# US 2014/0194115 A1 · Method for discovery in device-to-device communications and apparatus for the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0194115 A1 - Document ID: US20140194115A1 - Status: Published application - Kind: A1 - Application number: 14/149,077 - Filed: 2014-01-07 - Published: 2014-07-10 - Earliest claimed: 2013-01-08 - Assignees: Electronics and Telecommunications Research Institute - Applicants: Electronics & Telecommunications Research Institute - Inventors: Mi Jeong YANG; Soon Yong LIM; Kwang Ryul JUNG; Hyung Deug BAE; You Sun HWANG; Moon Soo JANG; Hyeong Jun PARK; Nam Hoon PARK - Web page: https://patentgrep.com/patent/US20140194115A1 ## CPC - H04W 72/044: based on the type of the allocated resource - H04W 4/023: {using mutual or relative location information between multiple location based services [LBS] targets or of distance thresholds} - H04W 4/80: Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication - H04W 8/005: {Discovery of network devices, e.g. terminals} - H04W 52/0219: {where the power saving management affects multiple terminals} - H04W 52/0229: {where the received signal is a wanted signal} - H04W 52/0241: {where no transmission is received, e.g. out of range of the transmitter} - H04W 48/14: using user query {or user detection} - Y02D 30/70: in wireless communication networks - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - Y02D: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE ## Abstract A method for discovery in device-to-device communications and an apparatus for the same are disclosed. The method performed in a device-to-device server supporting device-to-device discovery between a discovery terminal and a discoverable terminal may include receiving a device-to-device discovery participation message from the discoverable terminal, requesting a gateway to measure a proximity between the discovery terminal and the discoverable terminal, receiving a proximity measurement result from the gateway, and requesting the discovery terminal and the discoverable terminal to initiate a procedure of device-to-device discovery when the proximity measurement result satisfies a predetermined threshold. Thus, the procedure of device-to-device discovery may be performed efficiently. ## Claims ### Claim 1 A method for device-to-device discovery, performed in a device-to-device server supporting device-to-device discovery between a discovery terminal and a discoverable terminal, comprising: receiving a device-to-device discovery participation message from the discoverable terminal; requesting a gateway to measure proximity between the discovery terminal and the discoverable terminal; receiving a proximity measurement result from the gateway; and requesting the discovery terminal and the discoverable terminal to initiate a procedure of device-to-device discovery when the proximity measurement result satisfies a predetermined threshold. ### Claim 2 (depends on 1) The method for device-to-device discovery according to claim 1, further comprising allocating a physical channel for device-to-device discovery for the discovery terminal and the discoverable terminal after the requesting the discovery terminal and the discoverable terminal to initiate a procedure of device-to-device discovery. ### Claim 3 (depends on 1) The method for device-to-device discovery according to claim 1, wherein the device-to-device discovery participation message indicates that the discoverable terminal participates in the procedure of device-to-device discovery requested by the discovery terminal. ### Claim 4 (depends on 1) The method for device-to-device discovery according to claim 1, wherein the gateway is a Packet Data Network (PDN) gateway (PGW). ### Claim 5 (depends on 1) The method for device-to-device discovery according to claim 1, wherein the proximity is measured based on received signal strength of reference signals transmitted and received between the discovery terminal and the discoverable terminal. ### Claim 6 (depends on 1) The method for device-to-device discovery according to claim 1, wherein the proximity is measured based on positional information of the discovery terminal and positional information of the discoverable terminal. ### Claim 7 (depends on 1) The method for device-to-device discovery according to claim 1, wherein the predetermined threshold is determined based on a minimal distance which makes device-to-device communications between the discovery terminal and the discoverable terminal possible. ### Claim 8 A method for device-to-device discovery, performed in a device-to-device server supporting device-to-device discovery between a discovery terminal and a discoverable terminal, comprising: receiving device-to-device communication initiation request messages from the discovery terminal and the discoverable terminal; transmitting a device-to-device communication configuration request message requesting a gateway to configure device-to-device communications between the discovery terminal and the discoverable terminal; and receiving a device-to-device communication configuration response message indicating a completion of configuration of device-to-device communications between the discovery terminal and the discoverable terminal from the gateway when a proximity measurement result satisfies a predetermined threshold. ### Claim 9 (depends on 8) The method for device-to-device discovery according to claim 8, wherein the device-to-device communication initiation request messages are received from the discovery terminal which recognized the discoverable terminal and from the discoverable terminal which recognized the discovery terminal ### Claim 10 (depends on 8) The method for device-to-device discovery according to claim 8, wherein the gateway is a Packet Data Network (PDN) gateway (PGW). ### Claim 11 (depends on 8) The method for device-to-device discovery according to claim 8, wherein the device-to-device communication configuration request messages include a network identifier of the discovery terminal and a network identifier of the discoverable terminal. ### Claim 12 (depends on 8) The method for device-to-device discovery according to claim 8, wherein the proximity is measured based on received signal strength of reference signals transmitted and received between the discovery terminal and the discoverable terminal. ### Claim 13 (depends on 8) The method for device-to-device discovery according to claim 8, wherein the proximity is measured based on positional information of the discovery terminal and positional information of the discoverable terminal. ### Claim 14 (depends on 8) The method for device-to-device discovery according to claim 8, wherein the predetermined threshold is determined based on a minimal distance which makes device-to-device communications between the discovery terminal and the discoverable terminal possible. ### Claim 15 A method for measuring proximity between terminals, performed in a base station, comprising: allocating radio resources for transmitting a reference signal for measuring proximity to a first terminal; allocating radio resources for receiving the reference signal for measuring proximity to a second terminal; obtaining information on measurement result of the reference signal from the second terminal; and determining whether to start device-to-device communications between the first terminal and the second terminal based on the information on measurement result of the reference signal. ### Claim 16 (depends on 15) The method for measuring proximity between terminals according to the claim 15, wherein the base station allocates radio resources for transmitting the reference signal for measuring proximity based on a request of a device-to-device server. ### Claim 17 (depends on 15) The method for measuring proximity between terminals according to the claim 15, wherein the information on measurement result of the reference signal includes the received signal strength of the reference signal. ### Claim 18 (depends on 17) The method for measuring proximity between terminals according to the claim 17, wherein the device-to-device communications between the first terminal and the second terminal are determined to be started when the received signal strength of the reference signal is equal to or above a predetermined threshold. ### Claim 19 (depends on 17) The method for measuring proximity between terminals according to the claim 17, wherein the device-to-device communications between the first terminal and the second terminal are determined to be released when the received signal strength of the reference signal is below a predetermined threshold. ### Claim 20 (depends on 18) The method for measuring proximity between terminals according to the claim 18, wherein the predetermined threshold is a minimal signal strength which makes the device-to-device communications between the first terminal and the second terminal possible.