TECHNICAL FIELD

The present disclosure relates to a wireless communication system supporting device-to-device (D2D) communication, and more particularly, to a method by which a terminal transmits a D2D signal in a wireless communication system supporting D2D communication and apparatus therefor.

BACKGROUND ART

Wireless communication systems have been widely deployed to provide various types of communication services such as voice or data. In general, a wireless communication system is a multiple access system that supports communication of multiple users by sharing available system resources (a bandwidth, transmission power, etc.) among them. For example, multiple access systems include a code division multiple access (CDMA) system, a frequency division multiple access (FDMA) system, a time division multiple access (TDMA) system, an orthogonal frequency division multiple access (OFDMA) system, a single carrier frequency division multiple access (SC-FDMA) system, and a multi-carrier frequency division multiple access (MC-FDMA) system.

Device-to-device (D2D) communication is a communication scheme in which a direct link is established between user equipments (UEs) and the UEs exchange voice and data directly without intervention of an evolved Node B (eNB). D2D communication may cover UE-to-UE communication and peer-to-peer communication. In addition, D2D communication may be applied to machine-to-machine (M2M) communication and machine type communication (MTC).

D2D communication is under consideration as a solution to the overhead of an eNB caused by rapidly increasing data traffic. For example, since devices exchange data directly with each other without intervention of an eNB by D2D communication, compared to legacy wireless communication, network overhead may be reduced. Further, it is expected that the introduction of D2D communication will reduce procedures of an eNB, reduce the power consumption of devices participating in D2D communication, increase data transmission rates, increase the accommodation capability of a network, distribute load, and extend cell coverage.

At present, vehicle-to-everything (V2X) communication in conjunction with D2D communication is under consideration. In concept, V2X communication covers vehicle-to-vehicle (V2V) communication, vehicle-to-pedestrian (V2P) communication for communication between a vehicle and a different kind of terminal, and vehicle-to-infrastructure (V21) communication for communication between a vehicle and a roadside unit (RSU).

DISCLOSURE

Technical Problem

The object of the present disclosure is to provide a method by which a user equipment (UE) measures a technology congestion level based on the ratio of UEs that use (or do not use) a new ratio technology to UEs in the vicinity thereof and determine, based on the measured technology congestion level, whether to transmit a signal by applying the new radio technology in order to minimize interference and performance degradation of UEs that use other radio technologies different from the new radio technology.

It will be appreciated by persons skilled in the art that the objects that could be achieved with the present disclosure are not limited to what has been particularly described hereinabove and the above and other objects that the present disclosure could achieve will be more clearly understood from the following detailed description.

Technical Solution

In an aspect of the present disclosure, provided is a method of transmitting a device-to-device (D2D) signal by a user equipment (UE) in a wireless communication system supporting D2D communication. The method may include measuring a technology congestion level for a predetermined resource region, determining a radio technology to be applied to D2D signal transmission based on the technology congestion level, and transmitting the D2D signal based on the determined radio technology. The technology congestion level may be related to a ratio of how many times a signal including information on use of a specific radio technology is received in the predetermined resource region.

When the specific radio technology is a first radio technology, if the technology congestion level is greater than or equal to a predetermined threshold, the first radio technology may be determined as the radio technology to be applied to the D2D signal transmission.

When the specific radio technology is a second radio technology, if the technology congestion level is less than the predetermined threshold, the first radio technology may be determined as the radio technology to be applied to the D2D signal transmission.

The first radio technology may be a radio technology related to transmit diversity (TxD), multi-layer transmission, or 64 quadrature amplitude modulation (64-QAM).

The information on the use of the specific radio technology may be obtained based on properties of the signal.

The properties of the signal may include at least one of a CP length, a sequence, and a demodulation reference signal (DMRS) allocated for the signal.

The signal may include indication information indicating a radio technology applied to the signal, and the information on the use of the specific radio technology may be obtained based on the indication information included in the signal.

The information on the use of the specific radio technology may be obtained based on a priority level related to the signal.

The predetermined resource region may be a resource region to which resources for a control signal are allocated.

The technology congestion level may be related to a ratio of control signals including the information on the use of the specific radio technology to control signals received in the predetermined resource region for a predetermined time.

The signal including the information on the use of the specific radio technology may be a signal having received strength greater than or equal to a predetermined threshold.

The technology congestion level may be related to a ratio of subchannels on which the signal including the information on the use of the specific radio technology is received to a plurality of subchannels included in the predetermined resource region.

The method may further include measuring a channel busy ratio (CBR) corresponding to a channel occupation ratio based on strength of a signal received in the predetermined resource region. In this case, the technology congestion level may be calculated in consideration of the ratio of how many times the signal including the information on the use of the specific radio technology is received in the predetermined resource region and the measured CBR.

In another aspect of the present disclosure, provided is a method of controlling, by a base station, D2D signal transmission at a user equipment (UE) in a wireless communication system supporting D2D communication. The method may include receiving information on a technology congestion level for a predetermined resource region from at least one UE, determining, based on the technology congestion level, whether D2D signal transmission to which a first radio technology is applied is allowed, and transmitting, to the at least one UE, information on whether the D2D signal transmission to which the first radio technology is applied is allowed. The technology congestion level may be related to a ratio of how many times a signal including information on use of the first radio technology is received in the predetermined resource region.

The base station may determine whether the D2D signal transmission to which the first radio technology is applied is allowed for each area based on geographical information about the at least one UE, which is received from the at least one UE, and the information on the technology congestion level.

Advantageous Effects

According to the present disclosure, a user equipment (UE) may measure a technology congestion level based on the ratio of UEs that use (or do not use) a new ratio technology to UEs in the vicinity thereof and determine, based on the measured technology congestion level, whether to transmit a signal by applying the new radio technology, thereby minimizing interference and performance degradation of UEs that use other radio technologies different from the new radio technology.

Effects obtainable from the present disclosure are non-limited by the above-mentioned effects. And, other unmentioned effects can be clearly understood from the following description by those having ordinary skill in the technical field to which the present disclosure pertains.

