Low-complexity Diversity Reception via Frequency Domain Combining
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional antenna diversity systems require full receiver and baseband signal paths for each antenna, leading to high complexity, cost, and power consumption, and may not provide sufficient diversity gain in channels with frequency-selective fading.
Innovation Solution
A wireless diversity receiver with multiple signal processing paths, including a bin-wise combiner and inverse transformation module, that downconverts RF signals, transforms them into subbands, combines these subbands, and performs inverse transformation to generate a time-domain signal, allowing for reduced complexity and enhanced diversity gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional antenna diversity systems use one receiver path for each antenna, then diversity gain is achieved, but device complexity and power consumption increase significantly
Solution Approach 1:
The patent combines multiple antenna receiver paths by merging their frequency domain representations after individual FFT processing. Instead of maintaining separate baseband processing paths for each antenna, the system transforms each antenna's time-domain signal to frequency domain, combines the spectral representations, and then performs a single inverse FFT to reconstruct the combined time-domain signal. This merging approach achieves diversity gain while significantly reducing the complexity of duplicate signal processing hardware.
Solution Approach 2:
The patent segments the receiver processing into distinct stages: individual antenna front-end processing, separate FFT operations for each antenna, frequency domain combining, and a final inverse FFT. This segmentation allows each antenna to be processed independently through efficient FFT algorithms rather than requiring complete duplicate baseband processing paths, reducing overall system complexity while maintaining diversity benefits.
2Reliability
If full receiver and baseband signal paths are provided for each antenna, then signal quality is optimized, but power consumption increases
Solution Approach 1:
The patent merges the power-consuming baseband processing operations by performing FFT on each antenna separately but then combining the frequency domain representations before a single inverse FFT operation. This approach maintains the signal quality optimization benefits of full processing paths while eliminating the redundant power consumption associated with duplicate inverse FFT and baseband processing for each antenna.
Solution Approach 2:
The patent replaces the traditional time-domain signal processing mechanism with frequency-domain processing using FFT algorithms. This substitution enables more efficient computation and combining of multiple antenna signals, as frequency domain operations allow for simpler combining mathematics (element-wise multiplication and addition) compared to time-domain convolution operations, thereby reducing computational power requirements.
3Reliability
If frequency domain combining is performed with bin-wise combiner, then diversity gain is enhanced in frequency-selective fading channels, but processing complexity increases
Solution Approach 1:
The patent segments the frequency spectrum into discrete frequency bins through FFT processing, allowing independent combining operations on each bin. This segmentation transforms the complex problem of frequency-selective fading compensation into simpler per-bin operations where the channel effects are already separated into individual frequency components, making the combining process more manageable despite the increased processing requirements.
Solution Approach 2:
The patent changes the processing domain from time domain to frequency domain, enabling bin-wise combining operations that are specifically effective for frequency-selective fading channels. By transforming the signals through FFT, the system exploits the frequency domain representation where fading effects manifest as independent multiplicative factors on each frequency bin, allowing for more effective diversity combining tailored to the channel characteristics.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves performance comparable to conventional diversity receivers with reduced complexity and power consumption, offering scalable trade-offs between performance and complexity, and can be applied to various wireless standards.
Implementation Method 1
a mixer adapted to downconvert a frequency of an RF signal received by that path
Data Source
AI summary
A system may comprise a plurality of signal processing paths, a bin-wise combiner, an inverse transformation block, and a DAC. Each signal processing path may comprise a transformation block that is operable to transform a first time-domain digital signal to an associated frequency-domain signal having a plurality of subband signals. The bin-wise combiner may be operable to combine corresponding subband signals of the plurality of signal processing paths. The inverse transformation block may be operable to transform output of the bin-wise combiner to an second time-domain signal. The DAC may be operable to converts the second time-domain signal to a corresponding analog signal.