Joint Waveform Design for Time-Reversal Interference Pre-Cancellation
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Solution Overview
Problem
High symbol rates in time-reversal communication systems lead to inter-symbol interference (ISI), reducing system performance, and existing technologies struggle to effectively manage ISI and inter-user interference in multi-user scenarios.
Innovation Solution
The implementation of joint waveform design and interference pre-cancellation techniques, where the transmitter uses channel information and symbol information to generate signature waveforms that pre-cancel causal interference and suppress anti-causal interference, leveraging the multipath channel for spatial focusing and reducing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high symbol rates are used for high-speed data transmission, then productivity is improved, but inter-symbol interference increases reducing system performance
Solution Approach 1:
The patent applies preliminary action by performing interference pre-cancellation at the transmitter before signal transmission. The base station calculates and subtracts expected interference components from data symbols based on channel information and signature waveforms, thereby eliminating inter-symbol interference before the signal propagates through the multipath channel. This proactive interference removal enables high symbol rates without performance degradation.
2Reliability
If joint waveform design and interference pre-cancellation are implemented, then inter-symbol interference is reduced improving reliability, but device complexity increases
Solution Approach 1:
The patent employs feedback by utilizing channel information obtained from probe signals transmitted by terminal devices. The base station receives probe signals, estimates channel characteristics, and uses this feedback information to calculate signature waveforms and perform interference pre-cancellation. This feedback mechanism enables adaptive interference suppression tailored to specific channel conditions while maintaining manageable complexity through efficient channel estimation techniques.
3Reliability
If time-reversal techniques are used for spatial focusing, then signal quality is improved, but interference management in multi-user scenarios becomes more difficult
Solution Approach 1:
The patent applies segmentation by separating interference management into distinct components: signature waveform generation for spatial focusing, interference calculation based on segmented channel responses from different users, and pre-cancellation of identified interference components. This segmented approach to handling multi-user signals enables the system to maintain spatial focusing accuracy while managing interference from multiple terminal devices through systematic, modular processing.
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
This approach significantly reduces inter-symbol and inter-user interference, improving the overall performance of the communication system by enhancing signal quality and simplifying receiver complexity, while allowing for high-speed data transmission with low-power consumption.
Implementation Method 1
Transceiver A transmits time-reversed signals back through the same channel to transceiver B. Based on channel reciprocity, a time-reversal communication system leverages the multi-path channel as a matched filter, i.e., treats the environment as a facilitating matched filter computing machine, and focuses the wave at the receiver in both space and time domains.
Implementation Method 2
Based on channel reciprocity, a time-reversal communication system leverages the multi-path channel as a matched filter
Data Source
AI summary
A base station having an input module for receiving a probe signal sent from a terminal device, and a data processor for generating a signature waveform that is based on channel information derived from the probe signal, identifying data symbols intended to be transmitted to the terminal device, and modifying the data symbols based on the channel information. The modification of the data symbols is designed to reduce inter-symbol interference when the data symbols are received by the terminal device. The data processor generates a downlink signal based on the modified data symbols and the signature waveform. The base station generates a wide-band a radio frequency signal based on the downlink signal and transmits the radio frequency signal to the terminal device through a multipath channel such that a portion of the radio frequency signal intended for the terminal device focuses at the terminal device.