Uplink MIMO Scheduling via Beamformed Reference Signals

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Solution Overview

Problem

Current wireless communication systems, particularly in LTE technology, face challenges in efficiently managing uplink transmissions and handover decisions due to reliance on downlink measurements, which can lead to interference and suboptimal resource allocation in user-centric networks.

Innovation Solution

The implementation of beamformed reference signals allows wireless nodes to identify and adjust transmission parameters, enabling more accurate interference management and resource allocation by using beamforming techniques to select optimal transmission settings for subsequent uplink transmissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If downlink measurements are used for handoff decisions, then handover framework can be established, but interference and suboptimal resource allocation occur in user-centric networks

Engineering Contradiction:

Improvehandover frameworkVSAvoidinterference

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent inverts the traditional downlink measurement approach by using uplink beamformed reference signal measurements for handoff decisions. Instead of the network measuring downlink signals from base stations, user equipment measures uplink signals from base stations, fundamentally changing the measurement direction to eliminate interference issues in user-centric networks

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the measurement parameter from downlink signal strength to uplink reference signal quality. By using reference signal received quality (RSRQ) and reference signal received power (RSRP) from uplink beamformed signals, the system achieves more accurate channel state information and interference estimation for handover decisions

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If beamformed reference signals are used for uplink MIMO scheduling, then interference management and resource allocation improve, but data overhead in uplink grants increases

Engineering Contradiction:

ImproveinterferenceVSAvoiddata overhead

Core Design Contradiction:

Object-affected harmful factorsVSLoss of information

Solution Approach 1:

The patent performs preliminary channel estimation and interference covariance matrix calculation using beamformed reference signals before actual data transmission. This preliminary action allows the network to pre-determine optimal precoding matrices and resource allocation, reducing the need for extensive signaling during data transmission

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces beamformed reference signals as an intermediary element that carries channel state information and interference characteristics. These reference signals serve as a mediator between the physical channel and the scheduling algorithm, enabling accurate interference management without requiring direct transmission of large amounts of channel state information

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If beamforming techniques are used to select optimal transmission settings, then transmission accuracy improves, but device complexity increases

Engineering Contradiction:

Improvetransmission accuracyVSAvoidbeamforming implementation

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements beamforming for specific reference signal transmissions rather than for all uplink transmissions. By applying beamforming selectively to reference signals that carry channel state information, the system achieves transmission accuracy improvements without requiring full beamforming complexity for every transmission

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent uses beamformed reference signals as copies or representations of the actual data transmission channels. These reference signals replicate the channel characteristics and interference conditions, allowing the network to determine optimal transmission settings without directly processing the full complexity of actual data transmissions

Inventive Principle:

Principle #26Copying

Data Source

PatentUS11569875B2Uplink multiple-input multiple-output (MIMO) scheduling using beamformed reference signals

Publication Date: 2023.01.31 QUALCOMM INC

AI summary

Aspects of the present disclosure provide methods and apparatus for selecting beamforming parameters for uplink transmissions based on an uplink reference signal. An example method generally includes identifying one or more parameters for beamformed transmission to a transmit receive point (TRP), transmitting a reference signal using beamforming in accordance with the identified parameters, and receiving, from the TRP in response to the reference signal, signaling for adjusting the one or more parameters for one or more subsequent beamformed transmissions.