3G UMTS Call Setup Success Rate (CSSR) Calculator

In a 3G UMTS (Universal Mobile Telecommunications System) network, the Call Setup Success Rate (CSSR) is a key performance indicator (KPI) that measures the network’s ability to successfully establish voice calls.

Definition

CSSR represents the percentage of call attempts that successfully transition from initiation to connection within a specified time frame. It is an important metric for assessing network reliability, particularly for voice services, and indicates how often users can initiate calls without issues.

Call Setup Success Rate Calculator

Here’s how to calculate CSSR:

EXAMPLE:

• Number of successful call attempts = 950
• Total number of call attempts = 1000

CSSR (Output) = 95

Call Setup Success Rate (CSSR) Formula

Following is the formula to calculate CSSR:

CSSR = (Number_of_successful_call_setups / Total_number_of_call_attempts) x 100

Factors Affecting CSSR

Several factors can impact CSSR, including the following:

• Signal Quality and Coverage: Poor signal strength or high interference can result in call setup failures.
• Congestion: High network load can lead to call setup failures due to resource unavailability.
• Core Network Performance: Failures in the core network, such as issues in call routing or switching, can also reduce CSSR.
• Radio Link Failures: Failures in establishing a stable radio link between the user device and the base station can affect call success.

Target CSSR in UMTS

The target CSSR in a well-optimized UMTS network is typically above 95%, ensuring that most call attempts are successful, providing a reliable experience for users. Maintaining a high CSSR is essential for customer satisfaction, as it directly impacts users’ ability to make calls without interruptions or setup failures.