Grassmannian Constellation Mapping for Non-Coherent Decoding
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Solution Overview
Problem
Conventional non-coherent communication schemes face high decoding complexity and low spectral efficiency, and conventional non-coherent communication schemes based on Differential Phase Shift Keying exhibit low spectral efficiency.
Innovation Solution
A transmitter communication apparatus and receiver communication apparatus implement a non-coherent communication scheme using a modulation constellation defined by a tiling of a Grassmannian manifold and a Cartesian product of auxiliary constellations, with data bits mapped into modulation symbols to ensure uniform distribution and phase relationships, enabling efficient decoding without channel estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional non-coherent communication schemes use unstructured constellations, then decoding complexity is reduced, but spectral efficiency becomes low
Solution Approach 1:
The modulation constellation is segmented into multiple cells through tiling of the Grassmannian manifold. Each cell contains a structured subset of modulation symbols with specific geometric properties. This segmentation allows the receiver to perform decoding within smaller, manageable cell regions rather than searching the entire constellation space, reducing complexity while maintaining high spectral efficiency through the structured arrangement of symbols within each cell.
Solution Approach 2:
The patent transitions from conventional two-dimensional constellations to high-dimensional Grassmannian manifold constellations. By mapping modulation symbols onto the Grassmannian manifold (a space of dimension greater than 2), the system achieves more efficient packing of constellation points, increasing spectral efficiency. The structured tiling of this high-dimensional space enables low-complexity decoding through exploitation of the manifold's geometric properties.
2Ease of manufacture
If conventional non-coherent communication schemes use DPSK, then implementation is simplified, but spectral efficiency becomes low
Solution Approach 1:
The patent changes the fundamental parameter space from conventional phase-only modulation (DPSK) to Grassmannian manifold coordinates. By representing modulation symbols as points on the Grassmannian manifold with specific geometric relationships, the system achieves higher spectral efficiency. The structured tiling provides clear geometric rules for symbol generation and detection, maintaining implementation simplicity while dramatically improving the number of information bits transmitted per channel use.
3Measurement precision
If coherent communication schemes use pilot sequences for channel estimation, then communication accuracy is improved, but spectral resources are consumed
Solution Approach 1:
The patent extracts and removes the need for pilot sequences entirely from the communication system. By using non-coherent detection based on Grassmannian manifold geometry, the system achieves reliable communication without requiring channel state information. This eliminates the spectral resources that would otherwise be consumed by pilot sequences while maintaining communication accuracy through the geometric structure of the modulation constellation.
Solution Approach 2:
The Grassmannian manifold-based modulation scheme is self-sufficient and does not require external channel estimation assistance. The structured constellation and its geometric properties enable the receiver to directly detect modulation symbols without needing to estimate channel characteristics. This self-service capability eliminates dependency on pilot sequences and achieves spectral efficiency by using all available resources for data transmission.
Data Source
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AI summary
The invention relates to a transmitter communication apparatus (101 a) and a receiver communication apparatus (103) of a non-coherent communication system (100). The transmitter communication apparatus (101 a) is configured to communicate with the receiver communication apparatus (103) via a communication channel. The transmitter communication apparatus (101 a) comprises a processing circuitry configured to: map a sequence of data bits into a modulation symbol of a plurality of modulation symbols defined by a modulation constellation, wherein the modulation constellation is defined by a tiling of a manifold, in particular a Grassmannian manifold into a plurality of cells and a Cartesian product of a plurality of auxiliary constellations, wherein the Cartesian product of the plurality of auxiliary constellations is mapped onto each cell of the plurality of cells and wherein each auxiliary constellation defines a plurality of auxiliary symbols; and transmit a modulated signal based on the modulation symbol via the communication channel to the receiver communication apparatus (103).