Patent ID: 6850497
Filing Date: 2005-02-01
Classification: H04B

Abstract:
1. In a mobile satellite system including a satellite communication switching office having a satellite antenna for receiving/transmitting a satellite message via a satellite from/to a vehicle using a mobile communication system, a satellite interface system, a central controller receiving/transmitting the satellite message from/to the satellite communication switching office issued from the vehicle via the satellite and the satellite interface system, the mobile communication system comprising a user interface system providing a user interface through which a user has access to services supported by the mobile satellite system, an antenna system providing an interface between the mobile communication system and the mobile satellite system via the satellite interface system, and receiving a first satellite message from the satellite and transmitting a second satellite message to the satellite, a transceiver system, operatively connected to said antenna system, including a receiver and a transmitter, the transmitter converting the second satellite message including at least one of voice, data, fax and signaling signals into a modulated signal, transmitting the modulated signal to said antenna system, the transmitter including an amplifier, a first converter and associated first frequency synthesizer, a modulator, an encoder, multiplexer, scrambler and frame formatter for at least one of voice, fax, and data, the receiver accepting the first satellite message from the antenna system and converting the first satellite message into at least one of voice, data, fax and signaling signals, at least one of the voice, data and fax signals routed to the user interface system, the receiver including a second converter with an associated second frequency synthesizer, a demodulator, a decoder, demultiplexer, descrambler and frame unformatter for at least one of voice, fax, and data and a logic and signaling system, operatively connected to said transceiver, controlling initialization of the mobile communication system, obtaining an assigned outbound signaling channel from which updated system information and commands and messages are received, said logic and signaling system configuring said transceiver for reception and transmission of at least one of voice, data, fax and signaling messages, and controlling protocols between the mobile communication system and the mobile satellite system, and validating a received signalling messages and generating codes for a signaling message to be transmitted, a method of providing satellite communication between multiple users in a closed user group arrangement, said method comprising the steps of: (a) first and second mobile earth terminals (METS) registering with the mobile satellite system; (b) the first MET selecting a closed user group network identifier (NET ID) representing a NET group including the first and second METs to establish voice communication therewith; (c) the first MET transmitting the NET ID to the central controller; (d) the central controller receiving the NET ID, validating the first MET for communication, validating the NET ID, allocating a frequency for the NET group, and broadcasting the message to the NET group including the second MET informing the NET group of the allocated frequency and the voice communication associated therewith; (e) the second MET tuning to the frequency in response to the message broadcast by the central controller; (f) assigning by the central controller the first MET as current speaker for the NET group; (g) monitoring by the first and second METs whether at least one of a dispatcher message, a priority message and a release of speaker message has been issued, and if so, interrupting the current speaker with the at least one of the dispatcher message, the priority message and a new speaker; (h) monitoring by the central controller whether the current speaker is active, and if not, removing the current speaker and setting the current speaker to vacant; (i) notifying by the central controller the first and second METs that the current speaker is vacant; (j) initiating by one of the first and second METs a request to be the new speaker; (k) receiving by the central controller the request from a first of the one of the first and second METs to be the new speaker, and assigning the first of the one of the first and second METs as the new speaker; and (l) releasing the closed user group communication when no request from the one of the first and second METs is made to be the new speaker for a predetermined period of time.