Abstract: Methods efficiently assign user channels in a LEO (low-earth orbit) telecommunication system. These methods adapt the channel reuses based on system load or demand. These methods achieve high capacity and minimize interference for the particular situation. Since these methods are adaptive, they adjust to maintain efficient operation as the load conditions change.

Abstract: A method and apparatus for controlling communication channel access in a communication system (10) determines channel allocations (106) which represent limits on communication channel access and conforms operations of the system (10) to the channel allocations. The channel allocations are determined by dividing a surface which emanates signals from communication units (26) into elemental areas, collecting past traffic data (102) describing past communication channel usage by the communication units (26) located in the elemental areas, generating a traffic model (104) for a future time interval based on the past traffic data, and determining the channel allocations (106) based on the traffic model.

Abstract: A method and apparatus for establishing communication links between communication units that travel in different, determinable directions. The method includes the steps of calculating communication link boundary corridors, generating operational plans that inform the communication units how to establish and maintain a communication link, transmitting the operational plans to the communication units, and establishing links according to the operational plans. The apparatus includes a control segment that generates the operational plans and transmits them to the communication units.

Abstract: In a system that includes a constellation of satellite communication nodes, information packets are routed through the constellation using routing tables stored in each communication node. When a packet is received at a node, the packet's destination and routing table ID are read. One of several routing tables are selected using a mapping table. Each of the several routing tables has a different routing instruction set. The packet is routed away from the node using the selected routing table. When system traffic is heavy, or some of the communication links are overloaded or have failed, routing table control bits are sent to the nodes updating the mapping table. Packets are subsequently routed using different sets of routing tables, such as ones having greater hop counts.

Abstract: A method and apparatus for balancing data packet routing through a communication system (10) and for routing data packets based on their type is accomplished by using multiple routing table pages (152, 154) and page maps (180, 190) stored in nodes (100-112). For a given data packet type, a first page map (180) is used to select a routing table page (152, 154) so that only certain types of data may be routed through a target node (100). In a test mode, a neighboring node (102-112) will be configured such that it can route test data packets through the target node (100) while not routing other types of data packets through the target node (100). For a given routing number, a second page map (190) is used to select a routing table page (152, 154) so that traffic loads are balanced throughout the system (10).

Abstract: In a system that includes a constellation of satellite communication nodes, information packets are routed through the constellation using routing tables stored in each communication node. The routing tables are generated and updated regularly to reflect anticipated traffic loading and physical changes in node connectivity within the constellation which occur as a result of satellite motion and link failures. The table generating process performs a routing simulation using historical traffic data. Forward and reverse link usage for data packets headed for the same destination are identified and canceled. New routes are then generated. Popularity ratios are formed at each exit link for each destination node based on the new routes. Several routing tables are generated for each node based on selected packet splitting numbers and the popularity ratios. The routing tables are sent to each communication node for use during the next twenty-four hour period.

Abstract: Information packets are routed among a constellation of satellite nodes in a communication system in a distributed, yet systematic fashion. Routing tables for each node are generated in advance by a recursive process that considers link usage and anticipated link loading for different times and states of the constellation. Routing tables are generated centrally, distributed to, and maintained in each satellite node. The routing tables are updated regularly to reflect anticipated traffic loading and physical changes in node connectivity within the constellation which occur as a result of satellite motion. The tables are also updated responsively to reflect changes in network connectivity which occur because of failures that may occur in the cross-links or satellite nodes.

Abstract: A communication system (10) communicates real time data through a channel (26) that imposes delays of variable duration on signals propagating therethrough. The channel (26) may be established between a fastmoving satellite (14) in an orbit (28) around the earth and a subscriber unit (24) located proximate the earth' surface. The real time data are generated synchronously (124) at the subscriber unit (24) with a TDM frame (40) established by the satellite (14). The data are delayed in a variable delay circuit (68) before transmission through the channel (26). The duration of the delay imposed by the delay circuit (68) varies in response to timing data received from the satellite (14). The timing data describe a changing propagation delay for the channel (26) and changing definitions for TDM time slots (42', 44') Data received at the subscriber unit (24) are delayed in another variable delay circuit (76).