KR102564421B1 - Method and apparatus for generating baseband transmission signal in mobile communication system supporting multiple component carriers - Google Patents

Abstract

A method for generating a baseband signal includes mapping frequency domain data for a plurality of component carriers to subcarrier resources; performing a frequency shift on frequency domain data allocated to the subcarrier resources; generating a time domain signal by performing IFFT on the frequency-shifted frequency domain data using one inverse fast Fourier transform (IFFT) block; and generating a time domain baseband signal by adding a cyclic prefix (CP) to the time domain signal.

Description

Method and apparatus for generating baseband transmission signal in mobile communication system supporting multiple component carriers

The present invention relates to a mobile communication system, and more particularly, converts frequency domain signals of a plurality of component carriers into time domain signals in a mobile communication system supporting multiple component carriers. It relates to a method and apparatus for generating one baseband transmission signal by doing so.

As the spread of mobile communication terminals such as smartphones and tablet PCs is rapidly increasing, the amount of data to be processed by mobile communication base stations is exponentially increasing. commercialized

A typical 5th generation mobile communication system, ^3rd generation partnership project (3GPP) new radio (NR) mobile communication system, can operate in two frequency bands of frequency region 1 (FR1) and frequency region 2 (FR2), and has a plurality of A carrier aggregation technology that supports wideband using frequency blocks is used. The carrier aggregation technology is a technology that supports a wider frequency band by using several frequency blocks as one large logical frequency band. In this case, the bandwidth of each frequency block is defined as a component carrier based on the system bandwidth used in the 5G system.

Meanwhile, in order to use carrier aggregation technology supporting a plurality of component carriers in a 5G mobile communication system, an efficient method for generating baseband signals of a plurality of component carriers is required.

An object of the present invention to solve the above problems is to convert a plurality of frequency domain signals into a time domain signal in a mobile communication system supporting multiple component carriers to form a single baseband signal. ) to provide a method and apparatus for generating a signal.

One embodiment of the present invention for achieving the above object is a method for generating a baseband signal performed in a signal transmission apparatus, mapping frequency domain data for a plurality of component carriers to subcarrier resources. doing; performing a frequency shift on frequency domain data allocated to the subcarrier resources; generating a time domain signal by performing IFFT on the frequency-shifted frequency domain data using one inverse fast Fourier transform (IFFT) block; and generating a time domain baseband signal by adding a cyclic prefix (CP) to the time domain signal.

The plurality of component carriers may be contiguous component carriers in the frequency domain.

When the signal transmission device is a distributed unit (DU), the frequency domain data may be received from a central unit (CU) through a front haul interface.

Each of the plurality of component carriers may have a data transmission band of 95.04 MHz and a guard band of 4.920 MHz.

Each of the plurality of component carriers has a 120 Khz subcarrier spacing (SCS), the data transmission band consists of 792 subcarriers, and the guard band may consist of 41 subcarriers.

In the step of performing the frequency shift, the frequency shift may be performed such that halves of frequency domain data allocated to the subcarrier resources are crossed with each other and input to the IFFT block.

The IFFT block may use a vector input scheme for receiving a plurality of inputs per clock.

The baseband signal generation method includes up-converting or down-converting a frequency of the time-domain baseband signal by 1/2 of a subcarrier interval to align a center frequency of the time-domain baseband signal with a center of a subcarrier. may additionally include.

Another embodiment of the present invention for achieving the above object is an apparatus for generating a baseband signal, comprising: a subcarrier mapping unit for mapping frequency domain data for a plurality of component carriers to subcarrier resources; a frequency shift unit performing a frequency shift on frequency domain data allocated to the subcarrier resources; an IFFT unit generating a time domain signal by performing IFFT on the frequency-shifted frequency domain data using one inverse fast Fourier transform (IFFT) block; and a CP adder generating a time domain baseband signal by adding a cyclic prefix (CP) to the time domain signal.

The plurality of component carriers may be contiguous component carriers in the frequency domain.

When the signal transmission device equipped with the baseband signal generator is a distributed unit (DU), the frequency domain data may be received from a central unit (CU) through a front haul interface.

Each of the plurality of component carriers may have a data transmission band of 95.04 MHz and a guard band of 4.920 MHz.

Each of the plurality of component carriers has a 120 Khz subcarrier spacing (SCS), the data transmission band consists of 792 subcarriers, and the guard band may consist of 41 subcarriers.

The frequency shift unit may perform the frequency shift so that halves of frequency domain data allocated to the subcarrier resources are intersected and input to the IFFT block.

The IFFT block may use a vector input scheme for receiving a plurality of inputs per clock.

The baseband signal generator performs up-converting or down-converting the frequency of the time-domain baseband signal by 1/2 of a subcarrier interval to align the center frequency of the time-domain baseband signal with the center of the subcarrier. A band frequency converter may be further included.

Another embodiment of the present invention for achieving the above object is a distributed unit (DU), a fronthaul interface device for receiving frequency domain data for a plurality of component carriers from a central unit (central unit); a baseband signal generator for converting the frequency domain data for the plurality of component carriers into a time domain baseband signal using one inverse fast Fourier transform (IFFT) block; and a frequency converter converting the time domain baseband signal into an RF signal.

The baseband signal generating apparatus includes a subcarrier mapping unit that maps the frequency domain data to subcarrier resources; a frequency shift unit performing a frequency shift on frequency domain data allocated to the subcarrier resources; an IFFT unit generating a time domain signal by performing IFFT on the frequency-domain data frequency-shifted by the frequency shift unit using the one IFFT block; and a CP adder generating a time domain baseband signal by adding a cyclic prefix (CP) to the time domain signal.

The plurality of component carriers may be contiguous component carriers in the frequency domain.

The baseband signal generating apparatus up-converts or down-converts a frequency of the time-domain baseband signal by 1/2 of a subcarrier interval to align a center frequency of the time-domain baseband signal with a center of a subcarrier. A baseband frequency converter may be further included.

An embodiment of the present invention provides an efficient method of generating a single baseband signal by converting a plurality of frequency domain signals into time domain signals in a mobile communication system supporting multiple component carriers. Unlike the conventional technology, since a plurality of frequency domain signals are directly converted into time domain signals using only a single IFFT block, separate time domain signals output from IFFT blocks individually present in each component carrier are multiplied by a frequency offset. It has the advantage that no circuit configuration is required.

1 is a conceptual diagram for explaining a process of generating a baseband signal in a mobile communication system to which carrier aggregation technology is applied.
2 is a conceptual diagram illustrating a baseband signal generation method and apparatus for a case where carrier aggregation is applied in a mobile communication system according to an embodiment of the present invention.
3 is a table for explaining the configuration of a component carrier according to an embodiment of the present invention.
4 is a conceptual diagram for explaining arrangement of 8 component carriers in a frequency domain in a method and apparatus for generating a baseband signal according to an embodiment of the present invention.
5 is a conceptual diagram illustrating two adjacent component carriers located at a center frequency.
6 is a table for explaining allocation of subcarrier indices to component carriers according to an embodiment of the present invention.
7 is a conceptual diagram for explaining the role of an FFT shift block according to an embodiment of the present invention.
8 is a table for explaining data throughput required by an IFFT unit according to an embodiment of the present invention.
9 is a conceptual diagram for explaining the operation of a CP adder according to an embodiment of the present invention.
10 is a block diagram showing the configuration of a distribution unit (DU) to which a baseband signal generating apparatus according to an embodiment of the present invention is applied.

Since the present invention can make various changes and have various embodiments, specific embodiments will be 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 should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. Like reference numerals have been used for like elements throughout the description of each figure.

Terms such as first, second, A, and B may be used to describe various components, but the components should not be limited by the terms. These terms are only used for the purpose of distinguishing one component from another. For example, a first element may be termed a second element, and similarly, a second element may be termed a first element, without departing from the scope of the present invention. The term “and/or” includes any combination of a plurality of related listed items or any of a plurality of related listed items.

It is understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, but other elements may exist in the middle. It should be. On the other hand, when an element is referred to as “directly connected” or “directly connected” to another element, it should be understood that no other element exists in the middle.

Terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "include" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

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 the present 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 unless explicitly defined in the present application, they should not be interpreted in an ideal or excessively formal meaning. don't

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

Embodiments of the present invention are baseband performed in a distributed unit (DU) connected through a fronthaul interface to a base station central unit (CU) installed in a station in a 5G mobile communication base station system. ) Provides a signal generation method and a device that performs the method.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. However, embodiments of the present invention may be implemented in many different forms and are not limited to the embodiments described herein.

1 is a conceptual diagram for explaining a process of generating a baseband signal in a mobile communication system to which carrier aggregation technology is applied.

Referring to FIG. 1, a process of generating a baseband signal in a mobile communication system to which a carrier aggregation technology that aggregates and uses 8 component carriers is applied is shown.

In FIG. 1, signals transmitted through component carriers may be converted into modulation symbols by modulators 111 to 118 and then output. Modulation symbols of each component carrier may be mapped to subcarriers by each subcarrier mapper 121 to 128. At this time, each of the subcarrier mappers 121 to 128 modifies the indexes of the mapped subcarriers to correspond to the input signals of the corresponding inverse fast Fourier transform (IFFT) blocks 131 to 138, so that the corresponding IFFT blocks 131 ~138).

For example, in each subcarrier mapper, a frequency shift is applied to subcarrier indices 0 to 1023 corresponding to 1024 subcarriers to change the positions of subcarrier indices 512 to 1023 and subcarrier indices 0 to 511. It is input to each IFFT block. That is, halves of modulation symbols corresponding to 1024 subcarriers are crossed with each other and input to the IFFT block.

Each of the IFT blocks 131 to 138 may output a time domain signal corresponding to each component carrier by performing IFFT on input modulation symbols. Thereafter, the time domain signal output from each IFFT block may be multiplied by a frequency offset corresponding to each component carrier by the frequency offset applying units 141 to 148 corresponding to each component carrier. Thereafter, the time domain signals of the component carriers multiplied by the frequency offset are summed to generate a carrier-aggregated baseband signal, and the baseband signal carrier-aggregated by the CP adder 150 receives a cyclic prefix (CP) may be added.

As described above, according to the prior art, when 8 component carriers are aggregated, 8 IFFT blocks are required, and a circuit for multiplying a time domain signal output from each IFFT block by a frequency offset corresponding to each component carrier configuration is required. In particular, since the frequency offset application units 141 to 148 that multiply the frequency offset in the time domain must be operated with a corresponding high operating clock at a high sample rate of IFFT blocks, complexity and cost of the circuit increase. there is

2 is a conceptual diagram illustrating a baseband signal generation method and apparatus for a case where carrier aggregation is applied in a mobile communication system according to an embodiment of the present invention.

The baseband generation method and apparatus described with reference to FIG. 2 can be used in an open base station distributed unit, but also in a general base station that does not have a CU-DU structure (ie, a structure to which function-splitting is applied) can be used Hereinafter, a DU or a general base station to which the method and apparatus for generating a baseband signal are applied is collectively referred to as a 'signal transmission apparatus'.

For convenience of description, an embodiment described below assumes a signal transmission apparatus using 8 component carriers each having a bandwidth of 100 MHz in a 28 GHz band. Also, the 8 component carriers are continuous in the frequency domain. However, various embodiments of the present invention can be easily modified and applied to a system operating in a band other than the 28 GHz band. In addition, various embodiments of the present invention can be easily modified for component carriers having bandwidths other than the 100 MHz band. and can be applied.

Referring to FIG. 2 , the baseband signal generating apparatus 200 may receive modulated frequency domain data 201 corresponding to 8 component carriers. The frequency domain data may be generated by a signal transmitting device (eg, a base station) including the baseband signal generating device. Alternatively, when the signal transmission device including the baseband signal generator is a distribution unit (DU), the signal transmission device transmits modulated frequency domain data corresponding to 8 component carriers through a fronthaul interface to a CU (not shown) can be received from In this case, the frequency domain data corresponding to each component carrier may be composed of frequency domain complex data (ie, complex modulation symbols) having a 100 MHz bandwidth including a guard band according to the 5G NR standard.

The subcarrier mapping unit 210 according to an embodiment of the present invention may map frequency domain data corresponding to 8 component carriers to 8192 subcarriers so that they can be input to the IFFT unit 230 to be described later. . That is, the subcarrier mapping unit 210 serves to allocate frequency domain data of 8 component carriers to 8192 subcarrier resources, and fills unused subcarrier resources with '0'. A guard band (GB) exists between each component carrier, and the guard band can be implemented by filling '0' into corresponding subcarrier resources.

The frequency shift unit 220 shifts indices of subcarriers mapped to subcarrier resources to correspond to inputs of the IFFT unit 230 and inputs them to the IFFT unit 240. For example, the frequency shift unit 220 applies a frequency shift to indices 0 to 8195 corresponding to 8196 subcarriers to change the positions of subcarrier indices 4096 to 8191 and subcarrier indices 0 to 4095 to obtain IFFT unit 240 ) is entered. That is, halves of frequency domain data allocated to the subcarrier resources may be intersected and input to the IFFT unit 230 . At this time, the IFFT unit 230 may be composed of a single IFFT block.

The CP adding unit 240 may add a CP to the time domain signal output from the IFFT unit 230 to finally generate a time domain baseband signal. That is, the CP adder 240 copies a certain area at the end of the time domain signal output from the IFFT unit 230 and adds it to the first part of the signal to finally obtain a time domain corresponding to one OFDM symbol. A baseband signal can be generated.

Meanwhile, the baseband signal generator 200 according to an embodiment of the present invention may further include a baseband frequency converter 250. The baseband frequency converter 250 raises the frequency of the time-domain baseband signal by 1/2 of the subcarrier interval in order to align the center frequency of the generated time-domain baseband signal to the center of the subcarrier. It is a component for converting or down-converting. The baseband frequency converter 250 will be described later.

When using the method and apparatus for generating a baseband signal according to an embodiment of the present invention, frequency domain data corresponding to eight component carriers is integrated into one time domain by the IFFT unit 230 using only one IFFT block. can be converted directly into a signal. Comparing the baseband signal generation method and apparatus illustrated in FIG. 2 with the example described in FIG. 1, the 8 IFFT blocks 131 to 138 can be replaced with the IFFT unit 230 composed of only one IFFT block. There is an advantage in that the frequency offset application unit 141 to 148 for multiplying the frequency offset to the time domain signal output from each of the IFFT blocks 131 to 138 is not required.

3 is a table for explaining the configuration of a component carrier according to an embodiment of the present invention.

Referring to FIG. 3, the subcarrier spacing (SCS) of each component carrier according to an embodiment of the present invention is configured to 120 KHz, and a sampling rate of 122.88 MHz is used. Since a total of 66 resource blocks (RBs) are used for data transmission, a total of 792 (=12*66) subcarriers are used for data transmission, and the corresponding frequency bandwidth is 95.040 MHz. Accordingly, when a guard band is included, a bandwidth of about 100 MHz per component carrier is used.

4 is a conceptual diagram for explaining arrangement of 8 component carriers in a frequency domain in a method and apparatus for generating a baseband signal according to an embodiment of the present invention.

In a system using the 28 GHz band, since 8192 point IFFT blocks are used to support 8 component carriers each having a bandwidth of 100 MHz, there are 8192 subcarrier resources.

In the NR system, the nominal channel spacing between component carriers in the adjacent 100 MHz band for intra-band contiguously aggregated carriers in the 28 GHz band is expressed by the following formula according to the 3GPP 38.104 standard 1 is defined as

From here, class is the base station channel bandwidth of 100 MHz, is 3 corresponding to 120 KHz SCS, is 2,420 KHz as a minimum guard band.

According to the calculation result using Equation 1 above, the nominal channel interval is 99.96 MHz, and is composed of a data transmission band of 95.04 MHz and a guard band of 4.920 MHz.

Hereinafter, the configuration of the above-described subcarrier mapping unit 210 and the role of the baseband frequency converter 250 will be described.

5 is a conceptual diagram illustrating two adjacent component carriers located at a center frequency.

Referring to FIG. 5, the frequency interval between the two component carriers is larger than the minimum guard band and nominal channel interval in units of 120 KHz corresponding to the least common multiple of 60 KHz, which is a channel raster, and 120 KHz, which is a subcarrier interval. (nominal channel spacing) may be set to a smaller value. In the case of a 28 GHz band system, a guard band of 4,920 kHz may be set as shown in FIG. 5, and 4,920 KHz may correspond to 41 subcarriers. Accordingly, the subcarrier mapping unit 210 may be implemented as a fixed mapping.

On the other hand, since the center frequency must be aligned to the center of the subcarrier, the mapped subcarriers are shifted to the right (to a lower frequency) or to the left by 1/2 of the subcarrier spacing (i.e., 60 KHz) rather than the center of the entire RF band. It should be shifted (shifted to a higher frequency). This movement direction may be fixed at the design stage. Therefore, in the baseband signal generation method and apparatus according to an embodiment of the present invention, the frequency of the time-domain baseband signal output from the CP adder 240 is increased by 60 kHz using the baseband frequency converter 250. You can either up-convert or down-convert.

Therefore, in order to easily align the center frequency to the center of the subcarrier, in an embodiment of the present invention, 20 (ie, 2420 kHz) out of a total of 41 guard band subcarriers are set to the left (or right) of the center frequency. , and 21 of a total of 41 guard band subcarriers (ie, 2540 kHz) can be located to the right (or left) of the center frequency. That is, when 20 of the 41 guard band subcarriers are located to the left of the center frequency, the time domain baseband signal output from the CP adder 240 is converted to the left (lower frequency) by the baseband frequency converter 250. side) is shifted to 60Khz. On the other hand, that is, when 20 of the 41 guard band subcarriers are located to the right of the center frequency, the time domain baseband signal output from the CP adder 240 is converted to the right (right) by the baseband frequency converting unit 250. 60Khz is shifted to the higher frequency side).

6 is a table for explaining allocation of subcarrier indices to component carriers according to an embodiment of the present invention.

Referring to FIG. 6, when the frequency interval for each component carrier in a 100 MHz bandwidth is 99.960 MHz and the center frequency is moved to the left by 60 KHz, a correspondence between a subcarrier index and an IFFT input index is explained. In the above example, when the frequency interval for each component carrier is 99.960 MHz, a transmission bandwidth of 95.040 MHz and a guard band of 4.920 MHz are configured. 95.040 MHz is composed of 792 subcarriers, and 4.840 MHz may be composed of 41 subcarriers.

Hereinafter, the above-described frequency shift unit 220 will be described in detail.

7 is a conceptual diagram for explaining the role of an FFT shift block according to an embodiment of the present invention.

As described above, the subcarrier indices are sequentially listed in frequency order from 0 to 8191, and the frequency shift unit 220 divides the subcarrier indices 0 to 8191 in half and performs frequency shift so as to intersect the IFFT unit 230. will be entered into That is, the frequency shift unit 220 inputs halves of the frequency domain data allocated to the subcarrier resources to the IFFT block constituting the IFFT unit 230 to cross each other.

The frequency shift unit 220 generates input data suitable for the IFFT unit 230 by shifting a zero frequency component (direct current (DC) component) to the center of the spectrum. For example, an operation of the frequency shift unit 220 for an 8192-point IFFT block used in a signal transmission apparatus of a 28 GHz band system can be expressed by the following pseudocode.

If (subcarrier index < 4096) then

FFT input index = subcarrier index + 4096;

Else

FFT input index = subcarrier index - 4096;

Meanwhile, the IFFT unit 230 may use various types of architectures to optimize throughput or area. For example, the required throughput can be achieved using an IFFT architecture supporting vector input data, which is an optimization architecture to achieve giga samples per second (Gsps) class throughput.

8 is a table for explaining data throughput required by an IFFT unit according to an embodiment of the present invention.

Referring to FIG. 8, when an IFFT block exists for each 100 MHz component carrier, a 1024-point IFFT block must be used for a subcarrier interval of 120 kHz. In addition, in order to process the sampling clock of 122.88 MHz, the IFFT block must also operate with an operating clock of 122.88 MHz.

Therefore, in order to process the 800MHz frequency band corresponding to 8 component carriers, a sampling clock of 983.04 MHz is required, and the IFFT unit 230 using a single 8192 point IFFT block must also operate with an operating clock of 983.04 MHz. . Since such a high operating speed cannot be realized in FPGA (field programmable gate array), in order to lower the operating clock, IFFT is performed with an operating clock of 122.88 MHz based on a vector input method that simultaneously inputs 8 inputs per clock. Data can be processed at a rate of 983.04 Msps (mega samples per second).

Hereinafter, the above-described CP adder 240 will be described in detail.

Finally, OFDM symbol data converted from the frequency domain to the time domain using 8192-point IFFT may consist of 8192 data samples.

9 is a conceptual diagram for explaining the operation of a CP adder according to an embodiment of the present invention.

In the NR system, when 120 kHz SCS is applied, 4 slots exist every 0.5 ms, and each slot may consist of 14 symbols. Each of all symbols except the first symbol of 0.5 ms has 8768 samples including 576 CP samples and 8192 data samples, and the first symbol of 0.5 ms consists of 1088 CP samples and 8192 data samples, resulting in 9280 can have samples.

Referring to FIG. 10, for the first symbol of 0.5 ms, the CP addition block can generate a symbol having a total of 9280 samples by copying the latter 1088 samples of 8192 IFFT output samples and appending them to the front part. In addition, for each of the symbols except for the first symbol of 0.5 ms, the CP addition block can generate a symbol having a total of 8768 samples by appending 576 samples in the second half of 8192 IFFT output samples to the front part.

10 is a block diagram showing the configuration of a distribution unit (DU) to which a baseband signal generating apparatus according to an embodiment of the present invention is applied.

Referring to FIG. 10, a DU 1000 according to an embodiment of the present invention includes a fronthaul interface device 1010 receiving frequency domain data for a plurality of component carriers from a central unit (CU), the plurality of component carriers a baseband signal generating device 1020 that converts frequency domain data for IFFT into a time domain baseband signal using one single IFFT block; and a frequency converter 1030 converting the time domain baseband signal into an RF signal.

A DU according to an embodiment of the present invention may be implemented as an O-RAN distributed unit (O-DU) according to an open radio access network alliance (O-RAN Alliance) standard. In addition, a CU connected to the DU through a fronthaul interface may be implemented as an O-RAN central unit (O-CU). In this case, the fronthaul interface device may be configured as an interface device conforming to the O-RAN fronthaul standard.

The baseband signal generator 1020 corresponds to the baseband signal generator 200 described with reference to FIG. 2 . That is, the baseband signal generator 1020 may include a subcarrier mapping unit 210, a frequency shifting unit 220, an IFFT unit 230, and a CP adding unit 240. In addition, the baseband signal generator 1020 may further include a baseband frequency converter 250 .

Meanwhile, the above-described baseband signal generator 1020 may include at least one processor and a memory storing instructions executed by the at least one processor. In this case, the subcarrier mapping unit 210, the frequency shifting unit 220, the IFFT unit 230, and the CP adding unit 240 may be composed of program codes implemented by the instructions. Alternatively, some of the subcarrier mapping unit 210, frequency shifting unit 220, IFFT unit 230, and CP adding unit 240 are configured with dedicated logic circuits, and the remaining parts are implemented by the instructions It can be composed of program code that becomes.

Finally, the frequency converter 1030 is a device that converts the time domain baseband signal generated by the baseband signal generator 1020 into an RF signal. The RF signal may be transmitted through an amplification unit and an antenna.

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 on a computer readable medium. Computer readable media may include program instructions, data files, data structures, etc. alone or in combination. Program instructions recorded on a computer readable medium may be specially designed and configured for the present invention or may be known and usable to those skilled in computer software.

Examples of computer readable media include hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include high-level language codes that can be executed by a computer using an interpreter or the like as well as machine language codes generated by a compiler. The hardware device described above may be configured to operate with at least one software module to perform the operations of the present invention, and vice versa.

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

Claims (20)

A method for generating a baseband signal, performed in a signal transmission apparatus, comprising:
mapping frequency domain data for a plurality of component carriers to subcarrier resources;
performing a frequency shift on frequency domain data allocated to the subcarrier resources;
generating a time domain signal by performing IFFT on the frequency-shifted frequency domain data using one inverse fast Fourier transform (IFFT) block; and
generating a time domain baseband signal by adding a cyclic prefix (CP) to the time domain signal;
Up-converting or down-converting the frequency of the time-domain baseband signal by half a subcarrier interval to align the center frequency of the time-domain baseband signal to the center of the subcarrier.
A method for generating baseband signals. The method of claim 1,
The plurality of component carriers are contiguous component carriers in the frequency domain,
A method for generating baseband signals. The method of claim 1,
When the signal transmission device is a distributed unit (DU), the frequency domain data is received from a central unit (CU) through a front haul interface,
A method for generating baseband signals. The method of claim 1,
Each of the plurality of component carriers has a data transmission band of 95.04 MHz and a guard band of 4.920 MHz,
A method for generating baseband signals. The method of claim 4,
Each of the plurality of component carriers has a 120 Khz subcarrier spacing (SCS), the data transmission band consists of 792 subcarriers, and the guard band consists of 41 subcarriers,
A method for generating baseband signals. The method of claim 1,
In the step of performing the frequency shift, the frequency shift is performed such that halves of the frequency domain data allocated to the subcarrier resources are intersected and input to the IFFT block.
A method for generating baseband signals. The method of claim 1,
The IFFT block uses a vector input scheme that receives multiple inputs per clock.
A method for generating baseband signals. delete As a baseband signal generator,
a subcarrier mapping unit that maps frequency domain data for a plurality of component carriers to subcarrier resources;
a frequency shift unit performing a frequency shift on frequency domain data allocated to the subcarrier resources;
an IFFT unit generating a time domain signal by performing IFFT on the frequency-shifted frequency domain data using one inverse fast Fourier transform (IFFT) block; and
a CP adder for generating a time domain baseband signal by adding a cyclic prefix (CP) to the time domain signal;
Further comprising a baseband frequency converter configured to up-convert or down-convert the frequency of the time-domain baseband signal by 1/2 of a subcarrier interval to align the center frequency of the time-domain baseband signal to the center of the subcarrier. doing,
A baseband signal generator. The method of claim 9,
The plurality of component carriers are contiguous component carriers in the frequency domain,
A baseband signal generator. The method of claim 9,
When the signal transmission device equipped with the baseband signal generator is a distributed unit (DU), the frequency domain data is received from a central unit (CU) through a front haul interface,
A baseband signal generator. The method of claim 9,
Each of the plurality of component carriers has a data transmission band of 95.04 MHz and a guard band of 4.920 MHz,
A baseband signal generator. The method of claim 12,
Each of the plurality of component carriers has a 120 Khz subcarrier spacing (SCS), the data transmission band consists of 792 subcarriers, and the guard band consists of 41 subcarriers,
A baseband signal generator. The method of claim 9,
The frequency shift unit performs the frequency shift such that half of the frequency domain data allocated to the subcarrier resources are intersected with each other and input to the IFFT block.
A baseband signal generator. The method of claim 9,
The IFFT block uses a vector input scheme that receives multiple inputs per clock.
A baseband signal generator. delete As a distributed unit (DU),
a fronthaul interface device receiving frequency domain data for a plurality of component carriers from a central unit;
a baseband signal generator for converting the frequency domain data for the plurality of component carriers into a time domain baseband signal using one inverse fast Fourier transform (IFFT) block; and
a frequency converter converting the time domain baseband signal into an RF signal;
The baseband signal generating apparatus up-converts or down-converts a frequency of the time-domain baseband signal by 1/2 of a subcarrier interval to align a center frequency of the time-domain baseband signal with a center of a subcarrier. Further comprising a baseband frequency converter,
distributed unit. The method of claim 17
The baseband signal generator
a subcarrier mapping unit to map the frequency domain data to subcarrier resources;
a frequency shift unit performing a frequency shift on frequency domain data allocated to the subcarrier resources;
an IFFT unit generating a time domain signal by performing IFFT on the frequency-domain data frequency-shifted by the frequency shift unit using the one IFFT block; and
And a CP adder for generating a time domain baseband signal by adding a cyclic prefix (CP) to the time domain signal.
distributed unit. The method of claim 17
The plurality of component carriers are contiguous component carriers in the frequency domain,
distributed unit. delete

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