HARQ-ACK Spatial Bundling in Carrier Aggregation
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Solution Overview
Problem
In wireless communication systems, particularly in LTE and LTE-A, the transmission of HARQ-ACK feedback information across multiple cells in carrier aggregation systems is inefficient due to the lack of standardized methods for determining the number of bits required for HARQ-ACK transmission, leading to suboptimal use of spectral resources and varying transmission modes across different cells.
Innovation Solution
The method involves higher layer signaling to determine whether to apply HARQ-ACK spatial bundling on PUCCH or PUSCH, with specific bit determination based on UL DAI and transmission modes, optimizing DCI formats by introducing UL and DL DAI fields in FDD systems to manage HARQ-ACK bits effectively across multiple cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If HARQ-ACK feedback information is transmitted across multiple cells in carrier aggregation systems without standardized bit determination methods, then the system supports multiple cells and transmission modes, but the spectral resource utilization becomes suboptimal and transmission efficiency decreases
Solution Approach 1:
The patent applies parameter changes by dynamically determining the number of HARQ-ACK bits based on the UL DAI value and transmission mode. The system changes the bit allocation parameters according to the scheduled cell count and MIMO configuration, optimizing spectral resource utilization while maintaining support for multiple cells and transmission modes.
Solution Approach 2:
The patent implements dynamics by making the HARQ-ACK bit determination adaptive rather than static. The bit count dynamically adjusts based on the UL DAI field value received in DCI formats and the actual transmission mode, allowing the system to optimize performance for different carrier aggregation configurations and traffic conditions.
2Productivity
If UL DAI field is introduced in DCI formats for FDD systems to manage HARQ-ACK bits, then bit allocation becomes optimized and spectral resource utilization improves, but the DCI format complexity increases
Solution Approach 1:
The patent applies universality by designing the UL DAI field to serve multiple functions: it indicates the number of scheduled cells, determines HARQ-ACK bit allocation, and works across different DCI formats (0/4 for uplink, 1/2/3/6 for downlink) and transmission modes. This multi-functional approach optimizes spectral resource utilization while avoiding the need for separate signaling mechanisms for each function.
Solution Approach 2:
The patent uses parameter changes by configuring the UL DAI field with different bit widths (1 or 2 bits) depending on the carrier aggregation configuration and transmission mode. This flexible parameter adjustment allows the system to balance between providing sufficient information for HARQ-ACK management and minimizing the overhead added to DCI formats.
Data Source
AI summary
Methods and devices are provided for transmitting and receiving hybrid automatic repeat request acknowledgement (HARQ-ACK) information in a wireless communication system. Higher layer signaling is received that includes at least one of information indicating whether to apply HARQ-ACK spatial bundling to HARQ-ACK information to be transmitted on a physical uplink control channel (PUCCH) or information indicating whether to apply HARQ-ACK spatial bundling to HARQ-ACK information to be transmitted on a physical uplink shared channel (PUSCH). At least one HARQ-ACK information bit corresponding to downlink data received in at least one cell, is determined based on the higher layer signaling. HARQ-ACK information corresponding to the determined at least one HARQ-ACK information bit is transmitted on at least one of the PUCCH or the PUSCH.