# US 2019/0320429 A1 · Ue discovery method and system in d2d network > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0320429 A1 - Document ID: US20190320429A1 - Status: Published application - Kind: A1 - Application number: 16/454,656 - Filed: 2019-06-27 - Published: 2019-10-17 - Earliest claimed: 2015-02-06 - Assignees: Samsung Electronics Co., Ltd. - Applicants: Samsung Electronics Co., Ltd. - Inventors: Peng XUE; Hyun-Seok RYU; Seung-Hoon PARK; Sang-Won CHOI - Web page: https://patentgrep.com/patent/US20190320429A1 ## CPC - H04W 72/51: based on terminal or device properties - H04W 8/005: {Discovery of network devices, e.g. terminals} - H04W 48/08: Access restriction or access information delivery, e.g. discovery data delivery (signalling during connection H04W76/00) - H04W 56/00: Synchronisation arrangements - H04W 56/001: {Synchronization between nodes} - H04W 72/0446: Resources in time domain, e.g. slots or frames - H04W 72/0453: Resources in frequency domain, e.g. a carrier in FDMA - H04W 76/14: Direct-mode setup - H04W 72/02: Selection of wireless resources by user or terminal - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract A 5G or pre-5G communication system for supporting a higher data transmission rate beyond a 4G communication system such as long-term evolution (LTE) is provided, including a method for performing device to device (D2D) discovery by a user equipment (UE), which is out of the coverage area serviced by a base station, in a wireless communication network. The method includes the operations of receiving pre-configuration information for transmitting a discovery message, and transmitting the discovery message in a transmission resource determined on the basis of the pre-configuration information, wherein the pre-configuration information includes a list of pools for transmitting the discovery message, and the transmission resource is determined from the list of pools. ## Claims ### Claim 1 A method of a user equipment (UE) in a wireless communication network, the method comprising: selecting a synchronization reference UE; identifying pre-configuration information for transmitting a synchronization signal; and transmitting the synchronization signal in a subframe selected based on the pre-configuration information, wherein the pre-configuration information comprises a list of resource pools for a sidelink communication. ### Claim 2 (depends on 1) The method of claim 1, wherein the synchronization signal includes a sidelink synchronization signal (SLSS). ### Claim 3 (depends on 1) The method of claim 1, further comprising: measuring a signal from the selected synchronization reference UE; and determining whether a reference signal received power (RSRP) of the signal is less than a threshold value, wherein the threshold value is included in the pre-configuration information. ### Claim 4 (depends on 1) The method of claim 1, further comprising: transmitting system information for sidelink along with the synchronization signal for the sidelink communication in the subframe. ### Claim 5 (depends on 4) The method of claim 4, wherein the system information comprises information indicating whether the adjacent UE is inside the coverage or outside of the coverage. ### Claim 6 (depends on 1) The method of claim 1, wherein the pre-configuration information further comprises at least one of a number of times of retransmission of the synchronization signal, a number of subframe bitmaps during one discovery period, or information indicating a discovery offset. ### Claim 7 (depends on 1) The method of claim 1, further comprising: selecting SLSSID of the synchronization signal to be the same as SLSSID of the selected synchronization reference UE. ### Claim 8 (depends on 1) The method of claim 1, wherein the UE exists outside of coverage in which a service is provided by a base station. ### Claim 9 A user equipment (UE) in a wireless communication network, the UE comprising: at least one processor configured to control to: select a synchronization reference UE, identify pre-configuration information for transmitting a synchronization signal, and transmit the synchronization signal in a subframe selected based on the pre-configuration information; and a transceiver configured to transmit the synchronization signal, by a control of the at least one processor, wherein the pre-configuration information comprises a list of resource pools for a sidelink communication. ### Claim 10 (depends on 8) The UE of claim 8, wherein the synchronization signal includes a sidelink synchronization signal (SLSS). ### Claim 11 (depends on 9) The UE of claim 9, wherein the at least one processor is further configured to: measure a signal from the selected synchronization reference UE, and determine whether a reference signal received power (RSRP) of the signal is less than a threshold value, and wherein the threshold value is included in the pre-configuration information. ### Claim 12 (depends on 9) The UE of claim 9, wherein the at least one processor is further configured to transmit system information for sidelink along with the synchronization signal for the sidelink communication in the subframe. ### Claim 13 (depends on 12) The UE of claim 12, wherein the system information comprises information indicating whether the adjacent UE is inside the coverage or outside of the coverage. ### Claim 14 (depends on 9) The UE of claim 9, wherein the pre-configuration information further comprises at least one of a number of times of retransmission of the synchronization signal, a number of subframe bitmaps during one discovery period, and information indicating a discovery offset. ### Claim 15 (depends on 9) The UE of claim 9, wherein the at least one processor is configured to select SLSSID of the synchronization signal to be the same as SLSSID of the selected synchronization reference UE. ### Claim 16 (depends on 9) The UE of claim 9, wherein the UE exists outside of coverage in which a service is provided by a base station.