Multiple DFT Waveforms for PDCCH Multiplexing at High Frequencies
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Solution Overview
Problem
CP-OFDM performance degrades at high frequencies due to sensitivity to phase noise and high peak-to-average power ratio (PAPR) and cubic metric (CM), limiting cell coverage and increasing UE power consumption, while DFT-s-OFDM faces challenges in multiplexing for physical downlink control channels.
Innovation Solution
Implement multiple discrete Fourier transforms (DFTs) for transmission and reception, including configurations for DFT-based waveforms, inverse-DFT (IDFT) configurations, and mapping patterns to enhance PDCCH transmission/reception with DFT-s-OFDM, addressing multiplexing issues of control resource sets, demodulation reference signals, and other channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If CP-OFDM is used for transmission, then high data rate and spectral efficiency are achieved, but performance degrades at high frequencies due to sensitivity to phase noise and high PAPR
Solution Approach 1:
The patent segments the single-carrier DFT-s-OFDM approach into multiple parallel DFT streams. Instead of using a single carrier with high PAPR, the invention divides the transmission into multiple lower-PAPR streams that are combined at the receiver, thereby reducing the peak-to-average power ratio while maintaining spectral efficiency and improving performance at high frequencies.
Solution Approach 2:
The patent changes the fundamental parameter of the waveform from CP-OFDM to multiple DFT-s-OFDM streams. This parameter change transforms the signal characteristics to have lower PAPR and reduced sensitivity to phase noise, enabling reliable high-frequency transmission while maintaining energy efficiency.
2Reliability
If DFT-s-OFDM is used for transmission, then PAPR is reduced and phase noise robustness is improved, but challenges arise in multiplexing for physical downlink control channels
Solution Approach 1:
The patent applies segmentation by dividing the control channel resources into multiple separate DFT streams. Each stream can be independently configured and multiplexed, simplifying the overall multiplexing process while maintaining phase noise robustness. The multiple streams allow for flexible resource allocation and reduce the complexity of managing control channels within a single carrier framework.
Data Source
AI summary
Apparatuses, methods, and systems are disclosed for multiple discrete Fourier transforms for transmission and reception. An apparatus includes a transceiver that receives a first configuration from a network to apply multiple discrete Fourier transform (“DFT”)-based waveforms at one or more of a transmitter and a receiver, receives a second configuration from the network for a physical channel, the second configuration comprising DFT configuration information, and receives a third configuration from the network for determining, based on the second configuration, an inverse-DFT (“IDFT”) configuration. An apparatus includes a processor that performs multiple DFT-based transmissions on a time-domain symbol transmitted to the network based on the first and second configurations and performs multiple IDFT-based receptions of a time-domain symbol received from the network, based on the IDFT configuration.