Transmission Power Control via Waterfilling Algorithm
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Solution Overview
Problem
In digital communication systems like DSL, the transmission range decreases with increasing bit rate due to attenuation and crosstalk issues, particularly in systems with multiple transmission lines where excessive power on one line can disturb others.
Innovation Solution
A method of transmission power control using an optimization algorithm to adjust the transmission power spectral density of each channel, maximizing the total bit rate while considering signal-to-noise ratio and interference, and assigning relative bit rates to balance power distribution across channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If transmission power is increased to achieve higher bit rates, then data transmission rate is improved, but crosstalk interference on other transmission lines increases
Solution Approach 1:
The patent applies local quality by adjusting the transmission power spectral density individually for each frequency subchannel based on its specific channel conditions. The waterfilling algorithm allocates more power to subchannels with better signal-to-noise ratio and less to those with poorer conditions, optimizing each subchannel's contribution to the total bit rate while minimizing overall interference.
Solution Approach 2:
The patent changes the transmission power parameter dynamically by applying the waterfilling algorithm, which redistributes power across frequency subchannels based on channel state information. This parameter optimization allows the system to achieve higher bit rates by concentrating power in frequency regions with lower attenuation and interference, rather than using uniform power allocation.
2Productivity
If transmission power spectral density is optimized for one transmission channel, then bit rate of that channel is improved, but interference to other transmission channels increases
Solution Approach 1:
The patent merges the optimization of multiple transmission channels by considering all channels simultaneously in the waterfilling algorithm. The algorithm takes into account the channel state information of all channels and performs joint power allocation, ensuring that power distribution in one channel does not excessively interfere with others. This combined optimization approach balances the bit rates across all channels while minimizing mutual interference.
3Productivity
If broad frequency band is used for high bit rate transmission, then data rate is improved, but transmission range decreases due to attenuation
Solution Approach 1:
The patent transitions from a single-dimensional approach (uniform power across all frequencies) to a multi-dimensional approach by allocating power differently across the frequency dimension. The waterfilling algorithm identifies frequency subchannels with better propagation characteristics and concentrates power in those regions, effectively extending the usable frequency band for long-distance transmission while maintaining high bit rates.
Data Source
AI summary
In a method of transmission power control, transmission powers of transmission channels and/or transmission power spectral densities are adjusted so as to improve the transmission characteristics.