CDR (Charging Data Record)

Last updated on Mar 13, 2023

Charging Data Record (CDR) is a critical element in telecommunications billing systems, specifically in the context of mobile networks. CDRs are data records generated by network elements in the mobile network, such as switches, base stations, and routers. CDRs provide information about the usage of various services by the subscribers, including voice calls, SMS, MMS, data usage, and other value-added services.

In simple terms, a CDR is a log of all the services consumed by a subscriber, which contains information such as the time, duration, and type of service used. The CDR data is used by telecom operators for billing, customer care, and network optimization purposes. In this article, we will discuss the structure and usage of CDRs in the telecommunications industry.

Structure of a CDR

A typical CDR consists of various fields that contain information about the service usage of a subscriber. The exact structure of a CDR varies from operator to operator and depends on the technology used in the mobile network. However, there are some common fields that are present in most CDRs, which are discussed below:

Call Detail Record (CDR) Fields

Calling Party Number (CPN): This field contains the phone number of the subscriber who initiated the call or sent the message.
Called Party Number (CDN): This field contains the phone number of the subscriber who received the call or message.
Start Time: This field contains the timestamp when the call or message was initiated.
End Time: This field contains the timestamp when the call or message ended.
Duration: This field contains the duration of the call in seconds.
Call Type: This field specifies the type of call, whether it was a voice call, SMS, MMS, or data usage.
Location: This field contains the location of the subscriber when the call or message was initiated.
Service Provider ID: This field contains the identification number of the telecom operator providing the service.
IMEI Number: This field contains the unique identification number of the mobile device used by the subscriber.

Usage Fields

Volume: This field contains the volume of data used by the subscriber, measured in bytes or kilobytes.
Service Type: This field specifies the type of service used, such as web browsing, email, video streaming, etc.
Usage Time: This field contains the duration of usage of the service, measured in seconds.
Location: This field contains the location of the subscriber when the service was used.

Other Fields

Record ID: This field contains a unique identification number for each CDR.
Sequence Number: This field contains a number that represents the order of the CDR in the sequence of all CDRs generated by the network element.
Call Reference Number (CRN): This field contains a number that identifies the call or message.
Call Status: This field contains information about the status of the call, such as whether it was answered or not.
Subscriber ID: This field contains the identification number of the subscriber.
Tariff ID: This field contains the identification number of the tariff plan used by the subscriber.

Usage of CDRs

CDRs play a critical role in the billing systems of telecom operators. When a subscriber makes a call, sends a message, or uses a data service, a CDR is generated by the network element. The CDR data is collected by the operator's billing system, which processes the data and generates bills for the subscriber. The billing system calculates the charges based on the usage data provided by the CDRs.

In addition to billing, CDRs are also used for customer care purposes. When a subscriber contacts the customer care center with a complaint, the customer care executive can use the CDR data to investigate the issue and resolve it. For example, if a subscriber complains of poor network coverage, the customer care executive can check the CDR data to see if the subscriber was in an area with poor network coverage at the time of the call.

CDRs are also used for network optimization purposes. Telecom operators use the CDR data to analyze the usage patterns of their subscribers and optimize their network infrastructure accordingly. For example, if a particular base station is experiencing high traffic during certain hours of the day, the operator can deploy additional resources to that base station to improve the network quality during those hours.

Challenges with CDRs

While CDRs are a critical component of telecom billing systems, they also pose some challenges. One of the biggest challenges is the sheer volume of CDRs generated by the mobile network. A single base station can generate thousands of CDRs per hour, and a large operator with millions of subscribers can generate millions of CDRs per day. This massive volume of data presents challenges in terms of storage, processing, and analysis.

Another challenge with CDRs is the accuracy of the data. CDRs are generated by network elements in real-time, and sometimes errors can occur during the data collection process. For example, a CDR may be generated for a call that was not actually connected, or the duration of the call may be inaccurate. These inaccuracies can lead to incorrect billing and cause customer dissatisfaction.

Conclusion

In conclusion, Charging Data Records (CDRs) are a critical component of telecom billing systems. CDRs provide information about the usage of various services by the subscribers, including voice calls, SMS, MMS, data usage, and other value-added services. CDRs are used by telecom operators for billing, customer care, and network optimization purposes. However, the massive volume of CDR data generated by mobile networks and the accuracy of the data pose significant challenges. Telecom operators need to invest in the infrastructure and technology required to manage and analyze this data to improve the accuracy of billing and provide better customer service.