Multi-frequency wireless communication device

DETAILED DESCRIPTION OF PREFERRED EXEMPLARY EMBODIMENTS OF THE INVENTION FIG.
1 schematically depicts a typical cellular communication system 10.
In this case, the system 10 is depicted to include three subscriber units 12 (which may be portable cell-phones, PPCD's, or PC's equipped to communicate over the cellular communication system depicted, for example), and three base stations 14.
However, it will be understood that the system 10 is merely exemplary and for purposes of illustrating by example the principles of the invention, and is not to be misconstrued as implying a limitation on the invention.
A real cellular communication system may include a large number of base stations, and a great number of subscriber units which are accessing or participating in the system at any one time.
An alternative configuration of the invention may take the form of a private wireless communication system, such as would be used within the considerable confines of a large office building complex or manufacturing facility.
The schematic representation of such a private wireless communication system would appear much the same as FIG.
1.
Again, the subscriber units 12 can include mobile units such as hand-held portable telephones (i.
e.
, the now-familiar cellular telephones), stationary units (such as desk top computers), and portable personal communication devices (PPCD's--such as palm-top computers equipped with radio-frequency modems and/or radio frequency facsimile devices).
The system 10 also includes a number of base stations 14 that allow the subscriber units 12 to communicate with each other and with other communication devices in other networks.
As is well understood by those ordinarily skilled in the cellular communication art, the system 10 covers a geographic area that is effectively divided into a grid or array of cell sites, with each cell site containing at least one base station 14.
Each base station 14 communicates with all subscriber units 12 within the area of its respective cell site via radio frequency ("RF") signals