Multi-Subframe Precoded Reference Symbols for Channel Estimation
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Solution Overview
Problem
Current wireless communication networks face limitations in radio channel estimation and demodulation performance due to constraints in precoding resource block bundling, which can lead to high signal overhead and reduced accuracy.
Innovation Solution
The method involves assigning resource elements across multiple subframes with static precoding indications, allowing UE-specific reference symbols to be precoded and used for channel estimation across multiple subframes, enhancing processing gain and reducing abrupt precoding changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If precoding resource block bundling is used to maintain static precoding across resource blocks, then channel estimation accuracy is improved, but signal overhead increases and demodulation performance deteriorates
Solution Approach 1:
The patent divides the transmission resource into subframe-level precoding groups rather than resource block-level groups. By extending the precoding bundling scope from individual resource blocks to multiple subframes, the system reduces the number of precoding changes while maintaining adequate channel estimation accuracy. This segmentation at a coarser granularity level reduces signal overhead while preserving the essential benefit of static precoding assumption for channel estimation.
Solution Approach 2:
The patent merges multiple subframes into a single precoding bundling group, allowing the UE to assume static precoding across these combined subframes. This merging approach reduces the frequency of precoding updates and decreases the associated signal overhead for indicating precoding changes, while still providing sufficient channel estimation accuracy through the extended observation window.
2Adaptability or versatility
If precoding changes frequently to adapt to channel conditions, then adaptability is improved, but channel estimation accuracy deteriorates due to abrupt changes
Solution Approach 1:
The patent implements a dynamic precoding strategy where the precoding bundling configuration can be adjusted based on channel conditions and traffic requirements. The system dynamically selects between different bundling granularities (subframe-level or resource block-level) and adapts the precoding update frequency, balancing the trade-off between adaptability to changing channel conditions and maintaining accurate channel estimation.
Solution Approach 2:
The patent changes the temporal parameter of precoding update frequency and the granularity of precoding groups based on system conditions. By adjusting these parameters, the system can reduce precoding change frequency to improve channel estimation accuracy when channels are stable, while maintaining the capability to increase adaptability when channels change rapidly, thus resolving the contradiction between adaptability and estimation accuracy.
3Productivity
If multi-subframe assignment is used to reduce control signaling, then productivity is improved, but device complexity increases
Solution Approach 1:
The patent implements a universal precoding assumption that applies across multiple subframes within a bundling group. The UE uses a single channel estimation derived from reference signals to demodulate data across multiple subframes, making the processing method universally applicable regardless of the number of subframes in the bundle. This multi-functionality approach reduces control signaling overhead while keeping UE processing complexity manageable through standardized estimation and demodulation procedures.
Data Source
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AI summary
For data transmission in a wireless communication network, a radio channel divided into subframes in the time domain is used. A network system (100) assigns resource elements in a first subframe (20) and at least one subsequent subframe (21, 22) to a user equipment (200). By downlink control information transmitted in the first subframe (20), the network system (100) sends a multi-subframe assignment (503) to the user equipment (200). The multi-subframe assignment (503) indicates the assigned resource elements to the user equipment (200). In at least a part of the assigned resource elements in the first subframe (20) and at least a part of the assigned resource elements in the at least one subsequent subframe (21, 22), the network system (100) transmits precoded reference symbols(504, 06, 508) to the user equipment (200). Further, the network system (100) sends an indication (501) to the user equipment (200) that the user equipment (200) is allowed to assume that precoding of the reference symbols(504, 506, 508) is static over the first subframe (20) and the at least one subsequent subframe (20, 21). The user equipment (200) may utilize the precoded reference symbols (504, 506, 508) for channel estimation.