SC-FDMA Signal Generation Using Recursive CAZAC Phase Calculation
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Solution Overview
Problem
SC-FDMA signal generation consumes more hardware resources due to the need for DFT operations when processing CAZAC sequences, particularly for prime sequence lengths, which is inefficient and resource-intensive.
Innovation Solution
A method and device for generating SC-FDMA signals using an analytical representation of CAZAC sequences in the frequency domain with integer phase terms, calculated recursively, eliminating the need for DFT operations and reducing computational complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If DFT operations are used to generate CAZAC sequences in SC-FDMA, then the signal generation follows the conventional modulator structure, but hardware resource consumption increases and processing efficiency decreases
Solution Approach 1:
The patent extracts and eliminates the DFT operation from the SC-FDMA signal generation process. By recognizing that CAZAC sequences have known frequency domain representations, the invention removes the unnecessary DFT block from the conventional modulator structure, directly generating the frequency domain signal without the intermediate DFT transformation step.
Solution Approach 2:
Instead of following the conventional approach of transforming time domain symbols through DFT to frequency domain, the patent inverts the process by directly generating the frequency domain representation of CAZAC sequences using their analytical properties, then transforming to time domain only when needed.
2Ease of operation
If DFT operations are performed on CAZAC sequences with prime sequence lengths, then the conventional SC-FDMA processing is maintained, but computational complexity increases and hardware resources are consumed
Solution Approach 1:
The patent changes the approach from numerical computation (DFT) to analytical generation. By utilizing the closed-form frequency domain representation of CAZAC sequences and calculating phase terms recursively, the invention transforms the problem from a computationally intensive matrix operation to a sequence of simple arithmetic calculations, significantly reducing hardware complexity.
Solution Approach 2:
The patent replaces the mechanical DFT computation system with an analytical calculation system. Instead of using hardware accelerators or complex algorithms to perform DFT operations, the invention uses direct mathematical formulas and recursive phase calculations, substituting a resource-intensive computational mechanism with an efficient analytical one.
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AI summary
A technique for generating a Single-Carrier Frequency Division Multiple Access (SC-FDMA) signal based on a Constant Amplitude Zero Auto-Correlation (CAZAC) sequence is disclosed. A method embodiment of this technique comprises generating a frequency domain representation of the CAZAC sequence by providing an analytical representation of the CAZAC sequence in the frequency domain with an integer phase term and calculating the integer phase term in a recursive manner for each of a plurality of frequency domain samples of the CAZAC sequence. The resulting frequency domain representation of the CAZAC sequence is then mapped to a predetermined frequency location before being transformed into the time domain to obtain a time domain representation of the SC-FDMA signal. The SC-FDMA signal may be a random access signal for transmission on a Physical Random Access Channel (PRACH).