Wireless Frame Formatting via Downclocking Ratios
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently operating within frequency spectra typically used by television channels, requiring stringent spectral mask requirements and attenuation to avoid interference, while also needing to adapt to varying channel bandwidths and interference conditions.
Innovation Solution
The implementation of downclocking ratios, such as N=4 and N=8, to generate different channel widths that fit within the 6 MHz bandwidth of TV channels, allowing for efficient operation by adjusting the symbol duration and guard interval to meet spectral mask requirements and improve delay spread immunity, while also optimizing MAC throughput and preamble length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If wireless communication systems operate within TV channel frequency spectra, then spectrum utilization is improved, but spectral mask requirements and attenuation become more stringent
Solution Approach 1:
The patent segments the available spectrum into multiple sub-channels or frequency bins within the TV white space. By dividing the frequency spectrum into smaller discrete units, the system can selectively activate only those sub-channels that meet spectral mask requirements, thereby utilizing available spectrum efficiently while maintaining necessary attenuation to protect TV channel operations.
Solution Approach 2:
The patent implements dynamic spectrum access where the communication system continuously monitors TV channel usage and adapts its transmission parameters in real-time. This includes dynamically adjusting transmit power, selecting available frequency bins, and modifying modulation schemes based on detected TV signal presence, enabling the system to operate within spectral masks while maximizing spectrum utilization when TV channels are inactive.
2Reliability
If downclocking ratio N=8 is used, then delay spread immunity is improved, but symbol duration increases
Solution Approach 1:
The patent employs parameter changes by implementing multiple downclocking ratios (N=4 and N=8) that adjust the sampling rate and symbol duration. By changing the downclocking ratio parameter, the system can optimize between delay spread immunity (achieved with higher N=8) and transmission speed (maintained with lower N=4), allowing adaptive selection based on channel conditions.
Solution Approach 2:
The patent dynamically selects between different downclocking ratios based on channel conditions. When delay spread is detected to be high, the system switches to N=8 for better immunity. When channel conditions are favorable and delay spread is low, the system uses N=4 to maintain shorter symbol durations and higher throughput, thus adapting the symbol duration to actual propagation conditions.
3Object-affected harmful factors
If guard interval is increased to meet spectral mask requirements, then spectral compliance is improved, but data transmission time decreases
Solution Approach 1:
The patent segments the transmission frame into multiple parts with different guard interval requirements. By dividing the data transmission into multiple segments or frequency bins, the system can apply shorter guard intervals to segments that are less sensitive to spectral leakage, while using longer guard intervals only where necessary to meet spectral mask requirements, thereby reducing overall transmission time.
Solution Approach 2:
The patent applies local quality by using different guard interval lengths for different frequency bins or sub-channels based on their specific spectral characteristics. Instead of uniformly applying a long guard interval across all frequencies, the system tailors the guard interval length to the local spectral requirements of each frequency bin, minimizing the impact on data transmission time while ensuring spectral mask compliance where needed.
Data Source
AI summary
Frame formatting for communications within single user, multiple user, multiple access, and/or MIMO wireless communications. A signal is processed within a communication device using at least two respective downclocking ratios (e.g., a first downclocking ratio applied to a first portion of the signal such as a frame or packet extracted there from, a second downclocking ratio applied to a second portion of the signal). Alternatively, a signal is divided into more than two respective portions, and different respective downclocking ratios are applied to those different respective portions (e.g., a first downclocking ratio applied to a first portion of the signal, and so on up to an n-th downclocking ratio applied to an n-th portion of the signal). Some implementations apply a singular or common downclocking ratio to more than one portion of the signal (which may be contiguous/adjacent or non-contiguous/non-adjacent within the signal).