KR20210078411A - Method for modulating and demodulating signal, and apparatus for the same - Google Patents

Abstract

In accordance with the present invention, in transmitting and receiving data symbols, a transmitter diffuses (or spreads) each of the data symbols in a two-dimensional resource group, modulates each of the data symbols diffused in the two-dimensional resource group, and transmits the modulated data symbols. In addition, in receiving the data symbols, a receiver demodulates received signals and reversely diffuses (or despreads) the demodulated symbols diffused in the two-dimensional resource group with respect to each of the data symbols. To overcome delay spread and/or Doppler spread channel degradation, the receiver may perform channel equalization for the reversely diffused demodulated symbols after demodulation and/or may perform channel equalization for the back-diffused data symbols. The present invention tolerates interference among the data symbols to a proper level and enhances the diversity gain of a channel.

Description

Method for modulating and demodulating signal, and apparatus for the same

The present invention relates to signal modulation and demodulation, and specifically, by spreading (or spreading) each data symbol in a two-dimensional resource group to modulate and transmit data symbols, demodulate a received signal, A method of demodulating by despreading (or despreading) demodulation symbols spread in a 2D resource group.

The transmitter modulates the signal to be transmitted to the receiver (data symbol, pilot symbol, reference signal, and various other types of symbols or signals; hereinafter, it is collectively referred to as a signal or data symbol, unless otherwise specified), and then the corresponding modulation A signal is radiated or emitted through an antenna or emitter and transmitted to the corresponding receiver. The receiver absorbs or collects a signal transmitted from the transmitter through an antenna or a collector, and demodulates the received signal to receive a desired signal to be transmitted by the transmitter.

In general, a signal to be transmitted through signal modulation is transmitted through a channel or medium on a transmission waveform, and the transmitted original signal can be restored through demodulation of the received signal using a reception waveform related to the transmission waveform.

In the broadband communication system, in transmitting a signal, the modulation and demodulation method of orthogonal frequency division multiplexing (OFDM) or orthogonal frequency division multiple access (OFDMA) is used, which has excellent frequency efficiency and is simple to implement. have. One of the characteristics of the modulation/demodulation method is to map and transmit data symbols to time-frequency two-dimensional resources (including mapping only time resources or frequency resources as a special case), and time-frequency two-dimensional Resources are spaced apart by OFDM symbol spacing on the time axis and by subcarrier spacing on the frequency axis. In an ideal channel, data symbols transmitted on time-frequency two-dimensional resources are orthogonal to each other.

The transmitted modulated signal undergoes delay-spread and/or Doppler-spread (or frequency-selective and/or time-selective) channels, and data symbols transmitted on different resources may lose orthogonality. On the other hand, when one data symbol is transmitted on one time-frequency two-dimensional resource, if the channel on the corresponding resource has a low channel gain value due to channel degradation such as fading, it may be difficult to successfully detect or decode the corresponding data symbol.

It is an object of the present invention to solve the above problems, in consideration of the interference between data symbols and the diversity gain of the channel experienced by each data symbol, a two-dimensional (2D) that can improve data rate and data transmission reliability. Part) to provide a spread multicarrier modulation method and a transmitter to which the method is applied.

It is an object of the present invention to solve the above problems, in consideration of interference between data symbols and a diversity gain of a channel experienced by each data symbol, two-dimensional (partial) spreading that can improve data rate and data transmission reliability To provide a multi-carrier demodulation method and a receiver to which the method is applied.

A transmitter according to an embodiment of the present invention for achieving the above object spreads (or spreads) each data symbol in a two-dimensional resource group and modulates each data symbol spread in the two-dimensional resource group to transmit. can In addition, a receiver according to an embodiment of the present invention for achieving the above object demodulates a received signal and despreads (or despreads) demodulated symbols spread in a two-dimensional resource group for each data symbol. can To overcome delay spread and/or Doppler spread channel degradation, the receiver may perform channel equalization on the despread demodulated symbols after demodulation and/or perform channel equalization on the despread data symbols.

In the present invention, by transmitting data symbols using a devised modulation/demodulation method, interference between data symbols is allowed to an appropriate level and diversity gain of a channel experienced by each data symbol is improved to improve/improve SINR or channel capacity or achievable rate or decrease BER or SER or BLER.

In addition, by setting the spreading length so that the multicarrier (MC) symbol length for spreading is not excessively large, on-the-fly decoding of the spreading resource group unit can be performed to reduce the reception processing delay. have.

1 is a conceptual diagram illustrating a two-dimensional (partial) spread multicarrier modulation process in a transmitter according to an embodiment of the present invention.
2 is a conceptual diagram illustrating examples in which data symbols and reference signal(s) are mapped to resources on a first two-dimensional domain according to an embodiment of the present invention.
3 and 4 are conceptual diagrams for explaining the relationship between data symbols of codewords, resource mapping on a first two-dimensional domain, and spreading on a second two-dimensional domain according to an embodiment of the present invention.
5 is a conceptual diagram illustrating a two-dimensional (partial) spread multicarrier demodulation process in a receiver according to an embodiment of the present invention.
6 is a block diagram illustrating an embodiment of a communication node constituting a communication system.

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention. In describing each figure, like reference numerals have been used for like elements.

Terms such as first, second, A, and B 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. The term “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 is understood that the other component may be directly connected or connected to the other component, but other components may exist in between. it should be On the other hand, when it is mentioned 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 should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the 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.

In the following, a wireless communication network to which embodiments according to the present invention are applied will be described. A wireless communication network to which embodiments according to the present invention are applied is not limited to the content described below, and embodiments according to the present invention may be applied to various wireless communication networks.

In the case of the modulation/demodulation method, multiplexing of data symbols for a single user (or user terminal) and multiple access (MA) of multiple users (or user terminals) may be considered.

First, the transmitter 100 may generate data symbols through the following process.

Information (or message) bits to be transmitted may be input to a channel encoding unit, and encoded bits suitable for a given code rate may be output through a channel encoding process. At this time, the channel encoding unit calculates and adds a cyclic redundancy check (CRC) bit of a transport block (TB), (when the transport block size exceeds a certain size), code block segmentation ( That is, dividing the transport block to which CRC bits are added into a plurality of code blocks), calculating and adding CRC bits for each code block, channel encoding for each code block, and rate matching for each code block (CB) Matching: RM) and hybrid automatic repeat request (HARQ) processing, bit interleaving, code block concatenation (ie, concatenating coding bits of multiple code blocks) functions in whole or in part. can In this case, if the transport block is not divided into a plurality of code blocks, it is unnecessary to calculate and add CRC bits for each code block, and the remaining functions are performed on the transport block itself to which the CRC bit is added, and the last code block concatenation is unnecessary In the rate matching, a code rate may be adjusted by performing puncturing, shortening, and/or repetition on coded bits that are output of channel encoding. As channel encoding, various channel encoding methods such as turbo code, low density parity check (LDPC) code, and polar code can be applied. The coded bits output from the channel encoding unit may be subjected to scrambling (ie, bit level scrambling), then input to a modulation/constellation mapper, and may be output as data symbols through a data modulation process.

Hereinafter, each set of data symbols output through a channel encoding process and a data modulation process for each transport block is referred to as a codeword.

Additionally, the transmitter 100 may perform the following additional procedure on data symbols (or symbols spread on resources on a second two-dimensional domain described below) for multi-antenna transmission. A transport block and a codeword may have a one-to-one correspondence. The transmitter may map data symbols belonging to the codeword(s) (or symbols spread to resources on the second two-dimensional domain described below) to the layer(s). Accordingly, when a plurality of transport blocks are transmitted, codewords corresponding to the respective transport blocks may be mapped to different layer(s). Data symbols belonging to different codewords (or symbols spread to resources on a second 2D domain described below) may be restricted to be mapped only to different layers. Data symbols mapped to each layer (or symbols spread to resources on a second two-dimensional domain described below) may be spread to each antenna port through multi-antenna preprocessing.

The transmitter 100 converts the output signals into analog signals through an analog-to-digital converter (ADC) after a two-dimensional (partial) spread multicarrier modulation process described below in the baseband, and then passes through the analog/RF terminal to the antenna. to the receiver 200 through

Next, the receiver 200 converts the RF band signal received through the receiving antenna from the transmitter 100 into a digital signal through an analog/RF terminal through a digital-to-analog (DAC), and then converts it into a digital signal in the baseband. The two-dimensional (partial) despread multicarrier demodulation process described in can be performed.

The receiver 200 may decode the data symbols detected after the demodulation process through the following process. The detection data symbols are input to a modulation/constellation demapper to output log likelihood (LLR) for the coded bits. After descrambling the LLR of the coded bits output in this way, they are input to the channel decoding unit and subjected to channel decoding, and the information bits of the corresponding transport block and the result of whether the transport block has passed the CRC or not are output. If the CRC is passed for the transport block, the decoding succeeds. Otherwise, it is regarded as a decoding failure. When the codeword is composed of a plurality of code blocks, the channel decoding unit performs code block segmentation/deconcantenation into a plurality of code blocks, and performs bit deinterleaving for each code block, and rate dematching for each code block. dematching) and LLR combining, channel decoding for each code block, CRC verification for each code block, code block concatenation/desegmentation (that is, concatenating decoded bits for each code block) ), and undergoes transport block CRC verification. When the received codeword is not composed of a plurality of code blocks, code block division is unnecessary and the remaining functions are performed on the codeword itself. CRC check for each code block and code block concatenation are unnecessary, and channel decoding Whether or not the CRC has passed may be checked from the information bits and CRC bits of the corresponding transport block that are the outputs of .

Hereinafter, in the case of downlink (DL), the transmitter 100 may be a base station or a repeater, or a transmission point (TP) or a transmission and reception point (TRP), and the receiver 200 is a device (device). or mobile) or user equipment (UE). In the case of uplink (UL), the transmitter 100 may be a terminal or a user terminal, and the transmitter 100 may be a base station or a repeater, or a transmission point or a transmission/reception point. Unless otherwise stated, the transmitter 100 and the receiver 200 do not distinguish a link direction. In the case of sidelink (SL), the transmitter and the receiver may be different terminals.

Hereinafter, main parameters used to describe the modulation process of the transmitter 100 and the demodulation process of the receiver 200 may be summarized as shown in Table 1 below.

In addition, the notation used to describe the modulation process below can be organized as shown in Table 2 below.

Two-dimensional (partial) spread multicarrier modulation process

The transmitter 100 transmits each data symbol to the receiver 200 on individual waveforms. It is preferable that different waveforms on which different data symbols are carried and transmitted are designed to be orthogonal or close to orthogonal.

1 is a conceptual diagram illustrating a two-dimensional (partial) spread multicarrier modulation process in a transmitter according to an embodiment of the present invention.

Referring to FIG. 1 , a first mapper 110 of a transmitter 100 converts data symbols output from a channel encoding unit and a subsequent data symbol modulator (not shown) to resources on a first 2D domain. can be mapped to Next, the preprocessor 120 of the transmitter 100 preprocesses (or spreads) each data symbol mapped to the resources on the first two-dimensional domain to the resources on the second two-dimensional domain. precoding or pre-processing). Next, the second mapper 130 of the transmitter 100 may map the preprocessed data symbols to resources on the second two-dimensional domain. Next, the modulator 140 of the transmitter 100 modulates (ie, multi-carrier modulation) each data symbol mapped to resources on the second two-dimensional domain after pre-processing into individual waveforms for each resource on the second two-dimensional domain. ) and transmit it to the receiver 200 . Each function of the two-dimensional (partial) spread multicarrier modulation process is detailed below.

In the above, the 2D partial diffusion refers to diffusion into a resource group composed of some resources rather than all resources on the second 2D domain. However, diffusion to all resources is also not excluded.

A delay-Doppler or Doppler-delay domain as an embodiment of the first two-dimensional domain, and a frequency (or subcarrier)-time (or multiple A carrier symbol (frequency-time or subcarrier-MC symbol) or time (or multicarrier symbol)-frequency (or multicarrier) (time-frequency or MC symbol-subcarrier) domain may be considered.

When transmitting as multiple-input and multiple-output (MIMO) or multiple-input and single-output (MISO) using a multiple antenna port, preprocessing for multiple antenna transmission is It may be performed between the first mapper 110 and/or the preprocessor 120 and the second mapper 130 . In the former case, the operation of the first mapper 110 may be performed for each antenna port that is the output of preprocessing for multi-antenna transmission. In the latter case, the operations of the first mapper 110 and the preprocessor 120 are performed for each layer that is the input of preprocessing for multi-antenna transmission, and after pre-processing for multi-antenna transmission is performed, the output of pre-processing for multi-antenna transmission The operations of the second mapper 130 and the modulator 140 may be performed for each in-antenna port.

Hereinafter, each step of the two-dimensional (partial) spread multicarrier modulation process in the transmitter 100 according to an embodiment of the present invention will be described in detail.

(One) Mapping of data symbols to resources on the first two-dimensional domain (operation of the first mapper 110 )

The first mapper 110 may map data symbols to resources on the first two-dimensional domain. Additionally, for some resources, a demodulation reference signal (DMRS) or a reference signal (RS) for other purposes may be mapped instead of data symbols. Some resources may be left blank without mapping (or a guard resource may be placed) in consideration of interference between resources on the first two-dimensional domain.

2 is a conceptual diagram illustrating examples in which data symbols and reference signal(s) are mapped to resources on a first two-dimensional domain according to an embodiment of the present invention.

The first example indicates that one reference signal is mapped to a centrally located resource and data symbols are mapped to the remaining resources, and the second example maps one reference signal to a centrally located resource and eight resources surrounding it. (null resources) indicates that data symbols are mapped to the remaining resources without mapping, and the third example indicates that reference signals are mapped to nine centrally located resources and data symbols are mapped to the remaining resources. If symbols spread to different resource groups on the second two-dimensional domain are transmitted (described in detail below), channels experienced in each resource group on the second two-dimensional domain are different, so that each channel on the second two-dimensional domain is different. It may be necessary to transmit the reference signal(s) to the resource(s) on the first 2D domain corresponding to each resource group.

Resources on the first 2D domain that are spread on different resource groups on the second 2D domain may be separated and despread on the second 2D domain, so that they are spread on different resource groups on the second 2D domain. It may be advantageous to contiguously allocate the symbols to be assigned to resources on the first two-dimensional domain, whereas data symbols transmitted in resources on the first two-dimensional domain that are spread in the same resource group on the second two-dimensional domain are the second. 1 Since channel spreading in the 1 2D domain may cause interference with each other, it may be advantageous to allocate them as far apart as possible. Data symbols spread and transmitted to one specific receiver in the same resource group on the 2nd 2D domain For , it may be preferable to be mapped to resources on the first two-dimensional domain in an interleaved pattern.

3 and 4 are conceptual diagrams for explaining the relationship between data symbols of codewords, resource mapping on a first 2D domain, and spreading on a second 2D domain according to an embodiment of the present invention.

Referring to FIG. 3 , an example in which 12 data symbols in one codeword are mapped to 12 resources on a first 2D domain, and each 4 data symbols are spread into the same resource group on a second 2D domain is shown It can be seen that each of the four data symbols spread into each same resource group on the second 2D domain is mapped to the resource grid on the first 2D domain in an interleaved pattern, respectively.

On the other hand, referring to FIG. 4 , symbols spread into different resource groups on the second 2D domain are distributed and mapped to independently separated grids (ie, three grids) on the first 2D domain. can be considered

For multiple access by different users, data symbols for different users may be mapped without overlapping by dividing all resources on the first 2D domain. Additionally or alternatively, data symbols for different users may be mapped non-overlapping by dividing all resources on the second 2D domain for multiple access of different users. The latter case will be described in detail in the operation part of the second mapper 130 below. In the case of non-orthogonal multiple access, resources on the first two-dimensional domain and/or resources on the second two-dimensional domain may be mapped to different users by overlapping all or part of them.

번째 사용자를 위한(

번째 사용자에게 전송하거나

번째 사용자로부터 전송되는)

번째 데이터 심볼을 제1 2차원 도메인 상의

번째 2차원 자원으로 매핑하는

번째 사용자를 위한 매퍼(mapper)

를 아래 수학식 1과 같이 표현할 수 있다.

for the second user (

to the second user, or

sent from the second user)

th data symbol on the first two-dimensional domain

mapping to the second two-dimensional resource

mapper for the second user

can be expressed as Equation 1 below.

인 경우와 동일하게 간주할 수 있다.

번째 사용자의

번째 데이터 심볼이 매퍼

에 의해 제1 2차원 도메인 상의

번째 2차원 자원으로 매핑된 데이터 심볼

는 아래 수학식 2와 같이 표현할 수 있다.However, since the user terminal transmits only its own data symbols in the uplink and the sidelink,

can be considered the same as in the case of

second user's

The second data symbol is the mapper

on the first two-dimensional domain by

data symbol mapped to the second two-dimensional resource

can be expressed as in Equation 2 below.

(2) Preprocessing for spreading data symbols to resources on the second two-dimensional domain (operation of the preprocessor 120 )

번째 사용자를 위한

번째 데이터 심볼

에 대한 제2 2차원 도메인 상의 자원들로의 스프레딩을 위해 전처리된 데이터 심볼 벡터

는 아래 수학식 3과 같이 표현할 수 있다.

for the second user

second data symbol

Preprocessed data symbol vector for spreading to resources on the second two-dimensional domain for

can be expressed as in Equation 3 below.

인 벡터

를 아래 수학식 4 와 같이 표현할 수 있다.In order to spread the resources on the second 2D domain in the above, the spreading process may include summing the preprocessed data symbols as shown in the following equation. The length of the sum of all the preprocessed data symbols is

phosphorus vector

can be expressed as in Equation 4 below.

는 수학식 5와 같이 각 전처리 벡터들로 구성된 행렬

와 각 데이터 심볼들로 구성된 벡터

의 곱으로 구할 수 있다.Sum vector of the above preprocessed data symbols

is a matrix composed of each preprocessing vector as shown in Equation 5

and a vector of data symbols

can be obtained by multiplying

Spreading data symbols to resources on the second two-dimensional domain may spread over all (available) resources on the second two-dimensional domain and may partially spread over some (available) resources. Here, as an example of the available resources, when multi-carriers are considered, the available resources on the second 2D domain include the DC sub-carriers and/or the remaining sub-carriers other than the guard sub-carriers for satisfying the spectrum mask as available resources. Can be used. In the partial spreading, as in the examples of FIGS. 3 and 4, some data symbols for one codeword are spread to resources in the same resource group on the second two-dimensional domain, and the second data symbols are separated between some data symbols. It may include spreading to resources in different resource groups on the two-dimensional domain.

In addition, in partial spreading, various structured forms may be considered in a mapping pattern to resources on the second 2D domain. On the second two-dimensional domain, localized or contiguous mapping composed of contiguous resources, interleaved pattern composed of resources that are distributed at regular intervals, and contiguous resources A group-wise-distributed mapping of resources in which the resource groups consisting of ? are distributed in a distributed manner may include a group-wise-distributed mapping, and a combination of these mappings.

As described above, for multiple access of different users, data symbols for different users may include the following types for the degree of overlap of resources spread on the second two-dimensional domain.

Complete overlap: When resources on the second 2D domain are spread so that they are completely overlapped between different users, it is desirable to map the resources on the first 2D domain so that they do not overlap each other in the case of non-orthogonal multiple access. can In the case of non-orthogonal multiple access, resources on the first two-dimensional domain may overlap each other and be mapped.

Partial overlap: When the spreading resources on the second 2D domain are partially overlapped between different users, the size of the spreading window does not have a rectangular shape and a roll-off factor like the Nyquist window (roll-off factor) factor) is greater than 1 and in the case where the boundary of the window is gradually attenuated, some of the spreading resources belonging to different resource groups on the second 2D domain may overlap each other. Contrary to this, in the case of supporting non-orthogonal multiple access, only some of the spreading resources on the second 2D domain may be overlapped between different users (for example, sparse overlap may be considered to reduce reception computational complexity).

Non-overlapping: When resources on the second two-dimensional domain are spread so that they do not overlap at all between different users, when synchronization between different users is imperfect and/or when they have different channel spreads; and / or when setting different numerology for modulation (for example, subcarrier spacing in OFDM or OFDM symbol spacing), do not allow overlapping of spreading resources on the second two-dimensional domain between different users. It may be preferable not to.

It may additionally include all or some combinations of the above nesting types. For example, allow full nesting between user A and user B and between user C and user D, no nesting between user A and user C and user D, and no nesting between user B and user C and user D. may consider not.

In addition to the above multiple access of different users, in multiplexing a plurality of data symbols for one user, the following types may be included with respect to the degree of overlap of resources in which different data symbols are spread on the second two-dimensional domain. can

full nesting

Partial overlap

Non-overlapping

It may additionally include all or some combinations of the above nesting types.

번째 2차원 자원에서 제2 2차원도메인 상의 자원들로 스프레딩 시키기 위한 전처리 벡터

를 아래 수학식 6과 같이 특수 경우로써 표현할 수 있다.on the first two-dimensional domain for each of the existing modulation schemes.

Preprocessing vector for spreading from the second 2D resource to resources on the 2nd 2D domain

can be expressed as a special case as in Equation 6 below.

(3) Mapping of preprocessed data symbols to resources on a second two-dimensional domain (operation of second mapper 130)

번째 전처리된 데이터 심볼

을 제2 2차원 도메인 상의

번째 2차원 자원으로 매핑하는 매퍼

를 아래 수학식 7과 같이 표현할 수 있다.The second mapper 130 maps the preprocessed (or added after preprocessing) data symbols to resources on the second 2D domain.

second preprocessed data symbol

on the second two-dimensional domain

Mapper that maps to the second 2D resource

can be expressed as in Equation 7 below.

의 한 예를 아래 수학식 8과 같이 들 수 있다.said mapper

An example of can be given as in Equation 8 below.

로부터 상기 매퍼

에 따라 제2 2차원 도메인 상의 각 자원에 스프레딩된(즉, 전처리 후 매핑된) 심볼들로 구성된

행렬

를 아래 수학식 9와 같이 구성할 수 있다.The preprocessed symbol vector above

from the mapper

Consists of symbols spread (that is, mapped after preprocessing) to each resource on the second 2D domain according to

procession

can be configured as in Equation 9 below.

(4) Multi-carrier modulation on the second two-dimensional domain (operation of the modulator 140 )

(또는

)에 대해 제2 2차원 도메인 상의 자원 별로 개별적인 파형에 변조시켜 이들을 가산하여 전송한다.

번째 다중반송파 심볼의 변조 신호는 아래 수학식 10과 같이

번째 다중반송파 심볼 내 각 부반송파에서의 변조 신호

를 합하여 구한다.The modulator 140 is a sum of data symbols spread (ie, mapped after preprocessing) to resources on the second two-dimensional domain.

(or

) for each resource on the second two-dimensional domain, modulates individual waveforms, adds them, and transmits them.

The modulated signal of the th multi-carrier symbol is as shown in Equation 10 below.

Modulated signal on each subcarrier in the th multicarrier symbol

is obtained by summing

번째 다중반송파 심볼의 변조 신호 벡터

은 아래 수학식 11과 같이

번째 다중반송파 심볼을 위한 변조 행렬

과

번째 다중반송파 심볼 내 스프레딩된 데이터 심볼들의 합으로 구성된 벡터

의 곱으로 표현할 수 있다.For the multicarrier modulation on the second two-dimensional domain,

modulated signal vector of the th multicarrier symbol

is as in Equation 11 below

modulation matrix for the th multicarrier symbol

and

vector consisting of the sum of the spread data symbols in the th multicarrier symbol

It can be expressed as the product of

번째 다중반송파 심볼의 변조 신호

에 추가적으로 전대역/부대역 필터링(wideband/subband filtering) 그리고/또는 TTI의 양 경계에 위치한 다중반송파 심볼에 추가적인 펄스 성형(pulse shaping)이 추가될 수 있다. 전대역 필터링은 대역외방출(out-of-band emission: OOBE)의 완화 등을 위해 사용될 수 있다. 부대역 필터링은 대역외방출 완화뿐 아니라 부대역 또는 부대역 그룹 단위의 다중 접속 그리고/또는 뉴머롤로지 다중화를 수행하는 경우 부대역 또는 부대역 그룹 간 간섭 완화 등을 위해 사용될 수 있다. TTI의 양 경계에 위치한 다중반송파 심볼에 적용하는 추가적인 펄스 성형은 전송 지연을 제약하기 위한 절단(truncation) 또는 TTI 간 다중 접속으로 인한 간섭 완화 등을 위해 사용될 수 있다. 이러한 추가적인 과정들을 변조 파형

에 포함시켜 표현할 수도 있다.

Modulated signal of the second multicarrier symbol

Additionally, wideband/subband filtering and/or additional pulse shaping may be added to multi-carrier symbols located at both boundaries of the TTI. Full-band filtering may be used for mitigation of out-of-band emission (OOBE), and the like. Subband filtering may be used not only for mitigating out-of-band emission but also for mitigating interference between subbands or subband groups when performing multiple access and/or numerology multiplexing on a subband or subband group basis. Additional pulse shaping applied to multi-carrier symbols located at both boundaries of the TTI may be used for truncation to limit transmission delay or to mitigate interference due to multiple access between TTIs. These additional processes are combined with the modulating waveform.

It can also be expressed by including

번째 2차원 자원에서의 변조 파형

을 아래 수학식 12와 같이 특수 경우로써 표현할 수 있다.on the second two-dimensional domain above for each of the existing modulation schemes.

Modulation waveform at the second 2D resource

can be expressed as a special case as in Equation 12 below.

이 다중반송파 심볼 간격

보다 큰 경우 다중반송파 심볼 간 중첩-가산(overlap-add)을 제2 2차원 도메인 상의 다중반송파 변조에 포함해야 할 수 있다. 중첩-가산된

번째 변조 신호

은 아래 수학식 13과 같이 표현할 수 있다.length of modulating waveform

This multicarrier symbol spacing

In larger cases, an overlap-add between multicarrier symbols may need to be included in the multicarrier modulation on the second two-dimensional domain. nested-added

second modulated signal

can be expressed as in Equation 13 below.

(5) Setting the two-dimensional resource grid interval on the first two-dimensional domain and the two-dimensional resource group size on the second two-dimensional domain

When the delay-Doppler domain is considered as the first two-dimensional domain and the time-frequency domain is considered as the second two-dimensional domain, the frequency and time diversity gain can be obtained as large as possible while the adjacent subcarrier interference and adjacent symbol interference are small. Thus, it may be desirable to set the multicarrier symbol spacing and subcarrier spacing and the spreading length over the multicarrier symbols in the time-frequency domain and the spreading length across the subcarriers.

(6) How to map data symbols

One codeword is composed of a plurality of data symbols, and each data symbol mapped to each resource on the first two-dimensional domain is spread on resources on the second two-dimensional domain and transmitted on a multi-carrier waveform. When the size of the resource group on the second 2D domain to be spread is small, it may be transmitted through the resource group on the plurality of second 2D domains. In this case, since the diversity gain may not be sufficiently obtained in the resource group on the second 2D domain having a relatively small size, resource groups on the plurality of second 2D domains are distributed in order to efficiently obtain the diversity gain. , so that it can be mapped distributedly.

(7) Reference signal assignment

When the resource group size on the second 2D domain is set to be small in order to mitigate interference (eg, neighbor subcarrier interference and adjacent symbol interference) in adjacent resources on the second 2D domain due to channel spreading, resources on the second 2D domain It may be necessary to allocate a demodulation reference signal (on the first 2D domain) to each group. However, since the resource interval on the first 2D domain is increased, the size of the guard region of the demodulation reference signal on the first 2D domain may be reduced or the sequence length of the demodulation reference signal may be reduced.

(8) Resource mapping on a first two-dimensional domain of symbols in a codeword followed by spreading onto a second two-dimensional domain

Each data symbol mapped to a resource on the first two-dimensional domain is spread to resources in a two-dimensional resource group on the second two-dimensional domain. Some data is spread in a 2D resource group on the same second 2D domain, while some data is spread in a 2D resource group on a different second 2D domain. The 2D resource groups on the second 2D domain do not overlap each other and are spaced apart to obtain a diversity gain. In order for channel-coded coded bits to obtain diversity gain, it may be necessary to properly design a bit interleaver for coded bits in consideration of spreading or to appropriately group and arrange spreading resources in consideration of the bit interleaver.

Two-dimensional (partial) despread multicarrier demodulation process

The receiver 200 may receive the two-dimensional (partial) spread multicarrier modulated signals transmitted from the transmitter 100, and may perform a two-dimensional (partial) despread multicarrier demodulation process.

5 is a conceptual diagram illustrating a two-dimensional (partial) spread multicarrier demodulation process in a receiver according to an embodiment of the present invention.

The demodulator 210 of the receiver 200 may demodulate the signal received from the transmitter 100 into the second 2D domain. Next, the first demapper 220 of the receiver 200 may demap the demodulated symbols to resources on the second 2D domain. Next, the first channel equalizer 230 of the receiver 200 may perform channel estimation and channel equalization for the second 2D domain channel equalization of the demulated symbols after demodulation (if necessary). . Next, the post-processing unit 240 of the receiver 200 maps each symbol demapping (or subjected to channel equalization after demapping) from resources on the second two-dimensional domain to resources on the first two-dimensional domain. In order to despread data symbols, post-processing (or postcoding or deprecoding or post-processing) may be performed. Next, the second demapper 250 of the receiver 200 may demap the post-processed data symbols to resources on the first 2D domain. Next, the second channel equalizer 260 of the receiver 200 performs a channel estimation for the first two-dimensional domain channel equalization of the despread (i.e., demapped after post-processing) data symbols (if necessary). and channel equalization thereof. The execution order of the first demapper 220 and the first channel equalizer 230 may be reversed. Also, the execution order of the second demapper 250 and the second channel equalizer 260 may be reversed.

In the above, 2D partial despreading means despreading from within a resource group composed of some resources rather than all resources on the second 2D domain. As a special case, partial despreading may not exclude despreading from all resources.

A delay-Doppler or Doppler-delay domain as an embodiment of the first two-dimensional domain, and a frequency-time or time as an embodiment of the second two-dimensional domain - A time-frequency domain may be considered.

When receiving with multiple input multiple output or single-input and multiple-out (SIMO) using a multiple antenna port, post-processing for multiple antenna reception is performed by the first channel equalizer 230 and/or It may be performed together with the operation of the second channel equalizer 260 . In the former case, the operations of the demodulator 210 and the first demapper 220 are performed for each antenna port, which is an input of post-processing for multi-antenna reception, and a post-processing unit for each layer that is an output of post-processing for multi-antenna reception ( 240 , the second demapper 250 , and the second channel equalizer 260 may be operated. In the latter case, the demodulator 210 , the first demapper 220 , the first channel equalizer 230 , the postprocessor 240 , and the second demapper for each antenna port that is an input of post-processing for multi-antenna reception. The operation of 250 may be performed.

Hereinafter, each step of the two-dimensional (partial) spread multicarrier demodulation process in the receiver according to an embodiment of the present invention will be described in detail.

(One) Multi-carrier demodulation on the second two-dimensional domain (operation of the demodulator 210 )

번째 다중반송파 심볼 내

번째 부반송파의 복조 신호

는 아래 수학식 14와 같이

번째 다중반송파 심볼의 수신 신호 벡터

와

번째 복조 파형 벡터

을 내적하는 것으로 표현할 수 있다.The demodulator 210 may perform multicarrier demodulation on the signals received from the transmitter 100 in the second 2D domain. Prior to demodulation, the receiver may need to perform time and frequency synchronization with the transmitter.

in the second multicarrier symbol

demodulation signal of the second subcarrier

is as in Equation 14 below

Received signal vector of the th multicarrier symbol

Wow

2nd demodulation waveform vector

can be expressed as a dot product.

번째 다중반송파 심볼의 복조 신호 벡터

는 아래 수학식 15와 같이

번째 다중반송파 심볼을 위한 복조 행렬

에 Hermitian(또는 conjugate transpose)을 취한 행렬과

번째 다중반송파 심볼의 수신 신호 벡터

의 곱으로 표현할 수 있다.For the above multicarrier demodulation onto the second two-dimensional domain,

The demodulated signal vector of the th multicarrier symbol

is as in Equation 15 below

Demodulation matrix for the th multicarrier symbol

A matrix taking Hermitian (or conjugate transpose) on

Received signal vector of the th multicarrier symbol

It can be expressed as the product of

번째 다중반송파 심볼의 다중반송파 복조 이전에 추가적으로 전대역/부대역 필터링(wideband/subband filtering) 그리고/또는 TTI의 양 경계에 위치한 다중반송파 심볼에 추가적인 펄스 성형(pulse shaping)이 추가될 수 있다. 전대역 필터링은 대역외 방출(out-of-band emission: OOBE)의 완화 등을 위해 사용될 수 있다. 부대역 필터링은 대역외 방출 완화뿐 아니라 부대역 또는 부대역 그룹 단위의 다중 접속 그리고/또는 뉴머롤로지 다중화를 수행하는 경우 부대역 또는 부대역 그룹 간 간섭 완화 등을 위해 사용될 수 있다. TTI의 양 경계에 위치한 다중반송파 심볼에 적용하는 추가적인 펄스 성형은 전송 지연을 제약하기 위한 절단(truncation) 또는 TTI 간 다중 접속으로 인한 간섭 완화 등을 위해 사용될 수 있다. 이러한 추가적인 과정들을 복조 파형

에 포함시켜 표현할 수도 있다.

Before multicarrier demodulation of the th multicarrier symbol, additional wideband/subband filtering and/or additional pulse shaping may be added to the multicarrier symbol located at both boundaries of the TTI. Full-band filtering may be used for mitigation of out-of-band emission (OOBE), and the like. Subband filtering may be used not only for mitigating out-of-band emission but also for mitigating interference between subbands or subband groups when performing multiple access and/or numerology multiplexing on a subband or subband group basis. Additional pulse shaping applied to multi-carrier symbols located at both boundaries of the TTI may be used for truncation to limit transmission delay or to mitigate interference due to multiple access between TTIs. These additional processes are combined with the demodulation waveform.

It can also be expressed by including

번째 2차원 자원으로의 복조 파형

을 아래 수학식 16과 같이 특수 경우로써 표현할 수 있다.on the second two-dimensional domain above for each of the existing modulation schemes.

Demodulation waveform to the second 2D resource

can be expressed as a special case as in Equation 16 below.

(2) Demapping of symbols demodulated from resources on the second two-dimensional domain (operation of the first demapper 220)

번째 2차원 자원에 복조된 심볼을

번째 스프레딩된 심볼로 디매핑하는 디매퍼

를 아래 수학식 17과 같이 표현할 수 있다.The first demapper 220 may demap the demodulated symbols to the resources on the second 2D domain. on the second two-dimensional domain

The demodulated symbol is added to the second 2D resource.

Demapper to demap to the second spread symbol

can be expressed as Equation 17 below.

의 일 예를 아래 수학식 18과 같이 들 수 있다.the demapper

An example of can be given as in Equation 18 below.

로부터 상기 디매퍼

에 따라 디매핑된 심볼들로 구성된 벡터

를 아래 수학식 19와 같이 표현할 수 있다.The above demodulated symbol matrix

from the demapper

vector of symbols demapped according to

can be expressed as Equation 19 below.

(3) Second 2D domain channel estimation and channel equalization thereof (Operation of first channel equalizer 230) for demated demodulated symbols

After demodulation (if necessary), channel estimation for second 2D domain channel equalization of demulated symbols and channel equalization thereof may be performed according to Equation (20).

(4) Post-processing (operation of post-processing unit 240 ) for despreading symbols demapping (or channel equalizing after demapping) to resources on the first 2D domain

번째 자원들에 매핑된 데이터 심볼

는 제1 2차원 도메인 상의

번째 자원으로 디스프레딩 시키기 위한 후처리 벡터

와 제2 2차원 도메인 상의 자원들로부터 디매핑된(또는 디매핑 후 제2 2차원 도메인 채널 등화를 거친) 심볼 벡터

를 내적시켜 아래 수학식 21과 같이 구할 수 있다.The post-processing unit 240 is a data symbol mapped to resources on the first 2D domain for symbols demapped from resources on the second 2D domain (or subjected to second 2D domain channel equalization after demapping). Post-processing can be performed to despread to on the first two-dimensional domain

data symbols mapped to the second resources

is on the first two-dimensional domain

Post-processing vector for despreading to the second resource

and a symbol vector demapped from resources on the second two-dimensional domain (or subjected to second two-dimensional domain channel equalization after demapping).

can be obtained as in Equation 21 below.

번째 2차원 자원으로 디스프레딩 시키기 위한 후처리 벡터

를 아래 수학식 22와 같이 특수 경우로써 표현할 수 있다.on the first two-dimensional domain for each of the existing demodulation schemes.

Post-processing vector for despreading to the second 2D resource

can be expressed as a special case as in Equation 22 below.

(5) Demapping of post-processed data symbols from resources on the first two-dimensional domain (operation of the second demapper 250 )

번째 2차원 자원으로부터

번째 사용자의

번째 데이터 심볼로 매핑하는

번째 사용자를 위한 디매퍼(demapper)

를 아래 수학식 23과 같이 표현할 수 있다.The second demapper 250 may demap each data symbol of each user from post-processed data symbols mapped to resources on the first 2D domain. on the first two-dimensional domain

from the second 2D resource

second user's

mapping to the second data symbol

A demapper for the second user

can be expressed as in Equation 23 below.

번째 2차원 자원으로부터 디매퍼

에 의해 디매핑된

번째 사용자의 번째 데이터 심볼을 아래 수학식 24와 같이 표현할 수 있다.

Demapper from the second 2D resource

demapped by

The th data symbol of the th user can be expressed as in Equation 24 below.

(6) First two-dimensional domain channel estimation and channel equalization thereof for demapping data symbols after post-processing (operation of second channel equalizer 260)

번째 사용자를 위한 디매핑된 데이터 심볼 벡터

에 대해 채널 등화를 거친 데이터 심볼 벡터

는 아래 수학식 25와 같이 표현할 수 있다.After post-processing (if necessary), channel estimation for the first 2D domain channel equalization of the demapping data symbols and channel equalization thereof may be performed.

Demapped data symbol vector for second user

data symbol vector after channel equalization with respect to

can be expressed as in Equation 25 below.

(7) Spreading/Despreading Matrix and Modulation/Demodulation Waveform Vector Design

,

,

,

에 대한 설계가 요구된다. 2D 스프레딩/디스프레딩의 경우 사각형의 파형을 갖는 2D symplectic transform뿐 아니라 부드러운 windowing을 추가적으로 적용할 수 있다. 또한 시간-주파수 변복조 파형에 대해서는 Gabor system을 기반으로 하여 해당 채널의 통계적 특성에 따라 prototype pulse를 최적화할 수도 있으며, 복수의 시간-주파수 자원 그룹을 고려하는 경우에는 각 시간-주파수 자원 그룹에 시간 그리고/또는 주파수 도메인 상에 bandpass 필터링을 적용할 수도 있으며 서로 다른 numerology에 의한 다중접속, 불완전한 동기, 서로 다른 채널을 갖는 사용자들의 다중접속 등을 반영하여 해당 필터의 최적화를 고려할 수 있다.Robust to channel spread (delay spread, Doppler spread) in the generalized 2D spread multicarrier waveform framework

,

,

,

design is required. In the case of 2D spreading/despreading, soft windowing can be additionally applied as well as 2D symplectic transform having a rectangular waveform. In addition, for the time-frequency modulation/demodulation waveform, the prototype pulse can be optimized according to the statistical characteristics of the corresponding channel based on the Gabor system, and when a plurality of time-frequency resource groups are considered, time and / Alternatively, bandpass filtering may be applied in the frequency domain, and optimization of the filter may be considered by reflecting multiple access by different numerology, incomplete synchronization, and multiple access of users having different channels.

,

,

,

에 대한 설계가 요구된다.In addition, if an ideal channel is assumed and perfect reconstruction of the demodulated data symbol is required, the above-described condition is satisfied as shown in Equation 26 below.

,

,

,

design is required.

Alternatively, preprocessing for orthogonalization may be additionally performed prior to preprocessing for spreading data symbols to resources on the second 2D domain in order to completely restore the demodulated data symbol.

6 is a block diagram illustrating an embodiment of a communication node constituting a communication system.

Referring to FIG. 6 , the communication node 300 may be a transmitter according to an embodiment of the present invention shown in FIG. 1 or a receiver according to an embodiment of the present invention with reference to FIG. 5 . Alternatively, the communication node 300 may be a communication node constituting various other communication systems.

The communication node 300 may include at least one processor 310 , a memory 320 , and a transceiver 330 connected to a network to perform communication. In addition, the communication node 300 may further include an input interface device 340 , an output interface device 350 , a storage device 360 , and the like. Each of the components included in the communication node 300 may be connected by a bus 370 to communicate with each other. However, each of the components included in the communication node 300 may not be connected to the common bus 370 but to the processor 310 through an individual interface or an individual bus. For example, the processor 310 may be connected to at least one of the memory 320 , the transceiver 330 , the input interface device 340 , the output interface device 350 , and the storage device 360 through a dedicated interface. .

The processor 310 may execute a program command stored in at least one of the memory 320 and the storage device 360 . The processor 310 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 320 and the storage device 360 may be configured of at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 320 may include at least one of a read only memory (ROM) and a random access memory (RAM).

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 (1)

mapping the channel coded data symbols to resources on a first two-dimensional domain;
performing preprocessing for spreading data symbols mapped to resources on the first two-dimensional domain to resources on a second two-dimensional domain;
mapping the preprocessed data symbols to resources on the second two-dimensional main; and
modulating data symbols mapped to resources on the second two-dimensional main for each resource on the second two-dimensional main,
A two-dimensional spread multicarrier modulation method.

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