Semi-Orthogonal Multiple Access in WLANs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wireless local area networks (WLANs) face challenges in optimizing data transmission efficiency across stations with varying signal-to-noise ratios, as existing technologies like NOMA require one station to decode signals intended for another, leading to decoding performance degradation and increased processing complexity.
Innovation Solution
The implementation of semi-orthogonal multiple access (SOMA) in WLANs, where a transmitting device determines QAM bit allocations and coding rates for each receiving device based on channel information, allowing for independent decoding without interference, using power and modulation domain multiple access (PMDMA) to improve channel capacity and provide unequal protection to data for different stations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If non-orthogonal multiple access (NOMA) is used to increase channel capacity, then more users can be served simultaneously, but decoding performance degrades and processing complexity increases
Solution Approach 1:
The patent segments the QAM constellation into multiple independent subsets, each assigned to a specific receiving device. This segmentation allows each device to decode only its assigned subset without needing to decode other devices' signals, thereby reducing processing complexity while maintaining high channel capacity. The transmitting device divides the modulation symbols into separate groups that can be independently processed by different receivers.
Solution Approach 2:
The patent applies local quality by assigning different QAM bit allocations and coding rates to different receiving devices based on their specific channel conditions. Each device receives a customized transmission optimized for its signal-to-noise ratio, improving decoding performance while allowing simultaneous service to multiple users with varying channel qualities.
2Productivity
If NOMA is used to serve multiple users simultaneously, then spectral efficiency improves, but one station must decode signals intended for another leading to performance degradation
Solution Approach 1:
The patent segments the transmitted signal into distinct QAM subsets that are orthogonally separable at the receiver. Each receiving device is assigned a specific subset of QAM bits that it can decode independently without being affected by signals intended for other devices, thereby eliminating the interference problem inherent in traditional NOMA while maintaining spectral efficiency.
Solution Approach 2:
The patent introduces an intermediary structure in the form of semi-orthogonal QAM constellations that mediate between multiple users. These constellations are designed such that signals for different users are embedded in orthogonal subspaces, allowing simultaneous transmission without mutual interference. The intermediary structure enables each user to decode its signal independently as if it were the only user present.
3Device complexity
If uniform QAM bit allocation is used for all receiving devices, then system complexity is reduced, but channel capacity optimization is limited
Solution Approach 1:
The patent implements local quality by determining different QAM bit allocations for different receiving devices based on their individual channel conditions. The transmitting device assesses the signal-to-noise ratio of each receiver and assigns appropriate QAM constellations and bit allocations optimized for each device's specific channel quality, thereby maximizing overall channel capacity while maintaining manageable system complexity through automated allocation rules.
Data Source
AI summary
A method for operating a transmitting device using semi-orthogonal multiple access (SOMA) in a wireless local area network (WLAN) includes determining a first quadrature amplitude modulation (QAM) bit allocation, a first coding rate, and a first SOMA group for a first receiving device and a second QAM bit allocation, a second coding rate, and a second SOMA group for a second receiving device in accordance with channel information associated with the first receiving device and the second receiving device, generating a frame including indicators of the first and second QAM bit allocations, the first and second coding rates, and the first and second SOMA groups, and sending the frame to the first receiving device and the second receiving device.