Tone Reservation Carrier Index Optimization for OFDM PAPR Reduction
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Solution Overview
Problem
The high peak-to-average power ratio (PAPR) in Orthogonal Frequency Division Multiplexing (OFDM) signals leads to inefficient transmission and reception due to distortion caused by high power amplifiers operating outside their linear range, degrading system performance.
Innovation Solution
A method for determining carrier indices reserved for PAPR reduction using tone reservation, where a tone reservation signal is allocated to specific carriers to minimize the PAPR by generating and comparing kernel signals, and re-arranging indices to optimize the allocation of reserved tones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If OFDM scheme is used for high-speed data transmission, then transmission speed and multipath fading resistance are improved, but PAPR becomes very high causing amplifier distortion and system performance degradation
Solution Approach 1:
The patent extracts the harmful peak components from the OFDM signal by identifying and isolating the carrier indices that generate peak signals. By separating these peak-generating carriers from the overall signal, the invention can apply targeted PAPR reduction without affecting the overall transmission performance of the OFDM system.
Solution Approach 2:
The invention applies local quality by treating different carriers differently based on their peak-generating characteristics. Instead of uniform processing, the patent identifies specific carrier indices that cause peaks and applies specialized tone reservation only to those carriers, while other carriers maintain their normal data transmission function.
2Object-affected harmful factors
If tone reservation signal is allocated to reduce PAPR, then peak signal amplitudes are minimized, but system complexity increases due to carrier index selection and comparison processes
Solution Approach 1:
The patent performs preliminary action by pre-determining the carrier indices that will be used for tone reservation before actual signal transmission. The carrier selection process is performed in advance, allowing the system to prepare the reserved tone allocation strategy beforehand, which simplifies the real-time signal processing.
Solution Approach 2:
The invention implements feedback by comparing the average amplitudes of peak signals generated by different carrier index sets. The system evaluates the results of different tone reservation allocations and uses this feedback information to select the optimal carrier indices that minimize PAPR while maintaining acceptable system complexity.
Data Source
AI summary
A method of determining reserved tones to be used for reduction of a peak to average power ratio (PAPR) of a signal includes: randomly selecting carrier indices for the reserved tones and generating a kernel signal based on the randomly selected carrier indices for the reserved tones; calculating a comparison reference average value of the kernel signal, comparing the calculated comparison reference average value with a prestored comparison reference average value, and preliminarily determining carrier indices of the reserved tones based on the comparison; re-arranging an order of the preliminarily determined carrier indices of the reserved tones; calculating comparison reference average values of kernel signals generated by changing each of the re-arranged carrier indices of the reserved tones, and finally determining carrier indices of the reserved tones which generate a kernel signal having the smallest comparison reference average value among the comparison reference average values as indices of the reserved tones.