# US 12,192,779 B2 · Fast primary cell switching in carrier aggregation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,192,779 B2 - Document ID: US12192779B2 - Status: Granted - Kind: B2 - Application number: 17/539,046 - Filed: 2021-11-30 - Published: 2023-06-01 - Granted: 2025-01-07 - Earliest claimed: 2021-11-30 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Yongjun Kwak; Hung Dinh Ly; Ahmed Attia Abotabl - Web page: https://patentgrep.com/patent/US12192779B2 ## CPC - H04W 16/14: Spectrum sharing arrangements {between different networks} - H04W 76/15: Setup of multiple wireless link connections - H04L 1/1893: {Physical mapping arrangements (physical resource mapping in general H04L5/00)} - H04W 16/24: Cell structures - H04W 36/0069: {in case of dual connectivity, e.g. decoupled uplink/downlink} - H04L 1/1671: {the supervisory signal being transmitted together with control information} - 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) ## Abstract Methods, systems, and devices for wireless communications are described. The method includes establishing a first component carrier as a primary cell for the user equipment (UE) and a second component carrier as a secondary cell for the UE, receiving primary cell configuration information for the second component carrier while the second component carrier is the secondary cell for the UE, receiving a control message triggering a switch of the primary cell from the first component carrier to the second component carrier, and establishing the second component carrier as the primary cell for the UE based on the control message and in accordance with the primary cell configuration information associated with the second component carrier. ## Claims ### Claim 1 A user equipment (UE), comprising: one or more memories; and one or more processors coupled to the one or more memories and configured to: establish a first component carrier as a primary cell for the UE and a second component carrier as a secondary cell for the UE, wherein the first component carrier and the second component carrier are in a same timing advance group; receive primary cell configuration information for the second component carrier while the second component carrier is the secondary cell for the UE; receive a control message triggering a switch of the primary cell from the first component carrier to the second component carrier; establish the second component carrier as the primary cell for the UE based at least in part on the control message and in accordance with the primary cell configuration information associated with the second component carrier; and transmit, based at least in part on establishing the second component carrier as the primary cell, a completion message included in a dedicated field of one or more uplink messages. ### Claim 2 (depends on 1) The UE of claim 1, wherein the one or more processors are further configured to: receive the primary cell configuration information after receiving a previous primary cell configuration information for a set of one or more secondary cells associated with the second component carrier and in connection with the secondary cell being added to the set of one or more secondary cells prior to receiving the control message. ### Claim 3 (depends on 1) The UE of claim 1, wherein the one or more processors are further configured to: receive an update to the primary cell configuration information prior to receiving the control message; and incorporate the update into the primary cell configuration information prior to establishing the second component carrier as the primary cell for the UE. ### Claim 4 (depends on 1) The UE of claim 1, wherein the one or more processors are further configured to: use at least a portion of a configuration associated with the first component carrier as the primary cell with the second component carrier established as the primary cell. ### Claim 5 (depends on 1) The UE of claim 1, wherein the one or more processors are further configured to: determine, before receiving the control message, that the primary cell configuration information does not include at least a portion of a configuration for configuring the second component carrier as the primary cell; and use at least a portion of a configuration associated with the first component carrier as the primary cell to generate or modify the configuration for the second component carrier as the primary cell. ### Claim 6 (depends on 1) The UE of claim 1, wherein the primary cell configuration information comprises a first primary cell configuration of a first secondary cell of the second component carrier and a second primary cell configuration of a second secondary cell of the second component carrier. ### Claim 7 (depends on 1) The UE of claim 1, wherein the primary cell configuration information comprises a physical uplink control channel configuration for primary cells, a random access channel configuration for primary cells, a measurement configuration for primary cells, a radio link failure configuration for primary cells, or a radio link monitoring configuration for primary cells, or a combination thereof. ### Claim 8 (depends on 1) The UE of claim 1, wherein the control message specifies the primary cell configuration information to be used with the second component carrier when the second component carrier is established as the primary cell. ### Claim 9 (depends on 1) The UE of claim 1, wherein the control message comprises a downlink control information message, the downlink control information message comprising a field dedicated to indicating one or more of: that the second component carrier is selected to be established as the primary cell, that the first component carrier is selected to be established as the secondary cell, or whether the first component carrier is selected for deactivation, or any combination thereof. ### Claim 10 (depends on 1) The UE of claim 1, wherein the control message indicates whether the first component carrier is selected for deactivation. ### Claim 11 (depends on 1) The UE of claim 1, wherein the control message comprises a media access control message, a header of the media access control message indicating one or more of: that the second component carrier is selected to be established as the primary cell, that the first component carrier is selected to be established as the secondary cell, or whether the first component carrier is selected for deactivation, or any combination thereof. ### Claim 12 (depends on 1) The UE of claim 1, wherein the control message comprises a radio resource control message indicating one or more of: that the second component carrier is selected to be established as the primary cell, that the first component carrier is selected to be established as the secondary cell, or whether the first component carrier is selected for deactivation, or any combination thereof. ### Claim 13 (depends on 1) The UE of claim 1, wherein, to transmit the completion message, the one or more processors are further configured to: transmit the completion message via the second component carrier as the primary cell or the first component carrier as the secondary cell. ### Claim 14 (depends on 13) The UE of claim 13, the dedicated field is included in uplink control information via a physical uplink control channel or a physical uplink shared channel. ### Claim 15 (depends on 13) The UE of claim 13, wherein the completion message is transmitted via a hybrid automatic repeat request acknowledgment. ### Claim 16 (depends on 1) The UE of claim 1, wherein establishing the second component carrier as the primary cell is based at least in part on the first component carrier and the second component carrier being in the same timing advance group. ### Claim 17 (depends on 1) The UE of claim 1, wherein establishing the second component carrier as the primary cell is based at least in part on the first component carrier and the second component carrier being associated with a same network device. ### Claim 18 (depends on 1) The UE of claim 1, wherein the one or more processors are further configured to: receive a second control message triggering a switch of the primary cell from the second component carrier back to the first component carrier; and reestablish the first component carrier as the primary cell for the UE and the second component carrier as the secondary cell for the UE based at least in part on the second control message. ### Claim 19 (depends on 18) The UE of claim 18, wherein: the control message is received based at least in part on a first network condition or the second control message is received based at least in part on a second network condition, or both; and the first network condition or the second network condition is, or both are, based at least in part on a network load associated with the first component carrier or a network load associated with the second component carrier, or a network load associated with the first component carrier and the second component carrier. ### Claim 20 A network device, comprising: one or more memories; and one or more processors coupled to the one or more memories and configured to: establish a first component carrier as a primary cell for a user equipment (UE) and a second component carrier as a secondary cell for the UE, wherein the first component carrier and the second component carrier are in a same timing advance group; transmit, to the UE, primary cell configuration information for the second component carrier while the second component carrier is the secondary cell for the UE; transmit, to the UE, a control message triggering a switch of the primary cell from the first component carrier to the second component carrier; establish the second component carrier as the primary cell for the UE based at least in part on the control message and in accordance with the primary cell configuration information associated with the second component carrier; and receive, based at least in part on establishing the second component carrier as the primary cell, a completion message included in a dedicated field of one or more uplink messages. ### Claim 21 (depends on 20) The network device of claim 20, wherein the one or more processors are further configured to: transmit the primary cell configuration information after transmitting a previous primary cell configuration information for a set of one or more secondary cells associated with the second component carrier and in connection with the secondary cell being added to the set of one or more secondary cells prior to receiving the control message. ### Claim 22 (depends on 20) The network device of claim 20, wherein the one or more processors are further configured to: transmit an update to the primary cell configuration information prior to receiving the control message. ### Claim 23 (depends on 20) The network device of claim 20, wherein the primary cell configuration information comprises a first primary cell configuration of a first secondary cell of the second component carrier and a second primary cell configuration of a second secondary cell of the second component carrier. ### Claim 24 (depends on 20) The network device of claim 20, wherein the primary cell configuration information comprises a physical uplink control channel configuration for primary cells, a random access channel configuration for primary cells, a measurement configuration for primary cells, a radio link failure configuration for primary cells, or a radio link monitoring configuration for primary cells, or a combination thereof. ### Claim 25 (depends on 20) The network device of claim 20, wherein the control message specifies the primary cell configuration information to be used with the second component carrier when the second component carrier is established as the primary cell. ### Claim 26 (depends on 20) The network device of claim 20, wherein the control message comprises a downlink control information message, the downlink control information message comprising a field dedicated to indicating one or more of: that the second component carrier is selected to be established as the primary cell, that the first component carrier is selected to be established as the secondary cell, or whether the first component carrier is selected for deactivation, or any combination thereof. ### Claim 27 (depends on 20) The network device of claim 20, wherein the control message includes an indicator indicating whether the first component carrier is selected for deactivation. ### Claim 28 (depends on 20) The network device of claim 20, wherein the control message comprises a media access control message, a header of the media access control message indicating one or more of: that the second component carrier is selected to be established as the primary cell, that the first component carrier is selected to be established as the secondary cell, or whether the first component carrier is selected for deactivation, or any combination thereof. ### Claim 29 A method of fast primary cell switching for wireless communication at a user equipment (UE), comprising: establishing a first component carrier as a primary cell for the UE and a second component carrier as a secondary cell for the UE, wherein the first component carrier and the second component carrier are in a same timing advance group; receiving primary cell configuration information for the second component carrier while the second component carrier is the secondary cell for the UE; receiving a control message triggering a switch of the primary cell from the first component carrier to the second component carrier; establishing the second component carrier as the primary cell for the UE based at least in part on the control message and in accordance with the primary cell configuration information associated with the second component carrier; and transmitting, based at least in part on establishing the second component carrier as the primary cell, a completion message included in a dedicated field of one or more uplink messages. ### Claim 30 A method of fast primary cell switching for wireless communication at a network device, further comprising: establishing a first component carrier as a primary cell for a user equipment (UE) and a second component carrier as a secondary cell for the UE, wherein the first component carrier and the second component carrier are in a same timing advance group; transmitting, to the UE, primary cell configuration information for the second component carrier while the second component carrier is the secondary cell for the UE; transmitting, to the UE, a control message triggering a switch of the primary cell from the first component carrier to the second component carrier; establishing the second component carrier as the primary cell for the UE based at least in part on the control message and in accordance with the primary cell configuration information associated with the second component carrier; and receiving, based at least in part on establishing the second component carrier as the primary cell, a completion message included in a dedicated field of one or more uplink messages.