Phase Rotation for Wireless Signal Duplication
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Solution Overview
Problem
Wireless transmission of OFDM and QPSK signals faces challenges due to increased complexity, sensitivity to frequency synchronization issues, high peak-to-average-power ratio (PAPR), and poor power efficiency, particularly when transmitting repeated signals that often touch zero in the time domain, making them difficult to transmit without noise.
Innovation Solution
The solution involves duplicating data strings and phase rotating one copy of the symbols to create distinct signal characteristics, reducing the number of times the signal touches zero in the time domain, thereby improving transmission robustness and power efficiency without adding significant hardware complexity. This is achieved through duplication logic, transformation logic, and signal generation logic that generate signals for wireless transmission using conjugate values and rotated symbols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If OFDM and QPSK signals are transmitted to increase data rate, then data transmission capacity is improved, but hardware complexity increases and power efficiency deteriorates
Solution Approach 1:
The patent transmits two copies of the same data string through different signal paths (one direct, one through conjugation and rotation). This copying approach provides redundancy for error correction while maintaining simpler individual signal structures compared to complex OFDM modulation, thus improving reliability without proportionally increasing hardware complexity
Solution Approach 2:
The patent transforms the signal parameters by converting data strings to conjugate values and rotating symbols based on constellation diagrams. These parameter changes (conjugation, phase rotation) modify the signal characteristics to reduce PAPR and improve power efficiency while maintaining data transmission capacity
2Reliability
If repeated signals are transmitted for error correction, then reliability is improved, but the signal touches zero frequently in time domain making it noise-sensitive
Solution Approach 1:
The patent introduces asymmetry by transmitting one copy of the data string in its original form and another copy after applying conjugation and phase rotation. This asymmetric transformation ensures that the two signal copies have different temporal characteristics, reducing simultaneous zero-crossings and thereby decreasing noise sensitivity while maintaining error correction capability through diversity
3Productivity
If multiple sub-carriers are used in OFDM to maintain data rate, then data transmission efficiency is improved, but sensitivity to frequency synchronization problems increases
Solution Approach 1:
The patent segments the data transmission into two separate paths: one transmitting the original data string and another transmitting transformed copies. This segmentation allows each path to operate with simpler modulation requirements compared to multi-carrier OFDM, reducing sensitivity to frequency synchronization issues while maintaining overall data transmission efficiency through spatial or temporal multiplexing
Data Source
AI summary
Devices, systems, methods, and other embodiments associated with phase based transformation of repeated signals are described. In one embodiment, an apparatus includes duplication logic configured to duplicate a string of data to form a duplicate string of data. Transformation logic is configured to modify phases associated with the string of data to generate a modified string of data. Signal generation logic is configured to generate a signal for wireless transmission where the signal having at least the modified string of data and the duplicate string of data.