KR101688551B1 - Method for indicating user specific dmrs antenna port in wireless communication systems - Google Patents

Abstract

The reference signal is used to measure the state of a channel between a base station and users, such as channel strength, distortion, interference strength, and Gaussian noise, in a wireless mobile communication system, It is a signal used to assist in demodulation and decoding. Another use of the reference signal is to measure the radio channel condition. The receiver can determine the state of the wireless channel between itself and the transmitter by measuring the received strength of the reference signal transmitted by the transmitter at the promised transmit power over the wireless channel. The state of the radio channel thus determined is used to determine what data rate the receiver will request from the transmitter.
Recent 3G wireless mobile communication system standards such as 3GPP LTE (-A) or IEEE 802.16m use multiple subcarriers such as OFDM (A) (orthogonal frequency division multiplexing (multiple access) It mainly adopts the multiple access technique. In the case of a wireless mobile communication system using the multiple access scheme using multiple subcarriers, channel estimation and measurement (hereinafter referred to as " measurement ") are performed according to how many time symbols and subcarriers ) Performance. In addition, channel estimation and measurement performance is also affected by how much power is allocated to the reference signal. Therefore, when more radio resources such as time, frequency, and power are allocated to the reference signal, the channel estimation and measurement performance improves, thereby improving the demodulation and decoding performance of the received data symbol and increasing the accuracy of channel state measurement.
However, in a general mobile communication system, since radio resources such as time, frequency, and transmission power for transmitting a signal are limited, when radio resources are allocated to a reference signal, a radio resource Is relatively decreased. For this reason, the radio resources allocated to the reference signal should be appropriately determined in consideration of the system throughput.
The present invention relates to a method for allocating demodulation reference signal resources that are uniquely allocated to UEs in LTE-A.

Description

TECHNICAL FIELD [0001] The present invention relates to a method of indicating a DMRS antenna port specific to a user in a wireless communication system,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to a wireless mobile communication system, and more particularly to a wireless mobile communication system employing a multiple access scheme using multi-carriers such as OFDMA (Orthogonal Frequency Division Multiple Access) (CSI-RS, reference signal for channel state measurement) transmitted by a base station in order to facilitate measurement of a channel state (radio channel state).

The present mobile communication system is moving away from providing initial voice-oriented services and is developing a high-speed and high-quality wireless packet data communication system for providing data service and multimedia service. To this end, 3GPP, 3GPP2, IEEE, and other standardization organizations are working on a third generation evolved mobile communication system standard applying multi-carrier multiple access scheme. Recently, various mobile communication standards such as Long Term Evolution (LTE) of 3GPP, Ultra Mobile Broadband (UMB) of 3GPP2, and IEEE 802.16m have been proposed as a high speed and high quality wireless packet data transmission service Was developed to support.

The existing third generation mobile communication system such as LTE, UMB and 802.16m is based on multi-carrier multiple access scheme. In order to improve transmission efficiency, existing multiple-input multiple output (MIMO) (AMC), and channel sensitive (scheduling) channel scheduling methods, which are used in a wide variety of applications. Various techniques described above improve the transmission efficiency by adjusting the amount of data to be transmitted or transmitted from various antennas according to channel quality and selectively transmitting data to a user having good channel quality, Improves system capacity performance. Most of these schemes operate based on channel state information between an evolved Node B (eNB) and a base station (UE) and a user equipment (MS) It is necessary to measure the channel state between the CSI-RS and the channel status indication reference signal (CSI-RS). The above-mentioned eNB refers to a downlink transmission and uplink receiving apparatus located in a certain place, and an eNB performs transmission and reception for a plurality of cells. In one mobile communication system, a plurality of eNBs are geographically dispersed, and each eNB performs transmission and reception for a plurality of cells.

In a mobile communication system, time, frequency, and power resources are limited. Therefore, allocating more resources to the reference signal can reduce the amount of resources that can be allocated to the traffic channel (transmission of data traffic), which can reduce the absolute amount of data to be transmitted. In this case, although the performance of channel measurement and estimation may be improved, the absolute amount of data to be transmitted is reduced, so that the overall system capacity performance may be lowered. Therefore, a proper allocation between the resources for the reference signal and the resources for the traffic channel transmission is required to achieve optimal performance in terms of overall system capacity.

In the third generation evolved radio mobile communication system standard, the reference signal is divided into a common reference signal (CRS) and a dedicated reference signal (DRS) according to the dedicated signal for a specific terminal as follows.

1) Common Reference Signal: In 3GPP LTE system, it is referred to as Cell-specific RS or CRS (Common RS), and is a reference signal transmitted to all UEs in a cell to which the BS belongs. A reference signal pattern that can be distinguished by antenna port (antenna port) is defined so that channel estimation and measurement can be performed when transmission using multiple antennas is performed. LTE systems support up to four antenna ports.

2) Dedicated Reference Signal: This is a reference signal transmitted separately from the common reference signal, and is transmitted only to a specific terminal specified by the base station. In the 3GPP LTE (-A) system, it is also referred to as a UE-specific RS or DRS. In general, a base station is used to support data traffic channel transmission using non-codebook based precoding.

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) which enables channel estimation for up to 8 layers in addition to the above CRS and DRS is also transmitted. Like the DRS, the DMRS is transmitted separately from the CRS, and is transmitted only to the specific UE designated by the BS. In LTE-A, the downlink signal is transmitted using the OFDMA transmission scheme that utilizes the frequency domain and the time domain simultaneously. In the LTE-A, the downlink is transmitted in a frequency domain consisting 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 a base station performs downlink transmission consists of one or more RBs in the frequency domain and one subframe in the time domain. Also, a radio resource transmitted to one subcarrier in one OFDM symbol interval is called a RE (resource element).

The LTE-A system can perform transmission using a plurality of layers when performing transmission using SU-MIMO or MU-MIMO. In this case, when a plurality of layers are transmitted, a DMRS resource should be allocated 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. In the following, the terminology of the DMRS resource and the term of the DMRS port are used in combination.

1 shows a location where a DMRS is transmitted in a radio resource in an LTE-A composed of one RB and one subframe. In FIG. 1, 100 indicates that an eNB can perform DMRS transmission for two layers Is a Rank 2 DMRS pattern. When two DMRSs are transmitted using the Rank 2 DMRS pattern shown in FIG. 1, the DMRSs for the respective layers are orthogonally spread with spreading length 2 at positions 101 and 102, and then transmitted to the CDM. In this way, the DMRS is orthogonally spread and transmitted at the positions 103 and 104 as well. Also in FIG. 1, the same DMRS is transmitted in consecutive RE indicated in the same shape (blue). As a result, the DMRS signals for the two DMRS antenna ports are transmitted in the same frequency and time domain as the CDM method.

In FIG. 1, reference numeral 110 denotes a Rank 4 DMRS pattern that enables an eNB to perform DMRS transmission for four layers. The Rank 4 DMRS pattern of FIG. 1 transmits a DMRS signal in a manner of orthogonal spreading with a spreading length 2 equal to 100. The difference between 110 and 100 is that additional REs are used to perform transmissions on the four DMRS antenna ports. It can be seen in FIG. 1 that using two times RE to transmit DMRS compared to 110 is 100.

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

In the LTE-A system, the rank of the signal transmitted by the eNB is variable according to the state of the downlink channel. Since the rank of the eNB transmission signal is variable, the DMRS pattern to be used is variable. That is, if it is possible to transmit a layer having a large number of channels according to the situation, the eNB may use the rank 8 DMRS pattern as shown in FIG. 1, and if it can transmit only a layer with a small number of channels, The same rank 2 DMRS pattern can be used.

Since the DMRS pattern transmitted by the eNB may change in time and the DMRS port allocated to one UE in the corresponding DMRS pattern may also be variable, the eNB may transmit a downlink traffic channel Which DMRS pattern of which DMRS pattern to use to demodulate.

As shown in FIG. 1, when there are three DMRS patterns and a maximum of 8 DMRS antenna ports are available, one way for the eNB to inform the UE about the DMRS is to transmit 2-bit information indicating the DMRS pattern and 8 DMRS antenna ports And transmits 8 bits to the UE for indicating which one to use in a bit map format. That is, a total of 10 bits are used to notify which DMRS resource is allocated to one UE. For example, suppose the Rank 2 DMRS pattern is '00', the Rank 4 DMRS pattern is '01', and the Rank 8 DMRS pattern is indicated as '10', the eNB sends '01' and '01100000' , The corresponding UE can be notified that the DMRS antenna port 1, 2 has been allocated in the Rank 4 DMRS pattern.

Notifying the DMRS resource in the above manner has a problem that the eNB needs to transmit a total of 10 bits of information to the UE. The number of bits is relatively large compared to the information actually transmitted and may be a factor for reducing the downlink system capacity.

Another problem of the above method is that the UE receiving the information on the DMRS resource can not know which DMRS antenna port is assigned to the UEs other than the UE since the UE knows only the information on the DMRS antenna port allocated to the UE. In the case of a wireless communication system in which downlink transmission is performed to an MU-MIMO like the LTE-A system, it can be seen that while one UE receives its signal, transmission is also performed to another UE in the same frequency interval and time interval This fact can be used to implement a more effective receiver algorithm. For example, in the case of a minimum mean square error (MMSE) receiver widely used in modern mobile communication systems, it is necessary to know the exact size of the interference to obtain optimized performance. In order to accurately measure the magnitude of the interference in the MMSE receiver, it is first necessary to accurately determine whether interference exists. However, the DMRS resource notification method mentioned above can not notify the UE of this information.

In order to overcome the limitations and problems of the conventional technique of notifying the DMRS resource, the DMRS resource is effectively notified to the UE while simultaneously transmitting to the MU-MIMO. A method is needed.

In an LTE-A system, one eNB can assign up to eight DMRS antenna ports to one UE. Each antenna port allows the eNB to perform channel estimation for one of the multiple layers transmitted by MIMO. The eNB informs which DMRS antenna port to allocate to the UE using a Physical Downlink Control Channel (PDCCH) designed to deliver control information to the UE. The allocation of the DMRS antenna port is closely related to the MIMO transmission method of the eNB since the eNB requires one for each layer when performing the MIMO transmission. 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.

The present invention effectively notifies UEs of DMRS resource allocation information necessary for receiving a downlink traffic signal in an LTE-A system, and at the same time, notifies a corresponding UE of which DMRS resource transmission is performed for another UE in the same frequency interval and time interval And to provide a method for effectively notifying the user.

A method for allocating a demodulation reference signal (DMRS) resource to a base station in a wireless communication system for achieving the object of the present invention is a method for allocating one or more transport block information A control information generation step of generating control information including DMRS resource indicator information, a definition step of defining a DMRS resource allocation method by the DMRS resource indicator according to whether or not the transport block is used, And transmitting the data to the terminal through a channel.

Also, in the wireless communication system of the present invention, the control information receiving method of the UE receiving the control signal including the allocation information for the demodulation reference signal (DMRS) resource includes receiving control information Determining information on at least one of transport block information and DMRS resource indicator information from the received control information, determining whether to use DMRS resource allocation information by the DMRS resource indicator according to whether the transport block is used, And a received signal processing step of processing the received signal according to the analysis result.

According to the present invention, the LTE-A system efficiently notifies the UE of the DMRS resource allocation information necessary for receiving the downlink traffic signal, and at the same time, notifies the corresponding UE of the transmission of the other UEs in the same frequency interval and time interval, It can be notified effectively.

1 is a diagram illustrating a location where a DMRS is transmitted in a radio resource in an LTE-A composed of one RB and one subframe.
FIG. 2 illustrates DMRS antenna port assignment information transmitted in a PDCCH according to the present invention in LTE-A; FIG.
FIG. 3 illustrates a method in which an eNB allocates a DMRS antenna port to a UE according to the present invention, and an eNB notifies which DMRS antenna port is used for transmission to other UEs capable of generating interference in the same frequency and time interval Fig.
FIG. 4 is a diagram illustrating an example of a case where a UE receives a DMRS antenna port assignment index transmitted by an eNB according to an embodiment of the present invention to determine which DMRS antenna port is allocated to itself, and at the same time, ≪ / RTI > FIG. 5 illustrates a method by which a UE determines which DMRS antenna port is used for transmission to another UE.
FIG. 5 illustrates the use of two scrambling sequences in the same time and frequency resource to identify a DMRS antenna port when the number of layers transmitted in an MU-MIMO transmission is 3 or 4; FIG.
FIG. 6 is a block diagram illustrating an embodiment of the present invention. Referring to FIG. 6, a 1-bit control information SU / MU-MIMO indicator for distinguishing whether transmission of an eNB is SU-MIMO or MU- Fig.
7 is a diagram illustrating a case where an eNB allocates a DMRS antenna port to a UE when using the SU / MU-MIMO indicator according to an embodiment of the present invention, and a transmission to another UE capable of generating interference in the same frequency and time interval is performed using a DMRS antenna port Fig. 1 is a diagram showing a method by which an eNB notifies whether eNB is used.
FIG. 8 is a diagram illustrating a case where the UE receives the DMRS antenna port allocation index transmitted by the eNB when the SU / MU-MIMO indicator is used according to the present invention, determines which DMRS antenna port is allocated to itself, Lt; RTI ID = 0.0 > UE < / RTI > to another UE that may cause interference to the received signal of the UE.
9 is a diagram illustrating a method for allocating a DM-RS antenna port to an eNB using Table 8;
10 is a diagram illustrating a method in which a terminal interprets a DM-RS antenna port when an eNB allocates a DM-RS antenna port using Table 8;
11 is a diagram illustrating DMRS antenna port assignment information transmitted from an LTE-A to a PDCCH according to yet another embodiment of the present invention.
12 is a diagram illustrating a process of notifying transmit diversity using NDI bits for transport blocks that are not transmitted in Tables 15 and 16 designed according to the present invention.
FIG. 13 is a diagram illustrating a process of notifying whether retransmission, initial transmission, and transmit diversity are applied using NDI bits for transport blocks that are not transmitted in Table 17 designed according to the present invention.
14 is a diagram illustrating a process of notifying whether or not a Synchronous HARQ is applied using an NDI bit for a transport block that is not transmitted in Table 18 designed according to the present invention.

In the LTE-A system, MIMO is divided into SU-MIMO where all layers transmitted by an eNB are allocated to one UE and MU-MIMO allocated to two or more UEs. In case of SU-MIMO, the number of layers that can be allocated to one UE is 1, 2, 3, 4, 5, 6, 7, That is, in the case of SU-MIMO, one to eight DMRS antenna ports can be allocated to the UE according to the determination of the eNB. On the other hand, in the case of MU-MIMO, the following restrictions are imposed on the complexity of implementation.

1. MU-MIMO performs transmission to up to four UEs using the same frequency resource and time resource.

2. MU-MIMO can assign up to 2 layers to one UE.

3. MU-MIMO performs transmission for up to 4 layers using the same frequency resource and time resource. That is, one UE can allocate one layer to each UE, or two UEs can allocate two UEs to two UEs. However, two UEs can not be allocated to two UEs.

Also, the SU-MIMO and the MU-MIMO may be changed in every subframe (1 msec) according to the judgment of the eNB. In the LTE-A system, MU-MIMO may limit the transmission of eNBs to a maximum of 4 layers by replacing the composite rank of MU-MIMO by 4.

One of the MIMO-related constraints that the LTE-A system and the LTE system have in common is that only one transport block can be transmitted in one layer. Here, the transport block is transmitted as a unit of traffic information from the upper layer of the LTE and LTE-A systems to the physical layer, and is encoded, modulated and transmitted. In the LTE and LTE-A systems, the eNB can transmit up to two transport blocks to one UE using the same frequency and time resources. In this case, when one transport block is transmitted, it is transmitted as one layer to the UE, but when two transport blocks are transmitted, at least two layers are used for transmission.

The present invention is based on the fact that the constraints of the layer allocation of MU-MIMO and SU-MIMO and one transport block are transmitted in one layer while two transport blocks are transmitted in two or more layers, In this paper, we propose a method to minimize the amount of control information required to notify the DMRS antenna port allocated to the DMRS. In addition, the eNB provides a method of notifying the UE whether the signal received by the UE is part of the MU-MIMO signal or SU-MIMO received alone from the eNB. If the signal received by the corresponding UE is a part of the MU-MIMO signal, it is informed to which DMRS antenna port the signal for the other UEs is transmitted, and utilized for measurement and removal of the interference component of the corresponding UE.

In the present invention, a method of notifying a terminal of a DMRS antenna port is performed by using information on a DMRS antenna port and information on a transport block already existing in the LTE and LTE-A system. As mentioned earlier, two transport blocks can always be transmitted using more than one layer. Also, one transport block is always transmitted in only one layer. When the eNB transmits PDSCH, which is a traffic channel in LTE and LTE-A, the eNB sends control information to the corresponding UE to inform the UE whether transmission for one transport block or transmission for two transport blocks is performed on the PDCCH send. The present invention notifies the DMRS antenna port allocated to each UE with a minimum amount of control information by linking the information on the transport block and the information for allocating the DMRS antenna port.

FIG. 2 illustrates DMRS antenna port assignment information transmitted in the PDCCH according to the present invention in LTE-A.

In FIG. 2, the DMRS antenna port allocation information (or DMRS resource indicator, hereinafter the same) is described as " control information on DMRS antenna port indication ", and is transmitted to the UE as part of control information transmitted on the PDCCH. As shown in FIG. 2, the UE receiving the control information on the PDCCH refers to the control information on the transport block 0 and the control information on the DMRS antenna port 230 referring to the control information on the transport block 1 Decide how to judge. The information included in the 210 corresponding to the control information of the transport block 0 is information on whether the corresponding transport block is transmitted and, if valid, the size of the corresponding transport block. Also, the information included in 220 corresponding to the control information of the transport block 1 is information on whether the corresponding transport block is transmitted and, if valid, the size of the corresponding transport block. The eNB uses 210 and 220 to inform the UE whether the transport block 0 or transport block 1 is transmitted or both are transmitted to the UE. The control information for the transport blocks 210 and 220 of FIG. 2 exists in the LTE system and exists in the LTE-A system, which is an enhanced version of the LTE system. In the present invention, the control information on the transport block and the information on the DMRS resource indicator of 230 are associated with each other, such as 210 and 220 in FIG. 2, and the DMRS antenna port is allocated using the minimum number of bits.

Table 1 summarizes the indexes used to notify the DMRS antenna port information allocated to the UE according to the present invention and what each index means. Table 1 shows the DMRS antenna port assignment for MIMO transmission as follows.

<System characteristics 1>

1. SU-MIMO transmission for 1 to 8 layers

2. MU-MIMO transmission that allocates a maximum of 2 layers to one UE

3. MU-MIMO transmission to up to 4 UEs

4. MU-MIMO transmission for up to 4 layers (MU-MIMO composite rank maximum value 4)

Table 1 shows not only the function of notifying the DMRS antenna port allocated to the UE that is scheduled for the eNB transmission as described above but also the possibility of generating interference in the same time and frequency interval to the UE allocating the DMRS antenna port in case of MU- And notifies which DMRS antenna port the signal for the other UE is made.

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

Accordingly, when the transport block 0 is transmitted, the transport block 1 is transmitted, and the transport block 0 and the transport block 1 are both transmitted, the UE of the present invention transmits the transport block 0 Interpret the indexes differently. For example, the meaning of the eNB corresponding to the index value 3 to the UE is interpreted differently depending on how 210 and 220 of FIG. 2 are set. 2, it is assumed that the transport block 0 is not transmitted but only the transport block 1 is transmitted by 220 in FIG. In this case, the UE is assigned the DMRS antenna port 3 in the rank 4 DMRS pattern corresponding to 110 in FIG. 1, and the MU-MIMO transmission allocated to the other UEs in the DMRS antenna port 0, 1 and 2 is performed from the eNB . That is, the UE is informed of the DMRS antenna port allocated to itself, and at the same time, it is possible to determine which DMRS antenna port is used for transmission for another UE, which generates an interference effect on itself, .

When allocating the DMRS antenna port using Table 1, a total of 4 bits of information is required. This is because the index of each column in Table 1 is 10 at the maximum. That is, when Table 1 is used, 4 bits of DMRS antenna port allocation and interference related information are transmitted to 230 of FIG.

MU-MIMO (maximum of 4 co-scheduled UEs) that allocates a maximum of 2 layers per UE and SU-MIMO that allocates up to 8 layers per UE and DMRS antenna port and interference notification method Transport Block 0 Enabled
Transport Block 1 Disabled Transport Block 0 Disabled
Transport Block 1 Enabled Transport Block 0 Enabled
Transport Block 1 Enabled Index Message Index Message Index Message 0 Rank 2 pattern,
DMRS port 0 allocated, DMRS port 1 not used 0 Rank 2 pattern,
DMRS port 1 allocated, DMRS port 0 used by other UE 0 Rank 2 pattern,
DMRS port 0, 1 allocated One Rank 2 pattern,
DMRS port 0 allocated, DMRS port 1 used by other UE One Rank 4 pattern,
DMRS port 2 allocated,
DMRS port 0, 1 used by other UEs,
DMRS port 3 not used One Rank 4 pattern,
DMRS port 0, 1 allocated,
DMRS port 2 used by other UEs,
DMRS port 3 not used 2 Rank 4 pattern,
DMRS port 0 allocated,
DMRS port 1, 2 used by other UEs,
DMRS port 3 not used 2 Rank 4 pattern,
DMRS port 2 allocated,
DMRS ports 0, 1, 3 used by other UEs 2 Rank 4 pattern,
DMRS port 0, 1, 2 allocated,
DMRS port 3 not used 3 Rank 4 pattern,
DMRS port 1 allocated,
DMRS port 0, 2 used by other UEs,
DMRS port 4 not used 3 Rank 4 pattern,
DMRS port 3 allocated,
DMRS port 0, 1, 2 used by other UEs 3 Rank 4 pattern,
DMRS port 0, 1 allocated,
DMRS port 2, 3 used by other UEs 4 Rank 4 pattern,
DMRS port 0 allocated,
DMRS port 1, 2, 3 used by other UEs 4 reserved 4 Rank 4 pattern,
DMRS port 2, 3 allocated,
DMRS port 0, 1 used by other UEs 5 Rank 4 pattern,
DMRS port 1 allocated,
DMRS ports 0, 2, 3 used by other UEs 5 reserved 5 Rank 4 pattern,
DMRS port 0, 1, 2, 3 allocated 6 reserved 6 reserved 6 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4 allocated,
DMRS ports 5, 6, 7 not used 7 reserved 7 reserved 7 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5 allocated
DMRS port 6, 7 not used 8 reserved 8 reserved 8 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5, allocated
DMRS port 7 not used 9 reserved 9 reserved 9 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5, 6, 7 allocated

FIG. 3 illustrates a method in which an eNB allocates a DMRS antenna port to a UE according to the present invention, and an eNB notifies which DMRS antenna port is used for transmission to other UEs capable of generating interference in the same frequency and time interval FIG.

In step 310 of FIG. 3, the eNB performs scheduling for specific time and frequency resources. Here, scheduling refers to a process of determining which UE or UEs are to be allocated specific time and frequency resources, and determining a data transmission rate to be transmitted to each UE. In step 310 of FIG. 3, scheduling is performed, and the eNB sets the number of UEs to be cascaded together to N. FIG. In this case, SU-MIMO transmission is performed when N is 1, and MU-MIMO transmission is performed when 2, 3, or 4 is performed. After scheduling is completed in step 310 of FIG. 3, the eNB performs an index for the DMRS antenna port notification for the j &lt; th &gt; UE from step 320. In FIG. 3, a variable j is a variable for identifying UEs to be cascaded, and this value is initialized to 0 in step 320. In step 330, the eNB determines the number of transport blocks allocated to the j th casched UE. The number of transport blocks that can be transmitted to one UE is 1 or 2. When one transport block is transmitted to the UE, the corresponding 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 the transport block 0 is transmitted, the eNB selects an index for notifying the DMRS antenna port to be allocated to the j-th UE in the first column of Table 1 in step 340. In the first column of Table 1, if only the transport block 0 is transmitted to the UE and the transport block 1 is not transmitted, a DMRS antenna port is allocated. If there is another UE in the same time and frequency interval, Is used.

Also, if it is determined in step 330 of FIG. 3 that only the transport block 1 is transmitted, the eNB selects an index for notifying the DMRS antenna port to be allocated to the j-th UE in the second column of Table 1 in step 350. In the second column of Table 1, if only the transport block 1 is transmitted to the UE and the transport block 0 is not transmitted, the DMRS antenna port is allocated. If there is another UE in the same time and frequency interval, Is used.

If it is determined in step 330 of FIG. 3 that both the transport block 0 and the transport block 1 are transmitted, the eNB selects an index for notifying the DMRS antenna port to be allocated to the j-th UE in the third column of Table 1 in step 360 . In the third column of Table 1, the DMRS antenna port is allocated when both the transport block 0 and the transport block 1 are transmitted to the UE, and if there are other UEs in the same time and frequency interval and if there are DMRS antenna ports It is used to notify.

After determining the DMRS antenna port allocation index for the jth UE to be cascaded in steps 340, 350, or 360 of FIG. 3, it is determined in step 370 whether the DMRS antenna port allocation index for all coscheduled UEs is determined. In step 370, if the value of j is N, the DMRS antenna port allocation index for all coscheduled UEs is determined. When the DMRS antenna port allocation index for all coscheduled UEs is determined in step 370, the corresponding DMRS antenna port allocation index is notified to each UE using the PDCCH as in step 390 of FIG. Also, if there is a UE whose cosearchuled UE's DMRS antenna port allocation index is not determined, the DMRS antenna port allocation index is determined for the corresponding coscheduled UE in step 330.

FIG. 4 is a diagram illustrating an example of a case where a UE receives a DMRS antenna port assignment index transmitted by an eNB according to an embodiment of the present invention to determine which DMRS antenna port is allocated to itself, and at the same time, The UE determines which DMRS antenna port is used for transmission to another UE.

In step 405 of FIG. 4, the UE performs PDCCH blind decoding. Since the blind decoding in the process 405 does not know at what time and frequency interval the PDCCH transmission for the UE itself is performed, decoding is performed on the assumption that transmission is performed in a plurality of candidate time and frequency intervals, Only the corresponding decoded control information is used in the LTE and LTE-A systems.

In step 405 of FIG. 4, the UE performs blind decoding and determines in step 410 whether a downlink scheduling PDCCH for itself is received. If it is determined in step 410 that the downlink scheduling PDCCH for the UE is not received, the UE returns to step 405 and performs PDCCH blind decoding again. If the UE determines in step 410 that a PDCCH for downlink scheduling for itself is received, the UE confirms the downlink control information (DCI) on the PDCCH as in step 415. [ The downlink control information includes transport block 0, control information for transport block 1, DMRS antenna port allocation control information, and other control information as shown in FIG.

4, the UE confirms that the transport block 0 related control information 210 and the transport block 1 related control information 220 have transmitted only the transport block 0, only the transport block 1, or the transport block 0 And transport block 1 are both transmitted. If it is determined in step 420 that only the transport block 0 has been transmitted, the UE determines in step 425 whether the DMRS antenna port allocation information 230 allocated to the DMRS antenna port through the message in the first column of Table 1 corresponding to the index indicated by the DMRS antenna port allocation control information 230 in FIG. . In step 425, the UE checks whether the MU-MIMO is transmitted to other UEs together with which DMRS antenna port the UEs are using. If it is determined in step 420 that only the transport block 1 is transmitted, the UE determines in step 430 whether or not the DMRS antenna port allocation information 230 allocated through the second column of Table 1 corresponding to the index indicated by the DMRS antenna port allocation control information 230 in FIG. . In step 430, the UE checks whether the MU-MIMO is transmitted to other UEs together with which DMRS antenna port the UEs are using. If it is determined in step 420 that both the transport block 0 and the transport block 1 have been transmitted, in step 435, the UE determines whether the DMRS antenna allocated through the third column of Table 1 corresponding to the index indicated by the DMRS antenna port allocation control information 230 in FIG. Check the information about the port. In step 425, the UE checks whether the MU-MIMO is transmitted to other UEs together with which DMRS antenna port the UEs are using.

In the case of a UE that has confirmed the DMRS antenna port allocated to itself in steps 425 and 430 of FIG. 4, only the transmission for either the transport block 0 or the transport block 1 is received from the eNB. In this case, the UE estimates a channel for one layer using one allocated DMRS antenna port as in step 440. In step 435, a UE that has identified the DMRS antenna port allocated to it receives transmissions from both the transport block 0 and the transport block 1 from the eNB. In this case, the UE performs channel estimation for a plurality of layers corresponding to the allocated DMRS antenna ports, as in step 445. In step 450, the UE performs channel estimation in step 440 and in step 445. In step 450, the UE determines whether other UEs are transmitted in the time and frequency space. That is, in step 450, the UE determines whether the received signal is an SU-MIMO transmission that performs transmission for one UE in the same time and frequency interval or an MU-MIMO transmission that performs transmission for a plurality of UEs do. The presence or absence of MU-MIMO in step 450 can be determined using the existence of transmission to another UE and the DMRS antenna port information allocated to another UE, which are notified together with the DMRS antenna port allocation information of steps 425, 430 and 435. If it is determined in step 450 that the MU-MIMO transmission is determined, in step 455, the UE detects a signal on a DMRS antenna port allocated to a UE other than itself and utilizes the detected signal to improve the performance of its received signal. One way to improve the performance of the received signal in step 455 is to measure the signal strength of the DMRS allocated to the other UE and utilize it in a Minimum Mean Square Estimator (MMSE) receiver. Another method is to determine which DMRS antenna port is allocated to another UE, and then utilize the interference cancellation receiver by using it. If it is determined in step 450 that SU-MIMO transmission other than MU-MIMO is to be performed, the UE performs the SU-MIMO reception method under the assumption that the eNB does not perform transmission to other UEs using the same time and frequency resources as its own, And processes the received signal as shown in FIG.

The UE that has completed the receiving operation in step 455 or step 460 of FIG. 4 resumes the PDCCH blind decoding in step 405.

Table 1 is used to support SU-MIMO and MU-MIMO having the same characteristics as the above-mentioned &quot; system characteristic 1 &quot;. In the LTE-A system, the eNB may actually perform transmission with SU-MIMO and MU-MIMO different from < System characteristics 1 >. Table 2 is used to support SU-MIMO and MU-MIMO having the following characteristics according to the present invention.

<System characteristics 2>

1. SU-MIMO transmission for 1 to 8 layers

2. MU-MIMO transmission that allocates a maximum of 2 layers to one UE

3. MU-MIMO transmission to up to 2 UEs

4. MU-MIMO transmission for up to 4 layers (MU-MIMO composite rank maximum value 4)

When performing coscheduling for up to two UEs at the same time as in the system characteristic 2, the number of DMRS antenna port allocation and interference-related information required to be notified in comparison with Table 1 is relatively reduced. The decrease in the number of cases in this case can be seen by comparing the first column and the second column of Table 2 with the first column and the second column of Table 1.

If the DMRS antenna port is allocated using Table 2, a total of 4 bits of information is required. This is because each column of Table 2 has a maximum of 10 index types. That is, when Table 2 is used, 4 bits of DMRS antenna port allocation and interference related information are transmitted in 230 of FIG.

MU-MIMO (up to two co-scheduled UEs) that allocate up to two layers per UE, and SU-MIMO that allocates up to 8 layers per UE and DMRS antenna port and interference notification method Transport Block 0 Enabled
Transport Block 1 Disabled Transport Block 0 Disabled
Transport Block 1 Enabled Transport Block 0 Enabled
Transport Block 1 Enabled Index Message Index Message Index Message 0 Rank 2 pattern,
DMRS port 0 allocated, DMRS port 1 not used 0 Rank 2 pattern,
DMRS port 1 allocated, DMRS port 0 used by other UE 0 Rank 2 pattern,
DMRS port 0, 1 allocated One Rank 2 pattern,
DMRS port 0 allocated, DMRS port 1 used by other UE One Rank 4 pattern,
DMRS port 2 allocated,
DMRS port 0, 1 used by other UEs,
DMRS port 3 not used One Rank 4 pattern,
DMRS port 0, 1 allocated,
DMRS port 2 used by other UEs,
DMRS port 3 not used 2 Rank 4 pattern,
DMRS port 0 allocated,
DMRS port 2, 3 used by other UEs,
DMRS port 1 not used 2 reserved 2 Rank 4 pattern,
DMRS port 0, 1 allocated,
DMRS port 2, 3 used by other UEs 3 reserved 3 reserved 3 Rank 4 pattern,
DMRS port 2, 3 allocated,
DMRS port 0 used by other UEs,
DMRS port 1 not used 4 reserved 4 reserved 4 Rank 4 pattern,
DMRS port 0, 1, 2 allocated,
DMRS port 3 not used 5 reserved 5 reserved 5 Rank 4 pattern,
DMRS port 0, 1, 2, 3 allocated 6 reserved 6 reserved 6 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4 allocated,
DMRS ports 5, 6, 7 not used 7 reserved 7 reserved 7 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5 allocated
DMRS port 6, 7 not used 8 reserved 8 reserved 8 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5, allocated
DMRS port 7 not used 9 reserved 9 reserved 9 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5, 6, 7 allocated

The method for determining the DMRS antenna port allocation index by the eNB using Table 2 is the same as that of FIG. 3 for Table 1. Also, the method of receiving and analyzing the DMRS antenna port allocation index by the UE is also the same as that of FIG.

Table 3 summarizes the indexes used for notifying the DMRS antenna port information allocated to the UE according to the present invention and the meaning of each index. Table 3 indicates the DMRS antenna port assignment for MIMO transmission, such as < System characteristic 1 >. Table 3 differs from Table 1 in the method of distinguishing the DMRS pattern used for transmitting the DMRS signal and the DMRS signal for each DMRS antenna port. Specifically, in Table 3, a DMRS pattern and a DMRS signal for each DMRS antenna port are separated using a scrambling sequence as described below.

In FIG. 1, when the number of layers transmitted in the MU-MIMO transmission is 3 or 4, the eNB allocates a DMRS signal divided into a frequency domain and a code division to each DMRS antenna port as shown in FIG. In other words, the DMRS antenna port 0 is transmitted as Walsh code 0 (+1, +1) of length 2 in the blue RE region while the DMRS antenna port 3 is transmitted as Walsh code 1 (+1, 1). Table 1 shows the case where the number of layers transmitted in the MU-MIMO transmission is 3 or 4 and the DMRS signal of each DMRS antenna port is discriminated.

When the number of layers transmitted in the MU-MIMO transmission is 3 or 4, another method of distinguishing the DMRS antenna port is to use two scrambling sequences. That is, when the number of layers to be transmitted in the MU-MIMO transmission is 3 or 4, additional red REs are allocated to the red RE region and additional REs are not allocated to the DMRS transmissions. Instead, an additional scrambling sequence is used in the blue RE region, In the MIMO transmission, transmission is performed on up to four DMRS antenna ports. This method is equivalent to defining both the DMRS antenna port 0 and the DMRS antenna port 1 per scrambling sequence using the rank 2 DMRS pattern and using two scrambling sequences. 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 port 0 using scrambling sequence 0 (SC0) and Walsh code 0

2. DMRS antenna port 1 using Scrambling sequence 0 (SC0) and Walsh code 1

3. DMRS antenna port 0 using Walsh code 0 using scrambling sequence 1 (SC1)

4. DMRS antenna port 1 using Scrambling sequence 1 (SC1) and Walsh code 1

When the number of layers transmitted using the MU-MIMO is 3 or 4, DMRS antenna port 0 and DMRS antenna port 1 are arranged for each scrambling sequence. In addition to this method, the above four different cases may be named DMRS antenna port 0, DMRS antenna port 1, DMRS antenna port 2, and DMRS antenna port 3, respectively.

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

Table 3 shows the indexes used to notify the DMRS antenna port information allocated to the UE according to the present invention when the DMRS pattern using two scrambling sequences is used when the composite rank 3 or 4 is transmitted to the MU-MIMO as described above. And what each index means. In Table 3, SC is an abbreviation for the scrambling sequence and it is assumed that the scrambling sequence is always 0 for SU-MIMO transmission.

The indexes used to notify the DMRS antenna port information allocated to the UE in Table 3 according to the present invention and the meanings of the indexes are summarized in Table 1 basically. One difference is that when the composite rank is 3 or 4 without the SU-MIMO and MU-MIMO in Table 1, the signal of the DMRS antenna port is discriminated in the same manner as 110 of FIG. 1, whereas in the case of MU- If the rank is 3 or 4, an additional scrambling sequence is used. In the case of SU-MIMO, the signal of the DMRS antenna port is discriminated in the same manner as 110 of FIG.

The method of determining the DMRS antenna port allocation index by the eNB using Table 3 is the same as that of FIG. Also, the method of receiving and analyzing the DMRS antenna port allocation index by the UE is also the same as that of FIG.

MU-MIMO (up to 4 co-scheduled UE) transmission schemes that allocate up to 2 layers per UE, and SU-MIMO that allocates up to 8 layers per UE and DMRS antenna port and interference notification method 2 Transport Block 0 Enabled
Transport Block 1 Disabled Transport Block 0 Disabled
Transport Block 1 Enabled Transport Block 0 Enabled
Transport Block 1 Enabled Index Message Index Message Index Message 0 Rank 2 pattern,
DMRS port 0 with SC0 allocated,
DMRS port 1 with SC0 and DMRS port 0, 1 with SC1 not used 0 Rank 2 pattern,
DMRS port 1 with SC0 allocated,
DMRS port 0 with SC0 used by other UEs,
DMRS port 0, 1 with SC1 not used 0 Rank 2 pattern,
DMRS port 0, 1 with SC0 allocated,
DMRS port 0, 1 with SC1 not used One Rank 2 pattern,
DMRS port 0 with SC0 allocated,
DMRS port 1 with SC0 used by other UEs,
DMRS port 0, 1 with SC1 not used One Rank 2 pattern,
DMRS port 0 with SC1 allocated,
DMRS port 0, 1 with SC0 used by other UEs,
DMRS port 1 with SC1 not used One Rank 2 pattern,
DMRS port 0, 1 with SC0 allocated,
DMRS port 0 with SC1 used by other UEs,
DMRS port 1 with SC1 not used 2 Rank 2 pattern,
DMRS port 0 with SC0 allocated,
DMRS port 1 with SC0 and DMRS port 0 with SC1 used by other UEs,
DMRS port 1 with SC1 not used 2 Rank 2 pattern,
DMRS port 0 with SC1 allocated,
DMRS port 0, 1 with SC0 and DMRS port 1 with SC1 used by other UEs 2 Rank 4 pattern,
DMRS port 0, 1, 2 with SC0 allocated,
DMRS port 3 with SC0 not used,
DMRS with SC1 not used 3 Rank 2 pattern,
DMRS port 1 with SC0 allocated,
DMRS port 0 with SC0 and DMRS port 0 with SC1 used by other UEs,
DMRS port 1 with SC1 not used 3 Rank 2 pattern,
DMRS port 1 with SC1 allocated,
DMRS port 0, 1 with SC0 and DMRS port 0 with SC1 used by other UEs 3 Rank 2 pattern,
DMRS port 0, 1 with SC0 allocated,
DMRS port 0, 1 with SC1 used by other UEs 4 Rank 2 pattern,
DMRS port 0 with SC0 allocated,
DMRS port 1 with SC0 and DMRS port 0, 1 with SC1 used by other UEs 4 reserved 4 Rank 2 pattern,
DMRS port 0, 1 with SC1 allocated,
DMRS port 0, 1 with SC0 used by other UEs 5 Rank 2 pattern,
DMRS port 1 with SC0 allocated,
DMRS port 0 with SC0 and DMRS port 0, 1 with SC1 used by other UEs 5 reserved 5 Rank 4 pattern,
DMRS port 0, 1, 2, 3 with SC0 allocated,
DMRS with SC1 not used 6 reserved 6 reserved 6 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4 with SC0 allocated,
DMRS port 5, 6, 7 with SC0 not used
DMRS with SC1 not used 7 reserved 7 reserved 7 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5 with SC0 allocated,
DMRS port 6, 7 with SC0 not used
DMRS with SC1 not used 8 reserved 8 reserved 8 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5, 6 with SC0 allocated,
DMRS port 7 with SC0 not used
DMRS with SC1 not used 9 reserved 9 reserved 9 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5, 6, 7 with SC0 allocated,
DMRS with SC1 not used

Table 3 shows the case of transmitting the composite rank 3 and 4 in the MU-MIMO transmission and the scrambling sequence in the rank 2 DMRS pattern to distinguish signals for the four DMRS antenna ports. In this case, another method of distinguishing signals for four DMRS antenna ports is to use orthogonal codes of length 4 for the frequency and time resources corresponding to the rank 2 DMRS pattern. That is, in the case of transmitting the composite rank 3 and 4 in the MU-MIMO transmission, the DMRS is transmitted by allocating one rank 4 orthogonal code to the rank 2 DMRS pattern and one to the DMRS antenna port. Such a case can also be defined as shown in Table 1 and Table 3.

When allocating the DMRS antenna port using Table 3, a total of 4 bits of information is required. This is because each row of Table 3 has a maximum of 10 index types. That is, when Table 3 is used, 4-bit DMRS antenna port allocation and interference related information are transmitted to 230 of FIG.

In the case of Tables 1, 2 and 3, the eNB informs the UE whether it is SU-MIMO or MU-MIMO together with the DMRS antenna port assignment. The present invention also proposes a method of notifying the eNB of SU-MIMO or MU-MIMO transmission with separate information while performing DMRS antenna port allocation and interference notification in LTE-A effectively.

FIG. 6 is a flowchart illustrating a method of transmitting control information for an eNB according to an exemplary embodiment of the present invention. Referring to FIG. 6, a 1-bit control information SU / MU-MIMO indicator for distinguishing whether the transmission of the eNB is SU-MIMO or MU- Respectively.

When the SU / MU-MIMO indicator is used according to the present invention, the eNB informs the scheduled UE of the SU / MU-MIMO indicator value to '0' when its transmission is SU-MIMO transmission. Also, the eNB informs the co-ceded UEs of the SU / MU-MIMO Indicator with a value of '1' when the transmission is an MU-MIMO transmission. According to the present invention, only the transport block 0 is always transmitted when the SU / MU-MIMO indicator is used and the value of the SU / MU-MIMO indicator is '0', that is, SU-MIMO and the number of layers transmitted by the eNB is 1 . If SU-MIMO and the number of layers transmitted by the eNB is 1, only one transport block can be transmitted. In order to reduce the amount of control information for DMRS antenna port allocation, the fixed transport block is always transmitted according to the present invention Because. Also, if the number of layers transmitted by the eNB is 2, 3, 4, 5, 6, 7 or 8, only two transport blocks can be transmitted and the amount of control information for DMRS antenna port assignment is SU-MIMO. Since the fixed transport block 0 is always transmitted according to the present invention.

According to the present invention, when the SU / MU-MIMO indicator is used, the eNB and the UE use two tables according to the value of the SU / MU-MIMO indicator in order to transmit and receive information on the DMRS antenna port allocation and interference.

Table 4 summarizes the indexes used for notifying the DMRS antenna port information allocated to the UE according to the present invention and the meaning of each index when the eNB transmission is SU-MIMO using the SU / MU-MIMO indicator . In Table 4, it is composed of two columns. As compared with Tables 1, 2 and 3, it can be seen that no transport block 0 is transmitted and no corresponding column is transmitted when transport block 1 is transmitted. In Table 4, only the DMRS antenna port allocation information for SU-MIMO is included, and since it is not an MU-MIMO transmission, information related to interference is not included.

Table 5 summarizes the indexes used for notifying the DMRS antenna port information allocated to the UE according to the present invention and the meaning of each index when the eNB transmission uses MU-MIMO using the SU / MU-MIMO indicator . In Table 5, information about the interference signal is included in addition to the information for allocating the DMRS antenna port for each index.

Tables 4 and 5 are designed in accordance with the above <System characteristics 1>.

When using SU / MU-MIMO indicator, DMRS antenna port and interference notification method (for SU-MIMO) Transport Block 0 Enabled
Transport Block 1 Disabled Transport Block 0 Enabled
Transport Block 1 Enabled Index Message Index Message 0 Rank 2 pattern,
DMRS port 0 with SC0 allocated 0 Rank 2 pattern,
DMRS port 0, 1 allocated One reserved One Rank 4 pattern,
DMRS port 0, 1, 2 allocated 2 reserved 2 Rank 4 pattern,
DMRS port 0, 1, 2, 3 allocated 3 reserved 3 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4 allocated 4 reserved 4 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5 allocated 5 reserved 5 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5, allocated 6 reserved 6 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5, 6, 7 allocated

DMRS antenna port and interference notification method (for MU-MIMO) when using SU / MU-MIMO indicator Transport Block 0 Enabled
Transport Block 1 Disabled Transport Block 0 Disabled
Transport Block 1 Enabled Transport Block 0 Enabled
Transport Block 1 Enabled Index Message Index Message Index Message 0 Rank 2 pattern,
DMRS port 0 allocated, DMRS port 1 used by other UE 0 Rank 2 pattern,
DMRS port 1 allocated, DMRS port 0 used by other UE 0 Rank 4 pattern,
DMRS port 0, 1 allocated,
DMRS port 2 used by other UEs,
DMRS port 3 not used One Rank 4 pattern,
DMRS port 0 allocated,
DMRS port 1, 2 used by other UEs,
DMRS port 3 not used One Rank 4 pattern,
DMRS port 2 allocated,
DMRS port 0, 1 used by other UEs,
DMRS port 3 not used One Rank 4 pattern,
DMRS port 0, 1 allocated,
DMRS port 2, 3 used by other UEs 2 Rank 4 pattern,
DMRS port 1 allocated,
DMRS port 0, 2 used by other UEs,
DMRS port 4 not used 2 Rank 4 pattern,
DMRS port 2 allocated,
DMRS ports 0, 1, 3 used by other UEs 2 Rank 4 pattern,
DMRS port 2, 3 allocated,
DMRS port 0, 1 used by other UEs 3 Rank 4 pattern,
DMRS port 0 allocated,
DMRS port 1, 2, 3 used by other UEs 3 Rank 4 pattern,
DMRS port 3 allocated,
DMRS port 0, 1, 2 used by other UEs 3 reserved 4 Rank 4 pattern,
DMRS port 1 allocated,
DMRS ports 0, 2, 3 used by other UEs 4 reserved 4 reserved

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

7 is a diagram illustrating a case where an eNB allocates a DMRS antenna port to a UE when using the SU / MU-MIMO indicator according to an embodiment of the present invention, and a transmission to another UE capable of generating interference in the same frequency and time interval is performed using a DMRS antenna port And the eNB informs whether or not the eNB is used.

In step 705 of FIG. 7, the eNB performs scheduling for specific time and frequency resources. Here, scheduling refers to a process of determining which UE or UEs are to be allocated specific time and frequency resources, and determining a data transmission rate to be transmitted to each UE. In step 705 of FIG. 7, scheduling is performed and the number of UEs to which the eNB is cascaded is set to N. FIG.

In step 710, the eNB determines whether the transmission scheme determined by scheduling is an SU-MIMO transmission or an MU-MIMO transmission. If the value of N determined in step 705 is 1, it corresponds to SU-MIMO, and if N is greater than 1, it corresponds to MU-MIMO. In step 710, when the value of N is 1 (SU-MIMO), the eNB sets the value of the SU / MU-MIMO indicator to '0' in step 715. If the eNB has only one transport block to be transmitted to the SU-MIMO after setting the value of the SU / MU-MIMO indicator in step 715, the eNB sets an index for notifying the DMRS antenna port to be allocated to the UE scheduled in step 725 Select from the first column of 4. If there are two transport blocks transmitted by SU-MIMO, the eNB selects an index for reporting the DMRS antenna port to be allocated to the UE scheduled in step 730, in the second column of Table 4. In step 725 or step 730, the eNB determines an index for notifying the UE of the DMRS antenna port assignment and transmits the 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'.

In step 710 of FIG. 7, if the value of N is greater than 1 (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 step 740, the operation process of the eNB is the same as the process after step 320 of FIG. 3, and a description thereof will be omitted. One difference from the process 320 of FIG. 3 is that the SU / MU-MIMO indicator is set to '1' in the PDCCH transmitted to each UE in step 780 of FIG. In the case of the process 390 of FIG. 3, since the SU / MU-MIMO indicator is not used, this value is not transmitted.

FIG. 8 is a diagram illustrating a case where the UE receives the DMRS antenna port allocation index transmitted by the eNB when the SU / MU-MIMO indicator is used according to the present invention, determines which DMRS antenna port is allocated to itself, Lt; RTI ID = 0.0 &gt; DMRS &lt; / RTI &gt; antenna port that can cause interference to the received signal of the UE.

In step 805 of FIG. 8, the UE performs PDCCH blind decoding. Since the blind decoding in step 805 does not know at what time and frequency interval the PDCCH transmission for the UE itself is performed, decoding is performed on the assumption that transmission is performed in a plurality of candidate time and frequency bands, Only the corresponding decoded control information is used in the LTE and LTE-A systems.

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

In step 820, the UE checks whether the SU / MU-MIMO indicator of the control information included in the PDCCH is set to '0' or '1'. If the SU / MU-MIMO Indicator is '0', it corresponds to SU-MIMO. In step 825, the UE determines whether the eNB has transmitted only transport block 0 or both transport block 0 and transport block 1. If the UE determines in step 825 that only the transport block 0 is received from the eNB, the UE determines in step 830 that the DMRS allocated to the UE through the message in the first column of Table 4 corresponding to the index indicated by the DMRS antenna port allocation control information 640 in FIG. Check the information about the antenna port. The information on the 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 from the UE using the allocated DMRS antenna port, and processes the received signal in the SU-MIMO receiving method in step 840. The SU-MIMO reception method is used in step 840 because the aforementioned SU / MU-MIMO indicator has a value of '0'. If it is determined in step 825 that the UE has transmitted both the transport block 0 and the transport block 1, in step 845, the DMRS allocates the transport block 0 and the transport block 1 through the message in the second column of Table 4 corresponding to the index indicated by the DMRS antenna port allocation control information 640 in FIG. Check the information about the antenna port. The information on the 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 from the UE using the allocated DMRS antenna port, and processes the received signal in the SU-MIMO receiving method in step 850. In this case, as mentioned above, the SU / MU-MIMO indicator has a value of '0'.

In step 820, if the SU / MU-MIMO indicator is set to '1' in the control information on the PDCCH, the UE determines in step 855 whether the eNB has transmitted only the transport block 0 to itself or whether the eNB has transmitted only the transport block 1 , Or whether the eNB has transmitted both transport block 0 and transport block 1 to itself. If the UE determines in step 855 that only the transport block 0 is transmitted, in step 860, the DMRS antenna port allocated through the message in the first column of Table 5 corresponding to the index indicated by the DMRS antenna port allocation control information 640 in FIG. Check information about interference. The UE performs channel estimation for one layer using the allocated DMRS antenna port in step 865 using the allocated DMRS antenna port information obtained in step 860. Then, in step 870, the UE detects a signal on another DMRS antenna port and determines that the received signal is a part of the MU-MIMO transmission, and uses the detected signal to improve the performance of the received signal.

In step 860, when the UE determines that the transport block 1 is transmitted in itself in step 855, the DMRS antenna port allocation information 640 allocated through the message in the second column of Table 5 corresponding to the index indicated by the DMRS antenna port allocation control information 640 in FIG. And information about interference. The UE performs channel estimation for one layer using the allocated DMRS antenna port in step 865 using the allocated DMRS antenna port information obtained in step 875. [ Then, in step 870, the UE detects a signal on another DMRS antenna port and determines that the received signal is a part of the MU-MIMO transmission, and uses the detected signal to improve the performance of the received signal.

If the UE determines in step 855 that both the transport block 0 and the transport block 1 have been transmitted, in step 860, the UE assigns the message in the third column of Table 5 corresponding to the index indicated by the DMRS antenna port allocation control information 640 in FIG. 6 Obtain information on the DMRS antenna port and interference. The UE performs channel estimation for a plurality of layers using the allocated DMRS antenna ports in step 885 using the allocated DMRS antenna port information obtained in step 880. Then, in step 870, the UE detects a signal on another DMRS antenna port and determines that the received signal is a part of the MU-MIMO transmission, and uses the detected signal to improve the performance of the received signal.

The UE that has completed the receiving operation in the process 840 or the process 870 of FIG. 8 resumes the PDCCH blind decoding in the process 805.

In the case of Tables 1, 2, 3, 4, and 5 described above, not only the information on the DMRS antenna port allocated to the UE, which is the scheduling of the eNB, but also whether the transmission is an SU-MIMO transmission or an MU- , It also informs the DMRS antenna port assigned to other UEs that may cause interference. The notification of the DMRS antenna port assigned to the other UE to the scheduling UE enables the UE to perform more accurate interference measurement, thereby improving the reception performance, but there is a disadvantage that additional information must be transmitted.

Accordingly, the present invention provides a method of allocating a DMRS antenna port according to whether a transport block 0 and a transport block 1 are allocated to one UE, and not providing information on interference. This method does not provide information about the interference, which reduces the amount of control information for the allocation of the DMRS antenna port.

Table 6 summarizes the indexes used to notify the DMRS antenna port information allocated to the UE according to the present invention and the meaning of each index. Table 6 shows that, unlike Tables 1, 2, 3, 4, and 5, the eNB can notify only the information about the DMRS antenna port allocated to the UE. Therefore, if Table 6 is used, the eNB can not provide separate information on the interference to the UE even if it performs the MU-MIMO transmission.

Table 6 was designed based on the above <system characteristic 1> and was made on the assumption that the rank 4 DMRS pattern is used when the composite rank is 3 or 4.

The method of notifying the eNB of the DMRS allocated to the UE using Table 6 is similar to that of FIG. 3, so a detailed description will be omitted. The difference between using the method of FIG. 3 and Table 6 is that there is no consideration of interference when the eNB notifies the UE.

In Table 6, each row has a maximum of 9 index types. In Table 1, the maximum number of index types in each column was 10. In Table 6, the number of indexes of each column is reduced because it is not necessary to transmit information on interference, which means that the amount of information to be transmitted is reduced.

MU-MIMO (up to 4 co-scheduled UE) transmission schemes that allocate up to 2 layers per UE, and SU-MIMO that allocates up to 8 layers per UE and DMRS antenna port notification method 1 Transport Block 0 Enabled
Transport Block 1 Disabled Transport Block 0 Disabled
Transport Block 1 Enabled Transport Block 0 Enabled
Transport Block 1 Enabled Index Message Index Message Index Message
0 Rank 2 pattern,
DMRS port 0 allocated 0 Rank 2 pattern,
DMRS port 1 allocated 0 Rank 2 pattern,
DMRS port 0, 1 allocated One Rank 4 pattern,
DMRS port 0 allocated One Rank 4 pattern,
DMRS port 2 allocated One Rank 4 pattern,
DMRS port 0, 1 allocated 2 Rank 4 pattern,
DMRS port 1 allocated 2 Rank 4 pattern,
DMRS port 3 allocated 2 Rank 4 pattern,
DMRS port 2, 3 allocated 3 reserved 3 reserved 3 Rank 4 pattern,
DMRS port 0, 1, 2 allocated 4 reserved 4 reserved 4 Rank 4 pattern,
DMRS port 0, 1, 2, 3 allocated 5 reserved 5 reserved 5 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4 allocated 6 reserved 6 reserved 6 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5 allocated 7 reserved 7 reserved 7 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5, allocated 8 reserved 8 reserved 8 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5, 6, 7 allocated

Table 7 below shows the indexes used for notifying the DMRS antenna port information allocated to the UE according to another embodiment of the present invention and the meaning of each index. Table 7 shows that, unlike Tables 1, 2, 3, 4, and 5, the eNB can notify only the information about the DMRS antenna port allocated to the UE. Therefore, when Table 7 is used, the eNB can not provide separate information on the interference to the UE even when performing the MU-MIMO transmission.

Table 7 is designed based on the above <system information 1>, and assumes that the rank 2 DMRS pattern and the two scrambling sequences are used when the composite rank is 3 or 4. This is the same as in Table 3.

The method of notifying the eNB of the DMRS allocated to the UE using Table 7 is similar to that of FIG. 3, so a detailed description will be omitted. The difference between using the method of FIG. 3 and Table 7 is that there is no consideration for interference when the eNB notifies the UE.

In Table 7, each column has a maximum of 8 index types. In Table 1, the maximum number of index types in each column was 10. Table 7 shows that the number of indexes of each column is reduced because it is not necessary to transmit information on interference, which means that the amount of information to be transmitted is reduced. In case of converting into the number of bits, 4 bits are required to notify the UE of the DMRS antenna port allocation information and interference related information in Table 1. However, when Table 7 is used, the eNB informs the UE of the DMRS antenna port allocation information, .

MU-MIMO (up to 4 co-scheduled UE) transmission schemes that allocate a maximum of 2 layers per UE, and SU-MIMO that allocates up to 8 layers per UE and DMRS antenna port notification method 2 Transport Block 0 Enabled
Transport Block 1 Disabled Transport Block 0 Disabled
Transport Block 1 Enabled Transport Block 0 Enabled
Transport Block 1 Enabled Index Message Index Message Index Message 0 Rank 2 pattern,
DMRS port 0 with SC0 allocated 0 Rank 2 pattern,
DMRS port 1 with SC0 allocated 0 Rank 2 pattern,
DMRS port 0, 1 with SC0 allocated One reserved One Rank 2 pattern,
DMRS port 0 with SC1 allocated One Rank 4 pattern,
DMRS port 0, 1, 2 with SC0 allocated 2 reserved 2 Rank 2 pattern,
DMRS port 1 with SC1 allocated 2 Rank 2 pattern,
DMRS port 0, 1 with SC1 allocated 3 reserved 3 reserved 3 Rank 4 pattern,
DMRS port 0, 1, 2, 3 with SC0 allocated 4 reserved 4 reserved 4 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4 with SC0 allocated 5 reserved 5 reserved 5 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5 with SC0 allocated 6 reserved 6 reserved 6 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5, 6 with SC0 allocated 7 reserved 7 reserved 7 Rank 8 pattern,
DMRS ports 0, 1, 2, 3, 4, 5, 6, 7 with SC0 allocated

In the case of Tables 1 to 7, the eNB is only applied when performing DMRS antenna port assignment for initial transmission in performing HARQ.

Meanwhile, when retransmission is performed in performing the HARQ, it is necessary to be able to perform notifications for cases other than the DMRS antenna port allocation that can be specified in Tables 1 to 7 above.

When automatic HARQ is applied, retransmission is different from initial transmission as follows. In case of initial transmission, if one transport block is transmitted, transmission is performed in one layer. In case of retransmission, even if one transport block is transmitted, it can be transmitted to a plurality of layers according to the judgment of the eNB. In order to notify the UE of the DM-RS antenna port assignment for retransmission, the present invention proposes two methods. The first method is to define additional allocation information for the indexes not used in Tables 1, 2, 3, 4, 5, 6, and 7, which are used to allocate DM-RS antenna ports.

Table 8 is designed in accordance with the above <System Information 1> as in Table 7, and is made on the assumption that the rank 2 DMRS pattern and two scrambling sequences are used when the composite rank is 3 or 4. Table 8 shows that, unlike Tables 1, 2, 3, 4, and 5, the eNB can notify only the information about the DMRS antenna port allocated to the UE. Therefore, when Table 10 is used, the eNB can not provide separate information on the interference to the UE even if it performs the MU-MIMO transmission.

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

1. Even if only one transport block 0 or transport block 1 is transmitted to the UE, it can be freely allocated among four DMRS antenna port and scrambling code combinations. For example, when transmitting one transport block to the UE, the DM-RS antenna port 0 and the scrambling sequence 0, the DM-RS antenna port 1 and the scrambling sequence 0, the DM-RS antenna port 1 and the scrambling sequence 0, And one of the scrambling sequences can be assigned freely. This corresponds to indexes 0, 1, 2, and 3 in the first and second columns of Table x1.

2. An index for additional DM-RS antenna port assignment, which can be applied only in case of retransmission, is defined. These correspond to indices 4, 5, 6, and 7 in the first and second columns of Table 10.

MU-MIMO (up to 4 co-scheduled UE) transmission schemes that allocate a maximum of 2 layers per UE and SU-MIMO that allocates up to 8 layers per UE and DMRS antenna port notification method 3 Transport Block 0 Enabled
Transport Block 1 Disabled Transport Block 0 Disabled
Transport Block 1 Enabled Transport Block 0 Enabled
Transport Block 1 Enabled Index Message Index Message Index Message 0 Rank 2 pattern,
DMRS port 0 with SC0 allocated 0 Rank 2 pattern,
DMRS port 0 with SC0 allocated 0 Rank 2 pattern,
DMRS port 0, 1 with SC0 allocated One Rank 2 pattern,
DMRS port 1 with SC0 allocated One Rank 2 pattern,
DMRS port 1 with SC0 allocated One Rank 4 pattern,
DMRS port 0, 1, 2 with SC0 allocated 2 Rank 2 pattern,
DMRS port 0 with SC1 allocated 2 Rank 2 pattern,
DMRS port 0 with SC1 allocated 2 Rank 2 pattern,
DMRS port 0, 1 with SC1 allocated 3 Rank 2 pattern,
DMRS port 1 with SC1 allocated 3 Rank 2 pattern,
DMRS port 1 with SC1 allocated 3 Rank 4 pattern,
DMRS port 0, 1, 2, 3 with SC0 allocated 4 Rank 2 pattern,
DMRS port 0, 1 with SC0 allocated 4 Rank 2 pattern,
DMRS port 0, 1 with SC0 allocated 4 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4 with SC0 allocated 5 Rank 2 pattern,
DMRS port 0, 1 with SC1 allocated 5 Rank 2 pattern,
DMRS port 0, 1 with SC1 allocated 5 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5 with SC0 allocated 6 Rank 4 pattern,
DMRS port 0, 1, 2 with SC0 allocated 6 Rank 4 pattern,
DMRS port 0, 1, 2 with SC0 allocated 6 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5, 6 with SC0 allocated 7 Rank 4 pattern,
DMRS port 0, 1, 2, 3 with SC0 allocated 7 Rank 4 pattern,
DMRS port 0, 1, 2, 3 with SC0 allocated 7 Rank 8 pattern,
DMRS ports 0, 1, 2, 3, 4, 5, 6, 7 with SC0 allocated

In Table 8, each column has a maximum of 8 index types. In Table 1, the maximum number of index types in each column was 10. In Table 8, each column has 8 indices regardless of the number of transport blocks allocated. Therefore, when allocating the DMRS antenna port using Table 8, 3 bits are required. Although Table 8 is compared with Table 7, it is possible to perform all DM-RS antenna port assignment for initial transmission and retransmission in automatic HARQ, but the number of required bits is 3 as in Table 7 above.

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

In Table 8, the first column and the second column are the same. Therefore, Table 8 can be expressed as shown in Table 9 below. In Table 9, the first column and the second column of Table 8 are integrated into one column, but have the same meaning as a result.

MU-MIMO (up to 4 co-scheduled UE) transmission schemes that allocate a maximum of 2 layers per UE and SU-MIMO that allocates up to 8 layers per UE and DMRS antenna port notification method 3 One of Transport Block 0 or
Transport Block 1 Enabled Transport Block 0 Enabled
Transport Block 1 Enabled Index Message Index Message 0 Rank 2 pattern,
DMRS port 0 with SC0 allocated 0 Rank 2 pattern,
DMRS port 0, 1 with SC0 allocated One Rank 2 pattern,
DMRS port 1 with SC0 allocated One Rank 4 pattern,
DMRS port 0, 1, 2 with SC0 allocated 2 Rank 2 pattern,
DMRS port 0 with SC1 allocated 2 Rank 2 pattern,
DMRS port 0, 1 with SC1 allocated 3 Rank 2 pattern,
DMRS port 1 with SC1 allocated 3 Rank 4 pattern,
DMRS port 0, 1, 2, 3 with SC0 allocated 4 Rank 2 pattern,
DMRS port 0, 1 with SC0 allocated 4 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4 with SC0 allocated 5 Rank 2 pattern,
DMRS port 0, 1 with SC1 allocated 5 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5 with SC0 allocated 6 Rank 4 pattern,
DMRS port 0, 1, 2 with SC0 allocated 6 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5, 6 with SC0 allocated 7 Rank 4 pattern,
DMRS port 0, 1, 2, 3 with SC0 allocated 7 Rank 8 pattern,
DMRS ports 0, 1, 2, 3, 4, 5, 6, 7 with SC0 allocated

FIG. 9 illustrates a method of allocating a DM-RS antenna port by the eNB using Table 8 above. In step 900 of FIG. 9, the eNB performs scheduling of a specific subframe. In step 900, indexes are selected differently depending on whether one transport block or two transport blocks are allocated to a UE scheduled in Table 8. That is, when the UE transmits two transport blocks, the eNB selects an index corresponding to the DM-RS antenna port allocation information in the third column of Table 8, as in step 950. [ When two transport blocks are transmitted to the UE, the index corresponding to the DM-RS antenna port allocation information is selected in the third column of Table 8 regardless of whether the transport blocks to be transmitted are first transmitted or retransmitted.

In FIG. 9, when the eNB transmits one transport block to the UE, the eNB selects indexes differently according to whether the corresponding transport block is first transmitted or retransmitted. In case of the initial transmission, the eNB selects one index except for the indexes 4, 5, 6, and 7 in the first and second columns to determine the DM-RS antenna port allocation information as in step 940. On the other hand, in case of retransmission, the eNB determines the DM-RS antenna port allocation information by selecting one of the indexes of the first and second columns as in step 930.

10 illustrates a method in which the UE interprets a DM-RS antenna port assigned to an eNB using Table 8 above. In step 1000 of FIG. 10, blind decoding of the PDCCH is performed. If it is determined in step 1010 that the PDCCH for the UE has been received, the UE checks the DCI on the PDCCH in step 1020. If it is determined in step 1020 that one transport block is allocated as a result of checking the DCI, the UE determines in step 1040 whether the transmission is an initial transmission or a retransmission. If it is determined in step 1040 that the data is retransmitted, the UE checks the DM-RS antenna port allocated to the UE using the index of the first and second columns of Table 8 and the corresponding DM-RS antenna port allocation information in step 1050 . If it is determined in step 1040 that the initial transmission is to be performed, the UE determines, in step 1060, an index excluding the 4th, 5th, 6th, and 7th indexes in the first and second columns of Table 8 and the corresponding DM- To identify the DM-RS antenna port assigned to it.

In step 1030 of FIG. 10, when the UE receives two transport blocks, the UE transmits DMs allocated to itself using the index of the third column of Table 8 and corresponding DM-RS antenna port allocation information, Check the RS antenna port. If two transport blocks are allocated, it is possible to determine which DM-RS antenna port is allocated without having to determine whether or not to retransmit.

9 and 10, it is possible to determine whether the corresponding transmission is the initial transmission or the retransmission by referring to the NDI (New Data Indicator) bit among the control information transmitted by the eNB. The NDI bit changes when a new initial transmission is made. That is, if the value of the NDI bit is '0' in the nth transmission and the initial transmission is performed in the (n + 1) th transmission, the value of the NDI bit is changed to '1'. On the other hand, in the case of retransmission, the value of the NDI bit remains unchanged.

Tables 8 and 9 can notify the UE of DM-RS antenna port assignment information in initial transmission and retransmission using one table. Another method of expressing Tables 8 and 9 is to separate the initial transmission table and the retransmission table. For example, in the case of the initial transmission in Table 9, it can be divided into the following Tables 10 and 11.

MU-MIMO (up to 4 co-scheduled UE) transmission schemes that allocate up to 2 layers per UE, and SU-MIMO that allocates up to 8 layers per UE and DMRS antenna port notification method 3 For transmission) One of Transport Block 0 or
Transport Block 1 Enabled Transport Block 0 Enabled
Transport Block 1 Enabled Index Message Index Message 0 Rank 2 pattern,
DMRS port 0 with SC0 allocated 0 Rank 2 pattern,
DMRS port 0, 1 with SC0 allocated One Rank 2 pattern,
DMRS port 1 with SC0 allocated One Rank 4 pattern,
DMRS port 0, 1, 2 with SC0 allocated 2 Rank 2 pattern,
DMRS port 0 with SC1 allocated 2 Rank 2 pattern,
DMRS port 0, 1 with SC1 allocated 3 Rank 2 pattern,
DMRS port 1 with SC1 allocated 3 Rank 4 pattern,
DMRS port 0, 1, 2, 3 with SC0 allocated 4 4 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4 with SC0 allocated 5 5 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5 with SC0 allocated 6 6 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5, 6 with SC0 allocated 7 7 Rank 8 pattern,
DMRS ports 0, 1, 2, 3, 4, 5, 6, 7 with SC0 allocated

MU-MIMO (up to 4 co-scheduled UE) transmission schemes that allocate a maximum of 2 layers per UE and SU-MIMO that allocates up to 8 layers per UE and DMRS antenna port notification method 3 (retransmission for) One of Transport Block 0 or
Transport Block 1 Enabled Transport Block 0 Enabled
Transport Block 1 Enabled Index Message Index Message 0 Rank 2 pattern,
DMRS port 0 with SC0 allocated 0 Rank 2 pattern,
DMRS port 0, 1 with SC0 allocated One Rank 2 pattern,
DMRS port 1 with SC0 allocated One Rank 4 pattern,
DMRS port 0, 1, 2 with SC0 allocated 2 Rank 2 pattern,
DMRS port 0 with SC1 allocated 2 Rank 2 pattern,
DMRS port 0, 1 with SC1 allocated 3 Rank 2 pattern,
DMRS port 1 with SC1 allocated 3 Rank 4 pattern,
DMRS port 0, 1, 2, 3 with SC0 allocated 4 Rank 2 pattern,
DMRS port 0, 1 with SC0 allocated 4 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4 with SC0 allocated 5 Rank 2 pattern,
DMRS port 0, 1 with SC1 allocated 5 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5 with SC0 allocated 6 Rank 4 pattern,
DMRS port 0, 1, 2 with SC0 allocated 6 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5, 6 with SC0 allocated 7 Rank 4 pattern,
DMRS port 0, 1, 2, 3 with SC0 allocated 7 Rank 8 pattern,
DMRS ports 0, 1, 2, 3, 4, 5, 6, 7 with SC0 allocated

Tables 8, 9, 10, and 11 are designed in accordance with the system information 1 and are made on the assumption that the rank 2 DMRS pattern and the two scrambling sequences are used when the composite rank is 3 or 4. When the rank 4 DMRS pattern is used when the composite rank is 3 or 4, the indexes used to notify the DM-RS antenna port information as shown in Table 12 and the indexes You can organize the bars.

MU-MIMO (maximum of 4 co-scheduled UE) transmission schemes that allocate a maximum of 2 layers per UE and SU-MIMO that allocates up to 8 layers per UE and DMRS antenna port notification method 4 Transport Block 0 Enabled
Transport Block 1 Disabled Transport Block 0 Disabled
Transport Block 1 Enabled Transport Block 0 Enabled
Transport Block 1 Enabled Index Message Index Message Index Message 0 Rank 2 pattern,
DMRS port 0 with allocated allocated 0 Rank 2 pattern,
DMRS port 0 with allocated allocated 0 Rank 2 pattern,
DMRS port 0, 1 allocated One Rank 2 pattern,
DMRS port 1 with allocated One Rank 2 pattern,
DMRS port 1 with allocated One Rank 4 pattern,
DMRS port 0, 1 allocated 2 Rank 4 pattern,
DMRS port 0 with allocated allocated 2 Rank 4 pattern,
DMRS port 0 with allocated allocated 2 Rank 4 pattern,
DMRS port 2, 3 allocated 3 Rank 4 pattern,
DMRS port 1 with allocated 3 Rank 4 pattern,
DMRS port 1 with allocated 3 Rank 4 pattern,
DMRS port 0, 1, 2 allocated 4 Rank 4 pattern,
DMRS port 2 with allocated 4 Rank 4 pattern,
DMRS port 2 with allocated 4 Rank 4 pattern,
DMRS port 0, 1, 2, 3 allocated 5 Rank 4 pattern,
DMRS port 3 with allocated 5 Rank 4 pattern,
DMRS port 3 with allocated 5 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4 allocated 6 Rank 4 pattern,
DMRS port 0, 1 with allocated 6 Rank 4 pattern,
DMRS port 0, 1 with allocated 6 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5 allocated 7 Rank 4 pattern,
DMRS port 2, 3 with allocated 7 Rank 4 pattern,
DMRS port 2, 3 with allocated 7 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5, allocated 8 Rank 4 pattern,
DMRS port 0, 1, 2 with allocated 8 Rank 4 pattern,
DMRS port 0, 1, 2 with allocated 8 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5, 6, 7 allocated 9 Rank 4 pattern,
DMRS port 0, 1, 2, 3 with allocated 9 Rank 4 pattern,
DMRS port 0, 1, 2, 3 with allocated 9

In Table 12, the index 6, 7, 8, 9 and corresponding DM-RS antenna port assignment messages in the first and second columns are used only for retransmission. That is, in the case of the initial transmission, the DM-RS antenna port assignment is notified only to the index except the indexes 6, 7, 8 and 9 of the first and second columns and the corresponding message.

Table 12 may be expressed by a table having two columns as shown in Table 9 as in Table 8, and may also be represented by tables for initial transmission and retransmission as shown in Table 10 and Table 11. [

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

Table 13 shows the indexes used for notifying the DMRS antenna port information allocated to the UE according to the present invention and the meaning of each index. Table 13 shows DMRS antenna port allocation information and interference related information when the eNB allocates only one transport block allocated to the UE, unlike the case of Tables 1, 2, 3, 4, 5, 6, It is made to be able to do. Table 8 reports the DMRS antenna port assignment for MIMO transmission as follows.

<System Characteristics 3>

1. SU-MIMO transmission for one layer

2. MU-MIMO transmission that assigns up to one layer to one UE

3. MU-MIMO transmission to up to 4 UEs

4. MU-MIMO transmission for up to 4 layers (MU-MIMO composite rank maximum value 4)

DMRS antenna port and interference notification method 1 in the SU and MU-MIMO transmission scheme that transmits a single transport block per UE with a maximum composite rank of 4 Transport Block  0 Enabled
Transport Block 1 Disabled Transport Block 0 Disabled
Transport Block 1 Enabled Index Message Index Message 0 Rank 2 pattern,
DMRS port 0 allocated,
DMRS port 1 not used 0 Rank 2 pattern,
DMRS port 1 allocated,
DMRS port 1 used by other UE One Rank 2 pattern,
DMRS port 0 allocated,
DMRS port 1 used by other UE One Rank 4 pattern,
DMRS port 2 allocated,
DMRS port 0, 1 used by other UE,
DMRS port 3 not used 2 Rank 4 pattern,
DMRS port 0 allocated,
DMRS port 1, 2 used by other UE,
DMRS port 3 not used 2 Rank 4 pattern,
DMRS port 2 allocated,
DMRS ports 0, 1, 3 used by other UE 3 Rank 4 pattern,
DMRS port 1 allocated,
DMRS port 0, 2 used by other UE,
DMRS port 3 not used 3 Rank 4 pattern,
DMRS port 3 allocated,
DMRS port 0, 1, 2 used by other UE 4 Rank 4 pattern,
DMRS port 0 allocated,
DMRS port 1, 2, 3 used by other UE 4 reserved 5 Rank 4 pattern,
DMRS port 1 allocated,
DMRS ports 0, 2, 3 used by other UE 5 reserved

In Table 13, each row has a maximum index of 6. In Table 1, the maximum number of index types in each column was 10. In Table 13, the types of indexes in each column are reduced because the number of transport blocks that can be allocated per UE is limited to one, thereby reducing the number of cases. In case of converting into the number of bits, 4 bits are required to notify the UE about the DMRS antenna port allocation information and the interference related information in Table 1. However, when Table 13 is used, the eNB notifies the DMRS antenna port allocation information and interference related information to the UE It only takes 3 bits.

Table 14 below shows the indexes used for notifying the DMRS antenna port information allocated to the UE according to another embodiment of the present invention and the meaning of each index. Table 14 shows DMRS antenna port allocation information and interference related information when the eNB allocates only one transport block allocated to the UE, unlike the case of Tables 1, 2, 3, 4, 5, 6, It is made to be able to do. Table 1 indicates the DMRS antenna port assignment for MIMO transmission such as < System characteristic 3 >. It is also assumed that the rank 2 DMRS pattern and the two scrambling sequences are used when the composite rank is 3 or 4. This is the same as in Table 3.

In Table 14, each row has a maximum of 6 index types. In Table 1, the maximum number of index types in each column was 10. In Table 14, the types of indexes of each column are reduced because the number of transport blocks that can be allocated per UE is limited to one to reduce the number of cases. 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 Table 14 is used, the eNB notifies the DMRS antenna port allocation information and interference related information to the UE It only takes 3 bits.

In the SU and MU-MIMO transmission schemes with maximum composite rank 4 and one transport block per UE, the DMRS antenna port and the interference notification method 2 Transport Block 0 Enabled
Transport Block 1 Disabled Transport Block 0 Disabled
Transport Block 1 Enabled Index Message Index Message 0 Rank 2 pattern,
DMRS port 0 with SC0 allocated,
DMRS port 1 with SC0 and DMRS port 0, 1 with SC1 not used 0 Rank 2 pattern,
DMRS port 1 with SC0 allocated,
DMRS port 0 with SC0 used by other UE One Rank 2 pattern,
DMRS port 0 with SC0 allocated,
DMRS port 1 with SC0 used by other UE,
DMRS port 0, 1 with SC1 not used One Rank 2 pattern,
DMRS port 0 with SC1 allocated,
DMRS port 0, 1 with SC0 used by other UE,
DMRS port 1 with SC1 not used 2 Rank 2 pattern,
DMRS port 0 with SC0 allocated,
DMRS port 1 with SC0 and DMRS port 0 with SC1 used by other UE,
DMRS port 1 with SC1 not used 2 Rank 2 pattern,
DMRS port 0 with SC1 allocated,
DMRS port 0, 1 with SC0 and DMRS port 1 with SC1 used by other UE 3 Rank 2 pattern,
DMRS port 1 with SC0 allocated,
DMRS port 0 with SC0 and DMRS port 0 with SC1 used by other UE,
DMRS port 1 with SC1 not used 3 Rank 2 pattern,
DMRS port 1 with SC1 allocated,
DMRS port 0, 1 with SC0 and DMRS port 0 with SC1 used by other UE 4 Rank 2 pattern,
DMRS port 0 allocated with SC0,
DMRS port 1 with SC0 and DMRS port 0, 1 with SC1 used by other UE 4 reserved 5 Rank 2 pattern,
DMRS port 1 allocated with SC0,
DMRS port 0 with SC0 and DMRS port 0, 1 with SC1 used by other UE 5 reserved

In the above, a specific DMRS antenna port is referred to in the DMRS antenna port allocation method. For example, if both transport block 0 and transport block 1 are used simultaneously in Table 7, Index 5 uses scrambling code 0 and indicates that DMRS antenna ports 0, 1, 2, 3, 4, and 5 are allocated. The present invention is equally applicable to other combinations of DMRS antenna ports in addition to the combination of the specific DMRS antenna ports mentioned in the above table. For example, if the transmission block 0 and the transmission block 1 are simultaneously used in Table 7, the method of the present invention uses the scrambling code 0 of Index 5 and the DMRS antenna port 0, 1, 2, 3, 4, 5 The DMRS antenna port 0, 1, 2, 5, 6, 7 is allocated instead of the DMRS antenna port.

11 illustrates DMRS antenna port assignment information transmitted from the LTE-A to the PDCCH according to another embodiment of the present invention.

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

Table 15 summarizes the method of indicating the DM-RS port and the transmission method using the NDI bits for the transport block which are not transmitted according to the present invention.

MU-MIMO (up to 4 co-scheduled UE) transmission schemes that allocate up to 2 layers per UE, and SU-MIMO allocating up to 8 layers per UE and DMRS antenna port and transmit diversity notification method One of Transport Block 0 or
Transport Block 1 Enabled Transport Block 0 Enabled
Transport Block 1 Enabled NDI x = 0 NDI x = 1 Index Message Index Message Index Message 0 Transmit Diversity with CRS 0 Rank 2 pattern,
DMRS port 0 with SC0 allocated 0 Rank 2 pattern,
DMRS port 0, 1 with SC0 allocated One Reserved One Rank 2 pattern,
DMRS port 1 with SC0 allocated One Rank 4 pattern,
DMRS port 0, 1, 2 with SC0 allocated 2 Reserved 2 Rank 2 pattern,
DMRS port 0 with SC1 allocated 2 Rank 2 pattern,
DMRS port 0, 1 with SC1 allocated 3 Reserved 3 Rank 2 pattern,
DMRS port 1 with SC1 allocated 3 Rank 4 pattern,
DMRS port 0, 1, 2, 3 with SC0 allocated 4 Reserved 4 Rank 2 pattern,
DMRS port 0, 1 with SC0 allocated 4 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4 with SC0 allocated 5 Reserved 5 Rank 2 pattern,
DMRS port 0, 1 with SC1 allocated 5 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5 with SC0 allocated 6 Reserved 6 Rank 4 pattern,
DMRS port 0, 1, 2 with SC0 allocated 6 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5, 6 with SC0 allocated 7 Reserved 7 Rank 4 pattern,
DMRS port 0, 1, 2, 3 with SC0 allocated 7 Rank 8 pattern,
DMRS ports 0, 1, 2, 3, 4, 5, 6, 7 with SC0 allocated

In Table 15, 'NDI x' is an NDI bit for a transport block that is not transmitted and can be used to notify the UE of the transmission mode of one transport block. In the case of Table 1 through Table 14, only SU-MIMO or MU-MIMO can be notified to the UE. On the other hand, in Table 15, when only one transport block is transmitted, the Node B further notifies the UE whether to use transmit diversity using the NDI bits for the transport block that are not transmitted. The transmit diversity corresponds to the case of using a common reference signal (CRS). Depending on how many antenna ports the CRS has, an SFBC (space frequency block code) or a frequency selective transmit diversity (FSTD) have. That is, when the CRS has two antenna ports, the transmit diversity is automatically set to SFBC. If the CRS has four antenna ports, transmit diversity is automatically set to FSTD + SFBC. On the other hand, when CRS has one antenna port, transmit diversity becomes impossible and it is automatically set to single port transmission.

The transmit diversity in Table 15 corresponds to a case in which only SFBC (space frequency block code) is used, or FSTD (Frequency Selective Transmit Diversity) and SFBC are used in combination. In addition to transmit diversity using CRS in LTE-A systems, transmit diversity using DM-RS is also possible. When DM-RS is used, the following transmit diversity is possible.

1. SFBC with DM-RS antenna port 0, 1

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

Table 16 summarizes another method for indicating the DM-RS port and the transmission method using the NDI bits for the transport block that are not transmitted according to the present invention.

MU-MIMO (up to 4 co-scheduled UE) transmission schemes that allocate up to 2 layers per UE, and SU-MIMO allocating up to 8 layers per UE and DMRS antenna port and transmit diversity notification method 2 One of Transport Block 0 or
Transport Block 1 Enabled Transport Block 0 Enabled
Transport Block 1 Enabled NDI x = 0 NDI x = 1 Index Message Index Message Index Message 0 No Transmit Diversity with DMRS port 0 with SC0 0 Rank 2 pattern,
DMRS port 0 with SC0 allocated 0 Rank 2 pattern,
DMRS port 0, 1 with SC0 allocated One Transmit Diversity with DMRS port 0,1 with SC0 One Rank 2 pattern,
DMRS port 1 with SC0 allocated One Rank 4 pattern,
DMRS port 0, 1, 2 with SC0 allocated 2 Transmit Diversity with DMRS port 0,1,2,3 with SC0 2 Rank 2 pattern,
DMRS port 0 with SC1 allocated 2 Rank 2 pattern,
DMRS port 0, 1 with SC1 allocated 3 Reserved 3 Rank 2 pattern,
DMRS port 1 with SC1 allocated 3 Rank 4 pattern,
DMRS port 0, 1, 2, 3 with SC0 allocated 4 Reserved 4 Rank 2 pattern,
DMRS port 0, 1 with SC0 allocated 4 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4 with SC0 allocated 5 Reserved 5 Rank 2 pattern,
DMRS port 0, 1 with SC1 allocated 5 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5 with SC0 allocated 6 Reserved 6 Rank 4 pattern,
DMRS port 0, 1, 2 with SC0 allocated 6 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5, 6 with SC0 allocated 7 Reserved 7 Rank 4 pattern,
DMRS port 0, 1, 2, 3 with SC0 allocated 7 Rank 8 pattern,
DMRS ports 0, 1, 2, 3, 4, 5, 6, 7 with SC0 allocated

In Table 16, the NDI bit for a transport block that is not transmitted informs the UE whether the transport block to be transmitted is transmitted in transmit diversity and what transmit diversity scheme is to be used.

Table 15 corresponds to a method for notifying transmit diversity using CRS, and Table 16 corresponds to a method for indicating transmit diversity using DM-RS. Another method proposed by the present invention is to enable both transmit diversity using CRS and transmit diversity using DM-RS. If both transmit diversity using CRS and transmit diversity using DM-RS are supported as described above, transmit diversity using CRS and transmit diversity using DM-RS in Table 16 are separately included in Table 15 do.

Table 17 summarizes another method for indicating the DM-RS port and the transmission method using the NDI bits for the transport block which are not transmitted according to the present invention.

In Table 17, the Node B can notify the UE of retransmission, application of transmit diversity, and DM-RS antenna port allocation using the NDI bits for the transport block that are not transmitted. When only one transport block is transmitted, the NDI bit for the transport block that is not transmitted can be used to transmit the transmit diversity to the UE or notify the retransmission when the value is set to '0'. The transmit diversity shown in Table 17 indicates transmit diversity when the value of 'NDI x' for a transport block that is not transmitted is 0 and the index value is 0. The transmit diversity can be applied to both initial transmission or retransmission of HARQ. However, in order to facilitate system design, it can be applied to only one of initial transmission or retransmission of HARQ. For example, if transmit diversity is applicable only to retransmissions, 'NDI x' is a value for determining retransmission.

MU-MIMO (up to 4 co-scheduled UE) transmission schemes that allocate up to 2 layers per UE, and SU-MIMO allocating up to 8 layers per UE and DMRS antenna port and transmit diversity notification method 3 One of Transport Block 0 or
Transport Block 1 Enabled Transport Block 0 Enabled
Transport Block 1 Enabled NDI x = 0 NDI x = 1 Index Message Index Message Index Message 0 Transmit Diversity with CRS (Initial Tx or ReTx) 0 Rank 2 pattern,
DMRS port 0 with SC0 allocated 0 Rank 2 pattern,
DMRS port 0, 1 with SC0 allocated One Rank 2 pattern,
DMRS port 0, 1 with SC0 allocated (Retx) One Rank 2 pattern,
DMRS port 1 with SC0 allocated One Rank 4 pattern,
DMRS port 0, 1, 2 with SC0 allocated 2 Rank 2 pattern,
DMRS port 0, 1 with SC1 allocated (Retx) 2 Rank 2 pattern,
DMRS port 0 with SC1 allocated 2 Rank 2 pattern,
DMRS port 0, 1 with SC1 allocated 3 Rank 4 pattern,
DMRS port 0, 1, 2 with SC0 allocated (Retx) 3 Rank 2 pattern,
DMRS port 1 with SC1 allocated 3 Rank 4 pattern,
DMRS port 0, 1, 2, 3 with SC0 allocated 4 Rank 4 pattern,
DMRS port 0, 1, 2, 3 with SC0 allocated (Retx) 4 Reserved 4 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4 with SC0 allocated 5 Reserved 5 Reserved 5 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5 with SC0 allocated 6 Reserved 6 Reserved 6 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5, 6 with SC0 allocated 7 Reserved 7 Reserved 7 Rank 8 pattern,
DMRS ports 0, 1, 2, 3, 4, 5, 6, 7 with SC0 allocated

Tables 15, 16, and 17 can notify the UE of one of SU-MIMO, MU-MIMO, and transmit diversity using the NDI bits together with the DM-RS port assignment information. Another method proposed by the present invention that utilizes the NDI bits for transport blocks that are not transmitted as described above is to use for notifying synchronous HARQ.

Table 18 summarizes a method of instructing DM-RS port and synchronous HARQ transmission using NDI bits for a transport block not transmitted according to the present invention.

MU-MIMO (up to 4 co-scheduled UE) transmission schemes that allocate up to 2 layers per UE, and SU-MIMO that allocates up to 8 layers per UE and DMRS antenna port and synchronous HARQ notification method One of Transport Block 0 or
Transport Block 1 Enabled Transport Block 0 Enabled
Transport Block 1 Enabled NDI x = 0 NDI x = 1 Index Message Index Message Index Message 0 Rank 2 pattern,
DMRS port 0 with SC0 allocated (Synchronous HARQ) 0 Rank 2 pattern,
DMRS port 0 with SC0 allocated 0 Rank 2 pattern,
DMRS port 0, 1 with SC0 allocated One Rank 2 pattern,
DMRS port 1 with SC0 allocated (Synchronous HARQ) One Rank 2 pattern,
DMRS port 1 with SC0 allocated One Rank 4 pattern,
DMRS port 0, 1, 2 with SC0 allocated 2 Rank 2 pattern,
DMRS port 0 with SC1 allocated (Synchronous HARQ) 2 Rank 2 pattern,
DMRS port 0 with SC1 allocated 2 Rank 2 pattern,
DMRS port 0, 1 with SC1 allocated 3 Rank 2 pattern,
DMRS port 1 with SC1 allocated (Synchronous HARQ) 3 Rank 2 pattern,
DMRS port 1 with SC1 allocated 3 Rank 4 pattern,
DMRS port 0, 1, 2, 3 with SC0 allocated 4 Rank 2 pattern,
DMRS port 0, 1 with SC0 allocated (Synchronous HARQ) 4 Rank 2 pattern,
DMRS port 0, 1 with SC0 allocated 4 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4 with SC0 allocated 5 Rank 2 pattern,
DMRS port 0, 1 with SC1 allocated (Synchronous HARQ) 5 Rank 2 pattern,
DMRS port 0, 1 with SC1 allocated 5 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5 with SC0 allocated 6 Rank 4 pattern,
DMRS port 0, 1, 2 with SC0 allocated (Synchronous HARQ) 6 Rank 4 pattern,
DMRS port 0, 1, 2 with SC0 allocated 6 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5, 6 with SC0 allocated 7 Rank 4 pattern,
DMRS ports 0, 1, 2, 3 with SC0 allocated (Synchronous HARQ) 7 Rank 4 pattern,
DMRS port 0, 1, 2, 3 with SC0 allocated 7 Rank 8 pattern,
DMRS ports 0, 1, 2, 3, 4, 5, 6, 7 with SC0 allocated

In Table 18, the NDI bit for a transport block that is not transmitted notifies the UE whether the transport block to be transmitted is transmitted in the Synchronous HARQ. Since the retransmission of the synchronous HARQ is performed at a constant period, it is not necessary to transmit an additional PDCCH for retransmission. On the other hand, the synchronous HARQ has a disadvantage that it can not adapt to the radio channel change quickly. As shown in Table 18, when one codeword is transmitted, Synchronous HARQ is enabled, so that the Node B and the UE can optimize performance by notifying the UE using the Table 17 when the radio channel environment is suitable for Synchronous HARQ.

Table 19 summarizes another method for instructing the DM-RS port and the synchronous HARQ transmission using the NDI bits for the transport block not transmitted according to the present invention.

MU-MIMO (up to 4 co-scheduled UE) transmission schemes that allocate up to 2 layers per UE, and SU-MIMO that allocates up to 8 layers per UE and DMRS antenna port and synchronous HARQ notification method 2 One of Transport Block 0 or
Transport Block 1 Enabled Transport Block 0 Enabled
Transport Block 1 Enabled NDI x = 0 NDI x = 1 Index Message Index Message Index Message 0 Rank 2 pattern,
DMRS port 0 with SC0 allocated (Synchronous HARQ) 0 Rank 2 pattern,
DMRS port 0 with SC0 allocated 0 Rank 2 pattern,
DMRS port 0, 1 with SC0 allocated One Rank 2 pattern,
DMRS port 1 with SC0 allocated (Synchronous HARQ) One Rank 2 pattern,
DMRS port 1 with SC0 allocated One Rank 4 pattern,
DMRS port 0, 1, 2 with SC0 allocated 2 Rank 2 pattern,
DMRS port 0 with SC1 allocated (Synchronous HARQ) 2 Rank 2 pattern,
DMRS port 0 with SC1 allocated 2 Rank 2 pattern,
DMRS port 0, 1 with SC1 allocated 3 Rank 2 pattern,
DMRS port 1 with SC1 allocated (Synchronous HARQ) 3 Rank 2 pattern,
DMRS port 1 with SC1 allocated 3 Rank 4 pattern,
DMRS port 0, 1, 2, 3 with SC0 allocated 4 Synchronous Transmit Diversity 4 Rank 2 pattern,
DMRS port 0, 1 with SC0 allocated 4 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4 with SC0 allocated 5 Asynchronous Transmit Diversity 5 Rank 2 pattern,
DMRS port 0, 1 with SC1 allocated 5 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5 with SC0 allocated 6 Reserved 6 Rank 4 pattern,
DMRS port 0, 1, 2 with SC0 allocated 6 Rank 8 pattern,
DMRS port 0, 1, 2, 3, 4, 5, 6 with SC0 allocated 7 Reserved 7 Rank 4 pattern,
DMRS port 0, 1, 2, 3 with SC0 allocated 7 Rank 8 pattern,
DMRS ports 0, 1, 2, 3, 4, 5, 6, 7 with SC0 allocated

In the case of Table 19, the Node B transmits to the UE whether or not to transmit the Synchronous HARQ and the transmit diversity using the NDI bits for the transport block that are not transmitted. In the case of Table 19, when the NDI bit for a transport block that is not transmitted is '0', the UE can be notified of Synchronous SU / MU-MIMO or transmit diversity according to the index value. In the case of Table 19 above, the Synchronous HARQ in SU / MU-MIMO is designed to be available only in the initial transmission. This is the result of selecting only the most important transmission schemes considering the limited number of indexes.

FIG. 12 illustrates a process of receiving notification of transmit diversity using NDI bits for transport blocks that are not transmitted in Tables 15 and 16 designed according to the present invention.

The UE receiving the PDCCH in FIG. 12 determines the number of allocated transport blocks in step 1210. If it is determined in step 1210 that two transport blocks have been transmitted, the UE determines in step 1250 which DM-RS antenna port is assigned to itself by using the DMRS allocation indicator information 1150 of FIG. If it is determined in step 1210 that one transport block has been transmitted, the UE determines whether transmit diversity is applied according to a value of an NDI bit for a transport block that is not transmitted. If the value of the NDI bit for the transport block that is not transmitted in step 1220 is '0', the UE determines that the transmit diversity is applied. On the other hand, if the value of the NDI bit for the transport block not transmitted is '1' Or MU-MIMO transmission is performed. The concrete transmission information of FIG. 12 is determined by Tables 15 and 16 above.

FIG. 13 shows a process of notifying whether retransmission, initial transmission, and transmit diversity are applied using NDI bits for transport blocks that are not transmitted in Table 17 designed according to the present invention.

In step 1310, the UE receiving the PDCCH determines the number of allocated transport blocks. If it is determined in step 1310 that two transport blocks are transmitted, the UE determines in step 1350 which DM-RS antenna port has been allocated to itself using the DMRS allocation indicator information 1150 of FIG. If it is determined in step 1310 that one transport block has been transmitted, the UE determines whether it is an initial transmission or retransmission according to the value of an NDI bit for a transport block that is not transmitted. If the value of the NDI bit for the transport block that is not transmitted in step 1320 is '0', the UE determines that the retransmission has been performed. If the value of the NDI bit for the transport block that is not transmitted is '1' . Also, if it is determined that one transport block is transmitted and the value of the NDI bit for the transport block that is not transmitted is '0', the UE is notified of the application of transmit diversity according to the DM-RS allocation indicator information 1150. The concrete delivery information of FIG. 13 is determined according to Table 17 above.

FIG. 14 illustrates a process for notifying whether adaptive HARQ is applied using NDI bits for transport blocks that are not transmitted in Table 18 designed according to the present invention.

In step 1410, the UE receiving the PDCCH determines the number of allocated transport blocks. If it is determined in step 1410 that two transport blocks have been transmitted, the UE determines in step 1450 which DM-RS antenna port is assigned to itself by using the DMRS allocation indicator information 1150 of FIG. If it is determined in step 1410 that one transport block has been transmitted, the UE determines whether the synchronous HARQ is applied according to the value of the NDI bit for the transport block that is not transmitted. If the value of the NDI bit for the transport block not transmitted in step 1420 is '0', the UE determines that the synchronous HARQ is applied. Conversely, if the value of the NDI bit for the transport block not transmitted is '1' It is judged to have been applied. The concrete delivery information of FIG. 14 is determined according to Table 18 above.

The method of indicating whether or not to transmit the Synchronous HARQ corresponds to a downlink direction in which a BS transmits to a UE. The method of indicating whether or not to transmit the synchronous HARQ can be applied to the uplink direction in which the terminal transmits to the base station.

Claims (28)

A method for analyzing control information of a terminal in a wireless communication system,
The method comprising: receiving control information including transport block information and reference signal antenna port allocation indication information indicating up to eight antenna ports;
Checking the number of transport blocks allocated to the UE based on the transport block information; And
And analyzing the reference signal antenna port allocation indication information according to the number of transmission blocks allocated to the UE,
The length of the reference signal antenna port allocation indication information is 3 bits,
Wherein the reference signal antenna port allocation indication information is used for data demodulation. The method according to claim 1,
When one transmission block is enabled, the reference signal antenna port allocation indication information is set to indicate up to four antenna ports for four layers,
The reference signal for one layer includes information about a combination of 0 or 1 and a first antenna port or a second antenna port,
A reference signal for the two layers includes information about the first antenna port and the second antenna port,
The reference signals for the three layers include information about the first antenna port, the second antenna port, and the third antenna port,
Wherein the reference signal for the four layers includes information on the first antenna port, the second antenna port, the third antenna port, and the fourth antenna port. . The method according to claim 1,
Wherein the control information includes indication information for notifying whether the number of other terminals allocated to at least one layer transmitted from the base station is equal to or greater than 1. The method of claim 1, The method according to claim 1,
When two transmission blocks are enabled, the reference signal antenna port allocation indication information is set to indicate up to eight antenna ports for eight layers,
The reference signal for the two layers includes information about a scrambling sequence 0 or 1, a combination of a first antenna port and a second antenna port,
Wherein the reference signal for the N layers includes information on the first antenna port to the Nth antenna port. The method according to claim 1,
If one transport block is enabled and the one transport block is transmitted through two, three, or four layers, the reference signal for two, three, or four layers is used only for retransmission of the one transport block Wherein the control information is transmitted to the terminal. 6. The method of claim 5,
If the one transport block is enabled and the one transport block is transmitted through the two layers, the reference signal for the two layers is used for retransmission of the one transport block,
If the one transport block is transmitted through the three layers, the reference signal for the three layers is used only for retransmission of the one transport block,
Wherein if the one transport block is transmitted through the four layers, the reference signal for the four layers is used only for retransmission of the one transport block in the wireless communication system. The method according to claim 1,
The reference signal antenna port assignment indication information includes:
When the number of the transmission blocks is 1, a reference signal antenna port 0 designation index assigned to a scrambling code 0 of a rank pattern 2, a reference signal antenna port 0 assigned to a scrambling code 0 of a rank pattern 2, Allocated to the reference signal antenna port 0 instruction index assigned to scrambling code 1 of 1 instruction index, rank pattern 2, reference signal antenna port 1 instruction index assigned to scrambling code 1 of rank pattern 2, scrambling code 0 assigned to scrambling code 0 of rank pattern 2 Reference signal antenna port 0 and 1 reference index assigned to scrambling code 0 of rank pattern 4, reference signal antenna port 0, 1 and 2 index index, reference signal assigned to scrambling code 0 of rank pattern 4 0, 1, 2, and 3 instruction indices,
The reference signal antenna port 0 assigned to the scrambling code 0 of the rank pattern 2 and the reference signal antenna port 0, 1 and 2 assigned to the 1 index, the scrambling code 0 of the rank pattern 4, The reference signal antenna port 0 assigned to the scrambling code 1 of the rank pattern 2, and the reference index antenna port 0, 1, 2 and 3 assigned to the scrambling code 0 of the index index 1 and the rank pattern 4, Reference signals assigned to scrambling code 0 Antenna ports 0, 1, 2, 3 and 4 Instruction indexes, reference signal assigned to scrambling code 0 of rank pattern 8 Antenna ports 0, 1, 2, 3, 4 and 5 Instruction index, 1, 2, 3, 4, 5 and 6 reference signals assigned to the scrambling code 0 of the rank pattern 8, and reference signal antenna ports 0, 1, 2, 3 allocated to the scrambling code 0 of the index index, rank pattern 8, 3, 4, 5, 6, and 7 of the instruction index And even including one,
Wherein the reference signal antenna port 0 corresponds to a first antenna port allocated to a reference signal and the reference signal antenna port n is indexed in ascending order from a reference signal antenna port 0. In the wireless communication system, Interpretation method. A method for transmitting control information of a base station in a wireless communication system,
Deriving a number of transport blocks allocated to a terminal from a base station;
Selecting reference signal antenna port allocation indication information indicating up to eight antenna ports according to the number of transmission blocks allocated to the UE;
Generating control information including transmission block information indicating the number of transmission blocks and reference signal antenna port allocation indication information; And
And transmitting the control information to the terminal,
The length of the reference signal antenna port allocation indication information is 3 bits,
Wherein the reference signal antenna port allocation indication information is used for data demodulation. 9. The method of claim 8,
Wherein the control information includes indication information for notifying whether the number of other terminals allocated to at least one layer transmitted from the base station is equal to or greater than one. 9. The method of claim 8,
When one transmission block is enabled, the reference signal antenna port allocation indication information is set to indicate up to four antenna ports for four layers,
The reference signal for one layer includes information about a combination of 0 or 1 and a first antenna port or a second antenna port,
A reference signal for the two layers includes information about the first antenna port and the second antenna port,
The reference signals for the three layers include information about the first antenna port, the second antenna port, and the third antenna port,
Wherein the reference signal for the four layers includes information on the first antenna port, the second antenna port, the third antenna port, and the fourth antenna port in the wireless communication system. . 9. The method of claim 8,
When two transmission blocks are enabled, the reference signal antenna port allocation indication information is set to indicate up to eight antenna ports for eight layers,
The reference signal for the two layers includes a scrambling sequence 0 or 1 and information about a combination of the first antenna port and the second antenna port,
Wherein the reference signal for the N layers includes information on the first antenna port to the Nth antenna port. 9. The method of claim 8,
If one transmission block is enabled and the one transmission block is transmitted through 2, 3 or 4 layers, a reference signal for 2, 3 or 4 layers is used for retransmission of the one transmission block. And transmitting the control information to the base station. 13. The method of claim 12,
If the one transport block is enabled and the one transport block is transmitted through the two layers, the reference signal for the two layers is used for retransmission of the one transport block,
If the one transport block is transmitted through the three layers, the reference signal for the three layers is used only for retransmission of the one transport block,
Wherein if the one transport block is transmitted through the four layers, the reference signal for the four layers is used only for retransmission of the one transport block. 9. The method of claim 8,
The reference signal antenna port assignment indication information includes:
When the number of the transmission blocks is 1, a reference signal antenna port 0 designation index assigned to a scrambling code 0 of a rank pattern 2, a reference signal antenna port 0 assigned to a scrambling code 0 of a rank pattern 2, Allocated to the reference signal antenna port 0 instruction index assigned to scrambling code 1 of 1 instruction index, rank pattern 2, reference signal antenna port 1 instruction index assigned to scrambling code 1 of rank pattern 2, scrambling code 0 assigned to scrambling code 0 of rank pattern 2 Reference signal antenna port 0 and 1 reference index assigned to scrambling code 0 of rank pattern 4, reference signal antenna port 0, 1 and 2 index index, reference signal assigned to scrambling code 0 of rank pattern 4 0, 1, 2, and 3 instruction indices,
The reference signal antenna port 0 assigned to the scrambling code 0 of the rank pattern 2 and the reference signal antenna port 0, 1 and 2 assigned to the 1 index, the scrambling code 0 of the rank pattern 4, The reference signal antenna port 0 assigned to the scrambling code 1 of the rank pattern 2, and the reference index antenna port 0, 1, 2 and 3 assigned to the scrambling code 0 of the index index 1 and the rank pattern 4, Reference signals assigned to scrambling code 0 Antenna ports 0, 1, 2, 3 and 4 Instruction indexes, reference signal assigned to scrambling code 0 of rank pattern 8 Antenna ports 0, 1, 2, 3, 4 and 5 Instruction index, 1, 2, 3, 4, 5 and 6 reference signals assigned to the scrambling code 0 of the rank pattern 8, and reference signal antenna ports 0, 1, 2, 3 allocated to the scrambling code 0 of the index index, rank pattern 8, 3, 4, 5, 6, and 7 of the instruction index And even including one,
Wherein the reference signal antenna port 0 corresponds to a first antenna port assigned to a reference signal and an arbitrary reference signal antenna port n is indexed in ascending order from a reference signal antenna port 0. In the wireless communication system, Transmission method. A terminal for receiving and analyzing control information from a base station in a wireless communication system,
A wireless communication unit for receiving control information including transport block information and reference signal antenna port allocation indication information indicating up to eight antenna ports;
And a controller for checking the number of transport blocks allocated to the UE based on the transport block information and analyzing the reference signal antenna port allocation indication information according to the number of transport blocks allocated to the UE,
The length of the reference signal antenna port allocation indication information is 3 bits,
Wherein the reference signal antenna port assignment indication information is used for data demodulation. 16. The method of claim 15,
Wherein the control information includes indication information for indicating whether or not the number of other terminals allocated to at least one layer transmitted from the base station is equal to or greater than one. 16. The method of claim 15,
When one transmission block is enabled, the reference signal antenna port allocation indication information is set to indicate up to four antenna ports for four layers,
The reference signal for one layer includes information about a combination of 0 or 1 and a first antenna port or a second antenna port,
A reference signal for the two layers includes information about the first antenna port and the second antenna port,
The reference signals for the three layers include information about the first antenna port, the second antenna port, and the third antenna port,
Wherein the reference signal for the four layers includes information about the first antenna port, the second antenna port, the third antenna port, and the fourth antenna port. 16. The method of claim 15,
When two transport blocks are enabled, the reference signal antenna port allocation indication information is set to indicate up to eight antenna ports for eight layers,
The reference signal for the two layers includes a scrambling sequence 0 or 1 and information about a combination of the first antenna port and the second antenna port,
And the reference signal for the N layers includes information on the first antenna port to the Nth antenna port. 16. The method of claim 15,
If one transport block is enabled and the one transport block is transmitted through two, three, or four layers, the control unit uses only the reference signals for two, three, or four layers for retransmission of the one transport block Wherein the terminal is a mobile terminal. 20. The method of claim 19,
If the one transport block is enabled and the one transport block is transmitted through the two layers, the reference signal for the two layers is used for retransmission of the one transport block,
If the one transport block is transmitted through the three layers, the reference signal for the three layers is used only for retransmission of the one transport block,
Wherein if the one transport block is transmitted through the four layers, the reference signal for the four layers is used only for retransmission of the one transport block. 16. The method of claim 15,
The reference signal antenna port assignment indication information includes:
When the number of the transmission blocks is 1, a reference signal antenna port 0 designation index assigned to a scrambling code 0 of a rank pattern 2, a reference signal antenna port 0 assigned to a scrambling code 0 of a rank pattern 2, Allocated to the reference signal antenna port 0 instruction index assigned to scrambling code 1 of 1 instruction index, rank pattern 2, reference signal antenna port 1 instruction index assigned to scrambling code 1 of rank pattern 2, scrambling code 0 assigned to scrambling code 0 of rank pattern 2 Reference signal antenna port 0 and 1 reference index assigned to scrambling code 0 of rank pattern 4, reference signal antenna port 0, 1 and 2 index index, reference signal assigned to scrambling code 0 of rank pattern 4 0, 1, 2, and 3 instruction indices,
The reference signal antenna port 0 assigned to the scrambling code 0 of the rank pattern 2 and the reference signal antenna port 0, 1 and 2 assigned to the 1 index, the scrambling code 0 of the rank pattern 4, The reference signal antenna port 0 assigned to the scrambling code 1 of the rank pattern 2, and the reference index antenna port 0, 1, 2 and 3 assigned to the scrambling code 0 of the index index 1 and the rank pattern 4, Reference signals assigned to scrambling code 0 Antenna ports 0, 1, 2, 3 and 4 Instruction indexes, reference signal assigned to scrambling code 0 of rank pattern 8 Antenna ports 0, 1, 2, 3, 4 and 5 Instruction index, 1, 2, 3, 4, 5 and 6 reference signals assigned to the scrambling code 0 of the rank pattern 8, and reference signal antenna ports 0, 1, 2, 3 allocated to the scrambling code 0 of the index index, rank pattern 8, 3, 4, 5, 6, and 7 of the instruction index And even including one,
Wherein the reference signal antenna port 0 corresponds to the first antenna port allocated to the reference signal and the reference signal antenna port n is indexed from the reference signal antenna port 0 in ascending order. A base station for transmitting control information in a wireless communication system,
Selects the reference signal antenna port allocation indication information indicating up to 8 antenna ports according to the number of the transport blocks allocated to the terminal, A control unit for generating control information including transmission block information indicating the number of transmission antennas and the reference signal antenna port allocation indication information; And
And a wireless communication unit for transmitting the control information to the terminal,
The length of the reference signal antenna port allocation indication information is 3 bits,
Wherein the reference signal antenna port allocation indication information is used for data demodulation. 23. The method of claim 22,
Wherein the control information includes indication information for notifying whether the number of other terminals allocated to at least one layer transmitted from the base station is equal to or greater than one. 23. The method of claim 22,
When one transmission block is enabled, the reference signal antenna port allocation indication information is set to indicate up to four antenna ports for four layers,
The reference signal for one layer includes information about a combination of 0 or 1 and a first antenna port or a second antenna port,
A reference signal for the two layers includes information about the first antenna port and the second antenna port,
The reference signals for the three layers include information about the first antenna port, the second antenna port, and the third antenna port,
Wherein the reference signal for the four layers includes information about the first antenna port, the second antenna port, the third antenna port, and the fourth antenna port. 23. The method of claim 22,
When two transmission blocks are enabled, the reference signal antenna port allocation indication information is set to indicate up to eight antenna ports for eight layers,
The reference signal for the two layers includes a scrambling sequence 0 or 1 and information about a combination of the first antenna port and the second antenna port,
Wherein the reference signal for the N layers includes information about the first antenna port to the Nth antenna port. 23. The method of claim 22,
If one transport block is enabled and the one transport block is transmitted via 2, 3 or 4 layers, interpretation that the reference signal for 2, 3 or 4 layers is used only for retransmission of the one transport block Characterized in that the base station. 27. The method of claim 26,
If the one transport block is enabled and the one transport block is transmitted through the two layers, the reference signal for the two layers is used for retransmission of the one transport block,
If the one transport block is transmitted through the three layers, the reference signal for the three layers is used only for retransmission of the one transport block,
Wherein if the one transport block is transmitted through the four layers, the reference signal for the four layers is used only for retransmission of the one transport block. 23. The method of claim 22,
The reference signal antenna port assignment indication information includes:
When the number of the transmission blocks is 1, a reference signal antenna port 0 designation index assigned to a scrambling code 0 of a rank pattern 2, a reference signal antenna port 0 assigned to a scrambling code 0 of a rank pattern 2, Allocated to the reference signal antenna port 0 instruction index assigned to scrambling code 1 of 1 instruction index, rank pattern 2, reference signal antenna port 1 instruction index assigned to scrambling code 1 of rank pattern 2, scrambling code 0 assigned to scrambling code 0 of rank pattern 2 Reference signal antenna port 0 and 1 reference index assigned to scrambling code 0 of rank pattern 4, reference signal antenna port 0, 1 and 2 index index, reference signal assigned to scrambling code 0 of rank pattern 4 0, 1, 2, and 3 instruction indices,
The reference signal antenna port 0 assigned to the scrambling code 0 of the rank pattern 2 and the reference signal antenna port 0, 1 and 2 assigned to the 1 index, the scrambling code 0 of the rank pattern 4, The reference signal antenna port 0 assigned to the scrambling code 1 of the rank pattern 2, and the reference index antenna port 0, 1, 2 and 3 assigned to the scrambling code 0 of the index index 1 and the rank pattern 4, Reference signals assigned to scrambling code 0 Antenna ports 0, 1, 2, 3 and 4 Instruction indexes, reference signal assigned to scrambling code 0 of rank pattern 8 Antenna ports 0, 1, 2, 3, 4 and 5 Instruction index, 1, 2, 3, 4, 5 and 6 reference signals assigned to the scrambling code 0 of the rank pattern 8, and reference signal antenna ports 0, 1, 2, 3 allocated to the scrambling code 0 of the index index, rank pattern 8, 3, 4, 5, 6, and 7 of the instruction index And even including one,
Wherein the reference signal antenna port 0 corresponds to the first antenna port allocated to the reference signal and the reference signal antenna port n is indexed in ascending order from the reference signal antenna port 0. [

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