KR20180050223A - Method for transmitting and receiving reference signal - Google Patents

Abstract

The present invention provides a method for transmitting and receiving a reference signal of a transmission device in a wireless communication system for phase error estimation and channel estimation. The transmission device transmits a first reference signal in a first time domain of a resource block included in a transmission period. Also, the transmission device transmits a second reference signal distributed in at least two subcarriers in a second time domain of the resource block including a plurality of symbols following the first time domain.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a reference signal transmission method,

The present invention relates to a reference signal transmission method and a reference signal reception method.

A multicarrier based wireless communication system divides an information signal transmitted through an entire frequency band into a plurality of subcarriers and transmits the delay spread in a time domain and the frequency selective fading in a frequency domain selective fading. Accordingly, high-speed broadband transmission in a wireless environment is possible.

An example of a multi-carrier-based wireless transmission scheme is an orthogonal frequency-division multiplexing (OFDM) transmission scheme. In OFDM, subcarriers can maintain orthogonality in the frequency domain, thereby transmitting information signals without inter-carrier interference (ICI).

In order to perform coherent detection of a received OFDM signal, channel information must be known through channel estimation. At this time, a reference signal (RS) configured with a known sequence of a signal is used for a part of time-frequency resources of the OFDM signal . The reference signal may include a cell-specific RS, a user-specific RS, a demodulation RS, a channel state information reference signal, information-RS, CSI-RS).

Examples of the use of the reference signal in addition to the channel estimation include phase tracking, time / frequency tracking, and radio link monitoring. Among them, phase tracking is used to estimate the phase noise generated in the oscillator inside the transceiver. The oscillator output signal should resonate only at a specific frequency. However, the phenomenon that the oscillation frequency spreads to the adjacent frequency region due to the limitations of the device characteristics and the phase component of the oscillation signal shakes is called phase noise. This phase noise is more likely to occur with a high frequency oscillator, such as a millimeter-wave, and therefore the need for consideration of phase noise is greater in millimeter-wave based communication systems.

Phase noise has two kinds of effects on the received OFDM signal. The first is a common phase error (CPE) that equally rotates the phases of all subcarriers in the OFDM signal. Knowing the phase rotation value, the effect of the CPE can be compensated by rotating it in the opposite direction again. The second is the ICI component that causes interference between subcarriers.

For fast demodulation in OFDM signal demodulation, a channel estimation reference signal can be placed in front of a resource block. In this case, the channel estimation is first performed to obtain the channel information, and the channel information can be used in data demodulation, so that the demodulation delay can be minimized. This reference signal can be used to estimate the phase rotation value for CPE compensation. In this case, the phase error is not estimated for each symbol but the existing estimation value is used. Since the correlation of the phase error values between adjacent OFDM symbols is low, the estimation error becomes large, so that the phase value correction may not be performed properly.

On the other hand, accurate channel estimation can not be guaranteed with only the reference signal placed in front. For example, in a UE with fast mobility, since the channel coherence time is short, precise channel estimation can not be guaranteed only by the reference signal placed in front of it. Therefore, it is necessary to design a reference signal considering phase error estimation and efficient operation of demodulation channel estimation in a fast mobile environment.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and a method for transmitting a reference signal for phase error estimation and channel estimation.

According to an embodiment of the present invention, a method for transmitting a reference signal of a transmission apparatus in a wireless communication system is provided. Wherein the reference signal transmission method comprises: transmitting a first reference signal in a first time domain of a resource block included in a transmission domain; and transmitting a second reference signal in a second time domain of the resource block including a plurality of symbols following the first time domain, And transmitting a second reference signal distributed in at least two subcarriers in an area.

The at least two subcarriers may be spaced apart from each other.

And the second reference signal may be allocated to only one of the subcarriers of the at least two subcarriers.

The plurality of symbols may include a symbol in which the second reference signal is not disposed.

The symbol in which the second reference signal is not arranged may exist between two symbols in which the second reference signal is arranged.

The second reference signal may be alternately arranged in the time direction on the at least two subcarriers.

Wherein the second reference signal is allocated to one subcarrier of the at least two subcarriers in a predetermined number of first symbols and is allocated to another subcarrier among the at least two subcarriers in the predetermined number of second symbols following the first symbol And may be alternately arranged in the time direction on the at least two subcarriers.

There may be a third symbol between the first symbol and the second symbol in which the second reference signal is not arranged.

The predetermined number may be one or two.

The second reference signal may be used for phase tracking and channel estimation.

The transmission interval may be a subframe or a slot.

The first time domain may comprise a symbol following the control domain of the resource block.

The first reference signal may be allocated to a plurality of subcarriers continuous in the first time domain.

According to another embodiment of the present invention, a method for receiving a reference signal of a receiving apparatus in a wireless communication system is provided. The reference signal receiving method includes a first time domain in which a first reference signal is arranged in a plurality of subcarriers and a second reference signal in a dispersed manner in at least two subcarriers in a plurality of symbols, 2 time domain, estimating a channel based on the first reference signal, and estimating a phase error based on the second reference signal.

The step of estimating the channel may include estimating the channel based on the first reference signal and the second reference signal.

The at least two subcarriers may be spaced apart from each other.

The second reference signal may be alternately arranged in the time direction on the at least two subcarriers.

Wherein the second reference signal is allocated to one subcarrier of the at least two subcarriers in a predetermined number of first symbols and is allocated to another subcarrier among the at least two subcarriers in the predetermined number of second symbols following the first symbol And may be alternately arranged in the time direction on the at least two subcarriers.

There may be a third symbol between the first symbol and the second symbol in which the second reference signal is not arranged.

According to another embodiment of the present invention, a transmission apparatus is provided in a wireless communication system. The transmission apparatus includes a processor and a transmitter. Wherein the processor is configured to allocate a first reference signal in a first time domain of a resource block included in a transmission domain and to allocate at least two of the resource blocks in a second time domain of the resource block including a plurality of symbols following the first time domain The second reference signals are dispersed and arranged in subcarriers. The transmitter transmits the resource block.

According to one embodiment of the present invention, compared with the case where the phase addition reference signal is continuously arranged on a specific subcarrier, the performance of the channel estimation accuracy is improved in the demodulation channel estimation for supporting high-speed mobility while maintaining the same phase tracking performance .

1 is a diagram schematically illustrating a wireless communication system according to an embodiment of the present invention.
2 is a diagram showing a reference signal allocation method in a conventional wireless communication system.
3 is a schematic flowchart of a reference signal transmission method according to an embodiment of the present invention.
4 to 11 are diagrams illustrating a method of arranging additional reference signals according to various embodiments of the present invention.
12 is a schematic flowchart of a reference signal receiving method according to an embodiment of the present invention.
13 to 22 are diagrams illustrating a method of arranging additional reference signals according to various embodiments of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, a terminal may be referred to as a user equipment (UE), a mobile station (MS), a mobile terminal (MT), an advanced mobile station (AMS) a high reliability mobile station (HR-MS), a subscriber station (SS), a portable subscriber station (PSS), an access terminal (AT), a machine type communication device MTC device or the like and may include all or some of the functions of UE, MS, MT, AMS, HR-MS, SS, PSS,

Also, a base station (BS) includes a Node B, an evolved Node B, an eNB, a gNB, an advanced base station (ABS), a high reliability base station (BS), an access point (AP), a radio access station (RAS), a base transceiver station (BTS), a mobile multihop relay (MMR) a relay station (RS), a relay node (RN) serving as a base station, an advanced relay station (ARS) serving as a base station, a high reliability relay station , HR-RS, a femto BS, a home Node B, a HNB, a pico BS, a macro BS, a micro base station (BS) the BS may be referred to as an NB, eNB, gNB, ABS, AP, RAS, BTS, MMR-BS, RS, RN, ARS, HR- There's also an included feature.

The expressions described in the singular may be interpreted as singular or plural unless an explicit expression such as " a " or " a " is used.

1 is a diagram schematically illustrating a wireless communication system according to an embodiment of the present invention.

Referring to FIG. 1, a wireless communication system includes a plurality of base stations 110 and a plurality of terminals 120.

The base station 110 transmits the reference signal and the downlink data. The terminal 120 receives a reference signal and estimates a channel or a phase error. Similarly, the terminal 120 also transmits the reference signal and the uplink data. The base station 120 receives the reference signal and estimates the channel or phase error.

The base station 110 includes a processor 111 and transceivers 112 and 113 and the transceiver includes a transmitter 112 and a receiver 113. The processor 111, the transmitter 112, and the receiver 113 may each be formed of physical hardware. The transmitter 112 and the receiver 113 may be formed of one hardware (e.g., chip). The processor 111, the transmitter 112, and the receiver 113 may all be formed of one hardware (e.g., chip).

The processor 111 implements an upper layer 111a and a physical layer 111b and executes commands necessary for the operation of the base station 110 and controls operations of the transmitter 112 and the receiver 113 . The transmitter 112 transmits the signal received from the physical layer 111b to the terminal 120 through the antenna and the receiver 113 receives the signal from the terminal 120 through the antenna and transmits the signal to the physical layer 111b do. Similarly, the terminal 120 includes a processor 121 and transceivers 122 and 123, and the transceiver includes a transmitter 122 and a receiver 123. The processor 121, the transmitter 122, and the receiver 123 may each be formed of physical hardware. The transmitter 122 and the receiver 123 may be formed of one piece of hardware (e.g., a chip). The processor 121, the transmitter 122, and the receiver 123 may all be formed of one hardware (e.g., chip).

The processor 121 implements the upper layer 121a and the physical layer 121b and executes commands necessary for the operation of the terminal 120 and controls the operations of the transmitter 112 and the receiver 113 . The transmitter 122 transmits the signal received from the physical layer 121b to the base station 110 via the antenna and the receiver 123 receives the signal from the base station 110 through the antenna and transmits the signal to the physical layer 121b do. The transmitter 122 and the receiver 123 may exchange signals with other terminals 120. [

In some embodiments, the wireless communication system may be applied to various wireless communication networks. For example, the wireless communication system may be applied to current wireless access technology (RAT) based wireless communication networks or 5G and later wireless communication networks. 3GPP is developing a new RAT-based 5G standard that satisfies the IMT-2020 requirements. This new RAT is called NR (New Radio).

In some embodiments, a wireless communication system is a multi-carrier system that delivers information signals over a plurality of subcarriers, including OFDM, windowed-OFDM with filtered, filtered-OFDM with filtered or filtered- bank multi-carrier, FBMC, and generalized frequency-division multiplexing (GFDM). Also, the wireless communication system may include a guard period in the time domain. Examples of the guard interval include a cyclic prefix, a cyclic postfix, or a null guard period. .

2 is a diagram illustrating a reference signal allocation method in a wireless communication system according to an embodiment of the present invention.

Referring to FIG. 2, a reference signal 220 is allocated to a symbol following a control region 210 in a resource block, and an additional reference signal 230 is continuously arranged in a time domain on one subcarrier after the reference signal 220 do.

Since the correlation of the phase error values between adjacent OFDM symbols is low, if the existing estimation value is used without estimating the phase error for each symbol, the estimation error becomes large and the phase value correction may not be performed properly. Therefore, by disposing the additional reference signal 230 continuously in the time domain as shown in FIG. 2, the additional reference signal 230 can be used for phase error estimation.

On the other hand, since accurate channel estimation can not be guaranteed only with the reference signal 220 arranged in front of the terminal having fast mobility, for example, the additional reference signal 230 can be used for channel estimation for data demodulation other than phase error estimation have. In this case, since the additional reference signal 230 is allocated only to one subcarrier, the channel estimation performance may not be good. In particular, the additional reference signal 230 may not accurately estimate a time-selective fading channel occurring in a UE environment having fast mobility.

A reference signal transmission and allocation method capable of improving the channel estimation performance will now be described with reference to FIGS. 3 to 11. FIG. In some embodiments, the method of transmitting a reference signal may be applied to a downlink, an uplink, or a sidelink of a wireless communication system.

3 is a schematic flowchart of a reference signal transmission method according to an embodiment of the present invention.

Referring to FIG. 3, the transmission apparatus of the wireless communication system places a reference signal in front of a resource block of a transmission duration (S310). In the future, this reference signal is referred to as a front-loaded reference signal. In some embodiments, the reference signal is located immediately after the control region in the transmission interval, and the data region may be disposed immediately after the reference signal. In some embodiments, the transmission interval may be a slot or a subframe. The resource block may include a plurality of symbols in a time domain and may include a plurality of subcarriers in a frequency domain.

The transmitting apparatus places an additional reference signal after the reference signal disposed in the data area (S320). At this time, the transmitting apparatus does not arrange additional reference signals continuously in one subcarrier but distributes the additional reference signals in a frequency domain from a plurality of symbols in the data area. In some embodiments, the transmitting apparatus may place additional reference signals alternately in time direction on two or more spaced apart subcarriers. In one embodiment, among the plurality of symbols in the data area, there may be a symbol in which no additional reference signal is placed. In some embodiments, when an additional reference signal is arranged alternating between two or more subcarriers, an additional reference signal may be placed in each subcarrier on only one subcarrier.

Next, the transmitting apparatus transmits a resource block (S330). The resource block may include control information allocated to the control area and data allocated to the data area in addition to the reference signal.

In the following, various embodiments for arranging additional reference signals with reference to Figs. 4 to 11 will be described.

4 to 11 are diagrams illustrating a method of arranging additional reference signals according to various embodiments of the present invention.

Referring to FIG. 4, in one embodiment, the additional reference signal may be arranged alternately to two subcarriers of the resource block. For example, in a transmission apparatus, a subcarrier having an index j (hereinafter referred to as a " subcarrier j ") in a symbol following the reference signal (for example, The additional reference signal is arranged in the subcarrier j and k in the same pattern with respect to the next symbol, and the additional reference signal is arranged in the subcarrier j and k in the symbol (i + 1). That is, the transmitting apparatus allocates an additional reference signal to the subcarrier j in the symbol (i + 2n) and the additional reference signal in the subcarrier k in the symbol (i + (2n + 1) (Where n is an integer equal to or greater than zero).

In some embodiments, the two carriers on which the additional reference signal is placed may be spaced apart from each other. That is, the difference between j and k may be greater than one.

Even when the additional reference signal is distributed over a plurality of subcarriers, the common phase error (CPE) is the same for all subcarriers, as in the embodiment of the present invention, so that the phase addition reference signal is continuously arranged in a specific subcarrier The phase tracking performance can be kept the same as in the case of FIG. On the other hand, since the additional reference signals are dispersed in the frequency domain and the inter-frequency spacing that can be estimated becomes narrow, the performance of channel estimation accuracy can be improved in demodulation channel estimation for supporting high-speed mobility.

Although FIG. 4 shows an example in which the additional reference signals are alternately arranged on the subcarriers 3 and 9, the index of the subcarrier on which the additional reference signal is placed is not limited thereto.

Referring to FIG. 5, in an alternative embodiment, the additional reference signal may be placed alternately to at least three subcarriers of the resource block. For example, in the transmission apparatus, an additional reference signal is allocated to the subcarrier j in the symbol (e.g., symbol i) following the reference signal, and an additional reference signal is allocated to the subcarrier k in the symbol (i + 1) , And the symbol (i + 2), the additional reference signal is allocated to the subcarrier l and the additional reference signal is alternately arranged in the two subcarriers j, k and l in the same pattern for the next symbol. That is, the transmitting apparatus allocates an additional reference signal to the subcarrier j in the symbol (i + 3n), places an additional reference signal in the subcarrier k in the symbol (i + (3n + 1) ), An additional reference signal can be arranged in such a manner that an additional reference signal is arranged on the subcarrier l (n is an integer equal to or larger than 0).

In some embodiments, the three or more carriers on which the additional reference signal is placed may be spaced apart from each other. That is, the difference between j and k, the difference between k and l, and the difference between j and l may be greater than one.

According to the embodiment described with reference to FIG. 5, since the interval between frequencies that can be estimated is narrower than the embodiment described with reference to FIG. 4, the channel estimation accuracy can be further improved.

5, the additional reference signal is alternately arranged on the subcarriers 3, 7 and 10. However, the index of the subcarrier on which the additional reference signal is placed is not limited thereto.

6 and 7, in another embodiment, when the additional reference signals are dispersed in the frequency domain, two or more additional reference signals may be disposed adjacent to each other.

As shown in FIG. 6, when the additional reference signal is alternately arranged in two subcarriers of the resource block, two or more additional reference signals may be adjacent to each other. For example, in the case of the symbol (i + 2) and the symbol (i + 3), the transmission apparatus allocates an additional reference signal to the subcarrier j in the symbol i and the symbol And an additional reference signal can be alternately arranged in two subcarriers j and k in the same pattern for the next symbol. That is, the transmitting apparatus allocates the additional reference signal to the subcarrier j in the symbol (i + 4n) and the symbol (i + (4n + 1) ), An additional reference signal can be arranged by arranging an additional reference signal in the subcarrier k (where n is an integer equal to or greater than 0).

As shown in FIG. 7, when the additional reference signal is alternately arranged to three or more subcarriers of the resource block, two or more additional reference signals may be adjacent to each other. For example, in the case of the symbol (i + 2) and the symbol (i + 3), the transmission apparatus allocates an additional reference signal to the subcarrier j in the symbol i and the symbol (I + 4) and (i + 5), an additional reference signal is allocated to the subcarrier 1, and an additional reference signal is allocated to the two subcarriers j, k and l in the same pattern for the next symbol. Can be arranged alternately. (I + 6n + 2) and symbol (i + (6n + 3)) are allocated to the subcarrier j in the symbol i + 6n and the symbol i + ), An additional reference signal can be placed in the subcarrier k and an additional reference signal can be placed in the subcarrier l in the symbol (i + (6n + 4)) and the symbol (i + (6n + 5) (Where n is an integer equal to or greater than zero).

Although FIGS. 6 and 7 show the case where two additional reference signals are adjacent to each other, three or more additional reference signals may be adjacent to each other.

6 shows an example in which the additional reference signal is alternately arranged in the subcarriers 3 and 9, and in FIG. 7, the additional reference signal is alternately arranged in the subcarriers 3, 7 and 10. However, Is not limited to this.

Referring to Figs. 8, 9, 10 and 11, in another embodiment, when additional reference signals are scattered and arranged in the frequency domain, symbols not including additional reference signals may be arranged.

As shown in Fig. 8, when an additional reference signal is alternately arranged in two subcarriers of a resource block, a symbol not including an additional reference signal can be arranged. For example, the transmitting apparatus allocates the additional reference signal to the subcarrier j in the symbol i following the reference signal disposed in front of the reference signal, does not allocate the additional reference signal in the symbol (i + 1) it is possible to arrange the additional reference signals in the two subcarriers j and k alternately in the same pattern with respect to the next symbol without arranging the additional reference signal in the symbol (i + 3). That is, the transmitting apparatus allocates an additional reference signal to the subcarrier j in the symbol (i + 4n), places an additional reference signal in the subcarrier k in the symbol i + (4n + 2) ) And the symbol (i + (4n + 3)), the additional reference signal can be arranged in such a manner that no additional reference signal is arranged (n is an integer equal to or more than 0).

As shown in FIG. 9, when an additional reference signal is arranged alternately with three or more subcarriers of a resource block, symbols that do not include an additional reference signal can be arranged. For example, the transmitting apparatus allocates the additional reference signal to the subcarrier j in the symbol i following the reference signal disposed in front of the reference signal, does not allocate the additional reference signal in the symbol (i + 1) the additional reference signal is arranged in the symbol (i + 3), the additional reference signal is not arranged in the symbol (i + 3), the additional reference signal is arranged in the subcarrier l in the symbol It is possible to arrange the additional reference signals alternately in the two subcarriers j, k and l in the same pattern with respect to the next symbol without arranging the signals. That is, the transmitting apparatus allocates the additional reference signal to the subcarrier j in the symbol (i + 6n), allocates the additional reference signal in the subcarrier k in the symbol (i + (6n + 2) , An additional reference signal is arranged in the subcarrier l and a method in which no additional reference signal is arranged in the symbol (i + (6n + 1)), the symbol (i + (4n + 3) (Where n is an integer greater than or equal to zero).

As shown in FIG. 10, when the additional reference signals are alternately arranged in two subcarriers of the resource block, two or more additional reference signals are adjacent to each other, and symbols that do not include additional reference signals can be arranged. For example, the transmitting apparatus allocates an additional reference signal to the subcarrier j in the symbol i and the symbol (i + 1) following the reference signal disposed in front of it, and does not allocate the additional reference signal in the symbol (i + (i + 3) and (i + 4), the additional reference signal is allocated to the subcarrier k and the additional reference signal is not allocated to the symbol (i + 5) The additional reference signals can be alternately arranged. (I + 6n + 3) and symbol (i + (6n + 4)) are allocated to the subcarrier j in the symbol (i + 6n) , An additional reference signal can be arranged in the subcarrier k and the additional reference signal can be arranged in such a manner that no additional reference signal is arranged in the symbol (i + (6n + 2)) and the symbol (i + (6n + 5) Where n is an integer greater than or equal to zero).

As shown in FIG. 11, when the additional reference signal is alternately arranged to at least three subcarriers of the resource block, two or more additional reference signals may be adjacent to each other and a symbol not including an additional reference signal may be disposed. For example, in the transmitting apparatus, an additional reference signal is allocated to the subcarrier j in the symbol i and symbol (i + 1) following the precedence reference signal, and an additional reference signal is allocated in the symbol (i + 2) (I + 4) and symbol (i + 5) do not arrange additional reference signals in the subcarriers k and symbols (i + 6) and (I + 10) and (i + 11) may not allocate an additional reference signal to the symbol (i + 8) and the symbol (i + 9).

In this way, the reference signal overhead can be reduced by arranging the symbols not including the additional reference signal in the resource block.

8 and 10 show an example in which the additional reference signals are alternately arranged on the subcarriers 3 and 9, and in FIGS. 9 and 11, the additional reference signals are alternately arranged on the subcarriers 3, 7 and 10, The index of the subcarrier on which the reference signal is placed is not limited to this.

In FIGS. 4 to 11, the resource block includes 12 subcarriers in the frequency domain and 14 symbols in the time domain. However, the size of the resource block is not limited thereto. For example, a resource block may include 12 subcarriers in the frequency domain and 7 symbols in the time domain.

In some embodiments, in Figures 4 to 11, the number of additional reference signals allocated to each subcarrier (i.e., the number of symbols in which the additional reference signal is located) may be the same.

In some embodiments, a method for placing an additional reference signal in a resource block may be determined in a base station or a network. For example, any of the additional reference signal placement methods described with reference to Figures 3 to 11 in a base station or network may be selected. In one embodiment, the base station may receive channel or terminal movement related information from the terminal or may estimate it using the uplink signal. In this case, in the case where the channel state is good or the terminal movement speed is slow, a symbol not including the additional reference signal may be allocated to the resource block in order to reduce the overhead of the additional reference signal.

In some embodiments, the determined additional reference signal allocation method may be delivered to the terminal via the control message in the control domain of the resource block or may be delivered to the terminal via a radio resource control (RRC) message.

In some embodiments, the method of arranging additional reference signals may be varied. In one embodiment, the modification of the method of arranging additional reference signals may be dynamic or semi-static.

In some embodiments, the subcarrier interval in the resource block may be an exponential gain (2 ⁿ * 15 kHz) of 15 kHz times 2. For example, the subcarrier spacing may be selected from a set of {15 kHz, 30 kHz, 60 kHz, 120 kHz, 240 kHz, 480 kHz}.

In some embodiments, when using a cyclic prefix (CP) as the guard interval, a normal CP and an extended CP longer than the normal CP may be used as the CP length.

12 is a schematic flowchart of a reference signal receiving method according to an embodiment of the present invention.

Referring to FIG. 12, the receiving apparatus of the wireless communication system receives a resource block of a transmission interval (S1210). A reference signal is arranged in front of the resource block, and an additional reference signal is arranged after the reference signal arranged in front of the data area of the resource block, as described with reference to FIG. 4 to FIG.

The receiving apparatus estimates the channel based on the reference signal (S1220). The estimated channel information can be used in data demodulation. The receiving apparatus also estimates a phase error based on the additional reference signal (S1230). The phase error can be used for phase value correction. In some embodiments, the receiving device may use an additional reference signal in addition to the reference signal when estimating the channel.

Next, with reference to FIG. 13 to FIG. 22, a method of transmitting and arranging reference signals in a wireless communication system according to another embodiment of the present invention will be described.

13 to 22 are diagrams illustrating a method of arranging additional reference signals according to various embodiments of the present invention.

Referring to FIG. 13 to FIG. 22, when an additional reference signal is allocated to one subcarrier as shown in FIG. 2, there may exist a symbol (i.e., a resource element) that does not include an additional reference signal.

13, in one embodiment, when placing an additional reference signal in one subcarrier of a resource block, there may be one symbol in which no additional reference signal is placed between two symbols in which an additional reference signal is placed . For example, when the transmitting apparatus allocates the additional reference signal to the subcarrier j, the additional reference signal is arranged in the symbol i following the reference signal disposed before the reference signal, and the additional reference signal is not arranged in the symbol (i + 1) An additional reference signal can be placed in the subcarrier j in the same pattern for the next symbol. That is, the transmitting apparatus can arrange additional reference signals in such a manner that an additional reference signal is allocated to the subcarrier j in the symbol (i + 2n) and no additional reference signal is allocated in the symbol (i + (2n + 1)) Where n is an integer greater than or equal to zero).

In some embodiments, a transmitting device may simultaneously transmit a plurality of resource blocks.

In one embodiment, an additional reference signal may be placed at the same symbol position in a plurality of resource blocks as shown in FIG. For example, in a plurality of resource blocks, an additional reference signal is allocated to the subcarrier j in the symbol (i + 2n) and no additional reference signal is allocated in the symbol (i + (2n + 1)).

In another embodiment, as shown in FIG. 15, there may exist resource blocks in which a position of a symbol in which a supplementary reference signal is allocated in a plurality of resource blocks is different. For example, in one resource block, an additional reference signal may be placed in subcarrier j in symbol (i + 2n) and no additional reference signal may be placed in symbol i + (2n + 1) (i + 2n + 1), an additional reference signal may be allocated to subcarrier j and no additional reference signal may be allocated to symbol (i + 2n).

13-15 illustrate an embodiment in which there is one symbol in which no additional reference signal is placed between two symbols in which additional reference signals are arranged, There may be more than one symbol that is not placed. In the following, an embodiment in which there are two symbols in which no additional reference signal is disposed between two symbols in which an additional reference signal is arranged will be described with reference to FIG. 16 to FIG.

As shown in FIG. 16, in another embodiment, there may be two symbols between which the additional reference signal is placed and no additional reference signal is placed. For example, when a transmitting apparatus allocates an additional reference signal to a subcarrier j, an additional reference signal is arranged in a symbol i following the reference signal disposed before the reference signal, and an additional reference signal is allocated in a symbol (i + 1) and a symbol It is possible to arrange the additional reference signal in the sub-carrier j in the same pattern for the next symbol without arranging the reference signal. That is, the transmitting apparatus allocates the additional reference signal to the subcarrier j in the symbol (i + 3n) and does not allocate the additional reference signal in the symbol (i + (3n + 1)) and the symbol (Where n is an integer greater than or equal to zero).

16 shows the case where there are two symbols in which no additional reference signal is arranged between two symbols in which additional reference signals are arranged, but three symbols in which additional reference signals are not arranged between two symbols in which additional reference signals are arranged The above symbols may exist.

In some embodiments, a transmitting device may simultaneously transmit a plurality of resource blocks.

In one embodiment, an additional reference signal may be placed at the same symbol position in a plurality of resource blocks as shown in Fig. For example, in a plurality of resource blocks, an additional reference signal is allocated to subcarrier j in symbol (i + 3n), and an additional reference signal is allocated in symbol i + (3n + 1) and symbol i + It may not be disposed.

In another embodiment, as shown in FIG. 18 and FIG. 19, there may exist resource blocks in which a position of a symbol in which a supplementary reference signal is allocated in a plurality of resource blocks is different. For example, as shown in FIG. 18, in one resource block, an additional reference signal is allocated to subcarrier j in symbol i + 3n and symbols i + (3n + 1) and i + (3n + (I + 3n + 1)) in the other resource block and the additional reference signal is not allocated in the subcarrier j in the symbol (i + (3n + 1) The additional reference signal may not be disposed. 19, in a resource block, an additional reference signal is allocated to a subcarrier j in a symbol (i + 3n) and a symbol (i + (3n + 1) An additional reference signal may not be allocated and an additional reference signal is allocated to the subcarrier j in the symbol (i + (3n + 2)) in the other resource block and the additional reference signal is allocated in the symbol (i + 3n + Additional reference signals may not be placed. As another example, in one resource block, an additional reference signal is allocated to subcarrier j in symbol (i + 3n) and an additional reference signal is allocated in symbol (i + (3n + 1)) and symbol (i + (I + 3n + 1) in the other resource block and the additional reference signal is allocated in the subcarrier j and in the symbol (i + 3n) and the symbol (i + (3n + 2) In the other resource block, an additional reference signal is allocated to the subcarrier j in the symbol (i + (3n + 2)) and an additional reference signal is allocated in the symbol (i + 3n) and the symbol (i + .

20 to 22, in another embodiment, when an additional reference signal is placed on one subcarrier so that a symbol does not include an additional reference signal, two or more additional reference signals may be arranged adjacent to each other .

As shown in FIG. 20, when an additional reference signal is placed in one subcarrier of a resource block, an additional reference signal is placed in two adjacent symbols, and no additional reference signal is placed between two symbols in which an additional reference signal is placed More than one symbol may be present. For example, there may be two symbols between which the additional reference signal is placed and no additional reference signal is placed. In this case, when the transmitting apparatus allocates the additional reference signal to the subcarrier j, the additional reference signal is arranged in the symbol i and the symbol (i + 1) following the precedent reference signal, and the symbol (i + i + 3), it is possible to arrange additional reference signals in the sub-carrier j in the same pattern for the next symbol without allocating additional reference signals. That is, the transmitting apparatus allocates the additional reference signal to the subcarrier j in the symbol (i + 4n) and the symbol (i + (4n + 1) ), Additional reference signals can be placed in a manner that no additional reference signal is placed (where n is an integer equal to or greater than zero).

Although FIG. 20 illustrates the case where an additional reference signal is placed in two adjacent symbols, an additional reference signal may be placed in three or more adjacent symbols. Although FIG. 20 shows a case where no additional reference signal is placed in two adjacent symbols, an additional reference signal may not be disposed in one symbol or three or more adjacent symbols.

In some embodiments, a transmitting device may simultaneously transmit a plurality of resource blocks.

In one embodiment, an additional reference signal may be placed at the same symbol position in a plurality of resource blocks as shown in FIG. For example, in the plurality of resource blocks, an additional reference signal is arranged in the symbol (i + 4n) and the symbol (i + (4n + 1) ), The additional reference signal may not be disposed.

In another embodiment, as shown in FIG. 22, there may exist resource blocks in which a position of a symbol in which a supplementary reference signal is allocated in a plurality of resource blocks is different. For example, in one resource block, an additional reference signal is allocated to the subcarrier j in the symbol (i + 4n) and the symbol (i + (4n + 1) The additional reference signal may not be allocated in the subcarrier j and the additional reference signal is allocated to the subcarrier j in the symbol i + (4n + 2) and the symbol i + (4n + 3) i + 4n) and the symbol (i + (4n + 1)).

As described with reference to FIGS. 13 to 22, the reference signal overhead can be reduced by arranging the symbols not including the additional reference signal in the resource block.

13 to 22 show an example in which the additional reference signal is allocated to the subcarrier 3, the index of the subcarrier on which the additional reference signal is placed is not limited thereto.

13 to 22 show an example in which the resource block includes 12 subcarriers in the frequency domain and 14 symbols in the time domain, but the size of the resource block is not limited thereto. For example, a resource block may include 12 subcarriers in the frequency domain and 7 symbols in the time domain.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

Claims (20)

A method of transmitting a reference signal of a transmission apparatus in a wireless communication system,
Transmitting a first reference signal in a first time domain of a resource block included in a transmission interval, and
Transmitting a second reference signal distributed in at least two subcarriers in a second time domain of the resource block including a plurality of symbols following the first time domain;
And transmitting the reference signal. The method of claim 1,
Wherein the at least two subcarriers are spaced apart from each other. The method of claim 1,
And the second reference signal is allocated only to one of the subcarriers of the at least two subcarriers in the symbol in which the second reference signal is arranged. 4. The method of claim 3,
Wherein the plurality of symbols include a symbol in which the second reference signal is not disposed. 5. The method of claim 4,
Wherein a symbol in which the second reference signal is not present is present between two symbols in which the second reference signal is disposed. The method of claim 1,
Wherein the second reference signal is arranged alternately in the time direction on the at least two subcarriers. The method of claim 6,
Wherein the second reference signal is allocated to one subcarrier of the at least two subcarriers in a predetermined number of first symbols and is allocated to another subcarrier among the at least two subcarriers in the predetermined number of second symbols following the first symbol Wherein the at least two subcarriers are arranged alternately in the time direction. 8. The method of claim 7,
And a third symbol in which the second reference signal is not disposed is present between the first symbol and the second symbol. 8. The method of claim 7,
Wherein the predetermined number is one or two. 8. The method of claim 7,
And the second reference signal is used for phase tracking and channel estimation. The method of claim 1,
Wherein the transmission interval is a subframe or a slot. The method of claim 1,
Wherein the first time domain comprises a symbol following the control domain of the resource block. The method of claim 12,
Wherein the first reference signal is allocated to a plurality of subcarriers continuous in the first time domain. A method for receiving a reference signal of a receiving apparatus in a wireless communication system,
A second time domain in which a first reference signal is arranged in a plurality of subcarriers and a second reference signal is distributed in at least two subcarriers in a plurality of symbols, Receiving a block,
Estimating a channel based on the first reference signal, and
Estimating a phase error based on the second reference signal
And transmitting the reference signal. The method of claim 14,
Wherein estimating the channel comprises estimating the channel based on the first reference signal and the second reference signal. The method of claim 14,
Wherein the at least two subcarriers are spaced apart from each other. The method of claim 14,
And the second reference signal is arranged alternately in the time direction on the at least two subcarriers. The method of claim 17,
Wherein the second reference signal is allocated to one subcarrier of the at least two subcarriers in a predetermined number of first symbols and is allocated to another subcarrier among the at least two subcarriers in the predetermined number of second symbols following the first symbol Wherein the at least two subcarriers are arranged alternately in the time direction in the form of a subcarrier. The method of claim 18,
And a third symbol in which the second reference signal is not disposed is present between the first symbol and the second symbol. A transmission device in a wireless communication system,
A second reference signal is allocated to a first time domain of a resource block included in a transmission interval and a second reference signal is allocated to at least two subcarriers in a second time domain of the resource block including a plurality of symbols following the first time domain, A processor for distributing and arranging reference signals, and
The transmitter for transmitting the resource block
.

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