Wireless Control Channel Recovery Using CRC Syndrome Correction
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Solution Overview
Problem
In wireless communication networks, particularly in UMTS systems, user equipment (UE) experiences desense due to interference from secondary radio access technologies, leading to corruption or loss of data from control channels, such as HS-SCCH, which existing methods struggle to recover effectively.
Innovation Solution
A method and apparatus that utilize cyclic redundancy check (CRC) bits to recover corrupted codewords by computing syndromes, determining error patterns, and forming linear systems to estimate and remove error patterns from decoded codewords, thereby recovering the original codeword even when significant portions of the CRC and information bits are lost or corrupted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional decoding methods are used for control channels, then the decoding process is simple and fast, but the decoding fails when CRC bits are corrupted due to desense interference
Solution Approach 1:
The decoding process is segmented into multiple stages: initial decoding attempt, syndrome calculation, error pattern detection, and iterative correction. This segmentation allows the system to handle corrupted CRC bits systematically by breaking down the complex recovery task into manageable steps, improving reliability without overwhelming complexity
Solution Approach 2:
The patent performs preliminary actions by calculating syndromes and identifying error patterns before final decoding confirmation. This preliminary analysis enables the system to detect and correct errors proactively, ensuring reliable decoding even when CRC bits are corrupted, before proceeding to final data extraction
2Adaptability or versatility
If the UE simultaneously communicates with multiple networks using different RATs, then the communication capability is enhanced, but receiver desensitization occurs causing control channel data loss
Solution Approach 1:
The patent converts the harmful effect of desense-induced errors into a beneficial outcome by using syndrome calculation to identify and correct the exact error patterns. Instead of treating error correction as a separate function, the method integrates it into the decoding process, turning the presence of errors into an opportunity for systematic recovery and improving control channel reception reliability despite multi-network operation
Solution Approach 2:
The syndrome calculation acts as an intermediary between the received corrupted codeword and the final decoded output. This intermediary step identifies error patterns without requiring retransmission, enabling the system to bridge the gap between corrupted reception and reliable decoding, thus maintaining control channel reliability during simultaneous multi-RAT communication
3Measurement precision
If CRC bits are used for error detection, then the error detection capability is improved, but the CRC verification fails when CRC bits themselves are corrupted
Solution Approach 1:
The patent applies partial action by performing syndrome calculation on only the information bits portion of the codeword, excluding the CRC bits. This partial processing allows error pattern identification without being affected by potential CRC corruption, enabling the system to maintain error detection precision while ensuring CRC verification reliability by not relying on potentially corrupted CRC bits for the initial error analysis
Data Source
AI summary
Aspects of the present disclosure provide an apparatus and methods for recovering data from a control channel in wireless communications. An apparatus decodes a CRC appended codeword to obtain a decoded codeword, and computes a first syndrome of the decoded codeword utilizing a parity check matrix. If the first syndrome is non-zero, The apparatus determines a location S and a length K of an error pattern in bits of the decoded codeword, an index set ε based on the values of S and K. A linear system is formed based on the parity check matrix and the error pattern in accordance with the index set ε. The apparatus determines a solution of the linear system, wherein the solution includes an estimated error pattern. A recovered codeword can be determined by removing the estimated error pattern from the decoded codeword.