Multi-Correlator Radio Receiver for Frequency-Offset Signal Detection
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Solution Overview
Problem
Existing digital radio transmission systems face challenges in balancing power consumption and transmission range, as signals become susceptible to noise and bit errors, especially in long-range communications, and current methods to improve signal quality, such as increasing transmission power, are inconsistent with reducing power consumption.
Innovation Solution
A digital radio receiver using a plurality of correlators, each corresponding to a different bit sequence, sharing a common estimator to estimate frequency offset and determine the desired output signal, which enhances sensitivity and tolerance to noise, allowing for low-energy, long-range transmissions by representing each bit as a sequence of chips and using a common estimator for both despreading and synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transmission power is increased to improve signal-to-noise ratio and extend communication range, then transmission quality is improved, but power consumption increases
Solution Approach 1:
The invention segments the correlation process into multiple parallel correlators, each handling different bit sequence hypotheses. This allows the receiver to process multiple possibilities simultaneously without increasing transmission power, thereby maintaining transmission quality while avoiding additional power consumption at the transmitter side.
Solution Approach 2:
The invention transitions from a single-correlator sequential approach to a multi-correlator parallel approach, adding the dimension of parallel processing. This enables the system to evaluate multiple bit sequence hypotheses concurrently, improving transmission quality through better signal detection without requiring increased transmission power.
2Reliability
If spread spectrum modulation is used to represent bits as chip sequences to reduce the impact of losing single chips, then transmission robustness is improved, but the system becomes vulnerable to carrier frequency offset and drift
Solution Approach 1:
The invention employs multiple correlators that test different bit sequence hypotheses, performing more correlation operations than the minimum single-correlator approach. This excessive action provides redundancy that compensates for the vulnerability to carrier frequency offset, allowing the system to maintain transmission robustness even when frequency drift occurs.
Solution Approach 2:
The invention changes the parameter being tested by multiple correlators - each correlator is configured with different bit sequence hypotheses. By varying the expected bit patterns across multiple correlators, the system can identify the correct sequence despite carrier frequency offset, thereby maintaining robustness against this harmful factor.
3Device complexity
If a single correlator is used to determine bit patterns, then device complexity is reduced, but the receiver cannot accurately determine bit patterns under low signal-to-noise ratios and carrier frequency offset
Solution Approach 1:
The invention segments the detection function across multiple correlators, with each correlator responsible for testing specific bit sequence hypotheses. This segmentation improves measurement precision by distributing the detection task, allowing accurate bit pattern determination even in challenging conditions with low signal-to-noise ratios and carrier frequency offset.
Solution Approach 2:
The invention combines the outputs of multiple correlators to make the final bit pattern determination. By merging the results from multiple correlation operations, the system achieves high detection accuracy without requiring an overly complex receiver structure, as the correlators share common functionality.
4Measurement precision
If multiple correlators are used to compare bit sequences and determine the desired output signal, then bit pattern determination accuracy is improved under low signal-to-noise ratios, but device complexity increases
Solution Approach 1:
The invention makes each correlator universal by designing them with common functionality - they all perform correlation operations using the same basic structure but with different bit sequence hypotheses. This multi-functionality approach improves measurement precision through parallel comparison while limiting device complexity by reusing the same correlator design across multiple instances.
Data Source
AI summary
A digital radio receiver is adapted to receive radio signals modulated using continuous phase modulation. The receiver includes components for receiving analogue radio signals having various carrier frequencies and a plurality of correlators corresponding to different bit sequences. Each of the plurality of correlators share a common estimator for estimating a frequency offset between the radio signals carrier frequencies and nominal carrier frequencies. The receiver further includes components allowing the estimator to determine which of the correlators produce the most optimal output signal.