Random Access Preamble Selection for Message 3 Repetition
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Solution Overview
Problem
Conventional cellular communication systems face inefficiencies in frequency utilization due to the base station's inability to recognize whether a terminal apparatus supports repeated transmission of message 3 in the random access procedure, leading to wasted resources when non-supporting terminals are instructed to repeat transmissions.
Innovation Solution
The system distinguishes between first and second resources for transmitting the random access preamble based on the terminal's capability, allowing the base station to determine if repeated transmission of message 3 is necessary, thereby optimizing resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the base station apparatus instructs repeated transmission of message 3 to all terminal apparatuses, then coverage expansion is achieved, but frequency utilization efficiency deteriorates due to wasted resources when non-supporting terminals are instructed to repeat transmissions
Solution Approach 1:
The patent segments the random access resources into two distinct types: first random access resources for terminals not capable of repeated transmission, and second random access resources for terminals capable of repeated transmission. This segmentation allows the base station to identify terminal capabilities based on which resource type the terminal uses, enabling selective instruction of repeated transmission only to capable terminals, thus avoiding waste of frequency resources while still achieving coverage expansion for supporting terminals
Solution Approach 2:
The patent implements preliminary action by having terminal apparatuses pre-select and use appropriate random access resources based on their capability information before the random access procedure begins. Terminals that support repeated transmission use second random access resources, while those that don't support it use first random access resources. This preliminary selection enables the base station to determine terminal capabilities at the resource detection stage, allowing it to make informed decisions about whether to instruct repeated transmission, thereby preventing resource waste
2Device complexity
If the base station apparatus cannot recognize terminal capability at message 1 reception stage, then the random access procedure remains simple, but resource allocation efficiency deteriorates due to inability to instruct repeated transmission selectively
Solution Approach 1:
The patent introduces an intermediary mechanism - the random access resources themselves serve as indicators of terminal capability. By designing two distinct sets of random access resources (first and second resources) with different characteristics, the system uses the resource selection as an intermediary signal that reveals terminal capability information without requiring complex capability exchange procedures. The base station detects which resource type the terminal used and thereby infers capability, maintaining procedural simplicity while enabling efficient resource allocation
Solution Approach 2:
The patent applies parameter changes by varying characteristics of the random access resources (such as time slot allocation, frequency resources, or preamble formats) to create distinguishable first and second random access resources. These parameter differences serve as implicit capability indicators - terminals select resources based on their capability, and the base station identifies capability by detecting which parameter set the terminal chose, thereby enabling efficient selective repeated transmission instruction without increasing procedural complexity
Data Source
AI summary
A terminal apparatus specifies, based on capability information of the terminal apparatus, one of a first resource with which an apparatus that is not capable of performing repeated transmission of a message 3 in a four-step random access procedure in consecutive slots can transmit a random access preamble, and a second resource that is different from the first resource and with which an apparatus that is capable of performing repeated transmission of the message 3 in consecutive slots can transmit the random access preamble, as a resource to be used when the terminal apparatus transmits the random access preamble, and transmits the random access preamble to a base station apparatus with the specified resource.