Terminal device, control method, and program for improving efficiency of communication using multiple carrier waves

Abstract

To improve the efficiency of communication that uses multiple carrier waves.SOLUTION: A terminal device that executes control related to dual connectivity or carrier aggregation provides a base station device with first information for identifying a communication circuit of the terminal device, and second information related to a first received power of a first carrier wave and a second received power of a second carrier wave regarding the first carrier wave and the second carrier wave used for dual connectivity or carrier aggregation.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to wireless communication technology using a plurality of carrier waves.

Background Art

[0002] In the 3rd Generation Partnership Project (3GPP), mechanisms for dual connectivity and carrier aggregation are defined, in which a terminal device communicates using a plurality of carrier waves (component carriers).

Summary of the Invention

Problems to be Solved by the Invention

[0003] A terminal device can process communication using a plurality of carrier waves within the same band, for example, by a single communication circuit. In this case, when the difference value of the received power for each of the plurality of carrier waves is large, for example, in communication using the carrier wave with the lower received power, sufficient throughput may not be obtained, and the communication efficiency may become insufficient.

Means for Solving the Problems

[0004] The present invention provides a technique for improving the efficiency of communication using a plurality of carrier waves.

[0005] A terminal device according to an aspect of the present invention includes control means for executing control related to dual connectivity or carrier aggregation, and providing means for providing, to a base station device, first information for identifying a communication circuit of the terminal device, and second information regarding a first received power of the first carrier wave and a second received power of the second carrier wave for the first carrier wave and the second carrier wave used for the dual connectivity or the carrier aggregation.

Effects of the Invention

[0006] According to the present invention, the efficiency of communication using a plurality of carrier waves can be improved.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims, and not all combinations of the features described in the embodiments are essential for the invention. Two or more of the features described in the embodiments may be arbitrarily combined. Also, the same or similar configurations are given the same reference numerals, and redundant descriptions are omitted.

[0009] (Network Configuration) FIG. 1 shows a configuration example of the network according to the present embodiment. This network is, for example, a cellular radio communication network in which radio communication compliant with the Long-Term Evolution (LTE) or New Radio (NR) standard of the 3rd Generation Partnership Project (3GPP) is performed. This network is configured to include, for example, a base station device 101 and a terminal device 111. In the present embodiment, the terminal device 111 is configured to be able to execute communication using dual connectivity (DC) or carrier aggregation (CA), which is defined as a mechanism for using a plurality of carriers (component carriers) in parallel. In FIG. 1, an example is shown in which the terminal device 111 communicates using two carriers, a first carrier (CC1) and a second carrier (CC2). Note that the communication by the first carrier and the second carrier may both be provided by the base station device 101, or may be configured such that the base station device 101 provides communication by the first carrier and another base station device 102 provides communication by the second carrier. Further, the terminal device 111 may be configured to communicate using three or more carriers in parallel. In one example, the base station device 101 may be a base station device operating in compliance with the NR standard, and the base station device 102 may be a base station device operating in compliance with the LTE standard. The terminal device 111 can communicate, for example, using a first carrier associated with LTE and a second carrier associated with NR in parallel. Further, the terminal device 111 can communicate, for example, using a first carrier and a second carrier both associated with NR in parallel.

[0010] The terminal device 111 can execute reception processing of two or more carrier waves using, for example, one communication circuit. In this case, for example, when the difference value between the first received power related to the first carrier wave and the second received power related to the second carrier wave exceeds a certain value, the communication throughput in the carrier wave with the lower received power may become insufficient. For example, according to 3GPP's TS38.101, it is required as the performance of the terminal device that when the first received power is 6 dB higher than the second received power, the throughput of the second carrier wave can achieve 85% of the maximum throughput. Therefore, when the second received power is even lower, for example, it is assumed that the throughput further decreases. Thus, the efficiency of communication using a plurality of carrier waves decreases due to the decrease in throughput caused by an increase in the difference value between the first received power and the second received power.

[0011] In this embodiment, in view of such circumstances, a technique for improving the efficiency of wireless communication (for example, DC or CA) using a plurality of carrier waves in parallel is provided.

[0012] The base station device 101 of this embodiment acquires, for example, information related to the first received power related to the first carrier wave and the second received power related to the second carrier wave in the terminal device 111 from the terminal device 111, and based on that information, determines whether to cause the terminal device 111 to execute DC or CA.

[0013] When the terminal device 111 is not performing communication by DC or CA, the base station device 101 determines whether or not the difference value between the first received power and the second received power exceeds a predetermined value, and based on the determination that the difference value does not exceed the predetermined value, can control to start communication by DC or CA for the terminal device 111. In the terminal device 111, when the received power difference between the first received power in the first carrier currently used for communication and the second received power in the second carrier available for communication by DC or CA is sufficiently small, the terminal device 111 can perform communication by DC or CA without an extreme decrease in throughput. That is, the situation where the received power difference is sufficiently small can be said to be a situation where the terminal device 111 can perform sufficiently efficient communication when using the second carrier as a secondary cell for communication. Therefore, the base station device 101 can determine to start communication by DC or CA for the terminal device 111 on the condition that the difference value between the first received power and the second received power does not exceed a predetermined value. Note that when the terminal device 111 should not perform communication by DC or CA, the base station device 101 does not have to start communication by DC or CA for the terminal device 111 even if the difference value between the first received power and the second received power does not exceed a predetermined value. That is, the condition for starting communication by DC or CA for the terminal device 111 is that the difference value between the first received power and the second received power does not exceed a predetermined value, and even if this condition is satisfied, communication by DC or CA does not have to be started.

[0014] Note that when there are a plurality of carriers in the terminal device 111 that can perform sufficiently efficient communication when used as a secondary cell, the base station device 101 may determine the carriers to be used in DC or CA according to the load status of the base station device that provides communication on those carriers. For example, the base station device 101 obtains from the terminal device 111 not only information that can specify a first difference value between a first received power of a first carrier and a second received power of a second carrier in the terminal device 111, but also information that can specify a second difference value between the first received power and a third received power of a third carrier. Then, when the base station device 101 determines that both the first difference value and the second difference value do not exceed a predetermined value, based on the load of the base station device that provides communication using the second carrier and the load of the base station device that provides communication using the third carrier, it determines which of the second carrier and the third carrier should be used. For example, when the load of the base station device that provides communication using the second carrier is lower than the load of the base station device that provides communication using the third carrier, the second carrier can be used as a secondary cell. Also, when the load of the base station device that provides communication using the third carrier is lower than the load of the base station device that provides communication using the second carrier, the third carrier can be used as a secondary cell. Note that when both the load of the base station device that provides communication using the second carrier and the load of the base station device that provides communication using the third carrier are sufficiently low, for example, the smaller one of the above-described first difference value and second difference value may be used. That is, when the first difference value is smaller than the second difference value, the second carrier is used as a secondary cell, and when the second difference value is smaller than the first difference value, the third carrier can be used as a secondary cell. Note that when the terminal device 111 can use three or more carriers in parallel, the base station device 101 may execute control to cause the terminal device 111 to perform communication by DC or CA using both the second carrier and the third carrier.

[0015] Further, when the base station apparatus 101 determines that the difference value between the first received power and the second received power exceeds a predetermined value while the terminal apparatus 111 is performing communication by DC or CA using the first carrier wave and the second carrier wave, the base station apparatus 101 can control the terminal apparatus 111 to terminate the communication. In the terminal apparatus 111, when the received power difference between the first received power and the second received power becomes large during communication by DC or CA using the first carrier wave and the second carrier wave, it is expected that the communication efficiency will decrease. Therefore, the base station apparatus 101 performs control such that communication by DC or CA (for example, communication by a secondary cell) ends.

[0016] Note that the base station apparatus 101 may only perform the start process of communication by DC or CA as described above, and may not execute the end process of communication by DC or CA. Further, the base station apparatus 101 may only execute the end process of communication by DC or CA, and may not perform the start process of communication by DC or CA as described above. Further, the base station apparatus 101 may execute both of these processes. Further, for example, in the above-described process, the base station apparatus 101 may allow the start of communication by DC or CA based on the state where the difference value of the received power does not exceed the predetermined value continuing for a predetermined time. Similarly, in the above-described process, when the state where the difference value of the received power exceeds the predetermined value continues for a predetermined time, the base station apparatus 101 can control to terminate the ongoing communication by DC or CA. Note that, for example, in a conventional standard, an event for performing a measurement report of the radio quality between a connected cell and its adjacent cell is defined in response to the radio quality of adjacent cells with different radio access technologies (RAT) becoming equal to or higher than a predetermined value. The base station apparatus 101 may, at this time, identify the difference value of the received power between the first carrier wave and the second carrier wave based on the measurement report, and execute the above-described process based on the difference value.

[0017] In the terminal device 111, a difference value between the first received power of the first carrier wave and the second received power of the second carrier wave may be calculated. In this case, the base station device 101 notifies the terminal device 111 of, for example, the above-described predetermined value. The base station device 101 may notify the terminal device 111 of this predetermined value in association with a condition for reporting at least any one of the above-described various types of information. When the terminal device 111 determines that the notified condition is satisfied, it can report at least any one of the above-described various types of information. In one example, the base station device 101 may notify that the difference value between the first received power and the second received power exceeds a predetermined value as a condition. Note that this condition may be notified, for example, when the terminal device 111 is already performing communication by DC or CA. For example, if the first carrier wave is the carrier wave of the master cell and the second carrier wave is the carrier wave of the secondary cell, the terminal device 111 can transmit a predetermined report to the base station device 101 when the difference value obtained by subtracting the second received power from the first received power exceeds a predetermined value. Further, the base station device 101 may notify that the difference value between the first received power and the second received power does not exceed a predetermined value as a condition. Note that this condition may be notified, for example, when the terminal device 111 is not performing communication by DC or CA. The terminal device 111 can transmit a predetermined report to the base station device 101 when the difference value obtained by subtracting the received power of the second carrier wave corresponding to a candidate of the surrounding secondary cell from the received power of the first carrier wave associated with the cell being connected does not exceed a predetermined value. Further, the base station device 101 may notify, for example, the value of a timer to be set in the terminal device 111. In this case, when the calculated difference value exceeds (or falls below) a predetermined value, the terminal device 111 starts the timer, and may transmit a report to the base station device 101 in response to the timer expiring while that state is maintained. In the report here, for example, information indicating the difference value may be notified. In the report here, any information that can specify whether the difference value exceeds a predetermined value, such as information indicating that the difference value exceeds a predetermined value or does not exceed a predetermined value, may be notified. Note that the terminal device 111 may report information indicating the first received power and information indicating the second received power to the base station device 101.

[0018] Note that the terminal device 111 may have a plurality of communication circuits. In this case, the terminal device 111 can be configured to process, for example, a first carrier wave by a first communication circuit and a second carrier wave by a second communication circuit. When a plurality of communication circuits can be used in this way, even if the difference value between the first received power of the first carrier wave and the second received power of the second carrier wave is relatively large, it may be possible to perform communication without a significant decrease in throughput. That is, when processing a plurality of carrier waves in one communication circuit, if the power difference is large, the signal of the carrier wave with low power may be buried due to insufficient dynamic range of the communication circuit. However, when separate communication circuits are used, the influence of other carrier waves other than the carrier waves processed by the communication circuit can be suppressed, so quality degradation due to the dynamic range is less likely to occur. However, for example, for a carrier wave with low power, the influence of power leakage from other carrier waves may become non-negligible in some cases. Therefore, even when processing a plurality of carrier waves by separate communication circuits, communication by DC or CA can be performed on the condition that the power difference does not exceed a predetermined value. However, the first predetermined value when a plurality of carrier waves are processed by one communication circuit and the second predetermined value when a plurality of carrier waves are processed by separate communication circuits can be set separately. Here, for example, the first predetermined value can be set smaller than the second predetermined value. That is, when a plurality of carrier waves are processed by one communication circuit, communication by DC or CA is allowed on the condition that the power difference between the first carrier wave and the second carrier wave is sufficiently small. When a plurality of carrier waves are processed by separate communication circuits, communication by DC or CA can be allowed even if the power difference is larger than the first predetermined value.

[0019] Note that the base station apparatus 101 can acquire, for example, from the terminal apparatus 111, information indicating whether the terminal apparatus 111 executes processing of a plurality of carriers by one communication circuit or executes processing of a plurality of carriers using separate communication circuits for each. Note that this information may be, for example, information indicating the number of communication circuits included in the terminal apparatus 111.

[0020] Note that an example has been described in which the base station apparatus 101 controls communication using dual connectivity or carrier aggregation in the terminal apparatus 111 based on the magnitude of the difference value of the received power in the terminal apparatus 111, but the present invention is not limited thereto. That is, any network node including the base station apparatus 101 may be configured to execute the above-described processing.

[0021] (Device Configuration) FIG. 2 is a diagram showing an example of the hardware configuration of the base station apparatus 101. In one example, the base station apparatus 101 includes a processor 201, a ROM 202, a RAM 203, a storage device 204, and a communication circuit 205. The processor 201 is a computer including one or more processing circuits such as a general-purpose CPU (Central Processing Unit) or an ASIC (Application Specific Integrated Circuit), and reads and executes programs stored in the ROM 202 and the storage device 204 to execute the overall processing of the apparatus and each of the above-described processes. The ROM 202 is a read-only memory that stores information such as programs and various parameters related to the processing executed by the base station apparatus 101. The RAM 203 functions as a workspace when the processor 201 executes a program, and is a random access memory that stores temporary information. The storage device 204 is configured by, for example, a removable external storage device or the like. The communication circuit 205 is configured by, for example, a circuit for LTE or 5G wireless communication. Note that in FIG. 2, one communication circuit 205 is illustrated, but the base station apparatus 101 may have a plurality of communication circuits. For example, the base station apparatus 101 may have a communication circuit for wired communication with another base station apparatus (for example, the base station apparatus 102).

[0022] FIG. 3 is a diagram showing a functional configuration example of the base station apparatus 101. The base station apparatus 101 includes, for example, an information acquisition unit 301, a determination unit 302, a control unit 303, a setting unit 304, and a condition notification unit 305. Note that these functional units can be implemented, for example, when the processor 201 executes programs stored in the ROM 202 and the storage device 204. However, the implementation is not limited thereto, and for example, some or all of these functional units may be implemented using dedicated hardware. Since the processing to be executed by the base station apparatus 101 has been described above, here, only a rough overview of the functional configuration of the base station apparatus 101 will be given.

[0023] The information acquisition unit 301 acquires information regarding a first received power obtained by measuring a first carrier wave corresponding to a cell to which the terminal device 111 is currently connected, and a second received power obtained by measuring a second carrier wave corresponding to a secondary cell in use or a candidate for an available secondary cell in communication by DC or CA. Note that this information may include information indicating the first received power and information indicating the second received power. Further, this information may include information indicating a difference value between the first received power and the second received power. Further, this information may include information capable of specifying whether or not the difference value between the first received power and the second received power exceeds a predetermined value. Note that, in addition to the first carrier wave corresponding to the connected cell, the information acquisition unit 301 may acquire information regarding the received powers of two or more other carrier waves (for example, the second carrier wave and the third carrier wave). Further, the information acquisition unit 301 may acquire, from the terminal device 111, information indicating whether the terminal device 111 processes a plurality of carrier waves using one communication circuit or processes each using a separate communication circuit, for example.

[0024] The determination unit 302 determines whether or not a difference value between the first received power and the second received power exceeds a predetermined value based on the information acquired by the information acquisition unit 301. Further, when the information acquisition unit 301 acquires information regarding the third received power, for example, the determination unit 302 may determine whether or not a difference value between the first received power and the third received power exceeds a predetermined value.

[0025] Based on the result of the determination by the determination unit 302, the control unit 303 executes control regarding communication by DC or CA of the terminal device 111. For example, when the terminal device 111 is not performing communication by DC or CA using the second carrier wave, the control unit 303 controls the terminal device 111 to start communication by DC or CA using the second carrier wave based on the difference value between the first received power and the second received power not exceeding a predetermined value. Further, for example, when the terminal device 111 is performing communication by DC or CA using the second carrier wave and the difference value between the first received power and the second received power exceeds a predetermined value, the control unit 303 controls the terminal device 111 to end the communication by DC or CA. Further, for example, when the terminal device 111 is not performing communication by DC or CA using at least either the second carrier wave or the third carrier wave, the difference value between the first received power and the second received power does not exceed a predetermined value, and the difference value between the first received power and the third received power does not exceed a predetermined value, the control unit 303 can determine the carrier wave to be used in communication by DC or CA based on the load of the base station device providing communication by the second carrier wave and the load of the base station device providing communication by the third carrier wave. Note that the control unit 303 can control the terminal device 111, for example, by transmitting a radio resource control (RRC) message to the terminal device 111.

[0026] The setting unit 304 sets the above-described predetermined value for the terminal device 111, for example. For example, when the terminal device 111 executes processing of a plurality of carriers using one communication circuit, the setting unit 304 sets a first predetermined value, and when the terminal device 111 executes processing for a plurality of carriers using a plurality of separate communication circuits for each carrier, it may set a second predetermined value that is larger than the first predetermined value. Note that the setting unit 304 may set a predetermined value based on, for example, the capability information of the terminal device 111 other than the number of communication circuits. That is, even when the difference in received power of a plurality of carriers of the terminal device 111 is large, if the terminal device 111 has the ability to separate signals with high accuracy, the predetermined value may be set to a large value. In this way, the setting unit 304 may set a predetermined value separately for each terminal device based on the capability information of the terminal device. The condition notification unit 305 notifies the terminal device 111 of information indicating conditions to be satisfied when the terminal device 111 reports information regarding the first reception quality and the second reception quality (and optionally the third reception quality) to the base station device 101. Note that the conditions may include, for example, that the difference value between the first received power and the second received power exceeds a predetermined value. Also, the conditions may include, for example, that the difference value between the first received power and the second received power does not exceed a predetermined value. Note that the predetermined value here may be the same value as the predetermined value used in the determination unit 302 or may be a different value.

[0027] (Flow of processing) Next, an example of the processing flow executed by the base station apparatus 101 will be described. First, the base station apparatus 101 sets measurements and reports for the terminal apparatus 111 (S401). For example, the base station apparatus 101 notifies the terminal apparatus 111 of measurement setting information for carriers to be measured (for example, a first carrier corresponding to the serving cell of the terminal apparatus 111 provided by the base station apparatus 101, and a second carrier corresponding to a secondary cell or a candidate for a secondary cell). Further, the base station apparatus 101 instructs the terminal apparatus 111 to notify information related to the first received power of the first carrier and the second received power of the second carrier. Further, the base station apparatus 101 may notify the terminal apparatus 111 of information indicating conditions for reporting, for example.

[0028] Thereafter, the base station apparatus 101 acquires information related to the first received power and the second received power from the terminal apparatus 111 (S402). Then, the base station apparatus 101 specifies a difference value between the first received power and the second received power (S403). For example, in S402, the base station apparatus 101 can acquire information indicating the first received power and information indicating the second received power, and calculate a difference value from the values indicated by those pieces of information in S403. Further, the base station apparatus 101 may receive a message including information indicating a difference value between the first received power and the second received power in S402, and specify the difference value by analyzing the message in S403. Further, the base station apparatus 101 may acquire information capable of specifying whether or not the difference value between the first received power and the second received power exceeds a predetermined value in S402. In this case, it may not be necessary to specify the difference value in S403.

[0029] Here, when the terminal device 111 is communicating in DC or CA (YES in S404), the base station device 101 determines whether the difference value obtained in S403 exceeds a predetermined value (S405). Then, when the difference value exceeds the predetermined value (YES in S405), the base station device 101 decides to terminate the ongoing DC or CA communication and controls the terminal device 111 according to the decision (S406). On the other hand, when the difference value does not exceed the predetermined value (NO in S405), the base station device 101 ends the process without terminating the ongoing DC or CA communication. Even in this case, for example, when there is no longer a need for the terminal device 111 to perform DC or CA communication, the DC or CA communication may naturally end.

[0030] Even when the terminal device 111 is not communicating in DC or CA (NO in S404), the base station device 101 determines whether the difference value obtained in S403 exceeds a predetermined value (S407). Then, when the difference value does not exceed the predetermined value (YES in S407), the base station device 101 permits the terminal device 111 to perform communication by DC or CA (S408). Note that the predetermined value in S407 may be a different value from the predetermined value in S405 or the same value. Then, when the terminal device 111 should perform communication by DC or CA, the base station device 101 executes settings for performing communication by DC or CA. For example, the base station device 101 can control the terminal device 111 by transmitting an RRC message to the terminal device 111. On the other hand, when the difference value does not exceed the predetermined value (YES in S407), the base station device 101 does not permit the terminal device 111 to perform communication by DC or CA and ends the process as it is.

[0031] In this way, in the present embodiment, it is possible to prevent communication by DC or CA using a combination of carriers such that the difference value of the received power of a plurality of carriers measured in the terminal device becomes large. As a result, it becomes possible to improve the communication efficiency, and thus it becomes possible to contribute to Goal 9 of the Sustainable Development Goals (SDGs) led by the United Nations, "Build resilient infrastructure, promote sustainable industrialization and foster innovation."

[0032] The invention is not limited to the above-described embodiments, and various modifications and changes are possible within the scope of the gist of the invention.

Claims

1. A terminal device, A control means for executing control related to dual connectivity or carrier aggregation; A providing means for providing, to a base station device, first information for identifying a communication circuit of the terminal device, and second information regarding a first reception power of the first carrier and a second reception power of the second carrier for the first carrier and the second carrier used in the dual connectivity or the carrier aggregation; A terminal device comprising:

2. 2. The terminal device according to claim 1, wherein the first information is information used to determine whether processing for a plurality of carriers is performed using a single communication circuit or separate communication circuits.

3. The terminal device according to claim 1, characterized in that the first information is information used to determine whether processing of multiple carriers using respective communication circuits for each carrier is possible when a power difference between two carriers that constitute the dual connectivity or the carrier aggregation exceeds a predetermined level.

4. The terminal device according to claim 1, characterized in that the first information is information indicating whether or not the terminal device has a communication circuit for preventing a decrease in throughput and obtaining a predetermined throughput when a power difference between two carriers that constitute the dual connectivity or the carrier aggregation exceeds a predetermined level.

5. The terminal device according to claim 11, characterized in that the terminal device is connected to a base station device that instructs the terminal device to start or end the dual connectivity or the carrier aggregation based on a result of a determination made when the determination is made based on the first information and a received power difference between the first received power and the second received power acquired from the terminal device, and that instructs the terminal device to start or end the dual connectivity or the carrier aggregation based on the result of the determination.

6. A control method executed by a terminal device that executes control related to dual connectivity or carrier aggregation, A control method comprising: providing, to a base station device, first information for identifying a communication circuit of the terminal device, and second information regarding a first received power of the first carrier and a second received power of the second carrier for a first carrier and a second carrier used for the dual connectivity or the carrier aggregation.

7. A computer provided in a terminal device that executes control related to dual connectivity or carrier aggregation, A program for causing a base station device to provide first information for identifying a communication circuit of the terminal device and second information regarding a first received power of the first carrier and a second received power of the second carrier for a first carrier and a second carrier used for the dual connectivity or the carrier aggregation.

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