Multi-PRACH Transmission Triggering for Random Access Coverage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The 3GPP Release 18 does not address the issue of triggering multi-PRACH transmission for improved coverage in wireless communication networks.
Innovation Solution
A method and apparatus for determining and triggering multi-PRACH transmission based on specific conditions, including BWP configuration, enabled state, and RSRP thresholds, to enhance resource utilization and transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If single PRACH transmission is used, then device complexity is low, but coverage is insufficient
Solution Approach 1:
The single PRACH transmission is segmented into multiple PRACH transmissions (first PRACH transmission and second PRACH transmission) with different power levels. The first transmission uses normal power while the second uses enhanced power, allowing the system to overcome coverage limitations without requiring complex device architecture changes.
Solution Approach 2:
The transmission power is made dynamic through a power adjustment mechanism. The network device configures power adjustment parameters (alpha, beta_offset, msg3_delta) that enable the terminal to dynamically adjust the power of the second PRACH transmission based on RSRP measurements and configured thresholds, resolving the contradiction between coverage enhancement and device complexity.
2Productivity
If multiple PRACH transmissions are performed, then resource utilization improves, but triggering mechanism complexity increases
Solution Approach 1:
The network device performs preliminary configuration by pre-defining triggering conditions and power adjustment parameters before the actual random access procedure. The terminal device receives and stores these configurations (RSRP thresholds, alpha values, beta offsets) in advance, so that when random access is needed, the triggering decision can be made quickly based on pre-established rules rather than complex real-time calculations.
Solution Approach 2:
A feedback mechanism is implemented where the terminal measures RSRP of downlink reference signals and compares it against configured thresholds to determine whether to trigger the second PRACH transmission. The network device also provides feedback through downlink messages to indicate whether the second transmission should be performed, creating a closed-loop control system that optimizes resource utilization while managing complexity.
3Productivity
If power adjustment is applied to second PRACH transmission, then transmission efficiency improves, but energy consumption increases
Solution Approach 1:
The power adjustment is achieved by changing the power parameter (using configured offsets like beta_offset and msg3_delta) rather than fundamentally altering the transmission mechanism. This allows efficient power scaling where the second PRACH transmission uses adjusted power only when necessary (based on RSRP conditions), improving transmission efficiency for edge users while avoiding unnecessary energy consumption for users with good signal conditions.
Solution Approach 2:
The power adjustment is applied partially - only to the second PRACH transmission under specific triggering conditions (low RSRP, failed first transmission), rather than to all transmissions unconditionally. This selective application of excessive power only when and where needed optimizes the trade-off between transmission efficiency and energy consumption, avoiding wasteful energy use while ensuring successful access when required.
Data Source
AI summary
A multi-PRACH transmission method includes: determining a triggering condition for a multi-PRACH transmission; and triggering the multi-PRACH transmission according to the triggering condition for the multi-PRACH transmission, in which the multi-PRACH transmission is used to indicate that the terminal performs multiple PRACH transmissions when sending Msg1 or MsgA for a random access.