Extended Cell Random Access Preamble Structure Design
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Solution Overview
Problem
Conventional random access preamble structures for extended cell radii fail to consider maximum round trip delay, leading to detection performance deterioration in the frequency domain due to insufficient cyclic prefix length, resulting in incomplete signal reception.
Innovation Solution
The proposed solution involves maintaining the preamble sequence part length equal to that of a standard random access preamble structure and extending the cyclic prefix and guard time according to the maximum round trip delay, with the option of using a repetitive preamble structure for improved detection in extended cell radii, ensuring sufficient preamble energy by multiplying the preamble duration or cyclic prefix and guard time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the cyclic prefix length is maintained equal to the standard preamble structure, then the device complexity is reduced, but the detection precision deteriorates when round trip delay exceeds CP length
Solution Approach 1:
The patent changes the parameter of cyclic prefix length from the standard value to an extended value that accounts for maximum round trip delay in extended cell radii. Specifically, the CP length is extended to be at least the sum of the maximum round trip delay and the maximum delay spread, ensuring that delayed signals are properly captured and detected in the frequency domain.
2Adaptability or versatility
If only guard time is extended while maintaining standard CP length, then the adaptability to extended cell radius is improved, but the signal reception completeness deteriorates when round trip delay exceeds CP length
Solution Approach 1:
The patent extends the cyclic prefix length parameter to accommodate the maximum round trip delay in extended cell radii. The CP length is set to be at least the sum of the maximum round trip delay and the maximum delay spread, ensuring that signals experiencing maximum delay are still fully captured within the CP period, thus maintaining signal reception completeness.
3Measurement precision
If the cyclic prefix is extended to account for maximum round trip delay, then the detection precision in frequency domain is improved, but the duration of the preamble structure increases
Solution Approach 1:
The patent changes the CP length parameter to be at least the sum of maximum round trip delay and maximum delay spread. This extension ensures that delayed signals are properly captured, improving detection precision in the frequency domain, while the guard time is also extended to maintain the overall structure integrity for extended cell radii.
Data Source
AI summary
Provided is a method of forming a random access preamble structure for an extended cell radius in a cellular system, the method including: generating a cyclic prefix (CP), which is the sum of a maximum delay spread and the maximum round trip delay according to the extended cell; generating a preamble sequence part. The method is used to form a preamble structure for an extended cell radius from among random access preamble structures transmitted when initial synchronization is achieved, when synchronization is lost, or when a handover is performed, during a random access process of the cellular system.