Random Access Method Maintaining Uplink Data Size Consistency
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Solution Overview
Problem
In communication technologies, terminal devices often experience random access failures during 2-step or 4-step RACH procedures due to changes in uplink grant or PUSCH sizes, leading to unnecessary re-initiation of access procedures and inefficiencies.
Innovation Solution
A method where a terminal device initiates a second random access with the same uplink data size as the first failed access, using configuration information to select appropriate PRACH preamble sets and PUSCH resources, ensuring consistent data sizes across access attempts to prevent new encapsulation processes and improve success rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the terminal device re-initiates a new random access procedure after failure, then the access attempt is renewed, but the MAC PDU encapsulation process must be repeated leading to access failure
Solution Approach 1:
The terminal device performs MAC PDU encapsulation in advance during the first random access procedure, storing the encapsulated MAC PDU in a buffer. When re-initiating random access after failure, the device reuses the pre-prepared MAC PDU without performing encapsulation again, thereby avoiding the technical contradiction between improving access reliability and reducing device complexity.
2Adaptability or versatility
If the uplink grant or PUSCH size changes in the new random access, then the resource allocation is adapted, but the terminal device must perform new MAC PDU encapsulation causing access failure
Solution Approach 1:
The patent applies parameter changes by maintaining consistent uplink grant and PUSCH size parameters between the first and second random access procedures. The terminal device selects resources in the second procedure that match the original parameters, allowing reuse of the pre-prepared MAC PDU and avoiding the need for re-encapsulation, thus resolving the contradiction between adaptability and reliability.
3Manufacturing precision
If the terminal device performs MAC PDU encapsulation according to CCCH/UL data size, then the data is properly formatted, but re-encapsulation is required when uplink grant changes leading to failure
Solution Approach 1:
The terminal device performs the MAC PDU encapsulation process in advance during the initial random access procedure, storing the result in a buffer. This preliminary action eliminates the need for time-consuming re-encapsulation when re-initiating random access, resolving the contradiction between encapsulation accuracy and time loss.
4Productivity
If the terminal device re-initiates random access after failure, then the access procedure is restarted, but the repeated encapsulation process increases failure probability
Solution Approach 1:
The terminal device prepares the MAC PDU in advance during the first access attempt and stores it for reuse. When re-initiating random access to maintain high productivity, the device reuses the pre-prepared MAC PDU, ensuring that the repeated access attempts do not suffer from encapsulation errors, thus resolving the contradiction between productivity and reliability.
Data Source
AI summary
Embodiments of this disclosure provide a random access method and a device, and relate to the field of communications technologies, to resolve the problem of random access failure existing in the related art. The method includes: initiating second random access after first random access fails, where first uplink data in the first random access and second uplink data in the second random access are the same in data size, the first uplink data is uplink data corresponding to a first resource for the first random access, the second uplink data is uplink data corresponding to a second resource for the first random access, the first random access includes two-step random access or four-step random access, and the second random access includes two-step random access or four- step random access.