Two-Step Random Access RAR Identification via RAPID Segmentation
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Solution Overview
Problem
In the context of New Radio (NR) systems, the existing random access procedures, particularly the two-step method, face challenges in efficiently managing random access response messages for multiple preambles, leading to delays and inefficiencies, especially in ultra-reliable and low-latency scenarios.
Innovation Solution
A method where a terminal device determines an uplink resource for sending a response message based on indication information included in Message B, confirming the completion of the two-step random access procedure by sending the response message, utilizing physical downlink shared channels and control channels to schedule and transmit the necessary information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single PDSCH carries multiple RAR messages for different preambles, then resource utilization improves, but determining the correct RAR becomes more complex
Solution Approach 1:
The patent applies local quality by making each RAR message have a unique identifier (RAPID) that locally distinguishes it from other RAR messages in the same PDSCH. This allows the terminal to quickly identify and select the relevant RAR without complex global analysis, resolving the contradiction between efficient resource utilization and simple identification.
2Productivity
If the network sends RAR messages for multiple preambles in one PDSCH, then transmission efficiency improves, but the terminal device's processing burden increases
Solution Approach 1:
The patent segments the RAR response by assigning each RAR a unique RAPID that corresponds to a specific preamble. This segmentation allows the terminal to efficiently process multiple RARs by simply matching RAPIDs without having to analyze the entire PDSCH content comprehensively, thus reducing processing burden while maintaining transmission efficiency.
Solution Approach 2:
The RAPID acts as an intermediary between the PDSCH carrying multiple RARs and the terminal device. It provides a simple matching mechanism that bridges the gap between efficient bulk transmission and simple terminal processing, allowing the terminal to quickly identify its relevant RAR without complex processing.
3Reliability
If indication information is added to help terminals identify RARs, then access reliability improves, but message overhead increases
Solution Approach 1:
The RAPID field serves multiple functions: it identifies the preamble, links the RAR to the correct terminal, and enables efficient filtering. This multi-functionality provides reliable access identification without requiring separate indication information for each function, thus improving reliability while minimizing message overhead.
Data Source
AI summary
Provided in the embodiments of the present disclosure are a random access method, a terminal device and a network device. The method includes sending, by the terminal device, a first message in a random access procedure to the network device. The first message includes a first random access preamble and a first physical uplink shared channel (PUSCH). The method further includes monitoring, by the terminal device, whether a first random access response (RAR) is sent by the network device within a first RAR window. The first RAR is an RAR of a first type, the first RAR includes a response to the first message, the first RAR is transmitted on a first physical downlink shared channel (PDSCH), the first PDSCH includes at least one RAR of the first type, and the first PDSCH is scheduled by a first physical downlink control channel (PDCCH).