Coordinated Multi-Cell MIMO Precoding Under Imperfect CSI

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Solution Overview

Problem

Existing MIMO WNV systems face challenges in managing inter-SP and inter-cell interference due to obliviousness among service providers, imperfect CSI, and the need for efficient resource allocation under long-term transmit power constraints, particularly in multi-cell scenarios.

Innovation Solution

A coordinated precoding scheme for online multi-cell MIMO WNV that minimizes long-term precoding deviation using imperfect CSI, allowing distributed implementation without CSI exchange or central power control, and mitigates interference through semi-closed form precoding based on current CSI.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If strict physical isolation is used to allocate exclusive subsets of antennas or orthogonal sub-channels to each SP, then interference among service providers is eliminated, but the utilization of spatial spectrum sharing enabled by MIMO beamforming is not fully utilized

Engineering Contradiction:

Improveisolation of virtual networksVSAvoidspectral efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent segments the precoding function into two independent components: virtual precoding matrices designed by each SP based on their own channel state information, and a coordination precoding matrix designed by the network operator to manage interference. This segmentation allows each SP to independently optimize for their service requirements while the coordination layer ensures overall system performance, resolving the contradiction between isolation and spectral efficiency.

Inventive Principle:

Principle #1Segmentation

2Productivity

If service providers are allowed to share all antennas and spectrum resources simultaneously with independent virtual precoding, then spatial spectrum sharing is maximized, but unacceptable interference among service providers is induced

Engineering Contradiction:

Improvespectral efficiencyVSAvoidinterference among service providers

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The coordination precoding matrix acts as an intermediary between the independent virtual precoding matrices of different service providers. It processes the combined signals from multiple SPs to suppress inter-SP interference before transmission, allowing full resource sharing while maintaining acceptable interference levels. This intermediary layer enables both high spectral efficiency and controlled interference.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If offline multi-cell coordinated precoding is implemented, then system performance is improved, but the complexity of CSI exchange and centralized control increases significantly

Engineering Contradiction:

Improvesystem performanceVSAvoidcoordination overhead

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Each service provider performs preliminary design of their virtual precoding matrices based on their own channel state information before the coordination stage. This preliminary action allows the coordination precoding to focus only on managing inter-SP interference rather than dealing with all precoding decisions, significantly reducing the complexity of CSI exchange and centralized control while maintaining system performance.

Inventive Principle:

Principle #10Preliminary action

4Speed

If per-slot design optimization is used for MIMO WNV, then immediate adaptation to channel conditions is achieved, but long-term energy consumption is not optimized

Engineering Contradiction:

Improveadaptation speedVSAvoidenergy consumption

Core Design Contradiction:

SpeedVSUse of energy by stationary object

Solution Approach 1:

The patent employs a dynamic optimization approach where the coordination precoding matrix is updated based on current channel state information to achieve immediate adaptation, while simultaneously optimizing for long-term energy consumption through Lyapunov optimization techniques. This dynamic approach allows the system to balance between rapid adaptation and energy efficiency by making decisions that consider both immediate and long-term objectives.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS12556242B2Online multi-cell coordinated multiple input-multiple output (MIMO) wireless network virtualization with imperfect channel state information (CSI)

Publication Date: 2026.02.17 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A method, system and apparatus are disclosed. According to one or more Examples, an infrastructure network node (16) for providing a virtual multiple-input multiple-output. MIMO, cellular network supporting a plurality of network nodes (16) associated with a plurality of service providers. SPs is provided. The infrastructure network node (16) is configured to determine a downlink coordinated precoder for online multi-cell MIMO wireless network virtualization. WNV, where the downlink coordinated precoder is based at least on imperfect channel state information. CSI, and to optionally indicate the downlink coordinated precoder.