Hughes Electronics Corporation

The Directv Group, Inc.

Chandra Joshi

Anthony Robert Noerpel

Chi-Jiun Su

Prabir Datta

David Alan Roos

Stephanie Demers

Xiaoping He

Gerard Stelzer

Channasandra S Ravishankar

Michael I Parr

Mohammad Soleimani

Dave Roos

James Hobza

Zhengping Gao

Neeraj Tewari

Yi Chen

Gerard P Stelzer

A system and a methodology to improve the end-user quality of service both in terms of response time and reliability for the transport of in-call DTMF signals in wireless systems, particularly in geostationary mobile satellite systems. The methodology encompasses several techniques to provide acceptable end-to-end quality of service for DTMF. A technique is applicable for transport of DTMF in the wireless subscriber to network direction, where DTMF digits are carried in the form of an out-band message. The central part of the technique is to allow multiple key presses in the same message, thereby increasing efficiency and throughput in long-delay environment. Another technique utilizes the vocoder's functionality to carry DTMF in-band, thereby reducing system complexity. The scheme makes the use of an integrated DTMF detector which can classify a given frame of signal into several classes so that the DTMF encoded packet can carry a unique pattern across the air-interface to the voice decoder at AT, which is capable of identifying the pattern. Another technique pertains to the use of a message based DTMF transport between two-ATs on a separate logical channel with a unique Service Access point Identifier (SAPI) providing guaranteed service for DTMF transport in an AT-AT call.

In-call DTMF transport for geostationary mobile satellite communication system

A mobile satellite communication system is provided to control the transfer of a terminal for a single-hop call from at least one of a clear mode and a ciphered mode with respect to a gateway station to a ciphered mode with respect to a satellite link connecting the terminal with another terminal for a single-hop, terminal-to-terminal call using a cipher key and an encryption algorithm common to the terminal and the other terminal. Frame number offset data, which indicates a mapping delay between received and transmitted time slots at the satellite, is provided to both terminals in a terminal-to-terminal call for ciphering synchronization.

Method for implementing ciphered communication for single-hop terminal-to-terminal calls in a mobile satellite system

An approach for immediate channel assignment in a wireless communications system involves receiving a channel request message from a wireless transceiver, the channel request message including a dialed party number; forming an immediate assignment message including a channel assignment; transmitting the immediate assignment message to the wireless transceiver; and establishing a communications channel between the wireless transceiver and a called party by establishing a channel between the wireless transceiver and the called party.

Immediate channel assignment in a wireless system

An MSAT system is provided which optimizes satellite resources when implementing a single-hop TtT call. The system allocates satellite channels and signaling channels for a single-hop TtT call to the participating terminals at an early stage during the call set-up procedure such that only a single pair of satellite channels are assigned to each of the terminals for call establishment and for use during the call, as opposed to two pairs of satellite channels. A test message for signaling channel (e.g., TTCH) validation is transmitted from the network (e.g., from a gateway station controller) to each of the terminals.

Method for implementing a terminal-to-terminal call with an optimal use of radio resources in a mobile satellite system

A mobile satellite (MSAT) system is provided for establishing a single-hop terminal-to-terminal call between two terminals. The MSAT system maintains a signaling path between each terminal and a gateway station during the terminal-to-terminal call although a call path between the mobile switching center and the originating terminal is blocked by the satellite. During single-hop call establishment, satellite channels for the terminal-to-terminal call path and for signaling are allocated. The allocated channels are assigned when a direct satellite link for the terminal-to-terminal call is established; otherwise, the call can proceed as a double-hop call using previously assigned satellite channels. A verification signal is sent on the direct satellite link which is for processing by the terminals and which contains information that causes the signal to be ignored by a gateway station. During a single-hop terminal-to-terminal call, signaling from a destination gateway station to an originating terminal at another gateway station is sent via an intranetwork communication system connecting traffic control subsystems in different gateway stations and the satellite channels allocated to the originating terminal

Mobile satellite system and method for implementing a single-hop terminal-to-terminal call

An approach for error flow control in a communications system involves receiving a plurality of frames of data; determining in said plurality of frames of data, two or more contiguous defective frames of data, the two or more contiguous defective frames of data being followed by at least one frame of data in said plurality of frames that is not defective; forming a group reject message indicative of a range of the two or more contiguous defective frames; transmitting the group reject message; and receiving replacement frames, the replacement frames corresponding to the two or more contiguous defective frames, wherein said at least one frame that is not defective is not received again in response to the group reject message.

Error and flow control in a satellite communications system

A system and method for implementing single hop space segment terminal to terminal connections. The system includes a satellite-based radio frequency (RF) communication link for conveying multiple communication channels over the space segment via one or more spot beams. A terrestrial supervisory transceiver such as a gateway station is provided in communication with the satellite-based communication link. Mobile hand-held terminals (HHTs), herein first and second access terminals, may be located within one or more of the spot beams to communicate with one another via a single hop connection through a satellite of the system. A switch is provided for communication switching with the satellite of the system for the multiple communication channels to couple the first access terminal and the second access terminal over the space segment via one or more of the spot beams. The terrestrial supervisory transceiver or gateway is provided in communication with the satellite switch via the satellite-based communication link for implementing the single hop space segment terminal to terminal connection.

System and method for implementing terminal to terminal connections via a geosynchronous earth orbit satellite

An apparatus and method, for use with the satellite-based communications network, for improving the reliability and speed at which communication between a user terminal and the network is established. The apparatus and method arranges data of a channel request message transmitted from a user terminal to a satellite in the satellite-based network to insure that the most critical data for establishing communication between the user terminal and the satellite-based network is received at the satellite during the appropriate receiving time frame window. The channel request message includes a first data group necessary for establishing a communication link for which information is transmitted between the apparatus and the network, and a second data group including information for decreasing the amount time necessary to establish the communication link. The first data group is positioned at the center of the channel request message, with portions of the second data group at opposite ends of the channel request message. The time at which the user terminal transmits the channel request message is set based on a location of the apparatus within a spot beam, to take into account the appropriate propagation delay time for the message to travel from the apparatus to the satellite in the network, thus assuring that at least the first data group of the channel request message is received at the satellite during an appropriate receiving time frame window.

Apparatus and method for delivering key information of a channel request message from a user terminal to a network

An access terminal for initiating spot beam selection in a satellite communication system, in which the access terminal includes a receiver for measuring the received signal strength (RSS) of a multiplicity of radio frequency communication spot beam links. The access terminal is further provided with a microcontroller for comparing the received signal strengths from each of the multiplicity of spot beams to initiate information communication via a communication channel of the satellite communication system. In a described embodiment, the controller of the access terminal compares seven spot beam links to determine whether to initiate information communication with one of the seven spot beams received. Additionally, a memory coupled to the controller of the access terminal is used for storing spot beam identification information including the spot beam links assigned to the access terminal via the satellite communication system. The selection procedure employed by the system and method described facilitate a rapid selection of an appropriate spot beam identified from the multiplicity of radio frequency spot beam links received at a mobile access terminal.

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Gaithersburg, MD, United States of America

Chandra Joshi