BACKGROUND

1. Field

Exemplary embodiments relate to wireless communication, and more particularly, to a method and apparatus for transmitting a synchronization signal for Device to Device (D2D) communication in a wireless communication system.

2. Discussion of the Background

Device to Device (D2D) communication refers to a communication scheme that executes direct data transmission and reception between neighboring two User Equipments (UEs) without an evolved NodeB (eNodeB). That is, two UEs act as a source and a destination of data, and execute communication.

The D2D communication may be executed through a communication scheme that uses a non-licensed band such as a Wireless Local Area Network (LAN), Bluetooth, or the like. However, the communication scheme using the non-licensed band may have difficulty in providing planed and controlled services. In particular, the performance may be significantly deteriorated by interference.

Conversely, D2D communication that is operated or provided in a licensed-band or in an environment where inter-system interference is controlled, may support Quality of service (QoS) and may increase frequency utilization efficiency through frequency reusing and may increase a communication distance.

In the D2D communication in the licensed band, that is, in the cellular communication based-D2D communication, an eNodeB allocates resources of a UE, and the allocated resources may use a cellular uplink channel.

The D2D communication may include intra-cell D2D communication and inter-cell D2D communication. The inter-cell D2D communication may be embodied based on cooperative communication between two eNodeBs.

Therefore, there is desire for a method for effective use of resources and allocating a synchronization signal, for D2D communication services in the recent wireless communication system.

SUMMARY

One or more exemplary embodiments provide a method and apparatus for transmitting a synchronization signal for Device to Device (D2D) communication in a wireless communication system.

One or more exemplary embodiments provide a method and apparatus for configuring a synchronization signal in a wireless communication system that supports D2D communication.

One or more exemplary embodiments provide a method and apparatus for configuring a sequence of a synchronization signal that has good correlation.

One or more exemplary embodiments provide a method of transceiving a synchronization signal by a user equipment (UE) supporting a device-to-device (D2D) communication between UEs, the method including: receiving, at a first UE, a synchronization signal transmitted from a synchronization source; determining a root index based on the received synchronization signal; determining a synchronization timing reference based on the root index; and transmitting a synchronization signal for a D2D communication based on the determined synchronization timing reference. The determining of the synchronization timing reference includes: based on the root index, determining a category of the synchronization source; prioritizing the synchronization source based on determining whether the synchronization source is an evolved NodeB (eNodeB), a UE synchronized with an eNodeB, or a UE having a synchronization timing reference independent from an eNodeB; and determining the synchronization timing reference based on the prioritization. One or more exemplary embodiments provide a method of transceiving a synchronization signal by a user equipment (UE) supporting a device-to-device (D2D) communication between UEs, the method including: receiving, at a UE, synchronization signals transmitted from different synchronization sources, respectively; prioritizing the different synchronization sources based on categories of the different synchronization sources, the categories including an evolved NodeB (eNodeB), a UE synchronized with an eNodeB, and a UE having a synchronization timing reference independent from an eNodeB; determining a reference synchronization source for the UE among the different synchronization sources; synchronizing with the reference synchronization source based on a synchronization timing reference associated with the reference synchronization source; and transmitting, from the UE, a signal based on the synchronization.

One or more exemplary embodiments provide a method of transceiving a synchronization signal by a user equipment (UE) supporting a device-to-device (D2D) communication between UEs, the method including: receiving, at a UE, synchronization signals transmitted from different synchronization sources, respectively; prioritizing the different synchronization sources based on the received synchronization signals; determining a reference synchronization source for the UE among the different synchronization sources; synchronizing with the reference synchronization source based on a synchronization timing reference associated with the reference synchronization source; and transmitting, from the UE, a signal to the reference synchronization source based on the synchronization. The determining of the reference synchronization source includes: determining a root index based on each synchronization signal received from the respective synchronization source; determining a category of the respective synchronization source based on the root index; prioritizing the different synchronization sources based on the corresponding categories; and determining the reference synchronization source based on the prioritization.

According to one or more exemplary embodiments, D2D synchronization information may be efficiently indicated based on an apparatus that transmits or receives a D2D signal. Therefore, D2D scheduling allocation (SA) and data information may be efficiently transmitted by securing efficiency of obtaining synchronization between User Equipments (UEs) inside or outside network coverage.

