Temporal Domain Precoding for Wireless PAPR Reduction
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Solution Overview
Problem
Current wireless communication systems face challenges in effectively reducing the peak to average power ratio (PAPR) of downlink signals, particularly due to the Doppler frequency domain, which is not adequately addressed by existing precoding techniques that only consider frequency and spatial domains.
Innovation Solution
The system configures user equipment (UE) to report parameters in the temporal domain to the base station, allowing for the selection of Doppler frequency bins and determination of discrete Fourier transform (DFT) vectors, enabling Doppler frequency domain compression and further reducing PAPR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If precoding operation is performed based on existing techniques considering only frequency and spatial domains, then PAPR reduction is partially achieved, but PAPR reduction is insufficient due to not addressing the Doppler frequency domain
Solution Approach 1:
The patent extends precoding from traditional frequency and spatial domains to include the temporal (Doppler) domain, adding a new dimension to the precoding operation. This is achieved by determining DFT vectors in the temporal domain and applying temporal domain precoding matrices, thereby comprehensively addressing PAPR reduction across multiple domains including the previously neglected Doppler frequency domain
Solution Approach 2:
The patent changes the parameters considered in precoding by introducing temporal domain parameters (Doppler frequency, DFT vectors in temporal domain) alongside traditional frequency and spatial parameters. This parameter expansion allows the system to adapt precoding to channel conditions across all three domains, improving overall PAPR reduction effectiveness
2Loss of energy
If the system configures UE to report temporal domain parameters and perform Doppler frequency domain compression, then PAPR reduction is enhanced, but device complexity and processing requirements increase
Solution Approach 1:
The patent performs preliminary actions by having the UE estimate channel conditions in the temporal domain and determine DFT vectors before actual data transmission. The base station pre-calculates temporal domain precoding matrices based on reported parameters, preparing precoding factors in advance to reduce PAPR without adding real-time processing complexity during transmission
Solution Approach 2:
The patent introduces DFT vectors in the temporal domain as intermediaries between the channel state information and the precoding operation. These DFT vectors serve as a bridge that transforms channel characteristics into appropriate precoding matrices, simplifying the overall processing by providing a structured intermediate representation that facilitates Doppler frequency domain compression
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. The method may include a first network node receiving a configuration message for a report by the first network node of parameters for a temporal domain precoder. The configuration message may indicate a range of Doppler frequencies, a resolution associated with the range of Doppler frequencies, or a quantity of the parameters to be reported. The first network node may estimate a communications channel and select one or more bins within the range of Doppler frequencies based on the channel estimation. For each selected bin, the first network node may determine a corresponding discrete Fourier transform (DFT) vector and transmit a report indicating the corresponding DFT vector.