Double-Side Extended Slepian Waveforms for Low Out-of-Band Emissions
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Solution Overview
Problem
Existing wireless communication technologies face challenges in generating signals with well time-frequency localization due to the characteristics of radio channels and diverse communication system requirements, leading to inefficiencies in spectral containment and increased out-of-band emissions.
Innovation Solution
The generation and reception of signals using discrete prolate spheroidal (DPS) sequences, where extension symbols are appended to the sequences based on convolution, enabling the creation of Slepian-based waveform (SWF) signals with improved spectral containment and reduced out-of-band emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If discrete prolate spheroidal sequences are applied in wireless communication, then spectral containment is maximized, but implementation becomes non-straightforward due to radio channel characteristics and system requirements
Solution Approach 1:
The sequence is divided into two parts: the original DPS sequence and appended extension symbols. This segmentation allows the system to maintain the spectral containment properties of the DPS sequence while adding structure that simplifies implementation in wireless channels by enabling easier synchronization and channel estimation.
Solution Approach 2:
Extension symbols are appended in advance to the DPS sequence before transmission. This preliminary action prepares the signal structure to handle radio channel characteristics proactively, making the implementation more straightforward by pre-establishing reference points for synchronization and channel estimation operations.
2Object-generated harmful factors
If extension symbols are appended to DPS sequences, then out-of-band emissions are reduced, but sequence length increases
Solution Approach 1:
The extension symbols, which necessarily increase sequence length, are constructed to convert this apparent disadvantage into a benefit by reducing out-of-band emissions. The extension symbols are derived from the original DPS sequence through convolution and normalization, transforming the length increase into a mechanism for spectral containment and harmful emission reduction.
3Loss of energy
If convolution-based extension symbols are used, then spectral containment improves, but computational complexity increases
Solution Approach 1:
The extension symbols are obtained by changing parameters of the original DPS sequence through convolution with the sequence itself and normalization by eigenvalues. This parameter transformation approach maintains spectral containment while providing a systematic method that can be efficiently implemented through pre-computed eigenvalue normalization factors.
Data Source
AI summary
A device may obtain an input symbol sequence for transmission. The device may further obtain a set of DPS sequences associated with Ni highest eigenvalues of a Slepian matrix and a set of extended sequences comprising the set of DPS sequences appended with extension symbols derived based on a convolution of respective DPS sequences. The device may modulate the set of extended sequences based on the input symbol sequence to generate a signal comprising Slepian-based waveform symbol(s). Another device may receive the signal, remove the extension symbols, and demodulate Slepian-based waveform symbol(s) of the signal based on the set of DPS sequences.