HARQ-ACK Transmission via Downlink Assignment Index in Carrier Aggregation
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Solution Overview
Problem
In wireless communication systems, the transmission of HARQ-ACK information is inefficient due to the lack of proper understanding between User Equipment (UE) and NodeB regarding the HARQ-ACK payload and multiplexing, leading to throughput loss and increased power consumption, especially in Carrier Aggregation scenarios.
Innovation Solution
The implementation of a cell-domain DL DAI IE in DL SAs and a cell-domain UL DAI IE in UL SAs, along with absolute counter, forward relative counter, and bit-map designs, to accurately determine the HARQ-ACK payload and transmission power in PUSCH and PUCCH, ensuring proper functionality and minimizing overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ-ACK information is transmitted without proper payload determination and multiplexing understanding, then transmission simplicity is maintained, but throughput loss occurs and transmission reliability deteriorates
Solution Approach 1:
The patent segments the HARQ-ACK information transmission by introducing separate Downlink Assignment Index (DAI) fields in DCI formats. The DAI is divided into counter DAI and total DAI components, allowing the UE to separately track and determine the HARQ-ACK payload size for each downlink transmission, thereby resolving the ambiguity between transmission simplicity and reliable payload determination.
Solution Approach 2:
The patent implements a feedback mechanism where the DAI information is explicitly fed back from the NodeB to the UE through DCI signaling. This feedback allows the UE to accurately determine the HARQ-ACK payload size and multiplexing configuration, ensuring both transmission reliability and efficient throughput by eliminating guesswork and retransmissions.
2Reliability
If HARQ-ACK payload is not accurately determined, then transmission overhead is reduced, but transmission reliability and power efficiency worsen
Solution Approach 1:
The patent applies preliminary action by having the NodeB pre-configure the DAI information in the DCI before the actual data transmission. This allows the UE to determine the HARQ-ACK payload size in advance, avoiding the need for multiple transmission attempts and reducing power consumption while ensuring reliable transmission.
Solution Approach 2:
The patent changes the parameter structure of the DCI by introducing DAI fields that dynamically indicate the HARQ-ACK payload size. This parameter change allows the system to adapt the transmission configuration to actual needs, reducing unnecessary power consumption while maintaining high reliability through accurate payload determination.
3Productivity
If DTX information is not provided to the NodeB, then UE transmission complexity is reduced, but NodeB cannot use Incremental Redundancy leading to throughput loss
Solution Approach 1:
The patent makes the DAI mechanism universal by designing it to serve multiple functions: it determines HARQ-ACK payload size, indicates DTX conditions, and enables Incremental Redundancy at the NodeB. This multi-functionality allows the UE to provide comprehensive feedback without increasing transmission complexity, thereby improving throughput through efficient HARQ processes.
4Object-generated harmful factors
If PUCCH transmission power is not optimized based on received TBs, then power control simplicity is maintained, but interference increases and power efficiency deteriorates
Solution Approach 1:
The patent introduces dynamic power control for PUCCH transmission by linking the transmission power to the actual number of received transport blocks indicated by the DAI. This dynamic adjustment allows the system to optimize power usage and reduce interference based on actual transmission conditions, while the automated nature of the DAI-based control maintains operational simplicity.
Data Source
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AI summary
Methods and apparatus are described for a User Equipment (UE) to transmit acknowledgement information together with data information in a Physical Uplink Shared CHannel (PUSCH) or separate from data information in a Physical Uplink Control CHannel (PUCCH). The HARQ-ACK payload for transmission in a PUSCH and the HARQ-ACK signal transmission power for transmission in a PUCCH are derived based on the existence and design of a Downlink Assignment Index (DAI) Information Element (IE) in the Downlink Control Information (DCI) formats scheduling receptions of data Transport Blocks (TBs) by the UE.