KR20100137391A - Method of transmitting uplink demodulation reference signal - Google Patents

Abstract

PURPOSE: In the reference signal transmission method for the uplink demodulation is the inside a slot, the uplink demodulation performance is kept in LTE-advanced by using two or more DFT-s-OFDM symbols. CONSTITUTION: In the first slot, the sequence element C1, 0 or the C30 which is similar about the subcarrier 0, 1 becomes in case of the transmission antenna 1 and 3 with the use(301). The sequence element C1, 1 or the C3, 1 which is similar about the subcarrier 2,3 becomes with the use(302). In case of the transmission antenna 2 and 4, the sequence element C20 or C4, 0 becomes about the subcarrier 0 with the use(303).

Description

Method of transmitting a reference signal for uplink demodulation {Method of transmitting uplink demodulation reference signal}

The present invention relates to a method for transmitting uplink demodulation reference signals, and more particularly, to a method for transmitting uplink demodulation reference signals considering multiple inputs and outputs applicable to 3GPP LTE-advanced.

Currently, the standards created by 3GPP (3rd Generation Partnership Project) and IEEE 802.16, which are international wireless transmission technology standardization organizations, consider a case where a base station has up to four transmit antennas (ie, downlink transmissions). However, there will be a demand for higher data rates in the future, and accordingly, multiple input multiple outputs (MIMO) must be performed in the uplink. In order to perform multiple input / output in uplink, a modification to a reference signal (RS) design method is necessary.

FIG. 1 is a conceptual diagram of an uplink subframe for explaining a structure of transmitting a reference signal for uplink demodulation of a current 3GPP Long-Term Evolution (LTE).

That is, FIG. 1 illustrates a physical uplink shared channel (PUSCH) demodulation for uplink presented by 3GPP LTE Release 8 TS36.211 v8.6.0 "Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation" The design structure of the DM-RS (Demodulation RS) is described.

FIG. 1 illustrates a case in which one slot is composed of seven symbols (DFT-s-OFDM symbols; DFT-spread-Orthogonal Frequency Division Multiplexing) (when using a normal CP), and one subframe (subframe); 100 is composed of two slots 101 and 102, and a DM-RS is transmitted in the fourth symbol of one slot. That is, the DM-RS is transmitted in the fourth symbol 111 of the first slot 101 and the DM-RS is transmitted in the fourth symbol 112 of the second slot 102. For reference, the time length of one slot is 0.5ms.

In case that N _SC uplink frequency domain resources are allocated to a given user, one demodulation reference signal (DM-RS) symbol is used as a time domain in a slot. And, the length of the reference signal sequence for each transmit antenna is N _SC .

In this case, in one subframe, the DM-RS for the first slot and the DM-RS for the second slot may be transmitted using subcarriers of the same location according to the presence or absence of frequency slot hopping. It may be transmitted using subcarriers of the location.

Looking at the above description and the current uplink DM-RS transmission structure illustrated in FIG. 1, since the DM-RS transmission when the multi-input / output is introduced in the uplink of LTE, the multi-input / output is introduced in the uplink. In this case, the transmission method of the orthogonal DM-RS for each layer is needed. In addition, LTE-advanced, the next version of LTE, is defined to support higher travel speeds (eg 350 km / h according to requirements) than LTE, resulting in a higher Doppler spread environment than LTE systems. As a result, it is satisfactory with the current DM-RS transmission structure, but it becomes difficult to expect performance. This is because the fading channel can change rapidly even within one slot period (0.5 ms) at a high moving speed. Therefore, it is also necessary to improve the DM-RS transmission method in view of such a high moving speed.

Disclosure of Invention An object of the present invention is to provide a method for transmitting an uplink demodulation reference signal capable of supporting even a high moving speed in consideration of multiple inputs and outputs applied to uplink.

According to an aspect of the present invention, a method for transmitting an uplink demodulation reference signal according to an aspect of the present invention provides a demodulation reference for each slot in uplink in which a first slot and a second slot exist in one subframe. A method of transmitting a signal (DM-RS), the method comprising: determining the first DM-RS sequences transmitted in the first slot for each antenna participating in the uplink transmission, for at least some of the antennas participating in the uplink transmission The first DM-RS sequence transmitted by each antenna in the first slot is multiplied by -1, or the first DM-RS sequence transmitted by each antenna in the first slot is transmitted by the second DM-RS sequence transmitted by the second slot. Determining that the device has been cyclically shifted, and transmitting the determined first DM-RS sequence in a first slot and transmitting the determined second DM-RS sequence in a second slot. Can be configured.

According to another aspect of the present invention, a method for transmitting an uplink demodulation reference signal according to another aspect of the present invention provides a demodulation for each slot in uplink in which a first slot and a second slot exist in one subframe. A method of transmitting a reference signal (DM-RS), wherein the first DM-RS sequences to be transmitted in the first slot for each antenna participating in the uplink transmission, the first DM-RS sequence of at least some of the antennas participating in the uplink transmission The DM-RS sequence consists of the same sequence elements in adjacent subcarrier pairs, and the first DM-RS sequence of the remaining part of the antennas participating in the uplink transmission consists of sequence elements having only different signs between adjacent subcarriers. Determining the first DM-RS sequence, the second DM-RS sequence for transmitting at least some of the antennas participating in the uplink transmission in the second slot Determining the number of times by multiplying the first DM-RS sequence transmitted by each antenna in the first slot by -1, or by cyclically shifting the first DM-RS sequence transmitted by each antenna in the first slot; and The determined first DM-RS sequence may be transmitted in a first slot, and the determined second DM-RS sequence may be transmitted in a second slot.

According to another aspect of the present invention, a method for transmitting an uplink demodulation reference signal according to another aspect of the present invention provides a method for transmitting an uplink demodulation reference signal in a terminal. A demodulation reference transmitted in one slot, based on the step of sharing information on the number of DFT-s-OFDM symbols to which a reference signal is transmitted with the base station and the information on the number of shared DFT-s-OFDM symbols. It may comprise the step of constructing a signal.

Here, the step of sharing information on the number of DFT-s-OFDM symbols in which the demodulation reference signal is transmitted with a base station is performed by the terminal to the base station receiving the demodulation reference signal using uplink control information. The demodulation reference signal may be configured to convey information on the number of DFT-s-OFDM symbols transmitted.

Here, the step of sharing information on the number of DFT-s-OFDM symbols in which the demodulation reference signal is transmitted with a base station is performed by the base station to the terminal transmitting the demodulation reference signal using downlink control information. The demodulation reference signal may be configured to convey information on the number of DFT-s-OFDM symbols transmitted.

According to another aspect of the present invention, a method for transmitting an uplink demodulation reference signal according to another aspect of the present invention includes two DFT-s-OFDM symbols (one symbol) in one slot present in a subframe. And determining a first DM-RS sequence transmitted by the first symbol for each antenna participating in the uplink transmission, and transmitting the demodulation reference signal to the second symbol. Multiply the first DM-RS sequences transmitted by each antenna in the first symbol by -1 for at least a portion of the second DM-RS sequence transmitted in the second symbol, or transmit by each antenna in the first symbol Determining that the first DM-RS sequence has been cyclically shifted and the determined first DM-RS sequence is transmitted in the first symbol, and the determined second DM-RS sequence is transmitted to the second shim And transmitting from the ball.

According to another aspect of the present invention, a method for transmitting an uplink demodulation reference signal according to another aspect of the present invention includes two DFT-s-OFDM symbols (a first symbol and a second symbol) for each slot present in a subframe. A method of transmitting an uplink demodulation reference signal for transmitting a demodulation reference signal, comprising: a first DM-RS sequence transmitted in the first symbol by applying a different cyclic shift value for each antenna participating in uplink transmission Determining second cyclically shifted sequences of second DM-RS sequences cyclically shifted by a predetermined offset with respect to the first DM-RS sequences, and at least some of the antennas participating in the uplink transmission. For example, the second DM-RS sequence is determined by multiplying each of the configured second DM-RS sequences by -1. Determining a DM-RS sequence as a second DM-RS sequence and transmitting the determined first DM-RS sequence in the first symbol, and transmitting the determined second DM-RS sequence in the second symbol. It may comprise a step.

Here, in the determining of the first DM-RS sequence, the first DM-RS sequence is a first DM-RS sequence of a k (k is an integer) slot, and the first DM-RS sequence The first DM of the k + 1th slot, which is the next slot of the kth slot, when the transmitting antenna index m0 is next to the transmitting antenna index m0 in the order in which the indexes of the transmitting antennas are arranged according to the cyclic shift value applied. The first DM-RS sequence may be determined such that the transmit antenna index m1 does not exist after the transmit antenna index m0 in the order of indexing of the transmit antennas according to the cyclic shift value applied to the -RS sequences. .

Here, in the step of configuring the second DM-RS sequences of the cyclic shifted cyclic shifted by a predetermined offset value for the first DM-RS sequences, the predetermined offset value is the number of the serving cell of the terminal And the first DM-RS sequence may be determined according to an index value of a slot in which the first DM-RS sequence is transmitted.

By using the uplink DM-RS transmission method according to the present invention as described above, orthogonality between DM-RS sequences transmitted for each antenna can be maintained when multiple input / output (MIMO) is applied in uplink transmission.

In addition, when transmitting DM-RS through two or more DFT-s-OFDM symbols in a slot constituting one subframe in uplink transmission, LTE-advanced is required to support a higher mobile speed than the current LTE requirement. In the uplink demodulation performance can be maintained.

FIG. 1 is a conceptual diagram of an uplink subframe for explaining a structure of transmitting a reference signal for uplink demodulation of a current 3GPP Long-Term Evolution (LTE).
2 is a conceptual diagram illustrating an example of a method of configuring a reference signal for uplink demodulation according to the present invention.
3 is a conceptual diagram illustrating another example of a method of configuring a reference signal for uplink demodulation according to the present invention.
4 is a conceptual diagram illustrating in more detail another example of a method of configuring a reference signal for uplink demodulation according to the present invention.
5 and 6 are conceptual diagrams illustrating a subframe for explaining another example of a method of configuring a reference signal for uplink demodulation according to the present invention.
7 is a conceptual diagram illustrating a concept of applying an orthogonal cover code in another example of a method of configuring a reference signal for uplink demodulation according to the present invention.
FIG. 8 is a conceptual diagram illustrating a method of using a cyclic shift value and an orthogonal cover code for an arbitrary cell for four transmission antennas in another example of a method of configuring an uplink demodulation reference signal according to the present invention.
FIG. 9 is a conceptual diagram illustrating a method of using a cyclic shift value and an orthogonal cover code for an arbitrary cell for two transmit antennas in another example of a method for transmitting an uplink demodulation reference signal according to the present invention.
10 is a flowchart illustrating an example of an uplink DM-RS transmission method according to the present invention.
11 is a flowchart illustrating another example of an uplink DM-RS transmission method according to the present invention.
12 is a flowchart for explaining another example of a method for transmitting uplink DM-RS according to the present invention.
13 is a flowchart illustrating another example of a method for transmitting uplink DM-RS according to the present invention.
14 is a flowchart illustrating another example of a method for transmitting uplink DM-RS according to the present invention.

As the present invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description.

However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

As used herein, the term 'terminal' includes a mobile station (MS), a user equipment (UE), a user terminal (UT), a wireless terminal, an access terminal (AT), a terminal, a subscriber unit, A subscriber station (SS), wireless device, wireless communication device, wireless transmit / receive unit (WTRU), mobile node, mobile or other terms may be referred to. Various embodiments of the terminal may be photographed such as a cellular telephone, a smart phone having a wireless communication function, a personal digital assistant (PDA) having a wireless communication function, a wireless modem, a portable computer having a wireless communication function, or a digital camera having a wireless communication function. Devices, gaming devices with wireless communications capabilities, music storage and playback appliances with wireless communications capabilities, internet appliances with wireless Internet access and browsing, as well as portable units or terminals incorporating combinations of such functions. However, the present invention is not limited thereto.

As used herein, a 'base station' generally refers to a fixed point for communicating with a terminal, and includes a base station, a Node-B, an eNode-B, and a BTS. It may be called other terms such as a transceiver system, an access point.

In addition, the method for transmitting a demodulation reference signal and a control signal for uplink multiple input / output (MIMO) described in the present invention may be applied to a relay node as well as a conventional base station.

Hereinafter, with reference to the accompanying drawings, it will be described in detail a preferred embodiment of the present invention. In describing the present invention, in order to facilitate the overall understanding, the same reference numerals are used for the same elements in the drawings, and redundant description of the same elements is omitted.

The uplink DM-RS transmission method according to the present invention corresponds to a DM-RS transmission method using uplink DM-RS configuration methods according to the present invention described below. For convenience of description, a method of configuring uplink DM-RS according to the present invention will be described first, and a method of transmitting uplink DM-RS according to the present invention using these will be described below.

In addition, hereinafter, for convenience of description, various uplink DM-RS configuration methods according to the present invention will be described separately, but the uplink DM-RS transmission method according to the present invention is described with each DM-RS configuration method independently. In addition to the case used, it may include a case used in combination with each other.

Uplink DM-RS configuration method # 1 according to the present invention

2 is a conceptual diagram illustrating an example of a method of configuring a reference signal for uplink demodulation according to the present invention.

As illustrated in FIG. 1, FIG. 2 is a conceptual diagram assuming a case of transmitting a DM-RS in one DFT-s-OFDM symbol in one slot, similar to the uplink DM-RS configuration of the conventional LTE.

Referring to FIG. 1 in parallel, one of the methods of configuring an uplink demodulation reference signal (Uplink DM-RS) proposed by the present invention is a DM-RS for a first slot 101 in a subframe 100 in a time domain. Orthogonal Cover Code (OCC) is used for the DM-RS 112 for the 111 and the second slot 102. That is, the orthogonal cover code is applied in the time domain.

Referring to FIG. 2, each row describes a sequence element transmitted for each antenna for each FDR (Frequency Domain Resource). FIG. 2 illustrates a multiple input and multiple output in which four antennas participate in transmission in uplink.

For example, for transmit antenna 1, a sequence (C _1,0 , C _1,1 , C _1,2 , ..., C _{1, Nsc-1} ; 201) is used, and for transmit antenna 2, a sequence ( C _2,0 , C _2,1 , C _2,2 , ..., C _{2, Nsc-1} ; 202, and for transmit antenna 3, the sequence (C _3,0 , C _3,1 , C _3,2 , ..., C _{3, Nsc-1} ; 203, and for transmit antenna 4, the sequence (C _4,0 , C _4,1 , C _4,2 , ..., C _{4, Nsc-1} 204 illustrates an uplink DM-RS transmission in a first slot of a subframe.

In the method of configuring an uplink DM-RS according to the present invention described with reference to FIG. 2, the transmit antennas 1 and 2 transmit the same sequence elements 211 and 212 as those transmitted from the first slot 101 in the second slot 102. (Ie, 211 and 212 are the same sequence as 201 and 202, respectively), and transmit antennas 3 and 4 multiply the sequence transmitted in the first slot 101 by -1 to transmit in the second slot 102. (213, 214) (ie, 213 and 214 are sequences of 203 and 204 times −1, respectively).

에 대해서,

(정수)만큼 사이클릭 쉬프트시킨 시퀀스는

와 같이 나타낼 수가 있다. In addition, the sequence used in the second slot for each transmit antenna may use a cyclic shifted sequence of the sequence used in the first slot. That is, what sequence

about,

The sequence cyclically shifted by (integer)

Can be expressed as:

Meanwhile, FIG. 2 illustrates a case in which four antennas are used in uplink transmission. However, even when two antennas participate in the transmission, an uplink DM-RS transmission method may be configured in a similar manner.

For example, in FIG. 2, the transmit antenna 1 uses (C _1,0 , C _1,1 , C _1,2 , ..., C _{1, Nsc-1} ; 201) in the first slot and ( C _1,0 , C _1,1 , C _1,2 , ..., C _{1, Nsc-1} ; 211), and transmit antenna 2 is (C _3,0 , C _3,1 in the first slot). , C _3,2 , ..., C _{3, Nsc-1} ; 203) and in the second slot (-C _3,0 , -C _3,1 , -C _3,2 , ...,- C _{3, Nsc-1} ; 213). In this case, as in the above-described four-antenna transmission, the sequence used by each transmit antenna in the second slot may use the same sequence as the sequence used in the first slot, or the cyclic shifted sequence of the sequence used in the first slot may be used. Can also be used.

By applying the method using the Orthogonal Cover Code (OCC) described above, the uplink DM-RS can be configured to be suitable for multiple input / output transmission by further enhancing the orthogonality of the sequence for each antenna transmitted per slot. . That is, since the separation degree of the DM-RS signal is increased for each antenna at the receiving end, demodulation performance of the received data may be improved.

Uplink DM-RS configuration method # 2 according to the present invention

3 is a conceptual diagram illustrating another example of a method of configuring a reference signal for uplink demodulation according to the present invention.

The uplink DM-RS configuration method described in FIG. 2 uses orthogonal cover codes only for time domains spanning the first slot and the second slot in one subframe, but the uplink DM described in FIG. The RS configuration method may be described as using an orthogonal cover code (OCC) not only in the time domain but also in the frequency domain.

Referring to Figure 3, a sequence of length N _SC / 2 is used at each antenna. That is, in the case of the transmission antenna 1, the sequence (C _1,0 , C _1,1 , C _1,2 , ..., C _{1, Nsc / 2-1} ) is used. In addition, two neighboring subcarriers (subcarriers) use the same sequence elements or use only sequence codes with different signs.

For example, in the first slot, if the transmission antennas 1 and 3 are the same sequence of elements C _1,0 or same sequence element using the C _3,0 (301), and also the sub-carriers 2, 3 with respect to the sub-carrier ₁ 0,1 C (302) using _{, 1} or C _3,1 . On the other hand, in case of transmitting antennas 2 and 4, sequence element C _2,0 or C _4,0 is used for subcarrier 0 (303), but sequence element -C _2,0 or -C having a different sign for subcarrier 1 is used. _4,0 is used (ie, means OCC application in the frequency domain).

Meanwhile, in the second slot, the transmit antennas 1 and 2 transmit the same sequence elements as transmitted in the first slot, and the transmit antennas 3 and 4 may be configured to multiply the sequence elements transmitted in the first slot by -1. have. This may mean application of OCC in the time domain as described with reference to FIG. 2.

에 대해서,

(정수)만큼 사이클릭 쉬프트시킨 시퀀스는

와 같이 나타낼 수가 있다. In addition, the sequence used in the second slot for each transmit antenna may use a cyclic shifted sequence of the sequence used in the first slot. That is, what sequence

about,

The sequence cyclically shifted by (integer)

Can be expressed as:

Meanwhile, although FIG. 3 illustrates a case in which four antennas are used in uplink transmission, an uplink DM-RS transmission method may be configured in a similar manner even when two antennas participate in the transmission.

4 is a conceptual diagram illustrating in more detail another example of a method of configuring a reference signal for uplink demodulation according to the present invention.

Referring to FIG. 4, only the example of FDR index 0,1 is described separately in FIG. 3. That is, in FDR index 1 of the first slot, transmit antennas 1 and 3 transmit the same sequence elements as transmitted at FDR index 0, and transmit antennas 2 and 4 multiply sequence elements multiplied by -1 from FDR index 0. send.

On the other hand, in the second slot, the transmit antennas 1 and 2 transmit the same sequence elements as transmitted in the first slot, and the transmit antennas 3 and 4 transmit the sequence elements multiplied by -1 to those transmitted in the first slot.

As described above, by using an orthogonal cover code (OCC) in the time domain and the frequency domain, the uplink DM-RS is further enhanced to be suitable for multiple input / output transmission by further enhancing the orthogonality of the sequence for each antenna transmitted per slot. The transmission method can be configured.

Uplink DM-RS configuration method # 3 according to the present invention

5 and 6 are conceptual diagrams illustrating a subframe for explaining another example of a method of configuring a reference signal for uplink demodulation according to the present invention.

LTE-advanced, which is currently being standardized as a follow-up version of LTE, is defined to support higher travel speeds (eg, 350 km / h according to requirements) compared to LTE, which results in a higher Doppler spread than LTE systems. Environment), it is satisfactory with the current DM-RS transmission structure, but it is difficult to expect performance. This is because the fading channel can change rapidly even within one slot period (0.5 ms) at a high moving speed. To this end, it may be necessary to transmit the DM-RS through a plurality of symbols instead of one OFDM symbol (DFT-s-OFDM symbol) even in one slot.

Referring to FIG. 5, a method of transmitting a reference signal for uplink demodulation when one slot includes seven DFT-s-OFDM symbols (when a normal CP is applied) is described. That is, uplink demodulation reference signals may be transmitted in the second OFDM symbols 511 and 513 and the sixth OFDM symbols 512 and 514 in one slot 501 or 502.

Meanwhile, referring to FIG. 6, a method of transmitting an uplink demodulation reference signal when one slot includes six OFDM symbols (DFT-s-OFDM symbols) (when an extended CP is applied) is described. It is described that the uplink demodulation reference signal is transmitted in the second OFDM symbol 611, 613 and the fifth OFDM symbol 612, 614 in the slot 601 or 602.

As such, when uplink DM-RS is transmitted in two OFDM symbols in one slot, an orthogonal cover code is used in a manner similar to that described in FIG. 2 above, or an uplink DM-RS is used without using an orthogonal cover code. May be configured to be transmitted.

7 is a conceptual diagram illustrating a concept of applying an orthogonal cover code in another example of a method of configuring a reference signal for uplink demodulation according to the present invention.

Referring to FIG. 7, a concept in which an orthogonal cover code is used in a manner similar to that described in FIG. 2 when uplink DM-RS is transmitted in two OFDM symbols in one slot as described above is described. .

In this case, each transmit antenna uses a sequence of length N _SC , and transmit antennas 3 and 4 transmit the sequence element transmitted by the first DM-RS in one slot and multiply the sequence element by -1 to the second DM-RS in one slot. Means to send.

That is, the application of the orthogonal cover code described in FIG. 7 describes that the application of the orthogonal cover code described in FIG. 2 is applied to the DM-RS sequences of the first slot and the second slot. This is for explaining that it is applied to one DM-RS sequence and a second DM-RS sequence.

In addition, for each transmit antenna, the sequence used in the second slot may use a cyclic shifted sequence of the sequence used in the first slot. FIG. 7 illustrates a case in which four antennas are used in uplink transmission. Although illustrated, the uplink DM-RS transmission method may be configured in a similar manner when two antennas participate in transmission.

Uplink DM-RS configuration method # 4 according to the present invention

Another example of a method of configuring a reference signal for uplink demodulation according to the present invention is to transmit a DM-RS in two OFDM symbols (DFT-s-OFDM) symbols in one slot as described in FIGS. 5 and 6. In this case, a basic sequence, a cyclic shift, and an orthogonal cover code are applied to a sequence transmitted to each transmit antenna.

A detailed description of the uplink DM-RS transmission method is as follows.

라고 한다. 이 시퀀스에 대한 한 가지 예는 자도프-추(Zadoff-Chu) 시퀀스이다.First, the basic sequence used as an uplink DM-RS

It is called. One example of this sequence is the Zadoff-Chu sequence.

로 정의될 수 있다. 각 송신 안테나에 대한 복조용 디모듈레이션 레퍼런스 신호 시퀀스는 사이클릭 쉬프트 값

를 다르게 적용하는 것이다. 즉, 송신 안테나 m(m=1, 2, ...)에 대한 DM-RS 시퀀스는 사이클릭 쉬프트

을 사용하는 것이다. 이때, 실제 시퀀스는

와 같이 나타낼 수 있다. And the sequence which cyclically shifted this basic sequence by a (an integer)

It can be defined as. The demodulation demodulation reference signal sequence for each transmit antenna is the cyclic shift value.

Is to apply differently. That is, the DM-RS sequence for transmit antenna m (m = 1, 2, ...) is cyclic shifted

Is to use In this case, the actual sequence

Can be expressed as:

FIG. 8 is a conceptual diagram illustrating a method of using a cyclic shift value and an orthogonal cover code for an arbitrary cell for four transmission antennas in another example of a method of configuring an uplink demodulation reference signal according to the present invention.

The method of using the cyclic shift (CS) and the orthogonal cover code (OCC) for each transmit antenna proposed in the present invention is as described below, and will be described with reference to FIG. 8 in parallel.

1) 4 transmitting antennas

를 사용한다고 가정한다. 즉, 송신 안테나 m은 사이클릭 쉬프트

를 사용한다고 가정한다. 이때, 사이클릭 쉬프트 및 직교 커버 코드를 사용하는 규칙들은 다음과 같다.
For the first DM-RS in the i-th cell, the k-th slot, the cyclic shift for four transmit antennas

Suppose we use That is, the transmitting antenna m is a cyclic shift

Suppose we use In this case, the rules for using the cyclic shift and orthogonal cover codes are as follows.

를 사용하는 것이다.
Rule 1) For the second DM-RS of the same slot, the cyclic shift offset as shown in Equation 1 below.

Is to use

[Equation 1]

는 셀 번호 i와 슬롯 인덱스 k에 따라서 달라지게 된다. Cyclic shift offset

Depends on cell number i and slot index k.

For example, referring to FIG. 8, if the cyclic shift value used for each of four antennas for the first DM-RS in the slot is [0, 6, 3, 9], for example, the cyclic shift offset is performed in the second DM-RS in the slot. 8 (FIG. 8 exemplarily illustrates the case in which 8 is applied as the cyclic shift offset, but the cyclic shift offset that is actually applied may vary). Thus, the cyclic shift value of [8, 2, 11, 5] is applied. It is illustrated to be applied for each antenna. In this case, in the case of antenna 2 and antenna 4, since offset 8 is applied and the shift value is cyclic, cyclic shifts 2 and 5 are applied to the sequence of the second DM-RS.

Rule 2) When the transmit antenna index is aligned according to the cyclic shift value, if the random transmit antenna index m0 is followed by m1 in the slot index k, the slot index k + 1 does not allow m1 after the transmit antenna index m0. Apply the click shift value.

For example, if the transmit antenna index is aligned according to the cyclic shift value at the slot index k, it is assumed to be (1, 3, 2, 4). Then, in the slot index k + 1, when the transmit antenna index is aligned according to the cyclic shift value, the transmit antenna 1 should not be 3 after the transmit antenna 1, the 2 after the transmit antenna 3, and the 4 after the transmit antenna 2 Is not, and there is no 1 after transmit antenna 4.

One such example is to apply the cyclic shift value for each antenna of the slot index k + 1 to be (1, 4, 2, 3). The reason for configuring the cyclic shift value at the slot index k + 1 as described above is to randomize the interference generated in the channel estimation between the antennas at the slot index k and the slot index k + 1. That is, the slot index k has a small difference in the cyclic shift value between the antenna 1 and the antenna 3, so that the antenna 3 has a great influence on the channel estimation of the transmission antenna 1. If the antenna 1 is followed by the cyclic shift value of the antenna 3 even in the slot index k + 1, the antenna 3 may affect the channel estimation for the antenna 1 even in the slot index k + 1. Therefore, rule 2 is applied to randomize slot-to-antenna interference during channel estimation for each slot.

Rule 3) Two transmit antennas use orthogonal cover code 1 (OCC1), and the other two transmit antennas use orthogonal cover code 2 (OCC2). The indexes of the two transmit antennas using the orthogonal cover code are used differently depending on the cell number and the slot number. One example of an orthogonal cover code is to use (1,1) for OCC1 and (1, -1) for OCC2.

Referring to FIG. 8, in the slot k, transmit antennas 1 and 2 use orthogonal cover code 1 (OCC1), and in the next slot, transmit antennas 1 and 3 use orthogonal cover code 2 (OCC2). As described above, the transmission antenna combinations of the orthogonal cover codes 1 and 2 are used differently according to the cell number and the slot number.

Therefore, in another example of the uplink DM-RS transmission method according to the present invention, a method of determining a cyclic shift value and an orthogonal cover code is determined to satisfy all three rules, and another method is one of the three rules. To satisfy the rules.

2) 2 transmitting antennas

를 사용한다고 가정한다. 즉, 송신 안테나 m은 사이클릭 쉬프트

를 사용한다고 가정한다. For the first DM-RS in the i-th cell and the k-th slot, two transmission antennas are cyclic shifted

Suppose we use That is, the transmitting antenna m is a cyclic shift

Suppose we use

FIG. 9 is a conceptual diagram illustrating a method of using a cyclic shift value and an orthogonal cover code for an arbitrary cell for two transmit antennas in another example of a method for transmitting an uplink demodulation reference signal according to the present invention.

Referring to FIG. 9 in parallel, rules for using a cyclic shift and an orthogonal cover code when two transmit antennas are described will be described.

를 사용하는 것이다.
Rule 1) For the second DM-RS of the same slot, the cyclic shift offset as shown in Equation 2 below.

Is to use

[Equation 2]

은 셀 번호 i 및 슬롯 인덱스 k에 따라서 달라지게 된다.
Cyclic shift offset

Depends on cell number i and slot index k.

Rule 2) One transmit antenna uses orthogonal cover code 1 (OCC1), and the other transmit antenna uses orthogonal cover code 2 (OCC2). The index of the transmit antenna using each orthogonal cover code is used differently according to the cell number and the slot number. One example of an orthogonal cover code is to use (1,1) for OCC1 and (1, -1) for OCC2. Another example is to use (1,1) the same for OCC1 and OCC2.

9, in slot k, transmit antenna 1 uses orthogonal cover code 1 (OCC1), and in the next slot, transmit antenna 2 uses orthogonal cover code 1 (OCC1). As described above, the transmission antenna combinations of the orthogonal cover codes 1 and 2 are used differently according to the cell number and the slot number.

Therefore, in another example of the uplink DM-RS transmission method according to the present invention, the method of determining the cyclic shift value and the orthogonal cover code is to satisfy both of the above rules, and the other method is the above two rules. To satisfy as many rules as possible.

Uplink DM-RS Transmission Method According to the Present Invention

According to the uplink DM-RS configuration method according to the present invention described above, a terminal may configure an uplink DM-RS and transmit it to a base station.

Hereinafter, an uplink DM-RS transmission method according to the present invention for transmitting an uplink DM-RS configured according to the uplink DM-RS configuration method according to the present invention to a base station will be described. Since the uplink DM-RS transmission method according to the present invention is configured by applying the above-described DM-RS configuration method described with reference to FIGS. 2 to 9, the flowcharts related to the following transmission method are shown in FIG. 9 to 9 may be described in parallel.

10 is a flowchart illustrating an example of an uplink DM-RS transmission method according to the present invention.

Referring to FIG. 10, one example of an uplink DM-RS transmission method according to the present invention is a demodulation reference signal (DM-RS) for each slot in uplink in which a first slot and a second slot exist in one subframe. (S1010) determining a first DM-RS sequence transmitted in a first slot for each antenna participating in uplink transmission, and performing a second DM with respect to at least some of the antennas participating in the uplink transmission. The -RS sequence determines that each antenna multiplies the first DM-RS sequence transmitted in the first slot by -1, or cyclically shifts the first DM-RS sequence transmitted by each antenna in the first slot. (S1020) and transmitting the determined first DM-RS sequence in a first slot, and transmitting the determined second DM-RS sequence in a second slot (S1030).

That is, the uplink DM-RS transmission method according to the present invention described with reference to FIG. 10 will be described as a case where an orthogonal cover code is applied in the time domain over a first slot and a second slot constituting one subframe. Can be. That is, in FIG. 2, the orthogonal cover codes (1, 1) are applied to the antenna 1 and the antenna 2, and the orthogonal cover codes (1, -1) are applied to the antenna 3 and the antenna 4.

Meanwhile, another example of the DM-RS transmission method according to the present invention to which the orthogonal cover code is applied not only in the time domain but also in the frequency domain may be described with reference to FIG. 11.

11 is a flowchart illustrating another example of an uplink DM-RS transmission method according to the present invention.

Referring to FIG. 11, another example of the uplink DM-RS transmission method according to the present invention is similar to the example of the DM-RS transmission method according to the present invention described above. In the existing uplink, a demodulation reference signal (DM-RS) is transmitted for each slot, and the first DM-RS sequences transmitted in the first slot are determined for each antenna participating in the uplink transmission, but the first DM-RS is determined. -RS sequences are determined by the same sequence elements between adjacent subcarriers, or a first DM-RS sequence determination step (S1110) consisting of sequence elements having only a different sign, at least some of the antennas participating in the uplink transmission For the second DM-RS sequence transmitted in the second slot for the multiplied by the first DM-RS sequence transmitted by each antenna in the first slot -1, or the first DM- transmitted by each antenna in the first slot RS Determining that the sequence is cyclically shifted (S1120) and transmitting the determined first DM-RS sequence in a first slot, and transmitting the determined second DM-RS sequence in a second slot (S1130). It can be configured to include.

That is, another example of the uplink DM-RS transmission method according to the present invention illustrated in FIG. 11 is different from an example of the uplink DM-RS transmission method according to the present invention illustrated in FIG. It can be understood that the orthogonal cover code is also applied.

Referring to FIG. 3, the orthogonal cover codes 1, 1, ..., 1, 1 are applied in the frequency domain for the antenna 1 and the antenna 3, while the orthogonal cover codes (for the antenna 2 and the antenna 4 are in the frequency domain). It can be understood that 1, -1, 1, -1, ..., 1, -1) is applied. In addition, orthogonal cover codes (1, 1) are applied to antennas 1 and 2 and the orthogonal cover codes (1, -1) are applied to antennas 3 and 4 in the time domain spanning the first slot and the second slot. It can be described as applied.

The DM-RS transmission methods according to the present invention described with reference to FIGS. 10 and 11 are intended for the case where the DM-RS is transmitted in one DFT-s-OFDM symbol in one slot. In the RS transmission method, the DM-RS may be transmitted in two or more DFT-s-OFDM symbols in one slot.

That is, another example of the uplink DM-RS transmission method proposed by the present invention is to apply the number of OFDM symbols transmitted by the DM-RS in one slot differently according to circumstances.

That is, in some situations, the DM-RS is transmitted in one OFDM (DFT-s-OFDM) symbol in one slot as described in FIG. 1, and in some situations, as described in FIG. 5 or 6. The DM-RS is transmitted in two OFDM symbols within a slot.

In this way, information on how many OFDM symbols the DM-RS is to be transmitted in the slot may be configured so that the base station informs the terminal using downlink control information. Another method may be configured so that the terminal informs the base station of how many OFDM symbols the DM-RS will be transmitted in the slot using the uplink control information.

12 is a flowchart for explaining another example of a DM-RS transmission method according to the present invention.

Referring to FIG. 12, another example of a method of transmitting a DM-RS according to the present invention is a method of transmitting an uplink demodulation reference signal in a terminal, wherein a DFT-s in which a demodulation reference signal is transmitted in one slot is transmitted. -Sharing information on the number of OFDM symbols with the base station (S1210) and constructing a demodulation reference signal transmitted in one slot based on the information on the number of shared DFT-s-OFDM symbols It may be configured to include (S1220).

In this case, information on how many DFT-s-OFDM symbols are transmitted in a slot should be shared between a base station and a terminal, and the terminal receives the demodulation reference signal using uplink control information. The information may be configured to be transmitted to a base station, and the base station may be configured to deliver the information to a terminal transmitting the demodulation reference signal using downlink control information (PDCCH).

However, if the information on how many DFT-s-OFDM symbols in a single slot the DM-RS is to be transmitted is not information that must be updated immediately to reflect the instantaneous channel state between the base station and the terminal, the information on the physical channel The information may be configured to be broadcast to the terminals using information transmitted using RRC signaling or system information (SI) rather than information transmitted.

The DM-RS transmission methods according to the present invention described with reference to FIGS. 10 and 11 assume a case in which a DM-RS is transmitted using one DFT-s-OFDM symbol in one slot, but will be described with reference to FIG. 12. It is also conceivable that a DM-RS is transmitted using two DFT-s-OFDM symbols in one slot by using the conventional transmission method. Further examples of DM-RS transmission methods according to the present invention described below with reference to FIGS. 13 and 14 assume a case in which a DM-RS is transmitted using two DFT-s-OFDM symbols in one slot. will be.

13 is a flowchart for explaining another example of a DM-RS transmission method according to the present invention.

Referring to FIG. 13, another example of a method of transmitting a DM-RS according to the present invention is to copy two DFT-s-OFDM symbols (a first symbol and a second symbol) in one slot present in a subframe. In a method of transmitting a quiet reference signal, determining first DM-RS sequences transmitted in the first symbol for each antenna participating in uplink transmission (S1310), and for at least some of the antennas participating in the uplink transmission The second DM-RS sequence transmitted in the second symbol is -1 multiplied by the first DM-RS sequences transmitted by each antenna in the first symbol, or the first DM-RS transmitted by each antenna in the first symbol. Determining that the RS sequence is cyclically shifted (S1320) and transmitting the determined first DM-RS sequence in the first symbol, and transmitting the determined second DM-RS sequence in the second symbol ( Sphere including S1330) Can be made.

That is, another example of the DM-RS transmission method according to the present invention described with reference to FIG. 13 corresponds to the application of an orthogonal cover code on the time domain as in the DM-RS transmission method according to the present invention described with reference to FIG. do. In the DM-RS transmission method described with reference to FIG. 10, an orthogonal cover code is applied between DM-RS sequences transmitted in a first slot and a second slot. In the DM-RS transmission method described with reference to FIG. It may be described as applying an orthogonal cover code between the DM-RS sequences of the first symbol and the DM-RS sequences of the second symbol transmitted in the slot.

14 is a flowchart for explaining another example of a DM-RS transmission method according to the present invention.

Referring to FIG. 14, another example of the DM-RS transmission method according to the present invention includes a demodulation reference signal in two DFT-s-OFDM symbols (first symbol and second symbol) for each slot present in a subframe. In a method of transmitting an uplink demodulation reference signal, determining first DM-RS sequences transmitted in the first symbol by applying different cyclic shift values for each antenna participating in uplink transmission (S1410); Determining the cyclically shifted sequences of the first DM-RS sequences by a predetermined offset value as the second DM-RS sequences transmitted in the second symbol (S1420), the antenna participating in the uplink transmission At least some of the determined second DM-RS sequences multiplied by −1 are determined as a second DM-RS sequence, and for the remaining parts, the determined second DM-RS sequence is determined. Determining a second DM-RS sequence as it is (S1430) and transmitting the determined first DM-RS sequence in the first symbol, and transmitting the determined second DM-RS sequence in the second symbol ( It may be configured to include (S1440).

In this case, step S1420 may be described through rule 1) described in DM-RS configuration method # 4 according to the present invention. That is, cyclic shift offsets varying according to the cell number i and the slot index k are applied to the sequences applied to configure the DM-RS in the first symbol in one slot.

Next, step S1430 may be described through rule 3) in case of transmission using four antennas and rule 2) in case of transmission using two antennas described in DM-RS configuration method # 4 according to the present invention. have.

On the other hand, in case of transmission using four antennas, the rule described through rule 2) in case of transmission using four antennas in DM-RS configuration method # 4 according to the present invention may be additionally applied to step S1410. .

That is, in the step S1410 of determining the first DM-RS sequence, when the first DM-RS sequence is a first DM-RS sequence of a k (k is an integer) slot, the first DM-RS sequence is determined. If the transmit antenna index m0 is next to the transmit antenna index m0 in the order in which the indexes of the transmit antennas are arranged according to the cyclic shift value applied to the RS sequences, the k + 1th slot, which is the next slot of the kth slot, In the order in which the indexes of the transmitting antennas are arranged according to the cyclic shift values applied to the first DM-RS sequences of the first DM-RS sequence, the first DM-RS sequences may be determined such that there is no transmitting antenna index m1 after the transmitting antenna index m0. have.

Although described with reference to the embodiments above, those skilled in the art will understand that the present invention can be variously modified and changed without departing from the spirit and scope of the invention as set forth in the claims below. Could be.

Claims (9)

In uplink in which a first slot and a second slot exist in one subframe, a demodulation reference signal (DM-RS) is transmitted for each slot.
Determining first DM-RS sequences transmitted in a first slot for each antenna participating in uplink transmission;
The first DM-RS sequence transmitted by each antenna in the first slot is multiplied by −1 for each of the second DM-RS sequences transmitted in the second slot for at least some of the antennas participating in the uplink transmission, or each antenna Determining that the first DM-RS sequence in the first slot has cyclically shifted; And
Transmitting the determined first DM-RS sequence in a first slot and transmitting the determined second DM-RS sequence in a second slot. In uplink in which a first slot and a second slot exist in one subframe, a demodulation reference signal (DM-RS) is transmitted for each slot.
Determine first DM-RS sequences transmitted in a first slot for each antenna participating in uplink transmission, wherein the first DM-RS sequence of at least some of the antennas participating in the uplink transmission has the same sequence element in an adjacent subcarrier pair A first DM-RS sequence determination step, wherein the first DM-RS sequence of the remaining part of the antennas participating in the uplink transmission is composed of sequence elements having different codes only between adjacent subcarriers;
The first DM-RS sequence transmitted by each antenna in the first slot is multiplied by −1 for each of the second DM-RS sequences transmitted in the second slot for at least some of the antennas participating in the uplink transmission, or each antenna Determining that the first DM-RS sequence in the first slot has cyclically shifted; And
Transmitting the determined first DM-RS sequence in a first slot and transmitting the determined second DM-RS sequence in a second slot. A method for transmitting an uplink demodulation reference signal in a terminal,
Sharing information on the number of DFT-s-OFDM symbols on which a demodulation reference signal is transmitted in one slot with a base station; And
And configuring a demodulation reference signal transmitted in one slot based on the information on the number of shared DFT-s-OFDM symbols. The method of claim 3, wherein
In the step of sharing information on the number of DFT-s-OFDM symbols to which the demodulation reference signal is transmitted with a base station, the demodulation reference is transmitted to a base station where the terminal receives the demodulation reference signal using uplink control information. The uplink demodulation reference signal transmission method of claim 1, wherein the information on the number of DFT-s-OFDM symbols on which the signal is transmitted is transmitted. The method of claim 3, wherein
In the step of sharing information on the number of DFT-s-OFDM symbols to which the demodulation reference signal is transmitted with a base station, the base station transmits the demodulation reference signal to the terminal transmitting the demodulation reference signal using downlink control information. The uplink demodulation reference signal transmission method of claim 1, wherein the information on the number of DFT-s-OFDM symbols on which the signal is transmitted is transmitted. In a method of transmitting a demodulation reference signal in two DFT-s-OFDM symbols (a first symbol and a second symbol) in one slot existing in a subframe,
Determining first DM-RS sequences transmitted in the first symbol for each antenna participating in uplink transmission;
The second DM-RS sequence transmitted in the second symbol for at least some of the antennas participating in the uplink transmission is multiplied by −1 to the first DM-RS sequences transmitted by each antenna in the first symbol, or Determining that each antenna has cyclically shifted the first DM-RS sequence transmitted in the first symbol; and
And transmitting the determined first DM-RS sequence in the first symbol and transmitting the determined second DM-RS sequence in the second symbol. A method of transmitting an uplink demodulation reference signal for transmitting a demodulation reference signal in two DFT-s-OFDM symbols (a first symbol and a second symbol) for each slot present in a subframe,
Determining first DM-RS sequences transmitted in the first symbol by applying different cyclic shift values for each antenna participating in uplink transmission;
Constructing second DM-RS sequences of cyclic shifted sequences with respect to the first DM-RS sequences by a predetermined offset value;
At least some of the antennas participating in the uplink transmission are determined as a second DM-RS sequence by multiplying each of the configured second DM-RS sequences by -1, and for the remaining parts, the configured second DM-RS sequence. Determining the RS sequence as the second DM-RS sequence as it is; And
And transmitting the determined first DM-RS sequence in the first symbol and transmitting the determined second DM-RS sequence in the second symbol. The method of claim 7, wherein
In the determining of the first DM-RS sequence, the first DM-RS sequence is a first DM-RS sequence of a k (k is an integer) slot and is applied to the first DM-RS sequences. When the transmit antenna index m0 is next to the transmit antenna index m0 in the order in which the indexes of the transmit antennas are arranged according to the click shift value, the first DM-RS sequence of the k + 1th slot, which is the next slot of the kth slot, is present. The first DM-RS sequence is determined such that the transmission antenna index m1 does not exist after the transmission antenna index m0 in the order in which the indexes of the transmission antennas are arranged according to the cyclic shift value applied to the antennas. Quiet reference signal transmission method. The method of claim 7, wherein
In the configuring of the second DM-RS sequences of the cyclic shifted cyclic shifted by a predetermined offset value with respect to the first DM-RS sequences, the predetermined offset value is the number of the serving cell of the terminal and the first 1. The method of transmitting a reference signal for uplink demodulation, which is determined according to an index value of a slot in which a DM-RS sequence is transmitted.

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