3	1	RSRP _5,3
				…	…	…	…
1	1	0	RSRP _1,1

When the UE Rx beam ID is removed from the above information, the beam feedback information is completed as follows.

Table 25 is a table including indicators in the completed beam feedback when the UE Rx beam IDs currently used by the terminal are 1 and 2.

TABLE 25

In order to change a beam from a base station currently in use with a corresponding indicator of on (1), the base station should change the beam through a process such as transmitting a BCI message to the terminal.

At this time, when the currently used base station beam is changed to the base station beam having the indicator of off (0), the base station may arbitrarily change the beam without providing any information to the terminal. In this case, time consumption such as commitment and waiting for BCI message transmission and beam change is reduced, and thus efficient and rapid beam change becomes possible.

In addition, the indicator may indicate base station beams that the terminal may receive simultaneously. In this case, it may indicate that the terminal may simultaneously receive the base station beams indicated by the corresponding indicators using the same Rx beams (or simultaneously receivable and available Rx beams). In this case, the base station may perform transmission to the terminal using two or more base station beams simultaneously indicated by the indicator.

A method of beam change/beam simultaneous use by an indicator of a base station will now be described.

The base station (eNB, gNB, or Transmission and Reception Point (TRP)) may select and change a beam to be used for communication with the terminal through information received as described above. At this time, in the case of using a beam having an indicator indicating that a BCI message for beam change needs to be transmitted, after performing beam change request message transmission and beam change procedures, the corresponding beam should be used.

On the other hand, in case of using a beam that does not need to transmit a BCI message for beam change, since the indicator indicates that the terminal can receive using the same Rx beam, the corresponding beam can be freely used without requiring the beam change request message transmission and the beam change procedure.

In addition, the indicator may indicate base station beams that the terminal may receive simultaneously. In this case, it may indicate that the terminal may simultaneously receive the base station beam indicated by the corresponding indicator using the same Rx beam(s). In this case, the base station may perform transmission to the terminal using two or more base station beams simultaneously indicated by the indicator.

A method for indicating when simultaneous reception is not possible using the indicator will now be described.

The indicator may indicate a base station beam that the terminal cannot receive simultaneously. In this case, the indicator may indicate that the terminal may not simultaneously receive the base station beam indicated by the corresponding indicator using the same Rx beam(s). The base station may perform transmission to the terminal using two or more base station beams included in different indicator sets.

If the terminal can use multiple Rx beams simultaneously, base station beams that cannot be used simultaneously can be grouped and indicated to obtain diversity gain using these different Rx beams based on the same Rx beam or to maximize diversity gain.

For example, referring to table 23a, the terminal indicates to the network information that can be received using the same Rx beam by grouping Tx beams of the network. In this case, if the terminal can simultaneously receive different Rx beams, beams that can be simultaneously transmitted using the information should be selected from base station beams belonging to different group indications rather than the same group indication. Thus, the terminal can simultaneously receive the base station beams by using different Rx beams.

A first beam feedback transmission scheme according to beam selection at an initial connection will now be described.

Fig. 2J is a diagram illustrating operations of a base station and a terminal according to a first beam feedback transmission method for selecting a beam to use at an initial connection according to an embodiment of the present disclosure.

Referring to fig. 2J, in order for the terminal to select an indicator to be included in the beam feedback, it is necessary to identify an Rx beam currently used. To this end, a first Rx beam is selected when the terminal is first connected to the network, and then an indicator in beam feedback to be transmitted is selected.

The terminal and the base station designate available beams by using a method other than beam feedback. The terminal selects a beam pair having the highest success rate by a pre (pre) beam measurement result and successfully performs random access by using the corresponding beam pair. The terminal performs random access in any manner and successfully receives RAR from the base station by using a specific beam. The terminal successfully receives the UE-specific message from the base station in any way.

When the terminal and the base station designate an available beam by using the beam feedback, the terminal transmits all indicators in the beam feedback indicating that a beam change message (e.g., 1) is required to be transmitted before the designated beam.

A transmission scheme including beam group information in a beam change indication of a base station will now be described.

If the terminal constructs beam group information and transmits it to the base station, the base station may select the following method when transmitting a beam change instruction for using a new beam to a corresponding terminal in the downlink.

The base station may select a method for transmitting a beam ID to be changed and a beam group ID to which a beam to be changed belongs.

The network may transmit the beam ID and the beam group ID to be changed to the terminal. For example, if the beam group ID is an ID indicating a beam group that can be simultaneously received by the terminal, and if the base station transmits such a beam group ID, the terminal knows the beam group ID and thus knows which Rx beam will be used to receive the base station transmission. In a multi-antenna transmission/reception structure in which one base station beam can be received with two or more terminal beams, since the same base station beam can belong to two or more different terminal beam groups, the operation of the terminal can be simplified when the base station indicates such beam classification to the receiving terminal by giving a clear message using a specific beam group. On the other hand, the base station has overhead to perform additional operations to identify and select such terminal groups. Considering battery operated terminals, this operation performed by the network rather than the terminal may increase the battery usage time of the terminal.

The network may transmit only the beam group ID without transmitting the beam ID to be changed to the terminal. For example, if the beam group ID is an ID indicating a beam group that can be simultaneously received by the terminal, and if the base station transmits such a beam group ID, the terminal knows the beam group ID and thus knows which Rx beam will be used to receive the base station transmission. The terminal only needs to successfully receive information from the base station and transmit its own information so that information can be given to only appropriately select a terminal beam. This method has the advantage of simplifying the operation of the terminal by giving a clear message to indicate the receiving terminal using a specific beam group. In addition, there is a base station that can use beams overlapping or variably at any time in a group.

After receiving the beam group ID, the terminal performs communication using a terminal Rx beam (or Rx beam) capable of receiving base station information transmitted together with the corresponding beam group ID. This operation may be the same as the beam change operation of fig. 2E, and a signal including a beam group ID instead of a beam ID only in downlink information to be transmitted for beam change may be transmitted.

According to embodiments of the present disclosure, a terminal may measure degradation of one or more beams in use and trigger a beam recovery procedure to recover one or more beams to another beam. A process for determining performance degradation of a beam in use is referred to as a beam failure detection process, and a condition for triggering a beam recovery process including the beam failure detection process may be implemented by the following method.

According to the beam failure detection method, a beam may be any beam used by the terminal and the base station (base station beam, terminal beam or such beam pair), or any beam group (set of beams) explicitly (or implicitly) used by the terminal and the base station.

In this case, the beam may be a physical antenna setting or may be a measurement unit of the terminal (e.g., a Synchronization Signal (SS) block, an SS burst, a set of SS bursts, a CSI-RS block, a CSI-RS burst, or a set of CSI-RS bursts).

The resource/RS configuration may be done by beam recovery transmission resource allocation (i.e., RACH time/frequency/sequence, or any dedicated/common resource). The information of the beam(s) to which the terminal compares with the condition 1 may be a beam ID, an RS position, a frequency, and a time. The terminal may require a value such as a threshold or an offset.

L1 detection may be performed. If the beam measured by the physical layer satisfies condition 1, it is determined that the beam is failed. The physical layer sends a corresponding indication to the upper layers for later operation. The upper layer initiates a beam recovery procedure after receiving the indication.

L2 detection may be performed with an L1 indication. If the beam measured by the physical layer satisfies condition 1, an indication is transmitted to an upper layer. The L2 layer receives one or more indications from the physical layer and if the receipt of the indications satisfies condition 2, the L2 layer determines a beam failure and/or a beam recovery trigger. The L2 layer initiates the beam recovery procedure.

L3 detection may be performed with an L1 indication. If the beam measured by the physical layer satisfies condition 1, an indication is transmitted to an upper layer. The L3 layer receives one or more indications from the physical layer and determines a beam failure and/or beam recovery trigger if the receipt of the indications satisfies condition 2. The L3 layer initiates the beam recovery procedure.

L2 detection may be performed with an L1 indication. If the beam measured by the physical layer satisfies condition 1, an indication is transmitted to an upper layer. If the terminal receives one or more indications from the physical layer, and if the reception of the indications satisfies condition 2, the terminal attempts UL beam feedback transmission using pre-allocated resources (L1 feedback and/or L2 feedback).

If condition 3 is satisfied, the L2 layer determines a beam failure and/or a beam recovery trigger. The L2 layer initiates the beam recovery procedure.

L3 detection may be performed with an L1 indication. If the beam measured by the physical layer satisfies condition 1, an indication is transmitted to an upper layer. If the terminal receives one or more indications from the physical layer and if the reception of the indications satisfies condition 2, the terminal attempts UL beam feedback transmission using pre-allocated resources (L1 feedback and/or L2 feedback and/or L3 report).

If condition 3 is satisfied, the L3 layer determines a beam failure and/or a beam recovery trigger. The L3 layer initiates the beam recovery process.

Condition 1 may be that the measurement value of the beam having the base station control channel measurable by the terminal < threshold 1.

Condition 1 may be an estimated DL signal reception error probability > N1%.

Condition 1 may be that the measurement of the beam is < threshold1 and any beam measurement > threshold 2.

Condition 1 may be that the measurement value of beam set 1 promised with the base station in advance (or configured from the base station) < threshold 1.

Condition 1 may be any condition created by a combination of the above conditions.

Condition 2 may be the same as condition 1 described above, or N2 consecutive times of receiving the indication (i.e., L1 OOS).

Condition 2 may be that the indication (i.e., L1 OOS) is received N3 or more times within a given time (timer 2).

Condition 2 may be any one beam measurement > threshold 2.

Condition 2 may be that the measurement value of a particular beam in beam group set 2 previously committed (or configured from) with the base station < threshold 2.

If any timer 1 triggered immediately after condition 1 is met expires, timer 1 may be a value set in the terminal embodiment in the following case: the case where the IS not received from L1 in timer 1, the case where the UL signal transmission IS not successfully performed in timer 1, or the case where condition 1 IS maintained in timer 1. In addition, timer 1 may be a value configured by the base station, timer 1 may be cancelled when receiving any indication (synchronization indicator) from the lower layer, timer 1 may be cancelled when receiving any indication (i.e., RLF trigger indication, RLF declaration indication) from the upper layer, or any condition created by a combination of the above conditions.

Condition 3 may be that the indication is received N4 times consecutively (i.e., L1 out of service (OOS)) or N5 or more times (i.e., L1 OOS) within a given time (timer 2).

Condition 3 may be any one beam measurement > threshold 3.

Condition 3 may be a measurement value < threshold3 for a particular beam in beam set 2 previously committed (or configured) with the base station.

If any timer 2 triggered immediately after condition 2 is met expires, timer 2 may be a value set in the terminal implementation, or timer 2 may be a value configured by the base station in the following cases: a case where IS cannot be received from L1 in timer 2, a case where UL signal transmission cannot be successfully performed in timer 2, or a case where condition 1 and/or condition 2 IS maintained in timer 2. Timer 2 may be a value configured by the base station, or timer 2 may be a time value greater than a specific threshold4, and may be a timer indicating the location of an uplink transmittable resource (PRACH or SR resource) arrived within a time period exceeding threshold4 or long. In addition, timer 2 may be cancelled when any indication (synchronization indicator) is received from the lower layer, timer 2 may be cancelled when any indication (i.e., RLF trigger indication, RLF declaration indication) is received from the upper layer, or any condition created by a combination of the above conditions is satisfied.

A beam recovery request signal transmission method will now be described. When the beam failure condition is satisfied, the terminal may perform a beam recovery operation. Specifically, the terminal may transmit an uplink beam recovery request signal for beam recovery. For this reason, if the beam failure condition 2 is satisfied, the terminal may immediately trigger the UL beam recovery request signal.

Fig. 2K illustrates a method associated with RLF operation by which the terminal attempts beam recovery request transmission when condition 2 is satisfied, according to an embodiment of the disclosure.

Referring to fig. 2K, if condition 2 is satisfied, the terminal immediately triggers uplink beam recovery request signal transmission to arrive within the latest time. At this time, if there is a large difference between the resources for uplink transmission and the trigger time, the terminal waits for a corresponding time and determines whether the trigger condition is satisfied or canceled.

In addition, the terminal continuously transmits an UL signal by using a pre-allocated uplink resource between the trigger time point and the actual transmission time point. At this time, if the measured value of the resource is less than a certain threshold (condition 1), uplink transmission may be attempted to be performed (beam recovery: uplink feedback using pre-allocated resources).

If the trigger condition 1 is cancelled (or if it is no longer satisfied), the terminal may cancel all ongoing procedures even if the triggered uplink Beam Recovery Request (BRR) signal transmission time has not yet arrived. For example, if the received signal strength of a particular beam is below a particular threshold such that transmission of the corresponding uplink BRR signal is triggered, and if the received signal strength of the corresponding beam is observed to be above the threshold again before the transmission time is reached, the transmission of the uplink BRR signal may be cancelled.

A trigger UL beam recovery request signal after the beam failure condition is satisfied and after condition 3 is satisfied may be provided.

Fig. 2L illustrates a method associated with RLF operation in which a terminal attempts beam recovery request transmission when a specific condition 2 is satisfied, according to an embodiment of the present disclosure. Fig. 2L is an example of performing operations that wait until PRACH arrives at the end of the fixed timer.

Referring to fig. 2L, the terminal sets a condition 3 (e.g., a timer) when the condition 2 is satisfied, and continuously transmits an UL signal by using pre-allocated uplink resources while waiting for the condition to be satisfied. At this time, even if the measured value of the resource is less than a certain threshold (condition 1), the uplink transmission may attempt to improve the success rate.

If the condition 3 is satisfied, the terminal immediately triggers transmission of an uplink beam recovery request signal to arrive within a minimum time.

At this time, if there is a difference between the time when the condition 3 is satisfied and the resource for performing the UL beam recovery request, the terminal may perform an operation to be performed when the condition 2 is satisfied (beam recovery: uplink feedback using pre-allocated resources), and may determine whether the condition 1 is cancelled.

If the corresponding trigger condition 1 is cancelled (or if it is no longer satisfied), the terminal can cancel all the processes that are in progress even if the condition 3 is not satisfied. For example, if the received signal strength of a particular beam is below a particular threshold such that transmission of the corresponding uplink BRR signal is triggered, and if the received signal strength of the corresponding beam is observed to be above the threshold again before the transmission time is reached, the transmission of the uplink BRR signal may be cancelled. If the trigger condition 1 is cancelled (or if it is no longer satisfied), the terminal may cancel all ongoing procedures even if the resource time to perform the UL beam recovery request transmission has not yet been reached.

In addition, if a Radio Link Failure (RLF) is performed first even if the condition 3 is not satisfied, or if the RLF is declared before the closest PRACH arrival time is reached even if the condition 3 is satisfied, the terminal may cancel all beam recovery operations and perform an operation according to the RLF.

Fig. 2M illustrates a method associated with RLF operation in which a terminal attempts beam recovery request transmission when a specific condition 2 is satisfied, according to an embodiment of the present disclosure.

Referring to fig. 2M, the following example is shown: wherein BRT is declared through

condition

1 or 2 and the terminal performs a beam recovery operation (i.e., uplink feedback using pre-allocated resources) until a specific condition 3 is satisfied (i.e., a fixed timer expires), and then, when the condition 3 is satisfied, performs a beam recovery operation (i.e., uplink feedback using pre-allocated resources) while attempting beam recovery using PRACH. In this case, beam recovery using the PRACH may be continuously performed when condition 1 is satisfied, attempting only for a corresponding timer with a specific timer _ br, or attempting until a continuous (or discontinuous) N _ max _ br failure occurs.

Fig. 2N illustrates a method associated with RLF operation by which a terminal attempts beam recovery request transmission when a specific condition 2 is satisfied, according to an embodiment of the present disclosure.

Fig. 2N is an example of: wherein BRT is declared through

condition

1 or 2, and the terminal performs a beam recovery operation (i.e., uplink feedback using pre-allocated resources) while attempting beam recovery using PRACH. In this case, beam recovery using the PRACH may be continuously performed when condition 1 is satisfied, attempting only for a corresponding timer with a specific timer _ br, or attempting until a continuous (or discontinuous) N _ max _ br failure occurs.

Fig. 2O illustrates a method associated with RLF operation in which a terminal attempts beam recovery request transmission when a specific condition 2 is satisfied, according to an embodiment of the present disclosure.

Referring to fig. 2O, the terminal sets a specific condition 3 (e.g., timer), waits for the condition to be satisfied, and transmits an UL signal by using a pre-allocated uplink resource (beam recovery). At this time, even if the measured value of the resource is less than a certain threshold (condition 1), the uplink transmission may attempt to improve the success rate.

The terminal may continue to perform the beam recovery operation until the PRACH arrival time or the RLF declaration time even if the fixed timer expires. If the condition 3 is satisfied, the terminal immediately triggers transmission of an uplink beam recovery request signal to arrive within a minimum time.

In addition, if RLF is performed first even if condition 3 is not satisfied, or if RLF is declared before the closest PRACH arrival time is reached even if condition 3 is satisfied, the terminal may cancel all beam recovery operations and perform operations according to RLF.

Fig. 2P illustrates a method associated with RLF operation by which a terminal attempts beam recovery request transmission when a specific condition 2 is satisfied, according to an embodiment of the present disclosure.

Referring to fig. 2P, the terminal may simultaneously trigger a beam recovery request when the T310 timer of the RLF is triggered. In this case, the terminal may transmit a beam recovery request trigger message from the RRC layer to the MAC/PHY layer or from the MAC layer to the PHY layer.

In contrast, if a beam problem is detected through

condition

1 or 2, the terminal may transmit it to an upper layer to trigger the T310 timer. To this end, the terminal may transmit a T310 trigger message from the PHY layer to the MAC/RRC layer or from the MAC layer to the RRC layer.

The control channel for declaring the beam failure and the Reference Signal (RS) for measurement of each channel may be an RS and a channel scheduled in advance by the base station.

Candidates for the corresponding beam failure detection RS may include: UE-specific resource scheduling CSI-RSs configured with dedicated signals, including CSI-RSs with characteristics/resources allocated only for terminals; scheduling the CSI-RS using the cell-specific resources configured with the dedicated signal, including the CSI-RS having the characteristics/resources allocated to the unspecified plurality of terminals; and NR-Sync signals (PSS, SSS, PBCH) including synchronization signals and broadcast channel signals having characteristics/resources allocated for unspecified plurality of terminals.

The beam for performing beam recovery, such as a new candidate beam or a beam performed by RACH, may be an RS scheduled in advance by the base station or an RS that can be measured by the terminal itself.

Candidates for the corresponding beam recovery identification RS may include: scheduling the CSI-RS with the UE specific resource configured with the dedicated signal, including the CSI-RS having the characteristic/resource allocated only for the terminal; scheduling the CSI-RS using the cell-specific resources configured with the dedicated signal, including the CSI-RS having the characteristics/resources allocated to the unspecified plurality of terminals; and NR-Sync signals (PSS, SSS, PBCH), including synchronization signals and broadcast channel signals having characteristics/resources allocated for unspecified plurality of terminals.

The Reference Signal (RS) for performing cell level problem detection may be an RS previously scheduled by the base station or an RS measured by the terminal itself.

The RLF declaration method due to the beam recovery failure will now be described.

According to an embodiment of the present disclosure, a terminal may declare RLF when a performed beam recovery operation continuously fails. Specifically, the terminal may declare RLF in the following cases: beam recovery fails N _ RLF1 times (NACK count or failure indication count) consecutively, fails in Timer _ RLF1, fails N _ RLF2 times in Timer _ RLF2 (whether discontinuous or not), receives an RLF declaration request DL signal from the network (or from a node B) in response to a recovery attempt, or fails to attempt to exceed Timer _ RLF3 after a beam failure declaration (condition 1 or 2) (when condition 3 is not satisfied).

Referring to fig. 1Y, the transceivers 1Y-10 of the terminal may transmit and receive signals. The transceiver 1y-10 may transmit and receive signals under the control of the controller 1y-30. The controller 1y-30 of the terminal may control the overall operation of the terminal. The controllers 1y-30 may control the terminal to perform the operations described with reference to fig. 2A through 2P.

For example, the controllers 1y-30 may control: performing beam measurement on at least one transmission beam of the base station and at least one beam of the terminal, transmitting beam measurement information to the base station based on the beam measurement and receiving downlink information through a new base station transmission beam. The new base station transmission beam may be changed based on a relationship between the new base station transmission beam and the current reception beam of the terminal included in the beam measurement information.

If the new base station transmission beam corresponds to the current reception beam of the terminal, the base station transmission beam may be changed without receiving a beam change indication message from the base station. If the new base station transmission beam does not correspond to the current reception beam of the terminal, the controller 1y-30 may control reception of the beam change indication message from the base station.

In addition, the terminal reception beam and the base station transmission beam may be changed after the beam change indication message is transmitted and then a predetermined time elapses. The beam measurement information may include an indicator, and the indicator may indicate whether the terminal can receive the base station transmission beam in a current reception beam of the terminal.

The transceivers 1z-10 of the base stations 1z-00 can transmit and receive signals. The transceivers 1z-10 can transmit and receive signals under the control of the controllers 1z-30. The controllers 1z-30 of the base stations may control the overall operation of the base stations. The controller 1z-30 may control the base station to perform the operations described with reference to fig. 2A to 2P.

For example, the controllers 1z-30 may control: receiving beam measurement information from the terminal, determining a base station transmission beam change for the terminal based on the beam measurement information, and changing a base station transmission beam by a relationship between a new base station transmission beam included in the beam measurement information and a current reception beam of the terminal.

In addition, when the new base station transmission beam corresponds to the current reception beam of the terminal, the base station transmission beam may be changed without transmitting the beam change instruction message. In addition, when the new base station transmission beam does not correspond to the current reception beam of the terminal, the controller 1z-30 may control transmission of the beam change instruction message to the terminal. And, in addition, the base station transmission beam may be changed after the beam change indication message is transmitted and then a predetermined time elapses.

In addition, the beam measurement information may include an indicator, and the indicator may indicate whether the terminal can receive the base station transmission beam in a current reception beam of the terminal

While the disclosure has been shown and described with reference to certain embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure as defined by the appended claims and their equivalents.

Claims

1. A method performed by a base station in a wireless communication system, the method comprising:

transmitting a reporting configuration to a terminal, the reporting configuration including information associated with group-based beam reporting and a number of groups for the group-based beam reporting;

transmitting at least one reference signal for measuring a beam to a terminal; and

receiving, from the terminal, a measurement report comprising N sets of two reference signal received powers, RSRPs, corresponding to two beams from the measurement beams associated with one beam set, N indicating a number of sets of said group-based beam reports,

wherein the two beams associated with the one beam group correspond to reference signals simultaneously received by the terminal.

2. The method of claim 1, wherein one of the RSRPs is 7 bits in length.

3. The method of claim 1, wherein the reporting configuration is sent via Radio Resource Control (RRC) signaling, an

Wherein the at least one reference signal comprises at least one channel state information reference signal, CSI-RS.

4. The method of claim 1, wherein the measurement report includes two identifiers associated with the two beams.

5. A method performed by a terminal in a wireless communication system, the method comprising:

receiving a reporting configuration from a base station, the reporting configuration comprising information associated with group-based beam reporting and a number of groups for group-based beam reporting;

receiving at least one reference signal for measuring a beam from a base station;

determining two beams associated with a beam group corresponding to simultaneously received reference signals; and

reporting, based on a reporting configuration, a measurement report to a base station, the measurement report comprising N sets of two reference signal received powers, RSRPs, corresponding to said two beams from measurement beams associated with said one beam set, N indicating a number of sets of said group-based beam reports.

6. The method of claim 5, wherein one of the RSRPs is 7 bits in length.

7. The method of claim 5, wherein the reporting configuration is received via Radio Resource Control (RRC) signaling, an

8. The method of claim 5, wherein the measurement report includes two identifiers associated with the two beams.

9. A base station in a wireless communication system, the base station comprising:

a transceiver, and

a controller configured to:

transmitting, via the transceiver, a reporting configuration to a terminal, the reporting configuration comprising information associated with group-based beam reporting and a number of groups for group-based beam reporting,

transmitting, via the transceiver, at least one reference signal for measuring a beam to a terminal; and

receiving, via the transceiver, a measurement report from a terminal based on a reporting configuration, the measurement report comprising N sets of two reference signal received powers, RSRP, corresponding to two beams from a measurement beam associated with one beam set, N indicating a number of sets of the group-based beam reports,

10. The base station of claim 9, wherein one of the RSRPs is 7 bits in length.

11. The base station of claim 9, wherein the reporting configuration is transmitted via radio resource control, RRC, signaling, and

12. The base station of claim 9, wherein the measurement report includes two identifiers associated with the two beams.

13. A terminal in a wireless communication system, the terminal comprising:

a transceiver, and

a controller configured to:

receiving, via the transceiver, a reporting configuration from a base station, the reporting configuration comprising information associated with group-based beam reporting and a number of groups for group-based beam reporting;

receiving, via the transceiver, at least one reference signal for a measurement beam from a base station;

reporting, via the transceiver, a measurement report to a base station based on a reporting configuration, the measurement report comprising N sets of two reference signal received powers, RSRP, corresponding to the two beams from measurement beams associated with the one beam set, N indicating a number of sets of the group-based beam reports.

14. The terminal of claim 13, wherein one of the RSRPs is 7 bits in length.

15. The terminal of claim 13, wherein the reporting configuration is received via Radio Resource Control (RRC) signaling,

wherein the at least one reference signal comprises at least one channel state information reference signal, CSI-RS, and

wherein the measurement report includes two identifiers associated with the two beams.