JP6209458B2 - Mobile station and mobile communication method - Google Patents

Description

  The present invention relates to a mobile station and a mobile communication method.

In the existing LTE (Long Term Evolution) scheme, the mobile station UE has two CC (Carrier Aggregation), such as “UL-MIMO (Uplink-Multi-Input and Multi-Output)” and “2UL CA (Carrier Aggregation)”. (Component Carrier, component carrier) When communication is performed using # 1 / CC # 2, the maximum allowable transmission power value P _CMAX1 / P _CMAX2 in CC # 1 / CC # 2 is set according to an instruction from the network Has been.

The standard of _{"P CMAX"} in the LTE scheme Release-8, as such maximum permitted transmission power value _{P CMAX} is small, tolerance corresponding to the maximum allowable transmission power value _{P CMAX} (allowable variation value of the transmission power) delta increases It is prescribed as follows.

Here, when the mobile station UE performs communication using the two CC # 1 / CC # 2, each of the CC # 1 / CC # 2 is “P _CMAX ” in the Release-8 LTE scheme. According to the regulations, there are cases where the transmission power in the uplink exceeds the upper limit value A of the transmission power in the uplink that is defined in order to avoid the influence of interference. In such a case, it is necessary to reduce the tolerance Δ described above.

For example, as shown in FIG. 8, when each of CC # 1 / CC # 2 _{complies with} the provision of “P _CMAX ” in the Release-8 LTE scheme, under certain transmission conditions, the upper limit of the transmission power in the uplink There are cases where the value A is exceeded (in the example of FIG. 8, 25 dBm).

In order to avoid such a case, simulation calculation is performed so that the transmission power in the uplink does not exceed the upper limit value A of the transmission power in the uplink by reducing the tolerance Δ itself corresponding to the maximum allowable transmission power value P _CMAX. The method is known (for example, refer nonpatent literature 1).

3GPP contribution R4-125826

However, in the above simulation calculation method, the tolerance Δ itself corresponding to the maximum allowable transmission power value P _CMAX may be reduced more than necessary, which may impact the network quality and the battery life of the mobile station UE. There was a problem that there was.

Therefore, the present invention has been made in view of the above-mentioned problems, and the transmission power in the uplink does not exceed the upper limit value A of the transmission power in the uplink, and the tolerance of the tolerance corresponding to the maximum allowable transmission power value P _CMAX is _increased. It is an object of the present invention to provide a mobile station and a mobile communication method capable of minimizing the downshift amount Δ _shift .

  A first feature of the present invention is a mobile station capable of performing communication using a plurality of component carriers in the uplink, and is configured to control transmission power in the uplink The transmission power control unit includes an upper limit value of transmission power in the uplink, a maximum allowable transmission power value in each of the component carriers, and an allowable transmission power corresponding to each of the maximum allowable transmission power values. The gist is that the amount of downshift of the allowable variation value is calculated based on a predetermined algorithm using the variation value.

  A second feature of the present invention is a mobile communication method in which a mobile station performs communication using a plurality of component carriers in the uplink, and the mobile station includes a step of controlling transmission power in the uplink. In the step, the mobile station transmits an upper limit value of transmission power in the uplink, a maximum allowable transmission power value in each of the component carriers, and an allowable variation in transmission power corresponding to each of the maximum allowable transmission power values. The gist is to calculate the amount of downshift of the allowable fluctuation value based on a predetermined algorithm using the value.

As described above, according to the present invention, the transmission down-shift amount Δ _shift corresponding to the maximum permissible transmission power value P _CMAX is set so that the transmission power in the uplink does not exceed the upper limit value A of the transmission power in the uplink. It is possible to provide a mobile station and a mobile communication method that can be minimized.

1 is an overall configuration diagram of a mobile communication system according to a first embodiment of the present invention. FIG. 3 is a functional block diagram of a mobile station according to the first embodiment of the present invention. It is a figure for demonstrating the control method of the transmission power performed by the mobile station which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating the control method of the transmission power performed by the mobile station which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating the control method of the transmission power performed by the mobile station which concerns on the 1st Embodiment of this invention. 3 is a flowchart for explaining an operation of the mobile communication system according to the first embodiment of the present invention. It is a figure for demonstrating the effect of the control method of the transmission power performed by the mobile station which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating a prior art.

(Mobile communication system according to the first embodiment of the present invention)
With reference to FIG. 1 thru | or FIG. 7, the mobile communication system which concerns on the 1st Embodiment of this invention is demonstrated.

  The mobile communication system according to the present embodiment is an LTE (or LTE-Advanced) mobile communication system, and includes a radio base station eNB and a mobile station UE as shown in FIG. .

  In the mobile communication system according to the present embodiment, the mobile station UE is configured to be able to perform communications such as “UL-MIMO” and “2UL CA” using CC # 1 and CC # 2. .

  In the mobile communication system according to the present embodiment, the mobile station UE is configured to be able to perform communication using a plurality of CCs (for example, N CCs). In the specification, the case where the mobile station UE performs communication using two CCs will be described as an example.

  Here, in the mobile communication system according to the present embodiment, CC # 1 and CC # 2 may be CCs under the same radio base station eNB or CCs under different radio base stations eNB. Good.

  As illustrated in FIG. 2, the mobile station UE according to the present embodiment includes a reception unit 11, a transmission power control unit 12, and a transmission unit 13.

  The reception unit 11 is configured to receive various signals from the radio base station eNB, and the transmission unit 13 is configured to transmit various signals to the radio base station eNB.

  For example, the receiving unit 11 is configured to receive a control signal specifying the upper limit value A of transmission power in the uplink from the radio base station eNB.

  Further, the transmission unit 13 is configured to transmit a data signal to the radio base station eNB with transmission power controlled by the transmission power control unit 12.

  The transmission power control unit 12 is configured to control transmission power in the uplink.

Specifically, when the mobile station UE performs communication using CC # 1 and CC # 2 in the uplink, the transmission power control unit 12 performs CC # 1 / CC # based on a predetermined algorithm. 2 to calculate a tolerance downshift amount Δ _shift corresponding to each of the maximum allowable transmission power values P _CMAX1 / P _CMAX2 corresponding to each of the two, and based on the tolerance down shift amount Δ _shift , the transmission power in the uplink is calculated. Is configured to determine.

Here, the predetermined algorithm is the upper limit value A of the transmission power in the uplink, each of the maximum allowable transmission power value P _CMAX1 / P _CMAX2 and the maximum allowable transmission power value P _CMAX1 / P _CMAX2 in each of CC # 1 / CC # 2. The tolerance Δ ₁ / Δ ₂ corresponding to is used.

For example, when the mobile station UE performs communication using CC # 1 / CC # 2 in the uplink, the transmission power control unit 12 is based on a predetermined algorithm defined by the equation shown in FIG. Then, the above-described tolerance downshift amount Δ _shift may be calculated.

Here, “A” is set to the upper limit A of the transmission power in the uplink designated by the network (radio base station eNB) in order to avoid the influence of interference, or set in advance in the mobile station UE for other purposes. _Is the upper limit value A of transmission power in the uplink, “P _CMAX1 ” is the maximum allowable transmission power value in CC # 1, and “P _CMAX2 ” is the maximum allowable transmission power value in CC # 2.

Further, "delta _1" is a tolerance corresponding to the _{"P Cmax1"} (permissible variation value of the transmission power), "delta _2" is a tolerance corresponding to the _{"P Cmax2",} "delta _Shift" is This is a tolerance downshift amount in the uplink.

Here, FIG. 3B shows the relationship between the maximum allowable transmission power value P _CMAX and the tolerance Δ defined in the Release-8 LTE scheme.

In addition, the transmission power control unit 12 sets the upper limit value A of the transmission power in the uplink when the network (radio base station eNB) designates the upper limit value A of the transmission power in the uplink or for other purposes. When preset in the UE, the above-described tolerance downshift amount Δ _shift may be calculated. In such a case, the above predetermined algorithm may be registered in advance in the memory of the mobile station UE.

Alternatively, the transmission power control unit 12 may be configured to calculate the above-described tolerance downshift amount Δ _shift based on a predetermined algorithm when the mobile station UE is designed.

Alternatively, when the predetermined algorithm is registered in the memory, the transmission power control unit 12 may be configured to calculate the above-described tolerance downshift amount Δ _shift based on the predetermined algorithm.

Here, referring to FIG. 4, the transmission power control method by the transmission power control unit 12 in the case where the mobile station UE performs “UL-MIMO” using CC # 1 and CC # 2 (that is, tolerance down) An example of a method for calculating the shift amount Δ _shift will be described.

As shown in FIG. 4, in such a case, CC # 1 and CC # 2 are controlled to have the same maximum allowable transmission power value P _CMAX1 / P _CMAX2 ( _{19.5 dBm in} the example of FIG. 4). .

Here, according to the definition of “P _CMAX ” in the Release-8 LTE scheme, the total value of the maximum allowable transmission power value P _CMAX1 and the maximum allowable transmission power value P _CMAX2 (22.5 dBm in the example of FIG. 4) and Considering the tolerance Δ (upper limit value = + 3.5 dB / lower limit value = −3.5 dB in the example of FIG. 4), the transmission power in the uplink exceeding the upper limit value A (25 dBm in the example of FIG. 4) of the transmission power. Will be allowed.

Therefore, the transmission power control unit 12 calculates the tolerance downshift amount Δ _shift (0.5 dB in the example of FIG. 4) based on a predetermined algorithm, and the upper limit of the tolerance Δ by the tolerance downshift amount Δ _shift. By downshifting the value and the lower limit value (in the example of FIG. 4, upper limit value = + 3.0 dB / lower limit value = −4.0 dB), the transmission power upper limit value A (25 dBm in the example of FIG. 4) or less The transmission power in the uplink can be stored.

Next, referring to FIG. 5, a transmission power control method (that is, tolerance downshift) by the transmission power control unit 12 in a case where the mobile station UE performs “2UL CA” using CC # 1 and CC # 2. An example of a method for calculating the amount Δ _shift will be described.

In such a case, CC # 1 and CC # 2 may be controlled so as to have the same maximum allowable transmission power value P _CMAX1 / P _CMAX2 , or different maximum allowable transmission power values as shown in FIG. (in the example of FIG. 5, 16dBm) P _CMAX1 / (in the example of FIG. 5, 22dBm) _{P CMAX2} may be controlled to be.

Here, according to the definition of “P _CMAX ” in the Release-8 LTE scheme, the total value of the maximum allowable transmission power value P _CMAX1 and the maximum allowable transmission power value P _CMAX2 (22.97 dBm in the example of FIG. 5) and Considering the tolerance Δ (upper limit value = + 2.79 dB / lower limit value = −2.46 dB in the example of FIG. 5), the transmission power in the uplink that exceeds the upper limit value A (25 dBm in the example of FIG. 5) of the transmission power Will be allowed.

Therefore, the transmission power control unit 12 calculates the tolerance downshift amount Δ _shift (0.76 dB in the example of FIG. 5) based on a predetermined algorithm, and the upper limit of the tolerance Δ by the tolerance downshift amount Δ _shift. By downshifting the value and the lower limit value (in the example of FIG. 5, upper limit value = + 2.03 dB / lower limit value = −3.22 dB), the transmission power is lower than the upper limit value A (in the example of FIG. 5, 25 dBm). The transmission power in the uplink can be stored.

  Hereinafter, an example of a specific operation of the mobile communication system according to the present embodiment will be described with reference to FIG.

  As shown in FIG. 6, when the upper limit value A of transmission power is designated from the network (radio base station eNB) in step S101, the mobile station UE needs to change the transmission power in the uplink in step S102. It is determined whether or not there is.

  If it is determined that it is necessary to change the transmission power in the uplink, the operation proceeds to step S103. If it is determined that it is not necessary to change the transmission power in the uplink, the operation is performed in steps The process proceeds to S104.

In step S103, the mobile station UE calculates a down-shift delta _Shift of tolerance, on the basis of the down-shift delta _Shift of such tolerance, sets the transmission power in the uplink.

  On the other hand, in step S104, the mobile station UE maintains the transmission power set at the start of communication.

  In step S105, the mobile station UE performs communication such as “UL-MIMO” or “2UL CA” with the currently set transmission power.

  In step S106, the mobile station UE determines whether or not to continue communication such as “UL-MIMO” or “2UL CA”.

  When it is determined that communication such as “UL-MIMO” or “2UL CA” is to be continued, this operation returns to step S102, and when it is determined that communication such as “UL-MIMO” or “2UL CA” is not continued. The operation proceeds to step S107.

  In step S107, the mobile station UE ends communication such as “UL-MIMO” or “2UL CA”.

FIG. 7 shows changes in the lower limit value of tolerance Δ when using the conventional LTE system (dotted line) and changes in tolerance downshift amount Δ _shift when using the system in the mobile communication system according to the present embodiment (solid line). ).

  As shown in FIG. 7, when the conventional LTE scheme is used, the lower limit value of the tolerance is lowered more than necessary, whereas the scheme in the mobile communication system according to the present embodiment is used. In this case, the downshift of the tolerance lower limit value can be minimized.

  The characteristics of the present embodiment described above may be expressed as follows.

A first feature of the present embodiment is a mobile station UE capable of performing communication using CC # 1 / CC # 2 (component carrier) in the uplink, and configured to control transmission power in the uplink The transmission power control unit 12 is configured such that the transmission power control unit 12 has an upper limit value A for transmission power in the uplink, and a maximum allowable transmission power value P _CMAX1 / P for each of CC # 1 / CC # 2. Based on a predetermined algorithm using tolerance (allowable fluctuation value) Δ ₁ / Δ ₂ corresponding to each of _{CMAX 2} and maximum allowable transmission power value P _{CMAX 1} / P _{CMAX 2} , the tolerance downshift amount Δ _shift is calculated. It is a summary.

  According to such a feature, the transmission power in the uplink of the mobile station UE is limited to the transmission power upper limit value A specified from the network in order to avoid the influence of interference or the like. The downshift of the lower limit value of the tolerance Δ can be minimized without exceeding the set upper limit value A of the transmission power in the uplink.

  As a result, it is possible to minimize the impact on the network quality and the battery life of the mobile station UE while avoiding the influence of interference.

として規定されている所定アルゴリズムに基づいて、上述のトレランスのダウンシフト量Δ_{ｓｈｉｆｔ}を算出するように構成されていてもよい。 In the first feature of the present embodiment, when the mobile station UE performs communication using CC # 1 / CC # 2 in the uplink, the transmission power control unit 12

The tolerance downshift amount Δ _shift described above may be calculated based on a predetermined algorithm defined as:

According to this feature, the mobile station UE can efficiently calculate the optimum tolerance downshift amount Δ _shift as shown in FIG. 7 by using a predetermined algorithm defined by the mathematical expression. .

In the first feature of the present embodiment, the transmission power control unit 12 sets the above upper limit value A in advance in the mobile station UE when the above upper limit value A is designated by the network or for other purposes. In this case, the above-described tolerance downshift amount Δ _shift may be calculated.

According to this feature, the mobile station UE calculates the tolerance downshift amount Δ _shift as described above, as compared with the case where the tolerance downshift amount Δ _shift is registered in advance, as compared with the case where the tolerance downshift amount Δ _shift is registered in advance. The size can be reduced.

A second feature of the present embodiment is a mobile communication method in which the mobile station UE performs communication using CC # 1 and CC # 2 in the uplink, and the mobile station UE controls transmission power in the uplink. In this step, the mobile station UE transmits the upper limit value A of the transmission power in the uplink, the maximum allowable transmission power value P _CMAX1 / P _CMAX2 in each of CC # 1 / CC # 2, and the maximum allowable value. The gist is to calculate the downshift amount Δ _shift of the allowable fluctuation value based on a predetermined algorithm using the allowable fluctuation value Δ ₁ / Δ ₂ of the transmission power corresponding to each of the transmission power values P _CMAX1 / P _{CMAX 2} .

  Note that the operations of the mobile station UE and the radio base station eNB described above may be implemented by hardware, may be implemented by a software module executed by a processor, or may be implemented by a combination of both. .

  The software module includes a RAM (Random Access Memory), a flash memory, a ROM (Read Only Memory), an EPROM (Erasable Programmable ROM), an EEPROM (Electronically Erasable and Programmable ROM, a hard disk, a registerable ROM, a hard disk). Alternatively, it may be provided in a storage medium of an arbitrary format such as a CD-ROM.

  Such a storage medium is connected to the processor so that the processor can read and write information from and to the storage medium. Further, such a storage medium may be integrated in the processor. Such a storage medium and processor may be provided in the ASIC. Such an ASIC may be provided in the mobile station UE and the radio base station eNB. Moreover, this storage medium and processor may be provided in the mobile station UE and the radio base station eNB as a discrete component.

  Although the present invention has been described in detail using the above-described embodiments, it is obvious to those skilled in the art that the present invention is not limited to the embodiments described in this specification. The present invention can be implemented as modified and changed modes without departing from the spirit and scope of the present invention defined by the description of the scope of claims. Therefore, the description of the present specification is for illustrative purposes and does not have any limiting meaning to the present invention.

eNB ... radio base station UE ... mobile station 11 ... reception unit 12 ... transmission power control unit 13 ... transmission unit

Claims (4)

A mobile station capable of performing communication using a plurality of component carriers in the uplink,
A transmission power control unit configured to control transmission power in the uplink,
When the mobile station performs communication using the first component carrier and the second component carrier in the uplink, the transmission power control unit sets the upper limit value of transmission power in the uplink to “A”, and The maximum allowable transmission power value in the first component carrier is “P _CMAX1 ”, the maximum allowable transmission power value in the second component carrier is “P _CMAX2 ”, and the allowable fluctuation value of the transmission power corresponding to the “P _CMAX1 ” is When “Δ ₁ ” is set and the allowable variation value of the transmission power corresponding to “P _CMAX2 ” is “Δ ₂ ” , a value based on (P _CMAX1 + Δ ₁ ) and a value based on (P _CMAX2 + Δ ₂ ) Determines the common logarithm of the sum of the difference between the predetermined integral multiple of the the normally for logarithm and the upper limit value "a", the downshift quantity of the allowable variation value "delta _Shif A mobile station, characterized in that it is configured to calculate as _t ' . Before Symbol transmission power control unit,

The mobile station according to claim 1, based on prescribed have luer algorithm, characterized in that it is configured to calculate the "delta _Shift" downshift amount of the allowable variation value as. When the upper limit value “A” is designated by the network, or when the upper limit value “ A ” is preset for other purposes, the transmission power control unit is configured to reduce the amount of downshift of the allowable variation value. The mobile station according to claim 1, wherein the mobile station is configured to calculate “Δ _shift ” . A mobile communication method in which a mobile station performs communication using a plurality of component carriers in an uplink,
The mobile station has a step of controlling transmission power in the uplink;
The mobile station, when performing communication using a first component carrier and the second component carrier in the uplink, in the step, the mobile station, the upper limit of the transmission power in said uplink link is "A" The maximum allowable transmission power value in the first component carrier is “P _CMAX1 ”, the maximum allowable transmission power value in the second component carrier is “P _CMAX2 ”, and the allowable variation in the transmission power corresponding to the “P _CMAX1 ” When the value is “Δ ₁ ” and the allowable fluctuation value of the transmission power corresponding to “P _CMAX2 ” is “Δ ₂ ”, the value is based on (P _CMAX1 + Δ ₁ ) and (P _CMAX2 + Δ ₂ ). The common logarithm of the sum with the value is obtained, and the difference between the upper limit value “A” and a value that is a predetermined integer multiple of the common logarithm is calculated as the downshift amount “Δ of the allowable fluctuation value. A mobile communication method characterized by calculating as “ _shift ” .

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