CSI Feedback Reporting for Distributed MIMO Networks

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current 5G wireless communication networks face high feedback overhead and computational complexity in CSI reporting, especially in distributed MIMO deployments, where existing codebooks are not supported, leading to inefficiencies in precoding and increased latency.

Innovation Solution

The proposed method involves generating and reporting CSI feedback using a precoder matrix based on a first and second basis set, with combining coefficients for complex scaling, specifically designed for distributed MIMO cooperative transmissions, reducing feedback overhead and computational complexity by selecting basis vectors from these sets for antenna and CSI-RS port groups.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If existing codebooks are used for CSI reporting in distributed MIMO deployments, then compatibility with current systems is maintained, but feedback overhead and computational complexity increase significantly

Engineering Contradiction:

Improvecompatibility with current systemsVSAvoidfeedback overhead and computational complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The distributed antenna system is divided into multiple antenna port groups, each group being handled separately in the CSI reporting process. This segmentation allows the UE to report CSI for each group independently, reducing the overall feedback overhead compared to reporting for all antennas individually while maintaining compatibility with existing codebook structures.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a new dimension to CSI reporting by grouping antenna ports and reporting at the group level rather than individual port level. This dimensional change from port-level to group-level reporting reduces feedback overhead while the patent also adds new fields (such as antenna port group indicator and port group selection indicator) to capture the grouping information efficiently.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Measurement precision

If detailed CSI reporting for each antenna port is performed, then precoding accuracy is improved, but feedback overhead and latency increase

Engineering Contradiction:

Improveprecoding accuracyVSAvoidfeedback latency

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

Instead of reporting CSI for every single antenna port, the patent applies partial action by selecting representative antenna ports within each group and reporting CSI based on these selected ports. This partial reporting approach maintains sufficient precoding accuracy while significantly reducing feedback overhead and latency compared to exhaustive per-port reporting.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The antenna system is segmented into port groups, and CSI reporting is performed at the group level rather than individual port level. This segmentation reduces the total number of CSI reports needed while maintaining precision through the selection of representative ports within each group, thereby reducing latency.

Inventive Principle:

Principle #1Segmentation

3Adaptability or versatility

If codebook-based precoding is implemented for distributed MIMO, then support for cooperative transmissions is achieved, but existing codebooks are not supported and new complexity is introduced

Engineering Contradiction:

Improvesupport for cooperative transmissionsVSAvoidcodebook implementation complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extends existing codebook structures to support distributed MIMO cooperative transmissions, making the codebook multi-functional. The same codebook framework can be used for both traditional MIMO and distributed MIMO scenarios by configuring different antenna port groups, thereby supporting cooperative transmissions without requiring entirely new codebooks.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent introduces dynamic configuration of antenna port groups through higher layer parameters, allowing the system to adapt between different distributed MIMO deployment scenarios. The grouping and reporting structure can be dynamically adjusted based on the specific deployment configuration, reducing implementation complexity for different scenarios.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS20240340052A1Methods and apparatuses for CSI reporting for joint transmission in a wireless communications network

Publication Date: 2024.10.10 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV

AI summary

The embodiments of the present disclosure relate to methods and apparatuses for the generation and transmission/reception of a CSI report or CSI feedback report. The method performed by a UE includes: receiving from a network node a CSI report configuration indicating a number of antenna port groups or CSI-RS port groups; determining based on the CSI report configuration a precoder matrix for a number of antenna or CSI-RS port groups; generating, a CSI feedback report comprising a Precoder Matrix Indicator indicating the precoder matrix for the number of antenna or CSI-RS port groups; and reporting, to the network node, the CSI report or the CSI feedback report. The embodiments also relate to a method performed by a network node, a UE and a network node.