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Missed Call Notification

Service Algorithms "Missed Call Notification"

For using the service “Call forwarding – Not Reachable” the “Missed Call Notification” server has to be set. Forwarding can be set by the subscriber (from the mobile terminal), or be the MSC personnel (as the default forwarding service). The call to the unavailable subscriber is forwarded to the system that extracts the numbers of the calling and the initially called parties.

There are three main algorithms:

  • the system plays back a predefined voice message to the calling party and disconnects;
  • the system releases the call with predefined release cause to use MSC voice announcement system;
  • the system supports CAMEL and uses appropriate algorithms.

The system stores the number of the calling party, date, and time of the call and adds them to the message to be sent to the calling party (if this is the first call for this subscriber, then the system forms new message, otherwise this record will be added to the previously composed message). Then the composed/modified message is sent to the SMS center via SMPP. Messages are sent using the SMS center’s message replacement mechanism via replace_sm SMPP message to avoid overflowing the memory of the cell phone with numerous messages when the subscriber becomes available. Such approach dramatically increases the convenience of using the service.

In case of the information exceeds the size of one message, the system can send concatenated messages or a message sequence.

"Notify Me"

Another service provided by the Missed Called Notification System is the notification of the reappearance of the previously unavailable subscriber on the network.

This service can be provided as an additional feature of the “Missed Call Notification” service or as a standalone service. Once the message with the list of missed calls reaches the called party, the system will send a “Notify Me” message for the calling party to SMSC.

Subscriber Profiles and Policy Management

The system supports flexible profile and policy management.

"White lists" of called and calling parties for the "Missed Call Notification" and "Notify Me" services are supported. These are lists of numbers and prefixes defined using regular expressions.

The "white lists" of called/calling parties determines the ranges of numbers and/or separate numbers of subscribers authorized to receive messages from the "Missed Call Notification"/"Notify Me" service respectively.

Individual subscriber profiles are supported. An individual profile has the following parameters:

  • Subscription to the "Missed Call Notification" service;
  • Subscription to the "Notify Me" service;
  • Message profile (header, footer, language and template of the message).

«Notify Me» subscription parameter is used to disable the notification of the calling party about the reappearance of the subscriber’s terminal on the network.

Also subscriber can define personal white list for Notify Me service. Only subscribers included in white list will receive Notify Me messages. Such approach allows to save user privacy. This list can be modified via SMS, USSD or from Customer Care WEB-site.

Subscriber profiles can be managed either by the System Administrator, or by subscribers themselves by means of special SMS or USSD requests processed by the special ESME connected to the SMSC.

Message Format

The message format is specified by the System Administrator.

Message text example with calls grouped by caller number:
"You have missed calls: [N calls from #…, last call at mm:hh, MMDD/YYYY], [N calls from #…, last call at mm:hh, MM/DD/YYYY], …, [N calls from #…, last call at mm:hh, MM/DD/YYYY]."

Event and Alarm Logging

The Protei missed called notification system (“Missed Call Notification”) has flexible event logging and statistics collection subsystems that allow collection of all information that is necessary for system functioning analysis and business-parameters analysis. The following information is available from event logging subsystem:

  • Incoming calls log and counters;
  • SMS sending log and counters;
  • SMS delivery log and counters;
  • Profile change log and counters;
  • Alarm log (SNMP optionally available).

Administration and Management

  • SS7 Settings management;
  • Service parameters management;
  • Subscriber profile management;
  • Message management;
  • SMPP connection parameters management;
  • Statistic and CDR information viewing.

Communication with the telecom equipment

  • MSC interface: E1s, SS7;
  • SMSC interface: SMPP v3.4 over TCP/IP.

System architecture, capacity, and principles of scaling

The Protei missed called notification system (“Missed Call Notification”) is a carrier-class system that can be scaled horizontally. Automatic configuration synchronization between modules is supported. Network based architecture additionally increases system reliability. The modules are used in the load-sharing mode. If one of the modules fails, the traffic is redistributed among other modules without any service interruption.

Capacity of one module is 4E1 (when using Service Node scheme), up to 8 signaling links, up to 500 TPS (transaction per second).