PUCCH Transmission Switching for Low SNR Demodulation
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Solution Overview
Problem
Current wireless communication systems, particularly in 5G NR and LTE, face performance degradation at low signal-to-noise ratio (SNR) conditions due to the use of coherent PUCCH transmissions with demodulation reference signals (DMRS), which can be suboptimal and limit channel estimation quality.
Innovation Solution
The system allows for dynamic switching between coherent and non-coherent PUCCH transmissions, enabling adaptation to low SNR conditions by using non-coherent transmissions without DMRS, thereby improving demodulation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If coherent PUCCH transmissions with DMRS are used, then channel estimation quality is improved under normal conditions, but performance degrades at low SNR conditions due to energy wasted on DMRS
Solution Approach 1:
The system dynamically switches between coherent and non-coherent PUCCH transmission modes based on real-time SNR conditions. The network entity signals the UE to use non-coherent transmission when low SNR is detected, allowing adaptive adjustment of transmission parameters to optimize performance under varying channel conditions
Solution Approach 2:
The patent changes the transmission parameter from coherent to non-coherent mode by modifying the PUCCH format configuration. This involves changing the modulation scheme and removing DMRS from the transmission, thereby adapting the system parameters to low SNR conditions to reduce energy waste while maintaining acceptable demodulation performance
2Reliability
If coherent PUCCH transmissions are used, then demodulation performance is improved under good channel conditions, but reliability decreases at low SNR conditions
Solution Approach 1:
The network entity provides feedback signaling to the UE about the appropriate PUCCH transmission mode based on channel conditions. This feedback mechanism allows the system to adjust transmission parameters dynamically, switching to non-coherent mode when low SNR conditions reduce the reliability of coherent transmission
Solution Approach 2:
The system implements dynamic adaptation by switching between coherent and non-coherent transmission modes based on real-time SNR measurements. This dynamic adjustment optimizes the balance between demodulation performance and energy efficiency under varying channel conditions
3Loss of energy
If non-coherent PUCCH transmissions without DMRS are used, then energy efficiency is improved at low SNR, but channel estimation capability is reduced
Solution Approach 1:
The system changes the transmission parameters by switching to non-coherent mode, which removes DMRS from the transmission. This parameter change optimizes energy efficiency at low SNR by eliminating unnecessary DMRS energy, accepting reduced channel estimation capability as a trade-off for significant energy savings and improved demodulation performance
Data Source
AI summary
Aspects of the present disclosure provide apparatus, methods, processing systems, and computer readable mediums that allow a switch between coherent physical uplink control channel (PUCCH) transmissions (e.g., that include demodulated reference signals (DMRS)) and non-coherent PUCCH transmissions (e.g., without DMRS). An example method by a user equipment (UE) generally includes receiving, from a network entity, a configuration of a set of PUCCH resources with different PUCCH formats, receiving signaling, from the network entity, indicating one of the PUCCH resources for a PUCCH transmission and whether the PUCCH transmission is to be sent as a coherent transmission or non-coherent transmission, and sending the coherent or non-coherent PUCCH transmission in accordance with the indication.