A multiple-access transceiver handles communications with mobile stations in environments that exceed mobile station design assumptions without necessarily requiring modifications to the mobile stations. One such environment is in Earth orbit. The multiple-access transceiver is adapted to close communications with mobile stations while exceeding mobile station design assumptions, such as greater distance, greater relative motion and/or other conditions commonly found where functionality of a terrestrial transceiver is to be performed by an orbital transceiver. The orbital transceiver might include a data parser that parses a frame data structure, a signal timing module that adjusts timing based on orbit to terrestrial propagation delays, frequency shifters and a programmable radio capable of communicating from the Earth orbit that uses a multiple-access protocol such that the communication is compatible with, or appears to the terrestrial mobile station to be, communication between a terrestrial cellular base station and the terrestrial mobile station.

A computer system is provided that includes devices configured to acquire input data. The system further includes a remote node (RN) configured to receive a first packet from a control node (CN). The first packet includes a packet header including a master timestamp, first control data and a CRC. The RN is also configured to verify integrity of the first control data based on the received CRC, generate and transmit to the CN a second packet. The second packet includes a packet header which includes a remote timestamp. The system also includes a CN connected with the RN via high-speed serial interfaces. The CN is configured to receive the second packet, determine status of the first packet based on the control data included in the second packet and configured to retransmit the first packet or generate and transmit a third packet based on the determined status of the first packet.

Various arrangements are presented for using an estimated timing advance for user equipment communications. A location of an instance of user equipment may be determined. A first estimated distance between the user equipment and a communication satellite may be determined using the determined location of the user equipment and an estimated satellite location. A second estimated distance between the communication satellite and a communication network gateway may be determined. An estimated timing offset using the calculated first estimated distance and the determined second estimated distance may be determined. An uplink data frame may be transmitted by the user equipment to the satellite such that a timing of transmission of the uplink data frame is based on the calculated estimated timing offset.

Various arrangements are presented for using an estimated timing advance for user equipment communications. A location of an instance of user equipment may be determined. An estimated distance between the user equipment and a communication satellite may be determined using the determined location of the user equipment and an estimated satellite location. An estimated timing offset using the calculated estimated distance may be determined. An uplink data frame may be transmitted by the user equipment to the satellite such that a timing of transmission of the uplink data frame is based on the calculated estimated timing offset.

Devices, methods, and systems for uplink synchronization in time division multiple access (TDMA) satellite network. In one embodiment, an earth-based satellite terminal is configured to communicate with a satellite hub through a satellite using the TDMA communication protocol. The earth-based satellite terminal is configured to determine its own location, a location of the satellite, estimate a distance between the location of the terminal and the location of the satellite, determine a Coarse Timing Advance based on the distance that is estimated, and transmit data to the satellite based on the Coarse Timing Advance and the TDMA communication protocol. The Coarse Timing Advance may allow uplink TDMA communication without a preamble transmission on a random access channel, the preamble transmission being required in many conventional systems.

A multiple-access transceiver handles communications with mobile stations in environments that exceed mobile station design assumptions without necessarily requiring modifications to the mobile stations. One such environment is in Earth orbit. The multiple-access transceiver is adapted to close communications with mobile stations while exceeding mobile station design assumptions, such as greater distance, greater relative motion and/or other conditions commonly found where functionality of a terrestrial transceiver is to be performed by an orbital transceiver. The orbital transceiver might include a data parser that parses a frame data structure, a signal timing module that adjusts timing based on orbit to terrestrial propagation delays, frequency shifters and a programmable radio capable of communicating from the Earth orbit that uses a multiple-access protocol such that the communication is compatible with, or appears to the terrestrial mobile station to be, communication between a terrestrial cellular base station and the terrestrial mobile station.

A method and a system for multi-user transmission in a network, comprising at least on network control center NCC and one or more terminals, wherein the method comprises at least the following steps: determining the number of 4D-TDMA carriers as a function of the number and needs of the terminals, determining the type (SCPC or TDMA) and frequency band Bi of each of the 4D-TDMA carriers as a function of the terminals transmitting on the carriers, for each frame, dividing the band B into PTDMA transmission channels and into PSCPC service channels, each channel consisting of frames comprising a plurality of slots, STDMA slots and SSCPC slots, dynamically allocating a plurality of slots of a 4D-TDMA carrier according to the services required by each terminal, configuring the coding and modulation scheme of each slot by taking account of the quality of the received signals.

A tool comprises a distal portion and a proximal portion spaced apart by a shaft along a longitudinal axis. The distal portion includes a distal link and the proximal portion including a proximal link. The distal link and proximal link form a pair of links. The tool also comprises a set of tension load bearing members connecting the proximal link and the distal link and terminating at the links of the pair to transfer movement therebetween. The tool also comprises an articulation lock positioned between the distal portion and the proximal portion and configured to allow through passage of the set of tension load bearing. The articulation lock is adjustable between an unlocked configuration in which the proximal and distal links are moveable and a locked configuration in which an effective length of the shaft is increased, creating a force to impede movement of the proximal and distal links.

A computer system is provided that includes devices configured to acquire input data. The system further includes a remote node (RN) configured to receive a first packet from a control node (CN). The first packet includes a packet header including a master timestamp, first control data and a CRC. The RN is also configured to verify integrity of the first control data based on the received CRC, generate and transmit to the CN a second packet. The second packet includes a packet header which includes a remote timestamp. The system also includes a CN connected with the RN via high-speed serial interfaces. The CN is configured to receive the second packet, determine status of the first packet based on the control data included in the second packet and configured to retransmit the first packet or generate and transmit a third packet based on the determined status of the first packet.

Techniques are disclosed for determining propagation delay of a first path and or of a second path which connect a first transceiver unit associated with a first clock to a second transceiver unit associated with a second clock in a communications network, based on a first time reference representing a time of transmission of a first signal from the first transceiver unit, a second time reference representing the time of receipt of the first signal at the second transceiver unit, a third time reference representing a time of transmission of a reply to the second signal from the second transceiver unit, and a fourth time reference representing the time of receipt of the reply to the second signal at the first transceiver unit.