OFDM Phase Vector Rotation for Interference Suppression
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Solution Overview
Problem
In multicarrier communication systems, especially in power line communications, interference between different networks reduces channel capacity and transmission efficiency due to the use of a shared phase vector across networks.
Innovation Solution
A communication apparatus and method that dynamically change the phase vector for each network to prevent interference, using phase vector modification and re-rotation units in transmitters and receivers, respectively, to equalize time waveform levels and prevent significant peak overlapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the same phase vector is used for transmission signals in different networks, then interference between networks is suppressed, but channel capacity and transmission efficiency are reduced
Solution Approach 1:
The patent changes the phase vector parameter for each network to prevent interference. Specifically, each network assigns a unique phase vector to its transmission signals, so that when multiple networks share the same physical medium, their signals do not constructively interfere. This resolves the contradiction by modifying the phase vector parameter from a common value to network-specific values, maintaining reliability through controlled interference patterns while improving transmission efficiency by preventing signal cancellation.
2Productivity
If the phase vector is changed for each network to improve transmission efficiency, then channel capacity increases, but interference suppression between networks is reduced
Solution Approach 1:
The patent systematically changes the phase vector parameter for each network while maintaining controlled interference suppression. By assigning specific phase vectors to different networks and managing the interference patterns that result, the system achieves both improved transmission efficiency and maintained reliability through predictable interference behavior.
3Reliability
If a default phase vector is used when no significant peak is detected, then waveform peak suppression is maintained, but transmission efficiency is limited
Solution Approach 1:
The patent dynamically adjusts the phase vector based on network conditions and requirements. Instead of using a static default phase vector, the system selects and changes phase vectors adaptively to optimize both waveform peak suppression and transmission efficiency. This dynamic approach allows the system to maintain reliability when needed while improving transmission efficiency when conditions permit.
Data Source
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AI summary
The present invention is provided to improve transmission efficiency by preventing interference between different networks during data transmission using a multicarrier communication method. Transmitter 10 includes phase vector setting unit 11 and multicarrier modulator 12. Phase vector setting unit 11 rotates a phase of transmission data corresponding to each subcarrier signal in an OFDM multicarrier signal, by generating a randomized phase vector for each subcarrier signal. Multicarrier modulator 12 modulates the multicarrier signal as transmission data by using an inverse Fourier transform or an inverse wavelet transform. Phase vector setting unit 11 changes a phase vector according to the status of a transmission line or the status of another network.