PCell HARQ-ACK Decoding via SCell Resource Allocation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wireless communication systems employing carrier aggregation, the primary cell (PCell) faces challenges in accurately receiving Hybrid Automatic Repeat Request-Acknowledgment (HARQ-ACK) feedback bits from the secondary cell (SCell) due to high latency in the X2 interface, leading to uncertainties in resource allocation and decoding of HARQ-ACK bits.
Innovation Solution
The solution involves configuring the PCell and SCell to use maximum allowable HARQ-ACK bits, accompanied by System Frame Number (SFN) and subframe number, to ensure correct decoding of HARQ-ACK feedback, even if the SCell has no transmission, by setting parameters W DAI UL and V DAI , c DL to assume all subframes have transmission, thereby maximizing the number of HARQ-ACK bits used by the user terminal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the PCell uses standard HARQ-ACK feedback reception with X2 interface communication, then the system maintains normal inter-cell coordination, but the high latency in the X2 interface causes uncertainties in resource allocation and decoding of HARQ-ACK bits
Solution Approach 1:
The PCell determines the number of HARQ-ACK bits in advance based on downlink resource allocation information received from the SCell, before the actual HARQ-ACK feedback is transmitted. This preliminary determination of feedback bit count eliminates the need for real-time X2 interface communication during the feedback reception process, thereby resolving the contradiction between decoding accuracy and interface latency.
2Loss of information
If the PCell receives HARQ-ACK feedback from SCell through X2 interface, then inter-cell coordination is maintained, but the high latency leads to uncertainties in resource allocation and decoding
Solution Approach 1:
The invention extracts the critical function of determining HARQ-ACK bit count from the delayed X2 interface communication path and relocates it to the PCell's local processing. The PCell directly determines the number of feedback bits using downlink resource allocation information, removing the time-consuming X2 interface transmission step for this specific information exchange while maintaining the necessary inter-cell coordination.
3Productivity
If carrier aggregation is implemented with multiple cells, then bandwidth and data transmission capacity are improved, but processing data packets through multiple transmission links becomes more complex and challenging
Solution Approach 1:
The invention segments the complex multi-cell HARQ-ACK processing into independent, manageable components. Each cell's downlink resource allocation information is processed separately to determine the corresponding HARQ-ACK bit count, and these individual results are then combined. This segmentation approach simplifies the overall processing complexity while maintaining the high data transmission capacity enabled by carrier aggregation.
Data Source
Figure 1~2
Figure 3A~3B
Figure 4~5
AI summary
Methods and apparatuses in a communication system, are provided. The solution comprises controlling (300) a connection to a user terminal having connections to more than one cell for carrier aggregation, controlling (302) transmission of signalling to the user terminal to use maximum allowable number of bits of hybrid automatic request feedback in transmission of positive and negative acknowledgements to more than one aggregated cell, controlling (304) reception of feedback bits from the user terminal, the feedback bits comprising positive and negative acknowledgements related t0 user terminal connections with the more than one aggregated cell, decoding (306) and processing feedback bits related to the connections controlled by the apparatus and transmitting (308) feedback bits related to other connections to respective cell.