Reference Signal Coupling for Channel Estimation

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Solution Overview

Problem

In wireless communication networks, particularly in low signal-to-noise ratio (SNR) conditions, channel estimation quality is compromised due to insufficient power allocation to reference signals, leading to poor demodulation performance, especially for Machine-to-Machine (M2M) devices operating in remote locations with high path loss.

Innovation Solution

The method involves establishing a wireless connection with a first and second reference signal, determining a mapping between their associated antenna ports, and communicating this mapping to the wireless device, allowing for improved channel estimation by using power allocated to the second reference signal, thereby enhancing channel estimation quality for the first reference signal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If power is allocated to reference signals to improve channel estimation quality, then channel estimation accuracy improves, but available power for data transmission decreases

Engineering Contradiction:
Improvechannel estimation qualityVSAvoidpower available for data transmission
Core Design Contradiction:
Measurement precisionVSPower

Solution Approach 1:

The patent combines cell-specific reference signals (CRS) and user-specific demodulation reference signals (DMRS) into a unified channel estimation process. By establishing mapping relationships between antenna ports of CRS and CSI-RS, the system merges the power allocated to CRS with the power for DMRS, enabling the wireless device to perform channel estimation using both reference signals simultaneously. This resolving the contradiction by pooling available reference signal power without reducing data transmission power.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent enables a single set of antenna ports to serve multiple functions by establishing mapping relationships between different reference signal types. The same antenna ports carry both CRS and CSI-RS, allowing the system to universally use these ports for both cell-specific and user-specific channel estimation purposes. This multi-functionality increases the effective power available for channel estimation without requiring additional dedicated resources.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If mapping relationships between antenna ports are established to improve channel estimation, then channel estimation accuracy improves, but system complexity increases

Engineering Contradiction:
Improvechannel estimation accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent establishes antenna port mapping relationships between CRS and CSI-RS in advance through higher-layer signaling (RRC configuration) before actual data transmission occurs. This preliminary configuration of mapping relationships allows the wireless device to pre-configure its channel estimation process, eliminating the need for complex real-time mapping calculations during transmission. The complexity is shifted to the setup phase rather than the operational phase.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces antenna port mapping relationships as an intermediary mechanism that connects CRS and CSI-RS. Instead of directly combining different reference signal types with different structures, the mapping relationships serve as a mediator that aligns their antenna ports, enabling seamless integration. This intermediary approach simplifies the overall system architecture by providing a standardized interface between different reference signal systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3105875B1Reference signal coupling in a wireless network
Publication Date: 2020.05.13 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3105875B1 patent drawingFigure 1
  • EP3105875B1 patent drawingFigure 2~3
  • EP3105875B1 patent drawingFigure 4A~4B

AI summary

According to some embodiments, a method of coupling reference signals of a wireless network comprises establishing a wireless connection with a wireless device. The wireless connection comprises a first reference signal and a second reference signal and both the first and second reference signals are associated with one or more antenna ports. The method further comprises determining a mapping between the one or more antenna ports associated with the first reference signal and the one or more antenna ports associated with the second reference signal; communicating the mapping of antenna ports to the wireless device; and transmitting the first reference signal and the second reference signal to the wireless device according to the communicated mapping.