Multiuser Downlink NOMA Transmission Without Large Matrix Libraries
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Solution Overview
Problem
Current wireless communication systems face challenges in achieving high throughput and efficient concurrent transmission of downlink data streams due to limitations in non-orthogonal multiple access (NOMA) schemes like RA-CEMA, which require large multiplexing matrix libraries and sequential modulation and coding scheme (MCS) computations, leading to increased memory footprint and signaling overhead.
Innovation Solution
A transmitter device that determines downlink channel quality, computes scheduler weights, and performs joint user selection and multiplexing parameter optimization to enhance throughput by using a multiplexing matrix and code rates, reducing the need for large matrix libraries and overhead signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If non-orthogonal multiple access (NOMA) schemes like RA-CEMA are used for concurrent transmission, then throughput is improved, but memory footprint and signaling overhead increase due to large multiplexing matrix libraries
Solution Approach 1:
The patent extracts and removes the large multiplexing matrix library from the system, replacing it with a streamlined approach that computes multiplexing parameters on-demand based on channel conditions. This eliminates the need for storing extensive pre-computed matrices while maintaining the concurrent transmission capability.
Solution Approach 2:
The system performs preliminary computation of channel qualities and scheduler weights before determining the multiplexing parameters. By pre-calculating these channel-dependent parameters, the system avoids the need for large stored matrix libraries, as the multiplexing configuration is derived dynamically from current channel conditions rather than selected from pre-stored options.
2Productivity
If non-orthogonal multiple access (NOMA) schemes like RA-CEMA are used for concurrent transmission, then throughput is improved, but signaling overhead increases
Solution Approach 1:
The patent removes the extensive signaling required to convey multiplexing matrix selection information. Instead of signaling which pre-stored matrix to use, the system signals only the essential channel-dependent parameters (channel qualities and scheduler weights), from which receivers can independently derive the multiplexing configuration, dramatically reducing signaling overhead.
Solution Approach 2:
The receiver devices are enabled to self-determine the multiplexing parameters by computing channel qualities and using the signaled scheduler weights. This self-service approach eliminates the need for the transmitter to signal detailed multiplexing matrix information, as each receiver independently configures its demultiplexing based on its own channel conditions.
3Device complexity
If sequential modulation and coding scheme (MCS) computations are performed, then device complexity is reduced, but productivity decreases
Solution Approach 1:
The patent merges the modulation selection and coding scheme computation into a unified, joint optimization process. Instead of sequentially determining MCS parameters, the system simultaneously optimizes modulation order, code rate, and multiplexing parameters based on channel qualities and scheduler weights, achieving higher throughput while maintaining computational efficiency through integrated decision-making.
Data Source
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AI summary
A data transmission and signaling method in a transmitter device configured for concurrent transmission of non-orthogonal independent downlink data streams to receiver devices in a wireless communication system comprises sending to all receiver devices control information that includes indices of receiver devices selected for transmission, code rates of selected receiver devices, a label bit-to-receiver device allocation, an index of an expanded constellation, and a number of resource elements used for transmission.