KR101430050B1 - Method of transmitting uplink demodulation reference signal - Google Patents

Abstract

A reference signal transmission method for uplink demodulation is disclosed. In order to distinguish uplink demodulation reference signals transmitted on a per antenna basis when MIMO is applied to uplink transmission, an orthogonal cover code is applied to a time domain or a time domain and a frequency domain to a reference signal sequence for uplink demodulation . In addition, it is also possible to apply a different cyclic shift to the reference signal for uplink demodulation for each antenna, or to apply a different cyclic shift for each slot. Also, it may be configured to transmit a reference signal for uplink demodulation in two or more DFT-s-OFDM symbols in one slot in order to cope with a high moving speed. Therefore, using the reference signal transmission method for uplink demodulation according to the present invention, it is possible to maintain the orthogonality between DM-RS sequences transmitted for each antenna when MIMO is applied in uplink transmission, In LTE-advanced, which is required to support higher moving speeds, uplink demodulation performance can be maintained.

Description

[0001] The present invention relates to a method of transmitting a reference signal for uplink demodulation,

The present invention relates to a method of transmitting a reference signal for uplink demodulation, and more particularly, to a method of transmitting a reference signal for uplink demodulation considering multi-input / output applicable to 3GPP LTE-advanced.

Currently, a standard created by the 3rd Generation Partnership Project (3GPP), a standardization body of international radio transmission technology, and IEEE 802.16, consider a case where a base station has a maximum of 4 transmit antennas (i.e., downlink transmission). However, there will be a demand for a higher data rate in the future, and accordingly, multiple input multiple output (MIMO) must be performed in the uplink. In order to perform multiple I / O in the uplink, it is necessary to modify the reference signal (RS) design method.

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

That is, FIG. 1 illustrates a physical uplink shared channel (PUSCH) demodulation for an uplink proposed in 3GPP LTE Release 8 TS36.211 v8.6.0 "Evolved Universal Terrestrial Radio Access (E-UTRA) The design structure of DM-RS (Demodulation RS) is explained.

FIG. 1 illustrates a case where one slot is composed of seven symbols (DFT-s-OFDM symbol) (when a normal CP is used), and one subframe (subframe; 100 is composed of two slots 101 and 102, and the 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 0.5 ms.

(DM-RS) symbols in the time domain within a slot when N _SC uplink frequency domain resources are allocated to a given user. The length of the reference signal sequence for each transmission antenna is N _SC .

In this case, the DM-RS for the first slot and the DM-RS for the second slot in one subframe may be transmitted using subcarriers of the same position depending on the presence or absence of frequency slot hopping, / RTI > may be transmitted using the subcarriers of the location.

In the above description and the current uplink DM-RS transmission structure illustrated in FIG. 1, since DM-RS transmission in the case of introducing multiple input / output is not considered in the uplink of LTE, multiple input / In this case, it is necessary to transmit the DM-RS orthogonal to each layer. In addition, a later version of LTE, LTE-advanced, is defined to support a higher mobile speed (e.g., 350 Km per hour requirement) than LTE, resulting in a higher Doppler spread environment It is satisfactory with the current DM-RS transmission structure and it is difficult to expect the performance. This is because the fading channel can be rapidly changed within one slot period (0.5 ms) at a high moving speed. Therefore, it is also necessary to improve the DM-RS transmission method considering such a high moving speed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of transmitting a reference signal for uplink demodulation capable of supporting a high moving speed, considering that multiple input and output are applied to an uplink.

According to an aspect of the present invention, there is provided a method of transmitting a reference signal for uplink demodulation according to an aspect of the present invention, including: receiving a demodulation reference signal for each slot in an uplink in which a first slot and a second slot exist in one subframe, A method of transmitting a signal (DM-RS), comprising: determining first DM-RS sequences to be transmitted in a first slot for each of antennas participating in uplink transmission; A first DM-RS sequence transmitted by each antenna in the first slot is multiplied by -1, or a first DM-RS sequence transmitted by each antenna in the first slot is multiplied by -1, And determining the first DM-RS sequence to be cyclic-shifted, and transmitting the determined first DM-RS sequence in a first slot and the determined second DM-RS sequence in a second slot, Lt; / RTI >

According to another aspect of the present invention, there is provided a method for transmitting a reference signal for uplink demodulation in an uplink in which a first slot and a second slot exist in one subframe, A method of transmitting a reference signal (DM-RS), comprising: determining first DM-RS sequences to be transmitted in a first slot for each of antennas participating in uplink transmission, The DM-RS sequence is composed 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 is composed of sequence elements with different signs between adjacent subcarriers A second DM-RS sequence determining unit for determining a second DM-RS sequence for transmitting at least a part of the antennas participating in the uplink transmission in a second slot, RS of the first DM-RS sequence transmitted by the antenna in the first slot or -1 by cyclically shifting the first DM-RS sequence transmitted by the antenna in the first slot by -1, 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, there is provided a method for transmitting a reference signal for uplink demodulation in a mobile station, the method comprising: A step of sharing information on the number of DFT-s-OFDM symbols to which a reference signal is transmitted with a base station, and a demodulation reference transmitted in one slot based on the information on the number of the shared DFT- And configuring the signal.

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

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

According to another aspect of the present invention, there is provided a method of transmitting a reference signal for uplink demodulation, the method comprising the steps of: receiving, in a slot existing in a subframe, two DFT-s- And determining a first DM-RS sequence to be transmitted in the first symbol for each of the antennas participating in the uplink transmission, and transmitting the demodulation reference signal to the antennas participating in the uplink transmission, The first DM-RS sequences transmitted from the first symbol by each antenna are multiplied by -1 by a first DM-RS sequence transmitting at least a part of the second DM-RS sequence to the second symbol, Wherein the determined first DM-RS sequence is cyclic-shifted and the determined first DM-RS sequence is transmitted in the first symbol, and wherein the determined second DM-RS sequence is cyclic- And transmitting it from the ball.

According to another aspect of the present invention, there is provided a method of transmitting a reference signal for uplink demodulation, comprising the steps of: receiving two DFT-s-OFDM symbols (first symbol and second symbol A first DM-RS sequence for transmitting a reference signal for uplink demodulation, which transmits a reference signal for demodulation, to a first symbol by applying a different cyclic shift value to each antenna participating in uplink transmission, Configuring the first DM-RS sequences with cyclic-shifted sequences by a predetermined offset value into second DM-RS sequences, determining at least some of the antennas participating in the uplink transmission RS sequence is determined as a second DM-RS sequence by multiplying each of the second DM-RS sequences constructed above by -1, and the remaining part is determined as a second DM- RS sequence as a second DM-RS sequence, and the determined first DM-RS sequence is transmitted in the first symbol, and the determined second DM-RS sequence is transmitted in the second symbol Step < / RTI >

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

Here, in the step of constructing the second DM-RS sequences cyclically shifted by a predetermined offset value with respect to the first DM-RS sequences, the predetermined offset value may be the number of the serving cell of the terminal And the index value of the slot through which the first DM-RS sequence is transmitted.

When the uplink DM-RS transmission method according to the present invention as described above is used, orthogonality between DM-RS sequences transmitted for each antenna can be maintained when MIMO is applied in uplink transmission.

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

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

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail.

It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations 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 to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the relevant art and are to be interpreted in an ideal or overly formal sense unless explicitly defined in the present application Do not.

A "terminal" used in the present application 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), a wireless device, a wireless communication device, a wireless transmit / receive unit (WTRU), a mobile node, a mobile, or other terminology. Various embodiments of the terminal may be used in various applications such as cellular telephones, smart phones with wireless communication capabilities, personal digital assistants (PDAs) with wireless communication capabilities, wireless modems, portable computers with wireless communication capabilities, Devices, gaming devices with wireless communication capabilities, music storage and playback appliances with wireless communication capabilities, Internet appliances capable of 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.

A 'base station' used in the present application generally refers to a fixed point in communication with a terminal and includes a base station, a Node-B, an eNode-B, a BTS a transceiver system, an access point, and the like.

Also, the demodulation reference signal and the control signal transmission method for the uplink MIMO described in the present invention can be applied not only to a conventional base station but also to a relay node.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In order to facilitate the understanding of the present invention, the same reference numerals are used for the same constituent elements in the drawings and redundant explanations for the same constituent elements are 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, an uplink DM-RS configuration method according to the present invention will be described first, and an uplink DM-RS transmission method according to the present invention using them will be described below.

Hereinafter, various uplink DM-RS configuration methods according to the present invention will be described separately for convenience of explanation. However, in the uplink DM-RS transmission method according to the present invention, each of the DM- But also the case where they are used in combination with each other.

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

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

FIG. 2 is a conceptual diagram illustrating a case in which a DM-RS is transmitted in one DFT-s-OFDM symbol in one slot, as in the uplink DM-RS configuration of the conventional LTE, as illustrated in FIG.

1, one method of configuring an uplink DM-RS for uplink demodulation according to the present invention is a method of forming uplink DM-RSs for a first slot 101 in a subframe 100 in a time domain, (OCC: Orthogonal Cover Code) is used for the DM-RS 112 for the first slot 111 and the second slot 102. That is, orthogonal cover codes are applied in the time domain.

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

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

2, in the second slot 102, the transmission antennas 1 and 2 transmit the same sequence elements 211 and 212, which are transmitted in the first slot 101, in the uplink DM-RS configuration of the present invention, (I.e., 211 and 212 are the same sequences as 201 and 202, respectively). Transmit antennas 3 and 4 multiply -1 by the sequence transmitted in the first slot 101, and transmit in the second slot 102 (I.e., 213 and 214 are sequences obtained by multiplying 203 and 204 sequences by -1, respectively).

에 대해서,

(정수)만큼 사이클릭 쉬프트시킨 시퀀스는

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

about,

(Integer) cyclic shift sequence

As shown in Fig.

Meanwhile, FIG. 2 illustrates a case where four antennas are used in uplink transmission, but an uplink DM-RS transmission method may be configured in a similar manner when there are two antennas participating in transmission.

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

By applying the method using the above-described orthogonal cover code (OCC), the orthogonality of a sequence for each antenna transmitted on a slot basis can be further strengthened, so that the uplink DM-RS can be configured to be suitable for multiple input / . That is, since the demultiplexing of the DM-RS signal is increased for each antenna at the receiving end, demodulation performance of the received data can be enhanced.

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

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

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

Referring to FIG. 3, a sequence of length N _SC / 2 is used in each antenna. That is, the sequence (C _1,0 , C _1,1 , C _1,2 , ..., C _{1, Nsc / 2-1} ) is used for the transmission antenna 1. Also, the same sequence element is used between two neighboring subcarriers, or a sequence one different from the other is used.

For example, in the case of the transmission antennas 1 and 3 in the first slot, the same sequence element _C0,0 or _C3,0 is used (301) for the subcarriers 0 and 1, and the same sequence element C _{1 , 1,} or C _3,1 is used (302). On the other hand, in the case of the transmit antennas 2 and 4, the sequence element C _2,0 or C _4,0 is used for the subcarrier 0 (303), but for the subcarrier 1, the sequence element C _2,0 or -C _4,0 is used (304) (i.e., OCC is applied in the frequency domain).

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

에 대해서,

(정수)만큼 사이클릭 쉬프트시킨 시퀀스는

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

about,

(Integer) cyclic shift sequence

As shown in Fig.

Meanwhile, FIG. 3 illustrates a case where four antennas are used in uplink transmission, but an uplink DM-RS transmission method may be configured in a similar manner when two antennas participating in transmission are used.

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

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

On the other hand, in the second slot, transmission antennas 1 and 2 transmit the same sequence element as that transmitted in the first slot, and transmission antennas 3 and 4 transmit a sequence element multiplied by -1 in the transmission in the first slot.

As described above, by using the orthogonal cover code (OCC) for the time domain and the frequency domain, the orthogonality of the antenna-specific sequence transmitted on a slot-by-slot basis is further enhanced, and the uplink DM- The transmission method can be configured.

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

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

In a later version of LTE, LTE-advanced, which is currently under standardization, is defined to support higher mobile speeds (for example, 350 Km per hour according to requirements) in comparison to LTE, resulting in a higher Doppler spread ) Environment, it is satisfactory for the current DM-RS transmission structure, and it is difficult to expect the performance. This is because the fading channel can be rapidly changed within one slot period (0.5 ms) at a high moving speed. For this, it may be necessary to transmit the DM-RS through a plurality of symbols rather than one OFDM symbol (DFT-s-OFDM symbol) within one slot.

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

Referring to FIG. 6, a reference signal transmission method for uplink demodulation in which one slot is composed of six OFDM symbols (DFT-s-OFDM symbol) (when an extended CP is applied) The reference signal for uplink demodulation is transmitted from the second OFDM symbol 611, 613 and the fifth OFDM symbol 612, 614 in the slot 601 or 602. [

When an 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, or an uplink DM-RS May be configured to be transmitted.

FIG. 7 is a conceptual diagram for explaining a concept of applying orthogonal cover codes in another example of a method of constructing a reference signal for uplink demodulation according to the present invention.

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

In this case, each transmit antenna uses a sequence of length N _SC , and transmit antennas 3 and 4 use a sequence element obtained by multiplying a sequence element transmitted from the first DM-RS in one slot by -1, .

In other words, the application of the orthogonal cover code described in FIG. 7 is described in the application of the orthogonal cover code described in FIG. 2 to the DM-RS sequence of the first slot and the second slot, 1 < / RTI > DM-RS sequence and the second DM-RS sequence.

Also, a sequence used in the second slot for each transmission antenna may use a cyclic-shifted sequence of a sequence used in the first slot, and FIG. 7 illustrates a case in which four antennas are used in the uplink transmission However, the uplink DM-RS transmission method may be configured in a similar manner in the case of two antennas participating in transmission.

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

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

. 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. A sequence obtained by cyclic shifting this basic sequence by a (integer) is

. ≪ / RTI > The demodulation reference signal sequence for demodulation for each transmit antenna is a cyclic shift value

. That is, the DM-RS sequence for the transmit antenna m (m = 1, 2, ...)

. At this time, the actual sequence is

As shown in Fig.

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

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

1) When there are 4 transmit 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 of the i-th cell and the k-th slot, a cyclic shift

. That is, the transmission antenna m is a cyclic shift

. Here, the rules 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, a cyclic shift offset

.

[Equation 1]

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

Depends on the cell number i and the slot index k.

For example, referring to FIG. 8, if the cyclic shift value used for each of the four antennas is [0, 6, 3, 9] for the first DM-RS in the slot, 8 (the case where 8 is applied as an example of the cyclic shift offset in FIG. 8 is exemplified, but the cyclic shift offset actually applied may be different) is applied so that the cyclic shift value of [8, 2, 11, 5] It is exemplified as being applied to each antenna. At this time, in the case of the antenna 2 and the antenna 4, since the offset 8 is applied and the shift value is cyclic, the cyclic shifts 2 and 5 are applied to the sequence of the second DM-RS.

Rule 2) When m1 arrives after an arbitrary transmit antenna index m0 in the slot index k when the transmit antenna index is aligned according to the cyclic shift value, in the slot index k + 1, m1 does not follow the transmit antenna index m0 Applies the click shift value.

For example, if the transmit antenna index is aligned according to the cyclic shift value at the slot index k, (1, 3, 2, 4). Then, when the transmission antenna index is aligned according to the cyclic shift value in the slot index k + 1, 3 is not allocated to the transmission antenna 1, 2 is not allocated after the transmission antenna 3, 4 And no transmission antenna 4 is provided.

One such example is to apply a cyclic shift value for each antenna of slot index k + 1 to (1, 4, 2, 3). The reason for constructing the cyclic shift value at the slot index k + 1 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, since the difference in the cyclic shift values between the antenna 1 and the antenna 3 is small in the slot index k, the antenna 3 has a large influence on the channel estimation of the transmission antenna 1. If the cyclic shift value of the antenna 3 follows the antenna 1 even at the slot index k + 1, the antenna 3 affects the channel estimation for the antenna 1 even at the slot index k + 1. Therefore, Rule 2 is applied to randomize the inter-antenna interference at the time of channel estimation for each slot.

Rule 3) The two transmit antennas use orthogonal cover code 1 (OCC1) and the other two transmit antennas use orthogonal cover code 2 (OCC2). The indexes of two transmission antennas using orthogonal cover codes are 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.

Referring to FIG. 8, in slot k, transmission antennas 1 and 2 use orthogonal cover code 1 (OCC1), and in the next slot, transmission antennas 1 and 3 use orthogonal cover code 2 (OCC2). As described above, the combination of the transmission antennas constituting the orthogonal cover codes 1 and 2 is 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 for determining the cyclic shift value and the orthogonal cover code satisfies all three of the above rules. Rules to be satisfied.

2) When there are two transmit antennas

를 사용한다고 가정한다. 즉, 송신 안테나 m은 사이클릭 쉬프트

를 사용한다고 가정한다. For the first DM-RS of the i-th cell and the k-th slot, two transmission antennas are used for the cyclic shift

. That is, the transmission antenna m is a cyclic shift

.

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

Hereinafter, with reference to FIG. 9 in parallel, rules for using cyclic shift and orthogonal cover codes when there are two transmit antennas will be described.

를 사용하는 것이다.
Rule 1) For the second DM-RS of the same slot, a cyclic shift offset

.

&Quot; (2) "

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

Depends on the cell number i and the slot index k.

Rule 2) One transmission antenna uses orthogonal cover code 1 (OCC1) and the other one transmission antenna uses orthogonal cover code 2 (OCC2). The index of the transmission 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) equally for OCC1 and OCC2.

Referring to FIG. 9, in the slot k, the transmission antenna 1 uses the orthogonal cover code 1 (OCC1), and in the next slot, the transmission antenna 2 uses the orthogonal cover code 1 (OCC1). As described above, the combination of the transmission antennas constituting the orthogonal cover codes 1 and 2 is 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 for determining the cyclic shift value and the orthogonal cover code is determined so as to satisfy both of the above two rules, To satisfy as many rules as possible.

The uplink DM-RS transmission method according to the present invention

According to the uplink DM-RS configuration method according to the present invention, the UE can transmit uplink DM-RS to the BS.

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 DM-RS configuration method described above with reference to FIG. 2 to FIG. 9, And Fig. 9, respectively.

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

10, in an uplink DM-RS transmission method according to the present invention, in an uplink where first and second slots exist in one subframe, a demodulation reference signal DM-RS (S1010) for determining a first DM-RS sequence to be transmitted in a first slot for each of the antennas participating in uplink transmission, -RS sequence is determined by multiplying the first DM-RS sequence transmitted by each antenna in the first slot by -1 or determining that each antenna cyclic-shifts the first DM-RS sequence transmitted 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, which is described with reference to FIG. 10, will be described as a case where an orthogonal cover code is applied on the time domain over the first slot and the second slot constituting one subframe . 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.

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

11 is a flowchart for explaining another example of the 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 includes a first slot and a second slot in one subframe, as in the DM-RS transmission method according to the present invention described above (DM-RS) for each slot in an existing uplink, the first DM-RS sequences to be transmitted in a first slot are determined for each antenna participating in uplink transmission, and the first DM The RS-RS sequences include a first DM-RS sequence determination step (S1110) in which adjacent subcarriers are determined to have the same sequence elements or are made up of sequence elements having different signs, at least one of the antennas participating in the uplink transmission The first DM-RS sequence transmitted by the antenna in the first slot is multiplied by -1 or the first DM-RS sequence transmitted by the antenna in the first slot is multiplied by -1, RS (S1120) determining that the sequence is cyclic-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 (S1130) And the like.

In other words, unlike the uplink DM-RS transmission method according to the present invention illustrated in FIG. 10, another example of the uplink DM-RS transmission method according to the present invention illustrated in FIG. 11 is not limited to the time domain, It can be understood that an orthogonal cover code is also applied.

3, orthogonal cover codes (1, 1, ..., 1, 1) are applied to the antenna 1 and the antenna 3 in the frequency domain while orthogonal cover codes 1, -1, 1, -1, ..., 1, -1). An orthogonal cover code (1,1) is applied to the antenna 1 and the antenna 2 in the time domain extending over the first slot and the second slot, and an orthogonal cover code (1, -1) is applied to the antenna 3 and the antenna 4 It can be explained as applied.

The DM-RS transmission methods according to the present invention described with reference to FIGs. 10 and 11 are directed to a case where a DM-RS is transmitted in one DFT-s-OFDM symbol in one slot. However, RS transmission method, the DM-RS may be configured to 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 to which the DM-RS is transmitted in one slot differently depending on the situation.

That is, under certain circumstances, a DM-RS is transmitted in one OFDM (DFT-s-OFDM) symbol in one slot as described in FIG. 1, and in some situations, Lt; RTI ID = 0.0 > OFDM < / RTI >

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

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

12, a method of transmitting a reference signal for uplink demodulation in a mobile station (D-RS) according to another embodiment of the present invention is a method for transmitting a reference signal for demodulation in a slot, (S1210) sharing information on the number of OFDM symbols with a base station, and configuring a demodulation reference signal transmitted in one slot based on the information on the number of shared DFT-s-OFDM symbols (S1220).

At this time, information on how many DFT-s-OFDM symbols are to be transmitted within one slot between the Node B and the UE should be shared. When the UE receives the demodulation reference signal using uplink control information The base station may be configured to transmit the information to the base station, and the base station may be configured to transmit the information to the terminal that transmits the demodulation reference signal using the downlink control information (PDCCH, etc.).

However, if information on how many DM-RSs are to be transmitted in a DFT-s-OFDM symbol in one slot is not information that should be immediately updated by reflecting the instantaneous channel state between the BS and the MS, Information transmitted using RRC signaling or the like, or information broadcasted to terminals using system information (SI) or the like.

The DM-RS transmission methods according to the present invention described with reference to FIGS. 10 and 11 assume that a DM-RS is transmitted using one DFT-s-OFDM symbol in one slot, And the DM-RS may be transmitted using two DFT-s-OFDM symbols in one slot using a transmission method that has been used. Hereinafter, another example of the DM-RS transmission methods according to the present invention described with reference to FIG. 13 and FIG. 14 assumes that 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 the DM-RS transmission method according to the present invention.

Referring to FIG. 13, another example of the DM-RS transmission method according to the present invention is a method for transmitting a DFT-s-OFDM symbol (first symbol and second symbol) in one slot existing in a subframe. A method for transmitting a quiet reference signal, the method comprising: determining first DM-RS sequences to be transmitted in the first symbol for each antenna participating in uplink transmission in step S1310; The second DM-RS sequence transmitted to the second symbol may be calculated by multiplying the first DM-RS sequences transmitted by the first symbol by -1, or by multiplying the first DM- (S1320) determining that the RS sequence is cyclic-shifted and transmitting the determined first DM-RS sequence in the first symbol, and transmitting the determined second DM-RS sequence in the second symbol S1330) .

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

FIG. 14 is a flowchart for explaining another example of the 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 for two DFT-s-OFDM symbols (first symbol and second symbol) (S1410) of determining first DM-RS sequences to be transmitted in the first symbol by applying different cyclic shift values to the antennas participating in uplink transmission, (S1420) determining, as the second DM-RS sequences, cyclic-shifted sequences for the first DM-RS sequences by a predetermined offset value in the second symbol at step S1420, RS sequence by multiplying each determined second DM-RS sequence by -1 for at least a portion of the second DM-RS sequence, and for the remaining part, determining the second DM-RS sequence determined (S1430) of determining the first DM-RS sequence as it is, and transmitting the determined first DM-RS sequence in the first symbol and the determined second DM-RS sequence in the second symbol S1440).

At this time, the step S1420 can be explained through the rule 1 described in the DM-RS configuration method # 4 according to the present invention. That is, a cyclic shift offset that depends on the cell number i and the slot index k is applied to the sequences applied to construct the DM-RS in the first symbol in one slot.

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

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

That is, when determining that the first DM-RS sequence is a first DM-RS sequence of k (k is an integer) th slot in step S1410, the first DM- If the transmission antenna index m1 is present following the transmission antenna index m0 in the order in which the indexes of the transmission antennas are aligned according to the cyclic shift values applied to the RS sequences, The first DM-RS sequence can be determined such that the transmit antenna index m0 does not exist after the transmit antenna index m0 in the order of the indexes of the transmit antennas according to the cyclic shift values applied to the first DM-RS sequences of the first DM- have.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims. It will be possible.

Claims (9)

A method for transmitting a demodulation reference signal (DM-RS) for each slot in an uplink in which a first slot and a second slot exist in one subframe,
Determining first DM-RS sequences to be transmitted in a first slot for each antenna participating in uplink transmission;
A first DM-RS sequence transmitted by each antenna in a first slot is multiplied by -1, a second DM-RS sequence transmitted in a second slot for at least a part of the antennas participating in the uplink transmission, Determining a cyclic shift of a first DM-RS sequence transmitted in a first slot; 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 a demodulation reference signal (DM-RS) for each slot in an uplink in which a first slot and a second slot exist in one subframe,
The first DM-RS sequences transmitted in the first slot for each of the antennas participating in the uplink transmission are determined, and the first DM-RS sequences of at least some antennas participating in the uplink transmission include the same sequence elements A first DM-RS sequence determination step of determining a first DM-RS sequence of remaining ones of the antennas participating in the uplink transmission, the first DM-RS sequence being composed of sequence elements having different signs from adjacent subcarriers;
A first DM-RS sequence transmitted by each antenna in a first slot is multiplied by -1, a second DM-RS sequence transmitted in a second slot for at least a part of the antennas participating in the uplink transmission, Determining a cyclic shift of a first DM-RS sequence transmitted in a first slot; 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 a reference signal for uplink demodulation in a terminal,
Sharing information on the number of DFT-s-OFDM symbols to which a demodulation reference signal is transmitted in one slot with a base station; And
And constructing a demodulation reference signal transmitted in one slot based on information on the number of shared DFT-s-OFDM symbols. The method of claim 3,
The step of sharing the information on the number of DFT-s-OFDM symbols to which the demodulation reference signal is transmitted with the base station is performed by the base station receiving the demodulation reference signal using the uplink control information, S-OFDM symbols to which the signals are transmitted. The method of claim 1, The method of claim 3,
The step of sharing the information on the number of DFT-s-OFDM symbols to which the demodulation reference signal is transmitted with the base station is performed by the base station transmitting the demodulation reference signal to the terminal that transmits the demodulation reference signal using the downlink control information. S-OFDM symbols to which the signals are transmitted. The method of claim 1, A method for transmitting a demodulation reference signal to two DFT-s-OFDM symbols (first symbol and second symbol) in one slot existing in a subframe,
Determining first DM-RS sequences to be transmitted in the first symbol for each antenna participating in uplink transmission;
A first DM-RS sequence transmitted from a first symbol by each antenna is multiplied by -1, a second DM-RS sequence transmitted to the second symbol for at least a part of the antennas participating in the uplink transmission, Determining that each antenna cyclically shifts a first DM-RS sequence transmitted in a 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 for transmitting an uplink demodulation reference signal for transmitting a demodulation reference signal to two DFT-s-OFDM symbols (first symbol and second symbol) for each slot existing in a subframe,
Determining first DM-RS sequences to be transmitted in the first symbol by applying different cyclic shift values for respective antennas participating in uplink transmission;
Constructing second DM-RS sequences by cyclic-shifting the first DM-RS sequences by a predetermined offset value;
The sequence of the second DM-RS sequence multiplied by -1 is determined as a second DM-RS sequence for at least a part of the antennas participating in the uplink transmission, and the remaining part of the second DM- RS sequence as a second DM-RS sequence; 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. 8. The method of claim 7,
Wherein the first DM-RS sequence is a first DM-RS sequence of k (k is an integer) th slot, and the first DM-RS sequence is a first DM- The first DM-RS sequence of the (k + 1) -th slot, which is the next slot of the k-th slot, when the transmission antenna index m0 is present following the transmission antenna index m0 in the order of arranging the indexes of the transmission antennas according to the click- RS sequence is determined so that a transmission antenna index m1 does not exist after a transmission antenna index m0 in an order in which the indexes of the transmission antennas are aligned according to a cyclic shift value applied to the uplink sub- A method of transmitting a quiet reference signal. 8. The method of claim 7,
In the step of constructing the second DM-RS sequences cyclically shifted by a predetermined offset value with respect to the first DM-RS sequences as the second DM-RS sequences, 1 DM-RS sequence is determined according to the index value of the slot through which the DM-RS sequence is transmitted.

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