Adaptive Cell Search Frequency Exclusion for Mobile Devices

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Solution Overview

Problem

Current mobile communication systems, particularly 3GPP-compliant systems using WCDMA and GSM radio access technologies, face increased search times and power consumption due to the need to scan all possible frequency bands across different radio access technologies, leading to prolonged battery life reduction and user experience degradation.

Innovation Solution

Implementing an adaptive cell search method where, if a cell is found in a first radio access technology, the search in a second technology excludes specific frequencies based on the found cell's frequency information, reducing unnecessary scans and power consumption by excluding overlapping frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the UE searches for cells across all frequency bands of all supported RATs, then the UE can ensure comprehensive network coverage and service availability, but the search time and power consumption increase significantly

Engineering Contradiction:
Improvenetwork coverageVSAvoidsearch time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary cell search in the first RAT (e.g., WCDMA) before searching in the second RAT (e.g., GSM). The frequency information obtained from the first RAT search is used to pre-identify and exclude overlapping frequencies in the second RAT search, thereby reducing the overall search time while maintaining comprehensive coverage

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent extracts and utilizes frequency information from cells found in the first RAT to identify and remove (exclude) corresponding overlapping frequencies from the search space of the second RAT. This extraction of useful frequency data prevents redundant searching and reduces search time

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If the UE searches for cells across all frequency bands of all supported RATs, then the UE can ensure comprehensive network coverage and service availability, but the power consumption increases

Engineering Contradiction:
Improvenetwork coverageVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system performs preliminary cell search in the first RAT before searching in the second RAT. The frequency information obtained from the first RAT search is used to pre-identify and exclude overlapping frequencies in the second RAT search, thereby reducing the overall power consumption while maintaining comprehensive coverage

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent extracts and utilizes frequency information from cells found in the first RAT to identify and remove (exclude) corresponding overlapping frequencies from the search space of the second RAT. This extraction of useful frequency data prevents redundant searching and reduces power consumption

Inventive Principle:
Principle #2Taking out (Extraction)

3Loss of time

If the UE excludes frequencies based on found cells in one RAT from search in another RAT, then the search time and power consumption are reduced, but the complexity of frequency management increases

Engineering Contradiction:
Improvesearch timeVSAvoidfrequency management
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The patent implements a universal frequency exclusion mechanism that works across different RAT pairs (WCDMA-GSM, GSM-WCDMA, etc.). The same frequency information extraction and exclusion logic is applied regardless of which RAT is searched first, simplifying the overall system design despite the added functionality

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

Solution Approach 2:

The system introduces an intermediary frequency information structure that stores and manages the frequency data from found cells. This intermediary structure facilitates the exclusion process by providing a centralized repository of frequency information that can be efficiently queried and applied across different RAT searches

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2122928B1Data sharing among radio access technologies
Publication Date: 2013.04.10 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP2122928B1 patent drawingFigure 1
  • EP2122928B1 patent drawingFigure 2
  • EP2122928B1 patent drawingFigure 3~4

AI summary

By adapting its search procedures, a user equipment in a mobile communication system can shorten the time needed to find a cell or public land mobile network. If a first cell in a first radio access technology has been found, the equipment can exclude one or more frequencies from a search for cells in a second radio access technology. Thus, time and power are not wasted searching for cells in the second radio access technology that cannot be found.