Registration

An application can be registered in a variety of ways; the method used depends on the application type and user preferences. The registration can be manual, automatic, polled, or based on some user-specified profile:

• Manual registration requires the mobile user to perform some task to indicate that he is likely to be accessible through an application. He might enter his username and password into a secure web page or dial a particular phone number and enter a personal code. The user might provide an estimate of how long he expects to use the application, or might perform another manual task to deregister the application.

• Automatic registration relieves the user from any manual task; instead, the application or operating system senses a user's presence and automatically registers with the Tracking Agent. For example, a device might assume that a user is present when he turns on the device, or when it detects that the user's ``smart badge'' is within range. This is just a hint that the user is present; it is the responsibility of automatic registration mechanisms to maximize the probability that this information is accurate while still being user-friendly. This automatic type of registration requires new software on the device.

• Polled registration requires no effort from either the user or the application. The Tracking Agent periodically polls each of a user's applications or devices to detect if the application is running or the device is turned on. For example, polling might be done by pinging the device or by sending a message to the application and waiting for an acknowledgement. Polled registration is not practical for certain devices, such as one-way pagers.

• User-specified profiles allow users to specify a priori which applications they are likely to be using in the future. A user might have a profile that indicates the days and times he is likely to use each application. The user can modify the profile as often as desired. Although this option does not provide dynamic detection of active applications, as the previous methods do, it is simple to implement and may be the only feasible option for receive-only devices like one-way pagers.