PRACH Occasion Multiplexing for Weak-Coverage Random Access
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing PRACH resource allocation schemes only support single PRACH transmission, lacking a method for configuring ROs for multiple PRACH transmissions, which is necessary for enhancing uplink coverage in areas with weak signal strength.
Innovation Solution
A mechanism for configuring multiple PRACH transmissions by time-domain, frequency-domain, or time-and-frequency-domain multiplexing of ROs, with specific positioning of PRACH occasions using identical or neighboring ROs mapping to SSBs, enabling consistent definition and improved detection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single PRACH transmission scheme is used, then the device complexity is low, but the uplink coverage is insufficient in weak signal areas
Solution Approach 1:
The PRACH transmission is divided into multiple separate transmissions instead of a single transmission. Each PRACH transmission uses a dedicated RO (RACH Occasion), allowing the UE to transmit multiple PRACHs in sequence to improve the probability of successful reception in weak coverage areas.
Solution Approach 2:
The system dynamically selects and configures multiple ROs for PRACH transmissions based on coverage requirements. The network can flexibly adjust the number of PRACH transmissions, RO configurations, and multiplexing schemes (FDM, TDM, or both) to adapt to different coverage scenarios and signal conditions.
2Reliability
If multiple PRACH transmissions are configured, then the uplink coverage is enhanced, but the resource allocation complexity increases
Solution Approach 1:
The RO configuration mechanism is designed to be universal and multi-functional, supporting both single and multiple PRACH transmissions through a unified configuration framework. The same configuration parameters and procedures are used regardless of whether one or multiple PRACH transmissions are required, simplifying the overall system design.
Solution Approach 2:
The system uses configurable parameters such as the number of PRACH transmissions, RO indices, and multiplexing types to control the behavior of multiple PRACH transmissions. By changing these parameters, the network can flexibly adjust the complexity and performance of the PRACH scheme without changing the underlying configuration mechanism.
3Use of energy by moving object
If multiple ROs are used for multiple PRACH transmissions, then the transmission energy is improved, but the frequency and time resource utilization becomes more complex
Solution Approach 1:
The system uses both frequency and time dimensions for resource multiplexing of multiple ROs. By utilizing FDM (frequency division multiplexing) and TDM (time division multiplexing) separately or in combination, the system can distinguish multiple PRACH transmissions in different frequency resources, time resources, or both, thereby managing resource complexity through dimensional separation.
4Measurement precision
If ROs are configured for multiple PRACH transmissions, then the detection accuracy is improved, but the signaling overhead increases
Solution Approach 1:
The network configures multiple ROs using existing RRC signaling parameters and procedures. By reusing and extending current configuration parameters (such as adding RO index lists and multiplexing type indicators), the system can convey multiple RO configurations without requiring entirely new signaling mechanisms, thereby limiting the increase in signaling overhead.
Data Source
AI summary
A physical random access channel transmitting method and apparatus, the method including: a terminal equipment transmits a second number of PRACHs on a first number of valid ROs, the first number of valid ROs being time-domain multiplexed, or the first number of valid ROs being frequency-domain multiplexed, or the first number of valid ROs being time-domain and frequency-domain multiplexed, and the first number and the second number being positive integers greater than or equal to 2.