Secondary Radio System Pilot Symbols for AIS Channel Estimation
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Solution Overview
Problem
The existing AIS radio communication system lacks reliable channel estimation, particularly in the AIS standard, which impairs decoding capability due to rapid changes in the transmission channel, making it difficult to accurately receive and decode communication data, especially in scenarios with signal collisions.
Innovation Solution
A method that uses a second radio communication system to transmit pilot symbols on different frequencies within the coherence bandwidth of the first radio communication system's frequencies for channel estimation, allowing for improved channel estimation without modifying the original transmission standard.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the AIS standard uses a training sequence at the beginning of each timeslot signal for channel estimation, then the system maintains compatibility with the existing AIS communication protocol, but the rapid changes in the transmission channel make the channel estimation insufficient and unreliable
Solution Approach 1:
The patent introduces a second radio communication system as an intermediary to transmit pilot symbols that serve as channel estimation references for the first AIS system. This mediator system provides reliable channel estimation information without requiring modifications to the original AIS standard, thereby improving channel estimation reliability while maintaining system compatibility.
Solution Approach 2:
The second radio communication system transmits pilot symbols in advance or simultaneously with the AIS data transmission. These pre-transmitted pilot symbols provide the receiver with reference information needed for accurate channel estimation before the actual data reception, enabling reliable equalization despite rapid channel changes.
2Measurement precision
If a second radio communication system transmits pilot symbols on different frequencies within the coherence bandwidth, then accurate channel estimation is enabled, but the system complexity increases due to the need for dual communication systems
Solution Approach 1:
The second radio communication system performs multiple functions: it transmits both data and dedicated pilot symbols for channel estimation. The pilot symbols are specifically designed to enable accurate channel estimation for the first AIS system, while the same infrastructure can be used for other communication purposes, thereby reducing overall system complexity.
Solution Approach 2:
The patent utilizes frequency diversity by transmitting pilot symbols on different frequencies within the coherence bandwidth of the AIS transmission frequency. This parameter change in the frequency domain allows the receiver to obtain multiple channel estimates and select or combine them to achieve accurate channel estimation, improving measurement precision without requiring additional spatial or temporal resources.
3Ease of operation
If the AIS system operates without modifying the original transmission standard, then compatibility and ease of operation are maintained, but decoding capability is impaired due to insufficient channel estimation
Solution Approach 1:
The second radio communication system acts as an intermediary that provides channel estimation references (pilot symbols) to the AIS receiver without requiring any modification to the AIS transmission standard. This allows the AIS system to maintain full compatibility and ease of operation while the mediator enables reliable decoding by supplying the necessary channel state information.
Solution Approach 2:
The patent separates the channel estimation function from the data transmission function by using a dedicated second communication system for pilot symbol transmission. This segmentation allows the AIS system to focus on data transmission while the second system handles channel estimation, thereby maintaining AIS compatibility while improving decoding capability through specialized channel estimation resources.
Data Source
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AI summary
- Transmitting the communication data by means of the first radio communication system from at least one first transmitting unit to at least one first receiving unit, wherein the first radio communication system is assigned one or more first transmission frequencies, and - Transmitting at least one pilot symbol by means of a second radio communication system different from the first radio communication system from a second transmitting unit to at least one second receiving unit, wherein the second radio communication system is assigned one or more second transmission frequencies that are different from the first transmission frequencies of the first communication system, - wherein the pilot symbol was transmitted within the coherence bandwidth of the communication data, - Performing a channel estimation of the transmission channel as a function of the received pilot symbol by means of an evaluation unit to support the decoding function.