Link 16 Terminal IEM Detection via Multi-Slot Segmentation
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Solution Overview
Problem
Link 16 terminals currently require a significant amount of time to detect an initial entry message (IEM) and enter an active network, which can be delayed by interference or timing errors, leading to prolonged network entry processes.
Innovation Solution
A CMN-4 enhanced Link 16 terminal is configured to detect an IEM at four different times within the same time slot on the same net number, using a modified software process that calculates optimal detection times based on the current time and error window, allowing for simultaneous reception of multiple messages and reducing the time needed for initial entry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a terminal uses conventional single-time-slot IEM detection, then the detection process is simple, but the network entry time is prolonged (several minutes)
Solution Approach 1:
The patent segments the IEM detection process by configuring the receiver to detect IEMs at four different time slots within the same net number instead of a single time slot. This segmentation of the detection process across multiple time slots allows the terminal to capture the IEM more quickly, reducing network entry time from several minutes to as little as 24 seconds while distributing the detection effort across multiple opportunities
Solution Approach 2:
The patent applies preliminary action by pre-calculating four different time slots where IEM detection should occur, based on the current terminal time and an error window. This preliminary configuration of multiple detection opportunities before actual network entry begins allows the terminal to immediately start detection at optimized times, eliminating the prolonged waiting period of conventional single-slot detection
2Productivity
If a terminal detects IEM at multiple time slots, then the time to enter the network is reduced, but the complexity of the detection process increases
Solution Approach 1:
The patent changes the parameter of detection timing by configuring the receiver to monitor four different time slots instead of one. The software calculates these time slots based on the terminal's current time and an error window, creating a set of optimized detection opportunities. This parameter change from single-slot to multi-slot detection increases network entry speed while the calculation-based approach keeps the added complexity manageable
3Reliability
If a terminal uses a single time reference for IEM detection, then the detection process is straightforward, but it is vulnerable to timing errors and interference
Solution Approach 1:
The patent applies beforehand cushioning by incorporating an error window into the time slot calculation process. The four detection time slots are calculated to account for potential timing errors in the terminal's current time reference. This cushioning against timing errors before detection begins ensures that even if the terminal's time reference is slightly off, the IEM detection will still succeed at one of the four configured time slots, improving reliability while using a relatively simple calculation-based approach
Data Source
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AI summary
A process for allowing a CMN-4 equipped Link 16 terminal to enter an active network. After an initial entry command is entered at the terminal at a given current time at the terminal, a number of time slots are identified in which multiple receivers at the terminal have an opportunity to detect an initial entry message (lEM) after the given current time. Each of the receivers is set to detect an lEM during a different one of the identified time slots. When an lEM is first detected by one of the receivers, the current time at the terminal is reset based on the time slot in which the I EM was detected.