PDCCH Decoding Using Known DCI Bits to Prune Codeword Candidates
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Solution Overview
Problem
Existing methods for decoding Physical Downlink Control Channels (PDCCH) in wireless communications face challenges in efficiently utilizing known DCI bits to improve decoding performance.
Innovation Solution
The method involves identifying known bits in the DCI by comparing previous DCI messages and reducing the number of candidate code words based on these known bits, utilizing techniques such as successive cancellation list decoding and linear decomposition of polar codes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional a priori probabilistic measures are used for PDCCH decoding, then the decoding process can be simplified, but decoding accuracy deteriorates in scenarios where such measures are insufficient or not directly applicable
Solution Approach 1:
The patent identifies and marks certain DCI bits as known bits before the decoding process begins. By performing this preliminary identification of known bit positions, the decoder can use this information during the decoding process to improve accuracy without significantly increasing overall complexity. The known bits are identified based on DCI format specifications and previous decoding results.
Solution Approach 2:
The patent applies different decoding strategies to different parts of the DCI message. Specifically, known bits are treated with special handling during the decoding process, while unknown bits follow conventional decoding procedures. This localized differentiation allows the system to improve accuracy in critical areas without applying complex measures throughout the entire decoding process.
2Measurement precision
If all candidate code words are evaluated during decoding, then decoding accuracy is maximized, but the number of operations and time required increases significantly
Solution Approach 1:
The patent extracts and removes candidate code words that are inconsistent with the known bits from the set of candidates to be evaluated. By taking out these invalid candidates early in the process, the decoder avoids performing unnecessary operations on them, thereby reducing the total number of operations and decoding time while maintaining accuracy by focusing only on valid candidates.
Solution Approach 2:
Instead of evaluating all possible candidate code words, the patent performs partial evaluation by limiting the candidate set to those consistent with known bits. This partial action approach achieves sufficient decoding accuracy without the excessive computational effort required to evaluate every possible candidate, thus optimizing the trade-off between accuracy and time.
3Reliability
If known bit positions are identified and utilized during PDCCH decoding, then decoding performance is improved, but the complexity of the decoding algorithm increases
Solution Approach 1:
The patent performs the complex task of identifying known bit positions in advance, before the main decoding process. This preliminary identification, based on DCI format specifications and previous decoding results, allows the main decoding algorithm to simply use the pre-identified known bits without implementing complex identification logic, thereby improving performance while keeping the main algorithm relatively simple.
Solution Approach 2:
The system uses its own previous decoding results and DCI format knowledge to identify known bits, essentially serving itself. This self-service approach allows the decoder to improve its own performance by utilizing information already available in the system without requiring external assistance or significantly increasing algorithmic complexity.
4Device complexity
If conventional decoding methods are used without utilizing known DCI bits, then the decoding process remains simple, but the success rate of decoding decreases in low signal power or unstable environments
Solution Approach 1:
The patent prepares known bit information in advance based on DCI format specifications and previous decoding results. This preliminary preparation provides the decoder with additional reliable information that can be used in challenging conditions, thereby improving the decoding success rate without requiring a complete redesign of the decoding process and maintaining relative simplicity.
Solution Approach 2:
The patent uses known bit information as a form of cushioning or protection against decoding failures in difficult conditions. By having this additional reliable information available beforehand, the system creates a buffer that helps maintain decoding success rates in low signal power or unstable environments without significantly increasing complexity.
Data Source
AI summary
Provided is a method of decoding, the method including receiving, by a user equipment (UE), a downlink control information (DCI) that is encoded, identifying, by the UE, a first bit position of the DCI as a known bit, and reducing a number of candidate code words for the DCI based on the known bit.