Message 3 Repetition for Random Access Coverage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wireless communication systems, particularly in 5G NR, the random access procedure often faces issues with message reception due to high carrier frequencies leading to path loss, where beamforming may not be established, causing delays or preventing user equipment (UE) from connecting to the base station.
Innovation Solution
The proposed solution involves repeating random access message 3 in the RACH procedure based on properties of the random access preamble, such as its format or inclusion in a configured subset of sequences, to enhance coverage and ensure correct reception, which includes determining and applying appropriate repetition parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If random access message 3 is transmitted without repetition, then transmission time is reduced, but message reception reliability deteriorates under high carrier frequencies and path loss conditions
Solution Approach 1:
The patent implements dynamic message repetition where the UE determines whether to repeat message 3 based on detected downlink beam failure conditions. When beam failure is detected, repetition is activated; when not detected, normal single transmission is used. This dynamic adaptation resolves the contradiction by adjusting transmission behavior according to actual channel conditions.
Solution Approach 2:
The patent changes the transmission parameter (repetition count) based on beam failure detection status. The UE monitors downlink beam quality and switches between two transmission modes: single transmission for good conditions and repeated transmission for poor conditions. This parameter change strategy allows the system to maintain reliability when needed while avoiding unnecessary time loss when conditions are favorable.
2Reliability
If message 3 repetition is always applied, then message reception reliability is improved, but device complexity and protocol overhead increase
Solution Approach 1:
The patent applies message repetition selectively rather than universally. Specifically, repetition is applied only when beam failure is detected in certain downlink beams, while normal single transmission is used for other cases. This localized application of quality enhancement resolves the contradiction by providing reliability improvement only where actually needed, avoiding unnecessary complexity overhead.
Solution Approach 2:
The UE autonomously determines whether to repeat message 3 based on its own beam failure detection, without requiring complex network configuration or control signaling. The device self-manages the repetition decision based on local channel conditions, simplifying the overall protocol while maintaining reliability where needed.
3Reliability
If beamforming is not established, then connection setup time is reduced, but connection reliability deteriorates due to path loss at high carrier frequencies
Solution Approach 1:
The patent performs preliminary beam failure detection before message 3 transmission. The UE monitors downlink beam quality in advance and uses this information to determine whether to apply repetition. This preliminary action allows the system to prepare appropriate transmission strategies beforehand, ensuring reliability without unnecessary delays during the actual connection setup.
Data Source
AI summary
A random access procedure between a user equipment (UE) and a base station may include repetition of a random access message 3 conditioned on a property of a random access preamble to improve reception. The UE may transmit the random access preamble with coverage enhancement. The base station may detect a property of the random access preamble that indicates the coverage enhancement and determine a message 3 repetition parameter. The UE may transmit the random access message 3 with repetition based on the message 3 repetition parameter, and the base station may receive the random access message 3 based on the repetition parameter, thereby improving coverage of the random access message 3.