Call Detail Record

A Call Detail Record (CDR) (also Call Detail Recording) or Station Message Detail Recording (SMDR) in the telecom sector is a file containing information about recent system usage such as the identities of sources (points of origin), the identities of destinations (endpoints), the duration of each call, the amount billed for each call, the total usage time in the billing period, the total free time remaining in the billing period, and the running total charged during the billing period. The format of the CDR varies among telecom providers or programs. Some programs allow CDRs to be configured by the user.

A CDR for a particular account can be downloaded at the request of the subscriber who holds that account. If the telecom provider supplies users with itemized bills, a CDR will show up in each bill, in a format similar to that of an itemized long-distance telephone bill supplied by a conventional telephone company.

In a telephone exchange, a CDR contains information about all the calls passing through the exchange. The CDRs are generated by Automatic Message Accounting (AMA) and processed by the operations support system (OSS).

A CDR File may contain more than one type of call traffic. For example, fixed line voice traffic and fixed line data traffic may be placed in the same file, but will be identified separately for rating purposes.

Call accounting software or communication management software is generally used to retrieve and process CDR data.

EMC and Intec and Sensage Technology to Identify Terrorist Activity in Call Detail Records

EMC Corporation (NYSE: EMC), Intec Telecom Systems (LSE: ITL.L) and SenSage, Inc. have pooled their resources to provide a comprehensive, cost effective solution to answer the mandates of the EU Data Retention Directive. The combined technologies tackle two issues. First, it provides telecommunication and Internet service providers with a lower cost means to manage communication records that support compliance with the Directive. Second, it enables law enforcement agencies to quickly access historical phone and Internet records to pinpoint and prosecute terrorist activity and other serious crime. The Directive states that all service providers must be compliant by August, 2007.

The EU Data Retention Directive was announced in March 2006. It requires telecommunications operators (Telcos) and Internet Service Providers (ISPs) to securely retain and be able to analyse traffic and location data related to; fixed telephony; mobile telephony; Internet access; Internet e-mail; and Internet telephony for up to two years. The Directive further requires that all service providers must produce answers to law enforcement inquiries without any undue delay. Millions of calls and connections occur each day equating to billions of records and terabytes of transaction data that must be securely stored and rapidly analysed.

EMC, Intec Telecom Systems and SenSage have developed a joint EU Data Retention solution that significantly reduces the cost of compliant data management for service providers. The combined technology completely supports the guidelines set out by the Directive and is able to cost-effectively manage and obtain results in minutes from over 100 billion Call Detail Records (CDR).

“The EU Data Retention Directive puts tremendous pressure and a clear timeline on Telcos and ISPS to meet security and investigation obligations,” said Fernando Elizalde, senior telecommunications analyst at Frost & Sullivan. “The newly developed technology offered by EMC, Intec Telecom Systems and SenSage supports the Directive mandates by providing a progressive, scalable platform, to cost-effectively manage the broad event data integration, storage and analysis requisites.”

“Telcos and ISPs will have to make significant changes to procedure, operations and current technologies if they are to meet the EU Data Retention and Privacy Directives,” said Terje Tondel, managing director of ETIS.org – the largest global IT association for telecommunication providers. “Our constituents have been advised to assess current resources and seek innovative solutions, such as that from EMC, Intec Telecom Systems and SenSage, which can minimise costs and expedite results that address these guidelines”.

The joint solution has been fully tested with sample CDR data from a leading telecommunications provider. The sample data, collected and processed through an Intec mediation platform, was cleansed, then subsequently randomised and replicated to generate the necessary volume. SenSage provides the scalable event data management platform that powers the collection, compression, management and high-speed analysis of the CDR data. Retention and online availability of the stored data is fully managed within an EMC Centeraâ„¢ storage cluster, which provides increased data integrity, protection, and availability capabilities. Intec Telecom Systems provided switch remediation expertise and design guidance. The Proof-of-Concept (POC) contains 100 billion records, representing 13 terabytes of raw compressed data. It is now maintained in an online, referenceable repository where complex analytics can quickly be performed to investigate criminal activity.

“The EU Data Retention directive increases the cost of doing business for Telco’s and ISP,” said Jim Pflaging, president and CEO of SenSage. “This joint solution offers the rapid response law enforcement needs in a highly secure system the public wants, at the lowest cost to the service provider.”

The joint PoC simulated retention of two years of CDR data of 10 million Telco subscribers. The system executed un-indexed queries at more than 27.9 million records per second and obtained answers in less than seven minutes within a three month search range. The combined solution achieved these results at a fraction of the overall cost when compared to that of conventional approaches, which rely on relational database management technologies and data archives. Detailed test results and estimates of cost can be found at http://www.sensage.com/eudrpoc.

Mark Thurmond, general manager of EMC Centera Division commented: “Being able to quickly and efficiently search massive amounts of data is pivotal to compliance with this EU directive. Without the storage capabilities to retain and manage that data, companies simply would not be able to achieve compliance, but working with SenSage means that organisations can choose a complete easy to use solution.”

The EU Data Retention technology is comprised of the SenSage scalable event data management platform, pre-defined reports that support directive guidelines and EMC Centera content addressable storage (CAS) to yield a high-performing, extensible and secure information lifecycle technology. SenSage is an EMC Centera Proven solution that transparently integrates with EMC Centera for fast, easy online data access with assured content authenticity and petabyte scalability. This product can be predictably expanded to meet varying Telco telephony, IP and messaging sources, data volumes and implementation requirements at the lowest cost.

The joint SenSage/EMC/Intec solution POC, housed in the EMC labs in Cork, Ireland, has been made possible by the efforts of a number of EMC Technology partners. The SenSage event data management platform leveraged leading edge technologies from Dell™ with their new range of Dual Core, Dual CPU PowerEdge™ 2950 servers containing the latest Intel® Xeon® 5160 “Woodcrest” processors and the latest 64-Bit version of RedHat® Enterprise Server 4. When coupled with the EMC Centera Content Addressed Storage via Cisco Catalyst 3750 high performance switch, the overall architecture provides the most price-performing solution stack to the issue of collecting, storing and analysing the vast amount of data required by the EU directive.

Peter Deane Managing Director of Intec’s EMEA operation added, “The solution provided by SenSage and EMC complements Intec’s experience in offering mediation and billing system technologies and services. We believe the three pronged combination of cost savings, manageability and scalability provides a compelling value proposition.”

“Telecom operators and ISPs will have to significantly enhance and broaden their data retention policies to adhere to the Directive – assuring adequate protection and guaranteeing that authorities can receive results to their queries in due time,” said Dr. Patrick Van Eecke, counsel and head of the Internet law group at DLA Piper Rudnick Gray Caryk UK LLP, Brussels. “DLA Piper asserts that the functionality offered by storage products, such as EMC Centera, and high performance event analysis solutions, such as SenSage, are indispensable in reaching these goals.”

About SenSage
SenSage Inc., the leading provider of scalable event data management solutions, empowers companies to readily respond to business-critical threats, conduct thorough and precise investigations, and maintain compliant operations. The company offers unparalleled performance and a scalable means for organizations to centrally aggregate, efficiently analyze, dynamically monitor and cost-effectively store massive volumes of event data. Based in San Francisco, CA, SenSage currently protects Global 2000 customers in financial services, government, healthcare, retail, manufacturing, telecommunications and technology. The company markets its product directly and through partners including Cerner, EMC, Hewlett-Packard, IBM, Sendmail, Tokyo Electron and Lockheed Martin. For more information, visit www.sensage.com.

About EMC Corporation
EMC Corporation (NYSE: EMC) is the world leader in products, services and solutions for information management and storage that help organizations extract the maximum value from their information, at the lowest total cost, across every point in the information lifecycle. Information about EMC’s products and services can be found at www.EMC.com.

EMC is a registered trademark and Centera is a trademark of EMC Corporation. All other trademarks are the property of their respective holders.

About Intec Telecom Systems
Intec (LSE: ITL.L) supplies billing software solutions to over 60% of the world’s top 100 telecoms carriers and is one of the world’s fastest growing BSS/OSS (business and operations support systems) vendors. Intec’s 400 customers include BellSouth Telecommunications Inc., Cable & Wireless, The Carphone Warehouse (UK), China Unicom, Deutsche Telekom, Vodafone, Virgin Mobile, Vivo and Verizon. For more information, visit the Intec website at www.intecbilling.com.

All names and marks referenced herein are the property of their respective owners.

Spatial Analysis of GSM Subscriber Call Data Records

Spatial Analysis of GSM Subscriber Call Data Records

By Ireti Ajala , MTN Nigeria Communication Ltd.
March 07, 2006

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The Experience of MTN Nigeria

The most valuable asset of many companies is not their products or services, but their data. This is particularly true in the communications industry. Trapped inside the customer billing systems is a gold mine of data that holds the key to customer retention, reduced expenses, customer self-service and overall competitive advantage.

In the mobile communications networks, the core business is selling airtime to subscribers. All the information about that airtime is tracked through call data records, or CDRs. CDRs are used to bill customers. Because of the huge amount of data that would need to be processed, they are usually not analyzed to add business value. However, with shrinking margins and increasing pressure to improve revenues, operators now are looking closely at ways to use these data to their advantage.

GIS is one powerful tool that can be used to analyze CDRs, allowing the operators to see a precise, up-to-date picture of the entire network and to better understand the calling patterns of their subscribers, with a view to knowing their networks better and offering subscribers customized services, and hence increasing revenue.

This article describes how MTN Nigeria has been using GIS to investigate the relationship between the geographic spread of subscribers, using CDRs and network stipulated key performance indicators (KPIs) like traffic.

A CDR is generated at the switching center of a GSM network each time a successful call goes through. The switching center generates huge volumes of these records, sometimes running into terabytes. It is therefore a serious challenge to analyze these raw data to enhance the making of informed decisions.

CDRs can be analyzed based on the location of subscribers, cells, market share, handset usage, etc. Unlike other network monitoring statistical analyses that attempt to analyze the network purely from radio or engineering points of view, CDRs are analyzed principally from the subscribers’ points of view, and we use GIS to do this. In telecommunications, “where” is everything, which is why GIS is a very useful tool in telecommunication – more than half of all decisions made in telecommunications are geographic in nature.

GIS and CDR Analysis
Using a map to analyze CDR data can provide a dramatic improvement over traditional row-column methods, allowing operators to see a precise, up-to-date picture of the entire network, and visually identify the location of subscribers, or the most profitable cell in the network in terms of the amount of time spent originating calls.

Some time ago at MTN Nigeria, we undertook to understand the geographic spread of our subscribers based on their most used cell during working hours over a period of one month. We knew that the engineering network-monitoring tool could achieve this, but we were interested in looking at this issue strictly from a subscriber’s point of view, and hence we decided to use CDRs for this analysis. By looking at CDRs, we can understand activity per customer.

We were particularly interested in understanding the geographic areas within our network where there exists a correlation between subscribers and traffic generated. This became important to us because it was noted that some places have large numbers of subscribers but generate only relatively smaller amounts of traffic compared to other places. From our previous studies of our network, we have come to understand the fact that the number of subscribers in most places is not necessarily proportional to the amount of traffic generated; however some areas within our network are exceptional. This new study will help us to continue to locate these exceptional places, as they portend huge sources of revenue for us.

To achieve this goal of this study, we decided to produce two maps to do a comparative analysis – one map showed the geographic spread of our subscribers and the other showed the geographic spread of traffic generated across the network for the same area. We believed that overlaying these two maps would give us a tool that would help us better size our network.

The data requirements for this analysis are as follows. Each is described below.

1. Summary CDR data
2. Equal Power Boundary Areas (EQBAs) or predicted coverage arrays
3. Vector map layers

Summary CDR
The CDR server architecture differs from one operator to the other depending on the CDR analyzing application used (see Fig. 1). At MTN, an Oracle 9i database is used for this purpose. It provides a very flexible architecture for data storage and access.

The database can be accessed in real-time using an application server, or queried by customer applications such as a billing system, or accessed by a reporting tool such as FACTS Reports. A listener application (a set of tools that allow the operator to pull data directly from the database) is co-hosted with the database server running on the data layer. It collects the data posted by the probes and then updates the database using the collected data

The raw CDRs generated at the switch are called the Toll Ticket File, or TT File for short, and are processed into summarized CDR tables. These summary tables make it possible to aggregate all activities on the basis of the serving cell. It is therefore possible to give a figure for the total number of subscribers and the hours spent on each cell. We accumulated the summarized CDRs generated over a one month period based on subscribers’ most used cells during the working hours and their most used cells during non-working hours.

These data formed the basis for the attribute table required for the GIS application. Table 1 (below) is a sample of the result of a query to find the number of subscribers making calls using each cell as their most used cell over a period of one month and the amount of time spent originating calls.

EQBAs or predicted coverage arrays
EQBAs are geo-referenced polygons that represent the radial distance of the signal from the serving cell, based on radio’s interaction with the environment. The planning tool combines a number of coverage predictions into a raster surface, which contains the best coverage values for each location, as well as other information regarding the serving cell. The EQBAs formed the spatial layer used for this particular application.

Vector map layers
Vector layers like city street maps and point location layers were used to further track subscriber behavioral patterns down to the micro level. These helped us to associate geographic areas to the aggregated CDR tables and further helped in understanding what was happening where (see Fig. 3).

Since this analysis used data from a period of one month, it was not necessary to create dynamic maps that showed subscribers’ movement patterns every hour.

The key to joining the EQBAs with the CDR Summary table is the “cell ID.” The cell ID uniquely identifies each EQBA polygon, and is used in the CDR table as well. It was used as the primary key to join the two databases using a simple SQL script. Once this joining had been accomplished, a thematic map, based on realistic range categories, was created that gave insight into the geographic spread of subscribers (see Fig. 3)

The map below (Fig. 4) was produced in September 2005 to show the geographic spread of our subscribers across the Lagos metropolis during working hours. The darker the patch, the more concentrated the subscribers around that particular area.

A similar map (see Fig. 5) was produced for the same area based on call traffic generated. When this traffic was compared with the subscriber thematic map, it was interesting to note that in some cases, the number of subscribers was directly proportional to the amount of traffic generated; examples of such places are Alaba International Market and Victoria Island. This makes sense, because Victoria Island is the economic capital of corporate Lagos, while Alaba is one of the most important commercial centers in West Africa, where people come from different parts of Africa to buy both household and industrial electrical appliances. We also noticed a common patch at Ajah, which is becoming one of the fastest growing suburbs in Nigeria. It is estimated that a new house is occupied in Ajah every four hours, and this has been going on for the past three years. We were really excited by this result as it showed that for certain areas in Lagos, a high concentration of subscribes did indeed yield high traffic. However, we wondered if we could assume this condition applied everywhere in Lagos. From the study, we further discovered that in most places, this rule of thumb was not applicable. We thus learned that we couldn’t assume this general rule – many subscribers equals high traffic – applies to the entire network; we would have to take each area on an individual basis.

We were really excited by the result of this analysis and thought it would be interesting to compare the map of calling congestion with the geographic spread of subscribers to see if a large concentration of subscribers had lead to congestion. The result of this second analysis was quite interesting because a large chunk of signaling network resource is usually wasted on a phenomenon called “flash.” A flash, as commonly used in Nigeria, describes a situation whereby a subscriber initiates a call and quickly cuts it before the called party can actually pick it up. People use “flashing” to tell the person they’re calling, “Hey, I am trying to call you but I do not have enough credit to call, so could you please call me?” Most times, the called party will usually respond by calling. So flashing does not last for more than a few seconds but it does rob subscribers who want to make legitimate use of network resources. We discovered that incidents of congestion usually happened where there was a large subscriber base. However, we also discovered that, as simple as this analysis was, we still could not assume it applied everywhere in the network – like the first analysis, we learned we need to take each geographic location on an individual basis.

The above are just two examples in which we have been using GIS to analyze CDRs to our advantage. We have also used the combination of GIS and CDRs as a marketing tool (gathering business intelligence about competitors), network resource dimensioning tool, revenue assurance tool, handset performance and penetration analysis tool, a site selection tool (siting customer care centers), and a routing tool, to mention just a few applications. Comparing the analysis from CDR with other Engineering network monitoring statistics can provide a dramatic assistance to the operator in understanding the network better, with a view to providing unprecedented quality service to the subscribers. This can constitute the leading edge in a highly competitive industry such as the telecommunication industry.

Caveat
The views contained in this article are not those of MTN Nigeria Communications Limited or those of its Management or Board of Directors.

Reference
Ernest C.A. Ndukwe (Nigeria Communication Commission’s Executive Vice Chairman -2004) Welcome Address at the commissioning of the Digital Bridge Institute, Utako.

Sue Marek (2004) Plugging Revenue Leaks.

A Communication Data Storage (Intellectual Property Digital Library)

Surveyor Product Overview (CDR Analyzer –from GL Communication Inc.

CDRLive Product Overview (A CDR Analysis and Warehousing application from LGR Telecoms)

P.A. Burrough (1993) Principles of Geographical Information Systems for Land Resources Assessment

Ireti Ajala (2005) GIS and GSM Network Quality Monitoring: A Nigerian Case Study

Ireti Ajala (2003) The role of GIS in business decision making process of locating Customer Care Centers using GSM subscriber distribution analysis

Ireti Ajala (2003) GIS – A decision making tool – The Experience of MTN Nigeria

Your Comments Post a comment All comments provided in this section are those of the individual who has created the post. These are not the opinions of Directions Media, its editors, staff or owners unless otherwise noted. Directions Media retains the right to edit or delete any comments posted herein.

Apprciation (#1) by Adetunji Adebayo, Spatial Decision Solutions Ltd     Date: March 17, 2006 19:25 PM

I found this article quite interesting. I never thought even for a second that your company uses GIS this much. This is great. However, i was just wondering, what role population density analysis plays in further analysis of CDRs. Again, how does MTN use demographic data in your roll out initatives? I will be interested in finding out other ways you have been using GIS in a GSM environment. Thanks for sharing this article.

outside the technical details (#2) by temitope osho, apbe trade& logistics     Date: March 22, 2006 01:44 AM

I have read with interest this beautiful piece of analysis. But i am less convinced about MTN and its social responsibities to the Nigerian commmunity. It is Sad daily that MTN which is an Advance technological endowed company would profit from sales carried out by kids hawking, obstructive traffic sun beaten youth, and the desguised unemployment umbrella shades. where a nigerian proudly holds a phone he cannot make a call with. Using a strange number for GSM link with another with his phone in his pocket.

Spatial Analysis (#3) by Onyewuchi Obirieze, GeoHealth & Solutions Consultants     Date: April 19, 2006 11:57 AM

Ireti, I welcome your emphasis that core business is underpinned by data. I am equally impressed that you and your team have mobilised resources to capture and format data for both legacy and reusable delivery. Map is a powerful tool for decision at all levels especially for users. GIS/geospatial analysis is one way of bringing expectation, decision and implementation together. You have sold data and knowledge excellently. This is an interesting news!

Responding to Onyewuchi Obirieze’s mail (#4) by Ireti Ajala, MTN Nig     Date: May 5, 2006 03:22 AM

Thanks. We will continue to research into how GIS can be used in other areas to help us make informed technical and business decisions especially in our field. Thanks so much once again

Responding to Temitope Osho’s mail (#5) by Ireti Ajala, MTN Nig.     Date: May 5, 2006 03:37 AM

I am glad that you read the article with interest. I am not in position to answer some of the issues you raised regarding MTN’s social resposibiltes since i am just a technical specialist, but i was just wondering what those kids were doing before MTN came to Nigeria

Nice Work (#6) by Kole Adeleye, MTN Nigeria     Date: May 6, 2006 12:12 PM

Hi, I have gone through some of your publications and I must commend your ingenuity. Your publication has provided an insight of how importance GIS is to the GSM industry. Keep us informed always. Cheers