MU-MIMO Feedback Scheduling via Segmented BCI Reporting

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Solution Overview

Problem

In MU-MIMO systems, the existing feedback schemes for reporting multiple best companion pre-coding matrix indices (BCIs) and delta channel quality indicators (ΔCQIs) lead to increased feedback overhead, which can result in reduced scheduling flexibility and performance due to potential BCI aging issues.

Innovation Solution

The method involves transmitting multiple BCIs and corresponding ΔCQIs with a longer frame period than a single BCI, and adjusting the feedback cycle for ΔCQIs to be shorter than that of BCIs, allowing for more accurate channel condition reflection and reduced overhead by reporting only the worst ΔCQI or using fixed BCI values.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple BCIs and corresponding ΔCQIs are reported frequently to improve scheduling flexibility and MU-MIMO performance, then scheduling flexibility and performance are improved, but feedback overhead increases

Engineering Contradiction:

Improvescheduling flexibilityVSAvoidfeedback overhead

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent segments the feedback reporting by dividing BCIs and ΔCQIs into different reporting groups. Some BCIs are reported frequently while others are reported less frequently, allowing the system to capture essential scheduling information without transmitting all BCI values at every opportunity, thus reducing overall feedback overhead while maintaining scheduling flexibility.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements periodic reporting with different cycles for different BCI groups. By setting longer reporting periods for certain BCIs and shorter periods for others, the system optimizes the balance between having up-to-date scheduling information and minimizing feedback overhead, applying periodic action at varying frequencies based on importance and channel variability.

Inventive Principle:

Principle #19Periodic action

2Measurement precision

If multiple BCIs are reported with the same feedback period to maintain accurate channel information, then channel accuracy is maintained, but feedback overhead increases

Engineering Contradiction:

Improvechannel condition accuracyVSAvoidfeedback overhead

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent segments BCIs into different reporting groups with different periodicities. Critical BCIs that require accurate channel information are reported frequently, while less critical BCIs are reported less frequently. This segmentation allows the system to maintain measurement precision for essential parameters while reducing the total quantity of feedback data transmitted.

Inventive Principle:

Principle #1Segmentation

3Reliability

If the feedback period for multiple BCIs is shortened to prevent BCI aging, then BCI freshness is improved, but feedback overhead increases

Engineering Contradiction:

ImproveBCI freshnessVSAvoidfeedback overhead

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies periodic action with varying frequencies to different BCI groups. By setting appropriate reporting periods for each BCI group based on its importance and susceptibility to aging, the system ensures that critical BCIs are refreshed frequently to maintain reliability, while less critical BCIs are updated less frequently to control feedback overhead.

Inventive Principle:

Principle #19Periodic action

4Ease of operation

If all BCIs are reported at the same frequency to simplify feedback management, then feedback management is simplified, but scheduling performance deteriorates

Engineering Contradiction:

Improvefeedback management simplicityVSAvoidMU-MIMO performance

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The patent segments BCIs into different reporting groups with different periodicities based on their importance for scheduling decisions. This segmentation allows the system to prioritize feedback management for critical BCIs while reducing reporting for less critical ones, thereby maintaining MU-MIMO performance without requiring uniform high-frequency reporting of all BCIs.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS9350431B2Wireless communication method for a MU-MIMO system, wireless communication terminal for communicating with a base station in a MU-MIMO system, and base station for communicating with wireless communication terminals in a MU-MIMO system

Publication Date: 2016.05.24 PANASONIC INTELLECTUAL PROPERTY CORP OF AMERICA

AI summary

A wireless communication method, a terminal and a base station are provided. The method includes the step of transmitting a plurality of best companion pre-coding matrix indexs (BCIs) and corresponding delta channel quality indicators (ΔCQIs) from the terminal to the base station, wherein the period of frames for transmitting the plurality of BCIs is larger than the period of frames for transmitting a single BCI. The method, terminal and base station according to the present disclosure can greatly increase scheduling flexibility at base station side and improve MU-MIMO performance without increasing feedback overhead of channels.