KR20210034477A - Operating method of user equipment and base station in communication system - Google Patents

Abstract

Disclosed is an operation method of a terminal and a base station in a communication system. According to an embodiment of the present invention, the operation method of the terminal includes the steps of: determining whether there is additional data to be transmitted and received with the base station in a radio resource control (RRC) connected state; transmitting user equipment (UE) assistance information to the base station when there is no data to transmitted and received; and transitioning from an RRC connected state to an RRC idle state. Accordingly, it is possible to reduce terminal battery consumption by time saved.

Description

Operation method of terminal and base station in communication system {OPERATING METHOD OF USER EQUIPMENT AND BASE STATION IN COMMUNICATION SYSTEM}

The present invention relates to a method of operating a terminal and a base station in a communication system, and more particularly, to a method of operating a terminal and a method of operating a base station capable of reducing battery consumption of the terminal.

Mobile communication terminals are being used in various fields with continuous development. Related issues are also being raised to supplement and improve. In particular, problems have been raised and improved measures have been proposed regarding the battery efficiency of terminals, and research has been conducted to analyze the problems and increase the efficiency from various viewpoints.

Recently, various attempts have been made to reduce power consumption due to a state transition (between connected/idle) of a terminal. In general, the terminal is provided with a service using a link with a base station and a core network previously connected in the RRC_Connected state. From the viewpoint of the terminal, when there is no further service use, the terminal transitions to an idle state. In this process, a lot of power consumption may occur, resulting in a problem of deteriorating battery efficiency.

In order to solve this problem, various methods such as a method of disconnecting the connection between the terminal and the base station using a separate message, a method of omitting an acknowledgment response to a corresponding message from the terminal side, and transmission of auxiliary information have been proposed. It has resulted in other problems such as loss of messages and loss of efficiency due to transmission of auxiliary information.

An object of the present invention for solving the above problems is to provide a method of operating a terminal that communicates with a base station in a communication system.

Another object of the present invention is to provide a method of operating a base station that communicates with one or more terminals in a communication system.

Another object of the present invention is to provide a terminal that communicates with a base station in a communication system.

In accordance with an embodiment of the present invention for achieving the above object, a method of operating a terminal communicating with a base station in a communication system is to determine whether there is additional data to be transmitted or received with the base station in a radio resource control (RRC) connected state. step; Transmitting user equipment (UE) assistance information to the base station when there is no data to be transmitted/received; And transitioning from the RRC connected state to the RRC idle state.

Transitioning from the RRC connected state to the RRC idle state may be performed immediately after transmitting the UE assistance information to the base station without waiting for a response from the base station to the UE assistance information.

Transitioning from the RRC connected state to the RRC idle state may also be performed immediately after receiving a response from the base station to the UE assistance information.

The UE assistance information may be transmitted through a service request message.

The UE assistance information may also be included as a release assistance indication (RAI) information element (IE) in the service request message.

When the service request message is triggered by the terminal and the state of the terminal is in an RRC connected state, the service request message may indicate an RRC release request.

In order to achieve another object of the present invention, a method of operating a base station according to an embodiment of the present invention includes: receiving UE (User Equipment) assistance information from a terminal; Transmitting a response to the UE assistance information or a radio resource control (RRC) release message to the terminal; And releasing the RRC connection with the terminal.

The UE assistance information may be transmitted through a service request message.

The UE assistance information may also be included as a release assistance indication (RAI) information element (IE) in the service request message.

When the service request message is triggered by the terminal and the state of the terminal is in an RRC connected state, the service request message may indicate an RRC release request.

A terminal according to an embodiment of the present invention for achieving another object of the present invention includes a processor; And it may include a memory (memory) storing one or more instructions executed by the processor, the one or more instructions, whether there is additional data to be transmitted and received with the base station in a radio resource control (RRC) connected state. Command to make judgments; A command to transmit user equipment (UE) assistance information to the base station when there is no data to be transmitted/received; And a command to transition from the RRC connected state to the RRC idle state.

In this case, the command for transitioning from the RRC connected state to the RRC idle state may be performed immediately after transmitting the UE assistance information to the base station without waiting for a response from the base station to the UE assistance information.

In addition, the command for transitioning from the RRC connected state to the RRC idle state may be performed immediately after receiving a response from the base station to the UE assistance information.

In order to achieve another object of the present invention, a method of operating a terminal according to an embodiment of the present invention includes determining whether there is additional data to be transmitted or received with a base station in a radio resource control (RRC) connected state; Initiating an operation of a data inactivity timer when there is no additional data to be transmitted/received; And transitioning to an RRC idle state when the data inactivity timer expires.

The data inactivity timer may be set for each single application or application group executed in the terminal.

The data inactivity timer may also be set for each quality of service (QoS) flow, protocol data unit (PDU) session, or radio bearer.

Meanwhile, the data inactivity timer may be set by a user.

According to the method using the UE assistance information among the embodiments of the present invention, since the terminal can make an earlier state transition to the dormant state compared to the conventional method, the terminal battery consumption can be reduced by the saved time.

In addition, by setting the period of the data activation timer differently according to the user application, it is possible to optimize the time for the terminal to transition to the dormant state according to the traffic pattern and the user usage pattern, thereby reducing the battery consumption of the terminal and the frequency of the state transition of the terminal. .

In addition, by delivering UE assistance information using a service request message, it is expected that the battery consumption of the terminal can be reduced and the overall network load can be reduced through a simple and low complexity method using an existing message without adding a new message. have.

1 is a conceptual diagram illustrating an example of a communication system.
2 is a block diagram showing an embodiment of a communication node constituting a communication system.
3A is a conceptual diagram of a method for transmitting an RRC connection release message in a base station.
3B illustrates the concept of a data inactivity timer according to embodiments of the present invention.
3C illustrates a concept of a method of reducing battery consumption of a terminal using UE assistance information according to embodiments of the present invention.
4 shows elements of RAI (Release assistance indication) information.
5A is a conceptual diagram of a communication method using conventional terminal assistance information.
5B and 5C are conceptual diagrams of a communication method using UE assistance information according to embodiments of the present invention.
5D is a diagram illustrating a result of comparing transition times to an idle state in embodiments according to the present invention compared to the case of using general UE assistance information.
6 shows a transition time difference to an idle state between a case of using UE assistance information and a mechanism using a data inactivity timer according to embodiments of the present invention.
7 shows a state transition of a terminal over time due to an irregular data pattern.
8A shows a method of setting a data inactivity timer value for each application according to an embodiment of the present invention.
8B shows a method of setting a data inactivity timer value for each radio bearer according to an embodiment of the present invention.
8C shows a method of setting a data inactivity timer value for each QoS flow according to an embodiment of the present invention.
8D shows a method of setting a data inactivity timer value for each PDU session according to an embodiment of the present invention.
8E shows an example of setting a data inactivity timer value by a user according to an embodiment of the present invention.
9 is a diagram illustrating a method of delivering UE assistance information using a service request message according to an embodiment of the present invention in a table.
10 shows a procedure for a terminal to transmit a service request message to a network and an amount of power consumption according to a terminal state according to an embodiment of the present invention.
11 is a flowchart of a method of operating a terminal according to an embodiment of the present invention.
12 is a flowchart of a method of operating a base station according to an embodiment of the present invention.

In the present invention, various modifications may be made and various embodiments may be provided, and specific embodiments will be illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to a specific embodiment, it should be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms such as first and second may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another component. For example, without departing from the scope of the present invention, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. The term and/or includes a combination of a plurality of related listed items or any of a plurality of related listed items.

When a component is referred to as being "connected" or "connected" to another component, it is understood that it may be directly connected or connected to the other component, but other components may exist in the middle. It should be. On the other hand, when a component is referred to as being "directly connected" or "directly connected" to another component, it should be understood that there is no other component in the middle.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, but one or more other features. It is to be understood that the presence or addition of elements or numbers, steps, actions, components, parts, or combinations thereof does not preclude in advance.

Unless otherwise defined, all terms used herein including technical or scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms as defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in this application. Does not.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. In describing the present invention, in order to facilitate an overall understanding, the same reference numerals are used for the same elements in the drawings, and duplicate descriptions for the same elements are omitted.

A communication system to which embodiments according to the present invention are applied will be described. The communication system to which the embodiments according to the present invention are applied is not limited to the contents described below, and the embodiments according to the present invention can be applied to various communication systems. Here, the communication system may have the same meaning as a communication network.

1 is a conceptual diagram illustrating an example of a communication system.

Referring to FIG. 1, the communication system 100 includes a plurality of communication nodes 110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, 130-4, 130-5, 130-6). The plurality of communication nodes are 4G communication (e.g., long term evolution (LTE), LTE-A (advanced)), 5G communication (e.g., new radio) specified in the 3rd generation partnership project (3GPP) standard. ), etc. 4G communication may be performed in a frequency band of 6 GHz or less, and 5G communication may be performed in a frequency band of 6 GHz or more as well as a frequency band of 6 GHz or less.

For example, for 4G communication and 5G communication, a plurality of communication nodes may include a code division multiple access (CDMA)-based communication protocol, a wideband CDMA (WCDMA)-based communication protocol, a time division multiple access (TDMA)-based communication protocol, Frequency division multiple access (FDMA)-based communication protocol, OFDM (orthogonal frequency division multiplexing)-based communication protocol, Filtered OFDM-based communication protocol, CP (cyclic prefix)-OFDM-based communication protocol, DFT-s-OFDM (discrete) Fourier transform-spread-OFDM)-based communication protocol, OFDMA (orthogonal frequency division multiple access)-based communication protocol, SC (single carrier)-FDMA-based communication protocol, NOMA (Non-orthogonal Multiple Access), GFDM (generalized frequency) Division multiplexing) based communication protocol, FBMC (filter bank multi-carrier) based communication protocol, UFMC (universal filtered multi-carrier) based communication protocol, SDMA (Space Division Multiple Access) based communication protocol, etc. can be supported. .

In addition, the communication system 100 may further include a core network. When the communication system 100 supports 4G communication, the core network may include a serving-gateway (S-GW), a packet data network (PDN)-gateway (P-GW), a mobility management entity (MME), and the like. have. When the communication system 100 supports 5G communication, the core network may include a user plane function (UPF), a session management function (SMF), an access and mobility management function (AMF), and the like.

Meanwhile, a plurality of communication nodes 110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, 130- constituting the communication system 100 4, 130-5, 130-6) Each may have the following structure.

2 is a block diagram showing an embodiment of a communication node constituting a communication system.

Referring to FIG. 2, the communication node 200 may include at least one processor 210, a memory 220, and a transmission/reception device 230 connected to a network to perform communication. In addition, the communication node 200 may further include an input interface device 240, an output interface device 250, and a storage device 260. Each of the components included in the communication node 200 may be connected by a bus 270 to communicate with each other.

However, each of the components included in the communication node 200 may be connected through an individual interface or an individual bus based on the processor 210 instead of the common bus 270. For example, the processor 210 may be connected to at least one of the memory 220, the transmitting/receiving device 230, the input interface device 240, the output interface device 250, and the storage device 260 through a dedicated interface. .

The processor 210 may execute a program command stored in at least one of the memory 220 and the storage device 260. The processor 210 may mean a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor in which methods according to embodiments of the present invention are performed. Each of the memory 220 and the storage device 260 may be configured with at least one of a volatile storage medium and a nonvolatile storage medium. For example, the memory 220 may be composed of at least one of read only memory (ROM) and random access memory (RAM).

When the communication node 200 is a terminal, the terminal according to an embodiment of the present invention includes a processor; And it may include a memory (memory) storing one or more instructions executed by the processor, the one or more instructions, whether there is additional data to be transmitted and received with the base station in a radio resource control (RRC) connected state. Command to make judgments; A command to transmit user equipment (UE) assistance information to the base station when there is no data to be transmitted/received; And a command to transition from the RRC connected state to the RRC idle state.

In this case, the command for transitioning from the RRC connected state to the RRC idle state may be performed immediately after transmitting the UE assistance information to the base station without waiting for a response from the base station to the UE assistance information.

In addition, the command for transitioning from the RRC connected state to the RRC idle state may be performed immediately after receiving a response from the base station to the UE assistance information.

Referring back to FIG. 1, the communication system 100 includes a plurality of base stations 110-1, 110-2, 110-3, 120-1, 120-2, and a plurality of terminals 130- 1, 130-2, 130-3, 130-4, 130-5, 130-6). Base stations (110-1, 110-2, 110-3, 120-1, 120-2) and terminals (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) The containing communication system 100 may be referred to as an “access network”. Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 may form a macro cell. Each of the fourth base station 120-1 and the fifth base station 120-2 may form a small cell. The fourth base station 120-1, the third terminal 130-3, and the fourth terminal 130-4 may belong to the cell coverage of the first base station 110-1. The second terminal 130-2, the fourth terminal 130-4, and the fifth terminal 130-5 may belong to the cell coverage of the second base station 110-2. The fifth base station 120-2, the fourth terminal 130-4, the fifth terminal 130-5, and the sixth terminal 130-6 may belong within the cell coverage of the third base station 110-3. have. The first terminal 130-1 may belong to the cell coverage of the fourth base station 120-1. The sixth terminal 130-6 may belong to the cell coverage of the fifth base station 120-2.

Here, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 is a NodeB, an evolved NodeB, gNB, and a base transceiver station (BTS). ), a radio base station, a radio transceiver, an access point, an access node, and the like. Each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 is a user equipment (UE), a terminal, an access terminal, and a mobile device. It may be referred to as a mobile terminal, a station, a subscriber station, a mobile station, a portable subscriber station, a node, a device, and the like.

Meanwhile, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may operate in different frequency bands or may operate in the same frequency band. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be connected to each other through an ideal backhaul link or a non-ideal backhaul link, , Information can be exchanged with each other through an ideal backhaul link or a non-ideal backhaul link. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be connected to the core network through an ideal backhaul link or a non-ideal backhaul link. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 transmits a signal received from the core network to the corresponding terminal 130-1, 130-2, 130-3, 130 -4, 130-5, 130-6), and the signal received from the corresponding terminal (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) is transmitted to the core network. Can be transferred to.

In addition, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 transmits MIMO (eg, single user (SU)-MIMO, multi-user (MU)- MIMO, massive MIMO, etc.), coordinated multipoint (CoMP) transmission, carrier aggregation (CA) transmission, transmission in an unlicensed band, direct communication between terminals (device to device communication, D2D) (or, ProSe ( proximity services)). Here, each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 is the base station 110-1, 110-2, 110-3, 120-1 , 120-2) and operations supported by the base stations 110-1, 110-2, 110-3, 120-1, and 120-2. For example, the second base station 110-2 may transmit a signal to the fourth terminal 130-4 based on the SU-MIMO scheme, and the fourth terminal 130-4 can transmit a signal to the fourth terminal 130-4 by the SU-MIMO scheme. A signal may be received from the second base station 110-2. Alternatively, the second base station 110-2 may transmit a signal to the fourth terminal 130-4 and the fifth terminal 130-5 based on the MU-MIMO method, and the fourth terminal 130-4 And each of the fifth terminal 130-5 may receive a signal from the second base station 110-2 by the MU-MIMO method.

Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 may transmit a signal to the fourth terminal 130-4 based on the CoMP scheme, and The terminal 130-4 may receive signals from the first base station 110-1, the second base station 110-2, and the third base station 110-3 by the CoMP method. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 has terminals 130-1, 130-2, 130-3, and 130-4 belonging to their cell coverage. , 130-5, 130-6) and CA schemes to transmit and receive signals. Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 can control D2D between the fourth terminal 130-4 and the fifth terminal 130-5. And each of the fourth terminal 130-4 and the fifth terminal 130-5 may perform D2D under the control of each of the second base station 110-2 and the third base station 110-3. .

Methods of operating a communication node in a communication system described below will be described. Even when a method performed in the first communication node (for example, transmission or reception of a signal) among communication nodes is described, the second communication node corresponding thereto is a method corresponding to the method performed in the first communication node (e.g. For example, signal reception or transmission) may be performed. That is, when the operation of the terminal is described, the corresponding base station may perform the operation corresponding to the operation of the terminal. Conversely, when the operation of the base station is described, a terminal corresponding thereto may perform an operation corresponding to the operation of the base station.

Research is being conducted to increase the battery efficiency of a communication terminal operating in the communication system as described above.

One of the existing methods is a method of releasing a radio section connection between the terminal and the base station by transmitting an RRCRelease message from the base station when the terminal no longer uses a service.

3A shows the concept of a method for transmitting an RRC connection release message in a base station. In the case of this method, when there is no further uplink/downlink data transmission/reception, the base station transmits an RRC connection release message to the terminal. In this case, a release delay occurs due to the message transmission and confirmation procedure, and here The power consumption was large due to the time it took.

As a proposed method to compensate for this, a method of rapidly proceeding the procedure by omitting ack/nack from the terminal side for the RRCRelease message has been proposed. The method of omitting ack/nack of the terminal side has the advantage of reducing power loss as much as the omitted procedure than the conventional method, but when the RRCRelease message is lost, there is a problem in that a state mismatch between the terminal and the base station occurs.

3B illustrates the concept of a data inactivity timer according to embodiments of the present invention. The data inactivity timer presented through FIG. 3B is proposed as a method for preventing the problem of loss of the RRCRelease message. This method is a room in which the terminal defines the DataInactivityTimer and operates the timer after the service is terminated so that the state transitions from RRC_Conntected to RRC_Idle when the timer expires. In this method, even if the RRCRelease message is lost, when the timer on the terminal side expires, the terminal transitions to the idle state, so that the message loss problem can be solved. However, when the DataInactivityTimer is operated, power loss according to the timer time is inevitable. In addition, if the timer is set short, there may be a problem that the frequency of state transition increases. In this regard, if the period of the timer is set for a long time, another problem that power consumption increases by that amount may arise.

3C illustrates a concept of a method of reducing battery consumption of a terminal using UE assistance information according to embodiments of the present invention. The scheme shown in FIG. 3C is proposed to complement the schemes proposed for solving the above-described various problems and problems, and when the terminal side no longer uses the service, a UE assistance information message is transmitted to the base station. By doing this, the waiting time is minimized and released.

As a more specific method for transmitting UE assistance information, various methods have been proposed through the 3GPP standardization meeting, and as a result, RAI (Release assistance indication) is defined and information for release from the UE is transmitted to the base station. The procedure to do is proposed.

4 shows elements of RAI (Release assistance indication) information.

The purpose of RAI (Release Assistance Indication) IE (Information element) is whether additional uplink and additional downlink data transmission is not expected, or only one downlink data transmission (e.g., confirmation or response to the corresponding uplink data). ) Is expected and no further uplink data transmission is expected.

As shown in FIG. 4, the RAI IE is a type 1 IE composed of 8 bits, and a downlink data expected (DDX) type may be expressed through bits 1 and 2.

However, the UE assistance indication mechanism is highly efficient when it is data of a regular and intermittent pattern, but for data of an irregular and frequently occurring pattern, state transitions frequently occur, resulting in lowering the UE assistance information efficiency. Occurs.

Accordingly, the present invention proposes a method for reducing power consumption generated in a state transition process of a terminal.

Specifically, in order to solve the above-described problem, in the present invention, first, a UE assistance information message transmission mechanism is proposed that effectively switches the terminal to the dormant state faster than the conventional method.

Second, by defining multiple DataInactivityTimers and setting the DataInactivityTimer time differently according to traffic characteristics, it is intended to improve the problem of inefficient terminal power consumption by improving frequent state transitions that occur due to irregular and frequent data patterns when the data inactivity timer is applied.

Finally, as a RAI (Release assistance indication) scheme, the UE intends to transmit more effective release information to the base station by using an existing procedure.

Applying the embodiments according to the present invention can have an effect of improving not only battery efficiency but also a problem occurring in an exceptional situation compared to the existing method.

UE assistance information mechanism

5A is a conceptual diagram of a communication method using conventional terminal assistance information.

Referring to FIG. 5A showing a typical UE assistance information mechanism, the UE transmits UE assistance information to the base station before the DataInactivityTimer time, and the UE transitions to the dormant state through the RRC connection release procedure. The terminal operates the DataInactivityTimer in case the RRC connection release message transmitted by the base station is lost.

In this scheme, when the terminal no longer uses a service, the UE transmits a UE assistance information message to the base station to trigger RRC release, thereby enabling a faster transition to the dormant state. However, power consumption still occurs due to the time required for the RRC release procedure.

5B and 5C are conceptual diagrams of a communication method using UE assistance information according to embodiments of the present invention.

In the embodiments shown in FIGS. 5B and 5C, two methods of reducing power consumption due to the RRC release procedure are proposed compared to the conventional method. 5B shows an embodiment in which the terminal transitions to the dormant state after receiving an ACK for UE assistance information, and FIG. 5C shows an example in which the UE immediately transitions to the dormant state after transmitting the UE assistance information.

Referring to FIG. 5B, when there is no more data to be transmitted/received, the UE transmits a UE assistance information message to the base station. Upon receiving the corresponding message from the terminal, the base station transmits an Ack message for UE assistance information to the terminal without performing an RRC release procedure. Upon receiving the Ack message from the base station, the terminal transitions to the dormant state.

5C, the UE transmits a UE assistance information message to the base station, and immediately transitions to the dormant state. The base station receiving the message from the terminal transmits an RRC_Connection release message to the terminal as an RRC release procedure. At this time, since the terminal has already transitioned to the dormant state, the ack message for the corresponding message cannot be transmitted to the base station. Accordingly, the base station transmits the RRC_connection release message to the terminal and then performs transmission by presetting a predetermined time or the number of initial transmission and retransmission, and determines that the terminal is in an idle state when there is no ack from the terminal.

Both of the methods proposed through FIGS. 5B and 5C can reduce terminal battery consumption by transitioning to the dormant state earlier than the conventional method.

5D is a diagram illustrating a result of comparing transition times to an idle state of embodiments according to the present invention compared to the case of using general UE assistance information.

Referring to FIG. 5D, it can be seen that a state transition from the terminal to the dormant state is made earlier in the case of the first method and the second method proposed in this patent, rather than the conventional general UE assistance information mechanism.

As described above, in the method using the UE assistance information, when the terminal no longer uses a service, the UE transmits a corresponding message to the base station to trigger RRC release, so that it is possible to transition to the dormant state earlier than the time when the DataInactivityTimer expires.

6 shows a transition time difference 60 to an idle state between a case of using UE assistance information and a mechanism using a data inactivity timer according to embodiments of the present invention.

However, when the data traffic pattern of the terminal is irregular and frequently occurs and is unpredictable, if the method using the UE auxiliary information is used, unnecessary state transitions of the terminal (idle <-> connected) are frequently generated, which rather reduces the battery efficiency of the terminal. It can result in dropping.

7 shows a state transition of a terminal over time due to an irregular data pattern.

Referring to FIG. 7, it can be seen that RRC connection and RRC release are repeated for a not long time. In this way, if the UE auxiliary information is used when the traffic pattern for the service use of the UE is not constant and occurs irregularly, performance degradation may occur due to the UE state transition procedure, which is frequently generated due to early idle state transition. .

Multiple DataInactivityTimers

Rather than transitioning to the dormant state using UE assistance information for irregular traffic patterns, using a mechanism using a data inactivity timer can reduce the frequency of the state transition of the terminal when data is received within the time period, and accordingly. The efficiency can be higher.

However, since the user's traffic pattern is different for each service used, even if the DataInactivityTimer method is applied, the terminal power consumption can be reduced by properly setting a timer duration. For example, if there is an application that sends traffic every 10 seconds and there is an application every 4 seconds, it is desirable to set the value of DataInactivityTimer that can minimize power consumption by considering both the data transmission/reception cycles of the two applications. Do.

However, it is not easy to set an appropriate DataInactivityTimer value because there are a myriad of applications existing in the terminal, and the application usage pattern of the user and the traffic pattern of the application are different. Accordingly, in the present invention, a plurality of DataInactivityTimers are set and the DataInactivityTimer values are mapped differently according to traffic and App usage patterns to minimize power consumption of the terminal.

The first of the embodiments of setting the DataInactivityTimer value in the present invention is a method of setting one DataInactivityTimer value per App.

8A shows a method of setting a data inactivity timer value for each application according to an embodiment of the present invention. Referring to FIG. 8A, the terminal may operate a timer by setting a DataInactivityTimer value for each application based on traffic pattern information of a user App.

The second method is a method of setting a Quality of Service (QoS) flow id, a Protocol Data Unit (PDU) session, and a DataInactivityTimer value per radio bearer.

8B shows a method of setting a data inactivity timer value for each radio bearer according to an embodiment of the present invention.

8C shows a method of setting a data inactivity timer value for each QoS flow according to an embodiment of the present invention. 8D shows a method of setting a data inactivity timer value for each PDU session according to an embodiment of the present invention.

The third method is to set the user-defined DataInactivityTimer value. 8E shows an example of setting a data inactivity timer value by a user according to an embodiment of the present invention. Since the user knows the usage pattern of the application in the terminal, multiple DataInactivityTimer values can be set and the user can directly map the App to the DataInactivityTimer value. In the example shown in FIG. 8E, the user has associated T1 with app1, T3 with app2, and T3 with appn.

8A to 8E are summarized in terms of the operation of the terminal, in the operating method of the terminal according to an embodiment of the present invention, data to be transmitted and received with the base station in a radio resource control (RRC) connected state is Determining whether there is additional; Initiating an operation of a data inactivity timer when there is no additional data to be transmitted/received; When the data inactivity timer expires, transitioning to an RRC idle state may be included.

In this case, the data inactivity timer may be set for each single application or application group executed in the terminal. The data inactivity timer may also be set for each quality of service (QoS) flow, protocol data unit (PDU) session, or radio bearer.

Meanwhile, the data inactivity timer may be set by the user.

UE assistance information method

The present invention also proposes a method of transmitting UE assistance information. In this specification, a method of appropriately transmitting UE assistance information using a message provided by an existing standard is proposed.

More specifically, the present invention proposes a method of transmitting UE assistance information through a service request message. The service request is a message transmitted by the terminal when the terminal is registered in the network and receives a signal indicating that there is traffic to be transmitted or traffic to be transmitted from the network in the RRC_idle state.

9 is a diagram illustrating a method of delivering UE assistance information using a service request message according to an embodiment of the present invention in a table.

Referring to FIG. 9, if there is uplink data to be transmitted to the network, the terminal may trigger a service request Case 1 situation. Conversely, if there is downlink data to be transmitted from the network to the terminal, it can be triggered by the network as a service request Case 2 situation. In the present invention, a new service request case is defined when the terminal is in a connected state (eg, Service Request Case n). That is, when the terminal transmits the service request message in the RRC connected state, the base station determines that the RRC connection should be released, and performs a connection release procedure. That is, a service request message is used as a means of transmitting UE assistance information. Here, the UE assistance information may be included in a service request message in the form of a release assistance indication (RAI) information element (IE).

According to this embodiment of the present invention, the advantage of using a Service Request, which is a message that already exists in the standard, and only a simple case is added to the existing message, so that the implementation is simple and the effect of low complexity can be obtained.

10 shows a procedure for a terminal to transmit a service request message to a network and an amount of power consumption according to a terminal state according to an embodiment of the present invention.

Referring to FIG. 10, when a terminal transmits a service request message corresponding to an RRC release request to a base station (eNB or gNB), the base station transmits a UL NAS ((Non- Access Stratum) transport or an N2 message to a mobility management entity (MME). ) Or an access and mobility management function (AMF) to perform an RRC release procedure, that is, a service request message is used to deliver a release assistance indication (RAI).

In this case, as described above in the embodiments of the present invention, the terminal may transmit a service request message to the base station and immediately transition to the RRC idle state. In addition, the terminal may transition to the dormant state immediately upon receiving the Ack message for the service request message from the base station.

Accordingly, as described with reference to FIGS. 5B, 5C, and 6, it is possible to reduce the power consumption of the terminal.

11 is a flowchart of a method of operating a terminal according to an embodiment of the present invention.

A terminal according to an embodiment of the present invention can operate while communicating with a base station in a communication system.

Referring to FIG. 11, a method of operating a terminal according to an embodiment of the present invention is disclosed on the assumption that the terminal is in a radio resource control (RRC) connected state (S1101). The terminal determines whether there is additional data to be transmitted and received with the base station in the RRC connected state (S1102). When there is no data to be transmitted/received, the terminal may transmit user equipment (UE) assistance information to the base station (S1103).

Thereafter, the terminal may receive a response from the base station to the UE assistance information (S1104), and then transition from the RRC connected state to the RRC idle state (S1105).

Meanwhile, depending on the operation method, the terminal may immediately transition to the RRC idle state immediately after transmitting the UE assistance information to the base station without waiting for a response from the base station to the UE assistance information (S1105). That is, the step (S1104) of waiting for a response from the base station to the UE assistance information from the standpoint of the terminal may be an optional step that may be omitted.

12 is a flowchart of a method of operating a base station according to an embodiment of the present invention.

Referring to FIG. 12, a base station according to an embodiment of the present invention may operate while communicating with one or more terminals in a communication system.

The base station receives user equipment (UE) assistance information from the terminal (S1210) and is notified that there is no more data to be transmitted or received by the terminal. In this case, the UE assistance information may be transmitted from the terminal to the base station through a service request message. In addition, the UE assistance information may be included as a release assistance indication (RAI) information element (IE) in the service request message.

The base station performs an RRC connection release procedure whose detailed operation is slightly different depending on the operation method.

First, in the case of following the first scheme, the base station may perform an RRC connection release procedure with the corresponding terminal after transmitting a response (Ack) for the UE assistance information received from the terminal to the terminal (S1220) (S1250). .

Meanwhile, according to the second method, the base station receives the UE assistance information from the terminal (S1210), and transmits an RRC release message to the terminal without transmitting a separate response (ack) for the UE assistance information to the terminal (S1230). Thereafter, if the response from the terminal is not received within a predetermined time or within a predetermined number of transmissions, it is determined that the terminal has already transitioned to the dormant state (S1231). The base station determined that the terminal is in the dormant state may perform an RRC connection release procedure with the corresponding terminal (S1250).

The methods according to the present invention may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like alone or in combination. The program instructions recorded on the computer-readable medium may be specially designed and configured for the present invention, or may be known and usable to those skilled in computer software.

Examples of computer-readable media include hardware devices specially configured to store and execute program instructions, such as rom, ram, flash memory, and the like. Examples of program instructions include machine language codes such as those produced by a compiler, as well as high-level language codes that can be executed by a computer using an interpreter or the like. The above-described hardware device may be configured to operate as at least one software module to perform the operation of the present invention, and vice versa.

Although described with reference to the above embodiments, those skilled in the art will understand that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention described in the following claims. I will be able to.

Claims (20)

As an operating method of a terminal communicating with a base station in a communication system,
Determining whether there is additional data to be transmitted or received with the base station in a radio resource control (RRC) connected state;
Transmitting user equipment (UE) assistance information to the base station when there is no data to be transmitted/received; And
Including the step of transitioning from the RRC connected state to the RRC idle (idle) state, the operating method of the terminal. The method according to claim 1,
Transitioning from the RRC connected state to the RRC idle state,
Immediately after transmitting the UE assistance information to the base station, it is performed without waiting for a response from the base station to the UE assistance information. The method according to claim 1,
Transitioning from the RRC connected state to the RRC idle state,
Performed immediately after receiving a response from the base station to the UE assistance information, the operating method of the terminal. The method according to claim 1,
The UE assistance information is transmitted through a service request message. The method of claim 4,
The UE assistance information is included as a Release assistance indication (RAI) Information Element (IE) in the service request message. The method of claim 4,
When the service request message is triggered by the terminal and the state of the terminal is in an RRC connected state, the service request message indicates an RRC release request. As a method of operating a base station in a communication system,
Receiving user equipment (UE) assistance information from the terminal;
Transmitting a response to the UE assistance information or a radio resource control (RRC) release message to the terminal; And
Including the step of releasing the RRC connection with the terminal, the operating method of the base station. The method of claim 7,
The UE assistance information is transmitted through a service request message. The method of claim 7,
The UE assistance information is included as a release assistance indication (RAI) information element (IE) in a service request message. The method of claim 9,
When the service request message is triggered by the terminal and the state of the terminal is an RRC connected state, the service request message indicates an RRC release request. As a terminal operating in a communication system,
Processor; And
It includes a memory (memory) storing one or more instructions executed by the processor,
The one or more commands,
A command to determine whether there is additional data to be transmitted or received with the base station in a radio resource control (RRC) connected state;
A command to transmit user equipment (UE) assistance information to the base station when there is no data to be transmitted/received; And
Including a command to transition from the RRC connected state to the RRC idle (idle) state, the terminal. The method of claim 11,
The command to transition from the RRC connected state to the RRC idle state,
Immediately after transmitting the UE assistance information to the base station, it is performed without waiting for a response from the base station to the UE assistance information. The method of claim 11,
The command to transition from the RRC connected state to the RRC idle state,
A terminal performed immediately after receiving a response from the base station to the UE assistance information. The method of claim 11,
The UE assistance information is transmitted through a service request message. The method of claim 14,
The UE assistance information is included as a Release assistance indication (RAI) Information Element (IE) in the service request message. The method of claim 14,
When the service request message is triggered by the terminal and the state of the terminal is in an RRC connected state, the service request message indicates an RRC release request. As an operating method of a terminal communicating with a base station in a communication system,
Determining whether there is additional data to be transmitted or received with the base station in a radio resource control (RRC) connected state;
Initiating an operation of a data inactivity timer when there is no additional data to be transmitted/received; And
And transitioning to an RRC idle state when the data inactivity timer expires. The method of claim 17,
The data inactivity timer,
A method of operating a terminal, which is set for each single application or application group executed in the terminal. The method of claim 17,
The data inactivity timer,
QoS (Quality of Service) flow, PDU (Protocol Data Unit) session, or set for each radio bearer, the operating method of the terminal. The method of claim 17,
The data inactivity timer is set by a user.

Images