NR Random Access Preamble Repetition for Beam Coverage Gaps
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently transmitting and receiving wireless signals, particularly in high-frequency New Radio (NR) systems, due to reduced cell coverage and beam quality degradation, which affect the random access procedure.
Innovation Solution
The proposed method involves transmitting RA preambles with the same index on random access channel occasions within a group, receiving a random access response by monitoring Physical Downlink Control Channel search spaces associated with this group, and transmitting an uplink signal based on time resources aligned with these search spaces, while considering beam quality and coverage supplementation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional random access procedure is used in high-frequency NR systems, then system simplicity is maintained, but cell coverage is reduced and beam quality degrades
Solution Approach 1:
The random access procedure is segmented into multiple stages with different preamble transmission strategies. The method divides the random access process into initial preamble transmission (using same index preambles) and potential retransmission stages (using different index preambles), allowing the system to adapt to beam quality and coverage requirements at different levels of complexity
Solution Approach 2:
The patent implements dynamic adaptation in the random access procedure by allowing UE to select different preamble index strategies based on beam quality conditions. The system transitions from static traditional procedures to dynamic procedures where preamble selection adapts to real-time beam quality measurements, improving reliability without fixed complexity
2Productivity
If preamble repetition is implemented, then random access efficiency is improved, but time resource consumption increases
Solution Approach 1:
The patent applies partial action by implementing preamble repetition only when necessary (when beam quality degradation is detected), rather than continuously repeating preambles. The system transmits preambles with same index initially, and only repeats with different indices if beam quality is insufficient, thus avoiding unnecessary time consumption while maintaining efficiency when needed
Solution Approach 2:
The method implements periodic action through structured preamble repetition patterns where preambles are transmitted in periodic cycles with different indices. This periodic structure allows efficient random access while controlling time consumption through defined repetition intervals and conditions
3Reliability
If beam quality degradation is addressed through preamble repetition, then connection reliability is improved, but processing complexity increases
Solution Approach 1:
The patent implements feedback mechanisms where the UE monitors beam quality and uses this information to determine whether to repeat preamble transmission with different indices. The feedback loop includes beam quality measurement, comparison with threshold values, and adaptive preamble selection, improving connection reliability through closed-loop control while managing processing complexity through condition-based actions
Data Source
AI summary
The present disclosure relates to a wireless communication system and particularly to a method and an apparatus therefor, the method comprising the steps of: transmitting an RA preamble on one RO among a plurality of ROs, wherein, on ROs in a first RO group among a plurality of RO groups, a plurality of RA preambles having the same index are transmitted; receiving, on the basis of having transmitted the plurality of RA preambles, RAR by monitoring a plurality of PDCCH search spaces linked to the first RO group; and transmitting an uplink signal corresponding to the RAR, wherein a time resource of each PDCCH search space linked to the first RO group is linked to each RO of the first RO group.