JP2013062848A - Reference signal transmission method, mobile station device and base station device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use a wireless resource for use in transmission of SRS efficiently.SOLUTION: A scheduling grant including a transmission instruction of SRS (Sounding Reference Signal) is transmitted from a base station device eNodeB and, in response to the scheduling grant, SRS is transmitted from a mobile station device UE. The SRS includes a subframe of PUSCH (Physical Uplink Shared Channel), transmission of which is instructed by the scheduling grant, or a subframe after a predetermined number of subframes from the subframe of PUSCH, and is transmitted in an earliest subframe capable of SRS transmission.

Description

  The present invention relates to a reference signal transmission method, a mobile station apparatus, and a base station apparatus, and more particularly to a reference signal transmission method, a mobile station apparatus, and a base station apparatus in a next-generation mobile communication system.

  In a UMTS (Universal Mobile Telecommunications System) network, HSDPA (High Speed Downlink Packet Access) and HSUPA (High Speed Uplink Packet Access) are adopted for the purpose of improving frequency utilization efficiency and data rate. A system based on CDMA (Wideband Code Division Multiple Access) is maximally extracted. For this UMTS network, Long Term Evolution (LTE) has been studied for the purpose of further high data rate and low delay (for example, see Non-Patent Document 1).

  The third generation system can realize a transmission rate of about 2 Mbps at the maximum on the downlink using a fixed band of 5 MHz in general. On the other hand, in the LTE system, a maximum transmission rate of about 300 Mbps on the downlink and about 75 Mbps on the uplink can be realized using a variable band of 1.4 MHz to 20 MHz. In addition, in the UMTS network, a successor system of LTE is also being studied for the purpose of further increasing the bandwidth and speed (for example, LTE Advanced (LTE-A)). For example, in LTE-A, it is planned to extend the maximum system band of LTE specifications, 20 MHz, to about 100 MHz.

  In an LTE system (LTE system), a base station apparatus measures uplink channel quality based on channel quality measurement SRS (Sounding Reference Signal) transmitted from the mobile station apparatus, and the mobile station apparatus transmits data. Scheduling for transmitting a channel signal (PUSCH: Physical Uplink Shared Channel) is performed, and an instruction is given by PDCCH (Physical Downlink Control Channel). In this case, the channel quality measurement SRS is multiplexed with the final symbol of the subframe constituting the uplink radio frame, and is periodically transmitted from the mobile station apparatus to the base station apparatus at intervals of 5 msec.

3GPP, TR25.912 (V7.1.0), "Feasibility study for Evolved UTRA and UTRAN", Sept. 2006

  However, in the LTE system, the SRS is periodically transmitted to the base station apparatus even when there is no data channel signal (PUSCH) transmitted from the mobile station apparatus in the uplink. For this reason, radio resources used for SRS transmission are fixedly used regardless of the presence or absence of the data channel signal (PUSCH), and there is a problem that it is difficult to use radio resources efficiently.

  The present invention has been made in view of such problems, and provides a reference signal transmission method, a mobile station apparatus, and a base station apparatus that can efficiently use radio resources used for SRS transmission. For the purpose.

  The reference signal transmission method of the present invention includes a step of transmitting a scheduling grant including a transmission instruction of an SRS (Sounding Reference Signal) from a base station apparatus, and an SRS according to the transmission instruction of the SRS included in the scheduling grant from the mobile station apparatus. The step of transmitting is provided.

  The reference signal transmission method of the present invention includes a step of transmitting an uplink scheduling grant including a transmission instruction of an SRS (Sounding Reference Signal) from a base station apparatus, and a transmission instruction of an SRS included in the uplink scheduling grant from a mobile station apparatus. And a step of transmitting the SRS in response.

  According to this method, since the SRS is transmitted from the mobile station apparatus in response to the SRS transmission instruction included in the uplink scheduling grant, it is possible to dynamically control the subframe in which the SRS is multiplexed. It is possible to efficiently use radio resources used for SRS transmission.

  The mobile station apparatus according to the present invention includes a receiving unit that receives an uplink scheduling grant including an SRS transmission instruction from the base station apparatus, and uses the SRS as a predetermined symbol according to the SRS transmission instruction included in the uplink scheduling grant. And multiplexing means for multiplexing, and transmission means for transmitting the SRS multiplexed by the multiplexing means to the base station apparatus.

  According to this configuration, since the SRS is transmitted only when the uplink scheduling grant notification including the SRS transmission instruction is received, the subframe in which the SRS is multiplexed can be dynamically controlled. Thus, it is possible to efficiently use radio resources used for SRS transmission.

  The base station apparatus of the present invention includes a generating unit that generates an uplink scheduling grant including an SRS transmission instruction, and a transmitting unit that transmits the uplink scheduling grant generated by the generating unit to a mobile station apparatus. It is characterized by.

  According to this configuration, since the uplink scheduling grant including the SRS transmission instruction is transmitted, it is possible to instruct the transmission of the SRS by the uplink scheduling grant. Therefore, the subframe in which the SRS is multiplexed is dynamically changed. Since it can control, it becomes possible to use efficiently the radio | wireless resource used for transmission of SRS.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the reference signal transmission method, mobile station apparatus, and base station apparatus which can use efficiently the radio | wireless resource used for transmission of SRS.

It is a figure for demonstrating the transmission method of SRS in a LTE system. It is a figure for demonstrating SRS transmitted with the reference signal transmission method which concerns on the 1st aspect of this invention. It is a figure for demonstrating SRS transmitted with the reference signal transmission method which concerns on the 2nd aspect of this invention. It is a figure for demonstrating SRS transmitted with the reference signal transmission method which concerns on the 3rd aspect of this invention. It is a figure for demonstrating the sub-frame with which SRS was multiplexed in the reference signal transmission method which concerns on a 4th aspect. It is a figure for demonstrating the symbol by which SRS is multiplexed with the reference signal transmission method which concerns on the 4th aspect of this invention. It is a figure for demonstrating the sub-frame with which SRS was multiplexed in the reference signal transmission method which concerns on a 1st aspect. It is a figure for demonstrating the symbol by which SRS is multiplexed with the reference signal transmission method which concerns on the 5th aspect of this invention. It is a figure for demonstrating the symbol by which SRS is multiplexed with the reference signal transmission method which concerns on the 6th aspect of this invention. It is a figure for demonstrating the symbol by which SRS is multiplexed with the reference signal transmission method which concerns on the 7th aspect of this invention. It is a figure for demonstrating the symbol by which SRS is multiplexed with the reference signal transmission method which concerns on the 8th aspect of this invention. It is a figure for demonstrating the structure of the mobile communication system which concerns on one embodiment of this invention. It is a block diagram which shows the whole structure of the mobile station apparatus which concerns on the said embodiment. It is a block diagram which shows the whole structure of the base station apparatus which concerns on the said embodiment. It is a functional block diagram of the baseband signal processing part which the mobile station apparatus which concerns on the said embodiment has. It is a functional block diagram of the baseband signal processing part which the base station apparatus which concerns on the said embodiment has. It is a figure for demonstrating the symbol by which SRS is multiplexed with the reference signal transmission method which concerns on the 9th aspect of this invention. It is a figure for demonstrating the symbol by which SRS is multiplexed with the reference signal transmission method which concerns on the 10th aspect of this invention. It is a figure for demonstrating the scheduling grant transmitted with the reference signal transmission method which concerns on the 11th aspect of this invention. It is a figure for demonstrating the transmission power information and the extended transmission power control information transmitted with the reference signal transmission method which concerns on the 11th aspect of this invention. It is a figure for demonstrating SRS transmitted with the reference signal transmission method which concerns on the 11th aspect of this invention. It is a functional block diagram of the baseband signal processing part which the mobile station apparatus which concerns on the example of a change of this invention has. It is a functional block diagram of the baseband signal processing part which the base station apparatus which concerns on the example of a change of this invention has.

  FIG. 1 is a diagram for explaining a method of transmitting an SRS (Sounding Reference Signal) in the LTE system. As shown in FIG. 1, in the LTE system, SRS for channel quality measurement is multiplexed on the last symbol of subframes (subframes #n to # n + 9) constituting an uplink (UL) radio frame, It is periodically transmitted from the mobile station apparatus UE to the base station apparatus eNodeB at intervals of 5 msec. FIG. 1 shows a case where SRS is multiplexed on the final symbols of subframes # n + 1 and # n + 6.

  On the other hand, the data channel signal (PUSCH: Physical Uplink Shared Channel) is uplinked after 4 TTI (Transmission Time Interval) after receiving an uplink (UL) scheduling grant notification through PDCCH (Physical Downlink Control Channel). Sent by Here, the subframe is a transmission time unit of one data packet subjected to error correction coding (channel coding), and is equal to 1 TTI. For this reason, when receiving a UL scheduling grant notification, PUSCH is transmitted after 4 subframes. In FIG. 1, UL scheduling grants are reported in subframes #m to # m + 2 and # m + 4 among subframes (subframes #m to # m + 9) constituting a downlink (DL) radio frame, A case is shown in which PUSCH is transmitted in uplink (UL) subframes # n + 4 to # n + 6 and # n + 8 according to these UL scheduling grants.

  As shown in FIG. 1, since SRS is transmitted regardless of the presence or absence of PUSCH transmitted in each subframe, even if there is no notification of UL scheduling grant and PUSCH is not transmitted, uplink ( (UL) is periodically transmitted to the base station apparatus eNodeB. From the viewpoint of efficiently using radio resources, it is preferable that the SRS for the purpose of measuring channel quality in the base station apparatus eNodeB is measured when PUSCH is transmitted. However, in the LTE system, since radio resources used for SRS transmission are fixedly used regardless of the presence or absence of PUSCH, it is difficult to efficiently use radio resources. The inventors of the present invention have made the present invention by paying attention to the fact that wireless resources are wasted by transmitting SRS regardless of the presence or absence of PUSCH.

  That is, in the reference signal transmission method according to the present invention, it is possible to efficiently control the radio resources used for SRS transmission by dynamically controlling whether or not SRS is transmitted instead of periodically transmitting SRS. It is intended for use. More specifically, by instructing the mobile station apparatus UE to transmit SRS with a UL scheduling grant that instructs transmission of PUSCH, a subframe in which SRS is multiplexed is dynamically controlled and used for SRS transmission. This makes it possible to use radio resources efficiently.

  In the reference signal transmission method according to the present invention, one bit (hereinafter, referred to as “transmission on / off”) for identifying the presence / absence of transmission of SRS in the mobile station apparatus UE (transmission on / off) in the UL scheduling grant notified by the PDCCH from the base station apparatus eNodeB "Transmission identification bit"). In the mobile station apparatus UE, the transmission timing of SRS is dynamically controlled according to this transmission identification bit. As a result, since the subframe in which the SRS is multiplexed can be dynamically controlled according to the transmission identification bit of the UL scheduling grant, it is possible to efficiently use radio resources used for SRS transmission. .

  In the reference signal transmission method according to the first aspect of the present invention, a base station apparatus eNodeB selects a UL scheduling grant that assigns “1” indicating transmission on to a transmission identification bit, and the SRS of the SRS is selected by the selected UL scheduling grant. The mobile station apparatus UE is instructed whether or not to transmit, and the mobile station apparatus UE transmits the SRS in the same subframe as the PUSCH in which transmission is instructed by the UL scheduling grant including this transmission identification bit.

  FIG. 2 is a diagram for explaining the SRS transmitted by the reference signal transmission method according to the first aspect. In FIG. 2, in the base station apparatus eNodeB, the UL scheduling grant of subframes #m and # m + 4 is selected as the UL scheduling grant including the SRS transmission instruction (that is, the transmission ON transmission identification bit). Shows about. When receiving the notification of the UL scheduling grant including the SRS transmission instruction, the mobile station apparatus UE transmits the SRS together with the PUSCH to be transmitted in subframes # n + 4 and # n + 8 after four subframes according to the UL scheduling grant. Transmit to device eNodeB.

  In the reference signal transmission method according to the first aspect, since the SRS is transmitted in the same subframe as the PUSCH for which transmission is instructed by the UL scheduling grant including the transmission instruction, the last of the subframes # n + 4 and # n + 8 Multiplexed into a symbol. That is, SRS is continuously multiplexed after PUSCH assigned to subframes # n + 4 and # n + 8. In the base station apparatus eNodeB, the channel quality is measured based on the SRS continuously multiplexed on the PUSCH in this way, and scheduling for PUSCH transmission in the mobile station apparatus UE is performed. For this reason, since the channel quality at the timing when PUSCH is actually transmitted can be measured, it is possible to perform scheduling reflecting the actual channel state.

  The UL scheduling grant including the SRS transmission instruction in the base station apparatus eNodeB is selected in consideration of the presence or absence of an interval with the UL scheduling grant including the SRS transmission instruction transmitted in advance. For example, when a certain interval (for example, 4 TTI) has passed since the UL scheduling grant including the transmission instruction transmitted in advance, the UL scheduling grant transmitted next is changed to the UL scheduling grant including the SRS transmission instruction. Selected. Note that the UL scheduling grant selection method including the SRS transmission instruction can be changed as appropriate. The same applies to the reference signal transmission methods according to the second and third aspects described later.

  In the reference signal transmission method according to the second aspect of the present invention, in the base station apparatus eNodeB, a UL scheduling grant that assigns “1” indicating transmission on to the transmission identification bit is selected, and the SRS of the SRS is selected by the selected UL scheduling grant. The mobile station apparatus UE is instructed to transmit or not, and the mobile station apparatus UE transmits the SRS in a subframe immediately before the PUSCH subframe in which transmission is instructed by the UL scheduling grant including the transmission identification bit.

  FIG. 3 is a diagram for explaining SRS transmitted by the reference signal transmission method according to the second aspect. FIG. 3 shows a case where the UL scheduling grant of subframes #m and # m + 4 is selected as the UL scheduling grant including an SRS transmission instruction in base station apparatus eNodeB, as in FIG. When receiving the notification of the UL scheduling grant including the SRS transmission instruction, the mobile station apparatus UE receives subframes # n + 3 and # n + 7 immediately before the subframes # n + 4 and # n + 8 that transmit PUSCH according to the UL scheduling grant. The SRS is transmitted to the base station apparatus eNodeB.

  In the reference signal transmission method according to the second aspect, since the SRS is transmitted in a subframe immediately before the PUSCH subframe in which transmission is instructed by the UL scheduling grant including the transmission instruction, subframes # n + 3, # It is multiplexed on the final symbol of n + 7. That is, the SRS is continuously multiplexed before the PUSCH assigned to the subframes # n + 4 and # n + 8. In the base station apparatus eNodeB, the channel quality is measured based on the SRS continuously multiplexed on the PUSCH in this way, and scheduling for PUSCH transmission in the mobile station apparatus UE is performed. For this reason, since the channel quality at the timing when the PUSCH is actually transmitted can be measured, it is possible to perform scheduling reflecting the channel state.

  In the reference signal transmission method according to the third aspect of the present invention, in the base station apparatus eNodeB, a UL scheduling grant that assigns “1” indicating transmission on to the transmission identification bit is selected, and the SRS of the SRS is selected by the selected UL scheduling grant. The mobile station apparatus UE is instructed whether or not to transmit, and the mobile station apparatus UE transmits SRS in a subframe that is a predetermined number of PUSCH subframes at which transmission is instructed by the UL scheduling grant including this transmission identification bit. To do.

  FIG. 4 is a diagram for explaining SRS transmitted by the reference signal transmission method according to the third aspect. In FIG. 4, as in FIGS. 2 and 3, in the base station apparatus eNodeB, the case where the UL scheduling grant of subframes #m and # m + 4 is selected as the UL scheduling grant including the SRS transmission instruction is shown. Yes. When receiving the notification of the UL scheduling grant including the SRS transmission instruction, the mobile station apparatus UE transmits a predetermined number of subframes # n + 4 and # n + 8 (here, three subframes) that transmit PUSCH according to the UL scheduling grant. ) In the previous subframes # n + 1 and # n + 5, the SRS is transmitted to the base station apparatus eNodeB.

  In the reference signal transmission method according to the third aspect, since the SRS is transmitted in a subframe three subframes before the PUSCH subframe in which transmission is instructed by the UL scheduling grant including the transmission instruction, the subframe # It is multiplexed on the final symbols of n + 1 and # n + 5. That is, SRS is multiplexed prior to PUSCH allocated to subframes # n + 4 and # n + 8. In the base station apparatus eNodeB, the channel quality is measured based on the SRS multiplexed prior to the PUSCH in this way, and scheduling for PUSCH transmission in the mobile station apparatus UE is performed. Therefore, the channel quality can be measured at a timing approximate to the timing at which the PUSCH is actually transmitted, and the scheduling content can be reflected in the UL scheduling grant including the subsequent transmission instruction.

  Referring to the specific example shown in FIG. 4, in the base station apparatus eNodeB, the channel quality is measured based on the SRS transmitted from the mobile station apparatus UE and multiplexed in the last symbol of subframe # n + 1. Based on the measurement result of the channel quality, scheduling for PUSCH transmission in the mobile station apparatus UE is performed. Here, since scheduling can be performed prior to subframe # m + 4 to which a UL scheduling grant including an SRS transmission instruction is assigned next, the contents of this scheduling are reflected in the UL scheduling grant of subframe # m + 4. Can do.

  In the reference signal transmission method according to the third aspect, mobile station apparatus UE transmits SRS in a subframe that is a predetermined number of PUSCH subframes at which transmission is instructed by a UL scheduling grant including a transmission instruction. However, it is also possible to transmit the SRS in a subframe after a predetermined number of PUSCH subframes to be transmitted with a UL scheduling grant including a transmission instruction. In this way, by adjusting the SRS transmission timing, it is possible to adjust inter-user interference. In the reference signal transmission method according to the third aspect, the SRS is transmitted in a subframe before or after a predetermined number of PUSCH subframes to be transmitted by the UL scheduling grant.

  In the reference signal transmission method according to the fourth aspect of the present invention, in the base station apparatus eNodeB, a UL scheduling grant that assigns “1” indicating transmission on to the transmission identification bit is selected, and the SRS of the SRS is selected by the selected UL scheduling grant. Instructing the presence or absence of transmission to the mobile station apparatus UE, in the mobile station apparatus UE, with reference to a subframe that is a predetermined number of subframes of PUSCH instructed to be transmitted with the UL scheduling grant including this transmission identification bit, SRS is transmitted in a subframe in which SRS transmission is earliest from the reference subframe.

  FIG. 5 is a diagram for explaining SRS transmitted by the reference signal transmission method according to the fourth aspect. FIG. 5 shows the case where the UL scheduling grant of subframes #m and # m + 4 is selected as the UL scheduling grant including the SRS transmission instruction in the base station apparatus eNodeB, as in FIGS. Yes. Further, the uplink has limited subframes (# n + 1, # n + 4, # n + 7) that can transmit SRS. Since subframes used for transmission of broadcast information and RRC control information are limited in SRS transmission, subframes in which SRS can be transmitted are limited in advance. In the example shown in FIG. 5, a UL scheduling grant including an SRS transmission instruction is received in downlink subframe #m, and PUSCH is transmitted in subframe # n + 4 after four subframes. The subframe # n + 1 that is returned by x subframes (x = 3 in the figure) from the subframe # n + 4 that transmits the PUSCH is used as a reference, and the earliest SRS transmission is possible including the reference subframe # n + 1. SRS is transmitted in a subframe. In the example shown in FIG. 5, the reference subframe # n + 1 is the earliest SRS-transmittable subframe. Also, a UL scheduling grant including an SRS transmission instruction is received in downlink subframe # m + 4, and PUSCH is transmitted in subframe # n + 8 after four subframes are received. Based on subframe # n + 5 returned three subframes before subframe # n + 8 for transmitting such PUSCH, SRS is transmitted in the earliest subframe capable of SRS transmission including subframe # n + 5 of the reference. In the example illustrated in FIG. 5, the reference subframe # n + 5 is not a subframe in which SRS can be transmitted. Since the earliest subframe capable of SRS transmission from the reference subframe # n + 5 is subframe # n + 7, SRS is transmitted in subframe # n + 7.

  In this way, if a rule such that SRS is transmitted in a subframe in which SRS can be transmitted earliest from the reference subframe is applied, broadcast information in a subframe returned by a predetermined number of subframes from a subframe in which PUSCH is transmitted, Even if RRC control information is transmitted, collision with the SRS can be avoided.

  In the reference signal transmission methods according to the first to fourth aspects, the subframe in which the SRS is transmitted is specified according to the UL scheduling grant including the SRS transmission instruction (for example, according to the first aspect) (Subframe after 4 subframes in the reference signal transmission method). In this case, as a method for specifying the subframe in which the SRS is transmitted, the specific content of the subframe may be included in the UL scheduling grant, or the specific content of the subframe is determined by the specification in the mobile station apparatus UE. Alternatively, the specification may be specified according to the reception of the UL scheduling grant. When the subframe in which the SRS is transmitted is specified according to the specific content included in the UL scheduling grant, the reference signal transmission methods according to the first to fourth aspects can be switched and applied.

  By the way, in the LTE system, resource information (hereinafter referred to as “SRS multiplexing information”) for multiplexing SRSs from a plurality of mobile station apparatuses UE in the same symbol is transmitted to each mobile station apparatus UE by RRC signaling. Notify. The SRS multiplexing information includes, for example, position information (Comb: 1 bit) indicating whether the subframe in which the SRS is multiplexed is odd or even, and a shift assigned to each mobile station apparatus UE when the SRS is code multiplexed. The amount (cyclic shift: 3 bits), the bandwidth (Bandwidth: 2 bits) to be multiplexed with the SRS, and the frequency position (Frequency position: undefined bits) with which the SRS is multiplexed are included.

  In the reference signal transmission method according to the present invention that dynamically controls the transmission timing of SRS, it is preferable to notify such SRS multiplexing information using UL scheduling grant (PDCCH). However, when all the SRS multiplexing information is included in the UL scheduling grant and notified, the amount of information allocated to the UL scheduling grant increases, and the efficiency such as generation of the UL scheduling grant in the base station apparatus eNodeB may deteriorate. Conceivable. For this reason, in the reference signal transmission method according to the present invention, SRS multiplexing information is reported using both higher layer signaling (RRC signaling) and UL scheduling grant (PDCCH).

  For example, in the reference signal transmission method according to the present invention, the position information (Comb: 1 bit) of the subframe in which SRS is multiplexed and the bandwidth (Bandwidth: 2 bits) to be multiplexed are reported by RRC signaling. On the other hand, the shift amount (cyclic Shift: 3 bits) allocated to each mobile station apparatus UE and the frequency position (Frequency position: indefinite bits) for multiplexing SRS are reported by UL scheduling grant (PDCCH). In this case, the SRS multiplexing information included in the UL scheduling grant (PDCCH) can be notified to the mobile station apparatus UE earlier than the SRS multiplexing information included in the RRC signaling, and the SRS multiplexing information is used. It is possible to quickly perform control to be performed by the mobile station apparatus UE. The information for SRS multiplexing assigned to RRC signaling and UL scheduling grant (PDCCH) is not particularly limited and can be changed as appropriate.

  In addition, when higher layer signaling and PDCCH are used together to notify SRS multiplexing information, it is desirable to notify SRS multiplexing information to be transmitted on PDCCH using other control bits in PDCCH. The forms using other control bits include both overwriting the SRS multiplexing information on other control bits and using the other control bits as they are as SRS multiplexing information. For example, the bandwidth (Bandwidth: 2 bits) and the frequency position (Frequency position: indefinite bit) are notified using RRC signaling, and the SRS transmission instruction and subframe position information (Comb: 1) are used using PDCCH. (Bit) and shift amount (cyclic Shift: 3 bits) will be described as an example. The SRS transmission instruction uses 1 bit secured in the PDCCH. Subframe position information (Comb: 1 bit) and shift amount (cyclic Shift: 3 bits), which are the remaining resource information, are overwritten on other control bits. Alternatively, other control bits are used as they are.

  FIG. 6 shows the format structure (DCI format 0) of the UL scheduling grant sent on the PDCCH. 6A shows the format when the SRS transmission instruction is OFF, and FIG. 6B shows the format when the SRS transmission instruction is ON. As shown in FIG. 6A, DCI format 0 is a flag whose first 1 bit identifies DCI Format 1 or DCI Format 0. The second bit is a control bit indicating presence / absence of frequency hopping in the uplink control channel. The 3rd to 9th bits are control bits of resource block allocation information indicating the resource block position allocated to the user. Thereafter, MCS information of the allocated resource block and redundant version (RV) control bits are arranged, and an identifier (New data indicator) for discriminating between new data and retransmission data is arranged by 1 bit. Furthermore, a PUSCH transmission power control command (TPC), a control bit for cyclic shift (CS for DMRS) of a demodulation reference signal, and a CQI request are arranged. Two bits are added as padding bits following the CQI request. The first padding bit is used for an SRS transmission instruction. If this control bit is “0”, SRS transmission is OFF, and if “1”, SRS transmission is ON. As shown in FIG. 6B, when the SRS transmission instruction is ON, “1” is set to the first bit of the padding bits. The subframe position information (Comb: 1 bit) overwrites the control bit (second bit) indicating the presence or absence of frequency hopping. As the shift amount (cyclic shift: 3 bits), the control bits of the cyclic shift (CS for DMRS) of the demodulation reference signal having the same number of bits as the shift amount are used as they are. In other words, the shift amount for SRS multiplexing and the cyclic shift (CS for DMRS) of the reference signal for demodulation are linked so that they have the same bit value. As described above, the SRS multiplexing information to be transmitted on the PDCCH is notified by using other control bits on the PDCCH, so that the number of bits of the UL scheduling grant (DCI format 0) can be prevented from increasing.

Moreover, in the reference signal transmission method according to the first to fourth aspects, the SRS is multiplexed on the final symbol of a specific subframe according to the UL scheduling grant notified from the base station apparatus eNodeB. For example, as shown in FIG. 7, the SRS is multiplexed on the last symbol of the corresponding subframe. The PUSCH is multiplexed on the resource block (N _RB ) assigned to the mobile station apparatus UE. DMRS (Demodulation Reference Signal) is multiplexed on the third symbol of each slot in the resource block (N _RB ) allocated to the mobile station apparatus UE. In addition, in FIG. 7, it has shown about the sub-frame with which SRS was multiplexed in the reference signal transmission method which concerns on a 1st aspect. Here, the reference signal transmission method according to the first aspect is described as an example, but the same applies to the reference signal transmission methods according to the second, third, and fourth aspects.

  However, in the reference signal transmission methods according to the first to fourth aspects, since symbols that can be multiplexed with SRS are limited to the final symbols of the subframe, for example, the end of the cell where the mobile station apparatus UE is located When located in a part, there may occur a situation in which the transmission power is insufficient and the base station apparatus eNodeB cannot properly receive the SRS. In order to cope with such a situation, in the reference signal transmission methods according to the fifth to eighth aspects of the present invention, the SRS is multiplexed on a plurality of symbols different from the final symbol.

  In the reference signal transmission method according to the fifth aspect of the present invention, the SRS is multiplexed on the DMRS of the corresponding subframe. FIG. 8 is a diagram for explaining symbols on which SRSs are multiplexed in the reference signal transmission method according to the fifth aspect of the present invention. As shown in FIG. 8, in the fifth reference signal transmission method, SRS is multiplexed on the third symbol of each slot constituting the corresponding subframe, and transmitted to the base station apparatus eNodeB simultaneously with DMRS. Note that multiplexing of SRS superimposed on DMRS can be realized using, for example, a code orthogonal to DMRS.

  Thus, in the reference signal transmission method according to the fifth aspect, a plurality (two) of SRSs are multiplexed and transmitted in the subframe specified by the UL scheduling grant including the SRS transmission instruction. Compared with the case where the SRS is multiplexed only on the final symbol, the base station apparatus eNodeB can easily receive the SRS appropriately.

  In the reference signal transmission method according to the sixth aspect of the present invention, the SRS is multiplexed on the PUSCH of the corresponding subframe. FIG. 9 is a diagram for explaining symbols on which SRSs are multiplexed in the reference signal transmission method according to the sixth aspect of the present invention. As shown in FIG. 9, in the sixth reference signal transmission method, SRSs are multiplexed on all symbols except the third symbol in each slot constituting the corresponding subframe and the final symbol of the corresponding subframe. And transmitted to the base station apparatus eNodeB simultaneously with the PUSCH. In this case, it is preferable to transmit SRS with small transmission power compared with PUSCH.

  As described above, in the reference signal transmission method according to the sixth aspect, a plurality (11) of SRSs are multiplexed and transmitted in the subframe specified by the UL scheduling grant including the SRS transmission instruction. Compared with the case where the SRS is multiplexed only on the final symbol, the base station apparatus eNodeB can easily receive the SRS appropriately. Also, since SRS is multiplexed and multiplexed on PUSCH, it is possible to make it difficult to affect the channel quality measurement accuracy in base station apparatus eNodeB compared to the case of multiplexing and multiplexing on DMRS.

  In the reference signal transmission method according to the seventh aspect of the present invention, the SRS is multiplexed on the DMRS and PUSCH of the corresponding subframe. That is, it corresponds to a reference signal transmission method in which the reference signal transmission method according to the fifth aspect and the reference signal transmission method according to the sixth aspect are combined. FIG. 10 is a diagram for explaining symbols on which SRSs are multiplexed in the reference signal transmission method according to the seventh aspect of the present invention. As shown in FIG. 10, in the seventh reference signal transmission method, SRSs are multiplexed on all symbols except the final symbol of the corresponding subframe, and transmitted to the base station apparatus eNodeB simultaneously with PUSCH and DMRS.

  As described above, in the reference signal transmission method according to the seventh aspect, a plurality (13) of SRSs are multiplexed and transmitted in the subframe specified by the UL scheduling grant including the SRS transmission instruction. Compared with the case where the SRS is multiplexed only on the final symbol, the base station apparatus eNodeB can easily receive the SRS appropriately. In particular, since the SRS is multiplexed on all symbols except the final symbol of the subframe, the SRS can be more easily received by the base station apparatus eNodeB than when multiplexed only on the PUSCH or only on the DMRS. Is possible.

In the reference signal transmission method according to the eighth aspect of the present invention, the SRS is multiplexed in a resource block different from the resource block allocated to the mobile station apparatus UE in the corresponding subframe. FIG. 11 is a diagram for explaining symbols on which SRSs are multiplexed in the reference signal transmission method according to the eighth aspect of the present invention. As illustrated in FIG. 11, in the eighth reference signal transmission method, the final symbol of the subframe is selected from among the resource blocks (N _RB ′) different from the resource blocks (N _RB ) allocated to the mobile station apparatus UE. SRS is multiplexed on all the symbols except for, and transmitted to the base station apparatus eNodeB simultaneously with PUSCH and DMRS.

As described above, in the reference signal transmission method according to the eighth aspect, a plurality (13) of SRSs are multiplexed and transmitted in the subframe specified by the UL scheduling grant including the SRS transmission instruction. Compared with the case where the SRS is multiplexed only on the final symbol, the base station apparatus eNodeB can easily receive the SRS appropriately. In addition, since SRS is multiplexed in a resource block (N _RB ′) different from the resource block (N _RB ) allocated to the mobile station apparatus UE, interference with PUSCH is reduced compared to the case of being multiplexed over PUSCH. It becomes possible to suppress.

  In addition, when the symbol which multiplexes SRS like this is selected dynamically, the symbol which multiplexes SRS can also be selected from a viewpoint of the demodulation precision of the data channel signal (PUSCH) in base station apparatus eNodeB. In general, in a data channel signal, the demodulation accuracy of an end symbol in a subframe tends to deteriorate. For this reason, it is preferable as an embodiment to multiplex SRS unrelated to the data channel signal on the symbol whose demodulation accuracy deteriorates in this way. Hereinafter, an aspect of multiplexing SRS in this way will be described.

In the reference signal transmission method according to the ninth aspect of the present invention, SRS is multiplexed on the head symbol of PUSCH in the corresponding subframe. FIG. 17 is a diagram for explaining symbols in which SRSs are multiplexed in the reference signal transmission method according to the ninth aspect of the present invention. As shown in FIG. 17, in the ninth reference signal transmission method, SRS is multiplexed on the resource block (N _RB ) allocated to the mobile station apparatus UE among the head symbols (0th symbol) of the corresponding subframe. And transmitted to the base station apparatus eNodeB simultaneously with the PUSCH.

  Thus, in the reference signal transmission method according to the ninth aspect, the SRS is multiplexed and transmitted on the first symbol of the PUSCH among the subframes specified by the UL scheduling grant including the SRS transmission instruction. When transmitting a data channel signal (PUSCH) in this way, SRS is multiplexed on a symbol whose demodulation accuracy can be degraded, so radio resources can be efficiently used while suppressing degradation of the demodulation accuracy of the data channel signal. Can be used for

In the reference signal transmission method according to the tenth aspect of the present invention, the SRS is multiplexed on the top symbol of the PUSCH in the corresponding subframe. FIG. 18 is a diagram for explaining symbols on which SRSs are multiplexed in the reference signal transmission method according to the tenth aspect of the present invention. As shown in FIG. 18, in the tenth reference signal transmission method, a wideband including a resource block (N _RB ) allocated to the mobile station apparatus UE among the head symbols (0th symbol) of the corresponding subframe. The SRS is multiplexed on the resource block (N _{RB ″} ) and transmitted to the base station apparatus eNodeB simultaneously with the PUSCH.

As described above, in the reference signal transmission method according to the tenth aspect, the SRS is multiplexed and transmitted on the first symbol of the PUSCH among the subframes specified by the UL scheduling grant including the SRS transmission instruction. When transmitting a data channel signal (PUSCH) in this way, as in the reference signal transmission method according to the ninth aspect, radio resources are efficiently used while suppressing deterioration in demodulation accuracy of the data channel signal. can do. In the reference signal transmission method according to a tenth aspect, based on the multiplexed to the mobile station apparatus UE allocated resource blocks (N _RB) broadband resource blocks including (N _RB'') SRS channel Since the quality can be measured, it is possible to improve the measurement accuracy of the channel quality.

  In the reference signal transmission methods according to the first to tenth aspects described above, the SRS is transmitted from the mobile station apparatus UE in response to the SRS transmission instruction included in the UL scheduling grant. However, as described in the eleventh reference signal transmission method, the SRS may be transmitted from the mobile station apparatus UE in response to an SRS transmission instruction included in a scheduling grant other than the UL scheduling grant.

  In the reference signal transmission method according to the eleventh aspect, an SRS scheduling grant is provided, and an SRS is transmitted from the mobile station apparatus UE in response to an SRS transmission instruction included in the SRS scheduling grant.

  FIG. 19 is a diagram for explaining a format configuration of an SRS scheduling grant (also referred to as an Aperiodic SRS grant) used in the reference signal transmission method according to the eleventh aspect of the present invention. FIG. 19A shows the format configuration of the UL scheduling grant, and FIG. 19B shows the format configuration of the scheduling grant for SRS. The UL scheduling grant in FIG. 19A has the same configuration as the UL scheduling grant when the SRS transmission instruction shown in FIG. 6A is OFF. The scheduling grant for SRS shown in FIG. 19B notifies the mobile station apparatus UE of scheduling information for transmitting SRS, as will be described in detail below.

  As shown in FIG. 19B, TxBW (TxBandwidth) of the first and second bits of the scheduling grant for SRS is the transmission bandwidth of SRS. The frequency position from the third bit to the seventh bit is a frequency position at which the SRS is transmitted. The eighth bit Comb is position information of a subframe in which the SRS is transmitted. The ninth to eleventh bit CS (Cyclic shift) is the shift amount of the SRS cyclic shift. The 12th to 13th bits of Hopping BW (Bandwith) is a frequency hopping band. The Duration of the 14th to 15th bits is the SRS transmission period. In the reference information transmission methods according to the first to tenth aspects, the resource information for transmitting the SRS as described above is reported in principle by RRC signaling due to the restriction on the information amount of the UL scheduling grant. In the reference information transmission method according to the eleventh aspect, since a scheduling grant for SRS is provided, resource information for transmitting SRS can be notified to mobile station apparatus UE by PDCCH.

  As shown in FIG. 19B, the SRS scheduling grant includes transmission control information (for example, extended transmission power control information (Extended) described later) for controlling transmission of not only the SRS but also the data channel signal (PUSCH). TPC) and transmission timing control information (TA). Note that the scheduling grant for SRS may include either or both of extended transmission power control information (Extended TPC) and transmission timing control information (TA), which will be described later.

  The extended TPC of the 16th to 19th bits in FIG. 19B is extended transmission power control information for controlling the transmission power of the SRS or / and data channel signal (PUSCH) in the extended control range. FIG. 20 is a diagram for explaining extended transmission power control information (Extended TPC). Fig.20 (a) shows the content of the transmission power control information (TPC) contained in UL scheduling grant of Fig.19 (a). 2-bit transmission power control information (TPC) increases or decreases transmission power in four stages. On the other hand, FIG. 20B shows the contents of the extended transmission power control information (Extended TPC) included in the SRS scheduling grant in FIG. 19B. The 4-bit extended transmission power control information (Extended TPC) increases or decreases the transmission power in 16 steps. According to the extended transmission power control information (Extended TPC), since the number of bits is extended from 2 bits to 4 bits, the SRS or / and the data channel signal (PUSCH) in a control range larger than the transmission power control information (TPC). ) Transmission power can be controlled. The extended transmission power control information (Extended TPC) is not limited to 4 bits, and may be 3 bits or 5 bits or more.

  TA (Timing Advance) of the 20th to 23rd bits in FIG. 19B is transmission timing control information for controlling the transmission timing of the SRS and / or the data channel signal (PUSCH). Note that the transmission timing control information (TA) is normally included in the RACH Response transmitted from the base station apparatus eNodeB during the initial access of the mobile station apparatus UE. Such transmission timing control information (TA) is also notified to the mobile station apparatus UE by an SRS scheduling grant, so that the mobile station apparatus UE prevents an error in transmission timing control caused by the passage of time from the initial access. it can.

  The 24th bit of FIG.19 (b) is a control bit used for the transmission instruction | indication of SRS. In the scheduling grant for SRS, “1” indicating that transmission of SRS is requested is set.

  As described above, the SRS scheduling grant shown in FIG. 19B includes transmission control information for controlling transmission of not only the SRS but also the data channel signal (PUSCH) in addition to the resource information for transmitting the SRS. Can be included. According to such a scheduling grant for SRS, even when the mobile station apparatus UE resumes transmission after interrupting transmission of the data channel signal (PUSCH), the transmission power and transmission timing of the data channel signal (PUSCH) are appropriately set. Can be set. With reference to FIG. 21, the transmission power control and transmission timing control of the data channel signal (PUSCH) using the scheduling grant for SRS in the mobile station apparatus UE will be described in detail.

  FIG. 21 illustrates transmission power control and transmission timing control of a data channel signal (PUSCH) using an SRS scheduling grant (also referred to as an Aperiodic SRS grant) transmitted by the reference signal transmission method according to the eleventh aspect. FIG. As shown in FIG. 21, when there is a data channel signal (PUSCH) transmitted from the mobile station apparatus UE in the uplink, the UL scheduling grant is transmitted from the base station apparatus eNodeB in the downlink. The mobile station apparatus UE controls the transmission power of the data channel signal (PUSCH) in the uplink according to the transmission power information (TPC) included in the UL scheduling grant. In FIG. 21, the UL scheduling grant is transmitted to the mobile station apparatus UE in downlink subframes #m to # m + 2. The mobile station apparatus UE controls the transmission power of the data channel signal (PUSCH) transmitted in subframes #n to # n + 2 according to the transmission power information (TPC) included in the UL scheduling grant. On the other hand, when transmission of the data channel signal (PUSCH) transmitted from the mobile station apparatus UE in the uplink is resumed, the transmission power and transmission timing of the data channel signal (PUSCH) are appropriately set. There are cases where it is not possible.

  Therefore, as illustrated in FIG. 21, when the mobile station apparatus UE intends to resume transmission of the data channel signal (PUSCH), the base station apparatus eNodeB responds to a Scheduling Request (not shown) received from the mobile station apparatus UE. Then, the SRS scheduling grant is transmitted to the mobile station apparatus UE. The mobile station apparatus UE controls the transmission power and transmission timing of the uplink data channel signal (PUSCH) according to extended transmission control information (Extended TPC) and transmission timing information (TA) included in the SRS scheduling grant. In FIG. 21, a scheduling grant for SRS is transmitted to mobile station apparatus UE in downlink subframe # m + s. The mobile station apparatus UE transmits a data channel signal (PUSCH) whose transmission is resumed in subframe # n + s + 3 according to the extended transmission power control information (Extended TPC) and transmission timing information (TA) included in the scheduling grant for SRS. Control transmission power and transmission timing. Here, the extended transmission control information (Extended TPC) and the transmission timing information (TA) are set to appropriate values by the SRS transmitted periodically or in response to the transmission instruction even after the transmission interruption of the data channel signal (PUSCH). Is set. Furthermore, the extended transmission control information (Extended TPC) has an extended transmission power control range. Therefore, as shown in FIG. 21, even when the mobile station apparatus UE intends to resume after suspending the data channel signal (PUSCH) transmission, the mobile station apparatus UE sets transmission power and transmission timing appropriately. can do. The mobile station apparatus UE transmits the SRS in the uplink subframe # n + s because the SRS transmission grant is included in the SRS scheduling grant transmitted in the downlink subframe # m + s.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Here, a case where a base station apparatus and a mobile station apparatus corresponding to an LTE-A system (LTE-A system) are used will be described.

  A mobile communication system 1 having a mobile station apparatus (UE) 10 and a base station apparatus (eNodeB) 20 according to an embodiment of the present invention will be described with reference to FIG. FIG. 12 is a diagram for explaining the configuration of the mobile communication system 1 including the mobile station apparatus 10 and the base station apparatus 20 according to an embodiment of the present invention. Note that the mobile communication system 1 illustrated in FIG. 12 is a system including, for example, an LTE system or SUPER 3G. Moreover, this mobile communication system 1 may be called IMT-Advanced, and may be called 4G.

As illustrated in FIG. 12, the mobile communication system 1 includes a base station device 20 and a plurality of mobile station devices 10 (10 ₁ , 10 ₂ , 10 ₃ ,... 10 _n , n communicating with the base station device 20. Is an integer of n> 0). The base station apparatus 20 is connected to the higher station apparatus 30, and the higher station apparatus 30 is connected to the core network 40. The mobile station device 10 communicates with the base station device 20 in the cell 50. The upper station device 30 includes, for example, an access gateway device, a radio network controller (RNC), a mobility management entity (MME), and the like, but is not limited thereto.

Since each mobile station apparatus (10 ₁ , 10 ₂ , 10 ₃ ,... 10 _n ) has the same configuration, function, and state, the following description will be given as the mobile station apparatus 10 unless otherwise noted. Proceed. For convenience of explanation, it is assumed that the mobile station device 10 is in radio communication with the base station device 20, but more generally user equipment (UE: User Equipment) including both the mobile station device and the fixed terminal device. It's okay.

  In the mobile communication system 1, as a radio access scheme, OFDMA (orthogonal frequency division multiple access) is used for the downlink, and SC-FDMA (single carrier-frequency division multiple access) or clustered DFT spread OFDM (Clustered) is used for the uplink. DFT-Spread OFDM) is applied. OFDMA is a multi-carrier transmission scheme that performs communication by dividing a frequency band into a plurality of narrow frequency bands (subcarriers) and mapping data to each subcarrier. SC-FDMA is a single carrier transmission scheme that reduces interference between terminals by dividing a system band into bands each consisting of one or continuous resource blocks for each terminal, and a plurality of terminals using different bands. . Clustered DFT-spread OFDM assigns non-contiguous clustered subcarrier groups (clusters) to one mobile station UE and applies discrete Fourier transform spread OFDM to each cluster, thereby increasing uplink multiples. This is a method for realizing connection.

  Here, a communication channel in the LTE system will be described. For downlink, PDSCH shared by each mobile station device 10 and downlink L1 / L2 control channels (PDCCH, PCFICH, PHICH) are used. User data, that is, a normal data signal is transmitted by this PDSCH. Transmission data is included in this user data. Note that the UL scheduling grant including the transmission identification bit described above is notified to the mobile station apparatus 10 through the L1 / L2 control channel (PDCCH).

  For the uplink, PUSCH that is shared and used by each mobile station apparatus 10 and PUCCH that is an uplink control channel are used. User data is transmitted by this PUSCH. Also, downlink radio quality information (CQI: Channel Quality Indicator) and the like are transmitted by PUCCH.

  The overall configuration of mobile station apparatus 10 according to the present embodiment will be described with reference to FIG. Since the main parts of the hardware of the LTE terminal and the LTE-A terminal are the same, they will be described without distinction. The mobile station device 10 includes a transmission / reception antenna 11, an amplifier unit 12, a transmission / reception unit 13, a baseband signal processing unit 14, and an application unit 15. The transmission / reception antenna 11, the amplifier unit 12, the transmission / reception unit 13, and a part of the baseband signal processing unit 14 constitute reception means.

  For downlink data, a radio frequency signal received by the transmission / reception antenna 11 is amplified by the amplifier unit 12, frequency-converted by the transmission / reception unit 13, and converted into a baseband signal. The baseband signal is subjected to FFT processing, error correction decoding, retransmission control reception processing, and the like by the baseband signal processing unit 14. Among the downlink data, downlink user data is transferred to the application unit 15. The application unit 15 performs processing related to a higher layer than the physical layer and the MAC layer. In addition, broadcast information in the downlink data is also transferred to the application unit 15.

  On the other hand, uplink user data is input from the application unit 15 to the baseband signal processing unit 14. In the baseband signal processing unit 14, transmission processing of retransmission control (H-ARQ (Hybrid ARQ)), channel coding, DFT processing, IFFT processing, and the like are performed and transferred to the transmission / reception unit 13. In the transmission / reception unit 13, frequency conversion processing for converting the baseband signal output from the baseband signal processing unit 14 into a radio frequency band is performed, and then amplified by the amplifier unit 12 and transmitted from the transmission / reception antenna 11.

  Next, the overall configuration of base station apparatus 20 according to the present embodiment will be described with reference to FIG. The base station apparatus 20 includes a transmission / reception antenna 21, an amplifier unit 22, a transmission / reception unit 23, a baseband signal processing unit 24, a call processing unit 25, and a transmission path interface 26. The transmission / reception antenna 21, the amplifier unit 22, the transmission / reception unit 23, and a part of the baseband signal processing unit 24 constitute transmission means.

  User data transmitted from the base station apparatus 20 to the mobile station apparatus 10 via the downlink is input to the baseband signal processing unit 24 from the upper station apparatus 30 positioned above the base station apparatus 20 via the transmission path interface 26. The

  In the baseband signal processing unit 24, PDCP layer processing, user data division / combination, RLC layer transmission processing such as RLC (radio link control) retransmission control transmission processing, MAC (Medium Access Control) retransmission control, for example, HARQ (Hybrid Automatic Repeat reQuest) transmission processing, scheduling, transmission format selection, channel coding, inverse fast Fourier transform (IFFT) processing, and precoding processing are performed. Also, transmission processing such as channel coding and inverse fast Fourier transform is performed on the signal of the physical downlink control channel, which is the downlink control channel, and is transferred to the transmission / reception unit 23.

  In the transmission / reception unit 23, frequency conversion processing for converting the baseband signal output from the baseband signal processing unit 24 into a radio frequency band is performed, and then amplified by the amplifier unit 22 and transmitted from the transmission / reception antenna 21.

  On the other hand, for the signal transmitted from the mobile station apparatus 10 to the base station apparatus 20 via the uplink, the radio frequency signal received by the transmission / reception antenna 21 is amplified by the amplifier unit 22. The frequency is converted by the transmission / reception unit 23 to be converted into a baseband signal, and then input to the baseband signal processing unit 24.

  The baseband signal processing unit 24 performs FFT processing, IDFT processing, error correction decoding, MAC retransmission control reception processing, RLC layer, PDCP layer reception processing on user data included in the input baseband signal. Then, the data is transferred to the higher station apparatus 30 via the transmission path interface 206.

  The call processing unit 25 performs call processing such as communication channel setting and release, state management of the base station apparatus 20, and radio resource management.

  FIG. 15 is a functional block diagram of baseband signal processing section 14 included in mobile station apparatus 10 according to the present embodiment. 15 shows only the configuration related to the reference signal transmission method according to the present invention for the sake of convenience of explanation, the baseband signal processing unit 14 shown in FIG. 15 has a configuration included in a normal baseband processing unit. It shall be. In the following, SRS whose transmission timing is dynamically controlled by the reference signal transmission method according to the present invention is referred to as “Dynamic SRS”, and is periodically transmitted without being dynamically controlled. That is, SRS in the LTE system is referred to as “Semi-static SRS”.

  The uplink scheduling grant transmitted from the base station apparatus 20 in the downlink is input to the scheduling grant demodulation / decoding unit 140 to be demodulated and decoded. Then, the demodulation and decoding results of the uplink scheduling grant are output to a data channel signal generation unit 146 and a PUSCH mapping unit 148 described later. The UL scheduling grant includes uplink resource block allocation information, mobile station device 10 ID, data size, modulation scheme, uplink transmission power information, and DMRS information. In the reference signal transmission method according to the fourth aspect of the present invention, the UL scheduling grant with the format shown in FIG. 6 (a) or (b) is decoded. At this time, interpretation of some control bits is switched depending on whether the SRS transmission instruction is “0” (OFF) or “1” (ON). When the SRS transmission instruction is “0” (OFF), the control bit is recognized with the same interpretation as LTE. On the other hand, when the transmission instruction of SRS is “1” (ON), the control bit indicating the shift amount of DMRS in LTE is interpreted as a control bit indicating the shift amount of SRS (cyclic shift: 3 bits).

  If the UL scheduling grant includes a Dynamic SRS transmission instruction as a result of demodulation and decoding of the UL scheduling grant, the Dynamic SRS signal generation unit 141 is notified of this. In addition, the presence or absence of the transmission instruction | indication of Dynamic SRS in UL scheduling grant is judged by the presence or absence of the transmission identification bit mentioned above. Further, when SRS multiplexing information is included in the UL scheduling grant, this SRS multiplexing information is output to the Dynamic SRS mapping unit 142. When SRS multiplexing information is notified by RRC signaling, this SRS multiplexing information is also output to the Dynamic SRS mapping unit 142. In the reference signal transmission method according to the fourth aspect of the present invention, subframe information capable of transmitting SRS is RRC-signaled in advance and provided to Dynamic SRS mapping section 142.

  On the other hand, when receiving an UL scheduling grant that does not include a Dynamic SRS transmission instruction, that is, an UL scheduling grant in the LTE system, the fact is notified to the Semi-static SRS signal generation unit 143. Further, when the SRS multiplexing information is notified by RRC signaling, this SRS multiplexing information is output to the Semi-static SRS mapping unit 144.

  The Dynamic SRS signal generation unit 141 generates a Dynamic SRS according to a transmission instruction included in the UL scheduling grant. The Dynamic SRS mapping unit 142 maps the Dynamic SRS generated by the Dynamic SRS signal generation unit 141 to the radio resource based on the SRS multiplexing information notified by the UL scheduling grant or the SRS multiplexing information notified by RRC signaling. To do. This Dynamic SRS mapping unit 142 constitutes a multiplexing means. Dynamic SRS is multiplexed on a predetermined symbol by being mapped to a radio resource by the Dynamic SRS mapping unit 142. Then, the Dynamic SRS mapped to the radio resource is output to the inverse fast Fourier transform unit (IFFT) 145.

  For example, when the Dynamic SRS is generated according to the reference signal transmission method according to the first aspect, the Dynamic SRS is multiplexed on the last symbol of the same subframe as the PUSCH in which transmission is instructed by the UL scheduling grant including the transmission instruction. Is done. Also, when the Dynamic SRS is generated according to the reference signal transmission method according to the second aspect, Dynamic is added to the final symbol of the subframe immediately before the PUSCH subframe in which transmission is instructed by the UL scheduling grant including the transmission instruction. SRS is multiplexed. Further, when the dynamic SRS is generated according to the reference signal transmission method according to the third aspect, the last of the subframes preceding by a predetermined number of PUSCH subframes to be transmitted by the UL scheduling grant including the transmission instruction Dynamic SRS is multiplexed on the symbol. Also, when the dynamic SRS is generated according to the reference signal transmission method according to the fourth aspect, a predetermined number of (or subsequent) PUSCH subframes to be transmitted with a UL scheduling grant including a transmission instruction. With the subframe as a reference, the dynamic SRS is multiplexed on the final symbol of the subframe in which SRS transmission is earliest from the reference subframe. The subframe in which SRS can be transmitted is RRC-signaled in advance.

  Further, when the Dynamic SRS is generated according to the reference signal transmission method according to the fifth aspect, the Dynamic SRS is multiplexed on the DMRS of the corresponding subframe. Furthermore, when the Dynamic SRS is generated according to the reference signal transmission method according to the sixth aspect, the Dynamic SRS is multiplexed on the PUSCH of the corresponding subframe. Furthermore, when the Dynamic SRS is generated according to the reference signal transmission method according to the seventh aspect, the Dynamic SRS is multiplexed on the PUSCH and DMRS of the corresponding subframe. Furthermore, when the Dynamic SRS is generated according to the reference signal transmission method according to the eighth aspect, the Dynamic SRS is multiplexed into a resource block different from the resource block assigned to the mobile station apparatus 10 in the corresponding subframe. Furthermore, when the Dynamic SRS is generated according to the reference signal transmission method according to the ninth aspect, the Dynamic SRS is multiplexed on the first symbol of the PUSCH of the corresponding subframe. Furthermore, when the Dynamic SRS is generated according to the reference signal transmission method according to the tenth aspect, the Dynamic SRS is multiplexed over the first symbol of the PUSCH of the corresponding subframe.

  The semi-static SRS signal generation unit 143 generates a semi-static SRS according to the UL scheduling grant. The semi-static SRS mapping unit 144 maps the semi-static SRS based on the SRS multiplexing information notified by RRC signaling. In this case, the Semi-static SRS is mapped to the final symbol of the subframe after 4 subframes after receiving the UL scheduling grant notification. Then, the Semi-static SRS mapped to the radio resource is output to the inverse fast Fourier transform unit (IFFT) 145.

  On the other hand, the transmission data instructed from the upper layer is input to the data channel signal generation unit 146. The data channel signal generation unit 146 generates an uplink data channel signal (PUSCH) based on information included in the uplink scheduling grant. The data channel signal is channel-coded by a channel code / modulation unit (not shown), modulated, and then output to a discrete Fourier transform (DFT) 147. Then, the discrete Fourier transform is performed by the DFT unit 147, and the time series signal is converted into the frequency domain signal, which is then output to the PUSCH mapping unit 148.

  The PUSCH mapping unit 148 performs data channel signal (PUSCH) mapping based on resource block allocation information included in the uplink scheduling grant. Then, the mapped data channel signal (PUSCH) is output to the inverse fast Fourier transform unit (IFFT) 145.

  In the IFFT unit 145, the data channel signal from the PUSCH mapping unit 148 and the Semi-static SRS from the Semi-static SRS mapping unit 144 or the Dynamic SRS from the Dynamic SRS mapping unit 142 are subjected to inverse fast Fourier transform to be frequency domain Are converted to time-series signals and then output to the cyclic prefix adding unit 149. The cyclic prefix adding unit 149 adds a cyclic prefix to the time-series transmission signal. The transmission signal to which the cyclic prefix is added is output to the transmission / reception unit 13. The transmission signal input to the transmission / reception unit 13 is transmitted to the base station apparatus 20 in the uplink via the amplifier unit 12 and the transmission / reception antenna 11.

  Thus, in mobile station apparatus 10 according to the present embodiment, dynamic SRS is multiplexed in a specific subframe in accordance with UL scheduling grant including a dynamic SRS transmission instruction, and thus dynamic SRS is multiplexed. As compared to the case where SRS is periodically multiplexed into subframes regardless of the presence of PUSCH, radio resources used for transmission of Dynamic SRS are used more efficiently. It becomes possible to do.

  FIG. 16 is a functional block diagram of the baseband signal processing unit 24 included in the base station apparatus 20 according to the present embodiment. 16 shows only the configuration related to the reference signal transmission method according to the present invention for convenience of explanation, the baseband signal processing unit 24 shown in FIG. 16 has a configuration included in a normal baseband processing unit. It shall be.

  The received signal input to the baseband signal processing unit 24 is subjected to Fourier transform in the fast Fourier transform unit (FFT) 241 after the cyclic prefix added to the received signal is removed in the CP removal unit 240, and in the frequency domain. Converted to a signal. Among the received signals converted into frequency domain signals, the received signal related to PUSCH is output to PUSCH demapping section 242 and demapped in the frequency domain by PUSCH demapping section 242.

  The reception signal demapped by the PUSCH demapping unit 242 is output to the inverse discrete Fourier transform unit (IDFT) 245. In the inverse discrete Fourier transform unit (IDFT) 245, an inverse discrete Fourier transform process is performed on the received signal to return the frequency domain signal to a time domain signal. Then, the received signal, which is a time-domain signal, is demodulated and decoded based on the transmission format (coding rate, modulation scheme) by the data channel demodulation / decoding unit 246 to reproduce the received data.

  On the other hand, among the received signals converted into frequency domain information by the fast Fourier transform unit 241, the received signal related to the Semi-static SRS is output to the Semi-static SRS demapping unit 243, and the received signal related to the Dynamic SRS The data is output to the SRS demapping unit 244. In this case, the received signal related to the semi-static SRS is received when the mobile station apparatus 10 to be communicated is an LTE terminal. On the other hand, the received signal related to Dynamic SRS is received when the mobile station apparatus 10 to be communicated is an LTE-A terminal to which the reference signal transmission method according to the present invention is applied.

  The received signal related to the Semi-static SRS is demapped in the frequency domain by the Semi-static SRS demapping unit 243 and output to the uplink channel quality measuring unit 247. Similarly, a received signal related to Dynamic SRS is demapped in the frequency domain by Dynamic SRS demapping section 244. In the reference signal transmission method according to the fourth aspect of the present invention, subframe information capable of transmitting SRS is provided to Dynamic SRS demapping section 244, and the SRS multiplexed in the subframe capable of transmitting SRS is decoded. Map. The demapped SRS is output to uplink channel quality measurement section 247. The uplink channel quality measurement unit 247 measures the uplink channel quality based on the received signal related to the Semi-static SRS or Dynamic SRS demapped in the frequency domain.

  The measured channel quality information is output to the uplink scheduler 248. The uplink scheduler 248 performs scheduling for transmitting PUSCH from the mobile station apparatus 10 based on the channel quality information. The scheduling information determined by the uplink scheduler 248 is output to the scheduling grant signal generation unit 249.

  For example, when a dynamic SRS is transmitted from the mobile station apparatus 10 according to the reference signal transmission method according to the first and second aspects, the uplink SQ quality measurement unit 247 continuously multiplexes the dynamic SRS to the PUSCH. Based on the channel quality, the channel quality is measured, and the uplink scheduler 248 performs scheduling based on the measurement result. For this reason, since the channel quality at the timing when PUSCH is actually transmitted can be measured, it is possible to perform scheduling reflecting the actual channel state.

  Further, when the Dynamic SRS is transmitted from the mobile station apparatus 10 according to the reference signal transmission method according to the third aspect, the uplink channel quality measurement unit 247 is based on the Dynamic SRS multiplexed before the PUSCH. Channel quality is measured, and scheduling is performed by the uplink scheduler 248 based on the measurement result. Therefore, the channel quality can be measured at a timing approximate to the timing at which the PUSCH is actually transmitted, and the scheduling content can be reflected in the UL scheduling grant including the subsequent transmission instruction. Moreover, when the Dynamic SRS is transmitted from the mobile station apparatus 10 according to the reference signal transmission method according to the fourth aspect, the SRS is transmitted only in a limited subframe that does not collide with broadcast information, RRC control information, and the like. Therefore, the collision between the SRS and the notification information, RRC control information, etc. can be reliably prevented.

  Furthermore, when the Dynamic SRS is transmitted from the mobile station apparatus 10 according to the reference signal transmission methods according to the fifth to eighth aspects, the uplink SQ quality measurement unit 247 uses the Dynamic SRS multiplexed into a plurality of symbols. The channel quality is measured based on the result, and scheduling is performed in the uplink scheduler 248 based on the measurement result. For this reason, compared with the case where SRS is multiplexed only in the last symbol, the base station apparatus 20 can appropriately receive Dynamic SRS, and scheduling can be appropriately performed based on this Dynamic SRS.

Furthermore, when Dynamic SRS is transmitted from the mobile station apparatus 10 according to the reference signal transmission method according to the ninth and tenth aspects, the uplink channel quality measurement unit 247 transmits a data channel signal. The channel quality is measured based on the dynamic SRS multiplexed on the symbol whose demodulation accuracy may be degraded, and scheduling is performed by the uplink scheduler 248 based on the measurement result. For this reason, it is possible to efficiently use radio resources while suppressing deterioration in demodulation accuracy of the data channel signal. In particular, when the Dynamic SRS is transmitted from the mobile station apparatus 10 according to the reference signal transmission method according to the tenth aspect, the broadband resource block (N _RB ) including the resource block (N _RB ) allocated to the mobile station apparatus 10 Since the channel quality can be measured based on the SRS multiplexed on ( _{RB ″} ), it is possible to improve the measurement accuracy of the channel quality.

  The scheduling grant signal generation unit 249 constitutes a generation unit, and generates a UL scheduling grant signal including a dynamic SRS transmission instruction (transmission identification bit) based on the scheduling information input from the uplink scheduler 248. . Also, the scheduling grant signal generation unit 249 generates an UL scheduling grant signal that does not include a dynamic SRS transmission instruction (transmission identification bit) when the mobile station device 10 to be communicated is a terminal that supports the LTE system. To do. Furthermore, the scheduling grant signal generation unit 249 can include a part of the SRS multiplexing information in the UL scheduling grant signal. In the reference signal transmission method according to the fourth aspect of the present invention, the UL scheduling grant shown in the format shown in FIG. 6 (a) or (b) is generated. The UL scheduling grant signal generated by the scheduling grant signal generation unit 249 is transmitted to the mobile station apparatus 10 on the downlink via the transmission / reception unit 23, the amplifier unit 22, and the transmission / reception antenna 21. It should be noted that a transmission means is constituted by the total receiver 23, the amplifier 22, and the transmitting / receiving antenna 21.

  As described above, in the base station apparatus 20 according to the present embodiment, since the UL scheduling grant including the dynamic SRS transmission instruction is transmitted to the mobile station apparatus 10, the transmission of the dynamic SRS is instructed by the UL scheduling grant. Therefore, it is possible to dynamically control a subframe in which Dynamic SRS is multiplexed, and it is possible to efficiently use radio resources used for SRS transmission.

  In addition, channel quality is measured based on Dynamic SRS multiplexed in a specific subframe according to the UL scheduling grant including the transmission instruction, and scheduling for PUSCH transmission in the mobile station apparatus 10 is performed. Since the channel quality at the timing when PUSCH is actually transmitted or at a timing close to this can be measured, it is possible to perform scheduling reflecting the actual channel state.

  Further, when Dynamic SRS is multiplexed on a plurality of symbols in a specific subframe, the base station apparatus 20 can appropriately receive Dynamic SRS as compared with the case where SRS is multiplexed only on the final symbol. Based on this Dynamic SRS, it becomes possible to perform highly accurate scheduling corresponding to the channel quality.

  Next, a modified example of the embodiment of the present invention will be described focusing on differences from the above-described embodiment. This modification relates to transmission power control and transmission timing control of a data channel signal (PUSCH) using an SRS scheduling grant transmitted by the reference signal transmission method according to the eleventh aspect. In this modified example, an SRS whose transmission timing is dynamically controlled is called “Aperiodic SRS”, and an SRS that is periodically transmitted without being dynamically controlled is called “Periodic SRS”. To do. “Aperiodic SRS” may be the same as “Dynamic SRS” in the above embodiment, and “Periodic SRS” may be the same as “Semi-static SRS” in the above embodiment. In this modification, the SRS scheduling grant transmitted by the reference signal transmission method according to the eleventh aspect is referred to as an “Aperidic SRS grant”.

  FIG. 22 is a functional block diagram of the baseband signal processing unit 14 included in the mobile station apparatus 10 according to the modification. In the baseband signal processing unit 14 shown in FIG. 22, only the configuration related to the reference signal transmission method according to the eleventh aspect of the present invention is shown for convenience of explanation. It shall be provided for the configuration provided.

  As illustrated in FIG. 22, the scheduling grant demodulation / decoding unit 1400 demodulates and decodes the scheduling grant transmitted from the base station apparatus 20. Specifically, the scheduling grant demodulation / decoding unit 1400 switches the scheduling grant interpretation method depending on whether or not the demodulated scheduling grant includes an Aperiodic SRS transmission instruction.

  For example, the scheduling grant demodulation / decoding unit 1400, when the demodulated and decoded scheduling grant does not include an Aperiodic SRS transmission instruction (ie, “Aperiodic SRS request” is “0” as shown in FIG. 19A). If the DCI format indicated by the first bit is “0”, the scheduling grant is interpreted as the UL scheduling grant shown in FIG. 19A, and the radio resource allocation information (Resource block It acquires assignment and hopping resource allocation, modulation / coding scheme information (MCS and RV), retransmission information (NDI), transmission power control information (TPC), and the like. The scheduling grant demodulation / decoding unit 1400 inputs the acquired modulation / coding scheme information (MCS and RV) and retransmission information (NDI) to the data channel signal generation unit 1406, and receives radio resource allocation information (Resource block assignment and hopping resource). allocation) is input to the PUSCH mapping unit 1408, and transmission power control information (TPC) is input to the transmission power control unit 1411.

  On the other hand, the scheduling grant demodulation / decoding unit 1400 sets the Aperiodic SRS request to “1” as shown in FIG. 19B when the demodulated and decoded scheduling grant includes an Aperiodic SRS transmission instruction. When configured), the scheduling grant is interpreted as an Aperiodic SRS grant shown in FIG. 19B, and the transmission bandwidth (TxBW), frequency position (Frequency Position), subframe position information (Comb), and cyclic shift Amount (CS), extended transmission power control information (Extended TPC), transmission timing control information (TA), etc. are acquired. Scheduling grant demodulation / decoding section 1400 outputs a cyclic shift amount (CS) to Aperiodic SRS signal generation section 1401, transmission bandwidth (TxBW), frequency position (Frequency Position), subframe position information (Comb), etc. Are output to the Aperiodic SRS mapping unit 1402, the transmission timing control information (TA) is output to the transmission timing control unit 1410, and the extended transmission power control information (Extended TPC) is output to the transmission power control unit 1411.

  The Aperiodic SRS signal generation unit 1401 generates an Aperiodic SRS when the cyclic shift amount (CS) included in the Aperiodic SRS grant is input from the scheduling grant demodulation / decoding unit 1400.

  The Aperiodic SRS mapping section 1402 maps the Aperiodic SRS generated by the Aperiodic SRS signal generation section 1401 to radio resources according to information included in the Aperiodic SRS grant input from the scheduling grant demodulation / decoding section 1400. The Aperiodic SRS mapping unit 1402 outputs the Aperiodic SRS mapped to the radio resource to an inverse fast Fourier transform (IFFT) unit 1405.

  Periodic SRS signal generation section 1403 generates Periodic SRS at a predetermined period. Periodic SRS mapping section 1404 maps Periodic SRS generated by Periodic SRS signal generation section 1403 to radio resources. Periodic SRS mapping section 1404 outputs Periodic SRS mapped to radio resources to IFFT section 1405.

  The data channel signal generation unit 1406 transmits an uplink data channel signal (for transmitting transmission data input from an upper layer based on information included in the UL scheduling grant input from the scheduling grant demodulation / decoding unit 1400). (PUSCH) is generated, and the generated data channel signal is output to a discrete Fourier transform (DFT) unit 1407.

  The DFT unit 1407 performs a discrete Fourier transform process on the data channel signal (PUSCH) input from the data channel signal generation unit 1406. The DFT unit 1407 outputs the data channel signal converted from the time domain to the frequency domain to the PUSCH mapping unit 1408.

  The PUSCH mapping unit 1408 maps the data channel signal input from the DFT unit 1407 to the radio resource indicated by the UL scheduling grant input from the scheduling grant demodulation / decoding unit 1400. PUSCH mapping section 1408 outputs the data channel signal mapped to the radio resource to IFFT section 1405.

  IFFT section 1405 performs inverse fast Fourier transform processing on the data channel signal input from PUSCH mapping section 1408, Periodic SRS input from Periodic SRS mapping section 1404, and Aperiodic SRS input from Aperiodic SRS mapping section 1402 I do. The IFFT unit 1405 outputs the data channel signal (PUSCH), Periodic SRS, or Aperiodic SRS converted from the frequency domain to the time domain to a CP (Cyclic Prefix) adding unit 1409 as a transmission signal.

  CP adding section 1409 adds a cyclic prefix to the time domain transmission signal input from IFFT section 1405 and outputs the result to transmission timing control section 1410.

  The transmission timing control unit 1410 controls the transmission timing of the transmission signal output from the CP adding unit 1409 according to the transmission timing control information (TA). Here, the transmission timing control information (TA) is information indicating the transmission timing of the transmission signal, and is included in the RACH Response transmitted from the base station apparatus 20 when the mobile station apparatus 10 is initially accessed. The transmission timing control information (TA) is also included in an Aperiodic SRS grant that is transmitted irregularly from the base station apparatus 20. When the transmission timing control information (TA) included in the Aperiodic SRS grant is input from the scheduling grant demodulation / decoding unit 1400, the transmission timing control unit 1410 performs transmission according to the timing control information (TA) included in the Aperiodic SRS grant. Controls signal transmission timing.

  The transmission power control unit 1411 controls the transmission power of the transmission signal according to transmission power control information (TPC) or extended transmission power control information (Extended TPC). Here, the transmission power control information (TPC) is 2-bit information included in the UL scheduling grant as described above, and increases or decreases the transmission power in four stages. Further, as described above, the extended transmission power control information (Extended TPC) is 4-bit information included in the Aperiodic SRS grant, and increases or decreases the transmission power in 16 stages.

More specifically, the transmission power control unit 1411 controls the transmission power of the transmission signal at timing i according to the following equation.
_{P PUSCH (i) = min {} P CMAX, 10log 10, (M PUSCH (i)) + Po_ PUSCH (j) + α · PL + Δ TF (i) + f (i)}
Here, P _CMAX is the maximum transmission power, M _PUSCH (i), the transmission bandwidth at the timing _i, Po_ _PUSCH (i) is the target received power of the propagation loss in the timing I in the case of a 0, alpha is The weighting factor of fractional TPC, PL is a measured value of propagation loss, Δ _TF (i) is an offset at timing i depending on MCS (modulation and coding scheme), and f (i) is the transmission power control information described above. (TPC) or a correction value at timing i based on extended transmission power control information (Extended TPC).

  When the transmission power control information (TPC) included in the UL scheduling grant is input from the scheduling grant demodulation / decoding unit 1400, the transmission power control unit 1411 shows the correction value f (i) at the timing i in FIG. Increase or decrease in 4 steps as shown. On the other hand, when the extended transmission power control information (Extended TPC) included in the Aperiodic SRS grant is input from the scheduling grant demodulation / decoding unit 1400, the transmission power control unit 1411 sets the correction value f (i) at the timing i in FIG. Increase or decrease in 16 steps as shown in (b).

  The transmission signal whose transmission power is controlled by the transmission power control unit 1411 is input to the transmission / reception unit 13 in FIG. 13 and transmitted to the base station apparatus 20 via the amplifier unit 12 and the transmission / reception antenna 11.

  Thus, in the mobile station device 10 according to the modified example, even when transmission of the data channel signal (PUSCH) is resumed, the mobile station device 10 transmits the Aperiodic SRS transmitted from the base station device 20. According to the extended transmission power control information (Extended TPC) included in the grant, the transmission power of the data channel signal (PUSCH) after the predetermined time can be appropriately set. Similarly, according to the transmission timing control information (TA) included in the Aperiodic SRS grant transmitted from the base station apparatus 20, the mobile station apparatus 10 can appropriately set the transmission timing of the data channel signal after the predetermined time has elapsed.

  FIG. 23 is a functional block diagram of the baseband signal processing unit 24 included in the base station apparatus 20. In the baseband signal processing unit 24 shown in FIG. 23, only the configuration related to the reference signal transmission method according to the eleventh aspect of the present invention is shown for convenience of explanation. It shall be provided for the configuration provided.

  CP removal section 2400 removes the cyclic prefix from the received signal input from baseband signal processing section 24 in FIG. 14 and outputs the result to fast Fourier transform (FFT) section 2401.

  The FFT unit 2401 performs a fast Fourier transform process on the received signal input from the CP removal unit 2400. The FFT section 2401 outputs the received signal related to PUSCH to the PUSCH demapping section 2402 among the received signals converted from the time domain to the frequency domain, and outputs the received signal related to Periodic SRS to the Periodic SRS demapping section 2403. A received signal related to SRS is output to Aperiodic SRS demapping section 2404.

  PUSCH demapping section 2402 demaps the received signal related to PUSCH input from FFT section 2401 in the frequency domain. The PUSCH demapping unit 2402 outputs the demapped received signal to the inverse discrete Fourier transform (IDFT) unit 2405.

  The IDFT unit 2405 performs an inverse discrete Fourier transform process on the received signal input from the PUSCH demapping unit 2402. IDFT section 2405 outputs the received signal converted from the frequency domain to the time domain to data channel demodulation / decoding section 2406.

  The data channel demodulation / decoding unit 2406 performs demodulation processing and decoding processing on the reception signal input from the IDFT unit 2405 based on the transmission format (modulation scheme and coding rate). Received data is reproduced by such demodulation processing and decoding processing.

  Periodic SRS demapping section 2403 demaps the received signal related to Periodic SRS input from FFT section 2401 in the frequency domain. Periodic SRS demapping section 2403 outputs the demapped received signal to uplink channel quality measurement section 2407.

  Aperiodic SRS demapping section 2404 demaps the received signal related to Aperiodic SRS input from FFT section 2401 in the frequency domain. Aperiodic SRS demapping section 2404 outputs the demapped received signal to uplink channel quality measurement section 2407.

  The uplink channel quality measurement unit 2407 measures the uplink channel quality based on the received signal related to Periodic SRS or based on the received signal related to Aperiodic SRS. The uplink channel quality measurement unit 2407 outputs the measured uplink channel quality to the transmission power / transmission timing control unit 2410.

  Based on the uplink channel quality input from the uplink channel quality measurement unit 2407, the transmission power / transmission timing control unit 2410 transmits transmission power control information (TPC), extended transmission power control information (Extended TPC), and transmission timing. Generate control information (TA). The transmission power control information (TPC) controls transmission power of an uplink data channel signal (PUSCH) in four steps based on uplink channel quality. In addition, the extended transmission power control information (Extended TPC) is based on the uplink channel quality and the transmission power of the Aperiodic SRS and uplink data channel signal (PUSCH) is expanded from the transmission power control information (TPC). Control is performed within a control range (for example, 16 steps), and is generated when an Aperiodic SRS grant transmission trigger is detected. As a transmission trigger of the Aperiodic SRS grant, for example, the scheduling grant signal generation unit 2409 receives that a scheduling request from the mobile station apparatus 10 is received after a predetermined time has elapsed since the previous scheduling request (that is, the mobile station apparatus 10 is interrupted). To attempt to resume transmission of the data channel signal (PUSCH)). The transmission timing control information (TA) controls the transmission timing of the uplink data channel signal (PUSCH) based on the uplink channel quality, and when the transmission trigger of the Aperiodic SRS grant is detected Is generated. The transmission power / transmission timing control unit 2410 constitutes transmission power control means and transmission timing control means.

  The uplink scheduler 2408 performs scheduling for transmitting PUSCH from the mobile station apparatus 10 based on the uplink channel quality measured by the uplink channel quality measurement unit 2407. The uplink scheduler 2408 includes scheduling information determined by scheduling, transmission power control information (TPC) determined by the transmission power / transmission timing control unit 2410, extended transmission power control information (Extended TPC), transmission timing control information ( TA) is output to scheduling grant signal generation section 2409.

  The scheduling grant signal generation unit 2409 constitutes a generation unit, and generates a scheduling grant based on the scheduling information input from the uplink scheduler 2408. Specifically, the scheduling grant signal unit 2409 generates the UL scheduling grant shown in FIG. 19A in response to the scheduling request from the mobile station apparatus 10. Also, the scheduling grant signal unit 2409 generates the Aperiodic SRS grant shown in FIG. 19B when the transmission trigger of the Aperiodic SRS grant as described above is detected. The UL scheduling grant signal or the Aperiodic SRS grant signal generated by the scheduling grant signal generation unit 2409 is transmitted to the mobile station apparatus 10 on the downlink via the transmission / reception unit 23, the amplifier unit 22, and the transmission / reception antenna 21. The transmission / reception unit 23, the amplifier unit 22, and the transmission / reception antenna 21 constitute transmission means.

  As described above, in the base station apparatus 20 according to the modified example, based on Periodic SRS periodically transmitted from the mobile station apparatus 10 even in a period in which the data channel signal (PUSCH) transmitted from the mobile station apparatus 10 does not exist. Thus, the uplink channel quality can be measured. Therefore, the base station apparatus 20 reflects the channel state closer to the timing at which the transmission of the data channel signal (PUSCH) from the mobile station apparatus 10 is resumed, so that the extended transmission power control information (Extend TPC) or the transmission timing control information (TA) can be set. Further, since the extended transmission power control information (Extended TPC) in which the transmission power control range is expanded can be set, even when the transmission of the suspended data channel signal (PUSCH) is resumed in the mobile station apparatus 10 ( That is, the transmission power of the data channel signal (PUSCH) can be appropriately set in a wide control range even when the uplink channel state is significantly different from the previous transmission time of the data channel signal (PUSCH).

  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.

DESCRIPTION OF SYMBOLS 1 Mobile communication system 10 Mobile station apparatus 11 Transmission / reception antenna 12 Amplifier part 13 Transmission / reception part 14 Baseband signal processing part 15 Application part 140 Scheduling grant demodulation / decoding part 141 Dynamic SRS signal generation part 142 Dynamic SRS mapping part 143 Semi-static SRS signal Generation unit 144 Semi-static SRS mapping unit 145 Inverse Fast Fourier Transform unit (IFFT)
146 Data channel signal generation unit 147 Discrete Fourier transform unit (DFT)
148 PUSCH mapping unit 149 cyclic prefix (CP) addition unit 1400 scheduling grant demodulation / decoding unit 1401 Aperiodic SRS signal generation unit 1402 Aperiodic SRS mapping unit 1403 periodic SRS signal generation unit 1404 Aperiodic SRS mapping unit 1405 inverse fast Fourier transform unit (IFFT) )
1406 Data channel signal generation unit 1407 Discrete Fourier transform unit (DFT)
1408 PUSCH mapping unit 1409 cyclic prefix (CP) addition unit 1410 transmission timing control unit 1411 transmission power control unit 20 base station device 21 transmission / reception antenna 22 amplifier unit 23 transmission / reception unit 24 baseband signal processing unit 25 call processing unit 26 transmission path interface 240 Cyclic Prefix (CP) Removal Unit 241 Fast Fourier Transform Unit (FFT)
242 PUSCH demapping unit 243 Semi-static SRS demapping unit 244 Dynamic SRS demapping unit 245 Inverse discrete Fourier transform unit (IDFT)
246 Data channel demodulation / decoding unit 247 Uplink channel quality measurement unit 248 Uplink scheduler 249 Scheduling grant signal generation unit 2400 Cyclic prefix (CP) removal unit 2401 Fast Fourier transform unit (FFT)
2402 PUSCH demapping unit 2403 Periodic SRS demapping unit 2404 Aperiodic SRS demapping unit 2405 Inverse discrete Fourier transform unit (IDFT)
2406 Data channel demodulation / decoding section 2407 Uplink channel quality measurement section 2408 Uplink scheduler 2409 Scheduling grant signal generation section 2410 Transmission power / transmission timing control section 30 Upper station apparatus 40 Core network 50 Cell

Claims (11)

  A step of transmitting an uplink scheduling grant including an SRS (Sounding Reference Signal) transmission instruction from the base station apparatus, and a step of transmitting an SRS from the mobile station apparatus in response to an SRS transmission instruction included in the uplink scheduling grant. The mobile station apparatus includes a PUSCH (Physical Uplink Shared Channel) subframe in which transmission is instructed by the uplink scheduling grant, or a subframe after a predetermined number of subframes from the PUSCH subframe. A reference signal transmission method comprising transmitting an SRS in a subframe capable of transmitting the earliest SRS.   The reference signal transmission method according to claim 1, wherein the mobile station apparatus transmits an SRS in the same subframe as a PUSCH (Physical Uplink Shared Channel) for which transmission is instructed by the uplink scheduling grant.   The reference signal transmission method according to claim 1, wherein the mobile station apparatus transmits an SRS in a subframe immediately before a PUSCH subframe in which transmission is instructed by the uplink scheduling grant.   The reference signal transmission method according to claim 1, wherein the mobile station apparatus transmits an SRS in a subframe that is a predetermined number before a PUSCH subframe in which transmission is instructed by the uplink scheduling grant.   The reference signal transmission method according to claim 1, wherein the base station apparatus notifies the mobile station apparatus of resource information for multiplexing the SRS by using the uplink scheduling grant and higher layer signaling together. .   When the base station apparatus notifies the mobile station apparatus of part of resource information for multiplexing SRSs from a plurality of mobile station apparatuses including the mobile station apparatus on the same symbol, using the uplink scheduling grant, The reference signal transmission method according to claim 1, wherein a part of the resource information uses another control bit constituting the uplink scheduling grant.   A receiving unit that receives an uplink scheduling grant including an SRS transmission instruction from the base station apparatus, and a PUSCH subframe in which transmission is instructed by the uplink scheduling grant, or a predetermined number of subframes after the PUSCH subframe. A multiplexing unit that multiplexes SRS in the earliest subframe that can be transmitted with SRS, and a transmission unit that transmits the SRS multiplexed by the multiplexing unit to the base station apparatus. A mobile station device.   The mobile station apparatus according to claim 7, wherein the multiplexing unit multiplexes the final symbol of the same subframe as the PUSCH in which transmission is instructed by the uplink scheduling grant.   The mobile station apparatus according to claim 7, wherein the multiplexing unit multiplexes the final symbol of the subframe immediately before the PUSCH subframe for which transmission is instructed by the uplink scheduling grant. A generation unit that generates an uplink scheduling grant including a transmission instruction of SRS, a transmission unit that transmits the uplink scheduling grant generated by the generation unit to a mobile station device, and is transmitted from the mobile station device according to the transmission instruction A receiving unit for receiving the SRS,
The SRS includes the subframe of PUSCH (Physical Uplink Shared Channel) for which transmission is instructed by the uplink scheduling grant, or a subframe after a predetermined number of subframes from the subframe of the PUSCH. The base station apparatus is characterized by being transmitted from the mobile station apparatus in a subframe. The base station apparatus according to claim 10, wherein the transmission section transmits resource information for multiplexing the SRS to the mobile station apparatus by using the uplink scheduling grant and higher layer signaling together.

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