PDCCH Handling During SCG Activation Without Random Access
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently handling the physical downlink control channel when a secondary cell group is activated, particularly in scenarios where a random access channel procedure is not performed.
Innovation Solution
A method that allows a wireless device to reactivate a secondary cell group without performing a random access channel procedure, by determining quasi-co-located information for the secondary cell group implicitly or explicitly, and using radio link monitoring parameters to quickly detect and recover from communication problems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a random access channel procedure is performed during secondary cell group activation, then reliable link establishment is achieved, but activation time and delay increase
Solution Approach 1:
The patent applies preliminary action by pre-configuring QCL information and dedicated RACH resources before SCG activation. The UE receives and stores QCL configuration information during RRC connection setup, so when SCG activation is triggered, the UE can immediately use the pre-configured QCL information for PDCCH reception without waiting for new configuration, thereby reducing activation delay while maintaining reliability
Solution Approach 2:
The patent extracts the QCL information determination step from the traditional RACH procedure. Instead of requiring full RACH procedure execution for QCL acquisition, the UE extracts and uses only the necessary QCL information from pre-configured parameters, eliminating unnecessary RACH steps while ensuring reliable PDCCH reception during SCG activation
2Reliability
If QCL information is determined explicitly through configuration, then PDCCH reception reliability is improved, but signaling overhead increases
Solution Approach 1:
The patent applies local quality by providing QCL information specifically for the PDCCH of the activating SCG rather than generalizing to all downlink channels. The QCL configuration is locally optimized for PDCCH reception requirements, using reference signals that are most appropriate for control channel demodulation, thereby improving PDCCH reliability without unnecessarily configuring QCL for other channels and reducing overall signaling overhead
Solution Approach 2:
The patent uses partial action by providing only the essential QCL information needed for PDCCH reception during SCG activation, rather than providing complete QCL configurations for all possible downlink channels and scenarios. This partial configuration approach achieves the necessary reliability for control channel reception while minimizing signaling overhead
Data Source
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AI summary
This disclosure relates to techniques for physical downlink control channel handling when a secondary cell group is activated in a wireless communication system. A wireless device may establish a wireless link with a master cell group. A secondary cell group may be configured. The wireless device may receive an indication to activate the secondary cell group without performing a random access channel procedure on the secondary cell group. The wireless device may determine quasi-co-located information for a physical downlink control channel of the secondary cell group. The wireless device may perform physical downlink control channel decoding for the physical downlink control channel of the secondary cell group using the determined quasi-co-located information.