PRACH Beam Repetition Schemes for Random Access Coverage
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Solution Overview
Problem
The random access procedure in future radio communication systems, such as NR, is unclear, leading to potential deterioration in communication throughput without proper coverage improvement.
Innovation Solution
A terminal and base station are designed to determine and employ various transmission schemes for PRACH, including single and multiple beam repetitions, to enhance coverage during the random access procedure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If random access procedure is not optimized for coverage improvement, then communication throughput deteriorates, but implementing repetitions increases transmission time and resource consumption
Solution Approach 1:
The terminal dynamically selects between different transmission schemes (single transmission, repetitions with same beam, repetitions with different beams, or combination) based on coverage requirements and channel conditions. This dynamic adaptation allows the system to optimize between coverage reliability and transmission time by choosing the appropriate scheme for each random access attempt.
Solution Approach 2:
The random access procedure is segmented into multiple transmission attempts (repetitions) when coverage improvement is needed. Instead of a single transmission, the PRACH can be transmitted multiple times with different beam configurations, allowing the system to improve coverage reliability while managing transmission time through selective repetition.
2Reliability
If multiple beams are used for PRACH repetitions, then coverage is improved, but device complexity and beam management overhead increase
Solution Approach 1:
The terminal dynamically selects between single-beam and multi-beam transmission schemes based on coverage requirements. When coverage improvement is needed, multiple beams are employed; otherwise, simpler single-beam transmission is used. This dynamic selection reduces unnecessary beam management complexity while maintaining coverage improvement capabilities when required.
Solution Approach 2:
Different beam strategies are applied locally based on specific coverage needs. For terminals in poor coverage conditions, multiple beams with different spatial directions are employed to ensure at least one transmission succeeds. For terminals with good coverage, single-beam transmission suffices, reducing complexity. This localized application of beam management optimizes the balance between coverage and complexity.
3Reliability
If PRACH transmissions are repeated multiple times, then coverage improves, but resource consumption and interference increase
Solution Approach 1:
The terminal dynamically determines the number of repetitions and beam configurations based on measured channel conditions and coverage requirements. Instead of always transmitting multiple repetitions, the system adapts the transmission strategy to match actual needs, reducing energy consumption when coverage is already sufficient while maintaining reliability when needed.
Solution Approach 2:
The transmission parameters (number of repetitions, beam directions, beam widths) are changed based on coverage conditions. When coverage is poor, parameters are adjusted to increase repetitions and use diverse beam directions. When coverage is good, parameters are reduced to minimize energy consumption. This parameter adaptation resolves the contradiction between coverage improvement and energy loss.
Data Source
AI summary
A terminal according to one aspect of the present disclosure includes a control section that determines one transmission scheme from among a first transmission scheme for transmitting a physical random access channel (PRACH) without a plurality of repetitions, a second transmission scheme for transmitting the plurality of repetitions by using the same beam, a third transmission scheme for transmitting the plurality of repetitions by using a plurality of different beams, and a fourth transmission scheme for transmitting the plurality of repetitions by using the same beam and a plurality of different beams, and a transmitting section that transmits one or more PRACHs by using the transmission scheme. According to one aspect of the present disclosure, it is possible to improve coverage for random access procedure.