Abstract: An approach is provided for communicating in a meshed network including a first terminal and a second terminal. A request from the first terminal for obtaining address information of the second terminal is submitted to a hub. The hub generates a response including the address information and the context information that specifies capabilities of the second terminal. This arrangement has particular applicability to a satellite network (e.g., Very Small Aperture Terminal (VSAT) network) that provides data communication services.

Abstract: An approach for ranging in a radio frequency communications system is disclosed. A transmission channel class that includes at least one of transmission rate, modulation scheme, coding scheme, and transponder footprint is selected by a terminal. The terminal transmits a ranging message according to the selected transmission channel class over a channel. The transmission channel class is selectively modified based upon characteristics of the channel. Accordingly, an optimal transmission channel class is determined for a particular terminal. The above approach has particular applicability to a two-way satellite communications system.

Abstract: An approach for adaptively providing network performance enhancing functions in a secure environment, such as a virtual private network, is disclosed. Traffic, for example, Internet Protocol (IP) packets, is received for transport over an access network (e.g., satellite network). Next, characteristics (e.g., latency) of the access network are determined. A connection (which supports the performance enhancing functions) is selectively established based on the determined characteristics for transport the received packets over the access network. An encrypted tunnel is provided over the established connection to transmit the received packets.

Abstract: An approach is provided for supporting monitoring of network load. An allocation state is determined based on a bandwidth allocation value, a group load, and a guaranteed portion of capacity of a communication channel. The bandwidth allocation value specifies an actual amount of capacity of the communication channel allocated to one of a plurality of groups of terminals. The group load indicates loads of the terminals belonging to the one group. Capacity of the communication channel is assigned according to the determined allocation state. This arrangement has particular applicability to a satellite network that provides data communication services.

Abstract: A communication system balances message traffic between return channel groups and within the groups, so that the user does not control the specific transmission frequency used. Uplink frequencies and bandwidths for the return channels are set by the system in a return channel control message in the broadcast signal so as to account for system and return channel group loading, and to account for user message backlogs. An initial transmission from a remote user may be made using an ALOHA-type burst signal that provides a message backlog to the control station, and is made on a frequency determined from a randomly weighted, load-based frequency selection process. The system, and not the individual users determine the frequency and channel allocations. For large backlogs or priority users, periodic bandwidth is provided.

Abstract: A hybrid gateway includes functionality that allows bandwidth on a network (such as a satellite link) to be dynamically allocated and enforced. The hybrid gateway compares the thresholds defined for a requesting terminal's level of service and its measured running average data throughput to determine if the requesting terminal's bandwidth should be reduced (throttled). The hybrid gateway intercepts requests made by the requesting terminals and, if necessary, reduces the advertized window size of requests made by the requesting terminal, thereby reducing the transmission speed of the link and therefore the bandwidth of the link.

Abstract: Systems and methods for interference cancellation for high spectral efficiency satellite communications enabling efficient utilization of available bandwidth through overlapping adjacent channels. Data information is received along with noise information, and a filter bank is adapted to receive and filter the waveform and output channel information including a combination of data signals and adjacent channel interference signals. The filter bank is further adapted to provide estimated data signals and to calculate estimated interference signals. One or more interference generating processors are adapted to receive the calculated estimated interference signals to enable the interference generating processor to generate interference signals corresponding to the calculated estimated interference signals. The interference generating processor subtracts the interference signals from the estimated data signals in order to output relatively more accurate estimated data signals.

Abstract: A system in which a personal computer sends messages into a TCP/IP network using a conventional dial-up link and downloads data from the TCP/IP network using a high-speed one-way satellite link. A preferred embodiment uses a conventional SLIP provider to connect to the TCP/IP network and uses a commercial software TCP/IP package that has a standard driver interface. A spoofing protocol compensates for the long propagation delays inherent to satellite communication.

Abstract: A network apparatus for providing performance enhancements of a communication network is disclosed. The network apparatus includes a plurality of communication interfaces that are configured to receive and to forward messages according to a prescribed protocol. The network apparatus also includes a plurality of modules configured to process the messages to effect performance enhancing functions. Further, the network apparatus includes a plurality of buffers that are configured to store the received messages and messages that are generated by one of the plurality of modules. A portion of the plurality of buffers is shared by the plurality of modules based upon execution of a particular one of the performance enhancing functions. Each of the plurality of buffers has a data structure that includes an expandable header to accommodate different message types. The present invention has particular applicability to a bandwidth constrained system, such as satellite network.

Abstract: A communications system includes a plurality of communications channels for transporting packets. The system also includes a gateway that is coupled to the communications channels. The gateway is configured to buffer a packet that is received over one of the communications channel from a first host in a queue and to determine a window value for maximizing transmission rate based upon occupancy of the queue. The gateway is configured to a second host according to a prescribed protocol to force use of the determined window value in the second host over another one of the communications channels. The present invention has particular applicability to an asymmetric bandwidth network, such as a two-way satellite system.

Abstract: A method for compensating for power variations in satellite communications includes measuring or estimating power variations for signals received at an earth-based terminal. The method also includes measuring or estimating changes in carrier-to-noise levels by a number of satellite terminals. The power variations may then be used to adjust the measured/estimated changes in carrier-to-noise (C/N) levels. The adjusted C/N levels may then be used to more accurately reflect actual network conditions and may be used in downlink power control related processing.

Abstract: An approach for performing synchronization is provided. Phase and timing offsets are first estimated in order to calculate a frequency offset. A receiver processes a signal received from a satellite and determine offset information. The receiver includes a phase estimator for estimating a phase offset of the received signal, a timing estimator for estimating a timing offset of the received signal, and a frequency estimator for deriving a frequency offset from the phase and timing offset. A determination is made as to whether the sampling was done at a peak wave point of the data.

Abstract: Spread spectrum receiver includes a delay locked loop (DLL) circuit for holding the synchronization of a despread signal with a received spread spectrum signal. The DLL circuit comprises a subtracter for generating a signal representative of a subtraction between first and second correlation signals, a positive feedback amplifier for amplifying the subtraction representative signal and a window comparator for producing a lock signal when the subtraction representative signal is positioned within a window width.

Abstract: A distributed, demand access local loop telephone system is disclosed. An optical fiber, or fibers, connect a central office and a plurality of remote units which are located near subscriber populations. Communications on the fiber is by high speed digital data stream which is comprised of a plurality of bit multiplexed PCM channels, each of bandwidth equivalent to a VF channel or greater. The remote units are connected to the subscriber equipment (e.g. telephones or other data sources/sinks) by subscriber dedicated links (e.g. wire pairs or other cabling), and the remote units may be added, subtracted, or moved along the fiber path to reconfigure the overall system. Because of the demand access nature, the fiber bandwidth can be dynamically redistributed among the remote access units at high speed and controlled at the central office. The topology of the system can also be reconfigured, within limits, from a central site.

Abstract: A collision detection mechanism includes a transmission protocol which locates a gap in a station's transmission, of fixed duration and position, relative to start of transmission. Collision detection is enhanced since random timing of collisions normally results in filling in the gap. This condition is more readily detectable than detecting the simultaneous presence of energy from two transmitters. The transmission protocol is followed unless the transmitting station detects a collision, in which event gap creation is inhibited. The gap detecting equipment may be located at a network head end.