5G Random Access Channel Access Type Determination
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Solution Overview
Problem
In 5G wireless communication systems, the synchronization status of user equipment (UE) follows the primary timing advance (pTAG), leading to unnecessary delays in communication on secondary timing advance (sTAG) serving cells when the pTAG's time alignment timer expires, as all TAGs are considered expired, causing delays in random access procedures.
Innovation Solution
The method involves receiving a random access response (RAR) with an uplink grant and first information for a channel access procedure type for MSG3 transmission, performing the identified channel access procedure, and then receiving downlink control information (DCI) for retransmission with a different channel access procedure type, allowing for separate timing management of pTAG and sTAGs to prevent timer-related delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the synchronization status of UE follows the pTAG and all TAGs are considered expired when pTAG's time alignment timer expires, then the timing synchronization is maintained across all TAGs, but communication delays occur on sTAG serving cells
Solution Approach 1:
The patent segments the timing advance management by introducing separate time alignment timers for pTAG and sTAG. This allows independent expiration and renewal of timing synchronization for primary and secondary TAGs, preventing the propagation of timing issues from pTAG to sTAG and eliminating unnecessary communication delays on sTAG serving cells.
2Device complexity
If a single time alignment timer is used for all TAGs, then the system complexity is reduced, but the random access procedure efficiency deteriorates due to waiting for pTAG synchronization
Solution Approach 1:
The patent divides the timing management into separate time alignment timers for pTAG and sTAG, allowing parallel and independent operation. This segmentation enables sTAG to proceed with random access procedures without waiting for pTAG synchronization, thereby improving overall system productivity while maintaining manageable complexity through clear separation of concerns.
Data Source
AI summary
The disclosure relates to a communication method and system for converging a 5th-Generation (5G) communication system for supporting higher data rates beyond a 4th-Generation (4G) system with a technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. The disclosure provides method and apparatus for determining channel access procedure type for Msg3 transmission. The method includes transmitting, to a terminal, a random access response (RAR) including an uplink grant for a transmission of a message 3 (MSG3) associated with a random access procedure and first information associated with a type for a first channel access procedure for the transmission of the MSG3; transmitting, to the terminal, downlink control information (DCI) scheduling a retransmission of the MSG3 in case that the MSG3 is not received, the DCI including second information associated with a type for a second channel access procedure for the retransmission of the MSG3; and receiving, from the terminal, the MSG3 based on the second channel access procedure, which is based on the type identified by the second information.