Wireless Transmitter Channel Distortion Compensation
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Solution Overview
Problem
Current wireless communication systems face challenges in managing signal fading and interference due to unpredictable channel responses, particularly in urban environments where signals are distorted by reflections off buildings and moving vehicles, leading to non-deterministic signal distortion and fading.
Innovation Solution
The system employs novel modulation techniques that transmit data in short bursts, modulated with time and frequency shifts to expose the underlying structure of the communication channel, allowing for intelligent correction of distortions by characterizing the channel response parameters using pilot symbols and error codes, and utilizing multiple antennas for beam forming and polarization to improve signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional wireless communication signals are transmitted, then data transmission occurs, but signal fading and distortion occur due to reflections and Doppler shifts in the communication channel
Solution Approach 1:
The patent segments the data transmission into multiple short bursts transmitted at different times, each burst containing a portion of the total data. This segmentation allows the system to transmit information multiple times through different channel realizations, enabling the receiver to combine these segments and achieve reliable data recovery despite fading and distortion in any single transmission.
Solution Approach 2:
The patent employs pilot symbols transmitted before the actual data bursts to characterize the communication channel response. These preliminary pilot signals allow the receiver to estimate channel parameters including time delay, Doppler shift, and fading characteristics, enabling subsequent deconvolution and equalization of the data bursts to compensate for signal distortion.
2Productivity
If signals are transmitted through the communication channel, then data communication is achieved, but echo signals and frequency shifts occur due to reflections and moving reflectors
Solution Approach 1:
By dividing the data into multiple short bursts transmitted at different times, the patent reduces the impact of echo signals and frequency shifts. Each short burst experiences a relatively stable channel condition, and the receiver can combine these segments after deconvolution, maintaining high data transmission rates while mitigating the harmful effects of reflections and Doppler shifts.
Solution Approach 2:
The patent uses pilot symbols to obtain feedback about the channel state, including echo and frequency shift characteristics. This channel state information is fed back to the receiver, which then uses it to perform deconvolution and equalization, effectively compensating for echo signals and frequency shifts while maintaining high productivity.
3Reliability
If statistical methods are used to manage signal fading, then communication can proceed, but signal efficiency decreases and data transmission rates are reduced
Solution Approach 1:
The patent replaces statistical methods with deterministic signal processing techniques. Instead of relying on statistical averaging and probability-based error correction, the system uses pilot symbols to deterministically characterize the channel and applies deconvolution algorithms to exactly compensate for fading and distortion, thereby maintaining both reliability and high data transmission rates.
Solution Approach 2:
The patent changes the approach from statistical parameter estimation to precise channel parameter measurement using pilot symbols. By transmitting known pilot signals and measuring the actual channel response, the system obtains accurate parameters for time delay, Doppler shift, and fading characteristics, which are then used to adjust the signal parameters for optimal transmission, improving both reliability and productivity.
Data Source
AI summary
Computerized wireless transmitter/receiver system that automatically uses combinations of various methods, including transmitting data symbols by weighing or modulating a family of time shifted and frequency shifted waveforms bursts, pilot symbol methods, error detection methods, MIMO methods, and other methods, to automatically determine the structure of a data channel, and automatically compensate for signal distortions caused by various structural aspects of the data channel, as well as changes in channel structure. Often the data channel is a two or three dimensional space in which various wireless transmitters, receivers and signal reflectors are moving. The invention's modulation methods detect locations and speeds of various reflectors and other channel impairments. Error detection schemes, variation of modulation methods, and MIMO techniques further detect and compensate for impairments. The invention can automatically optimize its operational parameters, and produce a deterministic non-fading signal in environments in which other methods would likely degrade.