Signal Preprocessing Filter for Indoor Wireless Communication
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Solution Overview
Problem
Existing signal transmission methods in indoor environments with frequency selective channels suffer from inter-symbol interference (ISI), leading to performance degradation and increased complexity in receiving apparatuses, making them bulky and power-hungry, which complicates portability and usage.
Innovation Solution
A method and apparatus that preprocess signals using a signal power to sidelobe power ratio (SSR) parameter to minimize ISI, employing an improved time reversal (ITR) filter with weighted coefficients to maximize signal strength and reduce sidelobe interference, thereby simplifying the receiving apparatus and enhancing robustness against noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If code division multiple access scheme is used to solve inter-symbol interference, then inter-symbol interference is reduced, but receiving apparatus complexity increases
Solution Approach 1:
The transmitting apparatus performs preliminary processing on the signal before transmission by convolving it with a predetermined filter to pre-equalize the channel effects. This preliminary action compensates for the frequency selective fading and reduces inter-symbol interference at the receiver, eliminating the need for complex receiving apparatus while maintaining communication reliability.
2Reliability
If zero-forcing technique is used to set inter-symbol interference to 0, then interference is eliminated, but signal strength is reduced
Solution Approach 1:
The patent optimizes the filter coefficients by adjusting parameters to maximize the signal power to sidelobe power ratio (SSR). This parameter optimization allows the filter to suppress inter-symbol interference while preserving signal strength, resolving the contradiction between interference elimination and signal strength maintenance.
3Object-generated harmful factors
If time reversal technique is used to concentrate signals on spatial axis, then multi user interference is reduced, but inter-symbol interference and performance degradation occur
Solution Approach 1:
The patent designs a frequency selective filter with specific local characteristics that address the frequency selective fading effects at different frequency components. The filter coefficients are optimized to handle the local frequency-dependent channel characteristics, thereby reducing both multi-user interference and inter-symbol interference simultaneously without performance degradation.
Data Source
AI summary
Provided are a method and an apparatus for transmitting a signal suitable for an indoor environment. The method for transmitting a signal according to an exemplary embodiment of the present invention includes: preprocessing a signal using a signal power to sidelobe power ratio (SSR) parameter defining a signal to sidelobe ratio to minimize an inter-symbol interference and prevent performance deterioration due to reduction in signal strength; and transmitting the preprocessed signal to a receiving apparatus through a predetermined channel.