RACH Response Mapping for Uplink Message Repetition Control
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Solution Overview
Problem
Conventional random access channel (RACH) techniques in wireless communications systems are deficient in ensuring correct reception of messages, leading to delayed or prevented UE-network communication due to sub-optimal channel conditions.
Innovation Solution
A base station indicates message repetition parameters to a user equipment (UE) through transmission parameters in a random access channel (RACH) response, enabling the UE to transmit uplink messages with configured repetitions based on mapping between transmission and repetition parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional RACH techniques are used, then the system maintains simplicity in message transmission, but message reception reliability deteriorates under sub-optimal channel conditions
Solution Approach 1:
The base station determines repetition parameters in advance based on channel conditions and includes them in the RAR message before the UE transmits uplink messages. This preliminary configuration allows the UE to perform repeated transmissions without real-time complexity, improving reliability while maintaining operational simplicity.
Solution Approach 2:
The patent introduces repetition parameters (number of repetitions, time interval, frequency hopping pattern) that dynamically change the transmission characteristics based on channel conditions. By modifying these parameters in the RAR message, the system adapts to sub-optimal channel conditions without requiring complex real-time processing at the UE.
2Reliability
If message repetitions are implemented without parameter indication, then transmission reliability improves, but system efficiency deteriorates due to unoptimized repetition configurations
Solution Approach 1:
The base station uses channel condition feedback and historical data to determine optimal repetition parameters, which are then communicated to the UE via the RAR message. This feedback mechanism ensures that repetition configurations are optimized for current channel conditions, maintaining high reliability while improving system efficiency through informed parameter selection.
Solution Approach 2:
The repetition parameters are made dynamic and adaptable rather than fixed. The base station can adjust the number of repetitions, time intervals, and frequency hopping patterns based on real-time channel assessments, allowing the system to efficiently respond to varying channel conditions without unnecessary overhead.
3Reliability
If repetition parameters are explicitly signaled in RAR, then message reception reliability improves, but signaling overhead increases
Solution Approach 1:
The RAR message structure is enhanced to include repetition parameters that serve multiple functions: they configure uplink message repetitions, indicate timing information, and provide frequency hopping patterns. This multi-functionality reduces the need for separate signaling messages, thereby improving reliability while minimizing additional signaling overhead.
Solution Approach 2:
The patent merges the repetition parameter indication with the existing RAR message structure rather than creating separate signaling channels. By combining multiple functions (repetition configuration, timing indication, frequency hopping patterns) into a single RAR message, the system achieves reliable message reception without proportionally increasing overhead.
4Reliability
If uplink message repetitions are transmitted, then communication reliability improves, but transmission latency increases
Solution Approach 1:
The patent implements periodic repeated transmissions with optimized time intervals between repetitions. By carefully selecting the periodicity and spacing of repetitions based on channel conditions, the system ensures reliable reception while minimizing the total time required for successful message delivery, thus reducing latency overhead.
Solution Approach 2:
The repetition parameters are pre-configured in the RAR message, allowing the UE to immediately begin optimized repetition transmissions without additional delays for parameter negotiation or real-time adjustments. This preliminary configuration reduces setup latency and enables efficient repeated transmissions from the outset.
Data Source
AI summary
Techniques and devices for wireless communications are described. A base station may indicate to a user equipment (UE) repetition parameters for an uplink message using transmission parameters in a response message of a random access channel (RACH) procedure. In some examples, the base station may transmit system information to the UE configuring a mapping between the transmission parameters and the repetition parameters, for example based on a repetition request or a capability indication in a random access request from the UE. The indications in the response message configuring uplink message repetitions may enable increased system efficiency and reduced latency at the UE, among other benefits.