Terminal Random Access Procedure Selection in Communication Systems
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Solution Overview
Problem
Current communication systems face challenges in efficiently managing access procedures, particularly in high-frequency bands, where existing methods lack flexibility in adapting to different operation states of terminals and do not effectively distinguish between various types of random access messages, leading to suboptimal performance.
Innovation Solution
The proposed solution involves a method where terminals receive configuration information for 2-step or 4-step random access procedures, transmitting specific random access messages with indicators for different types of MAC subPDUs, allowing the system to determine the appropriate access procedure based on received indicators, and using distinct radio network temporary identifiers for each procedure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single random access procedure is used for all terminal states, then the system is simple to operate, but it cannot adapt to different terminal operation states leading to suboptimal performance
Solution Approach 1:
The patent implements dynamic selection between 2-step and 4-step random access procedures based on terminal operation states. The terminal determines which procedure to use according to its current state (e.g., whether it has uplink data to transmit), allowing the system to adapt flexibly to different conditions while maintaining clear operational rules for each state.
Solution Approach 2:
The patent segments the random access procedure into two distinct types: 2-step RACH and 4-step RACH. Each type is optimized for specific terminal states, with the 2-step procedure suitable for terminals with uplink data and the 4-step procedure for other cases. This segmentation allows the system to provide optimized access for different scenarios without requiring a single complex procedure to handle all cases.
2Loss of information
If random access messages are transmitted without type indicators, then the message format is simple, but the system cannot effectively distinguish between different types of MAC subPDUs
Solution Approach 1:
The patent uses indicator fields (effectively 'color codes') within the MAC subPDU structure to identify different message types. Specific bit patterns in the MAC subheader indicate whether the subPDU contains uplink grant, timing advance, or other control information. This allows the receiver to quickly identify and process different message types without requiring complex external signaling or lengthy message formats.
Solution Approach 2:
The MAC subPDU structure serves as an intermediary that carries both the control information and type identification within a unified format. The standardized MAC subheader with its indicator fields acts as a mediator between the random access preamble and the subsequent processing, enabling the system to distinguish message types efficiently while maintaining a regular processing flow.
3Productivity
If the same radio network temporary identifier is used for both 2-step and 4-step procedures, then the identifier system is simple, but the system cannot distinguish between procedures and optimize resource allocation
Solution Approach 1:
The patent segments the identifier space by using different Radio Network Temporary Identifiers (RNTIs) for different random access procedures. Specifically, it uses RA-RNTI for 2-step RACH and another RA-RNTI for 4-step RACH. This segmentation allows the system to track and manage resources for each procedure type independently, enabling optimized resource allocation for terminals in different access modes without requiring complex cross-procedure identifier management.
Data Source
AI summary
Provided is a method for controlling the access of a terminal in a communication system. An operation method of a terminal comprises the steps of: receiving, from a base station, configuration information for a two-step random access procedure; transmitting, to the base station, RA MSG-A including an RA preamble and an RA payload, on the basis of the configuration information; and receiving, from the base station, RA MSG-B, which is a response to the RA MSG-A. Therefore, communication system performance can be improved.