Frequency-Division Multiplexing Using DSSS for Lower PAPR
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Solution Overview
Problem
Frequency-division multiplexing (FDM) systems face high peak-to-average-power ratio (PAPR) and susceptibility to interference, especially in long-range transmissions, which affects power consumption and resilience.
Innovation Solution
Implementing direct sequence spread spectrum (DSSS) and single carrier-frequency-division multiple access (SC-FDMA) to spread information across time and frequency bands, using a single carrier signal and differential encoding to reduce PAPR and enhance resilience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If orthogonal frequency-division multiplexing (OFDM) is used to achieve high data throughput, then data throughput is improved, but peak-to-average-power ratio (PAPR) increases
Solution Approach 1:
The patent segments the frequency spectrum into multiple orthogonal subcarriers, each carrying a portion of the data stream. This segmentation allows parallel transmission of multiple data streams simultaneously, achieving high throughput while maintaining lower PAPR compared to single-carrier systems through the orthogonal structure.
Solution Approach 2:
The system employs periodic modulation schemes where data is encoded in periodic waveforms with controlled peak characteristics. By using periodic actions in the modulation process, the system maintains predictable power patterns that reduce peak power requirements while preserving high data transmission capacity.
2Productivity
If frequency-division multiplexing with multiple carriers is used to increase data capacity, then data throughput is improved, but susceptibility to interference increases
Solution Approach 1:
Each subcarrier is assigned specific local frequency characteristics and orthogonal properties that make it resilient to certain types of interference. The local quality of each subcarrier's spectral distribution and phase relationship provides targeted protection against interference at specific frequencies while maintaining overall system throughput.
Solution Approach 2:
The system combines multiple orthogonal subcarriers into a composite signal structure where the orthogonal relationships create interference-resistant properties. This composite approach allows the system to achieve both high throughput and improved reliability by leveraging the collective interference-mitigation capabilities of the orthogonal frequency components.
3Length of moving object
If high power transmission is used to extend communication range, then communication range is improved, but power consumption increases
Solution Approach 1:
The system changes key transmission parameters including using lower peak power levels combined with efficient orthogonal modulation to achieve extended range. By optimizing parameters such as subcarrier spacing, modulation order, and power distribution across subcarriers, the system extends communication range without proportionally increasing overall power consumption.
Data Source
AI summary
A method is provided. In some examples, the method includes generating, by processing circuitry, a spread of chips representing an input bit. In addition, the method includes converting, by the processing circuitry, the spread of chips to a plurality of symbols comprising a pair of symbols. The method also includes mapping, by the processing circuitry, the pair of symbols to a single carrier signal and generating, by the processing circuitry, a radio-frequency (RF) signal based on the single carrier signal. The method further includes transmitting, by the processing circuitry via an antenna, the RF signal.