Multi-layer RSMA with Permutation and Phase Rotation
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Solution Overview
Problem
Current wireless communication systems face challenges in achieving efficient multiplexing and reducing signaling overhead in non-orthogonal multiple access (NOMA) systems, particularly in uplink transmissions, where inter-UE interference and complexity in advanced receivers hinder spectral efficiency and quality of service requirements.
Innovation Solution
A multi-layer resource spread multiple access (RSMA) scheme is implemented, where a stream of bits is demultiplexed into layers with different coding rates, modulated using various schemes, spread and scrambled with unique codes, permuted, scaled, and phase-rotated, and then summed and mapped onto shared resources, enabling improved spectral efficiency and simplified interference cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple UEs share the same radio resources in NOMA system, then multiplexing efficiency is improved, but inter-UE interference increases and receiver complexity increases
Solution Approach 1:
The patent segments the transmitted signal into multiple layers with different coding rates and modulation schemes. Each layer is independently encoded and modulated, allowing the receiver to process and cancel interference from stronger layers before decoding weaker layers, thereby reducing overall receiver complexity while maintaining high multiplexing efficiency
Solution Approach 2:
The patent applies different coding rates and modulation schemes to different layers, creating intentional parameter variations. This allows the receiver to exploit these differences in signal characteristics to perform successive interference cancellation more effectively, reducing the complexity of handling inter-UE interference
2Productivity
If different coding rates and modulation schemes are applied to different layers, then spectral efficiency is improved, but processing complexity increases
Solution Approach 1:
The transmission is divided into multiple layers, each with independently optimized coding rates and modulation schemes. This segmentation allows spectral efficiency to be maximized for each layer's channel conditions while the modular structure keeps processing complexity manageable through systematic encoding and modulation operations
Solution Approach 2:
The patent dynamically assigns different coding rates and modulation schemes to different layers based on channel conditions and QoS requirements. This dynamic parameter adjustment enables spectral efficiency optimization without permanently increasing processing complexity, as the same processing pipeline handles variable parameters
3Ease of operation
If spreading codes and scrambling codes are used to separate UEs, then interference cancellation is simplified, but signaling overhead increases
Solution Approach 1:
The patent uses spreading codes and scrambling codes that are systematically generated and known to both transmitter and receiver. These codes act as reusable templates that simplify interference cancellation through correlation operations, while their structured nature reduces the need for extensive signaling about code assignments
Data Source
AI summary
Aspects of the disclosure relate to methods and an apparatus for transmitting a signal in a multi-layer hybrid resource spread multiple access (RSMA) system. A non-orthogonal multiple access (NOMA) user equipment (UE) demultiplexes a stream of bits into a plurality of layers, encodes each layer with a different coding rate, modulates each layer of encoded bits with a different modulation scheme, and spreads and scrambles each layer of modulated symbols with a different spreading code and a corresponding different scrambling code. Thereafter, the NOMA UE permutes the plurality of layers having spread and scrambled symbols into a plurality of interleaved layers, scales and phase rotates each interleaved layer with a different scaling factor and a corresponding different phase rotating factor, sums the scaled and phase rotated symbols, maps the summed symbols onto a set of allocated resources, and transmits the mapped symbols via the set of resources.