Quantized NCC for Wireless Multi-User Interference
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Solution Overview
Problem
Current wireless communication systems face challenges in accommodating explosive data traffic, increasing transfer rates, supporting a large number of connected devices, and achieving low end-to-end latency and high energy efficiency, particularly in managing multi-user interference in non-orthogonal multiple access schemes.
Innovation Solution
The proposed method employs a quantized non-orthogonal coded multiple access scheme using a Grassmannian sequence, where each coefficient is quantized using M-quadrature amplitude modulation (QAM) constellation to reduce the number of bits required while maintaining the characteristics of the Grassmannian sequence, allowing for efficient communication by minimizing multi-user interference through UE-specific non-orthogonal code covers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional non-orthogonal codebook using complex form coefficients is used to solve the Grassmannian line packing problem, then the Grassmannian sequence characteristics are maintained, but a great number of bits are required to express the coefficients
Solution Approach 1:
The patent changes the parameter representation from complex form coefficients to quantized coefficients using M-quadrature amplitude modulation (M-QAM) constellation. This parameter transformation reduces the number of bits required while maintaining the essential Grassmannian sequence characteristics through controlled quantization of the codebook entries.
Solution Approach 2:
The patent uses a quantized codebook that can be efficiently stored and transmitted compared to the conventional complex form codebook. The quantized representation with M-QAM constellation provides a more compact and practical implementation that reduces computational and storage requirements while maintaining the necessary mathematical properties for non-orthogonal multiple access.
2Productivity
If non-orthogonal multiple access scheme is used to accommodate explosive data traffic and increase transfer rate, then spectral efficiency is improved, but multi-user interference increases
Solution Approach 1:
The patent applies UE-specific non-orthogonal code covers (NCCs) that are individually tailored to each user equipment. Each UE is assigned a specific codebook and codeword configuration, creating locally optimized communication paths that minimize interference with other users while maintaining high spectral efficiency through non-orthogonal resource sharing.
Solution Approach 2:
The patent implements a control mechanism where the eNB transmits control information to UEs regarding the configured codewords and codebooks. This feedback loop allows the system to dynamically manage multi-user interference by coordinating the non-orthogonal code assignments and adjusting the quantization parameters based on channel conditions and interference levels.
3Loss of information
If quantization is applied to reduce the number of bits for codebook coefficients, then bit requirement is reduced, but codebook precision may be compromised
Solution Approach 1:
The patent carefully selects the quantization level M and the M-QAM constellation parameters to achieve an optimal balance between bit reduction and precision maintenance. By changing the representation parameters through controlled quantization, the system achieves sufficient precision for non-orthogonal multiple access operations while significantly reducing the number of bits required compared to complex form coefficients.
Solution Approach 2:
The patent applies quantization that provides more precision than the minimum theoretically required, using M-QAM with appropriately chosen M values. This excessive quantization ensures that the Grassmannian sequence characteristics are well-preserved even after quantization, providing a margin of precision that accommodates channel variations and interference while maintaining efficient bit usage.
Data Source
AI summary
A method and a device for performing communication by using a non-orthogonal code multiple access scheme in a wireless communication system are provided. Particularly, a terminal receives control information from a base station. The terminal modulates or demodulates a terminal-specific NCC on the basis of the control information. The terminal performs the non-orthogonal code multiple access scheme by using the terminal-specific NCC. The control information includes information on a codeword composed of a Grassmannian sequence. The codeword is included in a codebook predefined for the non-orthogonal code multiple access scheme. Each coefficient of the Grassmannian sequence is quantized on the basis of an M-quadrature amplitude modulation (M-QAM) constellation.