NOMA Spreading Sequence Selection via Received Power Feedback
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Solution Overview
Problem
Current Non-Orthogonal Multiple Access (NOMA) systems face performance issues due to power differences between mobile stations at the transmitting and receiving ends, leading to poor reception performance due to path losses and interference cancellation challenges.
Innovation Solution
A method for selecting spreading sequences and adjusting transmission power based on received powers at the receiving end, grouping mobile stations by their received powers, and determining spreading sequence groups and transmission power adjustments to minimize interference and optimize power distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If power differences are used to distinguish multiple mobile stations in NOMA system, then the number of simultaneously scheduled mobile stations increases, but reception performance deteriorates due to path losses and power differences between transmitting and receiving ends
Solution Approach 1:
The patent changes the parameter basis from transmission power differences to received power differences. By grouping mobile stations according to their received powers at the receiving end and selecting spreading sequences based on these received power levels, the system maintains the ability to distinguish multiple users while compensating for path loss effects, thus improving reception performance without reducing system capacity
Solution Approach 2:
The patent introduces feedback mechanisms where the receiving end determines spreading sequence groups based on received powers and feeds back this information to mobile stations. This feedback loop enables dynamic adjustment of spreading sequences according to actual received power conditions, allowing the system to adapt to varying path losses and maintain reliable reception while supporting multiple simultaneous users
2Ease of operation
If spreading sequences are selected based on transmission powers at transmitting end, then user distinction is achieved, but decoding efficiency deteriorates due to mismatch between transmitting and receiving power differences
Solution Approach 1:
The patent fundamentally changes the parameter basis from transmission power to received power for spreading sequence selection. The receiving end determines appropriate spreading sequence groups based on actual received power levels of different user groups, and this information is fed back to mobile stations. This ensures that spreading sequences are selected according to the actual conditions at the receiving end, improving decoding efficiency while maintaining user distinction capability
Solution Approach 2:
The patent shifts the decision-making dimension from the transmitting end to the receiving end. Instead of selecting spreading sequences based on transmitted power levels at the source, the system makes selection decisions based on received power levels at the destination, adding a new dimension of control that directly addresses the actual decoding conditions and improves overall system efficiency
Data Source
AI summary
Provided in embodiments of the present disclosure are a method for selecting spreading sequences, a method for adjusting a transmission power and communication apparatuses. The method for selecting spread sequences according to the embodiments of the present disclosure includes: obtaining received powers of a plurality of user groups at a receiving end; determining spread sequence groups for the user groups in a spreading sequence set according to the obtained received powers.