FTN DFT-s-OFDM Cyclic Prefix Control for High-Band Interference
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The increase of phase noise and propagation loss in high frequency bands beyond 52.6 GHz, along with sensitivity to peak-to-average power ratio (PAPR) and nonlinearity of power amplifiers, poses challenges for efficient radio communication.
Innovation Solution
A terminal that incorporates Faster-Than-Nyquist (FTN) transmission combined with Discrete Fourier Transform-Spread Orthogonal Frequency Division Multiplexing (DFT-s-OFDM), with a control unit to set an appropriate cyclic prefix (CP) based on the time-domain compression rate, and a compression factor (α) to manage inter-symbol and inter-subcarrier interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If FTN transmission is applied to improve frequency utilization efficiency, then spectral efficiency increases, but inter-symbol interference and inter-subcarrier interference occur
Solution Approach 1:
The patent applies FTN transmission which intentionally introduces controlled inter-symbol interference and inter-subcarrier interference to achieve higher spectral efficiency. The system converts these harmful interference effects into a beneficial mechanism by using compression factors less than 1 to multiply the number of transmittable symbols, thereby improving frequency utilization efficiency while managing interference through appropriate parameter selection
Solution Approach 2:
The patent changes the time-domain compression rate parameter (compression factor α < 1) to enable FTN transmission. By adjusting this parameter, the system achieves higher symbol density in the time domain, which directly improves frequency utilization efficiency while the compression factor itself serves as a control mechanism to manage the resulting interference levels
2Device complexity
If a fixed cyclic prefix length is used in FTN transmission, then implementation is simplified, but the relationship between compression rate and CP length may not be appropriate
Solution Approach 1:
The patent implements dynamic adjustment of the cyclic prefix length based on the time-domain compression rate. The control unit sets the CP length according to the compression factor α, creating a dynamic relationship where CP length varies with the compression rate. This ensures appropriate interference cancellation for each compression level while maintaining optimized frequency utilization efficiency
Solution Approach 2:
The system uses feedback control where the control unit determines the CP length based on the selected compression factor. The relationship between compression rate and CP length is dynamically adjusted through control signaling, allowing the system to optimize performance by adapting CP length to the actual compression rate being used in FTN transmission
3Quantity of substance
If high frequency bands beyond 52.6 GHz are used to increase bandwidth, then capacity increases, but phase noise and propagation loss increase
Solution Approach 1:
The patent extracts and removes the harmful effects of phase noise and propagation loss by combining FTN transmission with DFT-s-OFDM. The DFT-s-OFDM structure processes the high-frequency signals through discrete Fourier transform spreading, which separates and manages the interference components, effectively taking out the harmful phase noise and propagation loss effects from the overall signal transmission
Solution Approach 2:
The patent creates a composite transmission scheme by combining FTN time-domain compression with DFT-s-OFDM frequency-domain processing. This composite approach leverages the strengths of both techniques: FTN provides time-domain symbol multiplication while DFT-s-OFDM provides frequency-domain orthogonality and interference management, together enabling effective high-frequency band utilization despite phase noise and propagation loss
4Object-generated harmful factors
If FTN combined with DFT-s-OFDM is used to reduce PAPR, then power amplifier linearity requirements decrease, but system complexity increases
Solution Approach 1:
The patent merges FTN time-domain compression with DFT-s-OFDM frequency-domain spreading into a unified transmission scheme. This combination allows the system to achieve PAPR reduction through the DFT-s-OFDM structure while simultaneously benefiting from the spectral efficiency of FTN, effectively merging two techniques to solve multiple problems at once
Solution Approach 2:
The combined FTN-DFT-s-OFDM system performs multiple functions simultaneously: it achieves time-domain symbol multiplication for spectral efficiency, frequency-domain orthogonality for interference management, and PAPR reduction for relaxed power amplifier requirements. This multi-functional approach allows a single system design to address frequency utilization, interference cancellation, and power amplifier linearity issues together
Data Source
AI summary
A communication device is disclosed that includes a transmission unit that transmits a signal by adding a cyclic prefix to a symbol and a control unit that sets a length of the cyclic prefix longer when the symbol is compressed in a time domain. In other aspects, a communication method is also disclosed.