UL MIMO HARQ-ACK Resource Element Allocation
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Solution Overview
Problem
Current multiplexing methods for control and data signals in uplink MIMO systems, particularly in LTE and LTE-A standards, face limitations in efficiently handling multiple codewords and resource allocation for HARQ-ACK and RI feedback, leading to reliability issues due to zero minimum distance errors in channel coding.
Innovation Solution
The proposed method enhances multiplexing by determining a minimum number of resource elements (REs) for HARQ-ACK and RI feedback, ensuring reliable decoding through specific equations and channel coding techniques, such as Reed-Muller codes, and optimizing resource allocation based on payload and modulation schemes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional multiplexing methods are used in uplink MIMO systems, then resource allocation is simplified, but reliability deteriorates due to zero minimum distance errors in channel coding
Solution Approach 1:
The patent segments the control information (HARQ-ACK and RI) into separate coding processes. Different channel coding schemes are applied to different control information types, with specific attention to ensuring non-zero minimum distance for each segment. This segmentation allows tailored error protection for each control information type, improving overall reliability without applying complex schemes uniformly across all control signals.
Solution Approach 2:
The patent changes the channel coding parameters specifically for control information in uplink MIMO systems. By adjusting the code rate, block length, and minimum distance parameters of the channel coding scheme, the patent ensures that control information achieves sufficient error protection. This parameter optimization resolves the reliability issue without requiring fundamentally new coding structures.
2Reliability
If minimum number of REs is guaranteed for control information, then reliability improves, but resource allocation complexity increases
Solution Approach 1:
The patent performs preliminary determination of the minimum number of resource elements required for control information before actual resource allocation. By calculating and reserving the minimum REs needed for reliable decoding in advance, the patent simplifies the subsequent resource allocation process. This preliminary action ensures that control information always receives sufficient resources without requiring complex real-time adjustments during scheduling.
3Productivity
If multiple codewords are supported in UL MIMO, then data transmission capacity increases, but control and data multiplexing becomes more complex
Solution Approach 1:
The patent segments control information and data into separate processing streams with distinct channel coding schemes. By treating control information (HARQ-ACK, RI) and data codewords independently with appropriate coding parameters, the patent manages the complexity of multiplexing multiple codewords while ensuring reliable control information transmission. This segmentation approach allows scalable support for multiple codewords without proportionally increasing control multiplexing complexity.
Data Source
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AI summary
In a wireless network that operates according to the Long-Term Evolution Advanced standard, a mobile station determines a number of resource elements to be used for HARQ-ACK (hybrid automatic-repeat-request acknowledgement information) or RI (rank indication) on a MIMO (multiple-input multiple-output) PUSCH (physical uplink shared channel). In an embodiment, the mobile station determines a number O of bits in a payload for HARQ-ACK or RI. When the payload O is within a first range, the mobile station determines a minimum number Qmin of resource elements to be used according to a first equation. When the payload O is within a second range, the mobile station determines the minimum number Qmin of resource elements to be used according to a second equation. The mobile station then determines the number Q' of resource elements according to Qmin and a third equation.