Field of the Invention
The present invention relates to mobile communication.
Discussion of the Related Art
3rd generation partnership project (3GPP) long term evolution (LTE) evolved from a universal mobile telecommunications system (UMTS) is introduced as the 3GPP release 8. The 3GPP LTE uses orthogonal frequency division multiple access (OFDMA) in a downlink, and uses single carrier-frequency division multiple access (SC-FDMA) in an uplink.
Recently, 3GPP LTE-A (LTE-Advanced) evolved from 3GPP LTE has been commercialized.
Meanwhile, Device-to-device (D2D) communication is a distributed communication technique in which adjacent wireless nodes directly deliver traffic. In the D2D communication, a wireless node such as a mobile phone autonomously discovers another wireless node which is physically adjacent, establishes a communication session, and thereafter transmits traffic.
D2D communication, such as Bluetooth (Bluetooth) or WiFi Direct supports direct communication between the wireless nodes without the support of the base station. Further, it is also possible that communication D2D scheduling is managed by the base station for D2D communication. Thus, D2D communication managed by the base station to spread traffic from concentrating in the base station can reduce the traffic overload problem.
The above-mentioned D2D communication can also be applied to vehicle-to-everything (V2X). V2X collectively refers to communication technology through vehicles and all interfaces. Implementations of V2X may be, for example, vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-person (V2P), vehicle-to-network (V2N), and the like.
On the other hand, since the vehicle has no restriction on the battery unlike the wireless terminal, there is a need for higher power transmission compared to the wireless terminal. Accordingly, a standard for transmitting high power in V2X communication is required.