Interference-Aware Channel Feedback for MU-MIMO Mode Switching

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Solution Overview

Problem

Current mobile communication systems, such as 3GPP, LTE, and LTE-A, face performance deterioration when switching from SU-MIMO to MU-MIMO mode due to interference between UEs, as they do not consider inter-UE interference, leading to suboptimal channel state feedback and inefficient resource allocation.

Innovation Solution

An apparatus and method for feeding back channel state information that considers inter-UE interference, allowing the Base Station to determine the impact of additional UE access and perform mode switching to optimize MU-MIMO support, involving the generation and feedback of interference-reflecting CQI/PMI values and an accessible flag to manage inter-UE interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the system switches from SU-MIMO mode to MU-MIMO mode to increase system capacity and support multiple users, then the system throughput and resource utilization are improved, but inter-UE interference occurs causing communication performance deterioration for both existing and newly accessed UEs

Engineering Contradiction:

Improvesystem throughputVSAvoidcommunication performance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by having the UE calculate and feed back CQI values for both SU-MIMO and MU-MIMO modes before the actual mode switching occurs. The base station uses these pre-calculated CQI values to determine the optimal mode, preventing performance deterioration by making an informed decision in advance rather than switching blindly.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by having the UE measure interference from other UEs and calculate CQI values reflecting this interference, then feed back these values to the base station. The base station uses this feedback to select the appropriate transmission mode, ensuring that mode switching decisions are based on actual channel conditions and interference levels.

Inventive Principle:

Principle #23Feedback

2Device complexity

If the UE feeds back channel state information without considering inter-UE interference to simplify the feedback process, then the feedback overhead is reduced, but the base station cannot accurately determine the impact of additional UE access leading to suboptimal mode selection

Engineering Contradiction:

Improvefeedback process complexityVSAvoidchannel state information accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies segmentation by dividing the CQI feedback into two separate values: one for SU-MIMO mode and one for MU-MIMO mode. Each CQI value reflects the channel conditions specific to that mode, including interference considerations. This segmented approach provides the base station with precise information for mode selection without requiring a single complex CQI calculation.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS8855002B2Channel information feedback device and method thereof, and mode switching method, communication terminal device, and base station system using same

Publication Date: 2014.10.07 PANTECH CORP

AI summary

The present invention relates to a wireless communication system, and more particularly to a device for feeding back channel information in consideration of interference according to connection of an additional terminal and a technique for switching a mode by enabling a base station and the like to determine the connection of the additional terminal using the communication system.