Non-orthogonal Code Multiple Access Uplink PAPR Control
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Solution Overview
Problem
Next-generation wireless communication systems face challenges in accommodating explosive data traffic, increasing transfer rates, supporting a large number of connected devices, reducing end-to-end latency, and achieving high energy efficiency, particularly in managing multi-user interference in non-orthogonal multiple access schemes.
Innovation Solution
The implementation of a non-orthogonal coded multiple access (NCMA) scheme that uses UE-specific non-orthogonal codebooks, defined by Grassmannian line packing, to minimize multi-user interference by allocating unique codewords to each user, thereby controlling Peak-to-Average Power Ratio (PAPR) based on the user's position in the cell and mobility, and employing DFT spreading to reduce PAPR in uplink transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If non-orthogonal coded multiple access scheme is used to increase transfer rate and support more users, then frequency usage efficiency and connectivity are improved, but multi-user interference increases and decoding accuracy deteriorates
Solution Approach 1:
The patent applies local quality by selecting different codebooks based on the specific channel conditions and user requirements. Different codebooks with different properties are assigned to different users or different transmission scenarios, allowing the system to optimize for both high throughput and low interference locally rather than using a uniform approach globally
Solution Approach 2:
The patent changes parameters by dynamically selecting codebooks with different spreading factors, code rates, or other characteristics based on channel state information, user mobility, and traffic conditions. This parameter adaptation allows the system to maintain decoding accuracy while achieving high frequency usage efficiency
2Productivity
If non-orthogonal codebooks are used to increase transfer rate, then productivity is improved, but Peak-to-Average Power Ratio increases and energy efficiency deteriorates
Solution Approach 1:
The patent changes the PAPR parameter by selecting codebooks with different properties and applying power control adjustments. The system dynamically adapts the codebook selection to minimize PAPR while maintaining the desired transfer rate, thereby improving energy efficiency without sacrificing productivity
3Reliability
If UE-specific codewords are allocated to minimize multi-user interference, then decoding accuracy is improved, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-defining and pre-configuring UE-specific codewords and codebooks before actual data transmission. The base station and UE exchange and store the necessary codebook information in advance, so that during data transmission, the devices can quickly select and use the appropriate codewords without complex real-time computations, thereby maintaining decoding accuracy while reducing operational complexity
Data Source
AI summary
Provided are a method and a device for transmitting uplink data by using a non-orthogonal code multiple access scheme in a wireless communication system. Particularly, a terminal receives control information from a base station. The terminal selects a terminal-specific codeword or receives allocation information of the terminal-specific codeword on the basis of the control information. The terminal transmits uplink data by using the terminal-specific codeword. The terminal-specific codeword is determined as a codeword having a value with a low peak-to-average power ratio (PAPR), when the terminal is located on the outside of a cell. The terminal-specific codeword is determined as a codeword having a value with a high PAPR, when the terminal is located in the center of the cell.