Motorola Corporation

Donald J Sabourin

Kenneth W Hines

Bradley T Sanders

James A Stephens

Vijay K Kapoor

Henry Joseph Happ, Iii

David Stephen Saewert

Jeffrey Stuart Dorin

Andrew Furiga

John A Grosberg

Gerry Van Daele

A method and apparatus for controlling routing within a communication system (10) modifies (258) routing tables (220, 230, 232, 234, 236) located within nodes (150) so that received data packets are not returned directly to their sending nodes. In response to detection (352) of a failed link, a node (150) modifies (354) its routing tables (220, 230, 232, 234, 236) to avoid the failed link. After notification (402) of the failed link, a control facility (28) responds by creating (404) commands that compensate for the failed link. The control facility (28) sends (404) the commands to at least the node (150) that detected the failed link. If not already performed by the control facility (28), the node (150) then modifies (364, 366) its routing tables (220, 230, 232, 234, 236) so that data packets are not returned to their sending nodes, and to avoid the failed link.

Responsive routing control method and apparatus

A method routes data packets between nodes in a satellite-based communication system based on header information contained in each of the packets. The header information which contains routing and overhead information indicates whether the packet header has been received without any errors and whether the payload is to be read and processed by the node currently servicing the packet or passed on to another adjacent node. This method works in systems that have packet delays or transmission impairments, such as satellite-based telecommunication systems.

Inter-satellite method for routing packets

A method (50) reconstructs messages from segments (30) which are received in an unknown order and at different times. Each segment (30) comprises a header (31) and payload information (38). The method (50) reconstructs messages from the received segments (30) by reassembling the order as specified in the header (31) of the segment (30). Once the message is reconstructed, the message is delivered. This method (50) is especially important in satellite-based communications where no guarantee exists that the messages will be received in a sequential order or at a specified time.

Method of reconstructing and delivering segmented messages

These methods allow payload control instructions to be transported to satellites in a constellation of satellites and to be activated at pre-assigned times across the constellation. These methods manage and distribute validated payload instructions according to an associated time-tag. The payload instruction methods support direct payload control as well as incremental table updates. The primary functions performed by the payload instruction methods include appending payload instructions to tables, replacing or deleting specific payload instruction in a table, and scheduling and distributing the execution of payload instructions according to an attached time-tag.

Methods for managing and distributing payload instructions

An AFC loop for controlling the frequency of a VCO including an A to D converter and divider for providing pulses at some frequency equal to or lower than the output of the VCO, a source of stable reference pulses and a counter constructed to count to a predetermined number and count the reference pulses in synchronism with the divided pulses, a second divider connected to divide the reference pulses by the predetermined number and means for subtracting the output of the second divider from the counter to provide a control voltage for the VCO which is proportional to the drift in frequency of the VCO from a mean frequency.

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Mesa, AZ, United States of America

Donald J Sabourin