JP2011250479A - Mobile communication method and mobile station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide quick and appropriate scheduling for a UL CC which is associated with the power headroom calculated on the basis of path loss assumed from a new DL CC, when the new DL CC is added in carrier aggregation (CA) communication.SOLUTION: A mobile communication method according to the invention includes: a step in which a radio base station eNB transmits an "RRC Connection Reconfiguration" that indicates addition of a new DL CC to a mobile station UE; a step in which the mobile station UE calculates the power headroom on the basis of path loss assumed from the new DL CC in response to the "RRC Connection Reconfiguration"; and a step in which the mobile station UE transmits a "MAC Control Element" that includes the power headroom to the radio base station eNB.

Description

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

  In the LTE (Long Term Evolution) scheme, the mobile station UE makes a PHR including a power headroom via a PUSCH (Physical Uplink Shared Channel, uplink shared channel) according to a predetermined transmission trigger to the radio base station eNB. It is configured to transmit (Power headroom report).

  Here, Power headroom is difference information between an estimated value of required transmission power and maximum transmission power in PUSCH for the mobile station UE. In addition, the required transmission power in such PUSCH is configured to be calculated based on a path loss estimated from the downlink.

  When the mobile station UE actually estimates a path loss from the downlink, the mobile station UE transmits the downlink common pilot signal (cell-specific reference signal) in the radio base station eNB (Resource Element unit) and the downlink common in the mobile station UE. The path loss is calculated based on the difference from the received power (Resource Element unit) of the pilot signal.

  The radio base station eNB is configured to grasp how much transmission power is available in the mobile station UE based on the PHR and to allocate uplink resources to the mobile station UE.

3GPP TS36.133 3GPP TS 36.213 3GPP TS36.321

  In the LTE-Advanced scheme, which is a successor scheme of the LTE scheme, the mobile station UE is connected to the radio base station eNB with a plurality of DL CCs (Downlink Component Carriers) and a plurality of UL CCs (with different carrier frequencies). It is configured to perform CA (Carrier Aggregation) communication using an Uplink Component Carrier (uplink carrier).

  Here, in such CA communication, in a case where a new DL CC is added, a case where a DL CC in an inactive state is changed to an active state, the radio base station eNB is based on a path loss estimated from the DL CC. Until the calculated power headroom is received, the transmission power that can be used in the UL CC related to the power headroom cannot be grasped, and thus there is a problem that appropriate scheduling in the UL CC cannot be performed. .

  Specifically, since the path loss in each CC may be different, for each UL CC used for CA communication with the mobile station UE, the path loss used by the mobile station UE to control the transmission power in each UL CC. Is reported from the radio base station eNB to the mobile station UE as to which DL CC should be estimated.

  For example, when the radio base station eNB performs CA communication with the mobile station UE according to the CC configuration in FIG. 1, in the same path loss environment as the UL PCC and DL PCC, UL SCC # 1 and UL SCC # 2 and DL SCC # 1 and DL SCC # 2 are in the same path loss environment (different from UL PCC and DL PCC), the radio base station eNB controls the transmission power in the UL PCC for the mobile station UE The path loss used for the transmission should be estimated from the DL PCC, and the path loss used for controlling the transmission power in the UL SCC # 1 and the UL SCC # 2 should be estimated from the DL SCC # 1 or DL SCC # 2. To be notified. If the path loss in each CC is different, the mobile station UE should use the radio base station eNB to estimate the path loss so that the radio base station eNB can appropriately perform uplink resource allocation in each UL CC. It is necessary to transmit independent power headrooms corresponding to the number of notified DL CCs to the radio base station eNB.

  In the above-described example, the mobile station UE uses the power headroom calculated from the required transmission power in the PUSCH in the UL PCC calculated based on the path loss estimated from the DL PCC, and the DL SCC # 1 or DL SCC # 2. It is necessary to transmit to the radio base station eNB the Power Headroom calculated from the required transmission power in the PUSCH in UL SCC # 1 and UL SCC # 2 calculated based on the estimated path loss.

  Then, the radio base station eNB uses the uplink power in the UL PCC based on the power headroom calculated from the required transmission power in the PUSCH in the UL PCC calculated based on the path loss estimated by the mobile station UE from the DL PCC. Based on the Power Headroom obtained from the required transmission power in PUSCH in UL SCC # 1 and UL SCC # 2 that is allocated based on the path loss estimated by the mobile station from DL SCC # 1 or DL SCC # 2 Thus, uplink resource allocation is performed in UL SCC # 1 and UL SCC # 2.

  However, in such CA communication, in a case where a new DL CC is added or a case where a DL CC in an inactive state is changed to an active state, the radio base station eNB performs power calculation based on the path loss in the DL CC. Until the headroom is received, the transmission power that can be used in the UL CC related to the power headroom cannot be grasped, so that there is a problem in that appropriate scheduling in the UL CC cannot be performed.

  Therefore, the present invention has been made in view of the above-described problems, and is estimated from a DL CC in a case where a new DL CC is added or a DL CC in an inactive state is changed to an active state in CA communication. It is an object of the present invention to provide a mobile communication method and a mobile station that can quickly perform appropriate scheduling in a UL CC related to a power headroom calculated based on a path loss.

  A first feature of the present invention is a mobile communication method in which a mobile station performs communication using a plurality of downlink carriers and a plurality of uplink carriers having different carrier frequencies with a radio base station, A step in which a radio base station transmits an instruction signal instructing the mobile station to add a new downlink carrier, and the mobile station is estimated from the new downlink carrier according to the instruction signal Calculating the difference information between the estimated value of the required transmission power in the uplink shared channel and the maximum transmission power of the mobile station based on the path loss, and the mobile station And a step of transmitting control information including information.

  A second feature of the present invention is a mobile communication method in which a mobile station performs communication using a plurality of downlink carriers and a plurality of uplink carriers having different carrier frequencies with a radio base station, A step in which a radio base station transmits an instruction signal instructing the mobile station to change a predetermined downlink carrier to an active state; and the mobile station responds to the instruction signal and the predetermined downlink carrier Calculating a difference information between an estimated value of required transmission power in the uplink shared channel and the maximum transmission power of the mobile station based on the path loss estimated from the mobile station, and the mobile station to the radio base station And a step of transmitting control information including the difference information.

  A third feature of the present invention is a mobile station configured to be able to perform communication using a plurality of downlink carriers and a plurality of uplink carriers having different carrier frequencies with a radio base station. A receiving unit configured to receive an instruction signal instructing addition of a new downlink carrier from the radio base station, and a path loss estimated from the new downlink carrier according to the instruction signal A calculation unit configured to calculate difference information between an estimated value of required transmission power in the uplink shared channel and the maximum transmission power of the mobile station, and The gist of the present invention is to include a transmission unit configured to transmit control information including difference information.

  A fourth feature of the present invention is a mobile station configured to be able to communicate with a radio base station using a plurality of downlink carriers and a plurality of uplink carriers having different carrier frequencies. A receiving unit configured to receive from the radio base station an instruction signal instructing a change to an active state of a predetermined downlink carrier; and from the predetermined downlink carrier according to the instruction signal Based on the estimated path loss, a calculation unit configured to calculate difference information between an estimated value of required transmission power in the uplink shared channel and the maximum transmission power of the mobile station, and the radio base station On the other hand, the gist of the present invention is to include a transmission unit configured to transmit control information including the difference information.

  As described above, according to the present invention, in CA communication, in a case where a new DL CC is added or a case where a DL CC in an inactive state is changed to an active state, calculation is performed based on the path loss in the DL CC. It is possible to provide a mobile communication method and a mobile station that can quickly and appropriately perform scheduling in the UL CC related to the power headroom.

It is a figure for demonstrating CA communication currently performed with the mobile communication system which concerns on the 1st Embodiment of this invention. FIG. 3 is a functional block diagram of a mobile station according to the first embodiment of the present invention. FIG. 3 is a functional block diagram of a radio base station according to the first embodiment of the present invention. FIG. 3 is a sequence diagram showing an operation of the mobile communication system according to the first embodiment of the present invention. FIG. 3 is a sequence diagram showing an operation of the mobile communication system according to the first embodiment of the present invention.

(Mobile communication system according to the first embodiment of the present invention)
The configuration of the mobile communication system according to the first embodiment of the present invention will be described with reference to FIG. 1 to FIG.

  The mobile communication system according to the present embodiment is an LTE-Advanced mobile communication system. In the mobile communication system according to the present embodiment, the mobile station UE has a different carrier frequency from the radio base station eNB. It is comprised so that CA communication can be performed using several CC.

  Further, in the mobile communication system according to the present embodiment, as shown in FIG. 1, the mobile station UE includes an UL PCC (Uplink Primary Component Carrier), an UL SCC (Uplink Secondary Component Carrier) # 1, and an UL SCC # 2. It is assumed that CA communication is performed using DL PCC (Downlink Primary Component Carrier), DL SCC # 1, and DL SCC # 2.

  As shown in FIG. 2, the mobile station UE includes a transmission unit 11, a CA control unit 12, a power headroom calculation unit 13, and a reception unit 14.

  The receiving unit 11 is configured to receive a signal transmitted by the radio base station eNB.

  For example, the receiving unit 11 is configured to receive an RRC message such as “RRC Connection Reconfiguration” instructing addition of a new DL CC from a radio base station.

  In addition, the reception unit 11 is configured to receive a MAC signal such as “Active DL CC # X” that instructs to change the predetermined DL CC to the active state from the radio base station.

  The CA control unit 12 is configured to perform control related to CA communication by the mobile station UE.

  For example, when the mobile station UE performs CA communication, the CA control unit 12 adds a new CC in the RRC layer according to an instruction (specifically, an RRC message) from the radio base station eNB. The existing CC can be deleted, or the PCC can be changed.

  In addition, when the mobile station UE is performing CA communication, the CA control unit 12 performs CA communication in the MAC layer in accordance with an instruction from the radio base station eNB (specifically, “MAC Control Element”). It is configured to set the state (active state or inactive state) of each CC used in FIG.

  The power head calculation unit 14 is configured to calculate a power head based on a path loss estimated from a predetermined DL CC.

  For example, the power headroom calculation unit 14 is configured to calculate the power headroom based on the path loss estimated from the DL CC newly added by the CA control unit 12.

  Further, the power headroom calculation unit 14 is configured to calculate the power headroom based on the path loss estimated from the predetermined DL CC that has been changed to the active state.

  The transmission unit 14 is configured to transmit a signal to the radio base station eNB.

  For example, the transmission unit 14 is configured to transmit “MAC Control Element (PHR)” including the above-mentioned power headroom to the radio base station eNB.

  As illustrated in FIG. 3, the radio base station eNB includes a transmission unit 21, a reception unit 22, a CA control unit 23, and a scheduling unit 24.

  The transmission unit 21 is configured to transmit a signal to the mobile station UE. For example, the transmission unit 21 instructs the mobile station UE to change an RRC message such as “RRC Connection Reconfiguration” instructing addition of a new DL CC, or to change an active state of a predetermined DL CC to “Active DL CC #”. It is configured to transmit a MAC signal such as “X”.

  The receiving unit 22 is configured to receive a signal transmitted by the mobile station UE.

  For example, the receiving unit 22 is configured to receive a “MAC Control Element (PHR)” including a power headroom from the mobile station UE. Here, the receiving unit 22 is configured to receive PHRs corresponding to the number of DL CCs used in CA communication by the mobile station UE.

  Further, the receiving unit 22 may be configured to receive only PHRs corresponding to the number of DL CCs used by the mobile station UE for path loss estimation.

  The CA control unit 23 is configured to perform control related to CA communication by the mobile station UE.

  For example, the CA control unit 23 uses the RRC message (for example, “RRC Reconfiguration” message or the like) in the RRC layer to add a new CC or an existing one to the mobile station UE performing CA communication. It is configured to be able to instruct deletion of the CC or change of the PCC.

  Here, after the mobile station UE transitions from the RRC_Idle state to the RRC_Connected state and starts communication using one DL CC and one UL CC, as in the LTE (Release8 / 9) method, the CA control is performed. The unit 23 is configured to instruct addition of the second and subsequent DL CCs and UL CCs using the RRC message in the RRC layer.

  Further, for example, the CA control unit 23 is configured to instruct setting of the state (active state or inactive state) of each CC used in CA communication by using “MAC Control Element” in the MAC layer. Has been.

  The scheduling unit 24 is configured to perform a scheduling process for the mobile station UE based on the PHR received by the receiving unit 22.

  For example, based on such PHR, the scheduling unit 24 assigns RB (Resource Block) in PUSCH, assigns TBS (Transport Block Size) in PUSCH, determines whether TTI bundling is applied, and performs SRS (Sounding). (Reference Signal) transmission bandwidth is determined.

  Hereinafter, the operation of the mobile communication system according to the present embodiment will be described with reference to FIG. 4 and FIG.

  First, as shown in FIG. 4, in step S1001, the radio base station eNB transmits “RRC Connection Reconfiguration” instructing addition of a new DL CC to the mobile station UE performing CA communication. .

  In step S1002, the mobile station UE calculates a power headroom based on the path loss estimated from the newly added DL CC in accordance with the “RRC Connection Reconfiguration”, and the power base station eNB transmits the power headroom to the power base station eNB. “MAC Control Element (PHR)” including the headroom is transmitted.

  Second, as illustrated in FIG. 5, in step S2001, the radio base station eNB instructs the mobile station UE performing CA communication to change the existing DL CC to the active state. CC # X "is transmitted.

  In step S2002, the mobile station UE calculates the power headroom based on the path loss estimated from the DL CC that has been changed to the active state in accordance with the “Active DL CC # X”, and the radio base station eNB , And transmits “MAC Control Element (PHR)” including such Power headroom.

  According to the mobile communication system according to the present embodiment, the mobile station UE instructs “RRC Connection Reconfiguration” for instructing addition of a new DL CC or “Active DL CC # X for instructing change of an existing DL CC to an active state”. ”Is received, the power headroom calculated based on the path loss estimated from the DL CC is immediately transmitted to the radio base station eNB. Appropriate scheduling in the UL CC related to the power headroom can be quickly performed.

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

  The first feature of the present embodiment is that the mobile station UE uses a plurality of DL CCs (downlink carriers) and a plurality of UL CCs (uplink carriers) having different carrier frequencies with the radio base station eNB. A mobile communication method for performing CA communication, in which the radio base station eNB transmits “RRC Connection Reconfiguration (instruction signal)” instructing the mobile station UE to add a new DL CC; and the mobile station UE Is based on the path loss estimated from the new DL CC according to “RRC Connection Reconfiguration”, and the difference information between the estimated value of the required transmission power in the PUSCH (uplink shared channel) and the maximum transmission power of the mobile station UE Calculating (Power headroom) and the mobile station U But the radio base station eNB, and summarized in that a step of transmitting a "MAC Control Element (control information)" including the Power headroom.

  The second feature of the present embodiment is a mobile communication method in which the mobile station UE performs CA communication using a plurality of DL CCs and a plurality of UL CCs having different carrier frequencies with the radio base station eNB. The radio base station eNB transmits “Active DL CC # X (instruction signal)” instructing the mobile station UE to change the predetermined DL CC to the active state, and the mobile station UE performs “Active In accordance with “DL CC # X”, a step of calculating a power headroom based on a path loss estimated from a predetermined DL CC, and the mobile station UE transmits a “MAC Control Element” including the power headroom to the radio base station eNB. And a step of transmitting "."

  The third feature of the present embodiment is that the mobile station is configured to be able to perform CA communication using a plurality of DL CCs and a plurality of UL CCs having different carrier frequencies with the radio base station eNB. In response to the reception unit 12 that is a UE and is configured to receive “RRC Connection Reconfiguration” instructing addition of a new DL CC from the radio base station eNB, and according to the “RRC Connection Reconfiguration”, the new DL CC Based on the path loss estimated from the above, a power headroom calculating unit 14 configured to calculate a power headroom and a “MAC Control Element” including the power headroom are transmitted to the radio base station eNB. And gist to a transmission unit 11 that is configured to.

  A fourth feature of the present embodiment is that the mobile station is configured to be able to perform CA communication using a plurality of DL CCs and a plurality of UL CCs having different carrier frequencies with the radio base station eNB. A receiving unit 12 configured to receive an “Active DL CC # X” instructing a change from a radio base station eNB to an active state of a predetermined DL CC; and an “Active DL CC # X” ”Based on the path loss estimated from the predetermined DL CC, the power headroom calculating unit 14 configured to calculate the power headroom, and“ MAC Control including the power headroom to the radio base station eNB ”. A transmission unit 11 configured to transmit an “Element”. The the gist.

  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 or the radio base station eNB. Further, the storage medium and the processor may be provided as a discrete component in the mobile station UE or the radio base station eNB.

  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.

UE ... mobile station eNB ... radio base station 14, 21 ... transmitting unit 11, 22 ... receiving unit 12, 23 ... CA control unit 13 ... Power headroom calculating unit 24 ... scheduling unit

Claims (4)

A mobile station is a mobile communication method for performing communication using a plurality of downlink carriers and a plurality of uplink carriers having different carrier frequencies with a radio base station,
The radio base station transmitting an instruction signal instructing the mobile station to add a new downlink carrier;
Based on the path loss estimated from the new downlink carrier by the mobile station according to the instruction signal, difference information between an estimated value of required transmission power in the uplink shared channel and the maximum transmission power of the mobile station Calculating
And a step of transmitting the control information including the difference information to the radio base station. A mobile station is a mobile communication method for performing communication using a plurality of downlink carriers and a plurality of uplink carriers having different carrier frequencies with a radio base station,
The radio base station transmitting an instruction signal instructing the mobile station to change a predetermined downlink carrier to an active state;
Based on the path loss estimated from the predetermined downlink carrier by the mobile station according to the instruction signal, difference information between an estimated value of required transmission power in the uplink shared channel and the maximum transmission power of the mobile station Calculating
And a step of transmitting the control information including the difference information to the radio base station. A mobile station configured to be able to perform communication with a radio base station using a plurality of downlink carriers and a plurality of uplink carriers having different carrier frequencies,
A receiving unit configured to receive an instruction signal instructing addition of a new downlink carrier from the radio base station;
In accordance with the instruction signal, based on a path loss estimated from the new downlink carrier, difference information between an estimated value of required transmission power in the uplink shared channel and the maximum transmission power of the mobile station is calculated. A configured calculation unit; and
A mobile station comprising: a transmission unit configured to transmit control information including the difference information to the radio base station. A mobile station configured to be able to perform communication with a radio base station using a plurality of downlink carriers and a plurality of uplink carriers having different carrier frequencies,
A receiving unit configured to receive an instruction signal instructing a change to an active state of a predetermined downlink carrier from the radio base station;
In accordance with the instruction signal, based on a path loss estimated from the predetermined downlink carrier, difference information between an estimated value of required transmission power in the uplink shared channel and the maximum transmission power of the mobile station is calculated. A configured calculation unit; and
A mobile station comprising: a transmission unit configured to transmit control information including the difference information to the radio base station.

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