JP5526203B2 - Mobile communication system, base station apparatus, mobile terminal apparatus, and communication control method - Google Patents

Description

  The present invention relates to a base station device, a mobile terminal device, and a communication control method 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, low delay, and the like (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 transmission rate of about 300 Mbps at the maximum in the downlink and about 75 Mbps in 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 the LTE system is also being studied for the purpose of further widening and speeding up (for example, LTE advanced or LTE enhancement (hereinafter referred to as “LTE-A”). ))). Therefore, in the future, it is expected that the plurality of mobile communication systems will coexist, and a configuration (base station apparatus, mobile terminal apparatus, etc.) that can support these plurality of systems may be required.

  In the downlink of the LTE system (for example, Rel. 8), CRS (Cell-specific Reference Signal) is defined. This CRS is used for demodulation of user data, downlink channel quality (CQI: Channel Quality Indicator) measurement for scheduling and adaptive control, and an average downlink propagation path for cell search and handover. Used for state measurement (mobility measurement). On the other hand, in the downlink of the LTE successor system (for example, Rel. 10), CSI-RS (Channel State Information-Reference Signal) is studied exclusively for CSI (Channel State Information) measurement.

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

  By the way, the mobile terminal apparatus of such a system (for example, Rel. 10) is capable of MIMO (Multiple-Input Multiple-Output) transmission by a plurality of antennas. In MIMO transmission, a number of CSI-RSs corresponding to the number of antennas (Tx) of the base station apparatus are transmitted to the mobile terminal apparatus. In future systems, it is assumed that MIMO transmission by more antennas will be supported and the number of reference signals such as CSI-RS will increase.

  The present invention has been made in view of such a point, and even when the number of reference signals increases as the number of antennas increases, a base station apparatus, a mobile terminal apparatus, and a communication control method that can appropriately transmit and receive reference signals The purpose is to provide.

The mobile communication system of the present invention is a mobile communication system comprising a base station apparatus that transmits a channel state measurement reference signal according to the number of antennas of a mobile terminal apparatus and a plurality of mobile terminal apparatuses, wherein the base station apparatus Notifies the first mobile terminal apparatus of the resource to which the reference signal is allocated, and notifies the second mobile terminal apparatus of the resource to which the reference signal is allocated. A reference signal notification unit for notifying the resource as a resource to be muted, wherein the first mobile terminal apparatus receives a notification of a resource to which the reference signal is allocated, and a downlink channel state based on the reference signal The second mobile terminal apparatus receives a notification of a resource to which the reference signal is allocated and a resource to be muted, and receives the reference And measuring a channel state of the downlink based on the item.

  According to the present invention, a first mobile terminal apparatus capable of receiving reference signals from a large number of antennas and a second mobile terminal apparatus capable of receiving reference signals from a smaller number of antennas than the first mobile terminal apparatus. And a reference signal can be notified respectively. Further, the first mobile terminal apparatus can estimate the channel state by receiving reference signals from a plurality of antennas of the base station apparatus. The second mobile terminal apparatus can receive the reference signals from the plurality of antennas of the base station apparatus, ignore the reference signals of the resources notified as muting, and measure the channel state from some reference signals. Therefore, the second mobile terminal apparatus can measure the reference signal without being affected by the increase in the number of antennas of the base station apparatus.

It is explanatory drawing of the allocation pattern of CSI-RS in a resource block. It is explanatory drawing of the muting in the CQI measurement using CSI-RS. It is a figure which shows an example of the muting notification method. It is a figure which shows an example of the arrangement configuration of CSI-RS at the time of changing a base station apparatus from 4TxMIMO transmission to 8TxMIMO transmission. It is a figure which shows an example of the notification method of the positional information on CSI-RS. It is a figure which shows another example of the notification method of the positional information on CSI-RS. It is explanatory drawing of the system configuration | structure of a radio | wireless communications system. It is explanatory drawing of the whole structure of a base station apparatus. It is explanatory drawing of the whole structure of a mobile terminal device. It is a functional block diagram corresponding to the 1st notification method by a base station apparatus. It is a functional block diagram corresponding to the 1st notification method by a 4Tx and 8Tx mobile terminal device. It is a functional block diagram corresponding to the 2nd notification method by a base station apparatus. It is a functional block diagram corresponding to the 2nd notification method by 4Tx and 8Tx mobile terminal apparatus.

  First, with reference to FIG. 1, a CSI-RS that is one of reference signals applied in an LTE successor system (for example, Rel. 10) will be described. CSI-RS is a reference signal used for CSI measurement such as CQI (Channel Quality Indicator), PMI (Precoding Matrix Indicator), and RI (Rank Indicator) as channel states. CSI-RS is assigned at a predetermined period, for example, 10 subframe periods, unlike CRS assigned to all subframes. The CSI-RS is specified by parameters such as position, sequence, and transmission power. The position of CSI-RS includes a subframe offset, a period, and a subcarrier-symbol offset (index).

  The CSI-RS is a control signal such as PDCCH (Physical Downlink Control Channel), user data such as PDSCH (Physical Downlink Shared Channel), CRS (Cell-specific Reference Signal) and DM- in one resource block defined by LTE. It is assigned so as not to overlap with other reference signals such as RS (Demodulation-Reference Signal). One resource block includes 12 subcarriers continuous in the frequency direction and 14 symbols continuous in the time axis direction. From the viewpoint of suppressing PAPR, two resource elements adjacent in the time axis direction are assigned as a set to resources that can transmit CSI-RS.

  In the CSI-RS configuration shown in FIG. 1, 40 resource elements are secured as CSI-RS resources (reference signal resources). In this 40 resource element, a CSI-RS pattern is set according to the number of CSI-RS ports (number of antennas, etc.). In each CSI-RS pattern, one resource element is allocated for CSI-RS per one CSI-RS port. When the number of CSI-RS ports is 2, CSI-RS is allocated to two resource elements out of 40 resource elements. Therefore, in FIG. 1A, 20 CSI-RS patterns indicated by indexes # 0 to # 19 (CSI Configuration = 0-19) are set. Here, for convenience of explanation, the same index is attached to the resource elements constituting one pattern.

  When the number of CSI-RS ports is 4, CSI-RS is allocated to 4 resource elements out of 40 resource elements. Therefore, in FIG. 1B, 10 CSI-RS patterns indicated by indexes # 0 to # 9 (CSI Configuration = 0-9) are set. When the number of CSI-RS ports is 8, CSI-RS is allocated to 8 resource elements out of 40 resource elements. Therefore, as shown in FIG. 1C, five CSI-RS patterns indicated by indexes # 0- # 4 (CSI Configuration = 0-4) are set. Note that, in the CSI-RS pattern, user data or the like is assigned to resource elements to which CSI-RS is not assigned.

  In CSI-RS, interference between cells is suppressed by selecting a different CSI-RS pattern (CSI Configuration) for each cell. In addition to the FDD normal pattern shown in FIGS. 1A to 1C, the CSI-RS pattern may be a pattern in which an additional pattern of TDD is added as an option of FDD as shown in FIG. 1D. Also, an extended pattern (not shown) obtained by expanding the normal pattern of FDD may be used. In the following description, a normal pattern of FDD will be described as an example for convenience of description.

  By the way, in CSI measurement using CSI-RS, measurement accuracy may deteriorate due to data interference from adjacent cells. For example, as shown in FIG. 2A, user data is allocated to the downlink resource block of the cell C1 corresponding to the CSI-RS of the adjacent cell C2. Further, user data is allocated to the downlink resource block of the cell C2 corresponding to the CSI-RS of the adjacent cell C1. These user data constitute an interference component of CSI-RS in each cell, and cause deterioration in CSI measurement accuracy in a mobile terminal apparatus located at the boundary between the cells C1 and C2.

  Muting is being studied in order to improve the degradation of CSI measurement accuracy caused by the user data allocation position. In muting, as shown in FIG. 2B, user data is not allocated to resources corresponding to CSI-RSs of neighboring cells. The downlink resource block of the cell C1 is muted corresponding to the CSI-RS of the cell C2. Further, the downlink resource block of the cell C2 is muted corresponding to the CSI-RS of the cell C1.

  With this configuration, the CSI-RS interference component caused by the user data of the neighboring cell is eliminated, and the CSI measurement accuracy in the mobile terminal apparatus is improved. When mutual muting is performed between adjacent cells, it is necessary to notify the mobile terminal device of the muting position because the data channel of the own cell is not transmitted for the adjacent cells. This is because the base station apparatus performs rate matching while avoiding resources to be muted, and the mobile terminal apparatus needs to recognize resources to be muted and perform derate matching. If the mobile terminal apparatus does not recognize the resource to be muted, the demodulation process is also performed on the muted resource, so that the throughput and demodulation accuracy of the demodulation process deteriorate.

  Note that the resource to be muted may be defined as a resource to which no data is allocated, or may be defined as a resource to which data is allocated to an extent that does not interfere with CSI-RSs of neighboring cells. Furthermore, the muted resource may be defined as a resource that is transmitted with a transmission power that does not interfere with the CSI-RS of the neighboring cell.

  When a base station apparatus notifies muting with respect to a mobile terminal apparatus, it notifies using a CSI-RS pattern. In this case, the muting may be notified in a bitmap format in which an index (CSI Configuration) numbered in the CSI-RS pattern and the presence / absence of muting are associated one-to-one. Moreover, you may use the CSI-RS pattern from which the number of CSI-RS ports differs by the notification of muting and the notification of CSI-RS.

  FIG. 3 shows an example in which muting is notified to a mobile terminal apparatus that supports MIMO transmission of four transmission ports (Tx). As shown in FIG. 3, muting is set for the CSI-RS resource indicated by index # 6 (CSI Configuration = 6). In this case, corresponding to the index [# 0- # 9, # 20- # 25] (CSI Configuration = 0-9, 20-25) obtained by adding the TDD additional pattern to the FDD normal pattern shown in FIG. 1D, 16-bit bitmap information [0000001000000000] is notified. In the bitmap information, “1” is set for resources to be muted, and “0” is set for resources that are not muted. In addition to the bitmap information, the base station apparatus notifies the mobile terminal apparatus of a transmission cycle (Duty Cycle) and a subframe offset.

  Also, the base station apparatus notifies the CSI-RS to the mobile terminal apparatus that supports 4Tx MIMO using the CSI-RS pattern when the number of CSI-RS ports is 4. Here, the CSI-RS is assigned to the CSI-RS resource indicated by index # 1 (CSI Configuration = 1) in FIG. 1B. The base station apparatus notifies the mobile terminal apparatus of resources to which CSI-RS is allocated in addition to muting information.

  By the way, 2TxMIMO transmission, 4TxMIMO transmission, and 8TxMIMO transmission are supported in the mobile terminal apparatus of the LTE successor system (for example, Rel. 10 or later). However, 8Tx MIMO transmission may be selectively used for mobile terminal devices. In this case, the mobile terminal apparatus supports 2TxMIMO transmission and 4TxMIMO transmission at the start of operation of the successor system, but may not support 8TxMIMO transmission. For this reason, when a base station apparatus that supports 4Tx MIMO transmission at the start of operation of the successor system is upgraded for 8Tx MIMO transmission, communication with a mobile terminal apparatus that does not support 8Tx MIMO transmission becomes a problem.

  Signaling differs between a mobile terminal device that supports 4Tx MIMO transmission (hereinafter referred to as a 4Tx mobile terminal device) and a mobile terminal device that supports 8Tx MIMO transmission (hereinafter referred to as an 8Tx mobile terminal device). Therefore, since the 4Tx mobile terminal apparatus does not support 8Tx signaling, there is a possibility that the 4Tx mobile terminal apparatus cannot be connected to the base station apparatus. Also, as shown in FIG. 4, when the base station apparatus is upgraded from 4Tx MIMO transmission to 8Tx MIMO transmission, the number of CSI-RS ports increases from 4 to 8. Therefore, even when the 4Tx mobile terminal apparatus can be connected to the base station apparatus for 8Tx MIMO transmission, the increased CSI-RS cannot be recognized and interference occurs when demodulating user data, resulting in a significant deterioration in reception characteristics.

  For example, in the example of FIG. 4, when the base station apparatus is upgraded from 4Tx MIMO transmission to 8Tx MIMO transmission, the CSI-RS indicated by “4-7” is changed to CSI-RS in addition to the CSI-RS indicated by “0-3”. -Assigned to RS resources. Note that “0-7” in FIG. 4 indicates a CSI-RS port number. The base station apparatus can notify CSI-RS position information indicated by “0-7” to the 8Tx mobile terminal apparatus, but CSI− indicated by “4-7” for the 4Tx mobile terminal apparatus. Cannot notify RS.

  Therefore, the present inventors have arrived at the present invention to solve these problems. That is, the gist of the present invention notifies a new mobile terminal device (for example, an 8Tx mobile terminal device) of resources to which CSI-RSs corresponding to the number of antennas are allocated, and an existing mobile terminal device (for example, 4Tx). The mobile terminal device) is notified of a resource to which CSI-RS excluding the increment is allocated by muting. By doing so, even if the base station apparatus is upgraded from 4Tx MIMO transmission to 8Tx MIMO transmission, a 4Tx mobile terminal apparatus that does not support 8Tx MIMO transmission can appropriately receive CSI-RS.

  Here, a notification method of CSI-RS location information in the present embodiment will be described. FIG. 5 is a diagram illustrating an example of a CSI-RS location information notification method. In the following description, it is assumed that the 4Tx mobile terminal device and the 8Tx mobile terminal device are located in the same cell. Further, in the following description, a configuration in which the base station apparatus is upgraded from 4Tx MIMO transmission to 8Tx MIMO transmission will be described as an example, but it can be changed as appropriate. For example, the base station apparatus may be upgraded from 2Tx MIMO transmission to 8Tx MIMO transmission.

  FIG. 5A shows an example of CSI-RS allocation to an 8Tx mobile terminal apparatus. Here, 40 resource elements are secured as CSI-RS resources in one resource block. Moreover, one resource element is allocated for CSI-RS per antenna (transmission port). The 8Tx mobile terminal apparatus is notified using a CSI-RS port number = 8 CSI-RS pattern (see FIG. 1C). Here, the CSI-RS is assigned to the resource indicated by index # 1 (CSI Configuration = 1).

  In this embodiment, one CSI-RS is assigned to one antenna in one resource block, but a plurality of CSI-RSs may be assigned to one antenna. Also, CSI-RS allocation is performed avoiding CSI-RS of neighboring cells in order to suppress inter-cell interference of CSI-RS. In this case, the position information of CSI-RS between cells may be defined in advance between adjacent base station apparatuses, or may be dynamically changed between adjacent base station apparatuses.

  On the other hand, as shown in FIG. 5B, since the 4Tx mobile terminal apparatus supports 4Tx MIMO transmission, it can receive four CSI-RSs in one resource block. For this reason, the 4Tx mobile terminal apparatus cannot receive all CSI-RSs allocated in the resource block. Therefore, the base station apparatus notifies the 4Tx mobile terminal apparatus of the resource to which the increased amount of CSI-RS is allocated as the muted resource. The resource to be muted is notified using the CSI-RS pattern shown in FIG. 1D. Here, the resource indicated by index # 6 (CSI Configuration = 6) is notified as a muted resource.

  This resource is actually assigned a CSI-RS, but is recognized as a resource to be muted by the 4Tx mobile terminal apparatus. Therefore, the 4Tx mobile terminal apparatus ignores the CSI-RS of the resource notified as muting and receives only the CSI-RS of the resource indicated by index # 1 (CSI Configuration = 1). In addition, since the 4Tx mobile terminal device ignores the CSI-RS of the resource recognized as muting when demodulating user data, the demodulation accuracy and throughput of the user data are not reduced.

  In this configuration, the location information of CSI-RS can be notified from the base station apparatus to the mobile terminal apparatus by the first notification method and the second notification method. The first notification method is a method in which CSI-RS position information is individually notified from the base station apparatus to the 4Tx and 8Tx mobile terminal apparatuses. The second notification method is a method of simultaneously reporting CSI-RS position information from the base station apparatus to the 4Tx and 8Tx mobile terminal apparatuses.

  As illustrated in FIG. 5C, in the first notification method, the base station apparatus individually notifies the 8Tx mobile terminal apparatus of CSI-RS position information using an 8Tx CSI-RS pattern. Further, the base station apparatus individually notifies the 4Tx mobile terminal apparatus of the CSI-RS position information by the CSI-RS pattern for 4Tx and replaces the increased CSI-RS position information with the mui. Notification information individually.

  For example, the base station apparatus may individually notify resources on which CSI-RSs are arranged to 4Tx and 8Tx mobile terminal apparatuses using CSI Configuration information indicating a CSI-RS pattern. As shown in FIG. 5A, the base station apparatus uses five CSI Configurations to notify the 8Tx mobile terminal apparatus of CSI-RS position information. The base station apparatus notifies CSI Configuration = 1 indicating index # 1 as CSI-RS position information. As shown in FIG. 5B, the base station apparatus uses 10 CSI Configurations to notify the 4Tx mobile terminal apparatus of CSI-RS position information. The base station apparatus notifies CSI Configuration = 1 indicating index # 1 as CSI-RS position information and also notifies muting information.

  In this case, the base station apparatus may individually notify the 4Tx mobile terminal apparatus of muting information in the bitmap format described above. The base station apparatus has 16 bits as muting information corresponding to an index [# 0- # 9, # 20- # 25] (CSI Configuration = 0-9, 20-25) obtained by adding an additional pattern to a normal pattern. Of the bitmap information [0000001000000000]. In the bitmap information, “1” is set for resources to be muted, and “0” is set for resources that are not muted. In the bitmap information, “0” may be set for muting resources, and “1” may be set for resources that are not muted. Moreover, although the bitmap information is composed of 16 bits, it may be composed of 10 bits excluding the additional pattern.

  As shown in FIG. 5D, in the second notification method, the base station apparatus notifies the 4Tx and 8Tx mobile terminal apparatuses of CSI-RS location information all together using the 4Tx and 8Tx CSI-RS patterns. . Further, the base station apparatus notifies 4Tx muting information all at once. In this case, the 8Tx mobile terminal apparatus ignores the 4Tx notification and acquires the position information of the CSI-RS for 8Tx. Further, the 4Tx mobile terminal apparatus ignores the 8Tx notification and acquires the 4Tx CSI-RS position information and muting information.

  For example, the base station apparatus may simultaneously notify resources on which CSI-RSs are arranged to 4Tx and 8Tx mobile terminal apparatuses using CSI Configuration information indicating a CSI-RS pattern. The base station apparatus notifies CSI Configuration = 1 indicating index # 1 for the 8Tx mobile terminal apparatus (see FIG. 5A) and CSI Configuration = 1 indicating index # 1 for the 4Tx mobile terminal apparatus (see FIG. 5B). To be notified. Further, the base station apparatus may notify the 4Tx and 8Tx mobile terminal apparatuses of muting information all at once in the bitmap format described above. In this case, the base station apparatus notifies 16-bit bitmap information [0000001000000000] as muting information. This 4Tx muting information is ignored in the 8Tx mobile terminal apparatus.

  Moreover, the base station apparatus may notify all the CSI-RS position information to the 4Tx mobile terminal apparatus by a CSI-RS pattern with the number of CSI-RS ports = 8. That is, by signaling the 4Tx mobile terminal apparatus to use a subset of the CSI-RS of the 8Tx mobile terminal apparatus, the signaling amount of CSI-RS location information can be reduced. In this case, the base station apparatus notifies the 4Tx mobile terminal apparatus of muting information of some resources. Note that the base station apparatus may be configured not to notify the 4Tx mobile terminal apparatus of muting information. For example, a resource capable of receiving CSI-RS and a resource recognized as muting are set in advance for a 4Tx mobile terminal apparatus. Thereby, for example, the 4Tx mobile terminal apparatus receives the CSI-RS from the first to fourth antennas (CSI-RS port numbers) and receives the CSI-RS from the fifth to eighth antennas (CSI-RS port numbers). RS can be ignored. Therefore, the signaling amount of muting information can be reduced.

  Next, another example of the CSI-RS location information notification method will be described with reference to FIG. FIG. 6 is a diagram illustrating another example of the CSI-RS location information notification method. FIG. 6 illustrates a configuration in which the CSI-RS for 4Tx mobile terminal devices and the CSI-RS for 8Tx mobile terminal devices are allocated to different resources.

  FIG. 6A shows an example of CSI-RS allocation to an 8Tx mobile terminal apparatus. Here, 40 resource elements are secured as CSI-RS resources in one resource block. The 8Tx mobile terminal apparatus can receive eight CSI-RSs in one resource block. Here, the resource indicated by index # 1 (CSI Configuration = 1) is notified as CSI-RS location information. However, the 8Tx mobile terminal apparatus cannot receive the CSI-RS for the 4Tx mobile terminal apparatus. Therefore, the base station apparatus notifies the 8Tx mobile terminal apparatus of the CSI-RS resource for the 4Tx mobile terminal apparatus as a muted resource. The resource to be muted is notified using the CSI-RS pattern shown in FIG. 1D. Here, the resource indicated by index # 0 (CSI Configuration = 0) is notified as a muted resource.

  This resource is actually assigned a CSI-RS, but is recognized by the 8Tx mobile terminal device as a resource to be muted. Therefore, the 8Tx mobile terminal apparatus ignores the CSI-RS of the resource notified as muting and receives only the CSI-RS of the resource indicated by index # 1 (CSI Configuration = 1). In addition, since the 8Tx mobile terminal apparatus ignores the CSI-RS of the resource recognized as muting when demodulating user data, the demodulation accuracy and throughput of the user data are not reduced.

  On the other hand, as shown in FIG. 6B, the 4Tx mobile terminal apparatus can receive four CSI-RSs in one resource block. Here, the resource indicated by index # 0 (CSI Configuration = 0) is notified as CSI-RS position information. However, the 4Tx mobile terminal device cannot receive the CSI-RS for the 8Tx mobile terminal device. Therefore, the base station apparatus notifies the 4Tx mobile terminal apparatus of the CSI-RS resource for the 8Tx mobile terminal apparatus as a muted resource. The resource to be muted is notified using the CSI-RS pattern shown in FIG. 1D. Here, the resources indicated by indexes # 1 and # 6 (CSI Configuration = 1, 6) are notified as muted resources.

  This resource is actually assigned a CSI-RS, but is recognized as a resource to be muted by the 4Tx mobile terminal apparatus. Therefore, the 4Tx mobile terminal apparatus ignores the CSI-RS of the resource notified as muting and receives only the CSI-RS of the resource indicated by index # 0 (CSI Configuration = 0). In addition, since the 4Tx mobile terminal device ignores the CSI-RS of the resource recognized as muting when demodulating user data, the demodulation accuracy and throughput of the user data are not reduced.

  Also in this configuration, the location information of CSI-RS can be notified from the base station apparatus to the mobile terminal apparatus by the first notification method and the second notification method. The first notification method is a method in which CSI-RS position information is individually notified from the base station apparatus to the 4Tx and 8Tx mobile terminal apparatuses. The second notification method is a method of simultaneously reporting CSI-RS position information from the base station apparatus to the 4Tx and 8Tx mobile terminal apparatuses.

  As shown in FIG. 6C, in the first notification method, the base station apparatus individually notifies CSI-RS position information to the 8Tx mobile terminal apparatus using a CSI-RS pattern for 8Tx, and mu Notification information individually. Furthermore, the base station apparatus notifies the 4Tx mobile terminal apparatus of the CSI-RS position information individually using the 4Tx CSI-RS pattern and also notifies the muting information individually.

  For example, the base station apparatus may individually notify resources on which CSI-RSs are arranged to 4Tx and 8Tx mobile terminal apparatuses using CSI Configuration information indicating a CSI-RS pattern. As shown in FIG. 6A, the base station apparatus notifies CSI Configuration = 1 indicating index # 1 to the 8Tx mobile terminal apparatus. As shown in FIG. 6B, the base station apparatus notifies CSI Configuration = 0 indicating index # 0 to the 4Tx mobile terminal apparatus.

  Also, the base station apparatus may individually notify muting information to the 4Tx and 8Tx mobile terminal apparatuses in the above-described bitmap format. The base station apparatus notifies 16-bit bitmap information [1000000000000000] to the 8Tx mobile terminal apparatus. Also, the base station apparatus notifies 16-bit bitmap information [0100001000000000] to the 4Tx mobile terminal apparatus.

  As shown in FIG. 6D, in the second notification method, the base station apparatus notifies the 4Tx and 8Tx mobile terminal apparatuses of CSI-RS position information all together using the 4Tx and 8Tx CSI-RS patterns. . In addition, the base station apparatus simultaneously notifies 4Tx and 8Tx muting information. In this case, the 8Tx mobile terminal apparatus ignores the 4Tx notification and acquires the 8Tx CSI-RS position information and muting information. Further, the 4Tx mobile terminal apparatus ignores the 8Tx notification and acquires the 4Tx CSI-RS position information and muting information.

  For example, the base station apparatus may simultaneously notify resources on which CSI-RSs are arranged to 4Tx and 8Tx mobile terminal apparatuses using CSI Configuration information indicating a CSI-RS pattern. The base station apparatus notifies CSI Configuration = 1 (see FIG. 6A) indicating index # 1 for 8Tx mobile terminal apparatus and CSI Configuration = 0 (FIG. 6B) indicating index # 0 for 4Tx mobile terminal apparatus. Notice.

  Further, the base station apparatus may notify the 4Tx and 8Tx mobile terminal apparatuses of muting information all at once in the bitmap format described above. In this case, the base station apparatus notifies 16-bit bitmap information [1000000000000000] for the 8Tx mobile terminal apparatus and also notifies 16-bit bitmap information [0100001000000000] for the 4Tx mobile terminal apparatus. The muting information for 8Tx is ignored in the 4Tx mobile terminal device, and the muting information for 4Tx is ignored in the 8Tx mobile terminal device.

  In this case, instead of the configuration in which the muting information is notified from the base station apparatus to the 4Tx and 8Tx mobile terminal apparatuses, the resource to which the CSI-RS other than the own apparatus is allocated to the 4Tx and 8Tx mobile terminal apparatuses is muted May be recognized as In this case, settings are made in advance so that both 4Tx and 8Tx notifications can be received by the 4Tx and 8Tx mobile terminal devices. Thereby, the signaling amount of muting information can be reduced.

  In each configuration illustrated above, the base station apparatus transmits a transmission cycle (Duty Cycle), a subframe offset, and the like to the 4Tx and 8Tx mobile terminal apparatuses in addition to the resources and muting resources in which the CSI-RS is arranged. Notify them. Further, the location information of the CSI-RS may be notified by higher layer signaling, or may be notified by a broadcast channel, a control channel, and a data channel.

  Moreover, in each structure illustrated above, the 1st, 2nd notification method is not limited to the said method. For example, the base station apparatus may notify CSI-RS position information to a 4Tx, 8Tx mobile terminal apparatus in a bitmap format. Further, the base station apparatus may notify the 4Tx, 8Tx mobile terminal apparatus of muting information by CSI Configuration information indicating a CSI-RS pattern. Moreover, you may notify combining a separate notification and simultaneous notification.

  Moreover, the index numbered by the CSI-RS pattern shown in FIG.5 and FIG.6 is an example, and can be changed suitably. The notification for 4Tx and 8Tx may be identified by each mobile terminal apparatus by an identification bit or the like. Further, the 8Tx mobile terminal apparatus is not limited to a new mobile terminal apparatus, and may be any mobile terminal apparatus that supports MIMO transmission applied to the base station apparatus. Further, the 4Tx mobile terminal apparatus is not limited to an existing mobile terminal apparatus, and may be a mobile terminal apparatus that does not support or selectively supports MIMO transmission applied to the base station apparatus.

  Here, the radio communication system according to the present embodiment will be described in detail. FIG. 7 is an explanatory diagram of a system configuration of the wireless communication system according to the present embodiment. Note that the radio communication system shown in FIG. 7 is a system including, for example, an LTE system or a successor system. In this radio communication system, carrier aggregation in which a plurality of fundamental frequency blocks with the system band of the LTE system as a unit is integrated is used. Moreover, this radio | wireless communications system may be called IMT-Advanced, and may be called 4G.

  As shown in FIG. 7, the wireless communication system 1 includes base station apparatuses 20A and 20B and a plurality of 8Tx and 4Tx mobile terminal apparatuses 10A and 10B communicating with the base station apparatuses 20A and 20B. . The base station devices 20 </ b> A and 20 </ b> B are connected to the higher station device 30, and the higher station device 30 is connected to the core network 40. The base station devices 20A and 20B are connected to each other by wired connection or wireless connection. Each of the mobile terminal devices 10A and 10B can communicate with the base station devices 20A and 20B in the cells C1 and C2. 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.

  Each of the mobile terminal apparatuses 10A and 10B includes an LTE terminal and an LTE-A terminal. In the following description, unless otherwise specified, the description will be given as a 4Tx and 8Tx mobile terminal apparatus. For convenience of explanation, it is assumed that the mobile terminal devices 10A and 10B communicate wirelessly with the base station devices 20A and 20B, but more generally user devices (including mobile terminal devices and fixed terminal devices). UE: User Equipment).

  In the radio communication system 1, OFDMA (Orthogonal Frequency Division Multiple Access) is applied to the downlink and SC-FDMA (Single Carrier-Frequency Division Multiple Access) is applied to the uplink as the radio access scheme. The wireless access method is not limited to this. 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. .

Here, the communication channel will be described.
The downlink communication channel includes a PDSCH (Physical Downlink Shared Channel) as a downlink data channel shared by the mobile terminal apparatuses 10A and 10B, and downlink L1 / L2 control channels (PDCCH, PCFICH, PHICH). User data and higher control information are transmitted by the PDSCH. PDSCH and PUSCH scheduling information and the like are transmitted by PDCCH (Physical Downlink Control Channel). The number of OFDM symbols used for PDCCH is transmitted by PCFICH (Physical Control Format Indicator Channel). HARQ ACK / NACK for PUSCH is transmitted by PHICH (Physical Hybrid-ARQ Indicator Channel).

  The uplink communication channel has a PUSCH (Physical Uplink Shared Channel) as an uplink data channel shared by each mobile terminal apparatus and a PUCCH (Physical Uplink Control Channel) which is an uplink control channel. User data and higher control information are transmitted by this PUSCH. Also, downlink radio quality information (CQI: Channel Quality Indicator), ACK / NACK, and the like are transmitted by PUCCH.

  The overall configuration of the base station apparatus according to the present embodiment will be described with reference to FIG. Note that the base station apparatuses 20A and 20B have the same configuration and will be described as the base station apparatus 20. Further, each of the mobile terminal devices 10A and 10B has the same configuration, and therefore will be described as the mobile terminal device 10. The base station apparatus 20 includes a plurality of transmission / reception antennas 201 for MIMO transmission, an amplifier unit 202, a transmission / reception unit (notification unit) 203, a baseband signal processing unit 204, a call processing unit 205, and a transmission path interface 206. And.

  User data transmitted from the base station apparatus 20 to the mobile terminal apparatus 10 via the downlink is input from the higher station apparatus 30 to the baseband signal processing unit 204 via the transmission path interface 206.

  In the baseband signal processing unit 204, 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 transmission processing, scheduling, transmission format selection, channel coding, inverse fast Fourier transform (IFFT) processing, and precoding processing are performed and transferred to each transceiver 203. The downlink control channel signal is also subjected to transmission processing such as channel coding and inverse fast Fourier transform, and is transferred to each transceiver 203.

  Further, the baseband signal processing unit 204 notifies the mobile terminal apparatus 10 of control information for communication in the cell through the broadcast channel. Information for communication in the cell includes, for example, system bandwidth in uplink or downlink, resource block information allocated to the mobile terminal apparatus 10, precoding information for precoding in the mobile terminal apparatus 10, PRACH ( Root sequence identification information (Root Sequence Index) for generating a random access preamble signal in the physical random access channel) is included. Precoding information may be transmitted via an independent control channel such as PHICH.

  Each transmission / reception unit 203 converts the baseband signal output by precoding for each antenna from the baseband signal processing unit 204 to a radio frequency band. The amplifier unit 202 amplifies the frequency-converted radio frequency signal and transmits the amplified signal using the transmission / reception antenna 201.

  On the other hand, for data transmitted from the mobile terminal apparatus 10 to the base station apparatus 20 via the uplink, radio frequency signals received by the respective transmitting / receiving antennas 201 are amplified by the amplifier sections 202 and frequency-converted by the respective transmitting / receiving sections 203. Are converted into baseband signals and input to the baseband signal processing unit 204.

  The baseband signal processing unit 204 performs FFT processing, IDFT processing, error correction decoding, MAC retransmission control reception processing, RLC layer, and PDCP layer reception processing on user data included in the input baseband signal. The data is transferred to the higher station apparatus 30 via the transmission path interface 206.

  The call processing unit 205 performs call processing such as communication channel setting and release, state management of the base station apparatus 20, and radio resource management.

  Next, the overall configuration of the mobile terminal apparatus according to the present embodiment will be described with reference to FIG. Since the LTE main unit and the LTE-A terminal have the same hardware configuration, they will be described without distinction. The mobile terminal apparatus 10 includes a plurality of transmission / reception antennas 101 for MIMO transmission, an amplifier unit 102, a transmission / reception unit 103, a baseband signal processing unit 104, and an application unit 105.

  For downlink data, radio frequency signals received by a plurality of transmission / reception antennas 101 are respectively amplified by an amplifier unit 102, converted in frequency by a transmission / reception unit 103, 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 104. Among the downlink data, downlink user data is transferred to the application unit 105. The application unit 105 performs processing related to layers higher than the physical layer and the MAC layer. Also, broadcast information in the downlink data is also transferred to the application unit 105.

  On the other hand, uplink user data is input from the application unit 105 to the baseband signal processing unit 104. In the baseband signal processing unit 104, transmission processing for retransmission control (H-ARQ (Hybrid ARQ)), channel coding, precoding, DFT processing, IFFT processing, and the like are performed and transferred to each transmission / reception unit 103. The transmission / reception unit 103 converts the baseband signal output from the baseband signal processing unit 104 into a radio frequency band. Thereafter, the amplifier unit 102 amplifies the frequency-converted radio frequency signal and transmits the amplified signal using the transmission / reception antenna 101.

  With reference to FIG. 10, the functional block of the base station apparatus corresponding to the 1st notification method is demonstrated. In addition, each functional block of FIG. 10 mainly shows a simplified processing content of the baseband processing unit, and has a configuration normally provided in the baseband processing unit. Moreover, in the following description, it demonstrates mainly corresponding to the allocation structure of CSI-RS shown in FIG.

  In the first notification method illustrated in FIG. 10, the base station apparatus 20 includes a CSI-RS allocation unit 211, a CSI-RS location information generation unit 212, a muting information generation unit 213, and a CSI-RS parameter generation unit 214. A downlink control signal generation unit 215, a performance information acquisition unit 217, and a transmission / reception unit 203. The performance information acquisition unit 217 acquires performance information by signaling (UE Capability) from each of the mobile terminal apparatuses 10A and 10B. The performance information is, for example, MIMO transmission that can be supported by the mobile terminal apparatuses 10A and 10B, the number of antennas that can be supported, and the like.

  The CSI-RS allocation unit 211 allocates the CSI-RS to the 8Tx CSI-RS resource. Thereby, CSI-RS is assigned not only to the 8Tx mobile terminal apparatus 10A but also to the 4Tx mobile terminal apparatus 10B. Note that the CSI-RS allocation unit 211 may allocate CSI-RSs to different resources for the mobile terminal apparatuses 10A and 10B that support different MIMO transmissions.

  The CSI-RS position information generation unit 212 generates CSI-RS position information allocated by the CSI-RS allocation unit 211. The location information of CSI-RS includes a transmission cycle (Duty Cycle), a subframe offset, and the like in addition to resources to which CSI-RS is allocated. A resource to which CSI-RS is allocated is specified by CSI Configuration information, bitmap information, or the like. The position information of CSI-RS is individually generated for each mobile terminal apparatus, and is input to downlink control signal generation section 215 as one of CSI-RS parameters.

  The muting information generation unit 213 generates muting information that causes the mobile terminal apparatus to recognize a resource to which an extra CSI-RS is allocated as a resource to be muted. The resource indicated by the muting information is actually assigned CSI-RS and is not muted. Bitmap information and CSI Configuration are generated as muting information. The muting information is individually generated for each mobile terminal device based on the performance information acquired by the performance information acquisition unit 217, and is input to the downlink control signal generation unit 215.

  The CSI-RS parameter generation unit 214 generates parameters such as a CSI-RS sequence and transmission power other than the CSI-RS position information. The CSI-RS parameter generated in the CSI-RS parameter generation unit 214 is input to the downlink control signal generation unit 215.

  The downlink control signal generation unit 215 generates a downlink control signal for each of the mobile terminal apparatuses 10A and 10B, including CSI-RS position information, CSI-RS parameters, and muting information. As a result, the 8Tx mobile terminal device 10A is individually notified of all resources to which the CSI-RS is assigned by the location information of the CSI-RS for 8Tx. Also, the 4Tx mobile terminal apparatus 10B is individually notified of some CSI-RS resources by the location information of CSI-RS for 4Tx and the remaining CSI-RS by the muting information. The transmission / reception unit 203 transmits the CSI-RS and the downlink control signal to the mobile terminal apparatuses 10A and 10B.

  With reference to FIG. 11, the functional blocks of the 4Tx and 8Tx mobile terminal devices corresponding to the first notification method will be described. In addition, each functional block of FIG. 11 mainly shows the processing contents of the baseband processing unit in a simplified manner, and is assumed to have a configuration normally provided in the baseband processing unit.

  As illustrated in FIG. 11, the 8Tx mobile terminal apparatus 10A includes a transmission / reception unit 103A, an acquisition unit 111A, a measurement unit 112A, and a user data demodulation unit 113A. The transceiver 103A receives the CSI-RS and the downlink control signal from the base station device 20. The acquisition unit 111A acquires CSI-RS position information and CSI-RS parameters by demodulating the downlink control signal and analyzing the contents of the signal. Note that the acquiring unit 111A can also acquire muting information when the muting information is included in the downlink control signal.

  The measurement unit 112A measures CSI from parameters such as CSI-RS position information, series, and transmission power. The user data demodulation unit 113A demodulates user data received via the transmission / reception unit 103A. Note that the 8Tx mobile terminal apparatus 10A may receive CSI-RS position information and CSI-RS parameters by higher layer signaling. In addition, when muting information is included in the downlink control signal, user data demodulation section 113A demodulates user data by ignoring the resource indicated in the muting information together with the resource indicated in the CSI-RS position information. .

  The 4Tx mobile terminal apparatus 10B includes a transmission / reception unit 103B, an acquisition unit 111B, a measurement unit 112B, and a user data demodulation unit 113B. The transceiver 103B receives the CSI-RS and the downlink control signal from the base station apparatus 20. The acquisition unit 111B acquires CSI-RS position information, CSI-RS parameters, and muting information by demodulating the downlink control signal and analyzing the contents of the signal.

  The measurement unit 112B measures CSI from parameters such as CSI-RS position information, series, and transmission power. The user data demodulation unit 113B demodulates user data received via the transmission / reception unit 103B. In this case, the user data demodulation unit 113B recognizes a resource to which an extra CSI-RS is allocated as a muted resource, based on the muting information notified from the base station apparatus 20. For this reason, the user data demodulation unit 113B does not demodulate the resource to which the CSI-RS is allocated and the muted resource, that is, performs rate matching, thereby improving the throughput and demodulation accuracy of the demodulation process. Note that the 4Tx mobile terminal apparatus 10B may receive CSI-RS position information, CSI-RS parameters, and muting information by higher layer signaling.

  With reference to FIG. 12, the functional block of the base station apparatus corresponding to the 2nd notification method is demonstrated. In addition, each functional block of FIG. 12 mainly shows the processing contents of the baseband processing unit in a simplified manner, and is assumed to have a configuration normally provided in the baseband processing unit. In FIG. 12, blocks having the same names as those in FIG. Moreover, in the following description, it demonstrates mainly corresponding to the allocation structure of CSI-RS shown in FIG.

  In the second notification method illustrated in FIG. 12, the base station apparatus 20 includes a CSI-RS allocation unit 211, a CSI-RS position information generation unit 212a for 8Tx, a CSI-RS position information generation unit 212b for 4Tx, It includes an 8Tx muting information generation unit 213a, a 4Tx muting information generation unit 213b, a CSI-RS parameter generation unit 214, a notification signal generation unit 216, and a transmission / reception unit 203. In this configuration as well, a performance information acquisition unit may be provided to acquire performance information of the mobile terminal device and vary the notification.

  The CSI-RS allocation unit 211 allocates the CSI-RS to the 8Tx CSI-RS resource. Thereby, CSI-RS is assigned not only to the 8Tx mobile terminal apparatus 10A but also to the 4Tx mobile terminal apparatus 10B. Note that the CSI-RS allocation unit 211 may allocate CSI-RSs to different resources for the mobile terminal apparatuses 10A and 10B that support different MIMO transmissions.

  The CSI-RS position information generation unit 212a generates 8Tx CSI-RS position information allocated by the CSI-RS allocation unit 211 for the 8Tx mobile terminal apparatus 10A. The CSI-RS position information generation unit 212b generates 4Tx CSI-RS position information allocated by the CSI-RS allocation unit 211 for the 4Tx mobile terminal apparatus 10B. The location information of CSI-RS includes a transmission cycle (Duty Cycle), a subframe offset, and the like in addition to resources to which CSI-RS is allocated. A resource to which CSI-RS is allocated is specified by CSI Configuration, bitmap information, or the like. The CSI-RS position information is input to the broadcast signal generation unit 216 as one of the CSI-RS parameters.

  The muting information generation unit 213a generates 8Tx muting information that causes the 8Tx mobile terminal apparatus 10A to recognize a resource to which an extra CSI-RS is assigned as a muted resource. The muting information generation unit 213b generates 4Tx muting information that causes the 4Tx mobile terminal apparatus 10B to recognize a resource to which an extra CSI-RS is allocated as a muted resource. The resources indicated in these muting information are actually assigned CSI-RS and are not muted. Bitmap information and CSI Configuration are generated as muting information. The muting information is input to the notification signal generation unit 216.

  The CSI-RS parameter generation unit 214 generates parameters such as a CSI-RS sequence and transmission power other than the CSI-RS position information. The CSI-RS parameter generated in the CSI-RS parameter generation unit 214 is input to the notification signal generation unit 216.

  The broadcast signal generation unit 216 generates a broadcast signal including 4Tx and 8Tx CSI-RS position information, CSI-RS parameters, 4Tx and 8Tx muting information. As a result, 4Tx and 8Tx CSI-RS position information, CSI-RS parameters, 4Tx and 8Tx muting information are simultaneously broadcast to the 8Tx mobile terminal apparatus 10A and the 4Tx mobile terminal apparatus 10B. The The transmission / reception unit 203 transmits the CSI-RS and the notification signal to each of the mobile terminal devices 10A and 10B.

  With reference to FIG. 13, the functional blocks of the 4Tx and 8Tx mobile terminal devices corresponding to the second notification method will be described. In addition, each functional block of FIG. 13 mainly shows the processing contents of the baseband processing unit in a simplified manner, and is assumed to have a configuration normally provided in the baseband processing unit. In FIG. 13, blocks having the same names as those in FIG.

  As illustrated in FIG. 13, the 8Tx mobile terminal apparatus 10A includes a transmission / reception unit 103A, an acquisition unit 111A, a measurement unit 112A, and a user data demodulation unit 113A. The transceiver 103A receives the CSI-RS and the broadcast signal from the base station apparatus 20. The acquisition unit 111A demodulates the notification signal and analyzes the contents of the signal, thereby ignoring the 4Tx notification and acquiring the 8Tx CSI-RS position information and CSI-RS parameters. Note that the acquisition unit 111A can also acquire muting information when muting information for 8Tx is included in the notification signal.

  The measurement unit 112A measures CSI from parameters such as CSI-RS position information, series, and transmission power. The user data demodulation unit 113A demodulates user data received via the transmission / reception unit 103A. Note that the 8Tx mobile terminal apparatus 10A may receive CSI-RS position information and CSI-RS parameters by higher layer signaling. Also, when muting information is included in the notification signal, user data demodulation section 113A demodulates user data ignoring the resources indicated in the muting information together with the resources indicated in the CSI-RS position information.

  The 4Tx mobile terminal apparatus 10B includes a transmission / reception unit 103B, an acquisition unit 111B, a measurement unit 112B, and a user data demodulation unit 113B. The transceiver 103B receives the CSI-RS and the broadcast signal from the base station device 20. The acquisition unit 111B demodulates the notification signal and analyzes the contents of the signal, thereby ignoring the 8Tx notification and acquiring the 4Tx CSI-RS position information, CSI-RS parameters, and muting information. .

  The measurement unit 112B measures CSI from parameters such as CSI-RS position information, series, and transmission power. The user data demodulation unit 113B demodulates user data received via the transmission / reception unit 103B. In this case, the user data demodulation unit 113B recognizes a resource to which an extra CSI-RS is assigned as a muted resource based on the muting information notified from the base station apparatus 20. For this reason, the user data demodulation unit 113B does not demodulate the resource to which the CSI-RS is allocated and the muted resource, that is, performs rate matching, thereby improving the throughput and demodulation accuracy of the demodulation process. Note that the 4Tx mobile terminal apparatus 10B may receive CSI-RS position information, CSI-RS parameters, and muting information by higher layer signaling.

  As described above, according to base station apparatus 20 according to the present embodiment, even when upgraded from 4Tx MIMO transmission to 8Tx MIMO transmission, 8Tx mobile terminal apparatus 10A and 4Tx mobile terminal apparatus 10B are CSI-RS can be received. For the 4Tx mobile terminal apparatus 10B, the channel state can be measured by ignoring the CSI-RS of the resource indicated in the muting information among the CSI-RSs notified from the base station apparatus 20. Therefore, the 4Tx mobile terminal apparatus 10B can receive the CSI-RS without being affected by the upgrade of the base station apparatus 20.

  In the above-described embodiment, the first and second notification methods are illustrated, but the CSI-RS location information notification method is not limited to this. The CSI-RS location information notification method notifies the 8Tx mobile terminal apparatus of at least resources to which CSI-RS is allocated, and notifies the 4Tx mobile terminal apparatus of resources to which CSI-RS is allocated. In this case, any method may be used as long as a part of resources are notified as muted resources.

  In the above-described embodiment, the acquisition unit acquires the CSI-RS position information, muting information, and CSI-RS parameters in the mobile terminal device. However, the present invention is not limited to this configuration. . The CSI-RS position information, muting information, and CSI-RS parameters may be acquired by a functional block other than the acquisition unit, for example, a measurement unit or a user data demodulation unit.

  Moreover, in above-mentioned embodiment, although CSI-RS was illustrated as a reference signal, it is not limited to this. The reference signal may be any signal used for channel state measurement. Further, the CSI only needs to include at least one of CQI, PMI, and RI.

  The present invention is not limited to the embodiment described above, and can be implemented with various modifications. For example, unless departing from the scope of the present invention, the CSI-RS setting position, muting setting position, number of processing units, processing procedure, number of CSI-RS, number of mutings, number of antennas in the above description Can be implemented with appropriate changes. Other modifications can be made without departing from the scope of the present invention.

1 wireless communication system 10A 8Tx mobile terminal device (first mobile terminal device)
10B 4Tx mobile terminal device (second mobile terminal device)
20A, 20B Base station apparatus 101 Transmission / reception antenna 103A, 103B Transmission / reception unit (reception unit)
111A, 111B acquisition unit 112A, 112B measurement unit 113A, 113B user data demodulation unit 201 transmission / reception antenna 203 transmission / reception unit (reference signal notification unit)
211 CSI-RS allocation unit (reference signal allocation unit)
212 CSI-RS position information generation unit 213 Muting information generation unit 214 CSI-RS parameter generation unit 215 Downlink control signal generation unit (reference signal notification unit)
216 Notification signal generation unit (reference signal notification unit)

Claims (5)

A base station apparatus that can support up to the maximum number of transmission ports as a transmission port of CSI-RS (Channel State Information Reference Signal) that is a reference signal for channel state measurement, and an upper limit of the number of CSI-RS transmission ports that can be supported A mobile communication system having a plurality of different mobile terminal devices,
The base station device
A CSI-RS pattern indicating the arrangement of the CSI-RS on the resource block is determined corresponding to the number of transmission ports from the minimum number of transmission ports to the maximum number of transmission ports. An allocating unit that is allocated to resource elements specified by a CSI-RS pattern corresponding to the number of transmission ports of
A position information generating unit that generates position information of CSI-RS for identifying a resource to which the CSI-RS is allocated;
Muting information indicating that transmission power is muted for a CSI-RS resource element that is not supported by a communication target mobile terminal device among CSI-RSs assigned to the resource element by the assigning unit is generated. A muting information generator,
A CSI-RS allocated to the resource element by the allocation unit, the muting information, and a transmission unit that transmits the location information of the CSI-RS,
The mobile terminal apparatus recognizes that the transmission power is muted based on the muting information and supports the CSI-RS allocated to the resource element of the CSI-RS that is not supported. A mobile communication system characterized by monitoring a CSI-RS resource element and measuring a downlink channel state. The muting information generation unit supports, when a CSI-RS pattern corresponding to the number of transmission ports larger than the upper limit of the number of transmission ports supported by the mobile terminal device is applied to the mobile terminal device to be communicated. The mobile communication system according to claim 1, wherein muting information indicating that transmission power is muted is generated for a resource element to which CSI-RS other than the CSI-RS pattern to be assigned is assigned. Up to the maximum number of transmission ports can be supported as transmission ports of CSI-RS (Channel State Information Reference Signal), which is a reference signal for channel state measurement, and the upper limit of the number of CSI-RS transmission ports that can be handled is different. A base station device that communicates with a mobile terminal device,
A CSI-RS pattern indicating the arrangement of the CSI-RS on the resource block is determined corresponding to the number of transmission ports from the minimum number of transmission ports to the maximum number of transmission ports. An allocating unit that is allocated to resource elements specified by a CSI-RS pattern corresponding to the number of transmission ports of
A position information generating unit that generates position information of CSI-RS for identifying a resource to which the CSI-RS is allocated;
Muting information indicating that transmission power is muted for a CSI-RS resource element that is not supported by a communication target mobile terminal device among CSI-RSs assigned to the resource element by the assigning unit is generated. A muting information generator,
A base station apparatus comprising: a transmission unit that transmits CSI-RS allocated to a resource element by the allocation unit, the muting information, and position information of the CSI-RS. A base station apparatus that can support up to the maximum number of transmission ports as a transmission port of CSI-RS (Channel State Information Reference Signal) that is a reference signal for channel state measurement, and an upper limit of the number of CSI-RS transmission ports that can be supported In a mobile communication system having a plurality of different mobile terminal devices, the upper limit of the number of CSI-RS transmission ports that can be handled is smaller than the maximum number of transmission ports of the base station device,
A CSI-RS pattern indicating the arrangement of CSI-RS on a resource block is determined corresponding to the number of transmission ports from the minimum number of transmission ports to the maximum number of transmission ports. CSI-RS assigned to the resource element specified by the corresponding CSI-RS pattern, CSI-RS location information for specifying the resource to which the CSI-RS is assigned, and CSI assigned to the resource element A receiving unit that receives from the base station device muting information indicating that transmission power is muted for a resource element of CSI-RS that is not supported by the mobile terminal device among RSs;
For CSI-RSs assigned to unsupported CSI-RS resource elements, based on the muting information, it recognizes that transmission power is muted and supports CSI-RS resources. A measurement unit that monitors the element and measures the downlink channel state;
A mobile terminal apparatus comprising: A base station apparatus that can support up to the maximum number of transmission ports as a transmission port of CSI-RS (Channel State Information Reference Signal) that is a reference signal for channel state measurement, and an upper limit of the number of CSI-RS transmission ports that can be supported A communication control method in a mobile communication system having a plurality of different mobile terminal devices,
In the base station apparatus, a CSI-RS pattern indicating an arrangement of CSI-RS on a resource block is determined corresponding to the number of transmission ports from the minimum number of transmission ports to the maximum number of transmission ports, and Assigning a CSI-RS to a resource element identified by a CSI-RS pattern corresponding to any number of transmission ports;
In the base station device, generating CSI-RS position information for identifying a resource to which the CSI-RS is allocated;
In the base station apparatus, transmission power is muted for a CSI-RS resource element that is not supported by the mobile terminal apparatus to be communicated among the CSI-RS allocated to the resource element by the allocator. Generating muting information; and
In the base station apparatus, transmitting the CSI-RS allocated to the resource element by the allocation unit, the muting information, and the location information of the CSI-RS;
For the CSI-RS assigned to the CSI-RS resource element that is not supported in the mobile terminal apparatus, the mobile terminal apparatus recognizes that the transmission power is muted based on the muting information, and supports the CSI-RS. Monitoring a CSI-RS resource element and measuring a downlink channel state. A communication control method comprising:

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