PRACH Preamble Repetition for Weak-Signal Random Access
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Solution Overview
Problem
Preamble sequences sent by user equipment in secluded areas, such as basements, experience significant signal loss, leading to decreased matching probability and access efficiency due to incorrect reception by base stations.
Innovation Solution
User equipment increases the number of repetitions of preamble sequences sent at specific resource locations within the PRACH, enhancing signal strength and improving matching probability at the base station.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If user equipment sends preamble sequence only once per subframe, then transmission resource usage is low, but signal strength at base station is insufficient leading to incorrect matching
Solution Approach 1:
The patent implements periodic transmission of preamble sequences by determining a quantity of repetition times based on link loss conditions. User equipment periodically retransmits the preamble sequence multiple times at predetermined resource locations when link loss exceeds a threshold, rather than sending it once. This periodic action ensures that at least one transmission reaches the base station with sufficient signal strength for correct matching, while controlling the number of repetitions based on actual channel conditions.
2Reliability
If user equipment increases repetition times of preamble sequence, then signal strength at base station improves, but transmission time and resource consumption increase
Solution Approach 1:
The patent dynamically adjusts the quantity of preamble sequence repetitions based on real-time link loss conditions. The user equipment determines whether to repeat the preamble sequence and how many times to repeat it based on the measured link loss compared to a threshold. This dynamic adaptation ensures that transmissions in poor conditions (basements, secluded areas) use more repetitions to guarantee reception, while transmissions in good conditions use fewer repetitions, optimizing the balance between reliability and time consumption for each specific scenario.
3Reliability
If user equipment sends preamble sequence multiple times, then matching probability increases, but base station processing complexity increases
Solution Approach 1:
The patent applies different transmission strategies to different local conditions by determining the quantity of preamble repetitions based on link loss thresholds. User equipment in secluded areas with high link loss automatically increases repetition times to ensure their signals reach the base station with sufficient strength. Meanwhile, user equipment in areas with good signal conditions uses standard single transmissions. This local quality approach ensures that the base station only needs to process multiple repetitions when necessary, reducing overall system complexity while maintaining high access success probability for difficult-to-reach users.
Data Source
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AI summary
Embodiments of the present invention provide a preamble sequence transmission method, apparatus, and system, which relate to the communications field and can enhance signal strength of a preamble sequence received by a base station, so as to increase a matching probability of the base station and increase efficiency of gaining access to the base station by user equipment. The method includes: acquiring system information or a physical broadcast channel PBCH that is broadcast by a base station, where the system information or the PBCH includes a preset physical random access channel PRACH, the preset PRACH includes m preset radio frames, and m is a positive integer; determining that a quantity of repetition times of a preamble sequence, which is used for random access, at a preset resource location of the preset PRACH is n, where 1 ≤ n ≤ 10m; and sending, at n preset resource locations of the preset PRACH, the preamble sequence to the base station.