RA-RNTI Differentiation for Two-Step and Four-Step RACH
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Solution Overview
Problem
In wireless communication systems, the existing random access procedures for LTE and 5G NR struggle to differentiate between two-step and four-step RACH processes when terminal apparatuses share the same radio resources, leading to issues in identifying the starting location of the MAC subheader and RA response for terminal apparatuses executing four-step RACH.
Innovation Solution
The solution involves calculating a unique Random Access-Radio Network Temporary Identifier (RA-RNTI) for each type of RACH process, allowing for separate radio resources to be designated via different PDCCHs, thereby preventing interference and ensuring that terminal apparatuses can correctly receive their RA responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the same radio resources are used for both two-step and four-step RACH processes, then resource utilization efficiency is improved, but interference between the two processes occurs causing terminal apparatuses to be unable to correctly identify the starting location of MAC subheader and RA response
Solution Approach 1:
The patent applies local quality by differentiating the RA-RNTI calculation based on the specific type of RACH process (two-step or four-step). Different terminal apparatuses executing different RACH processes are assigned different RA-RNTI values even when using the same radio resources, allowing each terminal to correctly identify and receive its corresponding response without interference.
2Device complexity
If RA-RNTI is calculated using the same formula for both two-step and four-step RACH, then implementation simplicity is maintained, but terminal apparatuses cannot be differentiated leading to reception errors
Solution Approach 1:
The patent changes the parameter used in RA-RNTI calculation by introducing a step type indicator that differs between two-step and four-step RACH processes. This parameter change enables the system to differentiate between terminal apparatuses executing different RACH types while maintaining a relatively simple RA-RNTI calculation structure based on radio resource identifiers.
Data Source
AI summary
A terminal apparatus, which is able to establish a connection with a base station apparatus via a two-step random access procedure by transmitting a first signal including a random access preamble and predetermined information to the base station apparatus and receiving a second signal as a reply to the first signal from the base station apparatus, acquires a random access-radio network temporary identifier (RA-RNTI) on the basis of a radio resource having been used to transmit the predetermined information with the first signal, and executes reception processing of the second signal using the RA-RNTI.