Femtocell Low Duty Cycle Pattern Broadcasting

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Solution Overview

Problem

Femtocells in dense deployments experience interference with each other and macro cells, leading to inefficient power usage and scanning challenges in Low Duty Cycle (LDC) mode, where femtocells alternate between active and inactive periods, making it difficult for mobile stations to efficiently search for available femtocells.

Innovation Solution

Defining and broadcasting Low Duty Cycle patterns with specific Available and Unavailable Intervals, along with a Start Offset, to mobile stations, allowing them to efficiently scan and identify active periods of femtocells, thereby reducing interference and conserving battery life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If femtocells operate in Low Duty Cycle mode with alternating active and inactive periods, then power consumption is reduced and interference to macro cells is minimized, but mobile stations face difficulty in efficiently scanning and identifying available femtocells

Engineering Contradiction:

Improvepower consumptionVSAvoidscanning difficulty

Core Design Contradiction:

Loss of energyVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies preliminary action by having the femtocell base station broadcast Low Duty Cycle pattern information (including Available Interval, Unavailable Interval, and Start Offset) before the mobile station attempts to scan. This advance notification enables the mobile station to efficiently schedule its scanning activities during Active Intervals without having to continuously monitor or guess when the femtocell will be available, thus reducing scanning difficulty while maintaining power savings.

Inventive Principle:

Principle #10Preliminary action

2Ease of operation

If femtocells continuously broadcast system information and preambles, then mobile stations can easily discover and connect to femtocells, but interference with macro cells and other femtocells increases and power is wasted

Engineering Contradiction:

Improvediscovery easeVSAvoidinterference

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent applies periodic action by implementing Low Duty Cycle operation where the femtocell base station alternates between Active Intervals (when it broadcasts preambles and system information) and Unavailable Intervals (when it shuts down transmissions). This periodic operation reduces interference and power consumption compared to continuous broadcasting, while still enabling mobile station discovery during the Active Intervals. The pattern information is broadcast to ensure mobile stations can synchronize with these periodic transmissions.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentEP2471299B1Method and system for efficient support low duty mode in femtocells

Publication Date: 2020.05.27 SAMSUNG ELECTRONICS CO LTD

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AI summary

A method and system for handling working of a Low Duty Cycle (LDC) mode of one or more Base Stations (BS) in a wireless communication network. The method includes defining one or more LDC patterns based plurality of LDC parameters associated with one or more BS where the plurality of LDC parameters includes an active period, an inactive period and a start frame offset of the one or more BS in the wireless communication network. The method then sends the one or more LDC patterns notifying Available Interval and Unavailable Interval of each of the one or more patterns to a Mobile Station (MS) by broadcasting one or more LDC patterns, unicasting the one or more LDC pattern to the MS, multicasting the one or more LDC pattern to a group of MSs or send the one or more LDC patterns to one or more MS in a pre-provisioned way.