Antenna Diversity Combining for OFDM Signals
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Solution Overview
Problem
Current antenna diversity systems are inefficient in handling digital radio broadcasts, such as HD radio or Digital Audio Broadcasting, due to the complexity of handling multipath fading and frequency-selective fading, which results in increased bit error rates and audio distortion.
Innovation Solution
A multi-tuner system that processes RF signals from multiple antennas to generate time-domain quadrature signals, which are then converted to frequency-domain signals, differentially decoded, and combined to produce a diversity combined signal, reducing the complexity of diversity combining at the demodulator and enabling efficient handling of multipath impairments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If antenna diversity combining is implemented for digital radio broadcasts, then signal quality and data integrity are improved, but device complexity increases due to the need for multiple tuners and processing circuits
Solution Approach 1:
The patent combines multiple tuner circuits and signal processing functions into a single integrated device. Specifically, multiple tuners receive signals from multiple antennas and process them through shared circuits including FFT engines, channel decoders, and combiners. This merging approach achieves diversity combining for improved signal quality while reducing overall device complexity through resource sharing and integration.
Solution Approach 2:
The patent implements multi-functionality by designing tuner circuits and processing elements that can handle both single-antenna and multi-antenna diversity modes. The same tuner and processing circuits are used whether one or multiple antennas are active, allowing the system to adapt to different operating conditions without requiring separate dedicated hardware paths for each mode.
2Reliability
If diversity combining is performed at the demodulator, then signal processing is centralized, but processing delay and complexity increase
Solution Approach 1:
The patent performs preliminary signal processing and diversity combining operations before the final demodulation stage. Specifically, multiple tuners pre-process their received signals through FFT transformation, channel decoding, and combining operations in advance. This preliminary action prepares combined and pre-decoded signals that reduce the processing burden and delay at the final demodulator stage, improving overall processing efficiency while maintaining data integrity.
Data Source
AI summary
In an embodiment, an apparatus includes a first tuner to receive a radio frequency (RF) signal from a first antenna and to process the RF signal to generate a first time-domain quadrature signal, a second tuner to receive the RF signal from a second antenna and to process the RF signal to generate a second time-domain quadrature signal, and a combiner circuit to receive the first and second time-domain quadrature signals.