DCI Tone Reservation for Lower PAPR in UE Transmissions
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Solution Overview
Problem
Wireless communications systems face challenges with high peak-to-average power ratio (PAPR) leading to signal distortions and reduced transmission reliability due to clipping, which affects devices like UEs in LTE and 5G networks.
Innovation Solution
Implementing tone reservation techniques using dynamic tone allocation via DCI to reduce PAPR by reserving spare tones for peak-cancellation signals, dynamically adjusting based on UE-specific factors such as distance and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tone reservation techniques are implemented to reduce PAPR, then transmission reliability is improved, but device complexity increases due to dynamic tone allocation via DCI
Solution Approach 1:
The system performs preliminary action by pre-allocating and reserving specific tones for peak cancellation purposes before data transmission occurs. The base station configures tone reservation parameters and spares tone indicators in advance, allowing the UE to prepare peak cancellation signals without real-time computation, thus improving reliability while managing complexity.
Solution Approach 2:
The patent introduces DCI (Downlink Control Information) as an intermediary mechanism that carries tone allocation information from the base station to the UE. This intermediary structure simplifies the complexity by providing a standardized control channel for tone reservation management, rather than requiring complex direct negotiation or real-time signal processing between devices.
2Reliability
If spare tones are reserved for peak-cancellation signals, then PAPR is reduced, but available bandwidth for data transmission decreases
Solution Approach 1:
The system implements dynamic tone allocation where the base station can adjust the number and position of spare tones based on channel conditions, traffic load, and PAPR requirements. The DCI dynamically indicates which tones are reserved, allowing the system to optimize the balance between PAPR reduction and bandwidth utilization in real-time rather than using fixed reservations.
Solution Approach 2:
The patent changes the parameter of tone allocation from static to dynamic by introducing DCI-based control. The base station can modify tone reservation parameters (number of spare tones, their positions, and allocation patterns) based on system conditions, allowing flexible adjustment of the trade-off between PAPR reduction effectiveness and available data transmission bandwidth.
3Use of energy by moving object
If dynamic tone allocation is used to optimize PAPR reduction, then power consumption is reduced, but signaling overhead increases due to DCI messages
Solution Approach 1:
The DCI structure is designed with multi-functionality, serving both as scheduling control information and as tone reservation allocation information. By combining multiple functions into a single control message format, the patent reduces redundant signaling while maintaining dynamic tone allocation capabilities, thus minimizing overhead while achieving power optimization through adaptive tone management.
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AI summary
Methods, systems, and devices for wireless communications are described. To reduce peak-to-average power ratio (PAPR) associated with transmissions in a wireless communications system, a user equipment (UE) may implement tone reservation techniques. The UE may receive downlink control information from a base station that indicates a set of allocated resources that the UE is to use for the tone reservation. The UE may identify a first set of tones of the set of allocated resources for transmitting a data signal and a second set of tones of the set of allocated resources for transmitting a peak-reduction signal that reduces the peak power of the data signal. The UE may transmit the data signal and the peak-reduction signal based on the received downlink control information.