Parallel Bit Reversal Unit for FFT Memory Conflict Reduction
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Solution Overview
Problem
Existing bit reversal methods for Fast Fourier Transform (FFT) algorithms are inefficient due to high iteration requirements and scalar data operations, leading to reduced parallelism and increased memory access conflicts, especially when implementing internal data bit-reversal using a processor.
Innovation Solution
A parallel bit reversal device and method utilizing a multi-granularity parallel memory and address selector to perform bit-reversal operations in a butterfly computation and control unit, allowing for parallel processing with reduced memory access conflicts and efficient data grouping, shifting, and reversal operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a processor is used to implement internal data bit-reversal, then the bit reversal operation can be performed, but the operation requires multiple iterations and scalar data processing, resulting in low efficiency
Solution Approach 1:
The patent segments the bit reversal operation into parallel processing units that operate simultaneously on multiple data elements. Instead of processing data sequentially through multiple iterations, the system divides the data into groups and processes them in parallel using vector instructions, eliminating the iterative approach and significantly reducing the time required for bit reversal operations.
Solution Approach 2:
The patent implements dynamic parallel processing capabilities that adapt to different data sizes and processing requirements. The system uses variable-length vector instructions and dynamic thread allocation to optimize the bit reversal operation for different scenarios, allowing the processing throughput to scale with the available hardware resources and data size.
2Productivity
If multiple processing cores are used for parallel bit reversal, then parallel processing is achieved, but memory access conflicts occur among cores, reducing execution efficiency
Solution Approach 1:
The patent assigns specific memory regions and data ranges to different processing cores, ensuring that each core operates on a localized portion of the data. This spatial partitioning of memory access responsibilities eliminates conflicts between cores by ensuring that no two cores attempt to access the same memory location simultaneously. Each core has dedicated access to its assigned memory segment.
3Measurement precision
If lookup table access and shift operations are performed multiple times for address calculation, then bit reversal addresses can be calculated, but the address calculation requires multiple clock cycles, lowering execution efficiency
Solution Approach 1:
The patent pre-calculates and stores bit reversal address mappings in lookup tables before the actual data processing begins. During the bit reversal operation, processing units simply retrieve pre-computed addresses from these tables using direct indexing, rather than performing repeated lookup table accesses and shift operations for each address calculation. This preliminary preparation eliminates the need for multiple clock cycles during the actual processing phase.
Data Source
AI summary
A parallel bit reversal device and method. The device includes a parallel bit reversal unit, a butterfly computation and control unit, and a memory. The butterfly computation and control unit is coupled to the memory via a data bus. The parallel bit reversal unit is configured to bit-reverse butterfly group data used by the butterfly computation and control unit. The parallel bit reversal unit includes an address reversing logic coupled to the butterfly computation and control unit, and configured to perform mirror reversal and right-shift operations on a read address from the butterfly computation and control unit.