RACH Preamble Construction Using Cyclic Prefix for Large Cell Coverage
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Solution Overview
Problem
Current methods for constructing a random access channel (RACH) struggle to effectively cover larger cell radii beyond 15km, requiring adaptive guard time and complex RACH structures, which increases hardware complexity and resource wastage.
Innovation Solution
A method for constructing a RACH preamble using a predetermined cyclic prefix (CP) and sequence length, independent of guard time, to support various cell radii, reducing hardware complexity and optimizing RACH structures for efficient coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If adaptive guard time is used to cover larger cell radii, then cell coverage is improved, but hardware complexity increases
Solution Approach 1:
The patent changes the time parameter by extending the cyclic prefix length to cover larger cell radii. By adjusting the CP length parameter to be sufficient for the maximum cell radius, the system achieves extended coverage without requiring adaptive guard time mechanisms, thus avoiding increased hardware complexity.
2Adaptability or versatility
If complex RACH structures are used to support various cell radii, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent creates a universal RACH structure where a single extended cyclic prefix configuration can serve multiple cell radius requirements. The extended CP structure functions universally for both small and large cell scenarios, eliminating the need for multiple specialized RACH structures and reducing overall system complexity.
Solution Approach 2:
The patent introduces dynamic selection of RACH preamble formats based on cell radius. The system can dynamically choose between normal CP and extended CP configurations, allowing adaptability to different cell sizes without requiring complex fixed structures for all scenarios.
3Area of stationary object
If extended cyclic prefix is used for large cell coverage, then cell radius coverage is improved, but resource wastage increases
Solution Approach 1:
The patent implements dynamic adaptation where the cyclic prefix length is adjusted based on the actual cell radius. For small cells, the normal CP length is used to avoid resource wastage, while for large cells, the extended CP length is activated. This dynamic adjustment ensures resources are optimally utilized without unnecessary wastage in small cell scenarios.
Data Source
Figure 1(a)~1(b)
Figure 2A~2B
Figure 3A~3B
AI summary
A wireless communication system is disclosed. A method for constructing a RACH preamble according to a cell radius of a base station (BS) irrespective of a guard time (GT) and a method for allocating the RACH preamble are disclosed. A method for constructing a preamble of a random access channel (RACH) includes acquiring time-length information of a predetermined cyclic prefix (CP) for each cell radius of a base station (BS), acquiring sequence time-length information of a single sequence or a repeated sequence, and constructing the preamble using the predetermined CP time-length information and the sequence time-length information, irrespective of a time length of a guard time (GT).