Abstract: Modulation and coding schemes are provided for improved performance of wireless communications systems to support services and applications for terminals with operational requirements at relatively low Es/N0 ratios. The new modulation and coding schemes provide new BCH codes, low density parity check (LDPC) codes and interleaving methods.

Abstract: An apparatus, method, and system for quality of service over dedicated local loop networks is provided. Information regarding uplink and downlink speeds, and information regarding WAN interface protocol and encapsulation mode, is received from a network device. A link throughput limit is calculated based on the uplink speed of the network device, and a link throughput limit is set based on the calculated uplink throughput limit. An uplink network protocol overhead of the network device is calculated based on the WAN interface protocol and encapsulation mode of the uplink device and is factored in upstream available bandwidth calculations. Communication data size(s) are set based on the calculated uplink network protocol overhead. The downlink throughput limit is set to match the downlink speed based on the downlink speed and WAN network protocol overhead. The WAN network protocol overhead is factored in the downstream available bandwidth calculations and communication data sizes.

Abstract: An approach for allocating bandwidth is disclosed. A request is detected from a terminal for capacity on a communication channel based on type of traffic transmitted from the terminal. A bandwidth allocation pattern designated for the terminal is retrieved, wherein the bandwidth allocation pattern is set based on a predetermined service plan associated with the terminal. Bandwidth over the communication channel is reserved for the terminal according to the bandwidth allocation pattern without feedback to the terminal. This arrangement has particular applicability to a satellite network that provides data communication services.

Abstract: Systems and methods for performing preprocessing of received data packets, to reduce processing burdens and improve efficiency of communications terminal receivers, are provided. A first stage filter receives a data frame comprising data packets representing respective encapsulated fragments of a PDU. The first stage filter parses a header of one of the packets to locate a start field, and determines whether the start field indicates that the packet comprises a start fragment of the PDU. When the start field indicates that the packet comprises the start fragment, the first stage filter determines, based on packet label information of the packet header, whether to forward the packet to a second stage filter or to discard the packet, and forwards or discards the packet accordingly. When the start field indicates that the packet does not comprise the start fragment, the first stage filter forwards the packet to the second stage filter.

Abstract: A numerically controlled oscillator includes a phase accumulator configured to output a phase word, a clock configured to periodically output a clock signal in accordance with a delay interval, and a clock controller configured to adjust the delay interval. The phase accumulator is configured to output a new phase word in response to receiving the clock signal. An example method includes receiving a plurality of frequency control words, calculating a delay interval, accumulating the frequency control words in accordance with the delay interval to generate a phase word, and converting the phase word to a waveform.

Abstract: A signal transmission approach comprises encoding a source signal (comprising a plurality of source symbols) to generate a corresponding encoded signal. The encoded signal is modulated by mapping each source symbol to a respective signal constellation point of an applied signal constellation to generate a modulated signal. The modulated signal is pre-distorted based on a distortion estimate to generate a pre-distorted signal. The pre-distorted signal is filtered to generate a filtered signal. The filtered signal is frequency translated and amplified to generate a transmission signal for transmission via an uplink channel of a satellite communications system. To increase throughput, the source signal is processed through the apparatus and the resulting transmission signal is generated at a Faster-than-Nyquist (FTN) symbol rate and with a tight frequency roll-off.

Abstract: Approaches are provided for closing communications channel links (e.g., for small terminal applications in satellite communications systems), at lower effective data rates, in a most power efficient manner, while still meeting regulatory requirements. Such approaches employ modulation and coding schemes that facilitate such lower effective data rates in a most power efficient manner. The new modulation and coding schemes include new low density parity check (LDPC) codes.

Abstract: A system and methods that accommodate for nonlinear interference in a multi-carrier communications system are provided. A first signal is received by a receiver. The first signal comprises a source signal transmitted on a carrier over a communications channel. The first signal reflects a source symbol mapped to one of a plurality of signal constellation points, and each signal constellation point is associated with a different one of a plurality of signal clusters. A received representation of the source signal with respect to the source symbol is acquired from the first signal. A plurality of likelihood metrics are determined, where each likelihood metric is based on the received representation of the source signal with respect to the source symbol and a different one of a plurality of core parameters, wherein each core parameter is based on a centroid estimate with respect to a different one of the signal clusters.

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: An approach for transmission of data packets, based on virtual frame timing, over a communications channel is provided. A remote terminal receives a first stream of data packets at periodic time intervals. The terminal receives an allocation of time slots within a sequence of TDMA transmission frames, for transmission of the data packets over the channel. The timing structure of the allocated time slots is based on a virtual frame size relative to the interval timing of the first data packet stream, and independent of the frame size/timing of the TDMA transmission frames. The remote terminal may receive a second stream of data packets at periodic time intervals that differ from the time intervals of the first stream. In a multi-stream scenario, the virtual frame size for the time slot allocation is based on the greatest common denominator of the interval timings of the first and second data streams.

Abstract: Systems and methods for peer group diagnosis detection are disclosed. In an example embodiment, a beam profile including a plurality of satellite beam characteristics is determined. A peer group of satellite terminals is determined. Terminal profiles with terminal characteristics for the satellite terminals in the peer group are determined. A normalized baseline profile including normalized terminal characteristics for the peer group is determined. Measured operational statistics of the satellite terminals in the peer group are received and converted into normalized operation statistics using the terminal profiles and the normalized baseline profile. Normalized peer group operational statistics including a mean and a standard deviation of normalized operational statistics are determined. A normalized deviation of the normalized operational statistics is determined for each satellite terminal. The normalized deviations for each satellite terminal are compared to a threshold deviation.

Abstract: A dynamic and flexible architecture and methods for demodulation of high data-rate streams with high symbol-rates, such as in satellite communications systems or computer network communications systems, is provided. A data stream of a data transmission is received, the data stream corresponding to a plurality of data symbols. A plurality of data samples corresponding to each of the data symbols is generated. Further, one or more representative data samples, corresponding each of the data symbols, are generated based at least in part on timing control signals and the generated data samples for the respective data symbol. The generated data samples corresponding to each of the data symbols other than the representative data samples are dropped. The timing control signals are then adjusted based at least in part on the generated representative data samples.

Abstract: A method of providing a high symbol rate communication system with reduced overhead bandwidth includes calculating a minimum feasible aperture length at a network operations center, setting a hub demodulator subsystem to use an aperture length calculated from the minimum feasible aperture length, broadcasting the aperture length to a VSAT, and receiving an inroute data stream from the VSAT utilizing the aperture length.

Abstract: A device is provided for use with a satellite and a receiver having a local oscillator. The satellite is traveling in a vector and transmits a signal having an expected frequency. The receiver receives a received signal having a received signal frequency. The device includes: a Doppler shift measuring portion measuring a Doppler shift Dm; a predetermined Doppler shift storage portion storing a predetermined received Doppler shift Dp; a received signal Doppler shift error calculating portion calculating a received signal Doppler shift error De; a predetermined receiver position storage portion storing a predetermined position Pp of the receiver; and a receiver position estimating portion calculating an estimated receiver position Pe based on the predetermined position Pp of the receiver and the received signal Doppler shift error De.

Abstract: Aspects of the invention provide a system and method to allow inroute frame timing synchronization without the aid of hub signal loopback or satellite ephemeris data. Furthermore, it allows tracking and compensating of the satellite motion to allow multiple remotes to use TDMA on the inroute frequencies, while minimizing the aperture. Two main techniques proposed are CLT and polling based approaches, which are used in combination for an optimum solution. In CLT based approach, hub transmits remote specific timing correction feedback messages on the outroute on as needed basis. In polling based approach, the remotes derive their timing based on a per-beam average delay estimate broadcast by the hub and a measured local delay specific to each outroute stream from a remote. An aspect of the invention uses triangulation method to determine satellite position. Furthermore, an aspect of the invention uses hub burst arrival method instead of polling approach.

Abstract: A high capacity satellite communications system including a satellite with a beam for a forward downlink focused on a geographic area for which disproportionately higher capacity is desired, a hub located in a geographic area for which disproportionately lower capacity is desired, compared to the location of a VSAT, and the VSAT located in area where a beam for a forward downlink received by the VSAT from the satellite does not overlap with a beam for a return downlink received by the hub from a satellite.

Abstract: A physical layer (PL) frame generation method is provided. A PL payload is generated by encoding and modulating source data based on a first modcod of a first set. A synchronization header, comprising a first unique word (UW) (designed to facilitate efficient and reliable detection by terminals of a relatively low SNR operating range), and a modcod field (which indicates the first modcod scheme), is appended to the PL payload. A PL header is appended to the synchronization header and PL payload to form the PL frame. The PL header comprises a second UW and physical layer signaling (PLS). The PLS comprises encoded data fields reflecting a length of the PL frame, where the fields are encoded based on a second modcod scheme of a second set. The first modcod set is designed for SNR operating levels relatively lower than the SNR operating levels of the second modcod set.

Abstract: An apparatus includes a receiver component, a first signal processing component and a second signal processing component. The receiver component can receive a transmission signal, wherein the received transmission signal reflects an encoded and modulated initial source signal, amplified via a source transmitter, and transmitted over one or more channels of a wireless communications network. The first signal processing component can process the received transmission signal to generate a replica transmission signal that estimates the encoded and modulated initial source signal. The second signal processing component can determine an optimal parametric function for modeling the source transmitter, wherein the determination of the optimal parametric function comprises an iterative non-linear curve-fitting process, and wherein the optimal parametric function reflects one or more parameters of the source transmitter.

Abstract: A method for efficient retransmission over a satellite network including transmitting data packets to VSATs, receiving retransmission requests for at least one of the data packets from the VSATs, generating a retransmission packet based on the retransmission requests using XOR summing, transmitting the retransmission packet to the plurality of VSATs.

Abstract: The present invention provides an approach for FEC encoding based on intermediate code block lengths not associated with any supported mother FEC code. A first string of k2 data bits is received. The first string of data bits is encoded to generate an N2 bit code block for transmission over a channel of a wireless communications network. The first data bit string is encoded based on a supported (N1,k1) forward error correction (FEC) code of a code rate R=k1/N1, configured to encode a string of data bits of a length k1 bits to generate a code block of a length N1 bits. To facilitate the encoding of the first string of data bits based on the (N1,k1) FEC code, the encoding comprises padding, repeating and/or puncturing the first string of data bits and a resulting N1 bit code block to generate the N2 bit code block.