Band Limiting Filter for Faster Than Nyquist Transmission

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Solution Overview

Problem

In single-carrier block transmission, Faster than Nyquist transmission techniques increase interference between symbols, leading to higher calculation demands and hardware requirements on the reception side, which hinders the improvement of signal transmission speed.

Innovation Solution

A transmission apparatus that generates N symbols, converts them to a frequency domain signal, applies band limitation to reduce the bandwidth, and then converts back to a time domain signal for transmission, using techniques like DFT and IDFT, while incorporating band limiting filters and CP insertion to manage interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If Faster than Nyquist transmission technique is applied to SC block transmission, then signal transmission speed is improved, but interference between symbols occurs and calculation amount on reception side increases

Engineering Contradiction:
Improvesignal transmission speedVSAvoidcalculation amount on reception side
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The invention performs preliminary band limitation on the frequency domain signal before transmission. By pre-limiting the bandwidth to a second bandwidth narrower than the first bandwidth, the system prepares the signal to reduce inter-symbol interference before it reaches the receiver, thereby enabling faster transmission without proportionally increasing reception complexity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the bandwidth parameter of the transmitted signal by applying band limitation. The frequency domain signal is transformed from having a first bandwidth to having a second bandwidth (narrower than the first), which modifies the signal characteristics to reduce interference while maintaining transmission speed improvements

Inventive Principle:
Principle #35Parameter changes

2Productivity

If Faster than Nyquist transmission technique is applied, then transmission speed is improved, but hardware size on reception apparatus increases

Engineering Contradiction:
Improvetransmission speedVSAvoidhardware size
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The band limiting filter is applied at the transmitter side as a preliminary action to constrain the signal bandwidth before transmission. This pre-processing reduces the complexity of the reception apparatus hardware by ensuring that the incoming signal already has limited bandwidth, reducing the need for complex filtering and processing hardware at the receiver

Inventive Principle:
Principle #10Preliminary action

3Productivity

If band limitation is applied to reduce bandwidth, then transmission efficiency is improved, but signal power may be reduced

Engineering Contradiction:
Improvetransmission efficiencyVSAvoidsignal power
Core Design Contradiction:
ProductivityVSPower

Solution Approach 1:

The invention changes the bandwidth parameter of the signal through band limitation, transforming the frequency domain signal from a first bandwidth to a narrower second bandwidth. This parameter change improves transmission efficiency by reducing bandwidth consumption while the system compensates for potential power loss through the structured filtering process

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3264645B1Transmitting apparatus, receiving apparatus, and communication system
Publication Date: 2019.11.06 MITSUBISHI ELECTRIC CORP
  • EP3264645B1 patent drawingFigure 1
  • EP3264645B1 patent drawingFigure 2
  • EP3264645B1 patent drawingFigure 3~4

AI summary

A transmission apparatus (10) according to the present invention includes a symbol generation unit (1) to generate N symbols, with N being an integer equal to or larger than 2, a time-frequency conversion unit (2) to convert the N symbols to a frequency domain signal having N points, a band limiting filter (3) to perform band limitation on the frequency domain signal having the N points to generate a frequency domain signal having ND points which is less than N, an interpolation-processing and frequency-time conversion unit (4) to convert the frequency domain signal having ND points to a time domain signal, and a transmission unit (6) to transmit the time domain signal at a set transmission interval.