PDCCH Decoding via Aggregation-Dependent CRC Masking
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Solution Overview
Problem
In wireless communication systems, particularly in LTE technology, user equipment (UE) faces challenges in accurately decoding the Physical Downlink Control Channel (PDCCH) due to problematic payload sizes and overlapping search spaces across different aggregation levels, leading to ambiguity in identifying allocated uplink resources.
Innovation Solution
The implementation of methodologies such as zero padding, aggregation level-dependent rate matching, and cyclic redundancy check (CRC) masking to facilitate accurate decoding of PDCCH, including the use of artificial intelligence to determine bit padding and scrambling sequences based on payload sizes and channel conditions, thereby reducing ambiguity and increasing decoding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PDCCH is transmitted with multiple aggregation levels to ensure reliable control signal delivery, then coverage and reliability are improved, but search spaces overlap and cause ambiguity in identifying allocated uplink resources
Solution Approach 1:
The patent applies preliminary action by pre-defining non-overlapping search space sets for different aggregation levels before transmission. The base station configures multiple search space sets with distinct resource locations, and the UE is provided with information about which search space set to monitor through RRC signaling. This preliminary configuration prevents overlap ambiguity before it occurs, allowing the UE to correctly identify uplink resources without confusion from multiple aggregation levels.
2Measurement precision
If UE performs blind detection across all aggregation levels to ensure accurate PDCCH decoding, then decoding accuracy is improved, but detection complexity and processing time increase
Solution Approach 1:
The patent applies segmentation by dividing the search space into multiple non-overlapping search space sets, each associated with specific aggregation levels. Instead of performing blind detection across all possible locations and aggregation levels simultaneously, the UE is configured to monitor specific search space sets through RRC signaling. This segmentation reduces the number of blind detection attempts required while maintaining decoding accuracy, as the UE only needs to search within its configured search space sets rather than the entire control region.
3Ease of operation
If standard CRC checking is used for PDCCH decoding verification, then error detection is simplified, but false alarm rates increase due to ambiguous aggregation levels
Solution Approach 1:
The patent applies local quality by associating different CRC masks with different search space sets and aggregation levels. Instead of using a single uniform CRC check, the UE applies specific CRC masks that correspond to the configured search space set. This local differentiation of CRC checking parameters reduces false alarms caused by aggregation level ambiguity, as each search space set has its own dedicated CRC verification method tailored to its specific aggregation levels.
Data Source
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AI summary
Downlink PDCCH is communicated in a manner that facilitates accurate decoding of the PDCCH by one or more user equipments. An aggregation level for each of the one or more UEs is identified. A scrambling sequences corresponding to the aggregation level for each of the one or more UEs is generated and used for scrambling cyclic redundancy check bits of PDCCH transmissions for the one or more UEs. The scrambled CRC bits are transmitted in the PDCCH transmissions to the one or more UEs.