LTE Random Access Preamble Selection for High-Speed Mobility
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Solution Overview
Problem
The current LTE system's random access technology cannot simultaneously support high-speed terminal movement and larger cell coverage radius due to the limited cyclic shift values in the restricted set, which restricts cell coverage.
Innovation Solution
A method that selects a random access preamble format based on a preset cell coverage radius target value, determines if the restricted set of cyclic shift quantities meets this requirement, and if not, chooses a cyclic shift quantity from the unrestricted set to generate a random access signal, ensuring the terminal can achieve a greater cell coverage radius in high-speed mobile environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the restricted set of cyclic shift quantities is used to withstand frequency offset in high-speed movement, then the terminal can operate in high-speed mobile environment, but the cell coverage radius is limited to a smaller value
Solution Approach 1:
The patent dynamically selects between restricted and unrestricted cyclic shift quantity sets based on the terminal's movement state. When the terminal is in high-speed mobile environment, the system determines whether to use the restricted set (for frequency offset compensation) or the unrestricted set (for larger cell coverage), making the cyclic shift quantity selection adaptive rather than static.
Solution Approach 2:
The patent changes the parameter of cyclic shift quantity from a fixed restricted set to a flexible selection between restricted and unrestricted sets. By modifying the cyclic shift quantity parameter based on movement state and coverage requirements, the system can achieve either frequency offset withstand capability or larger cell coverage radius as needed.
2Length of stationary object
If the unrestricted set of cyclic shift quantities is used to increase cell coverage radius, then the terminal can achieve larger cell coverage, but the frequency offset in high-speed mobile environment cannot be effectively withstood
Solution Approach 1:
The system dynamically adjusts the cyclic shift quantity selection based on the terminal's movement state. When frequency offset compensation is needed, it switches to the restricted set; when cell coverage expansion is the priority, it uses the unrestricted set, making the system adaptive to different operational requirements.
Solution Approach 2:
The patent modifies the cyclic shift quantity parameter by allowing selection from either the restricted set or unrestricted set based on system requirements. This parameter change enables the system to optimize between frequency offset resistance and cell coverage radius depending on the operational context.
3Reliability
If the maximum cyclic shift quantity value in the restricted set is used, then the frequency offset compensation is maximized, but the cell coverage radius remains limited
Solution Approach 1:
The system dynamically determines whether to use the maximum cyclic shift quantity from the restricted set or to switch to the unrestricted set based on the terminal's movement state and coverage requirements. This dynamic decision-making allows optimization of either frequency offset compensation or cell coverage radius as the priority.
Solution Approach 2:
The patent changes the cyclic shift quantity parameter by enabling selection from the unrestricted set when the restricted set's maximum value is insufficient for the desired cell coverage radius, while still maintaining the option to use the restricted set for optimal frequency offset compensation.
Data Source
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AI summary
A random access method and random access system for a terminal in a high-speed mobile environment are provided. Wherein, the method comprises: selecting a random access preamble format according to a preset cell coverage radius target value; judging whether using a restricted set of cyclic shift quantities pre-configured satisfies a requirement of the cell coverage radius target value under the selected random access preamble format; if not satisfying, selecting a cyclic shift quantity which satisfies the requirement of the cell coverage radius target value from a unrestricted set of the cyclic shift quantities pre-configured ; and generating a random access signal according to the cyclic shift quantity and a pre-configured mother code, and performing access using the random access signal. Through the above-mentioned technical scheme, the embodiment of the present document provides a more perfect random access method and random access system for a terminal in a high-speed mobile environment.