OFDM Sub-band Inversion for PAPR Suppression
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Solution Overview
Problem
High peak to average power ratios in electronic communications negatively impact the cost and operation of receivers, as conventional methods fail to effectively suppress these ratios, leading to inefficiencies and increased operational costs.
Innovation Solution
A system and method for peak to average power ratio suppression using a transmitter with a system on chip (SoC), orthogonal frequency division multiplexing (OFDM) circuit, IFFT circuit, sub-band processing, and inversion descriptor generation, which inverts and combines OFDM subcarriers to reduce the peak-to-average-power ratio below a threshold, allowing for efficient transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional transmission methods are used, then transmission simplicity is maintained, but peak to average power ratio remains high causing negative impacts on receiver cost and operation
Solution Approach 1:
The transmission signal is segmented into multiple OFDM subcarriers that can be independently processed. The method divides the broadband signal into narrower sub-bands, applies different inversion operations to each sub-band, and then combines them. This segmentation allows selective manipulation of signal components to suppress peak power while maintaining overall transmission functionality.
Solution Approach 2:
The core invention applies inversion operations to OFDM subcarriers to suppress peak power. Specifically, the method inverts (negates) selected subcarriers in a first OFDM symbol and combines them with corresponding subcarriers in a second OFDM symbol. This inversion approach directly counteracts peak power formations by reversing the polarity of problematic signal components.
2Productivity
If peak to average power ratio is suppressed through sub-band processing, then transmission efficiency is improved, but processing complexity increases
Solution Approach 1:
The signal processing is segmented into discrete sub-band operations that can be efficiently implemented using standard OFDM processing blocks. Each sub-band is processed independently through inversion and combination operations, allowing parallel processing and reducing overall computational complexity compared to processing the entire broadband signal at once.
Solution Approach 2:
The inversion operations are performed preliminarily on the OFDM subcarriers before final signal combination and transmission. By pre-processing the subcarriers with inversion operations and preparing the combined signal in advance, the system avoids complex real-time processing during transmission, thereby improving overall transmission efficiency.
Data Source
AI summary
A transmitter may comprise a first domain translation circuit, a first PAPR suppression circuit, and a descriptor generation circuit. The first domain translation circuit may convert a plurality of frequency-domain symbols of a first OFDM symbol to a corresponding plurality of first time-domain signals. The first PAPR suppression circuit may group the plurality of first time-domain signals into a plurality of sub-bands of the first time-domain. The first PAPR suppression circuit may invert one or more of the sub-bands of the first time-domain signals according to a value of a first descriptor. The descriptor generation circuit may determine the value of the first descriptor using an iterative process in which each iteration comprises random selection of a value of the first descriptor, determination of a PAPR of the first OFDM symbol processed using the randomly-selected value, and determination of whether said PAPR meets one or more determined criteria.