MU-MIMO Precoder Interference Suppression via Distributed Coordination

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Solution Overview

Problem

Current MU-MIMO communication techniques face challenges in efficiently managing interference and optimizing data transmission rates, particularly with errors in channel estimates and peak power capping, especially in distributed MU-MIMO systems.

Innovation Solution

Implementing a base station system with multiple radio units using smart interference suppression (IS) precoding schemes, including global and local IS, and hybrid precoding methods to optimize data transmission rates and handle errors in channel estimates, while capping peak antenna element power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional SVD precoding is used in MU-MIMO systems, then the system complexity is relatively low, but the data transmission rate is limited and interference management is insufficient

Engineering Contradiction:
Improvedata transmission rateVSAvoidprecoding scheme complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the precoding process into multiple stages: initial SVD precoding to establish basic spatial multiplexing, followed by interference suppression precoding to manage inter-user interference, and peak power capping to handle power constraints. This segmentation allows each stage to address specific aspects of the transmission problem independently, achieving high data rates through coordinated multi-stage processing while keeping individual processing steps manageable.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies preliminary action by first performing SVD decomposition to obtain initial precoding matrices before applying interference suppression techniques. The channel matrix is pre-processed to identify dominant spatial modes, and interference suppression precoders are designed based on these pre-computed modes. This preliminary structuring of the channel enables subsequent interference management to be more effective and computationally efficient.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If interference suppression precoding is applied to manage inter-user interference, then the data transmission rate improves, but the sensitivity to channel estimation errors increases

Engineering Contradiction:
Improvedata transmission rateVSAvoidperformance robustness to channel errors
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements beforehand cushioning by designing the interference suppression precoder to account for potential channel estimation errors in advance. The precoding scheme incorporates robustness mechanisms that cushion against the degradation caused by errors, ensuring that performance does not collapse when channel estimates are imperfect. This pre-built resilience allows the system to maintain high data rates even in the presence of estimation inaccuracies.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Power

If peak power capping is applied to antenna elements, then the system operates within power constraints, but the data transmission rate may be reduced

Engineering Contradiction:
Improveantenna peak powerVSAvoiddata transmission rate
Core Design Contradiction:
PowerVSProductivity

Solution Approach 1:

The patent applies dynamics by making the precoding matrices adaptive to power constraints. The interference suppression precoders are designed with dynamic power allocation that adjusts transmit power across different spatial modes and users based on channel conditions and interference levels. This dynamic power management allows the system to operate at peak power when conditions permit high rates while reducing power when constraints are tighter, thereby maintaining the highest possible data transmission rate within power limits.

Inventive Principle:
Principle #15Dynamics

4Productivity

If distributed MU-MIMO is implemented to improve coverage and capacity, then the system coverage and user capacity increase, but the interference management becomes more complex

Engineering Contradiction:
Improvesystem capacityVSAvoidinterference coordination complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent merges the interference suppression functions across multiple distributed radio points into a coordinated precoding framework. Instead of each radio point operating independently, the system combines channel state information from multiple points and applies joint interference suppression precoding that considers interferences from all distributed transmitters. This merging of interference management functions across distributed points achieves high system capacity while keeping the coordination complexity manageable through unified precoder design.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentUS11411589B2Interference suppression for multi-user multiple-input-multiple-output (MU-MIMO) pre-coders using coordination among one or more radio points
Publication Date: 2022.08.09 OUTDOOR WIRELESS NETWORKS LLC
  • US11411589B2 patent drawing
  • US11411589B2 patent drawing
  • US11411589B2 patent drawing

AI summary

This disclosure relates to Multi-User Multiple-Input-Multiple-Output (MU-MIMO) (including without limitation Distributed MU-MIMO (D-MU-MIMO)) communication techniques that employ interference suppression (IS) precoding schemes (including, for example, precoding schemes that use local interference suppression and precoding schemes that use global interreference suppression).