Random Access Preamble Power Ramping Counter Adjustment
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Solution Overview
Problem
In communication systems, particularly in LTE and NR, maintaining accurate power ramping counters for random access preambles is challenging, especially when beam switching occurs, and determining the maximum transmission times based on frequency band authorization is not effectively addressed.
Innovation Solution
A method for a terminal device to adjust the power ramping counter and set maximum transmission times of a random access preamble based on whether the beam changes and the frequency band authorization, ensuring power ramping remains consistent during beam switching and optimizing transmission attempts according to frequency band status.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the PREAMBLE_POWER_RAMPING_COUNTER is increased by 1 for every retransmission of the random access preamble, then the power ramping mechanism can ensure sufficient transmission power for successful access, but the counter cannot accurately track power ramping when beam switching occurs, leading to incorrect power calculations
Solution Approach 1:
The patent introduces dynamic behavior to the counter increment mechanism by making it conditional on beam consistency. The PREAMBLE_POWER_RAMPING_COUNTER is incremented by 1 only when the beam remains the same between transmissions, but does not increment when beam switching occurs. This dynamic conditional increment resolves the contradiction by adapting the counter behavior to the actual transmission conditions, ensuring accurate power tracking while supporting beam switching operations.
2Device complexity
If a single counter PREAMBLE_TRANSMISSION_COUNTER is used for both counting transmission times and power ramping, then the system structure remains simple, but the maximum transmission times of the random access channel are limited and cannot be independently optimized
Solution Approach 1:
The patent segments the single counter functionality into two independent counters: PREAMBLE_TRANSMISSION_COUNTER for tracking the number of transmission attempts and PREAMBLE_POWER_RAMPING_COUNTER for tracking power ramping steps. This segmentation allows each counter to be independently optimized and managed, enabling the system to set different maximum values for transmission times based on frequency band authorization while maintaining accurate power ramping tracking, thus improving transmission success rate without excessive complexity.
3Ease of operation
If the maximum transmission times of the random access preamble is set to a fixed value, then the system operation is simple, but the transmission resource utilization is inefficient when Listen Before Talk issues occur in unauthorized frequency bands
Solution Approach 1:
The patent changes the maximum transmission times parameter dynamically based on frequency band authorization status. When the transmission resource belongs to an unauthorized frequency band, the maximum transmission times is set to a larger second value to accommodate potential LBT failures and allow more retransmission attempts. When the resource belongs to an authorized frequency band, a smaller first value is used. This parameter adaptation optimizes transmission resource utilization for different frequency band conditions while maintaining manageable system operation.
Data Source
AI summary
Implementations of the present disclosure relate to a method for transmitting a random access preamble, and a terminal device. The method comprises: performing the i-th transmission of a random access preamble, i being a positive integer greater than 1; and if the i-th transmission of the random access preamble is performed by the same wave beam as the (i−1)-th transmission, incrementing the value of a power ramping counter of the random access preamble by 1.