Tech Mahindra helps BelgianTelecom cut CAT Defects by 76% through Engineering Excellence

Overview

A leading Belgian telecommunications provider faced significant challenges in maintaining process compliance and engineering best practices across its B2B and B2C programs. A weak Unit and System Testing (ST) approach and high defect density in Combined Acceptance Testing (CAT) impacted release quality and customer satisfaction.More

A leading Belgian telecommunications provider faced significant challenges in maintaining process compliance and engineering best practices across its B2B and B2C programs. A weak Unit and System Testing (ST) approach and high defect density in Combined Acceptance Testing (CAT) impacted release quality and customer satisfaction. To address these issues, Tech Mahindra introduced structured quality gates, strengthened engineering governance, and enforced automated code quality checks. This strategic intervention improved release stability, improved stakeholder confidence, and delivered measurable improvements in delivery quality.

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Business Challenges

A leading telecommunications provider headquartered in Brussels operates across both B2B and B2C segments. Given the scale of their operations, the client faced significant challenges, including:

  • Ensuring strong engineering discipline and process compliance across multiple delivery programs.
  • Addressing weak Unit, ST, and System Integration Testing (SIT) practices, causing high Field Defect Density (FDD) and defect seepage into Combined Acceptance Testing (CAT).
  • Managing Service Level Agreement (SLA) and Key Performance Indicators (KPIs) while preventing release risks following a No-Go decision for a major 2025 rollout.

Our Approach and Solution

We partnered with the client to enhance engineering quality and strengthen delivery governance across B2B and B2C programs. The approach included:

Quality Gate (QG) Checklist

Established a comprehensive release-level QG framework with customized checkpoints to ensure engineering rigor and compliance before each deployment stage.

Domain-wide Assurance Coverage

Sampled 30% of components across all domains to validate quality standards and reduce defect seepage into later test phases.

Automation-Led Code Quality Enforcement

Mandated automated code analysis using SonarQube, improving early defect detection and enhancing coding discipline.

Centralized Action Traceability

Utilized JIRA and Confluence for seamless action tracking, transparency, and continuous improvement across stakeholder teams.

Root Cause-Driven Defect Analysis

Introduced structured defect categorization and “5 Why” analysis to eliminate repeat issues and uplift testing maturity during ST, SIT, and CAT.

Business and Community Impact

The transformation delivered measurable improvement in release quality and delivery confidence:

  • Restored Release Confidence: The customer granted approvals for the March 2025 (R03-25) rollout and subsequent releases. They expressed appreciation for the implementation of new ways of working and the incorporation of checkpoints that addressed systemic issues.
  • Significant Quality Improvement: A 76% reduction in CAT defect density was achieved from June 2024 (R06-24) to April 2025 (R04-25), minimizing defect seepage and strengthening testing outcomes.
  • Implemented Release-Level Engineering Checks: The Quality Control (QC) team implemented structured release-level engineering checks to ensure the quality of deliverables, strengthening validation processes across ST, SIT, and CAT phases.
  • Stronger Operational Performance: Improved adherence to SLAs and KPIs, enhancing the Quality Index.
  • Business Continuity and Trust: Increased confidence in predictable delivery enabled a two-year contract extension, without initiating a formal Request for Proposal (RFP).