PRACH RO Set Indication Using Time Offset and Start RO
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Solution Overview
Problem
The existing PRACH mask index in wireless communication systems is limited in indicating RO sets, leading to conflicts and inefficiencies in PRACH transmissions with multiple preamble repetitions, particularly in NR systems.
Innovation Solution
A method for determining a start RO in an RO set based on a configured time offset, allowing for effective indication of RO sets using a PRACH mask index, even with a limited indication field, thereby reducing conflicts and enhancing coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a PRACH mask index is used to indicate an RO set, then the indication of RO sets can be achieved, but not all RO sets can be indicated and conflicts with other random access mechanisms occur
Solution Approach 1:
The patent segments the RO set indication process into two parts: the first part uses the PRACH mask index to indicate a starting RO, and the second part uses a time offset to determine the complete RO set. This segmentation allows the limited PRACH mask index to effectively indicate more RO sets by combining it with the time offset parameter, thereby resolving the contradiction between indication capability and indication completeness.
Solution Approach 2:
The patent introduces a time dimension (time offset) to the RO set indication process. Instead of relying solely on the PRACH mask index in the frequency domain, the solution adds a time-based dimension by defining a time offset from the starting RO to other ROs in the set. This dimensional expansion enables comprehensive indication of all RO sets without conflicts.
2Reliability
If multiple preamble repetitions are used in PRACH transmission, then coverage performance is enhanced, but resource conflicts and indication inefficiencies occur
Solution Approach 1:
The patent performs preliminary determination of the starting RO using the PRACH mask index before establishing the complete RO set with the time offset. This preliminary action allows the system to pre-allocate resources for multiple preamble repetitions in an organized manner, avoiding conflicts and ensuring efficient resource utilization while maintaining enhanced coverage performance.
Solution Approach 2:
The patent changes the parameter representation by introducing a time offset parameter that defines the relationship between ROs in terms of the number of SSBs. This parameter transformation enables the system to efficiently manage multiple preamble repetitions across different time resources, resolving the contradiction between coverage enhancement and transmission efficiency.
3Device complexity
If a limited indication field is used for PRACH mask index, then the field size is constrained, but effective indication of all RO sets becomes difficult
Solution Approach 1:
The patent introduces the time offset as an intermediary parameter that bridges the gap between the limited PRACH mask index and the complete RO set indication. The PRACH mask index serves as a mediator that indicates the starting point, while the time offset mediates the relationship between the starting RO and other ROs in the set. This intermediary mechanism enables comprehensive RO set indication within the constrained field size.
Solution Approach 2:
The patent implements a nested indication structure where the PRACH mask index provides the outer layer indication of the starting RO, and the time offset provides the inner layer indication of the relative positions of other ROs. This nested approach allows the limited PRACH mask index to effectively indicate a larger number of RO sets by combining it with the time offset information.
Data Source
AI summary
A method for wireless communication and an apparatus are provided. One example method includes: transmitting a first physical random access channel (PRACH) transmission on a first PRACH occasion (RO) set, wherein a first time offset is a time offset between each two successive RO sets in the plurality of RO sets; and determining a start RO in the first RO set based at least in part on whether the first time offset is configured.