Dynamic TTI Configuration for Msg3 Random Access Latency
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Solution Overview
Problem
Current wireless communication systems, particularly in Evolved Universal Terrestrial Radio Access Networks (E-UTRAN), face challenges in optimizing the random access procedure, especially in terms of transmission time interval (TTI) duration and timing offset for Msg3, which affects latency and resource efficiency during the random access process.
Innovation Solution
The method involves transmitting TTI information for Msg3 within Msg2, allowing the User Equipment (UE) to adjust its Msg3 transmission based on provided TTI duration and start timing offset, enabling dynamic TTI adjustment and reducing processing latency by incorporating additional fields in the Random Access Response (RAR) or common fields in Msg2.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If fixed TTI duration is used for Msg3 transmission, then system complexity is reduced, but random access latency cannot be optimized for different service requirements
Solution Approach 1:
The patent applies dynamics by enabling flexible TTI duration selection for Msg3 transmission. The network can dynamically configure different TTI durations (e.g., 2ms or 10ms) based on service requirements, and the UE adapts its Msg3 transmission accordingly. This is achieved through RRC configuration parameters that allow the UE to select appropriate TTI duration and timing offset values, transforming the fixed TTI system into a dynamic one that can optimize latency when needed while maintaining simplicity for standard cases.
2Productivity
If flexible TTI duration and timing offset are configured for Msg3, then random access performance is improved, but signaling overhead increases
Solution Approach 1:
The patent employs parameter changes by introducing configurable TTI duration and timing offset parameters in the RRC configuration. These parameters allow the network to optimize random access performance by adjusting TTI duration (e.g., 2ms or 10ms) and timing offset values based on service requirements. The UE uses these parameters to determine Msg3 transmission timing, enabling flexible optimization of random access procedure efficiency while managing signaling overhead through selective configuration.
3Loss of time
If UE waits for fixed timing offset after Msg2 before transmitting Msg3, then timing synchronization is simplified, but access latency increases
Solution Approach 1:
The patent applies preliminary action by having the UE determine the timing offset for Msg3 transmission in advance, based on RRC configuration parameters received before the random access procedure. The configuration includes timingOffsetForMsg3 values that the UE uses to calculate the appropriate waiting time after receiving Msg2 before transmitting Msg3. This preliminary configuration approach allows the UE to optimize transmission timing without complex real-time timing management, reducing access latency while maintaining manageable timing synchronization.
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AI summary
A method and apparatus are disclosed, from the perspective of the UE, for performing random access procedure. Preferably, the method includes the UE receiving a message from a network. The message includes a TTI information of Msg3 transmission (1205). In addition, the method includes the UE transmitting a Msg1 to the network (1210). The method also includes the UE receiving a Msg2 from the network for responding the Msg1 (1215). The method further includes the UE transmitting a Msg3 to the network according to the TTI information (1220).