WO2013024985A2

WO2013024985A2 - Transmission point, method for configuring reference signal for same, terminal, and method for transmitting reference signal for same

Info

Publication number: WO2013024985A2
Application number: PCT/KR2012/006080
Authority: WO
Inventors: 윤성준; 홍성권; 박경민
Original assignee: 주식회사 팬택
Priority date: 2011-08-12
Filing date: 2012-07-31
Publication date: 2013-02-21
Also published as: KR20130018075A; WO2013024985A3

Abstract

The present invention relates to a wireless communication system in which a terminal transmits an uplink reference signal.

Description

Transmitter, reference signal setting method of the transmitter, terminal, reference signal transmission method of the terminal

In order to demodulate an uplink signal or estimate an uplink channel state in a wireless communication system, the terminal may transmit an uplink reference signal. A reference signal (eg, a DeModulation Reference Signal (DM-RS)) used for demodulating an uplink signal may be a data channel (eg, a physical uplink shared channel (PUSCH)) or a control channel (eg, a PUCCH). (Physical Uplink Control Channel) and is mainly transmitted for channel measurement for demodulation.

In a wireless communication system, orthogonality may be deteriorated when uplink reference signals transmitted by a terminal in a specific cell and uplink reference signals transmitted by a terminal located at a cell boundary of an adjacent cell are allocated different sequences in the same bandwidth. In particular, when considering uplink CoMP (Coordinated Multi-Point transmission and reception), orthogonality deterioration problem needs to be considered more seriously.

An object of the present invention is to provide an apparatus and method for improving orthogonality when transmitting an uplink reference signal to a terminal located at a cell boundary or a terminal operating in uplink CoMP.

According to an embodiment of the present invention, region setting information on an area for allocating an uplink reference signal through some subcarriers having a predetermined interval among subcarriers is transmitted through a radio resource control (RRC) or a physical broadcasting channel (PBCH). A reference signal information transmitter to transmit; And a resource allocation information transmitter for transmitting resource allocation information for a resource region through which a specific terminal transmits an uplink signal.

Another embodiment of the present invention, through the RRC (Radio Resource Control) or PBCH (Physical Broadcasting Channel) for the region setting information for the region for allocating the uplink reference signal through some subcarriers having a constant interval of the subcarriers Transmitting reference signal information; And a resource allocation information transmission step of transmitting resource allocation information for a resource region through which a specific terminal transmits an uplink signal.

According to another embodiment of the present invention, when a resource region for transmitting an uplink signal is included in an area for allocating an uplink reference signal through some subcarriers having a predetermined interval among subcarriers, the uplink reference signal may be part of the uplink reference signal. A reference signal mapping unit for allocating subcarriers; And a reference signal transmitter for transmitting the uplink reference signal, wherein the information on the region for allocating an uplink reference signal through some subcarriers having a predetermined interval among the subcarriers is RRC (Radio Resource Control) or PBCH. It provides a terminal characterized in that received through (Physical Broadcasting Channel).

According to another embodiment of the present invention, a sequence of uplink reference signals through some subcarriers having a constant interval among subcarriers in a resource region according to the following equation:

A reference signal mapping unit for assigning; And a reference signal transmitter for transmitting the uplink reference signal.

In the above equation,

Is the base sequence,

Is the number of subcarriers through which the uplink reference signal is transmitted,

Is a parameter passed through RRC,

Is a parameter passed through DCI,

Is a parameter determined according to the cell ID and the slot number,

Is an orthogonal sequence,

Indicates the layer index.

According to another embodiment of the present invention, when a resource region for transmitting an uplink signal is included in an area for allocating an uplink reference signal through some subcarriers having a predetermined interval among subcarriers, the uplink reference signal may be part of the uplink reference signal. A reference signal mapping step of allocating subcarriers; And transmitting a reference signal for transmitting the uplink reference signal, wherein the information on the region for allocating an uplink reference signal through some subcarriers having a predetermined interval among the subcarriers is RRC (Radio Resource Control) or The present invention provides a method for transmitting a reference signal of a terminal, which is received through a physical broadcasting channel (PBCH).

Assigning a reference signal mapping step; And a reference signal transmission step of transmitting the uplink reference signal.

In the above equation,

Is the base sequence,

Is a parameter passed through RRC,

Is a parameter passed through DCI,

Is a parameter determined according to the cell ID and the slot number,

Is an orthogonal sequence,

Indicates the layer index.

According to the present invention described above, orthogonality may be improved when transmitting an uplink reference signal.

1 illustrates a communication system to which embodiments of the present invention are applied.

2 illustrates an example of a method of transmitting a PUSCH, a DM-RS, and an SRS in an uplink of a wireless mobile communication.

FIG. 3 is an enlarged diagram of a DM-RS for a terminal illustrated in resource block units in FIG. 2 and illustrated in subcarrier units.

4 illustrates an example in which a terminal is located at a boundary between cells having different cell IDs.

FIG. 5 illustrates a case where a terminal operating in cooperative multi-point transmission and reception between cells exists as another example.

FIG. 6 illustrates a case in which a UE operating in CoMP is present in a system in which a narrow cell by a narrow band transmitter is located in a wide cell by a wide band transmitter.

7 illustrates a case in which a DM-RS of at least some terminals is not allocated to all subcarriers, and a subcarrier to which a DM-RS of one terminal is allocated does not coincide with a subcarrier to which a DM-RS of another terminal is allocated. Illustrated.

8 is a block diagram of a wireless communication system according to an embodiment.

Hereinafter, some embodiments of the present invention will be described in detail with reference to the accompanying drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible even though they are shown in different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

Communication systems are widely deployed to provide various communication services such as voice, packet data, and the like.

Referring to FIG. 1, a communication system includes a user equipment (UE) 10 and a transmission terminal 20 (Transmission Point, TP) that performs uplink and downlink communication with the terminal 10.

In the present specification, the terminal 10 or a user equipment (UE) is a comprehensive concept that means a user terminal in wireless communication. In addition to the UE in WCDMA, LTE, and HSPA, as well as a mobile station (MS) and a UT (GSM) in GSM, It should be interpreted as a concept that includes a user terminal, a subscriber station (SS), and a wireless device.

The transmitting terminal 20 or cell generally refers to a station communicating with the terminal 10, and includes a base station, a Node-B, an evolved Node-B, and a base transceiver. It may be called other terms such as a System, an Access Point, a Relay Node, and the like.

In the present specification, the transmission terminal 20 or a cell should be interpreted in a comprehensive sense indicating a part of a region covered by a base station controller (BSC) in a CDMA, a NodeB of a WCDMA, etc., and a radio remote connected to a base station. Comprehensive means any type of device that can communicate with a single terminal, such as a head, relay node, a sector of a macro cell, a site, or a micro cell such as a femtocell or picocell. Used as a concept.

In the present specification, the terminal 10 and the transmitting terminal 20 are used as a transmitting and receiving entity used in implementing the technology or the technical idea described in this specification in a comprehensive sense and are not limited to the terms or words specifically referred to.

Although one terminal 10 and one transmission terminal 20 are shown in FIG. 1, the present invention is not limited thereto. It is possible for one transmission terminal 20 to communicate with the plurality of terminals 10, and one terminal 10 may communicate with the plurality of transmission terminals 20.

There are no limitations to the multiple access scheme applied to a communication system, and the present invention provides the code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), and OFDM. Applicable to various multiple access schemes such as FDMA, OFDM-TDMA, and OFDM-CDMA.

In addition, the present invention is a combination of the TDD (Time Division Duplex) method is transmitted using a different time, uplink transmission and downlink transmission, FDD (Frequency Division Duplex) method is transmitted using a different frequency, combining the TDD and FDD Applicable to hybrid duplexing method.

Specifically, embodiments of the present invention are applicable to asynchronous wireless communication that evolves into Long Term Evolution (LTE) and LTE-advanced through GSM, WCDMA, HSPA, and synchronous wireless communication that evolves into CDMA, CDMA-2000, and UMB. Can be. The present invention should not be construed as being limited or limited to a specific wireless communication field, but should be interpreted as including all technical fields to which the spirit of the present invention can be applied.

Referring to FIG. 1, the terminal 10 and the transmitter 20 may communicate in uplink and downlink wirelessly.

In wireless communication, one radio frame (radioframe) consists of 10 subframes, and one subframe consists of two slots. The radio frame has a length of 10 ms and the subframe has a length of 1.0 ms. In general, the basic unit of data transmission is a subframe unit, and downlink or uplink scheduling is performed on a subframe basis.

One slot includes seven symbols (in the case of a normal cyclic prefix) or six symbols (in the case of an extended cyclic prefix) in the time domain. In this case, the time-frequency domain defined by 12 subcarriers corresponding to 180 kHz in the frequency domain with one slot in the time domain may be referred to as a resource block (RB), but is not limited thereto.

The transmitting end 20 may perform downlink transmission to the terminal 10. The transmitter 20 may transmit a physical downlink shared channel (PDSCH) as a downlink data channel for unicast transmission. In addition, the transmitter 20 may schedule downlink control information such as scheduling required for reception of the PDSCH and transmission for uplink data channel (for example, a physical uplink shared channel (PUSCH)). Indicator for distinguishing a physical downlink control channel (PDCCH) as a downlink control channel used for transmitting downlink control information (DCI) including grant information, a region of a PDSCH and a PDCCH Physical Control Format Indicator Channel (PCFICH) for transmitting the PHY, Physical HARQ Indicator Channel (PHICH) for transmitting the HARQ (Hybrid Automatic Repeat request) for uplink transmission The control channel can be transmitted. Hereinafter, the transmission and reception of signals through each channel will be described in the form of transmission and reception of the corresponding channel.

The terminal 10 may perform uplink transmission to the transmitting end 20. The terminal 10 may transmit a PUSCH as an uplink data channel. In addition, the terminal 10 requests resource allocation when transmitting data in HARQ acknowledgment (NACK) / negative ACK (NACK), channel status report, and uplink indicating whether the downlink transport block has been successfully received. A physical uplink control channel (PUCCH) as an uplink control channel used for transmitting uplink control information (UCI) including a scheduling request may be transmitted.

The base station 20 includes a cell-specific reference signal (CRS), a MBSFN reference signal (Multicast / Broadcast over Single Frequency Network Reference Signal, MBSFN-RS), and a UE-specific reference signal (UE-) in downlink. Specific Reference Signal (DM-RS), Positioning Reference Signal (PRS), and CSI Reference Signal (Channel Status Information Reference Signal, CSI-RS) may be transmitted.

The terminal 10 may transmit a demodulation reference signal (DM-RS) and a sounding reference signal (SRS) in uplink.

2 illustrates an example of a method of transmitting a PUSCH, a DM-RS, and an SRS in an uplink of a wireless mobile communication. In FIG. 2, the horizontal axis represents a symbol on the time axis and represents one subframe as a whole. The vertical axis represents a resource block (RB) on the frequency axis.

Referring to FIG. 2, each UE UE1 to UE3 may transmit the

PUSCHs

201, 203, and 205 through a resource block indicated by the DCI for each UE UE1 to UE3. The DM-

RSs

202, 204, and 206, which are reference signals used to demodulate the

PUSCHs

201, 203, and 205 transmitted by the UEs UE1 to UE3, are

PUSCHs

201, 203, and 205 on the frequency axis. In a resource block, such as, the time axis may be transmitted in one symbol of each of two slots in a subframe. The SRS 207 transmitted by the terminals may be transmitted in the last symbol of the subframe.

DM-RS (202, 204, 206) is associated with

PUSCH

201, 203, 205 transmission or PUCCH transmission (DM-RS associated with PUSCH transmission is shown in Figure 2), channel measurement for demodulation (channel It is mainly transmitted for estimation. At this time, the DM-

RSs

202, 204, and 206 are transmitted for every slot in every subframe in which the

PUSCHs

201, 203, and 205 are transmitted. In addition, since information on the transmission bandwidth (BW) of DM-

RSs

202, 204, and 206 expressed in resource block units is associated with

PUSCH

201, 203, and 205 transmission or PUCCH transmission, a signal previously transmitted is transmitted. Based on the information. For example, in the case of the DM-

RSs

202, 204, and 206 associated with the

PUSCHs

201, 203, and 205, the DM-

RSs

202 and 204 are assigned to resource blocks to which the

PUSCHs

201, 203, and 205 are allocated. 206 is transmitted, the resource block allocation information of the DM-RS is based on the resource block allocation information of the PUSCH. In this case, the resource blocks to which the

PUSCHs

201, 203, and 205 are allocated for each UE UE1 to UE3 are based on a field value for resource block allocation of downlink control information (DCI).

FIG. 3 is an enlarged view of a DM-RS 202 for a UE UE1 shown in FIG. 2 on a subcarrier basis. As an example, in FIG. 2, the DM-RS 202 for the UE UE1 is transmitted through four resource blocks, and the four resource blocks total 48 (= 4 * 12) 12 subcarriers for each block. Subcarriers r (0) to r (47).

The current DM-RS sequence is mapped and transmitted for all subcarriers in the resource block used for DM-RS transmission. In this case, the DM-RS sequence may be generated by cyclically delaying a base sequence based on the Zadoff-Chu sequence as shown in Equation 1 below. Can be.

[Equation 1]

Basic sequence in equation (1)

Is based on the Zadoff-Chu sequnece, a kind of Constant Amplitude Zero Auto-Correlation (CAZAC) sequence, and u and which of the Zadoff-Chu sequences of the same length are used. It is determined by v, and the values of u and v are determined by cell ID, slot number, and hopping. Basic sequence

Is a length corresponding to the length of the resource block used for DM-RS transmission.

= Number of RBs used x number of subcarriers in the RB (usually 12). Each sequence value in the sequence corresponds to each subcarrier in the resource region allocated for DM-RS transmission and is 0 to

With an index of -1 and a circular delay value (

Cyclic delay.

In Equation 1, the cyclic delay value (

Is used to calculate

Has three parameters (

,

) Is calculated as the remainder of the sum divided by 12.

May be delivered to the terminal through higher layer signaling such as RRC.

May be transmitted to the terminal through the DCI.

May be specified and determined according to a cell ID and a slot number.

Basic sequence

Multiplied by

To generate a circular delay. For example,

= 1,

= 2π / 12, and the DM-RS is transmitted in one resource block (12 subcarriers) (n is 0 to 11).

Is 0, 2π / 12, 4π / 12, 6π / 12, 8π / 12, 10π / 12, 12π / 12, 14π / 12, 16π / 12, 18π / 12, 20π / 12, 22π / 12 Will have In such a case

Are located at equidistant intervals of 2π / 12 (30 °) in the complex plane.

In Equation 1

Represents an Orthogonal Code Cover (OCC).

May be [1 1] or [1 -1]. Above

And

May be determined by 3 bits in DCI for each layer as shown in Table 1 below. Also in Equation 1 and Table 1

Means the layer index.

TABLE 1

DM-RS sequence in the manner described above

Can be obtained.

Corresponding to the cyclic delay value of the DM-RS sequence defined in Equation 1

In this case, the orthogonality is maintained by satisfying the following equation (2).

[Equation 2]

In Equation 2, Z is an integer.

On the other hand, when transmitting a DM-RS from a terminal located at a plurality of cell boundaries having different cell IDs, this DM-RS may cause interference with the DM-RS transmitted from another terminal.

Referring to FIG. 4, the terminal 411 uses the transmitting terminal 421 having B as the cell ID as a serving cell, and the terminal 412 serves the transmitting terminal 422 having A as the cell ID. It is a cell. When the terminal 411 transmits the DM-RS in the DM-RS sequence calculated using the cell ID B, since the terminal 411 is located at the boundary between cells, the DM-RS transmitted by the terminal 411 is transmitted. Not only stage 421 but also transmission stage 422 may be reached. When the location of all or part of the resources of the DM-RS transmitted by the terminal 411 and the physical resources of the DM-RS transmitted by the terminal 412 overlap, the DM-RS transmitted by the terminal 411 is determined by the terminal ( 412 may act as interference to the DM-RS transmitted. In order to reduce interference by the DM-RS transmitted by the terminal 411, the orthogonality of the DM-RS transmitted by the terminal 411 and the DM-RS transmitted by the terminal 412 should be guaranteed.

FIG. 5 illustrates a case in which a terminal operating in coordinated multi-point transmission and reception (CoMP) exists between cells as another example.

Referring to FIG. 5, the terminal 511 illustrates a terminal operating in uplink CoMP, and the terminal 512 illustrates a terminal not operating in uplink CoMP. The DM-RS transmitted by the CoMP terminal 511 is received by the transmitting end 521 and the transmitting end 522. The sequence of DM-RSs transmitted by the terminal 511 is calculated using the cell ID B. The DM-RS transmitted by the terminal 512 that does not operate with CoMP is received by the transmitting terminal 522. The sequence of DM-RSs transmitted by the terminal 512 is calculated using the cell ID A. In this case, the transmitting end 522 should receive both the DM-RS transmitted by the terminal 511 operating in CoMP and the DM-RS transmitted by the terminal 512 not operating in CoMP. When the resources of the DM-RS transmitted by the terminal 511 operating in CoMP and the DM-RS transmitted by the terminal 512 not operating in CoMP overlap, the orthogonality of the DM-RS must be guaranteed in order to distinguish and receive them. do.

FIG. 6 illustrates a case in which a UE operating in CoMP is present in a system in which a narrow cell by the narrow bandwidth transmitter 622 is located in the wide cell by the broadband transmitter 621.

In FIG. 6, the transmit end 621 may be a wide area base station, and the transmit end 622 may be a narrow band transmit end such as an RRH, a relay node, a femtocell, or a picocell.

Referring to FIG. 6, the terminal 611 illustrates a terminal operating in uplink CoMP, and the terminal 612 illustrates a terminal not operating in uplink CoMP. The DM-RS transmitted by the terminal 611 operating in CoMP is received by the wide area transmitter 621 and the narrow channel 622. The sequence of DM-RSs transmitted by the terminal 611 is calculated using the cell ID B. The DM-RS transmitted by the terminal 612 which does not operate with CoMP is received by the wide area transmission terminal 621. The sequence of DM-RSs transmitted by the terminal 612 is calculated using the cell ID A. In this case, the wide area transmitter 621 must receive both the DM-RS transmitted by the terminal 611 operating in CoMP and the DM-RS transmitted by the terminal 612 not operating in CoMP. If the resources of the DM-RS transmitted by the UE 611 operating in CoMP and the DM-RS transmitted by the terminal 612 not operating in CoMP overlap, the orthogonality of the DM-RS must be ensured in order to distinguish and receive them. do.

In order to ensure orthogonality between DM-RSs transmitted by different terminals, the following method may be possible.

First, the use of the cyclic delay CS in Equation 1 may be considered. In order for DM-RSs transmitted by a plurality of UEs to be orthogonal through a cyclic delay, u and v must be the same in Equation (1). Since u and v shown in Equation 1 are calculated based on the cell IDs, a separate additional algorithm must be prepared in which the cell IDs of the plurality of cells are the same or even if the cell IDs are different. In addition, in order for a plurality of DM-RSs to be orthogonal through a cyclic delay, the number of resource blocks to which the DM-RS is transmitted and the point at which the resource blocks start are the same, so that a plurality of transmitting DM-RSs are allocated only within the same resource block To overlap one another. In this case, two DM-RSs have the same basic sequence and different cyclic delay values, and the two DM-RSs are distinguished through cyclic delay values. This method requires additional algorithms or signaling to equalize the u and v values of the DM-RS sequence, and causes severe scheduling restrictions to equalize the allocation bandwidth and allocation start point of the two sequences. .

As another method, using the OCC in Equation 1 may be considered. DM-RSs transmitted by a plurality of terminals may use different OCCs ([1 1] and [1 -1]). This method has no problem of matching u and v, and scheduling limitation. However, since OCC is possible only in two cases of [1 1] and [1 -1], orthogonality can be guaranteed only for up to two terminals, and in case of overlapping DM-RSs transmitted from three or more terminals, It cannot provide orthogonality.

As another method, it may be considered to set a different subcarrier to which the DM-RS is allocated for each terminal. 7 illustrates a case in which a DM-RS of at least some terminals is not allocated to all subcarriers, and a subcarrier to which a DM-RS of one terminal is allocated does not coincide with a subcarrier to which a DM-RS of another terminal is allocated. Illustrated.

In the example shown in Figs. 2 and 3, the DM-RS is allocated and mapped to all subcarriers of the resource block to which the PUSCH is assigned. In this case, when resource blocks of the DM-RSs transmitted by the plurality of terminals overlap, the DM-RSs are allocated and mapped to the same subcarrier.

4 to 6, the serving cell of the UE UE1 is located in another cell having a different cell ID from the serving cells of the other UEs UE2 ˜ UE5. At this time, the UE UE1 belongs to a different cell from other UEs UE2 to UE5, but the UE-UE is located at a cell boundary or the UE-UE1 performs a CoMP operation so that the DM-RS from the UE-UE1 can be used. Is also received in the serving cells of the other terminals UE2 to UE5.

In this case, the resource block 701 to which the DM-RS transmitted by the UE UE1 is allocated overlaps with the resource blocks 702 and 703 to which the DM-RS transmitted by the UEs UE2 and UE3 are allocated. And the resource blocks 704 and 705 to which the DM-RS transmitted by the UE5 is allocated do not overlap. In the case of the DM-RS resource blocks 704 and 705 that do not overlap the resource block 701 to which the DM-RS transmitted by the UE UE1 is allocated, the DM-RS sequence is applied to all subcarriers 709 and 710 in the resource block. Is assigned, and Equation 1 described above may be applied.

Meanwhile, in the case of the DM-RS resource block 701 transmitted by the UE UE1 and the DM-RS resource blocks 702 and 703 overlapping all or part thereof, the DM-RS sequence is assigned to only some subcarriers in the resource block. Can be.

Referring to FIG. 7, a DM-RS sequence is allocated to a subcarrier 706 in which the subcarrier index divided by 2 is 1 (odd) for the UE UE1, and the UEs UE2 and UE3 are allocated to the UEs UE2 and UE3. A DM-RS sequence may be allocated to

subcarriers

707 and 708 where the carrier index divided by 2 is 0 (even). In this case, the DM-RS transmitted from the UE UE1 and the DM-RS transmitted from the UEs UE2 and UE3 share all or part of the same resource block but are allocated to different subcarriers, so that they do not interfere with each other. Can be. This method has an advantage of maintaining orthogonality even when the DM-RS basic sequence is different or the bands allocated to the DM-RS are different between terminals. This method can be applied to the case of FIGS. 4 to 6.

In the example of FIG. 7, the subcarriers are allocated according to the remainder of dividing the subcarrier index by 2. However, when the DM-RSs transmitted from N (N≥2) terminals are allocated to the same resource block, each terminal is allocated to the same resource block. The subcarrier can be allocated according to the remainder obtained by dividing the subcarrier index by N. In this case, the subcarriers to which the DM-RS is allocated for each terminal have a constant interval (N subcarrier intervals).

On the other hand, when the terminal allocating the DM-RS sequence to all subcarriers and the terminal allocating the DM-RS sequence to some subcarriers having a constant interval in the above-described IFDMA scheme share the same bandwidth (or some bandwidth), orthogonality This may not be maintained. Therefore, in the example of FIG. 7,

terminals

701, 702, and 703 that allocate a DM-RS sequence to some subcarriers having a predetermined interval and

terminals

704 and 705 that allocate a DM-RS sequence to all subcarriers. It is necessary to distinguish.

Referring to FIG. 8, the wireless communication system includes a transmitter 810 and a terminal 820. The transmitter 810 may include a reference signal information transmitter 812 and a resource allocation information transmitter 814. The terminal 820 may include a reference signal mapping unit 822 and a reference signal transmitter 824.

The reference signal information transmitter 812 may transmit information on a resource block for allocating a DM-RS sequence to some subcarriers through an upper layer signaling such as RRC in the IFDMA scheme. Alternatively, the reference signal information transmitter 812 may transmit this information through a physical broadcasting channel (PBCH) transmitted to all terminals in the cell.

An area capable of operating with IFDMA is represented in units of resource blocks (RBs) or resource block groups (RBGs) and may be configured in the following manner.

In one example, the index of the starting resource block (or starting resource block group) of the region capable of operating with IFDMA and the number of resource blocks (or resource blocks) of the contiguous region starting from the starting resource block (or starting resource block group). Number of groups) can be indicated with information expressed together.

In this case, the total number of bits may be as shown in Equation 3 below.

[Equation 3]

In equation (3)

Is the total number of resource blocks for uplink. In equation (3)

Instead, the total number of resource block groups for uplink may be substituted. When the number of resource blocks constituting one resource block group is P,

Instead of

Can be substituted.

In another example, the contiguous resource block region may be represented by a total of two regions in units of resource blocks or resource block groups, and may be indicated as regions capable of operating with IFDMA.

The total number of bits in the resource block group unit may be as shown in Equation 4 below.

[Equation 4]

In equation (4)

Is the total number of resource blocks for uplink,

Is the number of resource block groups. In the case of resource block units, P = 1 may be substituted in Equation 4.

In another example, a bitmap of a resource block unit or a resource block group unit may be expressed to indicate an area capable of operating with IFDMA.

In the resource block group unit, the total number of bits may be as shown in Equation 5 below.

[Equation 5]

In addition, an area capable of operating with IFDMA in various ways may be expressed in units of resource blocks or resource block groups.

The information on the region operating in the IFDMA transmitted from the reference signal information transmitter 812 of the transmitter 810 may be received and stored by the terminal 820.

In addition, N, which is the number of DM-RSs that can overlap the resource block, and M, which is a number indicating whether the DM-RS of a specific terminal (or a terminal belonging to a specific cell) is assigned to any remaining value when the subcarrier index is divided by N ( Information about 0≤M≤N-1 may be transmitted from the transmitting terminal 810 to the terminal 820. Alternatively, these values may be predefined values shared by the transmitting terminal 810 and the terminal 820. For example, N may be defined in advance by sharing the transmission terminal 810 and the terminal 820, M (0≤M≤N-1) is transmitted through high layer signaling such as RRC It may be transmitted from the terminal 810 to the terminal 820. Alternatively, both N and M may be transmitted from the transmitting end 810 to the terminal 820 through high layer signaling such as RRC.

The resource allocation information transmitter 814 of the transmitter 810 may transmit resource allocation information for uplink data transmission, that is, information on a resource block to which a PUSCH of the corresponding terminal 820 is allocated, to the terminal 820. . This resource allocation information is based on the value of the resource block allocation field of the DCI.

The reference signal mapping unit 822 of the terminal 820 may determine how to transmit the DM-RS based on the information on the region operating in the IFDMA and the resource allocation information. When the PUSCH transmission resource block allocated by the resource allocation information is not included in the region operating with IFDMA, as shown in FIGS. 2 and 3, the sequence of the DM-RS associated with the PUSCH is a resource block to which the PUSCH is allocated. May be allocated to all subcarriers of.

Meanwhile, when the PUSCH transmission resource block allocated by the resource allocation information is included in an area operating with IFDMA, as shown in FIG. 7, the sequence of the DM-RS associated with the PUSCH is constant in the resource block to which the PUSCH is allocated. It may be allocated to some subcarriers with an interval.

Alternatively, when a part of the PUSCH transmission resource block allocated by the resource allocation information is located in an area operating with IFDMA, as shown in FIG. 7, the sequence of the DM-RS associated with the PUSCH is a resource block to which the PUSCH is allocated. May be allocated to some subcarriers with a constant spacing.

The reference signal transmitter 824 of the terminal 820 transmits the DM-RS mapped by the reference signal mapper 822.

As another example, whether the reference signal information transmitter 812 of the transmitting end 810 allocates a DM-RS sequence to each terminal 820 through some subcarriers having a predetermined interval in a resource block in an IFDMA manner, or A signal (for example, a 1-bit signal) indicating whether to allocate a DM-RS sequence can be transmitted through all subcarriers. The indication signal may be signaled semi-statically through higher layer signaling such as RRC, or may be dynamically included in DCI or the like for uplink grant.

In other words, when allocating resource blocks used for PUSCH to each terminal (through a field for resource block allocation of DCI for uplink grant), the transmitting end 810 is allocated to all subcarriers through scheduling for each terminal. A terminal allocating a DM-RS sequence and a terminal allocating a DM-RS sequence to some subcarriers having a predetermined interval are distinguished. The reference signal information transmitter 812 of the transmitter 810 transmits the segment information (for example, the aforementioned 1-bit signal) to the terminal 820.

Also, the transmitter 810 transmits resource allocation information of the PUSCH through a field for resource block allocation of DCI for uplink grant. When the above-described division information is signaled through RRC, the division information may be transmitted first and the resource allocation information may be transmitted later. When the above-described division information is signaled through the DCI, the division information and the resource allocation information may be transmitted at the same time.

The reference signal mapping unit 822 of the terminal 820 may map the DM-RS sequence based on information on whether the terminal 820 transmits the DM-RS in the IFDMA scheme. Allocate a DM-RS sequence to all subcarriers of the resource block allocated with the resource allocation information when it is indicated as not the IFDMA scheme, and have a certain interval in the resource block allocated with the resource allocation information when indicated as the IFDMA scheme. Assign a DM-RS sequence to the subcarrier.

In addition to the above-described region for mapping the DM-RS sequence to the IFDMA scheme or signaling for indicating whether to operate in the IFDMA scheme, to which subcarrier to map the DM-RS sequence to the IFDMA scheme (ie, subcarrier) Signaling of what is the remainder of the index divided by N to map to that subcarrier, e.g. to map to odd or even subcarriers when N = 2, may be transmitted from the transmitter to the UE. have. This may be indicated by higher layer signaling such as RRC. Alternatively, this information may be predefined on the system. For example, a DM-RS sequence may be mapped to an even subcarrier when the cell ID is even, and an odd subcarrier when the cell ID is odd.

On the other hand, when the DM-RS sequence is allocated by the above-described IFDMA method, the length of the sequence allocated to the same bandwidth (resource block) can be reduced to 1 / N. For example, in the case of N = 2, since the DM-RS sequence is not allocated to all subcarriers but to even or odd subcarriers, the length of the sequence is reduced by half.

If the length of the sequence is reduced by half,

May not be located at equal intervals in the complex plane. For example, when a specific terminal is allocated to one resource block, the DM-RS sequence is allocated only to six subcarriers (n = 0 to 5) out of a total of 12 subcarriers when the IFDMA scheme is applied.

= 1,

When = 2π / 12,

Have values of 0, 2π / 12, 4π / 12, 6π / 12, 8π / 12, and 10π / 12, respectively. n is 0 and 1, n is 1 and 2, n is 2 and 3, n is 3 and 4, and n is 4 and 5.

Has a spacing of 2π / 12 (30 °) in the complex plane. But when n is 5 and 0

Has a spacing of 14π / 12 (210 °) in the complex plane. therefore,

Are not placed at equal intervals in the complex plane. In this case, the DM-RS sequence may be degraded orthogonal. In this case

Is odd and the number of subcarriers (

Occurs when) is a multiple of 6 and not a multiple of 12.

In order to prevent such a case, when the DM-RS sequence is allocated by the IFDMA method, the reference signal mapping unit 822 substitutes the following Equation 6 or 7 instead of Equation 1 related to DM-RS sequence allocation. DM-RS sequence can be allocated.

[Equation 6]

[Equation 7]

Comparing Equation 1 with Equation 6 and Equation 7, in Equation 1

In Equations 6 and 7

Will change to This is an example of when N = 2 and generally

It can be expressed as. This indicates that when the DM-RS sequence is allocated by the IFDMA method, the length of the sequence allocated to the same bandwidth is reduced.

In Equations 6 and 7, the number of subcarriers to which the DM-RS is allocated

Is a multiple of 12

Is calculated in the same manner as in equation (1). In comparison,

Is not a multiple of 12

Is

or

Is calculated.

Is not a multiple of 12

Is an even number

Is calculated equal to Equation 1,

Is not a multiple of 12 (for example,

Is 6, 18, 30, 42, etc.)

Is odd

Is calculated differently from Equation 1, and the DM-RS sequence calculated using this can guarantee orthogonality.

For example, when Equation 7 is applied, one resource block is allocated to a specific terminal, and a DM-RS sequence is allocated only to six subcarriers (n = 0 to 5) out of a total of 12 subcarriers.

Consider when = 1. By equation (7)

Is calculated as 4π / 12,

Have values of 0, 4π / 12, 8π / 12, 12π / 12, 16π / 12, and 20π / 12, respectively. therefore,

Are located at equal intervals of 4π / 12 (60 °) in the complex plane. The calculated DM-RS sequence can maintain orthogonality.

In Equation 6 and Equation 7

or

Is an example where N = 2, and generally

or

It can be expressed as.

Alternatively, when allocating a DM-RS sequence using the IFDMA method, the reference signal mapping unit 822 may allocate the DM-RS sequence using Equation 8 below instead of Equation 1 associated with DM-RS sequence allocation. Can be.

[Equation 8]

Comparing Equation 1 and Equation 8, in Equation 1

In equation (8)

Will change to This is an example of when N = 2 and generally

In Equation 1

In Equation 8

Will change to This is an example of when N = 2 and generally

It can be expressed as. In this case, orthogonality may be maintained even when the length of the DM-RS sequence is not a multiple of 12.

Alternatively, when allocating a DM-RS sequence in the IFDMA scheme, the reference signal mapping unit 822 may allocate the DM-RS sequence using Equation 9 below instead of Equation 1 related to DM-RS sequence allocation. Can be.

[Equation 9]

Comparing Equation 1 and Equation 8, in Equation 1

In equation (8)

Will change to This is an example of when N = 2 and generally

In Equation 1

In Equation 9

Will change to This is an example of when N = 2 and generally

When the DM-RS sequence is allocated through all subcarriers of the resource block to which the PUSCH is allocated without using the IFDMA scheme, the reference signal mapping unit 822 may allocate the DM-RS sequence using Equation 1. . When the DM-RS sequence is allocated through some subcarriers having a constant interval among the subcarriers of the resource block to which the PUSCH is allocated using the IFDMA scheme, the reference signal mapping unit 822 may use one of Equations 6 to 9. DM-RS sequence can be allocated by using.

In the above-described example, the orthogonality is guaranteed using the IFDMA scheme, but it is also possible to simultaneously apply the OCC and the IFDMA scheme. For example, in case of using OCC, orthogonality can be guaranteed between two signals. In case of using IFDMA method, orthogonality can be guaranteed between N signals, and in general, orthogonality can be guaranteed between 2N signals. .

In the above example, the uplink DM-RS has been described by way of example, but the present invention is not limited thereto and may be applied to other uplink reference signals. That is, when the same type or different types of uplink reference signals transmitted from different terminals are transmitted through the same resource, when the orthogonality needs to be guaranteed to distinguish such uplink reference signals, embodiments of the present invention Can be applied. For example, when one terminal transmits a DM-RS and another terminal transmits an SRS on the same resource, the DM-RS and the SRS may be transmitted through different subcarriers to ensure orthogonality between them.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited thereto. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application claims priority to US Patent Application No. 10-2011-0080916, filed with Korea on August 12, 2011, pursuant to Article 119 (a) (35 USC § 119 (a)). All content is incorporated by reference in this patent application. In addition, if this patent application claims priority for the same reason for countries other than the United States, all its contents are incorporated into this patent application by reference.

Claims

A reference signal information transmitting unit for transmitting region setting information on an area for allocating an uplink reference signal through some subcarriers having a predetermined interval among subcarriers through a radio resource control (RRC) or a physical broadcasting channel (PBCH); And

And a resource allocation information transmitter for transmitting resource allocation information for a resource region through which a specific terminal transmits an uplink signal.
The method of claim 1,

The reference signal information transmitting unit may include the uplink represented by the index of the starting resource block or resource block group and the number of resource blocks or resource block groups in the region to which the uplink reference signal is allocated. Generate the region setting information based on the size of the region to which the reference signal is allocated, generate the region setting information by expressing the region to which the uplink reference signal is allocated in two parts, or allocate the uplink reference signal. And a region setting information is generated by expressing the region to be represented as a bitmap in units of resource blocks or resource block groups.
Transmitting reference signal information for transmitting region setting information on an area for allocating an uplink reference signal through some subcarriers having a predetermined interval among subcarriers through a radio resource control (RRC) or a physical broadcasting channel (PBCH); And

And transmitting resource allocation information for the resource region for transmitting the uplink signal by a specific terminal.
The method of claim 3, wherein

In the transmitting of the reference signal information, the uplink represented by the index of the starting resource block or resource block group and the number of resource blocks or resource block groups in the region to which the uplink reference signal is allocated. The region setting information is generated based on the size of the region to which the link reference signal is allocated, or the region setting information is generated by expressing the region to which the uplink reference signal is allocated in two parts, or the uplink reference signal is And a region setting information is generated by expressing the allocated region as a bitmap in units of resource blocks or resource block groups.
When a resource region for transmitting an uplink signal is included in an area for allocating an uplink reference signal through some subcarriers having a predetermined interval among subcarriers, a reference signal for allocating an uplink reference signal to the some subcarriers A mapping unit; And

A reference signal transmitter for transmitting the uplink reference signal;

And information on the region for allocating an uplink reference signal through some subcarriers having a predetermined interval among the subcarriers is received through RRC (Radio Resource Control) or PBCH (Physical Broadcasting Channel).
The method of claim 5,

The some subcarriers are indicated by a signal transmitted from a transmitting end or determined based on an ID of a cell to which the terminal belongs.
The method of claim 5,

The information on the region is the uplink represented by the index of the starting resource block or resource block group and the number of resource blocks or resource block groups of the region to which the uplink reference signal is allocated. A resource block or a resource block group unit may be generated based on a size of an area for allocating a reference signal, generated by expressing an area for allocating the uplink reference signal in two parts, or an area for allocating the uplink reference signal. The terminal characterized in that it is generated by expressing a bitmap.
A sequence of uplink reference signals through some subcarriers having a constant interval among subcarriers in a resource region according to the following equation (
A reference signal mapping unit for assigning; And

A terminal comprising a reference signal transmitter for transmitting the uplink reference signal.

In the above equation,
Is the base sequence,
Is the number of subcarriers through which the uplink reference signal is transmitted,
Is a parameter passed through RRC,
Is a parameter passed through DCI,
Is a parameter determined according to the cell ID and the slot number,
Is an orthogonal sequence,
Indicates the layer index.
When a resource region for transmitting an uplink signal is included in an area for allocating an uplink reference signal through some subcarriers having a predetermined interval among subcarriers, a reference signal for allocating an uplink reference signal to the some subcarriers Mapping step; And

A reference signal transmission step of transmitting the uplink reference signal,

The information on the region for allocating an uplink reference signal through some subcarriers having a predetermined interval among the subcarriers is received through a radio resource control (RRC) or a physical broadcasting channel (PBCH). Signal transmission method.
The method of claim 9,

The some subcarriers are indicated by a signal transmitted from a transmitting end or determined based on an ID of a cell to which the terminal belongs.
The method of claim 9,

The information on the region is the uplink represented by the index of the starting resource block or resource block group and the number of resource blocks or resource block groups of the region to which the uplink reference signal is allocated. A resource block or a resource block group unit may be generated based on a size of an area for allocating a reference signal, generated by expressing an area for allocating the uplink reference signal in two parts, or an area for allocating the uplink reference signal. The terminal characterized in that it is generated by expressing a bitmap.
A sequence of uplink reference signals through some subcarriers having a constant interval among subcarriers in a resource region according to the following equation (
Assigning a reference signal mapping step; And

And a reference signal transmission step of transmitting the uplink reference signal.

In the above equation,
Is the base sequence,
Is the number of subcarriers through which the uplink reference signal is transmitted,
Is a parameter passed through RRC,
Is a parameter passed through DCI,
Is a parameter determined according to the cell ID and the slot number,
Is an orthogonal sequence,
Indicates the layer index.