Random Access Resource Selection With Physical Layer Time Delay Constraints
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current cellular radio communication systems face challenges in ensuring the success of random access procedures due to the neglect of time delay limitations by the MAC layer during PRACH resource selection, leading to potential collisions with the physical layer's timing requirements.
Innovation Solution
The method involves a terminal that considers the time delay defined by the physical layer when selecting a random access resource, using a specific formula to determine a subframe that meets the required time difference, ensuring the successful transmission of the physical random access preamble by taking into account the PRACH configuration index, mask index, and uplink/downlink configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the MAC layer selects PRACH resources without considering physical layer time delay requirements, then the resource selection flexibility is improved, but the random access success rate deteriorates due to timing collisions
Solution Approach 1:
The patent changes the selection parameters by introducing time delay constraints (k≥6ms) as a new parameter that the MAC layer must consider when selecting PRACH resources. This transforms the resource selection from an unconstrained flexible process to a constrained process that guarantees physical layer timing requirements are met, thereby improving random access success rate while maintaining adequate flexibility through the use of offset values and multiple candidate subframes.
2Reliability
If the terminal waits for the minimum time delay k before selecting PRACH resources, then the physical layer timing requirements are satisfied, but the access delay increases
Solution Approach 1:
The patent applies preliminary action by having the terminal pre-calculate and identify candidate subframes that satisfy the time delay constraint k≥6ms before actually initiating the random access procedure. The terminal proactively determines the earliest valid PRACH opportunity in advance, rather than waiting passively, thus minimizing the actual access delay while ensuring timing requirements are met.
Solution Approach 2:
The patent introduces dynamic selection of offset values within the time delay constraint. The terminal can dynamically choose different offset values (≥6ms) based on current system conditions and available PRACH resources, allowing flexible optimization of access delay while maintaining reliability. This dynamic approach enables the system to adapt to varying conditions rather than using a fixed waiting period.
Data Source
Figure 1~2
Figure 3~5
Figure 6
AI summary
The present invention discloses a method and terminal for selecting a random access resource, the method includes: the terminal receives the physical downlink control channel signaling sent by a system; the terminal determines the first subframe which meets a condition A and contains a random access resource from the subsequent subframes of the subframe receiving the physical downlink control channel signaling, the condition A is that the time difference between the first subframe and the subframe receiving the physical downlink control channel signaling is greater than or equal to k, k is the time delay defined by the physical layer of the terminal; and the terminal starts a selection on the subframe containing a random access source from the first subframe.