Two-Step Random Access Failure Handling in 5G
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Solution Overview
Problem
There is a lack of a suitable solution in 5G systems for determining a handling procedure for failures in contention-based random access, which is critical for ensuring reliable communication.
Innovation Solution
A method and device for contention-based random access that involve sending and receiving specific messages (Msg1 and Msg2) between terminal and network side devices, where the terminal device determines failure conditions and performs handling procedures based on the network's response, including switching between two-step and four-step contention-based random access protocols, and configuring backoff and power ramping parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If two-step contention-based random access is used to reduce access delay, then access speed is improved, but reliability deteriorates due to lack of failure handling procedures
Solution Approach 1:
The patent implements dynamic switching between two-step and four-step random access procedures based on failure detection. The terminal device monitors the reception of Msg2 messages and dynamically transitions from the simplified two-step procedure to the more robust four-step procedure when failures are detected, allowing the system to adapt its complexity based on actual channel conditions and failure rates
Solution Approach 2:
The patent changes the procedural parameters of the random access mechanism by switching between different access modes (two-step vs. four-step). When failure conditions are met (such as not receiving Msg2 within a timer window or receiving a backoff indicator), the system changes the access procedure parameters from the optimized two-step mode to the more reliable four-step mode with intermediate acknowledgment messages
2Reliability
If adaptive switching between two-step and four-step random access is implemented, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent segments the random access procedure into distinct phases and modes (two-step mode and four-step mode) with clear transition conditions. The failure handling is segmented into specific detection mechanisms (timer-based Msg2 reception monitoring, backoff indicator detection) and corresponding response actions (switching to four-step procedure, resetting counters, re-attempting access), making the complexity manageable through structured division of the access process
Solution Approach 2:
The patent implements feedback mechanisms where the terminal device monitors the network's response (Msg2 message reception) and uses this feedback to determine whether to continue with two-step access or switch to four-step access. The feedback loop includes detecting Msg2 reception status, checking for backoff indicators, and adjusting the access strategy accordingly, which automates the complexity management through condition-based decision making
Data Source
AI summary
A method and a device for contention-based random access are provided. The method includes: sending, by a terminal side device, an Msg1 corresponding to a two-step contention-based random access to a network side device; receiving, by the terminal side device, an Msg2 returned by the network side device, wherein if the terminal side device determines a failure of the two-step contention-based random access occurs according to a receiving condition of the Msg2 message, the terminal side device performs a handling procedure for the failure of the two-step contention-based random access. The Msg2 message is determined by the network side device according to a receiving condition that the network side device receives the Msg1 message.