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Connectivity Is Key to Automated Testing
In order for automated handset testing to work, the device under test must support some mechanism for being stimulated (i.e., having its keys virtually pressed in a way equivalent to a test technician manually pressing keys) and verifying a correct response.

Software-based connectivity mechanisms rely on software agents running on top of or within the operating system to provide test platforms with access to the user interface, internal handset resources, and sufficient capabilities for automating testing of common handset functions. Also software agents can transfer data, including screenshots, back to the test platform over standard device communication interfaces. These screenshots are used to verify proper handset behavior and measure handset performance, such as how long it took for a portal page to appear. With text and screen object recognition technology, a testing platform can even navigate menus dynamically based on context (i.e., find the option marked "Edit") rather than having to know a command's fixed position in a list.

Software agents are invaluable in providing access into handsets. Not only can handset manufacturers, content providers, and carriers test handset functionality, they can also measure the quality of services provided. For example, a testing platform could measure the average time to initiate a call or how quickly a Web page first appears (different from how long until it fully loads).

For multimedia services, testing extends to the perceived quality of images, video, and sound. Just because an image arrived doesn't mean it arrived intact or, as might be the case, that it is the expected image and displayed correctly. Using manual testing processes, human technicians must view the received multimedia data and provide a subjective assessment of its quality, typically using a quality rating scale such as Mean Opinion Score (MOS). Consistency in measurement, however, is difficult to achieve this way.

Automated testing tools now include objective methods for evaluating audio and video. Because of the high data rate associated with the capture of audio and video streams, hardware-based handset connectivity must be employed. Raw audio and video data are captured by the hardware interface and transferred to the testing platform in near real time. Quality assessment is performed in a PC test system where significant computer processing power exists to perform audio and video analysis without negatively impacting performance of the incident test.

Today, software agents can reasonably support the capture of about 4 fps from handsets. However, even with the relatively small amount of frames being captured, the function and behavior of the handset can be adversely impacted. To avoid this problem, hardware-based interfaces must be used. To make multimedia testing common place, handset manufacturers will need to provide hardware-based interfaces from the handset that are capable of passing audio and video data at 30 fps. In this way, a test platform can non-intrusively capture what the user sees on the handset screen and hears from the speaker without impacting the operation of the handset under test.

The Future of Multimedia Testing
It is essential that automated test connectivity become ubiquitous and commonplace. For this to happen, standard testing interfaces are needed. Two examples of existing test interfaces are Mobile Test Connectivity (MTC) from TestQuest and Spirent's Universal Tool Suite (UTS). MTC and UTS provide device stimulation and the screen capture capabilities required to evaluate image quality (see Figure 2).

There is industry pressure from carriers for handset manufacturers to implement interfaces like MTC or UTS in handsets to standardize and simplify handset testing. In at least one case, the carrier tests the interface first and if it fails, rejects the handset without further testing.

Having standard interfaces is an important step in increasing the efficiency of the testing process. Such interfaces create an ecosystem around them of interoperable tools and products that facilitate sharing and collaboration throughout the value chain. MTC and UTS provide a test interface for basic handset functional testing. However, for multimedia testing, standard hardware interfaces are needed. Silicon vendors, handset manufacturers, and carriers need to work together to provide non-intrusive hardware access to data, audio, and video off the handset without involving software agents. Only in this way will it become possible to fully automate not only the functional testing of data and multimedia services but their quality as well.

Many handset manufacturers have already implemented a powerful test interface on their handsets but in most cases these interfaces are not available for use by carriers or application developers. Either the physical connector is removed or the software that supports them is disabled. Understandably, these manufacturers are concerned about the potential problems that could arise by leaving such interfaces exposed to hackers, although these concerns can be addressed by security technologies available today that can protect these interfaces and limit their use to legitimate testing.

In all likelihood, the adoption of a standard testing interface will be driven by the carriers, implemented by the silicon vendors, and supported at the operating system level. Manual testing of data and multimedia services is simply too difficult and costly, not to mention inadequate. A standard test interface that would enable automated testing of every functional aspect of a handset, as well as enable reliable quality testing of multimedia data, would provide tremendous value across the entire value chain, making even greater collaboration possible. Perhaps the most important consideration, however, is that providing a standardized test interface in handsets will yield a significant competitive edge to those handset manufacturers who open them up, because in the end the easier and more cost-effective manufacturers make it for carriers to verify handsets and developers to certify the applications that run on them, the better the chances of their handsets being adopted.

Most carriers recognize that mobile multimedia is still in its early days and they are proceeding with caution. Certainly, being first to market has its advantages but not if services fail to operate reliably. The potential revenues from large-scale deployments of new multimedia and automated workforce services are enticing, but for them to be successful, initial deployments must be flawless.

To ensure reliability, carriers need to be able to verify through comprehensive testing that handsets and services operate as expected over their networks. The complexity of manual testing requires that handset manufacturers, content providers, and carriers utilize automated testing technology to both reduce testing time and cost while increasing test coverage. Each group stands to gain much through automation and standardization of the testing process. By taking advantage of collaboration technologies, valuable test assets can be reused as well as shared across the entire value chain.

Together silicon designers, handset manufacturers, and software developers can work together to reduce overall testing complexity while increasing carrier confidence in a handset's ability to operate in a carrier's network. The end goal is to have carriers adopt handsets into their networks, and there are many ways in which the entire value chain can accelerate and improve the reliability of this process to the benefit of all.

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