UPDATING TECHNIQUE FOR
DOWNLOADING NEW SYSTEM
IDENTIFICATION (SID) LIST INTO A
 Inventors: Richard Lynch. Yardley. Pa.; Robert T. Braun. Pittstown; Michael Haberman. Morris Plains, both of N.J.
 Assignee: Bell Atlantic Mobile Systems, Inc.,
 Appl. No.: 36236
 Filed: Dec. 22,1994
 Int CI.6 H04Q 7/20; H04Q 7/38
 U.S. CI 455/419; 455/432; 455/435;
455/436; 455/517; 455/552
 Field of Search 379/58. 59, 60,
379/61, 62; 455/33.1, 33.2. 54.1, 54.2. 406, 418. 419. 422, 424. 425, 432. 435, 436, 552, 560, 517, 515
 References Cited
U.S. PATENT DOCUMENTS
A cellular telephone system is upgraded by modifying subscriber units for selective service provider acquisition during roaming. Priority of acquisition is given to those service providers associated with the home service provider. These preferred service providers are identified by System Identification (SIDs) numbers. A roaming subscriber unit will tune to control frequencies to identify all of the system providers operating in a physical area to which the subscriber has roamed. The SIDs of those system providers available are compared to a preferred SJD list contained within the subscriber unit. Selection is made based upon a priority of those system providers having arrangements with the home system provider. The SID lists in the subscriber units are modified based upon a version number for each update on the SID list.
34 Claims, 7 Drawing Sheets