Adaptive PRACH Configuration for Lower UE Access Latency
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Solution Overview
Problem
Current wireless communication systems, such as 5G, face challenges in efficiently adapting the configuration of random access channel (RACH) occasions (ROs) due to the time and overhead required for updating PRACH configurations, leading to increased network power consumption and latency in UE access.
Innovation Solution
The proposed solution involves adapting the PRACH configuration by increasing the number of ROs available for a duration after receiving an adaptation signal, using implicit or explicit indications like paging messages or DCI, allowing for reduced latency and power consumption by temporarily applying an updated RO pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the PRACH configuration is updated to increase the number of ROs, then the latency for UE access is reduced, but the signaling overhead and complexity increase
Solution Approach 1:
The patent changes the parameters of the PRACH configuration dynamically by receiving indication information that specifies a time domain parameter (such as time offset or time window) to determine a second set of ROs. This allows the network to adjust the number and timing of ROs based on current conditions, reducing access latency when needed while maintaining flexibility to return to the default configuration when the adapted configuration is no longer needed.
Solution Approach 2:
The patent implements dynamic adaptation of the RO pattern by allowing the network entity to transmit indication information that modifies the PRACH configuration temporarily. The UE applies the adapted configuration for a specific duration or until a release indication is received, enabling the system to respond dynamically to changing traffic conditions and reduce access latency without permanently increasing signaling overhead.
2Adaptability or versatility
If the PRACH configuration is updated frequently, then the adaptability to traffic conditions is improved, but the network power consumption increases
Solution Approach 1:
The patent employs periodic monitoring where the UE monitors for indication information at specific intervals or at designated RO occasions. The network entity can transmit adaptation indications periodically or event-triggered, allowing the system to adapt to traffic conditions while avoiding continuous signaling that would increase power consumption. The UE only processes configuration changes when indication information is actually received.
Solution Approach 2:
The patent uses parameter-based adaptation where the network entity transmits indication information containing time domain parameters that define when the adapted ROs should be used. This allows for controlled, parameter-driven adaptation rather than continuous reconfiguration, enabling the system to respond to traffic conditions while limiting the frequency and impact of configuration updates on network power consumption.
3Productivity
If the number of ROs is increased temporarily, then the productivity of random access is improved, but the loss of time for configuration management increases
Solution Approach 1:
The patent applies preliminary action by having the network entity transmit the indication information in advance, before the UE needs to perform random access. The UE receives and stores the adapted RO configuration information ahead of time, so when random access is needed, the UE can immediately use the pre-configured ROs without additional configuration delays, thereby improving productivity while minimizing configuration management time.
Solution Approach 2:
The patent implements dynamic configuration adaptation where the UE transitions between the default RO pattern and the adapted RO pattern based on received indication information. The adaptation is applied for a specific time duration or until a release indication is received, allowing the system to quickly switch to a high-productivity configuration when needed and return to the default configuration afterward, minimizing the time spent in configuration management states.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described that provide for adaptation of a physical random access channel (PRACH) configuration to change a quantity of random access occasions (ROs) available for transmission of a random access message from a user equipment (UE) subsequent to receipt of a signal at the UE. The PRACH configuration may be adapted to provide an increased quantity of ROs for a time duration subsequent to the receipt of the signal at the UE. The timing for starting the adapted PRACH configuration may be at a start of a subsequent RO pattern within an association pattern period, at a start of a subsequent paging association pattern period, or a certain number of milliseconds or frames subsequent to the signaling that indicates the adapted PRACH configuration.