KR102581264B1 - Apparatus and method for minimizing interference between adjacent bands havnig differenct subcarrier interval with each other - Google Patents

Abstract

In a mobile communication system supporting frequency division multiplexing (FDM) according to an embodiment of the present invention, a wireless signal is transmitted using a plurality of subcarriers belonging to a frequency region defined on the frequency axis. For a signal transmission end, an apparatus for minimizing interference between subcarriers divides the frequency domain into a plurality of frequency bands and arranges each of the subcarriers at different positions on the frequency axis within the frequency band, wherein the frequency band is divided into a plurality of frequency bands. Each band includes at least two of the subcarriers, and power is allocated to each of the subcarriers and a subcarrier arrangement unit such that the frequency spacing between adjacent subcarriers within each of the frequency bands is equal to the interwave spacing determined for each frequency band, When two subcarriers adjacent to each other on the frequency axis among the subcarriers belong to different frequency bands among the frequency bands, a power allocation unit that allocates higher power to the subcarrier belonging to a frequency band with a smaller interwave spacing among the two adjacent subcarriers. It can be included.

Description

Apparatus and method for minimizing interference between adjacent bands having different subcarrier spacing {APPARATUS AND METHOD FOR MINIMIZING INTERFERENCE BETWEEN ADJACENT BANDS HAVNIG DIFFERENCT SUBCARRIER INTERVAL WITH EACH OTHER}

The present invention provides, in a mobile communication system supporting frequency division multiplexing (FDM), an apparatus for minimizing interference caused by uneven spacing between a plurality of subcarriers defined within the frequency band of the system, and It's about method.

Currently, orthogonal frequency division multiple access (OFDMA) technology is being researched and utilized in mobile communication systems. According to OFDMA technology, each user is assigned a certain frequency band, and data is transmitted and received using a plurality of subcarriers defined in the assigned frequency band. In addition, according to OFDMA technology, the spacing between subcarriers (i.e., the frequency difference between adjacent subcarriers) is maintained constant throughout the entire frequency band, and the number of subcarriers can be adjusted according to user needs.

Meanwhile, in communication scenarios using 5G (fifth-generation), the next-generation mobile communication standard, the application of OFDMA technology and f-OFDMA (filtered-OFDMA) technology to the millimeter wave band of 60 GHz or higher is being discussed. While this high frequency band can provide a relatively wide band, the channel environment changes greatly, and therefore the degree or form of interference experienced by each subcarrier varies depending on the channel environment. In a situation where the spacing between subcarriers is fixed throughout the frequency band according to the existing method, it is difficult to control interference caused by different channel environments. Accordingly, research has recently been conducted to transmit data by diversifying the spacing between subcarriers existing within the frequency band.

However, if bands with different spacing between subcarriers coexist within a certain frequency region, inter-band interference (IBI), which did not exist previously, exists. Figure 1 is a diagram showing inter-band interference when adjacent frequency bands have different subcarrier spacing. If adjacent bands have the same subcarrier spacing as in the existing method, zero crossing occurs between signals emitted outside the band, so interference does not occur in adjacent bands, and only Doppler shift (Doppler shift) caused by the channel environment occurs. Doppler shift is the only problem. On the other hand, if adjacent bands have different subcarrier spacing, interference between adjacent bands that did not exist previously occurs, as shown in FIG. 1.

Korea Patent Publication, No. 10-2009-0082689 (published on July 31, 2009)

The problem to be solved by the present invention is to provide an apparatus and method that can minimize inter-band interference when bands with different subcarrier spacing coexist within a certain frequency region in a mobile communication system supporting frequency division multiplexing. .

In a mobile communication system supporting frequency division multiplexing (FDM) according to an embodiment of the present invention, a wireless signal is transmitted using a plurality of subcarriers belonging to a frequency region defined on the frequency axis. For a signal transmission end, an apparatus for minimizing interference between subcarriers divides the frequency domain into a plurality of frequency bands and arranges each of the subcarriers at different positions on the frequency axis within the frequency band, wherein the frequency band is divided into a plurality of frequency bands. Each band includes at least two of the subcarriers, and power is allocated to each of the subcarriers and a subcarrier arrangement unit such that the frequency spacing between adjacent subcarriers within each of the frequency bands is equal to the interwave spacing determined for each frequency band, When two subcarriers adjacent to each other on the frequency axis among the subcarriers belong to different frequency bands among the frequency bands, a power allocation unit that allocates higher power to the subcarrier belonging to a frequency band with a smaller interwave spacing among the two adjacent subcarriers. It can be included.

In a mobile communication system supporting frequency division multiplexing according to an embodiment of the present invention, for a signal transmission terminal for transmitting a wireless signal using a plurality of subcarriers belonging to a frequency region defined on the frequency axis, interference between the subcarriers A method for minimizing is to divide the frequency domain into a plurality of frequency bands and arrange each of the subcarriers at a different position on the frequency axis within the frequency band, wherein each of the frequency bands includes at least two of the subcarriers. A first step of ensuring that the frequency spacing between adjacent subcarriers within each of the frequency bands is equal to the interwave spacing determined for each frequency band, and allocating power to each of the subcarriers, wherein two of the subcarriers are adjacent to each other on the frequency axis. When the subcarriers belong to different frequency bands among the frequency bands, a second step of allocating higher power to the subcarrier belonging to a frequency band with a smaller interwave spacing among the two adjacent subcarriers may be included.

According to an embodiment of the present invention, in a mobile communication system supporting frequency division multiplexing, when a plurality of bands with different subcarrier spacings coexist within a certain frequency region, the arrangement method on the frequency axis of each band and the Inter-band interference can be minimized by adjusting the power allocation method for the subcarriers involved. Accordingly, the reliability and efficiency of data transmission through a mobile communication system can be greatly improved.

Figure 1 is a diagram showing inter-band interference when adjacent frequency bands have different subcarrier spacing.
Figures 2a and 2b are diagrams showing a situation in which frequency bands with different subcarrier spacing exist in the frequency domain.
Figure 3 is a diagram schematically showing the configuration of an interference minimization device according to an embodiment of the present invention.
4A to 4F are diagrams illustrating various application examples of an interference minimization method performed by an interference minimization apparatus according to an embodiment of the present invention.
Figure 5 is a diagram illustrating the sequence of an interference minimization method performed by an interference minimization apparatus according to an embodiment of the present invention.
Figure 6 is a diagram illustrating a specific application example of an interference minimization method performed by an interference minimization device according to an embodiment of the present invention.

The advantages and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and may be implemented in various different forms. The present embodiments are merely provided to ensure that the disclosure of the present invention is complete and to be understood by those skilled in the art. It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims.

In describing embodiments of the present invention, if a detailed description of a known function or configuration is judged to unnecessarily obscure the gist of the present invention, the detailed description will be omitted. The terms described below are terms defined in consideration of functions in the embodiments of the present invention, and may vary depending on the intention or custom of the user or operator. Therefore, the definition should be made based on the contents throughout this specification.

Below, the technical background related to the core features of the present invention will first be described, and then the configuration and operation of the present invention will be described in detail with reference to the drawings.

Figures 2a and 2b are diagrams showing a situation in which frequency bands with different subcarrier spacing exist in the frequency domain. Figure 2a shows that a plurality of frequency bands coexist within a certain frequency area allocated for a mobile communication system according to an embodiment of the present invention. In other words, the frequency domain can be viewed as being divided into a plurality of frequency bands. At this time, the subcarrier spacing of the pth band among the frequency bands arranged on the frequency axis is f _p It is expressed as, and the number of subcarriers in the p-th band is N _p It is expressed as The size of the frequency band, that is, the bandwidth, can be expressed as the number of subcarriers belonging to the frequency band and the spacing between subcarriers, so BW _p When is the bandwidth of the pth band, BW _p = f _p × N _p It can be expressed as Meanwhile, in the present invention, it is preferable to assume that the subcarrier spacing of each band is an integer multiple of the subcarrier spacing of the reference band. For example, if the smallest subcarrier spacing of a certain band is 15kHz, using that band as a standard, the subcarrier spacing of other bands can be 15kHz, 30kHz, 45kHz, etc.

Figure 2b shows the time axis signal of each band when a plurality of frequency bands coexist in a specific frequency region as shown in Figure 2a. T _p means the OFDM (orthogonal frequency division multiplexing) symbol period of the p-th signal. Here, the signal that exists in the section where t<0 on the time axis corresponds to the cyclic prefix (CP), which is a guard section. At this time, the signal on the time axis of the p-th signal can be expressed as Equation 1.

In Equation 1 above, s _n,p means the signal transmitted on the nth subcarrier of the pth signal. h _p (t) refers to the window experienced by the p-th signal. The value of h _p (t) is 0≤t<T _p according to the OFDMA system. When , it is 1 and in the other cases it is 0. Here, T _p is a value determined as the width of the window applied to the p-th signal. f _p (t) is the carrier frequency carrying the pth signal, and assuming no guard band, the gap between carrier frequencies is B _Wp am. Meanwhile, when the receiving end receives the transmission signal as shown in FIG. 2b, the received signal can be expressed as Equation 2 below.

At this time, n(t) is white noise following a complex normal distribution with a standard deviation of σ. Each transmission signal x _p (t) does not overlap because it is transmitted by different carrier waves on the frequency axis, but is transmitted overlapping on the time axis. When transmitted on the time axis in this way, inter-band interference occurs because all signals are combined and transmitted. In the OFDMA system, the received signal in the time domain obtained in this way is converted to the frequency domain to obtain data. Equation 3 below represents inter-band interference coming from another band when the carrier is compensated for the received signal and conversion to the frequency domain is performed.

IBI _l,p represents the inter-band interference experienced by data carried on the l-th subcarrier of the p-th signal. First, the p-th carrier frequency can be compensated for in the received signal, and then converted to the frequency domain to obtain the p-th signal. At this time, IBI _l,p in Equation 3 represents noise from signals other than the p-th signal. As a result, the received signal is a form in which interference and noise are added to the transmitted signal, and can be expressed as Equation 4 below.

where R _{l, p} and IBI _l,p is the inter-band interference between the lth received signal and the pth signal, respectively. Also S _l,p As mentioned in Equation 1 above, means the l-th transmission signal of the p-th signal and becomes the data to be restored. N _l,p is white noise following a complex normal distribution and the standard deviation is σ. At this time, SINR (signal-to-interference and noise ratio, size of interference and noise compared to signal) is defined as Equation 5 below. Equation 5 means the SINR of the l-th data in the p-th signal.

Among interference and noise, interference depends on the environment in which the signal is transmitted and there is no significant change in its characteristics, so it is the size of the transmission power and the size of inter-band interference that can ultimately act as variables for the size of the received power. Ultimately, in order to maximize received power, the size of the allocated power must be maximized while simultaneously minimizing the impact of inter-band interference. Equation 6 is the total sum of SINR presented in Equation 5 above.

In the above equation, Λ _th is the result of adding up the SINR for all data of all signals. In the present invention, Λ _th in Equation 6 The purpose is to maximize the value of, and as a specific method to achieve this goal, in one embodiment of the present invention, a method of determining the arrangement within the frequency domain of each frequency band and a method of determining the arrangement of the subcarriers belonging to each frequency band are provided. It deals with how to allocate power.

In particular, the present invention deals with the case where the subcarrier spacing is 15 kHz or multiples thereof. Referring to FIG. 1 mentioned above, it can be seen that this represents a situation where the subcarrier spacing in one of the two adjacent bands is an integer multiple (2 times) of the subcarrier spacing in the other band. As mentioned earlier, in the case of a multi-carrier system, a sync function is convolutionally calculated with the original signal on the frequency axis during transmission, and the size of the main lobe of the sync function is set to the subcarrier spacing. At this time, as shown in Figure 1, it can be seen that there are parts where zero crossing does not occur in the band with a small subcarrier spacing. That is, when the ratio of the size of the subcarrier spacing of two adjacent bands is an integer multiple, the band with a small subcarrier spacing receives interference from the band with a large subcarrier spacing. On the other hand, bands with large subcarrier spacing do not receive interference from bands with small subcarrier spacing. In conclusion, in a situation where the ratio of the size of the subcarrier spacing of two adjacent bands is an integer multiple, in order to reduce inter-band interference, it is necessary to reduce the power in the band with the large subcarrier spacing and increase the power in the band with the small subcarrier spacing for transmission.

Figure 3 is a diagram schematically showing the configuration of an interference minimization device according to an embodiment of the present invention. The interference minimization device 100 of FIG. 3 is a device for achieving the purpose of the present invention as described above, and allows multiple bands with different subcarrier spacing to coexist within the frequency domain of a mobile communication system supporting frequency division multiplexing. In this case, the function of adjusting the arrangement method on the frequency axis of each band and the power allocation method for subcarriers belonging to each band can be performed. Accordingly, the interference minimization device 100 may target a signal transmission end such as a base station or terminal of a mobile communication system. The interference minimization device 100 of FIG. 3 may include an interface unit 110, a subcarrier arrangement unit 120, a power allocation unit 130, and a storage unit 140. However, since the components of the interference minimization device 100 of FIG. 3 are only one embodiment of the present invention, the technical idea of the present invention is not limited by FIG. 3.

The interface unit 110 may exchange information between the interference minimization device 100 and other components, such as a transmitter in a mobile communication system supporting frequency division multiplexing. For example, the interface unit 110 may obtain the information necessary for the interference minimization device 100 to perform its function from outside the interference minimization device 100, and the band arrangement method determined by the interference minimization device 100 and The power allocation method, etc. can also be transmitted to the transmitting end of the mobile communication system. This interface unit 110 may be implemented through a communication module or data bus.

The subcarrier arrangement unit 120 may divide a given frequency region into a plurality of frequency bands and arrange the subcarriers on the frequency axis so that each frequency band includes at least two subcarriers. The location of the subcarrier on the frequency axis may be the center frequency of the subcarrier, that is, the frequency that is the center of the frequency band occupied by the subcarrier. Here, as described above, the frequency spacing between adjacent subcarriers may be set to be constant within any one frequency band, and this subcarrier spacing may be referred to as “interwave spacing.” The specific method by which the subcarrier placement unit 120 arranges the frequency band and subcarriers will be described later. Meanwhile, the power allocation unit 130 can allocate power to each subcarrier belonging to each band, and specific principles for allocating power will be described later. The subcarrier arrangement unit 120 and the power allocation unit 130 may be implemented by a computing device including a microprocessor.

The storage unit 140 may store information necessary for the interference minimization device 100 based on the control of the subcarrier arrangement unit 120 or the power allocation unit 130. Examples of such necessary information may include, but are not necessarily limited to, the value of the interwave spacing in each band and the number of subcarriers included in each band. This storage unit 140 may be specifically implemented as a computer-readable recording medium. Examples of such computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tapes, CD-ROMs, DVDs, and These include optical media such as optical media, magneto-optical media such as floptical disks, and hardware devices specifically configured to store and execute program instructions, such as flash memory. You can.

4A to 4F are diagrams illustrating various application examples of an interference minimization method performed by an interference minimization apparatus according to an embodiment of the present invention.

Figure 4a is a diagram for explaining a power allocation method when two bands with different interwave spacing are adjacent to each other on the frequency axis. In a situation such as that shown in FIG. 4A, the interference received by a band with a small inter-wave spacing from a band with a large inter-wave spacing is greater than the interference received by a band with a large inter-wave spacing from a band with a small inter-wave spacing. Using this characteristic, when there is a difference in inter-wave spacing between two adjacent bands, high power can be allocated to the band with a small inter-wave spacing, and relatively low power can be allocated to the band with a large inter-wave spacing. Meanwhile, as the difference in the interwave spacing between the two bands increases, the difference in power allocated to the two bands (or the ratio of power allocated) can also increase. Here, allocating high power to a band may mean allocating high power to subcarriers included in the band. According to this, when two subcarriers adjacent to each other on the frequency axis belong to different frequency bands, higher power can be allocated to the subcarrier in a band with a smaller interwave spacing among the two adjacent subcarriers. For example, in the case of (B) in FIG. 4A, the difference in interwave spacing between the two bands is larger than in (A), and accordingly, the difference in power allocated to the two bands is also larger in (B).

Figure 4b is a diagram for explaining a bandwidth allocation method when two bands with different interwave spacing are adjacent. As described above, when two bands are adjacent to each other on the frequency axis, the interference received by the band with a small inter-wave spacing from the band with a large inter-wave spacing is greater than the interference received by the band with a large inter-wave spacing from the band with a small inter-wave spacing. Accordingly, if the number of subcarriers receiving interference is reduced, the overall size of interference can be reduced. Based on this principle, the number of subcarriers in the two bands, which were originally the same as in (A), can be made the same as in (B) by reducing the number of carriers in the band with a small interwave spacing. Meanwhile, in this process, as seen in relation to FIG. 4A, a process of allocating relatively low power to a band with a large interwave spacing may also be additionally performed.

Figure 4c shows a situation where three frequency bands with different interwave spacing coexist within a specific frequency region. As can be seen in Figure 4c, in the case of a band located in the center on the frequency axis, interference is caused to both bands on both sides, so when three bands are adjacent, the amount of interference that the band in the middle gives to the other bands is greater than that of the other two bands. is large, and it also receives the most interference from other bands. In conclusion, the band that causes the least interference, that is, the band with the smallest interwave spacing, can be placed in the central band and assigned relatively high power compared to other adjacent bands. For example, if three bands with subcarrier spacing of 5 kHz, 10 kHz, and 20 kHz are adjacent, the band with the 5 kHz subcarrier spacing that affects the least interference is placed in the middle, and the highest power is allocated to reduce total interference. The amount can be reduced. Extending this principle, if three or more frequency bands coexist and there are two or more frequency bands with a larger inter-wave spacing than the frequency band with the smallest inter-wave spacing, the band with the smallest inter-wave spacing is located at the very edge of the frequency domain. You can avoid doing it. That is, at least one of the other bands can be located on both sides of the band with the smallest interwave spacing.

Figure 4d shows a case where three frequency bands coexist within a specific frequency region, and the interwave spacing of the two bands is the same. When the spacing between subcarriers is the same, zero crossing occurs in all subcarriers, so the two bands do not cause interband interference to each other. On the other hand, if two bands with different inter-wave spacing are adjacent, inter-band interference occurs as described above. In conclusion, when arranging frequency bands, if there are two bands with the same interwave spacing, the bands can be arranged adjacent to each other on the frequency axis. Extending this principle, even when the number of frequency bands is greater than three, bands with the same interwave spacing can be arranged to be adjacent to each other.

Figure 4e is an example of a situation where a plurality of bands coexist within a specific frequency region, and an unused band (a band in which no subcarrier exists) exists among the plurality of bands. In the case of an unused band, it neither causes nor receives interference from other bands, while bands with different interwave spacing interfere with each other. At this time, if an unused band is placed between used bands (bands in which subcarriers exist) on the frequency axis, the size of inter-band interference can be reduced. In other words, the band arrangement method as shown in FIG. 4E is a method to prevent used bands from being arranged adjacent to each other. Accordingly, specifically, the used band and the unused band can be arranged alternately on the frequency axis. This method is especially effective when the interwave spacing of the bands used is different.

Figure 4f is an example showing that in a situation where a plurality of bands coexist within a specific frequency region, power can be allocated differently according to subcarriers even within the same band. First, among the three bands as shown in Figure 4f, the band with the smallest interwave spacing can be placed in the center on the frequency axis, and the remaining two bands can be placed on both sides. At this time, for a band placed in the center, higher power can be allocated to edge subcarriers that are most affected by interference than to the center subcarriers. In contrast, for bands placed on both sides, relatively lower power can be allocated to subcarriers close to the center band than to subcarriers farther from the center band in order to reduce interference in the center band. In this way, the effect of the present invention can be further maximized by allocating different amounts of power to each subcarrier even within one band, taking into account the band arrangement situation.

Figure 5 is a diagram illustrating the sequence of an interference minimization method performed by an interference minimization apparatus according to an embodiment of the present invention. However, since the method shown in FIG. 5 is only an embodiment of the present invention, the spirit of the present invention is not limited by FIG. 5, and each step of the method shown in FIG. 5 is as shown in the drawing in some cases. Of course, it can be performed in a different order.

First, the number of frequency bands for dividing the frequency domain can be set (S110). Next, the subcarrier spacing, that is, the interwave spacing, of each frequency band can be determined (S120). For example, this inter-wave spacing can be determined as an integer multiple of the reference frequency based on 15 kHz or as a multiple of 2 n (n is a natural number) squared (2 times, 4 times, 8 times...), but is not necessarily limited to this. does not Next, the bandwidth for each frequency band can be determined (S130), and the position on the frequency axis (i.e., the arrangement pattern of each frequency band) can be determined (S140). The steps described so far can be performed by the subcarrier arrangement unit 120, and the specific principles for performing the steps are as described with reference to FIGS. 4A to 4F. Based on the steps performed above, each subcarrier can be placed at a position on the frequency axis. Finally, power can be allocated to subcarriers in each frequency band (S150). This step may be performed by the power allocation unit 130, and power may be uniformly allocated to all subcarriers existing in an arbitrary frequency band. However, different power may be allocated to each subcarrier even within the same frequency band. It is possible as described above.

Figure 6 is a diagram illustrating a specific application example of an interference minimization method performed by an interference minimization device according to an embodiment of the present invention. Figure 6 shows an embodiment of the present invention applied to six example situations in a case where three bands with the same number of subcarriers coexist in the frequency domain when the total size of the frequency domain is 900 kHz. Here, since each band includes the same number of subcarriers, the bandwidth is proportional to the interwave spacing, which is the spacing between subcarriers. In other words, a band with a small interwave spacing has a relatively small bandwidth. In FIG. 6, the horizontal direction represents the frequency axis direction, and the height of the figure at a specific horizontal position represents the amount of power allocated to the subcarrier of the frequency corresponding to the horizontal position.

According to Case 1, since the interwave spacing is the same in all three bands, power can be allocated uniformly in all bands. In contrast, in Case 2, first, two bands with the same inter-wave spacing are arranged adjacent to each other as the second and third bands, and where the first and second bands are adjacent, subcarriers belonging to the first band with a small inter-wave spacing are placed adjacent to each other as the second and third bands. It is possible to ensure that higher power is allocated compared to subcarriers belonging to the second band. In Case 3, two bands with the same inter-wave spacing are arranged adjacent to each other as the second and third bands, but since the first band has a larger inter-wave spacing than the second band, in Case 3, contrary to Case 2, the subcarrier belonging to the first band can be allocated lower power than the subcarrier belonging to the second band. Case 4 and Case 5 are basically the same as Case 3, but the larger the difference in interwave spacing between two adjacent bands (the first band and the second band), the more the two bands become adjacent to each other. It shows that the difference between the power allocated to the subcarriers belonging to the first band and the power allocated to the subcarriers belonging to the second band increases.

In Case 6, when the three bands have different inter-wave spacing, the band with the smallest inter-wave spacing can be placed in the center as the second band, and the remaining bands can be placed on both sides as the first band and third band, respectively. In the case of the second band, higher power is allocated to edge subcarriers than to the center subcarriers, and in the first and third bands, inter-band interference is minimized by allocating lower power to subcarriers closer to the first band than to subcarriers farther from the first band. can do.

According to an embodiment of the present invention as described so far, inter-band interference that may occur when a plurality of bands with different subcarrier spacing coexist in the frequency domain is minimized by optimizing the placement and power allocation of each band. By doing so, the reliability and efficiency of data transmission can be greatly improved.

Combinations of each block of the block diagram and each step of the flow diagram attached to the present invention may be performed by computer program instructions. Since these computer program instructions can be mounted on the encoding processor of a general-purpose computer, special-purpose computer, or other programmable data processing equipment, the instructions performed through the encoding processor of the computer or other programmable data processing equipment are included in each block or block of the block diagram. Each step of the flowchart creates a means to perform the functions described. These computer program instructions may also be stored in computer-usable or computer-readable memory that can be directed to a computer or other programmable data processing equipment to implement a function in a particular way, so that the computer-usable or computer-readable memory The instructions stored in can also produce manufactured items containing instruction means that perform the functions described in each block of the block diagram or each step of the flow diagram. Computer program instructions can also be mounted on a computer or other programmable data processing equipment, so that a series of operational steps are performed on the computer or other programmable data processing equipment to create a process that is executed by the computer, thereby generating a process that is executed by the computer or other programmable data processing equipment. Instructions that perform processing equipment may also provide steps for executing functions described in each block of the block diagram and each step of the flow diagram.

Additionally, each block or each step may represent a module, segment, or portion of code that includes one or more executable instructions for executing specified logical function(s). Additionally, it should be noted that in some alternative embodiments it is possible for the functions mentioned in the blocks or steps to occur out of order. For example, two blocks or steps shown in succession may in fact be performed substantially simultaneously, or the blocks or steps may sometimes be performed in reverse order depending on the corresponding function.

The above description is merely an illustrative explanation of the technical idea of the present invention, and those skilled in the art will be able to make various modifications and variations without departing from the essential quality of the present invention. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but are for illustrative purposes, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention shall be interpreted in accordance with the claims below, and all technical ideas within the scope equivalent thereto shall be construed as being included in the scope of rights of the present invention.

According to an embodiment of the present invention, by minimizing inter-band interference that may occur when a plurality of bands with different subcarrier spacings coexist within a certain frequency region in a mobile communication system supporting frequency division multiplexing, the mobile communication system In data transmission through , the reliability and efficiency of transmission can be greatly improved.

100: Interference minimization device
110: Interface unit
120: Subcarrier placement unit
130: Power allocation unit
140: storage unit

Claims (14)

In a mobile communication system supporting frequency division multiplexing (FDM), for a signal transmission terminal for transmitting a wireless signal using a plurality of subcarriers belonging to a frequency range defined on the frequency axis, the subcarriers As a device to minimize interference between
The frequency domain is divided into a plurality of frequency bands, each of the subcarriers is placed at a different position on the frequency axis within the frequency band, and each frequency band includes at least two of the subcarriers, and the frequency band is divided into a plurality of frequency bands. a subcarrier arrangement unit that ensures that the frequency spacing between adjacent subcarriers within each is equal to the interwave spacing determined for each frequency band; and
Power is allocated to each of the subcarriers, and when two subcarriers adjacent to each other on the frequency axis among the subcarriers belong to different frequency bands among the frequency bands, the subcarriers belonging to a frequency band with a smaller interwave spacing among the two adjacent subcarriers are assigned power. Comprising a power allocation unit that allocates higher power
Interference minimization device. According to claim 1,
The interwave spacing in each of the frequency bands is determined to be an integer multiple of the interwave spacing with the smallest value among the interwave spacings.
Interference minimization device. According to claim 1,
The subcarrier arrangement unit is configured to ensure that the frequency band with the smallest interwave spacing among the frequency bands includes the smallest number of subcarriers.
Interference minimization device. According to claim 1,
When there are two or more frequency bands with a larger inter-wave spacing than the frequency band with the smallest inter-wave spacing among the frequency bands, the subcarrier arrangement unit is located on both sides of the frequency band with the smallest inter-wave spacing among the frequency bands on the frequency axis, At least one of the frequency bands is located in each
Interference minimization device. According to claim 1,
The subcarrier arrangement unit arranges frequency bands with the same interwave spacing among the frequency bands adjacent to each other on the frequency axis.
Interference minimization device. According to claim 1,
The subcarrier arrangement unit is configured to alternately arrange an unused frequency band that does not include a subcarrier and a frequency band that includes a subcarrier among the frequency bands on the frequency axis.
Interference minimization device. According to claim 1,
The power allocation unit, for subcarriers included in a frequency band with a smaller interwave spacing than the two adjacent frequency bands on both sides of the frequency axis, provides higher power to the edge subcarrier than to the center subcarrier based on the frequency axis. and assign
Among the frequency bands, the inter-wave spacing is larger than that of a frequency band adjacent to one side of the frequency axis, and the inter-wave spacing is smaller than that of a frequency band adjacent to the other side, or for a subcarrier included in a frequency band in which no frequency band adjacent to the other side exists, the frequency band Allocating lower power to the subcarrier at the edge of the one side relative to the axis than to the subcarrier at the edge of the other side.
Interference minimization device. In a mobile communication system supporting frequency division multiplexing, a signal transmission terminal for transmitting a wireless signal using a plurality of subcarriers belonging to a frequency domain defined on the frequency axis, as a method for minimizing interference between the subcarriers,
The frequency domain is divided into a plurality of frequency bands, each of the subcarriers is placed at a different position on the frequency axis within the frequency band, and each frequency band includes at least two of the subcarriers, and the frequency band is divided into a plurality of frequency bands. A first step of ensuring that the frequency spacing between adjacent subcarriers within each is equal to the interwave spacing determined for each frequency band; and
Power is allocated to each of the subcarriers, and when two subcarriers adjacent to each other on the frequency axis among the subcarriers belong to different frequency bands among the frequency bands, the subcarriers belonging to a frequency band with a smaller interwave spacing among the two adjacent subcarriers are assigned power. comprising a second stage allocating higher power
How to minimize interference. According to claim 8,
The interwave spacing in each of the frequency bands is determined to be an integer multiple of the interwave spacing with the smallest value among the interwave spacings.
How to minimize interference. According to claim 8,
The first step includes ensuring that the frequency band with the smallest interwave spacing among the frequency bands includes the smallest number of subcarriers.
How to minimize interference. According to claim 8,
In the first step, when there are two or more frequency bands with a larger inter-wave spacing than the frequency band with the smallest inter-wave spacing among the frequency bands, on both sides of the frequency band with the smallest inter-wave spacing among the frequency bands on the frequency axis, , comprising the step of ensuring that at least one of the frequency bands is located respectively.
How to minimize interference. According to claim 8,
The first step includes arranging frequency bands with the same interwave spacing among the frequency bands adjacent to each other on the frequency axis.
How to minimize interference. According to claim 8,
The first step includes arranging an unused frequency band that does not include a subcarrier among the frequency bands and a frequency band that includes a subcarrier alternately on the frequency axis.
How to minimize interference. According to claim 8,
In the second step, for the subcarriers included in the frequency band with a smaller interwave spacing than the two adjacent frequency bands on both sides of the frequency axis, the edge subcarrier is higher than the central subcarrier based on the frequency axis. allocating power; and
Among the frequency bands, the inter-wave spacing is larger than that of a frequency band adjacent to one side of the frequency axis, and the inter-wave spacing is smaller than that of a frequency band adjacent to the other side, or for a subcarrier included in a frequency band in which no frequency band adjacent to the other side exists, the frequency band Comprising the step of allocating lower power to the subcarrier at the edge of the one side than to the subcarrier at the edge of the other side based on the axis.
How to minimize interference.

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