Unified Multiple Access Grid for High-Speed Uplink Transmission
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Solution Overview
Problem
Existing multiple access mechanisms, such as OTFS, OTSM, and block single carrier (SC), face challenges in high-speed scenarios with high peak power requirements and complex signal generation, limited time-frequency diversity, and lack of multi-user receiver support.
Innovation Solution
A unified multiple access system that allocates resources directly in the delay-Doppler domain or a virtual delay-Doppler domain, using a sparsely loaded two-dimensional data grid with QAM symbols, ensuring each user transmission spans the entire time-frequency grid, reducing peak power and enabling multi-antenna reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If resources are allocated in time-frequency domain using traditional OFDMA, then resource allocation is simple, but time-frequency diversity is limited and performance degrades in high-speed scenarios
Solution Approach 1:
The patent transforms the traditional one-dimensional time-frequency resource allocation into a two-dimensional delay-Doppler domain allocation. By mapping time-frequency resources to delay-Doppler coordinates, the system achieves better exploitation of time-frequency diversity while maintaining manageable complexity through the structured grid-based allocation approach.
Solution Approach 2:
The patent changes the fundamental parameters of resource allocation from time-frequency coordinates to delay-Doppler coordinates. This parameter transformation enables the system to adapt to high-speed scenarios by capturing Doppler shifts and delay effects directly in the allocation domain, improving reliability without proportionally increasing complexity.
2Reliability
If guard bins are introduced in delay-Doppler domain to support multiple users, then user isolation is improved, but spectral efficiency decreases due to resource waste
Solution Approach 1:
The patent applies local quality by introducing guard bins only at specific locations where user allocations boundary meet, rather than uniformly across the entire delay-Doppler grid. This localized approach provides necessary user isolation at allocation boundaries while minimizing the overall impact on spectral efficiency by keeping guard bins to a minimum.
3Productivity
If dense grid allocation is used to maximize resource utilization, then spectral efficiency is improved, but peak power requirements increase
Solution Approach 1:
The patent extracts and removes the problematic dense allocation pattern from the delay-Doppler grid by introducing strategic null points (zero-power positions) within user allocations. This extraction of dense packing at critical locations reduces peak power requirements while maintaining overall high spectral efficiency through efficient use of the remaining grid points.
Data Source
AI summary
The present invention discloses an unified multiple access (MA) based system for uplink transmission of data by multiple users. The system comprises an user interface integrated transmitter modules for transmitting the data from multiple user transmitters over waveforms through a cooperative unified data grid structure including grid points, said unified data grid structure including each user transmitter allocation of a few non-overlapping grid points for loading respective data bearing symbols, with zeros loaded onto unallocated grid points. The user transmitter is configured to transmit a sparsely loaded grid resembling to the unified two-dimensional data grid structure involving data-bearing Quadrature Amplitude Modulation (QAM), where a part of available grid points of the grid as allocated is loaded with QAM symbols and remaining grid points are loaded with zero symbols. A waveform modulator corresponding to user transmitter is also provided in the present system for waveform modulation of said sparsely loaded grid as per the waveforms enabling transmission for multi-antenna reception of the waveforms to a base station or an access point.