Multiple control slot TDM/FDM communication system

• US 4,942,570 A
• Filed: 01/23/1989
• Issued: 07/17/1990
• Est. Priority Date: 01/23/1989
• Status: Expired due to Term

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Kotzin, Michael D., Crisler, Kenneth J., Van den Heuvel, Anthony P., Hong, Daehyoung, Saltzberg, Theodore, Mohl, Lawrence M.
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Edwards, Christopher O.
• Application Number:
  US07/300,392
• Time in Patent Office: 540 Days
• Field of Search: 370/110.1, 370/79, 370/68.1, 370/80, 370/81, 370/84, 379/67, 379/89, 379/68, 379/70
• US Class Current: 370/263
• CPC Class Codes: H04J 3/1647 Subrate or multislot multiplexing
• CPC Class Codes: H04J 4/00 Combined time-division and frequency-division multiplex systems H04J13/00 takes precedence ; data transmission H04L5/26; telemetry G08C15/00

Abstract

A communication system that provides TDM and FDM communications between communication units. At least two control slots are provided in each TDM frame window to provide communication control information such as channel assignment information.

Claims

1. A time division multiplexed communication system for allowing communications between two or more communication units, on a communication channel, wherein said system supports a plurality of TDM frames on said communication channel, and wherein each of said TDM frames includes a plurality of time slots, wherein at least some of said time slots substantially support said communications and at least two of said time slots in each TDM frame on said communication channel each substantially support independent communication control information, such that a communication unit need only receive one of the at least two of said time slots per TDM frame in order to receive communication control information relevant to that communication unit.

2. A time division multiplexed, multiple channel communication system for allowing communications between two or more communication units, wherein said system supports a plurality of TDM frames on at least some of said multiple channels, and wherein each of said TDM frames includes a plurality of time slots, wherein at least some of said time slots substantially support said communications and at least two of said time slots each substantially support independent communication control information, such that a communication unit need only receive one of the at least two of said time slots per TDM frame in order to receive communication control information relevant to that communication unit.

3. The communication system of claim 2 wherein said at least two of said time slots that substantially support communication control information are supported by the same communication channel.

4. The communication system of claim 2 wherein said at least two of said time slots that substantially support communication control information are each supported by different communication channels.

5. The communications system of claim 4 wherein said at least two of said time slots that substantially support communication control information are non-overlapping in time.

6. The communication system of claim 2 wherein said at least two of said time slots that substantially support communication control information are non-adjacent in time.

7. A method of communicating between two or more communication units in a time division multiplexed communication system on a communication channel that supports a plurality of TDM frames, comprising the steps of:

(A) maintaining, in each of said TDM frames on said communication channel, at least three time slots, wherein at least one of said time slots is maintained to substantially support communications between said two or more communication units; and

(B) maintaining at least two of said time slots in each of said TDM frames to each substantially support independent communication control information, such that a communication unit need only receive one of the at least two of said time slots per TDM frame in order to receive communication control information relevant to that communication unit.

8. In a time division multiplexed communication system wherein at least two time slots per TDM frame are system control time slots that are used to substantially support communication control information, a method of assigning, to at least one communication unit, a plurality of time slots, comprising the steps of:

(A) identifying said system control time slots; and

(B) assigning said plurality of time slots to said at least one communication unit such that at least one of said system control time slots does not contend with such assignment.

9. The method of claim 8 wherein communication control information specifically intended for at least said at least one communication unit is transmitted to said at least one communication unit during said system control time slot that does not contend with such assignment.

10. The method of claim 9 wherein said communication control information that is specifically intended for at least said at least one communication unit is transmitted to said at least one communication unit only during said system control time slot that does not contend with such assignment.

11. In a time division multiplexed communication system wherein a plurality of time slots are provided for each TDM frame, and wherein at least some of said time slots can be assigned to facilitate communications between communication units, a method of assigning said time slots comprising the steps of:

(A) monitoring at least one predetermined parameter that is representative, at least in part, of loading for said system;

(B) regulating the number of said time slots in said each TDM frame as commensurate with said monitored parameter; and

(C) assigning said plurality of time slots to at least one of said communication units.

12. The method of claim 11 wherein said predetermined parameter is the average wait time for access to a channel.

13. The method of claim 11 wherein said predetermined parameter is the time of day.

14. A method of substantially simultaneously transmitting and receiving voice information, transmitting or receiving data or a second voice information, and transmitting or receiving communications system control data, in a single subscriber unit, comprising the steps of:

(A) in a first assigned TDM time slot, transmitting said voice information in a TDM format when there is voice information to transmit;

(B) in a second assigned TDM time slot, receiving said voice information in a TDM format when there is voice information to receive;

(C) in a third assigned TDM time slot, one of the following;

(i) transmitting said data in a TDM format when there is data to transmit and receiving said data in a TDM format when there is data to receive;

(ii) transmitting said second voice information in a TDM format when there is voice to transmit and receiving said second voice information in a TDM format when there is voice to receive;

(D) and in a fourth assigned TDM time slot, transmitting communications system control data in a TDM format when there is communications system control data to transmit, and receiving communications system control data in a TDM format when there is communications system control data to receive.

15. The method of claim 14 wherein in said fourth assigned TDM time slot, data is transmitted in a system control data format when there is data to transmit and data is received in a system control data format when there is data to receive.

16. In a time division multiplexed communication system wherein at least one time slot per TDM frame on at least one communication channel is a system control time slot that is used to substantially support communications control information, a method of providing conference communications between at least three communication units, comprising the steps of:

(A) assigning a first communication unit, via said system control time slot, a first time slot for transmitting information and a second time slot for receiving information;

(B) assigning a second communication unit, via said system control time slot, said second time slot for transmitting information and said first time slot for receiving information; and

(C) assigning at least another communication unit, via said system control time slot, said first and second time slots for receiving information;

such that said first and second communication units can conduct a duplex communication, and said another communication unit can receive said duplex communication.

17. In a single subscriber unit, a method of substantially simultaneously transmitting and receiving voice information, receiving another voice message, and receiving communications system control instructions, comprising the steps of:

(A) in a first TDM time slot as assigned pursuant to said communications system control instructions, transmitting a first voice message;

(B) in a second TDM time slot as assigned pursuant to said communications system control instructions, receiving a second voice message, which second voice message is rendered audible;

(C) in a third TDM time slot, receiving said communication system control instructions; and

(D) in a fourth TDM time slot as assigned pursuant to said communications system control instructions, receiving a third voice message, which third voice message is stored in memory and not rendered currently audible.