CSFB KPI Measurement via Cross-RAT Log Correlation
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Solution Overview
Problem
Current methods for determining Key Performance Indicators (KPIs) for Circuit-Switched Fall-back (CSFB) and Single Radio Voice Call Continuity (SRVCC) calls between different Radio Access Technologies (RATs) are limited by the lack of feedback mechanisms, making it difficult to accurately assess call success rates and setup times, especially since drive tests only capture outdoor performance and do not provide visibility into core network issues.
Innovation Solution
A method that extracts and merges cell trace data from both the first RAT (e.g., LTE) and second RAT (e.g., WCDMA) to calculate KPIs such as CSFB/SRVCC and Inter RAT KPIs by using network nodes to filter and correlate session information from logs associated with each RAT, enabling the determination of Call Success Rate and Call Setup Time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If drive test based testing is used to capture CSFB/SRVCC KPIs, then outdoor performance can be measured, but time and cost increase and core network issues cannot be detected
Solution Approach 1:
The patent introduces a data correlation system that acts as an intermediary between drive test data and core network logs. This system automatically matches and correlates data from multiple sources (drive tests, core network logs, radio access network logs) using identifiers like IMSI, MSISDN, and timestamps, eliminating the need for manual data processing and enabling comprehensive KPI measurement without additional time cost
Solution Approach 2:
The patent merges data from multiple previously separate sources (drive test data, core network logs, radio access network logs) into a unified analysis framework. By combining these data sources and correlating them through unique identifiers, the system achieves comprehensive KPI measurement that includes both outdoor performance and core network issues simultaneously
2Measurement precision
If drive test based testing is used to capture CSFB/SRVCC KPIs, then outdoor performance can be measured, but cost increases
Solution Approach 1:
The patent enables the network to self-measure and self-diagnose KPIs by automatically correlating existing log data from core network and radio access network with drive test data. This automated self-service approach eliminates the need for expensive manual drive test campaigns, as the system can independently extract and analyze the required KPI information from available network data
3Difficulty of detecting and measuring
If drive test data is used for troubleshooting, then layer 3 messages over air interface can be analyzed, but core network interface issues remain undetected
Solution Approach 1:
The patent merges drive test data containing layer 3 message information with core network logs containing interface level information. By correlating these data sources through unique identifiers, the system simultaneously provides both air interface analysis and core network visibility, eliminating the information loss that occurred when using drive test data alone
4Device complexity
If no feedback mechanisms are implemented in LTE to 3G handover, then system complexity is reduced, but visibility after UE release is lost
Solution Approach 1:
The patent implements a feedback mechanism by correlating handover events in LTE with corresponding events in 3G networks through data matching. Although no direct feedback messages are sent during handover, the system creates virtual feedback by matching UE identifiers and timestamps across networks, enabling post-release visibility without adding complexity to the actual handover process
Data Source
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AI summary
The present disclosure relates to a method of obtaining at least one Key Performance Indicator (KPI) for a communication session (11) of a radio device (2). The communication session is moved from a first Radio Access Technology (RAT) (3a) to a second RAT (3b). The method comprises extracting first information about the communication session from at least a first log associated with the first RAT by filtering information relating to communication sessions which have moved between RATs from other communication sessions in the first log. The first information comprises a session identifier (ID) and a first time stamp associated with the communication session. The method also comprises extracting second information about the communication session from a second log associated with the second RAT by filtering information relating to communication sessions which have moved between RATs from other communication sessions in the second log. The first information comprises the session ID and a second time stamp associated with the communication session. The method also comprises merging the extracted first and second information with each other by means of the session ID and the first and second time stamps. The method also comprise determining the at least one KPI for the communication session based on the merged information.