Multiplex communications – Communication over free space – Repeater
Reexamination Certificate
1998-06-08
2001-09-18
Chin, Wellington (Department: 2664)
Multiplex communications
Communication over free space
Repeater
C370S328000, C370S339000, C370S349000, C455S412100
Reexamination Certificate
active
06292473
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to mobile communications terminal in wireless communications system. More specifically, the present invention relates to mobile communications terminals sending and receiving pre-formatted text and binary messages to a central facility using a satellite communications system.
DESCRIPTION OF THE RELATED ART
Wireless communications terminals have been used in service vehicles to receive communications messages from centralized dispatcher offices. For example, taxicab companies have installed data terminals in taxicabs that receive messages from a dispatcher via RF transmissions. Such systems, however, are limited in their communication abilities in that the mobile terminals can only receive and acknowledge messages.
One example of a currently successful and operational satellite based data service is INMARSAT's Standard-C Communications System. The major elements of the Standard-C system architecture include land or coast earth stations (LESs or CESs), and a network coordination station (NCS) in each ocean region and ship or mobile earth stations (SESs or MESs). Each CES serves as a gateway between the terrestrial network and the INMARSAT Standard-C communications system. The types of interface provided at the CES are decided by the coast earth station operator, however, Telex, EGC message processing and distress message handling are mandatory to comply with INMARSAT's Standard Definition Manual Version 1.3.1.
A SES or MES is the mobile earth station used by mobile subscribers. The system allows the use of very low G/T transceivers at the ship or mobile earth station (SES or MES). Standard-C uses all digital transmission techniques for both signalling and message data specifically based on a standard slotted ALLOHA TDMA protocol. SES equipment may therefore take advantage of the low cost trend of digital technology. Standard-C SESs do not require the use of a dedicated receiver for receiving signalling information.
The SES consists of a DCE (data circuit terminating equipment) providing the interface to the satellite network, and a DTE (data terminal equipment, for example a personal computer) which provides the user interface. For ship-to-shore message transfer, a message is formatted in the DTE and then transferred to the DCE for transmission. In the shore-to-ship direction, the DCE receives the complete message from the radio channel before passing it to the DTE for the attenuation of the user. The SES may be equipped for reception of Enhanced Group Calls (EGC) or a separate Receiver Only Terminal for EGC reception may be used. When idle, every SES tunes to and receives a TDC channel transmitted by the NCS; the NCS Common Channel. The channel is used to transmit announcements to SESs that shore-to-ship calls are ready at a CES for transmission to the SES. Enhanced Group Calls are also transmitted on this channel.
Additional optional services are available within the system and may be offered by CESs. These services include access to electronic mail and message handling services (X.400 for example), individual, group and area directed polling, and a data reporting service. The polling and data reporting services are primarily aimed at providing a service to remotely operated and land mobile terminals. More detailed information regarding the Standard-C protocol is disclosed in “INMARSAT Standard-C communications System” by Kevin Phillips, IEEE International Conference on Communications '88: Digital Technology—Spanning the Universe, Jun. 12-15, 1988, pp. 1117-1122 (Available from IEEE Service Cent (cat. #CH2538-7/88)) ©1988 IEEE, the disclosure of which is incorporated in its entirety by reference.
Standard-C protocol was not designed to be used in connection with land mobile data terminals but was designed only for maritime use. Thus, there is a need for a satellite communications system that provides effective communications for land mobile data terminals.
Conventional electronic mail and message handling services are not designed for extensive message transmissions in a satellite communication system. Service vehicles such as taxicabs, trucks, etc., need an efficient, low-cost, and reliable arrangement for receiving messages from a central dispatcher. Moreover, there is a need for providing advanced messaging capabilities where a variety of messages can be initiated mobile terminals without providing excessive loading on the satellite.
DISCLOSURE OF THE INVENTION
In view of the foregoing, there is a need for a low cost mobile communication system that provides efficient transport of user messages via a satellite network.
There is a also a need for an electronic mail messaging system for transporting messages between a dispatcher and mobile communication terminals that uses predetermined message forms to minimize user efforts in generating and displaying mail messages.
According to at least one aspect of the present invention, in a mobile satellite system including a satellite communication switching office having a satellite antenna for providing communication of a satellite message with a mobile communication system via a satellite, a central controller communicating with the mobile communication system via the satellite communication switching office, a communication method comprising storing a plurality of message display forms in the mobile communication system, each message display form having a predetermined display format and a form identifier, generating at the central controller a user message comprising message data, outputting from the central controller a satellite message carrying the message data and the form identifier of a selected one of the message display forms to the satellite communication switching office, transmitting the satellite message to the mobile communication system via the satellite, and displaying the satellite message received by the mobile communication system using a selected one of the stored message display forms corresponding to the form identifier in the transmitted satellite message. The communication method enables a central controller to send and receiver user messages in a compressed format, minimizing the amount of data to be transmitted to the mobile communications systems.
In another aspect of the present invention, in a mobile satellite system including a satellite communication switching office having a satellite antenna for providing communication of satellite messages with a mobile communication system via a satellite, a central controller communicating with the mobile communication system via the satellite communication switching office, the mobile communication system comprising a satellite transceiver communicating data packets carrying a first satellite message to the satellite in response to transceiver control signals a graphic user interface providing a display and accepting key inputs from a user, a software system comprising a middleware layer sending the transceiver control signals and packets carrying the satellite message to the transceiver, a network form controller storing a plurality of message forms each having a form identifier and a form definition specifying a predetermined format, an address list storing a list of station addresses identifiable by the satellite communication switching office for respective satellite stations having communication capabilities with the satellite communication switching office, a user interface controller retrieving a selected one of the form definitions and at least one station address in response to the key inputs, the user interface controller outputting a user message including the at least one station address, user inputs from the graphic user interface and the form identifier corresponding to the selected form definition, a network controller subsystem outputting the satellite message carrying the user message to the middleware layer, and an event handler controlling operations of the network controller and the user interface controller in response to network event and user event signals from the n
Barber Thomas A.
Duske, Jr. Frederick J.
Gruessing, Jr. Joseph A.
Self Dean A.
Chin Wellington
Donner Irah H.
Hale and Dorr LLP
Motient Services Inc.
Pham Brenda
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