JP2015056780A - Base station apparatus, communication apparatus, control method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To deliver maximum power transmission for a plurality of base stations at a terminal, by taking account of transmission power usable by the terminal when the terminal is simultaneously connected to a plurality of base stations.SOLUTION: A base station apparatus, in a radio communication system in which a communication system can be simultaneously connected with one or more other base station apparatuses, determines first maximum transmission power usable when the communication device transmits a signal to the base station apparatus and second maximum transmission power usable when the communication device transmits a signal to each of the other base station apparatuses so that the sum of the first maximum transmission power and second maximum transmission power does not exceed third maximum transmission power usable in the communication device. The communication device is informed of the first maximum transmission power as well as the one or more other base station apparatuses are informed of the second maximum power transmission. The communication device is informed of the second maximum transmission power by one of the one or more other base station apparatuses.

Description

  The present invention relates to a transmission power control technique for a terminal in a wireless communication system.

  In the 3rd Generation Partnership Project (3GPP), installing many small cells (small cells) that use different frequency bands (for example, higher frequency bands than those used in macro cells) within the coverage of large cells (macro cells) Has been discussed. For example, as in the example of FIG. 1, a plurality of small cells using the 3.5 GHz band frequency band are placed in the coverage area of the macro cell using the 2 GHz band frequency band.

  In LTE Release 12, discussions have begun on a technique called Dual Connectivity in which two types of base stations cooperate in a layer higher than the MAC (medium access control) layer in such an environment (see Non-Patent Document 1). Here, the two types of base stations are a master eNB (for example, a macro base station) and a slave eNB (for example, a small cell base station), where the master eNB leads communication control, and the slave eNB controls communication control. Operates based on. In Dual Connectivity, it is assumed that two types of base stations are connected by a wired or wireless backhaul line, and for example, traffic transmitted to a terminal is passed to a slave eNB via a master eNB. . The passed signal is then transmitted as a radio signal from the slave eNB to the terminal. Moreover, the signal transmitted from the terminal to the slave eNB is transferred from the slave eNB to the master eNB. That is, all or most of the traffic passes through the master eNB once.

  Here, the backhaul line is required to have a large capacity such as 1 Gbps, for example, while the request for the delay is not relatively severe such as 10 msec or more. Therefore, as shown in FIG. 2, in dual connectivity, control data (C-plane) for maintaining mobility and data with high real-time properties such as voice call traffic are transmitted from the master eNB to the terminal. On the other hand, best-effort user data (U-plane) that does not require real-time performance such as Web browsing is transmitted from the slave eNB to the terminal. Thereby, it is possible to perform data offloading to the slave eNB without performing handover associated with connection to the slave eNB.

Samsun, R1-131830, “Discussion on dual RRC”, 3GPP TSG RAN WG2 # 82, May 2013

  In Dual Connectivity, the terminal transmits the transmission power to the master eNB and the slave eNB based on the propagation loss in the communication path to each eNB, the offset value notified from each eNB, the allocated resource amount, and the like. To decide. In addition, since it is assumed that the delay of the backhaul line between eNBs is large, each eNB performs allocation of resources independently. At this time, the master eNB and the slave eNB notify the terminal of the maximum transmission power that can be used by the terminal for communication between the terminal and the eNB. That is, the master eNB notifies the terminal of the first maximum transmission power that can be used when the terminal transmits a signal to the master eNB in communication between the master eNB and the terminal. Similarly, in the communication between the slave eNB and the terminal, the slave eNB notifies the terminal of the second maximum transmission power that can be used when the terminal transmits a signal to the slave eNB. This maximum transmission power is determined by each eNB so that the signal from the terminal has a predetermined radio quality.

  At this time, the master eNB cannot know the second maximum transmission power, and the slave eNB cannot know the first maximum transmission power. And even if the sum of the first maximum transmission power and the second maximum transmission power exceeds the third maximum transmission power that can be used as the terminal's own capability, each eNB can know it. There wasn't. As a result, for example, when a terminal allocates a large amount of power to transmit a signal to one of the eNBs, the power allocated to the signal to another eNB is insufficient, and the reception quality assumed by the eNB cannot be maintained. There was a case.

  The present invention has been made in view of the above problems, and considers the transmission power that can be used by a terminal when the terminal is connected to a plurality of base stations at the same time. The purpose is to allocate.

  In order to achieve the above object, a base station apparatus according to the present invention is the base station apparatus in a wireless communication system in which the communication apparatus can be connected simultaneously with the base station apparatus and one or more other base station apparatuses. A first maximum transmission power that can be used when a device transmits a signal to the base station device, and a first maximum transmission power that can be used when the communication device transmits a signal to each of the one or more other base station devices. Determining means for determining a maximum transmission power of 2 so that a sum of the first maximum transmission power and the second maximum transmission power does not exceed a third maximum transmission power usable in the communication device; Notification means for notifying the first maximum transmission power to the communication device and notifying each of the one or more other base station devices of the second maximum transmission power, and the second Maximum transmission power The by the notification means is notified to the communication device, or is notified from each of the one or more other base station apparatus to the communication device, it is characterized.

  In order to achieve the above object, a communication apparatus according to the present invention is a communication apparatus that can be connected simultaneously with a base station apparatus and one or more other base station apparatuses, from the base station apparatus to the base station apparatus. Information on the first maximum transmission power that can be used for transmission of a signal of the base station apparatus and the one or more other base station apparatuses from each of the base station apparatus or the one or more other base station apparatuses. When acquiring a signal simultaneously to each of the base station apparatus and the one or more other base station apparatuses, acquisition means for acquiring information on the second maximum transmission power that can be used for transmission of the signal to each, Transmitting means for transmitting the signal at a power not exceeding the first maximum transmission power and the second maximum transmission power, respectively, and the first maximum transmission power and the second maximum transmission power The sum of the third It does not exceed the atmospheric transmission power, characterized in that.

  According to the present invention, when a terminal is connected to a plurality of base stations at the same time, it is possible to allocate the maximum transmission power to the plurality of base stations in the terminal in consideration of the transmission power usable by the terminal.

The conceptual diagram which shows the example of arrangement | positioning of the macro cell and small cell which each use a different frequency band. The conceptual diagram which shows the example of communication between the terminal and multiple eNB by Dual Connectivity. The figure which shows the hardware structural example of a master eNB, a slave eNB, and a terminal. The block diagram which shows the function structural example of the master eNB. The block diagram which shows the function structural example of a slave eNB. The block diagram which shows the function structural example of a terminal. The sequence diagram which shows the example of the flow of a process until the maximum transmission power is determined and notified to a terminal.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(System configuration)
The radio communication system according to the present embodiment includes, for example, a master eNB, a slave eNB, and a terminal (UE) as illustrated in FIG. Here, eNB is a base station apparatus, but the corresponding wireless communication system may be other than LTE. The terminal is a mobile unit or a fixed radio communication device, and may correspond to a radio communication system other than LTE. In the wireless communication system of the present embodiment, the master eNB performs communication using a first frequency band (for example, 2 GHz), and the slave eNB performs communication using a second frequency band (3.5 GHz).

  The master eNB and the slave eNB are connected to each other by a wired or wireless communication line (backhaul line). And a downlink signal reaches a terminal by being transmitted to a terminal as a radio signal directly from a master eNB, or being transmitted as a radio signal from a slave eNB to a terminal after being transferred from a master eNB to a slave eNB . Further, the uplink signal arrives at the master eNB when the terminal directly transmits to the master eNB or when the slave eNB transfers a signal transmitted from the terminal to the slave eNB. Note that communication between the terminal and another device directly connected to the slave eNB may not pass through the master eNB.

  Note that FIG. 2 illustrates the case where only one slave eNB exists, but the following discussion can be applied to any case where one or more slave eNBs exist. Further, FIG. 2 shows a case where only one terminal exists, but the following discussion can be applied to any case where one or more terminals exist. .

  Here, conventionally, as described above, the master eNB cannot know the second maximum transmission power set by the slave eNB, and the slave eNB does not know the first maximum transmission power set by the master eNB. I can't know. For this reason, the sum of the first maximum transmission power and the second maximum transmission power (the sum of the second maximum transmission powers set by each slave eNB when there are a plurality of slave eNBs) In some cases, the third maximum transmission power is exceeded. In this case, for example, the terminal first allocates power for signal transmission to the master eNB, and then subtracts the power already allocated from the third maximum transmission power for signal transmission to the slave eNB. Allocate power. At this time, if the terminal allocates a lot of power to the signal transmission to the master eNB, the power allocated to the signal transmission to the slave eNB becomes insufficient and the radio quality in the slave eNB deteriorates. was there. That is, when the sum of the maximum transmission power for each eNB exceeds the maximum transmission power due to the capability of the terminal, the distribution of the transmission power for the signal to each eNB in the terminal is biased. In some cases, the quality deteriorated.

  For this reason, in this embodiment, the master eNB determines both the first maximum transmission power and the second maximum transmission power so as not to exceed the third maximum transmission power. That is, the master eNB also determines the second maximum transmission power for the slave eNB in addition to the first maximum transmission power for the master eNB itself so that transmission power distribution in the terminal is not biased. Thereby, for example, the terminal does not allocate excessive power to the signal to the master eNB, and the probability that the radio quality of the signal from the terminal satisfies the predetermined quality in the slave eNB can be increased.

  Then, the structure and operation | movement of eNB and a terminal are demonstrated in detail.

(ENB and terminal hardware configuration)
FIG. 3 is a diagram illustrating a hardware configuration example of a master eNB, a slave eNB (base station device), and a terminal (mobile / fixed communication device). For example, the master eNB, the slave eNB, and the terminal have the same hardware configuration as illustrated in FIG. 3, and include, for example, a CPU 301, a ROM 302, a RAM 303, an external storage device 304, and a communication device 305. In the master eNB, the slave eNB, and the terminal, for example, a program that realizes each function of the master eNB, the slave eNB, and the terminal, which is recorded in any of the ROM 302, the RAM 303, and the external storage device 304, is executed by the CPU 301. The Then, the master eNB, the slave eNB, and the terminal, for example, control the communication device 305 by the CPU 301, and perform communication between the master eNB or slave eNB and the terminal, or communication between eNBs between the master eNB and the slave eNB. Do.

  In FIG. 3, the master eNB, the slave eNB, and the terminal have one communication device 305. For example, the eNB has a communication device for communication between eNBs and a communication device between the terminals. May be. Moreover, the terminal may have a plurality of communication devices corresponding to each of a plurality of frequency bands, for example.

  Note that the master eNB, the slave eNB, and the terminal may be provided with dedicated hardware that executes each function described below, or a computer that executes part of the hardware and operates the program. May be executed. Further, all the following functions may be executed by a computer and a program.

(Functional configuration of master eNB)
FIG. 4 is a block diagram illustrating a functional configuration example of the master eNB. The master eNB includes, for example, a maximum transmission power determination unit 401, a wireless communication unit 402, a wired communication unit 403, and an information reception unit 404. Note that the master eNB can further include other functional units included in the normal eNB, but in the present embodiment, description of such functional units is omitted for the sake of simplicity.

  The wireless communication unit 402 is a functional unit that performs wireless communication with a terminal. The wired communication unit 403 is a functional unit that performs wired communication with the slave eNB via, for example, the X2 interface. The wireless communication unit 402 and the wired communication unit 403 notify the terminal of the first maximum transmission power determined by the maximum transmission power determination unit 401 described later, and notify the terminal or slave eNB of the second maximum transmission power. In addition, when the second maximum transmission power is notified to the slave eNB, the slave eNB stores information on the second maximum transmission power and transfers the information to the terminal. Further, the notification of the first maximum transmission power (and the notification of the second maximum transmission power by radio) is broadcast toward all terminals in the cell by a broadcast signal, for example. Note that communication between the master eNB and the slave eNB may be performed by wireless communication using the wireless communication unit 402.

  The maximum transmission power determination unit 401 determines a first maximum transmission power and a second maximum transmission power that can be used when the terminal transmits an uplink signal to the master eNB and the slave eNB. Note that the maximum transmission power determination unit 401 starts the determination processing of the first maximum transmission power and the second maximum transmission power when receiving a request for determining the maximum transmission power from the slave eNB. Good.

  For example, the maximum transmission power determination unit 401 determines the first maximum transmission power and the second maximum transmission power according to the total number of master eNBs and slave eNBs. For example, when the terminal is connected to one master eNB and one slave eNB at the same time, the maximum transmission power determination unit 401 uses the first maximum transmission power as a result of dividing the third maximum transmission power by 2. And the second maximum transmission power. Similarly, when a terminal is simultaneously connected to one master eNB and N slave eNBs, the maximum transmission power determination unit 401 adds the third maximum transmission power to N + 1 (ie, adds 1 to the number of slave eNBs). Value). Then, the maximum transmission power determination unit 401 determines the division result as the first maximum transmission power for the master eNB and the second maximum transmission power for each of the N slave eNBs. In this case, the first maximum transmission power + N × the second maximum transmission power = the third maximum transmission power.

  In addition, the maximum transmission power determination unit 401 calculates the second maximum transmission power by dividing the third maximum transmission power by a value obtained by adding a value larger than 1 to the number of slave eNBs, and calculates the second maximum transmission power from the calculation result. The maximum transmission power of 1 may be calculated. For example, when the terminal is connected to one master eNB and M slave eNBs, the maximum transmission power determination unit 401 divides the third maximum transmission power by M + 2 to A second maximum transmission power is determined. Then, the maximum transmission power determination unit 401 calculates the sum of the second maximum transmission powers (that is, the second maximum transmission power × M), and subtracts the result from the third maximum transmission power, thereby The maximum transmission power of 1 is calculated. For example, when M = 2, the second maximum transmission power is a value obtained by dividing the third maximum transmission power by 2 + 2 = 4, that is, 1/4 of the third maximum transmission power. The first maximum transmission power is a value obtained by subtracting the total of the second maximum transmission powers (second maximum transmission power × M (= 2)) from the third maximum transmission power, that is, 3 of the maximum transmission power of 3. Similarly, when M = 1, the first maximum transmission power is 2/3 of the third maximum transmission power, and the second maximum transmission power is 1/3 of the third maximum transmission power. Note that the slave eNBs need not all have the same second maximum transmission power. For example, the sum of the second maximum transmission power may be calculated by the above calculation, and the maximum transmission power may be allocated to each slave eNB within a range not exceeding the result. In these calculations, the maximum transmission power determination unit 401 can easily calculate the first maximum transmission power and the second maximum transmission power only by knowing the number of slave eNBs to which the terminal can be connected simultaneously. Become.

  Further, the maximum transmission power determination unit 401 may determine, as the first maximum transmission power, the transmission power required for the uplink predetermined signal from the terminal to be received at the master eNB with the predetermined quality. . The predetermined signal is, for example, a PUCCH (physical uplink control channel). In this case, the second maximum transmission power is given, for example, as a result of dividing the result of subtracting the first maximum transmission power from the third maximum transmission power by the number of slave eNBs. The second maximum transmission power may be calculated so that the result of subtracting the first maximum transmission power from the third maximum transmission power is equal to or greater than the sum of the second maximum transmission powers. The same second maximum transmission power need not be determined for the slave eNB. Thus, for example, with respect to the control channel or the like, it is possible to secure power that can be received by the eNB and perform power distribution so that data communication is performed using the remaining power.

  In addition, when a plurality of terminals are connected to the master eNB, the maximum transmission power determination unit 401 acquires the value of the signal transmission power required for the master eNB to receive with a predetermined quality for each of the plurality of terminals, The maximum value of the acquired values may be determined as the first maximum transmission power. That is, the first maximum transmission power may be determined such that signals from all terminals connected to the master eNB are received with a predetermined quality at the master eNB.

  Further, the maximum transmission power determining unit 401 determines the first maximum transmission power and the second based on the magnitude of the propagation loss between the master eNB and the terminal and the magnitude of the propagation loss between the slave eNB and the terminal. May be determined. For example, the maximum transmission power determination unit 401 may determine the first maximum transmission power and the second maximum transmission power so that the maximum transmission power is proportional to the ratio of the magnitude of propagation loss. Specifically, when the magnitude of the propagation loss between the master eNB and the terminal is twice the magnitude of the propagation loss between the slave eNB and the terminal, the first maximum transmission power is It may be determined to be twice the maximum transmission power of 2. Note that the magnitude of the propagation loss between the slave eNB and the terminal may be received by the information receiving unit 404 from the terminal via the wireless communication unit 402 or from the slave eNB via the wired communication unit 403. Also good. In addition, when there are a plurality of terminals connected to the master eNB and the slave eNB, the above-described propagation loss magnitude is the maximum value of the propagation loss magnitude between each of the plurality of terminals and the eNB. May be. Furthermore, the master eNB may request information on propagation loss between the slave eNB and the terminal from the terminal or the slave eNB by an information request unit (not shown). Thereby, it becomes possible to ensure a certain communication quality for all terminals connected to the eNB. Thereby, in consideration of the propagation loss, the maximum transmission power can be allocated so that the radio quality of the signal from the terminal in each eNB is not biased.

  In addition, the maximum transmission power determination unit 401 uses the first maximum transmission power and the second maximum transmission power based on parameters for determining transmission power used when the terminal transmits signals to the master eNB and the slave eNB. May be determined. In addition, the parameter regarding the slave eNB may be received by the information reception unit 404 from the terminal via the wireless communication unit 402, or may be received from the slave eNB via the wired communication unit 403. Furthermore, the master eNB may request information on propagation loss between the slave eNB and the terminal from the terminal or the slave eNB by an information request unit (not shown).

  Here, the parameter may include an offset value, and the offset value is a value that determines transmission power used by the terminal by being added to the propagation loss. For example, the maximum transmission power determination unit 401 sets the first maximum transmission power and the second maximum so that the ratio of the sum of the propagation loss and the offset value in the master eNB and the slave eNB becomes a ratio with the maximum transmission power. The transmission power may be determined. Further, the parameter may be a path loss correction coefficient for correcting the value of propagation loss when determining transmission power. The maximum transmission power determination unit 401, for example, the first maximum transmission power and the ratio of the value obtained by multiplying the propagation loss in the master eNB and the slave eNB by the respective path loss correction coefficients become the ratio of the maximum transmission power. The second maximum transmission power may be determined. Further, the parameter may include an average value of the number of radio resources allocated to individual terminals by the master eNB and the slave eNB during a predetermined period of time from the past to the present, for example. In this case, for example, the first transmission rate is set so that a ratio of values obtained by performing logarithmic calculation on the average value of the allocated resources and adding the propagation loss in the master eNB and the slave eNB is the ratio of the maximum transmission power. The maximum transmission power and the second maximum transmission power may be determined.

を満たすように、第１の最大送信電力（Ｐ_M ^MAX）および第２の最大送信電力（Ｐ_S ^MAX）が決定されてもよい。ここで、ＰＬ_M ^MAXおよびＰＬ_S ^MAXは、それぞれマスタｅＮＢとスレーブｅＮＢとにおける、端末との間の伝搬損失の最大値である。また、α_Mおよびα_Sは、それぞれマスタｅＮＢとスレーブｅＮＢとにおけるパスロス補正係数である。また、Ｎ_MおよびＮ_Sは、それぞれマスタｅＮＢとスレーブｅＮＢとにおいて、１つの端末に対して割り当てられた（１つのＵＥが占有した）無線リソースの数の平均値である。そして、Ｏ_MおよびＯ_Sは、それぞれマスタｅＮＢおよびスレーブｅＮＢにおいて設定されたオフセット値である。これらのようにすることで、その時点における送信電力の設定を考慮して、適切な配分の最大送信電力を決定することが可能となる。 Put them all together, for example,

The first maximum transmission power (P _M ^MAX ) and the second maximum transmission power (P _S ^MAX ) may be determined so as to satisfy Here, PL _M ^MAX and PL _S ^MAX are the maximum values of the propagation loss between the master eNB and the slave eNB, respectively. Α _M and α _S are path loss correction coefficients in the master eNB and the slave eNB, respectively. N _M and N _S are average values of the number of radio resources allocated to one terminal (occupied by one UE) in each of the master eNB and the slave eNB. O _M and O _S are offset values set in the master eNB and the slave eNB, respectively. By doing so, it is possible to determine the maximum transmission power of an appropriate distribution in consideration of the transmission power setting at that time.

  Note that the first maximum transmission power and the second maximum transmission power may have a minimum value and a maximum value, respectively. For example, when the first maximum transmission power calculated as described above is smaller than the minimum value of the first maximum transmission power, the maximum transmission power determination unit 401 sets the first maximum transmission power to the minimum value. change. Similarly, for example, when the calculated first maximum transmission power is larger than the maximum value of the first maximum transmission power, the maximum transmission power determination unit 401 changes the first maximum transmission power to the maximum value. . Regarding the second maximum transmission power, the calculated value may be changed to the minimum value when it is smaller than the minimum value that can be set, and the maximum value when the calculated value is larger than the maximum value that can be set.

  And the maximum transmission power determination part 401 may readjust the value of the maximum transmission power other than the changed maximum transmission power according to the change. That is, for example, when the first maximum transmission power is changed, the maximum transmission power determination unit 401 determines that the value obtained by subtracting the changed value from the third maximum transmission power is equal to or greater than the sum of the second maximum transmission powers. The second maximum transmission power is readjusted so that Similarly, for example, when the second maximum transmission power is changed, the maximum transmission power determination unit 401 obtains a value obtained by subtracting the sum of the second maximum transmission power after the change from the third maximum transmission power. The first maximum transmission power is readjusted so that the maximum transmission power is 1 or more. Thereby, it is possible to control the power of the signal to be appropriately distributed to each eNB while preventing the first maximum transmission power and the second maximum transmission power from being allocated too little or excessively.

  The information reception unit 404 receives information for determining the maximum transmission power from the terminal via the wireless communication unit 402 or from the slave eNB via the wired communication unit 403.

  In addition, when there are a plurality of types of the third maximum transmission power depending on the terminal capability, the master eNB sets the first maximum transmission power and the second maximum transmission power for each third maximum transmission power. You may decide. In this case, the master eNB includes information on the first maximum transmission power and the second maximum transmission power that may be different for each third maximum transmission power in the broadcast signal, and broadcasts the broadcast signal. When the terminal receives the broadcast signal, the terminal extracts the first maximum transmission power and the second maximum transmission power corresponding to the third maximum transmission power in the terminal's own capability, and the maximum transmission power for each eNB is extracted. Set. When the third maximum transmission power is determined for each category of the terminal, information indicating the first maximum transmission power and the second maximum transmission power associated with the category is included in the broadcast signal, and the terminal May be notified. In that case, the terminal extracts the first maximum transmission power and the second maximum transmission power corresponding to the category to which the terminal belongs from the broadcast signal, and sets the maximum transmission power for each eNB. Thereby, even if the maximum transmission power may be different for each terminal, the master eNB determines and notifies the first maximum transmission power and the second maximum transmission power according to each maximum transmission power Is possible.

(Configuration of slave eNB)
FIG. 5 is a block diagram illustrating a functional configuration example of the slave eNB. The slave eNB includes, for example, an information acquisition unit 501, a maximum transmission power setting unit 502, an information notification unit 503, a wireless communication unit 504, and a wired communication unit 505. Note that the slave eNB can further include other functional units included in the normal eNB, but in the present embodiment, description of such functional units is omitted for the sake of simplicity. For example, the information acquisition unit 501 acquires information on the second maximum transmission power from the master eNB via the wired communication unit 505. Then, the maximum transmission power setting unit 502 sets the second maximum transmission power as the maximum transmission power of the terminal for the slave eNB.

  For example, the information notification unit 503 notifies the terminal of the second maximum transmission power via the wireless communication unit 504 using a notification signal. When the master eNB notifies the terminal of the second maximum transmission power information by wireless communication, there is no need for a notification signal for notifying the second maximum transmission power. Further, the information notification unit 503 notifies the master eNB of, for example, information on propagation loss between the terminal and the slave eNB and information on parameters for setting transmission power via the wired communication unit 505. Note that the propagation loss information and the like may be acquired from the wireless quality measurement report by the terminal via the wireless communication unit 504. Further, for example, when the master eNB determines the maximum transmission power only by the number of slave eNBs, or when the master eNB acquires information from the terminal, there is no need to notify these information. Note that the information notification unit 503 sends a request for setting the maximum transmission power via the wired communication unit 505 when the setting of the maximum transmission power is necessary, when the terminal enters the dual connectivity state, or periodically. You may transmit to eNB.

  The wireless communication unit 504 is a functional unit for performing wireless communication with a terminal, and the wired communication unit 505 is a functional unit for performing wired communication with a master eNB (or another slave eNB). is there. The wired communication unit 505 performs communication between eNBs using, for example, an X2 interface. Note that communication between the master eNB and the slave eNB may be performed by wireless communication using the wireless communication unit 504.

(Terminal configuration)
FIG. 6 is a block diagram illustrating a functional configuration example of the terminal. The terminal includes, for example, an information acquisition unit 601, a maximum transmission power storage unit 602, a transmission power setting unit 603, an information providing unit 604, and a wireless communication unit 605. In addition, although a terminal can further have another function part with which a normal terminal is provided, in this embodiment, in order to simplify description, description is abbreviate | omitted about such a function part. The radio communication unit 605 is a functional unit that performs radio communication with each eNB, and transmits a radio signal to each eNB using the transmission power set by the transmission power setting unit 603.

  For example, the information acquisition unit 601 acquires the first maximum transmission power and the second maximum transmission power from the master eNB via the wireless communication unit 605. Note that the second maximum transmission power may be acquired from the slave eNB. The acquired information about the first maximum transmission power and the second maximum transmission power is stored in the maximum transmission power storage unit 602.

  When the transmission power setting unit 603 transmits signals to the master eNB and the slave eNB at the same time, the transmission power for the master eNB is equal to or lower than the first maximum transmission power, and the transmission power for the slave eNB is equal to or lower than the second maximum transmission power. And set the transmission power respectively. The set transmission power is notified to the radio communication unit 605, and the amplification amount of the signal transmitted to each eNB is controlled based on the set transmission power.

  The transmission power setting unit 603 may always monitor whether a signal is simultaneously transmitted to the master eNB and the slave eNB. For example, when transmitting a signal only to the master eNB, the first maximum transmission is performed. The transmission power may be set exceeding the power. However, in this case, the transmission power is set so as not to exceed the third maximum transmission power. In addition, when there are a plurality of slave eNBs and a signal is transmitted only to some of the slave eNBs, the transmission power setting unit 603 determines the maximum transmission power for the slave eNBs that are not the target of signal transmission, You may allocate to the maximum transmission power about eNB. For example, when there are two slave eNBs, as an example, the first maximum transmission power and the second maximum transmission power are both determined as 1/3 of the third maximum transmission power. On the other hand, when a signal is transmitted to only one of the two slave eNBs, the transmission power setting unit 603 allocates the maximum transmission power for the slave eNB that is not a signal transmission target. In this case, for example, the transmission power setting unit 603 can set the transmission power for the master eNB and one slave eNB within a range that is ½ or less of the third maximum transmission power.

  The information providing unit 604 forms, as a message, information for determining the maximum transmission power, such as a result of measuring radio quality such as a propagation loss between each eNB, and the message is transmitted through the radio communication unit 605. Notify master eNB or slave eNB. Moreover, the information provision part 604 may notify the master eNB of the number of eNBs which can be connected simultaneously. In this case, for example, the master eNB can determine the maximum transmission power for each eNB according to the notified maximum value of the number of eNBs.

  Thus, by allocating the maximum transmission power for each eNB to the terminal, it becomes possible to prevent an event such as biasing only to signals for the eNB having the transmission power. Further, if the terminal does not simultaneously transmit signals to at least some of the plurality of eNBs, the maximum transmission power is allocated to signals to other eNBs, thereby improving communication reliability. Is possible.

(Processing flow from determination of maximum transmission power to notification)
Subsequently, a flow until the first maximum transmission power and the second maximum transmission power are determined and then the determined maximum transmission power is notified to the terminal will be described. 7A to 7D show examples of the flow of these processes.

  In the example of FIG. 7A, first, the master eNB uniquely determines the first maximum transmission power and the second maximum transmission power. At this time, the master eNB may execute the determination of the first maximum transmission power and the second maximum transmission power, for example, every predetermined period. For example, when a terminal that is in Dual Connectivity occurs This determination may be performed. Thereafter, the master eNB notifies the terminal of the determined second maximum transmission power. Then, the master eNB notifies the terminal of the determined first maximum transmission power using the notification signal. At this time, the same first maximum transmission power is notified to a plurality of terminals in the cell where the master eNB is deployed. On the other hand, the slave eNB similarly notifies the terminal of the notified second maximum transmission power using the broadcast signal. As a result, the slave eNB can grasp the second maximum transmission power determined by the master eNB, and can notify both the first maximum transmission power and the second maximum transmission power to the terminal. It becomes possible.

  In the example of FIG. 7B, first, the slave eNB notifies the master eNB of a request for determining the maximum transmission power. At this time, the slave eNB may notify the master eNB of information used to determine the maximum transmission power, such as various parameters. Thereafter, the master eNB determines the first maximum transmission power and the second maximum transmission power according to the request, and the determined maximum transmission power is determined for the slave eNB and the terminal as in FIG. Notify information. In addition, when the parameter from the slave eNB is not used in determining the maximum transmission power, the master eNB transmits the maximum transmission in response to receiving the request for determining the maximum transmission power from the terminal, not from the slave eNB. The power determination process may be started. Accordingly, it is possible to prompt the master eNB to determine the maximum transmission power in response to sensing that an event that should determine the maximum transmission power has occurred in the slave eNB (or terminal). Also, the slave eNB notifies the master eNB of parameters for determining the maximum transmission power, so that the master eNB allocates the maximum transmission power in each eNB on the premise of conditions such as the transmission power setting at that time. It becomes possible.

  In the example of FIG. 7C, first, the master eNB determines that the maximum transmission power determination process is executed, and information used to determine the maximum transmission power, such as various parameters, for the slave eNB. Request. Then, the master eNB receives parameters from the slave eNB and uses the parameters to determine the first maximum transmission power and the second maximum transmission power. Processing after parameter reception is the same as that in FIG. As a result, it is possible to detect that an event for determining the maximum transmission power has occurred in the master eNB and start the determination process of the maximum transmission power.

  In the example of FIG. 7D, first, the master eNB determines the first maximum transmission power and the second maximum transmission power as in any of FIGS. 7A to 7C. Then, after notifying the slave eNB of the second maximum transmission power, the master eNB notifies the terminal not only of the first maximum transmission power but also of the second maximum transmission power. Thereby, the maximum transmission power is not notified individually from the master eNB and the slave eNB, but the maximum transmission power is notified collectively from the master eNB. For this reason, for example, it becomes possible to reduce the amount of signaling.

  Thus, in the master eNB, it becomes possible to set the maximum transmission power that can be used when the terminal transmits to each eNB so that the sum does not exceed the maximum transmission power in the terminal capability. . Therefore, it is possible to prevent the transmission power of the signal at the terminal from being unevenly distributed, and for example, it is possible to maintain the reception quality of the signal at each eNB at a predetermined quality or higher.

Claims (25)

The base station apparatus in a wireless communication system in which the communication apparatus can be connected simultaneously with the base station apparatus and one or more other base station apparatuses,
A first maximum transmission power that can be used when the communication device transmits a signal to the base station device, and a communication device that is used when the communication device transmits a signal to each of the one or more other base station devices. Determining means for determining a second maximum transmission power that can be generated so that a sum of the first maximum transmission power and the second maximum transmission power does not exceed a third maximum transmission power that can be used in the communication device; ,
Notifying means for notifying the first maximum transmission power to the communication device, and notifying the second maximum transmission power to each of the one or more other base station devices;
Have
The second maximum transmission power is notified to the communication apparatus by the notification means, or is notified to the communication apparatus from each of the one or more other base station apparatuses.
A base station apparatus. The determining means determines the first maximum transmission power and the second maximum transmission power according to the number of the one or more other base station devices.
The base station apparatus according to claim 1. The determination means divides the third maximum transmission power by a number obtained by adding 1 to the number of the one or more other base station apparatuses, and determines the first maximum transmission power and the second maximum transmission power. Determine as transmission power,
The base station apparatus according to claim 2. The determining means determines the result of dividing the third maximum transmission power by the number obtained by adding a number greater than 1 to the number of the one or more other base station apparatuses as the second maximum transmission power, A result obtained by subtracting the determined sum of the second maximum transmission powers from the third maximum transmission power is determined as the first maximum transmission power;
The base station apparatus according to claim 2. The determining means determines, as the first maximum transmission power, a transmission power in the communication apparatus required for a signal transmitted by the communication apparatus to be received at a predetermined quality in the base station apparatus. The second maximum transmission power so that the result of subtracting the maximum transmission power of 1 from the third maximum transmission power is equal to or greater than the sum of the second maximum transmission powers in each of the one or more other base station apparatuses. Determine the maximum transmit power of the
The base station apparatus according to claim 1. When the base station apparatus is connected to a plurality of communication apparatuses, the determining means transmits transmission power required for signals transmitted from the plurality of communication apparatuses to be received at the base station apparatus with the predetermined quality. A maximum transmission power value is determined as the first maximum transmission power.
The base station apparatus according to claim 5. The determining means includes a first propagation loss between the base station device and the communication device, and a second propagation loss between each of the one or more other base station devices and the communication device. Determining the first maximum transmission power and the second maximum transmission power based on
The base station apparatus according to claim 1. When the base station device is connected to a plurality of communication devices, the determining means determines the maximum propagation loss among the propagation losses between the base station device and each of the plurality of communication devices. Propagation between each of the one or more other base station apparatuses and each of the plurality of communication apparatuses when the one or more other base station apparatuses are connected to a plurality of communication apparatuses. Determining the first maximum transmission power and the second maximum transmission power with the largest of the losses as the second propagation loss;
The base station apparatus according to claim 7. The determining means receives the information on the second propagation loss from the one or more other base station devices, and determines the first maximum transmission power and the second maximum transmission power.
The base station apparatus according to claim 7 or 8, wherein Requesting means for requesting the one or more other base station apparatuses for information on the second propagation loss;
The base station apparatus according to claim 9. The determining means includes a first parameter for determining transmission power used when the communication apparatus transmits a signal to the base station apparatus, and each of the one or more other base station apparatuses is used by the communication apparatus. Further determining the first maximum transmission power and the second maximum transmission power based further on a second parameter for determining a transmission power to be used when transmitting a signal to
The base station apparatus according to claim 7 or 8, wherein The determining means receives the information of the second parameter from the one or more other base station devices, and determines the first maximum transmission power and the second maximum transmission power.
The base station apparatus according to claim 11. Requesting means for requesting the one or more other base station apparatuses for information on the second parameter;
The base station apparatus according to claim 12. The first parameter includes an average value of the number of radio resources used by one of the communication devices connected to the base station device, and the second parameter is connected to the other base station device. Including an average value of the number of radio resources used by one of the communication devices;
The base station apparatus according to claim 11, wherein the base station apparatus is a base station apparatus. The first parameter includes an offset value that determines a transmission power of a signal to be transmitted to the base station device of the communication device by being added to the first propagation loss, and the second parameter is the second parameter Including an offset value that determines the transmission power of the signal transmitted to the other base station device of the communication device by being added to the propagation loss of
The base station apparatus according to any one of claims 11 to 14, wherein the base station apparatus is characterized in that The first parameter includes a coefficient for correcting the first propagation loss when determining transmission power of a signal transmitted from the communication apparatus to the base station apparatus, and the second parameter is the communication parameter. A coefficient for correcting the second propagation loss when determining transmission power of a signal to be transmitted to the other base station device of the device;
The base station apparatus according to claim 11, wherein the base station apparatus is a base station apparatus. The determining means determines the first maximum transmission power and the second maximum transmission power in response to receiving a request for determining the maximum transmission power from the other base station device.
The base station apparatus according to any one of claims 1 to 16, wherein: The determination means further changes or determines the first maximum transmission power to the minimum value when the determined first maximum transmission power is smaller than the minimum value of the first maximum transmission power. When the first maximum transmission power is larger than the maximum value of the first maximum transmission power, the first maximum transmission power is changed to the maximum value, and the changed first maximum transmission power is changed to the first value. Changing the second maximum transmission power so that a value subtracted from the maximum transmission power of 3 is equal to or greater than the sum of the second maximum transmission powers;
The base station apparatus according to claim 1, wherein the base station apparatus is a base station apparatus. The determination means further changes or determines the second maximum transmission power to the minimum value when the determined second maximum transmission power is smaller than the minimum value of the second maximum transmission power. When the second maximum transmission power is larger than the maximum value of the second maximum transmission power, the second maximum transmission power is changed to the maximum value, and the sum of the second maximum transmission power after the change is Changing the first maximum transmission power such that a value subtracted from the third maximum transmission power is equal to or greater than the first maximum transmission power;
The base station apparatus according to claim 1, wherein the base station apparatus is a base station apparatus. A communication device that can be connected simultaneously with a base station device and one or more other base station devices,
From the base station apparatus to obtain information of the first maximum transmission power that can be used for signal transmission to the base station apparatus, and from each of the base station apparatus or the one or more other base station apparatus, Obtaining means for obtaining information of a second maximum transmission power that can be used for transmitting a signal to each of the one or more other base station devices;
When transmitting a signal to each of the base station apparatus and the one or more other base station apparatuses at the same time, the signal with power not exceeding the first maximum transmission power and the second maximum transmission power, respectively. Transmitting means for transmitting
Have
The sum of the first maximum transmission power and the second maximum transmission power does not exceed a third maximum transmission power that can be used in the communication device,
A communication device. When the transmission means transmits a signal only to one of the base station apparatus and the one or more other base station apparatuses, a third maximum that can be used in the communication apparatus. Transmitting a signal to the one base station apparatus within a range not exceeding the transmission power;
The communication device according to claim 20. A control method for a base station apparatus in a wireless communication system in which a communication apparatus can be connected simultaneously with a base station apparatus and one or more other base station apparatuses,
A determining unit transmits a signal to each of the one or more other base station devices, and a first maximum transmission power that can be used when the communication device transmits a signal to the base station device. The second maximum transmission power that can be used in each case is determined so that the sum of the first maximum transmission power and the second maximum transmission power does not exceed the third maximum transmission power that can be used in the communication device. A decision process to
A notifying step for notifying the first maximum transmission power to the communication device and notifying the second maximum transmission power to each of the one or more other base station devices;
Have
The second maximum transmission power is notified to the communication device in the notification step, or is notified to the communication device from each of the one or more other base station devices.
A control method characterized by that. A control method of a communication device that can be connected simultaneously with a base station device and one or more other base station devices,
The acquisition means acquires information on the first maximum transmission power that can be used for signal transmission to the base station apparatus from the base station apparatus, and the base station apparatus or the one or more other base station apparatuses Obtaining a second maximum transmission power information that can be used to transmit a signal to each of the one or more other base station devices,
When transmitting means transmits signals simultaneously to each of the base station apparatus and the one or more other base station apparatuses, the first maximum transmission power and the second maximum transmission power do not exceed, respectively. A transmission step of transmitting the signal with electric power;
Have
The sum of the first maximum transmission power and the second maximum transmission power does not exceed a third maximum transmission power that can be used in the communication device,
A control method characterized by that. In the wireless communication system in which a communication apparatus can be connected simultaneously with a base station apparatus and one or more other base station apparatuses, the base having notification means for notifying the communication apparatus or the one or more other base station apparatuses In the computer equipped with the station device,
A first maximum transmission power that can be used when the communication device transmits a signal to the base station device, and a communication device that is used when the communication device transmits a signal to each of the one or more other base station devices. A determination step of determining a second maximum transmission power that can be generated so that a sum of the first maximum transmission power and the second maximum transmission power does not exceed a third maximum transmission power that can be used in the communication device; ,
Notifying the communication device of the first maximum transmission power and controlling the notification means to notify the second maximum transmission power to each of the one or more other base station devices;
A program for executing
The second maximum transmission power is notified to the communication apparatus by the notification means, or is notified to the communication apparatus from each of the one or more other base station apparatuses.
A program characterized by that. A computer provided in a communication apparatus that can be connected simultaneously with a base station apparatus and one or more other base station apparatuses and has a transmission means for transmitting a signal to the base station apparatus or the one or more other base station apparatuses ,
From the base station apparatus to obtain information of the first maximum transmission power that can be used for signal transmission to the base station apparatus, and from each of the base station apparatus or the one or more other base station apparatus, An acquisition step of acquiring information of a second maximum transmission power that can be used to transmit a signal to each of the one or more other base station devices;
When transmitting a signal to each of the base station apparatus and the one or more other base station apparatuses at the same time, the signal with power not exceeding the first maximum transmission power and the second maximum transmission power, respectively. Controlling the transmitting means to transmit
A program for executing
The sum of the first maximum transmission power and the second maximum transmission power does not exceed a third maximum transmission power that can be used in the communication device,
A program characterized by that.

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