MIMO Beam Pair Grouping for Millimeter Wave WLAN Interference

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Solution Overview

Problem

Current beamforming techniques in WLAN systems are limited in their ability to efficiently manage multiple input multiple output (MIMO) transmissions, leading to suboptimal performance in terms of signal quality and interference mitigation.

Innovation Solution

The proposed solution involves an Access Point (AP) or a Proxy Coordination Point (PCP) performing user selection, pairing, and grouping based on measurements of signal quality, such as signal-to-noise ratio (SNR) or signal-to-interference-plus-noise ratio (SINR), acquired through analog beam training. This process allows for the identification of best and worst beams or beam pairs, which are then fed back to the AP/PCP for optimal MIMO frame setup and transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If current beamforming techniques are used in WLAN systems, then device complexity is reduced, but MIMO transmission efficiency and signal quality deteriorate

Engineering Contradiction:
ImproveMIMO transmission efficiencyVSAvoidbeamforming technique complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The beamforming technique is segmented into distinct phases: analog beam training for initial beam pair identification, followed by digital MIMO setup for optimized multi-user transmission. This segmentation allows each phase to specialize in specific tasks, improving overall MIMO transmission efficiency while managing device complexity through modular design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Analog beam training is performed as a preliminary action before MIMO transmission setup. Stations feed back best and worst beam pairs to the AP/PCP, which uses this information to preconfigure optimal beam assignments for subsequent MIMO transmissions, thereby improving transmission efficiency before actual data transfer begins

Inventive Principle:
Principle #10Preliminary action

2Object-affected harmful factors

If user selection and grouping based on SNR/SINR measurements are implemented, then interference mitigation is improved, but measurement and processing time increases

Engineering Contradiction:
Improveinterference levelVSAvoidbeam training and user selection time
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

Instead of evaluating all possible beam combinations, the system performs partial evaluation by identifying only the best and worst beam pairs for each station. Stations feed back limited information about top-performing and bottom-performing beams, which reduces measurement and processing time while still enabling effective interference mitigation through selective user grouping

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

Stations provide feedback to the AP/PCP regarding their best and worst beam pairs based on SNR/SINR measurements. This feedback mechanism enables the AP/PCP to make informed decisions about user grouping and beam assignment, improving interference mitigation while keeping the selection process efficient through targeted information exchange

Inventive Principle:
Principle #23Feedback

3Measurement precision

If multiple analog beams are transmitted for beam training, then beam selection accuracy is improved, but signal transmission time increases

Engineering Contradiction:
Improvebeam quality measurement accuracyVSAvoidanalog beam training time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system transmits multiple analog beams during training but only requires stations to evaluate and report the best and worst performers among them. This partial evaluation approach maintains measurement precision by considering multiple beam options while reducing overall training time by not requiring exhaustive analysis of all possible beam combinations

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS12237885B2Multiple input multiple output (MIMO) setup in millimeter wave (MMW) WLAN systems
Publication Date: 2025.02.25 INTERDIGITAL PATENT HOLDINGS INC
  • US12237885B2 patent drawing
  • US12237885B2 patent drawing
  • US12237885B2 patent drawing

AI summary

An AP/PCP may perform user selection/pairing/grouping based on a measurement of an analog transmission (e.g., signal to noise ratio (SNR) or signal to interference plus noise ratio (SINR)). The SNRs may be used, for example by the station, to determine best beams and/or beam pairs and/or worst beams and/or beam pairs. A station may feed back the best few beams and/or beam pairs for a Tx and Rx virtual antenna pair. A station may feed back the worst few beams for the Tx and Rx virtual antenna pair. The AP/PCP may receive the indication(s) and/or use the indication(s) to group the stations.