Method and apparatus for controlling a TDM communication device

• US 4,742,514 A
• Filed: 03/25/1986
• Issued: 05/03/1988
• Est. Priority Date: 03/25/1986
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Baker, James C., Goode, Steven H., Kazecki, Henry L.
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Marcelo, Melvin
• Application Number:
  US06/843,961
• Time in Patent Office: 770 Days
• Field of Search: 370/85, 370/94, 370/95, 370/100, 370/97, 370/50, 370/84, 370/26, 370/29, 370/109, 375/3, 379/88, 379/59, 379/63, 381/36, 455/53, 455/54, 455/17
• US Class Current: 370/280
• CPC Class Codes: H04B 1/66 for reducing bandwidth of signals; for improving efficiency of transmission H04B1/68 takes precedence

Abstract

A time division multiplexed (TDM) communication device controller is disclosed, which controls all signalling, synchronization and supervisory functions. In one embodiment, the invention operates to control a remote communication device having a vo-coder and buffering means. The remote communication device is enabled to operate as a dispatch, full duplex or a combination dispatch/full duplex communication device. In another embodiment, a primary station (repeater) is controlled to operate as a single frequency repeater (SFR) or as a multi-frequency TDM repeater.

Claims

1. A method for controlling a remote communication device to transmit voice or data signals preambled by a data signal in a time division multiplex communication system having at least one primary station and a plurality of remote units, comprising the steps of:

(a) transmitting an activation code to the primary station if the primary station is determined to be inactive;

(b) synchronizing to a signal received from the primary station;

(c) enabling a vo-coding analyzer to vo-code a voice signal at a selected coding rate, V, to provide an information signal;

(d) buffering said information signal to provide a buffered signal;

(e) transmitting said buffered signal preambled by a data signal over a communication channel having a predetermined maximum data rate, C, in accordance with a time division multiplex protocol defining N time slots, where N is a positive integer less than or equal to C/V, where V comprises said selected coding rate, said buffered signal preambled by said data signal being transmitted in at least one of said N time slots at a rate exceeding 2 V.

2. The method of claim 1, wherein the step of synchronizing comprises the steps of:

(a) adjusting a bit synchronization means in response to a bit sync signal;

(b) detecting a predetermined frame synchronization word.

3. The method of claim 2, wherein said detecting step comprises detecting said predetermined frame synchronization word based on a three of five majority decision.

4. The method of claim 1, wherein said enabling step enables a data source to provide said information signal.

5. A method for controlling a remote communication device to receive an information signal including at least data or vo-coded voice signals preambled by a data signal, said remote unit operating in a time division multiplex communication system having at least one primary station and a plurality of remote units, said method comprising the steps of:

(a) synchronizing to a signal received from the primary station;

(b) receiving the information signal during at least one time slot from a communication channel having a predetermined maximum data rate, C, in accordance with a time division multiplex protocol defining N time slots, where N is a positive integer less than or equal to C/V, where V comprises a selected coding rate, said information signal being received at a rate exceeding 2 V to provide a received information signal;

(c) buffering said received information signal to provide a buffered signal;

(d) synthesizing a recovered voice signal from said buffered signal at said selected coding rate.

6. The method of claim 5, which includes the step of unmuting the remote device in response to receiving the information signal.

7. The method of claim 5, wherein the step of synchronizing comprises the steps of:

(a) adjusting a bit synchronization means in response to a bit sync signal;

(b) detecting a predetermined frame synchronization word.

8. The method of claim 7, wherein said detecting step comprises detecting said predetermined frame synchronization word based on a three of five majority decision.

9. The method of claim 5, which includes the step of updating a memory location to contain time slot assignment information received from the primary station.

10. The method of claim 5, wherein said synthesizing step includes the step of enabling a vo-coding synthesizer.

11. A method for controlling a primary station to operate in a time division multiplex communication system having a plurality of remote units, comprising the steps of:

(a) receiving an activation code from at least one of the plurality of remote units;

(b) transmitting a data signal containing at least a synchronization portion and slot assignment information to at least one remote station;

(c) receiving an information signal from a remote unit, including a preambled data signal, during at least one time slot from a communication channel having a predetermined maximum data rate, C, in accordance with a time division multiplex protocol defining N time slots, where N is a positive integer less than or equal to C/V, where V comprises a selected coding rate, said information signal being received at a rate exceeding 2 V to provide a received information signal;

(d) repeating said received information signal preambled by a data signal in at least one of said N time slots at said rate exceeding 2 V;

(e) operating, thereafter, continuously until it is determined that none of the plurality of remote units have transmitted information for a time interval, after which, the primary station automatically deactivates.

12. The method of claim 11, which includes the step of re-transmitting said data signal of step (b) upon the failure of receiving the preambled data signal of step (c).

13. The method of claim 11, which includes the step of buffering said received information signal of step (c) prior to repeating same in step (d).

14. A method for communicating information between a first time division multiplex communication device and a plurality of remote time division multiplex communication devices via a time division multiplex repeater, comprising the steps of:

(a) at a first communication device;

(1) transmitting an activation code to the repeater if the repeater is determined to be inactive;

(2) transmitting an information signal to the repeater in a first time slot over a communication channel having a predetermined maximum data rate, C, in accordance with a time division multiplex protocol defining N time slots, where N is a positive integer less than or equal to C/V, where V comprises a selected coding rate, said information signal being transmitted at a rate exceeding 2 V;

(b) at the repeater;

(1) receiving said activation code;

(2) transmitting a synchronization signal to the plurality of remote communication devices;

(3) receiving said information signal from said communication channel during said first time slot;

(4) repeating said information signal in a second time slot preambled by a data signal;

(5) operating, thereafter, continuously until it is determined that none of the plurality of remote units have transmitted information for a time interval, after which, the repeater automatically deactivates.

(c) at the remaining plurality of remote communication devices or a portion thereof;

(1) synchronizing to said synchronization signal;

(2) receiving said repeated information signal in an assigned time slot.

15. The method of claim 14, wherein the step of synchronizing at said remote communication devices comprises the steps of:

(a) adjusting a bit synchronization means in response to a bit sync signal;

(b) detecting a predetermined frame synchronization word.