PAPR Suppression via Parallel OFDM Sub-band Inversion
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Solution Overview
Problem
High peak to average power ratios in electronic communications systems lead to increased costs and operational challenges for receivers, as conventional methods fail to effectively manage and suppress these ratios.
Innovation Solution
A system and method for peak to average power ratio (PAPR) suppression using a transmitter with circuitry that includes a system on chip (SoC), OFDM circuit, IFFT circuit, sub-band processing, and inversion descriptor generation, which inverts and combines OFDM subcarriers to maintain PAPR below a threshold, employing techniques such as parallel symbol processing and descriptor generation to achieve PAPR reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional transmission methods are used, then system simplicity is maintained, but peak to average power ratio becomes excessively high causing receiver costs and operational challenges to increase
Solution Approach 1:
The transmission system segments the single OFDM signal path into multiple parallel OFDM circuits (at least two), each processing different symbol sequences independently. This segmentation allows each circuit to operate with lower individual PAPR while the combined output achieves overall PAPR suppression, resolving the contradiction between system simplicity and PAPR control.
Solution Approach 2:
The patent merges the outputs of multiple parallel OFDM circuits by combining their respective symbol sequences in the time domain. This combining operation integrates the benefits of multiple low-PAPR signals to produce a composite signal with suppressed peak power, addressing the harmful effects of high PAPR without requiring complete system redesign.
2Object-affected harmful factors
If PAPR suppression techniques are implemented, then peak power levels are reduced, but device complexity increases due to additional circuits and processing
Solution Approach 1:
The system dynamically selects and applies different inversion descriptors to symbol sequences based on real-time PAPR conditions. The parallel OFDM circuits can be selectively activated or deactivated depending on the required PAPR suppression level, allowing the system to adapt its complexity to the actual transmission needs rather than operating at maximum complexity continuously.
Solution Approach 2:
The patent changes key parameters of the OFDM signal processing by applying inversion descriptors that flip the polarity of certain subcarriers or symbol sequences. This parameter change transforms the signal characteristics to reduce peak power levels while maintaining the fundamental OFDM structure, thus suppressing PAPR without proportionally increasing device complexity.
3Object-affected harmful factors
If multiple parallel OFDM circuits are used, then PAPR suppression is achieved, but processing time and computational load increase
Solution Approach 1:
The system performs preliminary PAPR assessment and inversion descriptor selection before the actual symbol transmission. By pre-calculating the appropriate inversion patterns and preparing the parallel circuit configurations in advance, the system minimizes the processing time required during actual symbol transmission, thus reducing the time loss despite using multiple parallel circuits.
Solution Approach 2:
The parallel OFDM circuits are designed to operate independently and self-sufficiently, with each circuit capable of processing its symbol sequence without requiring extensive coordination or data exchange with other circuits. This self-service architecture reduces the computational overhead and processing time by eliminating inter-circuit communication delays while still achieving PAPR suppression through the combining operation.
Data Source
AI summary
A transmitter comprises a first peak-to-average-power ratio (PAPR) suppression circuit and a second peak-to-average-power ratio (PAPR) suppression circuit. The first PAPR suppression circuit may receive a first sequence of time-domain symbols to be transmitted, alter the first sequence based on each of a plurality of symbol ordering and/or inversion descriptors to generate a corresponding plurality of second sequences of time-domain symbols, measure a PAPR corresponding to each of the second sequences, select one of the plurality of symbol ordering and/or inversion descriptors based on the measurement of PAPR, and convey the selected one of the symbol ordering and/or inversion descriptors to the second PAPR suppression circuit. The second PAPR suppression circuit may receive the first sequence of time-domain symbols to be transmitted, and alter the first sequence based on the selected one of the symbol ordering and/or inversion descriptors to generate a reordered and/or inverted symbol sequence.