Uplink Spatial Processing Matrix Switching for PAPR Reduction
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Solution Overview
Problem
In LTE wireless communication systems, the introduction of MIMO and multi-carrier techniques leads to a deterioration of the peak-to-average power ratio (PAPR)/cubic metric (CM) property in uplink channels, which affects battery standby-time and power consumption.
Innovation Solution
A method and apparatus for uplink transmission in a multi-antenna system that switches spatial processes by configuring different spatial processing matrices for transmission symbols, using space-frequency block coding (SFBC) or space-code block coding (SCBC), to maintain a low PAPR/CM ratio and balance transmit power between antennas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If MIMO and multi-carrier techniques are introduced to improve communication performance, then data transmission capability is improved, but PAPR/CM property deteriorates
Solution Approach 1:
The patent applies dynamics by making the spatial processing matrix switchable rather than fixed. The system dynamically selects between different spatial processing matrices (e.g., SFBC and SCBC matrices) based on channel conditions and transmission requirements, allowing the PAPR/CM property to be optimized while maintaining MIMO functionality. This dynamic adaptation resolves the contradiction by enabling the system to adjust its spatial processing characteristics in real-time.
Solution Approach 2:
The patent changes the parameter of spatial processing matrix configuration to resolve the contradiction. By switching between different spatial processing matrices with different mathematical properties (e.g., different unitary matrices in SFBC vs. SCBC), the system can maintain low PAPR/CM while preserving the data transmission capabilities of MIMO. The parameter change involves selecting matrices that satisfy both performance and energy efficiency requirements.
2Use of energy by moving object
If spatial processing matrices are switched to maintain low PAPR/CM ratio, then energy efficiency is improved, but system complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring multiple spatial processing matrices (SFBC and SCBC matrices) before transmission. The system prepares these matrices in advance and selects from them based on channel conditions, rather than computing new matrices in real-time. This preliminary preparation reduces the computational complexity of the switching operation while maintaining the ability to optimize PAPR/CM ratio.
Solution Approach 2:
The patent manages complexity by changing discrete parameters (matrix selection) rather than continuously optimizing matrix elements. The system switches between predefined matrix types (SFBC/SCBC) with known properties, avoiding the need for complex real-time matrix synthesis. This parameter-based approach simplifies the switching mechanism while achieving PAPR/CM optimization.
Data Source
AI summary
Provided are a method and apparatus for uplink transmission in a multi-antenna system. A terminal transmits a plurality of first transmission symbols via a plurality of antennas using a first spatial processing performed on the first transmission symbols, and transmits a plurality of second transmission symbols via a plurality of antennas using a second spatial processing performed on the second transmission symbols. At least one column or at least one row of a first spatial processing matrix used in the first spatial processing is switched to form a second SFBC matrix used in the second spatial processing. According to the present invention, peak-to average power (PAPR)/cubic metric (CM) ratio can be kept at a low level, and imbalanced transmission power among antennas can be evened out.