CSI-RS Configuration for Downlink Transmission Point Selection

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Solution Overview

Problem

In CoMP scenario four Macro+RRH wireless networks, identifying the optimal downlink transmission points for user equipment is challenging due to shared cell IDs, making traditional reporting mechanisms ineffective, and requiring alternative mechanisms to evaluate channel metrics between transmission points and user equipment.

Innovation Solution

The wireless network employs channel state information (CSI) between transmission points and user equipment, configuring the equipment to report CSI-RS measurements for selected downlink transmission points, using a transmission point selection module to rank and select the best points based on CSI-RS index and other metrics, and configuring the reporting period to optimize downlink transmissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If transmission points share a single cell ID in CoMP scenario four, then user equipment reporting mechanisms can remain simplified, but the network cannot effectively identify and select optimal downlink transmission points

Engineering Contradiction:

Improveuser equipment reporting mechanism simplicityVSAvoidtransmission point identification accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent introduces CSI-RS (Channel State Information Reference Signal) as an intermediary mechanism. Instead of relying on traditional cell ID-based reporting, the network configures multiple CSI-RS resources with different resource configurations (time, frequency, spatial). The UE measures channel quality on these CSI-RS resources and reports back, enabling the network to identify the best downlink transmission point without changing the fundamental cell ID structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the measurement parameters from cell ID-based to CSI-RS resource-based. By configuring multiple CSI-RS resources with different time-frequency-spatial parameters and having the UE measure and report on these resources, the system can distinguish between different transmission points even when they share the same cell ID, thus resolving the identification problem.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the network configures UE to report CSI-RS measurements for multiple transmission points, then optimal downlink transmission point selection is enabled, but signaling overhead and measurement complexity increase

Engineering Contradiction:

Improvedownlink transmission point selection accuracyVSAvoidCSI-RS measurement and reporting complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies partial action by having the UE measure and report CSI-RS measurements for only a subset of transmission points rather than all possible transmission points. The network configures CSI-RS resources for multiple transmission points but the UE selectively measures and reports based on which transmission points are relevant to its current position and service requirements, reducing measurement complexity while maintaining selection accuracy.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent segments the CSI-RS measurement and reporting process into multiple independent CSI-RS resource configurations. Each CSI-RS resource corresponds to a specific transmission point or group of transmission points, allowing the UE to process measurements in manageable segments rather than as a single complex task, thereby reducing overall device complexity.

Inventive Principle:

Principle #1Segmentation

3Measurement precision

If CSI-RS reporting period is shortened to capture fast fading variations, then channel quality information becomes more current, but signaling overhead and power consumption increase

Engineering Contradiction:

Improvechannel quality information freshnessVSAvoidUE power consumption for CSI-RS reporting

Core Design Contradiction:

Measurement precisionVSLoss of energy

Solution Approach 1:

The patent implements periodic CSI-RS reporting where the UE measures and reports channel quality information at configured periodic intervals rather than continuously. The network can configure different reporting periods based on channel conditions, traffic requirements, and UE capabilities, allowing the system to capture fast fading variations when necessary while conserving UE energy during more stable periods.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent introduces dynamic adjustment of CSI-RS reporting parameters. The network can adaptively change the reporting period, CSI-RS resource configuration, and measurement bandwidth based on current channel conditions, UE mobility, and network load. This dynamic approach ensures channel quality information remains current when needed while minimizing power consumption during stable conditions.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS9319965B2Apparatuses and methods for CSI-RS configuration in distributed RRH systems

Publication Date: 2016.04.19 INTEL CORP

AI summary

Apparatuses and methods for channel state information reference signal (CSI-RS) configuration in distributed remote radio head (RRH) systems are described. A transmission point selection module can receive a user equipment (UE) signal via a transmission point from a plurality of transmission points sharing a single cell identification. A downlink transmission point can be selected based on the UE signal. The UE can then be configured to report CSI-RS measurements for the selected downlink transmission point.