Transmitter Dynamic Multiple Access Mode Selection
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Solution Overview
Problem
The existing OFDM systems face challenges with high Peak Average Power Ratio (PAPR) leading to signal fluctuations and non-linear distortions, which affect performance, prompting the use of single-carrier systems like SC-FDMA in LTE, limiting multiple access modes and not well-suited for new systems with high peak data rate and spectral efficiency requirements.
Innovation Solution
A transmitting terminal that dynamically selects between Orthogonal Frequency Division Multiple Access (OFDMA) and Single Carrier-Frequency Division Multiplexing Access (SC-FDMA) based on requirements for link performance and time domain coverage, processing data through constellation modulation, sub-carrier mapping, spatial diversity, and time domain extension to optimize transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If OFDMA is used to improve link performance and spectral efficiency, then data rate and system capacity are improved, but PAPR increases causing signal fluctuations and non-linear distortions
Solution Approach 1:
The system dynamically selects between OFDMA and SC-FDMA multiple access modes based on real-time channel conditions, user requirements, and system state. This dynamic adaptation allows the system to optimize between data rate (OFDMA advantage) and signal quality (SC-FDMA advantage) by choosing the appropriate mode for each transmission scenario
Solution Approach 2:
The patent changes the fundamental parameter of multiple access mode (from fixed to variable) to resolve the contradiction. By allowing the system to switch between different access modes with different PAPR characteristics, it can adapt to varying requirements for link performance versus time domain coverage
2Reliability
If SC-FDMA is used to reduce PAPR and improve signal quality, then non-linear distortions are reduced, but spectral efficiency and peak data rate are limited
Solution Approach 1:
The system employs dynamic mode selection that transitions between SC-FDMA and OFDMA based on channel conditions and service requirements. When channel conditions are poor or coverage is prioritized, SC-FDMA provides superior signal quality; when conditions are good or throughput is prioritized, OFDMA delivers higher spectral efficiency
Solution Approach 2:
The transmitting terminal is designed to support both SC-FDMA and OFDMA multiple access modes, making it universally compatible with different service requirements. This multi-functionality allows the same system to serve both coverage-critical scenarios (using SC-FDMA) and capacity-critical scenarios (using OFDMA)
3Device complexity
If a single multiple access mode is used to simplify system design, then device complexity is reduced, but adaptability to different requirements is limited
Solution Approach 1:
The system implements dynamic multiple access mode selection that adapts to varying channel conditions, user positions, and service requirements. This dynamic approach provides high adaptability without requiring completely separate systems for different access modes
Solution Approach 2:
The patent segments the multiple access functionality into distinct modes (SC-FDMA and OFDMA) that can be independently selected based on requirements. This segmentation allows the system to maintain simplicity by using one mode at a time while preserving adaptability through the ability to switch between modes
Data Source
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AI summary
A transmitting terminal and a method for transmitting data are provided by the present invention, in which a multiple access mode is extended when transmitting upstream data. The method comprises: when the transmitting terminal transmits the upstream data, if the transmitting terminal has higher requirement on link performance than on time domain coverage, selecting the multiple access mode of OFDMA; and if the transmitting terminal has higher requirement on time domain coverage than on link performance, selecting the multiple access mode of SC-FDMA, and after selecting the multiple access mode, the transmitting terminal processing and then transmitting the data to be transmitted. The invention is adopted to solve the problem that a single multiple access mode cannot be well suitable in the related art, ensure the link performance of OFDMA, be beneficial to enhance the throughput of the entire network, and simultaneously solve the compatibility problem with the existing system by taking the coverage range into consideration.