Adaptive MIMO Precoding Taps for PAPR and Inter-Stream Control
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Solution Overview
Problem
Conventional MIMO systems face issues with increased peak to average power ratio (PAPR) due to precoding, leading to suppressed transmission power and deteriorated signal-to-noise ratio (SNR), while also experiencing inter-stream interference.
Innovation Solution
A radio communication system that includes a precoding unit, transmission power control units, amplification units, and a number-of-taps control unit to manage the number of precoding taps based on received signal quality information, thereby improving SNR and suppressing inter-stream interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If precoding is performed in a MIMO system, then inter-stream interference is suppressed, but peak to average power ratio (PAPR) increases and transmission power is suppressed
Solution Approach 1:
The patent applies dynamics by making the number of precoding taps variable rather than fixed. The number-of-taps control unit dynamically adjusts the number of taps based on feedback information about received signal quality, allowing the system to adapt between suppressing inter-stream interference and maintaining transmission power according to current channel conditions.
Solution Approach 2:
The patent changes the parameter of the number of precoding taps to resolve the contradiction. By varying this parameter based on signal quality feedback, the system can optimize the balance between interference suppression and power maintenance, preventing excessive PAPR while still providing precoding benefits when needed.
2Reliability
If transmission power is suppressed to prevent distortion, then amplifier nonlinear distortion is avoided, but signal to noise power ratio (SNR) deteriorates
Solution Approach 1:
The system dynamically adjusts the number of precoding taps based on feedback about signal quality and amplifier characteristics. This allows the system to maintain higher transmission power when channel conditions permit, improving SNR while still preventing distortion through adaptive control rather than continuous suppression.
Solution Approach 2:
The patent implements feedback control where the number-of-taps control unit receives feedback information about received signal quality from the reception device or calculates quality information using amplifier characteristics. This feedback loop enables the system to adjust precoding parameters to maintain optimal SNR while avoiding distortion.
3Reliability
If the number of precoding taps is increased, then inter-stream interference is reduced, but PAPR increases and transmission power must be suppressed
Solution Approach 1:
The patent makes the number of precoding taps dynamic rather than continuously variable. The number-of-taps control unit selects from discrete tap values based on feedback conditions, reducing computational complexity compared to continuous optimization while still achieving adaptive interference suppression.
Data Source
AI summary
A radio communication system that performs MIMO transmission. The radio communication system includes a precoding unit that precodes multi-streams of transmission signals in a time domain; a plurality of transmission power control units that controls transmission power of each multi-stream precoded by the precoding unit. Further, there is a plurality of amplification units that amplifies each multi-stream precoded by the precoding unit in accordance with control of the plurality of transmission power control units; and a number-of-taps control unit that performs control to change the number of taps of the precoding unit to improve communication quality of the multi-streams on the basis of quality information of a received signal fed back from a reception device that has received the multi-stream amplified by each of the plurality of amplification units.