BACKGROUNDS

Field of the Disclosure

The present disclosure relates to wireless communication and, more particularly, to a method for transmitting an uplink signal in a wireless communication system and a terminal using the same method.

Related Art

As more and more communication devices require more communication capacity, there is a need for improved mobile broadband communication over existing radio access technology. Also, massive machine type communications (MTC), which provides various services by connecting many devices and objects, is one of the major issues to be considered in the next generation communication.

In addition, communication system design considering reliability/latency sensitive service/UE is being discussed. The introduction of next generation radio access technology considering enhanced mobile broadband communication (eMBB), massive MTC (mMTC), ultrareliable and low latency communication (URLLC) is discussed. This new technology may be called new radio access technology (new RAT or NR) in the present disclosure for convenience.

In future wireless communication systems such as the NR, the introduction of a scheme for greatly reducing a transmission delay depending on the application field is considered. In particular, in uplink (UL) transmission, instead of UL transmission according to an existing UL grant-based scheduling, the introduction of grant-free UL transmission in which uplink transmission is started by determination of a terminal is also considered.

However, there may be some problems in grant-free UL transmission.

First, even if grant-free UL transmission is configured, the UE does not perform UL transmission without a grant when there is no uplink data to be actually transmitted. In this case, there may be a problem that it is ambiguous for the base station as to whether UL transmission is properly configured in the UE.

Second, a plurality of resource sets that can be used for UL transmission without grant may be configured, and activation/deactivation of grant-free UL transmission may be performed by one-time signaling. In this case, there may be a problem that it is ambiguous as to which resource set of the plurality of resource sets is used for grant-free UL transmission.

Third, in the case where a plurality of resource sets that can be used for grant-free UL transmission is configured through a higher layer signal such as a radio resource control (RRC) signal, when it is necessary to change the resource sets because the amount of uplink traffic/characteristics is changed, an RRC configuration process may be necessary. At this point, inconsistency between the terminal and the base station may occur regarding which resource set is used to perform grant-free UL transmission in the RRC resetting process.

There is a need for a method and an apparatus that can solve the aforementioned problems.

SUMMARY

The present disclosure provides a method for transmitting an uplink signal of a terminal in a wireless communication system, and a terminal using the same method.

In one aspect, a method for transmitting an uplink (UL) signal of a terminal in a wireless communication system is provided. The method comprises receiving activation information for activating or deactivating a specific resource set from among a plurality of resource sets; and when the activation information activates the specific resource set, performing grant-free UL transmission using a resource belonging to the specific resource set.

The activation information may be received through downlink control information (DCI).

The activation information may comprise an identity (ID) of the specific resource set.

The UL transmission may be a transmission of a physical uplink shared channel (PUSCH).

The grant-free UL transmission may be transmitting, by the terminal, the PUSCH using any of resources belonging to the specific resource set without a UL grant for scheduling the PUSCH.

A response to the activation information may be transmitted by the terminal.

An acknowledgement to the activation information may be transmitted as the response.

A sounding reference signal (SRS) may be transmitted as the response.

Channel state information (CSI) may be transmitted as the response.

A physical random access channel (PRACH) may be transmitted as the response.

The plurality of resource sets may be configured by a radio resource control (RRC) signal.

At least one resource set from among the plurality of resource sets may be used for a fallback operation in an RRC reconfiguration period.

A physical layer signal indicating use of the at least one resource set may be further received.

The activation information may use a scrambling or cyclic redundancy check (CRC) masking sequence specific to the specific resource set.

In another aspect, provided is a terminal, comprising a transceiver configured to transmit and receive a radio signal; and a processor configured to operate with being connected to the transceiver, wherein the processor is further configured to receive activation information for activating or deactivating a specific resource set from among a plurality of resource sets, and, when the activation information activates the specific resource set, perform grant-free uplink (UL) transmission using a resource belonging to the specific resource set.

Since a response to a signal for setting (activating/deactivating) the grant-free UL transmission is transmitted, ambiguity is reduced as to whether or not the grant-free UL transmission is set. In addition, a signal for setting (activating/deactivating) grant-free UL transmission indicates which resource set among resource sets that can be used for grant-free UL transmission, thereby reducing ambiguity as to a resource used for grant-free UL transmission. In addition, when a plurality of resource sets that can be used for grant-free UL transmission is configured through a higher layer signal such as a radio resource control (RRC) signal, a resource set used for a fallback operation is introduced/used in an RRC reconfiguration period, thereby reducing ambiguity as to a resource set to be used in the RRC reconfiguration period.

