RACH Process Differentiation via DCI Parameters
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Solution Overview
Problem
The 4-step RACH process in 5G systems is high in latency and overhead, making it unsuitable for low-latency and high-reliability scenarios, and there is a need to determine the type of RACH process and scheduling mechanisms for different types of RACH processes.
Innovation Solution
A method and device for information transmission that involves a terminal device and a network device, where the terminal device sends a preamble and uplink data channel to the network device, receiving downlink control information (DCI) to determine the type of RACH process, content, transmission mechanism, or information carried in the data scheduled by the DCI, allowing for differentiation between 2-step and 4-step RACH processes through related parameters such as RNTI and search space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a 4-step RACH process is used, then compatibility with LTE is maintained, but access latency increases and overhead increases
Solution Approach 1:
The patent segments the RACH process into two distinct types: 2-step RACH and 4-step RACH. The network device and terminal device determine which type to use based on specific conditions (e.g., service requirements, channel conditions). This segmentation allows the system to choose the optimal process for each scenario, reducing access latency when 2-step is appropriate while maintaining LTE compatibility when 4-step is used.
Solution Approach 2:
The patent introduces dynamic selection between 2-step and 4-step RACH processes based on real-time conditions. The network device can dynamically indicate to the terminal device which RACH type to use through downlink control information (DCI), allowing the system to adapt to changing channel conditions and service requirements, thereby optimizing access latency while maintaining backward compatibility.
2Adaptability or versatility
If a 4-step RACH process is used, then LTE compatibility is maintained, but overhead increases
Solution Approach 1:
The patent segments the RACH process into two types with different overhead characteristics. The 2-step RACH process combines message transmission and scheduling in fewer steps, reducing the quantity of control information and signaling overhead compared to the traditional 4-step process. This segmentation allows the system to reduce overhead when using the optimized 2-step procedure while maintaining LTE compatibility through the 4-step option.
Solution Approach 2:
The patent changes key parameters of the RACH process by introducing a 2-step variant that modifies the message exchange structure. By changing the process parameters (number of steps, message combining), the system reduces signaling overhead while maintaining compatibility with existing LTE infrastructure through the 4-step option.
3Productivity
If DCI parameters are used to determine RACH process type, then transmission efficiency improves, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring the terminal device with multiple RACH process types and their corresponding DCI parameter interpretations. The device is prepared in advance to recognize and process different DCI formats that indicate specific RACH types. This preliminary configuration enables efficient runtime determination without requiring complex real-time analysis, thus improving transmission efficiency while managing device complexity.
Solution Approach 2:
The patent uses parameter changes in DCI fields to indicate different RACH process types. By encoding RACH type information in existing DCI parameters (such as RNTI values, search space indicators, or specific bit fields), the system achieves efficient transmission without requiring entirely new signaling structures. This approach improves transmission efficiency while minimizing the increase in device complexity by reusing existing parameter frameworks.
Data Source
AI summary
A method for information transmission includes that: a terminal device sends a first preamble and a first uplink data channel to a network device; the terminal device receives first downlink control information from the network device; and the terminal device determines at least one of the following based on a related parameter of the first DCI: a type of a random access channel (RACH) process; a content of the first DCI; a transmission mechanism for first data scheduled by the first DCI; or information carried in the first data scheduled by the first DCI. A device for information transmission is also provided.