Cellular specialized mobile radio service

• US 6,466,766 B1
• Filed: 05/14/1997
• Issued: 10/15/2002
• Est. Priority Date: 07/05/1995
• Status: Expired due to Fees

• Current Assignee: James E. Treatch
• Original Assignee: James E. Treatch
• Inventors: Treatch, James E.
• Primary Examiner(s): Nguyen, Lee
• Application Number:
  US08/856,202
• Time in Patent Office: 1,980 Days
• Field of Search: 455/20, 455/9, 455/15, 455/16, 455/17, 455/32.1, 455/422, 455/562, 455/446, 455/450, 455/524, 455/164.1, 455/164.2, 455/165.1, 455/443, 455/77, 455/76, 455/11.1, 455/22, 455/13.3, 342/457, 342/372, 342/428, 342/433
• US Class Current: 455/20
• CPC Class Codes: H04B 7/1555 Selecting relay station antenna mode, e.g. selecting omnidirectional -, directional beams, selecting polarizations
• CPC Class Codes: H04B 7/2621 using frequency division multiple access [FDMA] H04B7/2615 takes precedence
• CPC Class Codes: H04W 16/24 Cell structures

Abstract

An SMR repeater is made agile by adding a microprocessor controlled frequency selection circuit to enable the repeater to operate on any one of several available frequencies in a band. For dispatch service, the output of the repeater is switched to a power amplifier feeding an omni-directional antenna. The repeater scans several frequencies sequentially. If a signal is detected, scanning is halted to provide repeater service, after which scanning is resumed. The frequency agile repeater is coupled to an antenna system having a narrow beam which can be steered electronically. A control computer scans the azimuth of the beam. The computer divides a service area into a plurality of cells extending radially from the antenna system and assigns channels as needed to service a subscriber. More than one cell can be on the same frequency without interference. The microprocessor includes a table in memory of call signs corresponding to particular transmission frequencies and causes the repeater to transmit the appropriate call sign when transmitting at a particular frequency.

Claims

1. A specialized mobile radio system for providing both dispatch and cellular radio operations in a predetermined propagation area, said system comprising:

an antenna system having an electronically steerable, narrow beam;

at least one repeater coupled to said antenna system, said repeater operable in any one of a plurality of frequencies and capable of changing from one frequency to another frequency in a predetermined sequence;

a control computer coupled to said repeater and to said antenna for rotating the beam of said antenna and for scanning a plurality of frequencies to provide service in a plurality of cells extending radially from said antenna system;

wherein said control computer includes a memory containing a table of call signs corresponding to said plurality of frequencies and said computer causes each repeater to automatically identify itself with one of said call signs when the corresponding frequency is selected for transmission by downloading frequency and call sign data to each repeater.

2. A mobile radio system for operation in a predetermined propagation area, said system comprising:

at least two frequency agile repeaters in said propagation area, wherein a first of said repeaters scans all channels for activity in said area;

a computer coupled to said repeaters for controlling the frequencies thereof;

said computer including memory, wherein a table of available frequencies for transmission and for reception is stored in said memory and said computer causes said repeaters to operate on preselected frequencies under software control; and

an omnidirectional antenna coupled to said first repeater and a steerable antenna array coupled to a second repeater.

3. The mobile radio system as set forth in claim 2 wherein said first repeater detects a transmission and transfers frequency data to said second repeater for re-sending said transmission and continued communication.

4. The mobile radio system as set forth in claim 2 wherein said memory contains a table of call signs, wherein a call sign is associated with a particular transmission frequency;

and

wherein said computer causes each repeater to transmit the call sign associated with transmission frequency then in use by the repeater by downloading frequency and call sign data to each repeater.