JP5756815B2 - Method for indicating a specific DMRS antenna port to a user in a wireless communication system - Google Patents

Description

  The present invention relates to a general radio mobile communication system, and more particularly, to a radio mobile using a multiple access scheme using a multi-carrier such as OFDMA (Orthogonal Frequency Division Multiple Access). Transmission / reception method and efficient operation for channel state information reference signal (CSI-RS, channel state measurement reference signal) transmitted by a base station to help a terminal to measure channel quality (radio channel state) in a communication system .

  Current mobile communication systems have evolved from high-speed, high-quality wireless packet data communication systems to provide data services and multimedia services, away from the provision of initial voice-centric services. For this purpose, various standardization organizations such as 3GPP, 3GPP2, and IEEE are proceeding with the 3rd generation evolution mobile communication system standard to which a multiple access scheme using a multi-carrier is applied. In recent years, various mobile communication standards such as 3GPP Long Term Evolution (LTE), 3GPP2 Ultra Mobile Broadband (UMB), and IEEE 802.16m are based on a multiple access method using multi-carrier. Developed to support wireless packet data transmission services.

  Existing 3-generation evolution mobile communication systems such as LTE, UMB, and 802.16m are based on a multi-carrier multiple access scheme, and apply multiple input multiple output (MIMO, multiple antennas) to improve transmission efficiency. In addition, it has a feature of using various techniques such as beam-forming, adaptive modulation and coding (AMC, adaptive modulation and coding) method, and channel sensitive (channel-sensitive) scheduling method. The above-mentioned various technologies concentrate the transmission power transmitted from a large number of antennas by channel quality or adjust the amount of data to be transmitted, and selectively transmit data to users with good channel quality. Use to improve transmission efficiency and improve system capacity performance. Since such a technique mostly operates based on channel state information between a base station (eNB: evolved Node B, BS: Base Station) and a terminal (UE: User Equipment, MS: Mobile Station), the eNB or The UE needs to measure the channel state between the base station and the terminal, and what is used at this time is the Channel Status Indication Reference Signal (CSI-RS). The eNB mentioned above means a downlink transmission and an uplink receiving apparatus located at a certain location, and one eNB performs transmission / reception with respect to a plurality of cells. A plurality of eNBs are geographically dispersed in one mobile communication system, and each eNB performs transmission / reception with respect to a plurality of cells.

  Time, frequency, and power resources are limited in a mobile communication system. Therefore, if more resources are allocated to the reference signal, the resources that can be allocated to the traffic channel (data traffic channel) transmission decrease, and the absolute amount of data to be transmitted may decrease. it can. In such a case, the performance of channel measurement and estimation is improved, but since the absolute amount of data to be transmitted is reduced, the overall system capacity performance can be rather lowered. Therefore, an appropriate allocation between the resources for the reference signal and the signal resources for the traffic channel transmission is necessary so that the optimum performance can be derived in terms of the total system capacity.

  In the 3rd generation evolution wireless mobile communication system standard, the reference signal is divided into a common reference signal (CRS) and a dedicated reference signal (DRS) according to the presence / absence of a dedicated signal for a specific terminal as follows. Divided.

  1) Common Reference Signal: In the 3GPP LTE system, it is also referred to as Cell-specific RS or CRS (Common RS), and is a reference signal transmitted to all terminals of a cell (cell) to which the base station belongs. A reference signal pattern that can be classified by antenna port (antenna port) is defined so that channel estimation and measurement can be performed for transmission using multiple antennas. The LTE system supports up to 4 antenna ports.

  2) Dedicated Reference Signal: A reference signal that is additionally transmitted separately from the common reference signal, and is transmitted only to a specific terminal designated by the base station. In 3GPP LTE (-A) system, it is sometimes called UE-specific RS or DRS, and is generally used when a base station performs data traffic channel transmission using non-codebook based precoding. Is done.

  In the case of the LTE-A system, which is an upgraded system of the LTE system, a DeModulation Reference Signal (demodulation reference signal, DMRS) that enables channel estimation for up to eight layers is also transmitted in addition to the CRS and DRS. The Like the DRS, the DMRS is additionally transmitted separately from the CRS, and is transmitted only to a specific terminal designated by the base station. In LTE-A, a downlink signal is transmitted using an OFDMA transmission scheme that utilizes the frequency domain and the time domain simultaneously. The frequency domain where downlink is transmitted in LTE-A consists of a plurality of RBs composed of 12 subcarriers, and the time domain is composed of subframes composed of 14 OFDM symbols. A radio resource used when one base station performs transmission on the downlink is composed of one or a plurality of RBs in the frequency domain, and is composed of one subframe in the time domain. In addition, a radio resource transmitted by one subcarrier in one OFDM symbol section is referred to as RE (resource element).

  The LTE-A system can perform transmission using a plurality of layers when transmitting by SU-MIMO or MU-MIMO. When transmission is performed for a plurality of layers in this way, DMRS resources must be assigned to each layer. In general, when performing channel estimation using DMRS in LTE-A, a DMRS resource allocated to perform channel estimation for one layer is referred to as a DMRS port. Hereinafter, the terms DMRS resource and DMRS port will be used together.

  FIG. 1 shows a position where DMRS is transmitted with radio resources in LTE-A configured with one RB and one subframe. In FIG. 1, reference numeral 100 denotes Rank 2 DMRS pattern that enables the eNB to perform DMRS transmission for two layers. In the case of transmitting two DMRSs using the Rank 2 DMRS pattern of FIG. 1, DMRSs for each layer are orthogonally spread with a spreading length of 2 at 101 and 102 positions, and then transmitted to the CDM. The DMRS is orthogonally spread and transmitted in this way as well at the 103 and 104 positions. In addition, DMRSs are transmitted in the same manner in consecutive REs displayed in the same shape (blue) in FIG. As a result, DMRS signals for two DMRS antenna ports are transmitted in the same frequency and time domain by the CDM method.

  In FIG. 1, 110 is a Rank 4 DMRS pattern that enables the eNB to perform DMRS transmission for four layers. The Rank 4 DMRS pattern of FIG. 1 transmits a DMRS signal by a method of orthogonally spreading with the same spreading length 2 as 100. A difference between 110 and 100 is that an additional RE is used to perform transmission for four DMRS antenna ports. It can be observed in FIG. 1 that 110 uses twice as much RE to transmit DMRS as compared to 100.

  In FIG. 1, 120 is a Rank 8 DMRS pattern that enables the eNB to perform DMRS transmission for eight layers. It can be seen that the Rank 8 DMRS pattern of FIG. 1 uses the same number of REs as compared to 110 transmitting DMRS for four layers. Thus, in order to transmit signals for eight DMRS antenna ports while using the same number of REs, transmission is performed by orthogonally spreading with a spreading length of 4 at positions 105, 106, 107, and 108.

  The rank of the signal transmitted by the eNB in the LTE-A system is variable depending on the state of the downlink channel. Thus, since the rank of the eNB transmission signal is variable, the DMRS pattern to be used is also variable. That is, when enabling transmission to a layer with many channels depending on the situation, the eNB can use a rank 8 DMRS pattern as shown in 120 of FIG. 1, and enabling transmission only to a layer with few channels. The eNB can use a rank 2 DMRS pattern such as 100 in FIG.

  As described above, the DMRS pattern transmitted by the eNB can change with time, and the DMRS port assigned to one UE in the DMRS pattern may be variable, so that the eNB can downlink traffic to a specific UE. In order to transmit the channel, it is necessary to inform the UE which DMRS antenna port of which DMRS pattern is used to demodulate the downlink traffic channel.

  As shown in FIG. 1, when there are three DMRS patterns and a maximum of eight DMRS antenna ports are possible, one method for the eNB to notify the UE of information regarding DMRS is 2-bit information indicating DMRS pattern. And 8 bits for indicating in a bit map format which one of 8 DMRS antenna ports is to be used. That is, a total of 10 bits are used to notify what DMRS resource is allocated to one UE. As an example, when the Rank 2 DMRS pattern is “00”, the Rank 4 DMRS pattern is “01”, and the Rank 8 DMRS pattern is “10”, the eNB has the information “01” and “01100000”. This information can be notified to the UE that the DMRS antenna port 1, 2 has been assigned in the Rank 4 DMRS pattern.

  Notifying the DMRS resource by the method as described above has a problem that the eNB has to transmit the entire 10-bit information to the UE. Such a number of bits is relatively excessive as compared to information that is actually transmitted, and may cause a reduction in the downlink system capacity.

  Another problem of the method as described above is that a UE that receives information about DMRS resources can only know information about DMRS antenna port assigned to itself, so any DMRS antenna can be transmitted to other UEs. The point is that it is impossible to know whether a port has been allocated. In the case of a wireless communication system in which downlink transmission is performed by MU-MIMO as in the LTE-A system, while one UE receives its own signal, transmission to other UEs is also possible in the same frequency interval and time interval. This fact can be used to implement a more effective receiver algorithm if it can be known that it will be done. As an example, in the case of a MMSE (Minimum Mean Square Error) receiver widely used in modern mobile communication systems, an optimized performance can be obtained if the magnitude of interference is accurately known. In order to accurately measure the magnitude of interference with the MMSE receiver, first, it is necessary to accurately determine the presence or absence of interference, but the DMRS resource notification method described above cannot notify this information to the UE. .

  In order to overcome the limitations and problems of the prior art for notifying DMRS resources in this way, it is possible to efficiently notify the UE of DMRS resources, and at the same time, when transmitting in MU-MIMO, against other UEs that cause interference. There is a need for an effective transmission method for whether or not transmission takes place.

  In the LTE-A system, one eNB can allocate up to eight DMRS antenna ports to one UE. Each antenna port enables the eNB to perform channel estimation for one of a plurality of layers transmitted by MIMO. The eNB notifies which DMRS antenna port is allocated to the UE using a PDCCH (Physical Downlink Control Channel) designed to transmit control information to the UE. Since DMRS antenna port allocation is required for each layer when the eNB performs MIMO transmission, it forms a close relationship with the eNB MIMO transmission scheme. That is, when the eNB performs MIMO transmission that implements three layers, the eNB transmits allocation control information for three DMRS antenna ports to one or a plurality of UEs.

  An object of the present invention is to efficiently notify a UE of DMRS resource allocation information necessary for receiving a downlink traffic signal in the LTE-A system, and simultaneously to the UE in the same frequency interval and time interval as the UE. An object of the present invention is to provide a method for effectively notifying which DMRS resource is used for transmission to a UE.

  A method for interpreting control information of a terminal in a wireless communication system for achieving the object of the present invention includes information on at least one transport block and DMRS (De Modulation Reference Signal) antenna port assignment instruction information. A reception step of receiving control information from a base station, a confirmation step of confirming the number of transmission blocks allocated to the terminal using the control information, and the DMRS antenna port allocation instruction information according to the number of transmission blocks. An interpretation stage to be interpreted.

  Also, the control information transmission method of the base station in the wireless communication system of the present invention includes a confirmation step of confirming the number of transmission blocks allocated to a terminal, and a DMRS (DeModulation Reference Signal) antenna according to the number of confirmed transmission blocks. A selection stage for selecting port allocation instruction information, a generation stage for generating control information including information on at least one transport block and the selected DMRS (DeModulation Reference Signal) antenna port allocation instruction information And a transmission step of transmitting the generated control information to the terminal.

  In addition, a terminal that receives and interprets control information from a base station in the wireless communication system of the present invention receives at least one transport block information and DMRS (DeModulation Reference Signal) antenna port assignment instruction information. A wireless communication unit that receives control information from a base station, and confirms the number of transmission blocks allocated to the terminal using the control information, and interprets the DMRS antenna port allocation instruction information according to the number of transmission blocks And a controller.

  In addition, the base station that transmits control information in the wireless communication system of the present invention checks the number of transmission blocks allocated to the terminal, and determines a DMRS (DeModulation Reference Signal) antenna port allocation instruction according to the number of transmission blocks confirmed. A controller that selects information and generates control information including information on at least one transport block and the selected DMRS (DeModulation Reference Signal) antenna port assignment instruction information; and the generated control information And a wireless communication unit for transmitting the message to the terminal.

  According to the present invention, DMRS resource allocation information necessary for receiving a downlink traffic signal in the LTE-A system is efficiently notified to the UE, and at the same time, other UEs in the same frequency interval and time interval as the UE can be transmitted. It is possible to effectively notify which DMRS resource is used for transmission to the UE.

It is a figure which shows the position where DMRS is transmitted with the radio | wireless resource in LTE-A comprised by one RB and one subframe. It is a figure which shows DMRS antenna port allocation information transmitted by PDCCH by this invention by LTE-A. According to the present invention, the eNB assigns the DMRS antenna port to the UE, and at the same time, the eNB notifies which DMRS antenna port is used for transmission to other UEs that may cause interference in the same frequency and time interval. It is a figure which shows the method to do. According to the present invention, the UE receives the DMRS antenna port assignment index transmitted by the eNB, determines which DMRS antenna port is assigned to itself, and at the same time, may cause interference to the received signal at the same frequency and time interval It is a figure which shows the method a UE judges which transmission with respect to a certain other UE is performed using which DMRS antenna port is performed. FIG. 6 is a diagram illustrating using two scrambled sequences with the same time and frequency resources to distinguish DMRS antenna ports when the number of layers transmitted in MU-MIMO transmission is 3 or 4. According to the present invention, separate 1-bit control information “SU / MU-MIMO Indicator” for distinguishing whether eNB transmission is SU-MIMO or MU-MIMO transmission, and DMRS antenna port allocation control transmitted in association with this information. It is a figure which shows information. When using the SU / MU-MIMO Indicator according to the present invention, at the same time that the eNB assigns the DMRS antenna port to the UE, which DMRS antenna port is transmitted to other UEs that may cause interference in the same frequency and time interval. It is a figure which shows the method to which eNB notifies whether it is performed using. When using the SU / MU-MIMO Indicator according to the present invention, at the same time that the eNB assigns the DMRS antenna port to the UE, which DMRS antenna port is transmitted to other UEs that may cause interference in the same frequency and time interval. It is a figure which shows the method to which eNB notifies whether it is performed using. When using the SU / MU-MIMO indicator according to the present invention, the UE receives the DMRS antenna port allocation index transmitted by the eNB, and determines which DMRS antenna port is allocated to the UE, and at the same frequency and time interval. It is a figure which shows the method in which UE judges which DMRS antenna port is used for transmission with respect to other UE which may cause interference in an own received signal. When using the SU / MU-MIMO indicator according to the present invention, the UE receives the DMRS antenna port allocation index transmitted by the eNB, and determines which DMRS antenna port is allocated to the UE, and at the same frequency and time interval. It is a figure which shows the method in which UE judges which DMRS antenna port is used for transmission with respect to other UE which may cause interference in an own received signal. FIG. 9 is a diagram illustrating a method in which an eNB allocates a DM-RS antenna port using Table 8. When eNB allocates DM-RS antenna port using Table 8, it is a figure which shows the method of a terminal interpreting this. FIG. 6 is a diagram illustrating DMRS antenna port allocation information transmitted on PDCCH in LTE-A according to another embodiment of the present invention. It is a figure which shows the process in which transmission diversity availability is notified using the NDI bit for transport block which is not transmitted by Tables 15 and 16 designed by this invention. FIG. 17 is a diagram illustrating a process of notifying whether transmission is initial or initial transmission using the NDI bit for transport block that is not transmitted in Table 17 designed according to the present invention and whether or not transmission diversity is applicable. FIG. 19 is a diagram illustrating a process of notifying whether to apply Synchronous HARQ using a transport block NDI bit that is not transmitted in Table 18 designed according to the present invention.

  In the LTE-A system, MIMO is divided into SU-MIMO in which all layers transmitted by the eNB are allocated to one UE, and MU-MIMO allocated to two or more UEs. In the case of SU-MIMO, the number of layers that can be allocated to one UE is 1, 2, 3, 4, 5, 6, 7, 8. That is, in the case of SU-MIMO, DMRS antenna port can be allocated to UE by judging from 1 to 8 eNBs. On the other hand, in the case of MU-MIMO, the following restrictions are provided in consideration of implementation complexity.

1. MU-MIMO transmits to a maximum of four UEs using the same frequency resource and time resource.
2. MU-MIMO can allocate only two layers at maximum to one UE.
3. MU-MIMO performs transmission for up to four layers using the same frequency resource and time resource. That is, one layer can be assigned to each of four UEs, or two layers can be assigned to two UEs, but two layers can be assigned to three UEs. I can't.

  Also, SU-MIMO and MU-MIMO can be changed for each frequency section in units of subframe (1 msec) according to eNB's judgment. In the LTE-A system, limiting the transmission of eNBs to a maximum of 4 layers in MU-MIMO may be replaced with the expression limiting the composite rank of MU-MIMO to 4.

  One of the MIMO-related restrictions common to the LTE-A system and the LTE system is that only one transport block can be transmitted to one layer. Here, the transport block is a unit of transmitted traffic information, which is transmitted from the upper layer of the LTE and LTE-A system to the physical layer, encoded, modulated, and transmitted. In the LTE and LTE-A systems, the eNB can transmit up to two transport blocks to one UE by using the same frequency and time resources. At this time, when one transport block is transmitted, the transport is transmitted to one layer to the UE, but when two transport blocks are transmitted, the transport is performed using a minimum of two layers.

  In the present invention, the layer allocation constraints and one transport block of MU-MIMO and SU-MIMO as described above are transmitted to one layer, while two transport blocks are two. A method that can minimize the amount of control information required for notifying the DMRS antenna port assigned to one UE using the above point of transmission to the layer is presented. In addition to this, the eNB notifies the UE whether the signal transmitted by the UE is a part of the MU-MIMO signal or the SU-MIMO that receives the transmission signal alone from the eNB. provide. When the signal transmitted by the UE is a part of the MU-MIMO signal, the DMRS antenna port is notified together with the signal transmitted to the other UE, and is used for measuring and removing the interference component of the UE. Like that.

  In the present invention, the method of notifying the terminal of the DMRS antenna port is performed by utilizing information on the DMRS antenna port and information on the transport block that already exists in the LTE and LTE-A systems. As described above, two transport blocks can always be transmitted using only two or more layers. Also, one transport block is always transmitted only to one layer. When the eNB transmits PDSCH, which is a traffic channel in LTE and LTE-A, to the UE, it notifies the UE whether transmission for one transport block or transmission for two transport blocks is performed. Control information to be transmitted is mounted on the PDCCH and transmitted. The present invention links information related to such transport block and information that allocates DMRS antenna port, and notifies DMRS antenna port allocated to each UE with a minimum amount of control information.

  FIG. 2 shows DMRS antenna port allocation information transmitted on PDCCH according to the present invention in LTE-A.

  In FIG. 2, DMRS antenna port allocation information (or DMRS resource indicator, hereinafter the same) is described as “control information DMRS antenna port indication”, and a part of control information transmitted on PDCCH as shown in the figure. To the UE. As shown in FIG. 2, the UE that has received control information on the PDCCH refers to control information for DMRS antenna port allocation of 230 with reference to 210 corresponding to control information for transport block 0 and 220 corresponding to control information for transport block 1. Determine how you should judge. Information included in 210 corresponding to the control information for Transport block 0 is information regarding whether or not the transport block is transmitted and, if valid, the size of the transport block. Also, the information included in 220 corresponding to the control information for Transport block 1 is information regarding whether or not the transport block is transmitted and, if valid, the size of the transport block. The eNB notifies the UE whether either transport block 0 or transport block 1 is transmitted or two are transmitted together using 210 and 220. The control information for the transport blocks 210 and 220 in FIG. 2 exists from the LTE system, and also exists in the LTE-A system, which is an improved version of the LTE system. In the present invention, as shown by 210 and 220 in FIG. 2, the control information for the transport block and the information on the DMRS resource indicator 230 are linked, and the allocation to the DMRS antenna port is performed using the minimum number of bits.

  Table 1 summarizes the indexes used to notify DMRS antenna port information allocated to UEs according to the present invention and what each index means. Table 1 notifies DMRS antenna port allocation for the following MIMO transmission.

<System characteristics 1>
1. SU-MIMO transmission for 1 to 8 layers 2.1 MU-MIMO transmission for allocating a maximum of 2 layers to 2 UEs 3. MU-MIMO transmission to up to 4 UEs. MU-MIMO transmission for up to 4 layers (MU-MIMO compose rank maximum value 4)

  Table 1 shows not only the function of notifying the DMRS antenna port assigned to the scheduled UE for the eNB transmission as described above, but also the same time and frequency for the UE assigning the DMRS antenna port in the case of MU-MIMO transmission. It is notified which DMRS antenna port is used to signal other UEs that may cause interference in the section.

  According to the present invention, as shown in Table 1, the base station defines different DMRS resource allocation methods using the DMRS resource indicator depending on whether or not the transport block is used.

  Correspondingly, the UE of the present invention has a case where transport block 0 is transmitted among the two transport blocks in Table 1, a case where transport block 1 is transmitted, and transport block 0 and transport block 1 are transmitted. The index transmitted by the eNB is interpreted differently depending on whether it is transmitted together. As an example, the meaning that an eNB corresponds to an index value 3 for a UE is interpreted differently depending on how 210 and 220 in FIG. 2 are set. It is assumed that transport block 0 is not transmitted by 210 of FIG. 2 and only transport block 1 is transmitted by 220 of FIG. In such a case, the UE assigns DMRS antenna port 3 to itself in the rank 4 DMRS pattern corresponding to 110 in FIG. 1, and DMRS antenna ports 0, 1, and 2 use MU-MIMO transmission assigned to other UEs. It is judged that it was performed from eNB. That is, the UE is notified of information regarding the DMRS antenna port assigned to the UE, and at the same time, determines which DMRS antenna port is used to transmit another UE that causes an interference effect to the UE. It becomes possible to perform effective countermeasures against interference.

  When the DMRS antenna port is assigned using Table 1, the information amount of 4 bits as a whole is required. This is because the number of types of indexes that each column of Table 1 has is 10 at maximum. That is, when Table 1 is used, 4-bit DMRS antenna port allocation and interference-related information are loaded in 230 of FIG. 2 and transmitted.

  <SU-MIMO and maximum compose rank 4 for assigning up to 8 layers per UE, and DMRS antenna port in a MU-MIMO (up to 4 co-scheduled UE) transmission scheme for assigning up to 2 layers per UE Interference notification method>

  On the other hand, the DMRS antenna port 0 shown in Table 1 means the first antenna port to which DMRS is assigned in the overall reference signal (Reference Signal, RS), and an arbitrary DMRS antenna port n is the DMRS antenna port 0. The number is incremented sequentially with reference to.

  More specifically, reference signals (Reference Signals, RS) used in LTE and LTE-A systems include common reference signals (Common Reference Signals, CRS), MBMS broadcast reference signals, and dedicated reference signals (Dedicated). Reference Signal (DRS), position reference signal (Positioning Reference Signal, PRS), demodulation reference signal (DeModulation Reference Signal, DMRS), and the like. In this case, antenna ports 0 to 3 are assigned to CRS, antenna port 4 is assigned to the MBMS broadcast reference signal, antenna port 5 is assigned to DRS, and antenna port 6 is assigned to Assigned to PRS, antenna ports 7-14 are assigned to DMRS. The DMRS antenna port 0 of the present invention corresponds to the antenna port 7, and the DMRS antenna port 1 can be interpreted as corresponding to the antenna port 8. The same principle is applied to the following description. Assuming

  FIG. 3 shows which DMRS antenna port is used for transmission to other UEs that may cause interference in the same frequency and time interval at the same time that the eNB assigns the DMRS antenna port to the UE according to the present invention. The eNB notifies the method.

  In step 310 of FIG. 3, the eNB performs scheduling for a specific time and frequency resource. Here, scheduling means a process of determining which UE or UE is allocated a specific time and frequency resource, and determining what data transmission rate is to be transmitted to each UE. In step 310 of FIG. 3, scheduling is performed, and the eNB sets N to the number of UEs that are scheduled together. Here, when the value of N is 1, SU-MIMO transmission is performed, and when it is 2, 3, or 4, MU-MIMO transmission is performed. In step 310 of FIG. 3, after scheduling is completed, the eNB performs an index for DMRS antenna port notification to the j-th UE from step 320. In FIG. 3, a variable j is a variable for distinguishing a UE to be coscheduled, and this value is initialized to 0 in step 320. In step 330, the eNB checks the number of transport blocks allocated to the jth cochedule UE. The number of transport blocks that can be transmitted to one UE that is scheduled is 1 or 2. When one transport block is transmitted to the UE, the transport block can be transmitted in the form of transport block 0 or transport block 1.

  If it is determined in step 330 of FIG. 3 that only transport block 0 is transmitted, the eNB sets an index for notifying DMRS antenna port to be assigned to the j-th UE in step 340 to the first in Table 1. Select from the column. In the first column of Table 1, when only transport block 0 is transmitted to the UE and transport block 1 is not transmitted, a DMRS antenna port is assigned, and if there is another UE in the same time and frequency interval, , Used for notifying which DMRS antenna port the UE uses.

  Also, if it is determined in step 330 of FIG. 3 that only transport block 1 is transmitted, the eNB sets an index for notifying DMRS antenna port to be assigned to the j-th UE in step 350 in Table 1. Select from the second column. The second column of Table 1 shows that if only transport block 1 is transmitted to the UE and transport block 0 is not transmitted, a DMRS antenna port is assigned, and if there is another UE in the same time and frequency interval, and if it exists This is used to notify which DMRS antenna port the UEs use.

  Also, if it is determined in step 330 of FIG. 3 that transport block 0 and transport block 1 are transmitted together, the eNB reports an index for notifying DMRS antenna port assigned to the j-th UE in step 360. Is selected from the third column of Table 1. The third column of Table 1 shows that if transport block 0 and transport block 1 are transmitted to the UE together, DMRS antenna port is assigned, and if there is another UE in the same time and frequency interval, Used to notify what DMRS antenna port the UE uses.

  After the DMRS antenna port allocation index for the jth UE coscheduled in step 340, 350, or 360 of FIG. 3 is determined, in step 370, the DMRS antenna port allocation index for all coscheduled UEs has been determined. Judging. In step 370, if the value of j is N, DMRS antenna port allocation index for all coscheduled UEs is determined. If the DMRS antenna port allocation index for all coscheduled UEs is determined in step 370, the DMRS antenna port allocation index is notified to each UE using the PDCCH as in step 390 of FIG. In addition, when there is a UE for which the DMRS antenna port allocation index is not determined among coscheduled UEs, the DMRS antenna port allocation index is determined from the process 330 for the coscheduled UE.

  FIG. 4 illustrates a case where a UE receives a DMRS antenna port allocation index transmitted by an eNB according to the present invention, determines which DMRS antenna port is allocated to itself, and simultaneously interferes with its received signal at the same frequency and time interval. The method by which the UE determines which DMRS antenna port is used for transmission to other UEs that may be generated.

  In step 405 of FIG. 4, the UE performs PDCCH blind decoding. The blind decoding in step 405 is based on the assumption that transmission was performed in a number of candidate times and frequency intervals because the UE cannot know exactly in which time and frequency interval the PDCCH transmission for itself is performed. Only when decoding is performed with CRC and correct decoding is performed with CRC, the decoded control information is used, so that it is used in the LTE and LTE-A systems.

  In step 405 of FIG. 4, the UE performs blind decoding. In step 410, the UE determines whether a downlink scheduling PDCCH for the UE has been received. If it is determined in step 410 that the downlink scheduling PDCCH for itself has not been received, the UE returns to step 405 to further perform PDCCH blind decoding. When the UE determines that the downlink scheduling PDCCH for itself has been received in step 410, the UE checks the downlink control information (DCI) mounted on the PDCCH as in step 415. As shown in FIG. 2, the Downlink control information is composed of control information about transport block 0, transport block 1, DMRS antenna port allocation control information, and other control information.

  The UE that has confirmed the DCI mounted on the PDCCH in the process 415 of FIG. 4 has transmitted only the transport block 0 in the transport block 0 related control information 210 and the transport block 1 related control information 220 of FIG. 2 or the transport block 0. It is determined whether only 1 has been transmitted, or whether transport block 0 and transport block 1 have been transmitted together. If it is determined in step 420 that only transport block 0 has been transmitted, the UE transmits a message (message) in the first column of Table 1 corresponding to the index indicated by the DMRS antenna port allocation control information 230 in FIG. 2 in step 425. ) To confirm the information regarding the DMRS antenna port allocated. Also, in step 425, the UE confirms information regarding whether or not the MU-MIMO transmission is performed together with other UEs and which DMRS antenna port the UE uses. If it is determined in step 420 that only transport block 1 has been transmitted, the UE transmits a message (message) in the second column of Table 1 corresponding to the index indicated in DMRS antenna port allocation control information 230 in FIG. ) To confirm the information regarding the DMRS antenna port allocated. Also, in step 430, the UE confirms information regarding whether or not the MU-MIMO is performed together with transmission to other UEs and which DMRS antenna port the UE uses. If it is determined in step 420 that transport block 0 and transport block 1 are transmitted together, the UE determines in step 435 the third column of Table 1 corresponding to the index indicated by DMRS antenna port allocation control information 230 in FIG. The information about the allocated DMRS antenna port is confirmed by using the message. Also, in step 425, the UE confirms information regarding whether or not the MU-MIMO transmission is performed together with other UEs and which DMRS antenna port the UE uses.

  In the case of the UE that has confirmed the DMRS antenna port assigned to itself in the process 425 and the process 430 in FIG. 4, only the transmission for one of the transport block 0 or the transport block 1 is received from the eNB. In such a case, the UE estimates a channel for one layer using one allocated DMRS antenna port as in step 440. Also, in the case of the UE that has confirmed the DMRS antenna port assigned to itself in the process 435, the UE receives transmissions for both transport block 0 and transport block 1 from the eNB. In such a case, the UE performs channel estimation for a plurality of corresponding layers using a plurality of allocated DMRS antenna ports as in process 445. In step 450, the UE that has performed channel estimation in steps 440 and 445 determines whether transmission to other UEs is performed in addition to itself in the time and frequency space. That is, in step 450, the UE is a SU-MIMO transmission in which a signal received by itself is transmitted to one UE in the same time and frequency interval, or a MU-MIMO transmission in which transmission is performed to a plurality of UEs. It is judged whether it is. In step 450, whether or not MU-MIMO is available uses the presence / absence of transmission to other UEs notified together with the DMRS antenna port allocation information in steps 425, 430, and 435, and the DMRS antenna port information allocated to other UEs. Can be grasped. If it is determined in step 450 that the transmission is a MU-MIMO transmission, the UE detects a signal mounted on a DMRS antenna port assigned to another UE other than itself in step 455 and receives the received signal. Use to improve signal performance. In step 455, one method for improving the performance of the received signal is to measure the signal strength of the DMRS allocated to other UEs and utilize the signal strength for a MMSE (Minimum Mean Square Estimator) receiver. Another method is to use an interference cancellation receiver using the DMRS antenna port, which is assigned to another UE, and then used to determine the DMRS antenna port. If it is determined in step 450 that the transmission is a non-MU-MIMO SU-MIMO transmission, the UE does not transmit to another UE using the same time and frequency resources as the UE. The received signal is processed as in step 460 using the SU-MIMO reception method.

  The UE that has completed the reception operation in the process 455 or the process 460 of FIG. 4 resumes PDCCHblind decoding in the process 405.

  Table 1 is used to support SU-MIMO and MU-MIMO having characteristics such as <System characteristic 1> described above. In the LTE-A system, the eNB can actually perform transmission using SU-MIMO and MU-MIMO in a form different from <system characteristic 1>. Table 2 is used to support SU-MIMO and MU-MIMO having the following characteristics <system characteristic 2> according to the present invention.

<System characteristics 2>
1. SU-MIMO transmission for 1 to 8 layers 2.1 MU-MIMO transmission for allocating a maximum of 2 layers to 2 UEs 3. MU-MIMO transmission to up to 2 UEs MU-MIMO transmission for up to 4 layers (MU-MIMO compose rank maximum value 4)

  When coscheduling for up to two UEs at the same time as in system characteristic 2, the number of DMRS antenna port assignments and interference related information that need to be notified is relatively reduced as compared with Table 1. This decrease in the number of cases can be seen by comparing the first and second columns of Table 2 with the first and second columns of Table 1.

  When assigning DMRS antenna port using Table 2, the total amount of information of 4 bits is required. This is because each column in Table 2 has a maximum of 10 types of indexes. That is, when Table 2 is used, 4-bit DMRS antenna port allocation and interference-related information are mounted in 230 of FIG. 2 and transmitted.

  <SU-MIMO and maximum compose rank 4 for assigning a maximum of 8 layers per UE, and DMRS antenna port in a MU-MIMO (maximum 2 co-scheduled UE) transmission scheme for assigning a maximum of 2 layers per UE Interference notification method>

  The method by which the eNB determines the DMRS antenna port allocation index using Table 2 is the same as the case of FIG. Also, the method in which the UE receives the DMRS antenna port assignment index and interprets it is the same as in the case of FIG.

  Table 3 summarizes the indexes used to notify DMRS antenna port information assigned to UEs according to the present invention and the meaning of each index. Table 3 reports DMRS antenna port allocation for MIMO transmission such as <System Characteristics 1>. Table 3 differs from Table 1 in the method of partitioning DMRS signals according to DMRS pattern and DMRS antenna port used when transmitting DMRS signals. Specifically, in Table 3, as described below, a DMRS signal is classified according to DMRS pattern and each DMRS antenna port using a scrambling sequence.

  In FIG. 1 described above, when the number of layers transmitted in the MU-MIMO transmission is 3 or 4, the eNB may divide the DMRS signal divided into the frequency domain and code division into each DMRS antenna as indicated by 110 in FIG. assigned to port. That is, DMRS antenna port 0 is transmitted in Walsh code 0 (+1, +1) with a length of 2 in the blue RE region, while DMRS antenna port 3 is Walshcode No. 1 (2 in the red RE region with a length of 2). +1, -1). Table 1 corresponds to the case where the DMRS signal of each DMRS antenna port is divided in this way when the number of layers transmitted by MU-MIMO transmission is 3 or 4.

  When the number of layers transmitted in the MU-MIMO transmission is 3 or 4, another method for dividing the DMRS antenna port is a method using two scrambling sequences. That is, when the number of layers transmitted in the MU-MIMO transmission is 3 or 4, an additional red RE region is allocated to the blue RE region without assigning an additional RE for DMRS transmission as illustrated in 110 of FIG. In this case, transmission to up to four DMRS antenna ports is performed by MU-MIMO transmission using an additional scramble sequence. Such a method is consequently the same as using both rank 2 DMRS pattern, using two scrambled sequences, and defining both DMRS antenna port 0 and DMRS antenna port 1 per scrambled sequence. . That is, when the number of layers transmitted using MU-MIMO is 3 or 4, the DMRS antenna port is classified as follows.

1. DMRS antenna port0 that uses Walsh code 0 using Scrambling sequence 0 (SC0)
2. DMRS antenna port 1 using Walsh code 1 using Scrambling sequence 0 (SC0)
3. DMRS antenna port0 using Walsh code 0 using Scrambling sequence 1 (SC1)
4). DMRS antenna port1 using Walsh code 1 using Scrambling sequence 1 (SC1)

  When the number of layers transmitted using the MU-MIMO is 3 or 4, DMRS antenna port 0 and DMRS antenna port 1 are provided for each scrambled sequence using a method of dividing the DMRS antenna port. In addition to such a method, the above four different cases may be named DMRS antenna port 0, DMRS antenna port 1, DMRS antenna port 2, DMRS antenna port 3, respectively. Can be obtained.

  FIG. 5 is a diagram illustrating using two scrambled sequences with the same time and frequency resources in order to distinguish DMRS antenna ports when the number of layers transmitted in MU-MIMO transmission is 3 or 4. . In FIG. 5, it can be seen that DMRSs for four DMRS antenna ports are transmitted using two scrambled sequences in the same RE region.

  Table 3 shows DMRS antenna port information allocated to the UE according to the present invention when DMRS pattern using two scrambling sequences is utilized when transmitting composite rank 3 or 4 in MU-MIMO as described above. This is a summary of the indexes used for notification and the meaning of each index. In Table 3, SC is an abbreviation for scrambling sequence, and it is assumed that the scrambling sequence is always 0 in the case of SU-MIMO transmission.

  The index used to notify DMRS antenna port information assigned to the UE in Table 3 according to the present invention and the meaning of each index are basically the same as Table 1. One difference is that in Table 1, when composite rank is 3 or 4 without SU-MIMO and MU-MIMO partitioning, DMRS antenna port signals are partitioned in a manner like 110 in FIG. In the case of MU-MIMO in Table 3, when the composite rank is 3 or 4, an additional scramble sequence is used, and only in the case of SU-MIMO, the DMRS antenna port signal is transmitted in a manner as shown in FIG. It is to categorize.

  The method by which the eNB determines the DMRS antenna port allocation index using Table 3 is the same as the case of FIG. Also, the method in which the UE receives the DMRS antenna port assignment index and interprets it is the same as in the case of FIG.

  <SU-MIMO and maximum compose rank 4 for assigning up to 8 layers per UE, and DMRS antenna port in a MU-MIMO (up to 4 co-scheduled UE) transmission scheme for assigning up to 2 layers per UE Interference notification method 2>

  In the case of Table 3, when composite ranks 3 and 4 are transmitted by MU-MIMO transmission, this corresponds to a case where signals for four DMRS antenna ports are distinguished by additionally using a scrambling sequence in the rank 2 DMRS pattern. In such a case, another method of distinguishing signals for four DMRS antenna ports is to use a length-4 orthogonal code for frequency and time resources corresponding to rank 2 DMRS pattern. That is, when transmitting composite ranks 3 and 4 by MU-MIMO transmission, DMRS is transmitted by assigning one orthogonal code of length 4 to each rank 2 DMRS pattern and one DMRS antenna port. Such cases can also be defined as shown in Tables 1 and 3.

  When the DMRS antenna port is allocated using Table 3, the total amount of information of 4 bits is required. This is because the maximum number of index types that each column of Table 3 has is 10. That is, when Table 3 is used, 4-bit DMRS antenna port allocation and interference-related information are mounted in 230 of FIG. 2 and transmitted.

  In Tables 1, 2, and 3, this corresponds to a case where the eNB notifies the UE of whether it is SU-MIMO or MU-MIMO together with DMRS antenna port allocation. In the present invention, in addition to the above method, the eNB performs transmission among SU-MIMO or MU-MIMO while performing DMRS antenna port allocation and interference notification effectively in LTE-A. A method for notification is also presented.

  FIG. 6 shows another 1-bit control information “SU / MU-MIMO Indicator” for distinguishing whether transmission of eNB is SU-MIMO or MU-MIMO transmission according to the present invention, and DMRS antenna transmitted in association therewith. The port allocation control information is illustrated.

  When using the SU / MU-MIMO Indicator according to the present invention, the eNB notifies the scheduled UE with the value of the SU / MU-MIMO Indicator set to “0” when its transmission is SU-MIMO transmission. Also, when the own transmission is MU-MIMO transmission, the eNB notifies the cochedled UE with the value of the SU / MU-MIMO Indicator set to “1”. According to the present invention, when the SU / MU-MIMO indicator is used and the value of the SU / MU-MIMO indicator is “0”, that is, the number of layers transmitted by the eNB indicating SU-MIMO is 1, only transport block 0 is always used. Is transmitted. This is SU-MIMO. When the number of layers transmitted by the eNB is 1, only one transport block can be transmitted, and the amount of control information for DMRS antenna port allocation is reduced. Therefore, a transport block that is always fixed according to the present invention is transmitted. Also, in case of SU-MIMO and the number of layers transmitted by the eNB is one of 2, 3, 4, 5, 6, 7, and 8, only two transport blocks can be transmitted. This is because a transport block 0 that is always fixed by the present invention is transmitted in order to reduce the amount of control information for DMRS antenna port allocation.

  When using the SU / MU-MIMO Indicator according to the present invention, two tables are used according to the value of the SU / MU-MIMO Indicator in order for the eNB and the UE to transmit and receive information regarding DMRS antenna port allocation and interference. To come.

  Table 4 indicates that the index and each index used to notify DMRS antenna port information allocated to the UE according to the present invention when the transmission of the eNB is SU-MIMO using the SU / MU-MIMO Indicator. It is an arrangement of things. In the case of Table 4, it is composed of two columns. Compared with Tables 1, 2, and 3, transport block 0 is not transmitted, and it is understood that there is no column corresponding to transport block 1 being transmitted. In the case of Table 4, since only DMRS antenna port allocation information for SU-MIMO is included and not MU-MIMO transmission, information related to interference is not included.

  Table 5 shows the index and each index used to notify DMRS antenna port information allocated to the UE according to the present invention when the transmission of the eNB is MU-MIMO using the SU / MU-MIMO Indicator. It is an arrangement of things. In the case of Table 5, in addition to information for DMRS antenna port allocation for each index, information on interference signals is also included.

  Tables 4 and 5 were devised in accordance with the above <System characteristics 1>.

<When using the SU / MU-MIMO indicator, DMRS antenna port and interference notification method (for SU-MIMO)>

  <When RS / MU-MIMO Indicator is used, DMRS antenna port and interference notification method (for MU-MIMO)>

  When assigning DMRS antenna port using Table 4, the total amount of information of 4 bits is required. This is because the maximum number of index types that each column of Table 4 has is 5, and 1 bit is required to transmit the SU / MU-MIMO Indicator. That is, when Table 4 is used, a 1-bit SU / MU-MIMO Indicator, a 3-bit DMRS antenna port allocation, and interference-related information are mounted and transmitted in 630 of FIG.

  FIG. 7 shows that when the SU / MU-MIMO indicator is used according to the present invention, the eNB assigns the DMRS antenna port to the UE, and at the same time, transmission to other UEs that may cause interference in the same frequency and time interval. The figure shows how the eNB notifies which DMRS antenna port is used.

  In step 705 of FIG. 7, the eNB performs scheduling for the specific time and frequency resource. Here, scheduling refers to a process of determining which UE or UE is allocated a specific time and frequency resource, and determining what data transmission speed is to be transmitted to each UE. Scheduling is performed in step 705 of FIG. 7, and the eNB sets the number of coscheduled UEs to N.

  In step 710, the eNB determines whether the transmission scheme determined by scheduling is SU-MIMO transmission or MU-MIMO transmission. If the value of N determined in step 705 is 1, it corresponds to SU-MIMO, and if the value of N is greater than 1, it corresponds to MU-MIMO. If the value of N is 1 in step 710 (SU-MIMO), the eNB sets the value of the SU / MU-MIMO indicator to “0” in step 715. After the value of the SU / MU-MIMO indicator is set in step 715, the eNB assigns the scheduled UE as in step 725 when the transport block transmitted to the SU-MIMO is one. The index for notifying the DMRS antenna port is selected from the first column of Table 4. When there are two transport blocks transmitted in SU-MIMO, the eNB selects an index for notifying the DMRS antenna port to be assigned to the scheduled UE from the second column of Table 4 as in step 730. . In Step 725 or Step 730, the eNB determines an index for notifying the UE of DMRS antenna port allocation, and then transmits this information and the SU / MU-MIMO Indicator together with other control information on the PDCCH. In step 735, since the transmission method of the eNB is SU-MIMO, the value of the SU / MU-MIMO indicator becomes “0”.

  If the value of N is larger than 1 in step 710 of FIG. 7 (MU-MIMO), the eNB sets the value of the SU / MU-MIMO indicator to “1” in step 740. After the value of the SU / MU-MIMO indicator is set in the process 740, the operation process of the eNB is the same as that after the process 320 in FIG. 3, and a description thereof will be omitted. One difference from the process 320 onward in FIG. 3 is that the PDCCH transmitted to each UE is transmitted with the SU / MU-MIMO indicator set to “1” in the process 780 of FIG. In the case of the process 390 in FIG. 3, the SU / MU-MIMO Indicator is not used, and thus this value is not transmitted.

  FIG. 8 shows that when the SU / MU-MIMO Indicator is used according to the present invention, the UE receives the DMRS antenna port assignment index transmitted by the eNB, and simultaneously determines what DMRS antenna port is assigned to the UE, and at the same frequency. 4 illustrates a method in which a UE determines which DMRS antenna port is used for transmission to another UE that may cause interference in its received signal in a time interval.

  In step 805 of FIG. 8, the UE performs PDCCH blind decoding. The blind decoding in step 805 is based on the assumption that the transmission occurred in a number of candidate times and frequency intervals, since the UE does not know exactly in which time and frequency interval the PDCCH transmission for itself is performed. Only when decoding is performed and correct decoding is performed by CRC, the decoded control information is used, and is used in the LTE and LTE-A systems.

  In step 805 of FIG. 8, the UE performs blind decoding. In step 810, the UE determines whether a downlink scheduling PDCCH for the UE has been received. If it is determined in step 810 that the downlink scheduling PDCCH for the UE has not been received, the UE returns to step 805 and further performs PDCCH blind decoding. When the UE determines that the downlink scheduling PDCCH for the UE has been received in Step 810, the UE checks the downlink control information (DCI) installed in the PDCCH as in Step 815. As shown in FIG. 6, the Downlink control information includes control information for transport block 0, transport block 1, SU / MU-MIMO indicator, DMRS antenna port allocation control information, and other control information.

  In step 820, the UE confirms whether SU / MU-MIMO Indicator is set to “0” or “1” in the control information mounted on the PDCCH. When the SU / MU-MIMO indicator is “0”, this corresponds to SU-MIMO, and the UE transmits only transport block 0 or both transport block 0 and transport block 1 in step 825. Determine whether. If it is determined in step 825 that the UE has received only transport block 0 from the eNB, the UE determines in step 830 the first of Table 4 corresponding to the index indicated by the DMRS antenna port allocation control information 640 of FIG. Check the information about DMRS antenna port assigned through the column message. Information about DMRS antenna port obtained in step 830 is used to perform channel estimation in step 835. In step 835, the UE performs channel estimation for one layer transmitted by using the allocated DMRS antenna port, and in step 840, the UE processes the received signal using the SU-MIMO reception method. The reason why the SU-MIMO reception method is used in the process 840 is that the above-described SU / MU-MIMO Indicator has a value of “0”. If the UE determines that both transport block 0 and transport block 1 were transmitted in step 825, in step 845, the message in the second column of Table 4 corresponding to the index indicated by the DMRS antenna port allocation control information 640 of FIG. Confirm the information about DMRS antenna port assigned through. Information regarding DMRS antenna port obtained in step 845 is used to perform channel estimation in step 850. In step 850, the UE performs channel estimation for a plurality of layers transmitted by itself using the allocated DMRS antenna port. In step 850, the UE processes the received signal using the SU-MIMO reception method. This is also because the SU / MU-MIMO indicator has a value of “0” as described above.

  In step 820, if the SU / MU-MIMO Indicator is set to “1” among the control information mounted on the PDCCH, the UE transmits only transport block 0 to itself in step 855. It is determined whether the eNB transmitted only transport block 1 to itself, or whether the eNB transmitted both transport block 0 and transport block 1 to itself. If the UE determines that only transport block 0 was transmitted in step 855, it is assigned through the message in the first column of Table 5 corresponding to the index indicated by the DMRS antenna port assignment control information 640 of FIG. 6 in step 860. Information about the received DMRS antenna port and interference. The UE performs channel estimation for one layer using the DMRS antenna port allocated in step 865 using the DMRS antenna port information allocated in step 860. Next, in step 870, the UE detects a signal mounted on another DMRS antenna port based on the determination that the received signal is part of the MU-MIMO transmission, and improves the performance of the received signal. Use it to make it happen.

  If the UE determines that only transport block 1 has been transmitted by itself in step 855, the message of the second column of Table 5 corresponding to the index indicated by the DMRS antenna port allocation control information 640 of FIG. Confirm information about the assigned DMRS antenna port and interference. The UE performs channel estimation for one layer using the DMRS antenna port assigned in step 865 using the DMRS antenna port information assigned in step 875. Next, in step 870, the UE detects a signal mounted on another DMRS antenna port based on the determination that the received signal is part of the MU-MIMO transmission, and improves the performance of the received signal. Use it to make it happen.

  If the UE determines that both transport block 0 and transport block 1 are transmitted by the UE in the process 855, the third RS in Table 5 corresponding to the index indicated by the DMRS antenna port allocation control information 640 in FIG. Check the DMRS antenna port assigned through the message of the column and the information about the interference. The UE performs channel estimation for a plurality of layers using the DMRS antenna port allocated in step 885 using the allocated DMRS antenna port information obtained in step 880. Next, in step 870, the UE detects a signal mounted on another DMRS antenna port based on the determination that the received signal is part of the MU-MIMO transmission, and improves the performance of the received signal. Use it to make it happen.

  The UE that has completed the reception operation in the process 840 or the process 870 of FIG. 8 resumes PDCCHblind decoding in the process 805.

  In the case of Tables 1, 2, 3, 4, and 5 described above, not only information on DMRS antenna ports allocated to UEs to which the eNB is scheduled, but also whether the transmission is SU-MIMO transmission or MU-MIMO transmission. In the case of cognitive and MU-MIMO transmission, information on DMRS antenna port assigned to other UEs that may cause interference is also notified. In this way, notifying the scheduled UE of the DMRS antenna port assigned to another UE enables accurate interference measurement by the UE, and consequently improves reception performance. Disadvantageous information must be transmitted.

  Accordingly, the present invention also provides a method that does not provide information regarding interference in a method of assigning DMRS antenna port depending on whether transport block 0 and transport block 1 are assigned to one UE. Such a method is effective in reducing the amount of control information for DMRS antenna port allocation by not providing information on interference.

  Table 6 summarizes the indexes used to notify DMRS antenna port information assigned to UEs according to the present invention and the meaning of each index. Unlike Tables 1, 2, 3, 4, and 5, Table 6 was created so that the eNB can only notify information related to the DMRS antenna port assigned to the UE. Therefore, when Table 6 is used, the eNB cannot provide additional information on interference to the UE even when performing MU-MIMO transmission.

  Table 6 was devised according to the above <System characteristic 1>, and was created under the assumption that the rank 4 DMRS pattern is used when the composite rank is 3 or 4.

  Since the method of notifying the DMRS assigned to the UE by the eNB using Table 6 is the same as in FIG. 3, detailed description thereof is omitted. The difference between using the method of FIG. 3 and Table 6 is that there is no additional consideration for interference when the eNB notifies the UE.

  In Table 6, each column has 9 types of indexes. In the case of Table 1, the number of types of indexes that each column has was 10 at maximum. In Table 6, the decrease in the types of indexes included in each column means that it is no longer necessary to transmit information on interference, and the amount of information to be transmitted is reduced.

  <Su-MIMO and maximum compose rank 4 for assigning up to 8 layers per UE, and DMRS antenna port notification in a MU-MIMO (up to 4 co-scheduled UE) transmission method for assigning up to 2 layers per UE Method 1>

  Table 7 below summarizes the indexes used to notify DMRS antenna port information assigned to UEs according to other embodiments of the present invention and the meaning of each index. Table 7 was created so that the eNB notifies only the information regarding the DMRS antenna port assigned to the UE, unlike the cases of Tables 1, 2, 3, 4, and 5. Therefore, when using Table 7, even if eNB performs MU-MIMO transmission, it cannot provide separate information on interference to the UE.

  Table 7 was devised in accordance with <System Information 1>, and was created under the assumption that when the rank rank is 3 or 4, rank 2 DMRS pattern and two scramble sequences are used. This is the same as in Table 3.

  Since the method in which the eNB notifies the DMRS assigned to the UE using Table 7 is similar to that in FIG. 3, detailed description thereof is omitted. The difference between using the method of FIG. 3 and Table 7 is that there is no additional consideration for interference when the eNB notifies the UE.

  In Table 7, each column has 8 types of indexes. In the case of Table 1, the number of types of indexes that each column has was 10 at maximum. In Table 7, the decrease in the types of indexes included in each column means that it is not necessary to transmit information on interference, and the amount of information to be transmitted is reduced. When this is converted into the number of bits, in the case of Table 1, 4 bits are required to notify the UE of the DMRS antenna port allocation information and the interference related information. However, when using Table 7, the eNB uses the DMRS antenna port. Only 3 bits are required to inform the UE of the allocation information.

  <Su-MIMO and maximum compose rank 4 for assigning up to 8 layers per UE, and DMRS antenna port notification in a MU-MIMO (up to 4 co-scheduled UE) transmission method for assigning up to 2 layers per UE Method 2>

  In the case of Table 1 to Table 7, when the eNB performs automatic complex retransmission (HARQ), it is applied only when DMRS antenna port allocation is performed for initial transmission.

  On the other hand, when retransmission is performed in performing automatic complex retransmission, notification for cases other than DMRS antenna port assignments that can be specified in Tables 1 to 7 must be performed.

  When automatic combined retransmission is applied, the difference between retransmission and initial transmission is as follows. In the case of initial transmission, if one transport block is transmitted, transmission is performed by one layer. In the case of retransmission, even if one transport block is transmitted, it can be transmitted to a plurality of layers at the eNB's discretion. In order to inform the UE of the DM-RS antenna port assignment for the retransmission case in this way, the present invention proposes two methods. The first method is to define additional allocation information for indexes that are not used in Tables 1, 2, 3, 4, 5, 6, and 7 that are used for allocating DM-RS antenna ports.

  Table 8 is devised in accordance with <System Information 1>, and is created under the assumption that rank 2 DMRS pattern and two scrambled sequences are used when compose rank is 3 or 4, as in Table 7. It was done. Table 8 was created so that the eNB notifies only the information on the DMRS antenna port assigned to the UE, unlike the cases of Tables 1, 2, 3, 4, and 5. Therefore, when Table 8 is used, the eNB cannot provide additional information on interference to the UE even when performing MU-MIMO transmission.

  Table 8 has the following differences when compared with Table 7.

  1. Even if only one of transport block 0 or transport block 1 is transmitted to the UE, it can be freely assigned among the combinations of four types of DMRS antenna port and scramble code. That is, when one transport block is transmitted to the UE, DM-RS antenna port 0 and scramble sequence 0, DM-RS antenna port 1 and scramble sequence 0, DM-RS antenna 1 and DM-RS antenna port 1 and DM-RS antenna 1 One of the scrambling sequences 1 can be freely assigned. Indexes 0, 1, 2, and 3 in the first and second columns in Table 8 correspond to this.

2. An index has been defined for additional DM-RS antenna port allocation that can only be applied in case of retransmissions. This corresponds to the indexes 4, 5, 6, and 7 in the first and second columns of Table 8.

  <Su-MIMO and maximum compose rank 4 for assigning up to 8 layers per UE, and DMRS antenna port notification in a MU-MIMO (up to 4 co-scheduled UE) transmission method for assigning up to 2 layers per UE Method 3>

  In Table 8, the maximum number of index types that each column has is eight. In the case of Table 1, the number of types of indexes that each column has was 10 at maximum. In Table 8, each column has 8 indexes regardless of the number of transport blocks to be allocated. Therefore, when allocating DMRS antenna port using Table 8, 3 bits are required. Although Table 8 can perform all DM-RS antenna port assignments for initial transmission and retransmission by automatic combined retransmission in comparison with Table 7, the required number of bits is 3 as in Table 7.

  In Table 8, DM-RS antenna port allocation information corresponding to indexes 4, 5, 6, and 7 in the first and second columns is transmitted only when one transport block is transmitted and the transport block is retransmitted. It is valid. On the other hand, in Table 8, DM-RS antenna port allocation information corresponding to indexes 4, 5, 6, and 7 in the first and second columns is valid for initial transmission and retransmission.

  In Table 8, the first column and the second column are the same. Therefore, Table 8 can be expressed as in Table 9 below. In the case of Table 9, the first column and the second column of Table 8 are combined into one column, but as a result, they have the same meaning. On the other hand, the indexes shown in Table 9 below are merely examples, and all the indexes must not be used indispensably. It should be noted that an arbitrary index may be omitted and used according to a channel condition between a base station and a terminal and an implementation method.

  <Su-MIMO and maximum compose rank 4 for assigning up to 8 layers per UE, and DMRS antenna port notification in a MU-MIMO (up to 4 co-scheduled UE) transmission method for assigning up to 2 layers per UE Method 3>

  As shown in Table 9, when the number of transmission blocks is 1, the rank is 4 at maximum, and when the rank is 1 or 2, the scrambling sequence is: If it is 0 or 1 and the rank is 3 or more, it can be seen that the scrambling sequence is 0. Similarly, when the number of transmission blocks is 2, the rank is a maximum of 8, and when the rank is 1 or 2, the scrambling sequence is 0 or 1, and the rank is When the number is 3 or more, the scrambling sequence is 0.

  In Table 9, the number of transmission blocks is 1, and in the case of initial transmission, the DMRS antenna port assignment instruction information is interpreted only for rank 1. Also, the number of transmission blocks is one, and in the case of retransmission, the DMRS antenna port assignment instruction information is interpreted for all ranks. When the number of transmission blocks is two, the DMRS antenna port assignment instruction information is interpreted for all ranks for initial transmission or retransmission.

  FIG. 9 illustrates a method in which the eNB allocates the DM-RS antenna port using Table 8. To summarize the operation of the eNB, a confirmation stage for confirming the number of transmission blocks allocated to a terminal, a selection stage for selecting DMRS (DeModulation Reference Signal) antenna port allocation instruction information according to the number of transmission blocks confirmed, and Generating a control information including information related to at least one transport block and the selected DMRS (DeModulation Reference Signal) antenna port allocation instruction information; and The method includes a transmission stage for transmission to the terminal, which will be described in detail as follows.

  In step 900 of FIG. 9, the eNB performs scheduling of a specific subframe. The index is selected differently in Table 8 depending on whether one transport block is transmitted to the terminal scheduled in the process 900 or two transport blocks are allocated. That is, when transmitting 2 transport blocks to the terminal, the eNB selects an index corresponding to the DM-RS antenna port allocation information from the third column of Table 8 as in Step 950. When transmitting two transport blocks to a terminal, the DM-RS antenna port assignment from the third column of Table 8 is performed regardless of whether the transport block to be transmitted is transmitted for the first time or retransmitted. An index corresponding to information is selected.

  In FIG. 9, when the eNB transmits one transport block to the UE, the eNB selects an index differently in Table 8 depending on whether the transport block is transmitted for the first time or retransmitted. In the case of initial transmission, the eNB selects one index excluding indexes 4, 5, 6, and 7 in the first and second columns and determines DM-RS antenna port allocation information as in step 940. To do. On the other hand, in the case of retransmission, the eNB selects one index from the indexes of the first and second columns as in step 930, and determines DM-RS antenna port allocation information.

  FIG. 10 illustrates a method in which the terminal interprets the DM-RS antenna port when the eNB allocates the DM-RS antenna port using Table 8. Summarizing the operation procedure of the terminal, the reception step of receiving control information including information on at least one transport block and DMRS (DeModulation Reference Signal) antenna port assignment instruction information from the base station; A confirmation step of confirming the number of transmission blocks allocated to the terminal using control information, and an interpretation step of interpreting the DMRS antenna port assignment instruction information according to the number of transmission blocks. The specific process is as follows.

  In step 1000 of FIG. 10, blind decoding is performed on the PDCCH. If it is determined in step 1010 that the PDCCH for the terminal has been received, the terminal checks DCI mounted on the PDCCH in step 1020. If it is determined in step 1020 that one transport block has been allocated as a result of checking the DCI, the terminal determines whether the transmission is an initial transmission or a retransmission in step 1040. If it is determined in step 1040 that it is a retransmission, the UE uses the indexes of the first and second columns of Table 8 and corresponding DM-RS antenna port allocation information in step 1050. Check the DM-RS antenna port assigned to you. Also, if it is determined in step 1040 that the transmission is an initial transmission, the terminal corresponds to the index excluding the 4, 5, 6, and 7 indexes in the first and second columns of Table 8 in step 1060 and corresponding to this. The DM-RS antenna port assigned to the user is confirmed using the DM-RS antenna port assignment information.

  If the terminal is assigned two transport blocks in step 1030 of FIG. 10, the terminal assigns the index in the third column of Table 8 and the corresponding DM-RS antenna port assignment information as shown in step 1070. To confirm the DM-RS antenna port assigned to the user. When two transport blocks are allocated, it is possible to determine what DM-RS antenna port is allocated without determining whether or not retransmission is possible.

  In FIG. 9 and FIG. 10, one example of a method for determining whether the transmission is an initial transmission or a retransmission is to refer to an NDI (New Data Indicator) bit in control information transmitted by the eNB. It can be judged by doing. The value of the NDI bit changes when a new initial transmission occurs. That is, the value of the NDI bit was “0” in the nth transmission, but the value of the NDI bit is changed to “1” in the initial transmission in the (n + 1) th transmission. On the other hand, in the case of retransmission, the value of the NDI bit is maintained as it is.

  Tables 8 and 9 can notify the terminal of DM-RS antenna port allocation information in initial transmission and retransmission using one table. Another way to represent Table 8 and Table 9 is to separate the initial transmission table and the retransmission table. As an example, in the case of Table 9, in the case of initial transmission, the following Table 10 and Table 11 can be separated.

  <Su-MIMO and maximum compose rank 4 for assigning up to 8 layers per UE, and DMRS antenna port notification in a MU-MIMO (up to 4 co-scheduled UE) transmission method for assigning up to 2 layers per UE Method 3 (for initial transmission)>

  <Su-MIMO and maximum compose rank 4 for assigning up to 8 layers per UE, and DMRS antenna port notification in a MU-MIMO (up to 4 co-scheduled UE) transmission method for assigning up to 2 layers per UE Method 3 (for retransmission)>

  Tables 8, 9, 10, and 11 are devised in accordance with the above <System Information 1>, and are created under the assumption that rank 2 DMRS pattern and two scrambled sequences are used when compose rank is 3 or 4. It was done. When the rank 4 DMRS pattern is used when the composition rank is 3 or 4 and has the same system information 1 feature, it is used to notify DM-RS antenna port information as shown in Table 12 below. Index and what each index means.

  <Su-MIMO and maximum compose rank 4 for assigning up to 8 layers per UE, and DMRS antenna port notification in a MU-MIMO (up to 4 co-scheduled UE) transmission method for assigning up to 2 layers per UE Method 4>

  In the case of Table 12, the indexes 6, 7, 8, 9 in the first column and the second column and the DM-RS antenna port allocation message corresponding thereto are used only for retransmission. That is, in the case of initial transmission, the DM-RS antenna port allocation is notified only by the index excluding indexes 6, 7, 8, and 9 in the first column and the second column and the corresponding message.

  In the case of Table 12, similarly to Table 8, it can be represented by a table having two columns as in Table 9, and also as Tables 10 and 11, a table for initial transmission and retransmission. Can be expressed in

  Also in the case of Table 12, as in the case of Table 8, the DM-RS antenna port allocation information to be transmitted by the eNB is determined using the same method as in FIGS. 9 and 10, and the DM received by the terminal -Interpret RS information.

  Table 13 summarizes the indexes used to notify DMRS antenna port information assigned to UEs according to the present invention and the meaning of each index. Table 13 differs from Tables 1, 2, 3, 4, 5, 6, and 7 in that when the eNB assigns only one transport block assigned to the UE, DMRS antenna port assignment information for this is shown. Created to notify interference related information. Table 8 informs DMRS antenna port allocation for the following MIMO transmission.

<System characteristics 3>
1. SU-MIMO transmission for one layer 2.1 MU-MIMO transmission for assigning a maximum of one layer to one UE 3. MU-MIMO transmission to up to 4 UEs. MU-MIMO transmission for up to 4 layers (MU-MIMO compose rank maximum value 4)

  <Maximum composite rank 4 and DMRS antenna port and interference notification method 1 in SU and MU-MIMO transmission scheme for transmitting one transport block per UE>

  In Table 13, the maximum number of index types that each column has is six. In the case of Table 1, the number of types of indexes that each column has was 10 at maximum. In Table 13, the number of types of indexes in each column is reduced because the number of transport blocks that can be allocated per UE is limited to one, thereby reducing the number of cases. When this is converted into the number of bits, in the case of Table 1, 4 bits are required to notify the UE of the DMRS antenna port allocation information and the interference related information. However, when using Table 13, the eNB uses the DMRS antenna port. Only 3 bits are required to notify the UE of allocation information and interference related information.

  Table 14 below summarizes the indexes used to notify DMRS antenna port information assigned to UEs according to other embodiments of the present invention and the meaning of each index. Table 14 is different from Tables 1, 2, 3, 4, 5, 6, and 7, when the eNB assigns only one transport block assigned to the UE, DMRS antenna port assignment information for this is assigned. Created to notify and interference related information. Table 1 reports DMRS antenna port assignments for MIMO transmissions such as system characteristic 3. In addition, when compose rank is 3 or 4, it was created under the assumption that rank 2 DMRS pattern and two scrambling sequences are used. This is the same as in Table 3.

  In Table 14, the maximum number of index types that each column has is six. In the case of Table 1, the number of types of indexes that each column has was 10 at maximum. In Table 14, the number of types of indexes in each column is reduced because the number of transport blocks that can be allocated per UE is limited to one, thereby reducing the number of cases. When this is converted into the number of bits, in the case of Table 1, 4 bits are required to notify the UE of DMRS antenna port allocation information and interference related information. When using Table 14, only 3 bits are required for the eNB to notify the UE of DMRS antenna port allocation information and interference related information.

  <Maximum composite rank 4 and DMRS antenna port and interference notification method 2 in SU and MU-MIMO transmission scheme for transmitting one transport block per UE>

  The specific DMRS antenna port is referred to in the DMRS antenna port allocation method. As an example, when transmission block 0 and transmission block 1 are used at the same time in Table 7, Index 5 uses scrambling code No. 0 and DMRS antenna port 0, 1, 2, 3, 4, 5 is assigned. Means that. It will be apparent that the present invention can be equally applied to other union assignments besides the specific DMRS antenna port combinations mentioned in the table. As an example, when the transmission block 0 and the transmission block 1 are used at the same time in Table 7, the method presented in the present invention is that the index 5 uses the scrambling code number 0 and the DMRS antenna port 0, 1, 2, 3 The same can be applied to the case where DMRS antenna ports 0, 1, 2, 5, 6, 7 are assigned instead of 4, 5 being assigned.

  FIG. 11 illustrates DMRS antenna port allocation information transmitted on PDCCH in LTE-A according to another embodiment of the present invention.

  In FIG. 11, the transmitted PDCCH control information is the same as the control information transmitted in FIG. 2, but the control information for each transport block is separated into NDI (New Data Indicator) bits and other information. . In FIG. 11, control information 1110 and 1120 is control information for transport block 0, and control information 1130 and 1140 is control information for transport block 1. The NDI control information 1120 and 1140 are control information for notifying whether transport block 0 and transport block 1 correspond to initial transmission in the process of HARQ (Hybrid Automatic Repeat Request), respectively. The NDI bit indicates whether the transmission is HARQ initial transmission or retransmission only when each transport block is transmitted. That is, when transport block 0 is not transmitted, the NDI 0 bit can be used for other purposes without needing to notify whether it is an initial transmission of HARQ or a retransmission.

  Table 15 summarizes the DM-RS port and the method of instructing the transmission method using the NDI bit for transport block that is not transmitted according to the present invention.

  <SU-MIMO and maximum compose rank 4 for assigning up to 8 layers per UE, and DMRS antenna port in a MU-MIMO (up to 4 co-scheduled UE) transmission scheme for assigning up to 2 layers per UE Transmit diversity notification method>

  In Table 15, “NDI x” is an NDI bit for transport block that is not transmitted, and can be used to notify a terminal of a transmission scheme of one transport block. In the case of Table 1 to Table 14, only SU-MIMO or MU-MIMO could be notified to the terminal. On the other hand, in Table 15, when only one transport block is transmitted, an NDI bit for transport block that is not transmitted is additionally used to notify the terminal of the availability of transmission diversity. The transmission diversity corresponds to the case where CRS (Common Reference Signal) is used, and only SFBC (Space Frequency Block Code) is used depending on how many antenna ports the CRS has, or FSTD (v Demand Trans Code). And SFBC can be used in combination. That is, when the CRS has two antenna ports, the transmission diversity is automatically set to SFBC, and when the CRS has four antenna ports, the transmission diversity is automatically set to FSTD + SFBC. On the other hand, when the CRS has one antenna port, transmit diversity is not possible and is automatically set to single port transmission.

  The transmission diversity in Table 15 corresponds to the case where only the SFBC (Space Frequency Block Code) is used, or the FSTD (Frequency Selective Transmit diversity) and SFBC are used in combination. In addition to transmit diversity using CRS in the LTE-A system, transmit diversity using DM-RS is also possible. When DM-RS is used, the following transmission diversity is possible.

1. SFBC using DM-RS antenna port 0, 1
2. FSTD + SFBC using DM-RS antenna port 0, 1, 2, 3

  Table 16 summarizes still another method for instructing the DM-RSport and transmission method using the NDI bit for transport block that is not transmitted according to the present invention.

  <SU-MIMO and maximum compose rank 4 for assigning up to 8 layers per UE, and DMRS antenna port in a MU-MIMO (up to 4 co-scheduled UE) transmission scheme for assigning up to 2 layers per UE Transmit diversity notification method 2>

  The transport block NDI bit not transmitted in Table 16 notifies the terminal whether or not the transport block to be transmitted is transmitted in the transmission diversity and what transmission diversity method is used.

  Table 15 corresponds to the case of instructing a method of notifying transmission diversity using CRS, and Table 16 corresponds to the case of instructing a method of notifying transmit diversity using DM-RS. Another method presented by the present invention is to enable both transmit diversity using CRS and transmit diversity using DM-RS. As described above, when both transmission diversity using CRS and transmission diversity using DM-RS are supported, Table 15 shows transmission diversity using CRS and Table 16 shows transmission diversity using DM-RS. As long as they are included in one table.

Table 17 summarizes still another method of instructing the DM-RS port and the transmission method using the NDI bit for transport block that is not transmitted according to the present invention.

  Table 17 can notify the terminal whether or not retransmission is possible, whether or not transmission diversity is applicable, and DM-RS antenna port allocation using the NDI bit for transport block that is not transmitted. When only one transport block is transmitted, the NDI bit for transport block that is not transmitted informs the terminal that the transmission diversity is transmitted or retransmission when the value is set to “0”. Can be used for In transmission diversity of Table 17, when the value of “NDI x” for transport block that is not transmitted is 0 and the index value is 0, transmission diversity is notified to the terminal. The transmission diversity can be applied to both HARQ initial transmission and retransmission. However, in order to facilitate system design, it can be applied to only one of HARQ initial transmission or retransmission. As an example, when transmission diversity is applicable only when retransmission is performed, the “NDI x” is a value that determines whether or not retransmission is possible.

  <SU-MIMO and maximum compose rank 4 for assigning up to 8 layers per UE, and DMRS antenna port in a MU-MIMO (up to 4 co-scheduled UE) transmission scheme for assigning up to 2 layers per UE Transmit diversity notification method 3>

  Tables 15, 16, and 17 can notify the terminal of one transmission scheme among SU-MIMO, MU-MIMO, and transmit diversity using the NDI bit together with the DM-RSport allocation information. Another method presented in the present invention that utilizes the NDI bit for transport block that is not transmitted as described above is to use it to notify the synchronous HARQ.

Table 18 summarizes a method for instructing DM-RS port and Synchronous HARQ transmission using the NDI bit for transport block which is not transmitted according to the present invention.

  <SU-MIMO and maximum compose rank 4 for assigning up to 8 layers per UE, and DMRS antenna port in a MU-MIMO (up to 4 co-scheduled UE) transmission scheme for assigning up to 2 layers per UE Synchronous HARQ notification method>

  The transport block NDI bit not transmitted in Table 18 notifies the terminal whether or not the transport block to be transmitted is transmitted to the Synchronous HARQ. In Synchronous HARQ, retransmission is performed at a constant period, and therefore it is not necessary to transmit an additional PDCCH for retransmission. On the other hand, Synchronous HARQ has a disadvantage that it cannot quickly adapt to changes in the radio channel. As shown in Table 18, when one code word is transmitted, by enabling Synchronous HARQ, the base station and the terminal can use Table 17 when the radio channel environment is appropriate for Synchronous HARQ. By notifying the terminal, the performance can be optimized.

  Table 19 summarizes still another method of instructing DM-RSport and Synchronous HARQ transmission using the NDI bit for transport block that is not transmitted according to the present invention.

  <SU-MIMO and maximum compose rank 4 for assigning a maximum of 8 layers per UE, and DMRS antenna port and synchronous in a MU-MIMO (maximum 4 co-scheduled UE) transmission scheme for assigning a maximum of 2 layers per UE HARQ notification method 2>

  In the case of Table 19, using the NDI bit for transport block that is not transmitted, whether to transmit Synchronous HARQ and whether to apply transmit diversity is transmitted to the terminal. In the case of Table 19, when the NDI bit for transport block that is not transmitted is “0”, Synchronous SU / MU-MIMO or transmit diversity can be notified to the terminal by the index value. In the case of Table 19, Synchronous HARQ with SU / MU-MIMO was designed to be possible only by initial transmission. This is a result of selecting only the most important transmission method in consideration of the limited number of indexes.

  FIG. 12 illustrates a process of notifying transmission diversity using the NDI bit for transport block not transmitted in Tables 15 and 16 designed according to the present invention.

  In FIG. 12, the terminal that has received the PDCCH determines the number of assigned transport blocks in operation 1210. If it is determined in step 1210 that two transport blocks have been transmitted, the terminal uses the DMRS assignment indicator information 1150 of FIG. 11 to assign any DM-RS antenna port to itself in step 1250. Judge whether it was done. If it is determined in step 1210 that one transport block has been transmitted, the UE determines whether transmit diversity is applied according to the value of the NDI bit for transport block that is not transmitted. In step 1220, if the value of the NDI bit for transport block that is not transmitted is “0”, the terminal determines that transmit diversity is applied, and conversely, if the value of the NDI bit for transport block that is not transmitted is “1”, The terminal determines that SU-MIMO or MU-MIMO transmission is performed. The specific transmission information in FIG. 12 is determined by Tables 15 and 16.

  FIG. 13 illustrates a process of notifying whether transmission is initial or initial transmission using NDI bits for transport block that are not transmitted in Table 17 designed according to the present invention, and whether transmission diversity is applicable. It is a thing.

  In FIG. 13, the terminal that has received the PDCCH determines the number of allocated transport blocks in operation 1310. If it is determined in step 1310 that two transport blocks have been transmitted, the UE allocates any DM-RS antenna port to itself using the DMRS assignment indicator information 1150 of FIG. 11 in step 1350. Judge whether it was done. If it is determined in step 1310 that one transport block has been transmitted, the terminal determines whether the transmission is an initial transmission or a retransmission according to the value of the NDI bit for the transport block that is not transmitted. In step 1320, if the value of the NDI bit for transport block that is not transmitted is “0”, the terminal determines that retransmission has been performed, and conversely, if the value of the NDI bit for transport block that is not transmitted is “1”, The terminal determines that the initial transmission has been applied. In addition, when it is determined that one transport block has been transmitted and the value of the NDI bit for transport block that is not transmitted is “0”, the terminal is notified of the applicability of transmission diversity by the DM-RS allocation indicator information 1150. The The specific transmission information in FIG. 13 is determined by Table 17.

  FIG. 14 illustrates a process of notifying the availability of Synchronous HARQ using the NDI bit for transport block not transmitted in Table 18 designed according to the present invention.

  In FIG. 14, the terminal that has received the PDCCH determines the number of allocated transport blocks in operation 1410. If it is determined in step 1410 that two transport blocks have been transmitted, the UE uses the DMRS assignment indicator information 1150 of FIG. 11 to assign any DM-RS antenna port to itself in step 1450. Judge whether it was done. If it is determined in step 1410 that one transport block has been transmitted, the UE determines whether Synchronous HARQ is applied according to the value of the NDI bit for transport block that is not transmitted. In step 1420, if the value of the NDI bit for transport block that is not transmitted is “0”, the terminal determines that Synchronous HARQ is applied, and conversely, if the value of the NDI bit for transport block that is not transmitted is “1”, The terminal determines that Asynchronous HARQ has been applied. The specific transmission information shown in FIG.

  The method for instructing whether or not the Synchronous HARQ transmission is possible corresponds to a case where the base station transmits in the downward direction to the terminal. Such a method for instructing whether or not Synchronous HARQ transmission is possible is also applicable to an upward direction in which a terminal transmits to a base station.

  Although not shown, the above-described embodiment of the present invention can be performed by a terminal and a base station including a wireless communication unit and a controller.

  For example, in the case of a terminal, a wireless communication unit that receives control information including information related to at least one transport block and DMRS (DeModulation Reference Signal) antenna port assignment instruction information from a base station, and the control information And a controller that interprets the DMRS antenna port assignment instruction information according to the number of transmission blocks, and performs the embodiment described in the present invention. Can do.

  Also, in the case of a base station, the number of transmission blocks allocated to the terminal is confirmed, DMRS (DeModulation Reference Signal) antenna port allocation instruction information is selected according to the confirmed number of transmission blocks, and at least one transmission is performed. A controller for generating control information including information related to a block (transport block) and the selected DMRS (DeModulation Reference Signal) antenna port allocation instruction information; and a wireless communication unit for transmitting the generated control information to a terminal. Embodiments described in this invention can be performed.

210: Information for transport block 0 220: Control information for transport block 1 230: DMRS antenna port allocation control information

Claims (24)

In a method for interpreting terminal control information in a wireless communication system,
And information about at least one or more transport blocks (transport block), a receiving step of receiving from the DMRS (DeModulation Reference Signal) base station control information including the antenna port assignment instruction information;
A confirmation step of confirming the number of transmission blocks allocated to the terminal using information on the at least one transmission block ;
Interpreting the number of ranks corresponding to the DMRS antenna port assignment instruction information , the DMRS antenna port and the scrambling sequence according to a predetermined rule based on the confirmed number of transmission blocks. A method for interpreting control information of a terminal characterized by the above. The DMRS antenna port assignment instruction information is:
When the number of transmission blocks is 1,
Rank (Rank) is the maximum 4, wherein if the rank is 1 or 2, wherein the scrambling sequence (scrambling sequence) is 0 or 1, if the rank is 3 or more, the scrambling sequence is 0 The terminal control information interpretation method according to claim 1, wherein the terminal control information interpretation method is provided. The DMRS antenna port assignment instruction information is:
When the number of the transmission blocks is 2,
Rank (Rank) is up to 8, wherein if the rank is 2, the scrambling sequence (scrambling sequence) is 0 or 1, if the rank is 3 or more, said scrambling sequence is 0 The method for interpreting terminal control information according to claim 1, wherein: The interpretation step includes
If the number of transmission blocks is one and initial transmission, the DMRS antenna port assignment instruction information is interpreted only for rank 1,
When the number of transmission blocks is one and retransmission, the DMRS antenna port allocation indication information is interpreted for all ranks,
The terminal control according to claim 1, wherein when the number of transmission blocks is two, the DMRS antenna port allocation indication information is interpreted for all ranks for initial transmission or retransmission. Information interpretation method. The control information is
The apparatus of claim 1, further comprising instruction information indicating whether at least one layer transmitted by the base station is allocated to one terminal or two or more terminals. The terminal control information interpretation method described. The DMRS antenna port assignment instruction information is:
When the number of transmission blocks is 1,
An index indicating DMRS antenna port 0 to which scrambling code 0 is assigned in rank 2 pattern;
An index indicating DMRS antenna port 1 to which scrambling code 0 is assigned in rank 2 pattern;
An index indicating DMRS antenna port 0 to which scrambling code 1 is assigned in rank 2 pattern;
An index indicating DMRS antenna port 1 to which scrambling code 1 is assigned in rank 2 pattern;
An index indicating DMRS antenna ports 0 and 1 to which scrambling code 0 is assigned in the rank 2 pattern, an index indicating DMRS antenna ports 0, 1 and 2 to which scrambling code 0 is assigned in the rank 4 pattern;
Including at least one index indicating DMRS antenna ports 0, 1, 2, and 3 to which scrambling code 0 is assigned in rank 4 pattern,
When the number of the transmission blocks is 2,
An index indicating DMRS antenna ports 0 and 1 to which scrambling code 0 is assigned in rank 2 pattern;
An index indicating DMRS antenna ports 0, 1 and 2 to which scrambling code 0 is assigned in rank 4 pattern;
Index indicating DMRS antenna ports 0 and 1 to which scrambling code 1 is assigned in rank 2 pattern, and index indicating DMRS antenna ports 0, 1, 2, and 3 to which scrambling code 0 is assigned in rank 4 pattern When,
An index indicating DMRS antenna ports 0, 1, 2, 3, 4 to which scrambling code 0 is assigned in rank 8 pattern;
An index indicating DMRS antenna ports 0, 1, 2, 3, 4, 5 to which scrambling code 0 is assigned in rank 8 pattern, and DMRS antenna ports 0, 1 to which scrambling code 0 is assigned in rank 8 pattern An index indicating 2, 3, 4, 5, 6;
Including at least one index indicating DMRS antenna ports 0, 1, 2, 3, 4, 5, 6, 7 to which scrambling code 0 is assigned in rank 8 pattern;
The DMRS antenna port 0 refers to the first antenna port to which DMRS is assigned in the overall reference signal (Reference Signal, RS), and an arbitrary DMRS antenna port n is sequentially set based on the DMRS antenna port 0. The method of claim 1, wherein the control information is interpreted. In a base station control information transmission method in a wireless communication system,
A confirmation stage for confirming the number of transmission blocks allocated to the terminal;
A selecting step of selecting DMRS (DeModulation Reference Signal) antenna port assignment instruction information according to the number of the confirmed transmission blocks;
A generation step of generating control information including information on at least one transport block and the selected DMRS (DeModulation Reference Signal) antenna port assignment instruction information;
A transmission step of transmitting the control information the generated to the terminal; see contains a
The base station control information transmission method , wherein the number of ranks corresponding to the DMRS antenna port allocation instruction information, the DMRS antenna port, and the scrambling sequence are determined in advance based on the number of transmission blocks . The DMRS antenna port assignment instruction information is:
When the number of transmission blocks is 1,
Rank (Rank) is up to 4, wherein if the rank is 1 or 2, wherein the scrambling sequence (scrambling sequence) is 0 or 1, if the rank is 3 or more, the scrambling sequence is zero The base station control information transmission method according to claim 7. The DMRS antenna port assignment instruction information is:
When the number of the transmission blocks is 2,
Rank (Rank) is up to 8, wherein if the rank is 2, the scrambling sequence (scrambling sequence) is 0 or 1, if the rank is 3 or more, said scrambling sequence is 0 The base station control information transmission method according to claim 7, wherein: The selection step includes
When the number of transmission blocks is one and initial transmission, the DMRS antenna port allocation instruction information is selected with rank 1;
When the number of transmission blocks is one and retransmission, the DMRS antenna port assignment instruction information is selected in all ranks,
The base station control information according to claim 7, wherein when the number of transmission blocks is two, the DMRS antenna port assignment instruction information is selected in all ranks for initial transmission or retransmission. Transmission method. The control information is
The apparatus of claim 7, further comprising instruction information indicating whether at least one layer transmitted by the base station is allocated to one terminal or two or more terminals. The base station control information transmission method described. The DMRS antenna port assignment instruction information is:
When the number of transmission blocks is 1,
An index indicating DMRS antenna port 0 to which scrambling code 0 is assigned in rank 2 pattern;
An index indicating DMRS antenna port 1 to which scrambling code 0 is assigned in rank 2 pattern;
An index indicating DMRS antenna port 0 to which scrambling code 1 is assigned in rank 2 pattern;
An index indicating DMRS antenna port 1 to which scrambling code 1 is assigned in rank 2 pattern;
An index indicating DMRS antenna ports 0 and 1 to which scrambling code 0 is assigned in rank 2 pattern;
An index indicating DMRS antenna ports 0, 1 and 2 to which scrambling code 0 is assigned in rank 4 pattern;
Including at least one index indicating DMRS antenna ports 0, 1, 2, and 3 to which scrambling code 0 is assigned in rank 4 pattern,
When the number of the transmission blocks is 2,
An index indicating DMRS antenna ports 0 and 1 to which scrambling code 0 is assigned in rank 2 pattern;
An index indicating DMRS antenna ports 0, 1 and 2 to which scrambling code 0 is assigned in rank 4 pattern;
An index indicating DMRS antenna ports 0 and 1 to which scrambling code 1 is assigned in a rank 2 pattern;
An index indicating DMRS antenna ports 0, 1, 2, 3 to which scrambling code 0 is assigned in rank 4 pattern;
An index indicating DMRS antenna ports 0, 1, 2, 3, 4 to which scrambling code 0 is assigned in rank 8 pattern;
An index indicating DMRS antenna ports 0, 1, 2, 3, 4, 5 to which scrambling code 0 is assigned in rank 8 pattern;
An index indicating DMRS antenna ports 0, 1, 2, 3, 4, 5, 6 to which scrambling code 0 is assigned in rank 8 pattern;
Including at least one index indicating DMRS antenna ports 0, 1, 2, 3, 4, 5, 6, 7 assigned scrambling code 0 in rank 8 pattern;
The DMRS antenna port 0 refers to the first antenna port to which DMRS is assigned in the overall reference signal (Reference Signal, RS), and an arbitrary DMRS antenna port n is sequentially set based on the DMRS antenna port 0 The base station control information transmission method according to claim 7, wherein the control information transmission method increases. In a terminal that receives and interprets control information from a base station in a wireless communication system,
And information about at least one or more transport blocks (transport block), a wireless communication unit for receiving control information including the DMRS (DeModulation Reference Signal) antenna port assignment instruction information from the base station;
The number of transmission blocks allocated to the terminal is confirmed using information on the at least one transmission block, and the DMRS antenna port allocation instruction information corresponds to the number of transmission blocks confirmed. A controller that interprets the number of ranks, the DMRS antenna port, and the scrambling sequence according to a predetermined rule . The DMRS antenna port assignment instruction information is:
When the number of transmission blocks is 1,
Rank (Rank) is up to 4, wherein if the rank is 1 or 2, wherein the scrambling sequence (scrambling sequence) is 0 or 1, if the rank is 3 or more, the scrambling sequence is zero The terminal according to claim 13. The DMRS antenna port assignment instruction information is:
When the number of the transmission blocks is 2,
Rank (Rank) is up to 8, wherein if the rank is 2, the scrambling sequence (scrambling sequence) is 0 or 1, if the rank is 3 or more, said scrambling sequence is 0 The terminal according to claim 13, characterized in that: The controller is
When the number of transmission blocks is one and initial transmission, the DMRS antenna port assignment instruction information is interpreted for rank 1,
When the number of transmission blocks is one and retransmission, the DMRS antenna port allocation indication information is interpreted for all ranks,
The terminal of claim 13, wherein when the number of transmission blocks is two, the DMRS antenna port assignment instruction information is interpreted for all ranks for initial transmission or retransmission. The control information is
The apparatus of claim 13, further comprising instruction information indicating whether at least one layer transmitted by the base station is allocated to one terminal or two or more terminals. The listed terminal. The DMRS antenna port assignment instruction information is:
When the number of transmission blocks is 1,
An index indicating DMRS antenna port 0 to which scrambling code 0 is assigned in rank 2 pattern;
An index indicating DMRS antenna port 1 to which scrambling code 0 is assigned in rank 2 pattern;
An index indicating DMRS antenna port 0 to which scrambling code 1 is assigned in rank 2 pattern;
An index indicating DMRS antenna port 1 to which scrambling code 1 is assigned in rank 2 pattern;
An index indicating DMRS antenna ports 0 and 1 to which scrambling code 0 is assigned in rank 2 pattern;
An index indicating DMRS antenna ports 0, 1 and 2 to which scrambling code 0 is assigned in rank 4 pattern;
Including at least one index indicating DMRS antenna ports 0, 1, 2, and 3 to which scrambling code 0 is assigned in rank 4 pattern,
When the number of the transmission blocks is 2,
An index indicating DMRS antenna ports 0 and 1 to which scrambling code 0 is assigned in rank 2 pattern;
An index indicating DMRS antenna ports 0, 1 and 2 to which scrambling code 0 is assigned in rank 4 pattern;
An index indicating DMRS antenna ports 0 and 1 to which scrambling code 1 is assigned in a rank 2 pattern;
An index indicating DMRS antenna ports 0, 1, 2, 3 to which scrambling code 0 is assigned in rank 4 pattern;
An index indicating DMRS antenna ports 0, 1, 2, 3, 4 to which scrambling code 0 is assigned in rank 8 pattern;
An index indicating DMRS antenna ports 0, 1, 2, 3, 4, 5 to which scrambling code 0 is assigned in rank 8 pattern;
An index indicating DMRS antenna ports 0, 1, 2, 3, 4, 5, 6 to which scrambling code 0 is assigned in rank 8 pattern;
Including at least one index indicating DMRS antenna ports 0, 1, 2, 3, 4, 5, 6, 7 assigned scrambling code 0 in rank 8 pattern;
The DMRS antenna port 0 refers to the first antenna port to which DMRS is assigned in the overall reference signal (Reference Signal, RS), and an arbitrary DMRS antenna port n is sequentially set based on the DMRS antenna port 0. The terminal according to claim 13, wherein the terminal increases. In a base station that transmits control information in a wireless communication system,
Confirm the number of transmission blocks allocated to the terminal, select DMRS (DeModulation Reference Signal) antenna port allocation instruction information according to the number of the confirmed transmission blocks, and information on at least one transmission block (transport block) When a controller for generating control information including the selected DMRS (DeModulation Reference Signal) antenna port assignment instruction information;
A wireless communication unit for transmitting control information said generated in the terminal; only contains,
The base station , wherein the number of ranks corresponding to the DMRS antenna port assignment instruction information, the DMRS antenna port, and the scrambling sequence are determined in advance based on the number of transmission blocks . The DMRS antenna port assignment instruction information is:
When the number of transmission blocks is 1,
Rank (Rank) is the maximum 4, wherein if the rank is 1 or 2, wherein the scrambling sequence (scrambling sequence) is 0 or 1, if the rank is 3 or more, the scrambling sequence is 0 The base station according to claim 19, wherein there is a base station. The DMRS antenna port assignment instruction information is:
When the number of the transmission blocks is 2,
Rank (Rank) is the maximum 8, wherein if the rank is 2, the scrambling sequence (scrambling sequence) is 0 or 1, if the rank is 3 or more, the scrambling sequence is 0 The base station according to claim 19. The controller is
When the number of transmission blocks is one and initial transmission, the DMRS antenna port allocation instruction information is selected with rank 1;
When the number of transmission blocks is one and retransmission, the DMRS antenna port assignment instruction information is selected in all ranks,
The base station according to claim 19, wherein when the number of transmission blocks is two, the DMRS antenna port assignment instruction information is selected for all ranks for initial transmission or retransmission. The control information is
The apparatus of claim 19, further comprising instruction information indicating whether at least one layer transmitted by the base station is allocated to one terminal or two or more terminals. The listed base station. The DMRS antenna port assignment instruction information is:
When the number of transmission blocks is 1,
An index indicating DMRS antenna port 0 to which scrambling code 0 is assigned in rank 2 pattern;
An index indicating DMRS antenna port 1 to which scrambling code 0 is assigned in rank 2 pattern;
An index indicating DMRS antenna port 0 to which scrambling code 1 is assigned in rank 2 pattern;
An index indicating DMRS antenna port 1 to which scrambling code 1 is assigned in rank 2 pattern;
An index indicating DMRS antenna ports 0 and 1 to which scrambling code 0 is assigned in rank 2 pattern;
An index indicating DMRS antenna ports 0, 1 and 2 to which scrambling code 0 is assigned in rank 4 pattern;
Including at least one index indicating DMRS antenna ports 0, 1, 2, 3 to which scrambling code 0 is assigned in rank 4 pattern;
When the number of the transmission blocks is 2,
An index indicating DMRS antenna ports 0 and 1 to which scrambling code 0 is assigned in rank 2 pattern;
An index indicating DMRS antenna ports 0, 1 and 2 to which scrambling code 0 is assigned in rank 4 pattern;
An index indicating DMRS antenna ports 0 and 1 to which scrambling code 1 is assigned in a rank 2 pattern;
An index indicating DMRS antenna ports 0, 1, 2, 3 to which scrambling code 0 is assigned in rank 4 pattern;
An index indicating DMRS antenna ports 0, 1, 2, 3, 4 to which scrambling code 0 is assigned in rank 8 pattern;
An index indicating DMRS antenna ports 0, 1, 2, 3, 4, 5 to which scrambling code 0 is assigned in rank 8 pattern;
An index indicating DMRS antenna ports 0, 1, 2, 3, 4, 5, 6 to which scrambling code 0 is assigned in rank 8 pattern;
Including at least one index indicating DMRS antenna ports 0, 1, 2, 3, 4, 5, 6, 7 assigned scrambling code 0 in rank 8 pattern;
The DMRS antenna port 0 refers to the first antenna port to which DMRS is assigned in the overall reference signal (Reference Signal, RS), and an arbitrary DMRS antenna port n is sequentially set based on the DMRS antenna port 0. The base station according to claim 19, wherein the base station increases.

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