Single IFFT PAPR Reduction via Shift Register Masking
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Solution Overview
Problem
The existing OFDM communication systems face high system complexity and increased costs due to the need for multiple IFFTs in the SLM scheme to reduce PAPR, which complicates the transmitter design and increases production costs.
Innovation Solution
The proposed solution involves using a single IFFT and shift registers to perform the necessary transformations, allowing for the sharing of IFFT operations across multiple signal sequences, thereby reducing the number of IFFTs required and simplifying the transmitter design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple IFFTs are used in the SLM scheme to reduce PAPR, then the PAPR reduction performance is improved, but the device complexity and production cost increase
Solution Approach 1:
The patent combines multiple IFFT operations into a single IFFT by merging the signal processing paths. Instead of using U separate IFFTs for U different phase series, the invention processes all phase series through one shared IFFT unit, thereby reducing hardware complexity while maintaining PAPR reduction capability.
Solution Approach 2:
The single IFFT unit is designed to perform multiple functions by processing different phase series sequentially or through time-multiplexed operations. This universal IFFT structure replaces the need for multiple dedicated IFFT units, reducing overall system complexity while preserving the ability to generate U different signal sequences for PAPR comparison.
2Reliability
If multiple IFFTs are used in the SLM scheme to reduce PAPR, then the PAPR reduction performance is improved, but the production cost increases
Solution Approach 1:
By merging multiple IFFT functions into a single hardware unit, the patent reduces the bill of materials and assembly requirements. This consolidation directly lowers production costs while maintaining the capability to generate multiple phase series for effective PAPR reduction.
3Reliability
If the number of phase series U is increased in the SLM scheme, then the PAPR reduction effectiveness is improved, but the calculation complexity and transmitter complexity increase
Solution Approach 1:
The patent introduces dynamic switching and time-multiplexed processing to handle multiple phase series through a single IFFT unit. The system dynamically configures the processing path based on which phase series is being processed, allowing U different sequences to be generated through one IFFT with appropriate switching control, thereby reducing static hardware complexity.
Data Source
AI summary
A transmitter apparatus and method for reducing PAPR in an OFDM system. The transmitter apparatus performs a masking process on an input signal block using a plurality of mask sequences in an OFDM system, and selects a specific sequence having a lowest PAPR among IFFT-processed results. The apparatus includes a single IFFT for performing an IFFT process on the received signal block, and generating an IFFT-processed sequence; a plurality of shift registers for storing individual bits of the IFFT-processed sequence, cyclically shifting them, and generating the cyclically-shifted bits; a plurality of multiplier groups for multiplying coefficients determined by corresponding mask sequences by the output bits of the shift registers; and a plurality of adders corresponding to the plurality of multiplier groups for adding the multiplied results of the multiplier groups, thereby reducing system complexity and production costs.