NR Random Access Preamble Power Mapping for Unlicensed PUSCH
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Solution Overview
Problem
In the context of a New Radio (NR) system, the determination of power for sending a Physical Uplink Shared Channel (PUSCH) when multiple preambles are sent in a random access procedure on an unlicensed spectrum is not clearly specified, leading to potential delays due to repeated Listen Before Talk (LBT) failures.
Innovation Solution
A method where a network device sends indication information to a terminal device indicating a random access preamble, allowing the terminal device to determine the power for sending the PUSCH based on the transmission power of a selected preamble, using a preset corresponding relationship.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple terminals perform random access simultaneously on the same carrier, then access efficiency is improved, but message collision probability increases
Solution Approach 1:
The patent divides the random access process into two independent stages: MsgA transmission on uplink carrier and MsgB reception on downlink carrier. This segmentation allows terminals to access different carriers without interfering with each other, reducing collision probability while maintaining access efficiency. The uplink carrier handles access requests while the downlink carrier handles responses, separating the traffic flows.
Solution Approach 2:
The patent introduces a new dimension by implementing random access on separate uplink and downlink carriers instead of using the same carrier for both directions. This dimensional separation in the communication spectrum allows simultaneous access operations without interference, effectively resolving the collision problem while improving overall access throughput.
2Device complexity
If message timing advance is not adjusted for different carriers, then device complexity is reduced, but message timing alignment deteriorates
Solution Approach 1:
The patent applies different timing advance adjustments locally to each carrier based on its specific propagation characteristics. The terminal receives separate timing advance values for the first carrier (used for MsgA transmission) and the second carrier (used for MsgB reception), allowing optimal timing alignment on each carrier without increasing overall system complexity.
Solution Approach 2:
The network device provides feedback in the form of timing advance adjustments to the terminal for each carrier. This feedback mechanism allows the terminal to dynamically adjust its transmission timing based on actual channel conditions, ensuring precise timing alignment while keeping the adjustment process automated and simple.
Data Source
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AI summary
The embodiments of the present application relate to a random access method, a terminal device and a network device. The method comprises: a terminal device receiving indication information sent by a network device, wherein the indication information is used for indicating at least one random access preamble from among multiple random access preambles, and the multiple random access preambles correspond to a receiving window of a random access response; and the terminal device determining, according to the transmission power of a first random access preamble from among the at least one random access preamble, the power for sending a physical uplink shared channel (PUSCH). According to the random access method, the terminal device and the network device in the embodiments of the present application, when sending multiple random access preambles on an unlicensed spectrum, the terminal device can determine the power for sending a PUSCH.