Implicit Sounding for MU-MIMO Antenna Utilization

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Solution Overview

Problem

In MUMIMO systems, access points with more antennas than supported by receiving stations are unable to utilize all their antennas for downlink transmissions due to limitations in explicit sounding protocols, resulting in wasted resources.

Innovation Solution

The implementation of implicit sounding methods at the access point to compute channel estimates for all its antennas based on uplink data from receiving stations, allowing for the generation of a precoding matrix that enables transmission using all available antennas, even if receiving stations support fewer antennas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If explicit sounding protocol is used, then receiving stations can provide feedback matrices for channel estimation, but access points cannot utilize antennas beyond the number supported by receiving stations

Engineering Contradiction:

Improveantenna utilization flexibilityVSAvoidwasted antenna resources

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent inverts the traditional sounding approach by having the access point transmit a sounding packet and then computing channel estimates for all its antennas based on the received signal at the station, rather than having the station feedback channel estimates for all access point antennas. This inversion allows the access point to derive channel state information for antennas beyond what the station explicitly supports, enabling full antenna utilization.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent uses the station's received signal as an intermediary to infer channel characteristics for all access point antennas. By analyzing the signal received at the station's antennas, the access point can compute channel estimates for its own antennas through mathematical relationships, effectively using the station's reception as a mediator to obtain information about access point antenna channels that would otherwise be inaccessible.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Loss of information

If access point transmits sounding packet from all antennas, then channel information for all antennas can be obtained, but receiving stations cannot provide feedback for antennas they do not support

Engineering Contradiction:

Improvechannel state information completenessVSAvoidfeedback protocol complexity

Core Design Contradiction:

Loss of informationVSEase of operation

Solution Approach 1:

The access point performs self-service by computing its own channel estimates for all antennas based on the signal received from its sounding packet transmission. Instead of relying on receiving stations to provide feedback for all antennas, the access point independently derives the channel state information for all its antennas using the received signal and mathematical computations, eliminating the need for complex feedback mechanisms for unsupported antennas.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent inverts the traditional feedback direction by having the access point compute channel estimates for all its antennas based on signals received at the station, rather than having the station feedback channel estimates for all access point antennas. This inversion allows the access point to obtain complete channel state information for all its antennas without requiring the station to support or feedback information for antennas beyond its capabilities.

Inventive Principle:

Principle #13The other way round (Inversion)

3Adaptability or versatility

If access point is forced to act as fewer antenna system, then compatibility with receiving stations is maintained, but transmission capacity is reduced

Engineering Contradiction:

Improvedownward compatibilityVSAvoidtransmission capacity

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent implements dynamic antenna utilization where the access point can adaptively use all its antennas for transmission based on real-time channel conditions and station capabilities. By computing channel estimates for all antennas regardless of station support, the system dynamically optimizes transmission capacity while maintaining compatibility, allowing the access point to fully utilize its antenna resources without being statically constrained to match station limitations.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent segments the channel estimation process into two parts: the sounding packet transmission from all access point antennas, and the independent computation of channel estimates for each antenna. This segmentation allows the access point to maintain downward compatibility by transmitting compatible signaling while simultaneously computing and utilizing channel information for all antennas, thereby preserving both compatibility and transmission capacity.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS10873379B1Systems and methods for performing implicit sounding in multi-user multiple input multiple output (MU-MIMO) systems

Publication Date: 2020.12.22 MARVELL ASIA PTE LTD

AI summary

Embodiments described herein provide a method for performing beamforming in a multiple-user-multiple-input-multiple-output (MUMIMO) system. At a MUMIMO access point, MUMIMO data may be received from a station of a plurality of stations. Uplink channel state information may be obtained, from the MUMIMO data, representing an uplink channel between the station and the MUMIMO access point. The uplink channel includes signals transmitted from the station using the second number of antennas. Downlink channel state information may be computed, based on the uplink channel state information, representing a downlink channel between the MUMIMO access point and the station.