MIMO Precoder Weight Selection for Multiplicative Noise
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Solution Overview
Problem
MIMO communication systems face throughput limitations due to multiplicative noise, which is exacerbated by dominant signal paths overpowering weaker paths, leading to inter-stream interference and reduced signal-to-noise ratios, especially in scenarios with rich scattering and high signal strength noise conditions.
Innovation Solution
The method involves determining precoder weights based on information from non-precoded reference symbols to reduce energy allocation to dominant signal paths relative to non-dominant paths, using channel estimates, Rank Indicator (RI), Pre-coding Matrix Indicator (PMI), and Channel Quality Indicator (CQI, thereby decreasing multiplicative noise impact and improving throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power is increased for data streams with low SNR, then signal-to-noise ratio improves, but multiplicative noise increases proportionally to signal strength
Solution Approach 1:
The patent changes the parameter of power allocation by introducing precoder weights that adjust the energy distribution across different data streams. Instead of uniform or simple proportional power allocation, the system modifies the transmission parameters through precoding matrices that reduce power on dominant paths and maintain or increase power on weaker paths, thereby improving SNR without proportionally increasing multiplicative noise.
Solution Approach 2:
The patent applies local quality by treating different data streams differently based on their channel conditions. Dominant data streams receive reduced power through precoder design, while weaker data streams receive enhanced or maintained power. This localized power adjustment optimizes each stream's SNR independently, preventing multiplicative noise from scaling uniformly across all streams.
2Object-affected harmful factors
If fewer data streams are transmitted to avoid wasting power, then multiplicative noise impact decreases, but peak data rate decreases
Solution Approach 1:
The patent changes the parameter of data stream utilization by using precoder weights to enable effective transmission of more data streams than traditionally used. By adjusting the precoding matrices, the system can transmit higher rank transmissions (more streams) while maintaining acceptable SNR levels through intelligent power distribution, thereby increasing peak data rate without being limited by multiplicative noise on dominant streams.
Solution Approach 2:
The patent uses reference signals (pilots) to create copies of channel state information that are then used to design precoders. These precoded reference signals allow the receiver to estimate channel conditions and determine optimal precoder weights, enabling the system to replicate successful power allocation strategies across multiple data streams and increase overall throughput.
3Productivity
If dominant signal paths are allowed to transmit at full power, then throughput on strong paths is maximized, but inter-stream interference increases and weaker paths suffer from low SNR
Solution Approach 1:
The patent applies local quality by differentiating power allocation across different spatial paths. Instead of treating all paths equally or allowing dominant paths to dominate, the precoder design locally adjusts power distribution to reduce energy on dominant paths and compensate for weaker paths. This creates non-uniform power distribution that balances SNR across streams while reducing inter-stream interference.
Solution Approach 2:
The patent introduces asymmetry in power allocation by using precoder weights that deliberately create unequal energy distribution across data streams. The precoding matrices are designed to suppress dominant paths and enhance weaker paths, creating an asymmetric power profile that optimizes overall system performance rather than maximizing individual strong paths.
Data Source
AI summary
The method and apparatus disclosed herein improve throughput conditions limited by multiplicative noise by determining precoder weights for each data stream communicated between a MIMO transmitter node and a MIMO receiver node. The precoder weights are determined based on information derived from non-precoded reference symbols to decrease the energy allocated to the dominant signal path relative to the energy allocated to the non-dominant signal paths.