Interleaved DFT Block Multiplexing Without Pilot Overhead
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Solution Overview
Problem
Current multi-user access schemes in wireless communication, particularly in LTE and 5G networks, face challenges with high mobility and large numbers of devices, leading to increased pilot contamination and overhead due to channel estimation, especially in scenarios with fast time-varying links and high user mobility.
Innovation Solution
The implementation of multi-user frequency-division multiplexing for block transmissions using discrete Fourier transform (DFT) operations, interleaving, and time shifting to separate user signals in the frequency domain, allowing for efficient resource allocation and reduced peak-to-average power ratio (PAPR) without the need for pilot signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coherent signaling schemes are used for multi-user access, then communication reliability is improved, but pilot overhead increases due to channel estimation requirements
Solution Approach 1:
The patent extracts the channel estimation function from the traditional coherent signaling scheme by using non-coherent detection. Instead of requiring separate pilot signals for channel estimation, the system processes received signals directly without explicit channel knowledge, thereby removing the pilot overhead component while maintaining communication reliability through alternative signal processing techniques.
Solution Approach 2:
The patent segments the multi-user signal into distinct user-specific components that can be processed independently through non-coherent detection. By dividing the received signal into individual user signal paths and applying separate non-coherent detection to each, the system eliminates the need for unified pilot sequences while maintaining reliable user-specific communication.
2Measurement precision
If pilot signals are used for channel estimation, then channel knowledge is improved, but spectral efficiency deteriorates due to resource overhead
Solution Approach 1:
The patent removes the pilot signal component entirely from the system by implementing non-coherent detection. The channel knowledge function is extracted and replaced by signal processing techniques that do not require explicit channel estimation, thereby eliminating the spectral resources dedicated to pilot transmission and improving overall spectral efficiency.
Solution Approach 2:
The system performs self-service by using the transmitted signal itself for detection purposes without requiring separate pilot signals. The non-coherent detection process utilizes the signal structure and properties directly, allowing the system to obtain necessary information for reliable communication without external pilot assistance, thus improving spectral efficiency.
3Area of stationary object
If users are served in high-mobility scenarios, then network coverage is improved, but pilot contamination increases due to fast time-varying links
Solution Approach 1:
The patent extracts the vulnerability to pilot contamination by removing the pilot-based channel estimation mechanism. In high-mobility scenarios where channel conditions change rapidly, the system uses non-coherent detection that does not rely on stable pilot signals, thereby eliminating pilot contamination effects while maintaining network coverage for mobile users.
Solution Approach 2:
The patent adapts to dynamic high-mobility conditions by using non-coherent detection that does not assume static or slowly varying channel conditions. The system dynamically processes signals without requiring channel stability, allowing it to serve users in high-mobility scenarios effectively without suffering from pilot contamination that plagues traditional coherent schemes.
Data Source
AI summary
A computer-implemented method for multi-user multiplexing for block transmissions by an electronic device includes generating a user signal that includes a number of first samples in the time domain. The number of first samples are generated based on a discrete-time baseband signal and a predetermined guard period. A discrete Fourier transform (DFT) operation is performed on the number of first samples to obtain a number of second samples in the frequency domain. An interleaving operation is performed on the number of second samples to obtain a number of third samples in the frequency domain. An inverse-DFT (IDFT) operation is performed on the number of third samples to obtain a number of fourth samples in the time domain. A time shifting is performed on the number of fourth samples to obtain a number of shifted fourth samples. A block transmission is sent using the number of shifted fourth samples.