CCE Aggregation Level Handling in PDCCH Blind Decoding
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Solution Overview
Problem
Wireless communication systems face confusion in control channel element (CCE) aggregation levels, leading to inefficiencies in resource allocation and potential errors in decoding control information.
Innovation Solution
A method for processing physical downlink control channels (PDCCH) by user equipment (UE) involves receiving and performing blind decoding of CCEs, recognizing the CCE aggregation level, and associating resource mapping schemes with this level to allocate appropriate uplink resources for single antenna or multiple input multiple output (MIMO) transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If blind decoding is performed on multiple CCE aggregation levels, then the probability of successful control information detection is improved, but the decoding complexity and processing time increase
Solution Approach 1:
The patent segments the blind decoding process by dividing CCE candidates into different aggregation level groups (L=1, L=2, L=4, L=8). The UE performs decoding sequentially or selectively based on these segments rather than attempting all candidates simultaneously, reducing overall complexity while maintaining detection probability.
Solution Approach 2:
The patent applies preliminary actions by first decoding CCE candidates at higher aggregation levels (L=4, L=8) before attempting lower aggregation levels (L=1, L=2). This preliminary decoding approach leverages the fact that higher aggregation levels have better signal quality and are more likely to succeed first, reducing the total number of decoding attempts needed.
2Reliability
If CCE aggregation level is increased for robust transmission, then the reliability of control channel is improved, but the available resources for other transmissions decrease
Solution Approach 1:
The patent implements dynamic CCE aggregation level selection where the base station adapts the aggregation level based on current channel conditions, UE capability, and traffic requirements. This dynamic adjustment allows the system to use higher aggregation levels only when necessary for reliability, thereby optimizing resource utilization across different transmission scenarios.
Solution Approach 2:
The patent changes the CCE aggregation level parameter based on channel quality indicators and transmission requirements. By adjusting this parameter dynamically rather than using a fixed high aggregation level, the system achieves reliable control channel transmission while preserving resources for other transmissions when channel conditions permit.
3Productivity
If multiple PUCCH resources are allocated for MIMO transmission, then the uplink capacity is improved, but the resource allocation complexity increases
Solution Approach 1:
The patent uses the PDCCH and downlink control information as an intermediary to convey resource allocation instructions to the UE. Instead of requiring complex UE-side resource allocation decisions, the base station acts as an intermediary that determines and signals the appropriate PUCCH resources, simplifying UE complexity while enabling multiple resource allocation for MIMO.
Solution Approach 2:
The patent performs preliminary resource allocation through downlink control signaling before uplink transmission. The base station pre-allocates and signals multiple PUCCH resources to the UE via PDCCH, allowing the UE to simply follow the predetermined allocation rather than independently managing complex resource selection, thus increasing uplink capacity without proportionally increasing UE complexity.
Data Source
AI summary
The present invention relates to a wireless communication system. In particular, the present invention relates to a method for handling physical downlink control channels (PDCCHs) in a user equipment, the method comprising: receiving a plurality of control channel elements (CCEs) from a base station; performing blind decoding of the plurality of CCEs in CCE aggregation units; and identifying a CCE aggregation level used for the PDCCH transmission, on the basis of the blinding decoding result, wherein the CCE aggregation level is relevant resource mapping of the control information included in the PDCCH.