Adaptive Symbol Interval Adjustment for FTN Communication
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Solution Overview
Problem
Faster-than-Nyquist (FTN) modulation schemes face challenges due to inter-symbol interference, which increases the load on reception apparatuses and deteriorates communication quality, especially in varying communication environments.
Innovation Solution
An apparatus and method that adaptively adjust symbol or subcarrier intervals based on the communication environment, using a compression coefficient to balance processing load and frequency use efficiency by adjusting the compression coefficient according to channel frequency and component carrier types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If FTN modulation is applied to narrow symbol intervals beyond Nyquist conditions, then frequency use efficiency is improved, but inter-symbol interference increases and reception apparatus load increases
Solution Approach 1:
The patent applies dynamics by making the symbol interval adaptive rather than fixed. The base station dynamically adjusts the symbol interval based on communication environment conditions (such as channel state, interference level, and reception apparatus capability), allowing the system to transition between Nyquist and FTN modulation modes as needed, thereby resolving the contradiction between maintaining high frequency efficiency and managing reception complexity
Solution Approach 2:
The patent changes the symbol interval parameter adaptively. By modifying the symbol interval from a fixed Nyquist-compliant value to a variable parameter that can be adjusted based on communication conditions, the system can optimize frequency use efficiency while controlling inter-symbol interference and reception apparatus load through parameter adaptation
2Productivity
If symbol intervals are narrowed beyond Nyquist conditions, then frequency use efficiency is improved, but communication quality deteriorates due to inter-symbol interference
Solution Approach 1:
The patent makes the symbol interval dynamic, allowing the system to adapt between narrow intervals (for high frequency efficiency) and wider intervals (for high communication quality) based on real-time communication conditions, thereby resolving the contradiction between frequency efficiency and communication quality
Solution Approach 2:
The patent changes the symbol interval parameter based on communication environment assessment. When conditions favor FTN modulation, the parameter is adjusted to narrower intervals for efficiency; when interference becomes problematic, the parameter returns to Nyquist-compliant intervals for quality, thus resolving the contradiction through parameter adaptation
3Adaptability or versatility
If adaptive adjustment of symbol intervals is implemented, then adaptability to different communication environments is improved, but system complexity increases
Solution Approach 1:
The patent segments the communication system into distinct functional blocks: an environment assessment unit that evaluates communication conditions, a decision unit that determines appropriate symbol intervals, and a modulation unit that implements the selected interval. This segmentation allows adaptive functionality to be added modularly, improving adaptability while managing system complexity through structured organization
Solution Approach 2:
The patent implements feedback mechanisms where the reception apparatus provides information about communication quality and channel conditions back to the base station. The base station uses this feedback to adjust symbol intervals adaptively, achieving environment-specific optimization without requiring overly complex open-loop processing at the reception side
Data Source
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AI summary
[Object] To adaptively adjust a symbol interval or a subcarrier interval in accordance with a communication environment. [Solution] There is provided an apparatus including: a communication unit configured to perform radio communication; and a control unit configured to perform control such that transmission is performed from the communication unit to a terminal by narrowing at least one of a symbol interval of a complex symbol sequence in a time direction and a subcarrier interval of the complex symbol sequence in a frequency direction, the complex symbol sequence being converted from a bit sequence, the symbol interval and the subcarrier interval being set on a basis of a predetermined condition.