Fast channel access protocol for a two-way communication system

• US 5,450,611 A
• Filed: 08/23/1991
• Issued: 09/12/1995
• Est. Priority Date: 03/29/1988
• Status: Expired due to Term

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Sasuta, Michael D., Gustafson, Leslie G. Jr., Bonvallet, Michael J., Grube, Gary W.
• Primary Examiner(s): Urban, Edward F.
• Application Number:
  US07/753,016
• Time in Patent Office: 1,481 Days
• Field of Search: 455/34.1, 455/34.2, 455/35.1, 455/9, 455/11.1, 455/20, 455/54.1, 455/54.2, 455/56.1, 455/67.3, 455/102, 379/58, 379/63
• US Class Current: 455/509
• CPC Class Codes: H04W 84/08 Trunked mobile radio systems

Abstract

Requesting (transmitting) subscriber units may immediately begin transmitting an information signal over an assigned communication channel. Receiving subscriber units immediately unmute their speakers and monitor the assigned communication channel and attempt to detect a code, which indicates that they are monitoring the correct communication channel. At the central station (repeater), the information signal may be immediately repeated, unless an interference signal is present. In this way, the information signal may be rapidly disseminated (repeated) to improve subscriber access time, while providing assurance that the receiving subscribers will not receive a noise signal or the interference signal.

Claims

1. In a two-way communication system having a central unit for allocating a limited number of communication channels among a plurality of subscriber units, a communication method comprising the steps of:

at least some of the plurality of subscriber units;

(a) receiving a channel grant code;

(b) unmuting and monitoring, substantially immediately, a channel identified by said channel grant code;

(c) determining whether a transmit information signal has been received on said channel identified by said channel grant code within a time interval; and

(d) continuing to remain unmuted and monitor said channel identified by said channel grant code if said transmit information signal has been received within said time interval;

which communication method includes the central unit steps of;

(e) transmitting said channel grant code;

(f) transmitting, automatically, at least said transmit information signal upon said channel identified by said channel grant code;

(g) determining whether an interference signal is present upon said channel identified by said channel grant code;

(h) muting the transmit information signal to the at least some of the subscriber units when an interference signal has been detected prior to detecting a connect signal from the at least some of the subscriber units;

(i) receiving a message comprising at least an information signal and the connect signal from said channel identified by said channel grant code;

(j) repeating at least a portion of said transmit information signal during a second time interval if said interference signal is not present; and

(k) continuing to repeat said at least a portion of said transmit information signal if said connect signal is detected within said second time interval.

2. In a two-way communication system having a central unit for allocating a limited number of communication channels among a plurality of subscriber units, a communication method comprising the steps of:

at least some of the plurality of subscriber units;

(a) receiving a channel grant code;

(b) transmitting, substantially immediately, an information signal upon a channel identified by said channel grant code;

(c) unmuting and monitoring, said channel identified by said channel grant code after transmitting;

(d) determining whether a transmit information signal has been received from said channel identified by said channel grant code within a time interval; and

(e) continuing to remain unmuted and monitor said channel identified by said channel grant code if said transmit information signal has been received within said time interval;

which communication method includes the central unit steps of;

(f) transmitting said channel grant code;

(g) transmitting, automatically, at least said transmit information signal upon said channel identified by said channel grant code;

(h) determining whether an interference signal is present upon said channel identified by said channel grant code;

(i) muting the transmit information signal to the at least some of the subscriber units when an interference signal has been detected prior to detecting a connect signal from the at least some of the subscriber units;

(j) receiving a message comprising at least said information signal and the connect signal from said channel identified by said channel grant code;

(k) repeating at least a portion of said transmit information signal during a second time interval if said interference signal is not present; and

(l) continuing to repeat said at least a portion of said transmit information signal if said connect signal is detected within said second time interval.

3. In a two-way communication system having a central unit for allocating a limited number of communication channels among a plurality of subscriber units, a communication method comprising the steps of:

(a) transmitting a channel grant code to a particular subscriber unit;

(b) transmitting, automatically, a transmit information signal upon a channel identified by said channel grant code;

(c) determining whether an interference signal is present upon said channel identified by said channel grant code;

p1 (d) muting the transmit information signal to the subscriber unit when an interference signal has been detected prior to detecting a connect signal from the subscriber unit; and

(e) receiving a message comprising at least an information signal and the connect signal from said channel identified by said channel grant code and repeating, if said interference is present, at least said transmit information signal only after detecting said connect signal.

4. In a two-way communication system having a central unit for allocating a limited number of communication channels among a plurality of subscriber units, a communication method comprising the steps of:

at the central unit;

(a) transmitting a channel grant code to a particular subscriber unit;

(b) transmitting, automatically, a transmit information signal upon a channel identified by said channel grant code;

(c) determining whether an interference signal is present upon said channel identified by said channel grant code;

(d) muting the transmit information signal to the subscriber unit when an interference signal has been detected prior to detecting a connect signal from the subscriber unit;

(e) receiving a message comprising at least an information signal and the connect signal from said channel identified by said channel grant code;

(f) repeating at least said transmit information signal for a time interval if said interference signal is not present; and

(g) continuing to repeat at least said transmit information signal if said connect signal is detected within said time interval.

5. In a two-way communication system having a central unit for allocating a limited number of communication channels among a plurality of subscriber units, a communication method comprising the steps of:

at least some of the plurality of subscriber units;

(a) receiving a channel grant code;

(b) transmitting, substantially immediately, an information signal upon a channel identified by said channel grant code;

(c) unmuting and monitoring, said channel identified by said channel grant code after transmitting;

(d) determining whether a subaudible signal has been received from said channel identified by said channel grant code within a time interval; and

(e) continuing to remain unmuted and monitor said channel identified by said channel grant code if said subaudible signal has been received within said time interval;

which communication method includes the central unit steps of;

(f) transmitting said channel grant code;

(g) transmitting, automatically, a transmit information signal upon said channel identified by said channel grant code;

(h) determining whether an interference signal is present upon said channel identified by said channel grant code;

(i) muting the transmit information signal to the at least some of the subscriber units when an interference signal has been detected prior to detecting a connect signal from the at least some of the subscriber units;

(j) receiving a message comprising at least said information signal and the connect signal from said channel identified by said channel grant code;

(k) repeating, if said interference is not present, at least a portion of said transmit information signal during a second time interval; and

(l) continuing to repeat said at least a portion of said transmit information signal if said connect signal is detected within said second time interval.

6. In a two-way communication system having a central unit for allocating a limited number of communication channels among a plurality of subscriber units, a communication method comprising the steps of:

(a) transmitting a channel grant code to a particular subscriber unit;

(b) transmitting, automatically, a subaudible signal upon a channel identified by said channel grant code;

(c) determining whether an interference signal is present upon said channel identified by said channel grant code;

(d) muting the transmit information signal to the subscriber unit when an interference signal has been detected prior to detecting a connect signal from the subscriber unit; and

(e) receiving a message comprising at least an information signal and the connect signal from said channel identified by said channel grant code and repeating, if said interference signal is present, at least said transmit information signal only after detecting said connect signal.