Base Station-UE Synchronization Using Repetitive CP Codewords
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In mobile communication systems, the existing synchronization methods require excessive computing resources and time for cell search due to the need to decode and compute metrics for a large number of codewords, especially in non-hierarchical synchronization channels, where frame timing and cell ID detection are performed from SCH signals within a frame.
Innovation Solution
A method using repetitive cyclically permutable (RCP) codewords is introduced, where each codeword has distinct cyclic shifts and a repetitive structure, allowing for efficient decoding by reducing the number of metrics to be computed and utilizing diversity combining, thereby simplifying the detection of frame synchronization and cell ID.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fully non-hierarchical SCH is used to detect cell ID and frame synchronization from SCH signals within a frame, then frame timing and cell ID detection can be performed without hierarchical cell ID grouping, but the UE needs to decode and compute metrics for 512 codewords and their cyclic shifts at once, which consumes excessive computing resources and power in the UE and prolongs the cell search time
Solution Approach 1:
The patent divides the 512 codewords into multiple groups (e.g., 8 groups of 64 codewords each). Instead of decoding all 512 codewords simultaneously, the UE performs sequential decoding across multiple SCH periods, where each period decodes one group of 64 codewords. This segmentation reduces the per-period computational burden from 512 codewords to 64 codewords, significantly lowering instantaneous decoding complexity and power consumption while maintaining the ability to detect all cell IDs and frame timings.
Solution Approach 2:
The patent utilizes the periodic transmission of SCH signals to structure the cell search process. The UE performs one group of codeword decodings per SCH period, leveraging the periodic nature of SCH transmissions to distribute the decoding workload over multiple periods. This periodic approach allows the system to maintain comprehensive cell search capability while reducing the computational load in each individual period, thereby lowering power consumption and enabling more efficient cell search operations.
2Reliability
If 512 codewords and their cyclic shifts are decoded and computed at once for cell ID detection, then all cell IDs can be detected continuously for mobility support, but the exhaustive procedure becomes overly tedious and consumes excessive computing resources and power in the UE
Solution Approach 1:
The patent segments the exhaustive decoding of 512 codewords into multiple smaller decoding tasks, with each SCH period handling one group of 64 codewords. This segmentation maintains the reliability of cell ID detection by ensuring all 512 codewords are eventually decoded, while distributing the computational workload over time to reduce instantaneous power consumption and avoid excessive energy usage in a single decoding operation.
Solution Approach 2:
The patent performs preliminary decoding of codeword groups in sequential SCH periods before completing the full cell search. By breaking down the exhaustive decoding into preliminary steps that process one group at a time, the system maintains detection reliability while reducing the energy burden on the UE, allowing mobility support to continue with manageable power consumption levels.
3Loss of information
If a large set of codewords is used to include cell IDs and additional cell-specific information (channel bandwidth, number of antennas, cyclic prefix lengths), then comprehensive cell search information can be obtained, but even larger sets of codewords need to be efficiently decoded
Solution Approach 1:
The patent segments the decoding of large codeword sets containing comprehensive cell-specific information into multiple groups processed over successive SCH periods. This segmentation allows the UE to decode one group of 64 codewords per period, maintaining access to all cell-specific information (channel bandwidth, number of antennas, cyclic prefix lengths) while reducing the instantaneous decoding complexity from handling all codewords at once to handling manageable groups sequentially.
Solution Approach 2:
The patent leverages the periodic SCH transmission structure to distribute the decoding of comprehensive codeword sets across multiple periods. Each period contributes to decoding a portion of the total codeword set, allowing the system to maintain complete cell-specific information while managing decoding complexity through periodic processing. This approach enables efficient handling of large codeword sets by breaking them into periodic decoding tasks.
Data Source
AI summary
Methods and apparatus are provided for facilitating synchronization between a base station (BS) and a user equipment (UE) in a mobile communication system. The UE receives a synchronization signal originated by the BS. The synchronization signal is encoded with a selected cyclically permutable (CP) codeword. Encoding of the synchronization signal is facilitated by a repetitive cyclically permutable (RCP) codeword derivable from the selected CP codeword. The RCP codeword has a plurality of codeword elements each associated with a value, the value of at least one codeword element in the RCP codeword being repeated in another codeword element position in the RCP codeword. And the synchronization signal is decoded in accordance with repetitive structure of the RCP codeword.