WO2012047919A1

WO2012047919A1 - Measurement control method and radio terminal

Info

Publication number: WO2012047919A1
Application number: PCT/US2011/054805
Authority: WO
Inventors: Henry Chang; Noriyoshi Fukuta
Original assignee: Kyocera Corporation
Priority date: 2010-10-04
Filing date: 2011-10-04
Publication date: 2012-04-12

Abstract

A measurement control method in a mobile communication system including a radio terminal which supports MDT defined in a 3GPP standard, includes: a step in which the radio terminal performs a measurement process with respect to the network, according to an MDT configuration message received from the network; and a step in which when a battery remaining amount value indicating a battery remaining amount of the radio terminal becomes less than a battery threshold value during the measurement process, the radio terminal cancels the measurement process.

Description

DESCRIPTION

MEASUREMENT CONTROL METHOD AND RADIO TERMINAL TECHNICAL FIELD

The present invention relates to a measurement control method of controlling a measurement process in MDT defined in the 3GPP, and a radio terminal therefor. BACKGROUND ART

In a mobile communication system, if a building is built in the vicinity of a base station, or if the installation status of a base station in the vicinity of the base station changes, the radio communication environment according to the base station changes. Therefore, conventionally, the operators make use of a measurement vehicle in which measurement equipment is loaded, and perform a drive test by measuring the state of a signal received from the base stations, and then collecting the measurement data.

Such a measurement and collection process can, for example, contribute to the optimization of coverage of the base station, but faces the problem of too many man-hours and high cost. Thus, according to 3GPP (3rd Generation Partnership Project), i.e., a standardi zation proj ect for mobile communication systems, a radio terminal belonging to the user is used to proceed with the specification planning of MDT (Minimization of Drive Test) for automation of the measurement and collection (see 3GPP TR 36.805 V9.0.0 & 3GPP TS 37.320 vlO.1.0).

As a type of the MDT, there exists a record-type MDT (hereinafter, appropriately referred to as "Logged MDT") In the current specifications, according to the Logged MDT, a radio terminal in an idle state measures a reception signal state according to measurement parameters (measurement conditions) specified from a network, records a measurement result as measurement data together with Location information and time information, and reports the recorded measurement data to the network later. SUMMARY OF THE INVENTION

In the Logged MDT, the radio terminal continuously performs a process of measuring the reception signal state to record the measurement data until a measurement duration specified from the network expires, resulting in an increase in the power consumption of the radio terminal as compared with the case in which such a process is not performed. As a consequence, there is a problem that if the battery remaining amount of the radio terminal is exhausted, even in the case of an emergency call, outgoing and incoming operations and the like may not be performed.

Therefore, the present invention provides a measurement control method and a radio terminal by which it is possible to correct an adverse effect caused by an increase in power consumption due to MDT.

In order to solve the problems described above, the present invention has the following features.

According to a feature of a measurement control method of the present invention, there is provided a measurement control method in a mobile communication system including a radio terminal (e.g. UE 200) which supports MDT defined in a 3GPP standard, and a network, (e.g. E-UTRAN 10) which communicates with the radio terminal, the measurement control method comprising: a step in which the radio terminal performs a measurement process with respect to the network, according to an MDT configuration message received from the network; and a step in which when a battery remaining amount value indicating a battery remaining amount of the radio terminal becomes less than a battery threshold value during the measurement process, the radio terminal cancels the measurement process.

According to another feature of a measurement control method of the present invention, the measurement process includes a process for recording a measurement result in addition to a process for measuring a reception signal state .

According to another feature of a measurement control method of the present invention, in the step of performing the measurement process, in an idle state, the radio terminal performs the measurement process according to the MDT configuration message.

According to another feature of a measurement control method of the present invention, the MDT configuration message includes information specifying a measurement duration that is a duration from a measurement parameter included in the MDT configuration message is set to the radio terminal until the measurement process is completed, and the step of cancelling includes a step of stopping a first timer (e.g. 48-hour timer 264) configured to count the measurement duration.

According to another feature of a measurement control method of the present invention, the radio terminal is configured to hold the recorded measurement result until a predetermined time lapses after the measurement process is completed, and the step of cancelling includes a step of activating a second timer (e.g. duration timer 263) configured to count the predetermined time.

According to another feature of a measurement control method of the present invention, the battery remaining amount value is determined according to a voltage value of a battery provided in the radio terminal.

According to another feature of a measurement control method of the present invention, the battery remaining amount value indicates a ratio of a current voltage value with respect to a maximum voltage value of the battery.

According to another feature of a measurement control method of the present invention, the battery threshold value is set to a value larger than zero.

According to another feature of a measurement control method of the present invention, the battery threshold value is set in the radio terminal in advance.

According to another feature of a measurement control method of the present invention, the MDT configuration message includes information specifying the battery threshold value.

According to another feature of a measurement control method of the present invention, the MDT configuration message includes specific information used for determining whether to permit cancellation of the measurement process, and in the step of cancelling, when the battery remaining amount value becomes less than the battery threshold value and it is determined that the cancellation of the measurement process is permitted based on the specific information during the measurement process, the radio terminal cancels the measurement process.

According to another feature of a measurement control method of the present invention, the specific information indicates a network entity having determined to cause the radio terminal to perform the measurement process, and when the determined network entity is a base station, it is determined that the cancellation of the measurement process is permitted.

According to another feature of a measurement control method of the present invention, the radio terminal further comprises a step of continuing the measurement process without cancelling the measurement process, when it is determined that the cancellation of the measurement process is not permitted based on the specific information, during the measurement process and even when the battery remaining amount value becomes less than the battery threshold value.

According to another feature of a measurement control method of the present invention, the specific information indicates a network entity having determined to cause the radio terminal to perform the measurement process, and when the determined network entity is an upper apparatus of a base station, it is determined that the cancellation of the measurement process is not permitted.

According to another feature of a measurement control method of the present invention, the measurement control method further comprises a step of sending a message used for sending measurement data obtained by the measurement process, to the network from the radio terminal, wherein after the measurement process is cancelled in the step of cancelling, the radio terminal sends predetermined information on cancellation of the measurement process, while the predetermined information is included in the message, in the step of sending the message.

According to another feature of a measurement control method of the present invention, the predetermined information indicates that the measurement process is cancelled because the battery remaining amount value becomes less than the battery threshold value.

According to another feature of a measurement control method of the present invention, the measurement control method further comprises a step in which the network controls transmission of the MDT configuration message to the radio terminal based on the predetermined information included in the message from the radio terminal.

According to another feature of a measurement control method of the present invention, the step of controlling includes a step in which when cancellation information is included in the message from the radio terminal, the network regulates the transmission of the MDT configuration message to the radio terminal.

According to another feature of a measurement control method of the present invention, the step of controlling further comprises a step in which when cancellation information is included in the message from the radio terminal, the network shares the cancellation information between network entities included in the network.

According to a feature of a radio terminal of the present invention, there is provided a radio terminal which supports MDT defined in a 3GPP standard, the radio terminal comprising: a measurement processing unit (e.g. logging processing unit 261) configured to perform a measurement process with respect to a network, according to an MDT configuration message received from the network; and a measurement control unit (e.g. logging control unit 262) configured to cancel the measurement process when a battery remaining amount value indicating a battery remaining amount of the radio terminal becomes less than a battery threshold value during the measurement process.

BRIEF DESCRIPTION OF THE DRAWINGS

[Fig. 1] Fig. 1 is a diagram showing an entire configuration of mobile communication systems according to a first embodiment to a third embodiment.

[Fig. 2] Fig. 2 is a block diagram of eNB (base station) according to the first embodiment to the third embodiment.

[Fig. 3] Fig. 3 is a block diagram of UE (radio terminal) according to the first embodiment to the third embodiment .

[Fig. 4] Fig. 4 is an operation flowchart of the UE according to the first embodiment, and illustrates an operation from setting of a measurement parameter to a logging completion.

[Fig. 5] Fig. 5 is an operation flowchart of the UE according to the first embodiment to the third embodiment, and illustrates an operation after logging completion/cancellation .

[Fig. 6] Fig. 6 is an operation flowchart of the UE according to the second embodiment, and illustrates an operation from setting of a measurement parameter to a logging completion.

[Fig. 7] Fig. 7 is an operation flowchart of the UE according to the third embodiment, and illustrates an operation from setting of a measurement parameter to a logging completion.

[Fig. 8] Fig. 8 is an operation sequence diagram of a mobile communication system according to a fourth embodiment, and illustrates an operation after the UE completes/cancels a logging process. DESCRIPTION OF EMBODIMENTS

A first embodiment to a fourth embodiment, and other embodiments of the present invention are explained below with reference to drawings. In the drawings of each of the embodiments shown below, the same or similar symbols have been used in the same or similar portions.

[First embodiment]

(Overview of mobile communication system)

Fig. 1 is a diagram showing an entire configuration of a mobile communication system 1 according to the present embodiment. The mobile communication system 1 according to the present embodiment is configured based on LTE (Long Term Evolution) or LTE-Advanced, whose specifications are stipulated in 3GPP, and supports the above-mentioned Logged MD .

As shown in Fig. 1, the mobile communication system

1 includes eNB (evolved Node-B) 100, UE (User Equipment) 200, MME (Mobility Management Entity) /S-GW (Serving- Gateway) 310, and 0AM (Operation and Maintenance ) 320. In the present embodiment, the eNB 100 corresponds to a base station, and the UE 200 corresponds to a radio terminal.

A plurality of eNBs 100 configure E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network) 10, which is the radio access network of LTE. A plurality of MME/S-GWs 310 configure EPC (Evolved Packet Core) 300 which is an LTE core network. In the present embodiment, the E-UTRAN 10 and the EPC 300 configure a network. Furthermore, the OAM 320 may also be included in the network .

Each eNB 100 is a fixed radio communication device set up by an operator, and is configured to perform radio communication with the UE 200. Each eNB 100 communicates with neighbor eNB 100 on an X2 interface, and communicates with the MME/S-GW 310 on an SI interface. Each eNB 100 forms one or more cells, which are the smallest units of the radio communication area. Each eNB 100 always broadcasts a reference signal that enables the identification of cells.

The UE 200 is a transportable radio communication device belonging to the user. The UE 200 has a battery and is driven by power accumulated in the battery. The UE 200 is configured to connect to the eNB 100 and to enable communication with the communication destination via the eNB 100. The state when the UE 200 is communicating with the communication destination is called the connected state, and the state when the UE 200 is waiting for communication is called the idle state.

The eNB 100, if necessary, sends a Logged Measurement Configuration message used for performing the Logged MDT to a locally connected (in connected state) UE 200. In the present embodiment, the Logged Measurement Configuration message corresponds to an MDT configuration message.

The UE 200 having received the Logged Measurement

Configuration message is in an idle state, and performs a measurement process of measuring the state of a signal received from the E-UTRAN 10 and recording measurement data (also referred to as "measurement log") including a measurement result. Such a measurement process in the Logged MDT is referred to as a "logging process".

Note that the reception signal state refers to the reference signal received power (RSRP) and reference signal received quality (RSRQ) , for example. In addition to the measurement results of the reception signal state, the measurement data includes the location information during measurement and time information (a time stamp) during measurement . The location information is GPS location information when the UE 200 has a GPS functionality, and is RF fingerprint information when the UE 200 does not have the GPS functionality.

The UE 200 holding the measurement data enters a connected state from the idle state, and then sends the measurement data to the E-UTRAN 10 according to the request of the E-UTRAN 10. The eNB 100 having received the measurement data from the UE 200 transfers the received measurement data to the OAM 320. If the OAM 320 finds a coverage problem based on the measurement data acquired in this way, the OAM 320 performs network optimization for notifying an operator of the found coverage problem or solving the found coverage problem.

As a result of movement, the UE 200 switches the visiting cells. The cell switching performed when the UE 200 is in the connected state is called handover, and the cell switching performed when the UE 200 is in the idle state is called cell reselection. In the mobile communication system 1, one tracking area (TA) includes one or a plurality of cells. The TA denotes an area unit in which location registration and paging are performed.

The MME is configured to manage TA and/or a cell in which the UE 200 stays, and perform different types of mobility management for the UE 200. S-GW is configured to perform transfer control of user data sent and received by the UE 200. The OAM 320 is a server device set up by an operator, and is configured to perform maintenance and monitoring of the E-UTRAN 10. In the present embodiment, the MME/S-G 310 and the OAM 320 correspond to an upper apparatus of a base station.

(Configuration of eNB 100)

Next, a configuration of the eNB 100 is presented. Fig. 2 is a block diagram of the eNB 100.

As shown in Fig. 2, the eNB 100 includes an antenna

101, a radio communication unit 110, a network communication unit 120, a storage unit 130, and a control unit 140.

The antenna 101 is used for sending and receiving radio signals. The radio communication unit 110 is, for example, configured by using a radio frequency (RF) circuit and base band (BB) circuit, and sends and receives radio signals via the antenna 101. The network communication unit 120 is configured to perform communication with other network devices (MME/S-GW 310, OAM 320, and other eNB 100) . The storage unit 130 is, for example, configured by using a memory, and stores different types of information used for controlling the eNB 100. The control unit 140 is, for example, configured by using a processor, and controls different types of functions of the eNB 100.

The control unit 140 includes a configuration message generation unit 141 and a measurement data acquisition processing unit 142.

When the configuration message generation unit 141 determines that the UE 200 is to be used in Logged MDT, the configuration message generation unit 141 generates a Logged Measurement Configuration message , and controls the radio communication unit 110 so as to send the Logged Measurement Configuration message to the corresponding UE 200 in the connected state.

The Logged Measurement Configuration message includes various measurement parameters. The measurement parameter denotes a logging trigger (a measurement trigger), a logging duration (a measurement duration), a network absolute time, a logging area and the like. The logging trigger is used to specify a trigger (an event) by which a logging process is performed. The logging duration is used to specify a duration until the logging process is completed after the measurement parameter is set. The network absolute time serves as a time reference at the UE 200. The logging area is optional and is used to specify a cell or TA in which the logging process is to be performed.

The measurement data acquisition processing unit 142 performs a process of acquiring the measurement data from the UE 200. In the case in which an Availability Indicator indicating that the UE 200 holds the measurement data is received in the radio communication unit 110, when it is determined to acquire the measurement data according to the instruction from the OAM 320 or the determination of the eNB 100 itself, the measurement data acquisition processing unit 142 generates a UE Information Request message for acquiring the measurement data, and controls the radio communication unit 110 such that the UE Information Request message is sent to the UE 200.

The measurement data acquisition processing unit 142 is configured to acquire the measurement data included in the received UE Information Response message when the radio communication unit 110 receives the UE Information Response message sent from the UE 200 in response to the UE Information Request message. Then, the measurement data acquisition processing unit 142 controls the network communication unit 120 so as to transfer the acquired measurement data to the OAM 320. Note that in addition to transferring the measurement data to the OAM 320, the measurement data acquisition processing unit 142 may also interpret the content of the measurement data and use for a parameter adjustment of the eNB 100 itself

(Configuration of UE 200)

Next, the configuration of the UE 200 is explained. Fig. 3 is a block diagram of the UE 200.

As shown in Fig. 3, the UE 200 includes an antenna 201, a radio communication unit 210, a user interface unit 220, a GPS receiver 230, a battery 240, a storage unit 250, and a control unit 260. However, the UE 200 need not include the GPS receiver 230.

The antenna 201 is used for sending and receiving radio signals. The radio communication unit 210 is, for example, configured by using a radio frequency (RF) circuit and a base band (BB) circuit, and sends and receives radio signals via the antenna 201. The user interface unit 220 is a display, a button, or the like that functions as an interface with the user. The battery 240 is a chargeable battery, which accumulates the electric power to be supplied to each block of the UE 200. The storage unit 250 is, for example, configured by using a memory, and stores different types of information used for controlling UE 200. The control unit 260 is, for example, configured by using a processor, and controls different types of functions of the UE 200.

The control unit 260 includes a logging processing unit 261 configured to perform the logging process, a logging control unit 262 configured to control the logging process, a duration timer 263 configured to count the logging duration, a 48-hour timer 264 configured to count 48 hours, and a measurement data management unit 265 configured to manage the measurement data. In the present embodiment, the duration timer 263 corresponds to a first timer and the 48-hour timer 264 corresponds to a second timer.

When the radio communication unit 210 receives the Logged Measurement Configuration message, the logging control unit 262 sets (that is, stores in the storage unit 250) the measurement parameters included in the received Logged Measurement Configuration message, in the connected state. Furthermore, the logging processing unit 261 sets the logging duration, of the measurement parameters, to the duration timer 263, and activates the duration timer 263.

The logging processing unit 261 is in an idle state and performs the logging process according to the measurement parameter stored in the storage unit 250. More particularly, if a trigger specified by the logging trigger, of the measurement parameters, is detected, the logging processing unit 261 measures the reception signal state, and records measurement data including a measurement result, Location information, and time information (i.e., accumulates the measurement data in the storage unit 250) . Here, the Location information included in the measurement data (log) denotes the latest information within a valid time. Furthermore, the time information is generated based on the network absolute time, of the measurement parameters. In addition, when the logging area, of the measurement parameter, has been set, the logging processing unit 261 performs the logging process in a cell or TA specified with the logging area.

The logging control unit 262 activates the duration timer 263 and then monitors the duration timer 263. If the duration timer 263 expires, the logging control unit 262 controls the logging processing unit 261 such that the logging process is ended, releases the setting of the measurement parameter, and activates the 48-hour timer 264.

Furthermore, the logging control unit 262 monitors a battery remaining amount value indicating a remaining amount of the battery 240 during the logging duration. The battery remaining amount value is determined according to a voltage value of the battery 240. In the present embodiment, the battery remaining amount value is a ratio (percentage) of a current voltage value with respect to a maximum voltage value of the battery 240. Since the battery remaining amount value is normally used for the display on a display device included in the user interface 220, it is possible for the logging control unit 262 to relatively easily acquire the battery remaining amount value.

When the battery remaining amount value becomes less than a battery threshold value during the logging duration, the logging control unit 262 performs a control such that the logging process is cancelled. When the battery remaining amount value becomes less than the battery threshold value, the logging control unit 262 forcedly stops the duration timer 263 and activates the 48-hour timer 264.

In addition, the battery threshold value is set to be larger than zero. For example, even when the battery remaining amount value of the battery 240 has reached the battery threshold value, the battery threshold value is preferably set to a value to the extent that at least outgoing and incoming operations of an emergency call are enabled (for a predetermined time). In the present embodiment, it is assumed that the battery threshold value is stored in the storage unit 250 in advance. As described above, since the battery remaining amount value is expressed by the ratio (percentage) of the battery voltage value, the battery threshold value is also expressed by a ratio (percentage) of the battery voltage value. As an example, the battery threshold value may be in the range of about 20% to about 40%.

In this way, using the ratio (percentage) of the battery voltage value, it is possible to appropriately comprehend that the battery remaining amount is reduced, regardless of the type or the aging deterioration of the battery 240.

The measurement data management unit 265 holds the measurement data in the storage unit 250 until the 48-hour timer 264 expires and deletes the measurement data if the 48-hour timer 264 expires, after the expiration of the logging duration or logging cancellation due to the reduction of the battery remaining amount value.

Moreover, when the measurement data is held in the storage unit 250, if a transmission trigger of the Availability Indicator is generated, the measurement data management unit 265 controls the radio communication unit 210 such that the Availability Indicator is transmitted. The transmission trigger of the Availability Indicator denotes transition from an idle state to a connected state (RRC connection establishment), execution of handover (RRC connection re-establishment), and a new setting at an upper layer (RRC re-connection) . For example, when the measurement data is held in the storage unit 250, if the transition from the idle state to the connected state is detected, the measurement data management unit 265 performs a control such that the Availability Indicator, while it is included in an RRC Connection Setup Complete message, is sent to the eNB 100.

If the UE Information Request message sent from the eNB 100 in response to the Availability Indicator is received in the radio communication unit 210, the measurement data management unit 265 acquires the measurement data held in the storage unit 250, and performs a control such that the measurement data, while it is included into the UE Information Response message, is sent to the eNB 100. If the measurement data is sent in this way, the logging control unit 262 deletes the measurement data held in the storage unit 250.

(Operation of UE 200)

Hereinafter, the operation of the UE 200 associated with the Logged MDT will be explained.

First, an operation from the setting of a measurement parameter to a logging completion will be explained. Fig. 4 is an operation flowchart of the UE 200 according to the first embodiment, and illustrates an operation from the setting of the measurement parameter to the logging completion. In the initial state of Fig. 4, it is assumed that the UE 200 is in a connected state.

As illustrated in Fig. 4, in step S101, the radio communication unit 210 receives a Logged Measurement Configuration message from the eNB 100.

In step S102, the logging control unit 262 of the control unit 260 acquires and sets a measurement parameter included in the Logged Measurement Configuration message received in the radio communication unit 210. More particularly, the logging control unit 262 sets the logging duration, of the measurement parameter, to the duration timer 263 and activates the duration timer 263, and stores a remaining measurement parameter in the storage unit 250.

In step S103, the UE 200 enters an idle state and the logging control unit 262 starts a logging process.

In step S104, the logging processing unit 261 checks whether a trigger corresponding to the logging trigger, of the measurement parameters, has occurred. For example, when the logging trigger is "periodic", the logging processing unit 261 checks whether a timing corresponding to a specified cycle has reached. When the logging trigger is a "specific trigger" (e.g., when the reception signal state of a serving cell becomes less than a threshold value) , the logging processing unit 261 checks whether a specified trigger has been occurred. When the trigger corresponding to the logging trigger has not been generated (step S104; NO), the process proceeds to step S106.

When the trigger corresponding to the logging trigger has been occurred (step S104; YES), the logging processing unit 261 measures the reception signal state and stores measurement data, which includes a measurement result, Location information, and time information, in the storage unit 250 in step S105. Then, the process proceeds to step S106.

In step S106, the logging control unit 262 checks whether the duration timer 263 has expired.

When the duration timer 263 has expired (step S106; YES) , in step S107, the logging control unit 262 controls the logging processing unit 261 such that the logging process is completed, and activates the 48-hour timer 264.

Meanwhile, when the duration timer 263 has not expired (step S106; NO), in step S108, the logging control unit 262 checks whether a battery remaining amount value becomes less than a battery threshold value set in advance. When the battery remaining amount value does not become less than the battery threshold value set in advance (step S108; NO), the process returns to step S104.

However, when the battery remaining amount value becomes less than the battery threshold value set in advance (step S108; YES), the logging control unit 262 controls the logging processing unit 261 such that the logging process is cancelled, forcedly stops the duration timer 263, and activates the 48-hour timer 264 in step S109.

Next, an operation after the logging completion/cancellation will be explained. Fig. 5 is an operation flowchart of the UE 200 according to the first embodiment, and illustrates the operation after the logging completion/cancellation.

As illustrated in Fig. 5, in step Sill, the measurement data management unit 265 checks whether the 48-hour timer 264 has expired. When the 48-hour timer 264 has expired (step Sill; YES), in step S112, the measurement data management unit 265 deletes the measurement data held in the storage unit 250.

Meanwhile, when the 48-hour timer 264 has not expired (step Sill; NO) , the measurement data management unit 265 checks whether the transmission trigger of the Availability Indicator has occurred during the current transition to RRC Connected, (Note this assumes the UE can send the Availability Indicator each time it transitions from Idle to Connected) in step S113. When the transmission trigger of the Availability Indicator has not been generated (step S113; NO), the process returns to step Sill.

However, when the transmission trigger of the Availability Indicator has been occurred (step S113; YES), the measurement data management unit 265 controls the radio communication unit 210 such that the Availability Indicator is transmitted to the eNB 100, in step S114. Then, the process proceeds to step S115. In addition, it is highly probable that the eNB 100, which is a transmission destination of the Availability Indicator, is different from the eNB 100 which is a transmission source of the Logged Measurement Configuration message.

In step S115, the measurement data management unit 265 checks whether the radio communication unit 210 has received the UE Information Request message. When the radio communication unit 210 has not received the UE Information Request message (step S115; NO) , the process returns to step Sill.

However, when the radio communication unit 210 has received the UE Information Request message (step S115; YES) , the measurement data management unit 265 acquires the measurement data held in the storage unit 250, and controls the radio communication unit 210 such that the measurement data, while it is included in the UE Information Response message, is sent to the eNB 100, in step S116.

(Summary of first embodiment)

As described above, according to the first embodiment, the UE 200 performs the logging process (the measurement process) with respect to the E-UTRAN 10 according to the Logged Measurement Configuration message, which is received from the E-UTRAN 10, in the Logged MD . During the logging process, when the battery remaining amount value indicating the battery remaining amount of the UE 200 becomes less than the battery threshold value set in advance, the UE 200 cancels the logging process. When the battery remaining amount of the UE 200 is small, if the cancellation of the logging process is enabled, then it is possible to avoid an increase in the power consumption due to the logging process and to prevent the battery remaining amount of the UE 200 from exhausting resulting from the logging process.

[Second embodiment]

Hereinafter, a second embodiment will be explained while focusing on the difference relative to the first embodiment. In the above-mentioned first embodiment, it is described that the battery threshold value is stored in the UE 200 in advance. On the other hand, in the second embodiment, the battery threshold value is specified by a network.

More particularly, the configuration message generation unit 141 of the eNB 100 according to the present embodiment generates a Logged Measurement Configuration message including the battery threshold value as one of the measurement parameters, and controls the radio communication unit 110 such that the Logged Measurement Configuration message is sent to the UE 200 that is in a connected state. The configuration message generation unit 141, for example, may determine the battery threshold value according to an instruction from the OAM 320, or determine the battery threshold value according to its own determination. The battery threshold value, for example, is determined according to the degree of importance of the logging process and the state of the UE 200. For example, a method is considered, in which the eNB 100 (or a network) estimates a release considered to be supported by the UE 200 from UE capability indicating a capability of the UE 200, regards the UE 200 as UE used for many years when it is determined that the UE 200 is UE with an old release, and sets the battery threshold value to be higher than usual (i.e., so that it becomes easier to stop the logging) .

(Operation of UE 200)

Hereinafter, the operation of the UE 200 according to the second embodiment will be explained. Fig. 6 is an operation flowchart of the UE 200 according to the second embodiment, and illustrates an operation from the setting of a measurement parameter to the logging completion. In the initial state of Fig. 6, it is assumed that the UE 200 is in a connected state.

As illustrated in Fig. 6, in step S201, the radio communication unit 210 receives a Logged Measurement Configuration message from the eNB 100. In the present embodiment, the Logged Measurement Configuration message includes a battery threshold value, in addition to the measurement parameters such as the logging trigger (measurement trigger), the logging duration (measurement duration), the network absolute time, and the logging area. Similarly to the first embodiment, the battery threshold value is expressed by the ratio (percentage) of a battery voltage value.

In step S202, the logging control unit 262 of the control unit 260 acquires and sets a measurement parameter included in the Logged Measurement Configuration message received in the radio communication unit 210. More particularly, the logging control unit 262 sets the logging duration, of the measurement parameters, to the duration timer 263 and activates the duration timer 263, and stores a remaining measurement parameter in the storage unit 250.

In step S203, the UE 200 enters an idle state and the logging control unit 262 starts a logging process.

In step S204 , the logging processing unit 261 checks whether a trigger corresponding to the logging trigger, of the measurement parameters, has been occurred. For example, when the logging trigger is "periodic", the logging processing unit 261 checks whether a timing corresponding to a specified cycle has reached. When the logging trigger is a "specific trigger" (e.g., when the reception signal state of a serving cell becomes less than a threshold value) , the logging processing unit 261 checks whether a specified trigger has been occurred. When the trigger corresponding to the logging trigger has not been generated (step S204; NO) , the process proceeds to step S206.

When the trigger corresponding to the logging trigger has been occurred (step S204; YES), the logging processing unit 261 measures the reception signal state, acquires Location information and time information, and stores measurement data, which includes the measurement result, the Location information, and the time information, in the storage unit 250, in step S205. Then, the process proceeds to step S206. In step S206, the logging control unit 262 checks whether the duration timer 263 has expired.

When the duration timer 263 has expired (step S206; YES), the logging control unit 262 controls the logging processing unit 261 such that the logging process is completed, and activates the 48-hour timer 264 in step S207.

Meanwhile, when the duration timer 263 has not expired (step S206; NO), the logging control unit 262 checks whether a battery remaining amount value becomes less than the battery threshold value, of the measurement parameters, in step S208. When the battery remaining amount value does not become less than the battery threshold value, of the measurement parameters (step S208; NO), the process returns to step S204.

However, when the battery remaining amount value becomes less than the battery threshold value, of the measurement parameters (step S208; YES), in step S209, the logging control unit 262 controls the logging processing unit 261 such that the logging process is cancelled, forcedly stops the duration timer 263, and activates the 48-hour timer 264.

Note that the operation of the UE 200 after the logging completion/cancellation is performed in the same manner as in the first embodiment.

(Summary of second embodiment)

As described above, according to the second embodiment, the UE 200 performs the logging process (the measurement process) with respect to the E-UTRAN 10 according to the Logged Measurement Configuration message, which is received from the E-UTRAN 10, in the Logged MDT . During the logging process, when the battery remaining amount value indicating the battery remaining amount of the UE- 200 becomes less than the battery threshold value specified by the Measurement Configuration message, the UE 200 cancels the logging process. When the battery remaining amount of the UE 200 is small, if cancellation of the logging process is enabled, then it is possible to avoid an increase in the power consumption due to the logging process and to prevent the battery remaining amount of the UE 200 from exhausting resulting from the logging process. Furthermore, when the battery threshold value can be specified by the network, it is possible to appropriately set the battery threshold value according to the degree of importance of the logging process, the state of the UE 200, and the like.

[Modified example of Second embodiment]

Other than the network configuring a batter threshold value to the UE 200, could there also be a possibility that the standard would set a default battery threshold such that in the absence of configured battery threshold the UE 200 will use the default battery threshold. For example, if the first and second embodiments are concomitantly-used, two types of battery threshold values exist in the UE200.

Another thing we might consider is the idea that there could be both a UE' s internally specified battery threshold (UE implementation) that is lower than a network specified battery threshold. The idea is that if the battery level is lower than the network configured battery threshold but higher than UE' s internal battery threshold, the logging may continue. This means when the network specified battery threshold is triggered, the UE is allowed to stop logging but is not required to stop logging depending on UE implementation.

[Third embodiment]

Hereinafter, a third embodiment will be explained while focusing on the difference relative to the first embodiment. In the above-mentioned first embodiment, when the battery remaining amount value becomes less than the battery threshold value, the UE 200 cancels the logging process. On the other hand, in the third embodiment, when the battery remaining amount value becomes less than the battery threshold value, the configuration is such that the UE 200 can determine whether to cancel the logging process .

More particularly, the configuration message generation unit 141 of the eNB 100 according to the present embodiment generates a Logged Measurement Configuration message including specific information for determining whether to permit the cancellation of the logging process, and controls the radio communication unit 110 such that the Logged Measurement Configuration message is sent to the UE 200 in a connected state. In the present embodiment, the specific information denotes information (hereinafter, referred to as "Trace information") indicating a network entity that has determined to cause the UE 200 to perform the logging process. In other words, the Trace information indicates a network entity having selected the UE 200 in which logging process should be performed.

In the present embodiment, the eNB 100 and the OAM 320 have a determination right for the UE 200 to perform the logging process. However, MME may have the determination right for the UE 200 to perform the logging process.

As compared with the case in which the eNB 100 determines the UE 200 which is to perform the logging process, when an upper apparatus (i.e., the OAM 320, the MME and the like) of the eNB 100 determines the UE 200 which is to perform the logging process, the degree of importance of the logging process is higher. This is because the upper apparatus of the eNB 100 can know more information than information which can be known by the eNB 100, and can sufficiently reflect the will of an operator. As an example, the Trace information is configured by a 1-bit flag in which "1" is used when the eNB 100 determines the UE 200 which is to perform the logging process, and "0" is used when the upper apparatus of the eNB 100 determines the UE 200 which is to perform the logging process.

A method by which the eNB 100 determines the UE 200 which is to perform the logging process will be referred to as a Management based trace procedure. A UE selection in the Management based trace procedure is performed based on information received in RAN (eNB) from EM, and (MDT) consent information of a user preserved in the eNB. Here, the EM (Element Manager) manages each device (element) configuring the network.

A method by which the upper apparatus of the eNB 100 determines the UE 200 which is to perform the logging process will be referred to as a Signaling based trace procedure. A UE selection in the Signaling based trace procedure is performed by an IMSI/IMEI (SV) -based UE selection, or a UE selection obtained by combining the IMSI/IMEI (SV) with area information. That is, this is as if a UE measurement activation is performed by extending an EPC trace activation procedure.

In addition, see the 3GPP TS 32.422 for details of the Management based trace procedure and the Signaling based trace procedure.

(Operation of UE 200)

Hereinafter, the operation of the UE 200 according to a third embodiment will be explained. Fig. 7 is an operation flowchart of the UE 200 according to the third embodiment, and illustrates an operation from the setting of . a measurement parameter to the logging completion. In the initial state of Fig. 7, it is assumed that the UE 200 is in a connected state. In addition, similarly to the first embodiment, in the present embodiment, an example will be explained, in which a battery threshold value is stored in the UE 200 in advance. However, similarly to the second embodiment, the battery threshold value may be specified by the network.

As illustrated in Fig. 7, in step S301, the radio communication unit 210 receives a Logged Measurement Configuration message from the eNB 100. In the present embodiment, the Logged Measurement Configuration message includes the above-mentioned Trace information in addition to the measurement parameters such as a logging trigger (measurement trigger), a logging duration (measurement duration) , a network absolute time, and a logging area.

In step S302, the logging control unit 262 of the control unit 260 acquires and sets a measurement parameter included in the Logged Measurement Configuration message received in the radio communication unit 210. More particularly, the logging control unit 262 sets the logging duration, of the measurement parameters, to the duration timer 263 and activates the duration timer 263, and stores a remaining measurement parameter in the storage unit 250. Furthermore, the logging control unit 262 stores the Trace information, which is included in the Logged Measurement Configuration message, in the storage unit 250.

In step S303, the UE 200 enters an idle state and the logging control unit 262 starts a logging process.

In step S304, the logging processing unit 261 checks whether a trigger corresponding to the logging trigger, of the measurement parameters, has been occurred. For example, when the logging trigger is "periodic", the logging processing unit 261 checks whether a timing cor esponding to a specified cycle has reached. When the logging trigger is a "specific trigger" (e.g., when the reception signal state of a serving cell becomes less than a threshold value) , the logging processing unit 261 checks whether a specified trigger has been occurred. When the trigger corresponding to the logging trigger has not been generated (step S304 ; NO) , the process proceeds to step S306.

When the trigger corresponding to the logging trigger has been occurred (step S304 ; YES) , the logging processing unit 261 measures the reception signal state, acquires Location information and time information, and stores measurement data, which includes a measurement result, the Location information, and the time information, in the storage unit 250, in step S305. Then, the process proceeds to step S306.

In step S306, the logging control unit 262 checks whether the duration timer 263 has expired.

When the duration timer 263 has expired (step S306;

YES), the logging control unit 262 controls the logging processing unit 261 such that the logging process is completed, and activates the 48-hour timer 264, in step S307.

Meanwhile, when the duration timer 263 has not expired (step S306; NO), the logging control unit 262 checks whether a battery remaining amount value becomes less than a battery threshold value set in advance, in step S308. When the battery remaining amount value does not become less than the battery threshold value set in advance (step S308; NO), the process returns to step S304.

However, when the battery remaining amount value becomes less than the battery threshold value set in advance (step S308; YES), the logging control unit 262 checks whether the Trace information indicates the eNB 100, in step S309. When the Trace information indicates the upper apparatus of the eNB 100 (step S309; NO), the process returns to step S304.

On the other hand, when the Trace information indicates the eNB 100 (step S309; YES), the logging control unit 262 controls the logging processing unit 261 such that the logging process is cancelled, forcedly stops the duration timer 263, and activates the 48-hour timer 264, in step S310.

(Summary of third embodiment)

As described above, according to the third embodiment, during the logging process, when the battery remaining amount value becomes less than the battery threshold value and it is determined that the cancellation of the logging process is permitted based on the Trace information (i.e. , the network entity having determined to cause the UE 200 to perform the logging process is the eNB 100), the UE 200 cancels the logging process .

On the other hand, during the logging process, although the battery remaining amount value becomes less than the battery threshold value, when it is determined that the cancellation of the logging process is not permitted based on the Trace information (i.e., when the network entity having determined to cause the UE 200 to perform the logging process is the upper apparatus of the eNB 100), the UE 200 continues the logging process without cancelling the logging process.

In this way, when the battery remaining amount of the UE 200 is small, it is possible to determine whether to cancel the logging process in consideration of the degree of importance of the logging process.

[Fourth embodiment]

Hereinafter, a fourth embodiment will be explained while focusing on the difference relative to the first embodiment. In the fourth embodiment, the operation of the mobile communication system 1 after the logging completion/cancellation is different from that of the first embodiment. In the present embodiment, when a logging process is cancelled because a battery remaining amount value becomes less than a battery threshold value, the UE 200 stores the cancellation.

(Operation of mobile communication system)

Fig. 8 is an operation sequence diagram of the mobile communication system 1 according to the fourth embodiment, and illustrates an operation after the UE 200 completes /cancels the logging process.

In step S401, the measurement data management unit

265 of the UE 200 checks whether a transmission trigger of Availability Indicator has been occurred in the current transition to RRC Connected. When the transmission trigger of the Availability Indicator has been occurred (step S401; YES), the process proceeds to step S402.

In step S402, the measurement data management unit

265 of the UE 200 checks whether measurement data is held in the storage unit 250. When the measurement data is held in the storage unit 250 (step S402; YES) , the process proceeds to step S403.

In step S403, the measurement data management unit

265 of the UE 200 controls the radio communication unit 210 such that the Availability Indicator is sent to the eNB 100 which is a connection destination. The radio communication unit 110 of the eNB 100 receives the Availability Indicator from the UE 200.

In step S404, the measurement data acquisition processing unit 142 of the eNB 100 determines whether to acquire the measurement data held by the UE 200. When it is determined to acquire the measurement data (step S404; YES), the process proceeds to step S405,

In step S405, the measurement data acquisition processing unit 142 of the eNB 100 controls the radio communication unit 110 such that a UE Information Request message for acquiring the measurement data is sent to the UE 200. The radio communication unit 210 of the UE 200 receives the UE Information Request message from the eNB 100.

In step S406, the measurement data management unit 265 of the UE 200 acquires the measurement data held by the storage unit 250 and includes the measurement data in the UE Information Response message.

In step S407, the measurement data management unit 265 of the UE 200 checks whether the logging process has been cancelled because a battery remaining amount value becomes less than a battery threshold value (hereinafter, simply referred to as "battery reduction") . When the logging process has cancelled due to the battery reduction (step S407 ; YES) , the process proceeds to step S408. On the other hand, when the logging process has not been cancelled due to the battery reduction (step S407; NO), the process proceeds to step S409.

In step S408, the measurement data management unit

265 of the UE 200 includes cancellation information, which indicates that the logging process has been cancelled due to the battery reduction, in the UE Information Response message.

In step S409, the measurement data management unit

265 of the UE 200 controls the radio communication unit 210 such that the UE Information Response message is sent to the eNB 100 which is a connection destination. The radio communication unit 110 of the eNB 100 receives the UE Information Response message from the UE 200.

In step S410, the measurement data acquisition processing unit 142 of the eNB 100 checks whether the cancellation information is included in the UE Information Response message. When the cancellation information is included in the UE Information Response message (step S410; YES), the process proceeds to step S411.

In step S411, the configuration message generation unit 141 of the eNB 100 regulates the transmission of an MDT Configuration message to the UE 200. In the present embodiment, the configuration message generation unit 141 performs a control such that a Logged Measurement Configuration message is not sent to the UE 200.

Furthermore, in step S411, the measurement data acquisition processing unit 142 of the eNB 100 controls the network communication unit 120 such that the cancellation information is shared by another network entity. For example, the measurement data acquisition processing unit 142 controls the network communication unit 120 such that the cancellation information or information based on the cancellation information is sent to another eNB 100 on an X2 interface. Otherwise, the measurement data acquisition processing unit 142 controls the network communication unit 120 such that the cancellation information or the information based on the cancellation information is sent to an upper apparatus on an SI interface. In addition, when the cancellation information or the information based on the cancellation information is notified to another network entity, it is preferable that identification information on the UE 200 is also notified.

(Summary of fourth embodiment)

As described above, according to the fourth embodiment, after the logging process is cancelled due to the battery reduction, the UE 200 sends the UE Information Response message, while being included in the E-UTRAN 10, including the cancellation information indicating that the logging process has been cancelled due to the battery reduction, to the eNB- 100 (the E-UTRAN 10) . In this way, the eNB 100 (the E-UTRAN 10) can comprehend that the UE 200 is in a battery reduction state.

Furthermore, when the cancellation information is included in the UE Information Response message from the UE 200, the eNB 100 (the E-UTRAN 10) regulates the transmission of the MDT Configuration message to the UE 200. In this way, it is possible to prevent the MDT from being configured for the UE 200 that is in the battery reduction state.

Moreover, when the cancellation information is included in the UE Information Response message from the UE 200, the eNB 100 (the E-UTRAN 10) notifies another network entity included in the E-UTRAN 10 of the cancellation information or information based on the cancellation information. In this way, another network entity can comprehend that the UE 200 is in the battery reduction state. As a consequence, after the UE 200 sends the UE Information Response message including the cancellation information, although the UE 200 has performed handover, it is possible to prevent the MDT from being configured in a handover destination. [Modified example of Forth embodiment]

In the forth embodiment, if the battery remaining amount value exceeds the battery threshold value by charging the battery after the UE 200 sends the UE Information Response message including the cancellation information, it becomes possible to configure MDT to the UE 200.

In this Modified example, the UE 200 indicates to the network that the battery has been charged. The UE 200 may indicate to the network that the battery remaining amount value exceeds the battery threshold value. For example, the UE 200 sends such indication when availability indicator transmission trigger is occurred. As a result, new MDT can be configured to the UE once again.

Or perhaps this can be left to network implementation e.g., wait a couple of days before configuring the UE. In this case, the network activates a timer after receiving the UE Information Response message including the cancellation information from the UE 200, and regrates new MDT configuration to the UE200 before the timer expires. Then, the network is allowed to configure new MDT after the timer expires.

[Other embodiments]

While the present invention has been described by way of the foregoing embodiments, as described above, it should not be understood that the statements and drawings forming part of this disclosure limits the invention. Further, various substitutions, examples or operational techniques shall be apparent to a person skilled in the art based on this disclosure.

For example, the above-mentioned embodiments are not limited to the case in which they are embodied separately and independently. That is, the above-mentioned embodiments may be embodied through a combination thereof.

In the above-mentioned third embodiment, the specific information for determining whether to permit the cancellation of the logging process denotes the Trace information indicating a network entity having determined to cause the UE 200 to perform the logging process. However, information directly indicating whether to permit the cancellation of the logging process may be set as the specific information. In such a case, the specific information may also be set as a 1-bit flag, for example, in which "1" is used when the cancellation of the logging process is permitted, and "0" is used when the cancellation of the logging process is not permitted.

In the above-mentioned embodiments, an example has been explained, in which the present invention is applied to the Logged MDT in Idle that is Logged MDT of a mode in which the logging process is performed by the UE 200 in an idle state. However, the present invention may also be applied to Logged MDT in Connected that is Logged MDT of a mode in which the logging process is performed by the UE 200 in a connected state. Moreover, the present invention is not limited to the Logged MDT. For example, the present invention may also be applied to Immediate MDT. According to the Immediate MDT, the UE 200 in the connected state performs the measurement, and immediately reports (sends) the measurement data including a measurement result to a network (see the 3GPP TS 37.320 vlO .1.0) .

Furthermore, in each embodiment described above, the mobile communication system configured based on LTE was explained, however, in addition to LTE, the present invention may also be applied to another mobile communication system supporting MDT (for example, -CDMA) .

Thus, it must be understood that the present invention includes various embodiments that are not described herein .

Note that the entire disclosure of U.S. Provisional Application No. 61/389394 (filed on October 4, 2010) is incorporated into the present specification by reference.

INDUSTRIAL APPLI CABILITY As described above, in accordance with the measurement control method and the radio terminal according to the present invention, it is possible to correct an adverse effect caused by an increase in power consumption due to MDT, so that the measurement control method and the radio terminal are useful for radio communication such as mobile communication.

Claims

[Claim 1]

A measurement control method in a mobile communication system including a radio terminal which supports MDT defined in a 3GPP standard, and a network which communicates with the radio terminal, the measurement control method comprising:

a step in which the radio terminal performs a measurement process with respect to the network, according to an MDT configuration message received from the network; and

a step in which when a battery remaining amount value indicating a battery remaining amount of the radio terminal becomes less than a battery threshold value during the measurement process, the radio terminal cancels the measurement process .

[Claim 2]

The measurement control method according to claim 1, wherein the measurement process includes a process for recording a measurement result in addition to a process for measuring a reception signal state.

[Claim 3]

The measurement control method according to claim 2, wherein, in the step of performing the measurement process, in an idle state, the radio terminal performs the measurement process according to the MDT configuration message .

[Claim 4]

The measurement control method according to claim 2, wherein

the MDT configuration message includes information specifying a measurement duration that is a duration from a measurement parameter included in the MDT configuration message is set to the radio terminal until the measurement process is completed, and

the step of cancelling includes a step of stopping a first timer configured to count the measurement duration.

[Claim 5]

The measurement control method according to claim 2, wherein

the radio terminal is configured to hold the recorded measurement result until a predetermined time lapses after the measurement process is completed, and

the step of cancelling includes a step of activating a second timer configured to count the predetermined time.

[Claim 6]

The measurement control method according to claim 1, wherein the battery remaining amount value is determined according to a voltage value of a battery provided in the radio terminal.

[Claim 7]

The measurement control method according to claim 6, wherein the battery remaining amount value indicates a ratio of a current voltage value with respect to a maximum voltage value of the battery.

[Claim 8]

The measurement control method according to claim 1, wherein the battery threshold value is set to a value larger than zero.

[Claim 9]

The measurement control method according to claim 1, wherein the battery threshold value is set in the radio terminal in advance.

[Claim 10]

The measurement control method according to claim 1, wherein the MDT configuration message includes information specifying the battery threshold value.

[Claim 11]

The measurement control method according to claim 1, wherein

the MDT configuration message includes specific information used for determining whether to permit cancellation of the measurement process, and

in the step of cancelling, when the battery remaining amount value becomes less than the battery threshold value and it is determined that the cancellation of the measurement process is permitted based on the specific information during the measurement process, the radio terminal cancels the measurement process.

[Claim 12]

The measurement control method according to claim 11, wherein

the specific information indicates a network entity having determined to cause the radio terminal to perform the measurement process, and

when the determined network entity is a base station, it is determined that the cancellation of the measurement process is permitted.

[Claim 13]

The measurement control method according to claim 11, wherein

the radio terminal further comprises a step of continuing the measurement process without cancelling the measurement process, when it is determined that the cancellation of the measurement process is not permitted based on the specific information, during the measurement process and even when the battery remaining amount value becomes less than the battery threshold value.

[Claim 14]

The measurement control method according to claim 13, wherein

when the determined network entity is an upper apparatus of a base station, it is determined that the cancellation of the measurement process is not permitted.

[Claim 15]

The measurement control method according to claim 1, further comprising a step of sending a message used for sending measurement data obtained by the measurement process, to the network from the radio terminal, wherein after the measurement process is cancelled in the step of cancelling, the radio terminal sends predetermined information on cancellation of the measurement process, while the predetermined information is included in the message, in the step of sending the message.

[Claim 16]

The measurement control method according to claim 15, wherein the predetermined information indicates that the measurement process is cancelled because the battery remaining amount value becomes less than the battery threshold value.

[Claim 17]

The measurement control method according to claim 15, further comprising a step in which the network controls transmission of the MDT configuration message to the radio terminal based on the predetermined information included in the message from the radio terminal.

[Claim 18]

The measurement control method according to claim 17, wherein the step of controlling includes a step in which when cancellation information is included in the message from the radio terminal, the network regulates the transmission of the MDT configuration message to the radio terminal.

[Claim 19]

The measurement control method according to claim 17, wherein the step of controlling further comprises a step in which when cancellation information is included in the message from the radio terminal, the network shares the cancellation information between network entities included in the network. [Claim 20]

A radio terminal which supports MDT defined in a 3GPP standard, the radio terminal comprising:

a measurement processing unit configured to perform a measurement process with respect to a network, according to an MDT configuration message received from the network; and

a measurement control unit configured to cancel the measurement process when a battery remaining amount value indicating a battery remaining amount of the radio terminal becomes less than a battery threshold value during the measurement process.