Wireless Transmitter Phase Rotation Sequence for Interference Reduction
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Solution Overview
Problem
Wireless communication technologies face limitations in achieving long-range communication due to interference, which results in a large difference between average and peak power of transmit signals, leading to reduced communication range and quality.
Innovation Solution
The implementation of a wireless transmitter that generates a transmit signal using a phase rotation sequence with a frequency response bandwidth, which is up-sampled and frequency-shifted to ensure high power efficiency and non-overlapping transmission spectra, reducing interference and extending communication range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If binary spreading codes are used for long-range wireless communication, then communication range is extended, but the difference between average power and peak power of transmit signal increases
Solution Approach 1:
The patent changes the fundamental parameter of the spreading code from binary phase shift keying (BPSK) to quadrature phase shift keying (QPSK), transitioning from ±1 values to ±1±j values. This parameter change in the modulation scheme fundamentally alters the power characteristics of the spread signal, reducing the peak-to-average power ratio while maintaining the spreading gain necessary for long-range communication.
2Reliability
If amplifier back-off is increased to inhibit non-linear distortion, then communication quality is maintained, but available transmit power is reduced
Solution Approach 1:
By changing the modulation parameter from binary to quadrature phase shift keying, the patent reduces the peak-to-average power ratio of the transmitted signal. This allows the power amplifier to operate closer to its saturation point without producing significant non-linear distortion, thereby increasing available transmit power while maintaining communication quality.
3Reliability
If spreading factor is increased to reduce noise resistance, then communication range is extended, but transmission rate decreases
Solution Approach 1:
The patent changes the modulation scheme from BPSK to QPSK, which effectively doubles the data rate for the same spreading factor. This parameter change in the modulation order allows the system to maintain higher transmission rates while achieving the same noise resistance and communication range performance.
Data Source
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AI summary
A transmitter includes: a phase rotation sequence generation unit (110) that generates, on the basis of transmit bits being input, a phase rotation sequence in which a frequency response has a bandwidth; an up-sampling unit (111) that changes a sample rate of the phase rotation sequence and further replicates the phase rotation sequence; and a frequency shift unit (112) that shifts, by a specified amount of shift on a frequency axis, a frequency component of the phase rotation sequence acquired from the up-sampling unit (111).