Simulcast Signal Equalization Using Preset Time Delay Filters
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Solution Overview
Problem
Simulcast networks face significant performance issues due to time delays between transmitters, leading to symbol errors and non-uniform coverage, especially in high-speed digital transmissions, as existing equalization methods are inadequate for large time delays and require complex GPS devices or high computational overhead.
Innovation Solution
The system uses pre-established time delay filters to determine channel coefficients for signal equalization, generating simulated signals with varying time delays to approximate the actual signal, thereby avoiding complex location-determining devices and reducing computational overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GPS devices or complex equalization methods are used to compensate for time delays, then signal alignment and symbol error rates improve, but device complexity and infrastructure costs increase
Solution Approach 1:
The patent creates simulated versions of the transmitted signal with various predetermined time delays applied. These simulated signals serve as references to compare against the actual received signal, allowing the system to identify which time delay value best matches the actual conditions without requiring complex GPS devices or location determination infrastructure.
Solution Approach 2:
The system pre-calculates and stores multiple simulated signals with different time delay values before actual communication occurs. This preliminary preparation allows for rapid comparison and selection of the appropriate time delay compensation without real-time complex computation, thereby improving reliability while maintaining simple device architecture.
2Reliability
If GPS devices or complex equalization methods are used to compensate for time delays, then symbol error rates improve, but infrastructure costs increase
Solution Approach 1:
Instead of requiring expensive GPS receivers or complex location determination infrastructure at each transmitter site, the patent uses software-based simulation to create reference signals with predetermined time delays. This copying approach achieves the same reliability improvement without the associated infrastructure costs.
Solution Approach 2:
The patent replaces expensive, permanent infrastructure (GPS devices, location determination systems) with inexpensive, software-based simulated signals that can be generated and discarded as needed. This substitution dramatically reduces infrastructure costs while maintaining symbol error rate performance.
3Area of stationary object
If transmitters are spaced farther apart to reduce overlap, then coverage area improves, but time delay differences increase causing more symbol errors
Solution Approach 1:
The patent implements dynamic time delay adjustment by comparing received signals against multiple simulated signals with different time delays. The system adaptively selects and applies the appropriate time delay compensation based on actual signal conditions, allowing transmitters to be spaced farther apart for broader coverage while maintaining symbol error rate performance through dynamic equalization.
Solution Approach 2:
The system changes the time delay parameter dynamically by testing multiple predetermined values and selecting the one that best matches the actual received signal. This parameter adjustment allows the system to compensate for increased time delay differences that result from larger transmitter spacing, thereby maintaining reliability while expanding coverage area.
Data Source
AI summary
A method for facilitating an equalization of a simulcast signal comprising: (a) receiving a simulcast signal comprising known data simulcast from at least two different sites; (b) generating a number of simulated simulcast signals, each simulated simulcast signal being based on at least two sites transmitting said known data with a presumed time delay, each simulated simulcast signal having a different presumed time delay; (c) determining which of said simulated simulcast signals is an optimum simulated simulcast signal that correlates most closely to said simulcast signal; and (d) providing time delay data of said optimum simulated simulcast signal for use in equalization of said simulcast signal.