Time-Diversity Transmitter for Beyond-Line-of-Sight Blockage Mitigation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current beyond line of sight (BLOS) communication systems, particularly for rotary-wing aircraft and rail platforms, experience periodic outages due to blockages like rotor blades and overhead structures, limiting data rates to low levels such as UHF SATCOM and Inmarsat's L-band GAN, which cannot keep pace with modern bandwidth demands.
Innovation Solution
Implementing a method that includes determining a transmit delay based on blockage characteristics to reschedule data packet transmission, using time-diversity techniques to ensure data packets are transmitted before and after anticipated blockages, and dynamically updating these delays based on real-time blockage data to maintain continuous communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional low data rate systems (UHF SATCOM, L-band GAN) are used for rotary-wing aircraft communications, then reliability during blockage events is maintained, but data rate is limited and cannot keep pace with modern bandwidth demands
Solution Approach 1:
The system performs preliminary actions by transmitting duplicate data packets at different times before blockage events occur. The gateway determines transmit delays based on anticipated blockage characteristics and schedules packets to be transmitted at multiple time instances, ensuring that at least one packet arrives successfully even when blockages occur during transmission.
Solution Approach 2:
The invention implements periodic action by establishing regular transmission cycles where data packets are sent at multiple scheduled times according to determined transmit delays. This periodic multi-transmission approach ensures continuous communication capability by distributing transmission attempts across different time periods, overcoming the limitation of single-transmission conventional systems.
2Productivity
If time-diversity transmission with duplicate packets is implemented, then data rate is improved for obstructed terminals, but system complexity increases due to transmit delay determination and packet scheduling
Solution Approach 1:
The system applies self-service by having the gateway autonomously determine transmit delays and manage packet scheduling without requiring complex external control. The gateway monitors communication activity and blockage characteristics, automatically calculates appropriate delays, and schedules duplicate transmissions independently, reducing the need for complex centralized coordination or manual intervention.
Solution Approach 2:
The invention uses parameter changes by dynamically adjusting transmit delay values based on real-time blockage characteristics and communication activity. The gateway modifies transmission parameters (timing, scheduling) according to current channel conditions, allowing the system to adapt to varying blockage patterns while managing complexity through parameter-based control rather than structural complexity.
3Reliability
If transmit delay is dynamically updated based on real-time blockage data, then communication continuity is improved, but processing time and computational requirements increase
Solution Approach 1:
The system performs preliminary determination of transmit delays based on anticipated blockage characteristics before actual blockages occur. By pre-calculating appropriate delays and establishing transmission schedules in advance, the system reduces real-time processing requirements during communication operations, maintaining continuity while minimizing computational overhead.
Solution Approach 2:
The invention implements feedback mechanisms where the gateway monitors communication activity and receives blockage data from remote terminals to dynamically adjust transmit delays. This feedback loop allows the system to learn from actual channel conditions and optimize transmission timing, improving continuity through adaptive control while managing processing time through efficient feedback-based adjustments rather than continuous complex computation.
Data Source
AI summary
Techniques for enabling broadband data rates at mobile terminals in a beyond-line-of-sight communication system are disclosed. Forward link time-diversity transmission methods and a time-diversity transmitter based upon blockage characteristics are provided. The transmitter optionally supports selective time-diversity and can operate at Ku-band or higher frequencies. A forward link time-diversity receiver and methods for receiving a forward link time-diversity signal are also disclosed. The forward link time-diversity receiver optionally provides low-jitter or low-delay characteristics. A return link transmitter and return link transmit methods which avoid blockages are also disclosed. The return link transmitter can include a signal presence detector and blockage prediction filter.