KR102442041B1 - Method for non-orthogonal transmission in communication system and apparatus for the same - Google Patents

Abstract

A method and apparatus for non-orthogonal transmission in a communication system are disclosed. A non-orthogonal transmission method performed by a terminal in a communication system comprises the steps of: generating data based on a signature used to identify the terminal from among a plurality of terminals belonging to the communication system, the data and a DM-RS generating an uplink signal, and transmitting the uplink signal to a base station without an uplink grant. Accordingly, the performance of the communication system may be improved.

Description

METHOD FOR NON-ORTHOGONAL TRANSMISSION IN COMMUNICATION SYSTEM AND APPARATUS FOR THE SAME

The present invention relates to a non-orthogonal transmission technique in a communication system, and more particularly, to a technique for transmitting an uplink signal in a non-orthogonal transmission procedure.

A communication system includes a core network (eg, mobility management entity (MME), serving gateway (SGW), packet data network (PDN) gateway), etc.), base station (eg, macro) base station , a small base station, a relay, etc.), a terminal, and the like. Communication between the base station and the terminal is a variety of radio access technology (RAT) (eg, 4G communication technology, 5G communication technology, wireless broadband (WiBro) technology, wireless local area network (WLAN) technology, WPAN (wireless personal area network) technology etc.) can be performed.

When the uplink data exists in the terminal, the terminal may transmit a message requesting scheduling of the uplink data to the base station. The base station may receive a message requesting scheduling of uplink data from the terminal, and may transmit an uplink grant (eg, scheduling information) to the terminal in response to the message. When the uplink grant is received from the base station, the terminal may transmit uplink data to the base station using the resources allocated by the base station.

When autonomous transmission (eg, non-orthogonal transmission) is supported in a communication system, the UE may transmit uplink data to the base station without an uplink grant. For example, the terminal may select a resource from a preset resource pool, and may transmit uplink data to the base station using the selected resource. Here, the preset resource pool may be shared by the base station and a plurality of terminals. Since the terminal cannot know the resources used by other terminals, the resources selected by the terminal in the preset resource pool may overlap with the resources used by other terminals. In this case, a plurality of terminals may transmit uplink data using the same resource (eg, a non-orthogonal resource), and thus a transmission collision may occur. Therefore, a method for resolving the collision problem of uplink data in the autonomous transmission procedure will be required.

In addition, a demodulation reference signal (DM-RS) may be used for estimating an uplink channel in an autonomous transmission procedure (eg, a non-orthogonal transmission procedure). For example, the terminal may transmit an uplink signal including uplink data and DM-RS to the base station. The base station may estimate an uplink channel based on the DM-RS received from the terminal, and may perform a decoding operation on uplink data based on the estimated uplink channel. However, when the same DM-RS is used by a plurality of terminals, the base station may not be able to obtain uplink data of each of the plurality of terminals because the base station cannot estimate an uplink channel of each of the plurality of terminals. Therefore, a method for solving the DM-RS collision problem in the autonomous transmission procedure will be required.

An object of the present invention for solving the above problems is to provide a method and apparatus for transmitting and receiving an uplink signal based on a signature of a terminal in a communication system.

A non-orthogonal transmission method performed by a terminal in a communication system according to a first embodiment of the present invention for achieving the above object is based on a signature used to identify the terminal from among a plurality of terminals belonging to the communication system. generating data, generating an uplink signal including the data and a DM-RS, and transmitting the uplink signal to a base station without an uplink grant.

Here, the signature may be a C-RNTI configured by the base station.

Here, the data may be interleaved using a sequence set based on the C-RNTI, and the sequence may be a value obtained by dividing the C-RNTI into quarters.

Here, the data may be scrambled using a sequence set based on the C-RNTI.

Here, the sequence of the DM-RS may be determined based on the C-RNTI within a range determined based on the length of the ZC sequence and the number of DM-RS symbols spread in the subframe.

Here, the sequence of the DM-RS may be a sequence indicated by a randomly selected row in a Latin square matrix, and the Latin square matrix may include a plurality of different sequences.

Here, the plurality of terminals may be classified into at least two groups, and the uplink signal may further include a group indicator indicating a group to which the terminal belongs.

Here, the group indicator may be located at a preset interval in consecutive subframes used for transmission of the uplink signal.

Here, the group indicator may be located in the first symbol of at least one subframe among consecutive subframes used for transmission of the uplink signal.

In order to achieve the above object, a method of operating a base station in a communication system according to a second embodiment of the present invention includes receiving uplink signals from a plurality of terminals through a non-orthogonal resource without an uplink grant, the plurality of terminals identifying each of the DM-RSs included in the uplink signals based on each of the signatures, estimating an uplink channel of each of the plurality of terminals using each of the identified DM-RSs, and and acquiring data of each of the plurality of terminals from the uplink signals based on the estimated uplink channel.

Here, the signature may be a C-RNTI set by the base station, and the data may be obtained by performing a descrambling operation using a sequence set based on the C-RNTI.

Here, the signature may be a C-RNTI configured by the base station, the data may be obtained by performing a deinterleaving operation using a sequence set based on the C-RNTI, and the sequence may be determined by the C-RNTI. It may be a value divided into 4 equal parts.

Here, the plurality of terminals may be classified into at least two groups, and the uplink signals may further include a group indicator indicating a group to which each of the plurality of terminals belongs.

Here, the group indicator may be located at a preset interval in consecutive subframes used for transmission of each of the uplink signals.

Here, the group indicator may be located in a first symbol of at least one subframe among consecutive subframes used for transmission of each of the uplink signals.

In order to achieve the above object, a terminal supporting non-orthogonal transmission in a communication system according to a third embodiment of the present invention includes a processor and a memory in which at least one command executed by the processor is stored, and the at least one command generates data based on a signature used to identify the terminal from among a plurality of terminals belonging to the communication system, generates an uplink signal including the data and a DM-RS, and transmits the uplink signal It is executed to transmit to the base station without an uplink grant.

Here, the signature may be a C-RNTI configured by the base station, the data may be interleaved using a sequence set based on the C-RNTI, and the sequence may be a value obtained by dividing the C-RNTI into quarters. have.

Here, the signature may be a C-RNTI configured by the base station, and the data may be scrambled using a sequence configured based on the C-RNTI.

Here, the signature may be a C-RNTI configured by the base station, and the DM-RS sequence is within a range determined based on the length of the ZC sequence and the number of DM-RS symbols spread in the subframe. may be determined based on the C-RNTI.

Here, the plurality of terminals may be classified into at least two groups, and the uplink signal may further include a group indicator indicating a group to which the terminal belongs.

According to the present invention, the terminal can generate uplink data and a demodulation reference signal (DM-RS) based on a signature, and can transmit an uplink signal including the uplink data and the DM-RS to the base station. have. The base station may receive uplink signals (eg, uplink data, DM-RS) from a plurality of terminals, and transmit the DM-RS of each of the plurality of terminals based on the signature of each of the plurality of terminals. can be distinguished, and the uplink channel of each of the plurality of terminals can be estimated based on the differentiated DM-RS.

In addition, the base station can distinguish the uplink data of each of the plurality of terminals based on the signature of each of the plurality of terminals, and decoding ( decoding) operation can be performed. Accordingly, the problem of collision of uplink signals (eg, uplink data, DM-RS) between a plurality of terminals in an autonomous transmission procedure (eg, non-orthogonal transmission procedure) can be resolved, and the performance of the communication system is improved can be improved

1 is a conceptual diagram illustrating a first embodiment of a communication system.
2 is a block diagram showing a first embodiment of a communication node constituting a communication system.
3 is a flowchart illustrating a first embodiment of a communication method based on an autonomous transmission method.
4 is a block diagram illustrating a first embodiment of a terminal supporting a single-carrier scheme.
5 is a block diagram illustrating a first embodiment of a terminal supporting a multi-carrier scheme.
6 is a conceptual diagram illustrating a first embodiment of a 4×4 Latin square matrix.
7 is a conceptual diagram illustrating a first embodiment of a 5×5 Latin square matrix.
8 is a conceptual diagram illustrating a position of a DM-RS symbol in a subframe.
9 is a conceptual diagram illustrating a first embodiment of a sequence number of a DM-RS in a subframe.
10 is a conceptual diagram illustrating a second embodiment of a sequence number of a DM-RS in a subframe.
11 is a conceptual diagram illustrating a scenario in which DM-RS collision occurs.
12 is a conceptual diagram illustrating a first embodiment of uplink transmission based on a group indicator.
13 is a conceptual diagram illustrating a position of a group indicator in a subframe.

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

Terms such as first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. and/or includes a combination of a plurality of related listed items or any of a plurality of related listed items.

When a component is referred to as being “connected” or “connected” to another component, it may be directly connected or connected to the other component, but it is understood that other components may exist in between. it should be On the other hand, when it is said that a certain element is "directly connected" or "directly connected" to another element, it should be understood that the other element does not exist in the middle.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It is to be understood that this does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, 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 a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. In describing the present invention, in order to facilitate the overall understanding, the same reference numerals are used for the same components in the drawings, and duplicate descriptions of the same components are omitted.

1 is a conceptual diagram illustrating a first embodiment of a communication system.

Referring to FIG. 1 , the communication system 100 may include a plurality of communication nodes 110 , 121 , 122 , 123 , 124 , and 125 . In addition, the communication system 100 is a core network (core network) (eg, S-GW (serving-gateway), P-GW (packet data network (PDN)-gateway), MME (mobility management entity)) may include more. A plurality of communication nodes are 4G communication (eg, long term evolution (LTE), LTE-A (advanced)) defined in 3GPP (3rd generation partnership project) standard, 5G communication (eg, NR (new radio)) communication), etc.

For example, the plurality of communication nodes may include a code division multiple access (CDMA)-based communication protocol, a wideband CDMA (WCDMA)-based communication protocol, a time division multiple access (TDMA)-based communication protocol, and a frequency division multiple access (FDMA) based communication protocol. based communication protocol, OFDM (orthogonal frequency division multiplexing) based communication protocol, Filtered OFDM based communication protocol, OFDMA (orthogonal frequency division multiple access) based communication protocol, SC (single carrier)-FDMA based communication protocol, NOMA (Non-orthogonal Multiple Access), GFDM (generalized frequency division multiplexing) based communication protocol, FBMC (filter bank multi-carrier) based communication protocol, UFMC (universal filtered multi-carrier) based communication protocol, SDMA (Space Division) Multiple Access)-based communication protocols may be supported.

Meanwhile, each of the plurality of communication nodes may have the following structure.

2 is a block diagram showing a first embodiment of a communication node constituting a communication system.

Referring to FIG. 2 , the communication node 200 may include at least one processor 210 , a memory 220 , and a transceiver 230 connected to a network to perform communication. The communication node 200 may further include an input interface device 240 , an output interface device 250 , a storage device 260 , and the like. Also, the communication node 200 may further include at least one antenna. Each of the components included in the communication node 200 may be connected by a bus 270 to communicate with each other.

The processor 210 may execute a program command stored in at least one of the memory 220 and the storage device 260 . The processor 210 may mean a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to embodiments of the present invention are performed. Each of the memory 220 and the storage device 260 may be configured as at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 220 may be configured as at least one of a read only memory (ROM) and a random access memory (RAM).

Referring back to FIG. 1 , in the communication system 100 , the base station 110 may form a macro cell or a small cell, and may be connected to the core network through an ideal backhaul or a non-ideal backhaul. can The base station 110 may transmit a signal received from the core network to the corresponding terminals 121, 122, 123, 124, and 125, and transmit the signal received from the corresponding terminals 121, 122, 123, 124, and 125 to the core network. can be sent to The plurality of terminals 121 , 122 , 123 , 124 , and 125 may belong to cell coverage of the base station 110 . The plurality of terminals 121 , 122 , 123 , 124 , and 125 may be connected to the base station 110 by performing a connection establishment procedure with the base station 110 . The plurality of terminals 121 , 122 , 123 , 124 , and 125 may communicate with the base station 110 after being connected to the base station 110 .

In addition, the base station 110 MIMO transmission (eg, single user (SU)-MIMO, multi user (MU)-MIMO, massive MIMO, etc.), CoMP (coordinated multipoint) transmission, CA (carrier aggregation) It may support transmission, transmission in an unlicensed band, device to device communication (D2D) (or Proximity Services (ProSe)), and the like. Here, each of the plurality of terminals 121 , 122 , 123 , 124 , and 125 may perform an operation corresponding to the base station 110 , an operation supported by the base station 110 , and the like.

Here, the base station 110 is a NodeB (NodeB), an advanced NodeB (evolved NodeB), a base transceiver station (BTS), a radio remote head (RRH), a transmission reception point (TRP), a radio unit (RU), an RSU ( road side unit), a wireless transceiver (radio transceiver), an access point (access point), may be referred to as an access node (node). Each of the plurality of terminals 121, 122, 123, 124, and 125 is a user equipment (UE), an access terminal, a mobile terminal, a station, a subscriber station, and a mobile It may be referred to as a mobile station, a portable subscriber station, a node, a device, an on-broad unit (OBU), and the like.

Meanwhile, when autonomous transmission (eg, non-orthogonal transmission) is supported in the communication system, the UE may transmit an uplink signal to the base station without an uplink grant. For example, the terminal may select a resource from a preset resource pool, and may transmit an uplink signal including uplink data and a reference signal to the base station using the selected resource. The reference signal may be used for channel estimation between the base station and the terminal. For example, the reference signal may be a demodulation reference signal (DM-RS).

The preset resource pool may be shared by the base station and a plurality of terminals. Since the terminal cannot know the resources used by other terminals, the resources selected by the terminal in the preset resource pool may overlap with the resources used by other terminals. In this case, a plurality of terminals may transmit an uplink signal using the same resource, and thus a transmission collision may occur. In addition, the same DM-RS may be used in a plurality of terminals, and in this case, the base station may not be able to estimate the channel of each of the plurality of terminals using the DM-RS, and thus may not decode uplink data. can

Next, embodiments for improving reception performance in a communication system supporting autonomous transmission (eg, non-orthogonal transmission) (eg, data generated based on a signature of a terminal and DM-RS A method of transmitting/receiving an uplink signal including a method of generating a DM-RS based on a signature of a terminal, a method of transmitting/receiving based on a group indicator, etc.) will be described. In the embodiments described below, even when a method (eg, transmission or reception of a signal) performed in a first communication node among communication nodes is described, a corresponding second communication node is performed in the first communication node A method corresponding to the method used may be performed (eg, reception or transmission of a signal). That is, when the operation of the terminal is described, the corresponding base station may perform the operation corresponding to the operation of the terminal. Conversely, when the operation of the base station is described, the corresponding terminal may perform the operation corresponding to the operation of the base station.

3 is a flowchart illustrating a first embodiment of a communication method based on an autonomous transmission method.

Referring to FIG. 3 , the communication system may include a base station, a terminal, and the like, and may be configured the same as or similar to the communication system 100 illustrated in FIG. 1 . Each of the base station and the terminal may support communication based on an autonomous transmission scheme, and may be configured the same as or similar to the communication node 200 shown in FIG. 2 . First, a procedure for setting a terminal identifier may be performed between the base station and the terminal (S301). For example, the base station transmits a synchronization signal (eg, a primary synchronization signal (PSS), a secondary synchronization signal (SSS)) and system information (eg, a master information block (MIB), a system informationi block (SIB)). can be transmitted The terminal may receive the synchronization signal and system information from the base station, and may check the downlink frame timing of the base station based on the received synchronization signal and system information.

The UE may estimate the uplink frame timing based on the downlink frame timing, and may transmit a random access preamble to the base station based on the estimated uplink frame timing. The base station may receive the random access preamble from the terminal, may generate a random access response in response to the received random access preamble, and may transmit the generated random access response to the terminal. That is, a random access procedure between the terminal and the base station may be performed, and the terminal may check the uplink frame timing of the base station through the random access procedure, and may obtain a terminal identifier. The terminal identifier may be a cell-radio network temporary identifier (C-RNTI) used to identify the terminal, and the C-RNTI may consist of n bits. Here, n may be a positive integer. In the communication method based on the autonomous transmission method, the C-RNTI may be used as a signature of the terminal. For example, an interleaving procedure and a scrambling procedure may be performed based on the C-RNTI, and a DM-RS may be generated based on the C-RNTI.

Meanwhile, when there is data to be transmitted to the base station (ie, uplink data), the terminal may perform uplink transmission without an uplink grant of the base station. The UE may perform uplink transmission based on a single-carrier scheme or a multi-carrier scheme. A terminal performing uplink transmission based on the single-carrier scheme may be configured as follows.

4 is a block diagram illustrating a first embodiment of a terminal supporting a single-carrier scheme.

Referring to FIG. 4 , each of the terminals (eg, terminal #0, terminal #1, ..., terminal #(k-1)) includes a channel coding unit 410 , an interleaver 420 , and a signal processing unit. 430 , a scrambler 440 , and a padding unit 450 may be included. The channel coding unit 410 may perform coding on data. The coded data may include repeated data, and the coding rate may be 1/24. The interleaver 420 may perform interleaving on the coded data. In the interleaving procedure, a unique signature of the terminal may be inserted into the coded data. The signal processing unit 430 may perform a modulation function, a phase rotation function, a reference signal (RS) addition function, and the like. The scrambler 440 may perform scrambling on the signal obtained from the signal processing unit 430 . The padding unit 450 may add zero padding to the signal obtained from the scrambler 440 .

Meanwhile, a terminal performing uplink transmission based on the multi-carrier scheme may be configured as follows.

5 is a block diagram illustrating a first embodiment of a terminal supporting a multi-carrier scheme.

Referring to FIG. 5 , each of the terminals (eg, terminal #0, terminal #1, ..., terminal #(k-1)) includes a channel coding unit 510 , an interleaver 520 , and a signal processing unit 530 . , a scrambler 540 , an inverse fast Fourier transform (IFFT) and a cyclic prefix (CP) insertion unit 550 , and the like. The channel coding unit 510 , the interleaver 520 , the signal processing unit 530 , and the scrambler 540 each function as the channel coding unit 410 , the interleaver 420 , the signal processing unit 430 and the scrambler shown in FIG. 4 . The function of 440 may be the same or similar to that of 440 . The terminal supporting the multi-carrier scheme may include the IFFT and CP insertion unit 550 instead of the padding unit. The IFFT and CP insertion unit 550 may perform an IFFT operation on the signal obtained from the scrambler 540 and insert a CP into the signal on which the IFFT operation is completed.

Referring back to FIG. 3 , the terminal may perform coding on data ( S302 ). The coding procedure may be performed by the channel coding unit 410 shown in FIG. 4 or the channel coding unit 510 shown in FIG. 5 , and coded data may be represented by b(·). The channel coding units 410 and 510 may transmit coded data to the interleavers 420 and 520 .

The terminal may insert a signature (eg, a unique signature of the terminal) into the coded data. For example, the terminal may perform interleaving on the coded data based on the terminal identifier (S303). In the interleaving procedure, an interleaving sequence based on a terminal identifier may be used, and accordingly, interleaved data may include a unique signature of the terminal. The interleaving procedure may be performed by the interleaver 420 illustrated in FIG. 4 or the interleaver 520 illustrated in FIG. 5 , and interleaved data may be represented by s(·). The interleavers 420 and 520 of the terminal may generate s(·) based on Equation 1 below.

b(·) may indicate the output of the channel coding units 410 and 510, D may indicate the length (eg, number of bits) of b(·), and L _itlv may indicate the length of the interleaver. can direct The length of m may be 1/16 of the length of b(·), and the sequence of m may be set to randomly selected rows in a latin square matrix.

Characteristics of a Latin square matrix having a size of N×N (hereinafter, referred to as “N×N Latin square matrix”) may be as follows. Here, N may be an integer of 1 or more.

- Feature 1: The elements constituting each row of the Latin square matrix are 0, 1, … , (N-1), and elements within the same row of the Latin square matrix may have different values. For example, 0, 1, ... within the same row of a Latin square matrix. , (N-1) each can exist once.

- Feature 2: The elements constituting each column of the Latin square matrix are 0, 1, … , (N-1), and elements within the same column of a Latin square matrix may have different values. For example, 0, 1, ... within the same column of a Latin square matrix. , (N-1) each can exist once.

- Feature 3: When comparing two rows in one Latin square matrix, elements located in the same column in two rows may have different values.

- Feature 4: When comparing two columns in one Latin square matrix, elements located in the same row in the two columns may have different values.

When a cyclic shift is performed on the remaining columns except for the first column in a symmetric N×N Latin square matrix having a natural order, matrices having a size of N×N are can be created Since one matrix may be generated each time the cyclic shift is performed, (N-2) matrices may be additionally generated by performing the cyclic shift. Matrices generated by the cyclic shift may have characteristics of the Latin square matrix described above. For example, matrices generated by cyclic shift may also be Latin square matrices. Therefore, the total number of Latin square matrices may be (N-1).

(N-1) Latin square matrices may additionally have the following characteristics.

- Feature 5: When comparing two rows belonging to different Latin square matrices, only one of the N columns of the two rows can have the same element value.

- Feature 6: When comparing two columns belonging to different Latin square matrices, only one of the N rows of the two columns can have the same element value.

N×(N-1) rows can be obtained from (N-1) Latin square matrices, and when two rows are compared among N×(N-1) rows, the values of elements in the same column are The same case can only happen once. For "N=4", the Latin square matrix may be as follows.

6 is a conceptual diagram illustrating a first embodiment of a 4×4 Latin square matrix.

Referring to FIG. 6 , Latin square matrices #0 and #1 may satisfy features 1 to 6 described above. When D in Equation 1 is 64, the sequence of m may be set to one row belonging to the Latin square matrix #0 or #1. For example, the sequence of m may be set to [2, 1, 4, 3], which is the second row of the Latin square matrix #0. If m=[1, 2, 3, 4], the movement interval between the specific value belonging to b(·) and the specific value belonging to s(·) may be 16 bits or less.

For "N=5", the Latin square matrix may be as follows.

7 is a conceptual diagram illustrating a first embodiment of a 5×5 Latin square matrix.

Referring to FIG. 7 , Latin square matrices #0 and #1 may satisfy features 1 to 6 described above. When D in Equation 1 is 80, the sequence of m may be set to one row belonging to the Latin square matrix #0 or #1. For example, the sequence of m may be set to [2, 3, 5, 1, 4], which is the second row of the Latin square matrix #0. If m=[1, 2, 3, 4, 5], the movement interval between the specific value belonging to b(·) and the specific value belonging to s(·) may be 32 bits or less.

Referring back to FIG. 3 , in Equation 1, α ₀ , α ₁ , α ₂ , and α ₃ may be obtained from the terminal identifier (eg, C-RNTI) obtained in step S301. For example, the UE may obtain α ₀ , α ₁ , α ₂ , and α ₃ based on Equation 2 below.

The RNTI _cell may be the terminal identifier obtained in step S301, α ₀ may be [1 0 1 1], α ₁ may be [0 0 1 1], and α ₂ may be [0 0 0 1]. and α ₃ may be [0 1 0 0]. That is, the UE can divide the C-RNTI into quarters, change each of the values divided into quarters into decimal form, and designate each of the values changed in decimal form as α ₀ , α ₁ , α ₂ and α ₃ . can Each of α ₀ , α ₁ , α ₂ , and α ₃ may range from 0 to 15 . Alternatively, the range of each of α ₀ , α ₁ , α ₂ and α ₃ may be limited to 0 to 2, and in this case, the number of s _real (i) and s _imag (i) may be limited.

In Equation 1, D may be a multiple of L _itlv . When D is not a multiple of L _itlv , the terminal may determine n _padding based on Equation 3 below. n _padding may be the number of padding bits (eg, a sequence consisting of zeros). That is, n _padding having a length shorter than L _itlv may be added to D. Accordingly, interleaving may be performed for each binary bit vector unit of an output (eg, b(·)) of the channel coding units 410 and 510 .

Meanwhile, when the interleaving procedure is completed, the terminal may perform modulation on the interleaved data (eg, s ₆ (·) in Equation 1) ( S304 ). When the modulation procedure is completed, the terminal may perform a phase transformation on the modulated data (S305). The modulation procedure and the phase transformation procedure may be performed by the signal processing unit 430 illustrated in FIG. 4 or the signal processing unit 530 illustrated in FIG. 5 .

When the modulation procedure and the phase transformation procedure are completed, the terminal may scramble the data (S306). The scrambling procedure may be performed by the scrambler 440 shown in FIG. 4 or the scrambler 540 shown in FIG. 5 . For example, the scramblers 440 and 540 may perform scrambling on data acquired from the signal processing units 430 and 530 (eg, s _real (i), s _imag (i)), and the scrambled Data can be expressed as e(·). For example, the terminal may perform scrambling in a bit level unit based on Equation 4 below.

는 아래 수학식 5에 기초하여 생성될 수 있다.e _real (i) and e _imag (i) may be scrambled data, and D may indicate the length (eg, number of bits) of b(·).

may be generated based on Equation 5 below.

일 수 있다. x2(·)의 초기 시프트 레지스터 값은 아래 수학식 6에 기초하여 결정될 수 있다.The initial shift register value of x ₁ (·) is

can be The initial shift register value of x2(·) may be determined based on Equation 6 below.

Meanwhile, when the scrambling procedure is completed, the UE may perform an operation of adding a padding bit to the scrambled data (ie, e(·)) or an IFFT/CP insertion operation on the scrambled data (S307). For example, the padding unit 450 of the terminal shown in FIG. 4 may add a padding bit to the scrambled data. The IFFT and CP insertion unit 550 of the UE shown in FIG. 5 may perform an IFFT operation on scrambled data, and insert a CP into the data on which the IFFT operation is completed.

Meanwhile, the UE may generate an uplink signal including data (eg, data generated by steps S302 to S307 of FIG. 3 ) and a DM-RS. The UE may generate a DM-RS using a unique signature (eg, the UE identifier obtained in step S301 of FIG. 3 ). For example, the sequence number (u) of the DM-RS may be set based on Equation 7 below.

는 ZC(Zadoff-Chu) 시퀀스의 길이를 지시할 수 있고,

는 서브프레임 단위로 확산(spreading)되는 DM-RS 심볼(symbol)의 개수를 지시할 수 있다. DM-RS 심볼은 DM-RS의 전송을 위해 사용되는 심볼을 지시할 수 있다. 주파수 영역에서 DM-RS의 시퀀스(

)는 아래 수학식 8에 기초하여 생성될 수 있다.α ₀ , α ₁ , α ₂ and α ₃ can be calculated based on Equation 2,

may indicate the length of the ZC (Zadoff-Chu) sequence,

may indicate the number of DM-RS symbols that are spread in units of subframes. The DM-RS symbol may indicate a symbol used for DM-RS transmission. Sequence of DM-RS in the frequency domain (

) may be generated based on Equation 8 below.

의 루트(root) 값을 지시할 수 있고, v는 셀 특정(cell specific) 변수일 수 있다. 예를 들어, v는 0, 1 및 2 중에서 하나의 값으로 설정될 수 있다.

및 RNTI_cell 각각은 기지국에 의해 설정될 수 있으며, RNTI_cell는 기지국의 ID(예를 들어, 0 내지 503)일 수 있다. 비직교(non-orthogonal) 기반의 DM-RS를 위한

개의 시퀀스(

)는 아래 수학식 9에 기초하여 생성될 수 있다.q is

may indicate a root value of , and v may be a cell specific variable. For example, v may be set to one of 0, 1, and 2.

and each RNTI _cell may be configured by the base station, and the RNTI _cell may be an ID (eg, 0 to 503) of the base station. For non-orthogonal-based DM-RS

sequence (

) may be generated based on Equation 9 below.

가 11이고,

가 4인 경우, 길이가 11인

가 44개 생성될 수 있다.

는 r₀(n)부터 r₄₃(n)까지 정의될 수 있다.

가 4인 경우, 아래 표 1과 같이 직교 시퀀스(w_i)가 정의될 수 있다.Here, u may be a value calculated based on Equation 7 (eg, a sequence number of the DM-RS of the UE).

is 11,

is 4, the length is 11

44 can be generated.

can be defined from r ₀ (n) to r ₄₃ (n).

When is 4, an orthogonal sequence w _i may be defined as shown in Table 1 below.

When the number of DM-RS symbols spread by the orthogonal sequence of Table 1 (eg, orthogonal cover code) is 4, 4 symbols among symbols included in the subframe are DM-RS symbols can be used as

8 is a conceptual diagram illustrating a position of a DM-RS symbol in a subframe.

Referring to FIG. 8 , a subframe may include two slots, and each of the slots may include seven symbols. The subframe may be a subframe defined in an LTE-based communication system. For example, the length of the subframe may be 1 ms, and the length of each slot included in the subframe may be 0.5 ms. Of the 14 symbols included in the subframe, 4 symbols may be used for DM-RS transmission. For example, symbols #1, #5, #8, and #12 may be used as DM-RS symbols.

가 11이고,

가 4인 경우, 최대 44개의 상향링크 채널들을 위한 추정 동작이 동시에 수행될 수 있다. 수학식 9에 의하면, 하나의 그룹 내에서 서로 다른 DM-RS를 포함하는 44개의 상향링크 신호들(예를 들어, 비직교 상향링크 신호들)이 동시에 전송될 수 있으며, 기지국은 서로 다른 DM-RS를 사용하여 상향링크 채널을 추정할 수 있고, 추정된 상향링크 채널에 기초하여 44개의 상향링크 신호들을 구별할 수 있다.

is 11,

When is 4, an estimation operation for up to 44 uplink channels may be simultaneously performed. According to Equation 9, 44 uplink signals (eg, non-orthogonal uplink signals) including different DM-RSs in one group may be simultaneously transmitted, and the base station may transmit different DM-RSs. An uplink channel may be estimated using RS, and 44 uplink signals may be distinguished based on the estimated uplink channel.

On the other hand, when the terminal transmits an uplink signal through successive subframes, the sequence number of the DM-RS included in the uplink signal may be set as follows.

9 is a conceptual diagram illustrating a first embodiment of a sequence number of a DM-RS in a subframe.

)개의 단말들을 포함할 수 있고, 단말 #0의 C-RNTI는 "0000"으로 설정될 수 있고, 단말 #1의 C-RNTI는 "0001"로 설정될 수 있고, 단말 #2의 C-RNTI는 "0002"로 설정될 수 있고, 단말 #N의 C-RNTI는 "N-1"로 설정될 수 있다. z는 서브프레임 번호(예를 들어, 서브프레임 인덱스)를 지시할 수 있고, u는 단말 번호(예를 들어, 단말 인덱스)를 지시할 수 있다.9, group v is N (eg,

) terminals, the C-RNTI of terminal #0 may be set to "0000", the C-RNTI of terminal #1 may be set to "0001", and the C-RNTI of terminal #2 may be set to "0002", and the C-RNTI of terminal #N may be set to "N-1". z may indicate a subframe number (eg, subframe index), and u may indicate a terminal number (eg, terminal index).

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, … , N-7, N-6, N-5. Each of N-4, N-3, N-2 and N-1 may indicate the sequence number of the DM-RS used in the corresponding subframe. The sequence number of the DM-RS may be changed according to subframes. For example, the DM-RS sequence number may increase as the subframe number increases. Each of the terminals belonging to group v may use a different DM-RS sequence number at the same time point (eg, the same subframe).

10 is a conceptual diagram illustrating a second embodiment of a sequence number of a DM-RS in a subframe.

)개의 단말들을 포함할 수 있고, 단말 #0의 C-RNTI는 "0000"으로 설정될 수 있고, 단말 #1의 C-RNTI는 "0001"로 설정될 수 있고, 단말 #2의 C-RNTI는 "0002"로 설정될 수 있고, 단말 #N의 C-RNTI는 "N-1"로 설정될 수 있다. z는 서브프레임 번호(예를 들어, 서브프레임 인덱스)를 지시할 수 있고, u는 단말 번호(예를 들어, 단말 인덱스)를 지시할 수 있다.Referring to FIG. 10, group v is N (eg,

) terminals, the C-RNTI of terminal #0 may be set to "0000", the C-RNTI of terminal #1 may be set to "0001", and the C-RNTI of terminal #2 may be set to "0002", and the C-RNTI of terminal #N may be set to "N-1". z may indicate a subframe number (eg, subframe index), and u may indicate a terminal number (eg, terminal index).

0, 1, 2, 3, 4, 5, 6, 7, … , N-9, N-8, N-7, N-6, N-5. Each of N-4, N-3, N-2 and N-1 may indicate the sequence number of the DM-RS used in the corresponding subframe. The sequence number of the DM-RS may be changed according to subframes. For example, the DM-RS sequence number may decrease as the subframe number increases. Each of the terminals belonging to group v may use a different DM-RS sequence number at the same time point (eg, the same subframe).

On the other hand, when the base station does not inform the terminal of the start and end times of uplink transmission, the terminal may perform uplink transmission at any time. For example, the UE may select a time point at which uplink transmission is to be performed, may check the sequence number of the DM-RS based on the subframe number corresponding to the selected time point, and may check the DM-RS corresponding to the confirmed sequence number. and an uplink signal including data can be transmitted. In this case, the terminal may inform the base station of the start time and end time of the uplink transmission selected by the terminal.

The sequence number of the DM-RS that is changed according to time may be set based on the Latin square matrix. In the Latin square matrix shown in FIGS. 6 and 7 , a column may indicate a time (eg, a subframe), and one row may be used as a sequence number of a DM-RS for one terminal. For example, if one group includes 5 terminals and the length of the DM-RS sequence is 5, the sequence number of the DM-RS for the 5 terminals is the Latin square matrix #0 or # shown in FIG. It may be set based on 1. In this case, orthogonality between DM-RSs in one group may be maintained.

When the DM-RS is configured based on the Latin square matrix, demodulation performance in the receiver may be improved due to interference randomization characteristics. For example, since a DM-RS of a terminal belonging to group A collides with DM-RSs of different terminals instead of one terminal belonging to group B, an effect of interference randomization may occur. In this case, the base station may estimate the channel in the interval in which the interference occurs based on the DM-RS obtained in the interval in which the interference does not occur.

11 is a conceptual diagram illustrating a scenario in which DM-RS collision occurs.

11, terminals (eg, terminal #00, terminal #01, terminal #10, terminal #11) use subframes #z to #z+4 to transmit uplink signals (eg, packets) can be transmitted. Sequence numbers of DM-RSs used by UEs in subframes #z to #z+4 may be as shown in Table 2 below.

In subframe #z+2, the DM-RS of UE #00 may collide with the DM-RS of UE#10, and in subframe #z+3, the DM-RS of UE #00 is the DM-RS of UE#11. may collide with That is, since the DM-RS of UE #00 collides with DM-RSs of different UEs, the effect of interference randomization may occur.

Referring back to Figure 3, the terminal is data (eg, data generated by steps S302 to S307) and DM-RS (eg, DM-RS determined based on Equations 7 to 9, Latin square) An uplink signal including a DM-RS determined based on the matrix) may be transmitted to the base station (S308). The base station may receive an uplink signal from the terminal without an uplink grant. In addition, the base station may receive an uplink signal from other terminals as well as the terminal. That is, the base station may receive uplink signals from a plurality of terminals without an uplink grant. Uplink signals may be transmitted from a plurality of terminals to a base station through non-orthogonal resources. Each of the uplink signals is based on data (eg, data generated by steps S302 to S307) and DM-RS (eg, DM-RS determined based on Equations 7 to 9, Latin square matrix) DM-RS determined as ) may be included.

The base station may estimate the uplink channel of each of the plurality of terminals based on the DM-RS included in each of the uplink signals (S309). Since DM-RSs included in each of the uplink signals are set based on a Latin square matrix, collision between DM-RSs may not occur in some sections. Accordingly, the base station may estimate the uplink channel of each of the plurality of terminals based on the DM-RS obtained in the section in which no collision occurs.

The base station may acquire data included in each of the uplink signals based on the estimated uplink channel ( S310 ). Since the data included in the uplink signal is scrambled based on the terminal identifier (eg, a unique signature), the base station performs descrambling on the data included in the uplink signal based on the terminal identifier. It is possible to obtain scrambled data. That is, since the descrambling procedure is performed using the terminal's unique signature, the base station can distinguish data included in uplink signals received through non-orthogonal resources.

The base station may acquire demodulated data by performing demodulation on the descrambled data. Since data included in the uplink signal is interleaved based on a terminal identifier (eg, a unique signature), the base station performs deinterleaving on demodulated data based on the terminal identifier to deinterleave data. can be obtained. That is, since the deinterleaving procedure is performed using the terminal's unique signature, the base station can distinguish data included in uplink signals received through non-orthogonal resources. The base station may obtain decoded data of each of the plurality of terminals by performing decoding on the deinterleaved data.

■ DM- RS's Communication method based on group indicator

Meanwhile, the plurality of terminals may be classified into at least two groups, and in each of the groups, DM-RSs may be configured to be orthogonal, and DM-RSs between groups may be configured to be non-orthogonal. Even when DM-RS collision between groups occurs, the base station may decode an uplink signal (eg, a packet) by channel coding and interference randomization effects. However, when the collision range of the DM-RS is wide or when uplink transmission of many groups is performed at the same time, the probability of occurrence of a packet error may increase. Accordingly, in order to improve the packet decoding success rate in the base station, information indicating the possibility of DM-RS collision may be used.

12 is a conceptual diagram illustrating a first embodiment of uplink transmission based on a group indicator, and FIG. 13 is a conceptual diagram illustrating a position of a group indicator in a subframe.

12 and 13, each of the terminals (eg, terminal #00, terminal #01, terminal #10, terminal #11) are data, DM-RS and group indicator (eg, DM-RS) An uplink signal (eg, a packet) including a group indicator of That is, the uplink signal transmitted from the terminal to the base station in step S308 of FIG. 3 may further include a group indicator as well as data and DM-RS. The group indicator may indicate a group (eg, group A, group B) performing uplink transmission (eg, DM-RS transmission). The group indicator may be set differently for each group. For example, terminals belonging to group A (eg, terminal #00, terminal #01) may perform uplink transmission using the same group indicator. Terminals belonging to group B (eg, terminal #10, terminal #11) may perform uplink transmission using the same group indicator.

The group indicator may be located in a first symbol of a first subframe among consecutive subframes used for transmission of an uplink signal. In addition, the group indicator may be set according to a preset interval (eg, five subframes) in consecutive subframes used for transmission of an uplink signal. The group indicator may be a reference signal in which a single tone type is also configured. A reference signal used as a group indicator may be generated based on Equation 10 below.

x _n may be a reference signal used as a group indicator, and X _k may be determined based on Equation 11 below. Here, N _FFT may indicate the size of a fast Fourier transform (FFT).

가 정의될 수 있다. X_k는 k가 2인 경우를 제외하고 모두 0으로 설정될 수 있다. k가 2인 경우, 그룹 내에서 두 번째 서브-그룹이 설정될 수 있다.If k _sel is 2,

can be defined. All X _k may be set to 0 except for a case where k is 2. When k is 2, a second sub-group within the group may be established.

Meanwhile, the base station may receive an uplink signal from the terminal, and may identify a group performing uplink transmission based on a group indicator included in the uplink signal. The base station may predict the possibility of DM-RS collision in the identified group, and may acquire the DM-RS from the uplink signal in consideration of the predicted collision possibility. The base station may estimate the uplink channel between the base station and the terminal based on the DM-RS, and may acquire data included in the uplink signal based on the estimated uplink channel.

The methods according to the present invention may be implemented in the form of program instructions that can be executed by various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions recorded on the computer readable medium may be specially designed and configured for the present invention, or may be known and available to those skilled in the art of computer software.

Examples of computer-readable media include hardware devices specially configured to store and carry out program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as at least one software module to perform the operations of the present invention, and vice versa.

Although it has been described with reference to the above embodiments, it will be understood by those skilled in the art that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. will be able

Claims (20)

As a non-orthogonal transmission method performed by a terminal in a communication system,
generating data based on a signature used to identify the terminal from among a plurality of terminals belonging to the communication system;
generating an uplink signal including the data and a demodulation reference signal (DM-RS); and
transmitting the uplink signal to the base station without an uplink grant;
The signature is a cell-radio network temporary identifier (C-RNTI) configured by the base station, and the data is interleaved using a sequence configured based on the C-RNTI. delete The method according to claim 1,
The sequence is a value obtained by dividing the C-RNTI into quarters. The method according to claim 1,
The data is scrambled using a sequence set based on the C-RNTI. The method according to claim 1,
The sequence of the DM-RS is determined based on the C-RNTI within a range determined based on the length of the ZC (Zadoff-Chu) sequence and the number of DM-RS symbols spread in the subframe. Orthogonal transmission method. The method according to claim 1,
The DM-RS sequence is a sequence indicated by a randomly selected row in a latin square matrix, and the Latin square matrix includes a plurality of different sequences. The method according to claim 1,
The plurality of terminals are classified into at least two groups, and the uplink signal further includes a group indicator indicating a group to which the terminal belongs. 8. The method of claim 7,
The group indicator is located at a preset interval in consecutive subframes used for transmission of the uplink signal. 8. The method of claim 7,
The group indicator is located in a first symbol of at least one subframe among consecutive subframes used for transmission of the uplink signal. A method of operating a base station in a communication system, comprising:
Receiving uplink signals from a plurality of terminals through non-orthogonal resources without an uplink grant;
identifying each of demodulation reference signals (DM-RSs) included in uplink signals based on a signature of each of the plurality of terminals;
estimating an uplink channel of each of a plurality of terminals using each of the identified DM-RSs; and
acquiring data of each of the plurality of terminals from the uplink signals on the basis of the estimated uplink channel;
The plurality of terminals are classified into at least two groups, and the uplink signals further include a group indicator indicating a group to which each of the plurality of terminals belongs. 11. The method of claim 10,
The signature is a cell-radio network temporary identifier (C-RNTI) configured by the base station, and the data is obtained by performing a descrambling operation using a sequence set based on the C-RNTI. Way. 11. The method of claim 10,
The signature is a C-RNTI set by the base station, and the data is obtained by performing a deinterleaving operation using a sequence set based on the C-RNTI, and the sequence is obtained by dividing the C-RNTI into quarters. value, the method of operation of the base station. delete 11. The method of claim 10,
The group indicator is located at a preset interval in consecutive subframes used for transmission of each of the uplink signals. 11. The method of claim 10,
The group indicator is located in a first symbol of at least one subframe among consecutive subframes used for transmission of each of the uplink signals. As a terminal supporting non-orthogonal transmission in a communication system,
processor; and
At least one instruction executed by the processor comprises a memory (memory) stored,
The at least one command is
generate data based on a signature used to identify the terminal from among a plurality of terminals belonging to the communication system;
generating an uplink signal including the data and a demodulation reference signal (DM-RS); and
It is executed to transmit the uplink signal to the base station without an uplink grant,
The signature is a cell-radio network temporary identifier (C-RNTI) configured by the base station, and the data is scrambling using a sequence configured based on the C-RNTI. 17. The method of claim 16,
The data is interleaved using a sequence set based on the C-RNTI, and the sequence is a value obtained by dividing the C-RNTI into quarters. delete 17. The method of claim 16,
The DM-RS sequence is determined based on the C-RNTI within a range determined based on the length of the ZC (Zadoff-Chu) sequence and the number of DM-RS symbols spread in the subframe. . 17. The method of claim 16,
The plurality of terminals are classified into at least two groups, and the uplink signal further includes a group indicator indicating a group to which the terminal belongs.

Images