Multi-Access Uplink Transmission for Different Waveforms Without Guard Bins
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Solution Overview
Problem
Existing multi-access schemes for Orthogonal Time Frequency Space (OTFS) waveforms in uplink transmission for multiple users require generating entire frames irrespective of resource allocation, leading to increased complexity and inefficiency, and existing methods do not effectively support multi-user scenarios without guard bins or require excessive antenna resources.
Innovation Solution
A method and apparatus for multi-access uplink transmission that allocates indices for modulated symbols, transforms them using specific matrices based on waveform type, upsamples with stuffed zeros, and circularly shifts symbols, allowing simultaneous transmission of different waveforms without generating entire frames, thereby reducing complexity and eliminating the need for guard bins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If users generate entire OTFS frames for transmission, then multi-access can be achieved, but signal processing complexity increases significantly
Solution Approach 1:
The patent segments the OTFS frame into smaller resource blocks and further into individual symbols, allowing users to transmit only the allocated portions rather than generating complete frames. This segmentation reduces the processing burden on user devices while maintaining multi-access functionality through coordinated resource block allocation.
Solution Approach 2:
Instead of requiring users to generate entire frames (excessive action), the patent enables users to transmit only the partial frames corresponding to their allocated resource blocks. This partial transmission approach reduces complexity while the base station handles the complete frame reconstruction through coordinated processing of partial signals from multiple users.
2Reliability
If guard delay bins are used for multi-access, then user interference is reduced, but spectral efficiency decreases
Solution Approach 1:
The patent merges the transmission of multiple users within the same time-frequency resources by using different spreading codes or modulation schemes for each user. This combining approach eliminates the need for guard bins while maintaining user separation through the base station's processing capabilities, thereby preserving spectral efficiency without sacrificing reliability.
3Reliability
If users transmit with high power to ensure reliability, then signal quality improves, but peak power consumption increases
Solution Approach 1:
The patent employs variable power transmission where users adjust their transmission power levels based on channel conditions and allocation requirements rather than using constant high power. This parameter adaptation allows reliable communication while controlling peak power consumption, especially when combined with the frame segmentation approach that reduces the total energy burden on user devices.
Data Source
AI summary
Provided is a multi-access method (500, 600) and a communication apparatus (102) for uplink transmission of different waveforms. The method (500) comprises receiving (502) an allocation of one or more indices for a respective users for uplink transmission of modulated symbols. The method further comprising transforming (504) the modulated symbols using a first matrix (P) for each index among the one or more indices. Furthermore, the method comprises generating (506) discrete-time signals by upsampling by a factor of plurality of indices by stuffing one or more zeroes, and circularly shifting the upsampled symbols. The method further comprises transmitting (508) uplink signals by combining the generated discrete-time signals of each user for the allocated one or more indices.