Abstract: A system, various methods, and a specific apparatus are provided for the purpose of supporting push-to-talk (PTT) service for a very large group featuring a significantly higher number of listeners than the number of potential talkers, as well as a constrained vocabulary in normal usage. The invention takes advantage of speech-to-text and text-to-speech conversion in end user devices for maximum utterance compression. The invention uses the Iridium Mobile Satellite Service (MSS) system and its Short Burst Data (SBD) service for unicast transmission of talker utterances to a PTT Server, and the same system's Global Data Broadcast (GDB) service for multicast retransmission of utterances from the PTT Server to an effectively unlimited number of listeners. The PTT Server provides priority ordering and preemption as necessary when multiple talkers provide near-simultaneous utterances, effectively managing the floor without interactive protocols among the talkers.

Abstract: An optical wireless communications system (1) comprises a server or transceiver hub (6) transmitting and/or receiving optical communications with geographically dispersed subscriber units (8) via optical beams. The transceiver hub (6) transmits a beam pattern that has an efficient, rectangular, flat-topped far field optical profile, thus permitting less complex and less expensive transceiver equipment to be employed in the transceiver hub (6) and in the subscriber units (8). In one embodiment, the transceiver hub (6) comprises an optical source (52, FIG. 3), an asymmetrical lens such as a cylindrical lens (60, FIG. 3), and a diffraction element such as a diffractive phase plate (65, FIG. 3). Various methods of shaping an optical transmission profile are also described.

Abstract: A radio telecommunication network (10) includes satellites (12) which project cells (30) on the surface of the earth. Mobile units (16) are alerted to incoming calls when they receive ring signals. Ring signal coverage parameter values are selected in response to differentiating data (46) which cause different ring signals to be activated for mobile units (16) which appear to be proximately located. An illumination area ring signal coverage parameter may have a value selected in response to differentiating data (46) so that larger illumination areas are used for higher speed mobile units (16"). A transmission power ring signal coverage parameter may have a value selected in response to differentiating data (46) so that higher power ring signals are used in specific situations identified by the differentiating data (46).

Abstract: A local exchange with limited access to outside communication systems is coupled to a global satellite communication system by a mobile exchange unit. The mobile exchange unit (MXU) provides access to the local exchange by relating one channel in the global communication system to many possible destinations in the local exchange. Multiple circuits of the local exchange are associated with a single mobile number. A gateway associated with the MXU associates an available radio channel with the calling subscriber. Multi-stage dialing is eliminated and a subscriber can directly dial a number of a party in the local exchange.

Abstract: A communication network (10) includes a constellation of satellites (12) in orbit around the earth. Gateways (14) communicate with the satellites (12), reside on the surface of the earth, and interface the network (10) to the local PSTN (18). User units (16) communicate with satellites (12) and provide communication services to users. A gateway (14) includes a mobile switching center (22), which connects half-calls, and an earth terminal controller (20), which occasionally overrides connections defined in the mobile switching center (22). When possible, communication paths connected at the mobile switching center (22) are intraswitched at a satellite (12) rather than being routed through the mobile switching center. However, when supplementary services are requested, the communication path is reconfigured back to the mobile switching center (22) so that additional signals may be inserted into the communication path.

Abstract: A communication network (10) includes a constellation of satellites (12) in orbit around the earth. Gateways (14) communicate with the satellites (12), reside on the surface of the earth, and interface the network (10) to the local PSTN (18). User units (16) communicate with satellites (12) and provide communication services to users. A gateway (14) includes a mobile switching center (22), which connects half-calls, and an earth terminal controller (20), which occasionally overrides connections defined in the mobile switching center (22). When possible, communication paths connected at the mobile switching center (22) are intraswitched at one or more satellites (12) rather than being routed through the mobile switching center. However, when supplementary services are requested, the communication path is reconfigured back to the mobile switching center (22) so that additional signals may be inserted into the communication path.