Abstract: A user terminal includes a processing device and a memory storage device. The user terminal is programmed to receive a forward link signal from at least one of a plurality of network devices and transmit a return link signal to the plurality of network devices. The user terminal is further programmed to select one of the plurality of network devices and transmit the return link signal to the selected one of the plurality of network devices at an optimized return link signal transmission strength. The network device is programmed to receive the return link signal from at least one of a plurality of user terminals, determine an initial offset associated with the return link signal, and transmit the initial offset and an original forward pilot to total transmit power ratio over a broadcast channel to the at least one of the plurality of user terminals.

Abstract: Approaches for efficient, dynamic and continuous handover processes, which encompass selection of an optimal path (consisting of a satellite, a satellite beam and carrier frequency set) over which a mobile user terminal (UT) communicates with the radio access network in a mobile satellite communications system, are provided. A set of path factors are determined regarding each of a plurality of communications paths for the UT. A path selection metric (PSM) for each communications path is determined, wherein the PSM for each communications path is determined via a weighted calculation based on the respective set of path factors for the communications path. A decision is made as to whether to perform a handover of the UT from a first of the communications paths to a second of the communications paths, wherein the determination is based on an evaluation performed based at least in part on the PSM.

Abstract: A system is provided for reducing latency data collection from space-based sensor satellites. A mobile vehicle platform includes a sensor module configured to monitor certain conditions, circumstances, environments and situations occurring on or around, or associated with, the Earth, and to generate sensor data resulting from the monitoring. A relay satellite terminal is configured to execute data communications via a communications channel of a first satellite beam, wherein the data communications are configured to relay the sensor data, via satellites, to respective gateways for forwarding to a central processing facility for one or more of aggregation, processing, analysis and dissemination of the data. The relay satellite terminal is further configured to switch the data communications from the communications channel of the first satellite beam to a communications channel of a second satellite beam based on a position of the relay satellite terminal relative to the first and second satellite beams.

Abstract: A resource efficient approach for push-to-talk (PTT) services over a mobile communications network is provided. A remote terminal (UT) receives a command for initiating a PTT session. The UT generates a RAB binding create message, including a PTT session identifier and RAB binding information, and transmits the RAB binding create message to a wireless gateway. The UT receives a RAB binding response from the wireless gateway, and performs a protocol signaling process for establishing PDP bearers, and for establishing the PTT session on a PTT server. The UT receives a command for initiation of media transmission for the PTT session, generates talk burst (TB) request message, and transmits the request message to the wireless gateway (the TB request message is transmitted via media access control (MAC) layer control messaging). In response, the UT receives a talk burst grant message from the wireless gateway.

Abstract: A broadband satellite communications system comprises forward error correction (FEC) encoder/decoder, interleaver/deinterleaver, puncturing/de-puncturing, scrambler/descrambler, bit to symbol mapping/de-mapping devices, modulator/demodulator, transmit and receive filter; operating in a time-division multiple access (TDMA) system where information is sent in a burst-by-burst fashion during the assigned time slot; supporting diverse traffic types such as voice over internet protocol (VOIP), control messages (DACCH) and keep alive burst (KAB) during silence period and multiple data rates.

Abstract: An approach for inter-gateway interference estimation and admission control is provided. A gateway receives return link signals, each being received via a satellite from a respective user terminal (UT) located within a satellite beam serviced by the gateway. A transmit power factor and an interference factor are determined for each UT based on the respective return link signal. A total interference factor is determined for the UTs based on the transmit power factors and the interference factors. A residual capacity level for the satellite beam is determined based on the total interference factor and a noise power factor. The gateway receives an admission request from a further UT requesting admission for transmission of a return link signal. The gateway determines whether to grant the admission request based on a required capacity level for the return link signal of the further UT relative to the residual capacity level.

Abstract: An approach provides a satellite air interface to efficiently support communication with a terrestrial network. One or more packets associated with a data communication session are received from a terrestrial network configured to provide cellular communications. A frame representing the packet for transmission is generated over a satellite link to a user terminal. Signaling information for the transmission of the packet over the terrestrial network is modified or eliminated for transmission over the satellite link.

Abstract: Approaches are provided for an SDSN that employs a satellite network nodes, where central L2 network nodes are controlled via a centralized Controller. Link status information is obtained regarding links of each L2 node. Global routing constraints, satellite ephemeris data, and resource allocation information are obtained. A constellation topology of the network nodes is determined based on the ephemeris data. Network routes between pairs of endpoints are determined. Each route includes links based on the link status information regarding the links, the global routing constraints, the bandwidth resources of the links and the current allocation of bandwidth resources, and/or the constellation topology. A forwarding table is generated for each network node, wherein each forwarding table includes route entries providing a next hop indicating a destination for data packets, wherein the destination is associated with a link of the respective network node that represents a link of a respective route.

Abstract: A system and method is provided to enable enhanced paging for 3GPP IMS based Mobile Satellite Communication is presented. The method is achieved by utilizing the network requested secondary PDP context activation (NRSPCA) features of 3GPP release 7. NRSPCA involves interaction between P-CSCF, GGSN, and SGSN that eventually allows SGSN to identify the traffic type of the incoming call without looking at the compressed SIP messages. RAN can do enhanced paging, if necessary; based on the request secondary PDP context activation message, if the Paging Cause is indicating conversational class. In another embodiment, enhanced paging can be achieved by marking the packet with an appropriate DSCP code, which is done by the P-CSCF. SGSN can populate the paging cause with enhanced paging code based on the DSCP code provided or RAN can escalate paging to enhanced paging by examining the DSCP code.

Abstract: A system is provided for reducing latency data collection from space-based sensor satellites. A mobile vehicle platform, configured to travel around the Earth, includes a sensor module and a relay satellite terminal. The sensor module monitors certain conditions, circumstances, environments and/or situations occurring on or around, or associated with, the Earth, and generates sensor data resulting from the monitoring. The relay satellite terminal executes data communications with a first of a plurality of satellites while the mobile vehicle platform is in a first area within a communications range of the first satellite, and, upon moving to a second area within a communications range of a second of the plurality of satellites, the relay satellite terminal switches the data communications to the second satellite. The data communications relay the sensor data, via the satellites, to a central processing facility for aggregation, processing, analysis and/or dissemination of the data.

Abstract: Approaches for efficient, dynamic and continuous handover processes, which encompass selection of an optimal path (consisting of a satellite, a satellite beam and carrier frequency set) over which a mobile user terminal (UT) communicates with the radio access network in a mobile satellite communications system, are provided. A set of path factors are determined regarding each of a plurality of communications paths for the UT. A path selection metric (PSM) for each communications path is determined, wherein the PSM for each communications path is determined via a weighted calculation based on the respective set of path factors for the communications path. A decision is made as to whether to perform a handover of the UT from a first of the communications paths to a second of the communications paths, wherein the determination is based on an evaluation performed based at least in part on the PSM.

Abstract: A synchronization approach is provided that compensates for the large Doppler offset of the satellites in a LEO satellite system by exploiting the predictable and deterministic nature of the Doppler component, and thereby simplifies the delay and the Doppler domain uncertainty ranges that the physical layer receivers have to resolve. The compensation is based on the known ephemeris information of the LEO satellite and the known positions of the gateway (GW) and the user terminal (UT) on the ground. Utilizing the deterministic component of the LEO Doppler, the synchronization process continually tracks and compensates for the time-varying offsets between the GW and UT frame timing, frame numbering (FN), symbol timings, and Doppler-induced scaling of center frequency and the signal bandwidth.

Abstract: An approach is provided for high penetration alerting in a mobile satellite system. A message is generated for transmission to a wireless terminal. The message is partitioned into a number of symbols, each symbol composed of a portion of the message. The symbols are encoded via FEC coding to generate outer coded symbols, and each outer coded symbol is encoded based on a corresponding binary orthogonal sequence. The inner coded symbols are modulated based on a binary modulation scheme, and pulse shaped to generate message bursts for transmission to the wireless terminal. Each message burst reflects a group of the inner coded symbols, wherein the grouping of the inner coded symbols facilitates joint sequence detection by the wireless terminal, and each message burst exhibits relatively low peak-to-average power ratio.

Abstract: A method for iterative estimation of a set of unknown channel parameters in a beamforming network including determining a first order estimate of offsets at measurement nodes and an estimate of the confidence in the initial estimate of the measurement nodes' offsets, and iterating, until a desired estimation accuracy is obtained, determining an improved estimate of a parameter set, and the confidence in the estimates, using the prior estimate of the offsets at the measurement nodes and determining an improved estimate of the offsets at the measurement nodes and the associated confidence values using the prior estimate of the parameter set and the corresponding confidence values.

Abstract: Various approaches are introduced to provide link adaptation to maximize the resource utilization of the satellite network: (i) a method to adapt the transmission rate for packet voice and data traffics; (ii) a method to control the transmit power of packet voice and data channels; and (iii) a method to accomplish the feedback loop in a secured and correct manner.

Abstract: Approaches for resource efficient multicast communications in mobile satellite systems are provided. A wireless gateway is configured to encapsulate multicast signaling messages received from participating remote terminals. The encapsulation is compatible with the core network of the system, whereby the signaling is passed through the core network undetected. The signaling is received by a multicast gateway, and provides necessary IP and port addressing information for the multicast gateway to encapsulate the multicast session data in a manner compatible with the core network. Upon receiving multicast session data from a multicast server, the multicast gateway replicates and encapsulates each data packet with IP and port addressing for each participating remote terminal, which is also passed through the core network undetected.

Abstract: An approach provides for conversion of global positioning system (GPS) data. A user terminal receives positioning data from a base station, wherein the positioning data is received in a second format, and wherein the second format was derived from ephemeris data broadcast via a global positioning system (GPS) in a first format. The user terminal converts the positioning data from the second format into a third format that is compatible with a protocol of the GPS system, and determines a first fix using the third format of the positioning data.

Abstract: An approach for improved security protocols in a mobile satellite system is provided. A remote terminal performs a key establishment function, including determination of a first encryption key for encrypting data for transmission over the satellite communications channels, and determination of an authentication key for authenticating entities communicating over the communications channels. The remote terminal receives a security mode command including a key indicator, and determines a second encryption key for enhanced session data security over communications channels. The second encryption key is determined based on the key indicator and a key generation algorithm. The remote terminal further determines a key indicator response and transmits a security mode complete command including the key indicator response to a satellite base station subsystem (SBSS).

Abstract: A system is provided for reducing latency data collection from space-based sensor satellites. A mobile vehicle platform includes a sensor module configured to monitor certain conditions, circumstances, environments and situations occurring on or around, or associated with, the Earth, and to generate sensor data resulting from the monitoring. A relay satellite terminal is configured to execute data communications via a communications channel of a first satellite beam, wherein the data communications are configured to relay the sensor data, via satellites, to respective gateways for forwarding to a central processing facility for one or more of aggregation, processing, analysis and dissemination of the data. The relay satellite terminal is further configured to switch the data communications from the communications channel of the first satellite beam to a communications channel of a second satellite beam based on a position of the relay satellite terminal relative to the first and second satellite beams.

Abstract: An approach is provided for high penetration alerting in a mobile satellite system. A message is generated for transmission to a wireless terminal. The message is partitioned into a number of symbols, each symbol composed of a portion of the message. The symbols are encoded via FEC coding to generate outer coded symbols, and each outer coded symbol is encoded based on a corresponding binary orthogonal sequence. The inner coded symbols are modulated based on a binary modulation scheme, and pulse shaped to generate message bursts for transmission to the wireless terminal. Each message burst reflects a group of the inner coded symbols, wherein the grouping of the inner coded symbols facilitates joint sequence detection by the wireless terminal, and each message burst exhibits relatively low peak-to-average power ratio.