PRACH Repetition Control for Fair and Energy-Efficient Random Access
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In the 5G NR system, terminals supporting PRACH repetition face challenges in configuring resources for random access, leading to potential interference, unfair access opportunities, and energy waste due to varying coverage conditions and PRACH repetition.
Innovation Solution
The terminal determines the number of times to send a first random access message and selects target ROs based on configuration or RSRP thresholds, allowing flexible resource allocation and reducing unnecessary repetitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a terminal sends PRACH multiple times for coverage enhancement, then coverage is improved, but energy consumption increases and access fairness deteriorates
Solution Approach 1:
The terminal determines the number of PRACH transmission repetitions based on RSRP threshold comparisons. When RSRP is above the threshold, fewer repetitions are sent; when below, more repetitions are sent. This dynamic parameter adjustment optimizes energy consumption while maintaining coverage reliability.
Solution Approach 2:
The system dynamically adjusts the PRACH repetition count based on real-time RSRP measurements. The terminal adapts its transmission strategy by comparing current RSRP against configured thresholds, making the repetition number flexible rather than fixed, thereby balancing coverage and energy usage.
2Reliability
If a terminal sends PRACH multiple times for coverage enhancement, then coverage is improved, but access fairness deteriorates
Solution Approach 1:
Different terminals use different RSRP thresholds to determine their PRACH repetition counts. Terminals with poorer coverage (lower RSRP) use higher thresholds and send more repetitions, while terminals with better coverage use lower thresholds and send fewer repetitions. This adaptive parameter setting ensures fair access opportunities for all terminals regardless of their coverage conditions.
Solution Approach 2:
Each terminal independently determines its own PRACH repetition strategy based on its local RSRP measurement and applicable thresholds. This localized decision-making allows each terminal to optimize its access behavior according to its specific coverage conditions, achieving overall system fairness.
3Adaptability or versatility
If the network configures multiple candidate ROs, then resource flexibility is improved, but device complexity increases
Solution Approach 1:
The network divides the available RACH resources into multiple candidate ROs, each associated with specific RSRP thresholds. The terminal segments its selection process by comparing its RSRP measurement against these thresholds to identify the appropriate candidate RO, simplifying the decision process while maintaining resource flexibility.
Solution Approach 2:
The network pre-configures multiple candidate ROs with associated RSRP thresholds before random access occurs. This preliminary arrangement allows the terminal to quickly determine the appropriate RO by simple threshold comparison, reducing real-time processing complexity while maintaining flexible resource allocation.
Data Source
AI summary
A random access method is executed by a terminal that supports a physical random access channel (PRACH) repetition. The random access method includes: determining a number of times for sending a first random access message; determining one or more target random access channel (RACH) occasions (ROs) with a quantity equal to the number of times from one or more candidate ROs; and sending the first random access message to a network device at the one or more target ROs.