# US 10,485,038 B2 · Method and device for device to device communication > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,485,038 B2 - Document ID: US10485038B2 - Status: Granted - Kind: B2 - Application number: 15/505,912 - Filed: 2016-06-10 - Published: 2018-08-02 - Granted: 2019-11-19 - Earliest claimed: 2015-06-10 - Assignees: Samsung Electronics Co., Ltd. - Applicants: Samsung Electronics Co., Ltd. - Inventors: Anil Agiwal; June Hwang; Hyun-Seok Ryu; Young-Bin Chang - Web page: https://patentgrep.com/patent/US10485038B2 ## CPC - H04W 76/14: Direct-mode setup - H04W 8/005: {Discovery of network devices, e.g. terminals} - H04W 24/08: Testing, {supervising or monitoring} using real traffic - H04W 76/10: Connection setup - H04W 88/04: adapted for relaying to or from another terminal or user - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract The present disclosure relates to a 5G or pre-5G communication system for supporting a higher data transmission rate than a 4G communication system such as LTE. The method for device to device communication according to the present disclosure comprises: a step of receiving, by a terminal, search data from search resources for relay search within a specified search-receiving resource pool, and decoding the same; a step of measuring, by the terminal, link qualities of the search resources which deliver demodulation reference signals, from the search resources corresponding to successfully decoded search data; and a step of filtering a link quality corresponding to an identifier of a specific relay among the measured link qualities. ## Claims ### Claim 1 A method of device to device direct communication, the method comprising: receiving, by a user equipment (UE), one or more discovery messages on a physical sidelink discovery channel (PSDCH) for relay related discovery; identifying an identifier (ID) of a relay UE that transmits a discovery message of the one or more discovery messages, wherein the discovery message is a discovery announcement message; generating, by the UE, a reference signal received power (RSRP) measurement associated with the identified ID of the relay UE by measuring power of resource elements carrying demodulation reference signals (DMRSs) corresponding to the PDSCH on which the discovery message is received, if the discovery message is passed through cyclic redundancy check (CRC); filtering, by the UE, RSRP measurements corresponding to a same ID among RSRP measurements corresponding to the one or more discovery messages; and selecting a relay UE among relay UES corresponding to the one or more discovery messages based on the filtered RSRP measurements. ### Claim 2 (depends on 1) The method of claim 1, wherein decoding the discovery message for the CRC and generating the RSRP measurement are performed by a physical layer within the UE, and wherein filtering the RSRP measurements is performed by a radio resource control (RRC) layer within the UE. ### Claim 3 (depends on 2) The method of claim 2, wherein the physical layer generates the RSRP measurement based on a measurement instruction of the RRC layer. ### Claim 4 (depends on 1) The method of claim 1, wherein identifying the ID of the relay UE is performed by a higher layer within the UE, and the identified ID of the relay UE is transferred by the higher layer to a radio resource control (RRC) layer within the UE. ### Claim 5 (depends on 4) The method of claim 4, wherein the higher layer comprises a medium access control (MAC) layer and a proximity service (ProSe) protocol layer. ### Claim 6 (depends on 5) The method of claim 5, wherein the MAC layer transmits the discovery message and the RSRP measurements to the ProSe protocol layer. ### Claim 7 (depends on 1) The method of claim 1, wherein a proximity service (ProSe) protocol layer determines whether the discovery message is the discovery announcement message. ### Claim 8 A user equipment (UE) apparatus for device to device direct communication, the UE apparatus comprising: a transceiver configured to: perform a device to device direct communication through a direct communication path; and a controller configured to: receive one or more discovery messages on a physical sidelink discovery channel (PSDCH) for relay related discovery, identify an identifier (ID) of a relay UE that transmits a discovery message of the one or more discovery messages, wherein the discovery message is a discovery announcement message, generate a reference signal received power (RSRP) measurement associated with the identified ID of the relay UE by measuring power of resource elements carrying demodulation reference signals (DMRSs) corresponding to the PDSCH on which the discovery message is received, if the discovery message is passed through cyclic redundancy check (CRC), filter RSRP measurements corresponding to a same ID among RSRP measurements corresponding to the one or more discovery messages; and select a relay UE among relay UEs corresponding to the one or more discovery messages based on the filtered RSRP measurements. ### Claim 9 (depends on 8) The UE apparatus of claim 8, wherein the controller is further configured to include a physical layer and a radio resource control (RRC) layer, wherein the physical layer receives and decodes the discovery message for the CRC and generates the RSRP measurement, and wherein the RRC layer filters the RSRP measurements. ### Claim 10 (depends on 9) The UE apparatus of claim 9, wherein the physical layer generates the RSRP measurement based on a measurement instruction of the RRC layer. ### Claim 11 (depends on 8) The UE apparatus of claim 8, wherein the controller is further configured to include a higher layer and a radio resource control (RRC) layer, and wherein the higher layer identifies the ID of the relay UE and transfers the identified ID of the relay UE to the RRC layer. ### Claim 12 (depends on 11) The UE apparatus of claim 11, wherein the higher layer comprises a medium access control (MAC) layer and a proximity service (ProSe) protocol layer. ### Claim 13 (depends on 12) The UE apparatus of claim 12, wherein the MAC layer transmits the discovery message and the RSRP measurements to the ProSe protocol layer. ### Claim 14 (depends on 8) The UE apparatus of claim 8, wherein a proximity service (ProSe) protocol layer determines whether the discovery message is the discovery announcement message.