True Million of Operations per Second

Description

True Million of Operations per Second (TMOPS) is a specific, standardized benchmark defined in 3GPP TS 46.055. It is designed to measure and express the call processing capacity of a GSM Base Station Controller (BSC). The BSC is a critical network element responsible for radio resource management, handover control, and call setup/teardown for multiple Base Transceiver Stations (BTSs). The TMOPS value represents the maximum sustainable rate at which the BSC can execute a defined set of 'operations' that model real-world GSM call processing tasks.

The benchmark operates by subjecting the BSC under test to a simulated traffic load generated by a test system. This load is defined by a specific traffic model that includes a mix of operation types, such as mobile-originated call setup, mobile-terminated call setup, intra-BSC handover, inter-BSC handover, location updating, and Short Message Service (SMS) submission. Each of these real-world procedures is broken down into a countable number of standardized 'TMOPS operations.' The test increases the offered load until the BSC reaches its maximum capacity, defined as the point where it maintains a specified Grade of Service (GoS), typically a call setup success rate and delay threshold. The resulting maximum load, measured in millions of these operations per second, is the TMOPS rating.

Architecturally, the measurement focuses on the BSC's central processing unit (CPU) and software efficiency in handling the control plane signaling (through the A and Abis interfaces) and managing associated databases (like the visitor location register functions). It does not measure user data throughput. The TMOPS metric is crucial for network planners, as it allows them to dimension the number of BSCs needed for a target subscriber population and traffic profile, and to compare the capacity of different vendors' BSC equipment on a like-for-like basis using a common, rigorous benchmark.

Purpose & Motivation

TMOPS was created to address the problem of ambiguous and non-comparable vendor claims regarding the capacity and performance of GSM Base Station Controllers. Prior to its standardization, vendors used proprietary metrics or high-level statements about the number of supported subscribers or call attempts, which made accurate network planning and fair equipment procurement comparisons difficult. Different internal architectures and software efficiencies meant that raw hardware specifications (like CPU clock speed) were poor indicators of real-world call handling capability.

The introduction of TMOPS in 3GPP Release 8 provided a standardized, reproducible, and objective benchmark. It solved this by defining a precise traffic model and a countable set of operations that accurately reflect the computational burden of GSM call processing. This allowed operators to specify required TMOPS ratings in their equipment tenders, ensuring selected BSCs could handle the projected busy-hour traffic. It also motivated vendors to optimize their BSC software efficiency to achieve higher TMOPS ratings on given hardware, ultimately leading to more cost-effective and capacity-dense network infrastructure. The metric remains relevant for GSM network expansion and modernization.

Key Features

• Standardized benchmark defined in 3GPP TS 46.055 for GSM BSC capacity measurement
• Quantifies capacity as millions of defined call processing operations per second
• Uses a specific traffic model mixing call setups, handovers, location updates, and SMS
• Defines a precise Grade of Service (GoS) threshold to determine maximum sustainable load
• Provides an objective basis for comparing capacity of different vendors' BSC equipment
• Essential for accurate network dimensioning and capacity planning in GSM networks

Evolution Across Releases

Defining Specifications