OFDM Tone Set Zero Padding for ACLR Reduction
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Solution Overview
Problem
Wireless communication networks face challenges in reducing adjacent channel leakage-power ratio (ACLR) due to discontinuity between consecutive OFDM symbols, leading to inter-carrier interference.
Innovation Solution
The method involves de-assigning and processing channel equalized signals into tone sets, performing zero padding on certain tones, and converting between frequency and time domains to minimize ACLR by ensuring smooth transitions between OFDM symbols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional OFDM signal processing is used, then communication speed and data transmission efficiency are maintained, but discontinuity between consecutive OFDM symbols causes inter-carrier interference and increases ACLR
Solution Approach 1:
The patent applies preliminary action by performing zero-padding on tone sets before converting them back to the frequency domain. Specifically, after converting first and third tone sets to time domain (fourth and fifth tone sets), the patent detects zero-padding and converts them back to frequency domain (sixth and seventh tone sets) before final signal assembly. This preliminary processing prevents discontinuity between consecutive OFDM symbols, thereby reducing ACLR and inter-carrier interference while maintaining overall system performance.
2Reliability
If zero padding is applied to reduce discontinuity, then inter-carrier interference is reduced, but processing time and computational overhead increase
Solution Approach 1:
The patent applies local quality by selectively applying zero-padding only to specific tone sets (first and third tone sets corresponding to time-domain converted signals) rather than uniformly processing all tones. The method detects zero-padding conditions and applies frequency-domain conversion only where needed (to sixth and seventh tone sets), thereby reducing discontinuity at critical symbol boundaries while minimizing unnecessary processing overhead and maintaining efficiency.
3Reliability
If tone sets are converted between frequency and time domains multiple times, then ACLR is reduced through smooth transitions, but computational complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the OFDM signal into multiple distinct tone sets (first, second, third, fourth, fifth, sixth, and seventh tone sets) and processing each segment differently. The first and third tone sets are converted to time domain (fourth and fifth), selectively zero-padded, and then converted back to frequency domain (sixth and seventh). This segmented approach allows precise control over transitions between consecutive OFDM symbols, reducing ACLR while managing computational complexity through targeted processing of specific segments rather than uniform processing of the entire signal.
Data Source
AI summary
Adjacent channel leakage-power ratio (ACLR) can be reduced at a transmitter of a device. A modulated signal can be mapped into a plurality of tone sets in a frequency domain, wherein the plurality of tone sets include a first, a second, and a third set of tones. The first and the third set of tones can be converted in the frequency domain to a fourth and a fifth set of tones, respectively, in a time domain. A zero padding of one or more symbols associated with the fourth and the fifth set of tones can be performed to output a sixth and a seventh set of tones, respectively. The sixth and the seventh set of tones can be converted to an eighth and a ninth set of tones, respectively, in the frequency domain. The eighth and the ninth set of tones can be processed for transmitting to another wireless device.