Optimizing VoLTE Drop in Rural Environments

In rural areas, the VoLTE Drop Rate was observed to be significantly higher than expected, mainly due to cell‑edge
conditions, limited coverage, and discontinuities between frequencies.

Optimizing VoLTE Drop in Rural Environments

In rural areas, the VoLTE Drop Rate was observed to be significantly higher than expected, mainly due to cell‑edge conditions, limited coverage, and discontinuities between frequencies.

Although advanced VoLTE features were properly deployed in the network, it was suspected that certain configurations originally designed for urban environments might be having a negative impact in rural scenarios, where link robustness takes priority over throughput or MOS quality.

The objective was to increase the stability of the VoLTE service, reducing call drops without compromising perceived quality or overloading radio resources

Technical intervention by 3dB consult

3dB consult executed a comprehensive project structured around three main workstreams:

• Multidimensional technical review

The team analyzed the key parameters across 12 functional areas, which included:

a) Multidimensional technical review

This review also included a historical analysis of how these features have evolved since 2017 and how their behavior differs depending on the network environment.

b) Definition of a responsible optimization plan

Only changes with clear potential benefit and low operational risk were prioritized, ensuring:

• Increased link resilience in rural areas
• Efficient use of radio resources
• Alignment between KPIs and actual user experience

The work included, among others:

• Specific adjustments to improve inter‑frequency handovers under degraded conditions
• Activation and tuning of quality‑based mobility mechanisms in downlink, enabling more timely transitions to carriers with better coverage
• Reconfiguration of HARQ parameters to increase tolerance in both UL and DL

Selective adjustments in prescheduling and TTI Bundling to reinforce call continuity in borderline scenarios.

c) Continuous monitoring and comparative analysis

3dB consult conducted daily monitoring of the cluster’s performance, including:

• Comparison of data across different statistical sources
• Trend analysis for pre‑ and post‑configuration periods
• Identification of anomalous behaviors and subsequent calibration adjustments

This approach made it possible to understand the real evolution of the service and validate which functionalities delivered measurable benefit and which required further refinement.

Results

Following the implementation of the prioritized configuration changes, the results exhibited clear and quantifiable improvements:

Approximately an 18% reduction in the VoLTE Drop Rate

(based on a comparison of equivalent pre‑ and post‑implementation periods)

In addition to the overall drop reduction:

• Performance consistency across rural cells improved, reducing discrepancies between similar coverage conditions.
• Inter‑frequency mobility became more stable, with fewer late transitions under degraded radio conditions.
• VoLTE DL Packet Loss and VoIP Integrity showed measurable improvements, driven by the newly activated downlink‑based mobility mechanisms.

Technical and Methodological Learning

This analysis reinforced two fundamental pillars of 3dB consult’s approach:

Responsible Innovation

The study showed that network optimization is not simply a matter of enabling new features, but of adapting them to real‑world conditions.

Configurations that are effective in urban environments do not necessarily maximize performance in rural areas. The key is to make decisions based on actual impact, not theoretical expectations.

Technical Leadership

The work required coordinating specialists, prioritizing actions according to their expected contribution, and managing technical uncertainty through data‑driven evaluation.

It strengthened the team’s ability to:

• Make evidence‑based decisions.
• Balance robustness, quality, and radio‑resource efficiency.
• Translate complex technical analysis into practical, operative actions.