Angle Dithering for Troposcatter Communication Throughput
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Solution Overview
Problem
Wireless communication systems face challenges in maintaining reliable communication due to the dominance of slow fading channels, which limit throughput and reliability due to deep fades, as they do not exploit time diversity effectively.
Innovation Solution
Implementing angle dithering techniques by steering antennas at both nodes using coordinated dither patterns to create subsequent common scattering volumes that are decorrelated from the initial ones, thereby inducing fast fading characteristics in channels dominated by slow fading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If angle dithering is implemented to induce fast fading characteristics, then throughput and reliability are improved by exploiting time diversity, but device complexity increases due to coordinated antenna steering mechanisms
Solution Approach 1:
The patent applies dynamics by making the antenna steering angles time-varying through dither patterns. The antennas are dynamically adjusted around the line-of-sight path according to predefined dither patterns (e.g., sinusoidal, random, or triangular patterns), creating time-varying scattering volumes that induce fast fading characteristics and enable time diversity exploitation for improved throughput
Solution Approach 2:
The patent employs periodic action through coordinated dither patterns at both transmitter and receiver antennas. The dither patterns create periodic variations in the scattering volumes, with the receiver's dither pattern synchronized to the transmitter's pattern, generating decorrelated fast fading channels that improve reliability and throughput through time diversity
2Reliability
If angle dithering is implemented to induce fast fading characteristics, then reliability is improved by exploiting time diversity, but ease of operation deteriorates due to coordinated antenna steering requirements
Solution Approach 1:
The system dynamically adjusts antenna steering angles using predetermined dither patterns, transforming the static slow fading channel into a dynamic fast fading channel. This dynamic behavior creates multiple decorrelated fading realizations over time, enabling the receiver to exploit time diversity and improve link reliability through selective combining or chase combining techniques
Solution Approach 2:
The patent applies preliminary action by pre-defining dither patterns at both transmitter and receiver before communication begins. The dither patterns (sinusoidal, random, triangular, etc.) are predetermined and synchronized, allowing the system to proactively create fast fading characteristics and ensure reliable communication without requiring real-time adaptive control
3Reliability
If coordinated dither patterns are used to create decorrelated scattering volumes, then time diversity is exploited for improved communication, but device complexity increases due to synchronization requirements
Solution Approach 1:
The patent uses periodic action through coordinated dither patterns where the receiver's antenna steering follows a pattern synchronized to the transmitter's dither pattern. This coordination ensures that the scattering volumes created at both ends are properly correlated to generate the desired fast fading effect, improving reliability through time diversity while maintaining manageable system complexity through pattern synchronization
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances communication performance by increasing throughput and reliability by exploiting time diversity in fast fading channels, improving the 1% outage capacity and providing robust communication links.
Implementation Method 1
A defining characteristic of the wireless channel is the variations of the channel strength over time and over frequency. The variations can be roughly divided into two types as shown in FIG. 1—slow fading (or large-scale fading) and fast fading (or small-scale fading).
Data Source
AI summary
Methods and systems for improving communication using angle dithering are presented. Embodiments of the present invention provide increased throughput and robustness after link establishment by providing fast fading characteristics in environments dominated by slow fading. In particular, fast fading characteristics are induced by steering the transmitter and receiver antennas in optical and beyond line-of-sight troposcatter communication systems based on dither patterns. In non-line-of-sight (NLOS) communication systems, using coordinated dither patterns at the transmitter and receiver ensures that successive common scattering volumes become decorrelated, whereas in line-of-sight optical communication systems, the dither pattern is based on the tropospheric scintillation in free space traversed by the established link.