KR20160121367A - Apparatus and method of transmitting reference signal in multi-dimension multiple antenna system - Google Patents
Apparatus and method of transmitting reference signal in multi-dimension multiple antenna system Download PDFInfo
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/0413—MIMO systems
- H04B7/0456—Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
- H04B7/046—Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting taking physical layer constraints into account
- H04B7/0473—Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting taking physical layer constraints into account taking constraints in layer or codeword to antenna mapping into account
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/0413—MIMO systems
- H04B7/0452—Multi-user MIMO systems
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/0202—Channel estimation
- H04L25/0224—Channel estimation using sounding signals
Abstract
A device and method for transmitting a reference signal in a multi-dimensional multi-antenna system are disclosed.
The method includes generating a reference signal sequence to be used in a resource configuration for a DM-RS, generating a modulation symbol of a demodulation value by multiplying the reference signal sequence by an orthogonal sequence defined for each antenna port, Transmitting the DM-RS to a terminal, transmitting selection information on a table used for indicating an antenna port, a scrambling identifier, and a number of layers to the terminal, and transmitting an antenna port, a scrambling identifier, And transmitting indication information indicating an identifier and a number of layers to the terminal.
Description
BACKGROUND OF THE
The diversification and increase of wireless communication devices are dramatically increasing the data traffic of the wireless network. Multiple input multiple output (MIMO) is being used as a key technology to meet increasing traffic capacity requirements. The currently commercialized wireless communication system implements MIMO as an antenna arranged in an azimuth dimension. In recent years, a method of arranging a two-dimensional active antenna array on an elevation dimension as well as an azimuth dimension has been considered. The MIMO considered as an altitude dimension as well as the azimuth dimension can be referred to as a multidimensional MIMO or a 3D (3-Dimensional) -MIMO or a FD (Full-Dimensional) -MIMO. Multidimensional MIMO with a 2D antenna array is possible to provide an additional spatial degree of freedom in the elevation dimension by a large number of spatially multiplexed terminals using the same time-frequency resources. In other words, multidimensional MIMO can potentially support higher dimensional multi-user (MU) MIMO.
In the MIMO system, several reference signals (RSs) are used for channel estimation. Among them, there is a demodulation reference signal (DeModulation RS: DM-RS) for demodulating data. The maximum number of layers per UE and the maximum number of layers in the MU-MIMO are considered in order to improve the performance of the DM-RS. This is the most important factor for improving the performance of DM-RS. As described above, since the multidimensional MIMO system can support the additional spatial freedom and higher-level MU-MIMO, it is necessary to increase the number of layers for DM-RS.
The present invention also provides an apparatus and method for transmitting a reference signal in a multi-dimensional multi-antenna system.
It is another object of the present invention to provide an apparatus and method for receiving a reference signal in a multi-dimensional multi-antenna system.
Another aspect of the present invention is to provide a method of mapping a DM-RS layer and an antenna port to a multidimensional MIMO system supporting an increased number of layers.
Another aspect of the present invention is to provide a method of constructing a table indicating an antenna port, a scrambling identifier, and a number of layers for a multidimensional MIMO system supporting an increased number of layers.
Another aspect of the present invention is to provide an apparatus and method for identifying a table indicating an antenna port, a scrambling identifier, and a number of layers for a multidimensional MIMO system supporting an increased number of layers.
According to an aspect of the present invention, there is provided a method of transmitting a demodulation-reference signal (DM-RS) by a base station in a wireless communication system supporting multiple antennas. The method includes generating a reference signal sequence to be used in a resource configuration for a DM-RS, multiplying the reference signal sequence by an orthogonal sequence defined for each antenna port to generate a modulation symbol of a demodulation value, transmitting the DM-RS to a terminal, selecting information on a table used for indicating an antenna port, a scrambling identifier, and a number of layers, And transmitting indication information indicating a port, a scrambling identifier, and a number of layers to the terminal.
In this case, when the communication is performed based on a multi-user MIMO (Multi-User Multiple Input Multiple Output) supporting only two layers per terminal, the table shows an antenna port having an antenna port number of 9 or more to each layer You can map.
Meanwhile, the selection information may be included in the downlink control information and transmitted as one bit.
In another aspect, the selection information may be transmitted as one bit in a radio resource control (RRC) message.
In yet another aspect, the selection information may indicate any one of two tables.
In another aspect, in precoding for the DM-RS, layers with
The method and apparatus proposed in the present invention are advantageous in that the UE and the BS can more efficiently perform downlink DM-RS transmission and reception in a multi-dimensional MIMO (3D-MIMO or FD-MIMO) environment, respectively.
1 is a block diagram illustrating a wireless communication system to which the present invention is applied.
2 and 3 schematically show the structure of a radio frame to which the present invention is applied.
4 is an operation example of a multi-dimensional MIMO system to which the present invention is applied.
FIG. 5 is a diagram illustrating a pattern in which a DM-RS according to an embodiment is mapped to 12 resource elements and 2 antenna ports.
FIG. 6 is a diagram illustrating a pattern in which a DM-RS according to another embodiment is mapped to 24 resource elements and 8 antenna ports.
7 is an example in which the DM-RS according to another embodiment is mapped to 12 resource elements, 4 antenna ports, and an orthogonal sequence length = 4.
8 is an example in which a DM-RS according to another embodiment is mapped to 24 resource elements, 4 antenna ports, and orthogonal sequence length = 2.
9 is a flowchart illustrating a DM-RS transmission / reception method between a terminal and a base station according to an exemplary embodiment of the present invention.
10 is a block diagram illustrating a wireless communication system including a terminal and a base station according to an embodiment of the present invention.
Hereinafter, some embodiments will be described in detail with reference to exemplary drawings. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference symbols as possible even if they are shown in different drawings. In the following description of the embodiments of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present disclosure rather unclear.
The present invention will be described with reference to a communication network. The work performed in the communication network may be performed in a process of controlling the network and transmitting data by a system (e.g., a base station) that manages the communication network, The work can be done.
1 is a block diagram illustrating a wireless communication system to which the present invention is applied.
Referring to FIG. 1, a
A mobile station (MS) 12 may be fixed or mobile and may be a user equipment (UE), a mobile terminal (MT), a user terminal (UT), a subscriber station (SS), a wireless device, (personal digital assistant), a wireless modem, a handheld device, and the like. The
Hereinafter, a downlink refers to a communication or communication path from the
The layers of the radio interface protocol between the terminal and the base station are divided into a first layer (L1), a second layer (L1), and a second layer (L2) based on the lower three layers of an Open System Interconnection A second layer (L2), and a third layer (L3). Among them, there are several physical channels used in the physical layer belonging to the first layer. The physical downlink control channel (PDCCH) includes a resource allocation and transmission format of a downlink shared channel (DL-SCH), a resource of an uplink shared channel (UL-SCH) Resource allocation of an upper layer control message such as allocation information, a random access response transmitted on a physical downlink shared channel (PDSCH), transmission power control for individual terminals in an arbitrary terminal group : TPC) commands, and so on. A plurality of PDCCHs can be transmitted in the control domain, and the UE can monitor a plurality of PDCCHs. The control information of the physical layer mapped to the PDCCH is referred to as downlink control information (DCI). That is, the DCI is transmitted on the PDCCH.
2 and 3 schematically show the structure of a radio frame to which the present invention is applied.
Referring to FIGS. 2 and 3, a radio frame includes 10 subframes. One subframe includes two slots. The time (length) for transmitting one subframe is called a transmission time interval (TTI). Referring to FIG. 2, for example, the length of one subframe (1 subframe) may be 1 ms and the length of one slot may be 0.5 ms.
A slot may contain a plurality of symbols in the time domain. For example, in the case of a radio system using OFDMA (Downlink Frequency Division Multiple Access) in a downlink (DL), the symbol may be an Orthogonal Frequency Division Multiplexing (OFDM) symbol. On the other hand, the representation of the symbol period of the time domain is not limited by the multiple access scheme or the name. For example, in a time domain, a plurality of symbols may be a single-carrier-frequency division multiple access (SC-FDMA) symbol, a symbol period, etc. in addition to an OFDM symbol.
The number of OFDM symbols included in one slot may vary according to the length of a CP (Cyclic Prefix). For example, one slot includes seven OFDM symbols in case of a normal CP, and one slot may include six OFDM symbols in case of an extended CP.
A resource block (RB) is a resource allocation unit, which includes time-frequency resources corresponding to 180 kHz on the frequency axis and 1 slot on the time axis. A resource element (RE) represents a smallest time-frequency unit to which a modulation symbol of a data channel or a modulation symbol of a control channel is mapped.
4 is an operation example of a multi-dimensional MIMO system to which the present invention is applied.
Referring to FIG. 4, the beamforming performed by the two-dimensional antenna array may proceed in two directions. One is beamforming in the azimuth direction and the other is the beamforming in the elevation direction.
In a wireless communication system including a multidimensional MIMO system, it is necessary to estimate an uplink channel or a downlink channel for data transmission / reception, system synchronization acquisition, channel information feedback, and the like. A process of compensating for a distortion of a signal caused by a sudden change in channel environment and restoring a transmission signal is called channel estimation. It is also necessary to measure the channel state of the cell or other cell to which the terminal belongs. In general, a reference signal (RS) known between a UE and a transmission / reception point is used for channel estimation or channel state measurement.
Since the UE knows the information of the reference signal, the UE estimates the channel based on the received reference signal, compensates the channel value, and can accurately obtain the data transmitted from the base station. If the reference signal sent from the base station is p, the channel information experienced by the reference signal during transmission is h, the thermal noise generated by the terminal is n, and the signal received by the terminal is y, y = h p + n . Since the reference signal p is already known by the UE, if the LS (Least Square) scheme is used, the channel information
Here, the channel estimation value estimated using the reference signal p
The downlink reference signal includes a cell-specific RS, a MBSFN reference signal, a UE-specific RS, a position reference signal PRS, RS) and a CSI (Channel State Information) reference signal (CSI-RS). The UE-specific reference signal is a reference signal received by a specific UE or a specific UE group in a cell and can be called a Demodulation RS (DM-RS) since it is mainly used for data demodulation of a specific UE or a specific UE group. have.
For a DM-RS used in a multi-dimensional MIMO system, the number of resource elements to which a DM-RS is mapped, the number of orthogonal sequences to provide orthogonality between DM-RSs in the same resource element, According to the number of scrambling code IDs (SCIDs), which is a parameter used for generating a sequence for DM-RS based on a quasi-orthogonal sequence, which is a pseudo-random sequence, The maximum total number of layers and the maximum number of layers per UE can be determined.
As an example, assume that MU-MIMO is implemented in one resource block in which a normal cyclic prefix (CP) as shown in FIG. 5 is used. If the number of resource elements to which the DM-RS is mapped is 12, the number of orthogonal sequences is 2, and the number of SCID is 2, the total number of maximum layers is two orthogonal sequences (OCC1 (or antenna port 7) OCC2 (or antenna port 7)) and two SCID values (0 and 1). Therefore, in the case of MU-MIMO, the maximum number of layers is four, and the maximum number of layers per terminal is two.
As another example, suppose that the normal C as shown in FIG. 6 is implemented in SU-MIMO in one resource block. If the number of resource elements to which DM-RS is mapped is 24, the number of orthogonal sequences is 4, and the SCID value is 1, the total number of maximum layers is four (4) orthogonal sequences for resource element A (OCC1 (OCC 3 (antenna port 9), OCC 4 (antenna port 7), OCC 2 (antenna port 8), OCC 5 (antenna port 11), OCC 7 (antenna port 13) Port 10), OCC6 (antenna port 12), OCC8 (antenna port 13)). Therefore, up to 8 maximum number of layers per UE are supported for SU-MIMO.
Hereinafter, the layer number of the DM-RS is denoted as
≪
(1-1) SU-MIMO (less than 2 layers) or MU-MIMO (less than 2 layers per terminal)
Table 1 shows a case where one layer is allocated to each terminal, and Table 2 shows a case where two layers are allocated per terminal. The situation where two or more layers are allocated per terminal may occur when a codeword is retransmitted or a plurality of codewords are transmitted. Up to two codewords per terminal can be transmitted (
Referring to Tables 1 and 2, combinations of four types of antenna ports and SCIDs are defined as (7,0), (7,1), (8,0), (8,1) When a layer is assigned, one of four types is assigned. When two layers are allocated per terminal, combinations of two antenna ports and SCIDs having the same SCID among combinations of four types of antenna ports and SCIDs are combined.
(1-2) SU-MIMO (more than 3 layers)
Tables 3 to 8 show cases where three to eight layers are allocated per terminal.
(7,0), (8,0), (9,0), (10,0), (11,0), (12,0), (13,0) , (14, 0). Thus, combinations of eight types of antenna ports and SCIDs are defined. The eight types are sequentially selected and allocated as many as the number of layers allocated to the UE. For example, a maximum of four layers per codeword is allocated.
(1-3) Retransmission
Tables 9 to 12 show a case where one codeword among the two codewords is retransmitted and a maximum of four layers are allocated per terminal.
Referring to Tables 9 to 12, in Table 9, there are two types of combinations of the antenna port and the SCID. However, since this is the same as the case where one layer is allocated per UE in SU-MIMO or MU-MIMO, it does not need to be indicated separately in a transparent environment.
The number of possible cases for each situation (SU-MIMO / MU-MIMO, retransmission, etc.) with respect to combinations of possible antenna ports and SCIDs in FIGS. 5 and 6 are shown in Tables 1 to 12. The number of cases where only one codeword (codeword 0) is transmitted and the case where two codewords (
1) One codeword (codeword 0): 4 types (Table 1) +3 types (Tables 10 to 12) = 7 types
2) For two codewords (
A table indicating the number of combinations of the antenna port and the SCID according to the number of possible layers given to the UE when the codeword is one or two can be configured as shown in the following table.
Referring to Table 13, the BS can indicate the antenna port, the scrambling ID, and the number of layers by 3 bits (having values of 0 to 7) in the case of one codeword or two codewords to the UE, Information is called an antenna port, a scrambling identifier, and a layer number indication information (having
Referring to FIGS. 5 and 6 and Tables 1 to 13, it is assumed that the maximum number of layers of the MU-MIMO is four and the maximum number of layers per terminal is two. The identifier and the number indication of the layer are posted. However, as described above, the multi-dimensional MIMO system can support additional spatial freedom and higher-order MU-MIMO. Thus, in another aspect of the disclosure, an embodiment is disclosed that extends the number of layers for a DM-RS. For example, the total maximum number of layers of MU-MIMO may be 8, and the maximum number of layers per terminal may be 2 or 4. The structure for supporting this is shown in FIGS. 7 and 8. FIG. 7 is an example in which the DM-RS according to yet another embodiment is mapped to 12 resource elements, 4 antenna ports, and 4 orthogonal sequence lengths, and FIG. 8 illustrates a DM- , Four antenna ports, and orthogonal sequence length = 2.
≪ Example 2-1 >
First, referring to FIG. 7, if the maximum number of layers per terminal is two , combinations of possible antenna ports and SCIDs are represented by (p, y) as follows.
(2-1-1) SU-MIMO (less than 2 layers) or MU-MIMO (less than 2 layers per terminal)
Table 14 shows a case where one layer is allocated per terminal, and Table 15 shows a case where two layers are allocated per terminal. The situation where two or more layers are allocated per terminal may occur when a codeword is retransmitted or a plurality of codewords are transmitted. Up to two codewords per terminal can be transmitted (
(11,0), (11,13), (13,0), (7,0), (7,1), (8,0) , (13, 1) Thus, combinations of eight types of antenna ports and SCID are defined. If one layer is allocated to each terminal, one of eight types is allocated. When two layers are allocated per terminal, combinations of two antenna ports and SCIDs having the same SCID among combinations of 8 types of antenna ports and SCIDs can be bundled.
(2-1-2) SU-MIMO (more than 3 layers)
Tables 16 to 21 show cases where three to eight layers are allocated per terminal. This is the case where the combination of the antenna port and the SCID used in (1-2) in the first embodiment, that is, SU-MIMO (three or more layers) is used without modification.
(11, 0), (12, 0), (13, 0), (8, 0) , (14,0). Eight kinds of layers are defined, and the eight types are sequentially selected and allocated as many as the number of layers allocated to the terminal. For example, a maximum of four layers per codeword is allocated.
(2-1-3) Retransmission
Tables 22 to 25 show a case where one codeword among the two codewords is retransmitted and a maximum of four layers are allocated per terminal.
Referring to Tables 22 to 25, in Table 22, there are six kinds of combinations of the antenna port and the SCID in total, but this is the same as the case where one layer is allocated per UE in SU-MIMO or MU-MIMO in Table 14 It does not need to be indicated separately in a transparent environment.
Table 7 shows the number of combinations of possible antenna ports and SCIDs for each situation (SU-MIMO / MU-MIMO, retransmission, etc.) when the maximum number of layers per UE is 2 in FIG. The number of combinations of possible antenna ports and SCIDs divided by the case where only one codeword (codeword 0) is transmitted and the case where two codewords (
1) For one codeword (codeword 0): 8 (Table 14) +3 (Table 23 to Table 25) = 11
2) For two codewords (
Up to 18 bits may be required up to 5 bits in order to represent the combination of the antenna port and the SCID according to the number of layers. In this case, the 3-bit information shown in Table 13 is insufficient, Two bits may be required.
As an example of a method for minimizing the addition of the number of bits, in the embodiment 2-1, some of the combinations of the antenna port and the SCID in the first embodiment are used without modification. For example,
As another example of the method for minimizing the addition of the number of bits, in the embodiment 2-1, only the case of which the most use frequency is high and which is essential among the 12 cases in Table 15 is referred to as an actual antenna port, a scrambling identifier, As the number designation information of the display device. Here, only the optimal cases for maximizing compatibility and balance with the first embodiment in which the total maximum number of layers of MU-MIMO is four and the maximum number of layers per terminal is two can be selectively used. For example, only
By combining the measures for minimizing the addition of the number of bits in this way, i) all of the possible cases in the 2-1 embodiment are not included in the cases of the first embodiment, ii) Since only cases are represented by the antenna port, the scrambling identifier, and the number indication information of the layer, the antenna port, the scrambling identifier, and the number indication information of the layer can be identified by adding only one bit.
According to this concept, one table may be additionally provided in addition to Table 13, which is used for indicating the antenna port, the scrambling identifier and the number of layers, as shown in the following table. This is to support SU-MIMO (less than two layers) and MU-MIMO.
Referring to Table 26, it is assumed that i) is not included in the case of the first embodiment, and ii) shows some cases to be actually used. An antenna port corresponding to one codeword, a scrambling identifier, The number indication information values 0 to 3 of Table 2 correspond to
Meanwhile, the base station can individually inform the mobile station which one of the antenna ports, the scrambling identifier, and the table used for indicating the number of layers in Table 13 and Table 26 is to be used. For this purpose, the base station transmits signaling or RRC control signaling may be used.
For example, the antenna port, the scrambling identifier, and the layer number indication information in the DCI transmitted from the base station to the mobile station are configured with 4 bits, one of which indicates which table in Table 13 and Table 26 is used, Indicates the actual antenna port, the scrambling identifier, and the number indication information of the layer in the table used to indicate the antenna port, the scrambling identifier, and the number of layers. Alternatively, selection information for the 1-bit table may be included in the DCI in addition to the 3-bit antenna port, the scrambling identifier, and the number indication information of the layer.
As another example, a 1-bit RRC signaling may be transmitted from the base station to the mobile station, in which the antenna port, the scrambling identifier, and the number indication information of the layer are composed of 3 bits, indicating which table in Table 13 or Table 26 is to be used. In this case, the additional 1 bit is referred to as selection information for a table used for indicating an antenna port, a scrambling identifier, and the number of layers.
On the other hand, the embodiments of the DM-RS precoding scheme of the base station in the embodiment 2-1 may differ according to 1-bit additional instruction information.
The precoding scheme of the base station can be determined according to the following rule, depending on which one of the bits individually informs the UE whether to use the antenna port, the scrambling identifier, and the table used for indicating the number of layers have. For example, if the 1 bit is 0, the table for indicating the antenna port, the scrambling identifier, and the number of layers based on Table 13 is 1, the table for indicating the antenna port, the scrambling identifier, Suppose you are instructed to use.
a) If the 1-bit value is 0
When a DM-RS is transmitted on one antenna port, one layer is mapped to either antenna port p = 7 or antenna port p = 8.
- When a DM-RS is transmitted over two or more antenna ports, layers with
b) if the 1-bit value is 1,
When a DM-RS is transmitted on one antenna port, one layer is mapped to either antenna port p = 11 or antenna port p = 13.
- When DM-RS is transmitted on two antenna ports, layers with
Let MU-MIMO based on Table 13 be called A scheme and MU-MIMO based on Table 26 be B scheme. A scheme is a scheme for implementing MU-MIMO for up to four layers (maximum of 2 per mobile station) with
The base station can dynamically allocate either the A scheme or the B scheme to a plurality of MU-MIMOs, and the UE can dynamically allocate the A scheme and the B scheme to the MU-MIMO scheme according to the example in which the antenna port, the scrambling identifier, Method, it is possible to implement MU-MIMO without limitation for a maximum of 8 layers (maximum 2 for each terminal).
On the other hand, according to the example of transmitting 1-bit RRC signaling, each terminal belongs to A group using A scheme and B group using B scheme. In order to perform MU-MIMO for a maximum of 8 layers (maximum 2 for each terminal), a terminal belonging to A group and a terminal belonging to A group can not be assigned dynamically to a plurality of MU-MIMOs by RRC signaling. A restriction that MU-MIMO should be performed between terminals belonging to group B can be followed. However, there is an advantage of not imposing additional overhead on the DCI. In other words, there is no limitation in MU-MIMO having maximum total number of layers of 4, and limitation of dynamic scheduling is possible only in MU-MIMO having maximum total number of layers of 5 or more.
Referring again to Table 26, there are many reserved values in Table 26, which may waste unnecessary resources. In fact, it does not include more than three layers of SU-MIMO. Therefore, a second embodiment is disclosed as a method for utilizing the reserved value for the instruction of SU-MIMO.
≪ Example 2-2 &
(2-2-2) SU-MIMO (three or more layers) are separately used in addition to (2-1-2) in the second embodiment, In addition to (2-1-3) of the embodiment, the following (2-2-3) retransmissions are also used, and the remainder is the same as in the (2-1) embodiment.
(2-2-2) SU-MIMO (more than 3 layers)
ii) (14, 0), (7, 0), (8, 0)
ii) (14,0), (7,0), (8,0), (9,0)
ii) (7,0), (8,0), (9,0), (10,0)
(2-2-3) Retransmission
An example of a table used to indicate the number of additional configurable antenna ports, scrambling identifiers, and layers when using cases such as (2-2-2) and (2-2-3) is shown in Table 37 . Unlike Table 26, it supports SU-MIMO (up to 8 layers) and MU-MIMO.
Referring to Table 37, the antenna port, the scrambling identifier, and the number indication information values (values) 0 to 3 of one codeword correspond to
The relationship between the table used for indicating the antenna port, the scrambling identifier and the number of layers in Table 37, the antenna port in Table 13, the scrambling identifier, and the table used for indicating the number of layers will be described. The antenna ports {7, 8, 9, 10, 11, 12, 13, 14} in the table used to indicate the number of ports, scrambling identifiers and layers indicate the antenna port, scrambling identifier, Corresponds to the antenna ports {11, 13, 12, 14, 7, 9, 8, 10} in the table used for indicating. That is, when eight antenna ports are divided into a first antenna port group {7, 8, 9, 10} and a second antenna port group {11, 12, 13, 14}, in the first embodiment, The first antenna port group is first mapped to the first antenna port group sequentially from the first layer to the last layer and then mapped to the second antenna port group. In the second embodiment, the second antenna port group is mapped to {11, 13, 12 , 14}, and in the
Table 38 shows another example of a table used to indicate the number of additional configurable antenna ports, scrambling identifiers, and layers when using cases such as (2-2-2) and (2-2-3). Unlike Table 26, it supports SU-MIMO (up to 8 layers) and MU-MIMO.
Referring to Table 38, an antenna port, a scrambling identifier, and number indication information values (values) 0 to 3 of one codeword correspond to
The relationship between the table used for indicating the antenna port, the scrambling identifier, and the number of layers in Table 38, the antenna port in Table 13, the scrambling identifier, and the table used for indicating the number of layers will be described. The antenna ports {7, 8, 9, 10, 11, 12, 13, 14} in the table used to indicate the number of ports, scrambling identifiers and layers indicate the antenna port, scrambling identifier, Corresponds to antenna ports {11, 13, 12, 14, 7, 8, 9, 10} in the table used for indicating. That is, when eight antenna ports are divided into a first antenna port group {7, 8, 9, 10} and a second antenna port group {11, 12, 13, 14}, in the first embodiment, The first antenna port group is first mapped to the first antenna port group sequentially from the first layer to the last layer and then mapped to the second antenna port group. In the second embodiment, the second antenna port group is mapped to {11, 13, 12 , 14}. In the group, 12 and 13 are mapped in reverse order), and then mapped to the first antenna port group (the order is {7, 8, 9, 10}. That is, reverse mapping is performed between the layer and the antenna port.
Meanwhile, the base station can individually inform the mobile station which one of the antenna ports, the scrambling identifier, and the table used for indicating the number of layers in Table 13 and Table 37 (or Table 38) is to be used. For this, Or RRC signaling may be used. Embodiments of concrete signaling in the second to eighth embodiments can be equally applied to the signaling scheme in the above-mentioned < 2-1 >
In addition, the embodiment of the DM-RS precoding scheme of the base station in the embodiment 2-2 may differ according to 1-bit additional instruction information as in the above-described precoding scheme.
The precoding scheme of the base station can be determined according to the following rule, depending on which one of the bits individually informs the UE whether to use the antenna port, the scrambling identifier, and the table used for indicating the number of layers have. For example, if the 1 bit is 0, the table for indicating the antenna port, the scrambling identifier, and the number of layers based on Table 13 is 1, indicating the antenna port, the scrambling identifier, and the number of layers based on Table 37 or Table 38 Let us assume that a table is used.
a) If the 1-bit value is 0
When a DM-RS is transmitted on one antenna port, one layer is mapped to either antenna port p = 7 or antenna port p = 8.
- When a DM-RS is transmitted over two or more antenna ports, layers with
b) if the 1-bit value is 1,
When a DM-RS is transmitted on one antenna port, one layer is mapped to either antenna port p = 11 or antenna port p = 13.
- When a DM-RS is transmitted over two or more antenna ports, layers with
≪ Example 2-3 >
The 2-3 embodiment is an embodiment specifically specifying the addition of the changes to the method of indicating each table and the OCC length (legnth) applied in the example of the 2-2 embodiment.
First, whether to use Table 39 below, or whether to use one of Table 40 to Table 43 below, is indicated by upper level signaling such as RRC and is included in DCI indicating antenna port, scrambling identifier and number of layers Which is a 3-bit field, is to be selected. The upper level signaling of the RRC or the like may be signaling whether to use the existing DM-RS configuration described in Table 13 of the
In Table 39, an OCC having a length of 2 is applied in the case of an antenna port corresponding to one codeword, a scrambling identifier, and a number indication information value (value) 0 to 3 of a layer. Also, when the number corresponds to an antenna port corresponding to two codewords, a scrambling identifier, and a number indication value (value) 0 ~ 1 of a layer, an OCC having a length of 2 is also applied. In the remaining cases, an OCC of
In Table 40, the antenna port, the scrambling identifier, and the number of layers indicated by the number indicator information value of each antenna port, the scrambling identifier, and the layer are the same as those in Table 39. [ However, in Table 40, the OCC with a length of 4 applies in all cases. That is, in the case of an antenna port corresponding to one codeword, a scrambling identifier, and the number indication information values (values) 0 to 3 of the layer, an OCC having a length of 2 is applied as shown in Table 39 But OCC with
The same applies to Tables 41 to 43, which will be described later, in all cases in which the OCC having a length of 4 is applied.
Tables 41 to 43 show the case where the
If it is indicated that the DM-RS configuration for FM-MIMO is configured with higher-level signaling such as RRC as described above, one of Tables 40 to 43 above for directing the DM-RS configuration for FD-MIMO will be used, If it is indicated that it is not configured, Table 39 above will be used to indicate the existing DM-RS configuration described in Table 13 of Example 1.
At this time, if it is indicated that the DM-RS configuration for FM-MIMO is configured by upper level signaling such as the RRC, one of Tables 40 to 43 for directing the DM-RS configuration for FD-MIMO will be applied, The table 40 to 43 is as follows.
As shown below, a 1-bit indication value is added. If the bit value of 1 bit is 0, Table 40 is applied. If the bit value of 1 bit is 1, Table 41 (or Table 42 or Table 43) do. Conversely, Table 40 is applied if the bit value of 1 bit is 1, and Table 41 (or Table 42 or Table 43) is applied when the bit value of 1 bit is 0.
In this case, the 1-bit indication value indicates the value of the "antenna port (s), scrambling identity and number of layers field indicator" or "antenna port, scrambling A value of a table indication field for identifier and number of layers (antenna port (s), scrambling identity and number of layers) or a value of a layer to antenna port mapping indication field a value of an indicator or a field which may be referred to as various terms such as a value of a " precoding indication field "
That is, the term for the indicator or the field is not limited to the above example, and may be variously defined in the line indicating the present invention. In the present invention, however, the antenna port, the scrambling identifier, layer to antenna port mapping indication field because the table for the antenna port (s), scrambling identity and number of layers is associated with the layer to antenna port mapping in the layer. .
1) One bit indicating the application of either Table 40 or Table 41
1-a) When the value of the " layer to antenna port mapping indication field "is A (A = 0 or A = 1)
When a DM-RS is transmitted on one antenna port, the
When a DM-RS is transmitted over two or more antenna ports, layers with
- Table 40 applies to tables for antenna port, scrambling identifier and number of layers.
1-b) When the value of the " layer to antenna port mapping indication field "is 1-A (A = 0 or A = 1)
When a DM-RS is transmitted on one antenna port, the
When a DM-RS is transmitted on two antenna ports,
- When a DM-RS is transmitted over three or more antenna ports, layers with
- Table 41 applies to tables for antenna port, scrambling identifier and number of layers.
2) One bit indicating the application of either Table 40 or Table 42
2-a) When the value of the " layer to antenna port mapping indication field "is A (A = 0 or A = 1)
When a DM-RS is transmitted on one antenna port, the
When a DM-RS is transmitted over two or more antenna ports, layers with
- Table 40 applies to tables for antenna port, scrambling identifier and number of layers.
2-b) When the value of the " layer to antenna port mapping indication field "is 1-A (A = 0 or A = 1)
When a DM-RS is transmitted on one antenna port, the
- When a DM-RS is transmitted over two or more antenna ports, layers with
- Table 42 applies to tables for antenna port, scrambling identifier and number of layers.
3) One bit indicating the application of either Table 40 or Table 43
3-a) When the value of the " layer to antenna port mapping indication field "is A (A = 0 or A = 1)
When a DM-RS is transmitted on one antenna port, the
When a DM-RS is transmitted over two or more antenna ports, layers with
- Table 40 applies to tables for antenna port, scrambling identifier and number of layers.
3-b) When the value of the " layer to antenna port mapping indication field "is 1-A (A = 0 or A = 1)
When a DM-RS is transmitted on one antenna port, the
- When a DM-RS is transmitted over two or more antenna ports, layers with
- Table 43 applies to tables for antenna port, scrambling identifier and number of layers.
The signaling for indicating whether the value of the " layer to antenna port mapping indication field "is 0 or 1 may be used for upper level signaling such as RRC, a field can be constructed. Alternatively, it may be indicated using a field present in the existing DCI to enable some degree of dynamic signaling while reducing signaling overhead. For example, the "layer to antenna port mapping indication field" is added to the PDSCH RE mapping and quasi-co-allocation indicator (PQI), which is a parameter set for indicating PDSCH RE mapping and quasi- And then add the parameters for that.
Meanwhile, the OCC applied to each antenna port is shown in Table 44 below. Here, the application of the
≪ Third Embodiment >
Referring to FIG. 7, when the maximum number of layers per UE is four , combinations of possible antenna ports and SCIDs are represented by (p, y) 4.
(3-1) SU-MIMO (less than 4 layers) or MU-MIMO (less than 4 layers per terminal)
Tables 45 to 48 show cases where one to four layers are allocated to each terminal.
(3-2) SU-MIMO (more than 3 layers)
Tables 49 to 54 show cases where three to eight layers are allocated per terminal. This is the case where the combination of the antenna port and SCID used in (1-2) in the first embodiment, that is, SU-MIMO (three or more layers) is used without modification.
(3-3) Retransmission
Tables 55 to 58 show a case where one codeword of two codewords is retransmitted and a maximum of four layers are allocated per terminal.
Referring to Tables 55 to 58, in Table 55, there are six layers in total, but this is the same as when SU-MIMO or MU-MIMO in Table 45 allocates one layer per UE. Therefore, in a transparent environment, It does not need to be.
In Table 7, the number of combinations of possible antenna ports and SCIDs for each situation (SU-MIMO / MU-MIMO, retransmission, etc.) is shown in Tables 45 to 58 when the maximum number of layers per UE is four. The number of combinations of possible antenna ports and SCIDs divided by the case where only one codeword (codeword 0) is transmitted and the case where two codewords (
1) For one codeword (codeword 0): 8 types (Table 45) + 4 types (Tables 56 to 58) = 12 types
2) For two codewords (
Up to 28 bits may be required up to 5 bits to represent the antenna port, the scrambling identifier, and the layer number indication information. In this case, the 3-bit antenna port, the scrambling identifier, , And additional 1 to 2 bits may be required.
As an example of a method for minimizing the addition of the number of bits, in the third embodiment, some of the combinations of the antenna port and the SCID in the first embodiment are used without modification. For example, the
As another example of the method for minimizing the addition of the number of bits, in the third embodiment, only the case of which the most use frequency is high among the 12 cases in Table 46 and which is essential is referred to as the actual antenna port, the scrambling identifier, Used as instruction information. Here, only the optimal cases for maximizing compatibility and balance with the first embodiment in which the total maximum number of layers of MU-MIMO is four and the maximum number of layers per terminal is two can be selectively used. For example, only
By combining measures to minimize the addition of the number of bits in this way, i) of all possible cases in the third embodiment are not included in the cases of the first embodiment, and ii) , The scrambling identifier, and the number indication information of the layer, it is possible to identify the antenna port, the scrambling identifier, and the number indication information of the layer only by adding one bit.
According to this concept, one table may be additionally provided in addition to Table 13, which is used for indicating the antenna port, the scrambling identifier and the number of layers, as shown in the following table. This is to support SU-MIMO (less than 4 layers) and MU-MIMO.
Referring to Table 59, it shows some cases that are actually used, ii) not included in the cases of the first embodiment. For example, an antenna port corresponding to one codeword, a scrambling identifier, and number indication information values 0 to 3 of layers correspond to
Meanwhile, the base station can individually inform which of the antenna ports, the scrambling identifiers, and the tables used to indicate the number of layers in Table 13 and Table 59, and to which the signaling or RRC signaling of the physical layer is to be used . Embodiments of specific signaling in the third embodiment can be equally applied to the signaling scheme in the above-mentioned < 2-1 embodiment >.
In addition, embodiments of the DM-RS precoding scheme of the base station in the third embodiment may differ according to 1-bit additional instruction information as in the above-described precoding scheme.
The precoding scheme of the base station can be determined according to the following rule, depending on which one of the bits individually informs the UE whether to use the antenna port, the scrambling identifier, and the table used for indicating the number of layers have. For example, if 1 bit is 0, a table for indicating an antenna port, a scrambling identifier, and the number of layers based on Table 13 is 1, a table for indicating an antenna port, a scrambling identifier, Suppose you are instructed to use.
a) If the 1-bit value is 0
When a DM-RS is transmitted on one antenna port, one layer is mapped to either antenna port p = 7 or antenna port p = 8.
- When a DM-RS is transmitted over two or more antenna ports, layers with
b) if the 1-bit value is 1,
When a DM-RS is transmitted on one antenna port, one layer is mapped to either antenna port p = 11 or antenna port p = 13.
- When DM-RS is transmitted on two antenna ports, layers with
- When a DM-RS is transmitted over three or four antenna ports, layers with
8 is an example in which a DM-RS according to another embodiment is mapped to 24 resource elements and 4 antenna ports.
≪ Example 4-1 >
Referring to FIG. 8, when the maximum number of layers per UE is two , combinations of possible antenna ports and SCIDs are represented by (p, y) as follows.
(4-1-1) SU-MIMO (less than 2 layers) or MU-MIMO (less than 2 layers per terminal)
Table 60 shows a case where one layer is allocated per UE, and Table 61 shows a case where two layers are allocated per UE. The situation where two or more layers are allocated per terminal may occur when a codeword is retransmitted or a plurality of codewords are transmitted. Up to two codewords per terminal can be transmitted (
(7,0), (7,1), (8,0), (8,1), (9,0), (9,1), (10,0) , (10, 1), and combinations of eight types of antenna ports and SCIDs are defined. When one layer is allocated to each terminal, a combination of any one of eight antenna ports and SCID is allocated. When two layers are allocated per terminal, combinations of two antenna ports and SCIDs having the same SCID among combinations of 8 types of antenna ports and SCIDs can be bundled.
(4-1-2) SU-MIMO (more than 3 layers)
Tables 62 to 67 show cases where three to eight layers are allocated per terminal. This is the case where the combination of the antenna port and the SCID used in (1-2) in the first embodiment, that is, SU-MIMO (three or more layers) is used without modification.
(7,0), (8,0), (9,0), (10,0), (11,0), (12,0), (13,0) , (14, 0). Thus, combinations of eight types of antenna ports and SCIDs are defined. The eight types are sequentially selected and allocated as many as the number of layers allocated to the UE. For example, a maximum of four layers per codeword is allocated.
(4-1-3) Retransmission
Tables 68 to 72 show a case where one codeword of two codewords is retransmitted and a maximum of four layers are allocated per terminal.
Referring to Tables 68 to 71, in Table 68, there are six types of combinations of the antenna port and the SCID in total, but this is the same as the case where one layer is allocated per UE in SU-MIMO or MU-MIMO in Table 60 It does not need to be indicated separately in a transparent environment.
In Table 8, the number of combinations of possible antenna ports and SCIDs for each situation (SU-MIMO / MU-MIMO, retransmission, etc.) is shown in Table 60 to Table 71 when the maximum number of layers per UE is two. Now, the number of possible layers divided into the case where only one codeword (codeword 0) is transmitted and the case where two codewords (
1) For one codeword (codeword 0): 8 types (Table 60) +3 types (Table 69 to Table 71) = 11 types
2) For two codewords (
Up to 5 bits may be required to represent the maximum number of 18 cases as the antenna port, the scrambling identifier, and the number indication information of the layer. In this case, the 3-bit antenna port, the scrambling identifier, , And additional 1 to 2 bits may be required.
As an example of a method for minimizing the addition of the number of bits, in the 4-1 embodiment, some of the combinations of the antenna port and the SCID in the first embodiment are used without modification. For example,
As another example of a method for minimizing the addition of the number of bits, in the 4-1 embodiment, only the case of which the most use frequency is high among the 12 cases in Table 61 and which is essential is referred to as an actual antenna port, a scrambling identifier, As the number designation information of the display device. Here, only the optimal cases for maximizing compatibility and balance with the first embodiment in which the total maximum number of layers of MU-MIMO is four and the maximum number of layers per terminal is two can be selectively used. For example, only
Combining the measures for minimizing the addition of the number of bits in this manner, i) is not included in the cases of the first embodiment among all possible cases in the 4-1 embodiment, ii) Since only cases are represented by the antenna port, the scrambling identifier, and the number indication information of the layer, the antenna port, the scrambling identifier, and the number indication information of the layer can be identified by adding only one bit.
According to this concept, one table may be additionally provided in addition to Table 13, which is used for indicating the antenna port, the scrambling identifier and the number of layers, as shown in the following table. This is to support SU-MIMO (less than two layers) and MU-MIMO.
Referring to Table 72, i) an antenna port corresponding to one codeword, a scrambling identifier, and a layer corresponding to one codeword are shown, which are not included in the cases of the first embodiment, and ii) The number indication information values 0 to 3 of Table 5 correspond to
Meanwhile, the base station can individually inform the mobile station which one of the antenna ports, the scrambling identifier, and the table used for indicating the number of layers in Table 13 and Table 72 is to be used. For this, the signaling or RRC signaling of the physical layer is used . Embodiments of concrete signaling in the 4-1 embodiment may be applied to the same signaling scheme in the above-mentioned < 2-1 embodiment >.
In addition, embodiments of the DM-RS precoding scheme of the base station in the 4-1 embodiment may differ depending on 1-bit additional instruction information as in the precoding scheme described above.
The precoding scheme of the base station can be determined according to the following rule, depending on which one of the bits individually informs the UE whether to use the antenna port, the scrambling identifier, and the table used for indicating the number of layers have. For example, if the 1 bit is 0, a table for indicating an antenna port, a scrambling identifier, and the number of layers based on Table 13 is 1, a table for indicating an antenna port, a scrambling identifier, Suppose you are instructed to use.
a) If the 1-bit value is 0
When a DM-RS is transmitted on one antenna port, one layer is mapped to either antenna port p = 7 or antenna port p = 8.
- When a DM-RS is transmitted over two or more antenna ports, layers with
b) if the 1-bit value is 1,
When a DM-RS is transmitted on one antenna port, one layer is mapped to either antenna port p = 9 or antenna port p = 10.
When a DM-RS is transmitted over two antenna ports, layers with
Referring again to Table 72, there are many reserved values in Table 72, which may waste unnecessary resources. In fact, it does not include more than three layers of SU-MIMO. Therefore, a fourth embodiment is disclosed as a method for utilizing the reserved value for the instruction of SU-MIMO.
≪ Example 4-2 &
(4-2-2) SU-MIMO (three or more layers) are separately used in addition to (4-1-2) of the fourth embodiment, and the fourth to In addition to (4-1-3) of the embodiment, the following (4-2-3) retransmission is used separately, and the remainder is the same as in the (4-1) embodiment.
(4-2-2) SU-MIMO (more than 3 layers)
ii) (7,0), (8,0), (11,0)
ii) (8,0), (11,0), (12,0)
(ii) (8,0), (11,0), (12,0), (13,0)
ii) (11,0), (12,0), (13,0), (14,0)
(4-2-3) Retransmission
An example of a table used to indicate the number of additional configurable antenna ports, scrambling identifiers, and layers when using cases such as (4-2-2) and (4-2-3) is shown in Table 83 . Unlike Table 72, it supports SU-MIMO (up to 8 layers) and MU-MIMO.
Referring to Table 83, an antenna port, a scrambling identifier, and number indication information values (values) 0 to 3 of one codeword correspond to
That is, when eight antenna ports are divided into a first antenna port group {7, 8, 9, 10} and a second antenna port group {11, 12, 13, 14}, in the first embodiment, The first antenna port group is first mapped to the first antenna port group sequentially from the first layer to the last layer and then mapped to the second antenna port group. In the fourth to ninth embodiments, the first antenna port group is sequentially mapped to {9, 10 (12, 11, 14, 13) in the group after being mapped to the first antenna port group (7, 8, 9, 10 in the group and 7, , 12 are mapped first in reverse order, 13 and 14 are mapped later in reverse order). That is, the mapping order is switched between the layer and the antenna port.
Another example of a table used to indicate the number of additional configurable antenna ports, scrambling identifiers, and layers when using cases such as (4-2-2) and (4-2-3) . Unlike Table 72, it supports SU-MIMO (up to 8 layers) and MU-MIMO.
Referring to Table 84, the antenna port, the scrambling identifier and the number indication information values (values) 0 to 3 of one codeword correspond to
That is, when eight antenna ports are divided into a first antenna port group {7, 8, 9, 10} and a second antenna port group {11, 12, 13, 14}, in the first embodiment, The first antenna port group is first mapped to the first antenna port group sequentially from the first layer to the last layer and then mapped to the second antenna port group. In the fourth to ninth embodiments, the first antenna port group is sequentially mapped to {9, 10 (11, 12, 13, 14) in the group after mapping first to 9, 10 in the group, 7, 8 in the group) Mapped). That is, the mapping order is switched between the layer and the antenna port.
On the other hand, the base station can individually inform the mobile station which one of the antenna ports, the scrambling identifier, and the table used to indicate the number of layers in Table 13 and Table 83 (or Table 84) is to be used. For this, Or RRC signaling may be used. Embodiments of concrete signaling in the 4-1 embodiment may be applied to the same signaling scheme in the above-mentioned < 2-1 embodiment >.
In addition, embodiments of the DM-RS precoding scheme of the base station in the 4-1 embodiment may differ depending on 1-bit additional instruction information as in the precoding scheme described above.
The precoding scheme of the base station can be determined according to the following rule, depending on which one of the bits individually informs the UE whether to use the antenna port, the scrambling identifier, and the table used for indicating the number of layers have. For example, if the 1 bit is 0, the table for indicating the antenna port, the scrambling identifier, and the number of layers based on Table 13 is 1, indicating the antenna port, the scrambling identifier, and the number of layers based on Table 83 or Table 84 Let us assume that a table is used.
a) If the 1-bit value is 0
When a DM-RS is transmitted on one antenna port, one layer is mapped to either antenna port p = 7 or antenna port p = 8.
- When a DM-RS is transmitted over two or more antenna ports, layers with
b) if the 1-bit value is 1,
When a DM-RS is transmitted on one antenna port, one layer is mapped to either antenna port p = 9 or antenna port p = 10.
When a DM-RS is transmitted over two or more antenna ports, layers with
<Fifth Embodiment>
Referring to FIG. 8, when the maximum number of layers per UE is four , combinations of possible antenna ports and SCIDs are represented by (p, y) as follows.
(5-1) SU-MIMO (less than 4 layers) or MU-MIMO (less than 4 layers per terminal)
Tables 85 to 88 show cases where one to four layers are allocated to each terminal.
(5-2) SU-MIMO (more than 3 layers)
Tables 89 to 94 show cases where three to eight layers are allocated per terminal. This is the case where the combination of the antenna port and the SCID used in (1-2) in the first embodiment, that is, SU-MIMO (three or more layers) is used without modification.
(5-3) Retransmission
Tables 95 to 98 show cases in which one codeword among two codewords is retransmitted, and a maximum of four layers are allocated per terminal.
Referring to Tables 95 to 98, in Table 95, there are six kinds of combinations of antenna port and SCID in total, but this is the same as when SU-MIMO or MU-MIMO in Table 79 allocates one layer per UE It does not need to be indicated separately in a transparent environment.
Table 8 shows the number of possible antenna port and SCID combinations for each situation (SU-MIMO / MU-MIMO, retransmission, etc.) when the maximum number of layers per UE is four in FIG. Now, the number of possible layers divided into the case where only one codeword (codeword 0) is transmitted and the case where two codewords (
1) For one codeword (codeword 0): 8 types (Table 85) + 4 types (Table 96 to Table 98) = 12 types
2) For two codewords (
Up to 28 bits may be required up to 5 bits to represent the antenna port, the scrambling identifier, and the layer number indication information. In this case, the 3-bit antenna port, the scrambling identifier, , And additional 1 to 2 bits may be required.
As one example of a method for minimizing the addition of the number of bits, in the fifth embodiment, some of the combinations of the antenna port and the SCID in the first embodiment are used without modification. For example, the
As another example of the method for minimizing the addition of the number of bits, in the fifth embodiment, only the case where the most use frequency is high among the 12 cases shown in Table 86 and only a part of the essential case is the actual antenna port, the scrambling identifier, Used as instruction information. Here, only the optimal cases for maximizing compatibility and balance with the first embodiment in which the total maximum number of layers of MU-MIMO is four and the maximum number of layers per terminal is two can be selectively used. For example, only
By combining the measures for minimizing the addition of the number of bits, it is possible to combine all of the possible cases in the fifth embodiment, i) without being included in the cases of the first embodiment, ii) cases may be represented by the antenna port, the scrambling identifier, and the number indication information of the layer. Therefore, the antenna port, the scrambling identifier, and the number indication information of the layer can be identified only by adding one bit.
According to this concept, one table may be additionally provided in addition to Table 13, which is used for indicating the antenna port, the scrambling identifier and the number of layers, as shown in the following table. This is to support SU-MIMO (less than 4 layers) and MU-MIMO.
Referring to Table 99, i) some cases to be actually used, but not included in the cases of the first embodiment. For example, an antenna port corresponding to one codeword, a scrambling identifier, and number indication information values 0 to 3 of layers correspond to
Meanwhile, the base station can individually inform the mobile station which one of the antenna ports, the scrambling identifier, and the table used for indicating the number of layers in Table 13 and Table 99 is to be used. For this, the signaling or RRC signaling of the physical layer is used . Embodiments of specific signaling in the fifth embodiment can be equally applied to the signaling scheme in the above-mentioned < 2-1 embodiment >.
In addition, embodiments of the DM-RS precoding scheme of the base station in the fifth embodiment may be different according to 1-bit additional instruction information as in the above-described precoding scheme.
The precoding scheme of the base station can be determined according to the following rule, depending on which one of the bits individually informs the UE whether to use the antenna port, the scrambling identifier, and the table used for indicating the number of layers have. For example, if the 1 bit is 0, a table for indicating an antenna port, a scrambling identifier, and a number of layers based on Table 13 is 1, a table for indicating an antenna port, a scrambling identifier, Suppose you are instructed to use.
a) If the 1-bit value is 0
When a DM-RS is transmitted on one antenna port, one layer is mapped to either antenna port p = 7 or antenna port p = 8.
- When a DM-RS is transmitted over two or more antenna ports, layers with
b) if the 1-bit value is 1,
When a DM-RS is transmitted on one antenna port, one layer is mapped to either antenna port p = 9 or antenna port p = 10.
- When DM-RS is transmitted on two antenna ports, layers with
When a DM-RS is transmitted over three or four antenna ports, layers with
Hereinafter, the description will be made on the basis of the description of the first embodiment, the second embodiment, the second embodiment, the third embodiment, the fourth embodiment, and the fourth embodiment. A method of performing communication between a base station and a mobile station using a method according to the fifth and the fifth embodiments will be described in detail.
9 is a flowchart illustrating a DM-RS transmission / reception method between a terminal and a base station according to an exemplary embodiment of the present invention.
Referring to FIG. 9, the base station generates a reference signal sequence r (m) to be used in a resource configuration for DM-RS (S900). For example, r (m) may be calculated by the pseudo-random sequence c (i) based on a gold sequence as follows:
Here, m = 0,1, ..., 12N RB max , DL -1 (in the case of a general CP) or m = 0,1, ..., 16N RB max , DL -1. N RB max , DL represents the maximum number of RBs in the downlink.
When there are a plurality of layers (SU-MIMO or MU-MIMO), the base station generates c1 (i) using the first SCID (0 or 1) for the first terminal or the zeroth codeword, (M) using the second SCID (0 or 1) for the second terminal or the first codeword, and generates the reference signal sequence r2 (m) corresponding thereto Can be generated.
The base station multiplies the reference signal sequence r (m) by an orthogonal sequence (OCC) defined for each specific antenna port to generate a modulation symbol a (p) k, l of the demodulation value (S905).
When there are a plurality of layers (SU-MIMO or MU-MIMO), the base station multiplies the reference signal sequence r1 (m) by OCC1 along the first antenna port with respect to the first terminal or the zeroth codeword to generate a first modulation symbol And generate a second modulation symbol by multiplying the reference signal sequence r2 (m) by OCC2 along the second antenna port with respect to the second terminal or the first codeword.
The base station maps the modulation symbol a (p) k, l of the demodulation value to a resource element RE defined by a subcarrier of an index k in each PRB and an OFDM symbol of an index l (S910).
The base station may map the modulation symbols a (p) k, l of the demodulation values to the resource elements according to the DM-RS patterns of Figs. 5-8. If there are multiple layers (SU-MIMO or MU-MIMO), the base station may map both the first modulation symbol and the second modulation symbol to the same resource element.
In step S915, the BS transmits the DM-RS mapped to the resource element to the UE, and includes the antenna port, the scrambling identifier, and the layer number indication information of the DM-RS in the DCI and transmits the information to the UE through the PDCCH. At this time, selection information for a table used to indicate the number of 1-bit antenna ports, scrambling identifiers, and layers may be transmitted from the BS to the MS according to the embodiment.
As an example, selection information for a table used to indicate a 1-bit antenna port, a scrambling identifier, and the number of layers may be included in the RRC signaling and transmitted.
As another example, selection information for a table used to indicate a 1-bit antenna port, a scrambling identifier, and the number of layers may be included in the DCI and transmitted. In this case, the DCI includes 4-bit antenna port, scrambling identifier and layer number indication information, or 1-bit antenna port, scrambling identifier and selection information for a table used to indicate the number of layers, A scrambling identifier, and a number indication of the layer.
From a layer viewpoint, the first layer is formed by a combination of a first SCID and a first antenna port, and the second layer is formed by a combination of a second SCID and a second antenna port. Therefore, the base station can determine the length of the orthogonal sequence according to the length of the orthogonal sequence according to the first embodiment, the second embodiment, the second embodiment, the second embodiment, the third embodiment, Based on the table used to indicate the antenna port, the scrambling identifier, and the number of layers according to the 4-1th embodiment, the 4-2th embodiment, and the 5th embodiment, The antenna port, the scrambling identifier, and the number indication information of the layer.
As an example, if the length of the orthogonal sequence is 4, the base station may be configured to perform the steps of the first embodiment, the second embodiment, the second embodiment, the second embodiment, A scrambling identifier and a layer number indication information mapped to a combination of the antenna port and the SCID in a table used for indicating an antenna port, a scrambling identifier, and a number of layers according to an embodiment of the present invention, .
As another example, when the length of the orthogonal sequence is 2, the base station may transmit the antenna port according to the first embodiment, the fourth embodiment, the fourth embodiment, and the fifth embodiment, Scrambling ID and layer number indication information mapped to the combination of the antenna port and the SCID in a table used for indicating the scrambling identifier and the number of layers.
The terminal receiving the DM-RS and the DCI receives the DM-RS and the DCI based on the 1-bit antenna port, scrambling identifier, selection information for the table used to indicate the number of layers, and antenna port, scrambling identifier, RS. For example, the terminal selects a table to be used for indicating an antenna port, a scrambling identifier, and a number of layers based on selection information for a table used for indicating an antenna port, a scrambling identifier, and a number of layers. The terminal finds the antenna port (or orthogonal sequence) and the SCID used for the transmission of the DM-RS based on the selected table and antenna port, the scrambling identifier, and the number indication information of the layer. The terminal demaps the received DM-RS based on the found antenna port and the SCID from the resource element to extract the modulation symbol of the demodulation value, and multiplies the received modulation symbol by the orthogonal sequence to extract the estimated reference signal sequence r '(m) (S920). The terminal generates a reference signal sequence r (m) in the same manner as the base station (S925), and performs channel estimation by comparing r (m) with r (m) (S930).
10 is a block diagram illustrating a wireless communication system including a terminal and a base station according to an embodiment of the present invention.
10, a terminal 1000 includes an RF unit (radio frequency unit) 1010, a
The
The
The
The
The
The
The base station processor 1080 may include a
The reference signal generator 1090 generates a reference signal sequence r (m) to be used in the resource configuration for the DM-RS. For example, r (m) may be generated as shown in equation (2) by a pseudo-random sequence c (i) based on a gold sequence. When there are a plurality of layers (SU-MIMO or MU-MIMO), the reference signal generator 1090 generates c1 (i) using the first SCID (0 or 1) for the first terminal or the zeroth codeword (M) by using the second SCID (0 or 1) for the second terminal or the first codeword, and generates the reference signal sequence r1 The sequence r2 (m) can be generated.
The reference signal generator 1090 multiplies the reference signal sequence r (m) by an orthogonal sequence (OCC) defined for each specific antenna port to generate a modulation symbol a (p) k, l of a demodulation value. For example, when there are a plurality of layers (SU-MIMO or MU-MIMO), the reference signal generator 1090 generates OCC1 according to the first antenna port with respect to the first terminal or the zeroth codeword, ) To generate a first modulation symbol, and multiply the reference signal sequence r2 (m) by OCC2 along the second antenna port with respect to the second terminal or the first codeword to generate a second modulation symbol.
The
The
From a layer viewpoint, the first layer is formed by a combination of a first SCID and a first antenna port, and the second layer is formed by a combination of a second SCID and a second antenna port. Therefore, the
As an example, when the length of the orthogonal sequence is 4, the base station processor 1080 may be configured to perform the processing of the first embodiment, the second embodiment, the second embodiment, A scrambling identifier, and a layer number indication information in a table used to indicate the antenna port, the scrambling identifier, and the number of layers according to the third embodiment, (1000).
As another example, when the length of the orthogonal sequence is 2, the base station processor 1080 may determine whether the length of the orthogonal sequence is " 1 ", " Scrambling identifier and layer number indication information in a table used to indicate the antenna port, the scrambling identifier, and the number of layers, and transmits the number to the terminal 1000 through the
Claims (5)
Generating a reference signal sequence to be used in a resource configuration for the DM-RS;
Generating a modulation symbol of a demodulation value by multiplying an orthogonal sequence defined for each antenna port by the reference signal sequence;
Mapping the modulation symbol to a resource element;
Transmitting the DM-RS to a terminal;
Transmitting to the terminal selection information for a table used for indicating an antenna port, a scrambling identifier, and a number of layers; And
And transmitting indication information indicating an antenna port, a scrambling identifier, and a number of layers to the terminal,
When performing communication based on a multiuser multi-user multiple input multiple output (MIMO) supporting only two layers per terminal, the table maps an antenna port having an antenna port number of 9 or more to each layer The transmission method of the DM-RS.
And the selection information is included in the downlink control information as one bit and is transmitted.
Wherein the selection information is included in a radio resource control (RRC) message as 1 bit.
Wherein the selection information indicates any one of two tables.
In the precoding for the DM-RS, the layers having layer numbers 0, 1, 2, 3, 4, 5, 6 and 7 are assigned to antenna port numbers 11, 13, 12, 14, 7, 9, Mapped to the DM-RS.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
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| KR1020150051111 | 2015-04-10 | ||
| KR20150051111 | 2015-04-10 |
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| KR20160121367A true KR20160121367A (en) | 2016-10-19 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10757666B2 (en) | 2017-02-06 | 2020-08-25 | Lg Electronics Inc. | Method and device for transmitting and receiving signal between user equipment and base station in wireless communication system |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10757666B2 (en) | 2017-02-06 | 2020-08-25 | Lg Electronics Inc. | Method and device for transmitting and receiving signal between user equipment and base station in wireless communication system |
| US11483783B2 (en) | 2017-02-06 | 2022-10-25 | Lg Electronics Inc. | Method and device for transmitting and receiving signal between user equipment and base station in wireless communication system |
| US11902921B2 (en) | 2017-02-06 | 2024-02-13 | Lg Electronics Inc. | Method and device for transmitting and receiving signal between user equipment and base station in wireless communication system |
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