Abstract: A called subscriber unit's geographic location is provided by a gateway and translated to location coordinates of a global coordinate system. The gateway identifies an orbiting satellite communication station servicing the subscriber unit's location, and sends the subscriber unit's ID and location data to the satellite. The subscriber unit's location data is translated to an angle and range relative to the satellite's nadir using the satellite's ground track data. The angle and range are mapped to an antenna beam where the subscriber unit is located using a look-up table onboard the satellite. An acquisition or ring-alert signal is transmitted within the antenna beam where the subscriber unit is located. When the range is outside the satellite's footprint, the subscriber unit's ID and location data are routed directly to another satellite currently servicing that location.

Abstract: A cellular communications network includes satellites which project cells toward the earth. The satellites and cells move relative to the earth. When a call is being set up to a subscriber unit, data describing the subscriber unit's location are sent to a switching office of the network. The switching office generates a schedule which forecasts when movement of the cells will cause the subscriber unit to cross cell boundaries. During an ongoing call, the subscriber unit 5 determines when scheduled boundary crossings occur. So long as an adequate signal is present in a scheduled cell and network capacity exists in the scheduled cell to handle the call, the call will be handed off to the scheduled cell. The subscriber unit also monitors signal strengths to determine when a traffic channel's signal is getting weak and when an alternate cell's signal is stronger.

Abstract: A communication network keeps track of the locations of mobile units which utilize the network. On powering up, the mobile units determine their current locations using signals broadcast, for example, by overhead satellites. They then send data communication messages to the network describing their locations. The network saves the locations and returns data messages that describe borders which surround the mobile units' locations. The mobile units repetitively determine their current locations on a regular schedule. When their current locations are outside of their prescribed borders, they send other location data messages to the network to update the location data being maintained by the network and to receive a definition of a new border.

Abstract: Data packets are delivered through a constellation of nodes to a termination unit. The node where a packet leaves the constellation is a terminal node. Each packet includes a routing code. When a node receives a packet, it examines the routing code to determine if that node might be the packet's terminal node. A table look up operation is performed using the routing code as an index to a routing table. The table identifies a link to use in routing the packet away from the node to a neighbor node. The packet is also examined to verify compatibility between packet type and a selected link. If an incompatibility exists, a substitute link is selected. When a node concludes that it might be a terminal node for a packet, it evaluates a channel identifier to determine if it is currently serving the party to whom the packet is directed.

Abstract: A distributed communication network includes switching offices (SOs), moving-orbit satellites, and subscriber information managers (SIMs). A population of mobile units (MUs) communicates through the network. A MU automatically determines its location and communicates with the network so that this information is kept current at a SO serving the MU and at a home SIM for the MU. The terrestrial nodes of the network have information showing which MUs are logged on at any given time. This knowledge is used to block calls to MUs known to be logged off. Calls are setup through cooperation between SOs. When calls are being setup to MUs, call-originating SOs determine appropriate SIMs and obtains the current location of the MUs from those SIMs. This current location corresponds to a call-destination SO with which the originating SO may cooperate in setting up a call.

Abstract: A communications network includes satellites, which serve as switching nodes and move in orbits about the earth. The network additionally includes stationary switching offices. Mobile communication units communicate with the network through the satellites using TDMA data packets and network control messages. The switching offices couple to PSTNs. Each mobile unit is managed by a nearby switching office that assigns a logical channel identification (LCID) value to the unit. The unit and network use the LCID value to identify the unit in network communications so that network resources are conserved. The network insures that LCID values assigned to opposing parties in a call are included in all TDMA data packets transported to the opposing parties. Satellites and switching offices use these LCID values as logical channel assignments which do not change throughout the duration of the call, in spite of movement by satellites.