Uplink Waveform Switching via L1 Signaling in NR
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Solution Overview
Problem
Current wireless communication networks face inefficiencies in uplink transmission due to complex switching between CP-OFDM and DFT-S-OFDM waveforms, leading to resource underutilization and performance degradation, especially in rapidly changing channel conditions.
Innovation Solution
Implementing a mechanism for dynamic switching between DFT-S-OFDM and CP-OFDM waveforms using Layer 1 signaling to optimize power usage, with a base station and user equipment configuring bandwidth parts to reduce unnecessary waveform changes and transition times, thereby minimizing performance degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If dynamic switching between CP-OFDM and DFT-S-OFDM waveforms is implemented to optimize power usage and adapt to channel conditions, then power efficiency and data rate are improved, but system complexity increases due to RRC configuration and DCI format changes
Solution Approach 1:
The patent implements dynamic waveform switching between CP-OFDM and DFT-S-OFDM based on real-time channel conditions and UE capabilities. The system adapts the waveform type dynamically through RRC configuration and DCI format selection, allowing optimal power efficiency and data rate performance while managing complexity through structured configuration procedures
Solution Approach 2:
The patent changes the waveform parameter (CP-OFDM vs DFT-S-OFDM) based on channel conditions, UE power constraints, and traffic requirements. This parameter adaptation enables the system to optimize power efficiency by selecting DFT-S-OFDM for power-constrained scenarios and CP-OFDM for high-data-rate scenarios, while managing complexity through standardized configuration mechanisms
2Use of energy by moving object
If RRC reconfiguration is used to optimize power usage by switching waveforms, then power efficiency improves, but service disruption occurs due to 30-40 msec reconfiguration time during which UE cannot transmit or receive
Solution Approach 1:
The patent performs preliminary RRC configuration of multiple waveform options and DCI format mappings before service disruption occurs. By pre-configuring the UE with multiple waveform capabilities and associated DCI formats, the system enables faster waveform switching without requiring lengthy reconfiguration procedures during active transmission, thus reducing service disruption time while maintaining power efficiency benefits
3Use of energy by moving object
If DFT-S-OFDM is used for UL transmission to reduce PAPR and power consumption, then power efficiency improves, but flexibility is reduced due to single transmission layer limitation and contiguous frequency allocation requirement
Solution Approach 1:
The patent makes the UL transmission system universal by supporting both DFT-S-OFDM and CP-OFDM waveforms, each serving different functional requirements. DFT-S-OFDM provides power-efficient single-layer transmission for coverage-limited scenarios, while CP-OFDM enables multi-layer transmission and non-contiguous frequency allocation for high-data-rate scenarios. The system selectively applies the appropriate waveform based on channel conditions and traffic requirements
Solution Approach 2:
The patent dynamically selects between DFT-S-OFDM and CP-OFDM based on real-time channel conditions, UE power constraints, and traffic characteristics. This dynamic adaptation allows the system to optimize power consumption by using DFT-S-OFDM when appropriate while maintaining scheduling flexibility through CP-OFDM when multi-layer or non-contiguous allocation is required
4Productivity
If CP-OFDM is used to support multiple transmission layers for higher data rates, then data rate improves, but power efficiency deteriorates due to higher PAPR
Solution Approach 1:
The patent changes the waveform parameter between CP-OFDM and DFT-S-OFDM based on the trade-off between data rate requirements and power efficiency constraints. CP-OFDM is selected when high data rates are prioritized and power constraints are not severe, while DFT-S-OFDM is selected when power efficiency is critical. This parameter adaptation enables optimal balance between productivity and energy usage
Data Source
AI summary
Methods and apparatus are provided for switching a waveform for UL transmissions in a communication network to optimize power usage of the UE. In exemplary embodiments, the UE can use either CP-OFDM waveform or DFT-S-OFDM waveform for UL transmissions. A mechanism is provided to prevent excessive switching in environments where the channel conditions are rapidly changing. Further, a signaling mechanism is provided for switching waveforms for UL transmissions using Layer 1 (L1) signaling to reduce the transmission time needed to switch between CP-OFDM and DFT-S-OFDM waveforms.