Uplink Control Information Interspersing for Carrier Aggregation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing LTE carrier aggregation framework faces challenges in efficiently handling a large number of carriers, particularly in supporting up to 32 carriers, which results in increased HARQ-ACK bits and requires new PUCCH formats to improve uplink control information signaling, especially with the introduction of Rel-13 enhancements.
Innovation Solution
The proposed solution involves interspersing known and unknown uplink control information across information words, channel encoding, and transmitting these as codewords to improve decoding performance, using techniques like interleaving and error detection, and configuring serving cell indices to optimize codebook adaptation and reduce errors in HARQ-ACK feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of downlink carriers is increased to support up to 32 carriers, then the system capacity and peak data rates are improved, but the number of HARQ-ACK bits increases significantly to hundreds of bits, requiring new PUCCH formats and increasing device complexity
Solution Approach 1:
The patent segments the UCI payload into multiple parts by separating known UCI bits (for scheduled carriers) from unknown UCI bits (for non-scheduled carriers). This segmentation allows different encoding and transmission strategies for different parts of the control information, reducing the overall complexity of handling large payloads compared to treating all bits uniformly.
Solution Approach 2:
The patent applies preliminary action by having the base station pre-determine which UCI bits are known and which are unknown based on scheduling decisions before transmission. This pre-characterization of UCI bits enables optimized encoding strategies where known bits can be handled differently from unknown bits, reducing the complexity of the PUCCH format design for supporting up to 32 carriers.
2Quantity of substance
If the number of HARQ-ACK bits increases to support multiple carriers, then the uplink control information payload increases, but the reliability of decoding decreases due to increased error probability in large payload transmissions
Solution Approach 1:
The patent applies local quality by treating different portions of the UCI payload differently based on their characteristics. Known UCI bits (for scheduled carriers) are separated from unknown UCI bits (for non-scheduled carriers), allowing each portion to be encoded and transmitted with appropriate reliability measures. This local differentiation improves overall decoding reliability compared to uniform treatment of all bits.
Solution Approach 2:
The patent introduces an intermediary classification mechanism that categorizes UCI bits into known and unknown categories based on scheduling information. This intermediary classification allows the system to apply different error protection and decoding strategies to different bit categories, thereby improving the reliability of the overall UCI transmission despite the increased payload size.
3Adaptability or versatility
If codebook adaptation is based on the number of detected PDCCHs, then the codebook can be dynamically adjusted, but the UE may miss detecting PDCCHs leading to codebook divergence between UE and eNB and corrupted HARQ operations
Solution Approach 1:
The patent applies preliminary action by having the base station pre-determine the classification of UCI bits into known and unknown categories based on scheduling decisions before transmission. This pre-characterization allows the UE to construct its codebook with the same understanding of which bits are known, preventing codebook divergence that would occur with detection-based adaptation. The base station's preliminary classification ensures both sides use the same codebook assumptions.
Solution Approach 2:
The patent implements feedback by having the base station determine which UCI bits are known based on scheduling information, and this determination is implicitly feedback to the UE through the scheduling assignment itself. This feedback mechanism ensures both UE and eNB have synchronized understanding of the codebook structure, preventing the divergence issues that arise from detection-based adaptation where the UE may miss PDCCHs.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A wireless communication device (16) signals uplink control information for multiple different downlink carriers to a base station (20) in a wireless communication system (10). The device (16) in this regard intersperses uplink control information known by the base station (20) with uplink control information not known by the base station (20) across one or more information words that comprise uplink control information for multiple different downlink carriers. The device (16) channel encodes the one or more information words to obtain one or more codewords, and then transmits the one or more codewords to the base station (20) as an uplink control information report. The base station (20) correspondingly channel decodes the one or more codewords to obtain the one or more information words.