Telecommunications – Radiotelephone system – Zoned or cellular telephone system
Reexamination Certificate
2005-03-30
2010-11-23
Afshar, Kamran (Department: 2617)
Telecommunications
Radiotelephone system
Zoned or cellular telephone system
C455S456100, C455S525000, C455S440000, C370S331000
Reexamination Certificate
active
07840227
ABSTRACT:
Mobile devices (121, 122, . . . , 12n) are handed off in overlapping cells (181, 182, . . . , 18n) by tracking a velocity (speed and direction) of movement of any number of the mobile devices (121, 122, . . . , 12n). Access points (141, 142, . . . , 14n) are each located in an associated operational cell (181, 182, . . . , 18n) and each operates at a dedicated frequency. The initial signal strengths are measured in advance at predefined locations within a defined space (16) to define signal strengths as location map (42). A nearby initial access point (typically the nearest) and at least two nearby (typically next nearest) access points are assigned for one of the mobile devices (121, 122, . . . , 12n), and the frequencies of each access point identified. A tracking processor (50) periodically scans the frequencies of the nearby access points to determine the location velocity of the mobile device and predict when a handoff will be appropriate. E.g., the actual signal strength measurements between the mobile device and the nearby access points are collected and analyzed to determine a proper time for a handoff of one or more of the nearby access points.
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Baumeister Markus
Kahlert Joachim J.
Wischhusen Olaf
Afshar Kamran
Koninklijke Philips Electronics , N.V.
Ngo Chuong A
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