Advanced MIMO Receivers for 5G Sub-band CQI Reporting

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current 5G wireless systems face challenges in efficiently reporting sub-band channel quality data for frequency selective scheduling, leading to suboptimal performance in MIMO systems.

Innovation Solution

Implementing advanced receivers in user equipment and network nodes to estimate signal-to-interference-plus-noise ratio (SINR) and compute channel quality indicators (CQI), which enables efficient reporting of sub-band CQI and precoding matrix information, facilitating improved MIMO system performance through dynamic modulation and coding scheme adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If advanced receivers are implemented to estimate SINR and compute CQI for sub-band reporting, then spectral efficiency and system throughput are improved, but device complexity and processing requirements increase

Engineering Contradiction:

Improvespectral efficiencyVSAvoidreceiver complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the channel quality reporting into sub-band CQI reports rather than wideband reporting. This allows the receiver to estimate SINR and compute CQI for specific frequency sub-bands, enabling frequency-selective scheduling that improves spectral efficiency while distributing the processing complexity across multiple sub-band analyses rather than requiring exhaustive wideband processing.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The receiver performs preliminary SINR estimation and CQI computation for multiple sub-bands before the scheduling decision is made. This preliminary action provides the network with pre-computed channel quality information, allowing the scheduler to make informed decisions without requiring complex real-time calculations during the scheduling instant, thus improving overall system efficiency.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If frequency selective scheduling is enabled through sub-band CQI reporting, then cell edge user throughput is improved, but signaling overhead and reporting complexity increase

Engineering Contradiction:

Improvecell edge user throughputVSAvoidsignaling overhead

Core Design Contradiction:

ProductivityVSLoss of information

Solution Approach 1:

The patent implements local quality assessment by computing CQI for specific sub-bands rather than reporting a single wideband CQI. This allows cell edge users to report channel quality for specific frequency regions where they experience better conditions, enabling the scheduler to allocate resources in those sub-bands and thereby improve cell edge throughput without requiring comprehensive reporting of all frequency resources.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Instead of reporting CQI for all possible sub-bands, the system implements partial reporting where users report CQI for a selected subset of sub-bands that are most relevant to their channel conditions. This partial action reduces the signaling overhead compared to exhaustive sub-band reporting while still providing sufficient information for effective frequency-selective scheduling to improve cell edge performance.

Inventive Principle:

Principle #16Partial or excessive action

3Adaptability or versatility

If dynamic modulation and coding scheme adjustments are performed based on CQI feedback, then data rate adaptability is improved, but processing time and latency increase

Engineering Contradiction:

Improvemodulation adaptabilityVSAvoidprocessing latency

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent implements a feedback mechanism where the receiver computes CQI based on SINR estimation and feeds this information back to the transmitter. The transmitter uses this feedback to dynamically adjust the modulation and coding scheme (MCS) for subsequent transmissions. This feedback loop enables adaptability to changing channel conditions while the pre-computed CQI values reduce the processing time required for MCS selection compared to real-time calculations.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11356161B2Multiple-input multiple-output system performance using advanced receivers for 5G or other next generation networks

Publication Date: 2022.06.07 AT&T INTELLECTUAL PROPERTY I L P

AI summary

Fast calculation of channel state information using demodulation reference signals (DM-RS) is provided herein. The channel state information can be calculated by estimating the signal to noise ratio of a communication link based on the DM-RS, and then estimating the channel quality indicator based on the SINR. The advanced receivers can use list-based detection methods which the estimated SINR can improve the performance thereof. Channel state information is traditionally calculated based on the channel state reference signals (CS-RS). Demodulation reference signals, which are used for channel estimation for a data channel, are transmitted at different times than CS-RS however, and so some portions of the channel state information including layer indicator (LI) and channel quality indicator (CQI) can be calculated based on the demodulation reference signals, allowing a network to adapt more quickly to changing channel conditions, without having to transmit a CS-RS.