# US 10,873,895 B2 · Apparatus and method for providing relay selection in device-to-device communication system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,873,895 B2 - Document ID: US10873895B2 - Status: Granted - Kind: B2 - Application number: 15/537,854 - Filed: 2015-12-21 - Published: 2017-12-14 - Granted: 2020-12-22 - Earliest claimed: 2014-12-19 - Assignees: Samsung Electronics Co., Ltd. - Applicants: Samsung Electronics Co., Ltd. - Inventors: Anil Agiwal; Manali Sharma; Nagacharan Udupi; Anshuman Nigam; Radhakrishnan Raju - Web page: https://patentgrep.com/patent/US10873895B2 ## CPC - H04W 40/22: using selective relaying for reaching a BTS [Base Transceiver Station] or an access point - H04L 5/0048: {Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091)} - H04L 5/0057: {Physical resource allocation for CQI} - H04L 27/26: Systems using multi-frequency codes (H04L27/32 takes precedence) - H04L 27/362: {Modulation using more than one carrier, e.g. with quadrature carriers, separately amplitude modulated (H04L27/366 takes precedence)} - H04W 40/12: based on transmission quality or channel quality - H04W 48/20: Selecting an access point - H04W 76/14: Direct-mode setup - H04W 8/005: {Discovery of network devices, e.g. terminals} - H04W 40/24: Connectivity information management, e.g. connectivity discovery or connectivity update - H04W 88/04: adapted for relaying to or from another terminal or user - 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) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - 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 The present disclosure relates to a pre-5th-generation (5G) or 5G communication system to be provided for supporting higher data rates beyond 4th-generation (4G) communication system such as a long term evolution (LTE). The various embodiments of the present disclosure disclose a method for selecting a relay in a source user equipment (UE) in a device-to-device (D2D) communication system. The method includes receiving a relay discovery message from one or more user equipment-network (UE-NW) relays; measuring a radio link quality of a wireless link between the source UE and a UE-NW relay for each of the one or more UE-NW relays discovered by the source UE; and selecting a UE-NW relay using information included in the relay discovery message, the radio link quality of the wireless link between the source UE and the UE-NW relay and a radio link quality of the wireless link between the UE-NW relay and a base station (BS). ## Claims ### Claim 1 A method of a user equipment (UE) in a communication system, the method comprising: receiving, from relays, relay discovery messages, each relay discovery message including a user information identifier (ID) associated with a relay among the relays and a service code used for identifying a connectivity service; identifying that the connectivity service is discovered in case that the service code included in the relay discovery message is same as a service code configured to the UE for a connectivity service authorized to be accessed by the UE, and the user information ID included in the relay discovery message is same as a user information ID configured to the UE for the relay providing the connectivity service; measuring radio qualities between the UE and the relays based on a result of the identification; and selecting one of the relays as a relay for the UE based on the measured radio qualities, wherein each of the radio qualities is a linear average over power contributions of resource elements carrying reference signals. ### Claim 2 (depends on 1) The method of claim 1, wherein selecting the one of the relays as the relay for the UE comprises: identifying candidate relays of which linear averages over power contributions of resource elements carrying the reference signals exceed a threshold by a set value among the relays; and selecting the relay for the UE among the identified candidate relays based on the measured radio qualities. ### Claim 3 (depends on 2) The method of claim 2, wherein the selected relay is a candidate relay of which a linear average is highest among the candidate relays. ### Claim 4 A method of a relay in a communication system, the method comprising: transmitting a relay discovery message including a service code used for identifying a connectivity service and a user information identifier (ID) associated with a relay among relays, and wherein the relay discovery message is associated with reference signals, wherein the connectivity service is discovered in a user equipment (UE), in case that the service code included in the relay discovery message is same as a service code configured to the UE for a connectivity service authorized to be accessed by the UE, and the user information ID included in the relay discovery message is same as a user information ID configured to the UE for the relay providing connectivity service, wherein a radio quality between the UE and the relay is measured based on the reference signals, wherein the measured radio quality is used in selection of a relay for the UE, and wherein the radio quality is a linear average over power contributions of resource elements carrying the reference signals. ### Claim 5 (depends on 4) The method of claim 4, wherein relays of which linear averages over power contributions of resource elements carrying the reference signals exceed a threshold by a set value among the relays are identified as candidate relays, and the relay is selected for the UE among the identified candidate relays based on respective measured radio qualities. ### Claim 6 (depends on 5) The method of claim 5, wherein the selected relay is a candidate relay of which a linear average is highest among the candidate relays. ### Claim 7 A user equipment (UE) in a communication system, the UE comprising: at least one processor configured to: receive, from relays, relay discovery messages, each relay discovery message including a user information identifier (ID) associated with a relay among the relays and a service code used for identifying a connectivity service, identify that the connectivity service is discovered in case that the service code included in the relay discovery message is same as a service code configured to the UE for a connectivity service authorized to be accessed by the UE, and the user information ID included in the relay discovery message is same as a user information ID configured to the UE for the relay providing the connectivity service, measure radio qualities between the UE and relays based on a result of the identification, and select one of the relays as a relay for the UE based on the measured radio qualities, wherein each of the radio qualities is a linear average over power contributions of resource elements carrying reference signals. ### Claim 8 (depends on 7) The UE of claim 7, wherein the at least one processor is configured to: identify candidate relays of which linear averages over power contributions of resource elements carrying the reference signals exceed a threshold by a set value among the relays, and select the relay for the UE among the identified candidate relays based on the measured radio qualities. ### Claim 9 (depends on 8) The UE of claim 8, wherein the selected relay is a candidate relay of which a linear average is the highest among the candidate relays. ### Claim 10 A relay in a communication system, the relay comprising: at least one processor configured to transmit a relay discovery message including a service code used for identifying a connectivity service and a user information identifier (ID) associated with a relay among relays, and wherein the relay discovery message is associated with reference signals, wherein the connectivity service is discovered in a user equipment (UE), in case that the service code included in the relay discovery message is same as a service code configured to the UE for a connectivity service authorized to be accessed by the UE, and the user information ID included in the relay discovery message is same as a user information ID configured to the UE for the relay providing the connectivity service, wherein a radio quality between the UE and the relay is to be measured based on the reference signals, wherein the measured radio quality is to be used in selection of a relay for the UE, and wherein the radio quality is a linear average over power contributions of resource elements carrying the reference signals. ### Claim 11 (depends on 10) The relay of claim 10, wherein relays of which linear averages over power contributions of resource elements carrying the reference signals exceed a threshold by a set value among the relays are identified as candidate relays, and the relay is selected for the UE among the identified candidate relays based on the measured radio qualities. ### Claim 12 (depends on 11) The relay of claim 11, wherein the selected relay is a candidate relay of which a linear average is highest among the candidate relays.