Cell Search Processing Load Reduction via Scrambling Code Segmentation
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Solution Overview
Problem
Conventional cell search methods in mobile stations require excessive calculation to identify scrambling codes, leading to inefficient processing during initial cell selection and handover.
Innovation Solution
A base station apparatus forms frames with pilot symbols multiplied by sequences from a sequence set corresponding to its scrambling code, and a mobile station receives these frames to detect frame timing and identify scrambling codes using correlation calculations, thereby reducing the number of code group candidates and alleviating processing load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If all code group candidates are used to identify scrambling code group in the second step, then scrambling code can be identified, but the amount of calculation increases significantly
Solution Approach 1:
The patent segments the code group identification process by dividing code groups into multiple sets, where each set contains a subset of code groups. The mobile station performs correlation calculation only with code groups within the identified code group set in the third step, rather than all code group candidates. This segmentation reduces the calculation amount while maintaining identification accuracy.
Solution Approach 2:
The patent applies local quality by making different parts of the code group identification process have different properties. In the second step, all code group candidates are used to identify the code group set. In the third step, only code groups within the identified set are used for scrambling code identification. This localized approach reduces overall calculation complexity.
2Ease of operation
If conventional three-step cell search method is used, then cell search can be performed, but processing time is increased due to excessive calculation
Solution Approach 1:
The patent segments the scrambling code identification process into two stages: first identifying the code group set in step two, then identifying the specific scrambling code within that set in step three. This segmentation allows the mobile station to reduce the search space significantly in step three, thereby reducing total processing time while maintaining cell search functionality.
Solution Approach 2:
The patent performs preliminary action by identifying the code group set in the second step before performing scrambling code identification in the third step. This preliminary identification of the code group set prepares the mobile station with reduced search candidates, enabling faster subsequent scrambling code identification and reducing overall cell search time.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces the computational burden in cell search processing, enabling faster and more efficient identification of the base station scrambling code, thus enhancing cell search performance.
Implementation Method 1
a correlation section that multiplies all the sequence candidates by the frame and calculates correlations
Data Source
AI summary
Provided are a base station device and a mobile station device, which can lighten a cell-search processing. The base station device includes a frame constitution unit for forming a frame, in which a pilot symbol multiplied by a base station scrambling code and a plurality of sequences contained in the corresponding sequence set is arranged in at least the head or tail, and a radio transmission unit for sending the formed frame. On the receiving side, the frame timing can be detected from the position of a pilot symbol contained in that frame. Since the base station scrambling code and the sequence set containing the sequences are made to correspond to each other, candidates can be narrowed to at most the base station scrambling codes of the number of the combinations of the sequences contained in the sequence set, by detecting the sequences multiplied by the pilot symbol.