# US 2014/0155114 A1 · Method of Handling Device to Device Communication and Related Communication Device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0155114 A1 - Document ID: US20140155114A1 - Status: Published application - Kind: A1 - Application number: 14/098,500 - Filed: 2013-12-05 - Published: 2014-06-05 - Earliest claimed: 2012-12-05 - Assignees: HTC Corporation - Applicants: HTC Corporation - Inventors: Chih-Hsiang Wu - Web page: https://patentgrep.com/patent/US20140155114A1 ## CPC - H04W 76/23: Manipulation of direct-mode connections - H04W 36/033: {in pre-organised networks} - H04W 4/80: Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication - H04W 36/0079: {in case of hand-off failure or rejection} - H04W 76/14: Direct-mode setup - H04W 76/19: Connection re-establishment - H04W 76/34: Selective release of ongoing connections - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract A method of handling device to device communication for a first user equipment (UE) in a wireless communication system includes establishing a Radio Resource Control (RRC) connection to a network of the wireless communication system; performing a proximity-based services (ProSe) communication with a second UE of the wireless communication system; and transmitting a first message to the network when the first UE detects a radio link failure in the ProSe communication; wherein the first message indicates the radio link failure to the network or requests changing to a UE-to-network communication mode from a ProSe communication mode. ## Claims ### Claim 1 A method of handling device to device communication for a first user equipment (UE) in a wireless communication system, the method comprising: establishing a Radio Resource Control (RRC) connection to a network of the wireless communication system; performing a proximity-based services (ProSe) communication with a second UE of the wireless communication system; and transmitting a first message to the network when the first UE detects a radio link failure in the ProSe communication; wherein the first message indicates the radio link failure to the network or requests changing to a UE-to-network communication mode from a ProSe communication mode. ### Claim 2 (depends on 1) The method of claim 1, further comprising: receiving a second message from the network, wherein the second message configures the first UE to stop the ProSe communication. ### Claim 3 (depends on 1) The method of claim 1, further comprising: receiving a second message from the network, wherein the second message indicates the first UE to de-configure the ProSe communication, release the ProSe communication, or release the RRC connection. ### Claim 4 (depends on 1) The method of claim 1, wherein the first message is an RRC message containing a cause value indicating the radio link failure in the ProSe communication. ### Claim 5 (depends on 1) The method of claim 1, wherein the radio link failure in the ProSe communication is detected when the first UE is moving out of a transmission coverage of the second UE for a specific period, or the first UE does not receive data, control signal, or a specific Medium Access Control Protocol Data Unit, an acknowledgement, a feedback of the ProSe communication transmitted from the second UE for a specific period. ### Claim 6 (depends on 5) The method of claim 5, wherein the control signal is a synchronization signal of the ProSe communication, a Demodulation Reference Signal, or a UE specific reference signal designed for the ProSe communication. ### Claim 7 (depends on 6) The method of claim 6, wherein the synchronization signal of the ProSe communication is different from the Primary synchronization signal (PSS) and the Secondary synchronization signal (SSS), or wherein a content of the synchronization signal of the ProSe communication is the same as the PSS or the SSS, but the synchronization signal of the ProSe communication is put in a subframe or an Orthogonal Frequency Division Multiple Access symbol which is in different position than the PSS and the SSS used in the UE-to-network communication mode. ### Claim 8 A method of handling device to device communication for a first user equipment (UE) in a wireless communication system, the method comprising: establishing a Radio Resource Control (RRC) connection to a network of the wireless communication system; performing a proximity-based services (ProSe) communication with a second UE of the wireless communication system; and changing to a UE-to-network communication mode from a ProSe communication mode when the first UE detects a radio link failure in the ProSe communication. ### Claim 9 (depends on 8) The method of claim 8, further comprising: transmitting a message indicating a mode change to the network when changing to the UE-to-network communication mode from the ProSe communication mode. ### Claim 10 (depends on 8) The method of claim 8, wherein the step of changing to the UE-to-network communication mode from the ProSe communication mode when the first UE detects the radio link failure in the ProSe communication comprises at least one of: stopping the ProSe communication; releasing the ProSe communication or releasing the RRC connection of the first UE; and transmitting/receiving data or control signaling only to/from the network. ### Claim 11 (depends on 8) The method of claim 8, wherein the radio link failure in the ProSe communication is detected when the first UE is moving out of a transmission coverage of the second UE for a specific period, or the first UE does not receive data, control signal, or a specific Medium Access Control Protocol Data Unit, an acknowledgement, a feedback of the ProSe communication transmitted from the second UE for a specific period. ### Claim 12 (depends on 11) The method of claim 11, wherein the control signal is a synchronization signal of the ProSe communication, a Demodulation Reference Signal, or a UE specific reference signal designed for the ProSe communication. ### Claim 13 (depends on 12) The method of claim 12, wherein the synchronization signal of the ProSe communication is different from the Primary synchronization signal (PSS) and the Secondary synchronization signal (SSS), or wherein a content of the synchronization signal of the ProSe communication is the same as the PSS or the SSS, but the synchronization signal of the ProSe communication is put in a subframe or an Orthogonal Frequency Division Multiple Access symbol which is in different position than the PSS and the SSS used in the UE-to-network communication mode. ### Claim 14 A method of handling device to device communication for a first user equipment (UE) in a wireless communication system, the method comprising: establishing a Radio Resource Control (RRC) connection to a first network of the wireless communication system; performing a proximity-based services (ProSe) communication with a second UE of the wireless communication system; initiating an RRC connection reestablishment procedure when a connection failure occurs in the RRC connection; and stopping or releasing the ProSe communication when the connection failure occurs in the RRC connection. ### Claim 15 (depends on 14) The method of claim 14, further comprising: sending, to the second UE, a first signal indicating the second UE to stop the ProSe communication or informing the connection failure or loss of the RRC connection. ### Claim 16 (depends on 15) The method of claim 15, further comprising: sending, to the first network or a second network, a second signal indicating that the ProSe communication is stopped or released, or informing the connection failure or loss of the RRC connection. ### Claim 17 A method of handling device to device communication for a first user equipment (UE) in a wireless communication system, the method comprising: establishing a Radio Resource Control (RRC) connection to a network of the wireless communication system; performing a proximity-based services (ProSe) communication with a second UE of the wireless communication system; and suspending the ProSe communication when a connection failure occurs in the RRC connection with the network. ### Claim 18 (depends on 17) The method of claim 17, further comprising: resuming the ProSe communication when the first UE performs the RRC connection reestablishment procedure successfully or when the first UE receives a first RRC connection reconfiguration message from the network after successful completion of the RRC connection reestablishment procedure. ### Claim 19 (depends on 17) The method of claim 17, further comprising: keeping a configuration of the ProSe communication when a radio link failure, a handover failure, a mobility from Evolved Universal Terrestrial Radio Access (E-UTRA) failure, an integrity check failure indication from lower layers, or an RRC connection reconfiguration failure with the network occurs. ### Claim 20 (depends on 17) The method of claim 17, further comprising: sending, to the second UE, a first signal indicating the second UE to suspend the ProSe communication. ### Claim 21 (depends on 20) The method of claim 20, further comprising: sending, to the second UE, a second signal indicating the second UE to resume the ProSe communication after the first UE resumes the ProSe communication.