Abstract: A communication system, a method of and an apparatus for communicating messages. N messages are transmitted from an originating station to a relaying station in a signal with frequencies within a bandwidth B, with each of the N messages having frequencies within a unique frequency band. Messages with adjacent frequency bands have the same or different bandwidths. At the relaying station, the messages are separated into groups of messages having the same bandwidth, where all messages in any group occupy non-adjacent frequency bands, and the messages of each group are then combined. Each combined group of messages is applied to a separate amplifier. Two or more messages of the same bandwidth may share a common traveling wave tube amplifier. Each amplified group of messages is then separated into separate messages which are transmitted to respective receiving stations.

Abstract: A satellite communication system (10) includes apparatus for exchanging communication data between ground-based user sites (21-24, 41-44 and 51-54) and a ground-based wideband network (60). A communication satellite (30) exchanges user communication data with the user sites. Ground-based hub terminals (27, 35, 47 and 57) exchange the user communication data with the satellite (30) and also exchange the data with the network (60). A communication manager (70) determines the communication requirements between the satellite and the network and identifies more than one hub terminal to exchange user communication data with the satellite in the event that one hub terminal is insufficient to meet the communication requirements.

Abstract: A satellite communication system (10) includes apparatus for exchanging communication data between ground-based user sites (21-24, 41-44 and 51-54) and a ground-based wideband network (60). A communication satellite (30) exchanges user communication data with the user sites. Ground-based hub terminals (27, 35, 47 and 57) exchange the user communication data with the satellite (30) and also exchange the data with the network (60). A communication manager (70) determines the communication requirements between the satellite and the network and identifies more than one hub terminal to exchange user communication data with the satellite in the event that one hub terminal is insufficient to meet the communication requirements.

Abstract: A communications satellite system 100 is provided that comprises a communications satellite 101, at least one user terminal 204 and at least one gateway terminal 202. The communications satellite 101 conveys communication signals between the user terminal 204 and the gateway terminal 202. The communications satellite system 100 includes a forward communication path 200 and a return communication path 300 through the communications satellite 101 between the user terminal 204 and the gateway terminal 202. At least one equivalent signal component is located in both the forward communication path 200 and return communication path 300 and operates on the communication signals. The equivalent signal component has substantially the same operating range in both the forward communication path 200 and return communication path 300 for at least one operating characteristic.

Abstract: A time division multiplex (TDM) communication system (10) for broadcasting to users. The TDM communication system (10) includes a first transmitter (14) which broadcasts a first signal into a first coverage area (30) and a second transmitter (16) which broadcasts a second signal into a second coverage area (30) which at least partially overlaps said first coverage area (30). The first transmitter (14) is allocated a first TDM time block (88) having a first guard time (48) and the second transmitter (16) is allocated a second TDM time block (88) having a second guard time (48). The first (88) and second time blocks (88) form at least a portion of a TDM repeat interval such that the first transmitter (14) broadcasts the first signal during the first TDM time block (88) and the second transmitter (16) broadcasts the second signal during the second TDM time block (88).

Abstract: A communication system (10) implemented to be specifically matched to the time and spatially dependent statistics of a transmission channel (36). The communication system (10) is used for broadcasting over the channel (36) to users in a coverage region (18). The communication system (10) includes a transmitter (12) having an error correction encoder (30) and a weighted interleaver (32). The error correction encoder (30) includes a first input to receive data bits and a first output. The error correction encoder (30) expands each data bit received at said input by an encoder rate. The weighted interleaver (32) includes a second input to receive the expanded data bits and a second output. The weighted interleaver (32) has a non-uniform delay distribution between a minimum delay and a maximum delay to interleave the expanded data bits by the non-uniform delay distribution.

Abstract: A digital audio radio system where multiple digital data versions of a single source signal are transmitted to one or more satellites to be rebroadcast to a defined reception area where the multiple versions are delayed with respect to each other. One of the signals is intended to be used by a mobile receiver if the transmission from the satellite is not blocked, and the other one or more versions are intended to be used if the broadcast signal from the satellites is blocked. Because the multiple versions represent the same source signal that is received at different times, if the signal from satellites is blocked, the signal being received at a different time can be used. The signals that are to be used when the broadcast signal is blocked can be of a lesser data quality to conserve system resources.

Abstract: A communication system (10) implemented to be specifically matched to the time and spatially dependent statistics of a transmission channel (36). The communication system (10) is used for broadcasting over the channel (36) to users in a coverage region (18). The communication system (10) includes a transmitter (12) having an error correction encoder (30) and a weighted interleaver (32). The error correction encoder (30) includes a first input to receive data bits and a first output. The error correction encoder (30) expands each data bit received at said input by an encoder rate. The weighted interleaver (32) includes a second input to receive the expanded data bits and a second output. The weighted interleaver (32) has a non-uniform delay distribution between a minimum delay and a maximum delay to interleave the expanded data bits by the non-uniform delay distribution.

Abstract: A weighted interleaving system (10) is used for correlated channel coding. The weighted interleaving system (10) includes a weighted interleaver (12) having a pseudo-random demultiplexer (18), a first branch (28), a second branch (30), a third branch (32) and a pseudo-random multiplexer (38). The pseudo-random demultiplexer (18) receives input data bits at an input (20) and randomly distributes the input data bits to first (22), second (24) and third (26) outputs of the pseudo-random demultiplexer (18). The first branch (28) in communication with the first output (22) delays the transmission of the input data bits routed to it by a minimum delay. The second branch (30) in communication with the second output (24) delays the transmission of the input data bits routed to it by a delay uniform in probability from the minimum delay to a maximum delay. The third branch (32) in communication with the third output (26) delays the transmission of the input data bits routed to it by the maximum delay.

Abstract: A power control method and apparatus are provided for a satellite based telecommunications system. The system includes a power control subsystem which is operative with systems operations center for distributing available satellite power between earth stations. Each earth station includes a baseband manager which subdivides the available satellite power between subband beams emitted from the satellite. The earth station further includes beam processors which manage the power allocated to each subband within an associated beam in order to maintain a desired signal quality in a forward link between the satellite and user terminals within the associated subbands. The beam processors communicate with modems, each of which is assigned to a particular user terminal. Each modem controls the satellites transmission power in the forward link to the user terminals to maintain a desired signal-to-noise ratio at the user terminal receiver. The signal-to-noise ratio is determined by the corresponding beam processor.

Abstract: A method and apparatus are provided, for maintaining synchronous return and forward communications links between user terminals and earth stations communicating via a common satellite in a satellite based telecommunications system. Each user terminal maintains a closed synchronization loop with its associated earth station based on timing and frequency error offset signals received by the user terminals. The user terminals update their internal timing and frequency generators based on the received error offset signals. In an earth station sharing embodiment, one of the earth stations is designated as a master earth station while the remaining stations are designated as slave earth stations with respect to a common satellite. The slave earth stations monitor a return link between at least one user terminal and the master earth station.

Abstract: A weighted interleaving system (10) is used for correlated channel coding. The weighted interleaving system (10) includes a weighted interleaver (12) having a pseudo-random demultiplexer (18), a first branch (28), a second branch (30), a third branch (32) and a pseudo-random multiplexer (38). The pseudo-random demultiplexer (18) receives input data bits at an input (20) and randomly distributes the input data bits to first (22), second (24) and third (26) outputs of the pseudo-random demultiplexer (18). The first branch (28) in communication with the first output (22) delays the transmission of the input data bits routed to it by a minimum delay. The second branch (30) in communication with the second output (24) delays the transmission of the input data bits routed to it by a delay uniform in probability from the minimum delay to a maximum delay. The third branch (34) in communication with the third output (26) delays the transmission of the input data bits routed to it by the maximum delay.