Cell-Based Highly Detectable Pilot Multiplexing for Interference Mitigation

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Solution Overview

Problem

Wireless communication systems face challenges in detecting pilot signals due to strong interference, leading to positioning inaccuracies, especially in urban and indoor areas where satellite measurements are unavailable, and existing solutions like pilot interference cancellation and time diversity have limited effectiveness.

Innovation Solution

The implementation of cell-based highly detectable pilot (HDP) multiplexing, which involves determining HDP opportunities, selecting subslots for transmission, and activating multiple sectors within a cell for HDP signal transmission, allowing for improved pilot signal detection and location accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional pilot transmission methods are used, then system compatibility is maintained, but pilot signal detectability deteriorates in high interference environments

Engineering Contradiction:
Improvepilot signal detectabilityVSAvoidinterference from other sectors
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The pilot transmission opportunity is segmented into multiple subslots, and different sectors are assigned to transmit in different subslots. This time-division approach segments the interference problem, allowing each sector to transmit its pilot signal without overlapping with other sectors, thereby improving detectability in high interference environments.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically activates specific sectors based on detected HDP opportunities and selects appropriate subslots for transmission. This dynamic adaptation allows the system to optimize pilot transmission timing and sector selection based on current channel conditions and interference levels, enhancing pilot signal detectability.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If multiple sectors transmit simultaneously, then location accuracy improves through better signal coverage, but interference between sectors increases

Engineering Contradiction:
Improvelocation accuracyVSAvoidinterference between sectors
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The transmission timeline is segmented into subslots, with each sector assigned to a specific subslot for pilot transmission. This prevents simultaneous transmission from multiple sectors, eliminating inter-sector interference while maintaining comprehensive coverage through sequential transmission across all sectors.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each sector transmits its pilot signal periodically in its assigned subslot within the HDP opportunity. This periodic, structured transmission pattern ensures that all sectors are covered over time while maintaining clear separation between transmissions, achieving both coverage and interference avoidance.

Inventive Principle:
Principle #19Periodic action

3Reliability

If pilot transmission power is increased, then signal detectability improves, but energy consumption increases

Engineering Contradiction:
Improvepilot signal hearabilityVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

Instead of continuously transmitting at high power, the system transmits pilot signals only during specific HDP opportunities in selected subslots. This partial transmission approach provides sufficient signal strength during active periods while significantly reducing overall energy consumption compared to continuous high-power transmission.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

Pilot signals are transmitted periodically during designated HDP opportunities rather than continuously. This periodic transmission maintains adequate signal hearability during active periods while allowing energy conservation during inactive periods, optimizing the balance between detectability and energy consumption.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP2292045B1Apparatus and method for cell-based highly detectable pilot multiplexing
Publication Date: 2018.11.28 QUALCOMM INC
  • EP2292045B1 patent drawingFigure 1
  • EP2292045B1 patent drawingFigure 2
  • EP2292045B1 patent drawingFigure 3~5

AI summary

An apparatus and method for cell-based highly detectable pilot (HDP) multiplexing comprising determining if an HDP opportunity exists; selecting a subslot within the HDP opportunity for transmission of a HDP signal; and activating more than one sector within a cell for the transmission of the HDP signal.