US 4,545,071 AGranted

Portable radio for a zoned data communications system communicating message signals between portable radios and a host computer

AssigneeMotorola, Inc.

InventorThomas A. Freeburg

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Abstract

A data communications system is described that covers a geographic area divided into a plurality of non-overlapping zones and includes a general communications controller (GCC), a plurality of channel communications modules (CCM) and associated transmitters and receivers, and a plurality of portable radios. Message signals carrying alphanumeric information are communicated between the GCC and the portable radios by way of a radio channel. Each CCM takes a signal strength measurement every time it receives a message signal from a portable radio. The GCC gathers the signal strength measurements from the CCM receivers receiving the same message signal and computes an adjusted signal strength for each zone. The GCC then selects the zone having the largest adjusted signal strength for determining the location of the portable radio that transmitted the message signal. Whenever the GCC transmits a message signal to a portable radio, the CCM transmitter is used that covers the zone having the largest adjusted signal strength for the last transmission from that portable radio. Since the GCC can be simultaneously transmitting message signals to portable radios in other zones using non-interfering CCM transmitters, information throughput is greatly enhanced.

Claims2

Dependent claims

A data radio for communicating via a radio channel message signals to a host computer of a data communications system coupled to a plurality of radio receivers covering a geographical area divided into zones, said message signals including coded data packets having a binary preamble, a synchronization word and an information word containing an identification code and a command, status or data word, said radio comprising:

transmitting means coupled to one of two antennas for transmitting on the radio channel message signals applied thereto;
receiving means coupled to the two antennas for receiving message signals from the radio channel;
keyboard means for entering message signals;
display means for displaying data;
at least first, second and third register means for storing an identification code uniquely identifying said data radio, a first data word and a second data word, respectively;
and
processing means coupled to the transmitting means, receiving means, keyboard means, display means and first, second and third register means for receiving and transmitting message signals, applying to the transmitting means message signals having information words including a data word from the second or third register means, and receiving from the receiving means information words of received message signals and storing the command, status or data word thereof in the second or third register means when the received identification code is the same as the identification code stored in the first register means.

4 more elements

Dependencies are inferred from the claim text.