# Mapping the telecom data landscape beyond the CDR
A single 4G voice call can generate more than a dozen separate data records across a carrier's systems: a Call Detail Record (CDR) in billing, a session log on the Mobility Management Entity, a QoS (Quality of Service) trace on the radio controller, a roaming record if the subscriber is abroad, and a customer care note if the call dropped and the subscriber complained. Most telecom analytics training stops at the CDR. That is like studying a bank by only reading receipts. This lesson maps the fuller data estate: where it lives, who owns it, and where it quietly breaks.
The CDR (Call Detail Record) captures the metadatametadataDonnées sur les données, informations décrivant le contexte, la structure, la provenance et les caractéristiques d'un asset de données (auteur, date, format, source, définition). of a voice call or SMS: caller, callee, duration, timestamp, cell tower. It is the historical backbone of telecom billing and fraud detection. For data (packet) sessions, the equivalent is the xDR or IPDR (Internet Protocol Detail Record).
But CDRs answer only "what happened on the network." They cannot tell you why a customer churned, whether a SIM was ever activated, or if a roaming partner is overbilling you. For that, you need the rest of the stack.
OSS (Operations Support Systems) manage the physical and logical network: inventory of base stations, fiber routes, spectrum allocation, fault and performance management. Key datasets:
These feed capacity planning, capital expenditurecapital expenditureCapital Expenditure (CapEx) is money spent to acquire, upgrade, or extend long-lived assets like equipment, property, or software that deliver value over multiple years.Voir la définition complète → prioritization, and network health dashboards. Hidden gap: PM counters are vendor-specific (Ericsson, Nokia, Huawei all format differently), so consolidating a multi-vendor network requires a normalization layer, often the single biggest hidden cost in a network data warehousedata warehouseA central repository that consolidates data from many source systems into a structured, query-optimized store designed for analytics, reporting, and business intelligence.Voir la définition complète → project.
BSS (Business Support Systems) run the commercial side: customer relationship managementcustomer relationship managementCustomer Relationship Management: software and strategy to manage and analyse customer interactions throughout their lifecycle.Voir la définition complète →, billing, order management, product catalog. Key datasets:
This is the primary feed for churn models, average revenue per user (ARPU) reporting, and customer lifetime valuecustomer lifetime valueLifetime Value: the total revenue (or profit) a customer generates throughout their entire relationship with your business.Voir la définition complète → work. Hidden duplication: the same subscriber often exists as multiple records across prepaid, postpaid, and IoT (Internet of Things) systems inherited from mergers, a classic source of double-counted subscriber bases in KPIKPIKey Performance Indicator, a measurable value that shows how effectively you're achieving a specific objective, tracked over time against a target.Voir la définition complète → reporting.
Below OSS aggregates sit raw logs from routers, switches, and radio equipment: signaling protocol traces (e.g., Diameter, SIP), deep packet inspection samples, and security event logs. These are voluminous (often petabytes per month for a national carrier) and rarely stored longer than days or weeks due to cost. They matter for root-cause analysis of outages and for training network AI/ML models (e.g., anomaly detection for self-organizing networks). Most of this data is generated and discarded before anyone outside network engineering ever sees it, a genuine visibility gap for commercial teams.
When a subscriber uses a network abroad, the visited network sends usage data back to the home carrier for billing and fraud checks, via two GSMA (GSM Association) standards:
Why this matters: roaming fraud and billing disputes between carriers run into real money industry-wide, and TAP/NRTRDE reconciliation is one of the more manual, error-prone data processes in telecom because it depends on dozens of bilateral partner formats. Reference: GSMA's public roaming and fraud resources outline the operational standards.
Mismatches between the SIM registry and the BSS subscriber master are a classic audit finding: a SIM can be technically active on the network while billing systems mark the account as churned, inflating "active subscriber" counts if not reconciled.
Call center transcripts, chat logs, and social media mentions are unstructured but increasingly mined for churn prediction, sentiment analysis, and Net Promoter ScoreNet Promoter ScoreNet Promoter Score (NPS) measures customer loyalty by asking how likely customers are to recommend a brand, then subtracting detractors from promoters.Voir la définition complète → (NPSNPSNet Promoter Score (NPS) measures customer loyalty by asking how likely customers are to recommend a brand, then subtracting detractors from promoters.Voir la définition complète →) diagnostics. This is the fastest-growing data category in telecom because of generative AI use cases, but it carries the highest privacy sensitivity and typically the least mature governance.
| Failure pattern | Typical cause | Business impact |
|---|---|---|
| Duplicate subscriber records | M&A system migrations, prepaid/postpaid silos | Overstated subscriber KPIs |
| Orphaned SIMs | SIM active in HLR, absent from billing | Revenue leakage |
| Roaming file mismatches | Partner format drift, timezone errors | Billing disputes, fraud blind spots |
| PM counter gaps | Vendor outage, clock drift | Understated network problems |
| Unlinked care transcripts | No common customer ID across channels | Missed churn signals |
Suppose a carrier's BSS reports 22.4 million active subscribers, but the HLR/HSS shows 21.1 million unique active SIM identities (IMSIs) over the same billing cycle (illustrative figures for this exercise, not a real carrier's reported numbers).
Duplication estimate = (BSS active count − HLR unique IMSI count) / BSS active count
= (22.4M − 21.1M) / 22.4M
= 1.3M / 22.4M
≈ 5.8%A gap this size, roughly 5.8%, is a governance red flag worth investigating before the number reaches an investor or regulatory report. It usually traces back to churned accounts not deprovisioned in the network, or duplicate accounts from a system migration.
Vérification des acquis
1. Why does the lesson argue that CDRs alone are insufficient for a full telecom analytics picture?
2. A single voice call can generate over a dozen separate records across different systems. What is the main analytical implication of this?
3. What is the primary role of OSS (Operations Support Systems) data in the telecom data landscape?
4. Select ALL correct answers about Performance Management (PM) counters in OSS.
Sélectionnez toutes les réponses correctes.
5. Select ALL correct answers about records generated beyond the CDR for a single call.
Sélectionnez toutes les réponses correctes.
European carriers operate under GDPR (General Data Protection Regulation), which mandates data minimization and a lawful basis for processing customer and location data; the relevant enforcement bodies are national Data Protection Authorities (e.g., CNIL in France, ICO in the UK, though the UK runs a parallel UK GDPR post-Brexit). In the US, telecom customer data (CPNI, Customer Proprietary Network Information) is governed by FCC (Federal Communications Commission) rules under the Communications Act, with state-level privacy laws (like California's CCPA/CPRA) adding further obligations.
Good practice, seen at leading operators, assigns a data owner per domain (network, billing, customer care) plus a cross-functional data governancedata governanceData governance is the set of policies, roles, and processes that ensure data is accurate, secure, well-defined, and used responsibly across an organization.Voir la définition complète → council that owns the master customer ID linking all systems together. Without that master ID, every cross-domain analysis (like the subscriber duplication check above) requires a manual, ad hoc reconciliation.
🎬 [VIDEO: "What is a CDR (Call Detail Record)?" - youtube.com - search for TechTarget or telecom-vendor explainer channels covering CDR structure and use in billing and fraud detection]