KR20200112014A - Method and apparatus for transmitting mac control information in communication system - Google Patents

Abstract

Disclosed are a method for transmitting MAC control information in a communication system and an apparatus thereof. According to the present invention, an operation method of a first communication node may comprise the steps of: allocating a first resource for transmission of a first response signal to a first signal to a second communication node; transmitting the first signal to the second communication node; receiving a second response signal for the first signal from the second communication node in a second resource; and retransmitting the first signal to the second communication node if the first response signal for the first signal is not received from the first resource from the second communication node within a preset time. Therefore, reliable and rapid transmission and reception of MAC control information may be possible.

Description

MAC control information transmission method and apparatus in a communication system {METHOD AND APPARATUS FOR TRANSMITTING MAC CONTROL INFORMATION IN COMMUNICATION SYSTEM}

The present invention relates to a method and apparatus for transmitting MAC control information in a communication system, and more particularly, to a method for increasing the reliability of transmission of MAC control information.

Mobile communication up to the previous generation has mainly evolved in the direction of increasing wireless data rates in mobile environments. On the other hand, next-generation mobile communication is evolving in a direction to provide a wireless connection capable of providing various application services that could not be supported by the existing network as well as the continuous increase in communication speed. In addition to the existing high-speed wireless data service (enhanced mobile broadband (eMBB)), regional monitoring, massive machine type communication (mMTC), industrial automation, vehicle-to-vehicle communication, etc. Complex application services of required ultra-reliable low latency communication (URLLC) will also be provided through next-generation mobile communication. In order to provide such a service, the mobile communication system defines various performance requirements and adds various protocol functions to satisfy them.

For a negative acknowledgment (NACK)-to-ACK (acknowledgement) error, the UE receives data that is a cyclic redundancy check (CRC) error and transmits hybrid automatic repeat request (HARQ) NACK information in the uplink, but the base station HARQ HARQ NACK. It may be an error recognized as ACK. In this case, the base station may recognize that the UE has normally received a MAC CE (MAC control element), and the MAC CE to be transmitted to the UE may be lost. Therefore, reliable transmission of MAC CE may be required.

An object of the present invention for solving the above problems is to provide a method for increasing the reliability of transmission of MAC control information in a communication system.

In order to achieve the above object, a method of operating a first communication node in a communication system according to an embodiment of the present invention includes allocating a first resource for transmission of a first response signal to a first signal to a second communication node. Steps, transmitting the first signal to the second communication node, receiving a second response signal for the first signal from the second communication node from a second resource, and the second communication within a preset time And retransmitting the first signal to the second communication node when the first response signal to the first signal is not received from the first resource from the node, and the first signal at the second communication node If is successfully decoded, the first response signal is transmitted from the second communication node, and if decoding of the first signal fails in the second communication node, the first response signal may not be transmitted from the second communication node. I can.

According to the present invention, the base station may request an acknowledgment (ACK) for receiving the MAC control information from the terminal when a reliable response to the reception of MAC control information is required. Upon receiving the MAC control information, the UE may transmit a separate ACK to the base station in addition to the hybrid automatic repeat request (HARQ) ACK. In addition, the base station may allocate uplink resources for MAC control information ACK to the terminal when a quick response to the MAC control information is required. The UE may transmit the MAC control information ACK through the allocated uplink resource. Therefore, reliable and rapid transmission and reception of MAC control information may be possible. Therefore, the performance of the communication system can be improved.

1 is a conceptual diagram showing an embodiment of a communication system.
2 is a block diagram showing a first embodiment of a communication node constituting a communication system.
3 is a flowchart illustrating an embodiment of a case in which transmission of MAC control information has failed.
4 is a flowchart illustrating an embodiment of a method of transmitting MAC control information when a transmission failure of MAC control information and a HARQ NACK-to-ACK error occur.
5 is a flowchart illustrating an embodiment of a method of transmitting RLC data and MAC control information when transmission of MAC control information fails and a HARQ NACT-to-ACK error occurs.
6 is a flowchart illustrating a method of transmitting and receiving MAC control information according to an embodiment of the present invention.
7 is a flowchart illustrating a method of transmitting and receiving MAC control information when a HARQ NACK-to-ACK error occurs according to an embodiment of the present invention.
8 is a flowchart illustrating a procedure for transmitting and receiving MAC control information of a terminal according to an embodiment of the present invention.
9 is a flowchart illustrating a procedure for transmitting and receiving MAC control information of a base station according to an embodiment of the present invention.

In the present invention, various modifications may be made and various embodiments may be provided, and specific embodiments will be illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to a specific embodiment, it is to be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention.

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

When a component is referred to as being "connected" or "connected" to another component, it is understood that it may be directly connected or connected to the other component, but other components may exist in the middle. Should be. On the other hand, when a component is referred to as being "directly connected" or "directly connected" to another component, it should be understood that there is no other component in the middle.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, but one or more other features. It is to be understood that the presence or addition of elements or numbers, steps, actions, components, parts, or combinations thereof, does not preclude in advance.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms as defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in the present application. Does not.

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

A communication system to which embodiments according to the present invention are applied will be described. The communication system to which the embodiments according to the present invention are applied is not limited to the contents described below, and the embodiments according to the present invention can be applied to various communication systems. Here, the communication system may be used with the same meaning as a communication network.

1 is a conceptual diagram showing a first embodiment of a communication system.

Referring to FIG. 1, a communication system 100 includes a plurality of communication nodes 110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, 130-4, 130-5, 130-6). In addition, the communication system 100 includes a core network (eg, a serving-gateway (S-GW), a packet data network (PDN)-gateway), and a mobility management entity (MME)). It may contain more.

The plurality of communication nodes may support 4G communication (eg, long term evolution (LTE), LTE-A (advanced)), 5G communication, and the like specified in the 3rd generation partnership project (3GPP) standard. 4G communication may be performed in a frequency band of 6 GHz or less, and 5G communication may be performed in a frequency band of 6 GHz or more as well as a frequency band of 6 GHz or less. For example, for 4G communication and 5G communication, a plurality of communication nodes may include a code division multiple access (CDMA)-based communication protocol, a wideband CDMA (WCDMA)-based communication protocol, a time division multiple access (TDMA)-based communication protocol, Frequency division multiple access (FDMA)-based communication protocol, OFDM (orthogonal frequency division multiplexing)-based communication protocol, Filtered OFDM-based communication protocol, CP (cyclic prefix)-OFDM-based communication protocol, DFT-s-OFDM (discrete) Fourier transform-spread-OFDM) based communication protocol, OFDMA (orthogonal frequency division multiple access) based communication protocol, SC (single carrier)-FDMA based communication protocol, NOMA (non-orthogonal multiple access), GFDM (generalized frequency) Division multiplexing)-based communication protocol, filter bank multi-carrier (FBMC)-based communication protocol, universal filtered multi-carrier (UFMC)-based communication protocol, and space division multiple access (SDMA)-based communication protocol can be supported. . Each of the plurality of communication nodes may have the following structure.

2 is a block diagram showing a first embodiment of a communication node constituting a communication system.

Referring to FIG. 2, the communication node 200 may include at least one processor 210, a memory 220, and a transmission/reception device 230 connected to a network to perform communication. In addition, the communication node 200 may further include an input interface device 240, an output interface device 250, and a storage device 260. Each of the components included in the communication node 200 may be connected by a bus 270 to perform communication with each other.

However, each of the components included in the communication node 200 may be connected through an individual interface or an individual bus centering on the processor 210 instead of the common bus 270. For example, the processor 210 may be connected to at least one of the memory 220, the transmission/reception device 230, the input interface device 240, the output interface device 250, and the storage device 260 through a dedicated interface. .

The processor 210 may execute a program command stored in at least one of the memory 220 and the storage device 260. The processor 210 may mean a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to embodiments of the present invention are performed. Each of the memory 220 and the storage device 260 may be configured with at least one of a volatile storage medium and a nonvolatile storage medium. For example, the memory 220 may be formed of at least one of a read only memory (ROM) and a random access memory (RAM).

Referring back to FIG. 1, the communication system 100 includes a plurality of base stations 110-1, 110-2, 110-3, 120-1, 120-2, and a plurality of terminals 130- 1, 130-2, 130-3, 130-4, 130-5, 130-6). Base stations (110-1, 110-2, 110-3, 120-1, 120-2) and terminals (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) The containing communication system 100 may be referred to as an “access network”. Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 may form a macro cell. Each of the fourth base station 120-1 and the fifth base station 120-2 may form a small cell. The fourth base station 120-1, the third terminal 130-3, and the fourth terminal 130-4 may belong to the cell coverage of the first base station 110-1. The second terminal 130-2, the fourth terminal 130-4, and the fifth terminal 130-5 may belong to the cell coverage of the second base station 110-2. The fifth base station 120-2, the fourth terminal 130-4, the fifth terminal 130-5, and the sixth terminal 130-6 may belong within the cell coverage of the third base station 110-3. have. The first terminal 130-1 may belong to the cell coverage of the fourth base station 120-1. The sixth terminal 130-6 may belong to the cell coverage of the fifth base station 120-2.

Here, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 is a NodeB, an evolved NodeB, gNB, ng-eNB, and BTS (base transceiver station), radio base station, radio transceiver, access point, access node, road side unit (RSU), radio remote head (RRH), TP ( transmission point), transmission and reception point (TRP), and may be referred to as f (flexible)-TRP. Each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 is a user equipment (UE), a terminal, an access terminal, and a mobile device. Mobile terminal, station, subscriber station, mobile station, portable subscriber station, node, device, internet of things (IoT) It may be referred to as a device supporting a function, a mounted module/device/terminal, an on board unit (OBU), or the like.

Meanwhile, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may operate in different frequency bands or may operate in the same frequency band. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be connected to each other through an ideal backhaul link or a non-ideal backhaul link, , Information can be exchanged with each other through an ideal backhaul link or a non-ideal backhaul link. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be connected to the core network through an ideal backhaul link or a non-ideal backhaul link. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 transmits a signal received from the core network to the corresponding terminal 130-1, 130-2, 130-3, 130 -4, 130-5, 130-6), and the signal received from the corresponding terminal (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) Can be transferred to.

In addition, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 transmits MIMO (e.g., single user (SU)-MIMO, multi-user (MU)- MIMO, massive MIMO, etc.), coordinated multipoint (CoMP) transmission, carrier aggregation (CA) transmission, transmission in an unlicensed band, direct communication between terminals (device to device communication, D2D) (or, ProSe ( proximity services)). Here, each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 is a base station 110-1, 110-2, 110-3, 120-1 , 120-2) and operations supported by the base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be performed. For example, the second base station 110-2 may transmit a signal to the fourth terminal 130-4 based on the SU-MIMO scheme, and the fourth terminal 130-4 may transmit a signal to the fourth terminal 130-4 by the SU-MIMO scheme. A signal may be received from the second base station 110-2. Alternatively, the second base station 110-2 may transmit a signal to the fourth terminal 130-4 and the fifth terminal 130-5 based on the MU-MIMO method, and the fourth terminal 130-4 And each of the fifth terminal 130-5 may receive a signal from the second base station 110-2 by the MU-MIMO method.

Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 may transmit a signal to the fourth terminal 130-4 based on the CoMP scheme, and The terminal 130-4 may receive signals from the first base station 110-1, the second base station 110-2, and the third base station 110-3 by the CoMP method. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 has terminals 130-1, 130-2, 130-3, and 130-4 belonging to their cell coverage. , 130-5, 130-6) and the CA method can transmit and receive signals.

3 is a flowchart illustrating an embodiment of a case in which transmission of MAC control information has failed.

Referring to FIG. 3, the communication system of FIG. 3 may be the same as or similar to the communication system of FIG. 1. The terminal 300 of FIG. 3 may be the communication nodes 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 of FIG. 1. The base station 310 of FIG. 3 may be the communication nodes 110-1, 110-2, and 110-3 of FIG. 1. The terminal 300 and the base station 310 may perform communication based on a communication protocol (eg, 4G communication protocol, 5G communication protocol).

The base station 310 may need to transmit MAC control information to the terminal 300 for reasons such as a scheduling result. When there is no data transmission requirement from an upper layer (eg, a radio link control (RLC) layer), the base station 410 may generate MAC control information including only a MAC CE (MAC control element) (S301). . The base station 310 may transmit the generated MAC control information to the terminal 300 (S302).

The terminal 300 may receive MAC control information from the base station 310. The terminal 300 may perform a cyclic redundancy check (CRC) on the received MAC control information. When a CRC error does not occur, the terminal 300 may transmit a hybrid automatic repeat and request acknowledgment (ACK) to the base station 310. The base station 310 can receive the HARQ ACK from the terminal 300, and it can be seen that transmission of MAC control information has been successful.

When a CRC error occurs, the terminal 300 may transmit a HARQ NACK (negative ACK) to the base station 310 (S303). The base station 310 can receive the HARQ NACK from the terminal 300, and it can be seen that transmission of MAC control information has failed. In this case, the base station 310 may retransmit the same MAC control information as the previously transmitted MAC control information (S304). The terminal 300 may receive the MAC control information retransmitted from the base station 310. The terminal 300 may perform CRC of the received MAC control information. If the CRC error has not occurred, the terminal 300 may transmit a HARQ ACK to the base station 310 (S305). The base station 310 can receive the HARQ ACK from the terminal 300, and it can be seen that retransmission of the MAC control information is successful.

4 is a flowchart illustrating an embodiment of a method of transmitting MAC control information when a transmission failure of MAC control information and a HARQ NACK-to-ACK error occur.

Referring to FIG. 4, the communication system of FIG. 4 may be the same as or similar to the communication system of FIG. 3. The terminal 400 of FIG. 4 may be the terminal 300 of FIG. 3, and the base station 410 of FIG. 4 may be the base station 310 of FIG. 3.

The base station 410 may have to transmit the MAC control information to the terminal 400 for reasons such as a scheduling result. When there is no data transmission requirement from an upper layer (eg, an RLC layer), the base station 410 may generate MAC control information including only the MAC CE (S401). The base station 410 may transmit the generated MAC control information to the terminal 400 (S402).

The terminal 400 may receive MAC control information from the base station 410. The terminal 400 may perform CRC on the received MAC control information. When a CRC error occurs, the terminal 400 may transmit HARQ NACK to the base station 410 (S403). However, when an error occurs in HARQ NACK transmission, the base station 410 may recognize this as HARQ ACK even though the terminal 400 transmits the HARQ NACK (S404). This is called HARQ NACK-to-ACK error.

When a HARQ NACK-to-ACK error occurs, the base station 410 may determine that the terminal 400 has successfully received the MAC control information even though the terminal 400 has not received the MAC control information. Therefore, the base station 410 may not perform retransmission of the MAC control information even if the terminal 400 fails to receive the MAC control information. Accordingly, MAC control information to be transmitted to the terminal 400 may be lost.

FIG. 5 is a flowchart illustrating an embodiment of a method of transmitting RLC data and MAC control information when transmission of MAC control information fails and a HARQ NACK-to-ACK error occurs.

Referring to FIG. 5, the communication system of FIG. 5 may be the same as or similar to the communication system of FIG. 3. The terminal 500 of FIG. 5 may be the terminal 300 of FIG. 3, and the base station 410 of FIG. 5 may be the base station 310 of FIG. 3.

The base station 510 may need to transmit MAC control information to the terminal 500 for reasons such as scheduling results. If there is a data transmission requirement from the RLC layer, the base station 510 may generate RLC data and MAC control information (S501). The base station 510 may transmit the generated RLC data and MAC control information to the terminal 500 (S502).

The terminal 500 may receive RLC data and MAC control information from the base station 510. The terminal 500 may perform CRC on the received RLC data and MAC control information. When a CRC error occurs, the terminal 500 may transmit a HARQ NACK to the base station 510 (S503). However, when an error occurs in HARQ NACK transmission, the base station 510 may recognize this as HARQ ACK even though the terminal 500 transmits the HARQ NACK (S504).

If a HARQ NACK-to-ACK error occurs, the base station 510 may determine that the terminal 500 has successfully received the MAC control information even though the terminal 500 has not received the MAC control information. Accordingly, the base station 510 may not perform retransmission of the MAC control information even though the terminal 500 has failed to receive the MAC control information. Accordingly, MAC control information to be transmitted to the terminal 500 may be lost.

On the other hand, if the base station 510 does not receive the RLC ARQ ACK for a preset time after transmitting the RLC data, it can regenerate the RLC data (S505) and retransmit the generated RLC data to the terminal 500. Yes (S506). The terminal 500 may receive the retransmitted RLC data from the base station 510. The terminal 500 may perform CRC on the received RLC data. If no CRC error has occurred, the terminal 500 may transmit a HARQ ACK to the base station 510 (S507). If no CRC error has occurred, the RLC data may be delivered to the RLC layer of the terminal 500. Accordingly, the terminal 500 may transmit an RLC ACK to the base station 510 (S508).

The base station 510 may receive a HARQ ACK from the terminal 500. In addition, the base station 510 may receive an RLC ACK from the terminal 500. When the base station 510 receives the RLC ACK from the terminal 500 within a preset time, the base station 510 may not retransmit the RLC data. In this case, although the terminal 500 has received RLC data, there may be a problem in that the terminal 500 cannot receive MAC control information related to the RLC data. Hereinafter, a procedure for transmitting and receiving MAC control information for preventing loss of MAC control information due to a HARQ NACK-to-ACK error will be described.

6 is a flowchart illustrating a method of transmitting and receiving MAC control information according to an embodiment of the present invention.

Referring to FIG. 6, the communication system of FIG. 6 may be the same as or similar to the communication system of FIG. 3. The terminal 600 of FIG. 6 may be the terminal 300 of FIG. 3, and the base station 610 of FIG. 6 may be the base station 310 of FIG. 3.

The base station 610 may have to transmit the MAC control information to the terminal 600 for reasons such as a scheduling result. When there is no data transmission requirement from an upper layer (eg, an RLC layer), the base station 610 may generate MAC control information including only MAC CE (S601).

The base station 610 may allocate uplink resources for transmitting the MAC control information ACK to the terminal 600, and transmit the allocated uplink resource information to the terminal 600 (S602). Here, the MAC control information ACK may be a response message separate from the HARQ ACK. The terminal 600 may receive uplink resource information allocated for transmission of the MAC control information ACK from the base station 610.

The base station 610 may set a timer for the MAC control information ACK reception (S603). When the base station 610 does not receive the MAC control information ACK so that the timer expires (ie, does not receive the MAC control information ACK within a preset time), the base station 610 may retransmit the MAC control information. If the base station 610 receives the MAC control information ACK before the timer expires, the base station 610 may not retransmit the MAC control information.

The base station 610 may transmit the generated MAC control information to the terminal 600 (S604). The terminal 600 may receive MAC control information from the base station 610. The terminal 600 may perform CRC on the received MAC control information. If the CRC error does not occur, the terminal 600 may transmit a HARQ ACK to the base station 610 (S605). The base station 610 may receive the HARQ ACK from the terminal 600, and HARQ retransmission may not be performed. However, when the base station 610 receives not only the HARQ ACK but also the MAC control information ACK, it may determine that transmission of the MAC control information is successful.

When the terminal 600 successfully receives the MAC control information from the base station 610 (when the MAC control information is successfully decoded), the terminal 600 may generate the MAC control information ACK (S606). The MAC control information ACK may be generated in the MAC layer of the terminal 600. The terminal 600 may transmit the MAC control information ACK to the base station 610 by using the uplink resource allocated in S602 (S607). The base station 610 can receive the MAC control information ACK from the terminal 600, and can recognize that the terminal 600 has successfully received the MAC control information. The base station 610 may initialize the timer and terminate the MAC control information transmission/reception procedure.

7 is a flowchart illustrating a method of transmitting and receiving MAC control information when a HARQ NACK-to-ACK error occurs according to an embodiment of the present invention.

Referring to FIG. 7, the communication system of FIG. 7 may be the same as or similar to the communication system of FIG. 3. The terminal 700 of FIG. 7 may be the terminal 300 of FIG. 3, and the base station 710 of FIG. 7 may be the base station 310 of FIG. 3.

The base station 710 may have to transmit the MAC control information to the terminal 700 for reasons such as a scheduling result. If there is no data transmission requirement from an upper layer (eg, an RLC layer), the base station 710 may generate MAC control information including only MAC CE (S701).

The base station 710 may allocate an uplink resource for transmitting the MAC control information ACK to the terminal 700 and transmit the allocated uplink resource information to the terminal 700 (S702). Here, the MAC control information ACK may be a response message separate from the HARQ ACK. The terminal 700 may receive uplink resource information allocated for transmitting the MAC control information ACK from the base station 710.

The base station 710 may set a timer for the MAC control information ACK reception (S703). When the base station 710 does not receive the MAC control information ACK so that the timer expires (ie, does not receive the MAC control information ACK within a preset time), the base station 710 may retransmit the MAC control information. If the base station 710 receives the MAC control information ACK before the timer expires, the base station 710 may not retransmit the MAC control information.

The base station 710 may transmit the generated MAC control information to the terminal 700 (S704). The terminal 700 may receive MAC control information from the base station 710. The terminal 700 may perform CRC on the received MAC control information. When a CRC error occurs, the terminal 700 may transmit HARQ NACK to the base station 710 (S705). However, when an error occurs in HARQ NACK transmission, the base station 710 may recognize this as HARQ ACK even though the terminal 700 transmits the HARQ NACK (S706).

Meanwhile, since the terminal 710 has not successfully received the MAC control information (because the decoding of the MAC control information has failed), the MAC control information ACK may not be transmitted. When the base station 710 fails to receive the MAC control information ACK so that the timer set in S703 expires (S707), the base station 710 may generate the MAC control information again (S708).

The base station 710 may allocate an uplink resource for transmitting the MAC control information ACK to the terminal 700 and transmit the allocated uplink resource information to the terminal 700 (S709). The terminal 700 may receive uplink resource information allocated for transmitting the MAC control information ACK from the base station 710. The base station 710 may set a timer for the MAC control information ACK reception (S710).

The base station 710 may transmit the generated MAC control information to the terminal 700 (S711). The terminal 700 may receive MAC control information from the base station 710. The terminal 700 may perform CRC on the received MAC control information. When the CRC error does not occur, the terminal 700 may transmit a HARQ ACK to the base station 710 (S712). The base station 710 may receive the HARQ ACK from the terminal 700, and HARQ retransmission may not be performed.

When the terminal 700 successfully receives the MAC control information from the base station 710 (when the MAC control information is successfully decoded), the terminal 700 may generate the MAC control information ACK (S713). The MAC control information ACK may be generated in the MAC layer of the terminal 700. The terminal 700 may transmit the MAC control information ACK to the base station 710 by using the uplink resource allocated in S709 (S714). The base station 710 may receive the MAC control information ACK from the terminal 700 and recognize that the terminal 700 has successfully received the MAC control information. The base station 710 may initialize the timer and terminate the MAC control information transmission/reception procedure.

8 is a flowchart illustrating a procedure for transmitting and receiving MAC control information of a terminal according to an embodiment of the present invention.

Referring to FIG. 8, the MAC control information 800 received from the base station to the terminal may include information on whether a response to the reception of the MAC control information 800 is requested. When generating the MAC control information 800, the base station may include information on whether a response to the reception of the MAC control information 800 is required.

The terminal may receive the MAC control information 800 (S801). When the MAC control information is successfully decoded, the terminal 800 may check whether a response to the reception of the MAC control information 800 is required (S802). When a response to the reception of the MAC control information 800 is not required, the UE may not transmit the MAC control information ACK 810. Even in this case, HARQ ACK or NACK for MAC control information may be transmitted.

When a response to the reception of the MAC control information 800 is required, the terminal may transmit the MAC control information ACK 810 to the base station (S803). When the UE is allocated uplink resources for transmitting the MAC control information ACK 810 from the base station, the UE may transmit the MAC control information ACK 810 through the allocated uplink resource. When the UE has not been allocated uplink resources for transmission of the MAC control information ACK 810 from the base station, the UE may transmit the MAC control information ACK 810 to the base station according to a general uplink resource allocation procedure.

9 is a flowchart illustrating a procedure for transmitting and receiving MAC control information of a base station according to an embodiment of the present invention.

Referring to FIG. 9, the base station may generate MAC control information (S901). The MAC control information generated by the base station may include information on the importance of the response of the MAC control information. Specifically, when generating MAC control information, the base station may determine whether the corresponding MAC control information requires a reliable response, a quick and reliable response, or whether a response is required (S902). The base station may include information on whether a reliable response is required, a quick and reliable response is required, or a response is not required in the generated MAC control information.

When it is determined that the MAC control information does not require a separate response, the base station may transmit the MAC control information to the terminal (S903). Since the terminal does not transmit the MAC control information ACK to the base station, the base station can end the MAC control information transmission/reception procedure without waiting for the reception of the MAC control information. However, even in this case, ACK/NACK according to HARQ may be transmitted.

If it is determined that a quick and reliable response of the MAC control information is required, the base station may allocate uplink resources for MAC control information ACK transmission to the terminal (S904). In addition, the base station may operate a timer for receiving the MAC control information ACK (S905). The base station may transmit MAC control information to the terminal (S906). The base station may check whether the MAC control information ACK is received from the terminal (S907). When receiving the MAC control information ACK, the base station may initialize a timer and terminate the MAC control information transmission/reception procedure. If the base station does not receive the MAC control information ACK, it can check whether the timer set in S905 has expired (S908). When the timer has expired, the base station may operate again from step S901. That is, if the MAC control information ACK is not received within a preset time, the base station may perform the MAC control information retransmission procedure. If it is before the timer expires, the base station can check whether the MAC control information ACK is received until the timer expires. The maximum number of retransmissions may be determined according to the type of MAC control information. When the timer expires, the base station may perform a response procedure according to occurrence of a specific error situation instead of performing the MAC control information retransmission procedure.

If the base station determines that only a reliable response of the MAC control information is needed (ie, it is determined that a quick response is not required), the step of allocating an uplink resource for ACK of the MAC control information (S904) may be omitted. Accordingly, the operation of the base station may proceed directly from step S902 to step S905.

The methods according to the present invention may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like alone or in combination. The program instructions recorded on the computer-readable medium may be specially designed and configured for the present invention, or may be known and usable to those skilled in computer software.

Examples of computer-readable media include hardware devices specially configured to store and execute program instructions, such as rom, ram, flash memory, and the like. Examples of program instructions include not only machine language codes such as those produced by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The above-described hardware device may be configured to operate as at least one software module to perform the operation of the present invention, and vice versa.

Although described with reference to the above embodiments, those skilled in the art will understand that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention described in the following claims. I will be able to.

Claims (1)

As a method of operating a first communication node in a communication system,
Allocating a first resource for transmission of a first response signal to a first signal to a second communication node;
Transmitting the first signal to the second communication node;
Receiving a second response signal for the first signal from the second communication node in a second resource; And
Retransmitting the first signal to the second communication node if the first response signal for the first signal is not received from the first resource from the second communication node within a preset time,
When the first signal is successfully decoded by the second communication node, the first response signal is transmitted from the second communication node, and when decoding of the first signal fails at the second communication node, the first response signal Is not transmitted from the second communication node.

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