Femtocell Base Station Interference Management via Priority Carrier

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Solution Overview

Problem

In wireless communication systems, interference from macrocell signals affects femtocell signals, leading to unstable high-speed communication in areas where femtocells and macrocells overlap, making it difficult to completely eliminate interference and maintain stable communication.

Innovation Solution

The system employs a priority CC allocation method, where the femtocell base station designates a priority CC with the lowest frequency for measurement and notification, allowing the mobile station to switch between femtocell-dedicated and common CCs based on interference levels, ensuring stable communication by optimizing CC usage and reducing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If femtocell and macrocell use the same frequency band for communication, then spectrum utilization is improved, but communication stability deteriorates due to interference from macrocell signals

Engineering Contradiction:

Improvespectrum utilizationVSAvoidcommunication stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The frequency band is segmented into priority CC (lowest frequency) for measurement and notification, and other CCs for data transmission. This segmentation allows the system to separate control functions from data functions, enabling stable communication by using the priority CC for interference monitoring and switching decisions while utilizing other CCs for high-speed data transmission.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The mobile station dynamically switches between femtocell-dedicated CC and common CC based on measured interference levels. The system continuously monitors the priority CC and adjusts the active communication CCs in real-time, transforming the static frequency allocation into a dynamic adaptive system that responds to changing interference conditions.

Inventive Principle:

Principle #15Dynamics

2Speed

If femtocell uses broadband continuous frequency domain for LTE-A, then communication speed is improved, but interference from macrocell signal increases in overlapping areas

Engineering Contradiction:

Improvecommunication speedVSAvoidinterference from macrocell signal

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

Different quality requirements are applied to different frequency resources. The priority CC (lowest frequency) is used with high reliability for control signaling and measurement, while other CCs are used for data transmission with higher speed requirements. This local quality differentiation allows the system to maintain stable control functions even when data transmission experiences interference.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The priority CC acts as an intermediary channel that mediates between the mobile station and the network for control purposes. By using this dedicated intermediary for measurement and notification, the system can make informed decisions about which CCs to use for high-speed data transmission, thereby managing interference while maintaining communication speed.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If mobile station monitors all common CCs for interference, then communication stability is improved, but power consumption increases

Engineering Contradiction:

Improvecommunication stabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The measurement and monitoring function is extracted from all common CCs and concentrated only in the priority CC (lowest frequency). This extraction allows the mobile station to perform interference monitoring with reduced power consumption while still maintaining the ability to detect interference conditions that would affect data transmission on other CCs.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The priority CC serves multiple functions: it is used for measurement, for notification of interference conditions, and as a fallback communication channel. This multi-functionality reduces the need for separate dedicated measurement channels and allows the system to maintain stability monitoring while conserving power by consolidating functions into a single CC.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentEP2525596B1Wireless communication system, base station apparatus, mobile station apparatus, communication control method, and communication control program

Publication Date: 2019.12.25 SHARP KK

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AI summary

A mobile station apparatus can stably communicate with a base station apparatus even when interference occurs due to a signal from another apparatus in a part of a frequency band used for communication. A second base station apparatus communicates with the mobile station apparatus using a common frequency band, which is all or part of a frequency band to be used for communication by the first base station apparatus, and a dedicated frequency band to be unused by the first base station apparatus. A communication band selection unit a256 of the second base station apparatus selects the common frequency band as a frequency band to be used for communication with the mobile station apparatus in case that radio quality of the common frequency band in the mobile station apparatus is greater than a predetermined threshold value, and selects the dedicated frequency band as the frequency band to be used for the communication with the mobile station apparatus in case that the radio quality of the common frequency band in the mobile station apparatus is less than the predetermined threshold value.