Communication Device PAPR Reduction via Iterative CAZAC Arithmetic
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Solution Overview
Problem
In OFDM communication, the high peak-to-average power ratio (PAPR) of baseband signals requires wide-range linear amplifiers, and existing techniques struggle to effectively lower PAPR and control its reduction.
Innovation Solution
A communication device and method that uses a CAZAC data series to adjust the number of elements in subcarrier modulated signals through arithmetic operations and IFFT, iteratively optimizing the PAPR by changing the number of elements until it meets a given criterion, and employs shifting and correlation determination for accurate data extraction and demodulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional OFDM modulation is used, then transmission capacity is maintained, but peak-to-average power ratio becomes excessively high requiring wide-range linear amplifiers
Solution Approach 1:
The subcarrier modulated signals are segmented into multiple groups, and only a selected portion (first number of elements) is used in the arithmetic operation with the data series, while the remaining elements are excluded. This segmentation approach controls the PAPR by limiting the contribution of certain signal components
Solution Approach 2:
The invention changes the parameter of element count (first number and second number) in the arithmetic operation between subcarrier modulated signals and data series. By adjusting these counts, the PAPR can be controlled to meet target values while maintaining transmission quality
2Power
If the number of elements in arithmetic operation is increased to lower PAPR, then amplifier efficiency improves, but data extraction accuracy may be compromised
Solution Approach 1:
The receiving device performs correlation determination between extracted data and original data series to verify extraction accuracy. The system uses feedback from correlation results to adjust the number of elements used in arithmetic operations, ensuring both PAPR control and data accuracy
Solution Approach 2:
The invention replaces direct signal manipulation with arithmetic operations using data series multiplication. This substitution allows for more precise control over signal characteristics while maintaining data integrity through the mathematical properties of the data series
3Reliability
If iterative optimization is performed to control PAPR, then transmission quality improves, but processing time increases
Solution Approach 1:
The transmitting device pre-calculates and determines the optimal number of elements (first number and second number) for arithmetic operations before actual data transmission. This preliminary determination avoids iterative processing at the receiving end, reducing processing time while maintaining transmission quality
Data Source
AI summary
The modulator creates modulated signals from input signals. The series/parallel converter creates subcarrier modulated signals from the remaining data and modulated signals. The arithmetic operator arranges and combines a first number of elements of the subcarrier modulated signals from the first one and a second number of elements of a data series from the first one each multiplied by a given amplitude coefficient to create arithmetic operation data. The IFFT executor executes the inverse fast Fourier transformation of the arithmetic operation data. The combiner creates baseband signals from the arithmetic operation results. The determiner calculates the peal-to-average power ratio of the baseband signals. The processing of the arithmetic operator to the determiner is repeated while changing at least one of given numbers until the baseband signals complying with a given criterion are detected. The transmitter creates transmission signals from the baseband signals and transmits the transmission signals via an antenna.