Guard Period Waveform Matching for Sinc Leakage Reduction
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Solution Overview
Problem
Current communication systems face challenges in reducing discontinuities between waveforms, leading to interference issues, especially in opportunistic channel reuse scenarios where power amplifiers operate below maximum capacity, resulting in sinc leakage and inefficient filtering for suppressing unwanted emissions.
Innovation Solution
The system employs a processor and memory configured to determine the amplitude and derivatives of symbol waveforms, inserting a guard period waveform that matches the amplitude and derivatives at the endpoints of adjacent symbol waveforms, thereby reducing discontinuities and minimizing unwanted emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional filtering is used to suppress unwanted emissions in OFDM and SC-FDMA signal generation, then sidelobe levels are reduced, but the filtering becomes inefficient when power amplifiers operate below maximum capacity, resulting in increased sinc leakage
Solution Approach 1:
The patent applies preliminary action by pre-matching the amplitudes and derivatives of adjacent symbol waveforms before transmission. By ensuring continuity conditions are met in advance through careful waveform design and selection of symbol boundaries, the system prevents sinc leakage at its source rather than relying on filtering to suppress it afterward. This is particularly effective when power amplifiers operate below maximum capacity, where conventional filtering becomes inefficient.
2Object-generated harmful factors
If guard periods are extended to reduce discontinuities between waveforms, then out-of-band emissions are suppressed, but spectral efficiency decreases and computational complexity increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the continuity conditions at waveform boundaries based on the specific characteristics of adjacent symbols. By modifying the amplitude and derivative matching parameters at guard period boundaries, the system achieves effective suppression of out-of-band emissions with shorter guard periods, thereby maintaining spectral efficiency while reducing computational complexity compared to conventional extended guard period approaches.
3Object-generated harmful factors
If the amplitude and derivatives of symbol waveforms are precisely matched at boundaries, then discontinuities are reduced and sinc leakage is minimized, but device complexity increases
Solution Approach 1:
The patent applies local quality by focusing computational resources on matching amplitudes and derivatives only at the critical boundary points between adjacent symbols, rather than throughout the entire waveform. This localized approach to continuity matching effectively reduces waveform discontinuities and sinc leakage while minimizing the overall computational complexity burden on the communication device.
Data Source
AI summary
An apparatus, method and system for reducing discontinuities between waveforms in a communication system. In one embodiment, an apparatus includes a processor and memory including computer program code. The memory and the computer program code are configured, with the processor, to determine an amplitude and set of derivatives at an end point of a first symbol waveform, and determine an amplitude and set of derivatives at a beginning point of a second symbol waveform. The memory and the computer program code are configured, with the processor, to insert a guard period waveform having an amplitude and set of derivatives at a first end to substantially match the amplitude and set of derivatives at the end point of the first symbol waveform and an amplitude and set of derivatives at a second end that substantially matches the amplitude and set of derivatives at the beginning point of the second symbol waveform.