Envelope Combining for On-Off Keying Signal Reception
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Solution Overview
Problem
Wireless sensor networks face challenges in achieving reliable communication due to limited receiving performance and short communication distances, particularly in low-power and low-complexity environments such as wireless body area networks, where existing reception diversity technologies are not effectively suited for non-coherent on-off keying modulation schemes.
Innovation Solution
An apparatus and method utilizing multiple antennas to receive on-off keying modulated signals, involving a detector to identify signal envelopes, a combiner for linear and nonlinear processing of these envelopes, and a message determining unit to estimate transmission bits by comparing combined signals with thresholds based on channel status and system parameters, optimizing thresholds using Rayleigh and Rician probability density functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple antennas are used for signal reception, then signal-to-noise ratio gain and diversity gain are improved, but device complexity increases
Solution Approach 1:
The patent combines signals from multiple antennas through a combiner that performs linear and nonlinear processing on detected envelopes. The combiner merges the K detected envelopes using techniques such as square-law combining or logarithmic combining, achieving signal-to-noise ratio gain and diversity gain while maintaining a unified processing structure that manages complexity.
Solution Approach 2:
The patent extracts the envelope information from each received signal using detectors before combining. By taking out only the envelope magnitude information and discarding phase information, the system simplifies the processing required for multiple antennas while still achieving diversity gain through envelope combining.
2Length of stationary object
If envelope detection and combining processing are performed, then communication distance is extended, but processing complexity increases
Solution Approach 1:
The patent replaces complex phase-coherent processing with envelope detection and nonlinear combining. Instead of performing complex correlation and phase synchronization operations, the system uses envelope detectors followed by nonlinear combining operations (squaring, logarithmic processing), which are computationally simpler while achieving extended communication distance through diversity gain.
3Reliability
If linear and nonlinear processing are applied to detected envelopes, then bit error rate is reduced, but computational complexity increases
Solution Approach 1:
The patent applies parameter transformations to the detected envelopes, including squaring operations and logarithmic transformations. These parameter changes convert the distributed envelope values into a form that, when combined, provides optimal bit error rate performance for on-off keying modulation while keeping the computational operations relatively simple.
Data Source
AI summary
Provided are an apparatus and method for acquiring a signal to noise ratio (SNR) gain and a diversity gain using multiple antennas for receiving data, and an apparatus for receiving a signal using multiple antennas. The apparatus may receive on-off keying modulated signals through K receiving antennas, detect envelopes with respect to each of the signals received through the K receiving antennas, combine signals generated by performing a linear processing and a nonlinear processing with respect to each of the K detected envelopes, and determine a message value of the on-off keying modulated signals.