OVERVIEW COMPANY Mobile Systems, Inc. United Kingdom BUSINESS EXPERTISE Providing products and services for cellular network engineers APPLICATIONS Network Planning Tool (NPT) and Databuild PLATFORMS Sun, Hewlett-Packard BUSINESS CHALLENGE Managing large numbers of interconnected nodes using complex algorithms VERSANT SOLUTION Provided an integrated network planning and management environment for cellular operators

The MSI product set currently consists of the flagship product, PlanNet, the Network Planning Tool (NPT), and Databuild, each focused on a different task faced by cellular network engineers. PlanNet is the core product used by MSI itself to help size and locate network elements, NPT solves the problem of where to place cells, while Databuild allows network operators within the Operations Management Center (OMC) to set and tune these cells in the field. The technical challenge couples a standard network management hurdle - managing large numbers of interconnected nodes - with the need to solve complex algorithms related to the physics of radio transmission.

"We need to provide at least a crude guess of where to place cells based on the expected growth over the next 10 years," said Andrew Schneider, leader of the NPT project at MSI. "Network planners will continue to locate cells themselves, but our tools provide a distinct advantage over the spreadsheets currently in use." For example, NPT specifically allows planners to estimate the amount of future traffic and project the level of fixed network equipment requires.

While PlanNet represents the central tool for MSI, the company recognized the need to move beyond their flat-file origins and move into the world of databases. The sophisticated algorithms, placement rules, network complexity, and flux over time created a problem ideal for objects. Only with objects could MSI handle the overall system complexity and productize the solution.

WHY USE AN ODBMS

With objects as the development paradigm, the team considered the issue of a database and recognized early on that standard databases would not be effective for this problem.

Performance was a key criteria for a tool that allowed engineers to test out assumptions and play out "what if." The NPT application constantly traverses large networks of objects," said Schneider. "It was obvious to us that a relational database could not work." With the technical team pointing the way, MSI's management approved using an ODBMS.

Besides the desire to have a single database platform, the Databuild product has its own requirements. The performance characteristics of a mobile phone network are highly dependent on the correct configuration of thousands of radio parameters at the cell sites that make up the network. Moreover, many of the parameters are interdependent so achieving a consistent configuration over time is very difficult. Keeping up with the complexity of the network and with its inevitable evolution raised data management issues beyond those solved by RDBMS's. Versioning and configuration management become critical where engineers need to manage different versions of BSS parameters for each cell. Only then can operators experiment with changes and merge data between configurations.

Schneider concluded, "We knew that we were taking a chance in choosing a relatively new technology, but the problem space would not allow us an alternative." So in early 1994, the team began evaluating object databases.

WHY VERSANT?

In order to judge the merits of products from Versant, Objectivity and Object Design, MSI drew up a list of ideal features. Beyond standard database features like performance, reliability, and high availability, the team highlighted the following issues: the ability to store objects and their methods, object-level locking to ensure high concurrency, and versioning.

In the end, the decision between Versant and ObjectStore came down to MSI's fundamental belief that Versant provided a more complete object management system; ObjectStore was perceived to provide persistent storage. To MSI, this meant providing the reliability and scalability expected from databases, not simply acting as "extended virtual memory."

Because Versant implements an object manager, the database shields developers from many core issues involving distribution and concurrency. Over time, MSI was convinced that Versant would be a better and more efficient development choice.

"Both products were fast," said Martin Larsson, product manager at MSI, "but the real consideration was to choose the product that was going to allow MSI to do what our products have to do in the future. We could not compromise." MSI chose Versant because of their belief that Versant provided a formal approach to managing objects, including robust transactions and guaranteed data integrity.

THE PROJECT

The team began the project using the CenterLine compiler to ensure cross-platform compatibility between their core Sun and HP platforms. The team also used the Sniff browsing tools. Once the projects were underway, development with Versant was straightforward.

The complexity of the Databuild product stems partially from the requirement that it manage cells from a variety of manufacturers within the same network. As mentioned above, the tool allows operators to store multiple versions of BSS data to explore different configurations and the interaction between cells. All of the configuration data is stored in Versant and the tool allows the tuning of the network elements in the field. Databuild itself represents over 100,000 lines of code.

NPT is an even larger challenge. As described above, the tool must be able to evaluate a variety of scenarios, answer questions about coverage, and display them effectively for a network planner. To solve this problem, the team wrote over 600 classes, of which 150 are persistent.

NEXT STEPS

Databuild is now in use throughout Europe, including EPlus in Germany, CellNet in the UK, and OMNITEL in Italy. NPT is currently in field test with shipment expected in December 1995. The company intends to use Versant as a software backbone for its entire set of tools, including the flagship PlanNet Tool. Doing so will provide an integrated network planning and management environment for cellular operators. With much at stake, having a flexible and effective means of optimizing network investments will provide significant returns to large cellular operators.