# US 12,120,572 B2 · Activation of a secondary cell group using a user equipment configured for dual connectivity with multiple radio access technologies > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,120,572 B2 - Document ID: US12120572B2 - Status: Granted - Kind: B2 - Application number: 17/328,222 - Filed: 2021-05-24 - Published: 2022-01-06 - Granted: 2024-10-15 - Earliest claimed: 2020-07-01 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Ozcan Ozturk; Punyaslok Purkayastha; Ravi Agarwal; Gavin Bernard Horn - Web page: https://patentgrep.com/patent/US12120572B2 ## CPC - H04W 36/305: {Handover due to radio link failure (control signalling for hand-off failure H04W36/0079)} - H04W 76/15: Setup of multiple wireless link connections - H04W 36/0061: {of neighbour cell information} - H04W 36/0077: {of access information of target access point} - H04W 36/00835: {Determination of neighbour cell lists} - H04W 36/0085: {Hand-off measurements} - H04W 74/0833: Random access procedures, e.g. with 4-step access - H04W 76/19: Connection re-establishment - H04W 74/0836: with 2-step access - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may detect radio link failure on a master cell group. Accordingly, the UE may determine a state of a secondary cell group (SCG). Additionally, the UE may initiate activation of the SCG based at least in part on the state of the SCG. For example, the activation of the SCG may be initiated based at least in part on the state being a deactivated state, a dormant state, or an enhanced dormant state. Accordingly, the UE may transmit master cell group (MCG) failure recovery information over the SCG and receive, on the SCG, MCG reconnection information. Numerous other aspects are provided. ## Claims ### Claim 1 A user equipment (UE) for wireless communication, comprising: one or more memories; and one or more processors coupled with the one or more memories, the one or more processors configured to: detect radio link failure (RLF) on a master cell group (MCG); determine a state of a secondary cell group (SCG) based at least in part on the RLF on the MCG, wherein the state of the SCG is a deactivated state, a dormant state, or an enhanced-dormant state; initiate activation of the SCG based at least in part on the state of the SCG, wherein the activation of the SCG comprises transmitting MCG failure recovery information in a random access procedure on the SCG without performing a radio resource control procedure and without transmitting a request for radio resource control re-establishment on the MCG based at least in part on detecting the RLF; receive, on the SCG and based at least in part on transmitting the MCG failure recovery information, MCG reconnection information; and wherein the one or more processors are further configured to: receive or transmit, over the SCG and before failure recovery for the MCG is complete, a data transmission. ### Claim 2 (depends on 1) The UE of claim 1, wherein the UE is configured for multi-radio access technology dual connectivity. ### Claim 3 (depends on 1) The UE of claim 1, wherein initiating activation of the SCG comprises initiating the random access procedure on a primary secondary cell (PSCell) of the SCG. ### Claim 4 (depends on 3) The UE of claim 3, wherein initiating the random access procedure comprises transmitting a random access preamble on the PSCell. ### Claim 5 (depends on 1) The UE of claim 1, wherein the one or more processors are further configured to: receive timing advance (TA) information over the SCG based at least in part on initiating activation of the SCG. ### Claim 6 (depends on 1) The UE of claim 1, wherein the one or more processors are further configured to: transmit the MCG failure recovery information over the SCG, which is forwarded to a master node of the MCG. ### Claim 7 (depends on 1) The UE of claim 1, wherein the state of the SCG is the enhanced-dormant state, further comprising: operating according to the enhanced-dormant state of the SCG. ### Claim 8 (depends on 7) The UE of claim 7, wherein operating according to the enhanced-dormant state of the SCG comprises one or more of: refraining from monitoring a physical downlink control channel on a primary secondary cell (PSCell) of the SCG; performing channel state information (CSI) measurements in an enhanced dormant downlink bandwidth part (BWP) on the PSCell; transmitting CSI reports in a physical uplink control channel for the PSCell; maintaining uplink timing alignment with a secondary node in the PSCell; performing radio resource management measurements on the PSCell; or refraining from performing radio link monitoring measurements. ### Claim 9 (depends on 1) The UE of claim 1, wherein the state of the SCG is the deactivated state, further comprising: operating according to the deactivated state of the SCG. ### Claim 10 (depends on 9) The UE of claim 9, wherein operating according to the deactivated state of the SCG comprises one or more of: refraining from monitoring a physical downlink control channel on a primary secondary cell (PSCell) of the SCG; refraining from performing channel state information (CSI) measurements on the PSCell; refraining from transmitting uplink communications on the PSCell; refraining from maintaining uplink timing alignment with a secondary node in the PSCell; performing radio resource management measurements on the PSCell; or refraining from performing radio link monitoring measurements. ### Claim 11 (depends on 1) The UE of claim 1, wherein the state of the SCG is the dormant state, further comprising: operating according to the dormant state of the SCG. ### Claim 12 A method of wireless communication performed by a user equipment (UE), comprising: detecting radio link failure (RLF) on a master cell group (MCG); determining a state of a secondary cell group (SCG) based at least in part on the RLF on the MCG, wherein the state of the SCG is a deactivated state, a dormant state, or an enhanced-dormant state; initiating activation of the SCG based at least in part on the state of the SCG, wherein the activation of the SCG comprises transmitting MCG failure recovery information in a random access procedure on the SCG without performing a radio resource control procedure and without transmitting a request for radio resource control re-establishment on the MCG based at least in part on detecting the RLF; receiving, on the SCG and based at least in part on transmitting the MCG failure recovery information, MCG reconnection information; and receiving or transmitting, over the SCG and before failure recovery for the MCG is complete, a data transmission. ### Claim 13 (depends on 12) The method of claim 12, wherein initiating activation of the SCG comprises initiating the random access procedure on a primary secondary cell (PSCell) of the SCG. ### Claim 14 (depends on 13) The method of claim 13, wherein initiating the random access procedure comprises transmitting a random access preamble on the PSCell. ### Claim 15 (depends on 12) The method of claim 12, further comprising: receiving timing advance (TA) information over the SCG based at least in part on initiating activation of the SCG. ### Claim 16 (depends on 12) The method of claim 12, wherein the UE is configured for multi-radio access technology dual connectivity. ### Claim 17 (depends on 12) The method of claim 12, further comprising: transmitting the MCG failure recovery information over the SCG, which is forwarded to a master node of the MCG. ### Claim 18 (depends on 12) The method of claim 12, wherein the state of the SCG is the enhanced-dormant state, further comprising: operating according to the enhanced-dormant state of the SCG. ### Claim 19 (depends on 12) The method of claim 12, wherein the state of the SCG is the deactivated state, further comprising: operating according to the deactivated state of the SCG. ### Claim 20 (depends on 12) The method of claim 12, wherein the state of the SCG is the dormant state, further comprising: operating according to the dormant state of the SCG. ### Claim 21 A non-transitory computer-readable medium storing a set of instructions for wireless communication, the set of instructions comprising: one or more instructions that, when executed by one or more processors of a user equipment (UE), cause the UE to: detect radio link failure (RLF) on a master cell group (MCG); determine a state of a secondary cell group (SCG) based at least in part on the RLF on the MCG, wherein the state of the SCG is a deactivated state, a dormant state, or an enhanced-dormant state; initiate activation of the SCG based at least in part on the state of the SCG, wherein the activation of the SCG comprises transmitting MCG failure recovery information in a random access procedure on the SCG without performing a radio resource control procedure and without transmitting a request for radio resource control re-establishment on the MCG based at least in part on detecting the RLF; receive, on the SCG and based at least in part on transmitting the MCG failure recovery information, MCG reconnection information; and receiving or transmitting, over the SCG and before failure recovery for the MCG is complete, a data transmission. ### Claim 22 (depends on 21) The non-transitory computer-readable medium of claim 21, wherein the UE is configured for multi-radio access technology dual connectivity. ### Claim 23 (depends on 21) The non-transitory computer-readable medium of claim 21, wherein initiating activation of the SCG comprises initiating the random access procedure on a primary secondary cell (PSCell) of the SCG. ### Claim 24 (depends on 23) The non-transitory computer-readable medium of claim 23, wherein initiating the random access procedure comprises transmitting a random access preamble on the PSCell. ### Claim 25 (depends on 21) The non-transitory computer-readable medium of claim 21, wherein the one or more instructions cause the UE to: receive timing advance (TA) information over the SCG based at least in part on initiating activation of the SCG. ### Claim 26 (depends on 21) The non-transitory computer-readable medium of claim 21, wherein the one or more instructions cause the UE to: transmit MCG failure recovery information over the SCG, which is forwarded to a master node of the MCG. ### Claim 27 An apparatus for wireless communication, comprising: means for detecting radio link failure (RLF) on a master cell group (MCG); means for determining a state of a secondary cell group (SCG) based at least in part on the RLF on the MCG, wherein the state of the SCG is a deactivated state, a dormant state, or an enhanced-dormant state; means for initiating activation of the SCG based at least in part on the state of the SCG, wherein the activation of the SCG comprises transmitting MCG failure recovery information in a random access procedure on the SCG without performing a radio resource control procedure and without transmitting a request for radio resource control re-establishment on the MCG based at least in part on detecting the RLF; means for receiving, on the SCG and based at least in part on transmitting the MCG failure recovery information, MCG reconnection information; and means for receiving or transmitting, over the SCG and before failure recovery for the MCG is complete, a data transmission.