Zoned data communications system for communicating message signals between portable radios and a host computer

• US 4,525,861 A
• Filed: 08/13/1984
• Issued: 06/25/1985
• Est. Priority Date: 11/12/1982
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Freeburg, Thomas A.
• Primary Examiner(s): NG, JIN FAY
• Application Number:
  US06/639,770
• Time in Patent Office: 316 Days
• Field of Search: 455/33, 455/52, 455/53, 455/54, 455/56, 455/82, 455/83, 455/137, 179/2 EA, 179/2 EB
• US Class Current: 455/422.1
• CPC Class Codes: H04B 7/0851 using training sequences or error signal minimizing error signal H04B7/0854
• CPC Class Codes: H04W 68/00 User notification, e.g. alerting and paging, for incoming communication, change of service or the like

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.

Claims

1. A data communications system for communicating message signals from a host computer throughout a geographical area divided into zones, comprising:

a communications controller coupled to the host computer for communicating message signals therebetween;

a radio channel for carrying message signals;

a plurality of remote radio stations located anywhere in the geographical area and including a transmitter and antenna for transmitting message signals on the radio channel and a receiver switchably couplable to either the transmitter antenna or another antenna for receiving message signals; and

a plurality of radio channel communications modules each located throughout the geographical area for covering at least one zone and coupled to the communications controller for communicating message signals on the radio channel to the remote radio stations in the zones covered thereby, each radio channel communications module coupled to a transmitter and antenna for transmitting message signals on the radio channel and to a receiver and at least two antennas for receiving message signals from the radio channel.

2. The data communications system according to claim 1, wherein each of said receivers coupled to a corresponding radio channel communications module further includes a maximal-ratio predetection diversity combiner coupled to the two antennas associated with that receiver for combining the signals received by each antenna to provide a composite signal.