Dual-Mode Random Access Procedure for Low-Latency Wireless Communication
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Solution Overview
Problem
Existing random access procedures in communications technologies, such as the 4-step contention-based random access, suffer from high delay and interaction complexity, making them unsuitable for scenarios with high delay requirements. Additionally, terminal devices struggle to balance delay and power consumption when choosing between the 2-step and 4-step random access procedures.
Innovation Solution
A method and apparatus for a terminal device to simultaneously perform both the 2-step and 4-step random access procedures, monitoring responses in designated windows to determine successful access. This approach allows the terminal device to select the appropriate random access type based on delay and power consumption considerations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the terminal device performs only the 2-step random access procedure, then the delay is reduced, but the reliability decreases when the 2-step procedure fails
Solution Approach 1:
The terminal device dynamically switches between 2-step and 4-step random access procedures based on whether a response is detected. The device first attempts the low-latency 2-step procedure, and only transitions to the 4-step procedure if the 2-step procedure fails, creating a dynamic adaptive access mechanism that optimizes both delay and reliability
Solution Approach 2:
The terminal device performs preliminary monitoring of the response window for the 2-step random access procedure before committing to the 4-step procedure. By checking for the presence of a response message in advance, the device can determine whether to proceed with further 4-step operations or conclude that random access succeeded, avoiding unnecessary delays
2Reliability
If the terminal device performs both 2-step and 4-step random access procedures simultaneously, then the reliability improves, but the power consumption increases
Solution Approach 1:
The terminal device dynamically adjusts its operation mode based on response detection. When a response is detected in the response window, the device immediately stops further monitoring and processing for the 4-step procedure, transitioning from a high-power dual-procedure mode to a low-power state, thus adapting power consumption to actual access success
Solution Approach 2:
The terminal device skips the remaining steps of the 4-step random access procedure as soon as a response is detected in the response window. Instead of completing all 4 steps, the device rushes through by concluding the random access process early, thereby avoiding unnecessary power consumption from redundant monitoring and processing operations
3Adaptability or versatility
If the terminal device monitors both first response and second response, then the adaptability improves, but the device complexity increases
Solution Approach 1:
The response monitoring process is segmented into distinct phases: first monitoring the response window for any response message related to the 2-step procedure, and only if no response is detected, proceeding to monitor for messages related to the 4-step procedure. This segmentation divides the complex monitoring task into manageable, sequential stages with clear decision points
Solution Approach 2:
The monitoring behavior is made dynamic through conditional logic based on response detection. The device adjusts its monitoring strategy in real-time: if a response is detected, monitoring stops and random access is declared successful; if no response is detected after the response window expires, the device transitions to monitoring for 4-step procedure messages, creating a flexible adaptive monitoring mechanism
Data Source
AI summary
This application provides a random access method and apparatus. The method includes: sending, to a network device, a random access signal and first information used for contention resolution; monitoring a first response and a second response, where the first response is a response to the random access signal and includes an uplink grant, and the second response is a response to the first information used for contention resolution; and when detecting the first response, and detecting the second response before a time domain position of the uplink grant, determining that random access succeeds; or when detecting the first response, sending second information used for contention resolution by using the uplink grant, and when detecting the second response or a third response, determining that random access succeeds, where the third response is a response to the second information used for contention resolution.