GCL Sequence Subset Selection for Cellular Cell Search
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Solution Overview
Problem
Current cellular communication systems, such as LTE, face inefficiencies in cell search and acquisition due to the need to search for all possible Generalized Chirp-Like (GCL) sequences across various bandwidths, leading to increased complexity, resource demand, and suboptimal performance.
Innovation Solution
A cellular communication system that employs a subset of GCL sequences tailored to specific bandwidths, allowing for truncated sequences that maintain advantageous auto and cross-correlation properties, enabling efficient cell search and detection by focusing on a subset of sequences corresponding to the narrowest bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the user equipment searches for all possible GCL sequences across all bandwidths during cell search, then the cell detection reliability is improved, but the cell search time and resource demand increase significantly
Solution Approach 1:
The patent segments the cell search process into two distinct phases: initial cell search using only narrowest bandwidth GCL sequences for quick detection, followed by a second stage for verifying higher bandwidth sequences. This segmentation allows the system to achieve reliable cell detection without the prohibitive time cost of searching all sequences simultaneously, directly resolving the contradiction between detection reliability and search time.
Solution Approach 2:
The patent applies preliminary action by performing the initial cell search and detection using only the narrowest bandwidth GCL sequences before proceeding to search for higher bandwidth sequences. This preliminary detection phase establishes a baseline reliable detection mechanism that avoids the time-consuming exhaustive search, thereby reducing cell search time while maintaining adequate detection reliability through the two-stage approach.
2Reliability
If the system uses full-length GCL sequences for all bandwidths, then the auto-correlation and cross-correlation properties are optimized, but the complexity of sequence management and search increases
Solution Approach 1:
The patent applies local quality by using different GCL sequence lengths tailored to specific bandwidth requirements. Instead of uniformly using full-length sequences across all bandwidths, the system employs appropriate sequence lengths locally matched to each bandwidth scenario, maintaining optimal correlation properties for each specific case while reducing overall system complexity through this differentiated approach.
Solution Approach 2:
The patent changes the parameter of sequence length based on bandwidth requirements. By adjusting the GCL sequence length parameter to match the specific bandwidth being searched (shorter sequences for narrowest bandwidth, full-length for higher bandwidths), the system maintains optimized correlation properties for each scenario while avoiding the complexity of managing all possible sequence lengths simultaneously through the two-stage search methodology.
3Ease of operation
If the broadcast control channel is limited to the narrowest bandwidth window, then the cell search process is simplified, but the flexibility for higher bandwidth operations is reduced
Solution Approach 1:
The patent applies dynamics by making the bandwidth search capability adaptive rather than static. The system dynamically adjusts the search bandwidth based on detection results: starting with the narrowest bandwidth for simple initial detection, then transitioning to higher bandwidth searches when needed. This dynamic approach maintains ease of operation through the simplified initial search while preserving bandwidth flexibility through the conditional second-stage search capability.
Data Source
AI summary
A cellular communication system employs a plurality of bandwidths. The cellular communication system comprises a plurality of base stations (101, 103) each of which transmits a reference signal comprising a Generalised Chirp-Like, GCL, sequence. The length of the GCL sequence is dependent on the bandwidth employed by the base station (101, 103). A sequence generator (105) provides a first subset of GCL sequences for a first bandwidth selected from a set of possible GCL sequences for the first bandwidth in response to properties of a sub-sequence of GCL sequences. The sub-sequence has a length corresponding to a different bandwidth. Sequence processors (107, 109) select GCL sequences for base stations (101, 103) employing the first bandwidth from the first subset of GCL sequences. The invention exploits characteristics of GCL sequences to enable, facilitate or improve multiple bandwidth operation.