Orthogonal Waveform Modulation for WRAN Spectral Efficiency
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Solution Overview
Problem
Conventional WRAN systems face inefficiencies in utilizing the entire frequency band and struggle with suppressing out-of-band emissions, leading to suboptimal performance and interference issues.
Innovation Solution
The method involves generating a set of orthogonal waveforms for specific frequency subbands within a predetermined frequency band, allowing for efficient modulation and transmission, which enables full power utilization and reduces interference by using digital processing techniques without requiring analog devices like mixers or oscillators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional OFDM/OFDMA technology is used in WRAN systems, then the system can provide wireless high speed internet connections, but the entire frequency band is not fully utilized and out-of-band emission is difficult to suppress
Solution Approach 1:
The frequency band is divided into multiple subbands, and orthogonal waveforms are generated for each subband. This segmentation allows precise control of spectral distribution, enabling full utilization of the frequency band while suppressing out-of-band emissions through the orthogonal properties of the waveforms.
Solution Approach 2:
The patent employs waveform modulation with adjustable parameters including spectral amplitude as a function of frequency, where the spectral amplitude equals substantially zero outside a frequency subband and equals substantially a constant number within the frequency subband. This parameter control enables efficient frequency band utilization while suppressing out-of-band emissions.
2Productivity
If waveform modulation with digital processing is used, then spectral efficiency and transmit power are improved, but system complexity increases
Solution Approach 1:
The patent replaces conventional analog devices (mixers, oscillators) with digital processing techniques for waveform generation and modulation. This substitution achieves improved spectral efficiency and transmit power while managing system complexity through digital signal processing.
Solution Approach 2:
The orthogonal waveforms generated for different subbands can be modulated and transmitted simultaneously, allowing a single system to handle multiple frequency subbands and data streams. This multi-functionality improves spectral efficiency without proportionally increasing complexity.
3Object-generated harmful factors
If the frequency band is divided into multiple subbands with orthogonal waveforms, then out-of-band rejection is improved, but the device complexity increases
Solution Approach 1:
The frequency band is segmented into multiple subbands, each assigned an orthogonal waveform. This segmentation achieves improved out-of-band rejection because the orthogonal waveforms have spectral amplitude equal to substantially zero outside their designated subbands, while the complexity is managed through systematic waveform generation.
Solution Approach 2:
The patent uses substantially constant spectral amplitude within each frequency subband and substantially zero amplitude outside the subband. This homogeneous spectral distribution simplifies the waveform generation process while maintaining excellent out-of-band rejection properties.
Data Source
AI summary
A method and system for transmitting data in a wireless network. The method includes generating a plurality of waveforms corresponding to a plurality of frequency subbands for a predetermined frequency band. The predetermined frequency band is divided into a plurality of groups of subbands, and the plurality of groups of subbands being divided into the plurality of frequency subbands. Additionally, the method includes receiving a data signal, processing information associated with the received data signal, modulating the plurality of waveforms based on at least information associated with the received data signal, and transmitting the modulated plurality of waveforms. Any two of the plurality of waveforms are substantially orthogonal to each other. Each of the plurality of waveforms corresponds to a waveform frequency spectrum associated with a spectral amplitude as a function of a frequency.