Uplink Precoding Matrix Validity Across Mixed Feedback Conditions
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Solution Overview
Problem
Current uplink precoding frameworks in wireless communications systems face challenges with limited precoder information feedback, leading to suboptimal performance and increased signaling overhead, particularly in scenarios with varying coherence assumptions among antenna ports.
Innovation Solution
Implementing a new uplink transmit precoding matrix framework that combines open-loop and closed-loop precoding techniques, utilizing Space-Frequency Block Coding (SFBC) with SRS and DMRS for improved throughput, and differential TPMI signaling to balance signaling overhead and performance across different sub-bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If closed-loop precoding is used to improve transmission performance, then uplink transmission throughput is improved, but signaling overhead increases due to frequent TPMI updates
Solution Approach 1:
The patent implements dynamic validity periods for TPMI configurations, where each TPMI is associated with a time window (e.g., 4 slots) during which it remains valid without requiring continuous retransmission of the TPMI indicator. This dynamic approach allows the system to adapt to changing channel conditions while reducing signaling overhead by maintaining precoding information temporarily without immediate updates.
Solution Approach 2:
The patent applies preliminary action by configuring TPMI validity periods in advance through higher-layer signaling (RRC configuration), where the network pre-establishes time windows for which each TPMI remains valid. This preliminary configuration eliminates the need for continuous TPMI retransmission during the validity period, reducing signaling overhead while maintaining optimal precoding performance throughout the predetermined time window.
2Reliability
If frequent TPMI updates are performed to adapt to channel changes, then transmission performance is optimized, but signaling overhead increases
Solution Approach 1:
The system dynamically manages TPMI validity periods based on channel conditions and network requirements. Each TPMI configuration is associated with a time window (e.g., 4 slots) during which it remains valid, allowing the system to balance between adapting to channel changes and reducing signaling overhead. The network can extend or shorten validity periods based on actual channel stability.
Solution Approach 2:
The patent implements feedback mechanisms where the UE monitors channel conditions and can request TPMI updates when necessary, while the network also provides feedback through validity period management. This feedback loop allows the system to maintain optimal transmission performance by updating TPMI only when channel conditions change significantly, rather than following a fixed update schedule that would waste signaling resources.
3Loss of information
If TPMI is valid for multiple time slots to reduce signaling, then signaling overhead is reduced, but adaptability to channel changes decreases
Solution Approach 1:
The patent implements dynamic validity periods for TPMI configurations, where each TPMI is associated with a time window (e.g., 4 slots) during which it remains valid without requiring continuous retransmission of the TPMI indicator. This dynamic approach allows the system to adapt to changing channel conditions while reducing signaling overhead by maintaining precoding information temporarily without immediate updates.
Solution Approach 2:
The system changes the parameter of TPMI validity duration based on channel conditions and network requirements. The network can configure different validity periods (e.g., 2, 4, or 8 slots) depending on channel stability and mobility conditions. This parameter adjustment allows the system to balance between reducing signaling overhead and maintaining adaptability to channel changes.
Data Source
AI summary
Various aspects of the present disclosure relate to a User Equipment (UE) configured to or operable to receive a configuration associated with a Sounding Reference Signal (SRS), transmit a set of SRSs based on the SRS configuration in a first time slot, receive a first uplink (UL) codebook configuration comprising one or more parameters including at least a transmit precoding matrix indicator (TPMI) that is valid for UL codebook-based transmissions for a plurality of time slots, transmit a signal over a physical uplink shared channel (PUSCH) in a first time slot using the TPMI, and transmit additional signals in respective additional time slots after the first time slot while the TPMI is valid.