TDMA Satellite communication system

• US 4,285,064 A
• Filed: 09/28/1979
• Issued: 08/18/1981
• Est. Priority Date: 09/28/1979
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Hodge, Gene D.
• Primary Examiner(s): Safourek, Benedict V.
• Application Number:
  US06/079,927
• Time in Patent Office: 690 Days
• Field of Search: 375/3, 375/107, 455/12, 455/13, 370/93, 370/95, 370/97, 370/100, 370/103, 370/104, 370/112, 364/102, 364/107, 364/117, 364/514, 371/7, 371/11
• US Class Current: 455/13.1
• CPC Class Codes: H04B 7/2123 Variable assignment, e.g. demand assignment

Abstract

A time division multiple access satellite communication architecture is disclosed to achieve a relatively simple control procedure for permitting multiple computers to establish peer coupled transmission paths for high speed transfer by dynamically allocating satellite communication facilities in a sequentially shared broadcast mode. Each sequentially established CPU-to-CPU logical link takes the form of a point-to-multipoint sub-network which incorporates a standard data link control protocol for the control of information transfer. The function of the primary station is sequentially passed from station to station within the network and as each station assumes primary control of its logical point-to-multipoint circuit, other stations conform to the secondary role for that logical link configuration.

Claims

1. A network control method for a satellite communications network having a plurality of terrestrially based communication nodes, each node including a host computer, a communications controller, a modulator/demodulator, and an RF transmission/reception terminal, comprising the steps of:

assigning a first one of said nodes as a primary control node and the remaining ones of said plurality of nodes as secondary nodes in said network, establishing a first point to multipoint broadcast subnetwork within said network;

conducting two-way point to multipoint data transmissions from said first primary node to said first secondary nodes and transmitting commands via said satellite for link control;

transferring said primary control function from said first primary node to a second primary node selected from one of said plurality of first secondary nodes;

establishing point to multipoint data and control transmission from said second primary node to the remaining nodes in said network as second secondary nodes;

continuing the steps of passing primary control to successive ones of said nodes and said network and conducting point to multipoint broadcast data and control transmissions from the new primary node to the new secondary nodes;

whereby time devision multiple access communication between said nodes in said network division achieved.

2. A satellite communications controller being one of a plurality of such controllers for operation in a network having a plurality of communication nodes over a satellite link, each node having one such controller, the local controller assuming a primary control status while the remaining remote controllers in said network assume a secondary control status during a first point-to-multipoint broadcast subnetwork operation between said local controller and said remaining remote controllers, said local controller transferring said primary control function from itself to one of said remaining remote controllers establishing point-to-multipoint data and control transmission from said one of said remaining controllers while said local controller assumes a secondary control status, comprising:

a first level control means in said controller for implementing the point to multipoint subnetwork connection between said controller and said remaining controllers in said network;

a second level control means in said controller for passing the primary station status from one node to another over said satellite link;

whereby time division multiple access communication between said nodes in said network is achieved.

3. A satellite communications controller being one of a plurality of such controllers for operation in a network having a plurality of communication nodes over a satellite link, each node having one such controller, the local controller assuming a primary control status while the remaining remote controllers in said network assume a secondary control status during a first point-to-multipoint broadcast subnetwork operation between said local controller and said remaining remote controllers, said local controller transferring said primary control function from itself to one of said remaining remote controllers establishing point-to-multipoint data and control transmission from said one of said remaining controllers while said local controller assumes a secondary control status, comprising:

a first level control means in said controller for implementing the point-to-multipoint subnetwork connection between said controller and said remaining controllers in said network;

a second level control means in said controller for passing the primary station status from one node to another over said satellite link;

said first level control means further comprising;

a primary control processor for controlling the function of said local controller during its primary control status;

a secondary control processor for controlling the function of said local controller during its secondary control status;

a user input signal router having a control input connected to said primary control processor, a primary signal output and a secondary signal output, for steering said input signal into said primary or secondary signal output in response to said primary control processor;

a primary transmit burst buffer having an input connected to said primary signal output of said router and an output connected to said satellite link, for storing primary output signals to be transmitted over said satellite link during said primary control status of said local controller;

a secondary transmit burst buffer having an input connected to said secondary signal output of said router and an output connected to said satellite link, for storing secondary output signals to be transmitted over said satellite link in response to a transmit command for one of said remote controllers having the primary status, during said secondary control status of said local controller;

a satellite link input address decoder having an input connected to the satellite link, a primary link signal output and a secondary link signal output, for switching said link input to said primary link output or secondary link output in response to the coded representation of said link input address as being from a remote controller in said primary status or in said secondary status, respectively;

a primary link logic connected to said primary link output, for processing data messages transmitted from a remote controller in said primary status having a control input connected to said secondary control processor;

a secondary link logic connected to said secondary link output, for processing data messages transmitted from a remote controller in said secondary status, having a control input connected to said primary control processor;

a data sequencer having first and second inputs connected to said primary link logic and said secondary link logic and a user output, for arranging data messages output from said primary and secondary link logic into the order received over said satellite link;

whereby time division multiple access communication between said nodes in said network is achieved.

4. The controller of claim 3, wherein said second level control means comprises:

storage means connected to said primary control processor for storing the identity of the remote controller which will have the next primary control status;

control transfer signalling means connected to said primary control processor for transmitting to the remote controller identified in said storage means a control signal to initiate primary status operation, in response to said primary control processor;

control transfer signal acknowledgement means connected to said primary and secondary control processors, for receiving an acknowledgement signal from said remote controller identified in said storage means and initiating the transfer of control of said local controller from said primary to said secondary control processor, said local controller then assuming secondary control status.

5. The controller of claim 4, wherein said primary control processor initiates the operation of said control transfer signalling means at a predetermined time after primary control status was assumed by the local controller.

6. The controller of claim 4, wherein said primary control processor initiates the operation of said control transfer signalling means at a time after primary control status was assumed, the duration of which is proportional to the number of primary output signals stored in said primary transmit burst buffer.