KR102340271B1 - Rediction-based full duplex harq communication method and wireless communication system using the same - Google Patents

Abstract

In the prediction-based full-duplex HARQ communication method according to an embodiment of the present invention, in the prediction-based full-duplex HARQ communication method of a wireless communication system supporting a full duplex system, data is allocated to a PDCCH and the data is transmitted transmitting on FDSCH; transmitting, by the FDSCH receiving the data, a mutual signal to the PHICH of the base station and the PUCCH of the terminal; after transmitting the mutual signal, comparing the SINR of the received data with a preset threshold; and determining whether to perform retransmission by predicting ACK and NACK based on the comparison result.

Description

Prediction-based full duplex HARQ communication method and wireless communication system using the same

The present invention relates to a wireless communication system, and more particularly, to a prediction-based HARQ communication method in a system supporting FULL DUPLEX and a wireless communication system using the same.

Among the techniques for increasing the reliability of wireless communication, there is an automatic repeat request (ARQ). In ARQ, when the receiving end fails to receive the data signal, the transmitter retransmits the data signal. In addition, there is also a hybrid automatic repeat request (HARQ) combining FEC (Forward Error Correction) and ARQ. The receiving end using HARQ basically attempts error correction on the received data signal, and determines whether to retransmit using an error detection code. The error detection code may use CRC (Cyclic Redundancy Check). If an error of the data signal is not detected through the CRC detection process, the receiving end determines that decoding of the data signal is successful. In this case, the receiving end transmits an ACK (acknowledgment) signal to the transmitter. When an error of the data signal is detected through the CRC detection process, the receiving end determines that decoding of the data signal has failed. In this case, the receiving end sends a NACK (Not-Acknowledgment) signal to the transmitter. The transmitter may retransmit the data signal when the NACK is received.

The present invention may provide a prediction-based full-duplex HARQ communication method for determining whether to operate prediction-based full-duplex HARQ communication based on a threshold suitable for a communication environment, and a wireless communication system using the same.

The problems of the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

A prediction-based full-duplex HARQ communication method for solving the above technical problem includes: allocating data to a PDCCH and transmitting the data to an FDSCH; transmitting, by the FDSCH receiving the data, a mutual signal to the PHICH of the base station and the PUCCH of the terminal; after transmitting the mutual signal, comparing the SINR of the received data with a preset threshold; and determining whether to perform retransmission by predicting ACK and NACK based on the comparison result.

According to an embodiment, the step of determining whether to perform retransmission by predicting ACK and NACK based on the comparison result may include predicting ACK and not performing retransmission when the SINR of the received data is higher than a preset threshold value. may include

According to an embodiment, the step of predicting whether to perform retransmission by predicting ACK and NACK based on the comparison result may include, if the SINR of the received data is lower than a preset threshold, predicting NACK and performing retransmission immediately may include

According to an embodiment, when the SINR of the received data is lower than a preset threshold, the step of immediately performing retransmission by predicting NACK may include allocating data used for retransmission through the PDCCH.

According to an embodiment, each of the terminal and the base station receiving a mutual signal and determining whether to ACK or NACK based on a CRC result; and when the CRC result is ACK, the terminal transmits the ACK through the PUCCH, and the base station transmits the ACK through the PHICH.

According to an embodiment, when the NACK occurs in only one of the terminal or the base station, the method may further include determining whether there is data to be transmitted to the terminal.

According to an embodiment, when there is information data to be transmitted in the queue, the method may further include transmitting the information data and retransmission data in full duplex.

According to an embodiment, when there is no information data to be transmitted in the queue, the method may further include transmitting retransmission data and an arbitrary busy tone in full duplex.

According to an embodiment, when the CRC result is NACK, the method may further include the step of transmitting the NACK through the PUCCH by the UE and transmitting the NACK through the PHICH by the base station.

According to an embodiment, when the terminal and the base station receive a NACK, performing data allocation through the PDCCH; and performing retransmission on the FDSCH in response to the data allocation.

The prediction-based full-duplex HARQ communication method according to the present invention and a wireless communication system using the same have the effect of improving the retransmission delay time by acquiring channel information using the characteristics of full-duplex communication and predicting whether to retransmit based on this. have.

The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those of ordinary skill in the art to which the present invention belongs from the following description. will be.

1 is a diagram illustrating a communication device according to an embodiment of the present invention.
2 to 3 are diagrams illustrating a 3GPP standard-based NACK operation according to a conventional half-duplex system.
4 to 6 are diagrams illustrating a prediction-based full duplex HARQ communication method according to a full duplex system according to the present invention.
7 is a diagram illustrating an ACK operation flow of a full duplex system according to a full duplex system according to an embodiment of the present invention.
8 is a diagram illustrating a flow of a prediction-based retransmission operation according to a full duplex system according to an embodiment of the present invention.

Hereinafter, an apparatus and various methods to which embodiments of the present invention are applied may be described in more detail with reference to the drawings. The suffixes "module" and "part" for components used in the following description are given or mixed in consideration of only the ease of writing the specification, and do not have distinct meanings or roles by themselves.

In the above, even though all the components constituting the embodiment of the present invention are described as being combined or operated in combination, the present invention is not necessarily limited to this embodiment. That is, within the scope of the object of the present invention, all the components may operate by selectively combining one or more. In addition, although all the components may be implemented as one independent hardware, some or all of the components are selectively combined to perform some or all of the functions of the combined hardware in one or a plurality of hardware program modules It may be implemented as a computer program having Codes and code segments constituting the computer program can be easily inferred by those skilled in the art of the present invention. Such a computer program is stored in a computer readable storage medium (Computer Readable Media), read and executed by the computer, thereby implementing the embodiment of the present invention. The storage medium of the computer program may include a magnetic recording medium, an optical recording medium, a carrier wave medium, and the like.

In the description of the embodiment, in the case of being described as being formed in "above (above) or below (below)", "before (front) or after (rear)" of each component, "above (above) or below" "(below)" and "before (front) or after (behind)" may include both components in which two components are in direct contact with each other or one or more other components are disposed between the two components. .

In addition, terms such as "comprises", "comprises" or "have" described above mean that the corresponding component may be embedded, unless otherwise specified, excluding other components. Rather, it may be construed as being capable of including other components further. All terms, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs, unless otherwise defined. Terms commonly used, such as those defined in the dictionary, should be interpreted as being consistent with the meaning of the context of the related art, and are not interpreted in an ideal or excessively formal meaning unless explicitly defined in the present invention.

In addition, in describing the components of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the elements from other elements, and the essence, order, or order of the elements are not limited by the terms. When it is described that a component is “connected”, “coupled” or “connected” to another component, the component may be directly connected or connected to the other component, but another component is between each component. It should be understood that elements may also be “connected,” “coupled,” or “connected.”

And, in the description of the present invention, if it is determined that the subject matter of the present invention is unnecessarily obscured as it is obvious to those skilled in the art with respect to related known techniques, the detailed description thereof may be omitted.

1 is a diagram illustrating a wireless communication system to which the present invention is applied.

Referring to FIG. 1 , a wireless communication system is widely deployed to provide various communication services such as voice and packet data. A wireless communication system includes a base station (eNode B: eNB, 10) and a terminal (UE: User Equipment, 20).

The base station 10 may be referred to by other terms such as a base transceiver system (BTS), an access point, a femto base station, a home nodeB, and a relay.

The base station may simultaneously transmit multiple data streams for a broadcast service, a multicast service, and/or a unicast service. In this case, the base station may control data transmission/reception for a plurality of terminals.

For downlink (DL) data, the base station transmits downlink scheduling information and informs the corresponding terminal of the time/frequency domain in which data will be transmitted, encoding, data size, hybrid automatic repeat and request (HARQ) related information, and the like.

For uplink (UL) data, the base station transmits uplink scheduling information to the corresponding terminal to inform the terminal of the time/frequency domain, encoding, data size, HARQ-related information, etc. that the terminal can use.

The terminal 20 may be fixed or mobile, and may include a mobile station (MS), a mobile terminal (MT), a user terminal (UT), a subscriber station (SS), a wireless device, a personal digital assistant (PDA), It may be called by other terms such as a wireless modem, a handheld device, and the like.

The terminal 20 receives information from the base station through downlink (DL), and the terminal 20 transmits information to the base station through uplink (UL). Information transmitted/received between the base station and the terminal includes data and various control information, and various physical channels exist according to the type/use of the information they transmit/receive.

For uplink transmission and downlink transmission, a method of transmitting/receiving a signal in a half-duplex method and a method of transmitting/receiving a signal in a full-duplex method may be used.

Hereinafter, downlink means communication from the base station 10 to the terminal 20 , and uplink means communication from the terminal 20 to the base station 10 . The downlink transmitting end may be the transmitting end 11 of the base station 10 , and the downlink receiving end may be the receiving end 22 of the terminal 20 . The uplink transmitting end may be the transmitting end 21 of the terminal 20 , and the uplink receiving end may be the receiving end 11 of the base station 10 .

2 to 3 are diagrams illustrating a 3GPP standard-based NACK operation according to a conventional half-duplex system.

Referring to FIG. 2, in the downlink NACK operation of the half-duplex system, when data to be transmitted through a physical downlink control channel (PDCCH) is allocated, a signal is transmitted from the base station 10 to the terminal 20 through a physical downlink shared channel (PDSCH). do.

The terminal 20 may determine whether ACK (Acknowledge) or NACK (Negative Acknowledge) is based on a cyclic redundancy check (CRC) result and transmit the NACK through a Physical Uplink Control Channel (PUCCH).

Thereafter, when the base station 10 receives the retransmitted signal, it can receive an error-free signal together with the first received signal through a code-based reception technique.

In this case, in the 3GPP LTE standard operation, 3 ms (= 3TTI) may be required for each processing delay of the terminal 20 and the base station 10 .

Here, a transmission time interval (TTI) is a time it takes to transmit a subframe for uplink/downlink data packet transmission in a half-duplex system and a full-duplex system. For example, the length of one subframe may be 1 ms.

Referring to FIG. 3 , in the uplink NACK operation of the half-duplex system, when data to be transmitted through the PDCCH is allocated, a signal is transmitted from the terminal 20 to the base station 10 through a physical uplink shared channel (PUSCH).

Thereafter, the base station 10 may determine whether to ACK or NACK based on the CRC result and transmit the NACK through a Physical Hybrid ARQ Indicator Channel (PHICH). In this case, the PHICH transmits HARQ information to inform the UE whether ACK or NACK should be retransmitted.

When the terminal 20 receives the retransmitted signal, it can receive an error-free signal together with the first received signal through a code-based reception technique.

Accordingly, the retransmission delay time according to the NACK operation of the half-duplex system according to FIGS. 2 to 3 may lead to the sum of the UE processing delay, the NACK transmission time, the eNB processing delay, and the retransmission time. The UE processing delay corresponds to the second to fourth subframes, the NACK transmission signal corresponds to the fifth subframe, the eNB processing delay corresponds to the sixth to eighth subframes, and the retransmission signal corresponds to the ninth subframe. can do. That is, a total delay time of 8TTI (8ms) may occur.

4 to 6 are diagrams illustrating a prediction-based full duplex HARQ communication method according to a full duplex system according to the present invention.

A full duplex system according to the present invention may include a Full Duplex Shared Channel (FDSCH) for simultaneously performing transmission and reception.

Referring to FIG. 4 , in the ACK operation of the full duplex system, when data is allocated in full duplex through the PDCCH, mutual signals are transmitted to the terminal 20 and the base station 10 through the FDSCH, respectively. In this case, the processing delay of the terminal 20 and the base station 10 takes 3 ms (= 3TTI).

Thereafter, the terminal 20 and the base station 10 may determine whether to ACK or NACK based on the CRC result.

When the CRC result is ACK, the UE may transmit ACK through PUCCH, and the base station may transmit ACK through PHICH.

Therefore, in the NACK operation of the full duplex system according to FIG. 4 , the PDCCH allocates data to the first subframe, and the FDSCH receiving it allocates data after the UE response, and the mutual signal corresponds to the fifth subframe. have.

Thereafter, UE processing delay and eNB processing delay may be allocated to 6th to 8th, respectively, so that PHICH may correspond to ACK in the ninth subframe, and PUCCH may correspond to ACK to ninth subframe.

)은 하기 수학식 1을 만족하는 값일 수 있다.Referring to FIG. 5 , in the prediction-based retransmission operation of the full duplex system, after each of the terminal 20 and the base station transmits a mutual signal on the FDSCH, SINR (Signal to Interference plus Noise Ratio) of the received data and a preset threshold may be compared. At this time, the threshold (

) may be a value satisfying Equation 1 below.

[Equation 1]

은 BLER(Block Error Rate)을 의미할 수 있다. SNIR 대비 BLER의 그래프는 MCS(Modulation Coding Scheme)값이 정해지면 결정되는 함수로 제안 기법의 동작을 위해서는 모든 MCS값에 대해서 임계값(threshold)을 미리 구해서 table로 가질 수 있다.here

may mean BLER (Block Error Rate). The graph of BLER versus SNIR is a function that is determined when an MCS (Modulation Coding Scheme) value is determined. For the operation of the proposed method, thresholds for all MCS values can be obtained in advance and stored in a table.

Thereafter, it is possible to determine whether to perform retransmission by predicting ACK and NACK based on the comparison result.

As a result of the comparison, when the SINR is higher than a preset threshold, retransmission is not performed by predicting an ACK.

On the other hand, after each of the terminal 20 and the base station 10 of the full duplex system transmits a mutual signal on the FDSCH, the SINR of the received data is lower than a preset threshold, NACK Retransmission can be performed immediately by predicting. In this case, data used for retransmission is allocated through the PDCCH.

Accordingly, the retransmission signal may correspond to the sixth subframe by the prediction-based retransmission delay time (prediction & retransmission) according to the NACK operation of the full duplex system. In this case, the delay time according to the retransmission may occur as a delay time of 1 TTI (1 ms) for the retransmission. That is, compared to the retransmission operation according to the retransmission delay time of the conventional half-duplex system, the prediction retransmission operation can be performed 7TTI faster.

Therefore, the full duplex system retransmission operation reduces the processing delay of the terminal 20 receiving end and the base station 10 receiving end, the NACK transmission time, and the processing delay after the NACK reception of the terminal 20 transmitting end and the base station 10 transmitting end to reduce the retransmission delay time. can have the effect of reducing

And, when NACK occurs only in one of the terminal 20 or the base station 10, if there is information data to be transmitted in the queue, the corresponding information data and retransmission data may be transmitted in full duplex.

In addition, when NACK occurs only in one of the terminal 20 or the base station 10 , if there is no information data to be transmitted in the queue, retransmission data and an arbitrary busy tone may be transmitted together.

Referring to FIG. 6, when the NACK prediction of the terminal 20 and the base station 10 is wrong, the full duplex system does not need retransmission, so 1TTI, which is the prediction-based retransmission time, is wasted, but the signal is an error can be received without

In addition, when the ACK predictions of the terminal 20 and the base station 10 are wrong, if the retransmission is not performed because actual retransmission is required, a CRC result error may occur. Therefore, in order to receive without error, a NACK operation is performed.

When the CRC result of the receiving end is NACK, the terminal 20 may transmit the NACK through the PUCCH and the base station 10 may transmit the NACK through the PHICH. When the terminal and the base station receive the NACK, data allocation may be performed through the PDCCH and retransmission may be performed on the FDSCH in response to the data allocation.

At this time, 3 ms (= 3TTI) is required for the processing delay of the terminal 20 and the base station 10, respectively, and the NACK transmission and retransmission by the terminal 20 and the base station 10 takes 1 ms (= 1 TTI) do.

The retransmission delay time according to the NACK operation of the full duplex system may lead to the sum of the UE processing delay, the NACK transmission time, the eNB processing delay, and the retransmission time. The UE processing delay corresponds to the second to fourth subframes, the NACK transmission signal corresponds to the fifth subframe, the eNB processing delay corresponds to the sixth to eighth subframes, and the retransmission signal corresponds to the ninth subframe. can do. That is, a total delay time of 8TTI (8ms) may occur.

7 is a diagram illustrating an ACK operation flow of a full duplex system according to a full duplex system according to an embodiment of the present invention.

Referring to FIG. 7 , when the ACK operation of a full duplex system is described, full duplex data is allocated through the PDDCH (S110).

After the step S110, the FDSCH transmits a mutual signal corresponding to the data to be used to the PHICH of the base station 10 and the PUCCH of the terminal 20, respectively (S120).

After the step S120, the receiving end of each of the base station 10 and the terminal 20 may determine whether to ACK or NACK based on the CRC (S130).

After the step S130, the UE may transmit the ACK through the PUCCH and the eNB may transmit the ACK through the PHICH (S140).

8 is a diagram illustrating a flow of a prediction-based retransmission operation according to a full duplex system according to an embodiment of the present invention.

Referring to FIG. 8, when the FDSCH of FIG. 7 transmits a mutual signal corresponding to the data to be used to the PHICH of the base station 10 and the PUCCH of the terminal 20, respectively (S120), the base station 10 and the terminal ( 20) Each receiving end may determine whether the SINR of the received data is equal to or greater than a preset threshold (S210).

After the step S210, the receiving end of each of the base station 10 and the terminal 20 may not perform retransmission by predicting an ACK when the SINR of the received data is higher than a pre-calculated threshold (S215).

On the other hand, after the step S210, when the SINR of the received data is lower than the preset threshold value, the receiving end of each of the base station 10 and the terminal 20 may predict NACK and perform retransmission immediately (S220).

After step S220, it may be determined whether NACK has occurred in only one of the base station 10 or the terminal 20 (S230).

After step S230, if only one of the base station 10 or the terminal 20 has a NACK, it may be determined whether there is data to be transmitted in the queue (S240).

After step S240, if there is data to be transmitted in the queue, data to be transmitted and retransmission data may be transmitted in full duplex (S245).

In addition, when there is no data to be transmitted in the queue after step S240, retransmission data and an arbitrary busy tone may be transmitted together in full duplex (S250).

The method according to the above embodiment may be produced as a program to be executed on a computer and stored in a computer-readable recording medium, and examples of the computer-readable recording medium include ROM, RAM, CD ROM, magnetic tape, Also included are those implemented in the form of a floppy disk, an optical data storage device, or the like.

The computer-readable recording medium is distributed in a network-connected computer system, so that the computer-readable code can be stored and executed in a distributed manner. In addition, functional programs, codes, and code segments for implementing the above-described method can be easily inferred by programmers in the technical field to which the embodiment belongs.

It is apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit and essential characteristics of the present invention.

Accordingly, the above detailed description should not be construed as restrictive in all respects but as exemplary. The scope of the present invention should be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the present invention are included in the scope of the present invention.

10: base station
20: terminal

Claims (23)

In the prediction-based full duplex HARQ communication method of a wireless communication system supporting a full duplex system,
allocating data to a PDCCH and transmitting the data to an FDSCH;
transmitting, by the FDSCH receiving the data, mutual signals simultaneously to the PHICH of the base station and the PUCCH of the terminal;
after transmitting the mutual signal, comparing the SINR of the received data with a preset threshold; and
and determining whether to perform retransmission by predicting ACK and NACK based on the comparison result
Prediction-based full duplex HARQ communication method. The method of claim 1,
The preset threshold (

) is calculated as follows,

stands for BLER (Block Error Rate).
Prediction-based full duplex HARQ communication method. 3. The method of claim 2,
The step of determining whether to perform retransmission by predicting ACK and NACK based on the comparison result
When the SINR of the received data is higher than a preset threshold, predicting an ACK and not performing retransmission
Prediction-based full duplex HARQ communication method. 3. The method of claim 2,
Determining whether to perform retransmission by predicting ACK and NACK based on the comparison result
When the SINR of the received data is lower than a preset threshold, predicting NACK and performing retransmission immediately
Prediction-based full duplex HARQ communication method. 5. The method of claim 4,
If the SINR of the received data is lower than a preset threshold, predicting NACK and performing retransmission immediately includes:
Allocating data used for retransmission through the PDCCH
Prediction-based full duplex HARQ communication method. The method of claim 1,
determining whether to ACK or NACK based on a CRC result by receiving a mutual signal by each of the terminal and the base station; and
When the CRC result is ACK, the terminal transmits ACK through PUCCH, and the base station transmits ACK through PHICH
Prediction-based full duplex HARQ communication method. 7. The method of claim 6,
Further comprising the step of determining whether there is data to be transmitted to the terminal when only one of the terminal or the base station has a NACK
Prediction-based full duplex HARQ communication method. 8. The method of claim 7,
When there is information data to be transmitted in the queue, transmitting the information data and retransmission data in full duplex; further comprising
Prediction-based full duplex HARQ communication method. 8. The method of claim 7,
If there is no information data to be transmitted in the queue, further comprising the step of transmitting retransmission data and any busy tone in full duplex
Prediction-based full duplex HARQ communication method. 7. The method of claim 6,
When the CRC result is NACK, the terminal transmits NACK through PUCCH, and the base station further comprises the step of transmitting NACK through PHICH
Prediction-based full duplex HARQ communication method. 11. The method of claim 10,
performing data allocation through the PDCCH when the terminal and the base station receive the NACK; and
Further comprising the step of performing retransmission in the FDSCH in response to the data allocation
Prediction-based full duplex HARQ communication method. A computer-readable recording medium in which a program for executing the method according to any one of claims 1 to 11 is recorded. In a wireless communication system including a base station and a terminal for simultaneously performing an uplink signal and a downlink signal by supporting a full duplex system,
Data is allocated to the PDCCH and the data is transmitted to the FDSCH,
The FDSCH receiving the data simultaneously transmits a mutual signal to the PHICH of the base station and the PUCCH of the terminal,
After transmitting the mutual signal, comparing the SINR of the received data with a preset threshold,
Determining whether to perform retransmission by predicting ACK and NACK based on the comparison result
wireless communication system. 14. The method of claim 13,
The preset threshold (

) is calculated as follows,

stands for BLER (Block Error Rate).
wireless communication system. 15. The method of claim 14,
The wireless communication system is
When the SINR of the received data is higher than a preset threshold, predicting an ACK and not performing retransmission
wireless communication system. 15. The method of claim 14,
The wireless communication system is
When the SINR of the received data is lower than a preset threshold, predicting NACK and performing retransmission immediately
wireless communication system. 17. The method of claim 16,
The wireless communication system is
When the SINR of the received data is lower than a preset threshold value, when retransmission is immediately performed by predicting NACK, data used for retransmission is allocated through the PDCCH.
wireless communication system. 14. The method of claim 13,
The wireless communication system is
The terminal and the base station each receive a mutual signal and determine whether to ACK or NACK based on the CRC result,
When the CRC result is ACK, the terminal transmits ACK through PUCCH, and the base station transmits ACK through PHICH
wireless communication system. 19. The method of claim 18,
The wireless communication system is
When NACK occurs in only one of the terminal or the base station, determining whether there is data to be transmitted to the terminal
wireless communication system. 20. The method of claim 19,
The wireless communication system is
When there is information data to be transmitted in the queue, the information data and retransmission data are transmitted in full duplex.
wireless communication system. 20. The method of claim 19,
The wireless communication system is
If there is no information data to be sent in the queue, retransmission data and any busy tones are sent in full duplex.
wireless communication system. 19. The method of claim 18,
The wireless communication system is
When the CRC result is NACK, the terminal transmits NACK through PUCCH, and the base station transmits NACK through PHICH
wireless communication system. 23. The method of claim 22,
The wireless communication system is
When the terminal and the base station receive the NACK, data allocation through the PDCCH is performed, and retransmission is performed on the FDSCH in response to the data allocation.
wireless communication system.

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