OTFS Multi-User Reception Using Joint Equalization Feedback
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Solution Overview
Problem
Current wireless communication networks face bandwidth constraints and challenges in effectively multiplexing orthogonal time frequency space (OTFS) signals for multiple user devices, leading to inefficiencies in data transmission and reception.
Innovation Solution
The implementation of multi-user multiplexing techniques in the delay-Doppler and time-frequency domains, utilizing OTFS transforms and OFDM modulation, along with reference signals for channel estimation and iterative receivers, to manage simultaneous transmissions and receptions from multiple user devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional wireless communication methods are used, then current network infrastructure can be maintained, but bandwidth capacity is insufficient to accommodate explosive growth in wireless data traffic
Solution Approach 1:
The patent introduces a delay-Doppler domain as an additional dimension for resource allocation beyond the traditional time-frequency domain. By transforming resources into a two-dimensional delay-Doppler grid and using OTFS modulation, the system creates new degrees of freedom for multiplexing multiple user devices, effectively increasing bandwidth capacity to handle explosive data traffic growth.
2Adaptability or versatility
If transmission resources are allocated to multiple user devices using traditional methods, then resource allocation can be performed, but signal interference and decoding complexity increase
Solution Approach 1:
The patent transforms the resource allocation from traditional time-frequency domains to a delay-Doppler domain, creating a two-dimensional grid structure. This dimensional transformation enables orthogonal multiplexing of multiple user devices in delay and Doppler dimensions, reducing signal interference and simplifying decoding complexity through the orthogonality properties of OTFS modulation.
3Quantity of substance
If orthogonal time frequency space transformation is applied to multiplex multiple user signals, then bandwidth capacity and signal quality improve, but processing complexity at transmitter and receiver increases
Solution Approach 1:
The patent applies OTFS transformation and delay-Doppler grid allocation as preliminary actions at the transmitter before signal transmission. By pre-organizing resources in the delay-Doppler domain and establishing orthogonal multiplexing structures in advance, the system improves bandwidth capacity and signal quality while managing processing complexity through structured preprocessing rather than complex real-time processing at the receiver.
Data Source
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AI summary
A method, implemented at a receiving device, for receiving an orthogonal time frequency space (OTFS) signal comprising a multiplex of transmissions from multiple transmitting devices is described. The method includes performing joint equalization on the multiplex to generate jointly equalized symbols, extracting, from the jointly equalized symbols, symbols corresponding to a given transmitting device based on extrinsic information about transmission resource location of the symbols, demapping the extracted symbols and performing forward error correction to generate output bits and generating a feedback signal based on the output bits for improving the joint equalization in a next iteration.