BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to wireless communications and, more specifically, to a method of selecting a Vehicle-to-Everything (V2X) transmission resource by a user equipment (UE) in a wireless communication system and a UE using the same.

Related Art

In the International Telecommunication Union Radio Communication Sector (ITU-R), standardization of International Mobile Telecommunication (IMT)-Advanced, a next generation mobile communication system after 3rd generation, is underway. IMT-Advanced aims to support IP (Internet Protocol) based multimedia service at data rates of 1 Gbps in a stationary and low-speed moving state and 100 Mbps in a high-speed moving state.

The 3rd Generation Partnership Project (3GPP) is a system standard that meets the requirements of IMT-Advanced, and LTE-Advanced (LTE-A), which has improved Long Term Evolution (LTE) based on Orthogonal Frequency Division Multiple Access (OFDMA)/Single Carrier-LTE-Advanced (LTE-A), is being prepared. LTE-A is one of the strong candidates for IMT-Advanced.

Recently, there has been a growing interest in D2D (Device-to-Device) technology for direct communication between devices. In particular, D2D is attracting attention as a communication technology for the public safety network. Commercial communication networks are rapidly changing to LTE, but current public safety networks are mainly based on 2G technology in terms of conflicts with existing communication standards and cost. These technological gaps and demands for improved services have led to efforts to improve public safety networks.

Public safety networks have higher service requirements (reliability and security) than commercial communication networks and require direct signal transmission and reception, or D2D operation, between devices, especially when the coverage of cellular communications is insufficient or unavailable.

For example, D2D operation in general can have a variety of advantages in that it transmits and receives signals between nearby devices. For example, the D2D UE has high data rate and low delay and is capable of data communication. Also, the D2D operation can disperse the traffic to the base station, and can also expand the coverage of the base station if the UE performing the D2D operation acts as a repeater.

The D2D communication may expand and be applicable for signal transmission and reception between vehicles, and vehicle-related communication is referred to as Vehicle-To-Everything (V2X) communication.

The term “x” in V2X means pedestrian (communication between a vehicle and a device carried by an individual (e.g.) handheld terminal carried by a pedestrian, cyclist, driver or passenger)) (V2P), vehicle (communication between vehicles) (V2V), infrastructure/network (communication between a vehicle and a roadside unit (RSU)/network (e.g.) RSU is a transportation infrastructure entity (e.g.) an entity transmitting speed notifications) implemented in an eNB or a stationary UE)) (V2I/N

A (V2P communication-related) device carried by a pedestrian (or human) will be referred to as “P-UE”, and a (V2X-communication-related) device installed at a vehicle will be referred to as “V-UE”. In addition, for example, the term “entity” in the present invention may be understood as a P-UE and/or a V-UE and/or RSU (network/infrastructure).

Meanwhile, in V2X communication, the question may be which resource to be selected when a P-UE transmits a V2X signal. The P-UE is sensitive to battery consumption, compared with a UE installed at a vehicle. In addition, in 2X communication, it may be important to periodically transmit a signal without interfering other UEs. A method for selecting a transmission resource by a P-UE needs to be determined in consideration of the above.

SUMMARY OF THE INVENTION

The present invention provides a V2X transmission resource selecting method implemented by a terminal in a wireless communication system, and a terminal using the same.

In an aspect, a Vehicle-to-X (V2X) operation method implemented by a V2X User Equipment (UE) in a wireless communication system is provided. The method may comprise when a V2X transmission operation and a wide area network (WAN) transmission operation overlap in a time domain, determine whether or not the V2X transmission operation and the WAN transmission operation are performed on a same carrier and perform the V2X transmission operation on the basis of the determination, if the V2X transmission operation and the WAN transmission operation are performed on different carriers, the V2X transmission operation is performed on the basis of transmission power applied to the V2X transmission operation, or, if the V2X transmission operation and the WAN transmission operation are performed on the same carrier, the V2X transmission operation may be performed on the basis of a priority applied to the V2X transmission operation.

If the V2X transmission operation and the WAN transmission operation are performed on the different carriers, the UE may first allocate transmission power to the V2X transmission operation and then allocate remaining power transmission power to the WAN transmission operation.

If the V2X transmission operation and the WAN transmission operation are performed on the different carriers and a ProSe prioiry per packet (PPPP) of a V2X message transmitted in the V2X transmission operation is greater than a threshold value, the UE may first allocate transmission power to the V2X transmission operation.

If the V2X transmission operation and the WAN transmission operation are performed on the different carriers and a PPPP of a V2X message transmitted in the V2X transmission operation is smaller than a threshold value, the UE may first allocate transmission power to the WAN transmission operation.

If the V2X transmission operation and the WAN transmission operation are performed on the different carriers and a PPPP of a V2X message transmitted in the V2X transmission operation is greater than a threshold value, the UE may allocate transmission power only to the V2X transmission operation and omits allocating transmission power to the WAN transmission operation.

If the V2X transmission operation and the WAN transmission operation are performed on the different carriers and a PPPP of a V2X message transmitted in the V2X transmission operation is smaller than a threshold value, the UE may allocate transmission power only to the WAN transmission operation and omits allocating transmission power to the V2X transmission operation.

If the V2X transmission operation and the WAN transmission operation are performed on the same carrier, the UE may always prioritize the V2X transmission operation.

If the V2X transmission operation and the WAN transmission operation are performed on the same carrier and a PPPP of a V2X message transmitted in the V2X transmission operation is greater than a threshold value, the UE may prioritize the V2X transmission operation.

If the V2X transmission operation and the WAN transmission operation are performed on the same carrier and a PPPP of a V2X message transmitted in the V2X transmission operation is smaller than a threshold value, the UE may prioritize the WAN transmission operation.

In another aspect, a User Equipment (UE) is provided. The UE may comprise a Radio Frequency (RF) unit configured to transmit and receive a radio signal and a processor configured to operate in conjunction with the RF unit, wherein, if a Vehicle-to-X (V2X) transmission operation and a wide area network (WAN) transmission operation overlap in a time domain, the processor determines whether or not the V2X transmission operation and the WAN transmission operation are performed on a same carrier; and wherein, if the V2X transmission operation and the WAN transmission operation are performed on different carriers, the V2X transmission operation is performed on the basis of transmission power applied to the V2X transmission operation or, if the V2X transmission operation and the WAN transmission operation are performed on the same carrier, the V2X transmission operation is performed on the basis of a priority applied to the V2X transmission operation.

According to the present invention, a P-UE which is sensitive to battery consumption performs partial sensing to select a V2X transmission resource, thereby enabled to reduce battery consumption. In addition, If V2X transmission resources are selected multiple times, resources as the same as previously selected resources are excluded from the selection, and therefore, it is possible to alleviate a half-duplex problem.

