OFDM Symbol Phase Magnitude Modulation for PAPR Reduction
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Solution Overview
Problem
Conventional methods for reducing Peak to Average Power Ratio (PAPR) in OFDM/OFDMA communication networks are either computationally complex, require modifications to standard specifications, or do not effectively support multiple degrees of freedom, leading to inefficiencies in power usage and data transmission.
Innovation Solution
The method involves modulating the phase and magnitude of OFDM symbols using a low-ripple-filter with an optimization algorithm to generate modulated symbols with reduced PAPR, ensuring positive modulus in the frequency domain without altering the data and maintaining compatibility with existing standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If digital clipping is applied to reduce PAPR before transmission, then unintentional clipping in RF PA is reduced, but spectral spreading occurs requiring additional filtering
Solution Approach 1:
The patent applies preliminary action by performing PAPR reduction through constellation manipulation before transmission. The receiver is pre-configured with knowledge of the manipulation type, allowing it to reverse the manipulation without complex filtering operations. This resolves the contradiction by eliminating the need for additional filtering while maintaining signal integrity.
2Use of energy by moving object
If constellation manipulation is used to reduce PAPR, then power efficiency is improved, but receiver must know manipulation type requiring specification violations
Solution Approach 1:
The patent applies universality by designing a constellation manipulation scheme that serves multiple functions: it reduces PAPR to improve power efficiency while simultaneously maintaining standard compatibility. The receiver determines the manipulation type through standard-compliant signaling mechanisms, allowing the system to achieve both power efficiency and adaptability to existing standards.
3Reliability
If block-coding method is used to reduce PAPR, then PAPR reduction is achieved, but large look-up tables and exhaustive search are required
Solution Approach 1:
The patent applies the taking out principle by extracting the essential PAPR reduction function from complex block-coding methods. Instead of using large look-up tables and exhaustive search, the invention uses simplified constellation manipulation that achieves PAPR reduction through direct phase/magnitude adjustments, eliminating the need for computationally intensive operations while maintaining PAPR control.
4Reliability
If RF PA operates linearly to prevent clipping, then signal quality is maintained, but power efficiency decreases and battery life reduces
Solution Approach 1:
The patent applies preliminary anti-action by preemptively reducing PAPR through constellation manipulation before the signal reaches the RF power amplifier. This prevents the need for the PA to operate in a linear regime, allowing it to operate more efficiently in non-linear modes while still preventing clipping. The result is maintained signal quality with significantly improved power efficiency and extended battery life.
Data Source
AI summary
A method and system of transmitting a plurality of Orthogonal Frequency Division Multiple (OFDM) symbols in a block transmission system of a communication network is provided. The block transmission system is a frequency reuse system. The method includes encoding the plurality of OFDM symbols. The method further includes, modulating at least one of a phase and a magnitude of the plurality of OFDM symbols. Thereafter, a plurality of modulated OFDM symbols is converted from a digital form to an analog form. The plurality of modulated OFDM symbols corresponds to the plurality of OFDM symbols.