KR20230128928A - Communicaiton method for avoiding interference and communication device thereof - Google Patents

Abstract

According to one embodiment, a communication method calculates a receiving power change amount between OFDM symbols corresponding to a receiving signal within a slot, determines whether there is an interference symbol in the receiving signal based on the receiving power change amount between the OFDM symbols, detects a section including the interference symbol in the slot according to determination about there is the interference symbol, determines whether an RS symbol is included in the section including the interference symbol, and determines an MMSE covariance matrix corresponding to the interference symbol according to the determination about the RS symbol is included in the section including the interference symbol.

Description

Communication method and communication device for avoiding interference

The disclosure below relates to a communication method and communication device for interference avoidance.

When interference is caused by a mini-slot of another adjacent cell, reception performance of a physical uplink shared channel (PUSCH) of a user equipment (UE) of a target cell may deteriorate. At this time, the interference and noise ratio (INR) of the minislot is often higher than the SNR of the target user equipment (target UE), and the received signal to noise ratio (SNR) required for detection of the target user equipment is as much as the INR of the interference signal. As required, it may be important to determine whether there is an interfering signal such as a mini-slot in a symbol of the target user device.

In addition, various patterns of interference such as mini-slots may cause different interference in each of a data symbol corresponding to a data signal and an RS symbol corresponding to a reference signal (RS). Accordingly, when nulling is performed as a result of noise and interference (NI) estimation of an RS symbol despite the difference in interference generated in each of the data signal and the reference signal, performance degradation may occur in the data symbol.

When receiving a minimum mean squared error (MMSE) channel estimation result of a physical uplink shared channel (PUSCH) in an interference environment, a covariance matrix so that noise and interference (NI) are well nulled ), it is necessary to carefully determine whether there is interference in the current received symbol. In addition, information about whether such interference affects only data symbols corresponding to data signals or whether there is interference in reference signal (RS) symbols corresponding to reference signals may also be important.

However, if a change point is found according to the number of OFDM symbols affected by the interference signal within a slot and/or the INR of the interference signal, a covariance matrix reflecting the optimal noise and interference (NI) according to each interference pattern cannot be set. .

Various embodiments may determine an interfering symbol even when there is no interference in all OFDM symbols in a slot or there is interference in all OFDM symbols, or even if an interference-to-noise ratio (INR) is as small as 0 dB. .

Various embodiments may determine a covariance matrix such that noise and interference (NI) are well nulled.

Various embodiments may perform a series of PUSCH reception processes for determining the amount of interference, determining the presence or absence of an interference signal, and setting a covariance matrix so that optimal noise and interference (NI) are reflected in each interference pattern.

According to an embodiment, a communication method includes an operation of calculating an amount of change in received power between OFDM symbols corresponding to a received signal within a slot, and determining whether an interference symbol is present in the received signal based on the amount of change in received power between the OFDM symbols. determining whether the interference symbol is present, detecting a section including the interference symbol within the slot, determining whether a reference signal (RS) symbol is included in the section including the interference symbol, in the slot and determining whether a minimum mean squared error (MMSE) covariance matrix corresponding to the interfering symbol is determined according to the operation of performing the interfering symbol, and determining whether the RS symbol is included in the interval including the interfering symbol.

According to an embodiment, a communication apparatus calculates a communication interface for receiving a received signal in a slot, a received power change amount between OFDM symbols corresponding to the received signal, and based on the received power change amount between the OFDM symbols, It is determined whether there is an interference symbol in a received signal, and according to the determination that there is an interference symbol, a section including the interference symbol is detected in the slot, and a reference signal (RS) symbol is included in the section including the interference symbol. and a processor for determining whether the interfering symbol is included, and determining an MMSE covariance matrix corresponding to the interfering symbol according to whether the RS symbol is included in the interval including the interfering symbol.

According to an embodiment, performance deterioration due to interference may be reduced by reflecting interference and noise well in various interference pattern environments.

According to an embodiment, an environment in which there is no change in received power between OFDM symbols in a slot through appropriate noise and interference (NI) settings in various interference patterns (eg, no interference in all OFDM symbols in a slot or all OFDM symbols in a slot) BLER (block error rate) performance degradation due to misjudgment due to channel change can be improved even when symbols have interference)

In addition to this, various effects identified directly or indirectly through this document may be provided.

1 is a diagram for explaining a frame structure and basic terms for wireless communication according to an embodiment.
2 is a diagram for explaining interference caused by a mini-slot according to an embodiment.
3 is a block diagram of a communication device according to an embodiment.
4 is a diagram for explaining an operation of a power variation calculation unit according to an exemplary embodiment.
5 is a diagram for explaining an operation of an interference detection determination unit according to an exemplary embodiment.
6 is a diagram for explaining operations of an interference interval detection unit and an RS symbol check unit according to an embodiment.
7 is a diagram for explaining a method of detecting an interference section by an interference section detector according to an embodiment.
8 is a diagram for explaining an operation of a covariance matrix determiner according to an exemplary embodiment.
9 is a diagram for explaining the operation of a covariance matrix determiner according to another embodiment.
10 is a flowchart illustrating a communication method according to an exemplary embodiment.

Various embodiments of this document and terms used therein are not intended to limit the technical features described in this document to specific embodiments, but should be understood to include various modifications, equivalents, or substitutes of the embodiments. In connection with the description of the drawings, like reference numbers may be used for like or related elements. The singular form of a noun corresponding to an item may include one item or a plurality of items, unless the relevant context clearly dictates otherwise. In this document, "A or B", "at least one of A and B", "at least one of A or B", "A, B or C", "at least one of A, B and C", and "A Each of the phrases such as "at least one of , B, or C" may include any one of the items listed together in that phrase, or all possible combinations thereof. Terms such as "first", "second", or "first" or "secondary" may simply be used to distinguish that component from other corresponding components, and may refer to that component in other respects (eg, importance or order) is not limited. A (eg, first) component is said to be "coupled" or "connected" to another (eg, second) component, with or without the terms "functionally" or "communicatively." When mentioned, it means that the certain component may be connected to the other component directly (eg by wire), wirelessly, or through a third component.

The term "module" used in various embodiments of this document may include a unit implemented in hardware, software, or firmware, and is interchangeable with terms such as, for example, logic, logical blocks, parts, or circuits. can be used as A module may be an integrally constructed component or a minimal unit of components or a portion thereof that performs one or more functions. For example, according to one embodiment, the module may be implemented in the form of an application-specific integrated circuit (ASIC).

Various embodiments of this document may be implemented as software including one or more instructions stored in a storage medium readable by a machine. For example, the processor of the device may call at least one command among one or more commands stored from a storage medium and execute it. This enables the device to be operated to perform at least one function according to the at least one command invoked. The one or more instructions may include code generated by a compiler or code executable by an interpreter. The device-readable storage medium may be provided in the form of a non-transitory storage medium. Here, 'non-temporary' only means that the storage medium is a tangible device and does not contain a signal (e.g. electromagnetic wave), and this term refers to the case where data is stored semi-permanently in the storage medium. It does not discriminate when it is temporarily stored.

According to one embodiment, the method according to various embodiments disclosed in this document may be provided by being included in a computer program product. Computer program products may be traded between sellers and buyers as commodities. A computer program product is distributed in the form of a device-readable storage medium (e.g. compact disc read only memory (CD-ROM)), or through an application store (e.g. Play Store™) or on two user devices (e.g. It can be distributed (eg downloaded or uploaded) online, directly between smart phones. In the case of online distribution, at least part of the computer program product may be temporarily stored or temporarily created in a device-readable storage medium such as a manufacturer's server, an application store server, or a relay server's memory.

According to various embodiments, each component (eg, module or program) of the above-described components may include a single object or a plurality of entities, and some of the plurality of entities may be separately disposed in other components. there is. According to various embodiments, one or more components or operations among the aforementioned corresponding components may be omitted, or one or more other components or operations may be added. Alternatively or additionally, a plurality of components (eg modules or programs) may be integrated into a single component. In this case, the integrated component may perform one or more functions of each of the plurality of components identically or similarly to those performed by a corresponding component of the plurality of components prior to the integration. . According to various embodiments, the actions performed by a module, program, or other component are executed sequentially, in parallel, iteratively, or heuristically, or one or more of the actions are executed in a different order, or omitted. or one or more other actions may be added.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. In the description with reference to the accompanying drawings, the same reference numerals are given to the same components regardless of reference numerals, and overlapping descriptions thereof will be omitted.

FIG. 1 is a diagram for explaining a frame structure and basic terms used in a communication method according to an embodiment. Referring to FIG. 1, a diagram 100 illustrating a frame structure and basic terms of 5G new radio (NR) according to an embodiment is shown.

5NR is a new radio access technology (RAT) developed by 3GPP for 5G (fifth generation) mobile networks and can support operation in the spectrum, eg, sub-1 GHz to millimeter wave bands. Like long term evolution (LTE), NR may use an orthogonal frequency division multiplexing (OFDM) scheme. Orthogonal Frequency Division Multiplexing (OFDM) divides one piece of information into several carriers and multiplexes them into subcarriers with orthogonality added to minimize the distance between the divided carriers. method may apply. Here, a 'carrier' may refer to an electromagnetic wave (typically a sine wave) modulated with an input signal to transfer information in communication, and the carrier may generally have a much higher frequency than the input signal. A carrier may also be called a 'carrier'. The 'subcarrier' may correspond to a signal to which orthogonality is added and used within a base band to multiplex video, audio, and data, for example, before modulation of a carrier for transmission. The modulated carrier may be demodulated into a primary carrier and a subcarrier respectively at the receiving side. A subcarrier may be referred to as a 'subcarrier'.

NR adopts, for example, a flexible subcarrier spacing of 2μ·15kHz (μ = 0, 1, .., 4) scaled to the basic 15kHz subcarrier spacing (SCS) of long term evolution (LTE) It can be done, but is not necessarily limited thereto.

A 'frame' may have, for example, a duration of 10ms and consist of 10 subframes. Each of the subframes may include, for example, two slots including 14 orthogonal frequency-division multiplexing (OFDM) symbols. A 'slot' may correspond to a unit for transmission in which scheduling is operated.

NR allows a transmission to start on any OFDM symbol and continue for as few symbols (e.g. mini-slots) as needed for communication. As will be discussed in more detail below, mini-slot transmission facilitates very low latency for critical data by lean carrier design principles aimed at minimizing transmission and avoiding interference on other links. can be minimized.

A 'resource block (RB)' may be composed of, for example, 12 consecutive subcarriers in the frequency domain. A single NR carrier may be limited to a maximum of 3300 active subcarriers and a maximum bandwidth of 400 MHz. Hereinafter, 'RB' or 'rb' may correspond to a unit of subcarriers (or tones) in one slot composed of, for example, 14 OFDM symbols. 1RB may correspond to 12 subcarriers.

For example, a radio resource available for a carrier having a given subcarrier spacing (SCS) in a subframe of 1 ms period is a 'resource grid' composed of subcarriers in the frequency domain and OFDM symbols in the time domain. ' can be expressed as Each resource element (RE) of the resource grid may occupy one subcarrier in the frequency domain and one OFDM symbol in the time domain.

A bandwidth portion may correspond to a subset of contiguous resource blocks (RBs) in a carrier. Up to four bandwidth segments can be configured in a user equipment (or communication device) for each uplink (UL) and downlink (DL), but only one bandwidth segment can be active per transmission direction at any given time.

Referring to FIG. 2 , a diagram for explaining interference by a mini-slot according to an embodiment is shown. Referring to FIG. 2 , a diagram 200 for explaining a mini slot according to an embodiment is shown.

Here, a 'mini slot' may start at an arbitrary OFDM symbol position within the slot and end within the slot. A mini-slot has a smaller size than a general slot, and may correspond to a slot having a length of 2, 4, or 7 small OFDM symbols, for example.

For example, when a signal corresponding to a mini-slot of an adjacent cell is received as an uplink interference signal of a base station, various interference patterns may occur. In this case, since the location of an OFDM symbol having interference in a mini-slot may change every time, a new type of interference pattern may exist in each slot. At this time, if the variation of the received signal is small due to the mini-slot, it is determined that there is no interference in the OFDM symbol with interference, or change points cannot be found because all OFDM symbols in the slot have interference, or even if change points are found, only some symbols have interference. erroneously determines that there is a physical uplink shared channel (PUSCH) performance may be deteriorated.

3 is a block diagram of a communication device according to an embodiment. Referring to FIG. 3 , the processor of the communication device 300 according to an embodiment includes, for example, a power variation calculation module 310, an interference detection determination module 320, an interference section detection module 330, and an RS symbol. It may include a check module 340 , and a covariance matrix determination module 350 .

The communication device 300 may find the position of the resource block (rb) to which the interference resource belongs and the position (k) of the OFDM symbol to obtain optimal performance in various interference patterns.

The power variation calculation module 310 may calculate a received power variation between OFDM symbols corresponding to a received signal within a slot. The power variation calculation module 310 calculates, for example, the received signal of the k-th OFDM symbol in the received signal vector of N _rx x 1 (where N _rx means the number of receiving antennas). Based on , a metric S(k, rb) for finding a changing point can be calculated. Here, k represents the number of OFDM symbols, and s may represent, for example, resource blocks (RBs) including 12 subcarriers. The number of resource blocks may be, for example, 12, but is not necessarily limited thereto.

The metric S(k,rb) may correspond to a metric representing a received power variation between OFDM symbols. rb may indicate the number (location) of resource blocks. The metric S(k,rb) is, for example, reception between the second average reception powers of all OFDM symbols included in a slot compared to the first average reception powers of resource block (rb) units of OFDM symbols of each resource unit. The amount of change in power may be calculated and accumulated. For example, the greater the interference included in the received signal, the greater the received power variation may appear. A method of calculating the received power change amount by the power change calculation module 310 will be described in more detail with reference to FIG. 4 below.

The interference detection determination module 320 may determine whether or not there is an interference symbol in the received signal based on the received power variation S(k,rb) between symbols calculated by the power variation calculation module 310. The interference detection determination module 320 calculates, for example, a first difference between the maximum value of the received power variation S(k,rb) and the minimum value of the received power variation S(k,rb), and determines the first difference and Depending on the comparison result between the set thresholds, whether or not there is an interference symbol in the received signal may be determined.

For example, if it is determined that there is an interference symbol in the received signal, the interference detection determination module 320 may set search_on(rb) = 1 so that the interference section detection module 330 detects the interference section. In contrast, when it is determined that there is no interference symbol in the received signal, the interference detection determination module 320 may set search_on(rb) = 0. When search_on(rb) = 0, the interference section detection module 330 may end its operation.

A method for the interference detection determination module 320 to determine whether or not there is an interference symbol in the received signal will be described in more detail with reference to FIG. 5 below.

The interference section detection module 330 may detect a section including an interference symbol ('interference section') within a slot according to the determination of the interference detection decision module 320 that there is an interference symbol. The interference section detection module 330 detects, for example, two changing points in which the slope of the received power change amount changes within the slot, and then detects a section including the interference symbol using the codes of the changing points. can do. The interference section detection module 330 uses a first code corresponding to a first change point having a large absolute value among two change points and a second code corresponding to a second change point having a small absolute value among the two change points, and uses an interference symbol. This included section can be detected. The interference section detection module 330 may transmit an indicator (eg, indicator(k, rb)) including information indicating a section including an interference symbol to the RS symbol check module 340. In this case, the information indicating the interval including the interference symbol may include, for example, the location of the resource block (rb) and the OFDM symbol (k) corresponding to the interval including the interference symbol, but is not necessarily limited thereto. .

The RS symbol check module 340 determines whether a reference signal (RS) symbol is included in the interval including the interference symbol detected by the interference interval detection module 330, that is, interference included in the received signal corresponds to the data signal. It is possible to determine whether the RS symbol corresponding to the reference signal (reference signal) as well as the data symbol to be affected. For example, when it is determined that an RS symbol is included in a section including an interfering symbol, the RS symbol check module 340 transmits information (eg, indicator (k, rb)) of the section to the covariance matrix determination module 350. ) can be forwarded to

A method for the interference section detection module 330 to detect a section including an interference symbol in a slot and an RS symbol check module 340 to determine whether a reference signal (RS) symbol is included in a section including an interference symbol The method will be described in more detail with reference to FIGS. 6 to 7 below.

The covariance matrix determination module 350 may determine a minimum mean squared error (MMSE) covariance matrix corresponding to the interference symbol according to the determination of the RS symbol check module 340. For example, when an RS symbol is included in a period including an interfering symbol, the covariance matrix determination module 350 may set parameters of a covariance matrix according to MMSE channel estimation based on an indicator of the RS symbol. there is. Hereinafter, 'covariance matrix according to minimum mean squared error (MMSE) channel estimation' can be simplified and expressed as 'MMSE covariance matrix'. A method of determining the MMSE covariance matrix corresponding to the interference symbol by the covariance matrix determination module 350 will be described in more detail with reference to FIG. 8 below.

According to an embodiment, the covariance matrix determining module 350 may cancel interference with respect to a received signal based on determining whether an RS symbol is included in a period including an interfering symbol. The covariance matrix determination module 350 may cancel interference by, for example, a whitening method and/or an interference rejection combining (IRC) method, but is not necessarily limited to the above example. For example, a method of performing whitening by the covariance matrix determination module 350 will be described in more detail with reference to FIG. 9 below.

4 is a diagram for explaining an operation of a power variation calculation module according to an exemplary embodiment. Referring to FIG. 4 , the power change calculation module 310 according to an embodiment may calculate received power change between symbols through operations 410 to 430 .

In operation 410, the power change calculation module 310 calculates, for example, first average received powers in units of resource blocks (rb) of OFDM symbols in units of resources. can be calculated. Here, the 'resource block (rb) unit' may also be referred to as a 'subcarrier unit'.

In operation 420, the power variation calculation module 310 performs a second average received power of all OFDM symbols included in the slot. For example, it can be calculated as in Equation 1 below.

where the received signal power Is the received signal of the k th OFDM symbol may be about corresponds to the time order (position) of the OFDM symbol, may correspond to a frequency index corresponding to the location of resource blocks. At this time, represents the number of tones to average the power of the received signal, and may be a value considering a multiple of the frequency rb. A tone may correspond to subcarriers. as an example , it is 1RB in the NR/LTE standard. As the value of is larger, it has a stochastic characteristic, so an appropriate value can be selected in consideration of the frequency selectivity of the channel.

When the power variation calculation module 310 calculates the average power of the received signal, the noise is averaged out, and the characteristics of the channel and/or interference are appropriately determined so as to remain. can be set. The power variation calculation module 310 averages the frequency axis even when calculating the covariance, the same as the number of frequency resources to be averaged when calculating the covariance. can be set. In operation 430, the power variation calculation module 310 determines the received power variation between symbols, that is, the first average received powers. and the second average received power Amount of change in received power between livers can be calculated. The power change amount calculation module 310 is a received power change between second average received powers of all OFDM symbols included in a slot compared to first average received powers in subcarrier units of OFDM symbols. Is accumulated from the first symbol, for example, as shown in Equation 2 below, and the received signal power z (k) of the k th OFDM symbol of the received signal y by accumulating the received power change amount s (k-1) of the previous symbol can be saved

5 is a diagram for explaining an operation of a detection/non-determination module according to an exemplary embodiment. Referring to FIG. 5 , the interference detection determination module 320 according to an embodiment may determine whether an interference symbol is present in a received signal through operations 510 to 530 .

In operation 510, the interference detection determination module 320 determines the received power variation within the slot. can be calculated. The interference detection determination module 320 may calculate a first difference between the maximum value of the received power variation and the minimum value of the received power variation as shown in Equation 3 below, for example.

In operation 520, the interference detection determination module 320 sets a preset threshold value. can be called. At this time, the threshold For example, may be determined based on at least one of a reception power distribution of a received signal, a signal to noise ratio (SNR) for a reference signal (RS) symbol included in the received signal, and noise and interference (NI) of the RS symbol. there is.

In operation 530, the interference detection determination module 320 may determine whether or not there is an interference symbol in the received signal according to a comparison result between the first difference calculated in operation 510 and the threshold called in operation 520.

For example, when the first difference is greater than the set threshold TH ( ), the communication device may determine that there is an interference symbol in the received signal. If it is determined that there is an interference symbol in the received signal, the interference detection determination module 320 may set search_on(rb) = 1 so that the interference section detection module 330 detects the interference section.

On the other hand, when the first difference is less than or equal to the set threshold ( ), the communication device may determine that there is no interfering symbol in the received signal. When it is determined that there is no interference symbol in the received signal, the interference detection determination module 320 may set search_on(rb) = 0. When search_on(rb) = 0, the interference section detection module 330 may end its operation.

Operation 530 is an operation of determining the amount of interference, and may correspond to a process for setting an appropriate MMSE covariant matrix according to the amount of interference.

Depending on the embodiment, the interference detection determination module 320 determines, for example, the maximum value of the received power change amount as shown in Equation 4 below ( ) and the average received power of the demodulation reference signal (DMRS) symbols included in the received signal ( ) and the second difference between ( ) can be calculated.

At this time, since the noise and interference (NI) and the received signal corresponding to the DMRS symbol are known in advance, the average received power of the DMRS symbol ( can be calculated.

The interference detection determination module 320 may determine whether or not there is an interference symbol in the received signal according to a comparison result between the second difference and the set threshold. At this time, similar to the first difference, when the second difference is greater than a set threshold, the interference detection determination module 320 may determine that there is an interference symbol in the received signal. In contrast, when the second difference is less than or equal to the set threshold, the interference detection determination module 320 may determine that there is no interference symbol in the received signal.

According to embodiments, the threshold may be determined regardless of an operating SNR of a communication device (eg, a user equipment (UE)). For example, when a base station receives signals from several user equipments, SNRs estimated from RS symbols may be different for each user equipment. In this case, a fixed value obtained from the received signal power distribution may be used as a threshold so that the INR operates only at xdB or higher regardless of the SNR, as shown in Equation 5 below.

Here, config_TH may correspond to a fixed value obtained from the received signal power distribution.

When a fixed value (config_TH) is used as a threshold value as shown in Equation 5, as the SNR increases, the probability of determining whether or not there is an interference symbol in the received signal may decrease. According to Equation 5, it is possible to improve the selection probability of an interference symbol at a high SNR.

Alternatively, the threshold may be determined using a channel estimation value. For example, the threshold may be set using the SNR for the RS symbol as shown in Equation 6 below.

Here, CE_SNR may correspond to the SNR for the RS symbol.

For example, assuming that an RS symbol contains an interference signal, noise and SNR including interference can be obtained from a channel value experienced by the user equipment and an estimate of the noise of the user equipment from the RS symbol. On the other hand, if there is no interference signal in the RS symbol, even if it is assumed that the channel value experienced by the user device is the same, the interference signal is not included and the noise estimation value will be small, so the SNR can be estimated higher than in the case of interference. In this way, the SNR obtained from the channel value experienced by the user equipment and the noise estimation value of the user equipment in the RS symbol can be expressed as 'CE_SNR'. When based on operating SNRs different for each user device, actual interference caused by CE_SNR will affect noise, so if it is assumed that there is more noise, the threshold can be obtained as in Equation 6 above.

In addition, the threshold may be set using noise and interference (NI) of the RS symbol instead of CE_SNR, for example, as shown in Equation 7 below.

For example, since RSs between adjacent cells are orthogonal, interference reflection for SNR determined by channel estimation may be inaccurate. In this case, a threshold may be set as shown in Equation 7 using NI for measuring interference from a received signal.

For example, if the INR is 20 dB and the SNR is 30 dB, so the SIR is large, it indicates a large value in the interference signal standard, but the operating SNR of the communication device is high, so the amount of interference may not be detected compared to the SNR of the communication device. Therefore, it may be important to appropriately set a threshold to compare with the first difference (or second difference) (s_diff).

6 is a diagram for explaining operations of an interference section detection module and an RS symbol check module according to an embodiment. Referring to FIG. 6, the interference section detection module 330 according to an embodiment detects an interference section through operations 610 to 670, and the RS symbol check module 340 performs a section including an interference symbol through operation 680. It may be determined whether a reference signal (RS) symbol is included in .

According to the determination of the interference detection or non-interference determination module 320 that there is an interference symbol, the interference section detection module 330 may detect a section including the interference symbol within the slot.

In operation 610, the interference section detection module 330 may determine whether search_on(rb) == 1. For example, if search_on(rb) == not 1 (no) corresponds to a case in which there is no interference symbol in the received signal, the interference section detection module 330 includes information indicating a section including an interference symbol. The indicator (k) may be set to 0 and the operation may be terminated.

On the other hand, if search_on(rb) == 1 (yes) corresponds to the case where there is an interference symbol in the received signal, the interference section detection module 330 performs the following operations 630 to 670 for a section including the interference symbol. can be detected.

In operation 630, the interference section detection module 330 determines two changing points (k ₁ ,k ₂ ) can be detected.

For example, as shown in Equation 8 below, the interference section detection module 330 detects a change point having a large absolute value among the two change points (k ₁ , k ₂ ) as k ₁ , and a change point having a small absolute value as k . ₂ can be detected. Equations 8 and 9 below assume an rb unit operation, and in Equations 8 and 9, the rb index is omitted.

In operation 640, the interference section detection module 330 may determine whether signs sign_k ₁ and sing_k ₂ of the change points k ₁ and k ₂ are positive numbers or negative numbers. The interference section detection module 330 determines the first sign (sign_k 1 ) of the first change point (k 1 ) having the largest absolute value among the two change points (k ₁ , _{k 2} ) and the second change point having the smallest absolute value among the two change points (k 1 , _{k 2} ). 2 The second sign (sing_k ₂ ) of the change point (k ₂ ) can be determined. The interference section detection module 330 determines, for example, the first sign (sign_k ₁ ) of the first change point (k ₁ ) and the second sign (sing_k ₂ ) of the second change point (k ₂ ) as shown in Equation 9 below. can be identified.

Here, the sign function can represent 1 if the sign of the change point is a positive number and 0 if the sign of the change point is a negative number.

In operation 650, the interference interval detection module 330 may determine whether the first sign (sign_k ₁ ) and the second sign (sing_k ₂ ) are different. When it is determined in operation 650 that the first sign (sign_k ₁ ) and the second sign (sing_k ₂ ) are the same, in operation 660, the interference section detection module 330 determines whether the first sign is a positive number ('+') or a negative number ('-'). '), different intervals may be determined as intervals including interference symbols ('interference intervals'). In operation 660, for example, if the first code is a positive number ('+'), the interference section detection module 330 may determine a second section to the left of the first change point (k ₁ ) as an interference section. Also, if the first code is a negative number ('-'), the interference section detection module 330 may determine a third section to the right of the first change point (k ₁ ) as an interference section. In contrast, when it is determined in operation 650 that the first sign (sign_k ₁ ) and the second sign (sing_k ₂ ) are different, in operation 670, the interference section detection module 330 determines the first change point (k ₁ ) and the second change point ( k ₂ ) may be determined as an interference interval.

The interference section detection module 330 may transmit an indicator (eg, indicator(k, rb)) including information indicating an interference section, determined through operation 660 or operation 670, to the RS symbol check module 340. In this case, the information indicating the interference interval may include, for example, the location of the resource block (rb) and the OFDM symbol (k) corresponding to the interval including the interference symbol, but is not necessarily limited thereto.

In operation 680, the RS symbol check module 340 determines whether a reference signal (RS) symbol is included in the interval including the interference symbol detected in operation 660 or operation 670 (eg, the interval in which indicator(k)=1). can decide

For example, if the index of the DMRS symbol is included in the interval including the interference symbol, the RS symbol check module 340 sets indicator(k) = 0 to determine the interval including the interference symbol as an interference signal. may not be For example, when an interference signal exists in a downlink and uplink demodulation reference signal (DMRS) (hereinafter referred to as 'DMRS') symbol, the interference signal may be reflected in the NI estimation process. In this case, the RS symbol check module 340 assumes that DMRS-like interference exists in data symbols adjacent to the DMRS, and may not determine a section including the interference symbol as an interference signal. Here, 'DMRS' corresponds to a reference signal for downlink and uplink demodulation, and may be used by a receiving device to generate a channel estimate for demodulation of an associated physical channel. For example, the first DMRS instance is transmitted at the beginning of PDSCH/PUSCH transmission, so that channel estimation can be started early in the receiving device, thereby reducing processing latency.

In contrast, when the index of the DMRS symbol is not included in the interval including the interference symbol, the RS symbol check module 340 indicates an indicator including information indicating the interval including the interference symbol (e.g., indicator(k, rb). )) to the covariance matrix determination module 350. Here, the indicator (eg, indicator(k, rb)) is an input parameter used by the covariance matrix determination module 350 to set the MMSE covariance matrix for achieving optimal PUSCH block error rate (BLER) performance. It can be. Here, 'block error rate (BLER)' may correspond to a ratio of the number of erroneous blocks to the total number of blocks transmitted in the digital circuit.

7 is a diagram for explaining a method of detecting an interference section by an interference section detection module according to an embodiment. Referring to FIG. 7 , a graph 700 illustrating change points k _{1 and} k ₂ at which a slope of a received power change amount according to an exemplary embodiment is changed is shown.

The graph 700 shows, for example, the amount of change in received power between symbols calculated through the process described above with reference to FIG. 4 . may indicate Change amount of received power in the graph 700 Symbol index 4 and symbol index 8 in which the slope of x changes may correspond to change points. The interference section detection module 330 may detect an interference section based on symbols having different received signal powers, such as symbol index 4 and symbol index 8.

The interference section detection module 330 may, for example, a change point having a large absolute value (eg, |-130|) among two change points corresponding to symbol index 4 and symbol index 8 (eg, change point corresponding to symbol index 4). ) may be detected as k ₁ , and a change point having a small absolute value (eg, |+120|) (eg, a change point corresponding to symbol index 8) may be detected as k ₂ .

The interference section detection module 330 may determine whether the signs of the change points k ₁ and k ₂ are positive or negative. The interference section detection module 330 determines the first sign (sign_k ₁ ) ('-') of the first change point (k ₁ ) having a large absolute value and the second sign (sing_k) of the second change point (k ₂ ) having a small absolute value. ₂ )('+') can be identified.

Since the first sign ('-') and the second sign ('+') are different from each other in the interference section detection module 330, the first change point (k 1 ) corresponding to symbol index 4 and the change point (k ₁ ) corresponding to symbol index 8 ( k ₂ ) may be determined as the interval including the interference symbol.

The interference section detection module 330 generates an indicator (eg, indicator(k, rb)) including information indicating the location of a resource block (rb) and an OFDM symbol (k) corresponding to the first section including the interference symbol. It can be transmitted to the RS symbol check module 340.

8 is a diagram for explaining an operation of a covariance matrix determination module according to an exemplary embodiment. Referring to FIG. 8 , the covariance matrix determination module 350 according to an embodiment may set an MMSE covariance matrix corresponding to an interference symbol in an interference rejection combining (MMSE-IRC) structure through operations 810 to 830. Here, 'IRC' may correspond to an interference rejection combining method for mitigating interference in a frequency domain with respect to a signal received in a communication system.

In operation 810, the covariance matrix determination module 350 determines, for example, whether a data symbol is included in an interval including an interference symbol having an estimated noise and interference (NI) corresponding to a subcarrier (k) or an RS symbol. You can decide whether this is included. In operation 810, if data symbols are included in the interval including interference symbols, 'indicator(k) == 1' becomes 'yes', and if data symbols are not included in the interval including interference symbols, 'indicator(k) == 1' becomes 'yes'. (k) == 1' can be 'no'.

For example, if it is determined in operation 810 that data symbols are not included in the interval including the interference symbol ('no'), in operation 820, the covariance matrix determining module 350 performs the estimated noise corresponding to the subcarrier k. A covariance matrix according to minimum mean squared error (MMSE) channel estimation corresponding to an interference symbol having (Rnn) and interference (Rhh) may be determined. A covariance matrix according to minimum mean squared error (MMSE) channel estimation can be simplified and expressed as 'MMSE covariance matrix'.

The covariance matrix determination module 350 may set parameters of the covariance matrix according to the MMSE channel estimation based on the indicator of the RS symbol.

In contrast, when it is determined in operation 810 that data symbols are included in the interval including the interference symbol ('yes'), in operation 830, the covariance matrix determination module 350 may determine a covariance matrix Ryy based on the received signal. there is. In operation 830, the covariance matrix determination module 350 determines, for example, a combined representation of a covariance matrix for interference plus noise in the frequency domain for at least one time slot of the received signal, pilot symbols of the at least one time slot. Determine the channel estimate for , and determine the covariance matrix by determining the IRC coefficient in the frequency domain for each symbol of the time slot based on the determined joint expression of the covariance matrix and the determined channel estimate.

9 is a diagram for explaining an operation of a covariance matrix determination module according to another embodiment. Referring to FIG. 9 , the covariance matrix determination module 350 according to an embodiment may perform whitening to cancel interference Rhh of the received signal Ryy through operations 910 to 930.

In operation 910, the covariance matrix determination module 350 includes, for example, a data symbol corresponding to a data signal in an interval including an interference symbol having an estimated noise and interference (NI) corresponding to the subcarrier k. It is possible to determine whether or not an RS symbol corresponding to a reference signal is included. In operation 910, if the data symbol is included in the interval including the interference symbol, 'indicator (k) == 1' becomes 'yes', and if the interval including the interference symbol does not include the data symbol, 'indicator (k) == 1' becomes 'yes'. (k) == 1' can be 'no'.

If it is determined in operation 910 that no data symbol is included in the interval including the interference symbol ('no'), in operation 920, the covariance matrix determining module 350 determines the estimated noise Rnn corresponding to the subcarrier k. Whitening may be performed or may not be performed.

For example, if not all data symbols are included in a section that includes interference symbols, performance degradation may occur if whitening is performed from data symbols to RS symbol noise (Rnn) because the NIs of data symbols and RS symbols are different. can Alternatively, when no data symbols are included in the interval including the interfering symbols, whitening may be performed by considering the NI of the data symbols as the NI of the covariance (Ryy) of the received signal. In this case, since nulling is performed based on the SNR of the communication device (eg, user equipment (UE)), greater performance degradation may occur than in the case of whitening the noise Rnn. When performance deterioration occurs in this way, it may be advantageous to not perform nulling, ie, whitening.

For example, if there is at least one data symbol along with an RS symbol in a section including an interference symbol, whitening to cancel interference for noise (Rnn) can be performed assuming that NIs of the RS symbol and the data symbol are similar. there is.

In contrast, when it is determined in operation 910 that data symbols are included in the interval including the interference symbol ('yes'), in operation 930, the covariance matrix determination module 350 determines a covariance matrix based on the received signal Ryy. , whitening may be performed to cancel interference with the received signal Ryy.

10 is a flowchart illustrating a communication method according to an exemplary embodiment. In the following embodiments, each operation may be performed sequentially, but not necessarily sequentially. For example, the order of each operation may be changed, or at least two operations may be performed in parallel.

Referring to FIG. 10 , the communication device according to an embodiment may determine a minimum mean squared error (MMSE) covariance matrix for noise and interference corresponding to an interference symbol through operations 1010 to 1050.

In operation 1010, the communication device may calculate a received power variation between OFDM symbols corresponding to a received signal within a slot. The communication device may calculate first average received powers in units of subcarriers of OFDM symbols, for example. The communication device may calculate the second average received power of all OFDM symbols included in one slot. The communication device may calculate a received power variation between the first average received powers and the second average received power.

In operation 1020, the communication device may determine whether an interference symbol is present in the received signal based on the amount of change in received power between OFDM symbols calculated in operation 1010. After calculating the first difference between the maximum value of the received power change amount and the minimum value of the received power change amount, the communication device may determine whether there is an interference symbol in the received signal according to a comparison result between the first difference and the set threshold value. For example, when the first difference is greater than a set threshold, the communication device may determine that there is an interference symbol in the received signal. Alternatively, when the first difference is less than or equal to the set threshold, the communication device may determine that there is no interfering symbol in the received signal.

At this time, the threshold is based on at least one of, for example, a received power distribution of the received signal, a signal to noise ratio (SNR) for a reference signal (RS) symbol included in the received signal, and noise and interference (NI) of the RS symbol. can be determined by

According to the embodiment, the communication device determines the maximum value of the received power variation (max s (k)) and the average received power (avg s (k), k = DMRS) of the DMRS (demodulation reference signal) symbols included in the received signal. A second difference (s _diff ) may be calculated, and based on a comparison result between the second difference and the set threshold, whether or not an interference symbol is present in the received signal may be determined. Similar to the first difference, when the second difference is greater than the set threshold, the communication device may determine that there is an interference symbol in the received signal. Alternatively, when the second difference is less than or equal to the set threshold, the communication device may determine that there is no interfering symbol in the received signal.

In operation 1030, the communication device may detect a section including the interference symbol in the slot according to the determination in operation 1020 that there is an interference symbol. The communication device may detect two changing points at which the slope of the received power change amount changes within the slot. The communication device uses a first code corresponding to a first change point having a large absolute value among two change points and a second code corresponding to a second change point having a small absolute value among the two change points to determine a section including an interference symbol. can be detected.

For example, when the first code and the second code are different, the communication device may determine a first section between the first change point and the second change point as a section including the interference symbol. Alternatively, when the first code and the second code are the same and the first code is a positive number, the communication device may determine a second section to the left of the first change point as a section including the interference symbol. Alternatively, when the first code and the second code are the same and the first code is a negative number, the communication device may determine a third section to the right of the first change point as a section including the interference symbol.

In operation 1040, the communication device may determine whether a reference signal (RS) symbol is included in the interval including the interference symbol detected in operation 1030.

In operation 1050, the communication device may determine a minimum mean squared error (MMSE) covariance matrix corresponding to the interference symbol according to the determination of whether the RS symbol is included in the interval including the interference symbol in operation 1040. For example, when an RS symbol is included in a period including an interference symbol, the communication device may set parameters of the MMSE covariance matrix based on an indicator of the RS symbol.

Depending on the embodiment, the communication device may perform whitening to cancel interference on the received signal based on determining whether the RS symbol is included in the interval including the interference symbol.

According to an embodiment, the communication method includes operation 1010 of calculating an amount of change in received power between OFDM symbols corresponding to a received signal within a slot, based on the amount of change in received power between OFDM symbols, whether there is an interference symbol in the received signal. Operation 1020 of determining whether or not there is an interference symbol, operation 1030 of detecting a section including the interference symbol in the slot according to the determination, whether a reference signal (RS) symbol is included in the section including the interference symbol Operation 1040 for determining whether or not, and operation 1050 for determining a minimum mean squared error (MMSE) covariance matrix corresponding to the interference symbol according to the determination whether the RS symbol is included in the interval including the interference symbol. can do.

According to an embodiment, the operation 1010 of calculating the amount of change in received power includes an operation of calculating first average reception powers in subcarrier units of the OFDM symbols, and a second average reception of all OFDM symbols included in the slot. An operation of calculating power, and an operation of calculating an operation of changing the received power between the first average received powers and the second average received power.

According to an embodiment, operation 1020 of determining whether there is an interference symbol includes an operation of calculating a first difference between the maximum value of the received power variation and the minimum value of the received power variation, and between the first difference and a set threshold. An operation of determining whether the interference symbol is present in the received signal according to a comparison result may be included.

According to an embodiment, operation 1020 of determining whether or not there is the interference symbol includes determining that the interference symbol exists in the received signal when the first difference is greater than the set threshold, and determining whether the first difference is the When it is less than or equal to the set threshold, determining that the interference symbol is not present in the received signal may be included.

According to an embodiment, the threshold is selected from among a received power distribution of the received signal, a signal to noise ratio (SNR) for a reference signal (RS) symbol included in the received signal, and noise and interference (NI) of the RS symbol. It can be determined based on at least one.

According to an embodiment, operation 1020 of determining whether there is the interference symbol calculates a second difference between the maximum value of the received power variation and the average received power of demodulation reference signal (DMRS) symbols included in the received signal. and an operation of determining whether the interference symbol is present in the received signal according to a comparison result between the second difference and a set threshold.

According to an embodiment, operation 1030 of detecting a section including the interference symbol includes an operation of detecting two changing points at which a slope of the amount of change in received power changes within the slot, and the two changing points. Detecting a section including the interference symbol using a first code corresponding to a first change point having a large absolute value among the two change points and a second code corresponding to a second change point having a small absolute value among the two change points. can include

According to an embodiment, in operation 1030 of detecting a section including the interference symbol, when the first code and the second code are different, a first section between the first change point and the second change point is the interference symbol. Determining a second interval to the left of the first change point as an interval including the interference symbol when the first code and the second code are the same and the first code is a positive number and, when the first code and the second code are the same and the first code is a negative number, determining a third section to the right of the first change point as a section including the interference symbol. can include

According to an embodiment, the operation 1050 of determining the MMSE covariance matrix sets parameters of the MMSE covariance matrix based on an indicator of the RS symbol when the RS symbol is included in a period including the interference symbol can include

According to an embodiment, the communication method may further include canceling interference with the received signal based on determining whether the RS symbol is included in a period including the interference symbol.

According to an embodiment, the communication device 300 calculates an amount of change in received power between OFDM symbols corresponding to a received signal within a slot, and based on the amount of change in received power between OFDM symbols, an interference symbol is generated in the received signal. determining whether there is an interference symbol, detecting a section including the interference symbol within the slot, and determining whether a reference signal (RS) symbol is included in the section including the interference symbol, in the slot, according to the determination that the interference symbol exists. and a processor for determining an MMSE covariance matrix corresponding to the interference symbol according to determination of whether the RS symbol is included in the interval including the interference symbol.

According to an embodiment, the processor calculates a first difference between the maximum value of the received power change and the minimum value of the received power change, and according to a comparison result between the first difference and a set threshold, the interference in the received signal. You can determine whether a symbol exists or not.

According to an embodiment, the processor determines that the interference symbol is present in the received signal when the first difference is greater than the set threshold, and when the first difference is less than or equal to the set threshold, the received signal It may be determined that there is no interference symbol within.

According to an embodiment, the threshold is selected from among a received power distribution of the received signal, a signal to noise ratio (SNR) for a reference signal (RS) symbol included in the received signal, and noise and interference (NI) of the RS symbol. It can be determined based on at least one.

According to an embodiment, the processor calculates a second difference between the maximum value of the received power variation and the average received power of a demodulation reference signal (DMRS) symbol included in the received signal, and calculates the second difference between the second difference and a set threshold. According to a comparison result between the signals, it may be determined whether or not the interference symbol is present in the received signal.

According to an embodiment, the processor detects two changing points at which the slope of the received power change amount changes within the slot, and corresponds to a first changing point having a large absolute value among the two changing points. A section including the interference symbol may be detected using a first code and a second code corresponding to a second change point having a smaller absolute value among the two change points.

According to an embodiment, when the first code and the second code are different, the processor determines a first section between the first change point and the second change point as a section including the interference symbol, and When the first code and the second code are the same and the first code is a positive number, a second section to the left of the first change point is determined as a section including the interference symbol, and the first code and the second code are If they are identical and the first code is a negative number, a third section to the right of the first change point may be determined as a section including the interference symbol.

According to an embodiment, the processor may set a parameter of the MMSE covariance matrix based on an indicator of the RS symbol according to determining that the RS symbol is included in a period including the interference symbol.

According to an embodiment, the processor may cancel interference with the received signal based on determining whether the RS symbol is included in a period including the interference symbol.

Claims (20)

calculating an amount of change in received power between OFDM symbols corresponding to a received signal within a slot;
determining whether there is an interference symbol in the received signal based on the amount of change in received power between the OFDM symbols;
detecting a section including the interference symbol within the slot according to a determination that the interference symbol exists;
determining whether a reference signal (RS) symbol is included in a section including the interference symbol; and
Determining a minimum mean squared error (MMSE) covariance matrix corresponding to the interference symbol according to the determination of whether the RS symbol is included in the interval including the interference symbol
Including, communication method. According to claim 1,
The operation of calculating the amount of change in the received power
calculating first average received powers of the OFDM symbols in units of subcarriers;
calculating a second average received power of all OFDM symbols included in the slot; and
Calculating the received power variation between the first average received powers and the second average received power
Including, communication method. According to claim 1,
The operation of determining whether there is the interference symbol is
calculating a first difference between the maximum value of the received power variation and the minimum value of the received power variation; and
An operation of determining whether the interference symbol is present in the received signal according to a comparison result between the first difference and a set threshold.
Including, communication method. According to claim 3,
The operation of determining whether there is the interference symbol is
determining that the interference symbol is present in the received signal when the first difference is greater than the set threshold; and
When the first difference is less than or equal to the set threshold, determining that the interference symbol is not present in the received signal.
Including, communication method. According to claim 3,
The threshold is
Communication determined based on at least one of a reception power distribution of the received signal, a signal to noise ratio (SNR) for a reference signal (RS) symbol included in the received signal, and noise and interference (NI) of the RS symbol. method. According to claim 1,
The operation of determining whether there is the interference symbol is
calculating a second difference between a maximum value of the received power variation and an average received power of a demodulation reference signal (DMRS) symbol included in the received signal; and
An operation of determining whether or not the interference symbol is present in the received signal according to a comparison result between the second difference and a set threshold.
Including, communication method. According to claim 1,
The operation of detecting a section including the interference symbol is
detecting two changing points at which a slope of the amount of change in received power changes within the slot; and
A section including the interference symbol using a first code corresponding to a first change point having a large absolute value among the two change points and a second code corresponding to a second change point having a small absolute value among the two change points. operation to detect
Including, communication method. According to claim 7,
The operation of detecting a section including the interference symbol is
determining a first section between the first change point and the second change point as a section including the interference symbol when the first code and the second code are different;
determining a second section to the left of the first change point as a section including the interference symbol when the first code and the second code are the same and the first code is a positive number; and
When the first code and the second code are the same and the first code is a negative number, determining a third section to the right of the first change point as a section including the interference symbol.
A communication method comprising at least one of According to claim 1,
The operation of determining the MMSE covariance matrix is
When the RS symbol is included in the interval including the interference symbol, setting parameters of the MMSE covariance matrix based on the indicator of the RS symbol
Including, communication method. According to claim 1,
Offsetting interference with respect to the received signal based on determining whether the RS symbol is included in a period including the interference symbol
Further comprising, a communication method. A computer program stored in a computer-readable recording medium to execute the method of any one of claims 1 to 10 in combination with hardware. An amount of change in received power between OFDM symbols corresponding to a received signal within a slot is calculated, based on the amount of change in received power between the OFDM symbols, it is determined whether or not an interference symbol exists in the received signal, and it is determined that the interference symbol exists. According to, detecting a section including the interference symbol in the slot, determining whether or not a reference signal (RS) symbol is included in a section including the interference symbol, and determining whether or not a reference signal (RS) symbol is included in a section including the interference symbol. A processor for determining an MMSE covariance matrix corresponding to the interfering symbol according to the determination of whether the symbol is included.
Including, communication device. According to claim 12,
The processor
Calculate a first difference between the maximum value of the received power change amount and the minimum value of the received power change amount;
and determining whether or not the interference symbol is present in the received signal according to a comparison result between the first difference and a set threshold. According to claim 13,
The processor
When the first difference is greater than the set threshold, determining that the interference symbol exists in the received signal;
and determining that the interference symbol is not present in the received signal when the first difference is less than or equal to the set threshold. According to claim 13,
The threshold is
Communication determined based on at least one of a reception power distribution of the received signal, a signal to noise ratio (SNR) for a reference signal (RS) symbol included in the received signal, and noise and interference (NI) of the RS symbol. Device. According to claim 12,
The processor
Calculate a second difference between the maximum value of the received power variation and the average received power of a demodulation reference signal (DMRS) symbol included in the received signal;
and determining whether or not the interference symbol is present in the received signal according to a comparison result between the second difference difference and a set threshold. According to claim 12,
The processor
detecting two changing points at which a slope of the received power change amount changes within the slot;
A section including the interference symbol using a first code corresponding to a first change point having a large absolute value among the two change points and a second code corresponding to a second change point having a small absolute value among the two change points. A communication device that detects. According to claim 17,
The processor
When the first code and the second code are different, determining a first section between the first change point and the second change point as a section including the interference symbol;
When the first code and the second code are the same and the first code is a positive number, a second section to the left of the first change point is determined as a section including the interference symbol;
When the first code and the second code are the same and the first code is a negative number, determining a third section to the right of the first change point as a section including the interference symbol. According to claim 12,
The processor
Wherein the communication device sets a parameter of the MMSE covariance matrix based on an indicator of the RS symbol according to a determination that the RS symbol is included in a period including the interference symbol. According to claim 12,
The processor
and canceling interference with the received signal based on determining whether the RS symbol is included in a period including the interference symbol.

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