Quadrature Layered Modulation for High-Speed Data Transmission
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Solution Overview
Problem
Current communication technologies face limitations in increasing data symbol rates beyond the Nyquist rate without significant loss in signal strength, particularly in achieving data rates higher than 25% above the Nyquist rate, and there is a need for methods that can support higher data transmission rates while maintaining error rate performance.
Innovation Solution
Quadrature Layered Modulation (QLM) is introduced, which scales signal strength to compensate for inter-symbol interference and allows for increased data symbol rates by layering communications over the same link, using a discriminating parameter for separation and decoding, and employing maximum likelihood and trellis demodulation algorithms to achieve error rate performance comparable to original links.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If data symbol rate is increased above the Nyquist rate, then data transmission rate is improved, but signal strength and error rate performance deteriorate
Solution Approach 1:
The patent segments the data transmission into multiple independent layers, each operating at the Nyquist rate. By dividing the total data rate into np separate layers that can be transmitted simultaneously without interference, the system achieves higher overall data rates while maintaining reliable signal strength and error rate performance for each individual layer.
Solution Approach 2:
The invention introduces a temporal dimension by layering multiple data streams at different time offsets. Instead of increasing the symbol rate within a single dimension, the system adds a temporal dimension with np layers having offsets of 0, 1/np, 2/np, ..., (np-1)/np, enabling simultaneous transmission without intersymbol interference.
2Productivity
If data symbol rate is increased to more than 25% above the Nyquist rate, then data transmission rate is improved, but signal strength loss increases rapidly
Solution Approach 1:
The patent segments the high-rate transmission into multiple lower-rate layers, each operating at the Nyquist rate. This segmentation prevents rapid signal strength loss by ensuring that each layer maintains optimal signal levels, while the combined capacity of all layers achieves the desired high data transmission rate.
3Productivity
If multiple data layers are transmitted simultaneously, then data transmission rate is improved, but inter-symbol interference increases
Solution Approach 1:
The invention resolves the interference problem by introducing temporal separation through different time offsets for each layer. The offsets of 0, 1/np, 2/np, ..., (np-1)/np ensure that symbols from different layers do not overlap in time, eliminating intersymbol interference while allowing simultaneous transmission of multiple layers.
Solution Approach 2:
The patent uses time offsets as an intermediary mechanism to separate multiple data layers. These offsets act as mediators that prevent direct interference between layers while still allowing them to transmit simultaneously, effectively isolating each layer's symbols in the time domain.
Data Source
AI summary
This invention discloses a method for communications faster than the Nyquist rate (FTN) and faster than the Shannon rate which method is Quadrature Layered Modulation (QLM). QLM properties include scaling the data symbol pulses to maintain the same error rate performance for all rates. QLM alternatively considers the increase in the data symbol rate to be a layering of additional communications over the same link. The Shannon bound is a limit on the capacity of a communication link when transmitting data symbols at the Nyquist rate. QLM observes one can communicate at FTN to transmit more information than the Shannon rate since the Nyquist rate captures the information in a frequency band and does not constraint the information. These properties describe QLM and a separate math proof-of-concept is disclosed. Implementation and performance data demonstrate QLM can support communications data rates which are at least double the Shannon rate.